Author name code: cameron
ADS astronomy entries on 2022-09-14
author:"Cameron, Robert H." 
------------------------------------------------------------------------  

Title: Erratum: "Faculae Cancel out on the Surfaces of Active Suns"
    (2022, ApJL, 934, L23)
Authors: Nèmec, N. -E.; Shapiro, A. I.; Işık, E.; Sowmya, K.;
   Solanki, S. K.; Krivova, N. A.; Cameron, R. H.; Gizon, L.
Bibcode: 2022ApJ...936L..17N
Altcode:
  No abstract at ADS

Title: Faculae Cancel out on the Surfaces of Active Suns
Authors: Nèmec, N. -E.; Shapiro, A. I.; Işık, E.; Sowmya, K.;
   Solanki, S. K.; Krivova, N. A.; Cameron, R. H.; Gizon, L.
Bibcode: 2022ApJ...934L..23N
Altcode: 2022arXiv220706816N
  Surfaces of the Sun and other cool stars are filled with magnetic
  fields, which are either seen as dark compact spots or more
  diffuse bright structures like faculae. Both hamper detection and
  characterization of exoplanets, affecting stellar brightness and
  spectra, as well as transmission spectra. However, the expected facular
  and spot signals in stellar data are quite different, for instance,
  they have distinct temporal and spectral profiles. Consequently,
  corrections of stellar data for magnetic activity can greatly benefit
  from the insight on whether the stellar signal is dominated by spots or
  faculae. Here, we utilize a surface flux transport model to show that
  more effective cancellation of diffuse magnetic flux associated with
  faculae leads to spot area coverages increasing faster with stellar
  magnetic activity than that by faculae. Our calculations explain the
  observed dependence between solar spot and facular area coverages and
  allow its extension to stars that are more active than the Sun. This
  extension enables anticipating the properties of stellar signal and its
  more reliable mitigation, leading to a more accurate characterization
  of exoplanets and their atmospheres.

Title: Chromospheric extension of the MURaM code
Authors: Przybylski, D.; Cameron, R.; Solanki, S. K.; Rempel, M.;
   Leenaarts, J.; Anusha, L. S.; Witzke, V.; Shapiro, A. I.
Bibcode: 2022A&A...664A..91P
Altcode: 2022arXiv220403126P
  Context. Detailed numerical models of the chromosphere and corona are
  required to understand the heating of the solar atmosphere. An accurate
  treatment of the solar chromosphere is complicated by the effects
  arising from non-local thermodynamic equilibrium (NLTE) radiative
  transfer. A small number of strong, highly scattering lines dominate the
  cooling and heating in the chromosphere. Additionally, the recombination
  times of ionised hydrogen are longer than the dynamical timescales,
  requiring a non-equilibrium (NE) treatment of hydrogen ionisation. <BR
  /> Aims: We describe a set of necessary additions to the MURaM code that
  allow it to handle some of the important NLTE effects. We investigate
  the impact on solar chromosphere models caused by NLTE and NE effects in
  radiation magnetohydrodynamic simulations of the solar atmosphere. <BR
  /> Methods: The MURaM code was extended to include the physical
  process required for an accurate simulation of the solar chromosphere,
  as implemented in the Bifrost code. This includes a time-dependent
  treatment of hydrogen ionisation, a scattering multi-group radiation
  transfer scheme, and approximations for NLTE radiative cooling. <BR />
  Results: The inclusion of NE and NLTE physics has a large impact on the
  structure of the chromosphere; the NE treatment of hydrogen ionisation
  leads to a higher ionisation fraction and enhanced populations in
  the first excited state throughout cold inter-shock regions of the
  chromosphere. Additionally, this prevents hydrogen ionisation from
  buffering energy fluctuations, leading to hotter shocks and cooler
  inter-shock regions. The hydrogen populations in the ground and first
  excited state are enhanced by 10<SUP>2</SUP>-10<SUP>3</SUP> in the
  upper chromosphere and by up to 10<SUP>9</SUP> near the transition
  region. <BR /> Conclusions: Including the necessary NLTE physics
  leads to significant differences in chromospheric structure and
  dynamics. The thermodynamics and hydrogen populations calculated using
  the extended version of the MURaM code are consistent with previous
  non-equilibrium simulations. The electron number and temperature
  calculated using the non-equilibrium treatment of the chromosphere
  are required to accurately synthesise chromospheric spectral
  lines. <P />Movies associated to Fig. 2 are only available at <A
  href="https://www.aanda.org/10.1051/0004-6361/202141230/olm">https://www.aanda.org</A>

Title: Impact of spatially correlated fluctuations in sunspots on
    metrics related to magnetic twist
Authors: Baumgartner, C.; Birch, A. C.; Schunker, H.; Cameron, R. H.;
   Gizon, L.
Bibcode: 2022A&A...664A.183B
Altcode: 2022arXiv220702135B
  Context. The twist of the magnetic field above a sunspot is an
  important quantity in solar physics. For example, magnetic twist
  plays a role in the initiation of flares and coronal mass ejections
  (CMEs). Various proxies for the twist above the photosphere have been
  found using models of uniformly twisted flux tubes, and are routinely
  computed from single photospheric vector magnetograms. One class of
  proxies is based on α<SUB>z</SUB>, the ratio of the vertical current
  to the vertical magnetic field. Another class of proxies is based on the
  so-called twist density, q, which depends on the ratio of the azimuthal
  field to the vertical field. However, the sensitivity of these proxies
  to temporal fluctuations of the magnetic field has not yet been well
  characterized. <BR /> Aims: We aim to determine the sensitivity of twist
  proxies to temporal fluctuations in the magnetic field as estimated
  from time-series of SDO/HMI vector magnetic field maps. <BR /> Methods:
  To this end, we introduce a model of a sunspot with a peak vertical
  field of 2370 Gauss at the photosphere and a uniform twist density
  q = −0.024 Mm<SUP>−1</SUP>. We add realizations of the temporal
  fluctuations of the magnetic field that are consistent with SDO/HMI
  observations, including the spatial correlations. Using a Monte-Carlo
  approach, we determine the robustness of the different proxies to the
  temporal fluctuations. <BR /> Results: The temporal fluctuations of
  the three components of the magnetic field are correlated for spatial
  separations up to 1.4 Mm (more than expected from the point spread
  function alone). The Monte-Carlo approach enables us to demonstrate that
  several proxies for the twist of the magnetic field are not biased in
  each of the individual magnetograms. The associated random errors on
  the proxies have standard deviations in the range between 0.002 and
  0.006 Mm<SUP>−1</SUP>, which is smaller by approximately one order
  of magnitude than the mean value of q.

Title: Theory of solar oscillations in the inertial frequency range:
    Amplitudes of equatorial modes from a nonlinear rotating convection
    simulation
Authors: Bekki, Yuto; Cameron, Robert H.; Gizon, Laurent
Bibcode: 2022arXiv220811081B
Altcode:
  Several types of inertial modes have been detected on the
  Sun. Properties of these inertial modes have been studied in the
  linear regime but have not been studied in nonlinear simulations
  of solar rotating convection. Comparing the nonlinear simulations,
  the linear theory, and the solar observations is important to better
  understand the differences between the models and the real Sun. We
  wish to detect and characterize the modes present in a nonlinear
  numerical simulation of solar convection, in particular to understand
  the amplitudes and lifetimes of the modes. We developed a code with
  a Yin-Yang grid to carry out fully-nonlinear numerical simulations
  of rotating convection in a spherical shell. The stratification is
  solar-like up to 0.96R. The simulations cover a duration of about
  15 solar years. Various large-scale modes at low frequencies are
  extracted from the simulation. Their characteristics are compared to
  those from the linear model and to the observations. Among other modes,
  both the equatorial Rossby modes and the columnar convective modes
  are seen in the simulation. The columnar convective modes contain
  most of the large-scale velocity power outside the tangential
  cylinder and substantially contribute to the heat and angular
  momentum transport. Equatorial Rossby modes with no radial node (n=0)
  are also found: They have the same spatial structures as the linear
  eigenfunctions. They are stochastically excited by convection and have
  the amplitudes of a few m/s and mode linewidths of about 20-30 nHz,
  which are comparable to those observed on the Sun. We also confirm the
  existence of the mixed modes between the equatorial Rossby modes and
  the columnar convective modes in our nonlinear simulation, as predicted
  by the linear eigenmode analysis. We also see the high-latitude mode
  with m=1 in our nonlinear simulation but its amplitude is much weaker
  than that observed on the Sun.

Title: Small-scale dynamo in cool stars. I. Changes in stratification
    and near-surface convection for main-sequence spectral types
Authors: Bhatia, Tanayveer S.; Cameron, Robert H.; Solanki, Sami K.;
   Peter, Hardi; Przybylski, Damien; Witzke, Veronika; Shapiro, Alexander
Bibcode: 2022A&A...663A.166B
Altcode: 2022arXiv220600064B
  Context. Some of the small-scale solar magnetic flux can
  be attributed to a small-scale dynamo (SSD) operating in the
  near-surface convection. The SSD fields have consequences for
  solar granular convection, basal flux, and chromospheric heating. A
  similar SSD mechanism is expected to be active in the near-surface
  convection of other cool main-sequence stars, but this has not been
  investigated thus far. <BR /> Aims: We aim to investigate changes in
  stratification and convection due to inclusion of SSD fields for F3V,
  G2V, K0V, and M0V spectral types in the near-surface convection. <BR
  /> Methods: We studied 3D magnetohydrodynamic (MHD) models of the four
  stellar boxes, covering the subsurface convection zone up to the lower
  photosphere in a small Cartesian box, based on the MURaM radiative-MHD
  simulation code. We compared the SSD runs against reference hydrodynamic
  runs. <BR /> Results: The SSD is found to efficiently produce magnetic
  field with energies ranging between 5% to 80% of the plasma kinetic
  energy at different depths. This ratio tends to be larger for larger
  T<SUB>eff</SUB>. The relative change in density and gas pressure
  stratification for the deeper convective layers due to SSD magnetic
  fields is negligible, except for the F-star. For the F-star, there is
  a substantial reduction in convective velocities due to Lorentz force
  feedback from magnetic fields, which, in turn, reduces the turbulent
  pressure. <BR /> Conclusions: The SSD in near-surface convection for
  cool main-sequence stars introduces small but significant changes
  in thermodynamic stratification (especially for the F-star) due to a
  reduction in the convective velocities.

Title: Theory of solar oscillations in the inertial frequency range:
    Linear modes of the convection zone
Authors: Bekki, Yuto; Cameron, Robert H.; Gizon, Laurent
Bibcode: 2022A&A...662A..16B
Altcode: 2022arXiv220304442B
  Context. Several types of global-scale inertial modes of oscillation
  have been observed on the Sun. These include the equatorial Rossby
  modes, critical-latitude modes, and high-latitude modes. However,
  the columnar convective modes (predicted by simulations and also
  known as banana cells or thermal Rossby waves) remain elusive. <BR />
  Aims: We aim to investigate the influence of turbulent diffusivities,
  non-adiabatic stratification, differential rotation, and a latitudinal
  entropy gradient on the linear global modes of the rotating solar
  convection zone. <BR /> Methods: We numerically solved for the
  eigenmodes of a rotating compressible fluid inside a spherical
  shell. The model takes into account the solar stratification, turbulent
  diffusivities, differential rotation (determined by helioseismology),
  and the latitudinal entropy gradient. As a starting point, we restricted
  ourselves to a superadiabaticity and turbulent diffusivities that
  are uniform in space. We identified modes in the inertial frequency
  range, including the columnar convective modes as well as modes of
  a mixed character. The corresponding mode dispersion relations and
  eigenfunctions are computed for azimuthal orders of m ≤ 16. <BR />
  Results: The three main results are as follows. Firstly, we find
  that, for m ≳ 5, the radial dependence of the equatorial Rossby
  modes with no radial node (n = 0) is radically changed from the
  traditional expectation (r<SUP>m</SUP>) for turbulent diffusivities
  ≳10<SUP>12</SUP> cm<SUP>2</SUP> s<SUP>−1</SUP>. Secondly,
  we find mixed modes, namely, modes that share properties of the
  equatorial Rossby modes with one radial node (n = 1) and the columnar
  convective modes, which are not substantially affected by turbulent
  diffusion. Thirdly, we show that the m = 1 high-latitude mode in the
  model is consistent with the solar observations when the latitudinal
  entropy gradient corresponding to a thermal wind balance is included
  (baroclinically unstable mode). <BR /> Conclusions: To our knowledge,
  this work is the first realistic eigenvalue calculation of the global
  modes of the rotating solar convection zone. This calculation reveals
  a rich spectrum of modes in the inertial frequency range, which can
  be directly compared to the observations. In turn, the observed modes
  can inform us about the solar convection zone.

Title: The crucial role of surface magnetic fields for stellar
dynamos: ϵ Eridani, 61 Cygni A, and the Sun
Authors: Jeffers, S. V.; Cameron, R. H.; Marsden, S. C.; Boro Saikia,
   S.; Folsom, C. P.; Jardine, M. M.; Morin, J.; Petit, P.; See, V.;
   Vidotto, A. A.; Wolter, U.; Mittag, M.
Bibcode: 2022A&A...661A.152J
Altcode: 2022arXiv220107530J
  Cool main-sequence stars, such as the Sun, have magnetic fields which
  are generated by an internal dynamo mechanism. In the Sun, the dynamo
  mechanism produces a balance between the amounts of magnetic flux
  generated and lost over the Sun's 11-year activity cycle and it is
  visible in the Sun's different atmospheric layers using multi-wavelength
  observations. We used the same observational diagnostics, spanning
  several decades, to probe the emergence of magnetic flux on the two
  close by, active- and low-mass K dwarfs: 61 Cygni A and ϵ Eridani. Our
  results show that 61 Cygni A follows the Solar dynamo with a regular
  cycle at all wavelengths, while ϵ Eridani represents a more extreme
  level of the Solar dynamo, while also showing strong Solar-like
  characteristics. For the first time we show magnetic butterfly diagrams
  for stars other than the Sun. For the two K stars and the Sun, the rate
  at which the toroidal field is generated from surface poloidal field
  is similar to the rate at which toroidal flux is lost through flux
  emergence. This suggests that the surface field plays a crucial role in
  the dynamos of all three stars. Finally, for ϵ Eridani, we show that
  the two chromospheric cycle periods, of ∼3 and ∼13 years, correspond
  to two superimposed magnetic cycles. <P />The spectropolarimetic
  data are available from the Polarbase data archive: <A
  href="http://polarbase.irap.omp.eu/">http://polarbase.irap.omp.eu/</A>.

Title: Testing solar surface flux transport models in the first days
    after active region emergence
Authors: Gottschling, N.; Schunker, H.; Birch, A. C.; Cameron, R.;
   Gizon, L.
Bibcode: 2022A&A...660A...6G
Altcode: 2021arXiv211101896G
  Context. Active regions (ARs) play an important role in the magnetic
  dynamics of the Sun. Solar surface flux transport models (SFTMs) are
  used to describe the evolution of the radial magnetic field at the solar
  surface. The models are kinematic in the sense that the radial component
  of the magnetic field behaves as passively advected corks. There is,
  however, uncertainty about using these models in the early stage of
  AR evolution, where dynamic effects might be important. <BR /> Aims:
  We aim to test the applicability of SFTMs in the first days after the
  emergence of ARs by comparing them with observations. The models we
  employ range from passive evolution to models where the inflows around
  ARs are included. <BR /> Methods: We simulated the evolution of the
  surface magnetic field of 17 emerging ARs using a local surface flux
  transport simulation. The regions were selected such that they did not
  form fully fledged sunspots that exhibit moat flows. The simulation
  included diffusion and advection by a velocity field, for which we
  tested different models. For the flow fields, we used observed flows
  from local correlation tracking of solar granulation, as well as
  parametrizations of the inflows around ARs based on the gradient of
  the magnetic field. To evaluate our simulations, we measured the cross
  correlation between the observed and the simulated magnetic field, as
  well as the total unsigned flux of the ARs, over time. We also tested
  the validity of our simulations by varying the starting time relative
  to the emergence of flux. <BR /> Results: We find that the simulations
  using observed surface flows can reproduce the evolution of the observed
  magnetic flux. The effect of buffeting the field by supergranulation can
  be described as a diffusion process. The SFTM is applicable after 90%
  of the peak total unsigned flux of the AR has emerged. Diffusivities
  in the range between D = 250-720 km<SUP>2</SUP> s<SUP>−1</SUP> are
  consistent with the evolution of the AR flux in the first five days
  after this time. We find that the converging flows around emerging
  ARs are not important for the evolution of the total flux of the AR
  in these first five days; their effect of increasing flux cancellation
  is balanced by the decrease in flux transport away from the AR.

Title: A solar coronal loop in a box: Energy generation and heating
Authors: Breu, C.; Peter, H.; Cameron, R.; Solanki, S. K.; Przybylski,
   D.; Rempel, M.; Chitta, L. P.
Bibcode: 2022A&A...658A..45B
Altcode: 2021arXiv211211549B
  Context. Coronal loops are the basic building block of the upper solar
  atmosphere as seen in the extreme UV and X-rays. Comprehending how
  these are energized, structured, and evolve is key to understanding
  stellar coronae. <BR /> Aims: Here we investigate how the energy
  to heat the loop is generated by photospheric magneto-convection,
  transported into the upper atmosphere, and how the internal
  structure of a coronal magnetic loop forms. <BR /> Methods: In a 3D
  magnetohydrodynamics model, we study an isolated coronal loop rooted
  with both footpoints in a shallow layer within the convection zone
  using the MURaM code. To resolve its internal structure, we limited
  the computational domain to a rectangular box containing a single
  coronal loop as a straightened magnetic flux tube. Field-aligned heat
  conduction, gray radiative transfer in the photosphere and chromosphere,
  and optically thin radiative losses in the corona were taken into
  account. The footpoints were allowed to interact self-consistently
  with the granulation surrounding them. <BR /> Results: The loop is
  heated by a Poynting flux that is self-consistently generated through
  small-scale motions within individual magnetic concentrations in
  the photosphere. Turbulence develops in the upper layers of the
  atmosphere as a response to the footpoint motions. We see little
  sign of heating by large-scale braiding of magnetic flux tubes
  from different photospheric concentrations at a given footpoint. The
  synthesized emission, as it would be observed by the Atmospheric Imaging
  Assembly or the X-Ray Telescope, reveals transient bright strands that
  form in response to the heating events. Overall, our model roughly
  reproduces the properties and evolution of the plasma as observed
  within (the substructures of) coronal loops. <BR /> Conclusions:
  With this model we can build a coherent picture of how the energy
  flux to heat the upper atmosphere is generated near the solar surface
  and how this process drives and governs the heating and dynamics of
  a coronal loop. <P />Movie associated to Fig. 2 is available at <A
  href="https://www.aanda.org/10.1051/0004-6361/202141451/olm">https://www.aanda.org</A>

Title: On the size distribution of spots within sunspot groups
Authors: Mandal, Sudip; Krivova, Natalie A.; Cameron, Robert; Solanki,
   Sami K.
Bibcode: 2021A&A...652A...9M
Altcode: 2021arXiv210403534M
  The size distribution of sunspots provides key information about
  the generation and emergence processes of the solar magnetic
  field. Previous studies of size distribution have primarily focused
  on either the whole group or individual spot areas. In this paper we
  investigate the organisation of spot areas within sunspot groups. In
  particular, we analysed the ratio (R) of the area of the biggest spot
  (A<SUB>big_spot</SUB>) inside a group, to the total area of that group
  (A<SUB>group</SUB>). We used sunspot observations from Kislovodsk,
  Pulkovo, and Debrecen observatories, together covering solar cycles
  17-24. We find that at the time when the group area reaches its maximum,
  the single biggest spot in a group typically occupies about 60% of the
  group area. For half of all groups, R lies in the range between roughly
  50% and 70%. We also find R to change with A<SUB>group</SUB>, such that
  R reaches a maximum of about 0.65 for groups with A<SUB>group</SUB>
  ≈ 200 μHem and then remains at about 0.6 for larger groups. Our
  findings imply a scale-invariant emergence pattern, providing an
  observational constraint on the emergence process. Furthermore,
  extrapolation of our results to larger sunspot groups may have a
  bearing on the giant unresolved starspot features found in Doppler
  images of highly active Sun-like stars. Our results suggest that such
  giant features are composed of multiple spots, with the largest spot
  occupying roughly 55-75% of the total group area (i.e., the area of
  the giant starspots seen in Doppler images).

Title: Slow magneto-acoustic waves in simulations of a solar plage
    region carry enough energy to heat the chromosphere
Authors: Yadav, N.; Cameron, R. H.; Solanki, S. K.
Bibcode: 2021A&A...652A..43Y
Altcode: 2021arXiv210502932Y
  <BR /> Aims: We study the properties of slow magneto-acoustic waves
  that are naturally excited as a result of turbulent convection and we
  investigate their role in the energy balance of a plage region using
  three dimensional radiation magnetohydrodynamic simulations. <BR />
  Methods: To follow slow magneto-acoustic waves traveling along the
  magnetic field lines, we selected 25 seed locations inside a strong
  magnetic element and tracked the associated magnetic field lines both
  in space and time. We calculate the longitudinal component (i.e.,
  parallel to the field) of velocity at each grid point along the field
  line and compute the temporal power spectra at various heights above
  the mean solar surface. Additionally, the horizontally-averaged (over
  the whole domain) frequency power spectra for both longitudinal and
  vertical (i.e., the component perpendicular to the surface) components
  of velocity are calculated using time series at fixed locations. To
  compare our results with the observations, we degrade the simulation
  data with Gaussian kernels having a full width at half maxium of 100
  km and 200 km and calculate the horizontally-averaged power spectra
  for the vertical component of velocity using time series at fixed
  locations. <BR /> Results: The power spectra of the longitudinal
  component of velocity, averaged over 25 field lines in the core of
  a kG magnetic flux concentration reveal that the dominant period
  of oscillations shifts from ∼6.5 min in the photosphere to ∼4
  min in the chromosphere. This behavior is consistent with earlier
  studies that were restricted to vertically propagating waves. At the
  same time, the velocity power spectra, averaged horizontally over
  the whole domain, show that low frequency waves (∼6.5 min period)
  may reach well into the chromosphere. In addition, the power spectra
  at high frequencies follow a power law with an exponent close to
  −5/3, suggestive of turbulent excitation. Moreover, waves with
  frequencies above 5 mHz propagating along different field lines
  are found to be out of phase with each other, even within a single
  magnetic concentration. The horizontally-averaged power spectra of
  the vertical component of velocity at various effective resolutions
  show that the observed acoustic wave energy fluxes are underestimated
  by a factor of three, even if determined from observations carried
  out at a high spatial resolution of 200 km. Since the waves propagate
  along the non-vertical field lines, measuring the velocity component
  along the line-of-sight, rather than along the field, contributes
  significantly to this underestimation. Moreover, this underestimation of
  the energy flux indirectly indicates the importance of high-frequency
  waves that are shown to have a smaller spatial coherence and are thus
  more strongly influenced by the spatial averaging effect compared to
  low-frequency waves. <BR /> Conclusions: Inside a plage region, there
  is on average a significant fraction of low frequency waves leaking
  into the chromosphere due to inclined magnetic field lines. Our results
  show that longitudinal waves carry (just) enough energy to heat the
  chromosphere in the solar plage. However, phase differences between
  waves traveling along different field lines within a single magnetic
  concentration can lead to underestimations of the wave energy flux
  due to averaging effects in degraded simulation data and, similarly,
  in observations with lower spatial resolution. We find that current
  observations (with spatial resolution around 200 km) underestimate the
  energy flux by roughly a factor of three - or more if the observations
  are carried out at a lower spatial resolution. We expect that even
  at a very high resolution, which is expected with the next generation
  of telescopes such as DKIST and the EST, less than half, on average,
  of the energy flux carried by such waves will be detected if only the
  line-of-sight component of the velocity is measured.

Title: Solar inertial modes: Observations, identification, and
    diagnostic promise
Authors: Gizon, Laurent; Cameron, Robert H.; Bekki, Yuto; Birch,
   Aaron C.; Bogart, Richard S.; Brun, Allan Sacha; Damiani, Cilia;
   Fournier, Damien; Hyest, Laura; Jain, Kiran; Lekshmi, B.; Liang,
   Zhi-Chao; Proxauf, Bastian
Bibcode: 2021A&A...652L...6G
Altcode: 2021arXiv210709499G
  The oscillations of a slowly rotating star have long been classified
  into spheroidal and toroidal modes. The spheroidal modes include
  the well-known 5-min acoustic modes used in helioseismology. Here
  we report observations of the Sun's toroidal modes, for which the
  restoring force is the Coriolis force and whose periods are on the
  order of the solar rotation period. By comparing the observations
  with the normal modes of a differentially rotating spherical shell,
  we are able to identify many of the observed modes. These are the
  high-latitude inertial modes, the critical-latitude inertial modes,
  and the equatorial Rossby modes. In the model, the high-latitude
  and critical-latitude modes have maximum kinetic energy density at
  the base of the convection zone, and the high-latitude modes are
  baroclinically unstable due to the latitudinal entropy gradient. As
  a first application of inertial-mode helioseismology, we constrain
  the superadiabaticity and the turbulent viscosity in the deep
  convection zone. <P />Movie associated to Fig. 2 is available at <A
  href="https://www.aanda.org/10.1051/0004-6361/202141462/olm">https://www.aanda.org
  </A>

Title: A journey of exploration to the polar regions of a star:
    probing the solar poles and the heliosphere from high helio-latitude
Authors: Harra, Louise; Andretta, Vincenzo; Appourchaux, Thierry;
   Baudin, Frédéric; Bellot-Rubio, Luis; Birch, Aaron C.; Boumier,
   Patrick; Cameron, Robert H.; Carlsson, Matts; Corbard, Thierry;
   Davies, Jackie; Fazakerley, Andrew; Fineschi, Silvano; Finsterle,
   Wolfgang; Gizon, Laurent; Harrison, Richard; Hassler, Donald M.;
   Leibacher, John; Liewer, Paulett; Macdonald, Malcolm; Maksimovic,
   Milan; Murphy, Neil; Naletto, Giampiero; Nigro, Giuseppina; Owen,
   Christopher; Martínez-Pillet, Valentín; Rochus, Pierre; Romoli,
   Marco; Sekii, Takashi; Spadaro, Daniele; Veronig, Astrid; Schmutz, W.
Bibcode: 2021ExA...tmp...93H
Altcode: 2021arXiv210410876H
  A mission to view the solar poles from high helio-latitudes (above 60°)
  will build on the experience of Solar Orbiter as well as a long heritage
  of successful solar missions and instrumentation (e.g. SOHO Domingo et
  al. (Solar Phys. 162(1-2), 1-37 1995), STEREO Howard et al. (Space
  Sci. Rev. 136(1-4), 67-115 2008), Hinode Kosugi et al. (Solar
  Phys. 243(1), 3-17 2007), Pesnell et al. Solar Phys. 275(1-2),
  3-15 2012), but will focus for the first time on the solar poles,
  enabling scientific investigations that cannot be done by any other
  mission. One of the major mysteries of the Sun is the solar cycle. The
  activity cycle of the Sun drives the structure and behaviour of the
  heliosphere and of course, the driver of space weather. In addition,
  solar activity and variability provides fluctuating input into the
  Earth climate models, and these same physical processes are applicable
  to stellar systems hosting exoplanets. One of the main obstructions
  to understanding the solar cycle, and hence all solar activity,
  is our current lack of understanding of the polar regions. In this
  White Paper, submitted to the European Space Agency in response to the
  Voyage 2050 call, we describe a mission concept that aims to address
  this fundamental issue. In parallel, we recognise that viewing the Sun
  from above the polar regions enables further scientific advantages,
  beyond those related to the solar cycle, such as unique and powerful
  studies of coronal mass ejection processes, from a global perspective,
  and studies of coronal structure and activity in polar regions. Not
  only will these provide important scientific advances for fundamental
  stellar physics research, they will feed into our understanding of
  impacts on the Earth and other planets' space environment.

Title: Coronal loops in a box: 3D models of their internal structure,
    dynamics and heating
Authors: Breu, C. A.; Peter, H.; Cameron, R.; Solanki, S.; Przybylski,
   D.; Chitta, L.
Bibcode: 2021AAS...23810606B
Altcode:
  The corona of the Sun, and probably also of other stars, is built
  up by loops defined through the magnetic field. They vividly appear
  in solar observations in the extreme UV and X-rays. High-resolution
  observations show individual strands with diameters down to a few 100
  km, and so far it remains open what defines these strands, in particular
  their width, and where the energy to heat them is generated. <P />The
  aim of our study is to understand how the magnetic field couples the
  different layers of the solar atmosphere, how the energy generated
  by magnetoconvection is transported into the upper atmosphere and
  dissipated, and how this process determines the scales of observed
  bright strands in the loop. <P />To this end, we conduct 3D resistive
  MHD simulations with the MURaM code. We include the effects of heat
  conduction, radiative transfer and optically thin radiative losses.We
  study an isolated coronal loop that is rooted with both footpoints
  in a shallow convection zone layer. To properly resolve the internal
  structure of the loop while limiting the size of the computational box,
  the coronal loop is modelled as a straightened magnetic flux tube. By
  including part of the convection zone, we drive the evolution of
  the corona self-consistently by magnetoconvection. <P />We find that
  the energy injected into the loop is generated by internal coherent
  motions within strong magnetic elements. The resulting Poynting
  flux is channelled into the loop in vortex tubes forming a magnetic
  connection between the photosphere and corona, where it is dissipated
  and heats the upper atmosphere. <P />The coronal emission as it would
  be observed in solar extreme UV or X-ray observations, e.g. with AIA
  or XRT, shows transient bright strands.The widths of these strands are
  consistent with observations. From our model we find that the width
  of the strands is governed by the size of the individual photospheric
  magnetic field concentrations where the field line through these strands
  are rooted. Essentially, each coronal strand is rooted in a single
  magnetic patch in the photosphere, and the energy to heat the strand is
  generated by internal motions within this magnetic concentration. <P
  />With this model we can build a coherent picture of how energy and
  matter are transported into the upper solar atmosphere and how these
  processes structure the interior of coronal loops.

Title: Small-scale Dynamo in Cool Main-Sequence Stars: Effect on
    Stratification, Convection and Bolometric Intensity
Authors: Bhatia, T.; Cameron, R.; Solanki, S.; Peter, H.; Przybylski,
   D.; Witzke, V.; Shapiro, A.
Bibcode: 2021AAS...23830404B
Altcode:
  In cool main-sequence stars, the near-surface convection has an
  impact on the center-to-limb variation of photospheric emission, with
  implications for stellar lightcurves during planetary transits. In
  the Sun, there is strong evidence for a small-scale dynamo (SSD)
  maintaining the small-scale magnetic flux. This field could affect the
  near-surface convection in other cool main-sequence stars. <P />An SSD
  could conceivably generate equipartition magnetic fields, which could
  lead to non-negligible changes not only in convection and intensity
  characteristics, but also in stratification. We aim to investigate these
  changes for F, G, K and M stars. 3D MHD models of the four stellar types
  covering the subsurface region to lower atmosphere in a small cartesian
  box are studied using the MURaM rMHD simulation code. The MHD runs are
  compared against a reference hydrodynamic (HD) run. <P />The deviations
  in stratification for the deeper convective layers is negligible,
  except for the F-star, where reduction in turbulent pressure due to
  magnetic fields is substantial. Convective velocities are reduced
  by a similar percentage for all the cases due to inhibitory effect
  of strong magnetic fields near the bottom boundary. All four cases
  show small-scale brightenings in intergranular lanes, corresponding
  to magnetic field concentrations, but overall effects on the r.m.s
  contrast and spatial powerspectra are varied.

Title: First Results of the Chromospheric MURaM code
Authors: Przybylski, D. F.; Cameron, R.; Solanki, S.; Rempel, M.
Bibcode: 2021AAS...23810605P
Altcode:
  The solar chromosphere, spanning the region between the photosphere
  and the transition to the corona, remains one of the least understood
  parts of the Sun. This is partly because observing the chromosphere
  and interpreting these observations is full of pitfalls. Also, the
  simulation of the chromosphere is complex, as the particle densities
  and collisional rates are too low to maintain local thermodynamic
  equilibrium (LTE). Additionally, the recombination rates of hydrogen are
  larger than the dynamical timescales and the populations must be solved
  in non-equilibrium (NE). Realistic simulations of the chromosphere
  must treat the magneto-hydrodynamics, time-dependant atomic and
  molecular chemistry, and radiation transfer simultaneously. <P />The
  MURaM radiation-MHD code has previously been used for investigation
  of the connection between the solar photosphere and corona, ranging
  from small-scale dynamo generated 'quiet' sun fields to sunspots and
  complex active regions. Until now these simulations have been performed
  in LTE, greatly limiting their realism in the solar chromosphere. We
  have extended MURaM to include NLTE effects following the prescriptions
  used in the Bifrost code. The low viscocity and resistivity of the MURaM
  code leads to turbulent convection in the photosphere with kilo-Gauss
  mixed-polarity magnetic fields. This results in a dynamic chromosphere
  with strong shocks and a finely structured magnetic field. We discuss
  the implications of this new model towards observations of chromospheric
  spectral lines.

Title: Modelling the evolution of the Sun's open and total magnetic
    flux
Authors: Krivova, N. A.; Solanki, S. K.; Hofer, B.; Wu, C. -J.;
   Usoskin, I. G.; Cameron, R.
Bibcode: 2021A&A...650A..70K
Altcode: 2021arXiv210315603K
  Solar activity in all its varied manifestations is driven by the
  magnetic field. Two global quantities are particularly important for
  many purposes, the Sun's total and open magnetic flux, which can be
  computed from sunspot number records using models. Such sunspot-driven
  models, however, do not take into account the presence of magnetic
  flux during grand minima, such as the Maunder minimum. Here we
  present a major update of a widely used simple model, which now takes
  into account the observation that the distribution of all magnetic
  features on the Sun follows a single power law. The exponent of the
  power law changes over the solar cycle. This allows for the emergence
  of small-scale magnetic flux even when no sunspots have been present
  for multiple decades and leads to non-zero total and open magnetic
  flux also in the deepest grand minima, such as the Maunder minimum,
  thus overcoming a major shortcoming of the earlier models. The results
  of the updated model compare well with the available observations and
  reconstructions of the solar total and open magnetic flux. This opens
  up the possibility of improved reconstructions of the sunspot number
  from time series of the cosmogenic isotope production rate.

Title: Nonequilibrium Equation of State in Stellar Atmospheres
Authors: Anusha, L. S.; van Noort, M.; Cameron, R. H.
Bibcode: 2021ApJ...911...71A
Altcode: 2021arXiv210413650A
  In the stellar chromospheres, radiative energy transport is dominated by
  only the strongest spectral lines. For these lines, the approximation of
  local thermodynamic equilibrium (LTE) is known to be very inaccurate,
  and a state of equilibrium cannot be assumed in general. To calculate
  the radiative energy transport under these conditions, the population
  evolution equation must be evaluated explicitly, including all
  time-dependent terms. We develop a numerical method to solve the
  evolution equation for the atomic-level populations in a time-implicit
  way, keeping all time-dependent terms to first order. We show that
  the linear approximation of the time dependence of the populations
  can handle very large time steps without losing accuracy. We
  reproduce the benchmark solutions from earlier, well-established
  works in terms of non-LTE kinetic equilibrium solutions and typical
  ionization/recombination timescales in the solar chromosphere.

Title: Small-scale dynamo in an F-star: effects on near-surface
    stratification, convection and intensity
Authors: Bhatia, Tanayveer; Cameron, Robert; Solanki, Sami; Peter,
   Hardi; Przybylski, Damien; Witzke, Veronika; Shapiro, Alexander
Bibcode: 2021csss.confE..75B
Altcode:
  The emission from the photosphere of stars shows a systematic
  center-to-limb variation. In cool main-sequence stars, the near-surface
  convection has an impact on this variation, with implications for
  lightcurves of stars during planetary transits. In the Sun, there
  is strong evidence for a small-scale dynamo (SSD) maintaining the
  small-scale magnetic flux. We aim to investigate what additional
  effects such a field would play for other cool main-sequence
  stars. In our work we first concentrate on F-stars. This is because
  they have sonic velocities near the surface, implying a rough
  equipartition between internal and kinetic energies. In addition,
  an SSD might create a significant magnetic energy density to impact
  the results. We investigate the interplay between internal, kinetic
  and magnetic energies in 3D cartesian box MHD models of a F3V-star in
  the near-surface convection, using the MURaM radiative-MHD simulation
  code. Along with a reference hydrodynamic run, two MHD models with
  self-consistently generated magnetic fields with two different lower
  boundary conditions are considered. We find that the SSD process
  creates a magnetic field with energy within an order of magnitude of the
  internal and the kinetic energy. Compared to the hydrodynamic run, we
  find slight (~1-3%) but significant deviations in density, gas pressure
  and temperature stratification. At the surface, this corresponds to a
  temperature difference of ~130 K. As expected, there is a significant
  reduction in kinetic energy flux once the SSD is operational. The
  changes in intensity are more subtle, both in total intensity and
  granulation pattern. From this we conclude that the presence of an
  SSD will have a significant impact on the atmospheric structure and
  intensity characteristics seen at the surface. This makes it clear
  that it would be important to consider the spatially and temporally
  averaged effects of the SSD also for global stellar models.

Title: Sunspot Simulations: Penumbra Formation and the Fluting
    Instability
Authors: Panja, Mayukh; Cameron, Robert H.; Solanki, Sami K.
Bibcode: 2021ApJ...907..102P
Altcode: 2020arXiv201111447P
  The fluting instability has been suggested as the driver of the
  subsurface structure of sunspot flux tubes. We conducted a series
  of numerical experiments where we used flux tubes with different
  initial curvatures to study the effect of the fluting instability on
  the subsurface structure of spots. We used the MURaM code, which has
  previously been used to simulate complete sunspots, to first compute
  four sunspots in the slab geometry and then two complete circular
  spots of opposite polarities. We find that the curvature of a flux tube
  indeed determines the degree of fluting the flux tube will undergo—the
  more curved a flux tube is, the more fluted it becomes. In addition,
  sunspots with strong curvature have strong horizontal fields at the
  surface and therefore readily form penumbral filaments. The fluted
  sunspots eventually break up from below, with lightbridges appearing
  at the surface several hours after fluting commences.

Title: Sensitivity of the Cherenkov Telescope Array for probing
    cosmology and fundamental physics with gamma-ray propagation
Authors: Abdalla, H.; Abe, H.; Acero, F.; Acharyya, A.; Adam, R.;
   Agudo, I.; Aguirre-Santaella, A.; Alfaro, R.; Alfaro, J.; Alispach,
   C.; Aloisio, R.; Alves Batista, R.; Amati, L.; Amato, E.; Ambrosi, G.;
   Angüner, E. O.; Araudo, A.; Armstrong, T.; Arqueros, F.; Arrabito,
   L.; Asano, K.; Ascasíbar, Y.; Ashley, M.; Backes, M.; Balazs, C.;
   Balbo, M.; Balmaverde, B.; Baquero Larriva, A.; Barbosa Martins, V.;
   Barkov, M.; Baroncelli, L.; Barres de Almeida, U.; Barrio, J. A.;
   Batista, P. -I.; Becerra González, J.; Becherini, Y.; Beck, G.;
   Becker Tjus, J.; Belmont, R.; Benbow, W.; Bernardini, E.; Berti, A.;
   Berton, M.; Bertucci, B.; Beshley, V.; Bi, B.; Biasuzzi, B.; Biland,
   A.; Bissaldi, E.; Biteau, J.; Blanch, O.; Bocchino, F.; Boisson,
   C.; Bolmont, J.; Bonanno, G.; Bonneau Arbeletche, L.; Bonnoli, G.;
   Bordas, P.; Bottacini, E.; Böttcher, M.; Bozhilov, V.; Bregeon,
   J.; Brill, A.; Brown, A. M.; Bruno, P.; Bruno, A.; Bulgarelli, A.;
   Burton, M.; Buscemi, M.; Caccianiga, A.; Cameron, R.; Capasso, M.;
   Caprai, M.; Caproni, A.; Capuzzo-Dolcetta, R.; Caraveo, P.; Carosi, R.;
   Carosi, A.; Casanova, S.; Cascone, E.; Cauz, D.; Cerny, K.; Cerruti,
   M.; Chadwick, P.; Chaty, S.; Chen, A.; Chernyakova, M.; Chiaro, G.;
   Chiavassa, A.; Chytka, L.; Conforti, V.; Conte, F.; Contreras, J. L.;
   Coronado-Blazquez, J.; Cortina, J.; Costa, A.; Costantini, H.; Covino,
   S.; Cristofari, P.; Cuevas, O.; D'Ammando, F.; Daniel, M. K.; Davies,
   J.; Dazzi, F.; De Angelis, A.; de Bony de Lavergne, M.; De Caprio, V.;
   de Cássia dos Anjos, R.; de Gouveia Dal Pino, E. M.; De Lotto, B.;
   De Martino, D.; de Naurois, M.; de Oña Wilhelmi, E.; De Palma, F.;
   de Souza, V.; Delgado, C.; Della Ceca, R.; della Volpe, D.; Depaoli,
   D.; Di Girolamo, T.; Di Pierro, F.; Díaz, C.; Díaz-Bahamondes,
   C.; Diebold, S.; Djannati-Ataï, A.; Dmytriiev, A.; Domínguez, A.;
   Donini, A.; Dorner, D.; Doro, M.; Dournaux, J.; Dwarkadas, V. V.;
   Ebr, J.; Eckner, C.; Einecke, S.; Ekoume, T. R. N.; Elsässer, D.;
   Emery, G.; Evoli, C.; Fairbairn, M.; Falceta-Goncalves, D.; Fegan,
   S.; Feng, Q.; Ferrand, G.; Fiandrini, E.; Fiasson, A.; Fioretti, V.;
   Foffano, L.; Fonseca, M. V.; Font, L.; Fontaine, G.; Franco, F. J.;
   Freixas Coromina, L.; Fukami, S.; Fukazawa, Y.; Fukui, Y.; Gaggero,
   D.; Galanti, G.; Gammaldi, V.; Garcia, E.; Garczarczyk, M.; Gascon,
   D.; Gaug, M.; Gent, A.; Ghalumyan, A.; Ghirlanda, G.; Gianotti, F.;
   Giarrusso, M.; Giavitto, G.; Giglietto, N.; Giordano, F.; Glicenstein,
   J.; Goldoni, P.; González, J. M.; Gourgouliatos, K.; Grabarczyk, T.;
   Grandi, P.; Granot, J.; Grasso, D.; Green, J.; Grube, J.; Gueta, O.;
   Gunji, S.; Halim, A.; Harvey, M.; Hassan Collado, T.; Hayashi, K.;
   Heller, M.; Hernández Cadena, S.; Hervet, O.; Hinton, J.; Hiroshima,
   N.; Hnatyk, B.; Hnatyk, R.; Hoffmann, D.; Hofmann, W.; Holder, J.;
   Horan, D.; Hörandel, J.; Horvath, P.; Hovatta, T.; Hrabovsky, M.;
   Hrupec, D.; Hughes, G.; Hütten, M.; Iarlori, M.; Inada, T.; Inoue,
   S.; Insolia, A.; Ionica, M.; Iori, M.; Jacquemont, M.; Jamrozy,
   M.; Janecek, P.; Jiménez Martínez, I.; Jin, W.; Jung-Richardt,
   I.; Jurysek, J.; Kaaret, P.; Karas, V.; Karkar, S.; Kawanaka, N.;
   Kerszberg, D.; Khélifi, B.; Kissmann, R.; Knödlseder, J.; Kobayashi,
   Y.; Kohri, K.; Komin, N.; Kong, A.; Kosack, K.; Kubo, H.; La Palombara,
   N.; Lamanna, G.; Lang, R. G.; Lapington, J.; Laporte, P.; Lefaucheur,
   J.; Lemoine-Goumard, M.; Lenain, J.; Leone, F.; Leto, G.; Leuschner,
   F.; Lindfors, E.; Lloyd, S.; Lohse, T.; Lombardi, S.; Longo, F.;
   Lopez, A.; López, M.; López-Coto, R.; Loporchio, S.; Lucarelli, F.;
   Luque-Escamilla, P. L.; Lyard, E.; Maggio, C.; Majczyna, A.; Makariev,
   M.; Mallamaci, M.; Mandat, D.; Maneva, G.; Manganaro, M.; Manicò,
   G.; Marcowith, A.; Marculewicz, M.; Markoff, S.; Marquez, P.; Martí,
   J.; Martinez, O.; Martínez, M.; Martínez, G.; Martínez-Huerta, H.;
   Maurin, G.; Mazin, D.; Mbarubucyeye, J. D.; Medina Miranda, D.; Meyer,
   M.; Micanovic, S.; Miener, T.; Minev, M.; Miranda, J. M.; Mitchell,
   A.; Mizuno, T.; Mode, B.; Moderski, R.; Mohrmann, L.; Molina, E.;
   Montaruli, T.; Moralejo, A.; Morales Merino, J.; Morcuende-Parrilla,
   D.; Morselli, A.; Mukherjee, R.; Mundell, C.; Murach, T.; Muraishi, H.;
   Nagai, A.; Nakamori, T.; Nemmen, R.; Niemiec, J.; Nieto, D.; Nievas,
   M.; Nikolajuk, M.; Nishijima, K.; Noda, K.; Nosek, D.; Nozaki, S.;
   O'Brien, P.; Ohira, Y.; Ohishi, M.; Oka, T.; Ong, R. A.; Orienti,
   M.; Orito, R.; Orlandini, M.; Orlando, E.; Osborne, J. P.; Ostrowski,
   M.; Oya, I.; Pagliaro, A.; Palatka, M.; Paneque, D.; Pantaleo, F. R.;
   Paredes, J. M.; Parmiggiani, N.; Patricelli, B.; Pavletić, L.; Pe'er,
   A.; Pech, M.; Pecimotika, M.; Peresano, M.; Persic, M.; Petruk, O.;
   Pfrang, K.; Piatteli, P.; Pietropaolo, E.; Pillera, R.; Pilszyk, B.;
   Pimentel, D.; Pintore, F.; Pita, S.; Pohl, M.; Poireau, V.; Polo,
   M.; Prado, R. R.; Prast, J.; Principe, G.; Produit, N.; Prokoph,
   H.; Prouza, M.; Przybilski, H.; Pueschel, E.; Pühlhofer, G.; Pumo,
   M. L.; Punch, M.; Queiroz, F.; Quirrenbach, A.; Rando, R.; Razzaque,
   S.; Rebert, E.; Recchia, S.; Reichherzer, P.; Reimer, O.; Reimer,
   A.; Renier, Y.; Reposeur, T.; Rhode, W.; Ribeiro, D.; Ribó, M.;
   Richtler, T.; Rico, J.; Rieger, F.; Rizi, V.; Rodriguez, J.; Rodriguez
   Fernandez, G.; Rodriguez Ramirez, J. C.; Rodríguez Vázquez, J. J.;
   Romano, P.; Romeo, G.; Roncadelli, M.; Rosado, J.; Rosales de Leon,
   A.; Rowell, G.; Rudak, B.; Rujopakarn, W.; Russo, F.; Sadeh, I.;
   Saha, L.; Saito, T.; Salesa Greus, F.; Sanchez, D.; Sánchez-Conde,
   M.; Sangiorgi, P.; Sano, H.; Santander, M.; Santos, E. M.; Sanuy, A.;
   Sarkar, S.; Saturni, F. G.; Sawangwit, U.; Scherer, A.; Schleicher,
   B.; Schovanek, P.; Schussler, F.; Schwanke, U.; Sciacca, E.; Scuderi,
   S.; Seglar Arroyo, M.; Sergijenko, O.; Servillat, M.; Seweryn, K.;
   Shalchi, A.; Sharma, P.; Shellard, R. C.; Siejkowski, H.; Sinha, A.;
   Sliusar, V.; Slowikowska, A.; Sokolenko, A.; Sol, H.; Specovius, A.;
   Spencer, S.; Spiga, D.; Stamerra, A.; Stanič, S.; Starling, R.;
   Stolarczyk, T.; Straumann, U.; Strišković, J.; Suda, Y.; Świerk,
   P.; Tagliaferri, G.; Takahashi, H.; Takahashi, M.; Tavecchio, F.;
   Taylor, L.; Tejedor, L. A.; Temnikov, P.; Terrier, R.; Terzic, T.;
   Testa, V.; Tian, W.; Tibaldo, L.; Tonev, D.; Torres, D. F.; Torresi,
   E.; Tosti, L.; Tothill, N.; Tovmassian, G.; Travnicek, P.; Truzzi,
   S.; Tuossenel, F.; Umana, G.; Vacula, M.; Vagelli, V.; Valentino, M.;
   Vallage, B.; Vallania, P.; van Eldik, C.; Varner, G. S.; Vassiliev, V.;
   Vázquez Acosta, M.; Vecchi, M.; Veh, J.; Vercellone, S.; Vergani, S.;
   Verguilov, V.; Vettolani, G. P.; Viana, A.; Vigorito, C. F.; Vitale,
   V.; Vorobiov, S.; Vovk, I.; Vuillaume, T.; Wagner, S. J.; Walter,
   R.; Watson, J.; White, M.; White, R.; Wiemann, R.; Wierzcholska, A.;
   Will, M.; Williams, D. A.; Wischnewski, R.; Wolter, A.; Yamazaki, R.;
   Yanagita, S.; Yang, L.; Yoshikoshi, T.; Zacharias, M.; Zaharijas, G.;
   Zaric, D.; Zavrtanik, M.; Zavrtanik, D.; Zdziarski, A. A.; Zech, A.;
   Zechlin, H.; Zhdanov, V. I.; Živec, M.
Bibcode: 2021JCAP...02..048A
Altcode: 2020arXiv201001349C
  The Cherenkov Telescope Array (CTA), the new-generation ground-based
  observatory for γ astronomy, provides unique capabilities to address
  significant open questions in astrophysics, cosmology, and fundamental
  physics. We study some of the salient areas of γ cosmology that can be
  explored as part of the Key Science Projects of CTA, through simulated
  observations of active galactic nuclei (AGN) and of their relativistic
  jets. Observations of AGN with CTA will enable a measurement of γ
  absorption on the extragalactic background light with a statistical
  uncertainty below 15% up to a redshift z=2 and to constrain or detect
  γ halos up to intergalactic-magnetic-field strengths of at least 0.3
  pG . Extragalactic observations with CTA also show promising potential
  to probe physics beyond the Standard Model. The best limits on Lorentz
  invariance violation from γ astronomy will be improved by a factor
  of at least two to three. CTA will also probe the parameter space in
  which axion-like particles could constitute a significant fraction, if
  not all, of dark matter. We conclude on the synergies between CTA and
  other upcoming facilities that will foster the growth of γ cosmology.

Title: The solar dynamo and flux emergence
Authors: Cameron, Robert
Bibcode: 2021cosp...43E1728C
Altcode:
  Magnetic flux generated by dynamo action in the solar convection
  zone is carried by flows from the solar convection zone, through the
  photosphere, into the chromosphere and corona. During the emergence
  process a rising magnetic flux loop is given both a random and
  systematic tilt with respect to the east-west direction. This rise
  through the photosphere is called flux emergence, and it plays an
  essential role in the Babcock-Leighton model of the solar dynamo. In
  this talke we will consider the flows which are responsible for
  flux emergence. We will then show how the emerged field reverses
  the polar fields and creates new flux to emerge during the next
  cycle. Quantitative estimates will be made for the different terms
  involved in the subsurface magnetic flux budget.

Title: Vortex flow properties in simulations of solar plage region:
    Evidence for their role in chromospheric heating
Authors: Yadav, N.; Cameron, R. H.; Solanki, S. K.
Bibcode: 2021A&A...645A...3Y
Altcode: 2020arXiv201014971Y
  Context. Vortex flows exist across a broad range of spatial and
  temporal scales in the solar atmosphere. Small-scale vortices are
  thought to play an important role in energy transport in the solar
  atmosphere. However, their physical properties remain poorly understood
  due to the limited spatial resolution of the observations. <BR />
  Aims: We explore and analyze the physical properties of small-scale
  vortices inside magnetic flux tubes using numerical simulations, and
  investigate whether they contribute to heating the chromosphere in a
  plage region. <BR /> Methods: Using the three-dimensional radiative
  magnetohydrodynamic simulation code MURaM, we perform numerical
  simulations of a unipolar solar plage region. To detect and isolate
  vortices we use the swirling strength criterion and select the locations
  where the fluid is rotating with an angular velocity greater than
  a certain threshold. We concentrate on small-scale vortices as they
  are the strongest and carry most of the energy. We explore the spatial
  profiles of physical quantities such as density and horizontal velocity
  inside these vortices. Moreover, to learn their general characteristics,
  a statistical investigation is performed. <BR /> Results: Magnetic
  flux tubes have a complex filamentary substructure harboring an
  abundance of small-scale vortices. At the interfaces between vortices
  strong current sheets are formed that may dissipate and heat the solar
  chromosphere. Statistically, vortices have higher densities and higher
  temperatures than the average values at the same geometrical height
  in the chromosphere. <BR /> Conclusions: We conclude that small-scale
  vortices are ubiquitous in solar plage regions; they are denser and
  hotter structures that contribute to chromospheric heating, possibly
  by dissipation of the current sheets formed at their interfaces.

Title: Non-equilibrium equation-of-state in stellar atmospheres
Authors: Lokanathapura Seetharamabhasari, Anusha; Cameron, Robert;
   Van Noort, Michiel
Bibcode: 2021cosp...43E.985L
Altcode:
  In the stellar atmospheres, radiative energy transport is dominated by
  only the strongest spectral lines. For these lines, the approximation of
  local thermo-dynamic equilibrium (LTE) is known to be very inaccurate,
  and a state of equilibrium cannot be assumed in general. Therefore to
  understand the structure and dynamics of stellar atmospheres through
  evolving magneto-hydro-dynamic equations, one needs a non-equilibrium
  equation of state. To calculate the radiative energy transport under
  these conditions, the population evolution equation must be evaluated
  including all time dependent terms. To this end, we have developed a new
  numerical method to solve the non-LTE non-equilibrium radiative transfer
  problem. We solve evolution equation for the atomic level populations
  in a time-implicit way, keeping all time dependent terms to first
  order. We have tested our method by reproducing earlier works, namely,
  a) determining chromosperic time-scales of ionization/recombination,
  b) showing that our non-equilibrium solver evolves to the statistical
  equilibrium solution obtained from an independent non-LTE spectral
  synthesis code. In this presentation, I will describe the method,
  and discuss equilibrium solutions.

Title: Sensitivity of the Cherenkov Telescope Array to a dark matter
    signal from the Galactic centre
Authors: Acharyya, A.; Adam, R.; Adams, C.; Agudo, I.;
   Aguirre-Santaella, A.; Alfaro, R.; Alfaro, J.; Alispach, C.; Aloisio,
   R.; Alves Batista, R.; Amati, L.; Ambrosi, G.; Angüner, E. O.;
   Antonelli, L. A.; Aramo, C.; Araudo, A.; Armstrong, T.; Arqueros,
   F.; Asano, K.; Ascasíbar, Y.; Ashley, M.; Balazs, C.; Ballester,
   O.; Baquero Larriva, A.; Barbosa Martins, V.; Barkov, M.; Barres
   de Almeida, U.; Barrio, J. A.; Bastieri, D.; Becerra, J.; Beck, G.;
   Becker Tjus, J.; Benbow, W.; Benito, M.; Berge, D.; Bernardini, E.;
   Bernlöhr, K.; Berti, A.; Bertucci, B.; Beshley, V.; Biasuzzi, B.;
   Biland, A.; Bissaldi, E.; Biteau, J.; Blanch, O.; Blazek, J.; Bocchino,
   F.; Boisson, C.; Bonneau Arbeletche, L.; Bordas, P.; Bosnjak, Z.;
   Bottacini, E.; Bozhilov, V.; Bregeon, J.; Brill, A.; Bringmann, T.;
   Brown, A. M.; Brun, P.; Brun, F.; Bruno, P.; Bulgarelli, A.; Burton,
   M.; Burtovoi, A.; Buscemi, M.; Cameron, R.; Capasso, M.; Caproni, A.;
   Capuzzo-Dolcetta, R.; Caraveo, P.; Carosi, R.; Carosi, A.; Casanova,
   S.; Cascone, E.; Cassol, F.; Catalani, F.; Cauz, D.; Cerruti, M.;
   Chadwick, P.; Chaty, S.; Chen, A.; Chernyakova, M.; Chiaro, G.;
   Chiavassa, A.; Chikawa, M.; Chudoba, J.; Çolak, M.; Conforti, V.;
   Coniglione, R.; Conte, F.; Contreras, J. L.; Coronado-Blazquez, J.;
   Costa, A.; Costantini, H.; Cotter, G.; Cristofari, P.; D'Aimath, A.;
   D'Ammando, F.; Damone, L. A.; Daniel, M. K.; Dazzi, F.; De Angelis,
   A.; De Caprio, V.; de Cássia dos Anjos, R.; de Gouveia Dal Pino,
   E. M.; De Lotto, B.; De Martino, D.; de Oña Wilhelmi, E.; De Palma,
   F.; de Souza, V.; Delgado, C.; Delgado Giler, A. G.; della Volpe,
   D.; Depaoli, D.; Di Girolamo, T.; Di Pierro, F.; Di Venere, L.;
   Diebold, S.; Dmytriiev, A.; Domínguez, A.; Donini, A.; Doro, M.;
   Ebr, J.; Eckner, C.; Edwards, T. D. P.; Ekoume, T. R. N.; Elsässer,
   D.; Evoli, C.; Falceta-Goncalves, D.; Fedorova, E.; Fegan, S.;
   Feng, Q.; Ferrand, G.; Ferrara, G.; Fiandrini, E.; Fiasson, A.;
   Filipovic, M.; Fioretti, V.; Fiori, M.; Foffano, L.; Fontaine, G.;
   Fornieri, O.; Franco, F. J.; Fukami, S.; Fukui, Y.; Gaggero, D.;
   Galaz, G.; Gammaldi, V.; Garcia, E.; Garczarczyk, M.; Gascon, D.;
   Gent, A.; Ghalumyan, A.; Gianotti, F.; Giarrusso, M.; Giavitto, G.;
   Giglietto, N.; Giordano, F.; Giuliani, A.; Glicenstein, J.; Gnatyk,
   R.; Goldoni, P.; González, M. M.; Gourgouliatos, K.; Granot, J.;
   Grasso, D.; Green, J.; Grillo, A.; Gueta, O.; Gunji, S.; Halim, A.;
   Hassan, T.; Heller, M.; Hernández Cadena, S.; Hiroshima, N.; Hnatyk,
   B.; Hofmann, W.; Holder, J.; Horan, D.; Hörandel, J.; Horvath, P.;
   Hovatta, T.; Hrabovsky, M.; Hrupec, D.; Hughes, G.; Humensky, T. B.;
   Hütten, M.; Iarlori, M.; Inada, T.; Inoue, S.; Iocco, F.; Iori, M.;
   Jamrozy, M.; Janecek, P.; Jin, W.; Jouvin, L.; Jurysek, J.; Karukes,
   E.; Katarzyński, K.; Kazanas, D.; Kerszberg, D.; Kherlakian, M. C.;
   Kissmann, R.; Knödlseder, J.; Kobayashi, Y.; Kohri, K.; Komin,
   N.; Kubo, H.; Kushida, J.; Lamanna, G.; Lapington, J.; Laporte,
   P.; Leigui de Oliveira, M. A.; Lenain, J.; Leone, F.; Leto, G.;
   Lindfors, E.; Lohse, T.; Lombardi, S.; Longo, F.; Lopez, A.; López,
   M.; López-Coto, R.; Loporchio, S.; Luque-Escamilla, P. L.; Mach,
   E.; Maggio, C.; Maier, G.; Mallamaci, M.; Malta Nunes de Almeida,
   R.; Mandat, D.; Manganaro, M.; Mangano, S.; Manicò, G.; Marculewicz,
   M.; Mariotti, M.; Markoff, S.; Marquez, P.; Martí, J.; Martinez, O.;
   Martínez, M.; Martínez, G.; Martínez-Huerta, H.; Maurin, G.; Mazin,
   D.; Mbarubucyeye, J. D.; Medina Miranda, D.; Meyer, M.; Miceli, M.;
   Miener, T.; Minev, M.; Miranda, J. M.; Mirzoyan, R.; Mizuno, T.;
   Mode, B.; Moderski, R.; Mohrmann, L.; Molina, E.; Montaruli, T.;
   Moralejo, A.; Morcuende-Parrilla, D.; Morselli, A.; Mukherjee, R.;
   Mundell, C.; Nagai, A.; Nakamori, T.; Nemmen, R.; Niemiec, J.; Nieto,
   D.; Nikołajuk, M.; Ninci, D.; Noda, K.; Nosek, D.; Nozaki, S.; Ohira,
   Y.; Ohishi, M.; Ohtani, Y.; Oka, T.; Okumura, A.; Ong, R. A.; Orienti,
   M.; Orito, R.; Orlandini, M.; Orlando, S.; Orlando, E.; Ostrowski,
   M.; Oya, I.; Pagano, I.; Pagliaro, A.; Palatiello, M.; Pantaleo,
   F. R.; Paredes, J. M.; Pareschi, G.; Parmiggiani, N.; Patricelli, B.;
   Pavletić, L.; Pe'er, A.; Pecimotika, M.; Pérez-Romero, J.; Persic,
   M.; Petruk, O.; Pfrang, K.; Piano, G.; Piatteli, P.; Pietropaolo,
   E.; Pillera, R.; Pilszyk, B.; Pintore, F.; Pohl, M.; Poireau, V.;
   Prado, R. R.; Prandini, E.; Prast, J.; Principe, G.; Prokoph, H.;
   Prouza, M.; Przybilski, H.; Pühlhofer, G.; Pumo, M. L.; Queiroz,
   F.; Quirrenbach, A.; Rainò, S.; Rando, R.; Razzaque, S.; Recchia,
   S.; Reimer, O.; Reisenegger, A.; Renier, Y.; Rhode, W.; Ribeiro, D.;
   Ribó, M.; Richtler, T.; Rico, J.; Rieger, F.; Rinchiuso, L.; Rizi,
   V.; Rodriguez, J.; Rodriguez Fernandez, G.; Rodriguez Ramirez, J. C.;
   Rojas, G.; Romano, P.; Romeo, G.; Rosado, J.; Rowell, G.; Rudak,
   B.; Russo, F.; Sadeh, I.; Sæther Hatlen, E.; Safi-Harb, S.; Salesa
   Greus, F.; Salina, G.; Sanchez, D.; Sánchez-Conde, M.; Sangiorgi, P.;
   Sano, H.; Santander, M.; Santos, E. M.; Santos-Lima, R.; Sanuy, A.;
   Sarkar, S.; Saturni, F. G.; Sawangwit, U.; Schussler, F.; Schwanke,
   U.; Sciacca, E.; Scuderi, S.; Seglar-Arroyo, M.; Sergijenko, O.;
   Servillat, M.; Seweryn, K.; Shalchi, A.; Sharma, P.; Shellard, R. C.;
   Siejkowski, H.; Silk, J.; Siqueira, C.; Sliusar, V.; Słowikowska,
   A.; Sokolenko, A.; Sol, H.; Spencer, S.; Stamerra, A.; Stanič, S.;
   Starling, R.; Stolarczyk, T.; Straumann, U.; Strišković, J.; Suda,
   Y.; Suomijarvi, T.; Świerk, P.; Tavecchio, F.; Taylor, L.; Tejedor,
   L. A.; Teshima, M.; Testa, V.; Tibaldo, L.; Todero Peixoto, C. J.;
   Tokanai, F.; Tonev, D.; Tosti, G.; Tosti, L.; Tothill, N.; Truzzi,
   S.; Travnicek, P.; Vagelli, V.; Vallage, B.; Vallania, P.; van Eldik,
   C.; Vandenbroucke, J.; Varner, G. S.; Vassiliev, V.; Vázquez Acosta,
   M.; Vecchi, M.; Ventura, S.; Vercellone, S.; Vergani, S.; Verna, G.;
   Viana, A.; Vigorito, C. F.; Vink, J.; Vitale, V.; Vorobiov, S.; Vovk,
   I.; Vuillaume, T.; Wagner, S. J.; Walter, R.; Watson, J.; Weniger,
   C.; White, R.; White, M.; Wiemann, R.; Wierzcholska, A.; Will, M.;
   Williams, D. A.; Wischnewski, R.; Yanagita, S.; Yang, L.; Yoshikoshi,
   T.; Zacharias, M.; Zaharijas, G.; Zakaria, A. A.; Zampieri, L.; Zanin,
   R.; Zaric, D.; Zavrtanik, M.; Zavrtanik, D.; Zdziarski, A. A.; Zech,
   A.; Zechlin, H.; Zhdanov, V. I.; Živec, M.
Bibcode: 2021JCAP...01..057A
Altcode: 2020arXiv200716129C
  We provide an updated assessment of the power of the Cherenkov Telescope
  Array (CTA) to search for thermally produced dark matter at the TeV
  scale, via the associated gamma-ray signal from pair-annihilating dark
  matter particles in the region around the Galactic centre. We find
  that CTA will open a new window of discovery potential, significantly
  extending the range of robustly testable models given a standard cuspy
  profile of the dark matter density distribution. Importantly, even for
  a cored profile, the projected sensitivity of CTA will be sufficient to
  probe various well-motivated models of thermally produced dark matter
  at the TeV scale. This is due to CTA's unprecedented sensitivity,
  angular and energy resolutions, and the planned observational
  strategy. The survey of the inner Galaxy will cover a much larger
  region than corresponding previous observational campaigns with imaging
  atmospheric Cherenkov telescopes. CTA will map with unprecedented
  precision the large-scale diffuse emission in high-energy gamma rays,
  constituting a background for dark matter searches for which we adopt
  state-of-the-art models based on current data. Throughout our analysis,
  we use up-to-date event reconstruction Monte Carlo tools developed
  by the CTA consortium, and pay special attention to quantifying the
  level of instrumental systematic uncertainties, as well as background
  template systematic errors, required to probe thermally produced dark
  matter at these energies.

Title: A Journey of Exploration to the Polar Regions of a Star:
    Probing the Solar Poles and the Heliosphere from High Helio-Latitude
Authors: Finsterle, W.; Harra, L.; Andretta, V.; Appourchaux, T.;
   Baudin, F.; Bellot Rubio, L.; Birch, A.; Boumier, P.; Cameron, R. H.;
   Carlsson, M.; Corbard, T.; Davies, J. A.; Fazakerley, A. N.; Fineschi,
   S.; Gizon, L. C.; Harrison, R. A.; Hassler, D.; Leibacher, J. W.;
   Liewer, P. C.; Macdonald, M.; Maksimovic, M.; Murphy, N.; Naletto, G.;
   Nigro, G.; Owen, C. J.; Martinez-Pillet, V.; Rochus, P. L.; Romoli,
   M.; Sekii, T.; Spadaro, D.; Veronig, A.
Bibcode: 2020AGUFMSH0110005F
Altcode:
  A mission to view the solar poles from high helio-latitudes (above
  60°) will build on the experience of Solar Orbiter as well as a long
  heritage of successful solar missions and instrumentation (e.g. SOHO,
  STEREO, Hinode, SDO), but will focus for the first time on the solar
  poles, enabling scientific investigations that cannot be done by
  any other mission. One of the major mysteries of the Sun is the solar
  cycle. The activity cycle of the Sun drives the structure and behaviour
  of the heliosphere and is, of course, the driver of space weather. In
  addition, solar activity and variability provides fluctuating input
  into the Earth climate models, and these same physical processes
  are applicable to stellar systems hosting exoplanets. One of the
  main obstructions to understanding the solar cycle, and hence all
  solar activity, is our current lack of understanding of the polar
  regions. We describe a mission concept that aims to address this
  fundamental issue. In parallel, we recognise that viewing the Sun
  from above the polar regions enables further scientific advantages,
  beyond those related to the solar cycle, such as unique and powerful
  studies of coronal mass ejection processes, from a global perspective,
  and studies of coronal structure and activity in polar regions. Not
  only will these provide important scientific advances for fundamental
  stellar physics research, they will feed into our understanding of
  impacts on the Earth and other planets' space environment.

Title: Power spectrum of turbulent convection in the solar photosphere
Authors: Yelles Chaouche, L.; Cameron, R. H.; Solanki, S. K.;
   Riethmüller, T. L.; Anusha, L. S.; Witzke, V.; Shapiro, A. I.;
   Barthol, P.; Gandorfer, A.; Gizon, L.; Hirzberger, J.; van Noort,
   M.; Blanco Rodríguez, J.; Del Toro Iniesta, J. C.; Orozco Suárez,
   D.; Schmidt, W.; Martínez Pillet, V.; Knölker, M.
Bibcode: 2020A&A...644A..44Y
Altcode: 2020arXiv201009037Y
  The solar photosphere provides us with a laboratory for understanding
  turbulence in a layer where the fundamental processes of transport
  vary rapidly and a strongly superadiabatic region lies very closely
  to a subadiabatic layer. Our tools for probing the turbulence are
  high-resolution spectropolarimetric observations such as have recently
  been obtained with the two balloon-borne SUNRISE missions, and numerical
  simulations. Our aim is to study photospheric turbulence with the
  help of Fourier power spectra that we compute from observations
  and simulations. We also attempt to explain some properties of the
  photospheric overshooting flow with the help of its governing equations
  and simulations. We find that quiet-Sun observations and smeared
  simulations are consistent with each other and exhibit a power-law
  behavior in the subgranular range of their Doppler velocity power
  spectra with a power-law index of ≈ - 2. The unsmeared simulations
  exhibit a power law that extends over the full range between the
  integral and Taylor scales with a power-law index of ≈ - 2.25. The
  smearing, reminiscent of observational conditions, considerably reduces
  the extent of the power-law-like portion of the power spectra. This
  suggests that the limited spatial resolution in some observations
  might eventually result in larger uncertainties in the estimation of
  the power-law indices. The simulated vertical velocity power spectra
  as a function of height show a rapid change in the power-law index
  (at the subgranular range) from roughly the optical depth unity layer,
  that is, the solar surface, to 300 km above it. We propose that the
  cause of the steepening of the power-law index is the transition from
  a super- to a subadiabatic region, in which the dominant source of
  motions is overshooting convection. A scale-dependent transport of
  the vertical momentum occurs. At smaller scales, the vertical momentum
  is more efficiently transported sideways than at larger scales. This
  results in less vertical velocity power transported upward at small
  scales than at larger scales and produces a progressively steeper
  vertical velocity power law below 180 km. Above this height, the
  gravity work progressively gains importance at all relevant scales,
  making the atmosphere progressively more hydrostatic and resulting
  in a gradually less steep power law. Radiative heating and cooling of
  the plasma is shown to play a dominant role in the plasma energetics
  in this region, which is important in terms of nonadiabatic damping
  of the convective motions.

Title: Simulations Show that Vortex Flows Could Heat the Chromosphere
    in Solar Plage
Authors: Yadav, N.; Cameron, R.; Solanki, S.
Bibcode: 2020SPD....5120107Y
Altcode:
  Recent advances in both, observational techniques and numerical
  simulations have enabled us to detect small-scale vortices in the solar
  atmosphere. Vortices are ubiquitous throughout the solar surface and
  at all layers of the solar atmosphere existing over a wide range of
  spatial and temporal scales. Small-scale vortices are suggested to play
  an important role in the energy transport of the solar atmosphere,
  however, their physical properties remain poorly understood due
  to limited resolution. We explored the relationship between vortex
  flows at different spatial scales, analyze their physical properties,
  and investigate their contribution to Poynting flux transport. Using
  three-dimensional (3D) radiative magnetohydrodynamic (MHD)simulation
  code 'MURaM', we perform numerical simulations of a unipolar solar
  plage region. For detecting and isolating vortices, we use the
  'Swirling Strength' criterion. We explore the spatial profiles of
  physical quantities viz. density, horizontal velocity, etc. inside
  these vortices. Moreover, to apprehend their general characteristics,
  a statistical investigation is performed. We found that magnetic flux
  tubes have a complex filamentary substructure abundant of small-scale
  vortices. On their interfaces strong current sheets are formed that
  may dissipate and heat the solar chromosphere. Statistically, vortices
  have higher densities and higher temperatures than the average values
  at the same geometrical height. We also degrade our simulation data to
  get an effective spatial resolution of 50 km, 100 km, 250 km, and 500
  km, respectively. Analyzing simulation data at different effective
  resolutions, we found vortex flows existing over various spatial
  scales. In high-resolution simulation data, we detect a large number
  of small-scale vortices. Whereas, in the degraded data with relatively
  poor resolutions, smaller vortices are averaged-out and larger vortices
  are detected. The Poynting flux over vortex locations is more than
  adequate to compensate for the radiative losses in the chromosphere
  indicating their possible role in the chromospheric heating.

Title: A Coronal Loop in a Box: Energy Generation, Heating and
    Dynamics
Authors: Breu, C.; Peter, H.; Cameron, R.; Solanki, S.; Chitta, P.;
   Przybylski, D.
Bibcode: 2020SPD....5121008B
Altcode:
  In our study we aim at an understanding how the energy to heat the
  upper atmosphere is generated by the photospheric magneto-convection,
  transported into the upper atmosphere, and how its dissipation governs
  the formation of the internal structure of a coronal magnetic loop. In
  a 3D MHD model we study a coronal loop that is rooted with both
  footpoints in a shallow convection zone layer. Therefore the driving
  at the coronal base arises self-consistently from magneto-convection
  in plage-type areas. To fit into a cartesian box, we straighten the
  coronal loop. This allows a high spatial resolution within the loop
  that cannot be achieved in a model of a whole active region. To
  conduct the numerical experiments we employ the MURaM code that
  includes heat conduction, radiative transfer and optically thin
  radiative losses. We find that the Poynting flux into the loop is
  generated by small-scale photospheric motions within strong magnetic
  flux concentrations. Turbulent behaviour develops in the upper layers
  of the atmosphere as a response to the footpoint motions. Vortex flows
  are found at various heights within the loop. These are organised in
  swirls that form coherent structures with a magnetic connection from
  the intergranular lanes in the photosphere through the chromosphere
  up to several megameters into the corona. In the coronal part of
  the loop plasma motions perpendicular to the magnetic axis of the
  swirl are associated with an increased heating rate and thus enhanced
  temperatures. At any given time, only part of the loop is filled with
  swirls which leads to a substructure of the loop in terms of temperature
  and density. Consequently the emission as it would be observed by AIA
  or XRT reveals transient bright strands that form in response to the
  heating events related to the swirls. With this model we can build a
  coherent picture of how the energy flux to heat the upper atmosphere
  is generated near the solar surface and how this process drives and
  governs the heating and dynamics of a coronal loop

Title: Effects of inclusion of small-scale dynamo in near-surface
    structure of F-stars
Authors: Bhatia, T. S.; Cameron, R.; Solanki, S.; Peter, H.; Przbylski,
   D.; Witzke, V.
Bibcode: 2020SPD....5120704B
Altcode:
  The presence of (unresolved) small-scale mixed polarity regions in
  the quiet Sun photosphere plays an important role in determining
  the basal magnetic flux. Observationally, the magnitude of the
  vertical component of this field is estimated to be ~50-100 G on the
  Sun. This field is important for determining the energy balance in
  the chromosphere and may also subtly affect the radiative properties
  of the photosphere. These fields are believed to be the result of a
  small-scale dynamo (SSD) operating near the surface. While significant
  progress has been made in investigating the role of the SSD in the Sun,
  it is unclear what effects SSDs have on other stars. In particular,
  for F-stars, the photosheric kinetic and internal energies seem to be
  of the same order of magnitude. Since there is a rough equipartition
  in energies for a saturated SSD, deviations from a pure hydrodynamic
  (HD) stratification are expected. We aim to characterize these
  deviations. Box simulations of the upper convection zone and the
  photosphere are carried out using the radiative MHD code MURaM. To
  obtain SSD simulations, we use initial HD simulations and seed a
  magnetic field of negligible strength and zero net flux, which we
  then run till the magnetic field reaches saturation. We consider two
  different lower boundary conditions (BCs) for the magnetic field to
  characterize BC-effects: a) only vertical magnetic field is allowed, b)
  both vertical and horizontal magnetic field is allowed. Both boundary
  conditions exhibit SSD action. We observe slight increase (fraction
  of a percent) in the horizontally-averaged temperature profile for
  both the cases. Other thermodynamic quantities exhibit deviations (~
  a percent) depending on the boundary condition considered. In addition,
  the spatial power spectra of the bolometric intensity shows deviations
  from the corresponding HD (without magnetic field) run, implying
  larger power at smaller spatial scales for SSD case. The presence of
  a SSD results in a significant amount of "quiet"-star magnetic flux
  with associated changes in the stratification of the atmosphere and
  spatial distribution of the bolometric intensity.

Title: Average motion of emerging solar active region
    polarities. II. Joy's law
Authors: Schunker, H.; Baumgartner, C.; Birch, A. C.; Cameron, R. H.;
   Braun, D. C.; Gizon, L.
Bibcode: 2020A&A...640A.116S
Altcode: 2020arXiv200605565S
  Context. The tilt of solar active regions described by Joy's law
  is essential for converting a toroidal field to a poloidal field in
  Babcock-Leighton dynamo models. In thin flux tube models the Coriolis
  force causes what we observe as Joy's law, acting on east-west flows
  as they rise towards the surface. <BR /> Aims: Our goal is to measure
  the evolution of the average tilt angle of hundreds of active regions
  as they emerge, so that we can constrain the origins of Joy's law. <BR
  /> Methods: We measured the tilt angle of the primary bipoles in 153
  emerging active regions (EARs) in the Solar Dynamics Observatory
  Helioseismic Emerging Active Region survey. We used line-of-sight
  magnetic field measurements averaged over 6 h to define the polarities
  and measure the tilt angle up to four days after emergence. <BR />
  Results: We find that at the time of emergence the polarities are on
  average aligned east-west, and that neither the separation nor the
  tilt depends on latitude. We do find, however, that EARs at higher
  latitudes have a faster north-south separation speed than those closer
  to the equator at the emergence time. After emergence, the tilt
  angle increases and Joy's law is evident about two days later. The
  scatter in the tilt angle is independent of flux until about one day
  after emergence, when we find that higher-flux regions have a smaller
  scatter in tilt angle than lower-flux regions. <BR /> Conclusions:
  Our finding that active regions emerge with an east-west alignment
  is consistent with earlier observations, but is still surprising
  since thin flux tube models predict that tilt angles of rising flux
  tubes are generated below the surface. Previously reported tilt angle
  relaxation of deeply anchored flux tubes can be largely explained
  by the change in east-west separation. We conclude that Joy's law is
  caused by an inherent north-south separation speed present when the
  flux first reaches the surface, and that the scatter in the tilt angle
  is consistent with buffeting of the polarities by supergranulation.

Title: Radiative MHD Simulations of Starspots
Authors: Panja, M.; Cameron, R.; Solanki, S.
Bibcode: 2020SPD....5121117P
Altcode:
  We have performed the first-ever, realistic 3D simulations of the
  photospheric structure of complete starspots, including their penumbrae,
  for a range of cool main-sequence stars, namely the spectral types M0V,
  K0V, and G2V. We used the MHD code MURaM which includes radiative energy
  transfer and the effects of partial ionization. We explore several
  fundamental properties like umbral intensity contrast, temperature, and
  magnetic field strength as functions of spectral type. Our simulations
  show that there is an increase in spot contrast with the increase in
  stellar surface temperature, which is consistent with observations. The
  umbral field strength is determined by the depth at which the optical
  surface forms and the surface pressures of the host stars. We will
  present our results and discuss the physics behind them.

Title: Reply to the comment of T. Metcalfe and J. van Saders on the
    Science report "The Sun is less active than other solar-like stars"
Authors: Reinhold, T.; Shapiro, A. I.; Solanki, S. K.; Montet, B. T.;
   Krivova, N. A.; Cameron, R. H.; Amazo-Gómez, E. M.
Bibcode: 2020arXiv200704817R
Altcode:
  This is our reply to the comment of T. Metcalfe and J. van Saders
  on the Science report "The Sun is less active than other solar-like
  stars" by T. Reinhold, A. I. Shapiro, S. K. Solanki, B. T. Montet,
  N. A. Krivova, R. H. Cameron, E. M. Amazo-Gomez. We hope that both
  the comment and our reply lead to fruitful discussions which of the
  two presented scenarios is more likely.

Title: Meridional flow in the Sun’s convection zone is a single
    cell in each hemisphere
Authors: Gizon, Laurent; Cameron, Robert H.; Pourabdian, Majid; Liang,
   Zhi-Chao; Fournier, Damien; Birch, Aaron C.; Hanson, Chris S.
Bibcode: 2020Sci...368.1469G
Altcode:
  The Sun’s magnetic field is generated by subsurface motions of the
  convecting plasma. The latitude at which the magnetic field emerges
  through the solar surface (as sunspots) drifts toward the equator
  over the course of the 11-year solar cycle. We use helioseismology to
  infer the meridional flow (in the latitudinal and radial directions)
  over two solar cycles covering 1996-2019. Two data sources are used,
  which agree during their overlap period of 2001-2011. The time-averaged
  meridional flow is shown to be a single cell in each hemisphere,
  carrying plasma toward the equator at the base of the convection zone
  with a speed of ~4 meters per second at 45° latitude. Our results
  support the flux-transport dynamo model, which explains the drift of
  sunspot-emergence latitudes through the meridional flow.

Title: Simulations Show that Vortex Flows Could Heat the Chromosphere
    in Solar Plage
Authors: Yadav, Nitin; Cameron, R. H.; Solanki, S. K.
Bibcode: 2020ApJ...894L..17Y
Altcode: 2020arXiv200413996Y
  The relationship between vortex flows at different spatial scales
  and their contribution to the energy balance in the chromosphere
  is not yet fully understood. We perform three-dimensional (3D)
  radiation-magnetohydrodynamic simulations of a unipolar solar plage
  region at a spatial resolution of 10 km using the MURaM code. We
  use the swirling-strength criterion that mainly detects the smallest
  vortices present in the simulation data. We additionally degrade our
  simulation data to smooth out the smaller vortices, so that also the
  vortices at larger spatial scales can be detected. Vortex flows at
  various spatial scales are found in our simulation data for different
  effective spatial resolutions. We conclude that the observed large
  vortices are likely clusters of much smaller ones that are not yet
  resolved by observations. We show that the vertical Poynting flux
  decreases rapidly with reduced effective spatial resolutions and
  is predominantly carried by the horizontal plasma motions rather
  than vertical flows. Since the small-scale horizontal motions or the
  smaller vortices carry most of the energy, the energy transported by
  vortices deduced from low-resolution data is grossly underestimated. In
  full-resolution simulation data, the Poynting flux contribution due to
  vortices is more than adequate to compensate for the radiative losses
  in plage, indicating their importance for chromospheric heating.

Title: Rossby modes in slowly rotating stars: depth dependence in
    distorted polytropes with uniform rotation
Authors: Damiani, C.; Cameron, R. H.; Birch, A. C.; Gizon, L.
Bibcode: 2020A&A...637A..65D
Altcode: 2020arXiv200305276D
  Context. Large-scale Rossby waves have recently been discovered based on
  measurements of horizontal surface and near-surface solar flows. <BR />
  Aims: We are interested in understanding why it is only equatorial modes
  that are observed and in modelling the radial structure of the observed
  modes. To this aim, we have characterised the radial eigenfunctions
  of r modes for slowly rotating polytropes in uniform rotation. <BR
  /> Methods: We followed Provost et al. (1981, A&amp;A, 94, 126) and
  considered a linear perturbation theory to describe quasi-toroidal
  stellar adiabatic oscillations in the inviscid case. We used
  perturbation theory to write the solutions to the fourth order in the
  rotational frequency of the star. We numerically solved the eigenvalue
  problem, concentrating on the type of behaviour exhibited where the
  stratification is nearly adiabatic. <BR /> Results: We find that for
  free-surface boundary conditions on a spheroid of non-vanishing surface
  density, r modes can only exist for ℓ = m spherical harmonics in the
  inviscid case and we compute their depth dependence and frequencies to
  leading order. For quasi-adiabatic stratification, the sectoral modes
  with no radial nodes are the only modes which are almost toroidal and
  the depth dependence of the corresponding horizontal motion scales as
  r<SUP>m</SUP>. For all r modes, except the zero radial order sectoral
  ones, non-adiabatic stratification plays a crucial role in the radial
  force balance. <BR /> Conclusions: The lack of quasi-toroidal solutions
  when stratification is close to neutral, except for the sectoral modes
  without nodes in radius, follows from the need for both horizontal
  and radial force balance. In the absence of super- or sub-adiabatic
  stratification and viscosity, both the horizontal and radial parts of
  the force balance independently determine the pressure perturbation. The
  only quasi-toroidal cases in which these constraints on the pressure
  perturbation are consistent are the special cases where ℓ = m and
  the horizontal displacement scales with r<SUP>m</SUP>.

Title: Towards a more reliable reconstruction of the historical
solar variability: a more realistic description of solar ephemeral
    magnetic regions
Authors: Hofer, Bernhard; Krivova, Natalie A.; Wu, Chi-Ju; Usoskin,
   Ilya A.; Cameron, Robert
Bibcode: 2020EGUGA..2217086H
Altcode:
  Solar irradiance is a crucial input to climate models, but its
  measurements are only available since 1978. The variability of
  solar irradiance on climate-relevant time-scales is caused by
  the competition between bright and dark features formed by the
  magnetic fields emerging on the solar surface. Thus, models have
  been developed that reconstruct past irradiance variability from
  proxies of the solar magnetic activity. The longest direct proxy is
  the sunspot number. The common problem of such reconstructions is,
  however, that while sunspots adequately describe the evolution of
  the active regions (ARs) (large bipolar regions hosting sunspots),
  the evolution of their smaller counterparts, the ephemeral regions
  (ERs), is not directly featured by sunspots. At the same time, these
  small regions are much more numerous and are believed to be the main
  source of the long-term irradiance changes, which are of special
  interest to climate models. We develop an improved description of
  the ephemeral region emergence taking different solar observational
  constraints into account. The model builds on the SATIRE-T model, in
  which the emergence of ARs is described by the sunspot number and the
  emergence of the ERs is linearly linked to that of ARs. The latter,
  however, implies that whenever the sunspot number drops to zero, no
  magnetic field emerges in the model. In the new model, the emergence
  of the ERs is no longer linked to sunspots linearly. Instead, ARs and
  ERs are considered to be parts of a single power-law size distribution
  of the emerging magnetic regions. This ensures that even in the absence
  of ARs (e.g., during the grand minima of solar activity), the emergence
  rate of ERs remains non-zero. In particular, the solar open magnetic
  flux reconstructed using this approach does not drop to zero during
  the Maunder minimum, in agreement with independent reconstructions
  from the cosmogenic isotope data. Such an improved description of the
  ERs will allow a better constraint on the maximum solar irradiance
  drop during grand minima events. This, in turn, will allow a better
  constraint on the potential solar forcing in the future.

Title: The Sun is less active than other solar-like stars
Authors: Reinhold, Timo; Shapiro, Alexander I.; Solanki, Sami K.;
   Montet, Benjamin T.; Krivova, Natalie A.; Cameron, Robert H.;
   Amazo-Gómez, Eliana M.
Bibcode: 2020Sci...368..518R
Altcode: 2020arXiv200501401R
  The magnetic activity of the Sun and other stars causes their brightness
  to vary. We investigated how typical the Sun’s variability is
  compared with other solar-like stars, i.e., those with near-solar
  effective temperatures and rotation periods. By combining 4 years
  of photometric observations from the Kepler space telescope with
  astrometric data from the Gaia spacecraft, we were able to measure
  photometric variabilities of 369 solar-like stars. Most of those with
  well-determined rotation periods showed higher variability than the Sun
  and are therefore considerably more active. These stars appear nearly
  identical to the Sun except for their higher variability. Therefore,
  we speculate that the Sun could potentially also go through epochs of
  such high variability.

Title: Power spectra of solar brightness variations at various
    inclinations
Authors: Nèmec, N. -E.; Shapiro, A. I.; Krivova, N. A.; Solanki,
   S. K.; Tagirov, R. V.; Cameron, R. H.; Dreizler, S.
Bibcode: 2020A&A...636A..43N
Altcode: 2020arXiv200210895N
  Context. Magnetic features on the surfaces of cool stars lead to
  variations in their brightness. Such variations on the surface of
  the Sun have been studied extensively. Recent planet-hunting space
  telescopes have made it possible to measure brightness variations
  in hundred thousands of other stars. The new data may undermine
  the validity of setting the sun as a typical example of a variable
  star. Putting solar variability into the stellar context suffers,
  however, from a bias resulting from solar observations being carried
  out from its near-equatorial plane, whereas stars are generally
  observed at all possible inclinations. <BR /> Aims: We model solar
  brightness variations at timescales from days to years as they would
  be observed at different inclinations. In particular, we consider the
  effect of the inclination on the power spectrum of solar brightness
  variations. The variations are calculated in several passbands that are
  routinely used for stellar measurements. <BR /> Methods: We employ the
  surface flux transport model to simulate the time-dependent spatial
  distribution of magnetic features on both the near and far sides of
  the Sun. This distribution is then used to calculate solar brightness
  variations following the Spectral And Total Irradiance REconstruction
  approach. <BR /> Results: We have quantified the effect of the
  inclination on solar brightness variability at timescales down to a
  single day. Thus, our results allow for solar brightness records to
  be made directly comparable to those obtained by planet-hunting space
  telescopes. Furthermore, we decompose solar brightness variations into
  components originating from the solar rotation and from the evolution
  of magnetic features.

Title: 3D Radiative MHD Simulations of Starspots
Authors: Panja, Mayukh; Cameron, Robert; Solanki, Sami K.
Bibcode: 2020ApJ...893..113P
Altcode: 2020arXiv200309656P
  There are no direct spatially resolved observations of spots on stars
  other than the Sun, and starspot properties are inferred indirectly
  through lightcurves and spectropolarimetric data. We present the first
  self-consistent 3D radiative MHD computations of starspots on G2V, K0V,
  and M0V stars, which will help us to better understand observations of
  activity, variability, and magnetic fields in late-type main-sequence
  stars. We used the MURaM code, which has been extensively used to
  compute "realistic" sunspots, for our simulations. We aim to study
  how fundamental starspot properties such as intensity contrast,
  temperature, and magnetic field strength vary with spectral type. We
  first simulated in 2D multiple spots of each spectral type to find
  out appropriate initial conditions for our 3D runs. We find that
  with increasing stellar effective temperature, there is an increase
  in the temperature difference between the umbra of the spot and its
  surrounding photosphere, from 350 K on the M0V star to 1400 K on the
  G2V star. This trend in our simulated starspots is consistent with
  observations. The magnetic field strengths of all the starspot umbrae
  are in the 3-4.5 kG range. The G2V and K0V umbrae have comparable
  magnetic field strengths around 3.5 kG, while the M0V umbra has a
  relatively higher field strength around 4 kG. We discuss the physical
  reasons behind both these trends. All of the three starspots develop
  penumbral filament-like structures with Evershed flows. The average
  Evershed flow speed drops from 1.32 km s<SUP>-1</SUP> in the G2V
  penumbra to 0.6 km s<SUP>-1</SUP> in the M0V penumbra.

Title: Loss of toroidal magnetic flux by emergence of bipolar
    magnetic regions
Authors: Cameron, R. H.; Schüssler, M.
Bibcode: 2020A&A...636A...7C
Altcode: 2020arXiv200205436C
  The polarity of the toroidal magnetic field in the solar convection
  zone periodically reverses in the course of the 11/22-year solar
  cycle. Among the various processes that contribute to the removal of
  "old-polarity" toroidal magnetic flux is the emergence of flux loops
  forming bipolar regions at the solar surface. We quantify the loss of
  subsurface net toroidal flux by this process. To this end, we determine
  the contribution of an individual emerging bipolar loop and show that
  it is unaffected by surface flux transport after emergence. Together
  with the linearity of the diffusion process this means that the
  total flux loss can be obtained by adding the contributions of all
  emerging bipolar magnetic regions. The resulting total loss rate of
  net toroidal flux amounts to 1.3 × 10<SUP>15</SUP> Mx s<SUP>-1</SUP>
  during activity maxima and 6.1 × 10<SUP>14</SUP> Mx s<SUP>-1</SUP>
  during activity minima, to which ephemeral regions contribute about 90
  and 97%, respectively. This rate is consistent with the observationally
  inferred loss rate of toroidal flux into interplanetary space and
  corresponds to a decay time of the subsurface toroidal flux of about
  12 years, also consistent with a simple estimate based on turbulent
  diffusivity. Consequently, toroidal flux loss by flux emergence is a
  relevant contribution to the budget of net toroidal flux in the solar
  convection zone. The consistency between the toroidal flux loss rate
  due to flux emergence and what is expected from turbulent diffusion,
  and the similarity between the corresponding decay time and the length
  of the solar cycle are important constraints for understanding the
  solar cycle and the Sun's internal dynamics.

Title: The relationship between flux emergence and subsurface toroidal
    magnetic flux
Authors: Cameron, R. H.; Jiang, J.
Bibcode: 2019A&A...631A..27C
Altcode: 2019arXiv190906828C
  <BR /> Aims: The 1D mean-field equation describing the evolution of
  the subsurface toroidal field can be used with the observed surface
  radial field to model the subsurface toroidal flux density. Our aim
  is to test this model and determine the relationship between the
  observationally inferred surface toroidal field (as a proxy for flux
  emergence), and the modelled subsurface toroidal flux density. <BR />
  Methods: We used a combination of sunspot area observations and the
  surface toroidal field inferred from Wilcox Solar Observatory (WSO)
  line-of-sight magnetic field observations. We then compared them with
  the results of a 1D mean-field evolution equation for the subsurface
  toroidal field, driven by the observed radial field from the National
  Solar Observatory/Kitt Peak and SOLIS observations. <BR /> Results:
  We derive calibration curves relating the subsurface toroidal flux
  density to the observed surface toroidal field strengths and sunspot
  areas. The calibration curves are for two regimes, one corresponding to
  ephemeral region emergence outside of the butterfly wings, the other
  to active region emergence in the butterfly wings. We discuss this in
  terms of the size and vertical velocity associated with the two types
  of flux emergence.

Title: Monte Carlo studies for the optimisation of the Cherenkov
    Telescope Array layout
Authors: Acharyya, A.; Agudo, I.; Angüner, E. O.; Alfaro, R.;
   Alfaro, J.; Alispach, C.; Aloisio, R.; Alves Batista, R.; Amans,
   J. -P.; Amati, L.; Amato, E.; Ambrosi, G.; Antonelli, L. A.; Aramo,
   C.; Armstrong, T.; Arqueros, F.; Arrabito, L.; Asano, K.; Ashkar,
   H.; Balazs, C.; Balbo, M.; Balmaverde, B.; Barai, P.; Barbano, A.;
   Barkov, M.; Barres de Almeida, U.; Barrio, J. A.; Bastieri, D.;
   Becerra González, J.; Becker Tjus, J.; Bellizzi, L.; Benbow, W.;
   Bernardini, E.; Bernardos, M. I.; Bernlöhr, K.; Berti, A.; Berton,
   M.; Bertucci, B.; Beshley, V.; Biasuzzi, B.; Bigongiari, C.; Bird,
   R.; Bissaldi, E.; Biteau, J.; Blanch, O.; Blazek, J.; Boisson, C.;
   Bonanno, G.; Bonardi, A.; Bonavolontá, C.; Bonnoli, G.; Bordas,
   P.; Böttcher, M.; Bregeon, J.; Brill, A.; Brown, A. M.; Brügge,
   K.; Brun, P.; Bruno, P.; Bulgarelli, A.; Bulik, T.; Burton, M.;
   Burtovoi, A.; Busetto, G.; Cameron, R.; Canestrari, R.; Capalbi, M.;
   Caproni, A.; Capuzzo-Dolcetta, R.; Caraveo, P.; Caroff, S.; Carosi,
   R.; Casanova, S.; Cascone, E.; Cassol, F.; Catalani, F.; Catalano,
   O.; Cauz, D.; Cerruti, M.; Chaty, S.; Chen, A.; Chernyakova, M.;
   Chiaro, G.; Cieślar, M.; Colak, S. M.; Conforti, V.; Congiu, E.;
   Contreras, J. L.; Cortina, J.; Costa, A.; Costantini, H.; Cotter, G.;
   Cristofari, P.; Cumani, P.; Cusumano, G.; D'Aí, A.; D'Ammando, F.;
   Dangeon, L.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Caprio, V.;
   de Cássia dos Anjos, R.; De Frondat, F.; de Gouveia Dal Pino, E. M.;
   De Lotto, B.; De Martino, D.; de Naurois, M.; de Oña Wilhelmi, E.;
   de Palma, F.; de Souza, V.; Del Santo, M.; Delgado, C.; della Volpe,
   D.; Di Girolamo, T.; Di Pierro, F.; Di Venere, L.; Díaz, C.; Diebold,
   S.; Djannati-Ataï, A.; Dmytriiev, A.; Dominis Prester, D.; Donini,
   A.; Dorner, D.; Doro, M.; Dournaux, J. -L.; Ebr, J.; Ekoume, T. R. N.;
   Elsässer, D.; Emery, G.; Falceta-Goncalves, D.; Fedorova, E.; Fegan,
   S.; Feng, Q.; Ferrand, G.; Fiandrini, E.; Fiasson, A.; Filipovic,
   M.; Fioretti, V.; Fiori, M.; Flis, S.; Fonseca, M. V.; Fontaine, G.;
   Freixas Coromina, L.; Fukami, S.; Fukui, Y.; Funk, S.; Füßling,
   M.; Gaggero, D.; Galanti, G.; Garcia López, R. J.; Garczarczyk, M.;
   Gascon, D.; Gasparetto, T.; Gaug, M.; Ghalumyan, A.; Gianotti, F.;
   Giavitto, G.; Giglietto, N.; Giordano, F.; Giroletti, M.; Gironnet,
   J.; Glicenstein, J. -F.; Gnatyk, R.; Goldoni, P.; González, J. M.;
   González, M. M.; Gourgouliatos, K. N.; Grabarczyk, T.; Granot,
   J.; Green, D.; Greenshaw, T.; Grondin, M. -H.; Gueta, O.; Hadasch,
   D.; Hassan, T.; Hayashida, M.; Heller, M.; Hervet, O.; Hinton, J.;
   Hiroshima, N.; Hnatyk, B.; Hofmann, W.; Horvath, P.; Hrabovsky, M.;
   Hrupec, D.; Humensky, T. B.; Hütten, M.; Inada, T.; Iocco, F.; Ionica,
   M.; Iori, M.; Iwamura, Y.; Jamrozy, M.; Janecek, P.; Jankowsky, D.;
   Jean, P.; Jouvin, L.; Jurysek, J.; Kaaret, P.; Kadowaki, L. H. S.;
   Karkar, S.; Kerszberg, D.; Khélifi, B.; Kieda, D.; Kimeswenger,
   S.; Kluźniak, W.; Knapp, J.; Knödlseder, J.; Kobayashi, Y.; Koch,
   B.; Kocot, J.; Komin, N.; Kong, A.; Kowal, G.; Krause, M.; Kubo,
   H.; Kushida, J.; Kushwaha, P.; La Parola, V.; La Rosa, G.; Lallena
   Arquillo, M.; Lang, R. G.; Lapington, J.; Le Blanc, O.; Lefaucheur, J.;
   Leigui de Oliveira, M. A.; Lemoine-Goumard, M.; Lenain, J. -P.; Leto,
   G.; Lico, R.; Lindfors, E.; Lohse, T.; Lombardi, S.; Longo, F.; Lopez,
   A.; López, M.; Lopez-Oramas, A.; López-Coto, R.; Loporchio, S.;
   Luque-Escamilla, P. L.; Lyard, E.; Maccarone, M. C.; Mach, E.; Maggio,
   C.; Majumdar, P.; Malaguti, G.; Mallamaci, M.; Mandat, D.; Maneva, G.;
   Manganaro, M.; Mangano, S.; Marculewicz, M.; Mariotti, M.; Martí, J.;
   Martínez, M.; Martínez, G.; Martínez-Huerta, H.; Masuda, S.; Maxted,
   N.; Mazin, D.; Meunier, J. -L.; Meyer, M.; Micanovic, S.; Millul, R.;
   Minaya, I. A.; Mitchell, A.; Mizuno, T.; Moderski, R.; Mohrmann, L.;
   Montaruli, T.; Moralejo, A.; Morcuende, D.; Morlino, G.; Morselli, A.;
   Moulin, E.; Mukherjee, R.; Munar, P.; Mundell, C.; Murach, T.; Nagai,
   A.; Nagayoshi, T.; Naito, T.; Nakamori, T.; Nemmen, R.; Niemiec, J.;
   Nieto, D.; Nievas Rosillo, M.; Nikołajuk, M.; Ninci, D.; Nishijima,
   K.; Noda, K.; Nosek, D.; Nöthe, M.; Nozaki, S.; Ohishi, M.; Ohtani,
   Y.; Okumura, A.; Ong, R. A.; Orienti, M.; Orito, R.; Ostrowski, M.;
   Otte, N.; Ou, Z.; Oya, I.; Pagliaro, A.; Palatiello, M.; Palatka, M.;
   Paoletti, R.; Paredes, J. M.; Pareschi, G.; Parmiggiani, N.; Parsons,
   R. D.; Patricelli, B.; Pe'er, A.; Pech, M.; Peñil Del Campo, P.;
   Pérez-Romero, J.; Perri, M.; Persic, M.; Petrucci, P. -O.; Petruk,
   O.; Pfrang, K.; Piel, Q.; Pietropaolo, E.; Pohl, M.; Polo, M.;
   Poutanen, J.; Prandini, E.; Produit, N.; Prokoph, H.; Prouza, M.;
   Przybilski, H.; Pühlhofer, G.; Punch, M.; Queiroz, F.; Quirrenbach,
   A.; Rainò, S.; Rando, R.; Razzaque, S.; Reimer, O.; Renault-Tinacci,
   N.; Renier, Y.; Ribeiro, D.; Ribó, M.; Rico, J.; Rieger, F.; Rizi,
   V.; Rodriguez Fernandez, G.; Rodriguez-Ramirez, J. C.; Rodrí-guez
   Vázquez, J. J.; Romano, P.; Romeo, G.; Roncadelli, M.; Rosado,
   J.; Rowell, G.; Rudak, B.; Rugliancich, A.; Rulten, C.; Sadeh, I.;
   Saha, L.; Saito, T.; Sakurai, S.; Salesa Greus, F.; Sangiorgi, P.;
   Sano, H.; Santander, M.; Santangelo, A.; Santos-Lima, R.; Sanuy,
   A.; Satalecka, K.; Saturni, F. G.; Sawangwit, U.; Schlenstedt, S.;
   Schovanek, P.; Schussler, F.; Schwanke, U.; Sciacca, E.; Scuderi,
   S.; Sedlaczek, K.; Seglar-Arroyo, M.; Sergijenko, O.; Seweryn, K.;
   Shalchi, A.; Shellard, R. C.; Siejkowski, H.; Sillanpää, A.; Sinha,
   A.; Sironi, G.; Sliusar, V.; Slowikowska, A.; Sol, H.; Specovius, A.;
   Spencer, S.; Spengler, G.; Stamerra, A.; Stanič, S.; Stawarz, Ł.;
   Stefanik, S.; Stolarczyk, T.; Straumann, U.; Suomijarvi, T.; Świerk,
   P.; Szepieniec, T.; Tagliaferri, G.; Tajima, H.; Tam, T.; Tavecchio,
   F.; Taylor, L.; Tejedor, L. A.; Temnikov, P.; Terzic, T.; Testa, V.;
   Tibaldo, L.; Todero Peixoto, C. J.; Tokanai, F.; Tomankova, L.; Tonev,
   D.; Torres, D. F.; Tosti, G.; Tosti, L.; Tothill, N.; Toussenel, F.;
   Tovmassian, G.; Travnicek, P.; Trichard, C.; Umana, G.; Vagelli, V.;
   Valentino, M.; Vallage, B.; Vallania, P.; Valore, L.; Vandenbroucke,
   J.; Varner, G. S.; Vasileiadis, G.; Vassiliev, V.; Vázquez Acosta,
   M.; Vecchi, M.; Vercellone, S.; Vergani, S.; Vettolani, G. P.; Viana,
   A.; Vigorito, C. F.; Vink, J.; Vitale, V.; Voelk, H.; Vollhardt,
   A.; Vorobiov, S.; Wagner, S. J.; Walter, R.; Werner, F.; White,
   R.; Wierzcholska, A.; Will, M.; Williams, D. A.; Wischnewski, R.;
   Yang, L.; Yoshida, T.; Yoshikoshi, T.; Zacharias, M.; Zampieri, L.;
   Zavrtanik, M.; Zavrtanik, D.; Zdziarski, A. A.; Zech, A.; Zechlin,
   H.; Zenin, A.; Zhdanov, V. I.; Zimmer, S.; Zorn, J.
Bibcode: 2019APh...111...35A
Altcode: 2019arXiv190401426A
  The Cherenkov Telescope Array (CTA) is the major next-generation
  observatory for ground-based very-high-energy gamma-ray astronomy. It
  will improve the sensitivity of current ground-based instruments by a
  factor of five to twenty, depending on the energy, greatly improving
  both their angular and energy resolutions over four decades in energy
  (from 20 GeV to 300 TeV). This achievement will be possible by using
  tens of imaging Cherenkov telescopes of three successive sizes. They
  will be arranged into two arrays, one per hemisphere, located on
  the La Palma island (Spain) and in Paranal (Chile). We present here
  the optimised and final telescope arrays for both CTA sites, as well
  as their foreseen performance, resulting from the analysis of three
  different large-scale Monte Carlo productions.

Title: Solar activity: periodicities beyond 11 years are consistent
    with random forcing
Authors: Cameron, R. H.; Schüssler, M.
Bibcode: 2019A&A...625A..28C
Altcode:
  Power spectra of solar activity based on historical records of sunspot
  numbers and on cosmogenic isotopes show peaks with enhanced power
  apart from the dominant 11-year solar cycle, such as the 90-year
  Gleissberg cycle or the 210-year de Vries cycle. In a previous paper
  we have shown that the overall shape of the power spectrum is well
  represented by the results of the generic normal form model for a
  noisy and weakly nonlinear limit cycle, with parameters all determined
  by observations. Using this model as a null case, we show here that
  all local peaks with enhanced power, apart from the 11-year band,
  are consistent with realization noise. Even a 3σ peak is expected
  to occur with a probability of about 0.25 at least once among the 216
  period bins resolved by the cosmogenic isotope data. This casts doubt
  upon interpretations of such peaks in terms of intrinsic periodicities
  of the solar dynamo process.

Title: Average motion of emerging solar active region
    polarities. I. Two phases of emergence
Authors: Schunker, H.; Birch, A. C.; Cameron, R. H.; Braun, D. C.;
   Gizon, L.; Burston, R. B.
Bibcode: 2019A&A...625A..53S
Altcode: 2019arXiv190311839S
  <BR /> Aims: Our goal is to constrain models of active region
  formation by tracking the average motion of active region polarity
  pairs as they emerge onto the surface. <BR /> Methods: We measured
  the motion of the two main opposite polarities in 153 emerging active
  regions using line-of-sight magnetic field observations from the Solar
  Dynamics Observatory Helioseismic Emerging Active Region (SDO/HEAR)
  survey. We first measured the position of each of the polarities
  eight hours after emergence, when they could be clearly identified,
  using a feature recognition method. We then tracked their location
  forwards and backwards in time. <BR /> Results: We find that, on
  average, the polarities emerge with an east-west orientation and the
  separation speed between the polarities increases. At about 0.1 days
  after emergence, the average separation speed reaches a peak value
  of 229 ± 11 ms<SUP>-1</SUP>, and then starts to decrease. About
  2.5 days after emergence the polarities stop separating. We also
  find that the separation and the separation speed in the east-west
  direction are systematically larger for active regions that have
  higher flux. The scatter in the location of the polarities increases
  from about 5 Mm at the time of emergence to about 15 Mm at two days
  after emergence. <BR /> Conclusions: Our results reveal two phases of
  the emergence process defined by the rate of change of the separation
  speed as the polarities move apart. Phase 1 begins when the opposite
  polarity pairs first appear at the surface, with an east-west alignment
  and an increasing separation speed. We define Phase 2 to begin when
  the separation speed starts to decrease, and ends when the polarities
  have stopped separating. This is consistent with a previous study: the
  peak of a flux tube breaks through the surface during Phase 1. During
  Phase 2 the magnetic field lines are straightened by magnetic tension,
  so that the polarities continue to move apart, until they eventually
  lie directly above their anchored subsurface footpoints. The scatter
  in the location of the polarities is consistent with the length and
  timescales of supergranulation, supporting the idea that convection
  buffets the polarities as they separate.

Title: Solar activity: intrinsic periodicities beyond 11 years
Authors: Cameron, Robert; Schuessler, Manfred
Bibcode: 2019arXiv190305398C
Altcode:
  Power spectra of solar activity based on historical records of sunspot
  numbers and on cosmogenic isotopes show peaks with enhanced power
  apart from the dominant 11-year solar cycle, such as the 90-year
  Gleissberg cycle or the 210-year de Vries cycle. In a previous paper
  we have shown that the overall shape of the power spectrum is well
  represented by the results of the generic normal form model for a
  noisy and weakly nonlinear limit cycle, with parameters all determined
  by observations. Using this model as a null case, we show here that
  all local peaks with enhanced power, apart from the 11-year band, are
  consistent with realisation noise. Even a $3\sigma$ peak is expected
  to occur with a probability of about 0.25 at least once among the 216
  period bins resolved by the cosmogenic isotope data. This casts doubt
  upon interpretations of such peaks in terms of intrinsic periodicities
  of the solar dynamo process.

Title: Starspot rotation rates versus activity cycle phase: Butterfly
    diagrams of Kepler stars are unlike that of the Sun
Authors: Nielsen, M. B.; Gizon, L.; Cameron, R. H.; Miesch, M.
Bibcode: 2019A&A...622A..85N
Altcode: 2018arXiv181206414N
  Context. During the solar magnetic activity cycle the emergence
  latitudes of sunspots change, leading to the well-known butterfly
  diagram. This phenomenon is poorly understood for other stars since
  starspot latitudes are generally unknown. The related changes in
  starspot rotation rates caused by latitudinal differential rotation can,
  however, be measured. <BR /> Aims: Using the set of 3093 Kepler stars
  with measured activity cycles, we aim to study the temporal change in
  starspot rotation rates over magnetic activity cycles, and how this
  relates to the activity level, the mean rotation rate of the star, and
  its effective temperature. <BR /> Methods: We measured the photometric
  variability as a proxy for the magnetic activity and the spot rotation
  rate in each quarter over the duration of the Kepler mission. We
  phase-folded these measurements with the cycle period. To reduce random
  errors, we performed averages over stars with comparable mean rotation
  rates and effective temperature at fixed activity-cycle phases. <BR />
  Results: We detect a clear correlation between the variation of activity
  level and the variation of the starspot rotation rate. The sign and
  amplitude of this correlation depends on the mean stellar rotation and -
  to a lesser extent - on the effective temperature. For slowly rotating
  stars (rotation periods between 15 - 28 days), the starspot rotation
  rates are clearly anti-correlated with the level of activity during
  the activity cycles. A transition is observed around rotation periods
  of 10 - 15 days, where stars with an effective temperature above 4200 K
  instead show positive correlation. <BR /> Conclusions: Our measurements
  can be interpreted in terms of a stellar "butterfly diagram",
  but these appear different from that of the Sun since the starspot
  rotation rates are either in phase or anti-phase with the activity
  level. Alternatively, the activity cycle periods observed by Kepler are
  short (around 2.5 years) and may therefore be secondary cycles, perhaps
  analogous to the solar quasi-biennial oscillations. <P />Rotation and
  activity tables are only available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr/">http://cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/622/A85">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/622/A85</A>

Title: The solar dynamo: Inferences from observations
Authors: Cameron, Robert
Bibcode: 2018csc..confE...4C
Altcode:
  We will show that the observed large-scale structure of the poloidal and
  toroidal magnetic fields, together with the differential rotation and
  surface meridional flow argue strongly in favour of a Babcock-Leighton
  dynamo. The cycle-to-cycle variability is consistent with the idea
  that flux emergence takes place in a turbulent environment, and we will
  discuss some of the implications of this in the context of the model.

Title: Statistical constraints on active region emergence from the
    surface motion of the polarities
Authors: Schunker, Hannah; Birch, Aaron; Cameron, Robert; Braun,
   Doug; Gizon, Laurent
Bibcode: 2018csc..confE..45S
Altcode:
  We measured the motion of the two main opposite polarities in
  154 emerging active regions using line-of-sight magnetograms from
  SDO/HMI. Our results reveal two phases of the emergence process defined
  by the rate of change of the separation speed as the polarities move
  apart. Phase one begins when the opposite polarity pairs first appear at
  the surface, with an east-west alignment and an increasing separation
  speed of 1.6 +/- 0.4 km/s. Phase two begins when the separation speed
  starts to decrease, about 0.1 days after emergence, and ends about 2.5
  days after emergence when the polarities have stopped separating. This
  is consistent with the picture of Chen, Rempel, &amp; Fan (2017):
  during phase one, the peak of a flux tube breaks through the surface
  and then, during phase two, the magnetic field lines are straightened
  by magnetic tension to eventually lie directly above their subsurface
  footpoints. The scatter in the location of the polarities is consistent
  with the length and time scales of supergranulation, supporting the idea
  that convection buffets the polarities as they separate. On average,
  the polarities emerge with an east-west orientation with the tilt angle
  developing over time independent of flux, in contrast to predictions
  from thin flux tube theory.

Title: VizieR Online Data Catalog: Starspot rotation rates
    vs. activity cycle phase (Nielsen+, 2019)
Authors: Nielsen, M. B.; Gizon, L.; Cameron, R. H.; Miesch, M.
Bibcode: 2018yCat..36220085N
Altcode:
  Activity cycle parameters for 3093 stars observed by Kepler, with
  measured cycle periods from Reinhold et al. (2017A&amp;A...603A..52R,
  Cat. J/A+A/603/A52). The integral, A, of the power density
  spectrum around the mean rotation rate (nurot, from McQuillan et
  al. (2014ApJS..211...24M, Cat. J/ApJS/211/24)) is used as proxy for
  magnetic activity. This and the rotation rate, nu, are traced from
  quarters Q1 to Q17 of Kepler observations. <P />(1 data file).

Title: Origin of the hemispheric asymmetry of solar activity
Authors: Schüssler, M.; Cameron, R. H.
Bibcode: 2018A&A...618A..89S
Altcode: 2018arXiv180710061S
  The frequency spectrum of the hemispheric asymmetry of solar activity
  shows enhanced power for the period ranges around 8.5 years and
  between 30 and 50 years. This can be understood as the sum and beat
  periods of the superposition of two dynamo modes: a dipolar mode with
  a (magnetic) period of about 22 years and a quadrupolar mode with a
  period between 13 and 15 years. An updated Babcock-Leighton-type dynamo
  model with weak driving as indicated by stellar observations shows
  an excited dipole mode and a damped quadrupole mode in the correct
  range of periods. Random excitation of the quadrupole by stochastic
  fluctuations of the source term for the poloidal field leads to a
  time evolution of activity and asymmetry that is consistent with the
  observational results.

Title: Chromospheric activity catalogue of 4454 cool
    stars. Questioning the active branch of stellar activity cycles
Authors: Boro Saikia, S.; Marvin, C. J.; Jeffers, S. V.; Reiners,
   A.; Cameron, R.; Marsden, S. C.; Petit, P.; Warnecke, J.; Yadav, A. P.
Bibcode: 2018A&A...616A.108B
Altcode: 2018A&A...616A.108S; 2018arXiv180311123B
  Context. Chromospheric activity monitoring of a wide range of cool
  stars can provide valuable information on stellar magnetic activity
  and its dependence on fundamental stellar parameters such as effective
  temperature and rotation. <BR /> Aims: We compile a chromospheric
  activity catalogue of 4454 cool stars from a combination of archival
  HARPS spectra and multiple other surveys, including the Mount Wilson
  data that have recently been released by the NSO. We explore the
  variation in chromospheric activity of cool stars along the main
  sequence for stars with different effective temperatures. Additionally,
  we also perform an activity-cycle period search and investigate its
  relation with rotation. <BR /> Methods: The chromospheric activity
  index, S-index, was measured for 304 main-sequence stars from
  archived high-resolution HARPS spectra. Additionally, the measured
  and archived S-indices were converted into the chromospheric flux
  ratio log R<SUB>HK</SUB><SUP>'</SUP>. The activity-cycle periods were
  determined using the generalised Lomb-Scargle periodogram to study
  the active and inactive branches on the rotation - activity-cycle
  period plane. <BR /> Results: The global sample shows that the
  bimodality of chromospheric activity, known as the Vaughan-Preston
  gap, is not prominent, with a significant percentage of the stars at
  an intermediate-activity level around R<SUP>'</SUP><SUB>HK</SUB> =
  -4.75. Independently, the cycle period search shows that stars can lie
  in the region intermediate between the active and inactive branch, which
  means that the active branch is not as clearly distinct as previously
  thought. <BR /> Conclusions: The weakening of the Vaughan-Preston
  gap indicates that cool stars spin down from a higher activity
  level and settle at a lower activity level without a sudden break
  at intermediate activity. Some cycle periods are close to the solar
  value between the active and inactive branch, which suggests that the
  solar dynamo is most likely a common case of the stellar dynamo. <P
  />Full Table A.1 is only available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A> (<A
  href="http://cdsarc.u-strasbg.fr">http://130.79.128.5</A>) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/616/A108">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/616/A108</A>

Title: VizieR Online Data Catalog: Cool stars chromospheric activity
    catalog (Boro Saikia+, 2018)
Authors: Boro Saikia, S.; Marvin, C. J.; Jeffers, S. V.; Reiners,
   A.; Cameron, R.; Marsden, S. C.; Petit, P.; Warnecke, J.; Yadav, A. P.
Bibcode: 2018yCat..36160108B
Altcode:
  We tabulate chromospheric activity of cool stars determined from
  CaII H and K lines. The catalogue is created by combining archival
  HARPS spectra (Lovis et al. 2011, Cat. J/A+A/528/112, Bonfils et
  al. 2013A&amp;A...549A.109B) and multiple other surveys (Baliunas
  et al. 1995ApJ...438..269B, Duncan et al. 1991ApJS...76..383D,
  Cat. III/159, Arriagada et al. 2012, Cat. J/ApJS/200/15, Henry et
  al. 1996, Cat. J/AJ/111/439, Gray et al. 2006, Cat. J/AJ/132/161, Hall
  et al. 2009, Cat. J/AJ/138/312, Wright et al. 2004, Cat. J/ApJS/152/261,
  Issacson &amp; Fischer 2010, Cat. J/ApJ/725/875). The stellar properties
  are taken from HIPPARCOS (Cat. I/239). <P />(1 data file).

Title: Observing and modeling the poloidal and toroidal fields of
    the solar dynamo
Authors: Cameron, R. H.; Duvall, T. L.; Schüssler, M.; Schunker, H.
Bibcode: 2018A&A...609A..56C
Altcode: 2017arXiv171007126C
  Context. The solar dynamo consists of a process that converts poloidal
  magnetic field to toroidal magnetic field followed by a process that
  creates new poloidal field from the toroidal field. <BR /> Aims:
  Our aim is to observe the poloidal and toroidal fields relevant to
  the global solar dynamo and to see if their evolution is captured by
  a Babcock-Leighton dynamo. <BR /> Methods: We used synoptic maps of
  the surface radial field from the KPNSO/VT and SOLIS observatories,
  to construct the poloidal field as a function of time and latitude; we
  also used full disk images from Wilcox Solar Observatory and SOHO/MDI
  to infer the longitudinally averaged surface azimuthal field. We show
  that the latter is consistent with an estimate of the longitudinally
  averaged surface azimuthal field due to flux emergence and therefore
  is closely related to the subsurface toroidal field. <BR /> Results: We
  present maps of the poloidal and toroidal magnetic fields of the global
  solar dynamo. The longitude-averaged azimuthal field observed at the
  surface results from flux emergence. At high latitudes this component
  follows the radial component of the polar fields with a short time
  lag of between 1-3 years. The lag increases at lower latitudes. The
  observed evolution of the poloidal and toroidal magnetic fields is
  described by the (updated) Babcock-Leighton dynamo model.

Title: The Global Solar Dynamo
Authors: Cameron, R. H.; Dikpati, M.; Brandenburg, A.
Bibcode: 2018smf..book..367C
Altcode:
  No abstract at ADS

Title: The Fermi Large Area Telescope: 9 years of on-orbit performance
Authors: Cameron, R.; Fermi Large Area Telescope Collaboration
Bibcode: 2017ifs..confE.128C
Altcode: 2017PoS...312E.128C
  No abstract at ADS

Title: The Global Solar Dynamo
Authors: Cameron, R. H.; Dikpati, M.; Brandenburg, A.
Bibcode: 2017SSRv..210..367C
Altcode: 2016arXiv160201754C; 2016SSRv..tmp....5C
  A brief summary of the various observations and constraints
  that underlie solar dynamo research are presented. The arguments
  that indicate that the solar dynamo is an alpha-omega dynamo of
  the Babcock-Leighton type are then shortly reviewed. The main open
  questions that remain are concerned with the subsurface dynamics,
  including why sunspots emerge at preferred latitudes as seen in
  the familiar butterfly wings, why the cycle is about 11 years long,
  and why the sunspot groups emerge tilted with respect to the equator
  (Joy's law). Next, we turn to magnetic helicity, whose conservation
  property has been identified with the decline of large-scale magnetic
  fields found in direct numerical simulations at large magnetic Reynolds
  numbers. However, magnetic helicity fluxes through the solar surface
  can alleviate this problem and connect theory with observations,
  as will be discussed.

Title: Cherenkov Telescope Array Contributions to the 35th
    International Cosmic Ray Conference (ICRC2017)
Authors: Acero, F.; Acharya, B. S.; Acín Portella, V.; Adams, C.;
   Agudo, I.; Aharonian, F.; Samarai, I. Al; Alberdi, A.; Alcubierre,
   M.; Alfaro, R.; Alfaro, J.; Alispach, C.; Aloisio, R.; Alves Batista,
   R.; Amans, J. -P.; Amato, E.; Ambrogi, L.; Ambrosi, G.; Ambrosio, M.;
   Anderson, J.; Anduze, M.; Angüner, E. O.; Antolini, E.; Antonelli,
   L. A.; Antonuccio, V.; Antoranz, P.; Aramo, C.; Araya, M.; Arcaro, C.;
   Armstrong, T.; Arqueros, F.; Arrabito, L.; Arrieta, M.; Asano, K.;
   Asano, A.; Ashley, M.; Aubert, P.; Singh, C. B.; Babic, A.; Backes,
   M.; Bajtlik, S.; Balazs, C.; Balbo, M.; Ballester, O.; Ballet, J.;
   Ballo, L.; Balzer, A.; Bamba, A.; Bandiera, R.; Barai, P.; Barbier,
   C.; Barcelo, M.; Barkov, M.; Barres de Almeida, U.; Barrio, J. A.;
   Bastieri, D.; Bauer, C.; Becciani, U.; Becherini, Y.; Becker Tjus,
   J.; Bednarek, W.; Belfiore, A.; Benbow, W.; Benito, M.; Berge, D.;
   Bernardini, E.; Bernardini, M. G.; Bernardos, M.; Bernhard, S.;
   Bernlöhr, K.; Bertinelli Salucci, C.; Bertucci, B.; Besel, M. -A.;
   Beshley, V.; Bettane, J.; Bhatt, N.; Bhattacharyya, W.; Bhattachryya,
   S.; Biasuzzi, B.; Bicknell, G.; Bigongiari, C.; Biland, A.; Bilinsky,
   A.; Bird, R.; Bissaldi, E.; Biteau, J.; Bitossi, M.; Blanch, O.;
   Blasi, P.; Blazek, J.; Boccato, C.; Bockermann, C.; Boehm, C.;
   Bohacova, M.; Boisson, C.; Bolmont, J.; Bonanno, G.; Bonardi, A.;
   Bonavolontà, C.; Bonnoli, G.; Borkowski, J.; Bose, R.; Bosnjak,
   Z.; Böttcher, M.; Boutonnet, C.; Bouyjou, F.; Bowman, L.; Bozhilov,
   V.; Braiding, C.; Brau-Nogué, S.; Bregeon, J.; Briggs, M.; Brill,
   A.; Brisken, W.; Bristow, D.; Britto, R.; Brocato, E.; Brown, A. M.;
   Brown, S.; Brügge, K.; Brun, P.; Brun, P.; Brun, F.; Brunetti, L.;
   Brunetti, G.; Bruno, P.; Bryan, M.; Buckley, J.; Bugaev, V.; Bühler,
   R.; Bulgarelli, A.; Bulik, T.; Burton, M.; Burtovoi, A.; Busetto, G.;
   Buson, S.; Buss, J.; Byrum, K.; Caccianiga, A.; Cameron, R.; Canelli,
   F.; Canestrari, R.; Capalbi, M.; Capasso, M.; Capitanio, F.; Caproni,
   A.; Capuzzo-Dolcetta, R.; Caraveo, P.; Cárdenas, V.; Cardenzana,
   J.; Cardillo, M.; Carlile, C.; Caroff, S.; Carosi, R.; Carosi, A.;
   Carquín, E.; Carr, J.; Casandjian, J. -M.; Casanova, S.; Cascone, E.;
   Castro-Tirado, A. J.; Castroviejo Mora, J.; Catalani, F.; Catalano, O.;
   Cauz, D.; Celestino Silva, C.; Celli, S.; Cerruti, M.; Chabanne, E.;
   Chadwick, P.; Chakraborty, N.; Champion, C.; Chatterjee, A.; Chaty, S.;
   Chaves, R.; Chen, A.; Chen, X.; Cheng, K.; Chernyakova, M.; Chikawa,
   M.; Chitnis, V. R.; Christov, A.; Chudoba, J.; Cieślar, M.; Clark,
   P.; Coco, V.; Colafrancesco, S.; Colin, P.; Colombo, E.; Colome, J.;
   Colonges, S.; Conforti, V.; Connaughton, V.; Conrad, J.; Contreras,
   J. L.; Cornat, R.; Cortina, J.; Costa, A.; Costantini, H.; Cotter, G.;
   Courty, B.; Covino, S.; Covone, G.; Cristofari, P.; Criswell, S. J.;
   Crocker, R.; Croston, J.; Crovari, C.; Cuadra, J.; Cuevas, O.; Cui,
   X.; Cumani, P.; Cusumano, G.; D'Aì, A.; D'Ammando, F.; D'Avanzo,
   P.; D'Urso, D.; Da Vela, P.; Dale, Ø.; Dang, V. T.; Dangeon, L.;
   Daniel, M.; Davids, I.; Dawson, B.; Dazzi, F.; De Angelis, A.; De
   Caprio, V.; de Cássia dos Anjos, R.; De Cesare, G.; De Franco, A.;
   De Frondat, F.; de Gouveia Dal Pino, E. M.; de la Calle, I.; De Lisio,
   C.; de los Reyes Lopez, R.; De Lotto, B.; De Luca, A.; De Lucia, M.;
   de Mello Neto, J. R. T.; de Naurois, M.; de Oña Wilhelmi, E.; De
   Palma, F.; De Persio, F.; de Souza, V.; Decock, J.; Deil, C.; Deiml,
   P.; Del Santo, M.; Delagnes, E.; Deleglise, G.; Delfino Reznicek, M.;
   Delgado, C.; Delgado Mengual, J.; Della Ceca, R.; della Volpe, D.;
   Detournay, M.; Devin, J.; Di Girolamo, T.; Di Giulio, C.; Di Pierro,
   F.; Di Venere, L.; Diaz, L.; Díaz, C.; Dib, C.; Dickinson, H.;
   Diebold, S.; Digel, S.; Djannati-Ataï, A.; Doert, M.; Domínguez,
   A.; Dominis Prester, D.; Donnarumma, I.; Dorner, D.; Doro, M.;
   Dournaux, J. -L.; Downes, T.; Drake, G.; Drappeau, S.; Drass, H.;
   Dravins, D.; Drury, L.; Dubus, G.; Dundas Morå, K.; Durkalec, A.;
   Dwarkadas, V.; Ebr, J.; Eckner, C.; Edy, E.; Egberts, K.; Einecke,
   S.; Eisch, J.; Eisenkolb, F.; Ekoume, T. R. N.; Eleftheriadis, C.;
   Elsässer, D.; Emmanoulopoulos, D.; Ernenwein, J. -P.; Escarate,
   P.; Eschbach, S.; Espinoza, C.; Evans, P.; Evoli, C.; Fairbairn, M.;
   Falceta-Goncalves, D.; Falcone, A.; Fallah Ramazani, V.; Farakos, K.;
   Farrell, E.; Fasola, G.; Favre, Y.; Fede, E.; Fedora, R.; Fedorova,
   E.; Fegan, S.; Fernandez-Alonso, M.; Fernández-Barral, A.; Ferrand,
   G.; Ferreira, O.; Fesquet, M.; Fiandrini, E.; Fiasson, A.; Filipovic,
   M.; Fink, D.; Finley, J. P.; Finley, C.; Finoguenov, A.; Fioretti,
   V.; Fiorini, M.; Flores, H.; Foffano, L.; Föhr, C.; Fonseca, M. V.;
   Font, L.; Fontaine, G.; Fornasa, M.; Fortin, P.; Fortson, L.; Fouque,
   N.; Fraga, B.; Franco, F. J.; Freixas Coromina, L.; Fruck, C.; Fugazza,
   D.; Fujita, Y.; Fukami, S.; Fukazawa, Y.; Fukui, Y.; Funk, S.; Furniss,
   A.; Füßling, M.; Gabici, S.; Gadola, A.; Gallant, Y.; Galloway, D.;
   Gallozzi, S.; Garcia, B.; Garcia, A.; García Gil, R.; Garcia López,
   R.; Garczarczyk, M.; Gardiol, D.; Gargano, F.; Gargano, C.; Garozzo,
   S.; Garrido-Ruiz, M.; Gascon, D.; Gasparetto, T.; Gaté, F.; Gaug,
   M.; Gebhardt, B.; Gebyehu, M.; Geffroy, N.; Genolini, B.; Ghalumyan,
   A.; Ghedina, A.; Ghirlanda, G.; Giammaria, P.; Gianotti, F.; Giebels,
   B.; Giglietto, N.; Gika, V.; Gimenes, R.; Giommi, P.; Giordano, F.;
   Giovannini, G.; Giro, E.; Giroletti, M.; Gironnet, J.; Giuliani, A.;
   Glicenstein, J. -F.; Gnatyk, R.; Godinovic, N.; Goldoni, P.; Gómez,
   J. L.; Gómez-Vargas, G.; González, M. M.; González, J. M.; Gothe,
   K. S.; Gotz, D.; Goullon, J.; Grabarczyk, T.; Graciani, R.; Graham,
   J.; Grandi, P.; Granot, J.; Grasseau, G.; Gredig, R.; Green, A. J.;
   Greenshaw, T.; Grenier, I.; Griffiths, S.; Grillo, A.; Grondin, M. -H.;
   Grube, J.; Guarino, V.; Guest, B.; Gueta, O.; Gunji, S.; Gyuk, G.;
   Hadasch, D.; Hagge, L.; Hahn, J.; Hahn, A.; Hakobyan, H.; Hara, S.;
   Hardcastle, M. J.; Hassan, T.; Haubold, T.; Haupt, A.; Hayashi, K.;
   Hayashida, M.; He, H.; Heller, M.; Helo, J. C.; Henault, F.; Henri, G.;
   Hermann, G.; Hermel, R.; Herrera Llorente, J.; Herrero, A.; Hervet, O.;
   Hidaka, N.; Hinton, J.; Hiroshima, N.; Hirotani, K.; Hnatyk, B.; Hoang,
   J. K.; Hoffmann, D.; Hofmann, W.; Holder, J.; Horan, D.; Hörandel,
   J.; Hörbe, M.; Horns, D.; Horvath, P.; Houles, J.; Hovatta, T.;
   Hrabovsky, M.; Hrupec, D.; Huet, J. -M.; Hughes, G.; Hui, D.; Hull,
   G.; Humensky, T. B.; Hussein, M.; Hütten, M.; Iarlori, M.; Ikeno,
   Y.; Illa, J. M.; Impiombato, D.; Inada, T.; Ingallinera, A.; Inome,
   Y.; Inoue, S.; Inoue, T.; Inoue, Y.; Iocco, F.; Ioka, K.; Ionica,
   M.; Iori, M.; Iriarte, A.; Ishio, K.; Israel, G. L.; Iwamura, Y.;
   Jablonski, C.; Jacholkowska, A.; Jacquemier, J.; Jamrozy, M.; Janecek,
   P.; Jankowsky, F.; Jankowsky, D.; Jansweijer, P.; Jarnot, C.; Jean, P.;
   Johnson, C. A.; Josselin, M.; Jung-Richardt, I.; Jurysek, J.; Kaaret,
   P.; Kachru, P.; Kagaya, M.; Kakuwa, J.; Kalekin, O.; Kankanyan, R.;
   Karastergiou, A.; Karczewski, M.; Karkar, S.; Katagiri, H.; Kataoka,
   J.; Katarzyński, K.; Katz, U.; Kawanaka, N.; Kaye, L.; Kazanas, D.;
   Kelley-Hoskins, N.; Khélifi, B.; Kieda, D. B.; Kihm, T.; Kimeswenger,
   S.; Kimura, S.; Kisaka, S.; Kishida, S.; Kissmann, R.; Kluźniak, W.;
   Knapen, J.; Knapp, J.; Knödlseder, J.; Koch, B.; Kocot, J.; Kohri,
   K.; Komin, N.; Kong, A.; Konno, Y.; Kosack, K.; Kowal, G.; Koyama,
   S.; Kraus, M.; Krause, M.; Krauß, F.; Krennrich, F.; Kruger, P.;
   Kubo, H.; Kudryavtsev, V.; Kukec Mezek, G.; Kumar, S.; Kuroda, H.;
   Kushida, J.; Kushwaha, P.; La Palombara, N.; La Parola, V.; La Rosa,
   G.; Lahmann, R.; Lalik, K.; Lamanna, G.; Landoni, M.; Landriu, D.;
   Landt, H.; Lang, R. G.; Lapington, J.; Laporte, P.; Le Blanc, O.;
   Le Flour, T.; Le Sidaner, P.; Leach, S.; Leckngam, A.; Lee, S. -H.;
   Lee, W. H.; Lees, J. -P.; Lefaucheur, J.; Leigui de Oliveira, M. A.;
   Lemoine-Goumard, M.; Lenain, J. -P.; Leto, G.; Lico, R.; Limon, M.;
   Lindemann, R.; Lindfors, E.; Linhoff, L.; Lipniacka, A.; Lloyd, S.;
   Lohse, T.; Lombardi, S.; Longo, F.; Lopez, M.; Lopez-Coto, R.; Louge,
   T.; Louis, F.; Louys, M.; Lucarelli, F.; Lucchesi, D.; Luque-Escamilla,
   P. L.; Lyard, E.; Maccarone, M. C.; Maccarone, T.; Mach, E.; Madejski,
   G. M.; Maier, G.; Majczyna, A.; Majumdar, P.; Makariev, M.; Malaguti,
   G.; Malouf, A.; Maltezos, S.; Malyshev, D.; Malyshev, D.; Mandat,
   D.; Maneva, G.; Manganaro, M.; Mangano, S.; Manigot, P.; Mannheim,
   K.; Maragos, N.; Marano, D.; Marcowith, A.; Marín, J.; Mariotti,
   M.; Marisaldi, M.; Markoff, S.; Martí, J.; Martin, J. -M.; Martin,
   P.; Martin, L.; Martínez, M.; Martínez, G.; Martínez, O.; Marx,
   R.; Masetti, N.; Massimino, P.; Mastichiadis, A.; Mastropietro, M.;
   Masuda, S.; Matsumoto, H.; Matthews, N.; Mattiazzo, S.; Maurin, G.;
   Maxted, N.; Mayer, M.; Mazin, D.; Mazziotta, M. N.; Mc Comb, L.;
   McHardy, I.; Medina, C.; Melandri, A.; Melioli, C.; Melkumyan, D.;
   Mereghetti, S.; Meunier, J. -L.; Meures, T.; Meyer, M.; Micanovic, S.;
   Michael, T.; Michałowski, J.; Mievre, I.; Miller, J.; Minaya, I. A.;
   Mineo, T.; Mirabel, F.; Miranda, J. M.; Mirzoyan, R.; Mitchell, A.;
   Mizuno, T.; Moderski, R.; Mohammed, M.; Mohrmann, L.; Molijn, C.;
   Molinari, E.; Moncada, R.; Montaruli, T.; Monteiro, I.; Mooney, D.;
   Moore, P.; Moralejo, A.; Morcuende-Parrilla, D.; Moretti, E.; Mori,
   K.; Morlino, G.; Morris, P.; Morselli, A.; Moscato, F.; Motohashi,
   D.; Moulin, E.; Mueller, S.; Mukherjee, R.; Munar, P.; Mundell, C.;
   Mundet, J.; Murach, T.; Muraishi, H.; Murase, K.; Murphy, A.; Nagai,
   A.; Nagar, N.; Nagataki, S.; Nagayoshi, T.; Nagesh, B. K.; Naito,
   T.; Nakajima, D.; Nakamori, T.; Nakamura, Y.; Nakayama, K.; Naumann,
   D.; Nayman, P.; Neise, D.; Nellen, L.; Nemmen, R.; Neronov, A.;
   Neyroud, N.; Nguyen, T.; Nguyen, T. T.; Nguyen Trung, T.; Nicastro,
   L.; Nicolau-Kukliński, J.; Niemiec, J.; Nieto, D.; Nievas-Rosillo,
   M.; Nikołajuk, M.; Nishijima, K.; Nishikawa, K. -I.; Nishiyama, G.;
   Noda, K.; Nogues, L.; Nolan, S.; Nosek, D.; Nöthe, M.; Novosyadlyj,
   B.; Nozaki, S.; Nunio, F.; O'Brien, P.; Oakes, L.; Ocampo, C.; Ochoa,
   J. P.; Oger, R.; Ohira, Y.; Ohishi, M.; Ohm, S.; Okazaki, N.; Okumura,
   A.; Olive, J. -F.; Ong, R. A.; Orienti, M.; Orito, R.; Orlati, A.;
   Osborne, J. P.; Ostrowski, M.; Otte, N.; Ou, Z.; Ovcharov, E.; Oya,
   I.; Ozieblo, A.; Padovani, M.; Paiano, S.; Paizis, A.; Palacio, J.;
   Palatiello, M.; Palatka, M.; Pallotta, J.; Panazol, J. -L.; Paneque,
   D.; Panter, M.; Paoletti, R.; Paolillo, M.; Papitto, A.; Paravac, A.;
   Paredes, J. M.; Pareschi, G.; Parsons, R. D.; Paśko, P.; Pavy, S.;
   Pe'er, A.; Pech, M.; Pedaletti, G.; Peñil Del Campo, P.; Perez, A.;
   Pérez-Torres, M. A.; Perri, L.; Perri, M.; Persic, M.; Petrashyk,
   A.; Petrera, S.; Petrucci, P. -O.; Petruk, O.; Peyaud, B.; Pfeifer,
   M.; Piano, G.; Piel, Q.; Pieloth, D.; Pintore, F.; García, C. Pio;
   Pisarski, A.; Pita, S.; Pizarro, L.; Platos, Ł.; Pohl, M.; Poireau,
   V.; Pollo, A.; Porthault, J.; Poutanen, J.; Pozo, D.; Prandini, E.;
   Prasit, P.; Prast, J.; Pressard, K.; Principe, G.; Prokhorov, D.;
   Prokoph, H.; Prouza, M.; Pruteanu, G.; Pueschel, E.; Pühlhofer,
   G.; Puljak, I.; Punch, M.; Pürckhauer, S.; Queiroz, F.; Quinn, J.;
   Quirrenbach, A.; Rafighi, I.; Rainò, S.; Rajda, P. J.; Rando, R.;
   Rannot, R. C.; Razzaque, S.; Reichardt, I.; Reimer, O.; Reimer, A.;
   Reisenegger, A.; Renaud, M.; Reposeur, T.; Reville, B.; Rezaeian,
   A. H.; Rhode, W.; Ribeiro, D.; Ribó, M.; Richer, M. G.; Richtler,
   T.; Rico, J.; Rieger, F.; Riquelme, M.; Ristori, P. R.; Rivoire, S.;
   Rizi, V.; Rodriguez, J.; Rodriguez Fernandez, G.; Rodríguez Vázquez,
   J. J.; Rojas, G.; Romano, P.; Romeo, G.; Roncadelli, M.; Rosado, J.;
   Rosen, S.; Rosier Lees, S.; Rousselle, J.; Rovero, A. C.; Rowell, G.;
   Rudak, B.; Rugliancich, A.; Ruíz del Mazo, J. E.; Rujopakarn, W.;
   Rulten, C.; Russo, F.; Saavedra, O.; Sabatini, S.; Sacco, B.; Sadeh,
   I.; Sæther Hatlen, E.; Safi-Harb, S.; Sahakian, V.; Sailer, S.; Saito,
   T.; Sakaki, N.; Sakurai, S.; Salek, D.; Salesa Greus, F.; Salina, G.;
   Sanchez, D.; Sánchez-Conde, M.; Sandaker, H.; Sandoval, A.; Sangiorgi,
   P.; Sanguillon, M.; Sano, H.; Santander, M.; Santangelo, A.; Santos,
   E. M.; Sanuy, A.; Sapozhnikov, L.; Sarkar, S.; Satalecka, K.; Sato,
   Y.; Saturni, F. G.; Savalle, R.; Sawada, M.; Schanne, S.; Schioppa,
   E. J.; Schlenstedt, S.; Schmidt, T.; Schmoll, J.; Schneider, M.;
   Schoorlemmer, H.; Schovanek, P.; Schulz, A.; Schussler, F.; Schwanke,
   U.; Schwarz, J.; Schweizer, T.; Schwemmer, S.; Sciacca, E.; Scuderi,
   S.; Seglar-Arroyo, M.; Segreto, A.; Seitenzahl, I.; Semikoz, D.;
   Sergijenko, O.; Serre, N.; Servillat, M.; Seweryn, K.; Shah, K.;
   Shalchi, A.; Sharma, M.; Shellard, R. C.; Shilon, I.; Sidoli, L.;
   Sidz, M.; Siejkowski, H.; Silk, J.; Sillanpää, A.; Simone, D.; Singh,
   B. B.; Sironi, G.; Sitarek, J.; Sizun, P.; Sliusar, V.; Slowikowska,
   A.; Smith, A.; Sobczyńska, D.; Sokolenko, A.; Sol, H.; Sottile, G.;
   Springer, W.; Stahl, O.; Stamerra, A.; Stanič, S.; Starling, R.;
   Staszak, D.; Stawarz, Ł.; Steenkamp, R.; Stefanik, S.; Stegmann,
   C.; Steiner, S.; Stella, C.; Stephan, M.; Sternberger, R.; Sterzel,
   M.; Stevenson, B.; Stodulska, M.; Stodulski, M.; Stolarczyk, T.;
   Stratta, G.; Straumann, U.; Stuik, R.; Suchenek, M.; Suomijarvi, T.;
   Supanitsky, A. D.; Suric, T.; Sushch, I.; Sutcliffe, P.; Sykes, J.;
   Szanecki, M.; Szepieniec, T.; Tagliaferri, G.; Tajima, H.; Takahashi,
   K.; Takahashi, H.; Takahashi, M.; Takalo, L.; Takami, S.; Takata, J.;
   Takeda, J.; Tam, T.; Tanaka, M.; Tanaka, T.; Tanaka, Y.; Tanaka, S.;
   Tanci, C.; Tavani, M.; Tavecchio, F.; Tavernet, J. -P.; Tayabaly,
   K.; Tejedor, L. A.; Temme, F.; Temnikov, P.; Terada, Y.; Terrazas,
   J. C.; Terrier, R.; Terront, D.; Terzic, T.; Tescaro, D.; Teshima, M.;
   Testa, V.; Thoudam, S.; Tian, W.; Tibaldo, L.; Tiengo, A.; Tiziani, D.;
   Tluczykont, M.; Todero Peixoto, C. J.; Tokanai, F.; Tokarz, M.; Toma,
   K.; Tomastik, J.; Tonachini, A.; Tonev, D.; Tornikoski, M.; Torres,
   D. F.; Torresi, E.; Tosti, G.; Totani, T.; Tothill, N.; Toussenel,
   F.; Tovmassian, G.; Trakarnsirinont, N.; Travnicek, P.; Trichard,
   C.; Trifoglio, M.; Troyano Pujadas, I.; Tsirou, M.; Tsujimoto,
   S.; Tsuru, T.; Uchiyama, Y.; Umana, G.; Uslenghi, M.; Vagelli, V.;
   Vagnetti, F.; Valentino, M.; Vallania, P.; Valore, L.; Van den Berg,
   A. M.; van Driel, W.; van Eldik, C.; van Soelen, B.; Vandenbroucke,
   J.; Vanderwalt, J.; Varner, G. S.; Vasileiadis, G.; Vassiliev, V.;
   Vázquez, J. R.; Vázquez Acosta, M.; Vecchi, M.; Vega, A.; Veitch,
   P.; Venault, P.; Venter, C.; Vercellone, S.; Veres, P.; Vergani,
   S.; Verzi, V.; Vettolani, G. P.; Veyssiere, C.; Viana, A.; Vicha,
   J.; Vigorito, C.; Villanueva, J.; Vincent, P.; Vink, J.; Visconti,
   F.; Vittorini, V.; Voelk, H.; Voisin, V.; Vollhardt, A.; Vorobiov,
   S.; Vovk, I.; Vrastil, M.; Vuillaume, T.; Wagner, S. J.; Wagner, R.;
   Wagner, P.; Wakely, S. P.; Walstra, T.; Walter, R.; Ward, M.; Ward,
   J. E.; Warren, D.; Watson, J. J.; Webb, N.; Wegner, P.; Weiner, O.;
   Weinstein, A.; Weniger, C.; Werner, F.; Wetteskind, H.; White, M.;
   White, R.; Wierzcholska, A.; Wiesand, S.; Wijers, R.; Wilcox, P.;
   Wilhelm, A.; Wilkinson, M.; Will, M.; Williams, D. A.; Winter, M.;
   Wojcik, P.; Wolf, D.; Wood, M.; Wörnlein, A.; Wu, T.; Yadav, K. K.;
   Yaguna, C.; Yamamoto, T.; Yamamoto, H.; Yamane, N.; Yamazaki, R.;
   Yanagita, S.; Yang, L.; Yelos, D.; Yoshida, T.; Yoshida, M.; Yoshiike,
   S.; Yoshikoshi, T.; Yu, P.; Zaborov, D.; Zacharias, M.; Zaharijas, G.;
   Zajczyk, A.; Zampieri, L.; Zandanel, F.; Zanin, R.; Zanmar Sanchez,
   R.; Zaric, D.; Zavrtanik, M.; Zavrtanik, D.; Zdziarski, A. A.; Zech,
   A.; Zechlin, H.; Zhdanov, V. I.; Ziegler, A.; Ziemann, J.; Ziętara,
   K.; Zink, A.; Ziółkowski, J.; Zitelli, V.; Zoli, A.; Zorn, J.
Bibcode: 2017arXiv170903483A
Altcode: 2017arXiv170903483C
  List of contributions from the Cherenkov Telescope Array Consortium
  presented at the 35th International Cosmic Ray Conference, July 12-20
  2017, Busan, Korea.

Title: Observing and modelling the poloidal and toroidal magnetic
    fields of the global dynamo
Authors: Cameron, Robert; Duvall, Thomas; Schüssler, Manfred;
   Schunker, Hannah
Bibcode: 2017SPD....4830601C
Altcode:
  The large scale solar dynamo is a cycle where poloidal flux is
  generated from toroidal flux, and toroidal flux is generated from
  poloidal flux. The toroidal and poloidal fields can be inferred from
  observations, and the Babcock-Leighton model shows how differential
  rotation and flux emergence explain the observed evolution of the
  fields.

Title: The nature of solar brightness variations
Authors: Shapiro, A. I.; Solanki, S. K.; Krivova, N. A.; Cameron,
   R. H.; Yeo, K. L.; Schmutz, W. K.
Bibcode: 2017NatAs...1..612S
Altcode: 2017arXiv171104156S
  Determining the sources of solar brightness variations<SUP>1,2</SUP>,
  often referred to as solar noise<SUP>3</SUP>, is important because
  solar noise limits the detection of solar oscillations<SUP>3</SUP>,
  is one of the drivers of the Earth's climate system<SUP>4,5</SUP> and
  is a prototype of stellar variability<SUP>6,7</SUP>—an important
  limiting factor for the detection of extrasolar planets. Here,
  we model the magnetic contribution to solar brightness variability
  using high-cadence<SUP>8,9</SUP> observations from the Solar Dynamics
  Observatory (SDO) and the Spectral And Total Irradiance REconstruction
  (SATIRE)<SUP>10,11</SUP> model. The brightness variations caused by
  the constantly evolving cellular granulation pattern on the solar
  surface were computed with the Max Planck Institute for Solar System
  Research (MPS)/University of Chicago Radiative Magnetohydrodynamics
  (MURaM)<SUP>12</SUP> code. We found that the surface magnetic field
  and granulation can together precisely explain solar noise (that
  is, solar variability excluding oscillations) on timescales from
  minutes to decades, accounting for all timescales that have so far
  been resolved or covered by irradiance measurements. We demonstrate
  that no other sources of variability are required to explain the
  data. Recent measurements of Sun-like stars by the COnvection ROtation
  and planetary Transits (CoRoT)<SUP>13</SUP> and Kepler<SUP>14</SUP>
  missions uncovered brightness variations similar to that of the Sun,
  but with a much wider variety of patterns<SUP>15</SUP>. Our finding
  that solar brightness variations can be replicated in detail with
  just two well-known sources will greatly simplify future modelling of
  existing CoRoT and Kepler as well as anticipated Transiting Exoplanet
  Survey Satellite<SUP>16</SUP> and PLAnetary Transits and Oscillations
  of stars (PLATO)<SUP>17</SUP> data.

Title: Evidence for photometric activity cycles in 3203 Kepler stars
Authors: Reinhold, Timo; Cameron, Robert H.; Gizon, Laurent
Bibcode: 2017A&A...603A..52R
Altcode: 2017arXiv170503312R
  Context. In recent years it has been claimed that the length of stellar
  activity cycles is determined by the stellar rotation rate. It has been
  observed that the cycle period increases with rotation period along
  two distinct sequences, known as the active and inactive sequences. In
  this picture the Sun occupies a solitary position between the two
  sequences. Whether the Sun might undergo a transitional evolutionary
  stage is currently under debate. <BR /> Aims: Our goal is to measure
  cyclic variations of the stellar light curve amplitude and the rotation
  period using four years of Kepler data. Periodic changes in the light
  curve amplitude or the stellar rotation period are associated with
  an underlying activity cycle. <BR /> Methods: Using a recent sample
  of active stars we compute the rotation period and the variability
  amplitude for each individual Kepler quarter and search for periodic
  variations of both time series. To test for periodicity in each
  stellar time series we consider Lomb-Scargle periodograms and use a
  selection based on a false alarm probability (FAP). <BR /> Results:
  We detect amplitude periodicities in 3203 stars between 0.5 &lt;
  P<SUB>cyc</SUB> &lt; 6 yr covering rotation periods between 1 &lt;
  P<SUB>rot</SUB> &lt; 40 days. Given our sample size of 23 601 stars
  and our selection criteria that the FAP is less than 5%, this number
  is almost three times higher than that expected from pure noise. We do
  not detect periodicities in the rotation period beyond those expected
  from noise. Our measurements reveal that the cycle period shows a weak
  dependence on rotation rate, slightly increasing for longer rotation
  periods. We further show that the shape of the variability deviates from
  a pure sine curve, consistent with observations of the solar cycle. The
  cycle shape does not show a statistically significant dependence on
  effective temperature. <BR /> Conclusions: We detect activity cycles
  in more than 13% of our final sample with a FAP of 5% (calculated by
  randomly shuffling the measured 90-day variability measurements for
  each star). Our measurements do not support the existence of distinct
  sequences in the P<SUB>rot</SUB>-P<SUB>cyc</SUB> plane, although there
  is some evidence for the inactive sequence for rotation periods between
  5-25 days. Unfortunately, the total observing time is too short to draw
  sound conclusions on activity cycles with similar lengths to that of the
  solar cycle. <P />A table containing all cycle periods and time series
  is only available in electronic form at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
  (130.79.128.5) or via <A
  href="http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/603/A52">http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/603/A52</A>

Title: Understanding Solar Cycle Variability
Authors: Cameron, R. H.; Schüssler, M.
Bibcode: 2017ApJ...843..111C
Altcode: 2017arXiv170510746C
  The level of solar magnetic activity, as exemplified by the number
  of sunspots and by energetic events in the corona, varies on a wide
  range of timescales. Most prominent is the 11-year solar cycle,
  which is significantly modulated on longer timescales. Drawing from
  dynamo theory, together with the empirical results of past solar
  activity and similar phenomena for solar-like stars, we show that
  the variability of the solar cycle can be essentially understood in
  terms of a weakly nonlinear limit cycle affected by random noise. In
  contrast to ad hoc “toy models” for the solar cycle, this leads
  to a generic normal-form model, whose parameters are all constrained
  by observations. The model reproduces the characteristics of the
  variable solar activity on timescales between decades and millennia,
  including the occurrence and statistics of extended periods of very
  low activity (grand minima). Comparison with results obtained with
  a Babcock-Leighton-type dynamo model confirm the validity of the
  normal-mode approach.

Title: Effects of pH and Redox Gradients on Prebiotic Organic
    Synthesis and the Generation of Free Energy in Simulated Hydrothermal
    Systems
Authors: Barge, L. M.; Flores, E.; Abedian, Y.; Maltais, T.; Cameron,
   R.; Hermis, N.; Chin, K.; Russell, M. J.; Baum, M. M.
Bibcode: 2017LPICo1967.4179B
Altcode:
  Hydrothermal minerals in alkaline vents can promote phosphorus and
  organic concentration, redox reactions driven by catalytic metal
  sulfides, and the ambient pH and redox gradients can affect the
  synthesis of organics.

Title: Evolution of the Sun's non-axisymmetric toroidal field
Authors: Martin-Belda, D.; Cameron, R. H.
Bibcode: 2017A&A...603A..53M
Altcode: 2017arXiv170310075M
  <BR /> Aims: We aim to infer the sub-surface distribution of the Sun's
  non-axisymmetric azimuthal magnetic flux from observable quantities,
  such as the surface magnetic field and the large scale plasma flows. <BR
  /> Methods: We have built a kinematic flux transport model of the
  solar dynamo based on the Babcock-Leighton framework. We constructed
  the source term for the poloidal field using SOLIS magnetograms
  spanning three solar cycles. Based on this source we calculated the
  azimuthal flux below the surface. The flux transport model has two
  free parameters which we constrained using sunspot observations from
  cycle 22. We compared the model results with observations from cycle
  23. <BR /> Results: The structure of the azimuthal field is mainly
  axisymmetric. The departures from axisymmetry represent, on average,
  3% of the total azimuthal flux. Owing to its relative weakness, the
  non-axisymmetric structure of the azimuthal field does not have a
  significant impact on the location in which the emergences appear or
  on the amount of flux contained in them. We find that the probability
  of emergence is a function of the ratio between the flux content of
  an active region and the underlying azimuthal flux.

Title: VizieR Online Data Catalog: Activity cycles in 3203 Kepler
    stars (Reinhold+, 2017)
Authors: Reinhold, T.; Cameron, R. H.; Gizon, L.
Bibcode: 2017yCat..36030052R
Altcode:
  Rvar time series, sine fit parameters, mean rotation periods, and
  false alarm probabilities of all 3203 Kepler stars are presented. For
  simplicity, the KIC number and the fit parameters of a certain star
  are repeated in each line. The fit function to the Rvar(t) time
  series equals y_fit=Acyc*sin(2*pi/(Pcyc*365)*(t-t0))+Offset. <P />(2
  data files).

Title: Prospects for Cherenkov Telescope Array Observations of the
    Young Supernova Remnant RX J1713.7-3946
Authors: Acero, F.; Aloisio, R.; Amans, J.; Amato, E.; Antonelli,
   L. A.; Aramo, C.; Armstrong, T.; Arqueros, F.; Asano, K.; Ashley, M.;
   Backes, M.; Balazs, C.; Balzer, A.; Bamba, A.; Barkov, M.; Barrio,
   J. A.; Benbow, W.; Bernlöhr, K.; Beshley, V.; Bigongiari, C.; Biland,
   A.; Bilinsky, A.; Bissaldi, E.; Biteau, J.; Blanch, O.; Blasi, P.;
   Blazek, J.; Boisson, C.; Bonanno, G.; Bonardi, A.; Bonavolontà,
   C.; Bonnoli, G.; Braiding, C.; Brau-Nogué, S.; Bregeon, J.; Brown,
   A. M.; Bugaev, V.; Bulgarelli, A.; Bulik, T.; Burton, M.; Burtovoi,
   A.; Busetto, G.; Böttcher, M.; Cameron, R.; Capalbi, M.; Caproni, A.;
   Caraveo, P.; Carosi, R.; Cascone, E.; Cerruti, M.; Chaty, S.; Chen, A.;
   Chen, X.; Chernyakova, M.; Chikawa, M.; Chudoba, J.; Cohen-Tanugi, J.;
   Colafrancesco, S.; Conforti, V.; Contreras, J. L.; Costa, A.; Cotter,
   G.; Covino, S.; Covone, G.; Cumani, P.; Cusumano, G.; D'Ammando, F.;
   D'Urso, D.; Daniel, M.; Dazzi, F.; De Angelis, A.; De Cesare, G.;
   De Franco, A.; De Frondat, F.; de Gouveia Dal Pino, E. M.; De Lisio,
   C.; de los Reyes Lopez, R.; De Lotto, B.; de Naurois, M.; De Palma,
   F.; Del Santo, M.; Delgado, C.; della Volpe, D.; Di Girolamo, T.;
   Di Giulio, C.; Di Pierro, F.; Di Venere, L.; Doro, M.; Dournaux, J.;
   Dumas, D.; Dwarkadas, V.; Díaz, C.; Ebr, J.; Egberts, K.; Einecke,
   S.; Elsässer, D.; Eschbach, S.; Falceta-Goncalves, D.; Fasola,
   G.; Fedorova, E.; Fernández-Barral, A.; Ferrand, G.; Fesquet, M.;
   Fiandrini, E.; Fiasson, A.; Filipović, M. D.; Fioretti, V.; Font, L.;
   Fontaine, G.; Franco, F. J.; Freixas Coromina, L.; Fujita, Y.; Fukui,
   Y.; Funk, S.; Förster, A.; Gadola, A.; Garcia López, R.; Garczarczyk,
   M.; Giglietto, N.; Giordano, F.; Giuliani, A.; Glicenstein, J.; Gnatyk,
   R.; Goldoni, P.; Grabarczyk, T.; Graciani, R.; Graham, J.; Grandi,
   P.; Granot, J.; Green, A. J.; Griffiths, S.; Gunji, S.; Hakobyan, H.;
   Hara, S.; Hassan, T.; Hayashida, M.; Heller, M.; Helo, J. C.; Hinton,
   J.; Hnatyk, B.; Huet, J.; Huetten, M.; Humensky, T. B.; Hussein, M.;
   Hörandel, J.; Ikeno, Y.; Inada, T.; Inome, Y.; Inoue, S.; Inoue, T.;
   Inoue, Y.; Ioka, K.; Iori, M.; Jacquemier, J.; Janecek, P.; Jankowsky,
   D.; Jung, I.; Kaaret, P.; Katagiri, H.; Kimeswenger, S.; Kimura, S.;
   Knödlseder, J.; Koch, B.; Kocot, J.; Kohri, K.; Komin, N.; Konno, Y.;
   Kosack, K.; Koyama, S.; Kraus, M.; Kubo, H.; Kukec Mezek, G.; Kushida,
   J.; La Palombara, N.; Lalik, K.; Lamanna, G.; Landt, H.; Lapington,
   J.; Laporte, P.; Lee, S.; Lees, J.; Lefaucheur, J.; Lenain, J. -P.;
   Leto, G.; Lindfors, E.; Lohse, T.; Lombardi, S.; Longo, F.; Lopez,
   M.; Lucarelli, F.; Luque-Escamilla, P. L.; López-Coto, R.; Maccarone,
   M. C.; Maier, G.; Malaguti, G.; Mandat, D.; Maneva, G.; Mangano, S.;
   Marcowith, A.; Martí, J.; Martínez, M.; Martínez, G.; Masuda, S.;
   Maurin, G.; Maxted, N.; Melioli, C.; Mineo, T.; Mirabal, N.; Mizuno,
   T.; Moderski, R.; Mohammed, M.; Montaruli, T.; Moralejo, A.; Mori,
   K.; Morlino, G.; Morselli, A.; Moulin, E.; Mukherjee, R.; Mundell,
   C.; Muraishi, H.; Murase, K.; Nagataki, S.; Nagayoshi, T.; Naito,
   T.; Nakajima, D.; Nakamori, T.; Nemmen, R.; Niemiec, J.; Nieto, D.;
   Nievas-Rosillo, M.; Nikołajuk, M.; Nishijima, K.; Noda, K.; Nogues,
   L.; Nosek, D.; Novosyadlyj, B.; Nozaki, S.; Ohira, Y.; Ohishi, M.;
   Ohm, S.; Okumura, A.; Ong, R. A.; Orito, R.; Orlati, A.; Ostrowski,
   M.; Oya, I.; Padovani, M.; Palacio, J.; Palatka, M.; Paredes, J. M.;
   Pavy, S.; Pe'er, A.; Persic, M.; Petrucci, P.; Petruk, O.; Pisarski,
   A.; Pohl, M.; Porcelli, A.; Prandini, E.; Prast, J.; Principe, G.;
   Prouza, M.; Pueschel, E.; Pühlhofer, G.; Quirrenbach, A.; Rameez,
   M.; Reimer, O.; Renaud, M.; Ribó, M.; Rico, J.; Rizi, V.; Rodriguez,
   J.; Rodriguez Fernandez, G.; Rodríguez Vázquez, J. J.; Romano, P.;
   Romeo, G.; Rosado, J.; Rousselle, J.; Rowell, G.; Rudak, B.; Sadeh,
   I.; Safi-Harb, S.; Saito, T.; Sakaki, N.; Sanchez, D.; Sangiorgi,
   P.; Sano, H.; Santander, M.; Sarkar, S.; Sawada, M.; Schioppa,
   E. J.; Schoorlemmer, H.; Schovanek, P.; Schussler, F.; Sergijenko,
   O.; Servillat, M.; Shalchi, A.; Shellard, R. C.; Siejkowski, H.;
   Sillanpää, A.; Simone, D.; Sliusar, V.; Sol, H.; Stanič, S.;
   Starling, R.; Stawarz, Ł.; Stefanik, S.; Stephan, M.; Stolarczyk, T.;
   Szanecki, M.; Szepieniec, T.; Tagliaferri, G.; Tajima, H.; Takahashi,
   M.; Takeda, J.; Tanaka, M.; Tanaka, S.; Tejedor, L. A.; Telezhinsky,
   I.; Temnikov, P.; Terada, Y.; Tescaro, D.; Teshima, M.; Testa, V.;
   Thoudam, S.; Tokanai, F.; Torres, D. F.; Torresi, E.; Tosti, G.;
   Townsley, C.; Travnicek, P.; Trichard, C.; Trifoglio, M.; Tsujimoto,
   S.; Vagelli, V.; Vallania, P.; Valore, L.; van Driel, W.; van Eldik,
   C.; Vandenbroucke, J.; Vassiliev, V.; Vecchi, M.; Vercellone, S.;
   Vergani, S.; Vigorito, C.; Vorobiov, S.; Vrastil, M.; Vázquez
   Acosta, M. L.; Wagner, S. J.; Wagner, R.; Wakely, S. P.; Walter,
   R.; Ward, J. E.; Watson, J. J.; Weinstein, A.; White, M.; White, R.;
   Wierzcholska, A.; Wilcox, P.; Williams, D. A.; Wischnewski, R.; Wojcik,
   P.; Yamamoto, T.; Yamamoto, H.; Yamazaki, R.; Yanagita, S.; Yang, L.;
   Yoshida, T.; Yoshida, M.; Yoshiike, S.; Yoshikoshi, T.; Zacharias,
   M.; Zampieri, L.; Zanin, R.; Zavrtanik, M.; Zavrtanik, D.; Zdziarski,
   A.; Zech, A.; Zechlin, H.; Zhdanov, V.; Ziegler, A.; Zorn, J.
Bibcode: 2017ApJ...840...74A
Altcode: 2017arXiv170404136C
  We perform simulations for future Cherenkov Telescope Array (CTA)
  observations of RX J1713.7-3946, a young supernova remnant (SNR)
  and one of the brightest sources ever discovered in very high energy
  (VHE) gamma rays. Special attention is paid to exploring possible
  spatial (anti)correlations of gamma rays with emission at other
  wavelengths, in particular X-rays and CO/H I emission. We present a
  series of simulated images of RX J1713.7-3946 for CTA based on a set of
  observationally motivated models for the gamma-ray emission. In these
  models, VHE gamma rays produced by high-energy electrons are assumed
  to trace the nonthermal X-ray emission observed by XMM-Newton, whereas
  those originating from relativistic protons delineate the local gas
  distributions. The local atomic and molecular gas distributions are
  deduced by the NANTEN team from CO and H I observations. Our primary
  goal is to show how one can distinguish the emission mechanism(s) of the
  gamma rays (I.e., hadronic versus leptonic, or a mixture of the two)
  through information provided by their spatial distribution, spectra,
  and time variation. This work is the first attempt to quantitatively
  evaluate the capabilities of CTA to achieve various proposed scientific
  goals by observing this important cosmic particle accelerator.

Title: High-frequency Oscillations in Small Magnetic Elements Observed
    with Sunrise/SuFI
Authors: Jafarzadeh, S.; Solanki, S. K.; Stangalini, M.; Steiner,
   O.; Cameron, R. H.; Danilovic, S.
Bibcode: 2017ApJS..229...10J
Altcode: 2016arXiv161109302J
  We characterize waves in small magnetic elements and investigate
  their propagation in the lower solar atmosphere from observations at
  high spatial and temporal resolution. We use the wavelet transform to
  analyze oscillations of both horizontal displacement and intensity
  in magnetic bright points found in the 300 nm and the Ca II H 396.8
  nm passbands of the filter imager on board the Sunrise balloon-borne
  solar observatory. Phase differences between the oscillations at the
  two atmospheric layers corresponding to the two passbands reveal
  upward propagating waves at high frequencies (up to 30 mHz). Weak
  signatures of standing as well as downward propagating waves are also
  obtained. Both compressible and incompressible (kink) waves are found
  in the small-scale magnetic features. The two types of waves have
  different, though overlapping, period distributions. Two independent
  estimates give a height difference of approximately 450 ± 100 km
  between the two atmospheric layers sampled by the employed spectral
  bands. This value, together with the determined short travel times of
  the transverse and longitudinal waves provide us with phase speeds of 29
  ± 2 km s<SUP>-1</SUP> and 31 ± 2 km s<SUP>-1</SUP>, respectively. We
  speculate that these phase speeds may not reflect the true propagation
  speeds of the waves. Thus, effects such as the refraction of fast
  longitudinal waves may contribute to an overestimate of the phase speed.

Title: Kinematics of Magnetic Bright Features in the Solar Photosphere
Authors: Jafarzadeh, S.; Solanki, S. K.; Cameron, R. H.; Barthol, P.;
   Blanco Rodríguez, J.; del Toro Iniesta, J. C.; Gandorfer, A.; Gizon,
   L.; Hirzberger, J.; Knölker, M.; Martínez Pillet, V.; Orozco Suárez,
   D.; Riethmüller, T. L.; Schmidt, W.; van Noort, M.
Bibcode: 2017ApJS..229....8J
Altcode: 2016arXiv161007634J
  Convective flows are known as the prime means of transporting magnetic
  fields on the solar surface. Thus, small magnetic structures are good
  tracers of turbulent flows. We study the migration and dispersal
  of magnetic bright features (MBFs) in intergranular areas observed
  at high spatial resolution with Sunrise/IMaX. We describe the flux
  dispersal of individual MBFs as a diffusion process whose parameters are
  computed for various areas in the quiet-Sun and the vicinity of active
  regions from seeing-free data. We find that magnetic concentrations
  are best described as random walkers close to network areas (diffusion
  index, γ =1.0), travelers with constant speeds over a supergranule
  (γ =1.9{--}2.0), and decelerating movers in the vicinity of flux
  emergence and/or within active regions (γ =1.4{--}1.5). The three
  types of regions host MBFs with mean diffusion coefficients of 130
  km<SUP>2</SUP> s<SUP>-1</SUP>, 80-90 km<SUP>2</SUP> s<SUP>-1</SUP>,
  and 25-70 km<SUP>2</SUP> s<SUP>-1</SUP>, respectively. The MBFs in
  these three types of regions are found to display a distinct kinematic
  behavior at a confidence level in excess of 95%.

Title: An update of Leighton's solar dynamo model
Authors: Cameron, R. H.; Schüssler, M.
Bibcode: 2017A&A...599A..52C
Altcode: 2016arXiv161109111C
  In 1969, Leighton developed a quasi-1D mathematical model of the solar
  dynamo, building upon the phenomenological scenario of Babcock published
  in 1961. Here we present a modification and extension of Leighton's
  model. Using the axisymmetric component (longitudinal average) of
  the magnetic field, we consider the radial field component at the
  solar surface and the radially integrated toroidal magnetic flux in
  the convection zone, both as functions of latitude. No assumptions
  are made with regard to the radial location of the toroidal flux. The
  model includes the effects of (I) turbulent diffusion at the surface
  and in the convection zone; (II) poleward meridional flow at the
  surface and an equatorward return flow affecting the toroidal flux;
  (III) latitudinal differential rotation and the near-surface layer of
  radial rotational shear; (iv) downward convective pumping of magnetic
  flux in the shear layer; and (v) flux emergence in the form of tilted
  bipolar magnetic regions treated as a source term for the radial surface
  field. While the parameters relevant for the transport of the surface
  field are taken from observations, the model condenses the unknown
  properties of magnetic field and flow in the convection zone into a
  few free parameters (turbulent diffusivity, effective return flow,
  amplitude of the source term, and a parameter describing the effective
  radial shear). Comparison with the results of 2D flux transport
  dynamo codes shows that the model captures the essential features of
  these simulations. We make use of the computational efficiency of the
  model to carry out an extended parameter study. We cover an extended
  domain of the 4D parameter space and identify the parameter ranges
  that provide solar-like solutions. Dipole parity is always preferred
  and solutions with periods around 22 yr and a correct phase difference
  between flux emergence in low latitudes and the strength of the polar
  fields are found for a return flow speed around 2 m s<SUP>-1</SUP>,
  turbulent diffusivity below about 80 km<SUP>2</SUP>s<SUP>-1</SUP>,
  and dynamo excitation not too far above the threshold (linear growth
  rate less than 0.1 yr<SUP>-1</SUP>).

Title: Inflows towards active regions and the modulation of the
solar cycle: A parameter study
Authors: Martin-Belda, D.; Cameron, R. H.
Bibcode: 2017A&A...597A..21M
Altcode: 2016A&A...597A..21M; 2016arXiv160901199M
  <BR /> Aims: We aim to investigate how converging flows towards active
  regions affect the surface transport of magnetic flux, as well as
  their impact on the generation of the Sun's poloidal field. The inflows
  constitute a potential non-linear mechanism for the saturation of the
  global dynamo and may contribute to the modulation of the solar cycle in
  the Babcock-Leighton framework. <BR /> Methods: We build a surface flux
  transport code incorporating a parametrized model of the inflows and run
  simulations spanning several cycles. We carry out a parameter study to
  assess how the strength and extension of the inflows affect the build-up
  of the global dipole field. We also perform simulations with different
  levels of activity to investigate the potential role of the inflows in
  the saturation of the global dynamo. <BR /> Results: We find that the
  interaction of neighbouring active regions can lead to the occasional
  formation of single-polarity magnetic flux clumps that are inconsistent
  with observations. We propose the darkening caused by pores in areas
  of high magnetic field strength as a possible mechanism preventing
  this flux-clumping. We find that inflows decrease the amplitude of the
  axial dipole moment by 30%, relative to a no-inflows scenario. Stronger
  (weaker) inflows lead to larger (smaller) reductions of the axial dipole
  moment. The relative amplitude of the generated axial dipole is about
  9% larger after very weak cycles than after very strong cycles. This
  supports the idea that the inflows are a non-linear mechanism that
  is capable of saturating the global dynamo and contributing to the
  modulation of the solar cycle within the Babcock-Leighton framework.

Title: Babcock-Leighton Solar Dynamo: The Role of Downward Pumping
    and the Equatorward Propagation of Activity
Authors: Karak, Bidya Binay; Cameron, Robert
Bibcode: 2016ApJ...832...94K
Altcode: 2016arXiv160506224K
  The key elements of the Babcock-Leighton dynamos are the generation of
  poloidal field through decay and the dispersal of tilted bipolar active
  regions and the generation of toroidal field through the observed
  differential rotation. These models are traditionally known as flux
  transport dynamo models as the equatorward propagations of the butterfly
  wings in these models are produced due to an equatorward flow at the
  bottom of the convection zone. Here we investigate the role of downward
  magnetic pumping near the surface using a kinematic Babcock-Leighton
  model. We find that the pumping causes the poloidal field to become
  predominately radial in the near-surface shear layer, which allows
  the negative radial shear to effectively act on the radial field to
  produce a toroidal field. We observe a clear equatorward migration of
  the toroidal field at low latitudes as a consequence of the dynamo wave
  even when there is no meridional flow in the deep convection zone. Both
  the dynamo wave and the flux transport type solutions are thus able to
  reproduce some of the observed features of the solar cycle including
  the 11-year periodicity. The main difference between the two types of
  solutions is the strength of the Babcock-Leighton source required to
  produce the dynamo action. A second consequence of the magnetic pumping
  is that it suppresses the diffusion of fields through the surface,
  which helps to allow an 11-year cycle at (moderately) larger values
  of magnetic diffusivity than have previously been used.

Title: Comparing Time-Distance Results within a Coronal Hole to the
    Quiet Sun
Authors: Hess Webber, Shea A.; Pesnell, W. Dean; Duvall, Thomas, Jr.;
   Birch, Aaron; Cameron, Robert
Bibcode: 2016usc..confE...1H
Altcode:
  Time-distance helioseismology studies perturbations in solar
  wave modes. We use these techniques with SDO/HMI time-distance
  velocity-tracked dopplergram data to investigate differences between f
  -mode wave propagation within a coronal hole feature and without. We
  use symmetry arguments to enhance the signal-to-noise ratio of the
  cross-correlation results. We then look for phase and amplitude
  discrepancies between the coronal hole and quiet sun by comparing
  statistically significant differences between the regions.

Title: A solar-like magnetic cycle on the mature K-dwarf 61 Cygni A
    (HD 201091)
Authors: Boro Saikia, S.; Jeffers, S. V.; Morin, J.; Petit, P.;
   Folsom, C. P.; Marsden, S. C.; Donati, J. -F.; Cameron, R.; Hall,
   J. C.; Perdelwitz, V.; Reiners, A.; Vidotto, A. A.
Bibcode: 2016A&A...594A..29B
Altcode: 2016arXiv160601032B
  Context. The long-term monitoring of magnetic cycles in cool stars is a
  key diagnostic in understanding how dynamo generation and amplification
  of magnetic fields occur in stars similar in structure to the Sun. <BR
  /> Aims: We investigated the temporal evolution of a possible magnetic
  cycle of 61 Cyg A. The magnetic cycle is determined from 61 Cyg A's
  large-scale field over its activity cycle using spectropolarimetric
  observations and compared to the solar large-scale magnetic field. <BR
  /> Methods: We used the tomographic technique of Zeeman Doppler imaging
  (ZDI) to reconstruct the large-scale magnetic geometry of 61 Cyg A
  over multiple observational epochs spread over a time span of nine
  years. We investigated the time evolution of the different components
  of the large-scale field and compared it with the evolution of the
  star's chromospheric activity by measuring the flux in three different
  chromospheric indicators: Ca II H&amp;K, Hα and Ca II infrared triplet
  lines. We also compared our results with the star's coronal activity
  using XMM-Newton observations. <BR /> Results: The large-scale magnetic
  geometry of 61 Cyg A exhibits polarity reversals in both poloidal and
  toroidal field components, in phase with its chromospheric activity
  cycle. We also detect weak solar-like differential rotation with
  a shear level similar to that of the Sun. During our observational
  time span of nine years, 61 Cyg A exhibits solar- like variations in
  its large-scale field geometry as it evolves from minimum activity
  to maximum activity and vice versa. During its activity minimum in
  epoch 2007.59, ZDI reconstructs a simple dipolar geometry which becomes
  more complex when it approaches activity maximum in epoch 2010.55. The
  radial field flips polarity and reverts back to a simple geometry in
  epoch 2013.61. The field is strongly dipolar and the evolution of the
  dipole component of the field is reminiscent of solar behaviour. The
  polarity reversal of the large-scale field indicates a magnetic cycle
  that is in phase with the chromospheric and coronal cycle.

Title: Observed and simulated power spectra of kinetic and magnetic
    energy retrieved with 2D inversions
Authors: Danilovic, S.; Rempel, M.; van Noort, M.; Cameron, R.
Bibcode: 2016A&A...594A.103D
Altcode: 2016arXiv160706242D
  Context. Information on the origin of internetwork magnetic field is
  hidden at the smallest spatial scales. <BR /> Aims: We try to retrieve
  the power spectra with certainty to the highest spatial frequencies
  allowed by current instrumentation. <BR /> Methods: To accomplish this,
  we use a 2D inversion code that is able to recover information up to
  the instrumental diffraction limit. <BR /> Results: The retrieved power
  spectra have shallow slopes that extend further down to much smaller
  scales than has been found before. They do not seem to show any power
  law. The observed slopes at subgranular scales agree with those obtained
  from recent local dynamo simulations. Small differences are found for
  the vertical component of kinetic energy that suggest that observations
  suffer from an instrumental effect that is not taken into account. <BR
  /> Conclusions: Local dynamo simulations quantitatively reproduce the
  observed magnetic energy power spectra on the scales of granulation
  down to the resolution limit of Hinode/SP, within the error bars
  inflicted by the method used and the instrumental effects replicated.

Title: Contributions of the Cherenkov Telescope Array (CTA) to
    the 6th International Symposium on High-Energy Gamma-Ray Astronomy
    (Gamma 2016)
Authors: CTA Consortium, The; :; Abchiche, A.; Abeysekara, U.; Abril,
   Ó.; Acero, F.; Acharya, B. S.; Adams, C.; Agnetta, G.; Aharonian,
   F.; Akhperjanian, A.; Albert, A.; Alcubierre, M.; Alfaro, J.; Alfaro,
   R.; Allafort, A. J.; Aloisio, R.; Amans, J. -P.; Amato, E.; Ambrogi,
   L.; Ambrosi, G.; Ambrosio, M.; Anderson, J.; Anduze, M.; Angüner,
   E. O.; Antolini, E.; Antonelli, L. A.; Antonucci, M.; Antonuccio,
   V.; Antoranz, P.; Aramo, C.; Aravantinos, A.; Araya, M.; Arcaro, C.;
   Arezki, B.; Argan, A.; Armstrong, T.; Arqueros, F.; Arrabito, L.;
   Arrieta, M.; Asano, K.; Ashley, M.; Aubert, P.; Singh, C. B.; Babic,
   A.; Backes, M.; Bais, A.; Bajtlik, S.; Balazs, C.; Balbo, M.; Balis,
   D.; Balkowski, C.; Ballester, O.; Ballet, J.; Balzer, A.; Bamba,
   A.; Bandiera, R.; Barber, A.; Barbier, C.; Barcelo, M.; Barkov,
   M.; Barnacka, A.; Barres de Almeida, U.; Barrio, J. A.; Basso, S.;
   Bastieri, D.; Bauer, C.; Becciani, U.; Becherini, Y.; Becker Tjus,
   J.; Beckmann, V.; Bednarek, W.; Benbow, W.; Benedico Ventura, D.;
   Berdugo, J.; Berge, D.; Bernardini, E.; Bernardini, M. G.; Bernhard,
   S.; Bernlöhr, K.; Bertucci, B.; Besel, M. -A.; Beshley, V.; Bhatt,
   N.; Bhattacharjee, P.; Bhattacharyya, W.; Bhattachryya, S.; Biasuzzi,
   B.; Bicknell, G.; Bigongiari, C.; Biland, A.; Bilinsky, A.; Bilnik,
   W.; Biondo, B.; Bird, R.; Bird, T.; Bissaldi, E.; Bitossi, M.;
   Blanch, O.; Blasi, P.; Blazek, J.; Bockermann, C.; Boehm, C.; Bogacz,
   L.; Bogdan, M.; Bohacova, M.; Boisson, C.; Boix, J.; Bolmont, J.;
   Bonanno, G.; Bonardi, A.; Bonavolontà, C.; Bonifacio, P.; Bonnarel,
   F.; Bonnoli, G.; Borkowski, J.; Bose, R.; Bosnjak, Z.; Böttcher, M.;
   Bousquet, J. -J.; Boutonnet, C.; Bouyjou, F.; Bowman, L.; Braiding,
   C.; Brantseg, T.; Brau-Nogué, S.; Bregeon, J.; Briggs, M.; Brigida,
   M.; Bringmann, T.; Brisken, W.; Bristow, D.; Britto, R.; Brocato, E.;
   Bron, S.; Brook, P.; Brooks, W.; Brown, A. M.; Brügge, K.; Brun, F.;
   Brun, P.; Brun, P.; Brunetti, G.; Brunetti, L.; Bruno, P.; Buanes,
   T.; Bucciantini, N.; Buchholtz, G.; Buckley, J.; Bugaev, V.; Bühler,
   R.; Bulgarelli, A.; Bulik, T.; Burton, M.; Burtovoi, A.; Busetto,
   G.; Buson, S.; Buss, J.; Byrum, K.; Cadoux, F.; Calvo Tovar, J.;
   Cameron, R.; Canelli, F.; Canestrari, R.; Capalbi, M.; Capasso, M.;
   Capobianco, G.; Caproni, A.; Caraveo, P.; Cardenzana, J.; Cardillo,
   M.; Carius, S.; Carlile, C.; Carosi, A.; Carosi, R.; Carquín, E.;
   Carr, J.; Carroll, M.; Carter, J.; Carton, P. -H.; Casandjian, J. -M.;
   Casanova, S.; Casanova, S.; Cascone, E.; Casiraghi, M.; Castellina,
   A.; Castroviejo Mora, J.; Catalani, F.; Catalano, O.; Catalanotti,
   S.; Cauz, D.; Cavazzani, S.; Cerchiara, P.; Chabanne, E.; Chadwick,
   P.; Chaleil, T.; Champion, C.; Chatterjee, A.; Chaty, S.; Chaves, R.;
   Chen, A.; Chen, X.; Chen, X.; Cheng, K.; Chernyakova, M.; Chiappetti,
   L.; Chikawa, M.; Chinn, D.; Chitnis, V. R.; Cho, N.; Christov, A.;
   Chudoba, J.; Cieślar, M.; Ciocci, M. A.; Clay, R.; Colafrancesco,
   S.; Colin, P.; Colley, J. -M.; Colombo, E.; Colome, J.; Colonges, S.;
   Conforti, V.; Connaughton, V.; Connell, S.; Conrad, J.; Contreras,
   J. L.; Coppi, P.; Corbel, S.; Coridian, J.; Cornat, R.; Corona,
   P.; Corti, D.; Cortina, J.; Cossio, L.; Costa, A.; Costantini, H.;
   Cotter, G.; Courty, B.; Covino, S.; Covone, G.; Crimi, G.; Criswell,
   S. J.; Crocker, R.; Croston, J.; Cuadra, J.; Cumani, P.; Cusumano,
   G.; Da Vela, P.; Dale, Ø.; D'Ammando, F.; Dang, D.; Dang, V. T.;
   Dangeon, L.; Daniel, M.; Davids, I.; Davids, I.; Dawson, B.; Dazzi,
   F.; de Aguiar Costa, B.; De Angelis, A.; de Araujo Cardoso, R. F.;
   De Caprio, V.; de Cássia dos Anjos, R.; De Cesare, G.; De Franco,
   A.; De Frondat, F.; de Gouveia Dal Pino, E. M.; de la Calle, I.;
   De Lisio, C.; de los Reyes Lopez, R.; De Lotto, B.; De Luca, A.; de
   Mello Neto, J. R. T.; de Naurois, M.; de Oña Wilhelmi, E.; De Palma,
   F.; De Persio, F.; de Souza, V.; Decock, G.; Decock, J.; Deil, C.;
   Del Santo, M.; Delagnes, E.; Deleglise, G.; Delgado, C.; Delgado, J.;
   della Volpe, D.; Deloye, P.; Detournay, M.; Dettlaff, A.; Devin, J.;
   Di Girolamo, T.; Di Giulio, C.; Di Paola, A.; Di Pierro, F.; Diaz,
   M. A.; Díaz, C.; Dib, C.; Dick, J.; Dickinson, H.; Diebold, S.;
   Digel, S.; Dipold, J.; Disset, G.; Distefano, A.; Djannati-Ataï, A.;
   Doert, M.; Dohmke, M.; Domínguez, A.; Dominik, N.; Dominique, J. -L.;
   Dominis Prester, D.; Donat, A.; Donnarumma, I.; Dorner, D.; Doro,
   M.; Dournaux, J. -L.; Downes, T.; Doyle, K.; Drake, G.; Drappeau,
   S.; Drass, H.; Dravins, D.; Drury, L.; Dubus, G.; Ducci, L.; Dumas,
   D.; Dundas Morå, K.; Durand, D.; D'Urso, D.; Dwarkadas, V.; Dyks,
   J.; Dyrda, M.; Ebr, J.; Edy, E.; Egberts, K.; Eger, P.; Egorov, A.;
   Einecke, S.; Eisch, J.; Eisenkolb, F.; Eleftheriadis, C.; Elsaesser,
   D.; Elsässer, D.; Emmanoulopoulos, D.; Engelbrecht, C.; Engelhaupt,
   D.; Ernenwein, J. -P.; Escarate, P.; Eschbach, S.; Espinoza, C.;
   Evans, P.; Fairbairn, M.; Falceta-Goncalves, D.; Falcone, A.; Fallah
   Ramazani, V.; Fantinel, D.; Farakos, K.; Farnier, C.; Farrell, E.;
   Fasola, G.; Favre, Y.; Fede, E.; Fedora, R.; Fedorova, E.; Fegan, S.;
   Ferenc, D.; Fernandez-Alonso, M.; Fernández-Barral, A.; Ferrand, G.;
   Ferreira, O.; Fesquet, M.; Fetfatzis, P.; Fiandrini, E.; Fiasson, A.;
   Filipčič, A.; Filipovic, M.; Fink, D.; Finley, C.; Finley, J. P.;
   Finoguenov, A.; Fioretti, V.; Fiorini, M.; Fleischhack, H.; Flores,
   H.; Florin, D.; Föhr, C.; Fokitis, E.; Fonseca, M. V.; Font, L.;
   Fontaine, G.; Fontes, B.; Fornasa, M.; Fornasa, M.; Förster, A.;
   Fortin, P.; Fortson, L.; Fouque, N.; Franckowiak, A.; Franckowiak,
   A.; Franco, F. J.; Freire Mota Albuquerque, I.; Freixas Coromina,
   L.; Fresnillo, L.; Fruck, C.; Fuessling, M.; Fugazza, D.; Fujita, Y.;
   Fukami, S.; Fukazawa, Y.; Fukuda, T.; Fukui, Y.; Funk, S.; Furniss, A.;
   Gäbele, W.; Gabici, S.; Gadola, A.; Galindo, D.; Gall, D. D.; Gallant,
   Y.; Galloway, D.; Gallozzi, S.; Galvez, J. A.; Gao, S.; Garcia, A.;
   Garcia, B.; García Gil, R.; Garcia López, R.; Garczarczyk, M.;
   Gardiol, D.; Gargano, C.; Gargano, F.; Garozzo, S.; Garrecht, F.;
   Garrido, L.; Garrido-Ruiz, M.; Gascon, D.; Gaskins, J.; Gaudemard,
   J.; Gaug, M.; Gaweda, J.; Gebhardt, B.; Gebyehu, M.; Geffroy, N.;
   Genolini, B.; Gerard, L.; Ghalumyan, A.; Ghedina, A.; Ghislain, P.;
   Giammaria, P.; Giannakaki, E.; Gianotti, F.; Giarrusso, S.; Giavitto,
   G.; Giebels, B.; Gieras, T.; Giglietto, N.; Gika, V.; Gimenes, R.;
   Giomi, M.; Giommi, P.; Giordano, F.; Giovannini, G.; Girardot, P.;
   Giro, E.; Giroletti, M.; Gironnet, J.; Giuliani, A.; Glicenstein,
   J. -F.; Gnatyk, R.; Godinovic, N.; Goldoni, P.; Gomez, G.; Gonzalez,
   M. M.; González, A.; Gora, D.; Gothe, K. S.; Gotz, D.; Goullon, J.;
   Grabarczyk, T.; Graciani, R.; Graham, J.; Grandi, P.; Granot, J.;
   Grasseau, G.; Gredig, R.; Green, A. J.; Green, A. M.; Greenshaw, T.;
   Grenier, I.; Griffiths, S.; Grillo, A.; Grondin, M. -H.; Grube, J.;
   Grudzinska, M.; Grygorczuk, J.; Guarino, V.; Guberman, D.; Gunji, S.;
   Gyuk, G.; Hadasch, D.; Hagedorn, A.; Hagge, L.; Hahn, J.; Hakobyan,
   H.; Hara, S.; Hardcastle, M. J.; Hassan, T.; Hatanaka, K.; Haubold,
   T.; Haupt, A.; Hayakawa, T.; Hayashida, M.; Heller, M.; Heller,
   R.; Helo, J. C.; Henault, F.; Henri, G.; Hermann, G.; Hermel, R.;
   Herrera Llorente, J.; Herrera Llorente, J.; Herrero, A.; Hervet,
   O.; Hidaka, N.; Hinton, J.; Hirai, W.; Hirotani, K.; Hnatyk, B.;
   Hoang, J.; Hoffmann, D.; Hofmann, W.; Holch, T.; Holder, J.; Hooper,
   S.; Horan, D.; Hörandel, J.; Hörbe, M.; Horns, D.; Horvath, P.;
   Hose, J.; Houles, J.; Hovatta, T.; Hrabovsky, M.; Hrupec, D.; Huet,
   J. -M.; Huetten, M.; Hughes, G.; Hui, D.; Humensky, T. B.; Hussein,
   M.; Iacovacci, M.; Ibarra, A.; Ikeno, Y.; Illa, J. M.; Impiombato,
   D.; Inada, T.; Incorvaia, S.; Infante, L.; Inome, Y.; Inoue, S.;
   Inoue, T.; Inoue, Y.; Iocco, F.; Ioka, K.; Iori, M.; Ishio, K.;
   Ishio, K.; Israel, G. L.; Iwamura, Y.; Jablonski, C.; Jacholkowska,
   A.; Jacquemier, J.; Jamrozy, M.; Janecek, P.; Janiak, M.; Jankowsky,
   D.; Jankowsky, F.; Jean, P.; Jegouzo, I.; Jenke, P.; Jimenez, J. J.;
   Jingo, M.; Jingo, M.; Jocou, L.; Jogler, T.; Johnson, C. A.; Jones,
   M.; Josselin, M.; Journet, L.; Jung, I.; Kaaret, P.; Kagaya, M.;
   Kakuwa, J.; Kalekin, O.; Kalkuhl, C.; Kamon, H.; Kankanyan, R.;
   Karastergiou, A.; Kärcher, K.; Karczewski, M.; Karkar, S.; Karn, P.;
   Kasperek, J.; Katagiri, H.; Kataoka, J.; Katarzyński, K.; Kato, S.;
   Katz, U.; Kawanaka, N.; Kaye, L.; Kazanas, D.; Kelley-Hoskins, N.;
   Kersten, J.; Khélifi, B.; Kieda, D. B.; Kihm, T.; Kimeswenger, S.;
   Kisaka, S.; Kishida, S.; Kissmann, R.; Klepser, S.; Kluźniak, W.;
   Knapen, J.; Knapp, J.; Knödlseder, J.; Koch, B.; Köck, F.; Kocot,
   J.; Kohri, K.; Kokkotas, K.; Kokkotas, K.; Kolitzus, D.; Komin, N.;
   Kominis, I.; Kong, A.; Konno, Y.; Kosack, K.; Koss, G.; Kossatz, M.;
   Kowal, G.; Koyama, S.; Kozioł, J.; Kraus, M.; Krause, J.; Krause, M.;
   Krawzcynski, H.; Krennrich, F.; Kretzschmann, A.; Kruger, P.; Kubo, H.;
   Kudryavtsev, V.; Kukec Mezek, G.; Kuklis, M.; Kuroda, H.; Kushida, J.;
   La Barbera, A.; La Palombara, N.; La Parola, V.; La Rosa, G.; Laffon,
   H.; Lahmann, R.; Lakicevic, M.; Lalik, K.; Lamanna, G.; Landriu,
   D.; Landt, H.; Lang, R. G.; Lapington, J.; Laporte, P.; Le Fèvre,
   J. -P.; Le Flour, T.; Le Sidaner, P.; Lee, S. -H.; Lee, W. H.; Lees,
   J. -P.; Lefaucheur, J.; Leffhalm, K.; Leich, H.; Leigui de Oliveira,
   M. A.; Lelas, D.; Lemière, A.; Lemoine-Goumard, M.; Lenain, J. -P.;
   Leonard, R.; Leoni, R.; Lessio, L.; Leto, G.; Leveque, A.; Lieunard,
   B.; Limon, M.; Lindemann, R.; Lindfors, E.; Linhoff, L.; Liolios,
   A.; Lipniacka, A.; Lockart, H.; Lohse, T.; Łokas, E.; Lombardi, S.;
   Longo, F.; Lopatin, A.; Lopez, M.; Loreggia, D.; Louge, T.; Louis,
   F.; Louys, M.; Lucarelli, F.; Lucchesi, D.; Lüdecke, H.; Luigi, T.;
   Luque-Escamilla, P. L.; Lyard, E.; Maccarone, M. C.; Maccarone, T.;
   Maccarone, T. J.; Mach, E.; Madejski, G. M.; Madonna, A.; Magniette,
   F.; Magniez, A.; Mahabir, M.; Maier, G.; Majumdar, P.; Majumdar, P.;
   Makariev, M.; Malaguti, G.; Malaspina, G.; Mallot, A. K.; Malouf,
   A.; Maltezos, S.; Malyshev, D.; Mancilla, A.; Mandat, D.; Maneva, G.;
   Manganaro, M.; Mangano, S.; Manigot, P.; Mankushiyil, N.; Mannheim, K.;
   Maragos, N.; Marano, D.; Marchegiani, P.; Marcomini, J. A.; Marcowith,
   A.; Mariotti, M.; Marisaldi, M.; Markoff, S.; Martens, C.; Martí,
   J.; Martin, J. -M.; Martin, L.; Martin, P.; Martínez, G.; Martínez,
   M.; Martínez, O.; Martynyuk-Lototskyy, K.; Marx, R.; Masetti, N.;
   Massimino, P.; Mastichiadis, A.; Mastroianni, S.; Mastropietro, M.;
   Masuda, S.; Matsumoto, H.; Matsuoka, S.; Matthews, N.; Mattiazzo, S.;
   Maurin, G.; Maxted, N.; Maxted, N.; Maya, J.; Mayer, M.; Mazin, D.;
   Mazziotta, M. N.; Mc Comb, L.; McCubbin, N.; McHardy, I.; Medina,
   C.; Mehrez, F.; Melioli, C.; Melkumyan, D.; Melse, T.; Mereghetti,
   S.; Merk, M.; Mertsch, P.; Meunier, J. -L.; Meures, T.; Meyer, M.;
   Meyrelles, J. L., jr; Miccichè, A.; Michael, T.; Michałowski, J.;
   Mientjes, P.; Mievre, I.; Mihailidis, A.; Miller, J.; Mineo, T.;
   Minuti, M.; Mirabal, N.; Mirabel, F.; Miranda, J. M.; Mirzoyan, R.;
   Mitchell, A.; Mizuno, T.; Moderski, R.; Mognet, I.; Mohammed, M.;
   Moharana, R.; Mohrmann, L.; Molinari, E.; Molyneux, P.; Monmarthe,
   E.; Monnier, G.; Montaruli, T.; Monte, C.; Monteiro, I.; Mooney, D.;
   Moore, P.; Moralejo, A.; Morello, C.; Moretti, E.; Mori, K.; Morris,
   P.; Morselli, A.; Moscato, F.; Motohashi, D.; Mottez, F.; Moudden,
   Y.; Moulin, E.; Mueller, S.; Mukherjee, R.; Munar, P.; Munari, M.;
   Mundell, C.; Mundet, J.; Muraishi, H.; Murase, K.; Muronga, A.; Murphy,
   A.; Nagar, N.; Nagataki, S.; Nagayoshi, T.; Nagesh, B. K.; Naito,
   T.; Nakajima, D.; Nakajima, D.; Nakamori, T.; Nakayama, K.; Nanni,
   J.; Naumann, D.; Nayman, P.; Nellen, L.; Nemmen, R.; Neronov, A.;
   Neyroud, N.; Nguyen, T.; Nguyen, T. T.; Nguyen Trung, T.; Nicastro, L.;
   Nicolau-Kukliński, J.; Niederwanger, F.; Niedźwiecki, A.; Niemiec,
   J.; Nieto, D.; Nievas-Rosillo, M.; Nikolaidis, A.; Nikołajuk, M.;
   Nishijima, K.; Nishikawa, K. -I.; Nishiyama, G.; Noda, K.; Noda,
   K.; Nogues, L.; Nolan, S.; Northrop, R.; Nosek, D.; Nöthe, M.;
   Novosyadlyj, B.; Nozka, L.; Nunio, F.; Oakes, L.; O'Brien, P.; Ocampo,
   C.; Occhipinti, G.; Ochoa, J. P.; OFaolain de Bhroithe, A.; Oger, R.;
   Ohira, Y.; Ohishi, M.; Ohm, S.; Ohoka, H.; Okazaki, N.; Okumura, A.;
   Olive, J. -F.; Olszowski, D.; Ong, R. A.; Ono, S.; Orienti, M.; Orito,
   R.; Orlati, A.; Osborne, J.; Ostrowski, M.; Ottaway, D.; Otte, N.;
   Öttl, S.; Ovcharov, E.; Oya, I.; Ozieblo, A.; Padovani, M.; Pagano,
   I.; Paiano, S.; Paizis, A.; Palacio, J.; Palatka, M.; Pallotta, J.;
   Panagiotidis, K.; Panazol, J. -L.; Paneque, D.; Panter, M.; Panzera,
   M. R.; Paoletti, R.; Paolillo, M.; Papayannis, A.; Papyan, G.; Paravac,
   A.; Paredes, J. M.; Pareschi, G.; Park, N.; Parsons, D.; Paśko, P.;
   Pavy, S.; Pech, M.; Peck, A.; Pedaletti, G.; Pe'er, A.; Peet, S.;
   Pelat, D.; Pepato, A.; Perez, M. d. C.; Perri, L.; Perri, M.; Persic,
   M.; Persic, M.; Petrashyk, A.; Petrucci, P. -O.; Petruk, O.; Peyaud,
   B.; Pfeifer, M.; Pfeiffer, G.; Piano, G.; Pieloth, D.; Pierre, E.;
   Pinto de Pinho, F.; García, C. Pio; Piret, Y.; Pisarski, A.; Pita,
   S.; Platos, Ł.; Platzer, R.; Podkladkin, S.; Pogosyan, L.; Pohl,
   M.; Poinsignon, P.; Pollo, A.; Porcelli, A.; Porthault, J.; Potter,
   W.; Poulios, S.; Poutanen, J.; Prandini, E.; Prandini, E.; Prast, J.;
   Pressard, K.; Principe, G.; Profeti, F.; Prokhorov, D.; Prokoph, H.;
   Prouza, M.; Pruchniewicz, R.; Pruteanu, G.; Pueschel, E.; Pühlhofer,
   G.; Puljak, I.; Punch, M.; Pürckhauer, S.; Pyzioł, R.; Queiroz,
   F.; Quel, E. J.; Quinn, J.; Quirrenbach, A.; Rafighi, I.; Rainò, S.;
   Rajda, P. J.; Rameez, M.; Rando, R.; Rannot, R. C.; Rataj, M.; Ravel,
   T.; Razzaque, S.; Reardon, P.; Reichardt, I.; Reimann, O.; Reimer,
   A.; Reimer, O.; Reisenegger, A.; Renaud, M.; Renner, S.; Reposeur,
   T.; Reville, B.; Rezaeian, A.; Rhode, W.; Ribeiro, D.; Ribeiro Prado,
   R.; Ribó, M.; Richards, G.; Richer, M. G.; Richtler, T.; Rico, J.;
   Ridky, J.; Rieger, F.; Riquelme, M.; Ristori, P. R.; Rivoire, S.; Rizi,
   V.; Roache, E.; Rodriguez, J.; Rodriguez Fernandez, G.; Rodríguez
   Vázquez, J. J.; Rojas, G.; Romano, P.; Romeo, G.; Roncadelli, M.;
   Rosado, J.; Rose, J.; Rosen, S.; Rosier Lees, S.; Ross, D.; Rouaix,
   G.; Rousselle, J.; Rovero, A. C.; Rowell, G.; Roy, F.; Royer, S.;
   Rubini, A.; Rudak, B.; Rugliancich, A.; Rujopakarn, W.; Rulten,
   C.; Rupiński, M.; Russo, F.; Russo, F.; Rutkowski, K.; Saavedra,
   O.; Sabatini, S.; Sacco, B.; Sadeh, I.; Saemann, E. O.; Safi-Harb,
   S.; Saggion, A.; Sahakian, V.; Saito, T.; Sakaki, N.; Sakurai, S.;
   Salamon, A.; Salega, M.; Salek, D.; Salesa Greus, F.; Salgado, J.;
   Salina, G.; Salinas, L.; Salini, A.; Sanchez, D.; Sanchez-Conde, M.;
   Sandaker, H.; Sandoval, A.; Sangiorgi, P.; Sanguillon, M.; Sano, H.;
   Santander, M.; Santangelo, A.; Santos, E. M.; Santos-Lima, R.; Sanuy,
   A.; Sapozhnikov, L.; Sarkar, S.; Satalecka, K.; Satalecka, K.; Sato,
   Y.; Savalle, R.; Sawada, M.; Sayède, F.; Schanne, S.; Schanz, T.;
   Schioppa, E. J.; Schlenstedt, S.; Schmid, J.; Schmidt, T.; Schmoll,
   J.; Schneider, M.; Schoorlemmer, H.; Schovanek, P.; Schubert, A.;
   Schullian, E. -M.; Schultze, J.; Schulz, A.; Schulz, S.; Schure, K.;
   Schussler, F.; Schwab, T.; Schwanke, U.; Schwarz, J.; Schweizer, T.;
   Schwemmer, S.; Schwendicke, U.; Schwerdt, C.; Sciacca, E.; Scuderi,
   S.; Segreto, A.; Seiradakis, J. -H.; Sembroski, G. H.; Semikoz, D.;
   Sergijenko, O.; Serre, N.; Servillat, M.; Seweryn, K.; Shafi, N.;
   Shalchi, A.; Sharma, M.; Shayduk, M.; Shellard, R. C.; Shibata, T.;
   Shigenaka, A.; Shilon, I.; Shum, E.; Sidoli, L.; Sidz, M.; Sieiro, J.;
   Siejkowski, H.; Silk, J.; Sillanpää, A.; Simone, D.; Simpson, H.;
   Singh, B. B.; Sinha, A.; Sironi, G.; Sitarek, J.; Sizun, P.; Sliusar,
   V.; Sliusar, V.; Smith, A.; Sobczyńska, D.; Sol, H.; Sottile, G.;
   Sowiński, M.; Spanier, F.; Spengler, G.; Spiga, R.; Stadler, R.;
   Stahl, O.; Stamerra, A.; Stanič, S.; Starling, R.; Staszak, D.;
   Stawarz, Ł.; Steenkamp, R.; Stefanik, S.; Stegmann, C.; Steiner, S.;
   Stella, C.; Stephan, M.; Stergioulas, N.; Sternberger, R.; Sterzel, M.;
   Stevenson, B.; Stinzing, F.; Stodulska, M.; Stodulski, M.; Stolarczyk,
   T.; Stratta, G.; Straumann, U.; Stringhetti, L.; Strzys, M.; Stuik,
   R.; Sulanke, K. -H.; Suomijärvi, T.; Supanitsky, A. D.; Suric, T.;
   Sushch, I.; Sutcliffe, P.; Sykes, J.; Szanecki, M.; Szepieniec, T.;
   Szwarnog, P.; Tacchini, A.; Tachihara, K.; Tagliaferri, G.; Tajima,
   H.; Takahashi, H.; Takahashi, K.; Takahashi, M.; Takalo, L.; Takami,
   S.; Takata, J.; Takeda, J.; Talbot, G.; Tam, T.; Tanaka, M.; Tanaka,
   S.; Tanaka, T.; Tanaka, Y.; Tanci, C.; Tanigawa, S.; Tavani, M.;
   Tavecchio, F.; Tavernet, J. -P.; Tayabaly, K.; Taylor, A.; Tejedor,
   L. A.; Telezhinsky, I.; Temme, F.; Temnikov, P.; Tenzer, C.; Terada,
   Y.; Terrazas, J. C.; Terrier, R.; Terront, D.; Terzic, T.; Tescaro,
   D.; Teshima, M.; Teshima, M.; Testa, V.; Tezier, D.; Thayer, J.;
   Thornhill, J.; Thoudam, S.; Thuermann, D.; Tibaldo, L.; Tiengo,
   A.; Timpanaro, M. C.; Tiziani, D.; Tluczykont, M.; Todero Peixoto,
   C. J.; Tokanai, F.; Tokarz, M.; Toma, K.; Tomastik, J.; Tomono, Y.;
   Tonachini, A.; Tonev, D.; Torii, K.; Tornikoski, M.; Torres, D. F.;
   Torres, M.; Torresi, E.; Toso, G.; Tosti, G.; Totani, T.; Tothill, N.;
   Toussenel, F.; Tovmassian, G.; Toyama, T.; Travnicek, P.; Trichard,
   C.; Trifoglio, M.; Troyano Pujadas, I.; Trzeciak, M.; Tsinganos, K.;
   Tsujimoto, S.; Tsuru, T.; Uchiyama, Y.; Umana, G.; Umetsu, Y.; Upadhya,
   S. S.; Uslenghi, M.; Vagelli, V.; Vagnetti, F.; Valdes-Galicia, J.;
   Valentino, M.; Vallania, P.; Valore, L.; van Driel, W.; van Eldik,
   C.; van Soelen, B.; Vandenbroucke, J.; Vanderwalt, J.; Vasileiadis,
   G.; Vassiliev, V.; Vázquez, J. R.; Vázquez Acosta, M. L.; Vecchi,
   M.; Vega, A.; Vegas, I.; Veitch, P.; Venault, P.; Venema, L.; Venter,
   C.; Vercellone, S.; Vergani, S.; Verma, K.; Verzi, V.; Vettolani,
   G. P.; Veyssiere, C.; Viana, A.; Viaux, N.; Vicha, J.; Vigorito,
   C.; Vincent, P.; Vincent, S.; Vink, J.; Vittorini, V.; Vlahakis, N.;
   Vlahos, L.; Voelk, H.; Voisin, V.; Vollhardt, A.; Volpicelli, A.; von
   Brand, H.; Vorobiov, S.; Vovk, I.; Vrastil, M.; Vu, L. V.; Vuillaume,
   T.; Wagner, R.; Wagner, R.; Wagner, S. J.; Wakely, S. P.; Walstra, T.;
   Walter, R.; Walther, T.; Ward, J. E.; Ward, M.; Warda, K.; Warren,
   D.; Wassberg, S.; Watson, J. J.; Wawer, P.; Wawrzaszek, R.; Webb,
   N.; Wegner, P.; Weiner, O.; Weinstein, A.; Wells, R.; Werner, F.;
   Wetteskind, H.; White, M.; White, R.; Więcek, M.; Wierzcholska, A.;
   Wiesand, S.; Wijers, R.; Wilcox, P.; Wild, N.; Wilhelm, A.; Wilkinson,
   M.; Will, M.; Will, M.; Williams, D. A.; Williams, J. T.; Willingale,
   R.; Wilson, N.; Winde, M.; Winiarski, K.; Winkler, H.; Winter, M.;
   Wischnewski, R.; Witt, E.; Wojcik, P.; Wolf, D.; Wood, M.; Wörnlein,
   A.; Wu, E.; Wu, T.; Yadav, K. K.; Yamamoto, H.; Yamamoto, T.; Yamane,
   N.; Yamazaki, R.; Yanagita, S.; Yang, L.; Yelos, D.; Yoshida, A.;
   Yoshida, M.; Yoshida, T.; Yoshiike, S.; Yoshikoshi, T.; Yu, P.;
   Zabalza, V.; Zaborov, D.; Zacharias, M.; Zaharijas, G.; Zajczyk,
   A.; Zampieri, L.; Zandanel, F.; Zanmar Sanchez, R.; Zaric, D.;
   Zavrtanik, D.; Zavrtanik, M.; Zdziarski, A.; Zech, A.; Zechlin, H.;
   Zhao, A.; Zhdanov, V.; Ziegler, A.; Ziemann, J.; Ziętara, K.; Zink,
   A.; Ziółkowski, J.; Zitelli, V.; Zoli, A.; Zorn, J.; Żychowski, P.
Bibcode: 2016arXiv161005151C
Altcode:
  List of contributions from the Cherenkov Telescope Array (CTA)
  Consortium presented at the 6th International Symposium on High-Energy
  Gamma-Ray Astronomy (Gamma 2016), July 11-15, 2016, in Heidelberg,
  Germany.

Title: MESA meets MURaM. Surface effects in main-sequence solar-like
    oscillators computed using three-dimensional radiation hydrodynamics
    simulations
Authors: Ball, W. H.; Beeck, B.; Cameron, R. H.; Gizon, L.
Bibcode: 2016A&A...592A.159B
Altcode: 2016arXiv160602713B
  Context. Space-based observations of solar-like oscillators have
  identified large numbers of stars in which many individual mode
  frequencies can be precisely measured. However, current stellar models
  predict oscillation frequencies that are systematically affected by
  simplified modelling of the near-surface layers. <BR /> Aims: We use
  three-dimensional radiation hydrodynamics simulations to better model
  the near-surface equilibrium structure of dwarfs with spectral types F3,
  G2, K0 and K5, and examine the differences between oscillation mode
  frequencies computed in stellar models with and without the improved
  near-surface equilibrium structure. <BR /> Methods: We precisely match
  stellar models to the simulations' gravities and effective temperatures
  at the surface, and to the temporally- and horizontally-averaged
  densities and pressures at their deepest points. We then replace
  the near-surface structure with that of the averaged simulation and
  compute the change in the oscillation mode frequencies. We also fit
  the differences using several parametric models currently available
  in the literature. <BR /> Results: The surface effect in the stars of
  solar-type and later is qualitatively similar and changes steadily
  with decreasing effective temperature. In particular, the point of
  greatest frequency difference decreases slightly as a fraction of
  the acoustic cut-off frequency and the overall scale of the surface
  effect decreases. The surface effect in the hot, F3-type star follows
  the same trend in scale (I.e. it is larger in magnitude) but shows
  a different overall variation with mode frequency. We find that a
  two-term fit using the cube and inverse of the frequency divided by
  the mode inertia is best able to reproduce the surface terms across
  all four spectral types, although the scaled solar term and a modified
  Lorentzian function also match the three cooler simulations reasonably
  well. <BR /> Conclusions: Three-dimensional radiation hydrodynamics
  simulations of near-surface convection can be averaged and combined with
  stellar structure models to better predict oscillation mode frequencies
  in solar-like oscillators. Our simplified results suggest that the
  surface effect is generally larger in hotter stars (and correspondingly
  smaller in cooler stars) and of similar shape in stars of solar type
  and cooler. However, we cannot presently predict whether this will
  remain so when other components of the surface effect are included.

Title: The global solar dynamo
Authors: Cameron, Robert
Bibcode: 2016cosp...41E.286C
Altcode:
  I will review our understanding of the solar dynamo, concentrating on
  how observations constrain the theoretical possibilities. Possibilities
  for future progress, including understanding the Sun in the
  solar-stellar context will be outlined.

Title: Solar activity in the coming decades
Authors: Cameron, Robert
Bibcode: 2016cosp...41E.287C
Altcode:
  I will discuss the current state of our understanding of the solar
  dynamo with an emphasis on the extent to which we can predict solar
  activity on timescales from years to decades. Possible paths which
  might lead to progress will be outlined and assessed.

Title: A low upper limit on the subsurface rise speed of solar
    active regions
Authors: Birch, A. C.; Schunker, H.; Braun, D. C.; Cameron, R.; Gizon,
   L.; Lo ptien, B.; Rempel, M.
Bibcode: 2016SciA....2E0557B
Altcode: 2016arXiv160705250B
  Magnetic field emerges at the surface of the Sun as sunspots and active
  regions. This process generates a poloidal magnetic field from a rising
  toroidal flux tube, it is a crucial but poorly understood aspect of
  the solar dynamo. The emergence of magnetic field is also important
  because it is a key driver of solar activity. We show that measurements
  of horizontal flows at the solar surface around emerging active regions,
  in combination with numerical simulations of solar magnetoconvection,
  can constrain the subsurface rise speed of emerging magnetic flux. The
  observed flows imply that the rise speed of the magnetic field is
  no larger than 150 m/s at a depth of 20 Mm, that is, well below the
  prediction of the (standard) thin flux tube model but in the range
  expected for convective velocities at this depth. We conclude that
  convective flows control the dynamics of rising flux tubes in the upper
  layers of the Sun and cannot be neglected in models of flux emergence.

Title: Surface flux transport simulations. Inflows towards active
    regions and the modulation of the solar cycle.
Authors: Martin-Belda, David; Cameron, Robert
Bibcode: 2016cosp...41E1255M
Altcode:
  Aims. We investigate the way near-surface converging flows
  towards active regions affect the build-up of magnetic field at
  the Sun's polar caps. In the Babcock-Leighton dynamo framework,
  this modulation of the polar fields could explain the variability of
  the solar cycle. Methods. We develop a surface flux transport code
  incorporating a parametrized model of the inflows and run simulations
  spanning several cycles. We carry out a parameter study to test how
  the strength and extension of the inflows affect the amplitude of the
  polar fields. Results. Inflows are seen to play an important role in
  the build-up of the polar fields, and can act as the non-linearity
  feedback mechanism required to limit the strength of the solar cycles
  in the Babcock-Leighton dynamo framework.

Title: The origin of Total Solar Irradiance variability on timescales
    less than a day
Authors: Shapiro, Alexander; Krivova, Natalie; Schmutz, Werner;
   Solanki, Sami K.; Leng Yeo, Kok; Cameron, Robert; Beeck, Benjamin
Bibcode: 2016cosp...41E1774S
Altcode:
  Total Solar Irradiance (TSI) varies on timescales from minutes to
  decades. It is generally accepted that variability on timescales of
  a day and longer is dominated by solar surface magnetic fields. For
  shorter time scales, several additional sources of variability have
  been proposed, including convection and oscillation. However, available
  simplified and highly parameterised models could not accurately explain
  the observed variability in high-cadence TSI records. We employed the
  high-cadence solar imagery from the Helioseismic and Magnetic Imager
  onboard the Solar Dynamics Observatory and the SATIRE (Spectral And
  Total Irradiance Reconstruction) model of solar irradiance variability
  to recreate the magnetic component of TSI variability. The recent 3D
  simulations of solar near-surface convection with MURAM code have been
  used to calculate the TSI variability caused by convection. This allowed
  us to determine the threshold timescale between TSI variability caused
  by the magnetic field and convection. Our model successfully replicates
  the TSI measurements by the PICARD/PREMOS radiometer which span the
  period of July 2010 to February 2014 at 2-minute cadence. Hence,
  we demonstrate that solar magnetism and convection can account for
  TSI variability at all timescale it has ever been measured (sans the
  5-minute component from p-modes).

Title: Solar Cycle 25: Another Moderate Cycle?
Authors: Cameron, R. H.; Jiang, J.; Schüssler, M.
Bibcode: 2016ApJ...823L..22C
Altcode: 2016arXiv160405405C
  Surface flux transport simulations for the descending phase of
  Cycle 24 using random sources (emerging bipolar magnetic regions)
  with empirically determined scatter of their properties provide a
  prediction of the axial dipole moment during the upcoming activity
  minimum together with a realistic uncertainty range. The expectation
  value for the dipole moment around 2020 (2.5 ± 1.1 G) is comparable
  to that observed at the end of Cycle 23 (about 2 G). The empirical
  correlation between the dipole moment during solar minimum and the
  strength of the subsequent cycle thus suggests that Cycle 25 will
  be of moderate amplitude, not much higher than that of the current
  cycle. However, the intrinsic uncertainty of such predictions resulting
  from the random scatter of the source properties is considerable and
  fundamentally limits the reliability with which such predictions can
  be made before activity minimum is reached.

Title: The turbulent diffusion of toroidal magnetic flux as inferred
    from properties of the sunspot butterfly diagram
Authors: Cameron, R. H.; Schüssler, M.
Bibcode: 2016A&A...591A..46C
Altcode: 2016arXiv160407340C
  Context. In order to match observed properties of the solar cycle,
  flux-transport dynamo models require the toroidal magnetic flux to be
  stored in a region of low magnetic diffusivity, typically located at
  or below the bottom of the convection zone. <BR /> Aims: We infer the
  turbulent magnetic diffusivity affecting the toroidal field on the basis
  of empirical data. <BR /> Methods: We considered the time evolution of
  mean latitude and width of the activity belts of solar cycles 12-23 and
  their dependence on cycle strength. We interpreted the decline phase
  of the cycles as a diffusion process. <BR /> Results: The activity
  level of a given cycle begins to decline when the centers of its
  equatorward propagating activity belts come within their (full) width
  (at half maximum) from the equator. This happens earlier for stronger
  cycles because their activity belts are wider. From that moment on, the
  activity and the belt width decrease in the same manner for all cycles,
  independent of their maximum activity level. In terms of diffusive
  cancellation of opposite-polarity toroidal flux across the equator,
  we infer the turbulent diffusivity experienced by the toroidal field,
  wherever it is located, to be in the range 150-450 km<SUP>2</SUP>
  s<SUP>-1</SUP>. Strong diffusive latitudinal spreading of the toroidal
  flux underneath the activity belts can be inhibited by an inflow toward
  the toroidal field bands in the convection zone with a magnitude of
  several meters per second. <BR /> Conclusions: The inferred value of
  the turbulent magnetic diffusivity affecting the toroidal field agrees,
  to order of magnitude, with estimates based on mixing-length models for
  the solar convection zone. This is at variance with the requirement of
  flux-transport dynamo models. The inflows required to keep the toroidal
  field bands together before they approach the equator are similar to the
  inflows toward the activity belts observed with local helioseismology.

Title: Statistical Differences in Time-Distance Helioseismology
    Results
Authors: Hess Webber, Shea A.; Pesnell, William D.; Duvall, Thomas;
   Cameron, Robert; Birch, A. C.
Bibcode: 2016SPD....4720301H
Altcode:
  Time-distance helioseismology studies phase correlations in solar wave
  modes. We use these techniques to investigate the phase differences in
  f-mode wave propagation within a coronal hole feature and without. We
  isolate the coronal hole boundary location using edge detection
  techniques on SDO AIA data. We then use this location information to
  inform the analysis of the corresponding HMI time-distance velocity
  tracked data product, provided by Stanford's JSOC archive. We look
  at time-distance results inside the coronal hole, outside the coronal
  hole, the coronal hole data as a whole, and an independent quiet sun
  region. We use Student's t-Test to evaluate the significance of the
  differences between the various regions.

Title: Babcock-Leighton solar dynamo: the role of downward pumping
    and the equatorward propagation of activity
Authors: Karak, Bidya Binay; Cameron, Robert
Bibcode: 2016SPD....47.0717K
Altcode:
  We investigate the role of downward magnetic pumping near the surface
  using a kinematic Babcock-Leighton model. We find that the pumping
  causes the poloidal field to become predominately radial in the
  near-surface shear layer. This allows the negative radial shear in the
  near-surface layer to effectively act on the radial field to produce a
  toroidal field. Consequently, we observe a clear equatorward migration
  of the toroidal field at low latitudes even when there is no meridional
  flow in the deep CZ. We show a case where the period of a dynamo wave
  solution is approximately 11 years. Flux transport models are also shown
  with periods close to 11 years. Both the dynamo wave and flux transport
  dynamo are thus able to reproduce some of the observed features of solar
  cycle. The main difference between the two types of dynamo is the value
  of $\alpha$ required to produce dynamo action. In both types of dynamo,
  the surface meridional flow helps to advect and build the polar field
  in high latitudes, while in flux transport dynamo the equatorward flow
  near the bottom of CZ advects toroidal field to cause the equatorward
  migration in butterfly wings and this advection makes the dynamo easier
  by transporting strong toroidal field to low latitudes where $\alpha$
  effect works. Another conclusion of our study is that the magnetic
  pumping suppresses the diffusion of fields through the photospheric
  surface which helps to achieve the 11-year dynamo cycle at a moderately
  larger value of magnetic diffusivity than has previously been used.

Title: Semi-empirical Long-term Reconstruction of the Heliospheric
Parameters: Validation by Cosmogenic Radionuclide Records
Authors: Asvestari, E.; Usoskin, I. G.; Cameron, R. H.; Krivova, N. A.
Bibcode: 2016ASPC..504..269A
Altcode:
  We have developed a semi-empirical model that describes the heliospheric
  modulation of galactic cosmic rays considering different heliospheric
  parameters. This model is an improvement of a previous model. The
  parameters of the model are fitted using the observations and
  reconstructions of the heliospheric parameters for the period 1976 -
  2013, which includes the latest very weak solar minimum. The modulation
  potential is computed since 1610 using different reconstructions of the
  open solar magnetic flux and it is then used to compute the production
  and distribution of cosmogenic isotope <SUP>14</SUP>C, which was
  subsequently compared with terrestrial archives in tree rings. It is
  shown that the group sunspot number series by Svalgaard &amp; Schatten
  (2015) is inconsistent with the data, while other series agree well.

Title: Surface flux transport simulations: Effect of inflows toward
    active regions and random velocities on the evolution of the Sun's
    large-scale magnetic field
Authors: Martin-Belda, D.; Cameron, R. H.
Bibcode: 2016A&A...586A..73M
Altcode: 2015arXiv151202541M
  <BR /> Aims: We aim to determine the effect of converging flows on
  the evolution of a bipolar magnetic region (BMR), and to investigate
  the role of these inflows in the generation of poloidal flux. We
  also discuss whether the flux dispersal due to turbulent flows can
  be described as a diffusion process. <BR /> Methods: We developed
  a simple surface flux transport model based on point-like magnetic
  concentrations. We tracked the tilt angle, the magnetic flux and the
  axial dipole moment of a BMR in simulations with and without inflows and
  compared the results. To test the diffusion approximation, simulations
  of random walk dispersal of magnetic features were compared against the
  predictions of the diffusion treatment. <BR /> Results: We confirm the
  validity of the diffusion approximation to describe flux dispersal on
  large scales. We find that the inflows enhance flux cancellation, but
  at the same time affect the latitudinal separation of the polarities
  of the bipolar region. In most cases the latitudinal separation is
  limited by the inflows, resulting in a reduction of the axial dipole
  moment of the BMR. However, when the initial tilt angle of the BMR
  is small, the inflows produce an increase in latitudinal separation
  that leads to an increase in the axial dipole moment in spite of the
  enhanced flux destruction. This can give rise to a tilt of the BMR
  even when the BMR was originally aligned parallel to the equator.

Title: Limitations of force-free magnetic field extrapolations:
    Revisiting basic assumptions
Authors: Peter, H.; Warnecke, J.; Chitta, L. P.; Cameron, R. H.
Bibcode: 2015A&A...584A..68P
Altcode: 2015arXiv151004642P
  Context. Force-free extrapolations are widely used to study the magnetic
  field in the solar corona based on surface measurements. <BR /> Aims:
  The extrapolations assume that the ratio of internal energy of the
  plasma to magnetic energy, the plasma β, is negligible. Despite the
  widespread use of this assumption observations, models, and theoretical
  considerations show that β is of the order of a few percent to more
  than 10%, and thus not small. We investigate what consequences this
  has for the reliability of extrapolation results. <BR /> Methods: We
  use basic concepts starting with force and energy balance to infer
  relations between plasma β and free magnetic energy to study the
  direction of currents in the corona with respect to the magnetic
  field, and to estimate the errors in the free magnetic energy by
  neglecting effects of the plasma (β ≪ 1). A comparison with a 3D
  magneto-hydrodynamics (MHD) model supports our basic considerations. <BR
  /> Results: If plasma β is of the order of the relative free energy
  (the ratio of the free magnetic energy to the total magnetic energy)
  then the pressure gradient can balance the Lorentz force. This is the
  case in solar corona, and therefore the currents are not properly
  described. In particular, the error in terms of magnetic energy by
  neglecting the plasma is of the order of the free magnetic energy, so
  that the latter cannot be reliably determined by an extrapolation. <BR
  /> Conclusions: While a force-free extrapolation might capture the
  magnetic structure and connectivity of the coronal magnetic field,
  the derived currents and free magnetic energy are not reliable. Thus
  quantitative results of extrapolations on the location and amount of
  heating in the corona (through current dissipation) and on the energy
  storage of the magnetic field (e.g. for eruptive events) are limited.

Title: Toward the construction of a medium size prototype
    Schwarzschild-Couder telescope for CTA
Authors: Rousselle, J.; Byrum, K.; Cameron, R.; Connaughton, V.;
   Errando, M.; Griffiths, S.; Guarino, V.; Humensky, T. B.; Jenke, P.;
   Kaaret, P.; Kieda, D.; Limon, M.; Mognet, I.; Mukherjee, R.; Nieto,
   D.; Okumura, A.; Peck, A.; Petrashyk, A.; Ribeiro, D.; Stevenson,
   B.; Vassiliev, V.; Yu, P.
Bibcode: 2015SPIE.9603E..05R
Altcode:
  The construction of a prototype Schwarzschild-Couder telescope (pSCT)
  started in early June 2015 at the Fred Lawrence Whipple Observatory
  in Southern Arizona, as a candidate medium-sized telescope for the
  Cherenkov Telescope Array (CTA). Compared to current Davies-Cotton
  telescopes, this novel instrument with an aplanatic two-mirror
  optical system will offer a wider field-of-view and improved angular
  resolution. In addition, the reduced plate scale of the camera
  allows the use of highly-integrated photon detectors such as silicon
  photo multipliers. As part of CTA, this design has the potential to
  greatly improve the performance of the next generation ground-based
  observatory for very high-energy (E&gt;60 GeV) gamma-ray astronomy. In
  this contribution we present the design and performance of both optical
  and alignment systems of the pSCT.

Title: Three-dimensional simulations of near-surface convection
    in main-sequence stars. III. The structure of small-scale magnetic
    flux concentrations
Authors: Beeck, B.; Schüssler, M.; Cameron, R. H.; Reiners, A.
Bibcode: 2015A&A...581A..42B
Altcode: 2015arXiv150504739B
  Context. The convective envelopes of cool main-sequence stars harbour
  magnetic fields with a complex global and local structure. These fields
  affect the near-surface convection and the outer stellar atmospheres
  in many ways and are responsible for the observable magnetic activity
  of stars. <BR /> Aims: Our aim is to understand the local structure in
  unipolar regions with moderate average magnetic flux density. These
  correspond to plage regions covering a substantial fraction of the
  surface of the Sun (and likely also the surface of other Sun-like stars)
  during periods of high magnetic activity. <BR /> Methods: We analyse
  the results of 18 local-box magnetohydrodynamics simulations covering
  the upper layers of the convection zones and the photospheres of cool
  main-sequence stars of spectral types F to early M. The average vertical
  field in these simulations ranges from 20 to 500 G. <BR /> Results:
  We find a substantial variation of the properties of the surface
  magnetoconvection between main-sequence stars of different spectral
  types. As a consequence of a reduced efficiency of the convective
  collapse of flux tubes, M dwarfs lack bright magnetic structures in
  unipolar regions of moderate field strength. The spatial correlation
  between velocity and the magnetic field as well as the lifetime
  of magnetic structures and their sizes relative to the granules
  vary significantly along the model sequence of stellar types. <P
  />Movies associated to Fig. A.1 are available in electronic form at <A
  href="http://www.aanda.org/10.1051/0004-6361/201525788/olm">http://www.aanda.org</A>

Title: Three-dimensional simulations of near-surface convection
    in main-sequence stars. IV. Effect of small-scale magnetic flux
    concentrations on centre-to-limb variation and spectral lines
Authors: Beeck, B.; Schüssler, M.; Cameron, R. H.; Reiners, A.
Bibcode: 2015A&A...581A..43B
Altcode: 2015arXiv150504744B
  Context. Magnetic fields affect the local structure of the photosphere
  of stars. They can considerably influence the radiative properties near
  the optical surface, flow velocities, and the temperature and pressure
  profiles. This has an impact on observables such as limb darkening
  and spectral line profiles. <BR /> Aims: We aim at understanding
  qualitatively the influence of small magnetic flux concentrations
  in unipolar plage regions on the centre-to-limb variation of
  the intensity and its contrast and on the shape of spectral line
  profiles in cool main-sequence stars. <BR /> Methods: We analyse
  the bolometric and continuum intensity and its angular dependence
  of 24 radiative magnetohydrodynamic simulations of the near-surface
  layers of main-sequence stars with six different sets of stellar
  parameters (spectral types F to early M) and four different average
  magnetic field strengths (including the non-magnetic case). We also
  calculated disc-integrated profiles of three spectral lines. <BR />
  Results: The small magnetic flux concentrations formed in the magnetic
  runs of simulations have a considerable impact on the intensity and
  its centre-to-limb variation. In some cases, the difference in limb
  darkening between magnetic and non-magnetic runs is larger than the
  difference between the spectral types. Spectral lines are not only
  broadened owing to the Zeeman effect, but are also strongly affected by
  the modified thermodynamical structure and flow patterns. This indirect
  magnetic impact on the line profiles is often bigger than that of the
  Zeeman effect. <BR /> Conclusions: The effects of the magnetic field on
  the radiation leaving the star can be considerable and is not restricted
  to spectral line broadening and polarisation by the Zeeman effect. The
  inhomogeneous structure of the magnetic field on small length scales and
  its impact on (and spatial correlation with) the local thermodynamical
  structure and the flow field near the surface influence the measurement
  of the global field properties and stellar parameters. These
  effects need to be taken into account in the interpretation of
  observations. <P />Appendix A is available in electronic form at <A
  href="http://www.aanda.org/10.1051/0004-6361/201525874/olm">http://www.aanda.org</A>

Title: A Medium Sized Schwarzschild-Couder Cherenkov Telescope
    Mechanical Design Proposed for the Cherenkov Telescope Array
Authors: Byrum, K.; Humensky, T. B.; Benbow, W.; Cameron, R.; Criswell,
   S.; Errando, M.; Guarino, V.; Kaaret, P.; Kieda, D.; Mukherjee,
   R.; Naumann, D.; Nieto, D.; Northrop, R.; Okumura, A.; Roache, E.;
   Rousselle, J.; Schlenstedt, S.; Sternberger, R.; Vassiliev, V.;
   Wakely, S.; Zhao, H.
Bibcode: 2015arXiv150903074B
Altcode:
  The Cherenkov Telescope Array (CTA) is an international next-generation
  ground-based gamma-ray observatory. CTA will be implemented as southern
  and northern hemisphere arrays of tens of small, medium and large-sized
  imaging Cherenkov telescopes with the goal of improving the sensitivity
  over the current-generation experiments by an order of magnitude. CTA
  will provide energy coverage from ~20 GeV to more than 300 TeV. The
  Schwarzschild-Couder (SC) medium size (9.5m) telescopes will feature
  a novel aplanatic two-mirror optical design capable of accommodating
  a wide field-of-view with significantly improved angular resolution as
  compared to the traditional Davies-Cotton optical design. A full-scale
  prototype SC medium size telescope structure has been designed and will
  be constructed at the Fred Lawrence Whipple Observatory in southern
  Arizona during the fall of 2015. concentrate on the novel features of
  the design.

Title: CTA Contributions to the 34th International Cosmic Ray
    Conference (ICRC2015)
Authors: CTA Consortium, The; :; Abchiche, A.; Abeysekara, U.; Abril,
   Ó.; Acero, F.; Acharya, B. S.; Actis, M.; Agnetta, G.; Aguilar,
   J. A.; Aharonian, F.; Akhperjanian, A.; Albert, A.; Alcubierre,
   M.; Alfaro, R.; Aliu, E.; Allafort, A. J.; Allan, D.; Allekotte,
   I.; Aloisio, R.; Amans, J. -P.; Amato, E.; Ambrogi, L.; Ambrosi, G.;
   Ambrosio, M.; Anderson, J.; Anduze, M.; Angüner, E. O.; Antolini, E.;
   Antonelli, L. A.; Antonucci, M.; Antonuccio, V.; Antoranz, P.; Aramo,
   C.; Aravantinos, A.; Argan, A.; Armstrong, T.; Arnaldi, H.; Arnold, L.;
   Arrabito, L.; Arrieta, M.; Arrieta, M.; Asano, K.; Asorey, H. G.; Aune,
   T.; Singh, C. B.; Babic, A.; Backes, M.; Bais, A.; Bajtlik, S.; Balazs,
   C.; Balbo, M.; Balis, D.; Balkowski, C.; Ballester, O.; Ballet, J.;
   Balzer, A.; Bamba, A.; Bandiera, R.; Barber, A.; Barbier, C.; Barceló,
   M.; Barnacka, A.; Barres de Almeida, U.; Barrio, J. A.; Basso, S.;
   Bastieri, D.; Bauer, C.; Baushev, A.; Becciani, U.; Becherini, Y.;
   Becker Tjus, J.; Beckmann, V.; Bednarek, W.; Benbow, W.; Benedico
   Ventura, D.; Berdugo, J.; Berge, D.; Bernardini, E.; Bernhard, S.;
   Bernlöhr, K.; Bertucci, B.; Besel, M. -A.; Bhatt, N.; Bhattacharjee,
   P.; Bhattachryya, S.; Biasuzzi, B.; Bicknell, G.; Bigongiari, C.;
   Biland, A.; Billotta, S.; Bilnik, W.; Biondo, B.; Bird, T.; Birsin,
   E.; Bissaldi, E.; Biteau, J.; Bitossi, M.; Blanch Bigas, O.; Blasi,
   P.; Boehm, C.; Bogacz, L.; Bogdan, M.; Bohacova, M.; Boisson, C.;
   Boix Gargallo, J.; Bolmont, J.; Bonanno, G.; Bonardi, A.; Bonifacio,
   P.; Bonnoli, G.; Borkowski, J.; Bose, R.; Bosnjak, Z.; Bottani, A.;
   Böttcher, M.; Bousquet, J. -J.; Boutonnet, C.; Bouyjou, F.; Braiding,
   C.; Brandt, L.; Brau-Nogué, S.; Bregeon, J.; Bretz, T.; Briggs,
   M.; Brigida, M.; Bringmann, T.; Brisken, W.; Brocato, E.; Brook, P.;
   Brown, A. M.; Brun, P.; Brunetti, G.; Brunetti, L.; Bruno, P.; Bryan,
   M.; Buanes, T.; Bucciantini, N.; Buchholtz, G.; Buckley, J.; Bugaev,
   V.; Bühler, R.; Bulgarelli, A.; Bulik, T.; Burton, M.; Burtovoi, A.;
   Busetto, G.; Buson, S.; Buss, J.; Byrum, K.; Cameron, R.; Camprecios,
   J.; Canelli, F.; Canestrari, R.; Cantu, S.; Capalbi, M.; Capasso, M.;
   Capobianco, G.; Caraveo, P.; Cardenzana, J.; Carius, S.; Carlile, C.;
   Carmona, E.; Carosi, A.; Carosi, R.; Carr, J.; Carroll, M.; Carter,
   J.; Carton, P. -H.; Caruso, R.; Casandjian, J. -M.; Casanova, S.;
   Cascone, E.; Casiraghi, M.; Castellina, A.; Catalano, O.; Catalanotti,
   S.; Cavazzani, S.; Cazaux, S.; Cefalà, M.; Cerchiara, P.; Cereda,
   M.; Cerruti, M.; Chabanne, E.; Chadwick, P.; Champion, C.; Chaty,
   S.; Chaves, R.; Cheimets, P.; Chen, A.; Chen, X.; Chernyakova, M.;
   Chiappetti, L.; Chikawa, M.; Chinn, D.; Chitnis, V. R.; Cho, N.;
   Christov, A.; Chudoba, J.; Cieślar, M.; Cillis, A.; Ciocci, M. A.;
   Clay, R.; Cohen-Tanugi, J.; Colafrancesco, S.; Colin, P.; Colombo,
   E.; Colome, J.; Colonges, S.; Compin, M.; Conforti, V.; Connaughton,
   V.; Connell, S.; Conrad, J.; Contreras, J. L.; Coppi, P.; Corbel, S.;
   Coridian, J.; Corona, P.; Corti, D.; Cortina, J.; Cossio, L.; Costa,
   A.; Costantini, H.; Cotter, G.; Courty, B.; Covino, S.; Covone, G.;
   Crimi, G.; Criswell, S. J.; Crocker, R.; Croston, J.; Cusumano, G.;
   Da Vela, P.; Dale, Ø.; D'Ammando, F.; Dang, D.; Daniel, M.; Davids,
   I.; Dawson, B.; Dazzi, F.; de Aguiar Costa, B.; De Angelis, A.; de
   Araujo Cardoso, R. F.; De Caprio, V.; De Cesare, G.; De Franco, A.;
   De Frondat, F.; de Gouveia Dal Pino, E. M.; de la Calle, I.; De La
   Vega, G. A.; de los Reyes Lopez, R.; De Lotto, B.; De Luca, A.; de
   Mello Neto, J. R. T.; de Naurois, M.; de Oña Wilhelmi, E.; De Palma,
   F.; de Souza, V.; Decock, G.; Deil, C.; Del Santo, M.; Delagnes, E.;
   Deleglise, G.; Delgado, C.; della Volpe, D.; Deloye, P.; Depaola, G.;
   Detournay, M.; Dettlaff, A.; Di Girolamo, T.; Di Giulio, C.; Di Paola,
   A.; Di Pierro, F.; Di Sciascio, G.; Díaz, C.; Dick, J.; Dickinson, H.;
   Diebold, S.; Diez, V.; Digel, S.; Dipold, J.; Disset, G.; Distefano,
   A.; Djannati-Ataï, A.; Doert, M.; Dohmke, M.; Domainko, W.; Dominik,
   N.; Dominis Prester, D.; Donat, A.; Donnarumma, I.; Dorner, D.; Doro,
   M.; Dournaux, J. -L.; Doyle, K.; Drake, G.; Dravins, D.; Drury, L.;
   Dubus, G.; Dumas, D.; Dumm, J.; Durand, D.; D'Urso, D.; Dwarkadas,
   V.; Dyks, J.; Dyrda, M.; Ebr, J.; Echaniz, J. C.; Edy, E.; Egberts,
   K.; Egberts, K.; Eger, P.; Einecke, S.; Eisch, J.; Eisenkolb, F.;
   Eleftheriadis, C.; Elsässer, D.; Emmanoulopoulos, D.; Engelbrecht,
   C.; Engelhaupt, D.; Ernenwein, J. -P.; Errando, M.; Eschbach, S.;
   Etchegoyen, A.; Evans, P.; Fairbairn, M.; Falcone, A.; Fantinel, D.;
   Farakos, K.; Farnier, C.; Farrell, E.; Farrell, S.; Fasola, G.; Fegan,
   S.; Feinstein, F.; Ferenc, D.; Fernandez, A.; Fernandez-Alonso, M.;
   Ferreira, O.; Fesquet, M.; Fetfatzis, P.; Fiasson, A.; Filipčič, A.;
   Filipovic, M.; Fink, D.; Finley, C.; Finley, J. P.; Finoguenov, A.;
   Fioretti, V.; Fiorini, M.; Firpo Curcoll, R.; Fleischhack, H.; Flores,
   H.; Florin, D.; Föhr, C.; Fokitis, E.; Font, L.; Fontaine, G.; Fontes,
   B.; Forest, F.; Fornasa, M.; Förster, A.; Fortin, P.; Fortson, L.;
   Fouque, N.; Franckowiak, A.; Franco, F. J.; Frankowski, A.; Frega,
   N.; Freire Mota Albuquerque, I.; Freixas Coromina, L.; Fresnillo,
   L.; Fruck, C.; Fuessling, M.; Fugazza, D.; Fujita, Y.; Fukami, S.;
   Fukazawa, Y.; Fukuda, T.; Fukui, Y.; Funk, S.; Gäbele, W.; Gabici,
   S.; Gadola, A.; Galante, N.; Gall, D. D.; Gallant, Y.; Galloway, D.;
   Gallozzi, S.; Gao, S.; Garcia, B.; García Gil, R.; Garcia López,
   R.; Garczarczyk, M.; Gardiol, D.; Gargano, C.; Gargano, F.; Garozzo,
   S.; Garrecht, F.; Garrido, D.; Garrido, L.; Gascon, D.; Gaskins,
   J.; Gaudemard, J.; Gaug, M.; Gaweda, J.; Geffroy, N.; Gérard, L.;
   Ghalumyan, A.; Ghedina, A.; Ghigo, M.; Ghislain, P.; Giannakaki, E.;
   Gianotti, F.; Giarrusso, S.; Giavitto, G.; Giebels, B.; Giglietto,
   N.; Gika, V.; Gimenes, R.; Giomi, M.; Giommi, P.; Giordano, F.;
   Giovannini, G.; Giro, E.; Giroletti, M.; Giuliani, A.; Glicenstein,
   J. -F.; Godinovic, N.; Goldoni, P.; Gomez Berisso, M.; Gomez Vargas,
   G. A.; Gonzalez, M. M.; González, A.; González, F.; González
   Muñoz, A.; Gothe, K. S.; Gotz, D.; Grabarczyk, T.; Graciani, R.;
   Grandi, P.; Grañena, F.; Granot, J.; Grasseau, G.; Gredig, R.;
   Green, A. J.; Green, A. M.; Greenshaw, T.; Grenier, I.; Grillo, A.;
   Grondin, M. -H.; Grube, J.; Grudzinska, M.; Grygorczuk, J.; Guarino,
   V.; Guberman, D.; Gunji, S.; Gyuk, G.; Hadasch, D.; Hagedorn, A.;
   Hahn, J.; Hakansson, N.; Hamer Heras, N.; Hanabata, Y.; Hara, S.;
   Hardcastle, M. J.; Harris, J.; Hassan, T.; Hatanaka, K.; Haubold,
   T.; Haupt, A.; Hayakawa, T.; Hayashida, M.; Heller, M.; Heller, R.;
   Henault, F.; Henri, G.; Hermann, G.; Hermel, R.; Herrera Llorente, J.;
   Herrero, A.; Hervet, O.; Hidaka, N.; Hinton, J.; Hirai, W.; Hirotani,
   K.; Hoard, D.; Hoffmann, D.; Hofmann, W.; Hofverberg, P.; Holch, T.;
   Holder, J.; Hooper, S.; Horan, D.; Hörandel, J. R.; Hormigos, S.;
   Horns, D.; Hose, J.; Houles, J.; Hovatta, T.; Hrabovsky, M.; Hrupec,
   D.; Huet, J. -M.; Hütten, M.; Humensky, T. B.; Huovelin, J.; Huppert,
   J. -F.; Iacovacci, M.; Ibarra, A.; Idźkowski, B.; Ikawa, D.; Illa,
   J. M.; Impiombato, D.; Incorvaia, S.; Inome, Y.; Inoue, S.; Inoue,
   T.; Inoue, Y.; Iocco, F.; Ioka, K.; Iori, M.; Ishio, K.; Israel,
   G. L.; Jablonski, C.; Jacholkowska, A.; Jacquemier, J.; Jamrozy,
   M.; Janecek, P.; Janiak, M.; Jankowsky, F.; Jean, P.; Jeanney, C.;
   Jegouzo, I.; Jenke, P.; Jimenez, J. J.; Jingo, M.; Jingo, M.; Jocou,
   L.; Jogler, T.; Johnson, C. A.; Journet, L.; Juffroy, C.; Jung,
   I.; Kaaret, P. E.; Kagaya, M.; Kakuwa, J.; Kalekin, O.; Kalkuhl, C.;
   Kankanyan, R.; Karastergiou, A.; Kärcher, K.; Karczewski, M.; Karkar,
   S.; Karn, P.; Kasperek, J.; Katagiri, H.; Kataoka, J.; Katarzyński,
   K.; Katz, U.; Kaufmann, S.; Kawanaka, N.; Kawashima, T.; Kazanas,
   D.; Kelley-Hoskins, N.; Kellner-Leidel, B.; Kendziorra, E.; Kersten,
   J.; Khélifi, B.; Kieda, D. B.; Kihm, T.; Kisaka, S.; Kissmann, R.;
   Klepser, S.; Kluźniak, W.; Knapen, J.; Knapp, J.; Knödlseder, J.;
   Köck, F.; Kocot, J.; Kodakkadan, A.; Kodani, K.; Kohri, K.; Kojima,
   T.; Kokkotas, K.; Kolitzus, D.; Komin, N.; Kominis, I.; Konno, Y.;
   Kosack, K.; Koss, G.; Koul, R.; Kowal, G.; Koyama, S.; Kozioł,
   J.; Kraus, M.; Krause, J.; Krause, M.; Krawzcynski, H.; Krennrich,
   F.; Kretzschmann, A.; Kruger, P.; Kubo, H.; Kudryavtsev, V.; Kukec
   Mezek, G.; Kushida, J.; Kuznetsov, A.; La Barbera, A.; La Palombara,
   N.; La Parola, V.; La Rosa, G.; Laffon, H.; Lagadec, T.; Lahmann,
   R.; Lalik, K.; Lamanna, G.; Landriu, D.; Landt, H.; Lang, R. G.;
   Languignon, D.; Lapington, J.; Laporte, P.; Latovski, N.; Law-Green,
   D.; Le Fèvre, J. -P.; Le Flour, T.; Le Sidaner, P.; Lee, S. -H.; Lee,
   W. H.; Leffhalm, K.; Leich, H.; Leigui de Oliveira, M. A.; Lelas,
   D.; Lemière, A.; Lemoine-Goumard, M.; Lenain, J. -P.; Leonard, R.;
   Leoni, R.; Lessio, L.; Leto, G.; Leveque, A.; Lieunard, B.; Limon,
   M.; Lindemann, R.; Lindfors, E.; Liolios, A.; Lipniacka, A.; Lockart,
   H.; Lohse, T.; Loiseau, D.; Łokas, E.; Lombardi, S.; Longo, F.;
   Longo, G.; Lopatin, A.; Lopez, M.; López-Coto, R.; López-Oramas,
   A.; Loreggia, D.; Louge, T.; Louis, F.; Lu, C. -C.; Lucarelli, F.;
   Lucchesi, D.; Lüdecke, H.; Luque-Escamilla, P. L.; Luz, O.; Lyard,
   E.; Maccarone, M. C.; Maccarone, T. J.; Mach, E.; Madejski, G. M.;
   Madonna, A.; Mahabir, M.; Maier, G.; Majumdar, P.; Makariev, M.;
   Malaguti, G.; Malaspina, G.; Mallot, A. K.; Maltezos, S.; Mancilla,
   A.; Mandat, D.; Maneva, G.; Manigot, P.; Mankushiyil, N.; Mannheim,
   K.; Maragos, N.; Marano, D.; Marchegiani, P.; Marcomini, J. A.;
   Marcowith, A.; Mariotti, M.; Marisaldi, M.; Markoff, S.; Marszałek,
   A.; Martens, C.; Martí, J.; Martin, J. -M.; Martin, P.; Martínez, G.;
   Martínez, M.; Martínez, O.; Marx, R.; Massimino, P.; Mastichiadis,
   A.; Mastroianni, S.; Mastropietro, M.; Masuda, S.; Matsumoto, H.;
   Matsuoka, S.; Mattiazzo, S.; Maurin, G.; Maxted, N.; Maya, J.; Mayer,
   M.; Mazin, D.; Mazureau, E.; Mazziotta, M. N.; Mc Comb, L.; McCann,
   A.; McCubbin, N.; McHardy, I.; McKay, R.; McKinney, K.; Meagher, K.;
   Medina, C.; Mehrez, F.; Melioli, C.; Melkumyan, D.; Melo, D.; Melse,
   T.; Mereghetti, S.; Mertsch, P.; Meyer, M.; Meyrelles, J. L., jr;
   Miccichè, A.; Michałowski, J.; Micolon, P.; Mientjes, P.; Mignot,
   S.; Mihailidis, A.; Mineo, T.; Minuti, M.; Mirabal, N.; Mirabel, F.;
   Miranda, J. M.; Mirzoyan, R.; Mistò, A.; Mitchell, A.; Mizuno, T.;
   Moderski, R.; Mognet, I.; Mohammed, M.; Moharana, R.; Molinari, E.;
   Monmarthe, E.; Monnier, G.; Montaruli, T.; Monte, C.; Monteiro, I.;
   Moore, P.; Moralejo Olaizola, A.; Morello, C.; Moretti, E.; Mori,
   K.; Morlino, G.; Morselli, A.; Mottez, F.; Moudden, Y.; Moulin, E.;
   Mrusek, I.; Mueller, S.; Mukherjee, R.; Munar-Adrover, P.; Mundell,
   C.; Muraishi, H.; Murase, K.; Muronga, A.; Murphy, A.; Nagataki,
   S.; Nagayoshi, T.; Nagesh, B. K.; Naito, T.; Nakajima, D.; Nakamori,
   T.; Nakayama, K.; Naumann, D.; Nayman, P.; Nellen, L.; Nemmen, R.;
   Neronov, A.; Neustroev, V.; Neyroud, N.; Nguyen, T.; Nicastro,
   L.; Nicolau-Kukliński, J.; Niederwanger, F.; Niedźwiecki, A.;
   Niemiec, J.; Nieto, D.; Nievas, M.; Nikolaidis, A.; Nishijima, K.;
   Nishikawa, K. -I.; Noda, K.; Nogues, L.; Nolan, S.; Northrop, R.;
   Nosek, D.; Nozka, L.; Nunio, F.; Oakes, L.; O'Brien, P.; Occhipinti,
   G.; O'Faolain de Bhroithe, A.; Ogino, M.; Ohira, Y.; Ohishi, M.; Ohm,
   S.; Ohoka, H.; Okumura, A.; Olive, J. -F.; Olszowski, D.; Ong, R. A.;
   Ono, S.; Orienti, M.; Orito, R.; Orlati, A.; Orlati, A.; Osborne, J.;
   Ostrowski, M.; Otero, L. A.; Ottaway, D.; Otte, N.; Oya, I.; Ozieblo,
   A.; Padovani, M.; Pagano, I.; Paiano, S.; Paizis, A.; Palacio, J.;
   Palatka, M.; Pallotta, J.; Panagiotidis, K.; Panazol, J. -L.; Paneque,
   D.; Panter, M.; Panzera, M. R.; Paoletti, R.; Paolillo, M.; Papayannis,
   A.; Papyan, G.; Paravac, A.; Paredes, J. M.; Pareschi, G.; Park, N.;
   Parsons, D.; Paśko, P.; Pavy, S.; Arribas, M. Paz; Pech, M.; Peck,
   A.; Pedaletti, G.; Peet, S.; Pelassa, V.; Pelat, D.; Peres, C.;
   Perez, M. d. C.; Perri, L.; Persic, M.; Petrashyk, A.; Petrucci,
   P. -O.; Peyaud, B.; Pfeifer, M.; Pfeiffer, G.; Piano, G.; Pichel,
   A.; Pieloth, D.; Pierbattista, M.; Pierre, E.; Pinto de Pinho, F.;
   García, C. Pio; Piret, Y.; Pita, S.; Planes, A.; Platino, M.; Platos,
   Ł.; Platzer, R.; Podkladkin, S.; Pogosyan, L.; Pohl, M.; Poinsignon,
   P.; Ponz, J. D.; Porcelli, A.; Potter, W.; Poulios, S.; Poutanen,
   J.; Prandini, E.; Prast, J.; Preece, R.; Profeti, F.; Prokhorov, D.;
   Prokoph, H.; Prouza, M.; Proyetti, M.; Pruchniewicz, R.; Pueschel,
   E.; Pühlhofer, G.; Puljak, I.; Punch, M.; Pyzioł, R.; Queiroz,
   F.; Quel, E. J.; Quinn, J.; Quirrenbach, A.; Racero, E.; Räck,
   T.; Rafalski, J.; Rafighi, I.; Rainò, S.; Rajda, P. J.; Rameez, M.;
   Rando, R.; Rannot, R. C.; Rataj, M.; Rateau, S.; Ravel, T.; Ravignani,
   D.; Razzaque, S.; Reardon, P.; Reimann, O.; Reimer, A.; Reimer, O.;
   Reitberger, K.; Renaud, M.; Renner, S.; Reposeur, T.; Rettig, R.;
   Reville, B.; Rhode, W.; Ribeiro, D.; Ribó, M.; Richards, G.; Richer,
   M. G.; Rico, J.; Ridky, J.; Rieger, F.; Ringegni, P.; Ristori, P. R.;
   Rivière, A.; Rivoire, S.; Roache, E.; Rodeghiero, G.; Rodriguez,
   J.; Rodriguez Fernandez, G.; Rodríguez Vázquez, J. J.; Rogers, T.;
   Rojas, G.; Romano, P.; Romay Rodriguez, M. P.; Romeo, G.; Romero,
   G. E.; Roncadelli, M.; Rose, J.; Rosen, S.; Rosier Lees, S.; Ross,
   D.; Rossiter, P.; Rouaix, G.; Rousselle, J.; Rovero, A. C.; Rowell,
   G.; Roy, F.; Royer, S.; Różańska, A.; Rudak, B.; Rugliancich,
   A.; Rulten, C.; Rupiński, M.; Russo, F.; Rutkowski, K.; Saavedra,
   O.; Sabatini, S.; Sacco, B.; Saemann, E. O.; Saggion, A.; Saha, L.;
   Sahakian, V.; Saito, K.; Saito, T.; Sakaki, N.; Salega, M.; Salek, D.;
   Salgado, J.; Salini, A.; Sanchez, D.; Sanchez, F.; Sanchez-Conde, M.;
   Sandaker, H.; Sandoval, A.; Sangiorgi, P.; Sanguillon, M.; Sano, H.;
   Santander, M.; Santangelo, A.; Santos, E. M.; Santos-Lima, R.; Sanuy,
   A.; Sapozhnikov, L.; Sarkar, S.; Satalecka, K.; Savalle, R.; Sawada,
   M.; Sayède, F.; Schafer, J.; Schanne, S.; Schanz, T.; Schioppa, E. J.;
   Schlenstedt, S.; Schlickeiser, R.; Schmidt, T.; Schmoll, J.; Schneider,
   M.; Schovanek, P.; Schubert, A.; Schultz, C.; Schultze, J.; Schulz,
   A.; Schulz, S.; Schure, K.; Schussler, F.; Schwab, T.; Schwanke, U.;
   Schwarz, J.; Schweizer, T.; Schwemmer, S.; Schwendicke, U.; Schwerdt,
   C.; Segreto, A.; Seiradakis, J. -H.; Sembroski, G. H.; Semikoz, D.;
   Serre, N.; Servillat, M.; Seweryn, K.; Shafi, N.; Sharma, M.; Shayduk,
   M.; Shellard, R. C.; Shibata, T.; Shiningayamwe Pandeni, K.; Shukla,
   A.; Shum, E.; Sidoli, L.; Sidz, M.; Sieiro, J.; Siejkowski, H.; Silk,
   J.; Sillanpää, A.; Simone, D.; Singh, B. B.; Sinha, A.; Sironi, G.;
   Sitarek, J.; Sizun, P.; Slyusar, V.; Smith, A.; Smith, J.; Sobczyńska,
   D.; Sol, H.; Sottile, G.; Sowiński, M.; Spanier, F.; Spengler, G.;
   Spiga, D.; Stadler, R.; Stahl, O.; Stamatescu, V.; Stamerra, A.;
   Stanič, S.; Starling, R.; Stawarz, Ł.; Steenkamp, R.; Stefanik, S.;
   Stegmann, C.; Steiner, S.; Stella, C.; Stergioulas, N.; Sternberger,
   R.; Sterzel, M.; Stevenson, B.; Stinzing, F.; Stodulska, M.; Stodulski,
   M.; Stolarczyk, T.; Straumann, U.; Strazzeri, E.; Stringhetti, L.;
   Strzys, M.; Stuik, R.; Sulanke, K. -H.; Supanitsky, A. D.; Suric, T.;
   Sushch, I.; Sutcliffe, P.; Sykes, J.; Szanecki, M.; Szepieniec, T.;
   Szwarnog, P.; Tacchini, A.; Tachihara, K.; Tagliaferri, G.; Tajima, H.;
   Takahashi, H.; Takahashi, K.; Takahashi, M.; Takalo, L.; Takami, H.;
   Talbot, G.; Tammi, J.; Tanaka, M.; Tanaka, S.; Tanaka, T.; Tanaka, Y.;
   Tanci, C.; Tarantino, E.; Tavani, M.; Tavecchio, F.; Tavernet, J. -P.;
   Tayabaly, K.; Tejedor, L. A.; Telezhinsky, I.; Temme, F.; Temnikov, P.;
   Tenzer, C.; Terada, Y.; Terrier, R.; Tescaro, D.; Teshima, M.; Testa,
   V.; Tezier, D.; Thayer, J.; Thomas, V.; Thornhill, J.; Thuermann,
   D.; Tibaldo, L.; Tibolla, O.; Tiengo, A.; Tijsseling, G.; Timpanaro,
   M. C.; Tluczykont, M.; Todero Peixoto, C. J.; Tokanai, F.; Tokarz, M.;
   Toma, K.; Toma, K.; Tomastik, J.; Tomono, Y.; Tonachini, A.; Tonev,
   D.; Torii, K.; Tornikoski, M.; Torres, D. F.; Torres, M.; Torresi, E.;
   Toscano, S.; Toso, G.; Tosti, G.; Totani, T.; Tothill, N.; Toussenel,
   F.; Tovmassian, G.; Townsley, C.; Toyama, T.; Travnicek, P.; Trifoglio,
   M.; Troyano Pujadas, I.; Troyano Pujadas, I.; Trzeciak, M.; Tsinganos,
   K.; Tsubone, Y.; Tsuchiya, Y.; Tsujimoto, S.; Tsuru, T.; Uchiyama, Y.;
   Umana, G.; Umetsu, Y.; Underwood, C.; Upadhya, S. S.; Uslenghi, M.;
   Vagnetti, F.; Valdes-Galicia, J.; Vallania, P.; Vallejo, G.; Valore,
   L.; van Driel, W.; van Eldik, C.; van Soelen, B.; Vandenbroucke, J.;
   Vanderwalt, J.; Vasileiadis, G.; Vassiliev, V.; Vázquez Acosta,
   M. L.; Vecchi, M.; Vegas, I.; Veitch, P.; Venema, L.; Venter, C.;
   Vercellone, S.; Vergani, S.; Verma, K.; Verzi, V.; Vettolani, G. P.;
   Viana, A.; Vicha, J.; Videla, M.; Vigorito, C.; Vincent, P.; Vincent,
   S.; Vink, J.; Vittorini, V.; Vlahakis, N.; Vlahos, L.; Voelk, H.;
   Vogler, P.; Voisin, V.; Vollhardt, A.; Volpicelli, A.; Vorobiov,
   S.; Vovk, I.; Vu, L. V.; Wagner, R.; Wagner, R. M.; Wagner, R. G.;
   Wagner, S. J.; Wakely, S. P.; Walter, R.; Walther, T.; Ward, J. E.;
   Ward, M.; Warda, K.; Warwick, R.; Wassberg, S.; Watson, J.; Wawer,
   P.; Wawrzaszek, R.; Webb, N.; Wegner, P.; Weinstein, A.; Weitzel, Q.;
   Wells, R.; Werner, F.; Werner, M.; Wetteskind, H.; White, M.; White,
   R.; Więcek, M.; Wierzcholska, A.; Wiesand, S.; Wijers, R.; Wild, N.;
   Wilhelm, A.; Wilkinson, M.; Will, M.; Williams, D. A.; Williams, J. T.;
   Willingale, R.; Winde, M.; Winiarski, K.; Winkler, H.; Wischnewski,
   R.; Wojcik, P.; Wolf, D.; Wood, M.; Wörnlein, A.; Wu, E.; Wu, T.;
   Yadav, K. K.; Yamamoto, H.; Yamamoto, T.; Yamazaki, R.; Yanagita, S.;
   Yang, L.; Yebras, J. M.; Yelos, D.; Yeung, W.; Yoshida, A.; Yoshida,
   T.; Yoshiike, S.; Yoshikoshi, T.; Yu, P.; Zabalza, V.; Zabalza, V.;
   Zacharias, M.; Zaharijas, G.; Zajczyk, A.; Zampieri, L.; Zandanel,
   F.; Zanin, R.; Zanmar Sanchez, R.; Zavrtanik, D.; Zavrtanik, M.;
   Zdziarski, A.; Zech, A.; Zechlin, H.; Zhao, A.; Ziegler, A.; Ziemann,
   J.; Ziętara, K.; Ziółkowski, J.; Zitelli, V.; Zoli, A.; Zurbach,
   C.; Żychowski, P.
Bibcode: 2015arXiv150805894C
Altcode:
  List of contributions from the CTA Consortium presented at the 34th
  International Cosmic Ray Conference, 30 July - 6 August 2015, The Hague,
  The Netherlands.

Title: The Cause of the Weak Solar Cycle 24
Authors: Jiang, J.; Cameron, R. H.; Schüssler, M.
Bibcode: 2015ApJ...808L..28J
Altcode: 2015arXiv150701764J
  The ongoing 11 year cycle of solar activity is considerably less
  vigorous than the three cycles before. It was preceded by a very deep
  activity minimum with a low polar magnetic flux, the source of the
  toroidal field responsible for solar magnetic activity in the subsequent
  cycle. Simulation of the evolution of the solar surface field shows
  that the weak polar fields and thus the weakness of the present cycle
  24 are mainly caused by a number of bigger bipolar regions emerging at
  low latitudes with a “wrong” (i.e., opposite to the majority for
  this cycle) orientation of their magnetic polarities in the north-south
  direction, which impaired the growth of the polar field. These regions
  had a particularly strong effect since they emerged within +/- 10^\circ
  latitude from the solar equator.

Title: Construction of a Schwarzschild-Couder telescope as a candidate
for the Cherenkov Telescope Array: Implementation of the opti
Authors: Rousselle, J.; Byrum, K.; Cameron, R.; Connaughton, V.;
   Errando, M.; Guarino, V.; Humensky, B.; Jenke, P.; Kieda, D.;
   Mukherjee, R.; Nieto Castano, D.; Okumura, A.; Petrashyk, A.;
   Vassiliev, V.
Bibcode: 2015ICRC...34..938R
Altcode: 2015PoS...236..938R; 2015arXiv150901143R
  We present the design and the status of procurement of the optical
  system of the prototype Schwarzschild-Couder telescope (pSCT), for
  which construction is scheduled to begin in fall at the Fred Lawrence
  Whipple Observatory in southern Arizona, USA. The Schwarzschild-Couder
  telescope is a candidate for the medium-sized telescopes of the
  Cherenkov Telescope Array, which utilizes imaging atmospheric
  Cherenkov techniques to observe gamma rays in the energy range of
  60Gev-60TeV. The pSCT novel aplanatic optical system is made of two
  segmented aspheric mirrors. The primary mirror has 48 mirror panels
  with an aperture of 9.6 m, while the secondary, made of 24 panels,
  has an diameter of 5.4 m. The resulting point spread function (PSF)
  is required to be better than 4 arcmin within a field of view of 6.4
  degrees (80% of the field of view), which corresponds to a physical
  size of 6.4 mm on the focal plane. This goal represents a challenge
  for the inexpensive fabrication of aspheric mirror panels and for the
  precise alignment of the optical system as well as for the rigidity
  of the optical support structure. In this submission we introduce
  the design of the Schwarzschild-Couder optical system and describe
  the solutions adopted for the manufacturing of the mirror panels and
  their integration with the optical support structure.

Title: A Medium Sized Schwarzschild-Couder Cherenkov Telescope Design
    Proposed for the Cherenkov Telescope Array
Authors: Benbow, W.; Byrum, K.; Cameron, R.; Criswell, S.; Errando,
   M.; Guarino, V.; Humensky, B.; Kaaret, P.; Kieda, D.; Mukherjee,
   R.; Naumann, D.; Nieto, D.; Northrop, R.; Okumura, A.; Roache, E.;
   Rousselle, J.; Schlenstedt, S.; Sternberger, R.; Vassiliev, V.;
   Wakely, S.; Zhao, H. A.
Bibcode: 2015ICRC...34.1029B
Altcode: 2015PoS...236.1029B
  No abstract at ADS

Title: Characterising exoplanets and their environment with UV
    transmission spectroscopy
Authors: Fossati, L.; Bourrier, V.; Ehrenreich, D.; Haswell, C. A.;
   Kislyakova, K. G.; Lammer, H.; Lecavelier des Etangs, A.; Alibert,
   Y.; Ayres, T. R.; Ballester, G. E.; Barnes, J.; Bisikalo, D. V.;
   Collier, A.; Cameron; Czesla, S.; Desert, J. -M.; France, K.; Guedel,
   M.; Guenther, E.; Helling, Ch.; Heng, K.; Homstrom, M.; Kaltenegger,
   L.; Koskinen, T.; Lanza, A. F.; Linsky, J. L.; Mordasini, C.; Pagano,
   I.; Pollacco, D.; Rauer, H.; Reiners, A.; Salz, M.; Schneider, P. C.;
   Shematovich, V. I.; Staab, D.; Vidotto, A. A.; Wheatley, P. J.; Wood,
   B. E.; Yelle, R. V.
Bibcode: 2015arXiv150301278F
Altcode:
  Exoplanet science is now in its full expansion, particularly after
  the CoRoT and Kepler space missions that led us to the discovery of
  thousands of extra-solar planets. The last decade has taught us that
  UV observations play a major role in advancing our understanding of
  planets and of their host stars, but the necessary UV observations can
  be carried out only by HST, and this is going to be the case for many
  years to come. It is therefore crucial to build a treasury data archive
  of UV exoplanet observations formed by a dozen "golden systems" for
  which observations will be available from the UV to the infrared. Only
  in this way we will be able to fully exploit JWST observations for
  exoplanet science, one of the key JWST science case.

Title: The Solar cycle: looking forward
Authors: Cameron, Robert H.
Bibcode: 2015HiA....16..111C
Altcode:
  We discuss predictions for cycle 24 and the way forward if progress
  is to be made for cycle 25 and beyond.

Title: The crucial role of surface magnetic fields for the solar
    dynamo
Authors: Cameron, Robert; Schüssler, Manfred
Bibcode: 2015Sci...347.1333C
Altcode: 2015arXiv150308469C
  Sunspots and the plethora of other phenomena occurring in the course of
  the 11-year cycle of solar activity are a consequence of the emergence
  of magnetic flux at the solar surface. The observed orientations
  of bipolar sunspot groups imply that they originate from toroidal
  (azimuthally orientated) magnetic flux in the convective envelope
  of the Sun. We show that the net toroidal magnetic flux generated by
  differential rotation within a hemisphere of the convection zone is
  determined by the emerged magnetic flux at the solar surface and thus
  can be calculated from the observed magnetic field distribution. The
  main source of the toroidal flux is the roughly dipolar surface
  magnetic field at the polar caps, which peaks around the minima of
  the activity cycle.

Title: Simulated magnetic flows in the solar photosphere
Authors: Danilovic, S.; Cameron, R. H.; Solanki, S. K.
Bibcode: 2015A&A...574A..28D
Altcode: 2014arXiv1408.6159D
  Context. Recent Sunrise/IMaX observations have revealed supersonic
  magnetic flows. <BR /> Aims: Our aim is to determine the origin of
  these flows by using realistic magnetohydrodynamics simulations. <BR
  /> Methods: We simulated cancellation and emergence of magnetic
  flux through the solar photosphere. Our first numerical experiment
  started with a magnetic field of both polarities. To simulate
  emergence into a region with pre-existing field, we introduced a
  large-scale horizontally uniform sheet of a horizontal field. We
  followed the subsequent evolution and created synthetic polarimetric
  observations, including known instrumental effects of the Sunrise/IMaX
  and Hinode/SP instruments. We compared the simulated and observed
  spectropolarimetric signals. <BR /> Results: Strongly blue- and
  redshifted Stokes V signals are produced in locations where strong
  line-of-sight velocities coincide with the strong line-of-sight
  component of the magnetic field. The size and strength of simulated
  events is smaller than observed, and they are mostly associated with
  downflows, contrary to observations. In a few cases where they appear
  above a granule, single blue-lobed Stokes V are produced by strong
  gradients in magnetic field and velocity. No change of magnetic field
  sign is detected along the line of sight in these instances. More
  high-speed magnetised flows occurred when an emergence was simulated
  than when no horizontal field was added. <BR /> Conclusions: The
  simulations indicate that the observed events result from magnetic flux
  emergences in which reconnection may take place, but does not seem to
  be necessary. <P />The movies are available in electronic form at <A
  href="http://www.aanda.org/10.1051/0004-6361/201423779/olm">http://www.aanda.org</A>

Title: Magnetic Flux Transport at the Solar Surface
Authors: Jiang, J.; Hathaway, D. H.; Cameron, R. H.; Solanki, S. K.;
   Gizon, L.; Upton, L.
Bibcode: 2015sac..book..491J
Altcode:
  No abstract at ADS

Title: Magnetic Flux Transport at the Solar Surface
Authors: Jiang, J.; Hathaway, D. H.; Cameron, R. H.; Solanki, S. K.;
   Gizon, L.; Upton, L.
Bibcode: 2014SSRv..186..491J
Altcode: 2014SSRv..tmp...43J; 2014arXiv1408.3186J
  After emerging to the solar surface, the Sun's magnetic field displays a
  complex and intricate evolution. The evolution of the surface field is
  important for several reasons. One is that the surface field, and its
  dynamics, sets the boundary condition for the coronal and heliospheric
  magnetic fields. Another is that the surface evolution gives us insight
  into the dynamo process. In particular, it plays an essential role
  in the Babcock-Leighton model of the solar dynamo. Describing this
  evolution is the aim of the surface flux transport model. The model
  starts from the emergence of magnetic bipoles. Thereafter, the model is
  based on the induction equation and the fact that after emergence the
  magnetic field is observed to evolve as if it were purely radial. The
  induction equation then describes how the surface flows—differential
  rotation, meridional circulation, granular, supergranular flows,
  and active region inflows—determine the evolution of the field (now
  taken to be purely radial). In this paper, we review the modeling of
  the various processes that determine the evolution of the surface
  field. We restrict our attention to their role in the surface flux
  transport model. We also discuss the success of the model and some of
  the results that have been obtained using this model.

Title: ATCA follow-up of unidentified flaring Fermi gamma-ray sources
Authors: Corbel, Stephane; Edwards, Philip; Sadler, Elaine; Ojha,
   Roopesh; Thompson, David J.; Gehrels, Neil; Tingay, Steven; Cheung,
   Teddy; Wieringa, Mark; Grenier, Isabelle; Chaty, Sylvain; Dubus,
   Guillaume; Cameron, Robert; Abraham, Falcone; Schinzel, Frank
Bibcode: 2014atnf.prop.6430C
Altcode:
  This NAPA proposal will be triggered by the detection of a
  gamma-ray flare with the Large Area Telescope on the Fermi gamma-ray
  satellite. The Fermi team will identify bright sources flaring on
  day-timescales to trigger ATCA observations for southern sources for
  which no counterpart is known, which we expect to occur predominantly
  for sources with |b|&lt;1.5degrees. As Fermi source localizations
  are often better than 10arcmin, we will initially make simultaneous
  5GHz/9GHz observation, for which the primary beam is matched to the
  Fermi error region. If a radio counterpart can be identified, we will
  make follow-up observations at higher frequencies to help characterise
  the Spectral Energy Distribution of the source, and to monitor the
  evolution of the outburst at radio frequencies. History indicates
  this rapid localization and follow-up of flaring sources may well be
  critical in identifying a new class (or classes) of high energy object.

Title: Interpreting the Helioseismic and Magnetic Imager (HMI)
    Multi-Height Velocity Measurements
Authors: Nagashima, Kaori; Löptien, Björn; Gizon, Laurent; Birch,
   Aaron C.; Cameron, Robert; Couvidat, Sebastien; Danilovic, Sanja;
   Fleck, Bernhard; Stein, Robert
Bibcode: 2014SoPh..289.3457N
Altcode: 2014arXiv1404.3569N; 2014SoPh..tmp...84N
  The Solar Dynamics Observatory/Helioseismic and Magnetic Imager
  (SDO/HMI) filtergrams, taken at six wavelengths around the Fe I 6173.3
  Å line, contain information about the line-of-sight velocity over
  a range of heights in the solar atmosphere. Multi-height velocity
  inferences from these observations can be exploited to study wave
  motions and energy transport in the atmosphere. Using realistic
  convection-simulation datasets provided by the STAGGER and MURaM
  codes, we generate synthetic filtergrams and explore several methods
  for estimating Dopplergrams. We investigate at which height each
  synthetic Dopplergram correlates most strongly with the vertical
  velocity in the model atmospheres. On the basis of the investigation,
  we propose two Dopplergrams other than the standard HMI-algorithm
  Dopplergram produced from HMI filtergrams: a line-center Dopplergram
  and an average-wing Dopplergram. These two Dopplergrams correlate most
  strongly with vertical velocities at the heights of 30 - 40 km above
  (line center) and 30 - 40 km below (average wing) the effective height
  of the HMI-algorithm Dopplergram. Therefore, we can obtain velocity
  information from two layers separated by about a half of a scale height
  in the atmosphere, at best. The phase shifts between these multi-height
  Dopplergrams from observational data as well as those from the simulated
  data are also consistent with the height-difference estimates in the
  frequency range above the photospheric acoustic-cutoff frequency.

Title: The Role of Subsurface Flows in Solar Surface Convection:
    Modeling the Spectrum of Supergranular and Larger Scale Flows
Authors: Lord, J. W.; Cameron, R. H.; Rast, M. P.; Rempel, M.;
   Roudier, T.
Bibcode: 2014ApJ...793...24L
Altcode: 2014arXiv1407.2209L
  We model the solar horizontal velocity power spectrum at scales
  larger than granulation using a two-component approximation to the
  mass continuity equation. The model takes four times the density
  scale height as the integral (driving) scale of the vertical motions
  at each depth. Scales larger than this decay with height from the
  deeper layers. Those smaller are assumed to follow a Kolmogorov
  turbulent cascade, with the total power in the vertical convective
  motions matching that required to transport the solar luminosity in a
  mixing length formulation. These model components are validated using
  large-scale radiative hydrodynamic simulations. We reach two primary
  conclusions. (1) The model predicts significantly more power at low
  wavenumbers than is observed in the solar photospheric horizontal
  velocity spectrum. (2) Ionization plays a minor role in shaping the
  observed solar velocity spectrum by reducing convective amplitudes in
  the regions of partial helium ionization. The excess low wavenumber
  power is also seen in the fully nonlinear three-dimensional radiative
  hydrodynamic simulations employing a realistic equation of state. This
  adds to other recent evidence suggesting that the amplitudes of
  large-scale convective motions in the Sun are significantly lower
  than expected. Employing the same feature tracking algorithm used
  with observational data on the simulation output, we show that the
  observed low wavenumber power can be reproduced in hydrodynamic
  models if the amplitudes of large-scale modes in the deep layers
  are artificially reduced. Since the large-scale modes have reduced
  amplitudes, modes on the scale of supergranulation and smaller remain
  important to convective heat flux even in the deep layers, suggesting
  that small-scale convective correlations are maintained through the
  bulk of the solar convection zone.

Title: Effects of the Scatter in Sunspot Group Tilt Angles on the
    Large-scale Magnetic Field at the Solar Surface
Authors: Jiang, J.; Cameron, R. H.; Schüssler, M.
Bibcode: 2014ApJ...791....5J
Altcode: 2014arXiv1406.5564J
  The tilt angles of sunspot groups represent the poloidal field source
  in Babcock-Leighton-type models of the solar dynamo and are crucial for
  the build-up and reversals of the polar fields in surface flux transport
  (SFT) simulations. The evolution of the polar field is a consequence
  of Hale's polarity rules, together with the tilt angle distribution
  which has a systematic component (Joy's law) and a random component
  (tilt-angle scatter). We determine the scatter using the observed tilt
  angle data and study the effects of this scatter on the evolution of
  the solar surface field using SFT simulations with flux input based
  upon the recorded sunspot groups. The tilt angle scatter is described
  in our simulations by a random component according to the observed
  distributions for different ranges of sunspot group size (total
  umbral area). By performing simulations with a number of different
  realizations of the scatter we study the effect of the tilt angle
  scatter on the global magnetic field, especially on the evolution of
  the axial dipole moment. The average axial dipole moment at the end
  of cycle 17 (a medium-amplitude cycle) from our simulations was 2.73
  G. The tilt angle scatter leads to an uncertainty of 0.78 G (standard
  deviation). We also considered cycle 14 (a weak cycle) and cycle 19
  (a strong cycle) and show that the standard deviation of the axial
  dipole moment is similar for all three cycles. The uncertainty mainly
  results from the big sunspot groups which emerge near the equator. In
  the framework of Babcock-Leighton dynamo models, the tilt angle scatter
  therefore constitutes a significant random factor in the cycle-to-cycle
  amplitude variability, which strongly limits the predictability of
  solar activity.

Title: ATCA follow-up of unidentified flaring Fermi gamma-ray sources
Authors: Corbel, Stephane; Edwards, Philip; Sadler, Elaine; Ojha,
   Roopesh; Thompson, David J.; Gehrels, Neil; Tingay, Steven; Cheung,
   Teddy; Wieringa, Mark; Grenier, Isabelle; Chaty, Sylvain; Dubus,
   Guillaume; Cameron, Robert; Abraham, Falcone; Schinzel, Frank
Bibcode: 2014atnf.prop.6049C
Altcode:
  This NAPA proposal will be triggered by the detection of a
  gamma-ray flare with the Large Area Telescope on the Fermi gamma-ray
  satellite. The Fermi team will identify bright sources flaring on
  day-timescales to trigger ATCA observations for southern sources for
  which no counterpart is known, which we expect to occur predominantly
  for sources with |b|&lt;1.5degrees. As Fermi source localizations
  are often better than 10arcmin, we will initially make simultaneous
  5GHz/9GHz observation, for which the primary beam is matched to the
  Fermi error region. If a radio counterpart can be identified, we will
  make follow-up observations at higher frequencies to help characterise
  the Spectral Energy Distribution of the source, and to monitor the
  evolution of the outburst at radio frequencies. History indicates
  this rapid localization and follow-up of flaring sources may well be
  critical in identifying a new class (or classes) of high energy object.

Title: Migration of Ca II H bright points in the internetwork
Authors: Jafarzadeh, S.; Cameron, R. H.; Solanki, S. K.; Pietarila,
   A.; Feller, A.; Lagg, A.; Gandorfer, A.
Bibcode: 2014A&A...563A.101J
Altcode: 2014arXiv1401.7522J
  Context. The migration of magnetic bright point-like features (MBP)
  in the lower solar atmosphere reflects the dispersal of magnetic
  flux as well as the horizontal flows of the atmospheric layer they
  are embedded in. <BR /> Aims: We analyse trajectories of the proper
  motion of intrinsically magnetic, isolated internetwork Ca ii H MBPs
  (mean lifetime 461 ± 9 s) to obtain their diffusivity behaviour. <BR
  /> Methods: We use seeing-free high spatial and temporal resolution
  image sequences of quiet-Sun, disc-centre observations obtained in
  the Ca ii H 3968 Å passband of the Sunrise Filter Imager (SuFI)
  onboard the Sunrise balloon-borne solar observatory. Small MBPs in
  the internetwork are automatically tracked. The trajectory of each
  MBP is then calculated and described by a diffusion index (γ) and
  a diffusion coefficient (D). We also explore the distribution of the
  diffusion indices with the help of a Monte Carlo simulation. <BR />
  Results: We find γ = 1.69 ± 0.08 and D = 257 ± 32 km<SUP>2</SUP>
  s<SUP>-1</SUP> averaged over all MBPs. Trajectories of most MBPs are
  classified as super-diffusive, i.e. γ &gt; 1, with the determined γ
  being the largest obtained so far to our knowledge. A direct correlation
  between D and timescale (τ) determined from trajectories of all MBPs is
  also obtained. We discuss a simple scenario to explain the diffusivity
  of the observed, relatively short-lived MBPs while they migrate within
  a small area in a supergranule (i.e. an internetwork area). We show
  that the scatter in the γ values obtained for individual MBPs is due
  to their limited lifetimes. <BR /> Conclusions: The super-diffusive
  MBPs can be described as random walkers (due to granular evolution and
  intergranular turbulence) superposed on a large systematic (background)
  velocity, caused by granular, mesogranular, and supergranular flows.

Title: Physical causes of solar cycle amplitude variability
Authors: Cameron, R. H.; Jiang, J.; Schüssler, M.; Gizon, L.
Bibcode: 2014JGRA..119..680C
Altcode:
  The level of solar activity varies from cycle to cycle. This
  variability is probably caused by a combination of nonlinear and
  random effects. Based on surface flux transport simulations, we
  show that the observed inflows into active regions and toward the
  activity belts provide an important nonlinearity in the framework of
  Babcock-Leighton model for the solar dynamo. Inclusion of these inflows
  also leads to a reproduction of the observed proportionality between
  the open heliospheric flux during activity minima and the maximum
  sunspot number of the following cycle. A substantial component of
  the random variability of the cycle strength is associated with the
  cross-equatorial flux plumes that occur when large, highly tilted
  sunspot groups emerge close to the equator. We show that the flux
  transported by these events is important for the amplitude of the polar
  fields and open flux during activity minima. The combined action of
  inflows and cross-equatorial flux plumes provides an explanation for
  the weakness of the polar fields at the end of solar cycle 23 (and
  hence for the relative weakness of solar cycle 24).

Title: Can Surface Flux Transport Account for the Weak Polar Field
    in Cycle 23?
Authors: Jiang, Jie; Cameron, Robert H.; Schmitt, Dieter; Schüssler,
   Manfred
Bibcode: 2014crh..book..289J
Altcode:
  No abstract at ADS

Title: Snowmass Cosmic Frontiers 6 (CF6) Working Group Summary --The
Bright Side of the Cosmic Frontier: Cosmic Probes of Fundamental
    Physics
Authors: Beatty, J. J.; Nelson, A. E.; Olinto, A.; Sinnis, G.;
   Abeysekara, A. U.; Anchordoqui, L. A.; Aramaki, T.; Belz, J.; Buckley,
   J. H.; Byrum, K.; Cameron, R.; Chen, M-C.; Clark, K.; Connolly, A.;
   Cowen, D.; DeYoung, T.; Dumm, P. von Doetinchem J.; Errando, M.;
   Farrar, G.; Ferrer, F.; Fortson, L.; Funk, S.; Grant, D.; Griffiths,
   S.; Groß, A.; Hailey, C.; Hogan, C.; Holder, J.; Humensky, B.;
   Kaaret, P.; Klein, S. R.; Krawczynski, H.; Krennrich, F.; Krings,
   K.; Krizmanic, J.; Kusenko, A.; Linnemann, J. T.; MacGibbon, J. H.;
   Matthews, J.; McCann, A.; Mitchell, J.; Mukherjee, R.; Nitz, D.;
   Ong, R. A.; Orr, M.; Otte, N.; Paul, T.; Resconi, E.; Sanchez-Conde,
   M. A.; Sokolsky, P.; Stecker, F.; Stump, D.; Taboada, I.; Thomson,
   G. B.; Tollefson, K.; von Doetinchem, P.; Ukwatta, T.; Vandenbroucke,
   J.; Vasileiou, V.; Vassileiv, V. V.; Weiler, T. J.; Williams, D. A.;
   Weinstein, A.; Wood, M.; Zitzer, B.
Bibcode: 2013arXiv1310.5662B
Altcode:
  Report of the CF6 Working Group at Snowmass 2013. Topics addressed
  include ultra-high energy cosmic rays, neutrinos, gamma rays,
  baryogenesis, and experiments probing the fundamental nature of
  spacetime.

Title: Three-dimensional simulations of near-surface convection in
    main-sequence stars. II. Properties of granulation and spectral lines
Authors: Beeck, B.; Cameron, R. H.; Reiners, A.; Schüssler, M.
Bibcode: 2013A&A...558A..49B
Altcode: 2013arXiv1308.4873B
  Context. The atmospheres of cool main-sequence stars are structured
  by convective flows from the convective envelope that penetrate the
  optically thin layers and lead to structuring of the stellar atmospheres
  analogous to solar granulation. The flows have considerable influence on
  the 3D structure of temperature and pressure and affect the profiles
  of spectral lines formed in the photosphere. <BR /> Aims: For the
  set of six 3D radiative (M)HD simulations of cool main-sequence
  stars described in the first paper of this series, we analyse the
  near-surface layers. We aim at describing the properties of granulation
  of different stars and at quantifying the effects on spectral lines of
  the thermodynamic structure and flows of 3D convective atmospheres. <BR
  /> Methods: We detected and tracked granules in brightness images
  from the simulations to analyse their statistical properties, as well
  as their evolution and lifetime. We calculated spatially resolved
  spectral line profiles using the line synthesis code SPINOR. To enable
  a comparison to stellar observations, we implemented a numerical
  disc-integration, which includes (differential) rotation. <BR />
  Results: Although the stellar parameters change considerably along the
  model sequence, the properties of the granules are very similar. The
  impact of the 3D structure of the atmospheres on line profiles is
  measurable in disc-integrated spectra. Line asymmetries caused by
  convection are modulated by stellar rotation. <BR /> Conclusions:
  The 3D structure of cool stellar atmospheres as shaped by convective
  flows has to be taken into account when using photospheric lines to
  determine stellar parameters.

Title: Polar plumes' orientation and the Sun's global magnetic field
Authors: de Patoul, Judith; Inhester, Bernd; Cameron, Robert
Bibcode: 2013A&A...558L...4D
Altcode: 2013arXiv1309.5916D
  <BR /> Aims: We characterize the orientation of polar plumes as a
  tracer of the large-scale coronal magnetic field configuration. We
  monitor in particular the north and south magnetic pole locations and
  the magnetic opening during 2007-2008 and provide some understanding
  of the variations in these quantities. <BR /> Methods: The polar plume
  orientation is determined by applying the Hough-wavelet transform to
  a series of EUV images and extracting the key Hough space parameters
  of the resulting maps. The same procedure is applied to the polar cap
  field inclination derived from extrapolating magnetograms generated
  by a surface flux transport model. <BR /> Results: We observe that
  the position where the magnetic field is radial (the Sun's magnetic
  poles) reflects the global organization of magnetic field on the
  solar surface, and we suggest that this opens the possibility of both
  detecting flux emergence anywhere on the solar surface (including the
  far side) and better constraining the reorganization of the corona
  after flux emergence.

Title: Three-dimensional simulations of near-surface convection in
    main-sequence stars. I. Overall structure
Authors: Beeck, B.; Cameron, R. H.; Reiners, A.; Schüssler, M.
Bibcode: 2013A&A...558A..48B
Altcode: 2013arXiv1308.4874B
  Context. The near-surface layers of cool main-sequence stars are
  structured by convective flows, which are overshooting into the
  atmosphere. The flows and the associated spatio-temporal variations of
  density and temperature affect spectral line profiles and thus have an
  impact on estimates of stellar properties such as effective temperature,
  gravitational acceleration, and abundances. <BR /> Aims: We aim at
  identifying distinctive properties of the thermodynamic structure of
  the atmospheres of different stars and understand their causes. <BR />
  Methods: We ran comprehensive 3D radiation hydrodynamics simulations
  of the near-surface layers of six simulated stars of spectral type
  F3V to M2V with the MURaM code. We carry out a systematic parameter
  study of the mean stratifications, flow structures, and the energy
  flux in these stars. <BR /> Results: We find monotonic trends along
  the lower main sequence in granule size, flow velocity, and intensity
  contrast. The convection in the M-star models differs substantially
  from that of the hotter stars, mainly owing to the more gradual
  transition from convective to radiative energy transport. <BR />
  Conclusions: While the basic mechanisms driving surface convection
  in cool stars are the same, the properties of the convection vary
  along the main sequence. Apart from monotonic trends in rms velocity,
  intensity contrast, granule size, etc., there is a transition between
  "naked" and "hidden" granulation around spectral type K5V caused by
  the (highly non-linear) temperature dependence of the opacity. These
  variations have to be taken into account when stellar parameters are
  derived from spectra. <P />Appendix A is available in electronic form
  at <A href="http://www.aanda.org">http://www.aanda.org</A>

Title: Helioseismology of sunspots: how sensitive are travel times
    to the Wilson depression and to the subsurface magnetic field?
Authors: Schunker, H.; Gizon, L.; Cameron, R. H.; Birch, A. C.
Bibcode: 2013A&A...558A.130S
Altcode: 2013arXiv1303.6307S
  To assess the ability of helioseismology to probe the subsurface
  structure and magnetic field of sunspots, we need to determine
  how helioseismic travel times depend on perturbations to
  sunspot models. Here we numerically simulate the propagation of f,
  p<SUB>1</SUB>, and p<SUB>2</SUB> wave packets through magnetic sunspot
  models. Among the models we considered, a ±50 km change in the height
  of the Wilson depression and a change in the subsurface magnetic
  field geometry can both be detected above the observational noise
  level. We also find that the travel-time shifts due to changes in a
  sunspot model must be modeled by computing the effects of changing the
  reference sunspot model, and not by computing the effects of changing
  the subsurface structure in the quiet-Sun model. For p<SUB>1</SUB>
  modes, the latter is wrong by a factor of four. In conclusion, numerical
  modeling of MHD wave propagation is an essential tool for interpreting
  the effects of sunspots on seismic waveforms.

Title: ATCA follow-up of unidentified flaring Fermi gamma-ray sources
Authors: Corbel, Stephane; Edwards, Philip; Sadler, Elaine; Ojha,
   Roopesh; Thompson, David J.; Gehrels, Neil; Tingay, Steven; Cheung,
   Teddy; Wieringa, Mark; Grenier, Isabelle; Chaty, Sylvain; Dubus,
   Guillaume; Cameron, Robert; Abraham, Falcone; Schinzel, Frank
Bibcode: 2013atnf.prop.5777C
Altcode:
  This NAPA proposal will be triggered by the detection of a
  gamma-ray flare with the Large Area Telescope on the Fermi gamma-ray
  satellite. The Fermi team will identify bright sources flaring on
  day-timescales to trigger ATCA observations for southern sources for
  which no counterpart is known, which we expect to occur predominantly
  for sources with |b|&lt;1.5degrees. As Fermi source localizations
  are often better than 10arcmin, we will initially make simultaneous
  5GHz/9GHz observation, for which the primary beam is matched to the
  Fermi error region. If a radio counterpart can be identified, we will
  make follow-up observations at higher frequencies to help characterise
  the Spectral Energy Distribution of the source, and to monitor the
  evolution of the outburst at radio frequencies. History indicates
  this rapid localization and follow-up of flaring sources may well be
  critical in identifying a new class (or classes) of high energy object.

Title: Limits to solar cycle predictability: Cross-equatorial
    flux plumes
Authors: Cameron, R. H.; Dasi-Espuig, M.; Jiang, J.; Işık, E.;
   Schmitt, D.; Schüssler, M.
Bibcode: 2013A&A...557A.141C
Altcode: 2013arXiv1308.2827C
  Context. Within the Babcock-Leighton framework for the solar dynamo, the
  strength of a cycle is expected to depend on the strength of the dipole
  moment or net hemispheric flux during the preceding minimum, which
  depends on how much flux was present in each hemisphere at the start of
  the previous cycle and how much net magnetic flux was transported across
  the equator during the cycle. Some of this transport is associated
  with the random walk of magnetic flux tubes subject to granular and
  supergranular buffeting, some of it is due to the advection caused by
  systematic cross-equatorial flows such as those associated with the
  inflows into active regions, and some crosses the equator during the
  emergence process. <BR /> Aims: We aim to determine how much of the
  cross-equatorial transport is due to small-scale disorganized motions
  (treated as diffusion) compared with other processes such as emergence
  flux across the equator. <BR /> Methods: We measure the cross-equatorial
  flux transport using Kitt Peak synoptic magnetograms, estimating both
  the total and diffusive fluxes. <BR /> Results: Occasionally a large
  sunspot group, with a large tilt angle emerges crossing the equator,
  with flux from the two polarities in opposite hemispheres. The largest
  of these events carry a substantial amount of flux across the equator
  (compared to the magnetic flux near the poles). We call such events
  cross-equatorial flux plumes. There are very few such large events
  during a cycle, which introduces an uncertainty into the determination
  of the amount of magnetic flux transported across the equator in any
  particular cycle. As the amount of flux which crosses the equator
  determines the amount of net flux in each hemisphere, it follows that
  the cross-equatorial plumes introduce an uncertainty in the prediction
  of the net flux in each hemisphere. This leads to an uncertainty in
  predictions of the strength of the following cycle.

Title: No evidence for planetary influence on solar activity
Authors: Cameron, R. H.; Schüssler, M.
Bibcode: 2013A&A...557A..83C
Altcode: 2013arXiv1307.5988C
  Context. Recently, Abreu et al. (2012, A&amp;A. 548, A88) proposed
  a long-term modulation of solar activity through tidal effects
  exerted by the planets. This claim is based upon a comparison of
  (pseudo-)periodicities derived from records of cosmogenic isotopes
  with those arising from planetary torques on an ellipsoidally deformed
  Sun. <BR /> Aims: We examined the statistical significance of the
  reported similarity of the periods. <BR /> Methods: The tests carried
  out by Abreu et al. were repeated with artificial records of solar
  activity in the form of white or red noise. The tests were corrected
  for errors in the noise definition as well as in the apodisation and
  filtering of the random series. <BR /> Results: The corrected tests
  provide probabilities for chance coincidence that are higher than
  those claimed by Abreu et al. by about 3 and 8 orders of magnitude
  for white and red noise, respectively. For an unbiased choice of the
  width of the frequency bins used for the test (a constant multiple of
  the frequency resolution) the probabilities increase by another two
  orders of magnitude to 7.5% for red noise and 22% for white noise. <BR
  /> Conclusions: The apparent agreement between the periodicities
  in records of cosmogenic isotopes as proxies for solar activity and
  planetary torques is statistically insignificant. There is no evidence
  for a planetary influence on solar activity.

Title: Sunspot group tilt angles and the strength of the solar cycle
    (Corrigendum)
Authors: Dasi-Espuig, M.; Solanki, S. K.; Krivova, N. A.; Cameron,
   R.; Peñuela, T.
Bibcode: 2013A&A...556C...3D
Altcode:
  No abstract at ADS

Title: CTA contributions to the 33rd International Cosmic Ray
    Conference (ICRC2013)
Authors: CTA Consortium, The; :; Abril, O.; Acharya, B. S.; Actis, M.;
   Agnetta, G.; Aguilar, J. A.; Aharonian, F.; Ajello, M.; Akhperjanian,
   A.; Alcubierre, M.; Aleksic, J.; Alfaro, R.; Aliu, E.; Allafort,
   A. J.; Allan, D.; Allekotte, I.; Aloisio, R.; Amato, E.; Ambrosi,
   G.; Ambrosio, M.; Anderson, J.; Angüner, E. O.; Antonelli, L. A.;
   Antonuccio, V.; Antonucci, M.; Antoranz, P.; Aravantinos, A.; Argan,
   A.; Arlen, T.; Aramo, C.; Armstrong, T.; Arnaldi, H.; Arrabito, L.;
   Asano, K.; Ashton, T.; Asorey, H. G.; Aune, T.; Awane, Y.; Baba, H.;
   Babic, A.; Baby, N.; Bähr, J.; Bais, A.; Baixeras, C.; Bajtlik, S.;
   Balbo, M.; Balis, D.; Balkowski, C.; Ballet, J.; Bamba, A.; Bandiera,
   R.; Barber, A.; Barbier, C.; Barceló, M.; Barnacka, A.; Barnstedt,
   J.; Barres de Almeida, U.; Barrio, J. A.; Basili, A.; Basso, S.;
   Bastieri, D.; Bauer, C.; Baushev, A.; Becciani, U.; Becerra, J.;
   Becerra, J.; Becherini, Y.; Bechtol, K. C.; Becker Tjus, J.; Beckmann,
   V.; Bednarek, W.; Behera, B.; Belluso, M.; Benbow, W.; Berdugo, J.;
   Berge, D.; Berger, K.; Bernard, F.; Bernardino, T.; Bernlöhr, K.;
   Bertucci, B.; Bhat, N.; Bhattacharyya, S.; Biasuzzi, B.; Bigongiari,
   C.; Biland, A.; Billotta, S.; Bird, T.; Birsin, E.; Bissaldi, E.;
   Biteau, J.; Bitossi, M.; Blake, S.; Blanch Bigas, O.; Blasi, P.;
   Bobkov, A.; Boccone, V.; Böttcher, M.; Bogacz, L.; Bogart, J.;
   Bogdan, M.; Boisson, C.; Boix Gargallo, J.; Bolmont, J.; Bonanno,
   G.; Bonardi, A.; Bonev, T.; Bonifacio, P.; Bonnoli, G.; Bordas,
   P.; Borgland, A.; Borkowski, J.; Bose, R.; Botner, O.; Bottani, A.;
   Bouchet, L.; Bourgeat, M.; Boutonnet, C.; Bouvier, A.; Brau-Nogué, S.;
   Braun, I.; Bretz, T.; Briggs, M.; Brigida, M.; Bringmann, T.; Britto,
   R.; Brook, P.; Brun, P.; Brunetti, L.; Bruno, P.; Bucciantini, N.;
   Buanes, T.; Buckley, J.; Bühler, R.; Bugaev, V.; Bulgarelli, A.;
   Bulik, T.; Busetto, G.; Buson, S.; Byrum, K.; Cailles, M.; Cameron,
   R.; Camprecios, J.; Canestrari, R.; Cantu, S.; Capalbi, M.; Caraveo,
   P.; Carmona, E.; Carosi, A.; Carosi, R.; Carr, J.; Carter, J.;
   Carton, P. -H.; Caruso, R.; Casanova, S.; Cascone, E.; Casiraghi, M.;
   Castellina, A.; Catalano, O.; Cavazzani, S.; Cazaux, S.; Cerchiara,
   P.; Cerruti, M.; Chabanne, E.; Chadwick, P.; Champion, C.; Chaves,
   R.; Cheimets, P.; Chen, A.; Chiang, J.; Chiappetti, L.; Chikawa, M.;
   Chitnis, V. R.; Chollet, F.; Christof, A.; Chudoba, J.; Cieślar, M.;
   Cillis, A.; Cilmo, M.; Codino, A.; Cohen-Tanugi, J.; Colafrancesco,
   S.; Colin, P.; Colome, J.; Colonges, S.; Compin, M.; Conconi, P.;
   Conforti, V.; Connaughton, V.; Conrad, J.; Contreras, J. L.; Coppi,
   P.; Coridian, J.; Corona, P.; Corti, D.; Cortina, J.; Cossio, L.;
   Costa, A.; Costantini, H.; Cotter, G.; Courty, B.; Couturier, S.;
   Covino, S.; Crimi, G.; Criswell, S. J.; Croston, J.; Cusumano, G.;
   Dafonseca, M.; Dale, O.; Daniel, M.; Darling, J.; Davids, I.; Dazzi,
   F.; de Angelis, A.; De Caprio, V.; De Frondat, F.; de Gouveia Dal Pino,
   E. M.; de la Calle, I.; De La Vega, G. A.; de los Reyes Lopez, R.;
   de Lotto, B.; De Luca, A.; de Naurois, M.; de Oliveira, Y.; de Oña
   Wilhelmi, E.; de Palma, F.; de Souza, V.; Decerprit, G.; Decock, G.;
   Deil, C.; Delagnes, E.; Deleglise, G.; Delgado, C.; della Volpe, D.;
   Demange, P.; Depaola, G.; Dettlaff, A.; Di Girolamo, T.; Di Giulio,
   C.; Di Paola, A.; Di Pierro, F.; di Sciascio, G.; Díaz, C.; Dick, J.;
   Dickherber, R.; Dickinson, H.; Diez-Blanco, V.; Digel, S.; Dimitrov,
   D.; Disset, G.; Djannati-Ataï, A.; Doert, M.; Dohmke, M.; Domainko,
   W.; Dominis Prester, D.; Donat, A.; Dorner, D.; Doro, M.; Dournaux,
   J. -L.; Drake, G.; Dravins, D.; Drury, L.; Dubois, F.; Dubois, R.;
   Dubus, G.; Dufour, C.; Dumas, D.; Dumm, J.; Durand, D.; Dwarkadas, V.;
   Dyks, J.; Dyrda, M.; Ebr, J.; Edy, E.; Egberts, K.; Eger, P.; Einecke,
   S.; Eleftheriadis, C.; Elles, S.; Emmanoulopoulos, D.; Engelhaupt,
   D.; Enomoto, R.; Ernenwein, J. -P.; Errando, M.; Etchegoyen, A.;
   Evans, P. A.; Falcone, A.; Faltenbacher, A.; Fantinel, D.; Farakos,
   K.; Farnier, C.; Farrell, E.; Fasola, G.; Favill, B. W.; Fede,
   E.; Federici, S.; Fegan, S.; Feinstein, F.; Ferenc, D.; Ferrando,
   P.; Fesquet, M.; Fetfatzis, P.; Fiasson, A.; Fillin-Martino, E.;
   Fink, D.; Finley, C.; Finley, J. P.; Fiorini, M.; Firpo Curcoll,
   R.; Flandrini, E.; Fleischhack, H.; Flores, H.; Florin, D.; Focke,
   W.; Föhr, C.; Fokitis, E.; Font, L.; Fontaine, G.; Fornasa, M.;
   Förster, A.; Fortson, L.; Fouque, N.; Franckowiak, A.; Franco, F. J.;
   Frankowski, A.; Fransson, C.; Fraser, G. W.; Frei, R.; Fresnillo, L.;
   Fruck, C.; Fugazza, D.; Fujita, Y.; Fukazawa, Y.; Fukui, Y.; Funk,
   S.; Gäbele, W.; Gabici, S.; Gabriele, R.; Gadola, A.; Galante, N.;
   Gall, D.; Gallant, Y.; Gámez-García, J.; Garczarczyk, M.; García,
   B.; Garcia López, R.; Gardiol, D.; Gargano, F.; Garrido, D.; Garrido,
   L.; Gascon, D.; Gaug, M.; Gaweda, J.; Gebremedhin, L.; Geffroy, N.;
   Gerard, L.; Ghedina, A.; Ghigo, M.; Ghislain, P.; Giannakaki, E.;
   Gianotti, F.; Giarrusso, S.; Giavitto, G.; Giebels, B.; Giglietto,
   N.; Gika, V.; Giomi, M.; Giommi, P.; Giordano, F.; Girard, N.; Giro,
   E.; Giuliani, A.; Glanzman, T.; Glicenstein, J. -F.; Godinovic, N.;
   Golev, V.; Gomez Berisso, M.; Gómez-Ortega, J.; Gonzalez, M. M.;
   González, A.; González, F.; González Muñoz, A.; Gothe, K. S.;
   Grabarczyk, T.; Gougerot, M.; Graciani, R.; Grandi, P.; Grañena,
   F.; Granot, J.; Grasseau, G.; Gredig, R.; Green, A.; Greenshaw, T.;
   Grégoire, T.; Grillo, A.; Grimm, O.; Grondin, M. -H.; Grube, J.;
   Grudzinska, M.; Gruev, V.; Grünewald, S.; Grygorczuk, J.; Guarino,
   V.; Gunji, S.; Gyuk, G.; Hadasch, D.; Hagedorn, A.; Hagiwara, R.;
   Hahn, J.; Hakansson, N.; Hallgren, A.; Hamer Heras, N.; Hara, S.;
   Hardcastle, M. J.; Harezlak, D.; Harris, J.; Hassan, T.; Hatanaka,
   K.; Haubold, T.; Haupt, A.; Hayakawa, T.; Hayashida, M.; Heller, R.;
   Henault, F.; Henri, G.; Hermann, G.; Hermel, R.; Herrero, A.; Hervet,
   O.; Hidaka, N.; Hinton, J. A.; Hirotani, K.; Hoffmann, D.; Hofmann,
   W.; Hofverberg, P.; Holder, J.; Hörandel, J. R.; Horns, D.; Horville,
   D.; Houles, J.; Hrabovsky, M.; Hrupec, D.; Huan, H.; Huber, B.; Huet,
   J. -M.; Hughes, G.; Humensky, T. B.; Huovelin, J.; Huppert, J. -F.;
   Ibarra, A.; Ikawa, D.; Illa, J. M.; Impiombato, D.; Incorvaia, S.;
   Inoue, S.; Inoue, Y.; Iocco, F.; Ioka, K.; Israel, G. L.; Jablonski,
   C.; Jacholkowska, A.; Jacquemier, J.; Jamrozy, M.; Janiak, M.; Jean,
   P.; Jeanney, C.; Jimenez, J. J.; Jogler, T.; Johnson, C.; Johnson,
   T.; Journet, L.; Juffroy, C.; Jung, I.; Kaaret, P.; Kabuki, S.;
   Kagaya, M.; Kakuwa, J.; Kalkuhl, C.; Kankanyan, R.; Karastergiou,
   A.; Kärcher, K.; Karczewski, M.; Karkar, S.; Kasperek, J.; Kastana,
   D.; Katagiri, H.; Kataoka, J.; Katarzyński, K.; Katz, U.; Kawanaka,
   N.; Kazanas, D.; Kelley-Hoskins, N.; Kellner-Leidel, B.; Kelly, H.;
   Kendziorra, E.; Khélifi, B.; Kieda, D. B.; Kifune, T.; Kihm, T.;
   Kishimoto, T.; Kitamoto, K.; Kluźniak, W.; Knapic, C.; Knapp, J.;
   Knödlseder, J.; Köck, F.; Kocot, J.; Kodani, K.; Köhne, J. -H.;
   Kohri, K.; Kokkotas, K.; Kolitzus, D.; Komin, N.; Kominis, I.; Konno,
   Y.; Köppel, H.; Korohoda, P.; Kosack, K.; Koss, G.; Kossakowski,
   R.; Koul, R.; Kowal, G.; Koyama, S.; Kozioł, J.; Krähenbühl, T.;
   Krause, J.; Krawzcynski, H.; Krennrich, F.; Krepps, A.; Kretzschmann,
   A.; Krobot, R.; Krueger, P.; Kubo, H.; Kudryavtsev, V. A.; Kushida,
   J.; Kuznetsov, A.; La Barbera, A.; La Palombara, N.; La Parola, V.;
   La Rosa, G.; Lacombe, K.; Lamanna, G.; Lande, J.; Languignon, D.;
   Lapington, J. S.; Laporte, P.; Laurent, B.; Lavalley, C.; Le Flour,
   T.; Le Padellec, A.; Lee, S. -H.; Lee, W. H.; Lefèvre, J. -P.; Leich,
   H.; Leigui de Oliveira, M. A.; Lelas, D.; Lenain, J. -P.; Leoni,
   R.; Leopold, D. J.; Lerch, T.; Lessio, L.; Leto, G.; Lieunard, B.;
   Lieunard, S.; Lindemann, R.; Lindfors, E.; Liolios, A.; Lipniacka,
   A.; Lockart, H.; Lohse, T.; Lombardi, S.; Longo, F.; Lopatin, A.;
   Lopez, M.; López-Coto, R.; López-Oramas, A.; Lorca, A.; Lorenz,
   E.; Louis, F.; Lubinski, P.; Lucarelli, F.; Lüdecke, H.; Ludwin, J.;
   Luque-Escamilla, P. L.; Lustermann, W.; Luz, O.; Lyard, E.; Maccarone,
   M. C.; Maccarone, T. J.; Madejski, G. M.; Madhavan, A.; Mahabir, M.;
   Maier, G.; Majumdar, P.; Malaguti, G.; Malaspina, G.; Maltezos, S.;
   Manalaysay, A.; Mancilla, A.; Mandat, D.; Maneva, G.; Mangano, A.;
   Manigot, P.; Mannheim, K.; Manthos, I.; Maragos, N.; Marcowith, A.;
   Mariotti, M.; Marisaldi, M.; Markoff, S.; Marszałek, A.; Martens,
   C.; Martí, J.; Martin, J. -M.; Martin, P.; Martínez, G.; Martínez,
   F.; Martínez, M.; Massaro, F.; Masserot, A.; Mastichiadis, A.;
   Mathieu, A.; Matsumoto, H.; Mattana, F.; Mattiazzo, S.; Maurer, A.;
   Maurin, G.; Maxfield, S.; Maya, J.; Mazin, D.; Mc Comb, L.; McCann,
   A.; McCubbin, N.; McHardy, I.; McKay, R.; Meagher, K.; Medina, C.;
   Melioli, C.; Melkumyan, D.; Melo, D.; Mereghetti, S.; Mertsch, P.;
   Meucci, M.; Meyer, M.; Michałowski, J.; Micolon, P.; Mihailidis,
   A.; Mineo, T.; Minuti, M.; Mirabal, N.; Mirabel, F.; Miranda, J. M.;
   Mirzoyan, R.; Mistò, A.; Mizuno, T.; Moal, B.; Moderski, R.; Mognet,
   I.; Molinari, E.; Molinaro, M.; Montaruli, T.; Monte, C.; Monteiro, I.;
   Moore, P.; Moralejo Olaizola, A.; Mordalska, M.; Morello, C.; Mori,
   K.; Morlino, G.; Morselli, A.; Mottez, F.; Moudden, Y.; Moulin, E.;
   Mrusek, I.; Mukherjee, R.; Munar-Adrover, P.; Muraishi, H.; Murase, K.;
   StJ. Murphy, A.; Nagataki, S.; Naito, T.; Nakajima, D.; Nakamori, T.;
   Nakayama, K.; Naumann, C.; Naumann, D.; Naumann-Godo, M.; Nayman, P.;
   Nedbal, D.; Neise, D.; Nellen, L.; Neronov, A.; Neustroev, V.; Neyroud,
   N.; Nicastro, L.; Nicolau-Kukliński, J.; Niedźwiecki, A.; Niemiec,
   J.; Nieto, D.; Nikolaidis, A.; Nishijima, K.; Nishikawa, K. -I.;
   Noda, K.; Nolan, S.; Northrop, R.; Nosek, D.; Nowak, N.; Nozato, A.;
   Oakes, L.; O'Brien, P. T.; Ohira, Y.; Ohishi, M.; Ohm, S.; Ohoka, H.;
   Okuda, T.; Okumura, A.; Olive, J. -F.; Ong, R. A.; Orito, R.; Orr, M.;
   Osborne, J. P.; Ostrowski, M.; Otero, L. A.; Otte, N.; Ovcharov, E.;
   Oya, I.; Ozieblo, A.; Padilla, L.; Pagano, I.; Paiano, S.; Paillot, D.;
   Paizis, A.; Palanque, S.; Palatka, M.; Pallota, J.; Palatiello, M.;
   Panagiotidis, K.; Panazol, J. -L.; Paneque, D.; Panter, M.; Panzera,
   M. R.; Paoletti, R.; Papayannis, A.; Papyan, G.; Paredes, J. M.;
   Pareschi, G.; Parraud, J. -M.; Parsons, D.; Pauletta, G.; Paz Arribas,
   M.; Pech, M.; Pedaletti, G.; Pelassa, V.; Pelat, D.; Perez, M. d. C.;
   Persic, M.; Petrucci, P. -O.; Peyaud, B.; Pichel, A.; Pieloth, D.;
   Pierre, E.; Pita, S.; Pivato, G.; Pizzolato, F.; Platino, M.; Platos,
   Ł.; Platzer, R.; Podkladkin, S.; Pogosyan, L.; Pohl, M.; Pojmanski,
   G.; Ponz, J. D.; Potter, W.; Poutanen, J.; Prandini, E.; Prast,
   J.; Preece, R.; Profeti, F.; Prokoph, H.; Prouza, M.; Proyetti, M.;
   Puerto-Giménez, I.; Pühlhofer, G.; Puljak, I.; Punch, M.; Pyzioł,
   R.; Quel, E. J.; Quesada, J.; Quinn, J.; Quirrenbach, A.; Racero, E.;
   Rainò, S.; Rajda, P. J.; Rameez, M.; Ramon, P.; Rando, R.; Rannot,
   R. C.; Rataj, M.; Raue, M.; Ravignani, D.; Reardon, P.; Reimann,
   O.; Reimer, A.; Reimer, O.; Reitberger, K.; Renaud, M.; Renner,
   S.; Reville, B.; Rhode, W.; Ribó, M.; Ribordy, M.; Richards, G.;
   Richer, M. G.; Rico, J.; Ridky, J.; Rieger, F.; Ringegni, P.; Ripken,
   J.; Ristori, P. R.; Rivière, A.; Rivoire, S.; Rob, L.; Rodeghiero,
   G.; Roeser, U.; Rohlfs, R.; Rojas, G.; Romano, P.; Romaszkan, W.;
   Romero, G. E.; Rosen, S. R.; Rosier Lees, S.; Ross, D.; Rouaix, G.;
   Rousselle, J.; Rousselle, S.; Rovero, A. C.; Roy, F.; Royer, S.;
   Rudak, B.; Rulten, C.; Rupiński, M.; Russo, F.; Ryde, F.; Saavedra,
   O.; Sacco, B.; Saemann, E. O.; Saggion, A.; Sahakian, V.; Saito, K.;
   Saito, T.; Saito, Y.; Sakaki, N.; Sakonaka, R.; Salini, A.; Sanchez,
   F.; Sanchez-Conde, M.; Sandoval, A.; Sandaker, H.; Sant'Ambrogio, E.;
   Santangelo, A.; Santos, E. M.; Sanuy, A.; Sapozhnikov, L.; Sarkar,
   S.; Sartore, N.; Sasaki, H.; Satalecka, K.; Sawada, M.; Scalzotto, V.;
   Scapin, V.; Scarcioffolo, M.; Schafer, J.; Schanz, T.; Schlenstedt,
   S.; Schlickeiser, R.; Schmidt, T.; Schmoll, J.; Schovanek, P.;
   Schroedter, M.; Schubert, A.; Schultz, C.; Schultze, J.; Schulz,
   A.; Schure, K.; Schussler, F.; Schwab, T.; Schwanke, U.; Schwarz,
   J.; Schwarzburg, S.; Schweizer, T.; Schwemmer, S.; Schwendicke, U.;
   Schwerdt, C.; Segreto, A.; Seiradakis, J. -H.; Sembroski, G. H.;
   Servillat, M.; Seweryn, K.; Sharma, M.; Shayduk, M.; Shellard,
   R. C.; Shi, J.; Shibata, T.; Shibuya, A.; Shore, S.; Shum, E.;
   Sideras-Haddad, E.; Sidoli, L.; Sidz, M.; Sieiro, J.; Sikora, M.;
   Silk, J.; Sillanpää, A.; Singh, B. B.; Sironi, G.; Sitarek, J.;
   Skole, C.; Smareglia, R.; Smith, A.; Smith, D.; Smith, J.; Smith,
   N.; Sobczyńska, D.; Sol, H.; Sottile, G.; Sowiński, M.; Spanier,
   F.; Spiga, D.; Spyrou, S.; Stamatescu, V.; Stamerra, A.; Starling,
   R. L. C.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Steiner, S.;
   Stella, C.; Stergioulas, N.; Sternberger, R.; Sterzel, M.; Stinzing,
   F.; Stodulski, M.; Stolarczyk, Th.; Straumann, U.; Strazzeri, E.;
   Stringhetti, L.; Suarez, A.; Suchenek, M.; Sugawara, R.; Sulanke,
   K. -H.; Sun, S.; Supanitsky, A. D.; Suric, T.; Sutcliffe, P.; Sykes,
   J. M.; Szanecki, M.; Szepieniec, T.; Szostek, A.; Tagliaferri, G.;
   Tajima, H.; Takahashi, H.; Takahashi, K.; Takalo, L.; Takami, H.;
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   M.; Tavernet, J. -P.; Tejedor, L. A.; Telezhinsky, I.; Temnikov, P.;
   Tenzer, C.; Terada, Y.; Terrier, R.; Teshima, M.; Testa, V.; Tezier,
   D.; Thayer, J.; Thuermann, D.; Tibaldo, L.; Tibaldo, L.; Tibolla,
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   Tornikoski, M.; Torres, D. F.; Torres, M.; Toscano, S.; Toso, G.;
   Tosti, G.; Totani, T.; Toussenel, F.; Tovmassian, G.; Travnicek, P.;
   Treves, A.; Trifoglio, M.; Troyano, I.; Tsinganos, K.; Ueno, H.; Umana,
   G.; Umehara, K.; Upadhya, S. S.; Usher, T.; Uslenghi, M.; Vagnetti, F.;
   Valdes-Galicia, J. F.; Vallania, P.; Vallejo, G.; van Driel, W.; van
   Eldik, C.; Vandenbrouke, J.; Vanderwalt, J.; Vankov, H.; Vasileiadis,
   G.; Vassiliev, V.; Veberic, D.; Vegas, I.; Vercellone, S.; Vergani,
   S.; Verzi, V.; Vettolani, G. P.; Veyssière, C.; Vialle, J. P.;
   Viana, A.; Videla, M.; Vigorito, C.; Vincent, P.; Vincent, S.; Vink,
   J.; Vlahakis, N.; Vlahos, L.; Vogler, P.; Voisin, V.; Vollhardt, A.;
   von Gunten, H. -P.; Vorobiov, S.; Vuerli, C.; Waegebaert, V.; Wagner,
   R.; Wagner, R. G.; Wagner, S.; Wakely, S. P.; Walter, R.; Walther,
   T.; Warda, K.; Warwick, R. S.; Wawer, P.; Wawrzaszek, R.; Webb, N.;
   Wegner, P.; Weinstein, A.; Weitzel, Q.; Welsing, R.; Werner, M.;
   Wetteskind, H.; White, R. J.; Wierzcholska, A.; Wiesand, S.; Wilhelm,
   A.; Wilkinson, M. I.; Williams, D. A.; Willingale, R.; Winde, M.;
   Winiarski, K.; Wischnewski, R.; Wiśniewski, Ł.; Wojcik, P.; Wood,
   M.; Wörnlein, A.; Xiong, Q.; Yadav, K. K.; Yamamoto, H.; Yamamoto,
   T.; Yamazaki, R.; Yanagita, S.; Yebras, J. M.; Yelos, D.; Yoshida,
   A.; Yoshida, T.; Yoshikoshi, T.; Yu, P.; Zabalza, V.; Zacharias, M.;
   Zajczyk, A.; Zampieri, L.; Zanin, R.; Zdziarski, A.; Zech, A.; Zhao,
   A.; Zhou, X.; Zietara, K.; Ziolkowski, J.; Ziółkowski, P.; Zitelli,
   V.; Zurbach, C.; Zychowski, P.
Bibcode: 2013arXiv1307.2232C
Altcode:
  Compilation of CTA contributions to the proceedings of the 33rd
  International Cosmic Ray Conference (ICRC2013), which took place in
  2-9 July, 2013, in Rio de Janeiro, Brazil

Title: Can Surface Flux Transport Account for the Weak Polar Field
    in Cycle 23?
Authors: Jiang, Jie; Cameron, Robert H.; Schmitt, Dieter; Schüssler,
   Manfred
Bibcode: 2013SSRv..176..289J
Altcode: 2011SSRv..tmp..212J; 2011SSRv..tmp...69J; 2011arXiv1104.4183J;
   2011SSRv..tmp..136J; 2011SSRv..tmp..368J
  To reproduce the weak magnetic field on the polar caps of the Sun
  observed during the declining phase of cycle 23 poses a challenge to
  surface flux transport models since this cycle has not been particularly
  weak. We use a well-calibrated model to evaluate the parameter changes
  required to obtain simulated polar fields and open flux that are
  consistent with the observations. We find that the low polar field
  of cycle 23 could be reproduced by an increase of the meridional flow
  by 55% in the last cycle. Alternatively, a decrease of the mean tilt
  angle of sunspot groups by 28% would also lead to a similarly low polar
  field, but cause a delay of the polar field reversals by 1.5 years in
  comparison to the observations.

Title: First evidence of interaction between longitudinal and
    transverse waves in solar magnetic elements
Authors: Stangalini, M.; Solanki, S. K.; Cameron, R.; Martínez
   Pillet, V.
Bibcode: 2013A&A...554A.115S
Altcode: 2013arXiv1304.7088S
  Small-scale magnetic fields are thought to play an important role in
  the heating of the outer solar atmosphere. By taking advantage of
  the unprecedented high-spatial and temporal cadence of the Imaging
  Magnetograph eXperiment (IMaX), the filter vector polarimeter on board
  the Sunrise balloon-borne observatory, we study the transversal and
  longitudinal velocity oscillations in small magnetic elements. The
  results of this analysis are then compared to magnetohydrodynamic (MHD)
  simulations, showing excellent agreement. We found buffeting-induced
  transverse oscillations with velocity amplitudes of the order of 1-2
  km s<SUP>-1</SUP> to be common along with longitudinal oscillations
  with amplitudes ~0.4 km s<SUP>-1</SUP>. Moreover, we also found an
  interaction between transverse oscillations and longitudinal velocity
  oscillations, showing a ± 90° phase lag at the frequency at which
  they exhibit the maximum coherence in the power spectrum. Our results
  are consistent with the theoretical picture in which MHD longitudinal
  waves are excited inside small magnetic elements as a response of the
  flux tube to the forcing action of the granular flows.

Title: Modeling solar cycles 15 to 21 using a flux transport dynamo
Authors: Jiang, J.; Cameron, R. H.; Schmitt, D.; Işık, E.
Bibcode: 2013A&A...553A.128J
Altcode: 2013arXiv1304.5730J
  Context. The Sun's polar fields and open flux around the time of
  activity minima have been considered to be strongly correlated with
  the strength of the subsequent maximum of solar activity. <BR /> Aims:
  We aim to investigate the behavior of a Babcock-Leighton dynamo with
  a source poloidal term that is based on the observed sunspot areas
  and tilts. In particular, we investigate whether the toroidal fields
  at the base of convection zone from the model are correlated with the
  observed solar cycle activity maxima. <BR /> Methods: We used a flux
  transport dynamo model that includes convective pumping and a poloidal
  source term based on the historical record of sunspot group areas,
  locations, and tilt angles to simulate solar cycles 15 to 21. <BR />
  Results: We find that the polar fields near minima and the toroidal
  flux at the base of the convection zone are both highly correlated
  with the subsequent maxima of solar activity levels (r = 0.85 and r =
  0.93, respectively). <BR /> Conclusions: The Babcock-Leighton dynamo
  is consistent with the observationally inferred correlations.

Title: ATCA follow-up of unidentified flaring Fermi gamma-ray sources
Authors: Corbel, Stephane; Edwards, Philip; Sadler, Elaine; Ojha,
   Roopesh; Thompson, David J.; Gehrels, Neil; Tingay, Steven; Cheung,
   Teddy; Wieringa, Mark; Grenier, Isabelle; Chaty, Sylvain; Dubus,
   Guillaume; Cameron, Robert; Abraham, Falcone; Schinzel, Frank
Bibcode: 2013atnf.prop.5452C
Altcode:
  This NAPA proposal will be triggered by the detection of a
  gamma-ray flare with the Large Area Telescope on the Fermi gamma-ray
  satellite. The Fermi team will identify bright sources flaring on
  day-timescales to trigger ATCA observations for southern sources for
  which no counterpart is known, which we expect to occur predominantly
  for sources with |b|&lt;1.5degrees. As Fermi source localizations
  are often better than 10arcmin, we will initially make simultaneous
  5GHz/9GHz observation, for which the primary beam is matched to the
  Fermi error region. If a radio counterpart can be identified, we will
  make follow-up observations at higher frequencies to help characterise
  the Spectral Energy Distribution of the source, and to monitor the
  evolution of the outburst at radio frequencies. History indicates
  this rapid localization and follow-up of flaring sources may well be
  critical in identifying a new class (or classes) of high energy object.

Title: Introducing the CTA concept
Authors: Acharya, B. S.; Actis, M.; Aghajani, T.; Agnetta, G.;
   Aguilar, J.; Aharonian, F.; Ajello, M.; Akhperjanian, A.; Alcubierre,
   M.; Aleksić, J.; Alfaro, R.; Aliu, E.; Allafort, A. J.; Allan, D.;
   Allekotte, I.; Amato, E.; Anderson, J.; Angüner, E. O.; Antonelli,
   L. A.; Antoranz, P.; Aravantinos, A.; Arlen, T.; Armstrong, T.;
   Arnaldi, H.; Arrabito, L.; Asano, K.; Ashton, T.; Asorey, H. G.; Awane,
   Y.; Baba, H.; Babic, A.; Baby, N.; Bähr, J.; Bais, A.; Baixeras, C.;
   Bajtlik, S.; Balbo, M.; Balis, D.; Balkowski, C.; Bamba, A.; Bandiera,
   R.; Barber, A.; Barbier, C.; Barceló, M.; Barnacka, A.; Barnstedt, J.;
   Barres de Almeida, U.; Barrio, J. A.; Basili, A.; Basso, S.; Bastieri,
   D.; Bauer, C.; Baushev, A.; Becerra, J.; Becherini, Y.; Bechtol, K. C.;
   Becker Tjus, J.; Beckmann, V.; Bednarek, W.; Behera, B.; Belluso,
   M.; Benbow, W.; Berdugo, J.; Berger, K.; Bernard, F.; Bernardino, T.;
   Bernlöhr, K.; Bhat, N.; Bhattacharyya, S.; Bigongiari, C.; Biland,
   A.; Billotta, S.; Bird, T.; Birsin, E.; Bissaldi, E.; Biteau, J.;
   Bitossi, M.; Blake, S.; Blanch Bigas, O.; Blasi, P.; Bobkov, A.;
   Boccone, V.; Boettcher, M.; Bogacz, L.; Bogart, J.; Bogdan, M.;
   Boisson, C.; Boix Gargallo, J.; Bolmont, J.; Bonanno, G.; Bonardi,
   A.; Bonev, T.; Bonifacio, P.; Bonnoli, G.; Bordas, P.; Borgland,
   A.; Borkowski, J.; Bose, R.; Botner, O.; Bottani, A.; Bouchet, L.;
   Bourgeat, M.; Boutonnet, C.; Bouvier, A.; Brau-Nogué, S.; Braun, I.;
   Bretz, T.; Briggs, M.; Bringmann, T.; Brook, P.; Brun, P.; Brunetti,
   L.; Buanes, T.; Buckley, J.; Buehler, R.; Bugaev, V.; Bulgarelli, A.;
   Bulik, T.; Busetto, G.; Buson, S.; Byrum, K.; Cailles, M.; Cameron,
   R.; Camprecios, J.; Canestrari, R.; Cantu, S.; Capalbi, M.; Caraveo,
   P.; Carmona, E.; Carosi, A.; Carr, J.; Carton, P. -H.; Casanova,
   S.; Casiraghi, M.; Catalano, O.; Cavazzani, S.; Cazaux, S.; Cerruti,
   M.; Chabanne, E.; Chadwick, P.; Champion, C.; Chen, A.; Chiang, J.;
   Chiappetti, L.; Chikawa, M.; Chitnis, V. R.; Chollet, F.; Chudoba, J.;
   Cieślar, M.; Cillis, A.; Cohen-Tanugi, J.; Colafrancesco, S.; Colin,
   P.; Colome, J.; Colonges, S.; Compin, M.; Conconi, P.; Conforti, V.;
   Connaughton, V.; Conrad, J.; Contreras, J. L.; Coppi, P.; Corona, P.;
   Corti, D.; Cortina, J.; Cossio, L.; Costantini, H.; Cotter, G.; Courty,
   B.; Couturier, S.; Covino, S.; Crimi, G.; Criswell, S. J.; Croston,
   J.; Cusumano, G.; Dafonseca, M.; Dale, O.; Daniel, M.; Darling, J.;
   Davids, I.; Dazzi, F.; De Angelis, A.; De Caprio, V.; De Frondat,
   F.; de Gouveia Dal Pino, E. M.; de la Calle, I.; De La Vega, G. A.;
   de los Reyes Lopez, R.; De Lotto, B.; De Luca, A.; de Mello Neto,
   J. R. T.; de Naurois, M.; de Oliveira, Y.; de Oña Wilhelmi, E.;
   de Souza, V.; Decerprit, G.; Decock, G.; Deil, C.; Delagnes, E.;
   Deleglise, G.; Delgado, C.; Della Volpe, D.; Demange, P.; Depaola,
   G.; Dettlaff, A.; Di Paola, A.; Di Pierro, F.; Díaz, C.; Dick, J.;
   Dickherber, R.; Dickinson, H.; Diez-Blanco, V.; Digel, S.; Dimitrov,
   D.; Disset, G.; Djannati-Ataï, A.; Doert, M.; Dohmke, M.; Domainko,
   W.; Dominis Prester, D.; Donat, A.; Dorner, D.; Doro, M.; Dournaux,
   J. -L.; Drake, G.; Dravins, D.; Drury, L.; Dubois, F.; Dubois, R.;
   Dubus, G.; Dufour, C.; Dumas, D.; Dumm, J.; Durand, D.; Dyks, J.;
   Dyrda, M.; Ebr, J.; Edy, E.; Egberts, K.; Eger, P.; Einecke, S.;
   Eleftheriadis, C.; Elles, S.; Emmanoulopoulos, D.; Engelhaupt, D.;
   Enomoto, R.; Ernenwein, J. -P.; Errando, M.; Etchegoyen, A.; Evans,
   P.; Falcone, A.; Fantinel, D.; Farakos, K.; Farnier, C.; Fasola,
   G.; Favill, B.; Fede, E.; Federici, S.; Fegan, S.; Feinstein, F.;
   Ferenc, D.; Ferrando, P.; Fesquet, M.; Fiasson, A.; Fillin-Martino,
   E.; Fink, D.; Finley, C.; Finley, J. P.; Fiorini, M.; Firpo Curcoll,
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   Zhao, A.; Zhou, X.; Ziętara, K.; Ziolkowski, J.; Ziółkowski, P.;
   Zitelli, V.; Zurbach, C.; Żychowski, P.; CTA Consortium
Bibcode: 2013APh....43....3A
Altcode: 2013APh....43....3C
  The Cherenkov Telescope Array (CTA) is a new observatory for very
  high-energy (VHE) gamma rays. CTA has ambitions science goals, for which
  it is necessary to achieve full-sky coverage, to improve the sensitivity
  by about an order of magnitude, to span about four decades of energy,
  from a few tens of GeV to above 100 TeV with enhanced angular and energy
  resolutions over existing VHE gamma-ray observatories. An international
  collaboration has formed with more than 1000 members from 27 countries
  in Europe, Asia, Africa and North and South America. In 2010 the CTA
  Consortium completed a Design Study and started a three-year Preparatory
  Phase which leads to production readiness of CTA in 2014. In this paper
  we introduce the science goals and the concept of CTA, and provide an
  overview of the project.

Title: Coupled model for the formation of an active region corona
Authors: Chen, Feng; Bingert, Sven; Peter, Hardi; Cameron, Robert;
   Schüssler; , Manfred; Cheung, Mark C. M.
Bibcode: 2013enss.confE..21C
Altcode:
  We will present the first model that couples the formation of an active
  region corona to a model of the emergence. This allows us to study
  when, where, and why active region loops form, and how they evolve. For
  this we use an existing 3D radiation MHD model of the emergence of an
  active region through the upper convection zone and the photosphere
  as a lower boundary for a coronal model. Our 3D MHD coronal model
  accounts for the braiding of the magnetic field lines that induces
  currents in the corona that is getting filled with the emerging magnetic
  field. Starting with a basically field-free atmosphere we follow the
  flux emergence until numerous individually identifiable hot coronal
  loops have been formed. The temperatures in the coronal loops of well
  above 1 MK are reached at densities corresponding to actually observed
  active region loops. The loops develop over a very short time period
  of the order of several minutes through the evaporation of material
  from the chromosphere. Because we have full access to the heating
  rate as a function of time and space in our computational domain we
  can determine the conditions under which these loops form.

Title: On the relation between continuum brightness and magnetic
    field in solar active regions
Authors: Danilovic, S.; Röhrbein, D.; Cameron, R. H.; Schüssler, M.
Bibcode: 2013A&A...550A.118D
Altcode:
  Context. Variations of solar irradiance are mainly determined
  by the changing coverage of the visible solar disk with magnetic
  flux concentrations. The relationship between brightness and field
  strength is an important ingredient for models and reconstructions of
  irradiance variations. <BR /> Aims: We assess the effect of limited
  observational resolution on the relationship between brightness
  and magnetic field by comparing comprehensive MHD simulations with
  observational results. <BR /> Methods: Simulations of magnetoconvection
  representing the near-surface layers of a plage region were used to
  determine maps of the continuum brightness and Stokes profiles for the
  Fe i line at 630.22 nm. After convolving with instrumental profiles,
  synthetic observations of the magnetic field were generated by applying
  a Stokes inversion code. We compare the resulting relation between
  brightness and apparent vertical magnetic field to the corresponding
  outcome derived from real observations of a plage region with the
  Hinode satellite. <BR /> Results: Consideration of the image smearing
  effects due to the limited resolution of the observations transform the
  largely monotonic relation between brightness and field strength at the
  original resolution of the simulations into a profile with a maximum
  at intermediate field strength, which is in good agreement with the
  observations. <BR /> Conclusions: Considering the effect of limited
  observational resolution renders the relation between brightness and
  magnetic field from comprehensive MHD simulations consistent with
  observational results. This is a necessary prerequisite for the
  utilization of simulations for models and reconstruction of solar
  irradiance variations.

Title: MHD waves in small magnetic elements: comparing IMaX
    observations to simulations.
Authors: Stangalini, M.; Solanki, S. K.; Cameron, R.
Bibcode: 2013MmSAI..84..444S
Altcode:
  Small-scale magnetic fields are thought to play an important role in the
  heating of the outer solar atmosphere. By exploiting the high-spatial
  and temporal resolution of IMaX, the bidimensional spectropolarimeter on
  board the Sunrise balloon-borne observatory, we study the excitation of
  MHD waves in small magnetic elements, providing clues on the interaction
  of the magnetic structures with the photospheric forcing and the ambient
  acoustic field. The large fraction of magnetic features observed by
  IMaX made it possible to study the interaction between the photospheric
  granulation and the flux tubes from a statistical point-of-view. In
  particular we find a 90 degree phase lag with an high confidence level
  between the horizontal displacements of the flux tubes and the velocity
  perturbations measured inside them. We also find that the observational
  results are in excellent agreement with MHD simulations. This result
  suggests that the horizontal displacement of small-scale magnetic
  features by the surrounding granulation excites longitudinal waves
  within the magnetic elements.

Title: MHD simulation of the inner-heliospheric magnetic field
Authors: Wiengarten, T.; Kleimann, J.; Fichtner, H.; Cameron, R.;
   Jiang, J.; Kissmann, R.; Scherer, K.
Bibcode: 2013JGRA..118...29W
Altcode: 2013arXiv1303.4260W
  Maps of the radial magnetic field at a heliocentric distance of 10
  solar radii are used as boundary conditions in the MHD code CRONOS to
  simulate a three-dimensional inner-heliospheric solar wind emanating
  from the rotating Sun out to 1 AU. The input data for the magnetic
  field are the result of solar surface flux transport modeling using
  observational data of sunspot groups coupled with a current-sheet
  source surface model. Among several advancements, this allows for
  higher angular resolution than that of comparable observational data
  from synoptic magnetograms. The required initial conditions for the
  other MHD quantities are obtained following an empirical approach using
  an inverse relation between flux tube expansion and radial solar wind
  speed. The computations are performed for representative solar minimum
  and maximum conditions, and the corresponding state of the solar wind
  up to the Earth's orbit is obtained. After a successful comparison
  of the latter with observational data, they can be used to drive
  outer-heliospheric models.

Title: Are the strengths of solar cycles determined by converging
    flows towards the activity belts?
Authors: Cameron, R. H.; Schüssler, M.
Bibcode: 2012A&A...548A..57C
Altcode: 2012arXiv1210.7644C
  It is proposed that the observed near-surface inflows towards the
  active regions and sunspot zones provide a nonlinear feedback mechanism
  that limits the amplitude of a Babcock-Leighton-type solar dynamo and
  determines the variation of the cycle strength. This hypothesis is
  tested with surface flux transport simulations including converging
  latitudinal flows that depend on the surface distribution of magnetic
  flux. The inflows modulate the build-up of polar fields (represented
  by the axial dipole) by reducing the tilt angles of bipolar magnetic
  regions and by affecting the cross-equator transport of leading-polarity
  magnetic flux. With flux input derived from the observed record of
  sunspot groups, the simulations cover the period between 1874 and 1980
  (corresponding to solar cycles 11 to 20). The inclusion of the inflows
  leads to a strong correlation of the simulated axial dipole strength
  during activity minimum with the observed amplitude of the subsequent
  cycle. This in agreement with empirical correlations and in line with
  what is expected from a Babcock-Leighton-type dynamo. The results
  provide evidence that the latitudinal inflows are a key ingredient in
  determining the amplitude of solar cycles.

Title: ATCA follow-up of unidentified flaring Fermi gamma-ray sources
Authors: Corbel, Stephane; Edwards, Philip; Sadler, Elaine; Thompson,
   David J.; Gehrels, Neil; Tingay, Steven; Wieringa, Mark; Grenier,
   Isabelle; Chaty, Sylvain; Dubus, Guillaume; Cameron, Robert; Abraham,
   Falcone
Bibcode: 2012atnf.prop.5094C
Altcode:
  This NAPA proposal will be triggered by the detection of a
  gamma-ray flare with the Large Area Telescope on the Fermi gamma-ray
  satellite. The Fermi team will identify bright sources flaring on
  day-timescales to trigger ATCA observations for southern sources for
  which no counterpart is known, which we expect to occur predominantly
  for sources with |b|&lt;1.5degrees. As Fermi source localizations
  are often better than 10arcmin, we will initially make simultaneous
  5GHz/9GHz observation, for which the primary beam is matched to the
  Fermi error region. If a radio counterpart can be identified, we will
  make follow-up observations at higher frequencies to help characterise
  the Spectral Energy Distribution of the source, and to monitor the
  evolution of the outburst at radio frequencies. History indicates
  this rapid localization and follow-up of flaring sources may well be
  critical in identifying a new class (or classes) of high energy object.

Title: Surface flux evolution constraints for flux transport dynamos
Authors: Cameron, R. H.; Schmitt, D.; Jiang, J.; Işık, E.
Bibcode: 2012A&A...542A.127C
Altcode: 2012arXiv1205.1136C
  The surface flux transport (SFT) model of solar magnetic fields involves
  empirically well-constrained velocity and magnetic fields. The basic
  evolution of the Sun's large-scale surface magnetic field is well
  described by this model. The azimuthally averaged evolution of the SFT
  model can be compared to the surface evolution of the flux transport
  dynamo (FTD), and the evolution of the SFT model can be used to
  constrain several near-surface properties of the FTD model. We compared
  the results of the FTD model with different upper boundary conditions
  and diffusivity profiles against the results of the SFT model. Among
  the ingredients of the FTD model, downward pumping of magnetic flux,
  related to a positive diffusivity gradient, has a significant effect
  in slowing down the diffusive radial transport of magnetic flux through
  the solar surface. Provided the pumping was strong enough to give rise
  to a downflow of a magnetic Reynolds number of 5 in the near-surface
  boundary layer, the FTD using a vertical boundary condition matches the
  SFT model based on the average velocities above the boundary layer. The
  FTD model with a potential field was unable to match the SFT results.

Title: Waves as the Source of Apparent Twisting Motions in Sunspot
    Penumbrae
Authors: Bharti, L.; Cameron, R. H.; Rempel, M.; Hirzberger, J.;
   Solanki, S. K.
Bibcode: 2012ApJ...752..128B
Altcode: 2012arXiv1204.2221B
  The motion of dark striations across bright filaments in a sunspot
  penumbra has become an important new diagnostic of convective gas
  flows in penumbral filaments. The nature of these striations has,
  however, remained unclear. Here, we present an analysis of small-scale
  motions in penumbral filaments in both simulations and observations. The
  simulations, when viewed from above, show fine structure with dark lanes
  running outward from the dark core of the penumbral filaments. The
  dark lanes either occur preferentially on one side or alternate
  between both sides of the filament. We identify this fine structure
  with transverse (kink) oscillations of the filament, corresponding to
  a sideways swaying of the filament. These oscillations have periods in
  the range of 5-7 minutes and propagate outward and downward along the
  filament. Similar features are found in observed G-band intensity time
  series of penumbral filaments in a sunspot located near disk center
  obtained by the Broadband Filter Imager on board the Hinode. We also
  find that some filaments show dark striations moving to both sides
  of the filaments. Based on the agreement between simulations and
  observations we conclude that the motions of these striations are
  caused by transverse oscillations of the underlying bright filaments.

Title: Vortices, shocks, and heating in the solar photosphere:
    effect of a magnetic field
Authors: Moll, R.; Cameron, R. H.; Schüssler, M.
Bibcode: 2012A&A...541A..68M
Altcode: 2012arXiv1201.5981M
  <BR /> Aims: We study the differences between non-magnetic and
  magnetic regions in the flow and thermal structure of the upper solar
  photosphere. <BR /> Methods: Radiative MHD simulations representing
  a quiet region and a plage region, respectively, which extend into
  the layers around the temperature minimum, are analyzed. <BR />
  Results: The flow structure in the upper photospheric layers of the
  two simulations is considerably different: the non-magnetic simulation
  is dominated by a pattern of moving shock fronts while the magnetic
  simulation shows vertically extended vortices associated with magnetic
  flux concentrations. Both kinds of structures induce substantial local
  heating. The resulting average temperature profiles are characterized by
  a steep rise above the temperature minimum due to shock heating in the
  non-magnetic case and by a flat photospheric temperature gradient mainly
  caused by Ohmic dissipation in the magnetic run. <BR /> Conclusions:
  Shocks in the quiet Sun and vortices in the strongly magnetized
  regions represent the dominant flow structures in the layers around
  the temperature minimum. They are closely connected with dissipation
  processes providing localized heating.

Title: Magnetohydrodynamics of the Weakly Ionized Solar Photosphere
Authors: Cheung, Mark C. M.; Cameron, Robert H.
Bibcode: 2012ApJ...750....6C
Altcode: 2012arXiv1202.1937C
  We investigate the importance of ambipolar diffusion and Hall
  currents for high-resolution comprehensive ("realistic") photospheric
  simulations. To do so, we extended the radiative magnetohydrodynamics
  code MURaM to use the generalized Ohm's law under the assumption
  of local thermodynamic equilibrium. We present test cases comparing
  analytical solutions with numerical simulations for validation of the
  code. Furthermore, we carried out a number of numerical experiments
  to investigate the impact of these neutral-ion effects in the
  photosphere. We find that, at the spatial resolutions currently used
  (5-20 km per grid point), the Hall currents and ambipolar diffusion
  begin to become significant—with flows of 100 m s<SUP>-1</SUP> in
  sunspot light bridges, and changes of a few percent in the thermodynamic
  structure of quiet-Sun magnetic features. The magnitude of the effects
  is expected to increase rapidly as smaller-scale variations are resolved
  by the simulations.

Title: Break up of returning plasma after the 7 June 2011 filament
    eruption by Rayleigh-Taylor instabilities
Authors: Innes, D. E.; Cameron, R. H.; Fletcher, L.; Inhester, B.;
   Solanki, S. K.
Bibcode: 2012A&A...540L..10I
Altcode: 2012arXiv1202.4981I
  Context. A prominence eruption on 7 June 2011 produced spectacular
  curtains of plasma falling through the lower corona. At the solar
  surface they created an incredible display of extreme ultraviolet
  brightenings. <BR /> Aims: To identify and analyze some of the local
  instabilities which produce structure in the falling plasma. <BR />
  Methods: The structures were investigated using SDO/AIA 171 Å and
  193 Å images in which the falling plasma appeared dark against
  the bright coronal emission. <BR /> Results: Several instances of
  the Rayleigh-Taylor instability were investigated. In two cases the
  Alfvén velocity associated with the dense plasma could be estimated
  from the separation of the Rayleigh-Taylor fingers. A second type of
  feature, which has the appearance of self-similar branching horns was
  discussed. <P />Appendix A and two movies are available in electronic
  form at <A href="http://www.aanda.org">http://www.aanda.org</A>

Title: ATCA follow-up of unidentified flaring Fermi gamma-ray sources
Authors: Corbel, Stephane; Edwards, Philip; Sadler, Elaine; Thompson,
   David J.; Gehrels, Neil; Tingay, Steven; Wieringa, Mark; Grenier,
   Isabelle; Chaty, Sylvain; Dubus, Guillaume; Cameron, Robert; Abraham,
   Falcone
Bibcode: 2012atnf.prop.4533C
Altcode:
  This NAPA proposal will be triggered by the detection of a
  gamma-ray flare with the Large Area Telescope on the Fermi gamma-ray
  satellite. The Fermi team will identify bright sources flaring on
  day-timescales to trigger ATCA observations for southern sources for
  which no counterpart is known, which we expect to occur predominantly
  for sources with |b|&lt;1.5degrees. As Fermi source localizations
  are often better than 10arcmin, we will initially make simultaneous
  5GHz/9GHz observation, for which the primary beam is matched to the
  Fermi error region. If a radio counterpart can be identified, we will
  make follow-up observations at higher frequencies to help characterise
  the Spectral Energy Distribution of the source, and to monitor the
  evolution of the outburst at radio frequencies. History indicates
  this rapid localization and follow-up of flaring sources may well be
  critical in identifying a new class (or classes) of high energy object.

Title: Diffusivity of Isolated Internetwork Ca II H Bright Points
    Observed by SuFI/SUNRISE
Authors: Jafarzadeh, S.; Solanki, S. K.; Cameron, R. H.; Feller, A.;
   Pietarila, A.; Lagg, A.; Barthol, P.; Berkefeld, T.; Gandorfer, A.;
   Knoelker, M.; Martinez Pillet, V.; Schmidt, W.; Title, A.
Bibcode: 2012decs.confE..99J
Altcode:
  We analyze trajectories of the proper motion of intrinsically magnetic,
  isolated internetwork Ca II H BPs (with mean lifetime of 461 sec) to
  obtain their diffusivity behaviors. We use high spatial and temporal
  resolution image sequences of quiet-Sun, disc-centre observations
  obtained in the Ca II H 397 nm passband of the Sunrise Filter Imager
  (SuFI) on board the SUNRISE balloon-borne solar observatory. In
  order to avoid misidentification, the BPs are semi-manually selected
  and then automatically tracked. The trajectory of each BP is then
  calculated and its diffusion index is described by a power law
  exponent, using which we classify the BPs' trajectories into sub-,
  normal and super- diffusive. In addition, the corresponding diffusion
  coefficients (D) based on the observed displacements are consequently
  computed. We find a strong super-diffusivity at a height sampled by the
  SuFI/SUNRISE Ca II H passband (i.e. a height corresponding roughly to
  the temperature minimum). We find that 74% of the identified tiny BPs
  are super-diffusive, 18% move randomly (i.e. their motion corresponds
  to normal diffusion) and only 8% belong to the sub-diffusion regime. In
  addition, we find that 53% of the super-diffusion regime (i.e. 39% of
  all BPs) have the diffusivity index of 2 which are termed as "Ballistic
  BPs". Finally, we explore the distribution of diffusion index with the
  help of a simple simulation. The results suggest that the BPs are random
  walkers superposed by a systematic (background) velocity in which the
  magnitude of each component (and hence their ratio) depends on the time
  and spatial scales. We further discuss a simple sketch to explain the
  diffusivity of observed BPs while they migrate within a supergranule
  (i.e. internetwork areas) or close to the network regions.

Title: To the top of the photosphere
Authors: Cameron, Robert
Bibcode: 2012decs.confE..17C
Altcode:
  We will discuss the interaction of convection and magnetic fields in
  the solar photosphere. In particular we will concentrate on the broad
  range of time and spatial scales over which structures are generated
  and evolve. The importance of waves, vortices and braiding of the
  magnetic footpoints will be mentioned, as well as future problems
  which need to be tackled.

Title: Simulations of the solar near-surface layers with the CO5BOLD,
    MURaM, and Stagger codes
Authors: Beeck, B.; Collet, R.; Steffen, M.; Asplund, M.; Cameron,
   R. H.; Freytag, B.; Hayek, W.; Ludwig, H. -G.; Schüssler, M.
Bibcode: 2012A&A...539A.121B
Altcode: 2012arXiv1201.1103B
  Context. Radiative hydrodynamic simulations of solar and stellar surface
  convection have become an important tool for exploring the structure and
  gas dynamics in the envelopes and atmospheres of late-type stars and for
  improving our understanding of the formation of stellar spectra. <BR
  /> Aims: We quantitatively compare results from three-dimensional,
  radiative hydrodynamic simulations of convection near the solar surface
  generated with three numerical codes (CO<SUP>5</SUP>BOLD, MURaM,
  and Stagger) and different simulation setups in order to investigate
  the level of similarity and to cross-validate the simulations. <BR
  /> Methods: For all three simulations, we considered the average
  stratifications of various quantities (temperature, pressure, flow
  velocity, etc.) on surfaces of constant geometrical or optical depth,
  as well as their temporal and spatial fluctuations. We also compared
  observables, such as the spatially resolved patterns of the emerging
  intensity and of the vertical velocity at the solar optical surface
  as well as the center-to-limb variation of the continuum intensity
  at various wavelengths. <BR /> Results: The depth profiles of the
  thermodynamical quantities and of the convective velocities as well as
  their spatial fluctuations agree quite well. Slight deviations can be
  understood in terms of differences in box size, spatial resolution
  and in the treatment of non-gray radiative transfer between the
  simulations. <BR /> Conclusions: The results give confidence in the
  reliability of the results from comprehensive radiative hydrodynamic
  simulations.

Title: Design concepts for the Cherenkov Telescope Array CTA: an
    advanced facility for ground-based high-energy gamma-ray astronomy
Authors: Actis, M.; Agnetta, G.; Aharonian, F.; Akhperjanian,
   A.; Aleksić, J.; Aliu, E.; Allan, D.; Allekotte, I.; Antico, F.;
   Antonelli, L. A.; Antoranz, P.; Aravantinos, A.; Arlen, T.; Arnaldi,
   H.; Artmann, S.; Asano, K.; Asorey, H.; Bähr, J.; Bais, A.; Baixeras,
   C.; Bajtlik, S.; Balis, D.; Bamba, A.; Barbier, C.; Barceló, M.;
   Barnacka, A.; Barnstedt, J.; Barres de Almeida, U.; Barrio, J. A.;
   Basso, S.; Bastieri, D.; Bauer, C.; Becerra, J.; Becherini, Y.;
   Bechtol, K.; Becker, J.; Beckmann, V.; Bednarek, W.; Behera, B.;
   Beilicke, M.; Belluso, M.; Benallou, M.; Benbow, W.; Berdugo, J.;
   Berger, K.; Bernardino, T.; Bernlöhr, K.; Biland, A.; Billotta, S.;
   Bird, T.; Birsin, E.; Bissaldi, E.; Blake, S.; Blanch, O.; Bobkov,
   A. A.; Bogacz, L.; Bogdan, M.; Boisson, C.; Boix, J.; Bolmont,
   J.; Bonanno, G.; Bonardi, A.; Bonev, T.; Borkowski, J.; Botner, O.;
   Bottani, A.; Bourgeat, M.; Boutonnet, C.; Bouvier, A.; Brau-Nogué, S.;
   Braun, I.; Bretz, T.; Briggs, M. S.; Brun, P.; Brunetti, L.; Buckley,
   J. H.; Bugaev, V.; Bühler, R.; Bulik, T.; Busetto, G.; Buson, S.;
   Byrum, K.; Cailles, M.; Cameron, R.; Canestrari, R.; Cantu, S.;
   Carmona, E.; Carosi, A.; Carr, J.; Carton, P. H.; Casiraghi, M.;
   Castarede, H.; Catalano, O.; Cavazzani, S.; Cazaux, S.; Cerruti,
   B.; Cerruti, M.; Chadwick, P. M.; Chiang, J.; Chikawa, M.; Cieślar,
   M.; Ciesielska, M.; Cillis, A.; Clerc, C.; Colin, P.; Colomé, J.;
   Compin, M.; Conconi, P.; Connaughton, V.; Conrad, J.; Contreras, J. L.;
   Coppi, P.; Corlier, M.; Corona, P.; Corpace, O.; Corti, D.; Cortina,
   J.; Costantini, H.; Cotter, G.; Courty, B.; Couturier, S.; Covino,
   S.; Croston, J.; Cusumano, G.; Daniel, M. K.; Dazzi, F.; de Angelis,
   A.; de Cea Del Pozo, E.; de Gouveia Dal Pino, E. M.; de Jager, O.;
   de La Calle Pérez, I.; de La Vega, G.; de Lotto, B.; de Naurois,
   M.; de Oña Wilhelmi, E.; de Souza, V.; Decerprit, B.; Deil, C.;
   Delagnes, E.; Deleglise, G.; Delgado, C.; Dettlaff, T.; di Paolo,
   A.; di Pierro, F.; Díaz, C.; Dick, J.; Dickinson, H.; Digel, S. W.;
   Dimitrov, D.; Disset, G.; Djannati-Ataï, A.; Doert, M.; Domainko,
   W.; Dorner, D.; Doro, M.; Dournaux, J. -L.; Dravins, D.; Drury, L.;
   Dubois, F.; Dubois, R.; Dubus, G.; Dufour, C.; Durand, D.; Dyks,
   J.; Dyrda, M.; Edy, E.; Egberts, K.; Eleftheriadis, C.; Elles, S.;
   Emmanoulopoulos, D.; Enomoto, R.; Ernenwein, J. -P.; Errando, M.;
   Etchegoyen, A.; Falcone, A. D.; Farakos, K.; Farnier, C.; Federici,
   S.; Feinstein, F.; Ferenc, D.; Fillin-Martino, E.; Fink, D.; Finley,
   C.; Finley, J. P.; Firpo, R.; Florin, D.; Föhr, C.; Fokitis, E.;
   Font, Ll.; Fontaine, G.; Fontana, A.; Förster, A.; Fortson, L.;
   Fouque, N.; Fransson, C.; Fraser, G. W.; Fresnillo, L.; Fruck, C.;
   Fujita, Y.; Fukazawa, Y.; Funk, S.; Gäbele, W.; Gabici, S.; Gadola,
   A.; Galante, N.; Gallant, Y.; García, B.; García López, R. J.;
   Garrido, D.; Garrido, L.; Gascón, D.; Gasq, C.; Gaug, M.; Gaweda,
   J.; Geffroy, N.; Ghag, C.; Ghedina, A.; Ghigo, M.; Gianakaki, E.;
   Giarrusso, S.; Giavitto, G.; Giebels, B.; Giro, E.; Giubilato, P.;
   Glanzman, T.; Glicenstein, J. -F.; Gochna, M.; Golev, V.; Gómez
   Berisso, M.; González, A.; González, F.; Grañena, F.; Graciani,
   R.; Granot, J.; Gredig, R.; Green, A.; Greenshaw, T.; Grimm, O.;
   Grube, J.; Grudzińska, M.; Grygorczuk, J.; Guarino, V.; Guglielmi,
   L.; Guilloux, F.; Gunji, S.; Gyuk, G.; Hadasch, D.; Haefner, D.;
   Hagiwara, R.; Hahn, J.; Hallgren, A.; Hara, S.; Hardcastle, M. J.;
   Hassan, T.; Haubold, T.; Hauser, M.; Hayashida, M.; Heller, R.; Henri,
   G.; Hermann, G.; Herrero, A.; Hinton, J. A.; Hoffmann, D.; Hofmann,
   W.; Hofverberg, P.; Horns, D.; Hrupec, D.; Huan, H.; Huber, B.; Huet,
   J. -M.; Hughes, G.; Hultquist, K.; Humensky, T. B.; Huppert, J. -F.;
   Ibarra, A.; Illa, J. M.; Ingjald, J.; Inoue, Y.; Inoue, S.; Ioka, K.;
   Jablonski, C.; Jacholkowska, A.; Janiak, M.; Jean, P.; Jensen, H.;
   Jogler, T.; Jung, I.; Kaaret, P.; Kabuki, S.; Kakuwa, J.; Kalkuhl,
   C.; Kankanyan, R.; Kapala, M.; Karastergiou, A.; Karczewski, M.;
   Karkar, S.; Karlsson, N.; Kasperek, J.; Katagiri, H.; Katarzyński, K.;
   Kawanaka, N.; Kȩdziora, B.; Kendziorra, E.; Khélifi, B.; Kieda, D.;
   Kifune, T.; Kihm, T.; Klepser, S.; Kluźniak, W.; Knapp, J.; Knappy,
   A. R.; Kneiske, T.; Knödlseder, J.; Köck, F.; Kodani, K.; Kohri,
   K.; Kokkotas, K.; Komin, N.; Konopelko, A.; Kosack, K.; Kossakowski,
   R.; Kostka, P.; Kotuła, J.; Kowal, G.; Kozioł, J.; Krähenbühl,
   T.; Krause, J.; Krawczynski, H.; Krennrich, F.; Kretzschmann, A.;
   Kubo, H.; Kudryavtsev, V. A.; Kushida, J.; La Barbera, N.; La Parola,
   V.; La Rosa, G.; López, A.; Lamanna, G.; Laporte, P.; Lavalley, C.;
   Le Flour, T.; Le Padellec, A.; Lenain, J. -P.; Lessio, L.; Lieunard,
   B.; Lindfors, E.; Liolios, A.; Lohse, T.; Lombardi, S.; Lopatin,
   A.; Lorenz, E.; Lubiński, P.; Luz, O.; Lyard, E.; Maccarone, M. C.;
   Maccarone, T.; Maier, G.; Majumdar, P.; Maltezos, S.; Małkiewicz,
   P.; Mañá, C.; Manalaysay, A.; Maneva, G.; Mangano, A.; Manigot,
   P.; Marín, J.; Mariotti, M.; Markoff, S.; Martínez, G.; Martínez,
   M.; Mastichiadis, A.; Matsumoto, H.; Mattiazzo, S.; Mazin, D.; McComb,
   T. J. L.; McCubbin, N.; McHardy, I.; Medina, C.; Melkumyan, D.; Mendes,
   A.; Mertsch, P.; Meucci, M.; Michałowski, J.; Micolon, P.; Mineo,
   T.; Mirabal, N.; Mirabel, F.; Miranda, J. M.; Mirzoyan, R.; Mizuno,
   T.; Moal, B.; Moderski, R.; Molinari, E.; Monteiro, I.; Moralejo, A.;
   Morello, C.; Mori, K.; Motta, G.; Mottez, F.; Moulin, E.; Mukherjee,
   R.; Munar, P.; Muraishi, H.; Murase, K.; Murphy, A. Stj.; Nagataki,
   S.; Naito, T.; Nakamori, T.; Nakayama, K.; Naumann, C.; Naumann, D.;
   Nayman, P.; Nedbal, D.; Niedźwiecki, A.; Niemiec, J.; Nikolaidis,
   A.; Nishijima, K.; Nolan, S. J.; Nowak, N.; O'Brien, P. T.; Ochoa,
   I.; Ohira, Y.; Ohishi, M.; Ohka, H.; Okumura, A.; Olivetto, C.; Ong,
   R. A.; Orito, R.; Orr, M.; Osborne, J. P.; Ostrowski, M.; Otero, L.;
   Otte, A. N.; Ovcharov, E.; Oya, I.; Oziȩbło, A.; Paiano, S.; Pallota,
   J.; Panazol, J. L.; Paneque, D.; Panter, M.; Paoletti, R.; Papyan,
   G.; Paredes, J. M.; Pareschi, G.; Parsons, R. D.; Paz Arribas, M.;
   Pedaletti, G.; Pepato, A.; Persic, M.; Petrucci, P. O.; Peyaud,
   B.; Piechocki, W.; Pita, S.; Pivato, G.; Płatos, Ł.; Platzer,
   R.; Pogosyan, L.; Pohl, M.; Pojmański, G.; Ponz, J. D.; Potter,
   W.; Prandini, E.; Preece, R.; Prokoph, H.; Pühlhofer, G.; Punch,
   M.; Quel, E.; Quirrenbach, A.; Rajda, P.; Rando, R.; Rataj, M.;
   Raue, M.; Reimann, C.; Reimann, O.; Reimer, A.; Reimer, O.; Renaud,
   M.; Renner, S.; Reymond, J. -M.; Rhode, W.; Ribó, M.; Ribordy,
   M.; Rico, J.; Rieger, F.; Ringegni, P.; Ripken, J.; Ristori, P.;
   Rivoire, S.; Rob, L.; Rodriguez, S.; Roeser, U.; Romano, P.; Romero,
   G. E.; Rosier-Lees, S.; Rovero, A. C.; Roy, F.; Royer, S.; Rudak, B.;
   Rulten, C. B.; Ruppel, J.; Russo, F.; Ryde, F.; Sacco, B.; Saggion, A.;
   Sahakian, V.; Saito, K.; Saito, T.; Sakaki, N.; Salazar, E.; Salini,
   A.; Sánchez, F.; Sánchez Conde, M. Á.; Santangelo, A.; Santos,
   E. M.; Sanuy, A.; Sapozhnikov, L.; Sarkar, S.; Scalzotto, V.; Scapin,
   V.; Scarcioffolo, M.; Schanz, T.; Schlenstedt, S.; Schlickeiser, R.;
   Schmidt, T.; Schmoll, J.; Schroedter, M.; Schultz, C.; Schultze, J.;
   Schulz, A.; Schwanke, U.; Schwarzburg, S.; Schweizer, T.; Seiradakis,
   J.; Selmane, S.; Seweryn, K.; Shayduk, M.; Shellard, R. C.; Shibata,
   T.; Sikora, M.; Silk, J.; Sillanpää, A.; Sitarek, J.; Skole, C.;
   Smith, N.; Sobczyńska, D.; Sofo Haro, M.; Sol, H.; Spanier, F.; Spiga,
   D.; Spyrou, S.; Stamatescu, V.; Stamerra, A.; Starling, R. L. C.;
   Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Steiner, S.; Stergioulas,
   N.; Sternberger, R.; Stinzing, F.; Stodulski, M.; Straumann, U.;
   Suárez, A.; Suchenek, M.; Sugawara, R.; Sulanke, K. H.; Sun, S.;
   Supanitsky, A. D.; Sutcliffe, P.; Szanecki, M.; Szepieniec, T.;
   Szostek, A.; Szymkowiak, A.; Tagliaferri, G.; Tajima, H.; Takahashi,
   H.; Takahashi, K.; Takalo, L.; Takami, H.; Talbot, R. G.; Tam, P. H.;
   Tanaka, M.; Tanimori, T.; Tavani, M.; Tavernet, J. -P.; Tchernin, C.;
   Tejedor, L. A.; Telezhinsky, I.; Temnikov, P.; Tenzer, C.; Terada,
   Y.; Terrier, R.; Teshima, M.; Testa, V.; Tibaldo, L.; Tibolla, O.;
   Tluczykont, M.; Todero Peixoto, C. J.; Tokanai, F.; Tokarz, M.; Toma,
   K.; Torres, D. F.; Tosti, G.; Totani, T.; Toussenel, F.; Vallania,
   P.; Vallejo, G.; van der Walt, J.; van Eldik, C.; Vandenbroucke, J.;
   Vankov, H.; Vasileiadis, G.; Vassiliev, V. V.; Vegas, I.; Venter, L.;
   Vercellone, S.; Veyssiere, C.; Vialle, J. P.; Videla, M.; Vincent,
   P.; Vink, J.; Vlahakis, N.; Vlahos, L.; Vogler, P.; Vollhardt, A.;
   Volpe, F.; von Gunten, H. P.; Vorobiov, S.; Wagner, S.; Wagner,
   R. M.; Wagner, B.; Wakely, S. P.; Walter, P.; Walter, R.; Warwick,
   R.; Wawer, P.; Wawrzaszek, R.; Webb, N.; Wegner, P.; Weinstein, A.;
   Weitzel, Q.; Welsing, R.; Wetteskind, H.; White, R.; Wierzcholska,
   A.; Wilkinson, M. I.; Williams, D. A.; Winde, M.; Wischnewski, R.;
   Wiśniewski, Ł.; Wolczko, A.; Wood, M.; Xiong, Q.; Yamamoto, T.;
   Yamaoka, K.; Yamazaki, R.; Yanagita, S.; Yoffo, B.; Yonetani, M.;
   Yoshida, A.; Yoshida, T.; Yoshikoshi, T.; Zabalza, V.; Zagdański,
   A.; Zajczyk, A.; Zdziarski, A.; Zech, A.; Ziȩtara, K.; Ziółkowski,
   P.; Zitelli, V.; Zychowski, P.
Bibcode: 2011ExA....32..193A
Altcode: 2011ExA...tmp..121A; 2010arXiv1008.3703C
  Ground-based gamma-ray astronomy has had a major breakthrough with
  the impressive results obtained using systems of imaging atmospheric
  Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge
  potential in astrophysics, particle physics and cosmology. CTA is
  an international initiative to build the next generation instrument,
  with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV
  range and the extension to energies well below 100 GeV and above 100
  TeV. CTA will consist of two arrays (one in the north, one in the south)
  for full sky coverage and will be operated as open observatory. The
  design of CTA is based on currently available technology. This document
  reports on the status and presents the major design concepts of CTA.

Title: Fermi Detection of a Luminous γ-Ray Pulsar in a Globular
    Cluster
Authors: Freire, P. C. C.; Abdo, A. A.; Ajello, M.; Allafort, A.;
   Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini,
   R.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.;
   Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G.;
   Cameron, R.; Camilo, F.; Caraveo, P. A.; Cecchi, C.; Çelik, Ö.;
   Charles, E.; Chekhtman, A.; Cheung, C. C.; Chiang, J.; Ciprini, S.;
   Claus, R.; Cognard, I.; Cohen-Tanugi, J.; Cominsky, L. R.; de Palma,
   F.; Dermer, C. D.; do Couto e Silva, E.; Dormody, M.; Drell, P. S.;
   Dubois, R.; Dumora, D.; Espinoza, C. M.; Favuzzi, C.; Fegan, S. J.;
   Ferrara, E. C.; Focke, W. B.; Fortin, P.; Fukazawa, Y.; Fusco, P.;
   Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giglietto,
   N.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier,
   I. A.; Grondin, M. -H.; Grove, J. E.; Guillemot, L.; Guiriec, S.;
   Hadasch, D.; Harding, A. K.; Jóhannesson, G.; Johnson, A. S.; Johnson,
   T. J.; Johnston, S.; Katagiri, H.; Kataoka, J.; Keith, M.; Kerr, M.;
   Knödlseder, J.; Kramer, M.; Kuss, M.; Lande, J.; Latronico, L.; Lee,
   S. -H.; Lemoine-Goumard, M.; Longo, F.; Loparco, F.; Lovellette, M. N.;
   Lubrano, P.; Lyne, A. G.; Manchester, R. N.; Marelli, M.; Mazziotta,
   M. N.; McEnery, J. E.; Michelson, P. F.; Mizuno, T.; Moiseev, A. A.;
   Monte, C.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia,
   S.; Nakamori, T.; Nolan, P. L.; Norris, J. P.; Nuss, E.; Ohsugi,
   T.; Okumura, A.; Omodei, N.; Orlando, E.; Ozaki, M.; Paneque, D.;
   Parent, D.; Pesce-Rollins, M.; Pierbattista, M.; Piron, F.; Porter,
   T. A.; Rainò, S.; Ransom, S. M.; Ray, P. S.; Reimer, A.; Reimer,
   O.; Reposeur, T.; Ritz, S.; Romani, R. W.; Roth, M.; Sadrozinski,
   H. F. -W.; Saz Parkinson, P. M. Sgrò, C.; Shannon, R.; Siskind,
   E. J. Smith, D. A.; Smith, P. D.; Spinelli, P.; Stappers, B. W.;
   Suson, D. J.; Takahashi, H.; Tanaka, T.; Tauris, T. M.; Thayer,
   J. B.; Theureau, G.; Thompson, D. J.; Thorsett, S. E.; Tibaldo, L.;
   Torres, D. F.; Tosti, G.; Troja, E.; Vandenbroucke, J.; Van Etten,
   A.; Vasileiou, V.; Venter, C.; Vianello, G.; Vilchez, N.; Vitale, V.;
   Waite, A. P.; Wang, P.; Wood, K. S.; Yang, Z.; Ziegler, M.; Zimmer, S.
Bibcode: 2011Sci...334.1107F
Altcode: 2011Sci...334.1107.; 2011arXiv1111.3754T
  We report on the Fermi Large Area Telescope’s detection of γ-ray
  (&gt;100 mega-electron volts) pulsations from pulsar J1823-3021A in
  the globular cluster NGC 6624 with high significance (∼7 σ). Its
  γ-ray luminosity, L<SUB>γ</SUB> = (8.4 ± 1.6) × 10<SUP>34</SUP>
  ergs per second, is the highest observed for any millisecond pulsar
  (MSP) to date, and it accounts for most of the cluster emission. The
  nondetection of the cluster in the off-pulse phase implies that it
  contains &lt;32 γ-ray MSPs, not ∼100 as previously estimated. The
  γ-ray luminosity indicates that the unusually large rate of change
  of its period is caused by its intrinsic spin-down. This implies that
  J1823-3021A has the largest magnetic field and is the youngest MSP
  ever detected and that such anomalous objects might be forming at
  rates comparable to those of the more normal MSPs.

Title: ATCA follow-up of unidentified flaring Fermi gamma-ray sources
Authors: Corbel, Stephane; Edwards, Philip; Sadler, Elaine; Thompson,
   David J.; Gehrels, Neil; Tingay, Steven; Wieringa, Mark; Grenier,
   Isabelle; Chaty, Sylvain; Dubus, Guillaume; Cameron, Robert; Abraham,
   Falcone
Bibcode: 2011atnf.prop.4337C
Altcode:
  This NAPA proposal will be triggered by the detection of a
  gamma-ray flare with the Large Area Telescope on the Fermi gamma-ray
  satellite. The Fermi team will identify bright sources flaring on
  day-timescales to trigger ATCA observations for southern sources for
  which no counterpart is known, which we expect to occur predominantly
  for sources with |b|&lt;1.5degrees. As Fermi source localizations
  are often better than 10arcmin, we will initially make simultaneous
  5GHz/9GHz observation, for which the primary beam is matched to the
  Fermi error region. If a radio counterpart can be identified, we will
  make follow-up observations at higher frequencies to help characterise
  the Spectral Energy Distribution of the source, and to monitor the
  evolution of the outburst at radio frequencies. History indicates
  this rapid localization and follow-up of flaring sources may well be
  critical in identifying a new class (or classes) of high energy object.

Title: Vortices in simulations of solar surface convection
Authors: Moll, R.; Cameron, R. H.; Schüssler, M.
Bibcode: 2011A&A...533A.126M
Altcode: 2011arXiv1108.0800M
  We report on the occurrence of small-scale vortices in simulations of
  the convective solar surface. Using an eigenanalysis of the velocity
  gradient tensor, we find the subset of high-vorticity regions in which
  the plasma is swirling. The swirling regions form an unsteady, tangled
  network of filaments in the turbulent downflow lanes. Near-surface
  vertical vortices are underdense and cause a local depression of the
  optical surface. They are potentially observable as bright points in
  the dark intergranular lanes. Vortex features typically exist for a
  few minutes, during which they are moved and twisted by the motion
  of the ambient plasma. The bigger vortices found in the simulations
  are possibly, but not necessarily, related to observations of
  granular-scale spiraling pathlines in "cork animations" or feature
  tracking. <P />Three movies are available in electronic form at <A
  href="http://www.aanda.org">http://www.aanda.org</A>

Title: Decay of a simulated mixed-polarity magnetic field in the
    solar surface layers
Authors: Cameron, R.; Vögler, A.; Schüssler, M.
Bibcode: 2011A&A...533A..86C
Altcode: 2011arXiv1108.1155C
  Magnetic flux is continuously being removed and replenished on the
  solar surface. To understand the removal process we carried out 3D
  radiative MHD simulations of the evolution of patches of photospheric
  magnetic field with equal amounts of positive and negative flux. We
  find that the flux is removed at a rate corresponding to an effective
  turbulent diffusivity, η<SUB>eff</SUB>, of 100-340 km<SUP>2</SUP>
  s<SUP>-1</SUP>, depending on the boundary conditions. For average
  unsigned flux densities above about 70 Gauss, the percentage of surface
  magnetic energy coming from different field strengths is almost
  invariant. The overall process is then one where magnetic elements
  are advected by the horizontal granular motions and occasionally come
  into contact with opposite-polarity elements. These reconnect above
  the photosphere on a comparatively short time scale after which the
  U loops produced rapidly escape through the upper surface while the
  downward retraction of inverse-U loops is significantly slower, because
  of the higher inertia and lower plasma beta in the deeper layers.

Title: Is there a non-monotonic relation between photospheric
    brightness and magnetic field strength in solar plage regions?
Authors: Röhrbein, D.; Cameron, R.; Schüssler, M.
Bibcode: 2011A&A...532A.140R
Altcode:
  Context. The relationship between the brightness and field strength
  of small-scale solar magnetic features is an important factor for
  solar irradiance variations and a constraint for simulations of solar
  magneto-convection. <BR /> Aims: We wish to clarify the origin of
  the apparent discrepancy between observational results and radiative
  MHD simulations. <BR /> Methods: Maps of (bolometric) brightness and
  magnetic field strength from the simulation of a plage region were
  convolved and rebinned to mimic observations obtained with telescopes
  with finite aperture. <BR /> Results: Image smearing changes the
  monotonic relation between brightness and field strength obtained at
  the original resolution of the simulation into a profile with a maximum
  at intermediate field strength, which is in qualitative agreement with
  the observations. This result is mainly due to the smearing of strong
  magnetic fields at the bright edges of magnetic structures into the
  weakly magnetized adjacent areas. <BR /> Conclusions: Observational
  and simulation results are qualitatively consistent with each other if
  the finite spatial resolution of the observations is taken into account.

Title: Constructing and Characterising Solar Structure Models for
    Computational Helioseismology
Authors: Schunker, H.; Cameron, R. H.; Gizon, L.; Moradi, H.
Bibcode: 2011SoPh..271....1S
Altcode: 2011SoPh..tmp..124S; 2011arXiv1105.0219S; 2011SoPh..tmp..179S;
   2011SoPh..tmp..248S
  In local helioseismology, numerical simulations of wave propagation
  are useful to model the interaction of solar waves with perturbations
  to a background solar model. However, the solution to the linearised
  equations of motion include convective modes that can swamp the
  helioseismic waves that we are interested in. In this article,
  we construct background solar models that are stable against
  convection, by modifying the vertical pressure gradient of Model S
  (Christensen-Dalsgaard et al., 1996, Science272, 1286) relinquishing
  hydrostatic equilibrium. However, the stabilisation affects the
  eigenmodes that we wish to remain as close to Model S as possible. In
  a bid to recover the Model S eigenmodes, we choose to make additional
  corrections to the sound speed of Model S before stabilisation. No
  stabilised model can be perfectly solar-like, so we present three
  stabilised models with slightly different eigenmodes. The models are
  appropriate to study the f and p<SUB>1</SUB> to p<SUB>4</SUB> modes with
  spherical harmonic degrees in the range from 400 to 900. Background
  model CSM has a modified pressure gradient for stabilisation and has
  eigenfrequencies within 2% of Model S. Model CSM_A has an additional 10%
  increase in sound speed in the top 1 Mm resulting in eigenfrequencies
  within 2% of Model S and eigenfunctions that are, in comparison with
  CSM, closest to those of Model S. Model CSM_B has a 3% decrease in
  sound speed in the top 5 Mm resulting in eigenfrequencies within 1%
  of Model S and eigenfunctions that are only marginally adversely
  affected. These models are useful to study the interaction of
  solar waves with embedded three-dimensional heterogeneities, such
  as convective flows and model sunspots. We have also calculated the
  response of the stabilised models to excitation by random near-surface
  sources, using simulations of the propagation of linear waves. We find
  that the simulated power spectra of wave motion are in good agreement
  with an observed SOHO/MDI power spectrum. Overall, our convectively
  stabilised background models provide a good basis for quantitative
  numerical local helioseismology. The models are available for download
  from http://www.mps.mpg.de/projects/seismo/NA4/.

Title: EUV jets, type III radio bursts and sunspot waves investigated
    using SDO/AIA observations
Authors: Innes, D. E.; Cameron, R. H.; Solanki, S. K.
Bibcode: 2011A&A...531L..13I
Altcode: 2011arXiv1106.3417I
  Context. Quasi-periodic plasma jets are often ejected from the Sun
  into interplanetary space. The commonly observed signatures are
  day-long sequences of type III radio bursts. <BR /> Aims: The aim is
  to identify the source of quasi-periodic jets observed on 3 Aug. 2010
  in the Sun's corona and in interplanetary space. <BR /> Methods:
  Images from the Solar Dynamics Observatory (SDO) at 211 Å are used
  to identify the solar source of the type III radio bursts seen in
  WIND/WAVES dynamic spectra. We analyse a 2.5 h period during which six
  strong bursts are seen. The radio signals are cross-correlated with
  emission from extreme ultraviolet (EUV) jets coming from the western
  side of a sunspot in AR 11092. The jets are further cross-correlated
  with brightening at a small site on the edge of the sunspot umbra,
  and the brightening with 3-min sunspot intensity oscillations. <BR />
  Results: The radio bursts correlate very well with the EUV jets. The
  EUV jet emission also correlates well with brightening at what looks
  like their footpoint at the edge of the umbra. The jet emission lags
  the radio signals and the footpoint brightening by about 30 s because
  the EUV jets take time to develop. For 10-15 min after strong EUV jets
  are ejected, the footpoint brightens at roughly 3 min intervals. In
  both the EUV images and the extracted light curves, it looks as though
  the brightening is related to the 3-min sunspot oscillations, although
  the correlation coefficient is rather low. The only open field near
  the jets is rooted in the sunspot. <BR /> Conclusions: Active region
  EUV/X-ray jets and interplanetary electron streams originate on the
  edge of the sunspot umbra. They form along a current sheet between
  the sunspot open field and closed field connecting to underlying
  satellite flux. Sunspot running penumbral waves cause roughly 3-min
  jet footpoint brightening. The relationship between the waves and
  jets is less clear. <P />Movie is available in electronic form at <A
  href="http://www.aanda.org">http://www.aanda.org</A>

Title: Universality of the Small-scale Dynamo Mechanism
Authors: Moll, R.; Pietarila Graham, J.; Pratt, J.; Cameron, R. H.;
   Müller, W. -C.; Schüssler, M.
Bibcode: 2011ApJ...736...36M
Altcode: 2011arXiv1105.0546M
  We quantify possible differences between turbulent dynamo action in
  the Sun and the dynamo action studied in idealized simulations. For
  this purpose, we compare Fourier-space shell-to-shell energy transfer
  rates of three incrementally more complex dynamo simulations: an
  incompressible, periodic simulation driven by random flow, a simulation
  of Boussinesq convection, and a simulation of fully compressible
  convection that includes physics relevant to the near-surface layers
  of the Sun. For each of the simulations studied, we find that the
  dynamo mechanism is universal in the kinematic regime because energy
  is transferred from the turbulent flow to the magnetic field from
  wavenumbers in the inertial range of the energy spectrum. The addition
  of physical effects relevant to the solar near-surface layers, including
  stratification, compressibility, partial ionization, and radiative
  energy transport, does not appear to affect the nature of the dynamo
  mechanism. The role of inertial-range shear stresses in magnetic
  field amplification is independent from outer-scale circumstances,
  including forcing and stratification. Although the shell-to-shell energy
  transfer functions have similar properties to those seen in mean-flow
  driven dynamos in each simulation studied, the saturated states of
  these simulations are not universal because the flow at the driving
  wavenumbers is a significant source of energy for the magnetic field.

Title: Universality of the Small-Scale Dynamo Mechanism
Authors: Pietarila Graham, Jonathan; Moll, R.; Pratt, J.; Cameron,
   R.; Mueller, W.; Schuessler, M.
Bibcode: 2011SPD....42.1621P
Altcode: 2011BAAS..43S.1621P
  We quantify possible differences between turbulent dynamo action in
  the Sun and the dynamo action studied in idealized simulation. For this
  purpose we compare Fourier-space shell-to-shell energy transfer rates of
  three incrementally more complex dynamo simulations: an incompressible,
  periodic simulation driven by random flow, a simulation of Boussinesq
  convection, and a simulation of fully compressible convection that
  includes physics relevant to the near-surface layers of the Sun. For
  each of the simulations studied, we find that energy is transferred
  from the turbulent flow to the magnetic field from length-scales in the
  inertial range of the energy spectrum. The addition of physical effects
  relevant to the solar near-surface layers, including stratification,
  compressibility, partial ionization, and radiative energy transport,
  does not appear to affect the nature of the dynamo mechanism. The role
  of inertial-range shear stresses in magnetic field amplification is
  independent from outer-scale circumstances, including forcing and
  stratification. Although shell-to-shell energy transfer functions
  have similar properties in each simulation studied, the saturated
  states of these simulations are not universal; the flow at the driving
  scales is a significant source of energy for the magnetic field. The
  mechanism of energy-transfer in kinematic small-scale dynamo simulations
  exhibits universal properties. <P />This work has been supported by
  the Max-Planck Society in the framework of the Interinstitutional
  Research Initiative Turbulent transport and ion heating, reconnection
  and electron acceleration in solar and fusion plasmas&lt;/u&gt; of the
  MPI for Solar System Research, Katlenburg-Lindau, and the Institute
  for Plasma Physics, Garching (project MIF-IF-A-AERO8047).

Title: SLiM: A Code for the Simulation of Wave Propagation through
    an Inhomogeneous, Magnetised Solar Atmosphere
Authors: Cameron, R.; Gizon, L.; Daiffallah, K.
Bibcode: 2011ascl.soft05004C
Altcode:
  The semi-spectral linear MHD (SLiM) code follows the interaction
  of linear waves through an inhomogeneous three-dimensional solar
  atmosphere. The background model allows almost arbitrary perturbations
  of density, temperature, sound speed as well as magnetic and velocity
  fields. The code is useful in understanding the helioseismic signatures
  of various solar features, including sunspots.

Title: The solar magnetic field since 1700. II. Physical
    reconstruction of total, polar and open flux
Authors: Jiang, J.; Cameron, R. H.; Schmitt, D.; Schüssler, M.
Bibcode: 2011A&A...528A..83J
Altcode: 2011arXiv1102.1270J
  We have used semi-synthetic records of emerging sunspot groups based
  on sunspot number data as input for a surface flux transport model to
  reconstruct the evolution of the large-scale solar magnetic field and
  the open heliospheric flux from the year 1700 onward. The statistical
  properties of the semi-synthetic sunspot group records reflect
  those of the observed Royal Greenwich Observatory photoheliographic
  results. These include correlations between the sunspot numbers
  and sunspot group latitudes, longitudes, areas and tilt angles. The
  reconstruction results for the total surface flux, the polar field,
  and the heliospheric open flux (determined by a current sheet source
  surface extrapolation) agree well with the available observational or
  empirically derived data and reconstructions. We confirm a significant
  positive correlation between the polar field during activity minimum
  periods and the strength of the subsequent sunspot cycle, which has
  implications for flux transport dynamo models for the solar cycle. Just
  prior to the Dalton minimum, at the end of the 18th century, a long
  cycle was followed by a weak cycle. We find that introducing a possibly
  "lost" cycle between 1793 and 1800 leads to a shift of the minimum of
  the open flux by 15 years which is inconsistent with the cosmogenic
  isotope record.

Title: The solar magnetic field since 1700. I. Characteristics of
    sunspot group emergence and reconstruction of the butterfly diagram
Authors: Jiang, J.; Cameron, R. H.; Schmitt, D.; Schüssler, M.
Bibcode: 2011A&A...528A..82J
Altcode: 2011arXiv1102.1266J
  We use the historic record of sunspot groups compiled by the Royal
  Greenwich Observatory together with the sunspot number to derive
  the dependence of the statistical properties of sunspot emergence on
  the cycle phase and strength. In particular we discuss the latitude,
  longitude, area and tilt angle of sunspot groups as functions of the
  cycle strength and of time during the solar cycle. Using these empirical
  characteristics the time-latitude diagram of sunspot group emergence
  (butterfly diagram) is reconstructed from 1700 onward on the basis of
  the Wolf and group sunspot numbers. This reconstruction will be useful
  in studies of the long-term evolution of the Sun's magnetic field.

Title: ATCA follow-up of unidentified flaring Fermi gamma-ray sources
Authors: Corbel, Stephane; Edwards, Philip; Sadler, Elaine; Thompson,
   David J.; Gehrels, Neil; Tingay, Steven; Wieringa, Mark; Grenier,
   Isabelle; Chaty, Sylvain; Dubus, Guillaume; Cameron, Robert; Abraham,
   Falcone
Bibcode: 2011atnf.prop.3824C
Altcode:
  This NAPA proposal will be triggered by the detection of a
  gamma-ray flare with the Large Area Telescope on the Fermi gamma-ray
  satellite. The Fermi team will identify bright sources flaring on
  day-timescales to trigger ATCA observations for southern sources for
  which no counterpart is known, which we expect to occur predominantly
  for sources with |b|&lt;1.5degrees. As Fermi source localizations
  are often better than 10arcmin, we will initially make simultaneous
  5GHz/9GHz observation, for which the primary beam is matched to the
  Fermi error region. If a radio counterpart can be identified, we will
  make follow-up observations at higher frequencies to help characterise
  the Spectral Energy Distribution of the source, and to monitor the
  evolution of the outburst at radio frequencies. History indicates
  this rapid localization and follow-up of flaring sources may well be
  critical in identifying a new class (or classes) of high energy object.

Title: Transport of Magnetic Flux from the Canopy to the Internetwork
Authors: Pietarila, A.; Cameron, R. H.; Danilovic, S.; Solanki, S. K.
Bibcode: 2011ApJ...729..136P
Altcode: 2011arXiv1102.1397P
  Recent observations have revealed that 8% of linear polarization
  patches in the internetwork (INW) quiet Sun are fully embedded in
  downflows. These are not easily explained with the typical scenarios for
  the source of INW fields which rely on flux emergence from below. Using
  radiative MHD simulations, we explore a scenario where magnetic flux
  is transported from the magnetic canopy overlying the INW into the
  photosphere by means of downward plumes associated with convective
  overshoot. We find that if a canopy-like magnetic field is present in
  the simulation, the transport of flux from the canopy is an important
  process for seeding the photospheric layers of the INW with magnetic
  field. We propose that this mechanism is relevant for the Sun as well,
  and it could naturally explain the observed INW linear polarization
  patches entirely embedded in downflows.

Title: 3D Numerical Simulations of f-Mode Propagation Through Magnetic
    Flux Tubes
Authors: Daiffallah, K.; Abdelatif, T.; Bendib, A.; Cameron, R.;
   Gizon, L.
Bibcode: 2011SoPh..268..309D
Altcode: 2010SoPh..tmp..204D; 2010SoPh..tmp..228D; 2010arXiv1008.2531D
  Three-dimensional numerical simulations have been used to study the
  scattering of a surface-gravity wave packet by vertical magnetic-flux
  tubes, with radii from 200 km to 3 Mm, embedded in stratified polytropic
  atmosphere. The scattered wave has been found to consist primarily of
  m=0 (axisymmetric) and m=1 modes. The ratio of the amplitude of these
  two modes was found to be strongly dependent on the radius of the flux
  tube. The kink mode is the dominant mode excited in tubes with a small
  radius, while the sausage mode is dominant for large tubes. Simulations
  of this type provide a simple, efficient, and robust way to start to
  understand the seismic signature of flux tubes, which have recently
  begun to be observed.

Title: Constructing Semi-Empirical Sunspot Models for Helioseismology
Authors: Cameron, R. H.; Gizon, L.; Schunker, H.; Pietarila, A.
Bibcode: 2011SoPh..268..293C
Altcode: 2010arXiv1003.0528C; 2010SoPh..tmp..167C
  One goal of helioseismology is to determine the subsurface structure
  of sunspots. In order to do so, it is important to understand
  first the near-surface effects of sunspots on solar waves, which are
  dominant. Here we construct simplified, cylindrically-symmetric sunspot
  models that are designed to capture the magnetic and thermodynamics
  effects coming from about 500 km below the quiet-Sun τ<SUB>5000</SUB>=1
  level to the lower chromosphere. We use a combination of existing
  semi-empirical models of sunspot thermodynamic structure (density,
  temperature, pressure): the umbral model of Maltby et al. (1986,
  Astrophys. J. 306, 284) and the penumbral model of Ding and Fang (1989,
  Astron. Astrophys. 225, 204). The OPAL equation-of-state tables are used
  to derive the sound-speed profile. We smoothly merge the near-surface
  properties to the quiet-Sun values about 1 Mm below the surface. The
  umbral and penumbral radii are free parameters. The magnetic field is
  added to the thermodynamic structure, without requiring magnetostatic
  equilibrium. The vertical component of the magnetic field is assumed
  to have a Gaussian horizontal profile, with a maximum surface field
  strength fixed by surface observations. The full magnetic-field vector
  is solenoidal and determined by the on-axis vertical field, which,
  at the surface, is chosen such that the field inclination is 45° at
  the umbral - penumbral boundary. We construct a particular sunspot
  model based on SOHO/MDI observations of the sunspot in active region
  NOAA 9787. The helioseismic signature of the model sunspot is studied
  using numerical simulations of the propagation of f, p<SUB>1</SUB>,
  and p<SUB>2</SUB> wave packets. These simulations are compared
  against cross-covariances of the observed wave field. We find that
  the sunspot model gives a helioseismic signature that is similar to
  the observations.

Title: Quenching of the alpha effect in the Sun -- what observations
    are telling us
Authors: Cameron, R. H.
Bibcode: 2011ASInC...2..143C
Altcode: 2011arXiv1108.1308C
  The Babcock-Leighton type of dynamo has received recent support in
  terms of the discovery in the observational records of systematic
  cycle-to-cycle variations in the tilt angle of sunspot groups. It has
  been proposed that these variations might be the consequence of the
  observed inflow into the active region belt. Furthermore simulations
  have shown that such inflows restrict the creation of net poloidal
  flux, in effect acting to quench the alpha effect associated with the
  Coriolis force acting on rising flux tubes. In this paper we expand
  on these ideas.

Title: Small-scale dynamo in solar surface simulations
Authors: Graham, J. P.; Moll, R.; Cameron, R.; Schüssler, M.
Bibcode: 2010AGUFMNG51C..01G
Altcode:
  A magneto-convection simulation incorporating essential physical
  processes governing solar surface convection exhibits turbulent
  small-scale dynamo action. By presenting a derivation of the
  energy balance equation and transfer functions for compressible
  magnetohydrodynamics (MHD), we quantify the source of magnetic energy
  on a scale-by-scale basis. We rule out the two alternative mechanisms
  for the generation of small-scale magnetic field in the simulations:
  tangling of magnetic field lines associated with the turbulent cascade
  and Alfvenization of small-scale velocity fluctuations ("turbulent
  induction"). Instead, we find the dominant source of small-scale
  magnetic energy is stretching by inertial-range fluid motions of
  small-scale magnetic field lines against the magnetic tension force to
  produce (against Ohmic dissipation) more small-scale magnetic field. The
  scales involved become smaller with increasing Reynolds number, which
  identifies the dynamo as a small-scale turbulent dynamo. Comparisons
  are made between the details of the dynamo mechanism in compressible
  magneto-convection, Boussinesq convection, and randomly-forced
  incompressible turbulence. Net energy transfers (kinematic phase):
  work against magnetic tension (stretching) is 95% of magnetic energy
  generated; work against magnetic pressure (compression) is 5%. The
  latter is involved in the breaking down larger-scale field (25%) into
  smaller-scale field (30%) as part of the cascade. The dominant producer
  of magnetic energy is the stretching of magnetic field lines against the
  magnetic tension force (turbulent dynamo action). <P />Fluid motions
  at a scale of ~140km create magnetic energy predominately at a scale
  of ~65km. As the three wave-vectors must form a triad, the scale of
  the magnetic field being stretched must is 80+/-40km. All 3 scales
  are in the inertial range: this is turbulent small-scale dynamo.

Title: Modeling the Subsurface Structure of Sunspots
Authors: Moradi, H.; Baldner, C.; Birch, A. C.; Braun, D. C.; Cameron,
   R. H.; Duvall, T. L.; Gizon, L.; Haber, D.; Hanasoge, S. M.; Hindman,
   B. W.; Jackiewicz, J.; Khomenko, E.; Komm, R.; Rajaguru, P.; Rempel,
   M.; Roth, M.; Schlichenmaier, R.; Schunker, H.; Spruit, H. C.;
   Strassmeier, K. G.; Thompson, M. J.; Zharkov, S.
Bibcode: 2010SoPh..267....1M
Altcode: 2009arXiv0912.4982M; 2010SoPh..tmp..171M
  While sunspots are easily observed at the solar surface, determining
  their subsurface structure is not trivial. There are two main
  hypotheses for the subsurface structure of sunspots: the monolithic
  model and the cluster model. Local helioseismology is the only means
  by which we can investigate subphotospheric structure. However, as
  current linear inversion techniques do not yet allow helioseismology to
  probe the internal structure with sufficient confidence to distinguish
  between the monolith and cluster models, the development of physically
  realistic sunspot models are a priority for helioseismologists. This
  is because they are not only important indicators of the variety of
  physical effects that may influence helioseismic inferences in active
  regions, but they also enable detailed assessments of the validity of
  helioseismic interpretations through numerical forward modeling. In
  this article, we provide a critical review of the existing sunspot
  models and an overview of numerical methods employed to model wave
  propagation through model sunspots. We then carry out a helioseismic
  analysis of the sunspot in Active Region 9787 and address the serious
  inconsistencies uncovered by Gizon et al. (2009a, 2009b). We find that
  this sunspot is most probably associated with a shallow, positive
  wave-speed perturbation (unlike the traditional two-layer model)
  and that travel-time measurements are consistent with a horizontal
  outflow in the surrounding moat.

Title: Erratum: Erratum to: Helioseismology of Sunspots: A Case
    Study of NOAA Region 9787
Authors: Gizon, L.; Schunker, H.; Baldner, C. S.; Basu, S.; Birch,
   A. C.; Bogart, R. S.; Braun, D. C.; Cameron, R.; Duvall, T. L.;
   Hanasoge, S. M.; Jackiewicz, J.; Roth, M.; Stahn, T.; Thompson, M. J.;
   Zharkov, S.
Bibcode: 2010SSRv..156..257G
Altcode: 2010SSRv..tmp...99G
  No abstract at ADS

Title: ATCA follow-up of unidentified flaring Fermi gamma-ray sources
Authors: Corbel, Stephane; Edwards, Philip; Sadler, Elaine; Thompson,
   David J.; Gehrels, Neil; Tingay, Steven; Wieringa, Mark; Grenier,
   Isabelle; Chaty, Sylvain; Dubus, Guillaume; Cameron, Robert; Abraham,
   Falcone
Bibcode: 2010atnf.prop.3546C
Altcode:
  This NAPA proposal will be triggered by the detection of a
  gamma-ray flare with the Large Area Telescope on the Fermi gamma-ray
  satellite. The Fermi team will identify bright sources flaring on
  day-timescales to trigger ATCA observations for southern sources for
  which no counterpart is known, which we expect to occur predominantly
  for sources with |b|&lt;1.5degrees. As Fermi source localizations
  are often better than 10arcmin, we will initially make simultaneous
  5GHz/9GHz observation, for which the primary beam is matched to the
  Fermi error region. If a radio counterpart can be identified, we will
  make follow-up observations at higher frequencies to help characterise
  the Spectral Energy Distribution of the source, and to monitor the
  evolution of the outburst at radio frequencies. History indicates
  this rapid localization and follow-up of flaring sources may well be
  critical in identifying a new class (or classes) of high energy object.

Title: Mesogranular structure in a hydrodynamical simulation
Authors: Matloch, Ł.; Cameron, R.; Shelyag, S.; Schmitt, D.;
   Schüssler, M.
Bibcode: 2010A&A...519A..52M
Altcode: 2010arXiv1007.0387M
  <BR /> Aims: We analyse mesogranular flow patterns in
  a three-dimensional hydrodynamical simulation of solar surface
  convection in order to determine its characteristics. <BR /> Methods:
  We calculate divergence maps from horizontal velocities obtained with
  the local correlation tracking (LCT) method. Mesogranules are identified
  as patches of positive velocity divergence. We track the mesogranules
  to obtain their size and lifetime distributions. We vary the analysis
  parameters to verify if the pattern has characteristic scales. <BR />
  Results: The characteristics of the resulting flow patterns depend on
  the averaging time and length used in the analysis. <BR /> Conclusions:
  We conclude that the mesogranular patterns do not exhibit intrinsic
  length and time scales.

Title: Changes of the Solar Meridional Velocity Profile During Cycle
    23 Explained by Flows Toward the Activity Belts
Authors: Cameron, R. H.; Schüssler, M.
Bibcode: 2010ApJ...720.1030C
Altcode: 2010arXiv1007.2548C
  The solar meridional flow is an important ingredient in Babcock-Leighton
  type models of the solar dynamo. Global variations of this flow
  have been suggested to explain the variations in the amplitudes and
  lengths of the activity cycles. Recently, cycle-related variations in
  the amplitude of the P <SUP>1</SUP> <SUB>2</SUB> term in the Legendre
  decomposition of the observed meridional flow have been reported. The
  result is often interpreted in terms of an overall variation in the
  flow amplitude during the activity cycle. Using a semi-empirical model
  based upon the observed distribution of magnetic flux on the solar
  surface, we show that the reported variations of the P <SUP>1</SUP>
  <SUB>2</SUB> term can be explained by the observed localized inflows
  into the active region belts. No variation of the overall meridional
  flow amplitude is required.

Title: Surface Flux Transport Modeling for Solar Cycles 15-21:
    Effects of Cycle-Dependent Tilt Angles of Sunspot Groups
Authors: Cameron, R. H.; Jiang, J.; Schmitt, D.; Schüssler, M.
Bibcode: 2010ApJ...719..264C
Altcode: 2010arXiv1006.3061C
  We model the surface magnetic field and open flux of the Sun from
  1913 to 1986 using a surface flux transport model, which includes the
  observed cycle-to-cycle variation of sunspot group tilts. The model
  reproduces the empirically derived time evolution of the solar open
  magnetic flux and the reversal times of the polar fields. We find
  that both the polar field and the axial dipole moment resulting from
  this model around cycle minimum correlate with the strength of the
  following cycle.

Title: Saturation and time dependence of geodynamo models
Authors: Schrinner, M.; Schmitt, D.; Cameron, R.; Hoyng, P.
Bibcode: 2010GeoJI.182..675S
Altcode: 2009arXiv0909.2181S
  In this study we address the question under which conditions a
  saturated velocity field stemming from geodynamo simulations leads
  to an exponential growth of the magnetic field in a corresponding
  kinematic calculation. We perform global self-consistent geodynamo
  simulations and calculate the evolution of a kinematically advanced
  tracer field. The self-consistent velocity field enters the induction
  equation in each time step, but the tracer field does not contribute to
  the Lorentz force. This experiment has been performed by Cattaneo and
  Tobias and is closely related to the test field method by Schrinner
  et al. We find two dynamo regimes in which the tracer field either
  grows exponentially or approaches a state aligned with the actual
  self-consistent magnetic field after an initial transition period. Both
  regimes can be distinguished by the Rossby number and coincide with
  the dipolar and multipolar dynamo regimes identified by Christensen and
  Aubert. Dipolar dynamos with low Rossby number are kinematically stable
  whereas the tracer field grows exponentially in the multipolar dynamo
  regime. This difference in the saturation process for dynamos in both
  regimes comes along with differences in their time variability. Within
  our sample of 20 models, solely kinematically unstable dynamos show
  dipole reversals and large excursions. The complicated time behaviour
  of these dynamos presumably relates to the alternating growth of
  several competing dynamo modes. On the other hand, dynamos in the low
  Rossby number regime exhibit a rather simple time dependence and their
  saturation merely results in a fluctuation of the fundamental dynamo
  mode about its critical state.

Title: Sunspot group tilt angles and the strength of the solar cycle
Authors: Dasi-Espuig, M.; Solanki, S. K.; Krivova, N. A.; Cameron,
   R.; Peñuela, T.
Bibcode: 2010A&A...518A...7D
Altcode: 2010arXiv1005.1774D
  Context. It is well known that the tilt angles of active regions
  increase with their latitude (Joy's law). It has never been checked
  before, however, whether the average tilt angles change from one cycle
  to the next. Flux transport models show the importance of tilt angles
  for the reversal and build up of magnetic flux at the poles, which is in
  turn correlated to the strength of the next cycle. <BR /> Aims: Here we
  analyse time series of tilt angle measurements and look for a possible
  relationship of the tilt angles with other solar cycle parameters,
  in order to glean information on the solar dynamo and to estimate
  their potential for predicting solar activity. <BR /> Methods: We
  employed tilt angle data from Mount Wilson and Kodaikanal observatories
  covering solar cycles 15 to 21. We analyse the latitudinal distribution
  of the tilt angles (Joy's law), their variation from cycle to cycle,
  and their relationship to other solar cycle parameters, such as the
  strength (or total area covered by sunspots in a cycle), amplitude,
  and length. <BR /> Results: The two main results of our analysis
  follow. 1. We find an anti-correlation between the mean normalised
  tilt angle of a given cycle and the strength (or amplitude) of that
  cycle, with a correlation coefficient of r<SUB>c</SUB> = -0.95 (99.9%
  confidence level) and r<SUB>c</SUB> = -0.93 (99.76% confidence level)
  for Mount Wilson and Kodaikanal data, respectively. 2. The product
  of the cycle's averaged tilt angle and the strength of the same cycle
  displays a significant correlation with the strength of the next cycle
  (r<SUB>c</SUB> = 0.65 at 89% confidence level and r<SUB>c</SUB> =
  0.70 at 92% confidence level for Mount Wilson and Kodaikanal data,
  respectively). An even better correlation is obtained between the
  source term of the poloidal flux in Babcock-Leighton-type dynamos (which
  contains the tilt angle) and the amplitude of the next cycle. Further we
  confirm the linear relationship (Joy's law) between the tilt angle and
  latitude with slopes of 0.26 and 0.28 for Mount Wilson and Kodaikanal
  data, respectively. In addition, we obtain good positive correlations
  between the normalised-area-weighted tilt angle and the length of the
  following cycle, whereas the strength or the amplitude of the next cycle
  does not appear to be correlated to the tilt angles of the current cycle
  alone. <BR /> Conclusions: The results of this study indicate that,
  in combination with the cycle strength, the active region tilt angles
  play an important role in building up the polar fields at cycle minimum.

Title: Expansion of magnetic flux concentrations: a comparison of
    Hinode SOT data and models
Authors: Pietarila, A.; Cameron, R.; Solanki, S. K.
Bibcode: 2010A&A...518A..50P
Altcode: 2010arXiv1005.3405P
  Context. The expansion of network magnetic fields with height is a
  fundamental property of flux tube models. A rapid expansion is required
  to form a magnetic canopy. <BR /> Aims: We characterize the observed
  expansion properties of magnetic network elements and compare them
  with the thin flux tube and sheet approximations, as well as with
  magnetoconvection simulations. <BR /> Methods: We used data from
  the Hinode SOT NFI NaD<SUB>1</SUB> channel and spectropolarimeter to
  study the appearance of magnetic flux concentrations seen in circular
  polarization as a function of position on the solar disk. We compared
  the observations with synthetic observables from models based on the
  thin flux tube approximation and magnetoconvection simulations with two
  different upper boundary conditions for the magnetic field (potential
  and vertical). <BR /> Results: The observed circular polarization signal
  of magnetic flux concentrations changes from unipolar at disk center to
  bipolar near the limb, which implies an expanding magnetic field. The
  observed expansion agrees with expansion properties derived from the
  thin flux sheet and tube approximations. Magnetoconvection simulations
  with a potential field as the upper boundary condition for the magnetic
  field also produce bipolar features near the limb while a simulation
  with a vertical field boundary condition does not. <BR /> Conclusions:
  The near-limb apparent bipolar magnetic features seen in high-resolution
  Hinode observations can be interpreted using a simple flux sheet
  or tube model. This lends further support to the idea that magnetic
  features with vastly varying sizes have similar relative expansion
  rates. The numerical simulations presented here are less useful in
  interpreting the expansion since the diagnostics we are interested in
  are strongly influenced by the choice of the upper boundary condition
  for the magnetic field in the purely photospheric simulations.

Title: The Effect of Activity-related Meridional Flow Modulation on
    the Strength of the Solar Polar Magnetic Field
Authors: Jiang, J.; Işik, E.; Cameron, R. H.; Schmitt, D.;
   Schüssler, M.
Bibcode: 2010ApJ...717..597J
Altcode: 2010arXiv1005.5317J
  We studied the effect of the perturbation of the meridional flow in the
  activity belts detected by local helioseismology on the development and
  strength of the surface magnetic field at the polar caps. We carried
  out simulations of synthetic solar cycles with a flux transport model,
  which follows the cyclic evolution of the surface field determined
  by flux emergence and advective transport by near-surface flows. In
  each hemisphere, an axisymmetric band of latitudinal flows converging
  toward the central latitude of the activity belt was superposed
  onto the background poleward meridional flow. The overall effect of
  the flow perturbation is to reduce the latitudinal separation of the
  magnetic polarities of a bipolar magnetic region and thus diminish its
  contribution to the polar field. As a result, the polar field maximum
  reached around cycle activity minimum is weakened by the presence of
  the meridional flow perturbation. For a flow perturbation consistent
  with helioseismic observations, the polar field is reduced by about 18%
  compared to the case without inflows. If the amplitude of the flow
  perturbation depends on the cycle strength, its effect on the polar
  field provides a nonlinearity that could contribute to limiting the
  amplitude of a Babcock-Leighton type dynamo.

Title: Developing Physics-Based Procedures for Local Helioseismic
    Probing of Sunspots and Magnetic Regions
Authors: Birch, Aaron; Braun, D. C.; Crouch, A.; Rempel, M.; Fan,
   Y.; Centeno, R.; Toomre, J.; Haber, D.; Hindman, B.; Featherstone,
   N.; Duvall, T., Jr.; Jackiewicz, J.; Thompson, M.; Stein, R.; Gizon,
   L.; Cameron, R.; Saidi, Y.; Hanasoge, S.; Burston, R.; Schunker, H.;
   Moradi, H.
Bibcode: 2010AAS...21630805B
Altcode:
  We have initiated a project to test and improve the local helioseismic
  techniques of time-distance and ring-diagram analysis. Our goals are
  to develop and implement physics-based methods that will (1) enable the
  reliable determinations of subsurface flow, magnetic field, and thermal
  structure in regions of strong magnetic fields and (2) be quantitatively
  tested with realistic solar magnetoconvection simulations in the
  presence of sunspot-like magnetic fields. We are proceeding through a
  combination of improvements in local helioseismic measurements, forward
  modeling of the helioseismic wavefield, kernel computations, inversions,
  and validation through numerical simulations. As improvements over
  existing techniques are made they will be applied to the SDO/HMI
  observations. This work is funded through the the NASA Heliophysics
  Science Division through the Solar Dynamics Observatory (SDO) Science
  Center program.

Title: The solar cycle and the current solar minimum
Authors: Cameron, R.; Jiang, J.; Schmitt, D.; Schuessler, M.
Bibcode: 2010EGUGA..1215494C
Altcode:
  In this talk we discuss the evolution of the Sun's large-scale magnetic
  field, on timescales relevant to the solar cycle. This evolution can
  be modeled using the surface flux transport equations, and we will
  outline the ingredients which go into the model. Special attention
  will be paid to the term describing the emergence of new flux onto
  the solar surface. The results of the model will be compared against
  observations covering most of the twentieth century, and in particular
  we will discuss what determines the surface field during solar minima.

Title: Turbulent Small-Scale Dynamo Action in Solar Surface
    Simulations
Authors: Pietarila Graham, Jonathan; Cameron, Robert; Schüssler,
   Manfred
Bibcode: 2010ApJ...714.1606P
Altcode: 2010ApJ...714.1606G; 2010arXiv1002.2750P
  We demonstrate that a magneto-convection simulation incorporating
  essential physical processes governing solar surface convection exhibits
  turbulent small-scale dynamo action. By presenting a derivation of
  the energy balance equation and transfer functions for compressible
  magnetohydrodynamics, we quantify the source of magnetic energy on a
  scale-by-scale basis. We rule out the two alternative mechanisms for
  the generation of the small-scale magnetic field in the simulations:
  the tangling of magnetic field lines associated with the turbulent
  cascade and Alfvénization of small-scale velocity fluctuations
  ("turbulent induction"). Instead, we find that the dominant source
  of small-scale magnetic energy is stretching by inertial-range fluid
  motions of small-scale magnetic field lines against the magnetic tension
  force to produce (against Ohmic dissipation) more small-scale magnetic
  field. The scales involved become smaller with increasing Reynolds
  number, which identifies the dynamo as a small-scale turbulent dynamo.

Title: ATCA follow-up of unidentified flaring Fermi gamma-ray sources
Authors: Corbel, Stephane; Edwards, Philip; Sadler, Elaine; Burrows,
   David; Thompson, David J.; Gehrels, Neil; Tingay, Steven; Wieringa,
   Mark; Grenier, Isabelle; Chaty, Sylvain; Dubus, Guillaume; Cameron,
   Robert
Bibcode: 2010atnf.prop.3161C
Altcode:
  This NAPA proposal will be triggered by the detection of a
  gamma-ray flare with the Large Area Telescope on the Fermi gamma-ray
  satellite. The Fermi team will identify bright sources flaring on
  day-timescales to trigger ATCA observations for southern sources for
  which no counterpart is known, which we expect to occur predominantly
  for sources with |b|&lt;1.5degrees. As Fermi source localizations
  are often better than 10arcmin, we will initially make simultaneous
  5GHz/9GHz observation, for which the primary beam is matched to the
  Fermi error region. If a radio counterpart can be identified, we will
  make follow-up observations at higher frequencies to help characterise
  the Spectral Energy Distribution of the source, and to monitor the
  evolution of the outburst at radio frequencies. History indicates
  this rapid localization and follow-up of flaring sources may well be
  critical in identifying a new class (or classes) of high energy object.

Title: Convectively stabilised background solar models for local
    helioseismology
Authors: Schunker, H.; Cameron, R.; Gizon, L.
Bibcode: 2010arXiv1002.1969S
Altcode:
  In local helioseismology numerical simulations of wave propagation
  are useful to model the interaction of solar waves with perturbations
  to a background solar model. However, the solution to the equations
  of motions include convective modes that can swamp the waves we are
  interested in. For this reason, we choose to first stabilise the
  background solar model against convection by altering the vertical
  pressure gradient. Here we compare the eigenmodes of our convectively
  stabilised model with a standard solar model (Model S) and find a
  good agreement.

Title: Modeling the Sun's Open Magnetic Flux and the Heliospheric
    Current Sheet
Authors: Jiang, J.; Cameron, R.; Schmitt, D.; Schüssler, M.
Bibcode: 2010ApJ...709..301J
Altcode: 2009arXiv0912.0108J
  By coupling a solar surface flux transport model with an extrapolation
  of the heliospheric field, we simulate the evolution of the Sun's
  open magnetic flux and the heliospheric current sheet (HCS) based
  on observational data of sunspot groups since 1976. The results are
  consistent with measurements of the interplanetary magnetic field near
  Earth and with the tilt angle of the HCS as derived from extrapolation
  of the observed solar surface field. This opens the possibility for
  an improved reconstruction of the Sun's open flux and the HCS into
  the past on the basis of empirical sunspot data.

Title: Numerical Simulations of Quiet Sun Oscillations
Authors: Schunker, H.; Cameron, R.; Gizon, L.
Bibcode: 2009ASPC..416...49S
Altcode:
  We develop a quiet Sun background model to be used for the numerical
  simulation of solar oscillations and explore the properties of this
  model using the three-dimensional Semi-spectral Linear MHD (SLiM)
  code. We first suggest criteria for defining a convectively stable,
  but solar-like, background model. A first step in the development
  of such a solar-like model is presented and we demonstrate that it
  meets the first of the criteria by comparing the power spectrum of
  the simulation with SoHO/MDI observations.

Title: Expansion of Magnetic Flux Concentrations with Height:
    A Comparison of Hinode SOT Data and MHD Simulations
Authors: Pietarila, A.; Cameron, R.; Solanki, S.
Bibcode: 2009ASPC..415...91P
Altcode:
  The Hinode SOT (Tsuneta et al. 2008) NFI Na I D<SUB>1</SUB> and SP Fe I
  data sampled at different positions on the solar disk provide a unique
  diagnostic for studying the expansion of magnetic flux concentrations
  with height. We make a comparative study of SOT observations and
  2-dimensional (2D) radiative MHD-simulations to see how well the
  simulations capture the expansion properties. The expansion of flux
  concentrations is clearly seen in the SOT Na I D<SUB>1</SUB> data,
  where most of the magnetic features appear unipolar at disk center while
  close to the limb bipolar appearance strongly dominates. This trend,
  albeit not as strong, is seen in the SP data as well. Some aspects of
  the observations are qualitatively reproduced by simulations with a
  potential (as opposed to vertical) upper boundary condition for the
  magnetic field.

Title: Radiative MHD simulations of sunspot structure
Authors: Rempel, M.; Schuessler, M.; Cameron, R.; Knoelker, M.
Bibcode: 2009AGUFMSH53B..07R
Altcode:
  For a long time radiative MHD simulations of entire sunspots from
  first principles were out of reach due to insufficient computing
  resources. Over the past 4 years simulations have evolved from
  6x6x2 Mm size domains focusing on the details of umbral dots to
  simulations covering a pair of opposite polarity sunspots in a
  100x50x6 Mm domain. Numerical simulations point toward a common magneto
  convective origin of umbral dots and filaments in the inner and outer
  penumbra. Most recent simulations also capture the processes involved
  in the formation of an extended outer penumbra with strong horizontal
  outflows averaging around 5 km/s in the photosphere. In this talk I
  will briefly review the progress made in this field over the past 4
  years and discuss in detail the magneto convective origin of penumbral
  fine structure as well as the Evershed flow.

Title: Solar surface magnetoconvection simulations: A brief review
    of solar dermatology
Authors: Cameron, Robert
Bibcode: 2009ScChG..52.1665C
Altcode:
  Rapid improvement in the speed of computers has enabled realistic
  simulations of magnetoconvective processes in the surface layers of
  the Sun. The simulations now cover a wide range of features found in
  observations. In many cases a direct comparison with the observations
  is justified, and in all cases our understanding and interpretation of
  the observations is being improved. Current and future opportunities
  and difficulties will be discussed.

Title: ATCA follow-up of unidentified flaring Fermi gamma-ray sources
Authors: Corbel, Stephane; Edwards, Philip; Sadler, Elaine; Burrows,
   David; Thompson, David J.; Gehrels, Neil; Tingay, Steven; Wieringa,
   Mark; Grenier, Isabelle; Chaty, Sylvain; Dubus, Guillaume; Cameron,
   Robert
Bibcode: 2009atnf.prop.2654C
Altcode:
  This NAPA proposal will be triggered by the detection of a
  gamma-ray flare with the Large Area Telescope on the Fermi gamma-ray
  satellite. The Fermi team will identify bright sources flaring on
  day-timescales to trigger ATCA observations for southern sources for
  which no counterpart is known, which we expect to occur predominantly
  for sources with |b|&lt;1.5degrees. As Fermi source localizations
  are often better than 10arcmin, we will initially make simultaneous
  5GHz/9GHz observation, for which the primary beam is matched to the
  Fermi error region. If a radio counterpart can be identified, we will
  make follow-up observations at higher frequencies to help characterise
  the Spectral Energy Distribution of the source, and to monitor the
  evolution of the outburst at radio frequencies. History indicates
  this rapid localization and follow-up of flaring sources may well be
  critical in identifying a new class (or classes) of high energy object.

Title: Radiative MHD simulations of sunspot structure
Authors: Rempel, M.; Schüssler, M.; Cameron, R.; Knölker, M.
Bibcode: 2009iac..talk..192R
Altcode: 2009iac..talk..106R
  No abstract at ADS

Title: Modelling of solar mesogranulation
Authors: Matloch, L.; Cameron, R.; Schmitt, D.; Schüssler, M.
Bibcode: 2009A&A...504.1041M
Altcode:
  We study whether mesogranulation flow patterns at the solar surface
  can arise solely from the statistical properties of granules and
  intergranular lanes. We have developed one- and two-dimensional models
  with local interaction rules between the artificial “granules”
  mimicking the actual physical processes on the solar surface. Defining
  mesogranulation according to the age of intergranular (downflow) lanes
  corresponding to the often applied “cork method”, as well as the
  areas of divergence of the horizontal velocity (two-dimensional model),
  we find that mesogranular patterns are present in our models. Our study
  of the dependence of the properties of the mesogranular patterns on
  the model parameter and interaction rules reveals that the patterns
  do not possess intrinsic length and time scales. <P />Appendix is only
  available in electronic from at http://www.aanda.org

Title: Penumbral Structure and Outflows in Simulated Sunspots
Authors: Rempel, M.; Schüssler, M.; Cameron, R. H.; Knölker, M.
Bibcode: 2009Sci...325..171R
Altcode: 2009arXiv0907.2259R
  Sunspots are concentrations of magnetic field on the visible solar
  surface that strongly affect the convective energy transport in their
  interior and surroundings. The filamentary outer regions (penumbrae)
  of sunspots show systematic radial outward flows along channels of
  nearly horizontal magnetic field. These flows were discovered 100
  years ago and are present in all fully developed sunspots. By using
  a comprehensive numerical simulation of a sunspot pair, we show
  that penumbral structures with such outflows form when the average
  magnetic field inclination to the vertical exceeds about 45 degrees. The
  systematic outflows are a component of the convective flows that provide
  the upward energy transport and result from anisotropy introduced by
  the presence of the inclined magnetic field.

Title: ATCA follow-up of unidentified flaring Fermi gamma-ray sources
Authors: Corbel, Stephane; Edwards, Philip; Sadler, Elaine; Burrows,
   David; Thompson, David J.; Gehrels, Neil; Tingay, Steven; Wieringa,
   Mark; Grenier, Isabelle; Chaty, Sylvain; Dubus, Guillaume; Cameron,
   Robert
Bibcode: 2009atnf.prop.2459C
Altcode:
  This NAPA proposal will be triggered by the detection of a
  gamma-ray flare with the Large Area Telescope on the Fermi gamma-ray
  satellite. The Fermi team will identify bright sources flaring on
  day-timescales to trigger ATCA observations for southern sources for
  which no counterpart is known, which we expect to occur predominantly
  for sources with |b|&lt;1.5degrees. As Fermi source localizations
  are often better than 10arcmin, we will initially make simultaneous
  5GHz/9GHz observation, for which the primary beam is matched to the
  Fermi error region. If a radio counterpart can be identified, we will
  make follow-up observations at higher frequencies to help characterise
  the Spectral Energy Distribution of the source, and to monitor the
  evolution of the outburst at radio frequencies. History indicates
  this rapid localization and follow-up of flaring sources may well be
  critical in identifying a new class (or classes) of high energy object.

Title: Radiative MHD Simulations of Sunspot Structure
Authors: Rempel, Matthias D.; Schuessler, M.; Cameron, R.; Knoelker, M.
Bibcode: 2009SPD....40.0604R
Altcode:
  We summarize the recent progress made in magneto convection simulations
  of sunspot structure. Over the past 4 years simulations have evolved
  from local 6x6x2 Mm size domains focusing on the details of umbral
  dots to simulations covering a pair of opposite polarity spots in
  a 100x50x6 Mm domain. The simulations point out the common magneto
  convective origin of umbral dots and filaments in the inner penumbra
  and most recently also reveal the processes involved in the formation
  of an extended outer penumbra with strong horizontal outflows averaging
  around 5 km/s in the photosphere.

Title: Helioseismology of Sunspots: A Case Study of NOAA Region 9787
Authors: Gizon, L.; Schunker, H.; Baldner, C. S.; Basu, S.; Birch,
   A. C.; Bogart, R. S.; Braun, D. C.; Cameron, R.; Duvall, T. L.;
   Hanasoge, S. M.; Jackiewicz, J.; Roth, M.; Stahn, T.; Thompson, M. J.;
   Zharkov, S.
Bibcode: 2009SSRv..144..249G
Altcode: 2008SSRv..tmp..188G; 2010arXiv1002.2369G
  Various methods of helioseismology are used to study the subsurface
  properties of the sunspot in NOAA Active Region 9787. This sunspot
  was chosen because it is axisymmetric, shows little evolution during
  20-28 January 2002, and was observed continuously by the MDI/SOHO
  instrument. AR 9787 is visible on helioseismic maps of the farside
  of the Sun from 15 January, i.e. days before it crossed the East
  limb. Oscillations have reduced amplitudes in the sunspot at all
  frequencies, whereas a region of enhanced acoustic power above 5.5 mHz
  (above the quiet-Sun acoustic cutoff) is seen outside the sunspot and
  the plage region. This enhanced acoustic power has been suggested to
  be caused by the conversion of acoustic waves into magneto-acoustic
  waves that are refracted back into the interior and re-emerge as
  acoustic waves in the quiet Sun. Observations show that the sunspot
  absorbs a significant fraction of the incoming p and f modes around 3
  mHz. A numerical simulation of MHD wave propagation through a simple
  model of AR 9787 confirmed that wave absorption is likely to be due
  to the partial conversion of incoming waves into magneto-acoustic
  waves that propagate down the sunspot. Wave travel times and mode
  frequencies are affected by the sunspot. In most cases, wave packets
  that propagate through the sunspot have reduced travel times. At
  short travel distances, however, the sign of the travel-time shifts
  appears to depend sensitively on how the data are processed and,
  in particular, on filtering in frequency-wavenumber space. We carry
  out two linear inversions for wave speed: one using travel-times
  and phase-speed filters and the other one using mode frequencies
  from ring analysis. These two inversions give subsurface wave-speed
  profiles with opposite signs and different amplitudes. The travel-time
  measurements also imply different subsurface flow patterns in the
  surface layer depending on the filtering procedure that is used. Current
  sensitivity kernels are unable to reconcile these measurements, perhaps
  because they rely on imperfect models of the power spectrum of solar
  oscillations. We present a linear inversion for flows of ridge-filtered
  travel times. This inversion shows a horizontal outflow in the upper
  4 Mm that is consistent with the moat flow deduced from the surface
  motion of moving magnetic features. From this study of AR 9787, we
  conclude that we are currently unable to provide a unified description
  of the subsurface structure and dynamics of the sunspot.

Title: ATCA monitoring of gamma-ray loud AGN in support of the
    Fermi mission
Authors: Tingay, Steven; Macquart, Jean-Pierre; Lovell, Jim; Edwards,
   Philip; Sadler, Elaine; Ojha, Roopesh; Romani, Roger W.; Kadler,
   Matthias; Murphy, David; Gehrels, Neil; Michelson, Peter; Cameron,
   Robert
Bibcode: 2009atnf.prop.1995T
Altcode:
  Following a successful pilot investigation to determine the feasibility
  of monitoring bright gamma-ray AGN at 7 mm throughout the year (C1730),
  we propose a continuation of the project into a one year phase of
  observations that will support the Fermi mission following its June 2008
  launch. The goal of this project is to monitor Fermi-identified AGN
  at 4.8, 8.6, 17, 19, 38, and 40 GHz at monthly intervals, tracking
  variability in the AGN (in particular flaring activity) that can
  be related to gamma-ray variability observed by Fermi and pc-scale
  structural variability observed by our concurrent Southern Hemipshere
  VLBI monitoring program in support of Fermi. The ATCA, VLBI, and Fermi
  data will contribute to a multi-wavelength AGN database that will help
  us understand the origins of high energy emission in AGN.

Title: ATCA follow-up of unidentified flaring Fermi gamma-ray sources
Authors: Edwards, Philip; Sadler, Elaine; Romani, Roger W.; Tingay,
   Steven; Wieringa, Mark; Michelson, Peter; Cameron, Robert
Bibcode: 2009atnf.prop.2222E
Altcode:
  This NAPA proposal will be triggered by the detection of a
  gamma-ray flare with the Large Area Telescope on the Fermi gamma-ray
  satellite. The Fermi team will identify bright sources flaring on
  day-timescales to trigger ATCA observations for southern sources for
  which no counterpart is known, which we expect to occur predominantly
  for sources with |b|&lt;1.5degrees. As Fermi source localizations
  are often better than 10arcmin, we will initially make simultaneous
  5GHz/9GHz observation, for which the primary beam is matched to the
  Fermi error region. If a radio counterpart can be identified, we will
  make follow-up observations at higher frequencies to help characterise
  the Spectral Energy Distribution of the source, and to monitor the
  evolution of the outburst at radio frequencies. History indicates
  this rapid localization and follow-up of flaring sources may well be
  critical in identifying a new class (or classes) of high energy object.

Title: Countercell Meridional Flow and Latitudinal Distribution of
    the Solar Polar Magnetic Field
Authors: Jiang, J.; Cameron, R.; Schmitt, D.; Schüssler, M.
Bibcode: 2009ApJ...693L..96J
Altcode:
  Recent observations indicate that the latitudinal profile of the
  magnetic flux shows a pronounced decrease close to the solar north
  pole during the minimum phase of solar cycle 23. Using a surface flux
  transport model, we have performed numerical experiments to study the
  conditions that could lead to such a latitudinal distribution. We find
  that a strong decrease of the magnetic field near the poles results
  if a weak countercell of the meridional flow at high latitudes with
  an equatorward speed of a few m s<SUP>-1</SUP> is present.

Title: Surface-Focused Seismic Holography of Sunspots:
    II. Expectations from Numerical Simulations Using Sound-Speed
    Perturbations
Authors: Birch, A. C.; Braun, D. C.; Hanasoge, S. M.; Cameron, R.
Bibcode: 2009SoPh..254...17B
Altcode: 2008SoPh..tmp..186B
  Helioseismic observations of sunspots show that wave travel times, at
  fixed horizontal phase speed, depend on the temporal frequency of the
  waves employed in the data analysis. This frequency variation has been
  suggested to be consistent with near-surface (vertical length scales
  of order one Mm or smaller) changes in wave propagation properties
  relative to the quiet Sun. We investigate this suggestion by employing
  numerical simulations of acoustic-wave propagation through models
  with horizontally and vertically inhomogeneous structure. Standard
  methods of surface-focused helioseismic holography are applied to the
  resulting simulated wave fields. We find that the travel-time shifts
  measured using holography from the simulations with deep sound-speed
  perturbations (relative to a plane-parallel quiet-Sun model) do not
  show a systematic frequency dependence at phase speeds above about
  20 km s<SUP>−1</SUP>. However, shallow sound-speed perturbations,
  similar to those proposed to model the acoustic scattering properties
  of sunspots observed with Hankel analysis, produce systematic frequency
  dependence at these phase speeds. In both cases, positive travel-time
  shifts can be caused by positive sound-speed perturbations. The details
  of the travel-time shifts are, however, model dependent.

Title: Helioseismology of Sunspots: A Case Study of NOAA Region 9787
Authors: Gizon, L.; Schunker, H.; Baldner, C. S.; Basu, S.; Birch,
   A. C.; Bogart, R. S.; Braun, D. C.; Cameron, R.; Duvall, T. L.;
   Hanasoge, S. M.; Jackiewicz, J.; Roth, M.; Stahn, T.; Thompson, M. J.;
   Zharkov, S.
Bibcode: 2009odsm.book..249G
Altcode:
  Various methods of helioseismology are used to study the subsurface
  properties of the sunspot in NOAA Active Region 9787. This sunspot
  was chosen because it is axisymmetric, shows little evolution during
  20-28 January 2002, and was observed continuously by the MDI/SOHO
  instrument. AR 9787 is visible on helioseismic maps of the farside of
  the Sun from 15 January, i.e. days before it crossed the East limb.

Title: A Robust Correlation between Growth Rate and Amplitude of
Solar Cycles: Consequences for Prediction Methods
Authors: Cameron, R.; Schüssler, M.
Bibcode: 2008ApJ...685.1291C
Altcode:
  We consider the statistical relationship between the growth rate
  of activity in the early phase of a solar cycle with its subsequent
  amplitude on the basis of four data sets of global activity indices
  (Wolf sunspot number, group sunspot number, sunspot area, and 10.7 cm
  radio flux). In all cases, a significant correlation is found: stronger
  cycles tend to rise faster. Owing to the overlapping of sunspot cycles,
  this correlation leads to an amplitude-dependent shift of the solar
  minimum epoch. We show that this effect explains the correlations
  underlying various so-called precursor methods for the prediction
  of solar cycle amplitudes and also affects the prediction tool of
  Dikpati et al. based on a dynamo model. Inferences as to the nature
  of the solar dynamo mechanism resulting from predictive schemes which
  (directly or indirectly) use the timing of solar minima should therefore
  be treated with caution.

Title: Helioseismology of Sunspots: Confronting Observations with
    Three-Dimensional MHD Simulations of Wave Propagation
Authors: Cameron, R.; Gizon, L.; Duvall, T. L., Jr.
Bibcode: 2008SoPh..251..291C
Altcode: 2008arXiv0802.1603C; 2008SoPh..tmp...51C
  The propagation of solar waves through the sunspot of AR 9787
  is observed by using temporal cross-correlations of SOHO/MDI
  Dopplergrams. We then use three-dimensional MHD numerical simulations
  to compute the propagation of wave packets through self-similar
  magnetohydrostatic sunspot models. The simulations are set up in
  such a way as to allow a comparison with observed cross-covariances
  (except in the immediate vicinity of the sunspot). We find that the
  simulation and the f-mode observations are in good agreement when the
  model sunspot has a peak field strength of 3 kG at the photosphere
  and less so for lower field strengths. Constraining the sunspot model
  with helioseismology is only possible because the direct effect of
  the magnetic field on the waves has been fully taken into account. Our
  work shows that the full-waveform modeling of sunspots is feasible.

Title: The seismic effects of a sunspot
Authors: Schunker, H.; Cameron, R.; Gizon, L.
Bibcode: 2008ESPM...12..3.5S
Altcode:
  We simulate the helioseismic wave field by using the three-dimensional
  Semi-spectral Linear MHD (SLiM) code and exciting small-amplitude waves
  by sources distributed in the near-surface layers of a model solar
  atmosphere.Our model atmosphere is realistic in the sense that it has
  a standard sound-speed profile. Our source function is a realization
  drawn from a random process specified by a statistical description of
  solar convection. We obtain a quiet-Sun power spectrum of wave motions,
  which is consistent with Doppler observations. In order to study wave
  propagation through sunspots, we derive a simplified monolithic model
  sunspot embedded in the quiet-Sun model atmosphere. The corresponding
  wave field computed with SLiM is then compared with MDI observations
  of f- and p-mode scattering by magnetic region AR9787. The comparison
  is encouraging as the numerical simulation is able to reproduce wave
  absorption and scattering phase shifts. As part of our analysis, we
  show the advantage of computing a reference quiet-Sun wave field using
  the same realization of the sources for the purpose of comparisons
  and noise reduction.

Title: Radiative magnetohydrodynamic simulations of solar pores
Authors: Cameron, R.; Schüssler, M.; Vögler, A.; Zakharov, V.
Bibcode: 2007A&A...474..261C
Altcode:
  Context: Solar pores represent a class of magnetic structures
  intermediate between small-scale magnetic flux concentrations in
  intergranular lanes and fully developed sunspots with penumbrae. <BR
  />Aims: We study the structure, energetics, and internal dynamics
  of pore-like magnetic structures by means of exploratory numerical
  simulations. <BR />Methods: The MURaM code has been used to carry
  out several 3D radiative MHD simulations for pores of various sizes
  and with different boundary conditions. <BR />Results: The general
  properties of the simulated pores (morphology, continuum intensity,
  magnetic field geometry, surrounding flow pattern, mean height
  profiles of temperature, pressure, and density) are consistent with
  observational results. No indications for the formation of penumbral
  structure are found. The simulated pores decay by gradually shedding
  magnetic flux into the surrounding pattern of intergranular downflows
  (“turbulent erosion”). When viewed under an angle (corresponding
  to observations outside solar disc center), granules behind the pore
  appear brightened. <BR />Conclusions: Radiative MHD simulations capture
  many observed properties of solar pores.

Title: Photospheric magnetoconvection
Authors: Cameron, Robert; Vögler, Alexander; Schüssler, Manfred
Bibcode: 2007IAUS..239..475C
Altcode:
  No abstract at ADS

Title: Solar Cycle Prediction Using Precursors and Flux Transport
    Models
Authors: Cameron, R.; Schüssler, M.
Bibcode: 2007ApJ...659..801C
Altcode: 2006astro.ph.12693C
  We study the origin of the predictive skill of some methods to
  forecast the strength of solar activity cycles. A simple flux
  transport model for the azimuthally averaged radial magnetic field at
  the solar surface is used, which contains a source term describing
  the emergence of new flux based on observational sunspot data. We
  consider the magnetic flux diffusing over the equator as a predictor,
  since this quantity is directly related to the global dipole field from
  which a Babcock-Leighton dynamo generates the toroidal field for the
  next activity cycle. If the source is represented schematically by a
  narrow activity belt drifting with constant speed over a fixed range
  of latitudes between activity minima, our predictor shows considerable
  predictive skill, with correlation coefficients up to 0.95 for past
  cycles. However, the predictive skill is completely lost when the
  actually observed emergence latitudes are used. This result originates
  from the fact that the precursor amplitude is determined by the sunspot
  activity a few years before solar minimum. Since stronger cycles tend to
  rise faster to their maximum activity (known as the Waldmeier effect),
  the temporal overlapping of cycles leads to a shift of the minimum
  epochs that depends on the strength of the following cycle. This
  information is picked up by precursor methods and also by our flux
  transport model with a schematic source. Therefore, their predictive
  skill does not require a memory, i.e., a physical connection between
  the surface manifestations of subsequent activity cycles.

Title: SLiM: a code for the simulation of wave propagation through
    an inhomogeneous, magnetised solar atmosphere
Authors: Cameron, R.; Gizon, L.; Daiffallah, K.
Bibcode: 2007AN....328..313C
Altcode: 2010arXiv1002.2344C
  In this paper we describe the semi-spectral linear MHD (SLiM) code
  which we have written to follow the interaction of linear waves through
  an inhomogeneous three-dimensional solar atmosphere. The background
  model allows almost arbitrary perturbations of density, temperature,
  sound speed as well as magnetic and velocity fields. We give details of
  several of the tests we have used to check the code. The code will be
  useful in understanding the helioseismic signatures of various solar
  features, including sunspots.

Title: Solar mesogranulation as a cellular automaton effect
Authors: Matloch, L.; Cameron, R.; Schmitt, D.; Schüssler, M.
Bibcode: 2007msfa.conf..339M
Altcode:
  We present a simple cellular automaton model of solar granulation
  that captures the granular cell characteristics in terms of lifetime
  and size distributions. We show that mesogranulation, as defined in
  observational data, is an intrinsic feature of such a cell system.

Title: Helioseismology at MPS
Authors: Gizon, L.; Cameron, R.; Jackiewicz, J.; Roth, M.; Schunker,
   H.; Stahn, T.
Bibcode: 2007msfa.conf...89G
Altcode:
  Research in solar and stellar seismology at the Max Planck Institute
  for Solar System Research (MPS) is supported by the Junior Research
  Group "Helio- and Asteroseismology" of the Max Planck Society since
  September 2005. A presentation of the current topics of research is
  given, with particular emphasis on local helioseismology.

Title: Three-dimensional numerical simulation of wave propagation
    through a model sunspot
Authors: Cameron, R.; Gizon, L.
Bibcode: 2006ESASP.624E..63C
Altcode: 2006soho...18E..63C
  No abstract at ADS

Title: ChaMP Serendipitous Galaxy Cluster Survey
Authors: Barkhouse, W. A.; Green, P. J.; Vikhlinin, A.; Kim, D. -W.;
   Perley, D.; Cameron, R.; Silverman, J.; Mossman, A.; Burenin, R.;
   Jannuzi, B. T.; Kim, M.; Smith, M. G.; Smith, R. C.; Tananbaum, H.;
   Wilkes, B. J.
Bibcode: 2006ApJ...645..955B
Altcode: 2006astro.ph..3521B
  We present a survey of serendipitous extended X-ray sources and optical
  cluster candidates from the Chandra Multiwavelength Project (ChaMP). Our
  main goal is to make an unbiased comparison of X-ray and optical
  cluster detection methods. In 130 archival Chandra pointings covering
  13 deg<SUP>2</SUP>, we use a wavelet decomposition technique to detect
  55 extended sources, of which 6 are nearby single galaxies. Our X-ray
  cluster catalog reaches a typical flux limit of about ~10<SUP>-14</SUP>
  ergs cm<SUP>-2</SUP> s<SUP>-1</SUP>, with a median cluster core radius
  of 21<SUP>''</SUP>. For 56 of the 130 X-ray fields, we use the ChaMP's
  deep NOAO 4 m MOSAIC g<SUP>'</SUP>, r<SUP>'</SUP>, and i<SUP>'</SUP>
  imaging to independently detect cluster candidates using a Voronoi
  tessellation and percolation (VTP) method. Red-sequence filtering
  decreases the galaxy fore- and background contamination and provides
  photometric redshifts to z~0.7. From the overlapping 6.1 deg<SUP>2</SUP>
  X-ray/optical imaging, we find 115 optical clusters (of which 11%
  are in the X-ray catalog) and 28 X-ray clusters (of which 46% are in
  the optical VTP catalog). The median redshift of the 13 X-ray/optical
  clusters is 0.41, and their median X-ray luminosity (0.5-2 keV) is
  L<SUB>X</SUB>=(2.65+/-0.19)×10<SUP>43</SUP> ergs s<SUP>-1</SUP>. The
  clusters in our sample that are only detected in our optical data are
  poorer on average (~4 σ) than the X-ray/optically matched clusters,
  which may partially explain the difference in the detection fractions.

Title: High field strength modified ABC and rotor dynamos
Authors: Cameron, Robert; Galloway, David
Bibcode: 2006MNRAS.367.1163C
Altcode: 2006MNRAS.tmp..233C
  The Archontis dynamo was the first stationary dynamo discovered
  which saturates with almost equal magnetic and kinetic energies in
  the limit of large Reynolds numbers. In this paper we present two
  further examples, one based on a series of numerical calculations and
  the other on the analytic rotor dynamos of Herzenberg. The forcing and
  flow in these new examples lack some of the symmetries of the Archontis
  dynamo are therefore more generic. The saturation mechanism is thus
  not a unique property of the Archontis dynamo. <P />For the numerical
  solutions, we also have investigated the structure and stability of
  the flow and field near the stagnation points and those streamlines
  which enter and leave them. These structures play an important part
  in the operation of the dynamo mechanism, and the way they interact
  with one another is mirrored in the analytic example based on the
  Herzenberg rotors.

Title: Extending the X-ray Luminosity Function of AGN to High Redshift
Authors: Silverman, J.; Green, P.; Barkhouse, W.; Cameron, R.; Kim,
   M.; Kim, D. -W.; Wilkes, B.; Hasinger, G.; Full Champ Project, The
Bibcode: 2006ESASP.604..795S
Altcode: 2005astro.ph.11552S; 2006xru..conf..795S
  X-ray surveys of the extragalactic universe are now able to detect
  significant numbers of AGN out to high redshift (z~5). We highlight some
  results from the Chandra Multiwavelength Project (ChaMP) to measure
  the X-ray luminosity function out to these early epochs. At z &gt; 3,
  we show that the comoving space density of luminous (log Lx &gt; 44.5)
  AGN has a behavior similar to the optical QSO luminosity function. With
  a newly compiled sample of AGN from ChaMP supplemented with those from
  additional surveys including the Chandra Deep fields, we present a
  preliminary measure of the luminosity function in the hard (2-8 keV)
  band. With 37 AGN at z &gt; 3, we continue to see a decline in the
  space density at high redshift over a wider range in luminosity. We
  discuss the need to identify a larger sample of obscured AGN at high
  redshift to determine if an early epoch of hidden supermassive black
  hole growth occurred.

Title: Saturation properties of the Archontis dynamo
Authors: Cameron, Robert; Galloway, David
Bibcode: 2006MNRAS.365..735C
Altcode: 2005MNRAS.tmp.1100C
  This paper discusses the generation and subsequent non-linear limiting
  of magnetic fields by motions in a periodic flow driven by a force
  whose components are proportional to (sinz, sinx, siny). This problem
  was originally studied by Archontis; the purpose of the present work
  is to remove certain complications present in the original model in
  order to understand better the underlying physical mechanism which
  limits the total magnetic energy growth. At high Reynolds numbers the
  resulting dynamos end up with almost equal total magnetic and kinetic
  energies, and thus yield fields strong enough to be astrophysically
  relevant. Until now, the existence of such dynamos has been doubted,
  so this demonstration of an example appears very important. At
  least up to Reynolds numbers of 800, these solutions are laminar
  and attracting. <P />We then present an argument showing that any
  stationary, incompressible dynamo can be used to create a family of
  solutions with an arbitrary ratio of magnetic to kinetic energies in
  the limit of large Reynolds numbers. The stability of such solutions
  is also discussed.

Title: Simulations of Solar Pores
Authors: Cameron, R.; Vögler, A.; Schüssler, M.; Zakharov, V.
Bibcode: 2005ESASP.600E..11C
Altcode: 2005ESPM...11...11C; 2005dysu.confE..11C
  No abstract at ADS

Title: The structure of small-scale magnetic flux tubes
Authors: Cameron, Robert; Galloway, David
Bibcode: 2005MNRAS.358.1025C
Altcode: 2005MNRAS.tmp..199C
  Three main mechanisms have been described to determine the maximum
  field strength and structure of a solar or stellar magnetic flux
  tube. This paper attempts to relate them to one another through a
  series of magnetoconvective calculations. The first process is the
  balancing of the Lorentz force by radial gradients in the buoyancy
  force. It was first found in the Boussinesq regime, where it was
  studied in the late 1970s by Galloway, Proctor &amp; Weiss. A similar
  balance can occur in the fully compressible case, where we refer to it
  as quasi-Boussinesq (QB). The second process involves a balance between
  an outward-directed radial pressure gradient and radial gradients in the
  buoyancy force outside the tube. This is the mechanism proposed in the
  early 1990s by Kerswell &amp; Childress (the KC mechanism). The third
  mechanism, convective collapse (CC), is a process whereby a flux tube
  can evolve to a high field strength because of an instability due to
  the superadiabaticity of the material within the tube. Until now, it
  has been studied using the so-called `thin flux tube' approximation in
  which convective motions are ignored even though there is a background
  superadiabatic density stratification. Here we place these three
  mechanisms in a unified framework and explore the transitions between
  the solutions as various parameters are varied. In particular, we show
  that the QB solutions are preferred for a wide range of parameters,
  whereas CC solutions occur only in very specific circumstances. In
  particular, on the Sun, the latter are probably limited to flux tubes
  with radii less than approximately 10 km, the turbulent magnetic
  diffusivity length-scale.

Title: The Decay of a Simulated Pore
Authors: Cameron, R.; Vögler, A.; Shelyag, S.; Schüssler, M.
Bibcode: 2004ASPC..325...57C
Altcode:
  Using MURaM -- Max-Planck Institut für Aeronomie University of
  Chicago Radiative Magnetohydrodynamics -- an MHD code which includes
  radiative transfer and partial ionization, we have studied the decay
  phase of a solar pore. The simulations are sufficiently realistic
  in their treatment of the photosphere to allow a direct comparison
  with observations, both current and those of upcoming missions such
  as SolarB. As well as discussing the structure and decay of pores,
  we show the formation of shallow, field aligned, convective rolls
  which are an important feature of our solutions.

Title: Finding the Obscured AGN with ChAMP
Authors: Aldcroft, T.; Green, P.; Silverman, J.; Cameron, R.; Kim,
   D.; Wilkes, B.; ChaMP Collaboration
Bibcode: 2004HEAD....8.3506A
Altcode: 2004BAAS...36..973A
  X-ray surveys with \textit{Chandra} and \textit{XMM} provide the most
  complete census of accretion powered luminosity in the universe. Coupled
  with recent advances suggesting an intimate connection between galaxy
  and supermassive black hole evolution, X-ray AGN surveys have emerged as
  a powerful tool for investigating topics from galaxies to large scale
  cosmology. One empirical input which plays a key role in modeling is
  the distribution of obscuration in AGN. Obscuration changes the AGN
  spectral contribution to the hard Cosmic X-ray Background (CXRB), the
  apparent luminosity of AGN, and can even make them entirely "disappear",
  so understanding this phenomenon is important. Using X-ray and optical
  imaging and spectroscopic data from the \textit{Chandra} Multiwavelength
  Project (ChaMP), we have assembled a sample of ∼ 900 AGN, covering
  3.8 square degrees to a uniform flux limit of 2.7× 10<SUP>-15</SUP>
  ergs cm<SUP>-2</SUP> sec<SUP>-1</SUP>. Using direct spectral fitting
  with \textit{CIAO/Sherpa} we estimate the intrinsic absorbing column
  N<SUB>H</SUB> in each source. Because of the large sample size,
  we are able to determine the N<SUB>H</SUB> distribution within each
  of six flux bins, confirming the trend of increasing obscuration at
  lower fluxes and providing the strongest constraints to date on the
  obscured fraction. We discuss the implications for modeling of the
  CXRB and AGN luminosity function.

Title: Distribution of Faraday Rotation Measure in Jets from Active
    Galactic Nuclei. II. Prediction from Our Sweeping Magnetic Twist
    Model for the Wiggled Parts of Active Galactic Nucleus Jets and Tails
Authors: Kigure, Hiromitsu; Uchida, Yutaka; Nakamura, Masanori;
   Hirose, Shigenobu; Cameron, Robert
Bibcode: 2004ApJ...608..119K
Altcode: 2004astro.ph..2545K
  Distributions of Faraday rotation measure (FRM) and the projected
  magnetic field derived by a three-dimensional simulation of MHD
  jets are investigated based on our ``sweeping magnetic twist
  model.'' FRM and Stokes parameters were calculated to be compared
  with radio observations of large-scale wiggled AGN jets on kiloparsec
  scales. We propose that the FRM distribution can be used to discuss
  the three-dimensional structure of the magnetic field around jets
  and the validity of existing theoretical models, together with the
  projected magnetic field derived from Stokes parameters. In a previous
  paper we investigated the basic straight part of AGN jets by using
  the result of a two-dimensional axisymmetric simulation. The derived
  FRM distribution has a general tendency to have a gradient across
  the jet axis, which is due to the toroidal component of the magnetic
  field generated by the rotation of the accretion disk. In this paper
  we consider the wiggled structure of the AGN jets by using the result
  of a three-dimensional simulation. Our numerical results show that
  the distributions of FRM and the projected magnetic field have a clear
  correlation with the large-scale structure of the jet itself, namely,
  three-dimensional helix. Distributions, seeing the jet from a certain
  direction, show a good matching with those in a part of the 3C 449
  jet. This suggests that the jet has a helical structure and that the
  magnetic field (especially the toroidal component) plays an important
  role in the dynamics of the wiggle formation because it is due to a
  current-driven helical kink instability in our model.

Title: X-ray Emitting AGN Unveiled by the Chandra Multiwavelength
    Project
Authors: Silverman, J.; Green, P.; Aldcroft, T.; Kim, D.; Barkhouse,
   W.; Cameron, R.; Wilkes, B.
Bibcode: 2004ASPC..311..321S
Altcode: 2004apsd.conf..321S; 2003astro.ph.10907S
  We present an X-ray and optical analysis of a flux limited
  (f<SUB>2.0-8.0 keV</SUB> &gt; 10<SUP>-14</SUP> erg s<SUP>-1</SUP>
  cm<SUP>-2</SUP>) sample of 126 AGN detected in 16 Chandra fields. This
  work represents a small though significant subset of the Chandra
  Multiwavelength Project (ChaMP). We have chosen this limiting flux
  to have a reasonable degree of completeness (50%) in our optical
  spectroscopic identifications. The optical counterparts of these AGN
  are characterized as either broad emission line AGN (BLAGN; 59%),
  narrow emission line galaxies (NELG; 20%) or absorption line galaxies
  (ALG; 12%) without any evidence of an AGN signature. Based on their
  X-ray luminosity and spectral properties, we show that NELG and ALG are
  primarily the hosts of obscured AGN with an intrinsic absorbing column
  in the range of 10<SUP>21.5</SUP>&lt; N<SUB>H</SUB>&lt;10<SUP>23.3</SUP>
  cm<SUP>-2</SUP>. While most of the BLAGN are unobscured, there are a
  few with substantial absorption. X-ray surveys such as the ChaMP nicely
  complement optical surveys such as the SDSS to completely determine
  the demographics of the AGN population.

Title: Distribution of Faraday Rotation Measure in Jets from Active
    Galactic Nuclei. I. Predictions from our Sweeping Magnetic Twist Model
Authors: Uchida, Yutaka; Kigure, Hiromitsu; Hirose, Shigenobu;
   Nakamura, Masanori; Cameron, Robert
Bibcode: 2004ApJ...600...88U
Altcode: 2003astro.ph..9605U
  Using the numerical data of MHD simulation for active galactic nucleus
  (AGN) jets based on our ``sweeping magnetic twist model,'' we calculated
  the Faraday rotation measure (FRM) and the Stokes parameters to compare
  with observations. We propose that the FRM distribution can be used to
  discuss the three-dimensional structure of magnetic field around jets,
  together with the projected magnetic field derived from the Stokes
  parameters. In the present paper, we assumed the basic straight part
  of the AGN jet and used the data of axisymmetric simulation. The FRM
  distribution that we derived has a general tendency to have gradient
  across the jet axis, which is due to the toroidal component of the
  helical magnetic field generated by the rotation of the accretion
  disk. This kind of gradient in the FRM distribution is actually observed
  in some AGN jets, which suggests a helical magnetic field around the
  jets and thus supports our MHD model. Following this success, we are now
  extending our numerical observation to the wiggled part of the jets,
  using the data of three-dimensional simulation based on our model,
  in an upcoming paper.

Title: Stormy Weather
Authors: Cameron, Robert
Bibcode: 2004ChNew..11...22C
Altcode:
  No abstract at ADS

Title: An Investigation of Loop-Type CMEs with a 3D MHD Simulation
Authors: Kuwabara, J.; Uchida, Y.; Cameron, R.
Bibcode: 2003ASPC..289..389K
Altcode: 2003aprm.conf..389K
  CMEs have erupted filaments (core) and flux loops that lie over the
  filament (leading edge) and a cavity between the core and leading
  edge. In one model ``Flux loops are pushed up by erupted filaments and
  expand upwards" which roughly explains much about CMEs. But there are
  some CMEs with characteristics that are inexplicable with this model,
  which have a twisted structure along the loop and the structure
  of a convex lens at the loop top (Illing and Hundhausen 2000). We
  consider Torsional Alfven Wave (TAW) propagation as the cause of these
  characteristics for some CMEs, and have studied this with a 3D MHD
  simulation. As a result, we found that TAW propagation most likely
  explains these characteristics for some CMEs and that a TAW can carry
  out plasma from the chromosphere to coronal space along the loop. We
  propose a new scenario about the occurrence of CMEs based on results
  of our simulation and observations.

Title: Optical spectroscopic followup of serendipitous Chandra
sources: the Chandra Multiwavelength Project (ChaMP)
Authors: Silverman, J.; Green, P.; Wilkes, B.; Foltz, C.; Smith,
   P.; Smith, C.; Kim, Dong-Woo; Morris, D.; Mossman, A.; Cameron, R.;
   Adelberger, K.; ChaMP Collaboration
Bibcode: 2003AN....324...97S
Altcode:
  A primary goal of the Chandra Multiwavelength Project (ChaMP) is
  to investigate the evolution of Active Galactic Nuclei (AGN) and
  quasars by measuring the luminosity function out to z&gt;=4 including
  obscured AGN that have been missed by previous surveys. To do so,
  we are acquiring spectra of optical counterparts to serendipitious
  X-ray sources detected by Chandra for classification and redshift
  determination. We have amassed about 200 spectra using the FLWO 1.5m,
  WIYN 3.5m, CTIO/4m, Magellan and the MMT 6.5m. We have classified
  the majority of optical counterparts as 65 AGN, 14 galaxies. The
  remaining counterparts are either stars (8 clusters (1 fields. With
  a limiting magnitude of r<SUP>'</SUP>=22 for spectroscopic followup,
  we are able to detect quasars out to z ~ 5 and galaxies out to z ~
  0.7. This preliminary sample forms the foundation for our measurement
  of the X-ray luminosity function of AGNs out to z ~ 4.

Title: Quantitative measure of quiet photospheric magnetic fields
Authors: Zirin, H.; Cameron, R.
Bibcode: 2002AAS...200.3903Z
Altcode: 2002BAAS...34..701Z
  We have analyzed a set of 110 Stokes V spectra of the quiet Sun taken
  with the spectrovideomagnetograph at BBSO June 23, 2000. The 480x512
  pixel spectrograms are bundled into 3 pixel (1 arc sec) spectra, giving
  160 distinct spectra on each frame, or 16400 spectra overall. An element
  of magnetic network was included in each spectrogram, so that actual
  splitting measurements could be used to check absolute calibration
  of the field measures. In each case we measured the V signal in both
  5250 and 5247 and compared the values. If the ratio was 3:2 as given by
  the g-factors, the data must represent true measured magnetic fields,
  since random noise does not understand g-factors. We find the mean
  field on each spectrum to range from 3 to 49 gauss in the different
  frames, and the median absolute field, from 13 to 30 G. In all cases the
  difference between V(5250) and 1.5xV( 5247) is zero within 1.2 standard
  errors. To check the popular ``emperor's new clothes" model in which
  the fields measured are due to invisible spots with kilogauss fields,
  we calculate the mean value of 1.5xV(5247)/0.78- V(5250), expected to
  be zero for that model. Rather than zero, that result is typically 3
  standard errors from zero, and invariably negative. That result means
  that the V(5250) is not saturated, as would be expected in the kilogauss
  model. Thus the emperor, in fact, has no clothes. The fields measured in
  network elements run from 250 to 700 gauss, and are typically confirmed
  within 20% by the measured splitting. The existence of fields of mixed
  polarity and strength &gt;10 gauss everywhere in the photosphere gives
  an explanation for the support of the chromosphere, which has a scale
  height of 1000 Km instead of the expected hydrostatic scale height
  &lt;200 Km, as well as the filtering out of unionized high-FIP elements,
  which cannot be supported by the magnetic fields, from the solar wind.

Title: The true structure of weak solar magnetic fields
Authors: Zirin, H.; Cameron, R.
Bibcode: 2002ocnd.confE..30Z
Altcode:
  No abstract at ADS

Title: Loop-Type CME Produced by Magnetic Reconnection of Two Large
    Loops at the Associated Arcade Flare
Authors: Uchida, Y.; Kuwabara, J.; Cameron, R.; Suzuki, I.; Tanaka,
   T.; Kouduma, K.
Bibcode: 2002mwoc.conf..199U
Altcode:
  We claim from observational analyses that there are, at least, two
  distinctly different types among CME's: One with a bubble shape
  expanding roughly isotropically with constant velocity caused by
  explosive flares (Bubble-type), and the other with a large loop shape
  whose anchor point in the middle is released by the occurrence of an
  arcade flare between the footpoints of CME's, rising with acceleration
  and deformation (Loop-type). The characteristic difference between these
  types is that the footpoints stay fixed on the solar surface in the
  Loop-type, whereas the structure does not have such fixed footpoints
  for the Bubble-type since the skirts of the bubble (Moreton wave
  and EIT wave separately propagating) sweep on the solar surface. We
  investigate MHD models for these two types of CME's, fulfilling the
  observed characteristics described above, with our 3D MHD simulations,
  and show dynamic behaviors of those with movies. We believe that these
  are examples of new generation approach with time-dependent 3D MHD
  modelling, allowing actual comparison of dynamic models with dynamic
  results from advanced observations.

Title: The Chandra Multi-wavelength Project (ChaMP): Preliminary
    results of X-ray Analysis
Authors: Kim, D. -W.; Cameron, R.; Drake, J.; Freeman, P.; Fruscione,
   A.; Gaetz, T. J.; Green, P. J.; Grimes, J.; Ghosh, H.; Kashyap, V.;
   Schlegel, E.; Vikhlinin, A.; Wilkes, B.; Tananbaum, H.
Bibcode: 2001tysc.confE.222K
Altcode:
  We present preliminary results of X-ray data analysis as part of the
  Chandra Multi-wavelength Project. We describe basic data corrections,
  screening and source analysis procedures. About 1/4 of 160 fields
  selected in AO1 and AO2 have been processed through the ChaMP
  X-pipeline. About 2000 sources are detected (this number may not be
  prorated). Average X-ray source properties in terms of LogN-LogS,
  X-ray color, optical color and X-ray to optical luminosity ratio
  are discussed.

Title: Optical Classification of Chandra Serendipitous Sources by
    the ChaMP
Authors: Green, Paul J.; Cameron, Robert
Bibcode: 2001tysc.confE..53G
Altcode:
  We describe our ongoing optical imaging and spectroscopy of a deep,
  wide-area sample of serendipitous X-ray sources detected in Chandra
  archival images. The Chandra Multiwavelength Project (ChaMP) thus
  enables studies of the nature, evolution, and clustering of X-ray
  selected AGN and galaxies. Chandra's subarcsecond astrometry enables
  unambiguous identification of optical counterparts, and the broadband
  X-ray sensitivity (0.3-8keV) means that our sample is less affected
  by absorption than previous optical, UV, or soft X-ray surveys. Unlike
  radio surveys , the ChaMP will allow the first complete census of the
  intrinsic population of AGN (not just the radio bright fraction). We
  present initial results that will eventually encompass a sample of
  thousands of serendipitous sources detected in 150 Chandra archival
  images, to constrain the X-ray luminosity function and its evolution.

Title: The Field Strength of the Quiet Sun Magnetic Elements
Authors: Zirin, H.; Cameron, R.
Bibcode: 2001AAS...198.7105Z
Altcode: 2001BAAS...33..893Z
  By attaching the videomagnetograph to the Coude spectrograph at BBSO,
  we can measure weak fields down to 10-20 gauss, and splittings down
  to 200 gauss. Using Stenflo's technique of comparing 5250 and 5247,
  we find no saturation; the lines (corrected for g-factor) give equal
  results within a few per cent and are truly weak. The V measurements
  are calibrated by comparison to Zeeman splitting measures above 200
  gauss. The filling factor is unity and there are no hidden strong
  fields. We find noevidence for kilogauss fileds in the quiet Sun. While
  noise limits the agreement of the two lines below 20 gauss, there is
  a detectable V signal almost everywhere on the Sun, both unipolar
  and mixed, of the order of 5 gauss. We call the new instrument the
  spectrovideo-magnetograph (SPVMG). This work supported by the NSF.

Title: Blast Waves in the Magnetized Solar Atmosphere
Authors: Cameron, R.; Uchida, Y.
Bibcode: 2001AGUSM..SH42A09C
Altcode:
  Solar flares convert large amounts of magnetic energy into thermal
  and bulk plasma motions. Such large changes in the magnetic field and
  plasma properties excite the available wave modes. Not all modes are
  equally excited of course and, in principle, this can be used to probe
  the flare mechanism. In practice however we are still at the stage of
  identifying the different modes we see. The initial breakthrough in this
  regard occurred in the early 1970s when Uchida (Uchida 1968) identified
  the previously observed Moreton waves (Moreton and Ramsey 1960) as the
  skirt of a fast mode shock propagating in the Corona. This picture
  has remained essentially unchanged since. In the 1990s the regular
  observation of the sun in EUV wavelengths revealed the existence of a
  new blast related wave: the EIT wave. The most distinctive difference
  between the behavior of the two types of waves is their different
  velocities, with the Moreton wave being about twice as fast as the EIT
  wave. Where the two waves are similar however is in the fact that they
  can both propagate almost isotropically. For the Moreton wave this is
  expected as the Moreton wave is a fast mode disturbance. For the EIT
  wave the isotropic behavior suggests that the information is also being
  carried by the fast mode. We suggest that the difference between the
  two types of modes is not in the way the information is being carried,
  but rather in the information content of the two different types of
  waves. The Moreton wave conveys the information of the sharp, rapid
  energy release associated with the impulsive phase of the flare. The EIT
  wave conveys information as to the ejection of excess mass and energy
  from the system via the slow mode. Unlike the simple spiked structure
  which characterizes the impulsive phase, the time-scale associated with
  the energy release is determined by the bulk mass motion along the
  magnetic field lines - typically the slow mode velocity.. It will be
  shown that this variation in the `source term' of the EIT disturbance
  gives rise to an apparent velocity consistent with the EIT observations.

Title: Spectovideomagnetograph results and the Stokes V assymmetry
Authors: Cameron, R.; Zirin, H.
Bibcode: 2001AAS...198.7104C
Altcode: 2001BAAS...33R.893C
  The Spectrovideomagnetograph at Big Bear Solar Observatory was used
  to obtain several thousand individual spectra of small elements
  on the solar surface. These measurements display the well known
  Stokes V assymmetry, however because the BBSO SPVMG has a significant
  different spatial and temporal resolution than previous measurements,
  the assymmetry has different properties. In this poster we present our
  measurements of the assymmetry and use them to place constraints on the
  mechanism producing the assymmetry. We then discuss how the assymmetry
  contaminates other quantities derived from the SPVMG measurements, and
  how this contamination can be minimized and controlled in our data set.

Title: Rotational Signature of Disk Spicules in H-alpha
Authors: Lee, C.; Cameron, R.; Wang, H.
Bibcode: 2001AGUSM..SP41B09L
Altcode:
  The Littrow spectrograph at Big Bear Solar Observatory (BBSO) can
  produce a 4-dimensional data array, the intensity as a function of
  position, wavelength and time. A week long observation at BBSO was
  carried out on August 25-30, 1997. The spectral scan data is unique in
  the sense that Doppler maps can be constructed free from mis-alignment
  problems. We selected the best data set obtained on August 26 for the
  present study. A number of disk spicules were identified and analysed
  by considering their Doppler map and time evolution at different
  wavelengths. It is estimated that 1/3 of the chosen disk spicules
  are found to display rotational signature. The result is the first
  clearest demonstration of spicule rotation. The cloud model of Beckers'
  was used to determine a lower bound for the angular velocity.

Title: The Spectrovideomagnetograph Reveals the True Strength of
    Photospheric Magnetic Fields
Authors: Zirin, H.; Cameron, R.
Bibcode: 2001AGUSM..SH32C04Z
Altcode:
  We present new observations of weak solar magnetic fields from an
  instrument which we term the spectrovideomagnetograph (SPVMG). The
  sensing system of the videomagnetograph is attached to the Coude
  spectrograph at Big Bear and yields a high sensitivity. Using the
  criteria introduced by Stenflo, we measure the Stokes V and I components
  for the lines FeI 5250 and 5247 in hundreds of spectra. We find that
  from 20 to 350 gauss derived field strengths are strictly proportional
  to the g-factor and show no saturation. Hence the widely accepted strong
  invisible magnetic elements postulated by Stenflo do not exist. The
  filling factor is near unity. We measure the Zeeman splitting directly
  down to 200 gauss and find good correspondence with our V measure. We
  find that the area (outside of sunspots) of the solar surface occupied
  by magnetic field of different strengths follows a power law in the
  inverse square of the field strength. This applies to fields down to
  200G. This has obvious relevance for turbulent surface dynamo models. We
  find that at least 90% of the solar surface is covered by weak fields
  above 5 gauss, sometimes unipolar and sometimes mixed.

Title: Investigation of Coronal Mass Ejections I. Loop-type with
    Arcade Flare between the Fixed Legs, and Bubble-type Due to Flare
    Blast Waves
Authors: Uchida, Y.; Tanaka, T.; Hata, M.; Cameron, R.
Bibcode: 2001PASA...18..345U
Altcode:
  In this paper, we give arguments that there are two types of
  coronal mass ejection (CME). The first type of CME discussed here
  is the `loop-type', whose occurrence is related to an arcade flare
  somewhere between the footpoints. It was found that there were pre-event
  magnetic connections between the flare location and the locations of the
  footpoints of a CME of this type, and that these connections disappeared
  after the event. This suggests that the footpoints of loop-type CMEs
  are special prescribed points, and this was verified by the observation
  that the footpoints do not move in this type of CME. The other type
  of CME is the `bubble-type', which is associated with the flare blast
  from explosive flares. We confirmed the association of this type of
  CME with the so-called EIT (Extreme Ultra-violet Imaging Telescope)
  waves, but the velocity of expansion of the bubble is twice or more
  greater than that of the EIT waves depending on events. Although EIT
  waves were widely considered to be Moreton waves viewed by SoHO/EIT in
  the solar activity minimum period, recent simultaneous observations
  of both have revealed that the EIT wave is something different from
  the Moreton wave, and propagates separately with a velocity less
  than half that of a Moreton wave. We therefore propose a new overall
  picture: the bubble-type CMEs are the flare-produced MHD blast waves
  themselves, whose skirt is identified as a Moreton wave. EIT waves may
  be interpreted as follows: the slow-mode gas motions from the source
  cause secondary long wavelength fast-mode waves which are trapped
  in the 'waveguide' in the low corona. The secondary long-wavelength
  wave in the fast-mode, which is trapped in the low corona, has a
  slower propagation velocity due to the nature of the waves trapped
  in a 'waveguide'. This trapped wave induces slow-mode motions of
  the gas through a mode-coupling process in the high chromosphere,
  where the propagation velocities of the fast-and slow-mode waves
  match. Three-dimensional MHD simulations for these two types of CME
  are in progress, and are previewed in this paper.

Title: The Chandra Multi-wavelength Project (ChaMP): a Serendipitous
    Survey with Chandra Archival Data.
Authors: Wilkes, B. J.; Green, P.; Brissenden, R.; Cameron, R.;
   Dobrzycki, A.; Drake, J.; Evans, N.; Fruscione, A.; Gaetz, T.; Garcia,
   M.; Ghosh, H.; Grimes, J.; Grindlay, J.; Hooper, E.; Karovska, M.;
   Kashyap, V.; Kim, D. -W.; Kowal, K.; Marshall, H.; Mossman, A.; Morris,
   D.; Nichols, J.; Szentgyorgyi, A.; Tananbaum, H.; van Speybroeck,
   L.; Vikhlinin, A.; Virani, S.; Zhao, P.
Bibcode: 2001ASPC..232...47W
Altcode: 2000astro.ph.11377W; 2001newf.conf...47W
  The launch of the Chandra X-ray Observatory in July 1999 opened a new
  era in X-ray astronomy. Its unprecedented, &lt;0.5" spatial resolution
  and low background are providing views of the X-ray sky 10-100 times
  fainter than previously possible. We have initiated a serendipitous
  survey (ChaMP) using Chandra archival data to flux limits covering
  the range between those reached by current satellites and those of the
  small area Chandra deep surveys. We estimate the survey will cover ~5
  sq.deg./year to X-ray fluxes (2-10 keV) in the range 1E(-13)-6E(-16)
  erg/cm^2/s discovering ~2000 new X-ray sources, ~80% of which are
  expected to be AGN. The ChaMP has two parts, the extragalactic survey
  (ChaMP) and the galactic plane survey (ChaMPlane). ChaMP promises
  profoundly new science return on a number of key questions at the
  current frontier of many areas of astronomy including (1) locating
  and studying high redshift clusters and so constraining cosmological
  parameters (2) defining the true population of AGN, including those
  that are absorbed, and so constraining the accretion history of the
  universe, (3) filling in the gap in the luminosity/redshift plane
  between Chandra deep and previous surveys in studying the CXRB, (4)
  studying coronal emission from late-type stars and (5) search for
  CVs and quiescent Low-Mass X-ray Binaries (qLXMBs) to measure their
  luminosity functions. In this paper we summarize the status, predictions
  and initial results from the X-ray analysis and optical imaging.

Title: The Spectrovideomagnetograph Reveals the True Strength of
    Quiet Sun Magnetic Fields
Authors: Zirin, H.; Cameron, R.
Bibcode: 2000AAS...197.5107Z
Altcode: 2000BAAS...32.1489Z
  We present new observations of weak solar magnetic fields with a
  technique, which we term the spectro-videomagnetograph (SPVMG) which
  permits direct measurement of splittings as small as 200 gauss. Using
  the technique of Stenflo we compared the Stokes V-component for the
  5250 and 5247 lines. Contrary to Stenflo's results, we find no evidence
  for strong fields with small filling factor; i. e., the field strengths
  measured as 200 gaussare really 200 gauss and not some stronger field
  partly filling the sample. For the weakest measured fields this cannot
  be absolutely established, but the evidence supports the existence
  of field elements at least as weak as 200 gauss. Observations of
  active regions also yield new results. In many cases of fields near
  inversion lines, we find doubled sets of Zeeman components, as well as
  `flags,' broad components, usually confined to one side of the line,
  extending to displacements corresponding to thousands of gauss, with
  no corresponding component on the opposite side of the line. We show
  examples of these spectra, along with slit jaw images, but have only
  a limited understanding of the field structures they represent. We
  also have examples of the V-splitting increasing as we approach the
  inversion line. We are struggling to understand these and will at
  least show them, with or without explanation. Finally, the regions
  involving these anomalous Zeeman patterns seem to flare more frequently,
  although statistics are limited. This work has been supported by the
  NSF under ATM-9726147.

Title: The Chandra Multi-wavelength Project (ChaMP): X-ray Data
    Analysis
Authors: Kim, D. -W.; Cameron, R.; Drake, J.; Fruscione, A.; Gaetz,
   T. J.; Garcia, M.; Green, P. J.; Grimes, J.; Kashyap, V.; Prestwich,
   A.; Schlegel, E.; Vikhlinin, A.; Virani, S. N.; Wilkes, B.; Tananbaum,
   H.; Freedman, D.; ChaMP Collaboration
Bibcode: 2000HEAD....5.2604K
Altcode: 2000BAAS...32.1223K
  We present step-by-step X-ray data analysis procedures as part of
  the Chandra Multi-wavelength Project. They consist of additional data
  corrections and data screening post CXC Standard Data Processing Rev
  1 and the determination of sources and their X-ray properties. Using 3
  deep ACIS imaging fields (MS 1137.5+6625, CL0848.6+4453 and A0620-00)
  with exposure times ranging from 50 ks to 190 ks, we discuss in
  particular gain correction, aspect correction, removing bad pixels and
  node boundaries, removing ACIS flaring pixels, streak correction for
  the S4 chip and excluding high background intervals. Optimal parameters
  for source detection and X-ray source properties such as X-ray colors
  are also discussed.

Title: The ChaMP: Keck Spectroscopy of Serendipitous Chandra Sources
Authors: Green, P. J.; Chaffee, F. H.; Cameron, R.; Virani, S. N.;
   Dey, A.; Jannuzi, B.; Kindt, A.; van Speybroeck, L.; Tananbaum, H.;
   Wilkes, B.; ChaMP Collaboration
Bibcode: 2000HEAD....5.2618G
Altcode: 2000BAAS...32.1226G
  We describe the X-ray and optical characteristics of faint serendipitous
  X-ray sources detected during a deep (120ksec) Chandra exposure with
  ACIS. While the target is MS 1137.5+6625, the second most distant
  cluster of galaxies in the Einstein Extended Medium Sensitivity Survey
  (EMSS) at redshift 0.78, as part of the Chandra Multiwavelength Project
  (ChaMP), we obtained Keck spectroscopy of a dozen optical counterparts
  in an adjacent field (7 arcmin off-axis) that reveals an intriguing
  variety of objects, dominated by AGN and galaxies between redshifts
  of 0.5 to 2.

Title: The Chandra Multi-wavelength Project (ChaMP): a serendipitous
    X-ray Survey using Chandra Archival Data
Authors: Wilkes, B.; Green, P.; Cameron, R.; Evans, N.; Ghosh, H.;
   Kim, D. W.; Tananbaum, H.; ChaMP Collaboration
Bibcode: 2000HEAD....5.2105W
Altcode: 2000BAAS...32.1212W
  The Chandra X-ray Observatory, launched in July 1999, has begun a new
  era in X-ray astronomy. Its unprecedented, ~ 0.5" spatial resolution and
  low background provide views of the X-ray sky 10-100 times fainter than
  previously possible. We have begun a serendipitous X-ray survey using
  Chandra archival data to flux limits in between those reached by earlier
  satellites and those of the small area, Chandra deep surveys. The survey
  will cover ~ 5 sq.deg. per year to X-ray fluxes (2-10 keV) in the range
  10<SUP>-13}-6<SUP>{-16</SUP></SUP> erg cm<SUP>2</SUP> s<SUP>-1</SUP>
  and include ~3000 sources per year, ~ 70% of which are expected to be
  active galactic nuclei (AGN). Optical imaging of the ChaMP fields is
  underway at NOAO and SAO telescopes using SDSS g',r',z' colors with
  which we will be able to classify the X-ray sources into object types
  and, in some cases, estimate their redshifts. We are also planning to
  obtain optical spectroscopy of a well-defined subset of fields to allow
  confirmation of classification and redshift determination. All X-ray
  and optical results and supporting optical data will be placed in the
  ChaMP archive within a year of the completion of our data analysis. Over
  the five years of Chandra operations, ChaMP will provide both a major
  resource for Chandra observers and a key research tool for the study
  of the cosmic X-ray background and the individual source populations
  which comprise it. ChaMP promises profoundly new science return on
  a number of key questions at the current frontier of many areas of
  astronomy including the Cosmic X-ray Background, locating and studying
  high redshift clusters and so constraining cosmological parameters,
  defining the true population of quasars and studying coronal emission
  from late-type stars that are almost fully convective. An overview of
  the ChaMP will be presented including an introduction to our methods
  and early results many of which will be presented in more detail in
  accompanying papers at this meeting.

Title: Tangential Field Changes in the Great Flare of 1990 May 24
Authors: Cameron, Robert; Sammis, Ian
Bibcode: 1999ApJ...525L..61C
Altcode:
  We examine the great (solar) flare of 1990 May 24 that occurred
  in active region NOAA 6063. The Big Bear Solar Observatory
  videomagnetograph Stokes V and I images show a change in the
  longitudinal field before and after the flare. Since the flare occurred
  near the limb, the change reflects a rearrangement of the tangential
  components of the magnetic field. These observations lack the 180°
  ambiguity that characterizes vector magnetograms.

Title: Chromospheric Sources of Coronal Rays
Authors: Zirin, H.; Cameron, R.
Bibcode: 1999AAS...194.7808Z
Altcode: 1999BAAS...31..962Z
  TRACE images in the 171A FeIX line show coronal rays or small streamers
  from network elements. We obtained chromospheric images in center and
  wing of Hα at BBSO to investigate the relation of these to spicule
  activity at the base, as well as to brightenings and other changes in
  the underlying chromosphere. There is a close match of the brightest
  Hα centerline elements to coronal rays; other network elements
  are seen. Spicule activity does not appear to play a big role. The
  coronal changes are fairly slow. We shall also present new data on
  spicule lifetimes.

Title: Axisymmetric Magnetoconvection in a Twisted Field: the effect
    of Compressibility
Authors: Cameron, R.
Bibcode: 1999AAS...194.5615C
Altcode: 1999BAAS...31..914C
  The magnetic flux threading the solar surface is believed to be
  concentrated by convective motions into kilogauss strength flux
  tubes. What is less well known is the extent to which convective motions
  also concentrates the vertical current threading the solar surface. This
  question can be addressed using the non-ideal MHD approximation. As
  is the case with most such nonlinear problems a numerical treatment
  is called for. This issue is perhaps best treated in an axisymmetric
  geometry, where the computational cost of the calculations remains
  modest (2 (1)/(2) dimensional) compared with a full 3 dimensional
  simulation, and where flux tubes rather than flux sheets (which form in
  2 (1)/(2) dimensional planar simulations) are produced. The problem
  then equates to that of twisted, axisymmetric magnetoconvection,
  which has been treated in the Boussinesq problem by Jones and Galloway
  (1993). The results obtained in the Boussinesq problem indicate that
  the problem is sensitive to the way in which the azimuthal components
  are generated by the boundary conditions. This paper extends that work
  by including the effect of compressibility. Compressible axisymmetric
  magnetoconvection has two non-dimensional parameters in addition
  to those describing the Boussinesq problem. To isolate the effect
  of compressibility, we treat the same cases as Jones and Galloway,
  and vary the two additional parameters.

Title: Variability of Solar UV Irradiance Related to Bright Magnetic
Features Observed in Call K-Line: Relationship between Lyman alpha
    and K-line Report for UARS funding agency
Authors: Zirin, Harold; Cameron, Robert
Bibcode: 1999STIN...9910690Z
Altcode:
  In this report we comment on the relationship between the Lyman alpha
  and Calcium K-line emission from the Sun. We firstly examine resolved
  Lyman alpha images (from TRACE) and resolved K-line images. We find
  that the Lyman alpha emission is consistent with a linear dependence
  on the K-line emission. As this is in conflict with the analysis
  of Johannesson et al.(1995, 1998) we proceed by comparing the disk
  integrated Lyman alpha flux as a function of ratio between the disk
  integrated Mg II core and wing fluxes (Johannesson et al (1998) having
  previously found a linear dependence between this index and the BBSO
  K-line index). We find that a reasonably good fit can be obtained,
  however note the discrepancies which lead Johannesson et al to consider
  the square root relationship. We suggest an alternative interpretation
  of the discrepancy.

Title: A new estimate of the solar meridional flow
Authors: Cameron, R.; Hopkins, A.
Bibcode: 1998SoPh..183..263C
Altcode:
  We present a new method for measuring the solar magnetic meridional
  flow, and provide a comparison with other recent work. We have
  performed a least-squares fit to azimuthally averaged Mount Wilson
  Observatory synoptic data encompassing Carrington rotations 1722 to
  1929 to produce an estimate of the solar meridional flow. A parametric
  fit to our results expresses the solar meridional flow as v(φ) =
  28.5 sin2.5 φ cos φ.

Title: New Studies of Polar Spicules
Authors: Zirin, H.; Cameron, R.
Bibcode: 1998AAS...192.1506Z
Altcode: 1998BAAS...30..840Z
  We have studied several hundred images of solar spicules obtained
  on June 18 and 19 and July 15 of 1997. The observations were made at
  BBSO with the 65cm telescope feeding a Zeiss 1/4 Angstroms filter and
  a 1536x1024 Kodak CCD. Overexposed observations were made above the
  limb as well as normal exposures on the limb. The filter was tuned
  to Hα -0.65A and a 30sec interval was used. We were limited to a
  single wavelength because new software was being installed in a new
  control computer. The images obtained were processed by high-pass
  digital filtering of the original FITS images and reregistered by an
  FFT technique. The image scale is 0.17 arcsec per pixel. The disk was
  observed on June 18, 1997 to detect the sources of macrospicules and
  the limb was observed by overexposure on June 19 to determine the height
  trajectory of the faintest Hα We found that: Many more spicules go up
  than come down. There are numerous double and multiple spicules. The
  macrospicules come from normal network elements and start with an
  "Eiffel tower" shape. There is evidence of magnetic changes underlying
  these features. Both long macrospicules and complex eruptions are
  important at the pole. There is some evidence for rotation in spicules.

Title: A Combined X-Ray and Gamma Ray Study of the Seyfert Galaxies
    NGC 7469 and NGC 3227
Authors: Cameron, Robert
Bibcode: 1996rxte.prop10293C
Altcode:
  We propose XTE observations of the Seyfert 1 galaxies NGC 7469 and
  NGC 3227, to be combined with gamma ray spectra of these AGN obtained
  with the Compton OSSE instrument. The combined XTE and OSSE data,
  providing continuous energy coverage from 2 keV to &gt;1 MeV, will
  be used to test and refine the increasingly complex Seyfert spectral
  models in this energy range. The known variability of these Seyferts
  may also give information on the separate emission components in the
  broadband X-ray spectra, since we expect correlated variability between
  the intrinsic source X-ray flux and reflected emission. Finally,
  improved models for Seyfert AGN will provide better constraints on
  the contribution of Seyferts to the diffuse X-ray background.

Title: The Hard X-Ray Telescope Mission
Authors: Gorenstein, P.; Joensen, K.; Romaine, S.; Worrall, D.;
   Cameron, R.; Weisskopf, M.; Ramsey, B.; Bilbro, J.; Kroeger, R.;
   Gehrels, N.; Parsons, A.; Smither, R.; Christensen, F.; Citterio,
   O.; von Ballmoos, P.
Bibcode: 1995AAS...187.7203G
Altcode: 1995BAAS...27Q1388G
  The Hard X-Ray Telescope (HXT) mission concept contains focusing
  telescopes that collectively, observe simultaneously from the
  ultraviolet to 100 keV and in several narrow bands extending to 1
  MeV. In pointed observations HXT is expected to have an order of
  magnitude more sensitivity and much finer angular resolution in the
  10 to 100 keV band than all current and currently planned future
  missions, and considerably more sensitivity for detecting narrow
  lines in the 100 keV to 1 MeV regime. The detectors are small, cooled
  arrays of relatively low mass with very good energy resolution and
  some polarization sensitivity. HXT contains two types of hard X-ray
  telescopes. One type, called the modular modular telescope (MMT)
  utilizes a novel type of multilayer coating and small graze angles to
  extend the regime of focusing to 100keV. There is a two stage imaging
  detector at each focus, a CCD for X-rays &lt; 10 keV followed down
  stream by either a germanium strip array or cadmium zinc telluride array
  for 10-100 keV X-rays. The other type of telescope, called the Laue
  Crystal Telescope (LCT) is a single adjustable array of several hundred
  Ge crystals that focus by Laue scattering. Individual picomotors adjust
  the angle of each crystal to diffract photons of a fixed energy to
  the same point along the optic axis where they converge upon a movable
  array of cooled germanium detectors. The LCT will have high sensitivity
  for detecting narrow X-ray lines of known energy such as those expected
  from Type 1 supernova. The UV monitor is a three telescope system that
  provides coverage in the ultraviolet band for study of time correlated
  changes across the broad electromagnetic spectrum of an AGN such as
  are expected in ``reverberation'' models. A WWW page will be created as
  a public bulletin board. This work is supported by NASA grant NAG8-1194

Title: New Observations of the Optical Spectrum of SiO + and the
    Prediction of Its Rotational Spectrum
Authors: Zhang, L.; Cameron, R.; Holt, R. A.; Scholl, T. J.; Rosner,
   S. D.
Bibcode: 1993ApJ...418..307Z
Altcode:
  The (0, 0) and (1, 0) bands of the
  B<SUP>2</SUP>Σ<SUP>+</SUP>-Χ<SUP>2</SUP>Σ<SUP>+</SUP> system of
  <SUP>28</SUP>Si<SUP>16</SUP>O<SUP>+</SUP> have been observed with
  very high resolution using the technique of laser-induced fluorescence
  from a mass-selected fast ion beam. The data yield values of the υ"
  = 0 rotational and fine-structure constants with an improvement in
  precision by about an order of magnitude over earlier work. This makes
  it possible to predict the frequencies of pure rotational transitions
  within this vibrational level at a level of precision that allows
  unambiguous comparison with molecular lines observed in interstellar
  clouds. In particular, the transition (J = 5/2, N = 2) → (J = 3/2,
  N = 1), which has been considered as the source of the observed U86.2
  line at 86,243.45(40) MHz, is predicted to occur at 86,037(6) MHz.

Title: Search for solar axions
Authors: Lazarus, D. M.; Smith, G. C.; Cameron, R.; Melissinos, A. C.;
   Ruoso, G.; Semertzidis, Y. K.; Nezrick, F. A.
Bibcode: 1992PhRvL..69.2333L
Altcode:
  We have searched for a flux of axions produced in the Sun by exploiting
  their conversion to x rays in a static magnetic field. The signature of
  a solar axion flux would be an increase in the rate of x rays detected
  in a magnetic telescope when the Sun passes within its acceptance. From
  the absence of such a signal we set a 3σ limit on the axion coupling
  to two photons g<SUB>aγγ</SUB>≡1/M&lt;3.6×10<SUP>-9</SUP>
  GeV<SUP>-1</SUP>, provided the axion mass m<SUB>a</SUB>&lt;0.03
  eV and &lt;7.7×10<SUP>-9</SUP> GeV<SUP>-1</SUP> for 0.03
  &lt;m<SUB>a</SUB>&lt;0.11 eV.

Title: GRO J0422+32
Authors: Harmon, B. A.; Wilson, R. B.; Fishman, G. J.; Meegan, C. A.;
   Paciesas, W. S.; Briggs, M. S.; Finger, M. H.; Cameron, R.; Kroeger,
   R.; Grove, E.
Bibcode: 1992IAUC.5584....2H
Altcode: 1992IAUC.5584....1H
  B. A. Harmon, R. B. Wilson, G. J. Fishman, and C. A. Meegan, Marshall
  Space Flight Center, NASA; W. S. Paciesas and M. S. Briggs, University
  of Alabama, Huntsville; M. H. Finger, Computer Sciences Corporation;
  R. Cameron, Universities Space Research Association; and R. Kroeger,
  and E. Grove, Naval Research Laboratory, report for BATSE and OSSE:
  "The hard x-ray/gamma-ray transient discovered by the BATSE experiment
  on the Compton Observatory (IAUC 5580) continued to emit at high
  intensity, about 3 Crab (40-230 keV), over the past three days. The
  Observatory was re-pointed on Aug. 11.07 UT, so that the source is
  observable by all four Compton instruments. An improved location based
  on combined BATSE and OSSE data is R.A. = 4h22m.1, Decl. = +32 49'
  (equinox J2000.0; uncertainty radius of 0.2 deg). A significant flux
  is seen to at least 500 keV, with a hard spectrum. The source continues
  to show strong variability on all timescales."

Title: GRO/OSSE Observations of Nuclear Line Emission from the
    Intense Flares of June 1991
Authors: Murphy, R. J.; Share, G. H.; Johnson, W. N.; Kinzer, R. L.;
   Kroeger, R.; Kurfess, J. D.; Strickman, M. S.; Grove, J. E.; Cameron,
   R.; Jung, G.; Grabelsky, D.; Matz, S. M.; Purcell, W.; Ulmer, M. P.;
   Frye, G.; Jenkins, T.; Jensen, C.
Bibcode: 1992AAS...180.3407M
Altcode: 1992BAAS...24Q.784M
  The Oriented Scintillation Spectroscopy Experiment (OSSE) on the
  Compton Gamma Ray Observatory is comprised of 4 independently-oriented
  large-area ( ~ 500 cm(2) /detector at 511 keV) NaI detectors
  covering the energy range from 0.050 to 10 MeV. Solar observations
  are typically performed with two of the detectors staring at the Sun
  and two alternating between viewing the Sun and viewing background
  regions on two-minute timescales. In June of 1991, OSSE observed 4
  of the X10+ flares from Active Region 6659. Intense gamma-ray line
  emission at 0.511 MeV (positron annihilation) and 2.223 MeV (neutron
  capture), and from several deexcitation lines of carbon and oxygen
  were recorded. Using a combination of data from sunward-pointing
  and off-pointing detectors to avoid saturation effects during the
  intense portions of the flares, background-subtracted spectra have
  been obtained. These spectra were fit to derive photon fluxes for
  the above-mentioned gamma-ray lines. Preliminary lower limits to the
  integrated fluxes in the 2.223 MeV line (not accounting for saturation
  effects and based on data collected only during the OSSE observation
  times) are about 300, 200, 30 and 100 photons/cm(2) for the June 4, 6,
  9 and 11 flares, respectively. This is to be compared to a fluence of
  about 300 photons/cm(2) for the 1982 June 3 flare observed by the SMM
  Gamma-Ray Spectrometer. Integrated fluxes for the other lines will be
  presented and compared to line flux measurements of flares obtained
  with the SMM/GRS. This work is supported under NASA contract S10987C.

Title: GRO/OSSE Observations of the Intense June 1991 Flares from
    AR 6659
Authors: Share, G. H.; Murphy, R. J.; Johnson, W. N.; Kinzer, R. L.;
   Kroeger, R.; Kurfess, J. D.; Strickman, M. S.; Cameron, R.; Jung,
   G.; Grabelsky, D.; Matz, S. M.; Purcell, W.; Ulmer, M. P.; Frye, G.;
   Jenkins, T.; Jensen, C.
Bibcode: 1991BAAS...23.1388S
Altcode:
  No abstract at ADS

Title: A search for the coherent production of axions in the milli
    eV range
Authors: Cameron, R.; Melissinos, A. C.; Semertzidis, Y.; Cantatore,
   G.; Rizzo, C.; Ruoso, P.; Zavattini, E.; Halama, H.; Lazarus, D.
Bibcode: 1991pafi.rept...18C
Altcode:
  Axions provide a natural explanation for the absence of CP violation
  in the strong interaction. As weakly interacting light particles they
  are also candidates for the much sought after dark matter allegedly
  responsible for our lack of understanding of galactic dynamics. Beam
  dump, particle decay and astrophysical measurements carried out over the
  past decade have failed to provide positive evidence for their existence
  over a wide range of masses and coupling strengths. This experiment
  attempts to produce and detect scalar and pseudoscalar particles
  coherently produced through the interaction of laser photons with the
  virtual photons of the magnetic fields of superconducting dipole magnets
  as manifested by small changes in the polarization state of the laser
  light. A limit on the coupling of the axion to 2 photons of g(sub a
  gamma gamma) less than 6.67 x 10(exp -7) GeV(exp -1) was achieved.

Title: An Experiment to Produce Light Pseudoscalars and QED Vacuum
    Polarization
Authors: Semertzidis, Y.; Cameron, R.; Cantatore, G.; Melissions,
   A. C.; Rogers, J. T.; Halama, H. J.; Moskowitz, B. E.; Prodell, A. G.;
   Nezrick, F. A.; Zavattini, E.
Bibcode: 1990coax.conf..137S
Altcode:
  No abstract at ADS

