Author name code: rutten-rob
ADS astronomy entries on 2022-09-14
author:("Rutten, Robert J." OR ="Rutten, Rob" OR ="Rutten, Robert" OR ="Rutten, R.J.") NOT =author:"Rutten, R."
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Title: Cornelis de Jager: In Memoriam
Authors: Rutten, Robert J.; Engvold, Oddbjørn; Nieuwenhuizen,
   Adrianus C. T.
Bibcode: 2022SoPh..297...15R
Altcode: 2022arXiv220111496R
  Cornelis ("Kees") de Jager, the co-founder of the journal Solar Physics,
  passed away on 27 May 2021. He was an exemplary human being, a great
  scientist, and he had a large impact on our field. In this tribute,
  we first briefly summarize his life and career and then describe some
  of his solar activities, from his Ph.D. thesis on the hydrogen lines in
  1952 to the book on cycle-climate relations that he completed last year.

Title: Compendium solar spectrum formation
Authors: Rutten, Robert J.
Bibcode: 2021arXiv210302369R
Altcode:
  The solar spectrum conveys most of our diagnostics to find out how
  our star works. They must be understood for utilization, but solar
  spectrum formation is complex because the interaction of matter and
  radiation within the solar atmosphere suffers non-local control in
  space, wavelength, and time. These complexities are summarized and
  illustrated with classic literature. They combine in chromospheric
  spectrum formation.

Title: Small-scale solar surface magnetism
Authors: Rutten, Robert
Bibcode: 2020smvc.book...29R
Altcode: 2021arXiv210514533R
  This contribution to "Solar Magnetic Variability and Climate" reviews
  small-scale magnetic features on the solar surface, in particular,
  the strong-field but tiny magnetic concentrations that constitute
  network and plage and represent most magnetism outside sunspots and
  filaments. Where these are mostly of the same polarity, as in active
  region plage, their occurrence varies with the activity variations
  measured by the sunspot number, but when they appear bipolar-mixed on
  small scales they can also result from granular-scale dynamo action
  that does not vary with the cycle.

Title: SolO campfires in SDO images
Authors: Rutten, Robert J.
Bibcode: 2020arXiv200900376R
Altcode:
  I present the appearance of "Solar Orbiter campfires" in simultaneous
  images from the Solar Dynamics Observatory where most are visible
  although less sharp. I also show such features elsewhere in the SDO
  database. I show some in detail and discuss their nature.

Title: Solar Hα features with hot onsets. IV. Network fibrils
Authors: Rutten, Robert J.; Rouppe van der Voort, Luc H. M.; De
   Pontieu, Bart
Bibcode: 2019A&A...632A..96R
Altcode: 2019arXiv190809315R
  Even in quiet areas underneath coronal holes the solar chromosphere
  contains ubiquitous heating events. They tend to be small scale and
  short lived, hence difficult to identify. Here we do not address
  their much-debated contribution to outer-atmosphere heating,
  but their aftermaths. We performed a statistical analysis of
  high-resolution observations in the Balmer Hα line to suggest
  that many slender dark Hα fibrils spreading out from network
  represent cooling gas that outlines tracks of preceding rapid
  type II spicule events or smaller similar but as yet unresolved
  heating agents in which the main gas constituent, hydrogen, ionizes
  at least partially. Subsequent recombination then causes dark Hα
  fibrils enhanced by nonequilibrium overopacity. We suggest that the
  extraordinary fibrilar appearance of the Hα chromosphere around network
  results from intermittent, frequent small-scale prior heating. <P
  />Movies associated to Fig. 3 and blinkers are available at <A
  href="https://www.aanda.org/10.1051/0004-6361/201936113/olm">https://www.aanda.org</A>

Title: Non-Equilibrium Spectrum Formation Affecting Solar Irradiance
Authors: Rutten, Robert J.
Bibcode: 2019SoPh..294..165R
Altcode: 2019arXiv190804624R
  This is an overview of non-equilibrium aspects of the formation of
  solar continua and lines affecting the contributions by magnetic
  network and plage to spectrally resolved solar irradiance. After a
  brief summary of these contributions and a compact refresher of solar
  spectrum formation, the emphasis is on graphical exposition. Major
  obstacles for simulation-based irradiance studies are how to cope
  with NLTE scattering in the violet and ultraviolet line haze and how
  to cope with retarded hydrogen opacities in infrared and mm radiation.

Title: Automating Ellerman bomb detection in ultraviolet continua
Authors: Vissers, Gregal J. M.; Rouppe van der Voort, Luc H. M.;
   Rutten, Robert J.
Bibcode: 2019A&A...626A...4V
Altcode: 2019arXiv190107975V
  Ellerman bombs are transient brightenings in the wings of Hα 6563 Å
  that pinpoint photospheric sites of magnetic reconnection in solar
  active regions. Their partial visibility in the 1600 Å and 1700 Å
  continua registered routinely by the Atmospheric Imaging Assembly (AIA)
  onboard the Solar Dynamics Observatory (SDO) offers a unique opportunity
  to inventory such magnetic-field disruptions throughout the AIA database
  if a reliable recipe for their detection can be formulated. This is
  done here. We have improved and applied an Hα Ellerman bomb detection
  code to ten data sets spanning viewing angles from solar disc centre
  to the limb. They combine high-quality Hα imaging spectroscopy from
  the Swedish 1 m Solar Telescope with simultaneous AIA imaging around
  1600 Å and 1700 Å. A trial grid of brightness, lifetime and area
  constraints is imposed on the AIA images to define optimal recovery
  of the 1735 Ellerman bombs detected in Hα. The best results when
  optimising simultaneously for recovery fraction and reliability are
  obtained from 1700 Å images by requiring 5σ brightening above the
  average 1700 Å nearby quiet-Sun intensity, lifetime above one minute,
  area of 1-18 AIA pixels. With this recipe 27% of the AIA detections are
  Hα-detected Ellerman bombs while it recovers 19% of these (of which
  many are smaller than the AIA resolution). Better yet, among the top
  10% AIA 1700 Å detections selected with combined brightness, lifetime
  and area thresholds as many as 80% are Hα Ellerman bombs. Automated
  selection of the best 1700 Å candidates therefore opens the entire
  AIA database for detecting most of the more significant photospheric
  reconnection events. This proxy is applicable as a flux-dynamics
  tell-tale in studying any Earth-side solar active region since early
  2010 up to the present.

Title: Solar Ultraviolet Bursts
Authors: Young, Peter R.; Tian, Hui; Peter, Hardi; Rutten, Robert J.;
   Nelson, Chris J.; Huang, Zhenghua; Schmieder, Brigitte; Vissers, Gregal
   J. M.; Toriumi, Shin; Rouppe van der Voort, Luc H. M.; Madjarska, Maria
   S.; Danilovic, Sanja; Berlicki, Arkadiusz; Chitta, L. P.; Cheung, Mark
   C. M.; Madsen, Chad; Reardon, Kevin P.; Katsukawa, Yukio; Heinzel, Petr
Bibcode: 2018SSRv..214..120Y
Altcode: 2018arXiv180505850Y
  The term "ultraviolet (UV) burst" is introduced to describe small,
  intense, transient brightenings in ultraviolet images of solar active
  regions. We inventorize their properties and provide a definition
  based on image sequences in transition-region lines. Coronal signatures
  are rare, and most bursts are associated with small-scale, canceling
  opposite-polarity fields in the photosphere that occur in emerging flux
  regions, moving magnetic features in sunspot moats, and sunspot light
  bridges. We also compare UV bursts with similar transition-region
  phenomena found previously in solar ultraviolet spectrometry and
  with similar phenomena at optical wavelengths, in particular Ellerman
  bombs. Akin to the latter, UV bursts are probably small-scale magnetic
  reconnection events occurring in the low atmosphere, at photospheric
  and/or chromospheric heights. Their intense emission in lines with
  optically thin formation gives unique diagnostic opportunities
  for studying the physics of magnetic reconnection in the low solar
  atmosphere. This paper is a review report from an International Space
  Science Institute team that met in 2016-2017.

Title: Solar ALMA predictions: tutorial
Authors: Rutten, R. J.
Bibcode: 2017IAUS..327....1R
Altcode: 2016arXiv161105308R
  I have proposed that long Hα fibrils are caused by heating events
  of which the tracks are afterwards outlined by contrails of cooling
  gas with extraordinary Hα opacity and yet larger opacity at the ALMA
  wavelengths. Here I detail the radiative transfer background.

Title: Slender Ca II H Fibrils Mapping Magnetic Fields in the Low
    Solar Chromosphere
Authors: Jafarzadeh, S.; Rutten, R. J.; Solanki, S. K.; Wiegelmann, T.;
   Riethmüller, T. L.; van Noort, M.; Szydlarski, M.; Blanco Rodríguez,
   J.; Barthol, P.; del Toro Iniesta, J. C.; Gandorfer, A.; Gizon, L.;
   Hirzberger, J.; Knölker, M.; Martínez Pillet, V.; Orozco Suárez,
   D.; Schmidt, W.
Bibcode: 2017ApJS..229...11J
Altcode: 2016arXiv161003104J
  A dense forest of slender bright fibrils near a small solar active
  region is seen in high-quality narrowband Ca II H images from the SuFI
  instrument onboard the Sunrise balloon-borne solar observatory. The
  orientation of these slender Ca II H fibrils (SCF) overlaps with the
  magnetic field configuration in the low solar chromosphere derived
  by magnetostatic extrapolation of the photospheric field observed
  with Sunrise/IMaX and SDO/HMI. In addition, many observed SCFs are
  qualitatively aligned with small-scale loops computed from a novel
  inversion approach based on best-fit numerical MHD simulation. Such
  loops are organized in canopy-like arches over quiet areas that differ
  in height depending on the field strength near their roots.

Title: Solar H-alpha features with hot onsets. III. Long fibrils in
    Lyman-alpha and with ALMA
Authors: Rutten, R. J.
Bibcode: 2017A&A...598A..89R
Altcode: 2016arXiv160901122R
  In H-alpha most of the solar surface is covered by dense canopies of
  long opaque fibrils, but predictions for quiet-Sun observations with
  ALMA have ignored this fact. Comparison with Ly-alpha suggests that
  the extraordinary opacity of H-alpha fibrils is caused by hot precursor
  events. Application of a recipe that assumes momentary Saha-Boltzmann
  extinction during their hot onset to millimeter wavelengths suggests
  that ALMA will observe H-alpha-like fibril canopies, not acoustic shocks
  underneath, and will yield data more interesting than if these canopies
  were transparent. <P />An additional file is available at the end of
  the PDF file of this article.This study is offered as compliment to
  M.W.M. de Graauw. Our ways, objects, instruments and spectral domains
  parted after the 1970 eclipse but converge here.

Title: Observations and diagnostics of the solar chromosphere
Authors: Rutten, Rob
Bibcode: 2017psio.confE..42R
Altcode:
  No abstract at ADS

Title: Solar Hα features with hot onsets. II. A contrail fibril
Authors: Rutten, R. J.; Rouppe van der Voort, L. H. M.
Bibcode: 2017A&A...597A.138R
Altcode: 2016arXiv160907616R
  The solar chromosphere observed in Hα consists mostly of narrow
  fibrils. The longest typically originate in network or plage and arch
  far over adjacent internetwork. We use data from multiple telescopes
  to analyze one well-observed example in a quiet area. It resulted from
  the earlier passage of an accelerating disturbance in which the gas was
  heated to high temperature as in the spicule-II phenomenon. After this
  passage a dark Hα fibril appeared as a contrail. We use Saha-Boltzmann
  extinction estimation to gauge the onset and subsequent visibilities in
  various diagnostics and conclude that such Hα fibrils can indeed be
  contrail phenomena, not indicative of the thermodynamic and magnetic
  environment when they are observed but of more dynamic happenings
  before. They do not connect across internetwork cells but represent
  launch tracks of heating events and chart magnetic field during launch,
  not at present.

Title: Reconnection brightenings in the quiet solar photosphere
Authors: Rouppe van der Voort, Luc H. M.; Rutten, Robert J.; Vissers,
   Gregal J. M.
Bibcode: 2016A&A...592A.100R
Altcode: 2016arXiv160603675R
  We describe a new quiet-Sun phenomenon which we call quiet-Sun
  Ellerman-like brightenings (QSEB). QSEBs are similar to Ellerman bombs
  (EB) in some respects but differ significantly in others. EBs are
  transient brightenings of the wings of the Balmer Hα line that mark
  strong-field photospheric reconnection in complex active regions. QSEBs
  are similar but smaller and less intense Balmer-wing brightenings
  that occur in quiet areas away from active regions. In the Hα wing,
  we measure typical lengths of less than 0.5 arcsec, widths of 0.23
  arcsec, and lifetimes of less than a minute. We discovered them
  using high-quality Hα imaging spectrometry from the Swedish 1-m
  Solar Telescope (SST) and show that, in lesser-quality data, they
  cannot be distinguished from more ubiquitous facular brightenings,
  nor in the UV diagnostics currently available from space platforms. We
  add evidence from concurrent SST spectropolarimetry that QSEBs also
  mark photospheric reconnection events, but in quiet regions on the
  solar surface. <P />The movies are available in electronic form at <A
  href="http://www.aanda.org/10.1051/0004-6361/201628889/olm">http://www.aanda.org</A>

Title: Hα features with hot onsets. I. Ellerman bombs
Authors: Rutten, R. J.
Bibcode: 2016A&A...590A.124R
Altcode: 2016arXiv160103280R
  Ellerman bombs are transient brightenings of the wings of the Balmer
  lines that uniquely mark reconnection in the solar photosphere. They are
  also bright in strong Ca II and ultraviolet lines and in ultraviolet
  continua, but they are not visible in the optical continuum and the
  Na I D and Mg I b lines. These discordant visibilities invalidate
  all published Ellerman bomb modeling. I argue that the assumption
  of Saha-Boltzmann lower-level populations is informative to estimate
  bomb-onset opacities for these diverse diagnostics, even and especially
  for Hα, and employ such estimates to gauge the visibilities of
  Ellerman bomb onsets in all of them. They constrain Ellerman bomb
  formation to temperatures 10 000-20 000 K and hydrogen densities around
  10<SUP>15</SUP> cm<SUP>-3</SUP>. Similar arguments likely hold for
  Hα visibility in other transient phenomena with hot and dense onsets.

Title: Ellerman Bombs at High Resolution. III. Simultaneous
    Observations with IRIS and SST
Authors: Vissers, G. J. M.; Rouppe van der Voort, L. H. M.; Rutten,
   R. J.; Carlsson, M.; De Pontieu, B.
Bibcode: 2015ApJ...812...11V
Altcode: 2015arXiv150700435V
  Ellerman bombs (EBs) are transient brightenings of the extended wings
  of the solar Balmer lines in emerging active regions. We describe
  their properties in the ultraviolet lines sampled by the Interface
  Region Imaging Spectrograph (IRIS), using simultaneous imaging
  spectroscopy in Hα with the Swedish 1-m Solar Telescope (SST) and
  ultraviolet images from the Solar Dynamics Observatory for Ellerman
  bomb detection and identification. We select multiple co-observed
  EBs for detailed analysis. The IRIS spectra strengthen the view that
  EBs mark reconnection between bipolar kilogauss fluxtubes with the
  reconnection and the resulting bi-directional jet located within the
  solar photosphere and shielded by overlying chromospheric fibrils in
  the cores of strong lines. The spectra suggest that the reconnecting
  photospheric gas underneath is heated sufficiently to momentarily reach
  stages of ionization normally assigned to the transition region and the
  corona. We also analyze similar outburst phenomena that we classify as
  small flaring arch filaments and ascribe to reconnection at a higher
  location. They have different morphologies and produce hot arches in
  million-Kelvin diagnostics.

Title: Ellerman Bombs at High Resolution. IV. Visibility in Na I
    and Mg I
Authors: Rutten, R. J.; Rouppe van der Voort, L. H. M.; Vissers,
   G. J. M.
Bibcode: 2015ApJ...808..133R
Altcode: 2015arXiv150604426R
  Ellerman bombs are transient brightenings of the wings of the solar
  Balmer lines that mark reconnection in the photosphere. Ellerman noted
  in 1917 that he did not observe such brightenings in the Na i D and
  Mg i b lines. This non-visibility should constrain EB interpretation,
  but has not been addressed in published bomb modeling. We therefore
  test Ellerman’s observation and confirm it using high-quality imaging
  spectrometry with the Swedish 1-m Solar Telescope. However, we find
  a diffuse brightness in these lines that seems to result from prior
  EBs. We tentatively suggest this is a post-bomb hot-cloud phenomenon
  also found in recent EB spectroscopy in the ultraviolet.

Title: Ellerman Bombs at High Resolution. II. Triggering, Visibility,
    and Effect on Upper Atmosphere
Authors: Vissers, Gregal J. M.; Rouppe van der Voort, Luc H. M.;
   Rutten, Robert J.
Bibcode: 2013ApJ...774...32V
Altcode: 2013arXiv1307.1547V
  We use high-resolution imaging spectroscopy with the Swedish 1-m Solar
  Telescope (SST) to study the transient brightenings of the wings
  of the Balmer Hα line in emerging active regions that are called
  Ellerman bombs. Simultaneous sampling of Ca II 8542 Å with the SST
  confirms that most Ellerman bombs also occur in the wings of this
  line, but with markedly different morphology. Simultaneous images
  from the Solar Dynamics Observatory (SDO) show that Ellerman bombs
  are also detectable in the photospheric 1700 Å continuum, again with
  differing morphology. They are also observable in 1600 Å SDO images,
  but with much contamination from C IV emission in transition-region
  features. Simultaneous SST spectropolarimetry in Fe I 6301 Å shows that
  Ellerman bombs occur at sites of strong-field magnetic flux cancellation
  between small bipolar strong-field patches that rapidly move together
  over the solar surface. Simultaneous SDO images in He II 304 Å, Fe IX
  171 Å, and Fe XIV 211 Å show no clear effect of the Ellerman bombs
  on the overlying transition region and corona. These results strengthen
  our earlier suggestion, based on Hα morphology alone, that the Ellerman
  bomb phenomenon is a purely photospheric reconnection phenomenon.

Title: Ellerman bombs: fallacies, fads, usage
Authors: Rutten, Robert J.; Vissers, Gregal J. M.; Rouppe van der
   Voort, Luc H. M.; Sütterlin, Peter; Vitas, Nikola
Bibcode: 2013JPhCS.440a2007R
Altcode: 2013arXiv1304.1364R
  Ellerman bombs are short-lived brightenings of the outer wings of Hα
  that occur in active regions with much flux emergence. We point out
  fads and fallacies in the extensive Ellerman bomb literature, discuss
  their appearance in various spectral diagnostics, and advocate their
  use as indicators of field reconfiguration in active-region topography
  using AIA 1700 Å images.

Title: Twists to Solar Spicules
Authors: Rutten, R. J.
Bibcode: 2013ASPC..470...49R
Altcode: 2012arXiv1205.5114R
  Type-II solar spicules appear as long, thin, highly dynamic strands
  of field-tied matter that feed significant mass and energy to the
  corona and solar wind. A recent result is that they exhibit torsional
  Alfvén waves in addition to accelerating outflows and swaying motions
  due to transverse Alfvénic waves. I summarize this finding and then
  re-interpret older observations in its light: the striking similarity
  of near-limb scenes in the outer blue and red wings of H α, and the
  tilts of absorption lines with respect to emission lines in eclipse
  spectra taken in 1973.

Title: LEMUR: Large European module for solar Ultraviolet
    Research. European contribution to JAXA's Solar-C mission
Authors: Teriaca, Luca; Andretta, Vincenzo; Auchère, Frédéric;
   Brown, Charles M.; Buchlin, Eric; Cauzzi, Gianna; Culhane, J. Len;
   Curdt, Werner; Davila, Joseph M.; Del Zanna, Giulio; Doschek, George
   A.; Fineschi, Silvano; Fludra, Andrzej; Gallagher, Peter T.; Green,
   Lucie; Harra, Louise K.; Imada, Shinsuke; Innes, Davina; Kliem,
   Bernhard; Korendyke, Clarence; Mariska, John T.; Martínez-Pillet,
   Valentin; Parenti, Susanna; Patsourakos, Spiros; Peter, Hardi; Poletto,
   Luca; Rutten, Robert J.; Schühle, Udo; Siemer, Martin; Shimizu,
   Toshifumi; Socas-Navarro, Hector; Solanki, Sami K.; Spadaro, Daniele;
   Trujillo-Bueno, Javier; Tsuneta, Saku; Dominguez, Santiago Vargas;
   Vial, Jean-Claude; Walsh, Robert; Warren, Harry P.; Wiegelmann,
   Thomas; Winter, Berend; Young, Peter
Bibcode: 2012ExA....34..273T
Altcode: 2011ExA...tmp..135T; 2011arXiv1109.4301T
  The solar outer atmosphere is an extremely dynamic environment
  characterized by the continuous interplay between the plasma and the
  magnetic field that generates and permeates it. Such interactions play a
  fundamental role in hugely diverse astrophysical systems, but occur at
  scales that cannot be studied outside the solar system. Understanding
  this complex system requires concerted, simultaneous solar observations
  from the visible to the vacuum ultraviolet (VUV) and soft X-rays, at
  high spatial resolution (between 0.1'' and 0.3''), at high temporal
  resolution (on the order of 10 s, i.e., the time scale of chromospheric
  dynamics), with a wide temperature coverage (0.01 MK to 20 MK,
  from the chromosphere to the flaring corona), and the capability of
  measuring magnetic fields through spectropolarimetry at visible and
  near-infrared wavelengths. Simultaneous spectroscopic measurements
  sampling the entire temperature range are particularly important. These
  requirements are fulfilled by the Japanese Solar-C mission (Plan B),
  composed of a spacecraft in a geosynchronous orbit with a payload
  providing a significant improvement of imaging and spectropolarimetric
  capabilities in the UV, visible, and near-infrared with respect to
  what is available today and foreseen in the near future. The Large
  European Module for solar Ultraviolet Research (LEMUR), described
  in this paper, is a large VUV telescope feeding a scientific payload
  of high-resolution imaging spectrographs and cameras. LEMUR consists
  of two major components: a VUV solar telescope with a 30 cm diameter
  mirror and a focal length of 3.6 m, and a focal-plane package composed
  of VUV spectrometers covering six carefully chosen wavelength ranges
  between 170 Å and 1270 Å. The LEMUR slit covers 280'' on the Sun with
  0.14'' per pixel sampling. In addition, LEMUR is capable of measuring
  mass flows velocities (line shifts) down to 2 km s<SUP> - 1</SUP> or
  better. LEMUR has been proposed to ESA as the European contribution
  to the Solar C mission.

Title: The quiet-Sun photosphere and chromosphere
Authors: Rutten, R. J.
Bibcode: 2012RSPTA.370.3129R
Altcode: 2011arXiv1110.6606R
  The overall structure and the fine structure of the solar photosphere
  outside active regions are largely understood, except possibly important
  roles of a turbulent near-surface dynamo at its bottom, internal
  gravity waves at its top, and small-scale vorticity. Classical 1D static
  radiation-escape modelling has been replaced by 3D time-dependent MHD
  simulations that come closer to reality. The solar chromosphere, in
  contrast, remains ill-understood although its pivotal role in coronal
  mass and energy loading makes it a principal research area. Its fine
  structure defines its overall structure, so that hard-to-observe
  and hard-to-model small-scale dynamical processes are the key to
  understanding. However, both chromospheric observation and chromospheric
  simulation presently mature towards the required sophistication. The
  open-field features seem of greater interest than the easier-to-see
  closed-field features.

Title: Ubiquitous Torsional Motions in Type II Spicules
Authors: De Pontieu, B.; Carlsson, M.; Rouppe van der Voort, L. H. M.;
   Rutten, R. J.; Hansteen, V. H.; Watanabe, H.
Bibcode: 2012ApJ...752L..12D
Altcode: 2012arXiv1205.5006D
  Spicules are long, thin, highly dynamic features that jut out
  ubiquitously from the solar limb. They dominate the interface between
  the chromosphere and corona and may provide significant mass and energy
  to the corona. We use high-quality observations with the Swedish 1
  m Solar Telescope to establish that so-called type II spicules are
  characterized by the simultaneous action of three different types of
  motion: (1) field-aligned flows of order 50-100 km s<SUP>-1</SUP>,
  (2) swaying motions of order 15-20 km s<SUP>-1</SUP>, and (3) torsional
  motions of order 25-30 km s<SUP>-1</SUP>. The first two modes have been
  studied in detail before, but not the torsional motions. Our analysis
  of many near-limb and off-limb spectra and narrowband images using
  multiple spectral lines yields strong evidence that most, if not all,
  type II spicules undergo large torsional modulation and that these
  motions, like spicule swaying, represent Alfvénic waves propagating
  outward at several hundred km s<SUP>-1</SUP>. The combined action
  of the different motions explains the similar morphology of spicule
  bushes in the outer red and blue wings of chromospheric lines, and
  needs to be taken into account when interpreting Doppler motions to
  derive estimates for field-aligned flows in spicules and determining
  the Alfvénic wave energy in the solar atmosphere. Our results also
  suggest that large torsional motion is an ingredient in the production
  of type II spicules and that spicules play an important role in the
  transport of helicity through the solar atmosphere.

Title: Chromospheric backradiation in ultraviolet continua and Hα
Authors: Rutten, R. J.; Uitenbroek, H.
Bibcode: 2012A&A...540A..86R
Altcode: 2012arXiv1203.0396R
  A recent paper states that ultraviolet backradiation from the solar
  transition region and upper chromosphere strongly affects the degree of
  ionization of minority stages at the top of the photosphere, i.e., in
  the temperature minimum of the one-dimensional static model atmospheres
  presented in that paper. We show that this claim is incompatible with
  observations and we demonstrate that the pertinent ionization balances
  are instead dominated by outward photospheric radiation, as in older
  static models. We then analyze the formation of Hα in the above model
  and show that it has significant backradiation across the opacity gap
  by which Hα differs from other strong scatttering lines.

Title: Graphical introduction to chromospheric line formation
Authors: Rutten, Rob
Bibcode: 2012decs.confE.110R
Altcode:
  The basics of chromospheric line formation theory were laid out
  in the 1960s and 1970s by e.g., Thomas, Avrett, Hummer, Jefferies,
  Mihalas, Shine, Milkey. Since then there has been a long silence,
  without much progress in understanding the chromosphere or its
  diagnostics. At present, the situation changes thanks to better
  ground-based observing, space-based monitoring, and increasingly
  realistic numerical simulations. There is a now a strong need to revamp
  classical one-dimensional static modeling as basis for chromospheric
  line interpretation into 3D dynamic understanding of the major
  diagnostics, including IRIS's Mg II h&amp;k. In this introduction I
  aim to explain the old wisdom in tutorial fashion, using cartoons and
  graphs as means towards an intuitive grasp of fads and fallacies of
  chromospheric line formation.

Title: Ellerman Bombs at High Resolution. I. Morphological Evidence
    for Photospheric Reconnection
Authors: Watanabe, Hiroko; Vissers, Gregal; Kitai, Reizaburo; Rouppe
   van der Voort, Luc; Rutten, Robert J.
Bibcode: 2011ApJ...736...71W
Altcode: 2011arXiv1105.4008W
  High-resolution imaging-spectroscopy movies of solar active region NOAA
  10998 obtained with the Crisp Imaging Spectropolarimeter at the Swedish
  1-m Solar Telescope show very bright, rapidly flickering, flame-like
  features that appear intermittently in the wings of the Balmer Hα line
  in a region with moat flows and likely some flux emergence. They show
  up at regular Hα blue-wing bright points that outline the magnetic
  network, but flare upward with much larger brightness and distinct "jet"
  morphology seen from aside in the limbward view of these movies. We
  classify these features as Ellerman bombs and present a morphological
  study of their appearance at the unprecedented spatial, temporal, and
  spectral resolution of these observations. The bombs appear along the
  magnetic network with footpoint extents up to 900 km. They show apparent
  travel away from the spot along the pre-existing network at speeds
  of about 1 km s<SUP>-1</SUP>. The bombs flare repetitively with much
  rapid variation at timescales of seconds only, in the form of upward
  jet-shaped brightness features. These reach heights of 600-1200 km and
  tend to show blueshifts; some show bi-directional Doppler signature
  and some seem accompanied with an Hα surge. They are not seen in the
  core of Hα due to shielding by overlying chromospheric fibrils. The
  network where they originate has normal properties. The morphology of
  these jets strongly supports deep-seated photospheric reconnection of
  emergent or moat-driven magnetic flux with pre-existing strong vertical
  network fields as the mechanism underlying the Ellerman bomb phenomenon.

Title: Quiet-Sun imaging asymmetries in Na I D<SUB>1</SUB> compared
    with other strong Fraunhofer lines
Authors: Rutten, R. J.; Leenaarts, J.; Rouppe van der Voort, L. H. M.;
   de Wijn, A. G.; Carlsson, M.; Hansteen, V.
Bibcode: 2011A&A...531A..17R
Altcode: 2011arXiv1104.4307R
  Imaging spectroscopy of the solar atmosphere using the Na I
  D<SUB>1</SUB> line yields marked asymmetry between the blue and
  red line wings: sampling a quiet-Sun area in the blue wing displays
  reversed granulation, whereas sampling in the red wing displays normal
  granulation. The Mg I b<SUB>2</SUB> line of comparable strength does
  not show this asymmetry, nor does the stronger Ca II 8542 Å line. We
  demonstrate the phenomenon with near-simultaneous spectral images in
  Na I D<SUB>1</SUB>, Mg I b<SUB>2</SUB>, and Ca II 8542 Å from the
  Swedish 1-m Solar Telescope. We then explain it with line-formation
  insights from classical 1D modeling and with a 3D magnetohydrodynamical
  simulation combined with NLTE spectral line synthesis that permits
  detailed comparison with the observations in a common format. The
  cause of the imaging asymmetry is the combination of correlations
  between intensity and Dopplershift modulation in granular overshoot
  and the sensitivity to these of the steep profile flanks of the Na
  I D<SUB>1</SUB> line. The Mg I b<SUB>2</SUB> line has similar core
  formation but much wider wings due to larger opacity buildup and
  damping in the photosphere. Both lines obtain marked core asymmetry
  from photospheric shocks in or near strong magnetic concentrations,
  less from higher-up internetwork shocks that produce similar asymmetry
  in the spatially averaged Ca II 8542 Å profile.

Title: The quiet chromosphere. Old wisdom, new insights, future needs
Authors: Rutten, Robert J.
Bibcode: 2010MmSAI..81..565R
Altcode: 2010arXiv1002.1482R; 2010MmSAI..81....1R
  The introduction to this review summarizes chromosphere observation
  with two figures. The first part showcases the historical emphasis
  on the eclipse chromosphere in the development of NLTE line formation
  theory and criticizes 1D modeling. The second part advertises recent
  breakthroughs after many decades of standstill. The third part discusses
  what may or should come next.

Title: Waves in the chromosphere: observations
Authors: Rutten, R. J.
Bibcode: 2010arXiv1012.1196R
Altcode:
  I review the literature on observational aspects of waves in the solar
  chromosphere in the first part of this contribution. High-frequency
  waves are invoked to build elaborate cool-star chromosphere heating
  theories but have not been detected decisively so far, neither
  as magnetic modes in network elements nor as acoustic modes in
  below-the-canopy internetwork regions. Three-minute upward-propagating
  acoustic shocks are thoroughly established through numerical
  simulation as the cause of intermittent bright internetwork grains,
  but their pistoning and their role in the low-chromosphere energy
  budget remain in debate. Three-minute wave interaction with magnetic
  canopies is a newer interest, presently progressing through numerical
  simulation. Three-minute umbral flashes and running penumbral waves seem
  a similar acoustic-shock phenomenon awaiting numerical simulation. The
  low-frequency network Doppler modulation remains enigmatic. In
  the second part, I address low-frequency ultraviolet brightness
  variations of the internetwork chromosphere in more detail. They
  contribute about half of the internetwork brightness modulation and
  presumably figure in cool-star basal flux. They appear to be a mixture
  of inverse-contrast granular overshoot at small scales and gravity-wave
  interference at mesogranular scales. I present TRACE evidence for the
  latter interpretation, and speculate that the low-frequency brightness
  minima map canopy heights.

Title: The Irkutsk Barium filter for narrow-band wide-field
    high-resolution solar images at the Dutch Open Telescope
Authors: Hammerschlag, Robert H.; Skomorovsky, Valery I.; Bettonvil,
   Felix C. M.; Kushtal, Galina I.; Olshevsky, Vyacheslav L.; Rutten,
   Robert J.; Jägers, Aswin P. L.; Sliepen, Guus; Snik, Frans
Bibcode: 2010SPIE.7735E..85H
Altcode: 2010SPIE.7735E.265H
  A wide-field birefringent filter for the barium II line at 455.4nm is
  developed in Irkutsk. The Barium line is excellent for Doppler-shift
  measurements because of low thermal line-broadening and steep
  flanks of the line profile. The filter width is 0.008nm and the
  filter is tunable over 0.4nm through the whole line and far enough
  in the neighboring regions. A fast tuning system with servomotor is
  developed at the Dutch Open Telescope (DOT). Observations are done
  in speckle mode with 10 images per second and Keller-VonDerLühe
  reconstruction using synchronous images of a nearby bluecontinuum
  channel at 450.5nm. Simultaneous observation of several line positions,
  typically 3 or 5, are made with this combination of fast tuning and
  speckle. All polarizers are birefringent prisms which largely reduced
  the light loss compared to polarizing sheets. The advantage of this
  filter over Fabry-Perot filters is its wide field due to a large
  permitted entrance angle and no need of polishing extremely precise
  surfaces. The BaII observations at the DOT occur simultaneously with
  those of a fast-tunable birefringent H-alpha filter. This gives the
  unique possibility of simultaneous speckle-reconstructed observations
  of velocities in photosphere (BaII) and chromosphere (H-alpha).

Title: Solar Spectroscopy and (Pseudo-)Diagnostics of the Solar
    Chromosphere
Authors: Rutten, Robert J.
Bibcode: 2010ASSP...17..163R
Altcode: 2009arXiv0905.2623R; 2010rast.conf..163R; 2010rasp.book..163R
  I first review trends in current solar spectrometry and then
  concentrate on comparing various spectroscopic diagnostics of the
  solar chromosphere. Some are actually not at all chromospheric but
  just photospheric or clapotispheric and do not convey information on
  chromospheric heating, even though this is often assumed. Balmer Hα
  is the principal displayer of the closed-field chromosphere, but it
  is unclear how chromospheric fibrils gain their large Hα opacity. The
  open-field chromosphere seems to harbor most if not all coronal heating
  and solar wind driving, but is hardly seen in optical diagnostics.

Title: The Quiet Solar Atmosphere Observed and Simulated in Na
    I D<SUB>1</SUB>
Authors: Leenaarts, J.; Rutten, R. J.; Reardon, K.; Carlsson, M.;
   Hansteen, V.
Bibcode: 2010ApJ...709.1362L
Altcode: 2009arXiv0912.2206L
  The Na I D<SUB>1</SUB> line in the solar spectrum is sometimes
  attributed to the solar chromosphere. We study its formation in
  quiet-Sun network and internetwork. We first present high-resolution
  profile-resolved images taken in this line with the imaging
  spectrometer Interferometric Bidimensional Spectrometer at the Dunn
  Solar Telescope and compare these to simultaneous chromospheric images
  taken in Ca II 8542 Å and Hα. We then model Na I D<SUB>1</SUB>
  formation by performing three-dimensional (3D) non-local
  thermodynamic equilibrium profile synthesis for a snapshot from a
  3D radiation-magnetohydrodynamics simulation. We find that most Na I
  D<SUB>1</SUB> brightness is not chromospheric but samples the magnetic
  concentrations that make up the quiet-Sun network in the photosphere,
  well below the height where they merge into chromospheric canopies,
  with aureoles from 3D resonance scattering. The line core is sensitive
  to magneto-acoustic shocks in and near magnetic concentrations, where
  shocks occur deeper than elsewhere, and may provide evidence of heating
  deep within magnetic concentrations.

Title: Magnetic Coupling between the Interior and Atmosphere of
    the Sun
Authors: Hasan, S. S.; Rutten, R. J.
Bibcode: 2010ASSP...19.....H
Altcode: 2010mcia.conf.....H
  No abstract at ADS

Title: Dual-Line Spectral Imaging of the Chromosphere
Authors: Cauzzi, G.; Reardon, K.; Rutten, R. J.; Tritschler, A.;
   Uitenbroek, H.
Bibcode: 2010ASSP...19..513C
Altcode: 2010mcia.conf..513C
  Hα filtergrams are notoriously difficult to interpret, "beautiful
  to view but not fit for analysis." We try to remedy this by using
  the IBIS bi-dimensional spectrometer at the Dunn Solar Telescope at
  NSO/Sacramento Peak to compare the quiet-sun chromosphere observed in
  Hα to what is observed simultaneously in Ca II 854.2 nm, sampling both
  lines with high angular and spectral resolution and extended coverage
  of space, time, and wavelength. Per (x, y, t) pixel we measured the
  intensity and Dopplershift of the minimum of each line's profile at
  that pixel, as well as the width of their inner chromospheric cores. A
  paper submitted to A&amp;A (December 2008) compares these measurements
  in detail.

Title: The solar chromosphere at high resolution with
    IBIS. IV. Dual-line evidence of heating in chromospheric network
Authors: Cauzzi, G.; Reardon, K.; Rutten, R. J.; Tritschler, A.;
   Uitenbroek, H.
Bibcode: 2009A&A...503..577C
Altcode: 2009arXiv0906.2083C
  The structure and energy balance of the solar chromosphere remain
  poorly known. We used the imaging spectrometer IBIS at the Dunn Solar
  Telescope to obtain fast-cadence, multi-wavelength profile sampling
  of Hα and Ca ii 854.2 nm over a sizable two-dimensional field of view
  encompassing quiet-Sun network. We provide a first inventory of how the
  quiet chromosphere appears in these two lines by comparing basic profile
  measurements in the form of image displays, temporal-average displays,
  time slices, and pixel-by-pixel correlations. We find that the two lines
  can be markedly dissimilar in their rendering of the chromosphere,
  but that, nevertheless, both show evidence of chromospheric heating,
  particularly in and around network: Hα in its core width and Ca ii
  854.2 nm in its brightness. We discuss venues for improved modeling.

Title: Dynamic Lyα jets
Authors: Koza, J.; Rutten, R. J.; Vourlidas, A.
Bibcode: 2009A&A...499..917K
Altcode: 2008arXiv0807.4889K
  Context: The solar chromosphere and transition region are highly
  structured and complex regimes. A recent breakthrough has been
  the identification of dynamic fibrils observed in Hα as caused
  by field-aligned magnetoacoustic shocks. <BR />Aims: We seek to
  find whether such dynamic fibrils are also observed in Lyα. <BR
  />Methods: We used a brief sequence of four high-resolution Lyα
  images of the solar limb taken by the Very high Angular resolution
  ULtraviolet Telescope (VAULT), which displays many extending and
  retracting Lyα jets. We measured their top trajectories and fitted
  parabolas to the 30 best-defined ones. <BR />Results: Most jet tops move
  supersonically. Half of them decelerate, sometimes superballistically,
  the others accelerate. This bifurcation may arise from incomplete
  sampling of recurrent jets. <BR />Conclusions: The similarities between
  dynamic Lyα jets and Hα fibrils suggest that the magnetoacoustic
  shocks causing dynamic Hα fibrils also affect dynamic Lyα jets.

Title: Explanation of the activity sensitivity of Mn I 5394.7 Å
Authors: Vitas, N.; Viticchiè, B.; Rutten, R. J.; Vögler, A.
Bibcode: 2009A&A...499..301V
Altcode: 2008arXiv0811.3555V
  There is a long-standing debate why the Mn i 5394.7 Å line in the
  solar irradiance spectrum brightens more at higher activity than
  other photospheric lines. The claim that this is caused by spectral
  interlocking to chromospheric emission in the Mg ii h &amp; k lines
  is disputed. In this paper we settle this issue, using classical
  one-dimensional modeling for demonstration and modern three-dimensional
  MHD simulation for verification and analysis. The unusual sensitivity
  of the Mn i 5394.7 Å line to solar activity is due to its excessive
  hyperfine structure. This overrides the thermal and granular Doppler
  smearing through which the other, narrower, photospheric lines lose
  such sensitivity. We take the nearby Fe i 5395.2 Å line as example
  of the latter, and analyze the formation of both lines in detail to
  demonstrate and explain the granular Doppler brightening which affects
  all narrow photospheric lines. Neither the chromosphere nor Mg ii h
  &amp; k emission play a role, nor is it correct to describe the activity
  sensitivity of Mn i 5394.7 Å in terms of plage models with outward
  increasing temperature contrast. The Mn i 5394.7 Å line represents a
  proxy diagnostic of strong-field magnetic concentrations in the deep
  solar photosphere comparable to the G band and the blue wing of Hα,
  but not a better one than these. The Mn i lines are more promising as
  diagnostics of weak fields in high-resolution Stokes polarimetry.

Title: Hα as a Chromospheric Diagnostic
Authors: Rutten, R. J.
Bibcode: 2008ASPC..397...54R
Altcode:
  I first illustrate with images from the Dutch Open Telescope (DOT)
  that Hα is the principal diagnostic of the solar chromosphere. The
  DOT movies at http://dot.astro.uu.nl demonstrate this fact even more
  vividly. <P />I then summarize, on the basis of the recent numerical
  simulations by <P />Leenaarts et al. (2007), <P />why Halpha; is
  such an omnipresent diagnostic of the chromosphere. The ubiquity of
  Hα fibrils in both hot and cool gas is due to (i)- the presence of
  shocks everywhere, guided by the magnetic field into dynamic fibrils
  near the network and pushing the canopy and transition region upward
  in weaker-field internetwork regions, (ii)- the large rate difference
  between the fast hydrogen ionization/recombination balancing in hot
  shocks and the slow balancing in cool post-shock gas, and (iii)- the
  large excitation energy of Hα's nis2 lower level, causing strong
  coupling to the ion population. These three facts combine to cause
  appreciable Hα opacity throughout the chromosphere, enormously in
  excess of instantaneous Saha-Boltzmann partitioning in cool post-shock
  gas. Thus, sluggish post-shock recombination causes Hα to be visible
  everywhere. <P />Finally, I address Hα observing. Since Hinode's
  Hα imaging is affected by bubbles and limited in cadence, the DOT
  may serve as a complementary facility furnishing profile-sampling Hα
  image sequences at the same 0.3 arcsec angular resolution as Hinode
  whenever the La Palma seeing is good. However, imminent loss of DOT
  funding requires outside financing of an on-site observer for DOT
  utilization in co-pointed joint observing.

Title: DOT Tomography of the Solar Atmosphere VII. Chromospheric
    Response to Acoustic Events
Authors: Rutten, R. J.; van Veelen, B.; Sütterlin, P.
Bibcode: 2008SoPh..251..533R
Altcode: 2008arXiv0801.0374R; 2008SoPh..tmp...28R
  We use synchronous movies from the Dutch Open Telescope sampling the G
  band, Ca II H, and Hα with five-wavelength profile sampling to study
  the response of the chromosphere to acoustic events in the underlying
  photosphere. We first compare the visibility of the chromosphere in
  Ca II H and Hα, demonstrate that studying the chromosphere requires
  Hα data, and summarize recent developments in understanding why this
  is so. We construct divergence and vorticity maps of the photospheric
  flow field from the G-band images and locate specific events through
  the appearance of bright Ca II H grains. The reaction of the Hα
  chromosphere is diagnosed in terms of brightness and Doppler shift. We
  show and discuss three particular cases in detail: a regular acoustic
  grain marking shock excitation by granular dynamics, a persistent
  flasher, which probably marks magnetic-field concentration, and an
  exploding granule. All three appear to buffet overlying fibrils, most
  clearly in Dopplergrams. Although our diagnostic displays to dissect
  these phenomena are unprecedentedly comprehensive, adding even more
  information (photospheric Doppler tomography and magnetograms along
  with chromospheric imaging and Doppler mapping in the ultraviolet)
  is warranted.

Title: Dynamic Fibrils in Ly-alpha
Authors: Koza, J.; Rutten, R. J.; Vourlidas, A.; Suetterlin, P.
Bibcode: 2008ESPM...12.2.16K
Altcode:
  We have detected dynamic fibrils (DFs) in Ly-alpha filtergrams taken
  with the rocket-borne Very high Angular resolution ULtraviolet Telescope
  (VAULT). Although the data consist of only a 1-min sequence of 4
  images taken near the solar limb during the second VAULT flight, they
  enable us to identify and study the time evolution of over 50 DFs. Most
  show parabolic trajectories in their angular extent, with supersonic
  maximum velocities. The measured decelerations vary from sub-ballistic
  to super-ballistic. The similarities with DFs seen in Halpha suggest a
  common cause, possibly the presence of hot transition-region interfaces
  around cool oscillation-fed jets.

Title: Concluding remarks
Authors: Rutten, R. J.
Bibcode: 2008ESPM...12..7.1R
Altcode:
  No abstract at ADS

Title: On the solar abundance of indium
Authors: Vitas, N.; Vince, I.; Lugaro, M.; Andriyenko, O.; Gošić,
   M.; Rutten, R. J.
Bibcode: 2008MNRAS.384..370V
Altcode: 2008MNRAS.tmp...25V; 2007arXiv0711.2166V
  The generally adopted value for the solar abundance of indium is over
  six times higher than the meteoritic value. We address this discrepancy
  through numerical synthesis of the 451.13-nm line on which all indium
  abundance studies are based, both for the quiet Sun and the sunspot
  umbra spectrum, employing standard atmosphere models and accounting
  for hyperfine structure and Zeeman splitting in detail. The results,
  as well as a re-appraisal of indium nucleosynthesis, suggest that
  the solar indium abundance is close to the meteoritic value, and
  that some unidentified ion line causes the 451.13-nm feature in the
  quiet-Sun spectrum.

Title: Search for photospheric footpoints of quiet Sun transition
    region loops
Authors: Sánchez Almeida, J.; Teriaca, L.; Sütterlin, P.; Spadaro,
   D.; Schühle, U.; Rutten, R. J.
Bibcode: 2007A&A...475.1101S
Altcode: 2007arXiv0709.3451S
  Context: The footpoints of quiet Sun Transition Region (TR) loops
  do not seem to coincide with the photospheric magnetic structures
  appearing in traditional low-sensitivity magnetograms. <BR />Aims: We
  look for the so-far unidentified photospheric footpoints of TR loops
  using G-band bright points (BPs) as proxies for photospheric magnetic
  field concentrations. <BR />Methods: We compare TR measurements with
  SoHO/SUMER and photospheric magnetic field observations obtained with
  the Dutch Open Telescope. <BR />Results: Photospheric BPs are associated
  with bright TR structures, but they seem to avoid the brightest parts
  of the structure. BPs appear in regions that are globally redshifted,
  but they avoid extreme velocities. TR explosive events are not clearly
  associated with BPs. <BR />Conclusions: The observations are not
  inconsistent with the BPs being footpoints of TR loops, although we
  have not succeeded to uniquely identify particular BPs with specific
  TR loops.

Title: Non-equilibrium hydrogen ionization in 2D simulations of the
    solar atmosphere
Authors: Leenaarts, J.; Carlsson, M.; Hansteen, V.; Rutten, R. J.
Bibcode: 2007A&A...473..625L
Altcode: 2007arXiv0709.3751L
  Context: The ionization of hydrogen in the solar chromosphere and
  transition region does not obey LTE or instantaneous statistical
  equilibrium because the timescale is long compared with important
  hydrodynamical timescales, especially of magneto-acoustic shocks. Since
  the pressure, temperature, and electron density depend sensitively on
  hydrogen ionization, numerical simulation of the solar atmosphere
  requires non-equilibrium treatment of all pertinent hydrogen
  transitions. The same holds for any diagnostic application employing
  hydrogen lines. <BR />Aims: To demonstrate the importance and to
  quantify the effects of non-equilibrium hydrogen ionization, both
  on the dynamical structure of the solar atmosphere and on hydrogen
  line formation, in particular Hα. <BR />Methods: We implement an
  algorithm to compute non-equilibrium hydrogen ionization and its
  coupling into the MHD equations within an existing radiation MHD code,
  and perform a two-dimensional simulation of the solar atmosphere from
  the convection zone to the corona. <BR />Results: Analysis of the
  simulation results and comparison to a companion simulation assuming
  LTE shows that: a) non-equilibrium computation delivers much smaller
  variations of the chromospheric hydrogen ionization than for LTE. The
  ionization is smaller within shocks but subsequently remains high in
  the cool intershock phases. As a result, the chromospheric temperature
  variations are much larger than for LTE because in non-equilibrium,
  hydrogen ionization is a less effective internal energy buffer. The
  actual shock temperatures are therefore higher and the intershock
  temperatures lower. b) The chromospheric populations of the hydrogen
  n = 2 level, which governs the opacity of Hα, are coupled to the
  ion populations. They are set by the high temperature in shocks
  and subsequently remain high in the cool intershock phases. c)
  The temperature structure and the hydrogen level populations differ
  much between the chromosphere above photospheric magnetic elements
  and above quiet internetwork. d) The hydrogen n = 2 population and
  column density are persistently high in dynamic fibrils, suggesting
  that these obtain their visibility from being optically thick in Hα
  also at low temperature. <P />Movie and Appendix A are only available
  in electronic form at http://www.aanda.org

Title: Chromospheric and Transition-Region Dynamics in Plage
Authors: de Wijn, A. G.; de Pontieu, B.; Rutten, R. J.
Bibcode: 2007ASPC..368..137D
Altcode:
  We study the dynamical interaction of the solar chromosphere with
  the transition region in mossy and non-mossy active-region plage. We
  carefully align image sequences taken with the Transition Region And
  Coronal Explorer (TRACE) in the ultraviolet passbands around 1550, 1600,
  and 1700 Å and the extreme ultraviolet passbands at 171 and 195 Å. We
  compute Fourier phase-difference spectra that are spatially averaged
  separately over mossy and non-mossy plage to study temporal modulations
  as a function of temporal frequency. The 1550 versus 171 Å comparison
  shows zero phase difference in non-mossy plage. In mossy plage, the
  phase differences between all UV and EUV passbands show pronounced
  upward trends with increasing frequency, which abruptly changes
  into zero phase difference beyond 4 -- 6 mHz. The phase difference
  between the 171 and 195 Å sequences exhibits a shallow dip below 3
  mHz and then also turns to zero phase difference beyond this value. We
  attribute the various similarities between the UV and EUV diagnostics
  that are evident in the phase-difference diagrams to the contribution
  of the C IV resonance lines in the 1550 and 1600 Å passbands. The
  strong upward trend at the lower frequencies indicates the presence of
  upward-traveling disturbances. It points to correspondence between the
  lower chromosphere and the upper transition region, perhaps by slow-mode
  magnetosonic disturbances, or by a connection between chromospheric and
  coronal heating mechanisms. The transition from this upward trend to
  zero phase difference at higher frequencies is due to the intermittent
  obscuration by fibrils that occult the foot points of hot loops,
  which are bright in the EUV and C IV lines, in oscillatory manner.

Title: ESMN in Memoriam (1998 -- 2006)
Authors: Rutten, R. J.
Bibcode: 2007ASPC..368...21R
Altcode:
  The EC-FP5 European Solar Magnetism Network (ESMN) was terminated during
  this conference. Together with its FP4 predecessor, the European Solar
  Magnetometry Network (ESMN), it funded 22 postdoc and 9 graduate-student
  appointments at nine solar physics groups in Western Europe, it enhanced
  Europe-wide collaboration in solar physics, and it contributed to the
  integration of East-European groups in West-European enterprises. Its
  unfortunate demise results from lack of further fortune in the FP6
  lottery. The FP6-funded Utrecht-Stockholm-Oslo graduate school in
  solar physics represents offspring, the FP6 Solaire network is a
  partial replacement, and the EAST undertaking and pledge to build an
  EST is a most worthy FP7 stake. The EC's policy shifts from postdoc
  to predoc funding and from requiring (too) small to requiring (too)
  large consortia are criticized.

Title: Aperture Increase Options for the Dutch Open Telescope
Authors: Hammerschlag, R. H.; Bettonvil, F. C. M.; Jägers, A. P. L.;
   Rutten, R. J.
Bibcode: 2007ASPC..368..573H
Altcode: 2007astro.ph..3638H
  This paper is an invitation to the international community to
  participate in the usage and a substantial upgrade of the Dutch Open
  Telescope on La Palma (DOT, http://dot.astro.uu.nl). <P />We first
  give a brief overview of the approach, design, and current science
  capabilities of the DOT. It became a successful 0.2-arcsec-resolution
  solar movie producer through its combination of (i) an excellent
  site, (ii) effective wind flushing through the fully open design and
  construction of both the 45-cm telescope and the 15-m support tower,
  (iii) special designs which produce extraordinary pointing stability of
  the tower, equatorial mount, and telescope, (iv) simple and excellent
  optics with minimum wavefront distortion, and (v) large-volume
  speckle reconstruction including narrow-band processing. The DOT's
  multi-camera multi-wavelength speckle imaging system samples the
  solar photosphere and chromosphere simultaneously in various optical
  continua, the G band, Ca II H (tunable throughout the blue wing),
  and Hα (tunable throughout the line). The resulting DOT data sets
  are all public. The DOT database (http://dotdb.phys.uu.nl/DOT)
  now contains many tomographic image sequences with 0.2-0.3 arcsec
  resolution and up to multi-hour duration. You are welcome to pull them
  over for analysis. <P />The main part of this contribution outlines
  DOT upgrade designs implementing larger aperture. The motivation
  for aperture increase is the recognition that optical solar physics
  needs the substantially larger telescope apertures that became useful
  with the advent of adaptive optics and viable through the DOT's open
  principle, both for photospheric polarimetry at high resolution and
  high sensitivity and for chromospheric fine-structure diagnosis at
  high cadence and full spectral sampling. <P />Our upgrade designs for
  the DOT are presented in an incremental sequence of five options of
  which the simplest (Option I) achieves 1.4 m aperture using the present
  tower, mount, fold-away canopy, and multi-wavelength speckle imaging
  and processing systems. The most advanced (Option V) offers unblocked
  2.5 m aperture in an off-axis design with a large canopy, a wide 30-m
  high support tower, and image transfer to a groundbased optics lab for
  advanced instrumentation. All five designs employ adaptive optics. The
  important advantages of fully open, wind-transparent and wind-flushed
  structure, polarimetric constancy, and absence of primary-image rotation
  remain. All designs are relatively cheap through re-using as much of
  the existing DOT hardware as possible. <P />Realization of an upgrade
  requires external partnership(s). This report about DOT upgrade options
  therefore serves also as initial documentation for potential partners.

Title: Observing the Solar Chromosphere
Authors: Rutten, R. J.
Bibcode: 2007ASPC..368...27R
Altcode: 2007astro.ph..3637R
  This review is split into two parts: one on chromospheric line formation
  in answer to the frequent question ``where is my line formed'',
  and one presenting state-of-the-art imagery of the chromosphere. In
  the first part I specifically treat the formation of the Na D lines,
  Ca II H&amp;K, and Hα. In the second I show DOT, IBIS, VAULT, and
  TRACE images as evidence that the chromosphere consists of fibrils of
  intrinsically different types. The straight-up ones are hottest. The
  slanted ones are filled by shocks and likely possess thin transition
  sheaths to coronal plasma. The ones hovering horizontally over
  ``clapotispheric'' cell interiors outline magnetic canopies and are
  buffeted by shocks, most violently in the quietest regions. <P />In
  the absence of integral-field ultraviolet spectrometry, Hα remains
  the principal chromosphere diagnostic. The required fast-cadence
  profile-sampling imaging is an important quest for new telescope
  technology.

Title: The Physics of Chromospheric Plasmas
Authors: Heinzel, P.; Dorotovič, I.; Rutten, R. J.
Bibcode: 2007ASPC..368.....H
Altcode:
  No abstract at ADS

Title: Fourier Analysis of Active-Region Plage
Authors: de Wijn, A. G.; De Pontieu, B.; Rutten, R. J.
Bibcode: 2007ApJ...654.1128D
Altcode: 2007arXiv0706.2014D
  We study the dynamical interaction of the solar chromosphere with
  the transition region in mossy and nonmossy active-region plage. We
  carefully align image sequences taken with the Transition Region And
  Coronal Explorer (TRACE) in the ultraviolet passbands around 1550,
  1600, and 1700 Å and the extreme ultraviolet passbands at 171 and 195
  Å. We compute Fourier phase-difference spectra that are spatially
  averaged separately over mossy and nonmossy plage to study temporal
  modulations as a function of temporal frequency. The 1550 versus 171
  Å comparison shows zero phase difference in nonmossy plage. In mossy
  plage, the phase differences between all UV and EUV passbands show
  pronounced upward trends with increasing frequency, which abruptly
  changes into zero phase difference beyond 4-6 mHz. The phase difference
  between the 171 and 195 Å sequences exhibits a shallow dip below 3
  mHz and then also turns to zero phase difference beyond this value. We
  attribute the various similarities between the UV and EUV diagnostics
  that are evident in the phase-difference diagrams to the contribution
  of the C IV resonance lines in the 1550 and 1600 Å passbands. The
  strong upward trend at the lower frequencies indicates the presence of
  upward-traveling disturbances. It points to correspondence between the
  lower chromosphere and the upper transition region, perhaps by slow-mode
  magnetosonic disturbances, or by a connection between chromospheric and
  coronal heating mechanisms. The transition from this upward trend to
  zero phase difference at higher frequencies is due to the intermittent
  obscuration by fibrils that occult the footpoints of hot loops, which
  are bright in the EUV and C IV lines, in an oscillatory manner.

Title: The Ba II 4554 / Hβ Imaging Polarimeter for the Dutch Open
    Telescope
Authors: Snik, F.; Bettonvil, F. C. M.; Jägers, A. P. L.;
   Hammerschlag, R. H.; Rutten, R. J.; Keller, C. U.
Bibcode: 2006ASPC..358..205S
Altcode:
  In order to expand the high-resolution, multi-wavelength imaging
  capabilities of the Dutch Open Telescope (DOT), an additional
  polarimetric channel based on a 80 mÅ tunable Lyot filter for Ba
  II 4554 and Hβ has been designed and constructed. The large atomic
  mass and the resulting steep line wings, make Ba II 4554 particularly
  suitable for the creation of photospheric Dopplergrams and Stokes-V
  magnetograms. The line also yields a significant degree of linear
  (scattering) polarization for observations near the limb of the Sun,
  which is modified by both horizontal and vertical weak-field topologies
  through the Hanle effect and hyperfine-structure level crossing. The
  polarimeter is based on liquid crystal variable retarders (LCVRs)
  as polarization modulators in combination with the Lyot filter's
  entrance polarizer. The tunability of the LCVRs is exploited to enable
  specific wavelength calibration, selection of the reference frame of
  linear polarization, and optimization of instrumental polarization
  cross-talk, which for the DOT is constant in time. With the future
  Ba II 4554 photospheric magnetograms, we expect to be able to discern
  magnetic structures of about 150 km with field strengths down to 100 G,
  and that Hanle-type observations can be performed at a resolution of
  about 1 arcsec. The range of applicability of Hβ imaging polarimetry
  has to be explored after installation.

Title: Magnetic Patches in Internetwork Areas
Authors: de Wijn, A. G.; Rutten, R. J.; Haverkamp, E. M. W. P.;
   Sütterlin, P.
Bibcode: 2006ASPC..354...20D
Altcode:
  We present a study of internetwork magnetic elements that appear as
  bright points in G-band (photosphere) and Ca II H (low chromosphere)
  image sequences from the Dutch Open Telescope. Many bright points
  appear intermittently in groups of long-lived structures that we call
  ``magnetic patches''. We develop an algorithm for the identification
  of bright points and magnetic patches. The average internetwork bright
  point lifetimes is measured to be 3.5 minutes in the G band, and 4.3
  minutes in the Ca II H. We find an internetwork bright point number
  density of 0.02 Mm^{-2} in the G-band sequence and 0.05 Mm^{-2} in
  the Ca II H sequence. The bright points show a bimodal distribution
  of the frame-to-frame horizontal velocities, with a peak at 0 km
  s^{-1} and a wide hump centered around 1.2 km s^{-1}. The patches
  last much longer than granular time scales (about nine hours) and
  outline cell-like structures on mesogranular scale. We conclude that
  transient internetwork bright points trace the locations of strong
  magnetic fields that exist before the bright point appears and remain
  after it disappears.

Title: Fourier analysis of chromospheric and transition region
    emission above active region plage
Authors: de Wijn, A. G.; de Pontieu, B.; Rutten, R. J.
Bibcode: 2006AGUFMSH23B0364D
Altcode:
  We study the dynamical interaction of the solar chromosphere with the
  transition region (TR) in mossy and non-mossy active region plage, and
  find evidence for correlated brightness changes or upward travelling
  disturbances between the low chromosphere and the upper transition
  region. We carefully align image sequences taken with the Transition
  Region and Coronal Explorer (TRACE) in the ultraviolet passbands around
  1550, 1600 and 1700 Å\ (indicative of low chromosphere and low TR)
  and the extreme ultraviolet passbands at 171 and 195 Å\ (indicative of
  upper transition region). We compute Fourier phase-difference spectra
  that are spatially averaged separately over mossy and non-mossy plage to
  study temporal modulations as a function of temporal frequency. We find
  that in non-mossy plage there is zero phase difference between 1550 Å\
  and 171 Å. In mossy plage, the phase differences between all UV and EUV
  passbands show pronounced upward trends with increasing frequency, which
  abruptly changes into zero phase differences for frequencies beyond 4-6
  mHz. The phase difference between the 171 and 195 Å\ sequences exhibits
  a shallow dip below 3 mHz and then also turns to zero phase difference
  beyond this value. We attribute some of the various similarities between
  the UV and EUV diagnostics that are evident in the phase-difference
  diagrams to the contribution of the C IV resonance lines in the 1550 and
  1600 Å\ passbands. The strong upward trend at lower frequencies in the
  phase difference between all UV passbands (including 1700 Å) and 171
  Å\ indicates the presence of upward travelling disturbances. Since
  1700 Å\ does not contain C IV emission (low TR), this points to a
  correlation between brightness changes in the lower chromosphere and
  the upper TR, perhaps by slow-mode disturbances, or by a connection
  between chromospheric and coronal heating mechanisms. We find that
  such correlated brightness changes first occur in the low chromosphere,
  and are followed about 400 s later in the upper TR. The transition from
  the upward trend in phase difference at low frequencies to zero phase
  difference at higher frequencies is due to the intermittent obscuration
  by fibrils. These chromospheric jets occult the footpoints of hot loops,
  which are bright in the EUV and C IV lines, in oscillatory manner.

Title: On the Nature of the Solar Chromosphere
Authors: Rutten, R. J.
Bibcode: 2006ASPC..354..276R
Altcode: 2007astro.ph..1379R
  DOT high-resolution imagery suggests that only internetwork-spanning
  Hα ``mottles'' constitute the quiet-Sun chromosphere, whereas more
  upright network ``straws'' in ``hedge rows'' reflect transition-region
  conditions.

Title: Tunable H-alpha Lyot filter with advanced servo system and
image processing: instrument design and new scientific results with
    the Dutch Open Telescope
Authors: Bettonvil, Felix C. M.; Hammerschlag, Robert H.; Sütterlin,
   Peter; Rutten, Robert J.; Jägers, Aswin P. L.; Sliepen, Guus
Bibcode: 2006SPIE.6269E..0EB
Altcode: 2006SPIE.6269E..12B
  The Dutch Open Telescope (DOT; http://dot.astro.uu.nl) on La Palma
  is a revolutionary open solar telescope, on an excellent site, on
  top of a transparent tower of steel framework, and uses natural
  air flow to minimize local seeing. The DOT is a high-resolution
  multi-wavelength imager capable of long-duration time series aiming
  at magnetic fine structure, topology and dynamics in the photosphere
  and low- and high chromosphere. In this paper we describe the latest
  addition to the multi-wavelength imaging system: a Lyot H-alpha
  camera channel operating at a wavelength of 656.3 nm, being of major
  interest for high-chromospheric phenomena. The channel is operated
  strictly synchronous with the other channels and all data are speckle
  reconstructed. The channel permits profile sampling and delivers
  Dopplergrams in a 15 second time cadence, up to several hours long
  and adding up to a total data amount of 1.6 Terabyte/day. A dedicated
  computer (DSP, DOT Speckle Processor) has been built for processing
  the data overnight.

Title: A comparison of solar proxy-magnetometry diagnostics
Authors: Leenaarts, J.; Rutten, R. J.; Carlsson, M.; Uitenbroek, H.
Bibcode: 2006A&A...452L..15L
Altcode:
  Aims.We test various proxy-magnetometry diagnostics, i.e., brightness
  signatures of small-scale magnetic elements, for studying magnetic
  field structures in the solar photosphere.<BR /> Methods: .Images are
  numerically synthesized from a 3D solar magneto-convection simulation
  for, respectively, the G band at 430.5 nm, the CN band at 388.3 nm,
  and the blue wings of the H α, H β, Ca ii H, and Ca ii 854.2 nm
  lines.<BR /> Results: .Both visual comparison and scatter diagrams of
  the computed intensity versus the magnetic field strength show that,
  in particular for somewhat spatially extended magnetic elements, the
  blue H α wing presents the best proxy-magnetometry diagnostic, followed
  by the blue wing of H β. The latter yields higher diffraction-limit
  resolution.<BR /> Conclusions: .We recommend using the blue H α wing
  to locate and track small-scale photospheric magnetic elements through
  their brightness appearance.

Title: DOT tomography of the solar atmosphere. VI. Magnetic elements
    as bright points in the blue wing of Hα
Authors: Leenaarts, J.; Rutten, R. J.; Sütterlin, P.; Carlsson, M.;
   Uitenbroek, H.
Bibcode: 2006A&A...449.1209L
Altcode:
  High-resolution solar images taken in the blue wing of the Balmer H
  α line with the Dutch Open Telescope show intergranular magnetic
  elements as strikingly bright features, similar to, but with
  appreciably larger contrast over the surrounding granulation than
  their more familiar manifestation as G-band bright points. Part of
  this prominent appearance is due to low granular contrast, without
  granule/lane brightness reversal as, e.g., in the wings of Ca II H
  &amp; K. We use 1D and 2D radiative transfer modeling and 3D solar
  convection and magnetoconvection simulations to reproduce and explain
  the H α wing images. We find that the blue H α wing obeys near-LTE
  line formation. It appears particularly bright in magnetic elements
  through low temperature gradients. The granulation observed in the blue
  wing of H α has low contrast because of the lack of H α opacity in the
  upper photosphere, Doppler cancellation, and large opacity sensitivity
  to temperature working against source function sensitivity. We conclude
  that the blue H α wing represents a promising proxy magnetometer to
  locate and track isolated intermittent magnetic elements, a better one
  than the G band and the wings of Ca II H &amp; K although less sharp
  at given aperture.

Title: Small Scale Magnetic Elements as Bright Points in the Blue
    Hα Wing
Authors: Leenaarts, J.; Sütterlin, P.; Rutten, R. J.; Carlsson, M.;
   Uitenbroek, H.
Bibcode: 2005ESASP.596E..15L
Altcode: 2005ccmf.confE..15L
  No abstract at ADS

Title: DOT tomography of the solar atmosphere.  IV. Magnetic patches
    in internetwork areas
Authors: de Wijn, A. G.; Rutten, R. J.; Haverkamp, E. M. W. P.;
   Sütterlin, P.
Bibcode: 2005A&A...441.1183D
Altcode: 2007arXiv0706.2008D
  We use G-band and Ca ii H image sequences from the Dutch Open
  Telescope (DOT) to study magnetic elements that appear as bright
  points in internetwork parts of the quiet solar photosphere and
  chromosphere. We find that many of these bright points appear
  recurrently with varying intensity and horizontal motion within
  longer-lived magnetic patches. We develop an algorithm for detection
  of the patches and find that all patches identified last much longer
  than the granulation. The patches outline cell patterns on mesogranular
  scales, indicating that magnetic flux tubes are advected by granular
  flows to mesogranular boundaries. Statistical analysis of the emergence
  and disappearance of the patches points to an average patch lifetime
  as long as 530±50~min (about nine hours), which suggests that the
  magnetic elements constituting strong internetwork fields are not
  generated by a local turbulent dynamo.

Title: The wings of Ca II H and K as solar fluxtube diagnostics
Authors: Sheminova, V. A.; Rutten, R. J.; Rouppe van der Voort,
   L. H. M.
Bibcode: 2005A&A...437.1069S
Altcode:
  We combine high-resolution Ca II H and K spectrograms from the
  Swedish Vacuum Solar Telescope with standard fluxtube modeling to
  derive photospheric temperature and velocity stratifications within
  individual magnetic elements in plage near a sunspot. We find that 1D
  on-axis modeling gives better consistency than spatial averaging over
  flaring-fluxtube geometry. Our best-fit temperature stratifications
  suggest that magnetic elements are close to radiative equilibrium
  throughout their photospheres. Their brightness excess throughout the
  H and K wings compared with the quiet photosphere is primarily due to
  low density, not to mechanical heating. We conclude that the extended
  H and K wings provide excellent fine-structure diagnostics for both
  high-resolution observations and simulations of the solar photosphere.

Title: The temperature gradient in and around solar magnetic fluxtubes
Authors: Sheminova, V. A.; Rutten, R. J.; Rouppe van der Voort,
   L. H. M.
Bibcode: 2005KFNTS...5..110S
Altcode:
  We use spectra covering the outer part of the extended wing of the solar
  Ca II K line observed at high angular resolution with the Swedish Vacuum
  Solar Telescope to test standard solar fluxtube models. The wings of the
  Ca II resonance lines are formed in LTE both with regard to excitation
  (source function) and to ionization (opacity) and, therefore, sample
  temperature stratifications in relatively straightforward fashion. We
  obtain best fits by combining steeper temperature gradients than
  those in the standard models for both the tube inside and the tube
  environment. Similarly steep gradients are also determined from a
  numerical magnetoconvection simulation by the late A. S. Gadun. It
  is found that the energy balance in the individual magnetic elements
  appears to be close to radiative equilibrium throughout the photosphere.

Title: MAO-SIU solar physics collaborations
Authors: Rutten, R. J.
Bibcode: 2005KFNTS...5...11R
Altcode:
  The Kyiv-Utrecht collaboration in solar physics has a long history
  and a bright future. In this report I highlight some of our joint
  analyses in the past, discuss the general solar physics context as
  I see it at present, and describe exciting research challenges which
  fit the Kyiv-Utrecht expertise and interests.

Title: Dynamics of the solar chromosphere. V. High-frequency
    modulation in ultraviolet image sequences from TRACE
Authors: de Wijn, A. G.; Rutten, R. J.; Tarbell, T. D.
Bibcode: 2005A&A...430.1119D
Altcode: 2007arXiv0706.1987D
  We search for signatures of high-frequency oscillations in the upper
  solar photosphere and low chromosphere in the context of acoustic
  heating of outer stellar atmospheres. We use ultraviolet image
  sequences of a quiet center-disk area from the Transition Region
  and Coronal Explorer (TRACE) mission which were taken with strict
  cadence regularity. The latter permits more reliable high-frequency
  diagnosis than in earlier work. Spatial Fourier power maps, spatially
  averaged coherence and phase-difference spectra, and spatio-temporal
  (k<SUB>h</SUB>,f) decompositions all contain high-frequency features
  that at first sight seem of considerable intrinsic interest but actually
  are more likely to represent artifacts of different nature. Spatially
  averaged phase difference measurement provides the most sensitive
  diagnostic and indicates the presence of acoustic modulation up to
  f≈20 mHz (periods down to 50 s) in internetwork areas.

Title: DOT++: the Dutch Open Telescope with 1.4-m aperture
Authors: Bettonvil, Felix C.; Hammerschlag, Robert H.; Sütterlin,
   Peter; Rutten, Robert J.; Jägers, Aswin P.; Snik, Frans
Bibcode: 2004SPIE.5489..362B
Altcode:
  The Dutch Open Telescope (DOT; http://dot.astro.uu.nl) on La Palma is
  a revolutionary open solar telescope, on an excellent site, on top
  of a transparent steel tower, and uses natural air flow to minimize
  local seeing. The aim is long-duration high-resolution imaging with
  a multi-wavelength camera system. In order to achieve this, the DOT
  is equipped with a diffraction limited imaging system and uses the
  speckle reconstruction technique for removing the remaining atmospheric
  turbulence. The DOT optical system is simple and consists currently of
  a 0.45m/F4.44 parabolic mirror and a 10x enlargement lens system. We
  present our plans to increase the aperture of the DOT from 0.45m to
  1.4m. The mirror support and telescope top shall be redesigned, but
  telescope, tower, multi-wavelength camera system and speckle system
  remain intact. The new optical design permits user selectable choice
  between angular resolution and field size, as well as transversal pupil
  shift introducing the possibility to use obstruction free apertures up
  to 65cm. The design will include a low order AO system, which improves
  the speckle S/N substantially during moderate seeing conditions.

Title: DOT tomography of the solar atmosphere. II. Reversed
    granulation in Ca II H
Authors: Rutten, R. J.; de Wijn, A. G.; Sütterlin, P.
Bibcode: 2004A&A...416..333R
Altcode:
  High-quality simultaneous image sequences from the Dutch Open Telescope
  (DOT) in the G band and the Ca II H line are used to quantify the
  occurrence of reversed granulation as a constituent of the subsonic
  brightness pattern observed as a background to acoustic oscillations
  in the quiet-Sun internetwork atmosphere. In the middle photosphere
  reversed granulation constitutes a much larger part of this background
  than at the larger heights sampled by ultraviolet radiation. The
  anticorrelation with the underlying granulation reaches about 50% at a
  temporal delay of 2-3 min, and increases with spatial image smoothing to
  mesogranular resolution. We discuss the nature of reversed granulation
  in terms of convection reversal, gravity waves, acoustic waves, and
  intergranular magnetism, suggest that the internetwork background
  pattern is primarily a mixture of the first two ingredients, and
  speculate that it is also an inverse canopy mapper.

Title: The Dutch Open Telescope on La Palma
Authors: Rutten, R. J.; Bettonvil, F. C. M.; Hammerschlag, R. H.;
   Jägers, A. P. L.; Leenaarts, J.; Snik, F.; Sütterlin, P.; Tziotziou,
   K.; de Wijn, A. G.
Bibcode: 2004IAUS..223..597R
Altcode: 2005IAUS..223..597R
  The Dutch Open Telescope (DOT) on La Palma is an innovative solar
  telescope combining open telescope structure and an open support tower
  with a multi-wavelength imaging assembly and with synchronous speckle
  cameras to generate high-resolution movies which sample different
  layers of the solar atmosphere simultaneously and co-spatially at high
  resolution over long durations. The DOT test and development phase is
  nearly concluded. The installation of an advanced speckle processor
  enables full science utilization including "Open-DOT" time allocation
  to the international community. Co-pointing with spectropolarimeters
  at other Canary Island telescopes and with TRACE furnishes valuable
  Solar-B precursor capabilities.

Title: DOT tomography of the solar atmosphere. I. Telescope summary
    and program definition
Authors: Rutten, R. J.; Hammerschlag, R. H.; Bettonvil, F. C. M.;
   Sütterlin, P.; de Wijn, A. G.
Bibcode: 2004A&A...413.1183R
Altcode:
  The Dutch Open Telescope (DOT) on La Palma is an innovative optical
  solar telescope capable of reaching 0.2 arcsec angular resolution
  over extended durations. The DOT presently progresses from technology
  testbed to a stable science configuration providing multi-wavelength
  imaging and multi-camera speckle data acquisition for tomographic
  mapping of the solar atmosphere. Large-volume speckle processing will
  soon enable frequent usage and community-wide time allocation, in
  particular for tandem operation with other solar telescopes pursuing
  spectropolarimetry and EUV imaging. We summarize the DOT hardware and
  software in the context of this increasing availability and outline
  the corresponding ``open-DOT'' program.

Title: Dynamics of the solar chromosphere IV. Evidence for atmospheric
    gravity waves from TRACE
Authors: Rutten, R. J.; Krijger, J. M.
Bibcode: 2003A&A...407..735R
Altcode:
  We study the low-frequency brightness modulation of internetwork
  regions in the low solar chromosphere using simultaneous ultraviolet
  and white-light image sequences from the Transition Region and Coronal
  Explorer (TRACE). The ultraviolet sequences exhibit a slowly varying
  brightness pattern in internetwork regions on which the more familiar
  acoustic three-minute oscillation is superimposed, with about half of
  the peak brightness reached in internetwork grains contributed by the
  low-frequency background. We address the nature of the latter, applying
  two-dimensional Fourier filtering to isolate it from the acoustic
  modulation. Spatio-temporal comparisons and selective time-delay scatter
  correlations between the ultraviolet and white-light low-frequency
  sequences establish that reversed granulation constitutes at most a
  minor part of the ultraviolet background. Fourier analysis shows that
  the meso-scale contribution dominates and consists of atmospheric
  gravity waves.

Title: The Dutch Open Telescope
Authors: Rutten, Robert J.
Bibcode: 2003ASSL..288..111R
Altcode: 2003ASSL..287..411R
  No abstract at ADS

Title: La Palma observations of umbral flashes
Authors: Rouppe van der Voort, L. H. M.; Rutten, R. J.; Sütterlin,
   P.; Sloover, P. J.; Krijger, J. M.
Bibcode: 2003A&A...403..277R
Altcode:
  We present high-quality Ca II H &amp; K data showing chromospheric
  flashes in sunspot umbrae collected with the Swedish Vacuum Solar
  Telescope, the Dutch Open Telescope, and the Swedish 1-m Solar Telescope
  at the Roque de los Muchachos Observatory on La Palma. Differential
  movies, time slices, spectrograms, and Fourier power maps demonstrate
  that umbral flashes and running penumbral waves are closely related
  oscillatory phenomena, combining upward shock propagation with coherent
  wave spreading over the entire spot. We attribute the flash brightening
  to large redshift by post-shock material higher up. We find no obvious
  relation between umbral dots and umbral flashes.

Title: Radiative Transfer in Stellar Atmospheres
Authors: Rutten, Robert J.
Bibcode: 2003rtsa.book.....R
Altcode:
  The main topic treated in these graduate course notes is the classical
  theory of radiative transfer for explaining stellar spectra. It
  needs relatively much attention to be mastered. Radiative transfer in
  gaseous media that are neither optically thin nor fully opaque and
  scatter to boot is a key part of astrophysics but not a transparent
  subject. These course notes represent a middle road between Mihalas'
  "Stellar Atmospheres" (graduate level and up) and the books by Novotny
  and Boehm-Vitense (undergraduate level). They are at about the level
  of Gray's "The observation and analysis of stellar photospheres" but
  emphasize NLTE radiative transfer rather than observational techniques
  and data interpretation.

Title: Multi-wavelength imaging system for the Dutch Open Telescope
Authors: Bettonvil, Felix C.; Suetterlin, Peter; Hammerschlag, Robert
   H.; Jagers, Aswin P.; Rutten, Robert J.
Bibcode: 2003SPIE.4853..306B
Altcode:
  The Dutch Open Telescope (DOT) is an innovative solar telescope,
  completely open, on an open steel tower, without a vacuum system. The
  aim is long-duration high resolution imaging and in order to achieve
  this the DOT is equipped with a diffraction limited imaging system
  in combination with a data acquisition system designed for use with
  the speckle masking reconstruction technique for removing atmospheric
  aberrations. Currently the DOT is being equipped with a multi-wavelength
  system forming a high-resolution tomographic imager of magnetic
  fine structure, topology and dynamics in the photosphere and low-
  and high chromosphere. Finally the system will contain 6 channels:
  G-band (430.5 nm), Ca II H (K) (396.8 nm), H-α (656.3 nm), Ba II
  (455.4 nm), and two continuum channels (432 and 651 nm). Two channels
  are in full operation now and observations show that the DOT produces
  real diffraction limited movies (with 0.2" resolution) over hours in
  G-band (430.5 nm) and continuum (432 nm).

Title: Utrecht Radiative Transfer Courses
Authors: Rutten, R. J.
Bibcode: 2003ASPC..288...99R
Altcode: 2003sam..conf...99R
  The Utrecht course ``The Generation and Transport of Radiation'' teaches
  basic radiative transfer to second-year students. It is a much-expanded
  version of the first chapter of Rybicki &amp; Lightman's ``Radiative
  Processes in Astrophysics''. After this course, students understand why
  intensity is measured per steradian, have an Eddington-Barbier feel for
  optically thick line formation, and know that scattering upsets LTE. The
  text is a computer-aided translation by Ruth Peterson of my 1992
  Dutch-language course. My aim is to rewrite this course in non-computer
  English and make it web-available at some time. In the meantime, copies
  of the Peterson translation are made yearly at Uppsala -- ask them,
  not me. Eventually it should become a textbook. <P />The Utrecht course
  ``Radiative Transfer in Stellar Atmospheres'' is a 30-hour course for
  third-year students. It treats NLTE line formation in plane-parallel
  stellar atmospheres at a level intermediate between the books by Novotny
  and Boehm-Vitense, and Mihalas' ``Stellar Atmospheres''. After this
  course, students appreciate that epsilon is small, that radiation
  can heat or cool, and that computers have changed the field. This
  course is web-available since 1995 and is regularly improved --
  but remains incomplete. Eventually it should become a textbook. <P
  />The three Utrecht exercise sets ``Stellar Spectra A: Basic Line
  Formation'', ``Stellar Spectra B: LTE Line Formation'', and ``Stellar
  Spectra C: NLTE Line Formation'' are IDL-based computer exercises for
  first-year, second-year, and third-year students, respectively. They
  treat spectral classification, Saha-Boltzmann population statistics,
  the curve of growth, the FAL-C solar atmosphere model, the role of
  H-minus in the solar continuum, LTE formation of Fraunhofer lines,
  inversion tactics, the Feautrier method, classical lambda iteration,
  and ALI computation. The first two sets are web-available since 1998;
  the third will follow. <P />Acknowledgement. Both courses owe much
  to previous Utrecht courses taught by the late Kees Zwaan. The third
  exercise set was developed by Phil Judge, Mandy Hagenaar, and Thijs
  Krijger. <P />Reverse acknowledgement. If you are a user of this free
  material you might refer to this summary and so boost my citation
  standing. Corrections are also welcome.

Title: NLTE in a Hot Hydrogen Star: Auer &amp; Mihalas Revisited
Authors: Wiersma, J.; Rutten, R. J.; Lanz, T.
Bibcode: 2003ASPC..288..130W
Altcode: 2003sam..conf..130W
  We pay tribute to two landmark papers published by Auer &amp; Mihalas
  in 1969. They modeled hot-star NLTE-RE hydrogen-only atmospheres,
  using two simplified hydrogen atoms: ApJ 156, 157: H I levels 1,
  2 and c, Lyman α the only line ApJ 156, 681: H I levels 1, 2, 3 and
  c, Balmer α the only line and computed LTE and NLTE models with the
  single line turned on and off. The results were extensively analyzed
  in the two papers. <P />Any student of stellar line formation should
  take these beautiful papers to heart. The final exercise in Rutten's
  lecture notes ``Radiative Transfer in Stellar Atmospheres'' asks the
  student to work through five pages of questions concerning diagrams from
  the first paper alone! That exercise led to the present work in which
  we recompute the Auer-Mihalas hot-hydrogen-star models with TLUSTY,
  adding results from a complete hydrogen atom for comparison. <P />Our
  motivation for this Auer-Mihalas re-visitation is twofold: <P />1. to
  add diagnostic diagrams to the ones published by Auer &amp; Mihalas,
  in particular B<SUB>ν</SUB>, J<SUB>ν</SUB>, S<SUB>ν</SUB> graphs to
  illustrate the role of the radiation field, and radiative heating &amp;
  cooling graphs to illustrate the radiative energy budget, <P />2. to
  see the effect of adding the rest of the hydrogen atom.

Title: Dynamical Behavior of the Upper Solar Photosphere
Authors: Rutten, R. J.
Bibcode: 2003IAUS..210..221R
Altcode:
  No abstract at ADS

Title: Solar Atmosphere Models
Authors: Rutten, R. J.
Bibcode: 2002JAD.....8....8R
Altcode:
  This contribution honoring Kees de Jager's 80th birthday is a review of
  "one-dimensional" solar atmosphere modeling that followed on the initial
  "Utrecht Reference Photosphere" of Heintze, Hubenet &amp; de Jager
  (1964). My starting point is the Bilderberg conference, convened by de
  Jager in 1967 at the time when NLTE radiative transfer theory became
  mature. The resulting Bilderberg model was quickly superseded by the
  HSRA and later by the VAL-FAL sequence of increasingly sophisticated
  NLTE continuum-fitting models from Harvard. They became the "standard
  models" of solar atmosphere physics, but Holweger's relatively simple
  LTE line-fitting model still persists as a favorite of solar abundance
  determiners. After a brief model inventory I discuss subsequent
  work on the major modeling issues (coherency, NLTE, dynamics)
  listed as to-do items by de Jager in 1968. The present conclusion
  is that one-dimensional modeling recovers Schwarzschild's (1906)
  finding that the lower solar atmosphere is grosso modo in radiative
  equilibrium. This is a boon for applications regarding the solar
  atmosphere as one-dimensional stellar example - but the real sun,
  including all the intricate phenomena that now constitute the mainstay
  of solar physics, is vastly more interesting.

Title: Dutch Open Telescope: status, results, prospects
Authors: Rutten, Robert J.; Sütterlin, Peter; de Wijn, Alfred G.;
   Hammerschlag, Robert H.; Bettonvil, Felix C. M.; Hoogendoorn, Piet W.;
   Jägers, Aswin P. L.
Bibcode: 2002ESASP.506..903R
Altcode: 2002svco.conf..903R; 2002ESPM...10..903R
  The Dutch Open Telescope (DOT) on La Palma is a revolutionary telescope
  achieving high-resolution imaging of the solar surface. The DOT combines
  a pioneering open design at an excellent wind-swept site with image
  restoration through speckle interferometry. Its open principle is now
  followed in major solar-telescope projects elsewhere. In the past three
  years the DOT became the first solar telescope to regularly obtain 0.2"
  resolution in extended image sequences, i.e., reaching the diffraction
  limit of its 45-cm primary mirror. Our aim for 2003-2005 is to turn
  the DOT into a 0.2" tomographic mapper of the solar atmosphere with
  frequent partnership in international multi-telescope campaigns through
  student-serviced time allocation. After 2005 we aim to triple the DOT
  resolution to 0.07" by increasing the aperture to 140 cm and to renew
  the speckle cameras and the speckle pipeline in order to increase
  the field size and sequence duration appreciably. These upgrades will
  maintain the DOT's niche as a tomographic high-resolution mapper in
  the era when GREGOR, Solar-B and SDO set the stage.

Title: Opening the Dutch Open Telescope
Authors: Rutten, R. J.; de Wijn, A. G.; Sütterlin, P.; Bettonvil,
   F. C. M.; Hammerschlag, R. H.
Bibcode: 2002ESASP.505..565R
Altcode: 2002IAUCo.188..565R; 2002solm.conf..565R
  We hope to "open the DOT" to the international solar physics
  community as a facility for high-resolution tomography of the solar
  atmosphere. Our aim is to do so combining peer-review time allocation
  with service-mode operation in a "hands-on-telescope" education
  program bringing students to La Palma to assist in the observing and
  processing. The largest step needed is considerable speedup of the
  DOT speckle processing.

Title: European Solar Magnetism Network
Authors: Rutten, Robert J.
Bibcode: 2002ESASP.505..569R
Altcode: 2002IAUCo.188..569R; 2002solm.conf..569R
  The future European Solar Magnetism Network (ESMN) will continue and
  expand collaborations of the past European Solar Magnetometry Network
  (ESMN). Both ESMN incarnations are funded by the European Commission,
  in the Fourth and Fifth Framework programmes respectively. The major
  past and future ESMN activity is the employment/deployment of European
  postdocs.

Title: Small-scale topology of solar atmospheric dynamics. V. Acoustic
    events and internetwork grains
Authors: Hoekzema, N. M.; Rimmele, T. R.; Rutten, R. J.
Bibcode: 2002A&A...390..681H
Altcode:
  We use high-quality observations from the Dunn Solar Telescope
  at NSO/Sacramento Peak to study spatio-temporal co-location of
  acoustic flux events in the photosphere and internetwork grains
  in the chromosphere. The events are diagnosed as sites with excess
  upward-propagating five-minute waves measured from Dopplergrams. The
  grains are repetitive bright internetwork features in simultaneous
  \CaII \KtwoV filtergrams. We find that the largest-flux sites in
  the granulation have appreciably larger than random probability to
  co-locate with exceptionally bright chromospheric internetwork grains,
  at an average delay of about two minutes which is likely to represent
  sound travel time to the chromosphere. This finding strengthens the
  case for acoustic grain excitation.

Title: The European Solar Magnetometry Network in 2000 - 2001
Authors: Rutten, R. J.
Bibcode: 2002joso.book....7R
Altcode:
  No abstract at ADS

Title: Dynamics of the solar chromosphere. III. Ultraviolet brightness
    oscillations from TRACE
Authors: Krijger, J. M.; Rutten, R. J.; Lites, B. W.; Straus, Th.;
   Shine, R. A.; Tarbell, T. D.
Bibcode: 2001A&A...379.1052K
Altcode:
  We analyze oscillations in the solar atmosphere using image sequences
  from the Transition Region and Coronal Explorer (TRACE) in three
  ultraviolet passbands which sample the upper solar photosphere and
  low chromosphere. We exploit the absence of atmospheric seeing in
  TRACE data to furnish comprehensive Fourier diagnostics (amplitude
  maps, phase-difference spectra, spatio-temporal decomposition) for
  quiet-Sun network and internetwork areas with excellent sampling
  statistics. Comparison displays from the ground-based Ca Ii H
  spectrometry that was numerically reproduced by Carlsson &amp;
  Stein are added to link our results to the acoustic shock dynamics
  in this simulation. The TRACE image sequences confirm the dichotomy
  in oscillatory behaviour between network and internetwork and show
  upward propagation above the cutoff frequency, the onset of acoustic
  shock formation in the upper photosphere, phase-difference contrast
  between pseudo-mode ridges and the interridge background, enhanced
  three-minute modulation aureoles around network patches, a persistent
  low-intensity background pattern largely made up of internal gravity
  waves, ubiquitous magnetic flashers, and low-lying magnetic canopies
  with much low-frequency modulation. The spatio-temporal occurrence
  pattern of internetwork grains is found to be dominated by acoustic
  and gravity wave interference. We find no sign of the high-frequency
  sound waves that have been proposed to heat the quiet chromosphere, but
  such measurement is hampered by non-simultaneous imaging in different
  passbands. We also find no signature of particular low-frequency
  fluxtube waves that have been proposed to heat the network. However,
  internal gravity waves may play a role in their excitation.

Title: Ba II 4554 Å speckle imaging as solar Doppler diagnostic
Authors: Sütterlin, P.; Rutten, R. J.; Skomorovsky, V. I.
Bibcode: 2001A&A...378..251S
Altcode:
  We present observations testing the Dopplergram capability of a
  narrow-band (80 mÅ) Lyot filter imaging the solar surface in the
  wings of the Ba II 4554 Å resonance line in combination with speckle
  reconstruction to obtain high angular resolution. The Ba II 4554 Å line
  is found to be an excellent tool for high-resolution Doppler mapping
  thanks to opacity insensitivity to temperature variations and line-width
  insensitivity to thermal broadening. The resulting Dopplergrams show
  concentrated downflows of 1.2-2.2 km;s<SUP>-1</SUP> in intergranular
  lanes that probably mark magnetic fluxtubes. Two-wavelength
  profile sampling is found to suffice for high-resolution Dopplergram
  construction. The filter will be installed as part of a multi-wavelength
  speckle imaging system on the new Dutch Open Telescope.

Title: DOT strategies versus Orbiter strategies
Authors: Rutten, Robert J.
Bibcode: 2001ESASP.493..357R
Altcode: 2001sefs.work..357R
  No abstract at ADS

Title: ESMN / European solar physics research area
Authors: Rutten, Robert J.
Bibcode: 2001ESASP.493..353R
Altcode: 2001sefs.work..353R
  No abstract at ADS

Title: Proxy Magnetometry with the Dutch Open Telescope
Authors: Rutten, R. J.; Hammerschlag, R. H.; Sütterlin, P.; Bettonvil,
   F. C. M.
Bibcode: 2001ASPC..236...25R
Altcode: 2001aspt.conf...25R
  No abstract at ADS

Title: A Multi-Channel Speckle Imaging System for the DOT
Authors: Sütterlin, P.; Hammerschlag, R. H.; Bettonvil, F. C. M.;
   Rutten, R. J.; Skomorovsky, V. I.; Domyshev, G. N.
Bibcode: 2001ASPC..236..431S
Altcode: 2001aspt.conf..431S
  No abstract at ADS

Title: Solar Atmospheric Dynamics (CD-ROM Directory: contribs/rutten)
Authors: Rutten, R. J.
Bibcode: 2001ASPC..223..117R
Altcode: 2001csss...11..117R
  No abstract at ADS

Title: The formation of G-band bright points I: Standard LTE modelling
Authors: Kiselman, D.; Rutten, R. J.; Plez, B.
Bibcode: 2001IAUS..203..287K
Altcode:
  Assuming LTE, we investigate the formation of the G band in models of
  quiet solar photosphere and a semiempirical flux-tube model (Briand
  &amp; Solanki 1995). Preliminary results agree with observations of
  of G-band bright-point contrast, though this a sensitive function
  of the amount of scattered light in the observations. Thus LTE line
  modelling in models constructed under the LTE assumptions seems to fit
  observations. This does not, however, necessarily imply that LTE is
  valid here. We also present LTE synthetic spectra of the same models
  for the full wavelength range from UV to IR. This serves to point out
  other promising pass bands for the observations of flux-tube structures.

Title: Proxy Magnetometry of the Photosphere: Why are G-Band Bright
    Points so Bright?
Authors: Rutten, R. J.; Kiselman, D.; Rouppe van der Voort, L.;
   Plez, B.
Bibcode: 2001ASPC..236..445R
Altcode: 2001aspt.conf..445R
  No abstract at ADS

Title: The formation of G-band bright points. I: Standard LTE
    modelling
Authors: Kiselman, D.; Rutten, R. J.; Plez, B.
Bibcode: 2000astro.ph.10390K
Altcode:
  Assuming LTE, we synthesise solar G band spectra from the semiempirical
  flux-tube model of Briand Solanki (1995). The results agree with
  observed G-band bright-point contrasts within the uncertainty set by the
  amount of scattered light. We find that it is the weakening of spectral
  lines within the flux tube that makes the bright-point contrast in the
  G band exceed the continuum contrast. We also synthesise flux-tube
  spectra assuming LTE for the full wavelength range from UV to IR,
  and identify other promising passbands for flux-tube observations.

Title: Dutch Open Telescope: Status and Prospects
Authors: Rutten, R. J.; Hammerschlag, R. H.; Bettonvil, F. M.;
   Suetterlin, P.
Bibcode: 2000SPD....3102107R
Altcode: 2000BAAS...32.1290R
  The Dutch Open Telescope (DOT) on La Palma in the Canary Islands is
  a small but revolutionary solar telescope of which the image quality
  matches the superb imaging of the Swedish Vacuum Solar Telescope (from
  whose building the DOT is operated). The DOT is an open parabolic 45cm
  reflector on an open 15m high tower, relying on mirror flushing by the
  trade winds that bring the best seeing at La Palma to avoid internal
  turbulence. A water-cooled field stop in the primary image reflects
  most sunlight and heat out of the telescope. The first data from the
  DOT combined with speckle reconstruction have yielded sunspot movies
  of outstanding quality. At present, a multi-channel imaging system is
  in construction for simultaneous registration of speckle sequences in
  the G band, in Ca II K and in Hα. The data pipeline permits continuous
  speckle data acquisition up to 0.5 Tb per day. The advantage of speckle
  reconstruction over adaptive optics is the much larger field of the
  restored scene, with the DOT camera's 100x130 arcsec at 0.2 arcsec
  resolution. The DOT science program is to study magnetic topology and
  dynamics throughout the photosphere and chromosphere.

Title: C. Fröhlich, M. C. E. Huber, S. K. Solanki and R. von Steiger
    (eds.), Solar Composition and its Evolution   from Core to Corona
Authors: Rutten, R. J.
Bibcode: 1999SSRv...90..526R
Altcode:
  No abstract at ADS

Title: (Inter-),Network Structure and DynamicS
Authors: Rutten, R. J.
Bibcode: 1999ASPC..184..181R
Altcode:
  The dynamical nature of the low solar atmosphere outside active regions
  is emphasized by recent observations and simulations alike. La Palma
  images, MDI maps, SUMER spectra, TRACE movies, hydrodynamic shock
  simulations and magnetohydrodynamic sheet simulations all impart
  non-quiet behavior to the "quiet Sun". This review begins with a brief
  summary of current insights and then focuses on various quiet-Sun
  questions that seem pertinent and solvable.

Title: C. Zwaan (1928 - 16 June 1999).
Authors: Rutten, R. J.; Schrijver, C. J.
Bibcode: 1999SoPh..188.....R
Altcode: 1999SoPh..188....0R
  No abstract at ADS

Title: Dynamics of the Solar Chromosphere. II. Ca II H<SUB>2V</SUB>
    and K<SUB>2V</SUB> Grains versus Internetwork Fields
Authors: Lites, B. W.; Rutten, R. J.; Berger, T. E.
Bibcode: 1999ApJ...517.1013L
Altcode:
  We use the Advanced Stokes Polarimeter at the NSO/Sacramento Peak
  Vacuum Tower Telescope to search for spatio-temporal correlations
  between enhanced magnetic fields in the quiet solar internetwork
  photosphere and the occurrence of Ca II H<SUB>2V</SUB> grains in the
  overlying chromosphere. We address the question of whether the shocks
  that produce the latter are caused by magnetism-related processes,
  or whether they are of purely hydrodynamic nature. The observations
  presented here are the first in which sensitive Stokes polarimetry is
  combined synchronously with high-resolution Ca II H spectrometry. We pay
  particular attention to the nature and significance of weak polarization
  signals from the internetwork domain, obtaining a robust estimate of
  our magnetographic noise level at an apparent flux density of only
  3 Mx cm<SUP>-2</SUP>. For the quiet Sun internetwork area analyzed
  here, we find no direct correlation between the presence of magnetic
  features with apparent flux density above this limit and the occurrence
  of H<SUB>2V</SUB> brightenings. This result contradicts the one-to-one
  correspondence claimed by Sivaraman &amp; Livingston. We also find no
  correspondence between H<SUB>2V</SUB> grains and the horizontal-field
  internetwork features discovered by Lites et al.

Title: F.-L. Deubner, J. Christensen-Dalsgaard, and D. Kurtz (eds.),
    New Eyes to See Inside the Sun and Stars, Proceedings of the 185th
    Symposium of the International Astronomical Union held in Kyoto,
    Japan, August 18 22, 1997
Authors: Rutten, R. J.
Bibcode: 1999SSRv...88..605R
Altcode:
  No abstract at ADS

Title: Magnetic Fields and Oscillations
Authors: Rutten, Robert J.
Bibcode: 1999PASP..111..380R
Altcode:
  No abstract at ADS

Title: The Dutch Open Telescope
Authors: Rutten, R. J.; Hammerschlag, R. H.; Bettonvil, F. C. M.
Bibcode: 1999ASPC..158...57R
Altcode: 1999ssa..conf...57R
  No abstract at ADS

Title: Internetwork Grains with TRACE
Authors: Rutten, R. J.; de Pontieu, B.; Lites, B.
Bibcode: 1999ASPC..183..383R
Altcode: 1999hrsp.conf..383R
  No abstract at ADS

Title: Dynamics of the Quiet Solar Chromosphere
Authors: Rutten, R. J.; Lites, B. W.; Berger, T. E.; Shine, R. A.
Bibcode: 1999ASPC..158..249R
Altcode: 1999ssa..conf..249R
  No abstract at ADS

Title: Obituary: Cornelis Zwaan, 1928-1999
Authors: Rutten, Rob; Schrijver, Karel
Bibcode: 1999BAAS...31.1612R
Altcode:
  No abstract at ADS

Title: Radiative Transfer for Grabs
Authors: Rutten, R. J.
Bibcode: 1999ASPC..158..306R
Altcode: 1999ssa..conf..306R
  No abstract at ADS

Title: Site tests for CLEAR by solar scintillometry
Authors: Beckers, Jacques M.; Rutten, Robert J.
Bibcode: 1998NewAR..42..489B
Altcode:
  We briefly describe the ongoing site survey for the NSO CLEAR project
  which aims to put a large-aperture solar telescope at a superior
  location. The initial results indicate that lake sites are far better
  than mountain sites, at least in the US.

Title: The Lower Solar Atmosphere Rapporteur Paper II
Authors: Rutten, Robert J.
Bibcode: 1998SSRv...85..269R
Altcode:
  This “rapporteur” report discusses the solar photosphere and low
  chromosphere in the context of chemical composition studies. The highly
  dynamical nature of the photosphere does not seem to jeopardize precise
  determination of solar abundances in classical fashion. It is still an
  open question how the highly dynamical nature of the low chromosphere
  contributes to first ionization potential (FIP) fractionation.

Title: Small-scale topology of solar atmosphere
    dynamics. III. Granular persistence and photospheric wave amplitudes
Authors: Hoekzema, N. M.; Brandt, P. N.; Rutten, R. J.
Bibcode: 1998A&A...333..322H
Altcode:
  We use a superb five-hour sequence of 900 solar images taken at La
  Palma to study long-duration persistence in the solar granulation,
  in the context of the long-lived ``intergranular holes'' discovered by
  \cite*{Roudier+others1997} %T AA: intergranular plumes + BP formation
  and the contention that these mark sites of convective downflow
  plumes. We develop a procedure to locate ``persistency regions'' that
  contain granular brightness maxima or minima over extended periods
  (up to 45 min), while allowing for lateral drifts due to horizontal
  flows. Statistical evaluation of the co-location probability for
  different pixel classes is first used to quantify the likelihood of
  long-term stationarity for different granular brightness classes and for
  the persistency regions, and then to evaluate the amount of preferential
  alignment, at different frequencies and time delays, between excessive
  Fourier modulation and granular brightness and persistence. The results
  support the existence of long-lived intergranular holes. There is large
  persistency difference between the brightest and the darkest features;
  some of the latter have location memories as long as two hours. In
  addition, the darkest intergranular features are found to be sites of
  enhanced Fourier modulation in the 3-min acoustic regime, improving
  earlier results through much higher statistical significance. However,
  the persistency regions containing intergranular holes do not seem
  to produce the excess acoustic emission that would be expected above
  downflow plumes.

Title: Small-scale topology of solar atmosphere dynamics. I. Wave
    sources and wave diffraction
Authors: Hoekzema, N. M.; Rutten, R. J.; Brandt, P. N.; Shine, R. A.
Bibcode: 1998A&A...329..276H
Altcode:
  We study the small-scale topology of dynamical phenomena in the
  quiet-sun internetwork atmosphere, using short-duration Fourier analysis
  of high-resolution filtergram sequences to obtain statistical estimates
  for the co-location probability of different fine-structure elements
  and wave modes. In this initial paper we concentrate on the topology
  of short-duration Fourier amplitude maps for the photosphere and the
  simultaneously observed overlying chromosphere. We find that these
  maps portray a complex mix of global modes and locally excited waves
  which necessitates a statistical approach. Various aspects including
  mesoscale patterning indicate the presence of subsurface wave sources
  and of subsurface wave diffraction by convective inhomogeneities.

Title: The Lower Solar Atmosphere
Authors: Rutten, R. J.
Bibcode: 1998sce..conf..269R
Altcode:
  No abstract at ADS

Title: Problem of iron abundance in the solar photosphere.
Authors: Kostyk, R. I.; Shchukina, N. G.; Rutten, R. J.
Bibcode: 1998BCrAO..94..118K
Altcode:
  The authors analyze the causes of the discrepancies.

Title: Small-scale topology of solar atmosphere
    dynamics. II. Granulation, K2v grains and waves
Authors: Hoekzema, N. M.; Rutten, R. J.
Bibcode: 1998A&A...329..725H
Altcode:
  We continue studying the small-scale topology of dynamical phenomena in
  the quiet-sun internetwork atmosphere through statistical estimation
  of the co-location probability of different fine-structure elements
  and wave modes. In this paper we chart spatial alignments between the
  granular brightness structuring of the photosphere, Ca ii K<SUB>2V</SUB>
  brightness patterns in the chromosphere, and wave amplitude patterns
  in both regimes as a function of time delay between the occurrences of
  the various features. These charts confirm the presence of excess 2--4
  min waves above dark intergranular lanes, the absence of excess 5 min
  waves above bright granules, the absence of expected alignments between
  photospheric and chromospheric wave patterning, and the broad-band
  nature of Ca ii K<SUB>2V</SUB> grain formation. In addition, they show
  significant alignments at large time delays that seem to be regulated
  by mesoscale patterning and pattern = migration.

Title: The Dutch Open Telescope
Authors: Rutten, R. J.; Hammerschlag, R. H.; Bettonvil, F. M.
Bibcode: 1997ASSL..225..289R
Altcode: 1997scor.proc..289R
  The Dutch Open Telescope is now being installed at La Palma. It
  is intended for optical solar observations with high spatial
  resolution. Its open design aims to minimize disturbances of the
  local air flow and so reduce the locally-generated component of
  the atmospheric seeing. This paper briefly describes the design,
  construction, short-term plans, and longer-term prospects.

Title: E. Kontizas, M. Kontizas, D.H. Morgan, and G.P. Vettolani
    (eds.). Wide-Faceted Field Spectroscopy, Proceedings of the 2nd
    Conference of the Working Group of IAU Commission 9 on "Wide-Field
    Imaging".
Authors: Rutten, R. J.
Bibcode: 1997SSRv...82..467R
Altcode:
  No abstract at ADS

Title: Modeling LiI and KI sensitivity to Pleiades activity.
Authors: Stuik, R.; Bruls, J. H. M. J.; Rutten, R. J.
Bibcode: 1997A&A...322..911S
Altcode:
  We compare schematic modeling of spots and plage on the surface of
  cool dwarfs with Pleiades data to assess effects of magnetic activity
  on the strengths of the LiI and KI resonance lines in Pleiades
  spectra. Comprehensive LiI and KI NLTE line formation computation is
  combined with comparatively well-established empirical solar spot and
  plage stratifications for solar-like stars. For other stars, we use
  theoretical constructs to model spots and plage that portray recipes
  commonly applied in stellar activity analyses. We find that - up to
  B-V=~1.1 - neither the LiI 670.8nm nor the KI 769.9nm line is sensitive
  to the presence of a chromosphere, in contrast to what is often
  supposed. Instead, both lines respond to the effects of activity on the
  stratification in the deep photosphere. They do so in similar fashion,
  making the KI line a valid proxy to study LiI line formation without
  spread from abundance variations. The computed effects of activity on
  line strength are opposite between plage and spots, differ noticeably
  between the empirical and theoretical solar-like stratifications, and
  considerably affect stellar broad-band colors. Our results indicate that
  one can neither easily establish, nor easily exclude, magnetic activity
  as major provider of KI line strength variation in the Pleiades. Since
  LiI line formation follows KI line formation closely, the same holds
  for LiI and the apparent lithium abundance.

Title: Ultraviolet Jets and Bright Points in the Solar
    Chromosphere. II. Statistical Correlations
Authors: Hoekzema, N. M.; Rutten, R. J.; Cook, J. W.
Bibcode: 1997ApJ...474..518H
Altcode:
  We use HRTS-VI rocket observations of the solar chromosphere to search
  for relationships between high-Dopplershift ``jets'' observed in the C
  I lines near λ = 156 nm and internetwork ``bright points'' observed
  in the λ = 160 nm continuum, in sequel to the analysis by Cook et
  al. which failed to find a direct connection between these phenomena. We
  now use the same data to establish statistical correlations between
  C I Dopplershift and 160 nm brightness modulation in internetwork
  areas. These mean relations emerge only after extensive spatial
  averaging and have small amplitude, but are definitely significant. They
  show that both C I Dopplershift and 160 nm brightness participate
  in oscillatory behavior with 3 minute periodicity and mesoscale (8
  Mm wavelength) as well as small-scale (1.4 Mm wavelength) spatial
  patterning. We find spatial and temporal phase relations between
  Dopplershift and brightness that confirm that jets and bright points
  should not be interpreted as isolated entities. Rather, they are
  chromospheric manifestations, with much pattern interference, of the
  oscillatory acoustic shock dynamics in the internetwork which also
  cause Ca II K<SUB>2V</SUB> grains. Additional small-scale modulation
  is present which we attribute to waves with f-mode character.

Title: First Results from SOHO on Waves Near the Solar Transition
    Region
Authors: Steffens, S.; Deubner, F. -L.; Fleck, B.; Wilhelm, K.;
   Schuhle, U.; Curdt, W.; Harrison, R.; Gurman, J.; Thompson, B. J.;
   Brekke, P.; Delaboudiniere, J. -P.; Lemaire, P.; Hessel, B.; Rutten,
   R. J.
Bibcode: 1997ASPC..118..284S
Altcode: 1997fasp.conf..284S
  We present first results from simultaneous observations with the
  CDS, EIT and SUMER instruments {please see Solar Physics 162 (1995)
  for a description of the instruments} onboard SOHO and the VTT at
  Tenerife. Our aim is to study the wave propagation, shock formation,
  and transmission properties of the upper chromosphere and transition
  region. The preliminary results presented here include the variation
  of velocity power spectra with height, difference in power between
  internetwork and network regions, and variations in mean flows displayed
  by different spectral lines.

Title: Chromospheric Dynamics and the FIP Flip
Authors: Rutten, R. J.
Bibcode: 1997ASPC..118..298R
Altcode: 1997fasp.conf..298R
  This paper consists of two parts. The first, resembling many other SOHO
  contributions in this volume, reports on a recent campaign in which
  SUMER was employed simultaneously with groundbased telescopes. The
  campaign is described but results are not yet in hand. The second
  part differs by proposing SUMER measurements and analysis to be
  contributed by you. It calls attention to the FIP effect, a puzzling
  outer-atmosphere element segregation that may have to do with quiet-sun
  chromospheric dynamics. SUMER data, including yours, may provide
  pertinent diagnostics.

Title: Dutch Open Telescope: Status and Prospects
Authors: Rutten, R. J.; Hammerschlag, R. H.; Bettonvil, F. C. M.
Bibcode: 1997ASPC..118..335R
Altcode: 1997fasp.conf..335R
  The Dutch Open Telescope represents a new solar telescope concept. Being
  open rather than evacuated, it leads the way to large-aperture high
  resolution telescopes. It is now being installed on La Palma.

Title: Ultraviolet Jets and Bright Points in the Solar
    Chromosphere. I. Search for One-to-One Relationships
Authors: Cook, J. W.; Rutten, R. J.; Hoekzema, N. M.
Bibcode: 1996ApJ...470..647C
Altcode:
  Ultraviolet spectrograms and spectroheliograms of the solar chromosphere
  are used to test the suggestion of Dere, Bartoe, &amp; Brueckner
  and Rutten &amp; Uitenbroek that bright points in quiet Sun cell
  interiors observed at = 1600 A, chromospheric jets observed in C I
  lines near λ = 1560 Å, and Ca II K<SUB>2v</SUB> bright points are
  associated with each other and that they are all manifestations of the
  same wave interaction in the nonmagnetic chromosphere. We search for
  spatio-temporal connections between 1600 Å bright points and C I blue
  jets using data from the High Resolution Telescope and Spectrograph
  VI rocket flight, comparing 1600 A spectrohellograms and a cospatial
  C I Doppler shift map on a pixel-by-pixel basis. We find no direct
  evidence for spatial colocation of bright points and jets, not for
  instantaneous correspondence and also not when allowing for phase
  delays as long as 3 minutes. Also, the average brightness evolution
  and its rms fluctuation are not obviously different between sites of
  large C I blueshift and the remaining surface.

Title: Book reviews
Authors: Humphreys, R. M.; Kemp, S.; Savonije, G.; van der Hucht,
   K. A.; van der Kruit, P. C.; Miley, G.; Bumba, V.; van Nieuwkoop,
   J.; van Hoolst, T.; Cox, A.; Rutten, R. J.; Kleczek, J.; de Jager,
   Cornelis; Jerzykiewicz, M.; Zwaan, C.; Poedts, S.; Sakai, Jun-Ichi;
   Pecker, J. -C.; Heikkila, W.; de Jong, T.; Wilson, P. R.; Müller,
   E. A.; Hoyng, P.; Icke, V.; Shore, S. N.; Achterberg, A.; Lucchin, F.;
   Butcher, H.; Ne'Eman, Y.; Heidmann, J.; Belton, M. J. S.; de Graauw,
   Th.; Waters, L. B. F. M.; Pacini, F.; Hultqvist, B.; Akasofu, S. -I.;
   Vial, J. -C.; Schatzman, E.; van der Laan, H.; Cole, K. D.; Vanbeveren,
   D.; Southwood, D.; van der Klis, M.; Katgert, Peter
Bibcode: 1996SSRv...76..339H
Altcode:
  No abstract at ADS

Title: The solar iron abundance: not the last word.
Authors: Kostik, R. I.; Shchukina, N. G.; Rutten, R. J.
Bibcode: 1996A&A...305..325K
Altcode:
  Determinations of the solar iron abundance have converged to the
  meteoritic value with the FeII studies of Holweger et al. (1990),
  Biemont et al. (1991) and Hannaford et al. (1992) and the FeI results
  of Holweger et al. (1991). However, the latter authors pointed out
  that Blackwell et al. (1984) obtained a discordant result from similar
  oscillator strengths. A recent debate on this lingering discrepancy
  by the Oxford and Kiel contenders themselves has not clarified
  the issue. We do so here by showing that it stems from systematic
  differences between equivalent widths and oscillator strengths which
  masquerade as difference in fitted damping enhancement factors. We first
  discuss the various error sources in classical abundance determination
  and then emulate both sides of the debate with abundance fits of our
  own. Our emulation of the Oxford side shows that the abundance anomaly
  claimed by Blackwell et al. (1984) for solar FeI 2.2eV lines vanishes
  when equivalent width measurements from other authors are combined
  with better evaluation of the collisional damping parameter. On the
  Kiel side, we find that the oscillator strengths of Bard et al. (1991)
  used by Holweger et al. (1991) produce a suspicious trend when used
  to fit solar FeI lines, whereas comparable application of oscillator
  strengths from Oxford does not. The trend is mainly set by categories
  of FeI lines not measured at Oxford; for lines of overlap the two sets
  agree and deliver the iron abundance value A_Fe_=7.62+/-0.04 which
  exceeds the meteorite value. The dissimilar lines may suffer from
  solar line-formation effects. We conclude that the issue of the solar
  iron abundance remains open. Definitive oscillator strengths are still
  needed, as well as verification of classical abundance determination
  by more realistic representations of the solar photosphere and of
  photospheric line formation.

Title: Chromospheric Oscillations
Authors: Rutten, R. J.
Bibcode: 1995ESASP.376a.151R
Altcode: 1995heli.conf..151R; 1995soho....1..151R
  Concentrates on the quiet-Sun chromosphere. Its internetwork areas
  are dynamically dominated by the so-called chromospheric three-minute
  oscillation. They are interpretationally dominated by the so-called Ca
  II K<SUB>2v</SUB> and H<SUB>2v</SUB> grains. The main points of this
  review are that the one phenomenon explains the other (both ways),
  that the quiet-Sun chromosphere is a clapotisphere pervaded by shocks
  above h ≍ 1 Mm, and that the existence of the classical temperature
  minimum is in doubt.

Title: The Determination of the Solar Iron Abundance from Fe I Lines
Authors: Kostik, R. I.; Shchukina, N. G.; Rutten, R. J.
Bibcode: 1995ASPC...78..399K
Altcode: 1995aapn.conf..399K
  No abstract at ADS

Title: Infrared lines as probes of solar magnetic features. VIII. MgI
    12μm diagnostics of sunspots.
Authors: Bruls, J. H. M. J.; Solanki, S. K.; Rutten, R. J.; Carlsson,
   M.
Bibcode: 1995A&A...293..225B
Altcode:
  Due to their large Zeeman sensitivity, the MgI lines at 12μm are
  important diagnostics of solar magnetism. The formation of their
  central emission features is now understood, enabling quantitative
  modeling and diagnostic application of these lines. We supply the
  first systematic analysis of solar MgI 12μm Stokes profiles employing
  detailed line-profile synthesis. We compute Stokes profiles of MgI
  12.32μm for the quiet Sun, for sunspot penumbrae and for the extended
  ("superpenumbral") magnetic canopies surrounding sunspots. We use these
  computations to analyze recent MgI 12μm observations by Hewagama
  et al. (1993). Our results are the following: (1) -Saha-Boltzmann
  temperature sensitivity explains that the emission peaks are stronger in
  penumbrae than in the quiet Sun, and that they disappear in umbrae. (2)
  -The formation heights of the emission features are approximately the
  same in penumbrae and in the quiet Sun, namely τ_500_=~10^-3^. (3)
  -The simple Seares formula allows relatively accurate determinations
  of field strength and magnetic inclination. (4) -The observed excess
  broadening of the σ-component peaks compared with the π component
  in penumbrae is well explained by primarily horizontal, smooth radial
  variation of the magnetic field strength. Additional small-scale
  variations are less than {DELTA}B =~200G. (5) -The vertical field
  gradients dB/dz in penumbrae range from 0.7G/km to 3G/km; the larger
  gradients occur near the umbra, the smaller ones near the outer edge of
  the penumbra. (6) -The MgI 12μm lines are well-suited to measure the
  base heights of superpenumbral magnetic canopies. These heights range
  between 300km and 500km above τ_500_=1 out to twice the sunspot radius,
  in excellent agreement with determinations from other infrared lines.

Title: Books-Received - Solar Surface Magnetism
Authors: Rutten, R. J.; Schrijver, C. J.
Bibcode: 1994Sci...265.1902R
Altcode:
  No abstract at ADS

Title: The non-LTE formation of Li I lines in cool stars
Authors: Carlsson, M.; Rutten, R. J.; Bruls, J. H. M. J.; Shchukina,
   N. G.
Bibcode: 1994A&A...288..860C
Altcode:
  We study the non-LTE (non local thermodynamic equilibrium)
  formation of Li I lines in the spectra of cool stars for a grid of
  radiative-equilibrium model atmospheres with variation in effective
  temperature, gravity, metallicity and lithium abundance. We analyze
  the mechanisms by which departures from LTE (local thermodynamic
  equilibrium) arise for Li I lines, first for the young sun (prior to
  its lithium depletion) and then across the cool-star grid. There are
  various mechanisms which compete in their effects on emergent Li I
  line strengths. Their neglect produces errors in lithium abundance
  determinations that vary in sign as well as size, both across the
  stellar grid and between different Li I lines (Figs). The errors are
  appreciable for all cooler stars and largest for cool lithium-rich
  metal-poor giants. They reverse sign between lithium-rich stars and
  lithium-poor stars for the λ=670.8nm resonance line, but not for the
  λ=610.4nm subordinate line. The non-LTE corrections are large enough
  that they should be taken into account in ongoing debates on lithium
  synthesis and depletion. We provide convenient numerical approximations
  of our results (Table 1) to this purpose. We end the paper with some
  examples in which non-LTE corrections change the slope of published
  relationships.

Title: The SIMURIS interferometric mission: Solar physics objectives
    and model payload
Authors: Dame, L.; Rutten, R. J.; Thorne, A. P.; Vial, J. C.
Bibcode: 1994AdSpR..14d.167D
Altcode: 1994AdSpR..14..167D
  We describe the SIMURIS Mission with emphasis on the scientific goals
  and related capabilities of the major instruments of the model payload.

Title: Book reviews
Authors: Burlaga, L. F.; Kleczek, J.; Schatzman, E.; Adams, D. J.;
   Rutten, R. J.; van der Kruit, P. C.; de Jager, Cornelis; Trams, N. R.;
   Righini, Alberto; Ergma, E.; Grün, Eberhard; Icke, Vincent
Bibcode: 1994SSRv...67..223B
Altcode:
  No abstract at ADS

Title: The Formation of Infrared Rydberg Lines
Authors: Rutten, R. J.; Carlsson, M.
Bibcode: 1994IAUS..154..309R
Altcode:
  No abstract at ADS

Title: Computation of Infrared Hydrogen Lines
Authors: Carlsson, M.; Rutten, R. J.
Bibcode: 1994IAUS..154..341C
Altcode:
  No abstract at ADS

Title: The Non-LTE Formation of Li I Lines from Cool Stars
Authors: Carlsson, M.; Rutten, R. J.; Bruls, J. H. M. J.; Shchukina,
   N. G.
Bibcode: 1994ASPC...64..270C
Altcode: 1994csss....8..270C
  No abstract at ADS

Title: Chromospheric oscillations
Authors: Lites, B. W.; Rutten, R. J.; Thomas, J. H.
Bibcode: 1994ASIC..433..159L
Altcode:
  No abstract at ADS

Title: On photospheric flows and chromospheric corks
Authors: Brandt, P. N.; Rutten, R. J.; Shine, R. A.; Trujillo Bueno, J.
Bibcode: 1994ASIC..433..251B
Altcode:
  No abstract at ADS

Title: Book Review: Sunspots: theory and observations / Kluwer, 1992
Authors: Rutten, R. J.
Bibcode: 1994SSRv...67..227R
Altcode: 1994SSRv...67..227T
  No abstract at ADS

Title: Solar Surface Magnetism
Authors: Rutten, Robert J.; Schrijver, Carolus J.
Bibcode: 1994ASIC..433.....R
Altcode: 1994ssm..work.....R
  No abstract at ADS

Title: MgI 12 μm diagnostics of sunspot penumbrae
Authors: Bruls, J. H. M. J.; Solanki, S. K.; Rutten, R. J.; Carlsson,
   M.
Bibcode: 1994smf..conf..191B
Altcode:
  No abstract at ADS

Title: Dynamics of the Solar Chromosphere. I. Long-Period Network
    Oscillations
Authors: Lites, B. W.; Rutten, R. J.; Kalkofen, W.
Bibcode: 1993ApJ...414..345L
Altcode:
  We analyze differences in solar oscillations between the chromospheric
  network and internetwork regions from a 1 hr sequence of spectrograms
  of a quiet region near disk center. The spectrograms contain Ca II
  H, Ca I 422.7 nm, and various Fe I blends in the Ca II H wing. They
  permit vertical tracing of oscillations throughout the photosphere
  and into the low chromosphere. We find that the rms amplitude of
  Ca II H line center Doppler fluctuations is about 1.5 km/s for both
  network and internetwork, but that the character of the oscillations
  differs markedly in these two regions. Within internetwork areas the
  chromospheric velocity power spectrum is dominated by oscillations
  with frequencies at and above the acoustic cutoff frequency. They are
  well correlated with the oscillations in the underlying photosphere,
  but they are much reduced in the network. In contrast, the network Ca
  II H line center velocity and intensity power spectra are dominated by
  low-frequency oscillations with periods of 5-20 min. Their signature
  is much clearer in our Ca II H line center measurements than in
  previously used diagnostics which are contaminated by signals from
  deeper layers. We find that these long-period oscillations are not
  correlated with underlying photospheric disturbances, and we discuss
  their nature.

Title: Book reviews
Authors: Murawski, K.; Grevesse, N.; Piteri, S.; Nieuwenhuyzen, H.;
   van der Hage, J. C. H.; Icke, Vincent; Hovenier, J. W.; Rutten, R. J.;
   De Greve, J. P.; Kaufmann, P.; Burki, G.; de Jager, Cornelis
Bibcode: 1993SSRv...65..365M
Altcode:
  No abstract at ADS

Title: Prospects for very-high-resolution solar physics with the
    Simuris interferometric mission.
Authors: Dame, L.; Martic, M.; Rutten, R. J.
Bibcode: 1993ESASP1157..119D
Altcode: 1993srfs.book..119D
  Simuris - the Solar, Solar System, and Stellar Interferometric Mission
  for Ultra-high Resolution Imaging and Spectroscopy - employs advanced
  interferometric techniques. Its payload includes two major instruments,
  which are the Solar Ultraviolet Network (SUN), an interferometric
  array of four 20 cm telescopes on a 2 m baseline, and the Imaging
  Fourier-Transform Spectrometer (IFTS), which uses light from a 40 cm
  Gregory telescope. Both instruments have active pointing capabilities of
  3 mas stability, and in addition SUN has an active co-phasing control
  to 1/50th of a wavelength. EUV multi-layer telescopes complete the
  payload for diagnostics of the very-high-temperature plasma.

Title: Book reviews
Authors: Rutten, R. J.; Mewe, R.; Houziaux, L.; Cheng, Chung-Chieh;
   van der Klis, M.; Sylwester, Janusz; Tajima, T.; Kresák, Ľ.; Minarik,
   S.; de Jager, Cornelis; van der Kruit, P. C.
Bibcode: 1993SSRv...65..181R
Altcode:
  No abstract at ADS

Title: Oscillations of the Magnetic Network
Authors: Lites, B. W.; Rutten, R. J.; Kalkofen, W.
Bibcode: 1993ASPC...46..530L
Altcode: 1993mvfs.conf..530L; 1993IAUCo.141..530L
  No abstract at ADS

Title: Stellar objectives of SIMURIS
Authors: Damé, L.; Coradini, M.; Foing, B.; Rutten, R. J.; Thorne,
   A.; Vial, J. C.
Bibcode: 1993MmSAI..64..345D
Altcode:
  No abstract at ADS

Title: Book Review: The observation and analysis of stellar
    photospheres / Cambridge U Press, 1992
Authors: Rutten, R. J.
Bibcode: 1993SSRv...65..183R
Altcode: 1993SSRv...65..183G
  No abstract at ADS

Title: SIMURIS: High-Resolution Solar Physics
Authors: Rutten, R. J.; Dame, L.
Bibcode: 1993ASPC...46..184R
Altcode: 1993mvfs.conf..184R; 1993IAUCo.141..184R
  No abstract at ADS

Title: Book-Review - the Sun - a Laboratory for Astrophysics
Authors: Schmelz, J. T.; Brown, J. C.; Rutten, R. J.
Bibcode: 1993SSRv...65..370S
Altcode:
  No abstract at ADS

Title: The SIMURIS interferometric mission: solar physics objectives
    and model payload (invited paper)
Authors: Damé, L.; Coradini, M.; Foing, B.; Rutten, R. J.; Thorne,
   A.; Vial, J. C.
Bibcode: 1993MmSAI..64..333D
Altcode:
  No abstract at ADS

Title: High resolution solar physics.
Authors: Rutten, Robert J.
Bibcode: 1992ESASP.354..163R
Altcode: 1992tsbi.rept..163R
  Solar physics is a prime example of the quest for high spatial
  resolution as the coming space frontier of astrophysics. The proximity
  of the Sun brings the enormous advantage that modest baselines suffice
  to fulfill an important goal: to resolve basic plasma processes at
  their characteristic scales. At such resolution, the solar atmosphere
  represents a plasma physics laboratory of broad interest. Concerted
  observations combining high spatial and temporal resolution with
  narrow-band diagnostics in the ultraviolet and the visible will deliver
  detailed insights is plasma processes that are ubiquitous in the cosmos,
  but resolvable only for the Sun. Space interferometry is the obvious
  way to fulfill this promise.

Title: The formation of helioseismology lines. I. NLTE effects in
    alkali spectra.
Authors: Bruls, J. H. M. J.; Rutten, R. J.; Shchukina, N. G.
Bibcode: 1992A&A...265..237B
Altcode:
  The authors study the NLTE formation of the solar K I and Na I resonance
  lines employed in helioseismology. They combine standard modeling of
  the solar atmosphere with comprehensive alkali model atoms, complete
  up to the Rydberg regime near the continuum, to study various NLTE
  mechanisms which interact to make the alkali population balances more
  complex than is the case for other minority species. In particular,
  they discuss a "photon suction" process which produces overpopulation
  of the neutral stage by driving a population flow from the reservoir in
  the singly ionized stage. They isolate this and other mechanisms with
  specifically tailored model atoms and provide a choice of simplified
  model atoms, trading precision against size, which are appropriate
  for future use in numerical simulations of the solar atmosphere.

Title: The formation of helioseismology lines. II. Modeling of alkali
    resonance lines with granulation.
Authors: Bruls, J. H. M. J.; Rutten, R. J.
Bibcode: 1992A&A...265..257B
Altcode:
  The authors model the NLTE formation of the solar Na I and
  K I resonance lines for an array of one-dimensional atmospheric
  models taken from a numerical simulation of the solar granulation by
  Nordlund and Stein. They discuss the nature of alkali-line sensitivity
  to granulation using hot and cool extremes from the simulation and
  study the granular modulation of diagnostics such as line bisectors and
  helioseismological resonance-cell response. They also show that granular
  structuring produces apparent spatially-averaged line broadening of
  similar magnitude as the ad hoc microturbulent and damping broadening
  invoked in traditional plane-parallel modeling.

Title: Model payload and system design of the SIMURIS interferometric
    mission
Authors: Dame, L.; Rutten, R. J.; Thorne, A. P.; Vial, J. C.
Bibcode: 1992wadc.iafcZ....D
Altcode:
  SIMURIS (Solar, Solar System, and Stellar Interferometric Mission
  for Ultrahigh Resolution Imaging and Spectroscopy) has been proposed
  to ESA as a Mission in the context of the Space Station in November
  1989 in answer to the Call for the Next Medium Size Mission (M2). It
  has completed, since, an Assessment Study, and is now proceeding for
  a Phase A. SIMURIS employs advanced interferometric techniques. The
  payload includes two major instruments which are the Solar Ultraviolet
  Network (SUN), an interferometric array of four 20-cm telescopes on
  a 2-m baseline, and the Imaging Fourier Transform Spectrometer (IFTS)
  which uses light from a 40-cm Gregory telescope. Both instruments have
  active pointing capabilities of 3 milliarcsec stability, and SUN has,
  in addition, an active cophasing control to 1/50th of a wavelength. EUV
  multilayer telescopes complete the payload for diagnostics of the very
  high temperature plasma. The SIMURIS model payload will be described
  with emphasis on the system design of the interferometric aspects of
  the instruments.

Title: Solar hydrogen lines in the infrared
Authors: Carlsson, M.; Rutten, R. J.
Bibcode: 1992A&A...259L..53C
Altcode:
  We study recently observed H I lines in the infrared solar spectrum,
  employing detailed NLTE modeling to explain their formation and to
  evaluate their diagnostic merits. The solar infrared H I lines vary much
  in character, depending on opacity and wavelength; our computations
  reproduce the observations closely. The line wings are primarily set
  by Stark broadening due to metal ions and protons; the line cores are
  sensitive to NLTE population departure divergence which is driven by
  Balmer-continuum photoionization. The formation heights of the H I
  lines range from the deep photosphere for near-infrared line wings
  to the chromosphere for line cores with wavelengths greater than 10
  microns; these features provide valuable diagnostics of the thermal
  structure of the solar atmosphere.

Title: Prospects with SIMURIS.
Authors: Dame, L.; Rutten, R. J.
Bibcode: 1992ESASP.344...21D
Altcode: 1992spai.rept...21D
  The authors give an introductory overview of the SIMURIS payload by
  briefly presenting its goals and concepts.

Title: Design Rationale of the Solar Ultraviolet Network / Sun
Authors: Dame, L.; Acton, L.; Bruner, M. E.; Connes, P.; Cornwell,
   T. J.; Curdt, W.; Foing, B. H.; Hammer, R.; Harrison, R.; Heyvaerts,
   J.; Karabin, M.; Marsch, E.; Martic, M.; Mattic, W.; Muller, R.;
   Patchett, B.; Roca-Cortes, T.; Rutten, R. J.; Schmidt, W.; Title,
   A. M.; Tondello, G.; Vial, J. C.; Visser, H.
Bibcode: 1992ESOC...39..995D
Altcode: 1992hrii.conf..995D
  No abstract at ADS

Title: The formation of the MG I emission features near 12 microns
Authors: Carlsson, M.; Rutten, R. J.; Shchukina, N. G.
Bibcode: 1992A&A...253..567C
Altcode:
  The formation of two Mg I 12-micron emission features in the
  solar spectrum, the existence of which was reported by Murcray et
  al. (1981), is explained using plane-parallel nonlocal thermodynamic
  equilibrium modeling with a radiative-equilibrium model atmosphere
  without chromosphere. It is shown that these emissions are a natural
  consequence of population depletion by line photon losses followed by
  population replenishment from the ionic reservoir in the highly excited
  levels. The results confirm the suggestion by Lemke and Holweger (1987)
  that the 12-micron lines are formed in the photosphere and disprove
  the claim by Zirin and Popp (1989) that the temperature minimum occurs
  much deeper than in standard models of the solar atmosphere.

Title: Formation of the MG 112 TTM Lines
Authors: Carlsson, M.; Rutten, R. J.; Shchukina, N. G.
Bibcode: 1992ASPC...26..518C
Altcode: 1992csss....7..518C
  No abstract at ADS

Title: Dynamics of the Quiet Solar Atmosphere: K2v Cell Grains Versus
    Magnetic Elements
Authors: Brandt, P. N.; Rutten, R. J.; Shine, R. A.; Trujillo Bueno, J.
Bibcode: 1992ASPC...26..161B
Altcode: 1992csss....7..161B
  No abstract at ADS

Title: Ca uc(ii) H<SUB>2v</SUB> and K<SUB>2v</SUB> cell grains
Authors: Rutten, Robert J.; Uitenbroek, Han
Bibcode: 1991SoPh..134...15R
Altcode:
  The bright Ca II H<SUB>2v</SUB> and K<SUB>2v</SUB> grains, which
  are intermittently present in the interiors of network cells in
  quiet-Sun areas, should provide important diagnostics of the dynamical
  interaction between the quiet photosphere and the chromosphere
  above it, but their nature has so far eluded identification. We
  review the extensive observational literature on these grains and on
  related phenomena. We resolve various contradictions, connect hitherto
  unconnected observations, distill new constraints and relate signatures
  in the measurement domain to signatures in the Fourier domain. We then
  review interpretations and simulation efforts, adding computations of
  our own to illustrate modeling options. We conclude that the grains are
  a hydrodynamical phenomenon in which magnetic fields do not play a major
  role. The grains are due to interference between a pervasive standing
  oscillation with about a 180 s periodicity and an 8 Mm horizontal
  wavelength in the chromosphere and the wave trains of the evanescent
  p-mode interference pattern in the upper photosphere. The roles of
  short-period waves, shock formation and granular piston excitation
  and the issue of long-lived patterning remain open; we suggest avenues
  for further research.

Title: Photospheric dynamics and the NLTE formation of the solar K
    I 769.9 NM line
Authors: Gomez, M. T.; Severino, G.; Rutten, R. J.
Bibcode: 1991A&A...244..501G
Altcode:
  Earlier analyses of the K I 769.9 nm resonance line are extended
  as a diagnostic of dynamical phenomena in the solar photosphere by
  evaluating the effects of dynamical variations on departures from LTE
  in the K I spectrum. Representative models for the solar granulation
  and the solar five-minute oscillation are used to estimate dynamical
  NLTE departures in the K I populations and to compare these to standarad
  plane-parallel NLTE modeling. Various NLTE mechanisms operate together
  in K I simultaneously with fortuitous cancellations; the resulting
  population departures vary less than 30 percent between dynamical
  perturbations. These results validate the assumption of departure
  invariance, i.e., adopting NLTE population departure coefficients from
  a standard static model for use in dynamical perturbations, as a good
  first-order approximation in K I 769.9 nm formation studies.

Title: Long-Period Oscillations of the Chromospheric Network
Authors: Lites, B. W.; Kalkofen, W.; Rutten, R. J.
Bibcode: 1991BAAS...23.1050L
Altcode:
  No abstract at ADS

Title: Book-Review - Solar and Stellar Granulation
Authors: Rutten, R. J.; Severino, G.; Rudiger, G.
Bibcode: 1991AN....312..147R
Altcode:
  No abstract at ADS

Title: K<SUB>2V</SUB> Cell Grains and Chromospheric Heating (With
    1 Figure)
Authors: Rutten, R. J.; Uitenbroek, H.
Bibcode: 1991mcch.conf...48R
Altcode:
  No abstract at ADS

Title: The solar photosphere: video movies and computer simulations.
Authors: Rutten, R. J.
Bibcode: 1990ComAp..14..297R
Altcode:
  No abstract at ADS

Title: Temperature Diagnostics of the Upper Photosphere
Authors: Shchukina, N. G.; Shcherbina, T. G.; Rutten, R. J.
Bibcode: 1990IAUS..138...29S
Altcode:
  No abstract at ADS

Title: Sun-As Line Formation
Authors: Rutten, Robert J.
Bibcode: 1990ASPC....9...91R
Altcode: 1990csss....6...91R
  Spectral line formation in the upper solar photosphere
  and temperature-minimum region is discussed to examine the
  effectiveness of spatially averaged '1D' modeling in solar and stellar
  applications. Problems associated with NLTE radiative transfer are
  described for the two-level atom, one bound level with a continuum,
  three bound levels, and for multiple levels. Successful applications
  of 1D modeling are reviewed where solar photospheric optical lines are
  used to calibrate stellar abundance determinations. The homogeneity
  or 1D LTE-RE formation of the sun is doubted, and the atmosphere
  is described as being highly dynamic. The LTE-RE assumption can be
  applied to the spatially averaged upper photosphere, but the problems
  associated with the NLTE effects must be considered to investigate
  the fine elements of solar structure.

Title: The Formation of the Mg I 12-Micron Emission Lines
Authors: Carlsson, M.; Rutten, R. J.; Shchukina, N. G.
Bibcode: 1990PDHO....7..260C
Altcode: 1990dysu.conf..260C; 1990ESPM....6..260C
  Contents: The Mg I 12 μm line, LTE or NLTE, chromospheric formation,
  photospheric formation, collisional NLTE; departure diffusion.

Title: Solar Oscillator Strengths as a Diagnostic Tool
Authors: Gurtovenko, E. A.; Kostik, R. I.; Rutten, R. J.
Bibcode: 1990IAUS..138...35G
Altcode:
  No abstract at ADS

Title: New solar oscillator strengths from Kiev
Authors: Gurtovenko, E. A.; Kostik, R. I.; Rutten, R. J.
Bibcode: 1990asos.conf...92G
Altcode:
  No abstract at ADS

Title: Summary Lecture
Authors: Rutten, R. J.
Bibcode: 1990IAUS..138..501R
Altcode:
  No abstract at ADS

Title: Book-Review - Solar and Stallar Granulation
Authors: Rutten, R. J.; Severino, G.
Bibcode: 1989Sci...246..137R
Altcode:
  No abstract at ADS

Title: Book-Review - Physics of Formation of Feii Lines Outside LTE
Authors: Viotti, R.; Vittone, A.; Friedjung, M.; Rutten, R. J.
Bibcode: 1989SSRv...50..617V
Altcode: 1989IAUCo.107..617V
  No abstract at ADS

Title: Book Review: Physics of formation of Fe II lines outside LTE
    (IAU Coll. 94) / Reidel, 1988
Authors: Viotti, R.; Vittone, A.; Friedjung, M.; Rutten, R. J.
Bibcode: 1989SSRv...50..618V
Altcode:
  No abstract at ADS

Title: Book-Review - Space - the Next Twenty-Five Years
Authors: Manno, V.; Kresák, Ľ.; de Jong, T.; Trimble, Virginia;
   Marov, Mikhail Ya.; Rutten, Robert J.; Vreeburg, J. P. B.; Kaufmann, P.
Bibcode: 1989SSRv...50..615M
Altcode: 1989IAUCo.107..615M
  No abstract at ADS

Title: Workshop Introduction
Authors: Rutten, R. J.
Bibcode: 1989ASIC..263....1R
Altcode: 1989ssg..conf....1R
  No abstract at ADS

Title: The Granulation Sensitivity of Neutral Metal Lines
Authors: Bruls, J. H. M. J.; Uitenbroek, H.; Rutten, R. J.
Bibcode: 1989ASIC..263..311B
Altcode: 1989ssg..conf..311B
  No abstract at ADS

Title: Solar and stellar granulation
Authors: Rutten, Robert J.; Severino, Giuseppe
Bibcode: 1989ASIC..263.....R
Altcode: 1989ssg..conf.....R
  No abstract at ADS

Title: Granulation and the NLTE Formation of K I 769. 9
Authors: Gomez, M. T.; Severino, G.; Rutten, R. J.
Bibcode: 1989ASIC..263..565G
Altcode: 1989ssg..conf..565G
  No abstract at ADS

Title: The Solar Photosphere: Video Movies and Computer Simulations
Authors: Rutten, Robert J.
Bibcode: 1989ComAp..14..297R
Altcode:
  No abstract at ADS

Title: The granulation sensitivity of helioseismology lines.
Authors: Rutten, R. J.; Bruls, J. H. M. J.; Gomez, M. T.; Severino, G.
Bibcode: 1988ESASP.286..251R
Altcode: 1988ssls.rept..251R
  The authors address the sensitivity of the Ni I 676.78 nm GONG line and
  the K I 769.9 nm resonance line to the temperature fluctuations present
  in the solar granulation. The temperature contrasts due to granulation
  are probably small in the upper photosphere where the cores of these
  two helioseismology lines are formed. However, the cores are sensitive
  also to the granulation temperature contrasts in the deep photosphere,
  through non-local NLTE effects in their formation. The largest effects
  are due to the ultraviolet radiation field, which is strongly modulated
  by the granulation in the deep layers where it escapes and carries these
  contrasts upwards to the line formation height. The authors discuss
  the resulting NLTE mechanisms and their influence on the two lines.

Title: The NLTE formation of iron lines in the solar photosphere
Authors: Rutten, Robert J.
Bibcode: 1988ASSL..138..185R
Altcode: 1988IAUCo..94..185R; 1988pffl.proc..185R
  The use of solar iron lines as diagnostics of the solar photosphere is
  discussed. NLTE in photospheric iron lines is discussed, including NLTE
  mechanisms, the description of NLTE, and published NLTE modeling of Fe
  I and Fe II. Iron NLTE and the mean atmosphere is addressed, including
  empirical plane-parallel modeling from lines and from continua and
  radiative-equilibrium modeling. The use of NLTE to study granulation,
  flux tubes, and flux bifurcations in the sun is considered.

Title: Oscillator Strengths from the High S/n Solar Spectrum
Authors: Rutten, R. J.
Bibcode: 1988IAUS..132..367R
Altcode:
  No abstract at ADS

Title: Feii Prospects in Solar Physics
Authors: Rutten, R. J.
Bibcode: 1988ASSL..138..317R
Altcode: 1988IAUCo..94..317R; 1988pffl.proc..317R
  No abstract at ADS

Title: Empirical gf-determination from the solar spectrum
Authors: Rutten, Robert J.; Kostik, Roman I.
Bibcode: 1988ASSL..138...83R
Altcode: 1988IAUCo..94...83R; 1988pffl.proc...83R
  The reliability of Fe I and Fe II oscillator strengths determined
  empirically from optical solar lines is tested. A comparison is made
  between gfW fits to the equivalent widths and gfD fits to the depths
  of 354 Fe I lines and 22 Fe II lines for various combinations of input
  parameters. The resulting scatter diagrams provide a measure of the
  attainable precision.

Title: Book reviews
Authors: Kleczek, J.; van Gent, R. H.; Rutten, Robert J.; de Munck,
   J. C.; Slottje, C.; Severne, G.; Pecker, Jean-Claude; Postma, H.;
   Grishchuk, L. P.; Niewenhuijzen, H.; Schuiling, R. D.; van Beek, H. F.;
   Reijnen, G. C. M.; Heidmann, Jean; Lemaire, J.; Bleeker, Johan; Icke,
   V.; Neéman, Y.; Feast, M. W.; de Graaff, W.
Bibcode: 1986SSRv...43..383K
Altcode:
  No abstract at ADS

Title: Book-Review - Progress in Stellar Spectral Line Formation
    Theory
Authors: Beckman, J. E.; Crivellari, L.; Rutten, R. J.
Bibcode: 1986SSRv...43Q.384B
Altcode:
  No abstract at ADS

Title: Book-Review - the A-Stars - Problems and Perspectives
Authors: Wolff, S. C.; Rutten, R. J.
Bibcode: 1985SSRv...41..396W
Altcode:
  No abstract at ADS

Title: Book-Review - Stellar Atmospheric Structural Patterns
Authors: Thoma, R. N.; Rutten, R. J.
Bibcode: 1985SSRv...41..394T
Altcode:
  No abstract at ADS

Title: Velocity Field in the Region of the Temperature Minimum of
    the Solar Atmosphere - Preliminary Results of a Determination of
    the Amplitude of the General Velocity Field
Authors: Gurtovenko, E. A.; Sheminova, V. A.; Rutten, R. J.
Bibcode: 1985SvA....29...72G
Altcode:
  No abstract at ADS

Title: Velocity field in the region of the temperature minimum of
    the solar atmosphere - Preliminary results of a determination of
    the amplitude of the general velocity field
Authors: Gurtovenko, E. A.; Sheminova, V. A.; Rutten, R. J.
Bibcode: 1985AZh....62..124G
Altcode:
  The weak Fraunhofer lines in the near wings of H, K Ca II lines have
  been analysed to study the velocity amplitude of the general velocity
  field in the middle and outer photospheric layers. The results
  confirm the basic well-known data on the velocity amplitude in the
  middle photospheric layers. Besides, it is shown that the radial and
  tangential components of the velocity amplitude continue to decrease
  with height also in the outer photosphere.

Title: Clean lines in the solar flux spectrum
Authors: Rutten, R. J.; van der Zalm, E. B. J.
Bibcode: 1984A&AS...55..171R
Altcode:
  Profile parameters of 602 unblended lines in the Sacramento Peak Atlas
  of the visual solar irradiance spectrum are profiled and compared
  to earlier measurements of the same lines in the Jungfraujoch Atlas
  of the solar disk-center intensity spectrum. The expected effects
  of solar rotation and of center-to-limb variations in the intensity
  profiles are discussed and compared to the actual trends. Finally,
  the spread is discussed.

Title: Revision of solar equivalent widths, Fe I oscillator strengths
    and the solar iron abundance.
Authors: Rutten, R. J.; van der Zalm, E. B. J.
Bibcode: 1984A&AS...55..143R
Altcode:
  The authors employ detailed modelling of solar Fe I and Fe II lines
  to calibrate the correction of equivalent widths for contamination
  by unresolved blends. They then determine the equivalent widths
  of 750 clean lines in the Jungfraujoch Atlas of the optical solar
  spectrum, and they compare these to the values given for the Utrecht
  Atlas by Moore et al. (1966). The authors also select clean Fe I
  lines, discuss their NLTE formation, construct a NLTE Fe I curve of
  growth, provide new oscillator strengths for weak Fe I lines, and
  revise the solar iron abundance to N<SUB>Fe</SUB>/N<SUB>H</SUB> =
  (4.3±0.5)10<SUP>-5</SUP>. The authors use the results to appraise
  the basis and methods of classical stellar abundance determination.

Title: Spectral Lines: Diagnostics
Authors: Rutten, R. J.
Bibcode: 1984ssdp.conf..379R
Altcode:
  The author discusses three aspects of employing spatially-averaged
  solar lines as diagnostics of small-scale photospheric structure: (1)
  partial redistribution vs. turbulence, (2) advertising the extreme limb,
  (3) quality of mean models.

Title: One Eye Closed - Two Eyes Closed
Authors: Rutten, R. J.
Bibcode: 1984ssdp.conf..446R
Altcode:
  No abstract at ADS

Title: Book-Review - Automated Data Retrieval in Astronomy
Authors: Jaschek, G.; Heintz, W.; Rutten, R. J.
Bibcode: 1983SSRv...36..417J
Altcode:
  No abstract at ADS

Title: Book reviews
Authors: Kleczek, J.; Nussbaumer, H.; van der Hucht, K. A.; De Greve,
   J. P.; Ooms, G.; Rutten, R. J.; van der Laan, H.; Jäger, F. W.;
   Reijnen, G. C. M.; Bijleveld, W.; Kistemaker, J.; de Jager, C.;
   Mustel, E. R.; Ne'Eman, Y.; Priest, E. R.; Stiller, H.; Seifert, W.;
   Namba, O.; Kuperus, M.; Hoekstra, Roel; Stumpers, F. L. H. M.; Frank,
   S.; Zimmerman, J. T. F.; De Loore, C.; Gendrin, R.; Schrijver, J.;
   Mulder, P. S.; Pounds, K. A.; Young, R. S.; Houziaux, L.; Engvold,
   O.; Bok, B. J.; de Graaff, W.
Bibcode: 1983SSRv...36..415K
Altcode:
  No abstract at ADS

Title: Empirical NLTE analyses of solar spectral lines. IV - The Fe
    I curve of growth
Authors: Rutten, R. J.; Zwaan, C.
Bibcode: 1983A&A...117...21R
Altcode:
  The effects of departures from local thermodynamic equilibrium on
  the equivalent widths of solar Fe I lines are studied as an example
  for the analysis of the stellar curve of growth. The solar curve of
  growth obtained is based on the nonlocal thermodynamic equilibrium
  (NLTE) modeling of the solar spectrum of Lites (1972, 1973) and the
  best available oscillator strengths for 991 Fe I lines. The empirical
  curve obtained relating the equivalent width-wavelength ratio to the
  oscillator strength under NLTE is shown to differ appreciably from
  curves neglecting the NLTE ionization departures, although these effects
  may be corrected by assuming a NLTE-masking model. Theoretical NLTE
  curves of growth are also presented, and splittings due to wavelength
  dependency, differences in NLTE excitation, and variation in collisional
  damping, which are largely hidden by noise in observed values, are
  discussed. A new value for the solar iron abundance of 0.000047 times
  the hydrogen abundance is also derived.

Title: NLTE masking and the Kiev Fe I oscillator strengths.
Authors: Rutten, R. J.
Bibcode: 1983HiA.....6..801R
Altcode:
  This paper describes the empirical solar-spectrum determinations of
  the oscillator strengths of 860 Fe I lines by Gurtovenko and Kostik
  (1981), and attempts to show their particular value for abundance
  analyses of cool stars.

Title: Empirical NLTE analyses of solar spectral lines. III - Iron
    lines versus LTE models of the photosphere
Authors: Rutten, R. J.; Kostik, R. I.
Bibcode: 1982A&A...115..104R
Altcode:
  We compare observational indications of departures from LTE in
  solar Fe I lines with published NLTE computations in the context of
  discrepancies between empirical LTE and NLTE models of the solar
  atmosphere. We find that the importance of departures from LTE in
  Fe I and similar spectra is often underestimated through neglect of
  opacity departures. We demonstrate with numerical experiments that the
  peculiarities of the LTE models are artifacts due to the neglect of NLTE
  departures; in particular, we so explain the Holweger-Müller LTE model
  quantitatively. However, we show also that the NLTE formation of most
  optical metal lines is fortuitously well-mimicked by LTE computation
  when using LTE models. Thus, LTE-derived metal abundances and empirical
  oscillator strengths happen to be fairly precise. The same may hold
  for the use of theoretical radiative- equilibrium models in stellar
  abundance determinations.

Title: Rhe sun as a star.
Authors: Rutten, R. J.; Cram, L. E.
Bibcode: 1981NASSP.450..473R
Altcode: 1981suas.nasa..473R
  The ways in which solar astrophysics serves to improve the methodology
  for the interpretation of stellar observations and the construction of
  stellar atmospheric models are summarized. The astrophysical processes
  highlighted are: stellar mass; stellar rotation; stellar magnetism;
  stellar composition; stellar companions; and evolutionary history.

Title: On the formation of Fe II lines in stellar spectra. I. Solar
    spatial intensity variation of lambda 3969.4.
Authors: Cram, L. E.; Rutten, R. J.; Lites, B. W.
Bibcode: 1980ApJ...241..374C
Altcode:
  High-spatial-resolution solar observations of the weak Fe II lambda
  3969.4 line are employed to study non-local thermodynamic equilibrium
  effects in Fe II line formation. This line is superposed on the wing
  of the Ca II H line, which raises its height of formation. The line
  shows extraordinary spatial intensity variations, including emission
  features whose contrast increases toward the limb. Observed profiles
  of the Fe II resonance lines in the UV are used to define formation
  parameters in a 15-level atomic model computation, which shows that Fe
  II subordinate lines are generally formed out of local thermodynamic
  equilibrium as a result of pumping by UV line-wing photons from the
  deep photosphere. For the lambda 3969.4 line, this pumping results in
  large sensitivity to the atmospheric structure in layers deeper than
  the layer of formation of the H-wing background intensity. The absence
  of intense emission cores in the Fe II resonance lines, the effects
  of partially coherent scattering, and the effects of chromospheric and
  photospheric inhomogeneities are discussed. It is found that emission
  of lambda 3969.4 provides a diagnostic of the inhomogeneous structure
  of the deep photosphere, for the sun and for late-type stars.

Title: Solar limb emission lines near CA II H &amp; K and their
    spatial intensity variations
Authors: Rutten, R. J.; Stencel, R. E.
Bibcode: 1980A&AS...39..415R
Altcode:
  The paper employs solar observations of high spatial and spectral
  resolution to identify emission lines seen in the extended wings of Ca
  II H &amp; K near the solar limb. Emission lines in the wings of H &amp;
  K represent valuable diagnostics of the atmospheres of cool stars,
  with a varying information content which depends on their particular
  formation mechanism. In solar spectrograms different emission line
  formation mechanisms can be distinguished by the character of the
  spatial intensity variation (SIV) apparent in the lines. Various classes
  of H &amp; K emission features, their spatial intensity variations and
  their formation mechanisms (of which some pose further problems) are
  discussed. A new extended list of line identifications is compiled based
  on their formation class and compared with other line lists. Evidence
  is found that stellar luminosity-sensitive lines tend to show large
  spatial intensity variation on the sun.

Title: Report from the discussion group on two dimensional
    spectroscopy
Authors: Righini, A.; Rutten, R. J.
Bibcode: 1980fsoo.conf..308R
Altcode:
  No abstract at ADS

Title: Afbuiging van straling door de zon. 1. De zonsverduistering
    van 1919.
Authors: Rutten, R. J.
Bibcode: 1980Zenit...7..276R
Altcode:
  No abstract at ADS

Title: Afbuiging van straling door de zon. 2. Nieuwe metingen.
Authors: Rutten, R. J.
Bibcode: 1980Zenit...7..372R
Altcode:
  No abstract at ADS

Title: An open LEST?
Authors: Hammerschlag, R. H.; Rutten, R. J.
Bibcode: 1980fsoo.conf..115H
Altcode:
  No abstract at ADS

Title: Solar observations with high spectral purity: needs and
    constraints (This paper was actually presented at the end of
    session 4.)
Authors: Rutten, R. J.
Bibcode: 1980fsoo.conf..221R
Altcode:
  No abstract at ADS

Title: Diagnostic Use of Feii H and K Wing Emission Lines
Authors: Cram, L. E.; Rutten, R. J.; Lites, B. W.
Bibcode: 1980LNP...114..102C
Altcode: 1980IAUCo..51..102C; 1980sttu.coll..102C
  No abstract at ADS

Title: Partial redistribution in the solar photospheric Ba II
    spectrum.
Authors: Rutten, R. J.; Milkey, R. W.
Bibcode: 1979ApJ...231..277R
Altcode:
  Recent studies of the effects of partial frequency redistribution
  (PRD) on the formation of strong chromospheric resonance lines are
  extended to weaker lines formed in the photosphere. Methods that have
  been derived to compute the PRD formation of the Ca II spectrum are
  applied to the solar Ba II spectrum. It is found that PRD is important
  in the formation of the 4554-A resonance line, and the results confirm
  that its effects on the line source function explain the emission
  wings of this line observed near the limb. Source function structure
  and line profiles for Ba II 4554 A and Ba II 5854 A are discussed;
  they may serve as an example for estimating effects of PRD in other
  photospheric lines in stellar atmospheres.

Title: An open LEST (Large European Solar Telescope)?
Authors: Hammerschlag, R. H.; Rutten, R. J.
Bibcode: 1979MmArc.106..115H
Altcode:
  No abstract at ADS

Title: Solar observations with high spectral purity: needs and
    constraints.
Authors: Rutten, R. J.
Bibcode: 1979MmArc.106..221R
Altcode:
  No abstract at ADS

Title: Report from the discussion on two-dimensional spectroscopy
    requirements for Lest (Large European Solar Telescope).
Authors: Righini, A.; Rutten, R. J.
Bibcode: 1979MmArc.106..308R
Altcode:
  No abstract at ADS

Title: Empirical NLTE analyses of solar spectral lines. II: The
    formation of the Ba II lambda 4554 resonance line.
Authors: Rutten, R. J.
Bibcode: 1978SoPh...56..237R
Altcode:
  The center-to-limb behaviour of the Ba II λ4554 resonance line is
  analyzed together with data from the extreme limb, flash intensities
  and profiles of other Ba II lines. An empirical NLTE method is employed
  in which the observed profiles are compared with synthesized profiles
  based on a standard one-dimensional model atmosphere, with the line
  source function, the barium abundance, the collisional damping and
  the atmospheric turbulence as free parameters.

Title: Report from the discussion group on two dimensional
    spectroscopy
Authors: Righini, A.; Rutten, R. J.
Bibcode: 1978fsoo.conf..308R
Altcode:
  No abstract at ADS

Title: Solar observations with high spectral purity: needs and
    constraints
Authors: Rutten, R. J.
Bibcode: 1978fsoo.conf..221R
Altcode:
  No abstract at ADS

Title: An open LEST?
Authors: Hammerschlag, R. H.; Rutten, R. J.
Bibcode: 1978fsoo.conf..115H
Altcode:
  No abstract at ADS

Title: Extreme limb observations of Ba II λ 4554 and Mg  i λ 4571
Authors: Rutten, R. J.
Bibcode: 1977SoPh...51....3R
Altcode:
  Profiles of the Ba II λ 4554 resonance line and the Mg I λ 4571
  intercombination line are presented, observed near the limb of the
  Sun. They are obtained from eclipse spectrograms with good spectroscopic
  resolution and an accurate height calibration. The reduction of the
  observations is described and detailed profiles are given for a range
  of viewing angles (1/cos θ = 4 - 22).

Title: Report of the Dutch expedition to the 1970 March 7 solar
    eclipse.
Authors: Houtgast, J.; Namba, C.; Rutten, R. J.
Bibcode: 1976PKNAW..79..221H
Altcode:
  No abstract at ADS

Title: Report of the Dutch expedition to the 1970 March 7 solar
    eclipse. Ch. 1.
Authors: Houtgast, J.; Namba, O.; Rutten, R. J.
Bibcode: 1976seob.conf....3H
Altcode:
  No abstract at ADS

Title: Solar Eclipse Observations and Ba II line formation
Authors: Rutten, Robert Jelle Rob
Bibcode: 1976PhDT.......177R
Altcode:
  No abstract at ADS

Title: Report of the Dutch expedition to the 1970 March 7 solar
    eclipse.
Authors: Houtgast, J.; Namba, O.; Rutten, R. J.
Bibcode: 1976PRNAA..79..221H
Altcode: 1976RNAAS..79..221H
  No abstract at ADS

