Author name code: vial
ADS astronomy entries on 2022-09-14
author:"Vial, Jean-Claude" 
------------------------------------------------------------------------  

Title: Linking Small-scale Solar Wind Properties with Large-scale
    Coronal Source Regions through Joint Parker Solar Probe-Metis/Solar
    Orbiter Observations
Authors: Telloni, Daniele; Zank, Gary P.; Sorriso-Valvo, Luca;
   D'Amicis, Raffaella; Panasenco, Olga; Susino, Roberto; Bruno, Roberto;
   Perrone, Denise; Adhikari, Laxman; Liang, Haoming; Nakanotani, Masaru;
   Zhao, Lingling; Hadid, Lina Z.; Sánchez-Cano, Beatriz; Verscharen,
   Daniel; Velli, Marco; Grimani, Catia; Marino, Raffaele; Carbone,
   Francesco; Mancuso, Salvatore; Biondo, Ruggero; Pagano, Paolo; Reale,
   Fabio; Bale, Stuart D.; Kasper, Justin C.; Case, Anthony W.; de Wit,
   Thierry Dudok; Goetz, Keith; Harvey, Peter R.; Korreck, Kelly E.;
   Larson, Davin; Livi, Roberto; MacDowall, Robert J.; Malaspina, David
   M.; Pulupa, Marc; Stevens, Michael L.; Whittlesey, Phyllis; Romoli,
   Marco; Andretta, Vincenzo; Deppo, Vania Da; Fineschi, Silvano; Heinzel,
   Petr; Moses, John D.; Naletto, Giampiero; Nicolini, Gianalfredo;
   Spadaro, Daniele; Stangalini, Marco; Teriaca, Luca; Capobianco,
   Gerardo; Capuano, Giuseppe E.; Casini, Chiara; Casti, Marta; Chioetto,
   Paolo; Corso, Alain J.; Leo, Yara De; Fabi, Michele; Frassati,
   Federica; Frassetto, Fabio; Giordano, Silvio; Guglielmino, Salvo L.;
   Jerse, Giovanna; Landini, Federico; Liberatore, Alessandro; Magli,
   Enrico; Massone, Giuseppe; Messerotti, Mauro; Pancrazzi, Maurizio;
   Pelizzo, Maria G.; Romano, Paolo; Sasso, Clementina; Schühle, Udo;
   Slemer, Alessandra; Straus, Thomas; Uslenghi, Michela; Volpicelli,
   Cosimo A.; Zangrilli, Luca; Zuppella, Paola; Abbo, Lucia; Auchère,
   Frédéric; Cuadrado, Regina Aznar; Berlicki, Arkadiusz; Ciaravella,
   Angela; Lamy, Philippe; Lanzafame, Alessandro; Malvezzi, Marco;
   Nicolosi, Piergiorgio; Nisticò, Giuseppe; Peter, Hardi; Solanki,
   Sami K.; Strachan, Leonard; Tsinganos, Kanaris; Ventura, Rita; Vial,
   Jean-Claude; Woch, Joachim; Zimbardo, Gaetano
Bibcode: 2022ApJ...935..112T
Altcode:
  The solar wind measured in situ by Parker Solar Probe in the very
  inner heliosphere is studied in combination with the remote-sensing
  observation of the coronal source region provided by the METIS
  coronagraph aboard Solar Orbiter. The coronal outflows observed near
  the ecliptic by Metis on 2021 January 17 at 16:30 UT, between 3.5 and
  6.3 R <SUB>⊙</SUB> above the eastern solar limb, can be associated
  with the streams sampled by PSP at 0.11 and 0.26 au from the Sun,
  in two time intervals almost 5 days apart. The two plasma flows
  come from two distinct source regions, characterized by different
  magnetic field polarity and intensity at the coronal base. It follows
  that both the global and local properties of the two streams are
  different. Specifically, the solar wind emanating from the stronger
  magnetic field region has a lower bulk flux density, as expected,
  and is in a state of well-developed Alfvénic turbulence, with low
  intermittency. This is interpreted in terms of slab turbulence in the
  context of nearly incompressible magnetohydrodynamics. Conversely,
  the highly intermittent and poorly developed turbulent behavior of the
  solar wind from the weaker magnetic field region is presumably due to
  large magnetic deflections most likely attributed to the presence of
  switchbacks of interchange reconnection origin.

Title: Empirical relations between the intensities of Lyman lines
    of H and He<SUP>+</SUP>
Authors: Gordino, M.; Auchère, F.; Vial, J. -C.; Bocchialini, K.;
   Hassler, D. M.; Bando, T.; Ishikawa, R.; Kano, R.; Kobayashi, K.;
   Narukage, N.; Trujillo Bueno, J.; Winebarger, A.
Bibcode: 2022A&A...657A..86G
Altcode: 2022arXiv220101519G
  Context. Empirical relations between major UV and extreme UV spectral
  lines are one of the inputs for models of chromospheric and coronal
  spectral radiances and irradiances. They are also needed for the
  interpretation of some of the observations of the Solar Orbiter
  mission. <BR /> Aims: We aim to determine an empirical relation between
  the intensities of the H I 121.6 nm and He II 30.4 nm Ly-α lines. <BR
  /> Methods: Images at 121.6 nm from the Chromospheric Lyman-Alpha
  Spectro Polarimeter (CLASP) and Multiple XUV Imager (MXUVI) sounding
  rockets were co-registered with simultaneous images at 30.4 nm from the
  EIT and AIA orbital telescopes in order to derive a spatially resolved
  relationship between the intensities. <BR /> Results: We have obtained
  a relationship between the H I 121.6 nm and He II 30.4 nm intensities
  that is valid for a wide range of solar features, intensities, and
  activity levels. Additional SUMER data have allowed the derivation of
  another relation between the H I 102.5 nm (Ly-β) and He II 30.4 nm
  lines for quiet-Sun regions. We combined these two relationships to
  obtain a Ly-α/Ly-β intensity ratio that is comparable to the few
  previously published results. <BR /> Conclusions: The relationship
  between the H I 121.6 nm and He II 30.4 nm lines is consistent with the
  one previously obtained using irradiance data. We have also observed
  that this relation is stable in time but that its accuracy depends on
  the spatial resolution of the observations. The derived Ly-α/Ly-β
  intensity ratio is also compatible with previous results.

Title: The first coronal mass ejection observed in both visible-light
    and UV H I Ly-α channels of the Metis coronagraph on board Solar
    Orbiter
Authors: Andretta, V.; Bemporad, A.; De Leo, Y.; Jerse, G.; Landini,
   F.; Mierla, M.; Naletto, G.; Romoli, M.; Sasso, C.; Slemer, A.;
   Spadaro, D.; Susino, R.; Talpeanu, D. -C.; Telloni, D.; Teriaca, L.;
   Uslenghi, M.; Antonucci, E.; Auchère, F.; Berghmans, D.; Berlicki,
   A.; Capobianco, G.; Capuano, G. E.; Casini, C.; Casti, M.; Chioetto,
   P.; Da Deppo, V.; Fabi, M.; Fineschi, S.; Frassati, F.; Frassetto,
   F.; Giordano, S.; Grimani, C.; Heinzel, P.; Liberatore, A.; Magli, E.;
   Massone, G.; Messerotti, M.; Moses, D.; Nicolini, G.; Pancrazzi, M.;
   Pelizzo, M. -G.; Romano, P.; Schühle, U.; Stangalini, M.; Straus,
   Th.; Volpicelli, C. A.; Zangrilli, L.; Zuppella, P.; Abbo, L.; Aznar
   Cuadrado, R.; Bruno, R.; Ciaravella, A.; D'Amicis, R.; Lamy, P.;
   Lanzafame, A.; Malvezzi, A. M.; Nicolosi, P.; Nisticò, G.; Peter,
   H.; Plainaki, C.; Poletto, L.; Reale, F.; Solanki, S. K.; Strachan,
   L.; Tondello, G.; Tsinganos, K.; Velli, M.; Ventura, R.; Vial, J. -C.;
   Woch, J.; Zimbardo, G.
Bibcode: 2021A&A...656L..14A
Altcode:
  Context. The Metis coronagraph on board Solar Orbiter offers a new
  view of coronal mass ejections (CMEs), observing them for the first
  time with simultaneous images acquired with a broad-band filter in
  the visible-light interval and with a narrow-band filter around the
  H I Ly-α line at 121.567 nm, the so-called Metis UV channel. <BR />
  Aims: We show the first Metis observations of a CME, obtained on 16
  and 17 January 2021. The event was also observed by the EUI/FSI imager
  on board Solar Orbiter, as well as by other space-based coronagraphs,
  such as STEREO-A/COR2 and SOHO/LASCO/C2, whose images are combined here
  with Metis data. <BR /> Methods: Different images are analysed here
  to reconstruct the 3D orientation of the expanding CME flux rope using
  the graduated cylindrical shell model. This also allows us to identify
  the possible location of the source region. Measurements of the CME
  kinematics allow us to quantify the expected Doppler dimming in the
  Ly-α channel. <BR /> Results: Observations show that most CME features
  seen in the visible-light images are also seen in the Ly-α images,
  although some features in the latter channel appear more structured
  than their visible-light counterparts. We estimated the expansion
  velocity of this event to be below 140 km s<SUP>−1</SUP>. Hence,
  these observations can be understood by assuming that Doppler dimming
  effects do not strongly reduce the Ly-α emission from the CME. These
  velocities are comparable with or smaller than the radial velocities
  inferred from the same data in a similar coronal structure on the
  east side of the Sun. <BR /> Conclusions: The first observations by
  Metis of a CME demonstrate the capability of the instrument to provide
  valuable and novel information on the structure and dynamics of these
  coronal events. Considering also its diagnostics capabilities regarding
  the conditions of the ambient corona, Metis promises to significantly
  advance our knowledge of such phenomena. <P />Movies are available at <A
  href="https://www.aanda.org/10.1051/0004-6361/202142407/olm">https://www.aanda.org</A>

Title: First light observations of the solar wind in the outer corona
    with the Metis coronagraph
Authors: Romoli, M.; Antonucci, E.; Andretta, V.; Capuano, G. E.; Da
   Deppo, V.; De Leo, Y.; Downs, C.; Fineschi, S.; Heinzel, P.; Landini,
   F.; Liberatore, A.; Naletto, G.; Nicolini, G.; Pancrazzi, M.; Sasso,
   C.; Spadaro, D.; Susino, R.; Telloni, D.; Teriaca, L.; Uslenghi,
   M.; Wang, Y. -M.; Bemporad, A.; Capobianco, G.; Casti, M.; Fabi, M.;
   Frassati, F.; Frassetto, F.; Giordano, S.; Grimani, C.; Jerse, G.;
   Magli, E.; Massone, G.; Messerotti, M.; Moses, D.; Pelizzo, M. -G.;
   Romano, P.; Schühle, U.; Slemer, A.; Stangalini, M.; Straus, T.;
   Volpicelli, C. A.; Zangrilli, L.; Zuppella, P.; Abbo, L.; Auchère,
   F.; Aznar Cuadrado, R.; Berlicki, A.; Bruno, R.; Ciaravella, A.;
   D'Amicis, R.; Lamy, P.; Lanzafame, A.; Malvezzi, A. M.; Nicolosi,
   P.; Nisticò, G.; Peter, H.; Plainaki, C.; Poletto, L.; Reale, F.;
   Solanki, S. K.; Strachan, L.; Tondello, G.; Tsinganos, K.; Velli,
   M.; Ventura, R.; Vial, J. -C.; Woch, J.; Zimbardo, G.
Bibcode: 2021A&A...656A..32R
Altcode: 2021arXiv210613344R
  In this work, we present an investigation of the wind in the solar
  corona that has been initiated by observations of the resonantly
  scattered ultraviolet emission of the coronal plasma obtained with
  UVCS-SOHO, designed to measure the wind outflow speed by applying
  Doppler dimming diagnostics. Metis on Solar Orbiter complements the
  UVCS spectroscopic observations that were performed during solar
  activity cycle 23 by simultaneously imaging the polarized visible
  light and the H I Lyman-α corona in order to obtain high spatial and
  temporal resolution maps of the outward velocity of the continuously
  expanding solar atmosphere. The Metis observations, taken on May 15,
  2020, provide the first H I Lyman-α images of the extended corona
  and the first instantaneous map of the speed of the coronal plasma
  outflows during the minimum of solar activity and allow us to identify
  the layer where the slow wind flow is observed. The polarized visible
  light (580-640 nm) and the ultraviolet H I Lyα (121.6 nm) coronal
  emissions, obtained with the two Metis channels, were combined in
  order to measure the dimming of the UV emission relative to a static
  corona. This effect is caused by the outward motion of the coronal
  plasma along the direction of incidence of the chromospheric photons
  on the coronal neutral hydrogen. The plasma outflow velocity was then
  derived as a function of the measured Doppler dimming. The static
  corona UV emission was simulated on the basis of the plasma electron
  density inferred from the polarized visible light. This study leads
  to the identification, in the velocity maps of the solar corona, of
  the high-density layer about ±10° wide, centered on the extension
  of a quiet equatorial streamer present at the east limb - the coronal
  origin of the heliospheric current sheet - where the slowest wind
  flows at about 160 ± 18 km s<SUP>−1</SUP> from 4 R<SUB>⊙</SUB>
  to 6 R<SUB>⊙</SUB>. Beyond the boundaries of the high-density layer,
  the wind velocity rapidly increases, marking the transition between
  slow and fast wind in the corona.

Title: High-resolution observations of prominence plume formation
    with the new vacuum solar telescope
Authors: Xue, Jian-Chao; Vial, Jean-Claude; Su, Yang; Li, Hui; Xu,
   Zhi; Su, Ying-Na; Zhou, Tuan-Hui; Li, Zhen-Tong
Bibcode: 2021RAA....21..222X
Altcode:
  Prominence plumes are evacuated upflows that emerge from bubbles
  below prominences, whose formation mechanism is still unclear. Here
  we present a detailed study of plumes in a quiescent prominence using
  the high-resolution Hα filtergrams at the line center as well as line
  wing at ± 0.4 Å from the New Vacuum Solar Telescope. Enhancements of
  brightening, blue shifts, and turbulence at the fronts of plumes are
  found during their formation. Some large plumes split at their heads and
  finger-shaped structures are formed between them. Blue-shifted flows
  along the bubble-prominence interface are found before and during the
  plume formation. Our observations are consistent with the hypothesis
  that prominence plumes are related to coupled Kelvin-Helmholtz and
  Rayleigh-Taylor (KH/RT) instabilities. Plume splittings and fingers are
  evidence of RT instability, and the flows may increase the growth rate
  of KH/RT instabilities. However, the significant turbulence at plume
  fronts may suggest that the RT instability is triggered by the plumes
  penetrating into the prominence. In this scenario, extra mechanisms
  are necessary to drive the plumes.

Title: White-light Continuum Observation of the Off-limb Loops of
the SOL2017-09-10 X8.2 Flare: Temporal and Spatial Variations
Authors: Zhao, Junwei; Liu, Wei; Vial, Jean-Claude
Bibcode: 2021ApJ...921L..26Z
Altcode: 2021arXiv211014130Z
  Observations of the Sun's off-limb white-light (WL) flares offer rare
  opportunities to study the energy release and transport mechanisms
  in flare loops. One of the best such events was SOL2017-09-10, an
  X8.2 flare that occurred near the Sun's west limb on 2017 September
  10 and produced a WL loop system lasting more than 60 minutes and
  reaching an altitude higher than 30 Mm. The event was well observed
  by a suite of ground- and space-based instruments, including the
  Solar Dynamics Observatory/Helioseismic and Magnetic Imager (SDO/HMI)
  that captured its off-limb loops in WL continuum near Fe I 6173 Å,
  and the Atmospheric Imager Assembly (SDO/AIA) that observed its
  ultraviolet (UV) and extreme-ultraviolet (EUV) counterparts. We
  found quasi-periodic pulsations in the WL and UV emissions at the
  flare loop-top with a period around 8.0 minutes. Each pulsation
  appears to have an EUV counterpart that occurs earlier in time and
  higher in altitude. Despite many similarities in the WL and UV images
  and light curves, the WL flux at the loop-top continues to grow for
  about 16 minutes while the UV fluxes gradually decay. We discuss the
  implication of these unprecedented observations on the understanding
  of the enigmatic off-limb WL flare emission mechanisms.

Title: High-Resolution Observations of Prominence Plume Formation
    with the New Vacuum Solar Telescope
Authors: Xue, Jianchao; Vial, Jean-Claude; Li, Hui; Xu, Zhi; Su,
   Yang; Su, Yingna
Bibcode: 2021cosp...43E.972X
Altcode: 2021arXiv210501293X
  Prominence plumes are evacuated upflows that emerge from bubbles
  below prominences, whose formation mechanism is still unclear. Here
  we present a detailed study of plumes in a quiescent prominence
  using the high--resolution H$\alpha$ spectral images from the New
  Vacuum Solar Telescope (NVST). Enhancements of brightening, blue
  shifts, and turbulence at the fronts of plumes are found during their
  formation. Some large plumes split at their heads and finger-shaped
  structures (type--I) are formed between them. At the late phases of
  the plumes, (type--II) fingers appear along the plume boundary where
  flows are strong. We found the flows along the prominence boundary
  occur before the plume formation. Our observations are consistent
  with the hypothesis that prominence plumes are related to coupled
  Kelvin--Helmholtz and Rayleigh--Taylor (KH/RT) instabilities. Plume
  splits and fingers are evidence of RT instability, and the flows
  along prominence boundary may increase the growth rate of KH/RT
  instabilities. A difference from previous explanation is that the RT
  instability is probably triggered by the plumes penetrating into the
  prominence. The significant turbulence at plume fronts is likely due
  to the collision between plumes and the prominence, and the fingers
  probably result from the KH/RT instabilities at the boundary of
  plumes and the prominence or the flows. Other causes of the plumes
  are discussed, including possible contribution of spicules underneath
  the prominence.

Title: Multiwavelength quiescent prominence spectroscopic observations
Authors: Zhang, Ping; Vial, Jean-Claude; Feng, Li; Curdt, Werner;
   Zapior, Maciej
Bibcode: 2021cosp...43E1770Z
Altcode:
  In the frame of the SUMER-IRIS HOP 334 campaign in March-April 2017,
  joint prominence observations have been performed with IRIS (Mg II
  h and k), SUMER (L-alpha) and HSFA2 ( Ondřejov Observatory) in Ca
  II K, H-beta and H-alpha. We proceeded first with the difficult
  task of coalignment i.e. identifying the pixels of the different
  slits corresponding to the same solar region observed at the same
  time. The selected profiles photometrically calibrated have been found
  non-reversed.Through the use of the NLTE radiative transfer code
  PRODOP available at MEDOC/IAS, we tentatively derive the 1D model
  fitting all observed profiles. The observed Lalpha profile found to
  be larger than the isothermal modelled one requires the addition of
  a PCTR. Some basic thermodynamical parameters are consequently derived.

Title: Observations of Solar Spicules at Millimeter and Ultraviolet
    Wavelengths
Authors: Bastian, T.; De Pontieu, B.; Shimojo, M.; Iwai, K.;
   Alissandrakis, C.; Nindos, A.; Vial, J. C.; White, S. M.
Bibcode: 2020AGUFMSH004..08B
Altcode:
  Solar spicules are a ubiquitous chromospheric phenomenon in which
  multitudes of dynamic jets with temperatures of order 10<SUP>4</SUP>
  K extend thousands of kilometers into the solar atmosphere. Recent
  progress has been made refining the observational characteristics
  of spicules using the Hinode Solar Optical Telescope (SOT) and the
  Interface Region Imaging Spectrograph (IRIS) observations at optical
  and ultraviolet wavelengths, respectively. Two types of spicule
  have been identified. Type I spicules, prevalent in solar active
  regions, have upward speeds of order 25 km/s and lifetimes of 3-7
  min. They may be the limb counterpart to shock-wave-driven fibrils
  commonly seen against the solar disk in active regions. In contrast,
  type II spicules, more common in quiet regions and coronal holes,
  display upward speeds of 50-150 km/s, lifetimes of 30-110 s, and
  appear to be partially heated to temperatures of 10<SUP>5 </SUP>K and
  higher. These observations have provoked intense interest in spicules
  and have led to proposals that type II spicules play a central role
  as a source of hot plasma in the corona. Nevertheless, their role in
  mass and energy transport between the lower and upper layers of the
  solar atmosphere remains an outstanding problem. <P />Here, we report
  imaging observations of solar spicules at millimeter wavelengths using
  the Atacama Large Millimeter-submillimeter Array (ALMA) with arcsecond
  angular resolution. Continuum millimeter wavelength radiation forms
  under conditions of local thermodynamic equilibrium, thereby providing a
  complementary tool to UV lines, which form under non-LTE conditions. The
  observations were made on 2018 December 24-25 at λ=1.25 mm and λ=3
  mm. The ALMA observations pose special challenges, particularly at
  1.25 mm, where the limited field of view of the instrument motivated
  us to use a novel mosaic imaging technique: multiple pointings were
  assembled to form a single map with an angular resolution of 1" x 0.7"
  on a cadence of roughly 2 min. In contrast, we were able to image at 3
  mm continuously, with a map cadence of 2 s and an angular resolution of
  2.3" x 1.3". <P />We compare and contrast the morphology and dynamics
  of mm-λ observations of spicules with those obtained by IRIS at UV
  wavelengths and place constraints on spicule temperatures and masses
  using the joint millimeter-wavelength observations.

Title: First results from combined EUI and SPICE observations of
    Lyman lines of Hydrogen and He II
Authors: Teriaca, L.; Aznar Cuadrado, R.; Giunta, A. S.; Grundy, T.;
   Parenti, S.; Auchere, F.; Vial, J. C.; Fludra, A.; Berghmans, D.;
   Carlsson, M.; Harra, L.; Hassler, D.; Long, D.; Peter, H.; Rochus,
   P. L.; Schühle, U.; Buchlin, E.; Caldwell, M.; Caminade, S.; DeForest,
   C.; Fredvik, T.; Gissot, S.; Heerlein, K.; Janvier, M.; Kraaikamp,
   E.; Kucera, T. A.; Mueller, D.; Schmutz, W. K.; Sidher, S.; Smith, P.;
   Stegen, K.; Thompson, W. T.; Verbeeck, C.; Williams, D.; Young, P. R.
Bibcode: 2020AGUFMSH0360003T
Altcode:
  The Solar Orbiter spacecraft carries a powerful set of remote
  sensing instruments that allow studying the solar atmosphere with
  unprecedented diagnostic capabilities. Many such diagnostics require
  the simultaneous usage of more than one instrument. One example of that
  is the capability, for the first time, to obtain (near) simultaneous
  spatially resolved observations of the emission from the first three
  lines of the Lyman series of hydrogen and of He II Lyman alpha. In fact,
  the SPectral Imaging of the Coronal Environment (SPICE) spectrometer
  can observe the Lyman beta and gamma lines in its long wavelength
  (SPICE-LW) channel, the High Resolution Lyman Alpha (HRI-LYA) telescope
  of the Extreme Ultraviolet Imager (EUI) acquires narrow band images in
  the Lyman alpha line while the Full Disk Imager (FSI) of EUI can take
  images dominated by the Lyman alpha line of ionized Helium at 30.4 nm
  (FSI-304). Being hydrogen and helium the main components of our star,
  these very bright transitions play an important role in the energy
  budget of the outer atmosphere via radiative losses and the measurement
  of their profiles and radiance ratios is a fundamental constraint to
  any comprehensive modelization effort of the upper solar chromosphere
  and transition region. Additionally, monitoring their average ratios
  can serve as a check out for the relative radiometric performance of
  the two instruments throughout the mission. Although the engineering
  data acquired so far are far from ideal in terms of time simultaneity
  (often only within about 1 h) and line coverage (often only Lyman beta
  was acquired by SPICE and not always near simultaneous images from all
  three telescopes are available) the analysis we present here still
  offers a great opportunity to have a first look at the potential of
  this diagnostic from the two instruments. In fact, we have identified
  a series of datasets obtained at disk center and at various positions
  at the solar limb that allow studying the Lyman alpha to beta radiance
  ratio and their relation to He II 30.4 as a function of the position
  on the Sun (disk center versus limb and quiet Sun versus coronal holes).

Title: The Solar Orbiter SPICE instrument. An extreme UV imaging
    spectrometer
Authors: SPICE Consortium; Anderson, M.; Appourchaux, T.; Auchère, F.;
   Aznar Cuadrado, R.; Barbay, J.; Baudin, F.; Beardsley, S.; Bocchialini,
   K.; Borgo, B.; Bruzzi, D.; Buchlin, E.; Burton, G.; Büchel, V.;
   Caldwell, M.; Caminade, S.; Carlsson, M.; Curdt, W.; Davenne, J.;
   Davila, J.; Deforest, C. E.; Del Zanna, G.; Drummond, D.; Dubau,
   J.; Dumesnil, C.; Dunn, G.; Eccleston, P.; Fludra, A.; Fredvik, T.;
   Gabriel, A.; Giunta, A.; Gottwald, A.; Griffin, D.; Grundy, T.; Guest,
   S.; Gyo, M.; Haberreiter, M.; Hansteen, V.; Harrison, R.; Hassler,
   D. M.; Haugan, S. V. H.; Howe, C.; Janvier, M.; Klein, R.; Koller,
   S.; Kucera, T. A.; Kouliche, D.; Marsch, E.; Marshall, A.; Marshall,
   G.; Matthews, S. A.; McQuirk, C.; Meining, S.; Mercier, C.; Morris,
   N.; Morse, T.; Munro, G.; Parenti, S.; Pastor-Santos, C.; Peter, H.;
   Pfiffner, D.; Phelan, P.; Philippon, A.; Richards, A.; Rogers, K.;
   Sawyer, C.; Schlatter, P.; Schmutz, W.; Schühle, U.; Shaughnessy,
   B.; Sidher, S.; Solanki, S. K.; Speight, R.; Spescha, M.; Szwec, N.;
   Tamiatto, C.; Teriaca, L.; Thompson, W.; Tosh, I.; Tustain, S.; Vial,
   J. -C.; Walls, B.; Waltham, N.; Wimmer-Schweingruber, R.; Woodward,
   S.; Young, P.; de Groof, A.; Pacros, A.; Williams, D.; Müller, D.
Bibcode: 2020A&A...642A..14S
Altcode: 2019arXiv190901183A; 2019arXiv190901183S
  <BR /> Aims: The Spectral Imaging of the Coronal Environment (SPICE)
  instrument is a high-resolution imaging spectrometer operating at
  extreme ultraviolet wavelengths. In this paper, we present the concept,
  design, and pre-launch performance of this facility instrument on the
  ESA/NASA Solar Orbiter mission. <BR /> Methods: The goal of this paper
  is to give prospective users a better understanding of the possible
  types of observations, the data acquisition, and the sources that
  contribute to the instrument's signal. <BR /> Results: The paper
  discusses the science objectives, with a focus on the SPICE-specific
  aspects, before presenting the instrument's design, including optical,
  mechanical, thermal, and electronics aspects. This is followed by a
  characterisation and calibration of the instrument's performance. The
  paper concludes with descriptions of the operations concept and data
  processing. <BR /> Conclusions: The performance measurements of the
  various instrument parameters meet the requirements derived from the
  mission's science objectives. The SPICE instrument is ready to perform
  measurements that will provide vital contributions to the scientific
  success of the Solar Orbiter mission.

Title: The Solar Orbiter EUI instrument: The Extreme Ultraviolet
    Imager
Authors: Rochus, P.; Auchère, F.; Berghmans, D.; Harra, L.; Schmutz,
   W.; Schühle, U.; Addison, P.; Appourchaux, T.; Aznar Cuadrado,
   R.; Baker, D.; Barbay, J.; Bates, D.; BenMoussa, A.; Bergmann, M.;
   Beurthe, C.; Borgo, B.; Bonte, K.; Bouzit, M.; Bradley, L.; Büchel,
   V.; Buchlin, E.; Büchner, J.; Cabé, F.; Cadiergues, L.; Chaigneau,
   M.; Chares, B.; Choque Cortez, C.; Coker, P.; Condamin, M.; Coumar,
   S.; Curdt, W.; Cutler, J.; Davies, D.; Davison, G.; Defise, J. -M.;
   Del Zanna, G.; Delmotte, F.; Delouille, V.; Dolla, L.; Dumesnil, C.;
   Dürig, F.; Enge, R.; François, S.; Fourmond, J. -J.; Gillis, J. -M.;
   Giordanengo, B.; Gissot, S.; Green, L. M.; Guerreiro, N.; Guilbaud,
   A.; Gyo, M.; Haberreiter, M.; Hafiz, A.; Hailey, M.; Halain, J. -P.;
   Hansotte, J.; Hecquet, C.; Heerlein, K.; Hellin, M. -L.; Hemsley, S.;
   Hermans, A.; Hervier, V.; Hochedez, J. -F.; Houbrechts, Y.; Ihsan,
   K.; Jacques, L.; Jérôme, A.; Jones, J.; Kahle, M.; Kennedy, T.;
   Klaproth, M.; Kolleck, M.; Koller, S.; Kotsialos, E.; Kraaikamp, E.;
   Langer, P.; Lawrenson, A.; Le Clech', J. -C.; Lenaerts, C.; Liebecq,
   S.; Linder, D.; Long, D. M.; Mampaey, B.; Markiewicz-Innes, D.;
   Marquet, B.; Marsch, E.; Matthews, S.; Mazy, E.; Mazzoli, A.; Meining,
   S.; Meltchakov, E.; Mercier, R.; Meyer, S.; Monecke, M.; Monfort,
   F.; Morinaud, G.; Moron, F.; Mountney, L.; Müller, R.; Nicula, B.;
   Parenti, S.; Peter, H.; Pfiffner, D.; Philippon, A.; Phillips, I.;
   Plesseria, J. -Y.; Pylyser, E.; Rabecki, F.; Ravet-Krill, M. -F.;
   Rebellato, J.; Renotte, E.; Rodriguez, L.; Roose, S.; Rosin, J.;
   Rossi, L.; Roth, P.; Rouesnel, F.; Roulliay, M.; Rousseau, A.; Ruane,
   K.; Scanlan, J.; Schlatter, P.; Seaton, D. B.; Silliman, K.; Smit,
   S.; Smith, P. J.; Solanki, S. K.; Spescha, M.; Spencer, A.; Stegen,
   K.; Stockman, Y.; Szwec, N.; Tamiatto, C.; Tandy, J.; Teriaca, L.;
   Theobald, C.; Tychon, I.; van Driel-Gesztelyi, L.; Verbeeck, C.;
   Vial, J. -C.; Werner, S.; West, M. J.; Westwood, D.; Wiegelmann, T.;
   Willis, G.; Winter, B.; Zerr, A.; Zhang, X.; Zhukov, A. N.
Bibcode: 2020A&A...642A...8R
Altcode:
  Context. The Extreme Ultraviolet Imager (EUI) is part of the remote
  sensing instrument package of the ESA/NASA Solar Orbiter mission
  that will explore the inner heliosphere and observe the Sun from
  vantage points close to the Sun and out of the ecliptic. Solar Orbiter
  will advance the "connection science" between solar activity and the
  heliosphere. <BR /> Aims: With EUI we aim to improve our understanding
  of the structure and dynamics of the solar atmosphere, globally as well
  as at high resolution, and from high solar latitude perspectives. <BR />
  Methods: The EUI consists of three telescopes, the Full Sun Imager and
  two High Resolution Imagers, which are optimised to image in Lyman-α
  and EUV (17.4 nm, 30.4 nm) to provide a coverage from chromosphere
  up to corona. The EUI is designed to cope with the strong constraints
  imposed by the Solar Orbiter mission characteristics. Limited telemetry
  availability is compensated by state-of-the-art image compression,
  onboard image processing, and event selection. The imposed power
  limitations and potentially harsh radiation environment necessitate
  the use of novel CMOS sensors. As the unobstructed field of view of
  the telescopes needs to protrude through the spacecraft's heat shield,
  the apertures have been kept as small as possible, without compromising
  optical performance. This led to a systematic effort to optimise the
  throughput of every optical element and the reduction of noise levels
  in the sensor. <BR /> Results: In this paper we review the design
  of the two elements of the EUI instrument: the Optical Bench System
  and the Common Electronic Box. Particular attention is also given to
  the onboard software, the intended operations, the ground software,
  and the foreseen data products. <BR /> Conclusions: The EUI will
  bring unique science opportunities thanks to its specific design,
  its viewpoint, and to the planned synergies with the other Solar
  Orbiter instruments. In particular, we highlight science opportunities
  brought by the out-of-ecliptic vantage point of the solar poles,
  the high-resolution imaging of the high chromosphere and corona,
  and the connection to the outer corona as observed by coronagraphs.

Title: Metis: the Solar Orbiter visible light and ultraviolet
    coronal imager
Authors: Antonucci, Ester; Romoli, Marco; Andretta, Vincenzo; Fineschi,
   Silvano; Heinzel, Petr; Moses, J. Daniel; Naletto, Giampiero; Nicolini,
   Gianalfredo; Spadaro, Daniele; Teriaca, Luca; Berlicki, Arkadiusz;
   Capobianco, Gerardo; Crescenzio, Giuseppe; Da Deppo, Vania; Focardi,
   Mauro; Frassetto, Fabio; Heerlein, Klaus; Landini, Federico; Magli,
   Enrico; Marco Malvezzi, Andrea; Massone, Giuseppe; Melich, Radek;
   Nicolosi, Piergiorgio; Noci, Giancarlo; Pancrazzi, Maurizio; Pelizzo,
   Maria G.; Poletto, Luca; Sasso, Clementina; Schühle, Udo; Solanki,
   Sami K.; Strachan, Leonard; Susino, Roberto; Tondello, Giuseppe;
   Uslenghi, Michela; Woch, Joachim; Abbo, Lucia; Bemporad, Alessandro;
   Casti, Marta; Dolei, Sergio; Grimani, Catia; Messerotti, Mauro;
   Ricci, Marco; Straus, Thomas; Telloni, Daniele; Zuppella, Paola;
   Auchère, Frederic; Bruno, Roberto; Ciaravella, Angela; Corso,
   Alain J.; Alvarez Copano, Miguel; Aznar Cuadrado, Regina; D'Amicis,
   Raffaella; Enge, Reiner; Gravina, Alessio; Jejčič, Sonja; Lamy,
   Philippe; Lanzafame, Alessandro; Meierdierks, Thimo; Papagiannaki,
   Ioanna; Peter, Hardi; Fernandez Rico, German; Giday Sertsu, Mewael;
   Staub, Jan; Tsinganos, Kanaris; Velli, Marco; Ventura, Rita; Verroi,
   Enrico; Vial, Jean-Claude; Vives, Sebastien; Volpicelli, Antonio;
   Werner, Stephan; Zerr, Andreas; Negri, Barbara; Castronuovo, Marco;
   Gabrielli, Alessandro; Bertacin, Roberto; Carpentiero, Rita; Natalucci,
   Silvia; Marliani, Filippo; Cesa, Marco; Laget, Philippe; Morea, Danilo;
   Pieraccini, Stefano; Radaelli, Paolo; Sandri, Paolo; Sarra, Paolo;
   Cesare, Stefano; Del Forno, Felice; Massa, Ernesto; Montabone, Mauro;
   Mottini, Sergio; Quattropani, Daniele; Schillaci, Tiziano; Boccardo,
   Roberto; Brando, Rosario; Pandi, Arianna; Baietto, Cristian; Bertone,
   Riccardo; Alvarez-Herrero, Alberto; García Parejo, Pilar; Cebollero,
   María; Amoruso, Mauro; Centonze, Vito
Bibcode: 2020A&A...642A..10A
Altcode: 2019arXiv191108462A
  <BR /> Aims: Metis is the first solar coronagraph designed for a
  space mission and is capable of performing simultaneous imaging of the
  off-limb solar corona in both visible and UV light. The observations
  obtained with Metis aboard the Solar Orbiter ESA-NASA observatory
  will enable us to diagnose, with unprecedented temporal coverage and
  spatial resolution, the structures and dynamics of the full corona
  in a square field of view (FoV) of ±2.9° in width, with an inner
  circular FoV at 1.6°, thus spanning the solar atmosphere from 1.7
  R<SUB>⊙</SUB> to about 9 R<SUB>⊙</SUB>, owing to the eccentricity
  of the spacecraft orbit. Due to the uniqueness of the Solar Orbiter
  mission profile, Metis will be able to observe the solar corona
  from a close (0.28 AU, at the closest perihelion) vantage point,
  achieving increasing out-of-ecliptic views with the increase of the
  orbit inclination over time. Moreover, observations near perihelion,
  during the phase of lower rotational velocity of the solar surface
  relative to the spacecraft, allow longer-term studies of the off-limb
  coronal features, thus finally disentangling their intrinsic evolution
  from effects due to solar rotation. <BR /> Methods: Thanks to a novel
  occultation design and a combination of a UV interference coating of
  the mirrors and a spectral bandpass filter, Metis images the solar
  corona simultaneously in the visible light band, between 580 and 640
  nm, and in the UV H I Lyman-α line at 121.6 nm. The visible light
  channel also includes a broadband polarimeter able to observe the
  linearly polarised component of the K corona. The coronal images in
  both the UV H I Lyman-α and polarised visible light are obtained at
  high spatial resolution with a spatial scale down to about 2000 km
  and 15 000 km at perihelion, in the cases of the visible and UV light,
  respectively. A temporal resolution down to 1 s can be achieved when
  observing coronal fluctuations in visible light. <BR /> Results: The
  Metis measurements, obtained from different latitudes, will allow for
  complete characterisation of the main physical parameters and dynamics
  of the electron and neutral hydrogen/proton plasma components of the
  corona in the region where the solar wind undergoes the acceleration
  process and where the onset and initial propagation of coronal mass
  ejections (CMEs) take place. The near-Sun multi-wavelength coronal
  imaging performed with Metis, combined with the unique opportunities
  offered by the Solar Orbiter mission, can effectively address crucial
  issues of solar physics such as: the origin and heating/acceleration
  of the fast and slow solar wind streams; the origin, acceleration,
  and transport of the solar energetic particles; and the transient
  ejection of coronal mass and its evolution in the inner heliosphere,
  thus significantly improving our understanding of the region connecting
  the Sun to the heliosphere and of the processes generating and driving
  the solar wind and coronal mass ejections. <BR /> Conclusions: This
  paper presents the scientific objectives and requirements, the overall
  optical design of the Metis instrument, the thermo-mechanical design,
  and the processing and power unit; reports on the results of the
  campaigns dedicated to integration, alignment, and tests, and to
  the characterisation of the instrument performance; describes the
  operation concept, data handling, and software tools; and, finally,
  the diagnostic techniques to be applied to the data, as well as a brief
  description of the expected scientific products. The performance of the
  instrument measured during calibrations ensures that the scientific
  objectives of Metis can be pursued with success. <P />Metis website:
  <A href="http://metis.oato.inaf.it">http://metis.oato.inaf.it</A>

Title: New Light on an Old Problem of the Cores of Solar Resonance
    Lines
Authors: Judge, Philip G.; Kleint, Lucia; Leenaarts, Jorrit;
   Sukhorukov, Andrii V.; Vial, Jean-Claude
Bibcode: 2020ApJ...901...32J
Altcode: 2020arXiv200801250J
  We reexamine a 50+ yr old problem of deep central reversals predicted
  for strong solar spectral lines, in contrast to the smaller reversals
  seen in observations. We examine data and calculations for the resonance
  lines of H I, Mg II, and Ca II, the self-reversed cores of which form
  in the upper chromosphere. Based on 3D simulations, as well as data for
  the Mg II lines from the Interface Region Imaging Spectrograph (IRIS),
  we argue that the resolution lies not in velocity fields on scales in
  either of the micro- or macroturbulent limits. Macroturbulence is ruled
  out using observations of optically thin lines formed in the upper
  chromosphere, and by showing that it would need to have unreasonably
  special properties to account for critical observations of the Mg
  II resonance lines from the IRIS mission. The power in "turbulence"
  in the upper chromosphere may therefore be substantially lower than
  earlier analyses have inferred. Instead, in 3D calculations horizontal
  radiative transfer produces smoother source functions, smoothing out
  intensity gradients in wavelength and in space. These effects increase
  in stronger lines. Our work will have consequences for understanding
  the onset of the transition region, for understanding the energy in
  motions available for heating the corona, and for the interpretation
  of polarization data in terms of the Hanle effect applied to resonance
  line profiles.

Title: The synergy between the payloads on the ASO-S mission
Authors: Vial, Jean-Claude
Bibcode: 2019RAA....19..166V
Altcode:
  This paper addresses the improved science resulting from joint
  observations performed by the different instruments onboard the Advanced
  Space-based Solar Observatory (ASO-S) mission along with ancillary
  instruments on missions flying at the same time. It first describes
  the three major instruments along with their stated objectives. Then it
  presents some basic science issues concerning jointly observed flares,
  coronal mass ejections (CMEs) and eruptive prominences (EPs). Each
  physical candidate (magnetic reconnection, instability, hard X-ray
  emission and magnetic coronal field topology) is discussed in terms
  of its signature and identification with ASO-S instrumentation. The
  importance of Lyα detection and non-LTE modeling is stressed. Some
  instrumental and science challenges are briefly discussed.

Title: Elemental composition in quiescent prominences
Authors: Parenti, S.; Del Zanna, G.; Vial, J. -C.
Bibcode: 2019A&A...625A..52P
Altcode: 2019arXiv190500871P
  Context. The first ionization potential (FIP) bias is currently used
  to trace the propagation of solar features ejected by the wind and
  solar eruptions (coronal mass ejections). The FIP bias also helps us to
  understand the formation of prominences, as it is a tracer for the solar
  origin of prominence plasma. <BR /> Aims: This work aims to provide
  elemental composition and FIP bias in quiescent solar prominences. This
  is key information to link these features to remnants of solar eruptions
  measured in-situ within the heliosphere and to constrain the coronal or
  photospheric origin of prominence plasma. <BR /> Methods: We used the
  differential emission measure technique to derive the FIP bias of two
  prominences. Quiet Sun chromospheric and transition region data were
  used to test the atomic data and lines formation processes. We used
  lines from low stage of ionization of Si, S, Fe, C, N, O, Ni, Mg, and
  Ne, constraining the FIP bias in the range 4.2 ≤ log T ≤ 5.8. We
  adopted a density-dependent ionization equilibrium. <BR /> Results:
  We showed that the two prominences have photospheric composition. We
  confirmed a photospheric composition in the quiet Sun. We also
  identified opacity and/or radiative excitation contributions to the
  line formation of a few lines regularly observed in prominences. <BR />
  Conclusions: With our results we thus provide important elements for
  correctly interpreting the upcoming Solar Orbiter/SPICE spectroscopic
  data and to constrain prominence formation.

Title: Elemental composition in quiescent prominences
Authors: Parenti, Susanna; Del Zanna, Giulio; Vial, Jean-Claude
Bibcode: 2019shin.confE.182P
Altcode:
  The first ionization potential (FIP) bias is currently used to trace the
  propagation of solar features ejected by the wind and solar eruptions
  (coronal mass ejections). The FIP bias also helps us to understand
  the formation of prominences, as it is a tracer for the solar origin
  of prominence plasma. This work aims to provide elemental composition
  and FIP bias in quiescent solar prominences. This is key information
  to link these features to remnants of solar eruptions measured in-situ
  within the heliosphere and to constrain the coronal or photospheric
  origin of prominence plasma. We used the differential emission measure
  technique to derive the FIP bias of two prominences observed with
  SOHO/SUMER. Quiet Sun chromospheric and transition region data were
  used to test the atomic data and lines formation processes. We used
  lines from low stage of ionization of Si, S, Fe, C, N, O, Ni, Mg, and
  Ne, constraining the FIP bias in the range 4.2 &lt; log T&lt; 5.8. We
  adopted a density-dependent ionization equilibrium. We showed that
  the two prominences have photospheric composition. We also identified
  opacity and/or radiative excitation contributions to the line formation
  of a few lines regularly observed in prominences. With our results
  we thus provide important elements for correctly interpreting the
  upcoming Solar Orbiter/SPICE spectroscopic data and to constrain
  prominence formation.

Title: Some relationships between radiative and atmospheric quantities
    through 1D NLTE modeling of prominences in the Mg II lines
Authors: Vial, J. -C.; Zhang, P.; Buchlin, É.
Bibcode: 2019A&A...624A..56V
Altcode:
  Context. With more than four years of IRIS observations, and in order
  to avoid building customized diagnostics for each observation, it is
  useful to derive some simple relations between spectra and physical
  quantities. This is even more useful for the k and h lines of Mg
  II, which require complex non-local-thermodynamic-equilibrium NLTE
  treatments. <BR /> Aims: The aim of this work concerning prominences
  is to correlate observable spectral features in h and k lines of Mg II
  to physical quantities such as the density and the emission measure
  (EM) in the same way as similar correlations have been obtained in
  the hydrogen lines. In this way, and within approximations done on
  some parameters such as temperature, it is possible to build pixel by
  pixel an IRIS map of the above-mentioned quantities. <BR /> Methods:
  In order to simplify and shorten the modeling, we chose to compute
  one-dimensional (1D) isothermal and isobaric models that are treated
  with the PROM7 NLTE code available at MEDOC (IAS). We built a set of
  models with large ranges of temperature, pressure, and thickness. At
  all altitudes considered, we paid attention to the exact computation
  of the incident radiation. Then we compared the emergent Mg II h and k
  intensities with the corresponding hydrogen and electron densities and
  EMs. <BR /> Results: From the NLTE computation, we derive correlations
  between the k and h emergent intensities on one hand and the densities
  and EM on the other hand. With some assumptions on the temperature,
  we obtain a unique relation between the k (and h) intensities and the
  EM that should be useful for deriving either the hydrogen and electron
  densities or the effective thickness of an observed prominence. <BR
  /> Conclusions: From NLTE modeling, we have provided a relationship
  between observable integrated intensities of the Mg II resonance
  lines and prominence plasma EM, which will contribute to a first-order
  analysis of long time series of spectroscopic observations, for example,
  with IRIS. We anticipate building more complex relations between the
  profiles and other plasma quantities.

Title: Launch of a CME-associated eruptive prominence as observed
    with IRIS and ancillary instruments
Authors: Zhang, P.; Buchlin, É.; Vial, J. -C.
Bibcode: 2019A&A...624A..72Z
Altcode:
  <BR /> Aims: In this paper we focus on the possible observational
  signatures of the processes which have been put forward for explaining
  eruptive prominences. We also try to understand the variations in the
  physical conditions of eruptive prominences and estimate the masses
  leaving the Sun versus the masses returning to the Sun during eruptive
  prominences. <BR /> Methods: As far as velocities are concerned, we
  combined an optical flow method on the Atmospheric Imaging Assembly
  (AIA) 304 Å and Interface Region Imaging Spectrograph (IRIS). Mg II
  h&amp;k observations in order to derive the plane-of-sky velocities
  in the prominence, and a Doppler technique on the IRIS Mg II h&amp;k
  profiles to compute the line-of-sight velocities. As far as densities
  are concerned, we compared the absolute observed intensities with values
  derived from non-local thermodynamic equilibrium radiative transfer
  computations to derive the total (hydrogen) density and consequently
  compute the mass flows. <BR /> Results: The derived electron
  densities range from 1.3 × 10<SUP>9</SUP> to 6.0 × 10<SUP>10</SUP>
  cm<SUP>-3</SUP> and the derived total hydrogen densities range from
  1.5 × 10<SUP>9</SUP> to 2.4 × 10<SUP>11</SUP> cm<SUP>-3</SUP>
  in different regions of the prominence. The mean temperature is
  around 1.1 × 10<SUP>4</SUP> K, which is higher than in quiescent
  prominences. The ionization degree is in the range of 0.1-10. The
  total (hydrogen) mass is in the range of 1.3 × 10<SUP>14</SUP>-3.2
  × 10<SUP>14</SUP> g. The total mass drainage from the prominence
  to the solar surface during the whole observation time of IRIS is
  about one order of magnitude smaller than the total mass of the
  prominence. <P />The movie associated to Fig. 2 is available at <A
  href="https://www.aanda.org/10.1051/0004-6361/201834259/olm">https://www.aanda.org</A>

Title: Preface
Authors: Engvold, Oddbjørn; Vial, Jean-Claude; Skumanich, Andrew
Bibcode: 2019sgsp.bookD..17E
Altcode:
  No abstract at ADS

Title: Chapter 14 - Challenges and Prospects for the Future
Authors: Vial, Jean-Claude; Skumanich, Andrew
Bibcode: 2019sgsp.book..463V
Altcode:
  The 14 chapters (and five subchapters) of this book have addressed
  only a few aspects of the many works that have been produced during the
  latest decades in the domain of solar physics and that may be relevant
  to stellar physics and possibly other fields in astrophysics. The
  achievements result not only from the proximity of our star, which
  allows for detailed and comprehensive observations but also from the
  many questions that have arisen and have been answered through the
  implications of physics and sometimes have led to the stimulation of a
  "new" physics. <P />We do not include the summaries and conclusions of
  these 14 chapters here. We simply focus on a few points (challenges and
  prospects) that may be of interest for future progress and discoveries
  in solar and stellar physics. As is shown here, we also allow ourselves
  to point out that some authors of the book, including ourselves, may
  have some different views on a few topics, a fact of life in science. We
  address the various issues with the two following questions in mind:
  Where and how is solar progress foreseen? What are the mutual benefits
  in the solar-stellar connection?

Title: The Sun as a Guide to Stellar Physics
Authors: Engvold, Oddbjørn; Vial, Jean-Claude; Skumanich, Andrew
Bibcode: 2019sgsp.book.....E
Altcode:
  No abstract at ADS

Title: Effects of resonant scattering of the Si IV doublet near 140
    nm in a solar active region
Authors: Gontikakis, C.; Vial, J. -C.
Bibcode: 2018A&A...619A..64G
Altcode:
  <BR /> Aims: In a previous study we analysed the C IV 1548.189 Å and
  1550.775 Å lines observed with the Solar Ultraviolet Measurements
  of Emitted Radiation (SUMER), showing cases where the 1548.189 Å
  spectral profile was noticeably different from the 1550.775 Å one,
  profiles that we dubbed differentially shaped profiles. We explained
  this differential behaviour by an important radiative contribution,
  affecting multiple plasma motions happening at the instrument
  sub-resolution scale. In the present study we examine more general
  cases where radiative effects may contribute to the emission from
  the transition region of an active region. Here we analyse the
  lines Si IV 1393.757 Å and 1402.772 Å observed with the Interface
  Region Imaging Spectrograph (IRIS). <BR /> Methods: We study active
  region NOAA 12529, observed with IRIS on 18 April 2016. Using sorting
  techniques we selected individual profiles for which the intensity line
  ratio 1393.757 Å/1402.772 Å is significantly higher or lower than
  2 and we also tracked differentially shaped profiles. We analyse the
  physical conditions that create these profiles and in some cases we
  estimate electron densities. <BR /> Results: We found more than 4000
  individual profiles with line ratios higher than 2, about 500 profiles
  for which the line ratio is in the range 1.3-1.6, and 15 differentially
  shaped profiles. Line ratios higher than 2, are found along loops, and
  mostly at the y = 250 to 300″ part of the plage. There, we estimated
  the incident radiation and derived electron densities that can vary
  from 10<SUP>9</SUP> to a few times 10<SUP>11</SUP> cm<SUP>-3</SUP>,
  depending on the plasma temperature. For the low line ratios, the
  sources are concentrated at the periphery of the active region plage,
  mostly along fibrils and present optical depths, τ, between 1.5 and
  3. in most cases. The electron densities calculated from these Si IV
  profiles are comparable with electron densities derived using the
  O IV 1399.766 Å-1401.163 Å ratios. <BR /> Conclusions: We found
  that about 2.4% of the individual profiles for which we can perform
  a Gaussian fit present a line ratio higher than 2. In profiles with
  a high line ratio, the resonant scattering appears to be due to the
  combination of an average incident radiation field with a relatively
  low local electron density and not due to the vicinity of an ephemeral
  strong light source. As far as low intensity ratios are concerned,
  non-negligible optical depths are found at the edge of the plage,
  near the footpoints of fibrils that are oriented towards quiet
  Sun areas, where the electron density can be as high as (7 - 9) ×
  10<SUP>11</SUP> cm<SUP>-3</SUP> if we assume a plasma in ionization
  equilibrium. <P />The movie associated to Fig. 3 is only available at <A
  href="https://www.aanda.org/10.1051/0004-6361/201732563/olm">https://www.aanda.org</A>

Title: First high-resolution look at the quiet Sun with ALMA at 3mm
Authors: Nindos, A.; Alissandrakis, C. E.; Bastian, T. S.; Patsourakos,
   S.; De Pontieu, B.; Warren, H.; Ayres, T.; Hudson, H. S.; Shimizu,
   T.; Vial, J. -C.; Wedemeyer, S.; Yurchyshyn, V.
Bibcode: 2018A&A...619L...6N
Altcode: 2018arXiv181005223N
  We present an overview of high-resolution quiet Sun observations,
  from disk center to the limb, obtained with the Atacama Large
  millimeter and sub-millimeter Array (ALMA) at 3 mm. Seven quiet-Sun
  regions were observed at a resolution of up to 2.5″ by 4.5″. We
  produced both average and snapshot images by self-calibrating the ALMA
  visibilities and combining the interferometric images with full-disk
  solar images. The images show well the chromospheric network, which,
  based on the unique segregation method we used, is brighter than the
  average over the fields of view of the observed regions by ∼305
  K while the intranetwork is less bright by ∼280 K, with a slight
  decrease of the network/intranetwork contrast toward the limb. At 3
  mm the network is very similar to the 1600 Å images, with somewhat
  larger size. We detect, for the first time, spicular structures,
  rising up to 15″ above the limb with a width down to the image
  resolution and brightness temperature of ∼1800 K above the local
  background. No trace of spicules, either in emission or absorption,
  is found on the disk. Our results highlight the potential of ALMA for
  the study of the quiet chromosphere.

Title: Cool Material in the Hot Solar Corona and the
    Chromosphere-Corona Mass Cycle
Authors: Liu, Wei; Vial, Jean-Claude; Antolin, Patrick; Sun, Xudong;
   Berger, Thomas
Bibcode: 2018cosp...42E2052L
Altcode:
  In the million-degree hot and tenuous solar corona, under favorable
  conditions, some mass can undergo a radiative cooling instability and
  condense into material of 100 times cooler in two distinct forms -
  prominences and coronal rain. Being at similar temperatures, they
  exhibit contrasting morphologies and behaviors: a quiescent prominence
  usually consists of numerous long-lasting, filamentary downflow
  threads, while coronal rain consists of transient mass blobs falling
  at comparably higher speeds along well-defined, curved paths (e.g.,
  guided by coronal loops). We report recent imaging and spectroscopic
  observations from SDO/AIA and IRIS of a hybrid prominence-coronal
  rain complex structure that suggest different magnetic environments
  being responsible for such distinctions. We also present an ensemble
  of observations of the so-called funnel prominences that reside near
  the dips of magnetic funnels. Regardless of their morphological and
  behavioral differences, a large fraction of prominence and coronal
  rain material eventually falls back to the chromosphere and serves as
  the return flow of the so-called chromosphere-corona mass cycle (the
  other half of this cycle is the upward transport of heated mass from
  the chromosphere to the corona). We estimate the downflow mass fluxes
  in prominences and coronal rain, and compare them with the coronal
  mass budget in this cycle and with the mass loss to the solar wind
  and coronal mass ejections (CMEs). We will discuss the broad physical
  implications of these observations for fundamental questions, such as
  coronal heating and beyond.

Title: An analysis of simultaneous observations of a CME-associated
    eruptive prominence with IRIS, AIA/SDO, EUVI/STEREO and K-COR
Authors: Zhang, Ping; Vial, Jean-Claude; Buchlin, Eric
Bibcode: 2018cosp...42E3836Z
Altcode:
  We present the simultaneous observations of a CME-associated eruptive
  prominence which have been made by the Interface Region Imaging
  Spectrograph (IRIS), Atmospheric Imaging Assembly (AIA) of SDO, EUVI
  of STEREO and the ground-based K-COR coronagraph. IRIS observations
  started on 2014 May 28 at 11:25 UT, lasted for about 4.5 hours. With
  the aim of deriving the velocity vector, we first combined an optical
  flow method on the AIA 304 observations to compute the POS velocities
  in the prominence and a Doppler technique with the IRIS observations
  to compute the LOS velocities. Then we characterized the Mg h and k
  profiles (time and space-dependent) and compared with the signatures
  of various (1000) prominence models through NLTE radiative transfer
  computations (I.A.S. PROM7 code). We paid much attention to the exact
  incident radiation in various lines and continua. The model parameters
  include pressure, temperature, height, thickness, radial and turbulence
  velocities. Having selected the best (fitting) models, we were able
  to derive the total (hydrogen) density and compute the mass flows. We
  also used the STEREO observations to derive the 3D geometry of the
  prominence and K-COR to derive the density later on in the process of
  eruption. Applying this method to more prominences observed by IRIS
  could help to reduce the large range of thermodynamic parameters in
  eruptive prominences and to improve their MHD modeling.

Title: Chemical fractionation in solar prominences
Authors: Parenti, Susanna; Vial, Jean-Claude; Del Zanna, Giulio
Bibcode: 2018cosp...42E2585P
Altcode:
  The First Ionization Potential (FIP) fractionation of elemental
  abundances in the solar atmosphere and solar wind is a known process
  which appears to vary depending on the magnetic field property and
  the dynamic nature of the environment. It is generally identified
  by an increase of the low FIP elements (with FIP energy below 10 eV)
  compared to the high FIP elements (with respect to the photospheric
  values). For instance, the low FIP element abundance is enhanced
  within active regions by about a factor of 3-4, with respect to
  photospheric values. A similar property is measured in the slow
  solar wind. This is one of the reasons why the FIP fractionation is
  used as a proxy for identifying the solar wind source regions on the
  Sun, a topic of particular relevance for the upcoming Solar Orbiter
  mission.Cool, low-state ionized plasma and its composition have been
  measured in-situ within interplanetary Coronal Mass Ejections (ICMEs)
  in only a few cases. This cool plasma has been associated to remnants
  of erupting prominences. However, this association is not confirmed,
  because the measurement of the composition within prominence plasma is
  very difficult and poorly known. The scope of this paper is to provide
  a reliable measurement of elements composition and FIP fractionation in
  a prominence using the available SOHO/SUMER dataset of the prominence
  atlas presented in Parenti et. al 2005. Our investigation will consider
  ions formed in the prominence-corona transition region, taking into
  account possible density and opacity effects in the formation of the
  spectral lines.

Title: Physical conditions in a prominence eruption during its
    pre-eruption and acceleration
Authors: Zhang, Ping; Vial, Jean-Claude; Buchlin, Eric
Bibcode: 2018cosp...42E3837Z
Altcode:
  We rely upon the simultaneous observations of a CME-associated
  eruptive prominence which have been made by the Interface Region
  Imaging Spectrograph (IRIS), Atmospheric Imaging Assembly (AIA) of
  SDO, EUVI of STEREO and the ground-based K-COR coronagraph. We focus
  on the determination of mass flows in order to detect a possible mass
  loading. In order to derive the full velocity vector, we combine an
  optical flow method on the AIA 304 and IRIS SJI observations to compute
  the POS velocities in the prominence and a Doppler technique with the
  IRIS observations to compute the LOS velocities. Then we focus on the
  determination of densities through the combination of spectroscopic
  observations and NLTE modelling. We first characterize the Mg II h and
  k profiles (time and space-dependent!) through a grid of 6 typical
  profiles (reversed and unreversed). Then we compare them with the
  signatures of hundreds of prominence models through NLTE radiative
  transfer computations (I.A.S. PROM7 code). Much attention is paid to
  the exact incident radiation in various lines and continua. Having
  selected the best (fitting) models, we are able to derive the total
  (hydrogen) density and compute the mass flows. The derivation of
  physical parameters (e.g. velocity) also takes into account the STEREO
  observations to derive the 3D geometry of the prominence and K-COR to
  derive the density later on in the process of eruption.

Title: IRIS Observations of Spicules and Structures Near the
    Solar Limb
Authors: Alissandrakis, C. E.; Vial, J. -C.; Koukras, A.; Buchlin,
   E.; Chane-Yook, M.
Bibcode: 2018SoPh..293...20A
Altcode: 2018arXiv180102082A
  We have analyzed Interface Region Imaging Spectrograph (IRIS)
  spectral and slit-jaw observations of a quiet region near the South
  Pole. In this article we present an overview of the observations, the
  corrections, and the absolute calibration of the intensity. We focus
  on the average profiles of strong (Mg II h and k, C II and Si IV),
  as well as of weak spectral lines in the near ultraviolet (NUV) and
  the far ultraviolet (FUV), including the Mg II triplet, thus probing
  the solar atmosphere from the low chromosphere to the transition
  region. We give the radial variation of bulk spectral parameters as
  well as line ratios and turbulent velocities. We present measurements
  of the formation height in lines and in the NUV continuum from which
  we find a linear relationship between the position of the limb and
  the intensity scale height. We also find that low forming lines,
  such as the Mg II triplet, show no temporal variations above the limb
  associated with spicules, suggesting that such lines are formed in a
  homogeneous atmospheric layer and, possibly, that spicules are formed
  above the height of 2<SUP>″</SUP>. We discuss the spatio-temporal
  structure of the atmosphere near the limb from images of intensity as
  a function of position and time. In these images, we identify p-mode
  oscillations in the cores of lines formed at low heights above the
  photosphere, slow-moving bright features in O I and fast-moving bright
  features in C II. Finally, we compare the Mg II k and h line profiles,
  together with intensity values of the Balmer lines from the literature,
  with computations from the PROM57Mg non-LTE model, developed at the
  Institut d' Astrophysique Spatiale, and estimated values of the physical
  parameters. We obtain electron temperatures in the range of ∼8000 K
  at small heights to ∼20 000 K at large heights, electron densities
  from 1.1 ×10<SUP>11</SUP> to 4 ×10<SUP>10</SUP>cm−<SUP>3</SUP>
  and a turbulent velocity of ∼24 kms−<SUP>1</SUP>.

Title: EUV imager and spectrometer for LYOT and solar orbiter space
    missions
Authors: Millard, Anne; Lemaire, Philippe; Vial, Jean-Claude
Bibcode: 2017SPIE10568E..0RM
Altcode:
  In the 2010 horizon, solar space missions such as LYOT and Solar
  Orbiter will allow high cadence UV observations of the Sun at spatial
  and spectral resolution never obtained before. To reach these goals,
  the two missions could take advantage of spectro-imagers. A reflective
  only optical solution for such an instrument is described in this
  paper and the first results of the mock-up being built at IAS are shown.

Title: Definition of a metrology servo-system for a solar imaging
    fourier transform spectrometer working in the far UV (IFTSUV)
Authors: Ruiz de Galarreta Fanju, C.; Philippon, A.; Bouzit, M.;
   Appourchaux, T.; Vial, J. -C.; Maillard, J. -P.; Lemaire, P.
Bibcode: 2017SPIE10564E..3ER
Altcode:
  The understanding of the solar outer atmosphere requires a simultaneous
  combination of imaging and spectral observations concerning the far UV
  lines that arise from the high chromospheres up to the corona. These
  observations must be performed with enough spectral, spatial and
  temporal resolution to reveal the small atmospheric structures and to
  resolve the solar dynamics. An Imaging Fourier Transform Spectrometer
  working in the far-UV (IFTSUV, Figure 1) is an attractive instrumental
  solution to fulfill these requirements. However, due to the short
  wavelength, to preserve IFTSUV spectral precision and Signal to Noise
  Ratio (SNR) requires a high optical surface quality and a very accurate
  (linear and angular) metrology to maintain the optical path difference
  (OPD) during the entire scanning process by: optical path difference
  sampling trigger; and dynamic alignment for tip/tilt compensation
  (Figure 2).

Title: The Fate of Cool Material in the Hot Corona: Solar Prominences
    and Coronal Rain
Authors: Liu, Wei; Antolin, Patrick; Sun, Xudong; Vial, Jean-Claude;
   Berger, Thomas
Bibcode: 2017SPD....4810501L
Altcode:
  As an important chain of the chromosphere-corona mass cycle,
  some of the million-degree hot coronal mass undergoes a radiative
  cooling instability and condenses into material at chromospheric or
  transition-region temperatures in two distinct forms - prominences
  and coronal rain (some of which eventually falls back to the
  chromosphere). A quiescent prominence usually consists of numerous
  long-lasting, filamentary downflow threads, while coronal rain consists
  of transient mass blobs falling at comparably higher speeds along
  well-defined paths. It remains puzzling why such material of similar
  temperatures exhibit contrasting morphologies and behaviors. We report
  recent SDO/AIA and IRIS observations that suggest different magnetic
  environments being responsible for such distinctions. Specifically,
  in a hybrid prominence-coronal rain complex structure, we found that
  the prominence material is formed and resides near magnetic null points
  that favor the radiative cooling process and provide possibly a high
  plasma-beta environment suitable for the existence of meandering
  prominence threads. As the cool material descends, it turns into
  coronal rain tied onto low-lying coronal loops in a likely low-beta
  environment. Such structures resemble to certain extent the so-called
  coronal spiders or cloud prominences, but the observations reported
  here provide critical new insights. We will discuss the broad physical
  implications of these observations for fundamental questions, such as
  coronal heating and beyond (e.g., in astrophysical and/or laboratory
  plasma environments).

Title: Neutral Hydrogen and Its Emission Lines in the Solar Corona
Authors: Vial, Jean-Claude; Chane-Yook, Martine
Bibcode: 2016SoPh..291.3549V
Altcode: 2016SoPh..tmp..184V; 2016arXiv160905092V
  Since the Lyman-α rocket observations of Gabriel (Solar Phys.21,
  392, 1971), it has been realized that the hydrogen (H) lines could be
  observed in the corona and that they offer an interesting diagnostic
  for the temperature, density, and radial velocity of the coronal
  plasma. Moreover, various space missions have been proposed to measure
  the coronal magnetic and velocity fields through polarimetry in H
  lines. A necessary condition for such measurements is to benefit from a
  sufficient signal-to-noise ratio. The aim of this article is to evaluate
  the emission in three representative lines of H for three different
  coronal structures. The computations have been performed with a full
  non-local thermodynamic-equilibrium (non-LTE) code and its simplified
  version without radiative transfer. Since all collisional and radiative
  quantities (including incident ionizing and exciting radiation) are
  taken into account, the ionization is treated exactly. Profiles are
  presented at two heights (1.05 and 1.9 solar radii, from Sun center)
  in the corona, and the integrated intensities are computed at heights up
  to five solar radii. We compare our results with previous computations
  and observations (e.g. Lα from Ultraviolet Coronal Spectrometer)
  and find a rough (model-dependent) agreement. Since the Hα line is a
  possible candidate for ground-based polarimetry, we show that in order
  to detect its emission in various coronal structures, it is necessary
  to use a very narrow (less than 2 Å wide) bandpass filter.

Title: From the Observation of Non-symmetrical Profiles of the C IV
    Resonance Lines for Small Dynamic Events to their Interpretation in
    Terms of Resonant Scattering in Solar Active Regions
Authors: Vial, J. C.
Bibcode: 2016AGUFMSH33A..01V
Altcode:
  We present observations of small areas in solar active regions recorded
  with the SUMER/SOHO spectrograph where the C IV 1548A and 1550A lines
  have spectral profiles of different shapes, although they are recorded
  simultaneously and at the same location. We propose to explain this
  asymmetry by resonant scattering of strong incident radiation from
  close-by regions, associated with relative velocities of the emitting
  plasmas. We present detailed artificial spectral profiles that may
  explain the observations. The profiles have been computed using several
  physical parameters such as the plasma temperature and electron density
  and the incident radiation on the emitting volumes. We conclude that
  the study of asymmetries in the C IV 1548A, 1550A lines, and also in
  different doublets (e.g. Si IV for IRIS), should include this radiative
  interaction and moreover that it can be a valuable diagnostic tool for
  deriving the physical conditions in solar/stellar plasmas, especially
  where the radiation processes (such as flare-emission) are enhanced
  at the vicinity of the observed structures.

Title: Probing the Physical Connection between Solar Prominences
    and Coronal Rain
Authors: Liu, W.; Antolin, P.; Sun, X.; Vial, J. C.; Guo, L.; Gibson,
   S. E.; Berger, T. E.; Okamoto, J.; De Pontieu, B.
Bibcode: 2016AGUFMSH43C2587L
Altcode:
  Solar prominences and coronal rain are intimately related phenomena,
  both involving cool material at chromospheric temperatures within the
  hot corona and both playing important roles as part of the return flow
  of the chromosphere-corona mass cycle. At the same time, they exhibit
  distinct morphologies and dynamics not yet well understood. Quiescent
  prominences consist of numerous long-lasting, filamentary downflow
  threads, while coronal rain is more transient and falls comparably
  faster along well-defined curved paths. We report here a novel, hybrid
  prominence-coronal rain complex in an arcade-fan geometry observed
  by SDO/AIA and IRIS, which provides new insights to the underlying
  physics of such contrasting behaviors. We found that the supra-arcade
  fan region hosts a prominence sheet consisting of meandering threads
  with broad line widths. As the prominence material descends to the
  arcade, it turns into coronal rain sliding down coronal loops with
  line widths 2-3 times narrower. This contrast suggests that distinct
  local plasma and magnetic conditions determine the fate of the cool
  material, a scenario supported by our magnetic field extrapolations
  from SDO/HMI. Specifically, the supra-arcade fan (similar to those
  in solar flares) is likely situated in a current sheet, where the
  magnetic field is weak and the plasma-beta could be close to unity, thus
  favoring turbulent flows like those prominence threads. In contrast,
  the underlying arcade has a stronger magnetic field and most likely a
  low-beta environment, such that the material is guided along magnetic
  field lines to appear as coronal rain. We will discuss the physical
  implications of these observations beyond the phenomena of prominences
  and coronal rain.

Title: Where are we with the Pending Issues of Prominence Formation,
    Lifetime and Eruption?
Authors: Vial, J. C.
Bibcode: 2016AGUFMSH41E..02V
Altcode:
  As shown by most recent reviews (e.g. Solar Prominences, 2015, ASSL
  415), the formation, existence (and eruption) of solar prominences are
  still a mystery. There are many reasons for that : their complexity
  in terms of geometry and fine structure, the crucial rôle of the
  magnetic field (and its difficult measurement), the mixed nature of the
  plasma (neither neutral nor fully ionized), the rôle of the powerful
  photospheric, chromospheric and coronal incident radiation in the energy
  budget, etc ... We propose to have a review of the latest discoveries
  in the field resulting from the most recent missions (such as IRIS)
  and ground-based instrumentation along with NLTE and MHD modelling. We
  will also address some significant results on the connection between
  Eruptive Prominences and CMEs.

Title: Joint SDO and IRIS Observations of a Novel, Hybrid
    Prominence-Coronal Rain Complex
Authors: Liu, Wei; Antolin, Patrick; Sun, Xudong; Gao, Lijia; Vial,
   Jean-Claude; Gibson, Sarah; Okamoto, Takenori; Berger, Thomas;
   Uitenbroek, Han; De Pontieu, Bart
Bibcode: 2016usc..confE..99L
Altcode:
  Solar prominences and coronal rain are intimately related phenomena,
  both involving cool material at chromospheric temperatures within the
  hot corona and both playing important roles as part of the return flow
  of the chromosphere-corona mass cycle. At the same time, they exhibit
  distinct morphologies and dynamics not yet well understood. Quiescent
  prominences consist of numerous long-lasting, filamentary downflow
  threads, while coronal rain is more transient and falls comparably
  faster along well-defined curved paths. We report here a novel, hybrid
  prominence-coronal rain complex in an arcade-fan geometry observed
  by SDO/AIA and IRIS, which provides new insights to the underlying
  physics of such contrasting behaviors. We found that the supra-arcade
  fan region hosts a prominence sheet consisting of meandering threads
  with broad line widths. As the prominence material descends to the
  arcade, it turns into coronal rain sliding down coronal loops with
  line widths 2-3 times narrower. This contrast suggests that distinct
  local plasma and magnetic conditions determine the fate of the cool
  material, a scenario supported by our magnetic field extrapolations
  from SDO/HMI. Specifically, the supra-arcade fan (similar to those
  in solar flares; e.g., McKenzie 2013) is likely situated in a current
  sheet, where the magnetic field is weak and the plasma-beta could be
  close to unity, thus favoring turbulent flows like those prominence
  threads. In contrast, the underlying arcade has a stronger magnetic
  field and most likely a low-beta environment, such that the material
  is guided along magnetic field lines to appear as coronal rain. We
  will discuss the physical implications of these observations beyond
  prominence and coronal rain.

Title: Automated detection, characterization, and tracking of
    filaments from SDO data
Authors: Buchlin, E.; Mercier, C.; Vial, J. -C.
Bibcode: 2016usc..confE.100B
Altcode:
  Thanks to the cadence and continuity of AIA and HMI observations, SDO
  offers unique data for detecting, characterizing, and tracking solar
  filaments, until their eruptions, which are often associated with
  coronal mass ejections. Because of the requirement of short latency
  when aiming at space weather applications, and because of the important
  data volume, only an automated detection can be worked out. We present
  the code "FILaments, Eruptions, and Activations detected from Space"
  (FILEAS) that we have developed for the automated detection and
  tracking of filaments. Detections are based on the analysis of AIA
  30.4 nm He II images and on the magnetic polarity inversion lines
  derived from HMI. Following the tracking of filaments as they rotate
  with the Sun, filament characteristics are computed and a database of
  filaments parameters is built. We are currently building a database
  of filament detections by this code, covering the full SDO mission,
  and that will be made available to the community.

Title: A small mission concept to the Sun-Earth Lagrangian L5 point
    for innovative solar, heliospheric and space weather science
Authors: Lavraud, B.; Liu, Y.; Segura, K.; He, J.; Qin, G.; Temmer,
   M.; Vial, J. -C.; Xiong, M.; Davies, J. A.; Rouillard, A. P.; Pinto,
   R.; Auchère, F.; Harrison, R. A.; Eyles, C.; Gan, W.; Lamy, P.;
   Xia, L.; Eastwood, J. P.; Kong, L.; Wang, J.; Wimmer-Schweingruber,
   R. F.; Zhang, S.; Zong, Q.; Soucek, J.; An, J.; Prech, L.; Zhang,
   A.; Rochus, P.; Bothmer, V.; Janvier, M.; Maksimovic, M.; Escoubet,
   C. P.; Kilpua, E. K. J.; Tappin, J.; Vainio, R.; Poedts, S.; Dunlop,
   M. W.; Savani, N.; Gopalswamy, N.; Bale, S. D.; Li, G.; Howard, T.;
   DeForest, C.; Webb, D.; Lugaz, N.; Fuselier, S. A.; Dalmasse, K.;
   Tallineau, J.; Vranken, D.; Fernández, J. G.
Bibcode: 2016JASTP.146..171L
Altcode:
  We present a concept for a small mission to the Sun-Earth Lagrangian L5
  point for innovative solar, heliospheric and space weather science. The
  proposed INvestigation of Solar-Terrestrial Activity aNd Transients
  (INSTANT) mission is designed to identify how solar coronal magnetic
  fields drive eruptions, mass transport and particle acceleration that
  impact the Earth and the heliosphere. INSTANT is the first mission
  designed to (1) obtain measurements of coronal magnetic fields from
  space and (2) determine coronal mass ejection (CME) kinematics with
  unparalleled accuracy. Thanks to innovative instrumentation at a vantage
  point that provides the most suitable perspective view of the Sun-Earth
  system, INSTANT would uniquely track the whole chain of fundamental
  processes driving space weather at Earth. We present the science
  requirements, payload and mission profile that fulfill ambitious science
  objectives within small mission programmatic boundary conditions.

Title: The SPICE Spectral Imager on Solar Orbiter: Linking the Sun
    to the Heliosphere
Authors: Fludra, Andrzej; Haberreiter, Margit; Peter, Hardi; Vial,
   Jean-Claude; Harrison, Richard; Parenti, Susanna; Innes, Davina;
   Schmutz, Werner; Buchlin, Eric; Chamberlin, Phillip; Thompson,
   William; Gabriel, Alan; Morris, Nigel; Caldwell, Martin; Auchere,
   Frederic; Curdt, Werner; Teriaca, Luca; Hassler, Donald M.; DeForest,
   Craig; Hansteen, Viggo; Carlsson, Mats; Philippon, Anne; Janvier, Miho;
   Wimmer-Schweingruber, Robert; Griffin, Douglas; Davila, Joseph; Giunta,
   Alessandra; Waltham, Nick; Eccleston, Paul; Gottwald, Alexander;
   Klein, Roman; Hanley, John; Walls, Buddy; Howe, Chris; Schuehle, Udo
Bibcode: 2016cosp...41E.607F
Altcode:
  The SPICE (Spectral Imaging of the Coronal Environment) instrument is
  one of the key remote sensing instruments onboard the upcoming Solar
  Orbiter Mission. SPICE has been designed to contribute to the science
  goals of the mission by investigating the source regions of outflows
  and ejection processes which link the solar surface and corona to the
  heliosphere. In particular, SPICE will provide quantitative information
  on the physical state and composition of the solar atmosphere
  plasma. For example, SPICE will access relative abundances of ions to
  study the origin and the spatial/temporal variations of the 'First
  Ionization Potential effect', which are key signatures to trace the
  solar wind and plasma ejections paths within the heliosphere. Here we
  will present the instrument and its performance capability to attain the
  scientific requirements. We will also discuss how different observation
  modes can be chosen to obtain the best science results during the
  different orbits of the mission. To maximize the scientific return of
  the instrument, the SPICE team is working to optimize the instrument
  operations, and to facilitate the data access and their exploitation.

Title: The potential of hydrogen lines for the spectropolarimetry
    of the solar corona
Authors: Vial, Jean-Claude; Chane-Yook, Martine
Bibcode: 2016cosp...41E2003V
Altcode:
  Neutral Hydrogen lines have been detected in the hot and ionized
  solar corona as early as 1970 (Gabriel et al. 1971) and since then
  with the Spartan and UVCS/SoHO space experiments. Moreover, because
  of the sensitivity of the Lyman lines to the Hanle effect (Bommier
  and Sahal-Brechot 1982, Trujillo Bueno et al. 2005), polarization
  measurements in these lines could lead to the diagnostic of weak
  magnetic fields in the corona (Derouich et al. 2010), a challenge
  which has led to various space mission proposals such as LYOT/SMESE
  or MASC. Our investigation concerns the computation of the emission
  in 10 selected lines of Hydrogen (Lyman, Balmer, and Paschen) taking
  into account the proper computation of the NonLTE H ionization and
  atomic levels populations. We present the results for three different
  coronal models (streamer, quiet Sun and coronal hole) in terms of
  profiles and absolute intensities at altitudes varying from 1.05 to
  1.9 solar radius. These spectrophotometric results could help for the
  determination of the space and ground-based polarimetric instrumentation
  best suited for the measurement of the coronal magnetic field.

Title: Solar abundances with the SPICE spectral imager on Solar
    Orbiter
Authors: Giunta, Alessandra; Haberreiter, Margit; Peter, Hardi;
   Vial, Jean-Claude; Harrison, Richard; Parenti, Susanna; Innes, Davina;
   Schmutz, Werner; Buchlin, Eric; Chamberlin, Phillip; Thompson, William;
   Bocchialini, Karine; Gabriel, Alan; Morris, Nigel; Caldwell, Martin;
   Auchere, Frederic; Curdt, Werner; Teriaca, Luca; Hassler, Donald M.;
   DeForest, Craig; Hansteen, Viggo; Carlsson, Mats; Philippon, Anne;
   Janvier, Miho; Wimmer-Schweingruber, Robert; Griffin, Douglas; Baudin,
   Frederic; Davila, Joseph; Fludra, Andrzej; Waltham, Nick; Eccleston,
   Paul; Gottwald, Alexander; Klein, Roman; Hanley, John; Walls, Buddy;
   Howe, Chris; Schuehle, Udo; Gyo, Manfred; Pfiffner, Dany
Bibcode: 2016cosp...41E.681G
Altcode:
  Elemental composition of the solar atmosphere and in particular
  abundance bias of low and high First Ionization Potential (FIP)
  elements are a key tracer of the source regions of the solar wind. These
  abundances and their spatio-temporal variations, as well as the other
  plasma parameters , will be derived by the SPICE (Spectral Imaging
  of the Coronal Environment) EUV spectral imager on the upcoming
  Solar Orbiter mission. SPICE is designed to provide spectroheliograms
  (spectral images) using a core set of emission lines arising from ions
  of both low-FIP and high-FIP elements. These lines are formed over
  a wide range of temperatures, enabling the analysis of the different
  layers of the solar atmosphere. SPICE will use these spectroheliograms
  to produce dynamic composition maps of the solar atmosphere to be
  compared to in-situ measurements of the solar wind composition of
  the same elements (i.e. O, Ne, Mg, Fe). This will provide a tool to
  study the connectivity between the spacecraft (the Heliosphere) and
  the Sun. We will discuss the SPICE capabilities for such composition
  measurements.

Title: Automated detection, characterization, and tracking of
    filaments from SDO data
Authors: Buchlin, Eric; Vial, Jean-Claude; Mercier, Claude
Bibcode: 2016cosp...41E.258B
Altcode:
  Thanks to the cadence and continuity of AIA and HMI observations, SDO
  offers unique data for detecting, characterizing, and tracking solar
  filaments, until their eruptions, which are often associated with
  coronal mass ejections. Because of the requirement of short latency
  when aiming at space weather applications, and because of the important
  data volume, only an automated detection can be worked out. We present
  the code "FILaments, Eruptions, and Activations detected from Space"
  (FILEAS) that we have developed for the automated detection and tracking
  of filaments. Detections are based on the analysis of AIA 30.4 nm He
  II images and on the magnetic polarity inversion lines derived from
  HMI. Following the tracking of filaments as they rotate with the Sun,
  filament characteristics are computed and a database of filaments
  parameters is built. We present the algorithms and performances of the
  code, and we compare its results with the filaments detected in Hα and
  already present in the Heliophysics Events Knowledgebase. We finally
  discuss the possibility of using such a code to detect eruptions in
  real time.

Title: Non-symmetrical profiles of the C IV 1548A and 1550A lines for
    small dynamic events and their interpretation in terms of resonant
    scattering in solar active region
Authors: Gontikakis, Costis; Vial, Jean-Claude
Bibcode: 2016cosp...41E.702G
Altcode:
  We present observations of small areas in solar active regions
  recorded with the SUMER/SOHO spectrograph where the C IV 1548A and
  1550A lines have spectral profiles of different shapes, although they
  are recorded simultaneously and at the same location. This asymmetry
  may be explained by resonant scattering associated with relative
  velocities of the emitting plasmas. We present detailed artificial
  spectral profiles that may explain the observations. The profiles have
  been computed using several physical parameters such as the plasma
  temperature and electron density and/or the incident radiation on
  the emitting volumes. We conclude that the study of asymmetries in
  the C IV 1548A, 1550A lines, and also in different doublets, can be
  a valuable diagnostic tool for deriving the physical conditions in
  solar/stellar plasmas, especially where the radiation processes (such as
  flare-emission) are enhanced at the vicinity of the observed structures.

Title: Evidence of scattering effects influenced by plasma flows in
    C VI 1548 Å, 1550 Å spectral lines emitted from the Sun
Authors: Gontikakis, C.; Vial, J. -C.
Bibcode: 2016A&A...590A..86G
Altcode:
  <BR /> Aims: We search for, and study, individual spectral profiles
  where the complex shape of the C iv 1548 Å line is different from
  the shape of the simultaneously recorded C iv 1550 Å line. Such an
  asymmetry is not expected for line emission resulting from collisional
  excitation. Therefore we propose an explanation of these observations
  through the differential effect of velocity fields on resonant
  scattering. <BR /> Methods: We analyse spectra recorded with the Solar
  Ultraviolet Measurements of Emitted Radiation (SUMER) on the Solar and
  Heliospheric Observatory (SOHO) over active region, NOAA 8541 as well
  as a second data set on the quiet Sun. We perform Gaussian fits on the
  individual profiles with two or three Gaussian functions. Moreover,
  we parameterize the profile asymmetries by calculating the intensity
  ratios I<SUB>1548</SUB>/I<SUB>1550</SUB>, from the derived Gaussian
  functions. We also calculate artificial spectral profiles emitted from
  two plasma volumes, which have different line of sight motions and
  where the plasma emission is influenced by resonant scattering. <BR />
  Results: We locate three small regions in NOAA 8541 which have spectral
  asymmetries. There the profiles have two or three spectral components,
  with different intensity ratios. Artificial profiles show that two
  plasma volumes, having distinct velocities relative to the observer,
  may reproduce the observed profiles, under the influence of resonant
  scattering. <BR /> Conclusions: Asymmetric profiles, found in an active
  region, can be used as a diagnostic for the importance of resonant
  scattering in transition region plasma.

Title: Observed IRIS Profiles of the h and k Doublet of Mg II and
    Comparison with Profiles from Quiescent Prominence NLTE Models
Authors: Vial, Jean-Claude; Pelouze, Gabriel; Heinzel, Petr; Kleint,
   Lucia; Anzer, Ulrich
Bibcode: 2016SoPh..291...67V
Altcode: 2015SoPh..tmp..173V
  With the launch of the Interface Region Imaging Spectrograph (IRIS)
  mission, it is now possible to obtain high-resolution solar prominence
  spectra and to begin to distinguish the contributions of the many
  (apparent or not) threads that structure prominences. We aim at
  comparing unique observations obtained in the Mg II h and k lines of a
  polar crown prominence with the radiative outputs from one-dimensional
  models built with non-local-thermodynamic equilibrium codes (Heinzel et
  al.Astron. Astrophys.564, A132, 2014). We characterize the profiles
  obtained through thorough calibration procedures, with attention
  paid to the absolute values, full-width at half-maximum, and the
  ratio of k to h intensities. We also show that at the top of some
  structures, line-of-sight velocities of about 9 kms−<SUP>1</SUP> can
  be detected. We find a range of static, low-pressure, low-thickness,
  low-temperature models that could fit k or h observed values, but that
  cannot satisfy the low observed k/h ratio. We investigate whether these
  low values might be explained by the inclusion of horizontal flows in
  small-scale threads. These flows are also necessary in another class
  of models, where the pressure is kept low but thickness and temperature
  are increased up to the observed thickness and up to 15 000 K.

Title: Hydrogen Ly-α and Ly-β full Sun line profiles observed with
    SUMER/SOHO (1996-2009)
Authors: Lemaire, P.; Vial, J. -C.; Curdt, W.; Schühle, U.;
   Wilhelm, K.
Bibcode: 2015A&A...581A..26L
Altcode:
  Context. Accurate hydrogen spectra emitted by the entire solar disc in
  the Ly-α and Ly-βlines are valuable for deriving the distribution and
  the behaviour of atomic hydrogen in the heliosphere, for understanding
  the UV emissions of solar type stars better, and finally for estimating
  the solar energy input that mainly initiates the chemical processes
  occurring in the planetary and cometary outer atmospheres. <BR /> Aims:
  In this paper we want to accurately determine the irradiance solar
  spectral profiles of Ly-α and Ly-β and their evolution through the
  solar activity cycle 23. <BR /> Methods: The SUMER/SOHO spectrometer is
  a slit spectrometer that is only able to analyse a small part of the
  solar image. Consequently, we used the scattered light properties of
  the telescope to obtain average spectra over the solar disc. Then the
  profile is calibrated using the SOLSTICE/UARS and TIMED/SEE irradiance
  spectra. <BR /> Results: We obtained a set of irradiance Ly-α and
  Ly-β solar spectra with a 0.002 nm resolution through the solar
  activity cycle 23. In each line a relation between the integrated
  profile and the line centre intensity was obtained.Knowing the line
  irradiance, it is possible to deduce the central line profile intensity,
  a critical input into the interplanetary and planetary oxygen and
  hydrogen fluorescent processes. <BR /> Conclusions: The observation
  of H i Ly-α and Ly-β line profiles by SUMER/SOHO during the cycle
  23 allows analysis of the evolution of their characteristics and
  accurate determination of UV radiation input into the solar system. <P
  />Profiles are only available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/581/A26">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/581/A26</A>

Title: VizieR Online Data Catalog: Sun hydrogen Lyman irradiance
    lines profiles (Lemaire+, 2015)
Authors: Lemaire, P.; Vial, J. -C.; Curdt, W.; Schuhle, U.; Wilhelm, K.
Bibcode: 2015yCat..35810026L
Altcode:
  Set of irradiance Ly-α and Ly-β solar spectra with a 0.002nm
  resolution through the solar activity cycle 23. The wavelength distance
  from line center is given every 0.001nm. <P />(2 data files).

Title: First High-resolution Spectroscopic Observations of an Erupting
    Prominence Within a Coronal Mass Ejection by the Interface Region
    Imaging Spectrograph (IRIS)
Authors: Liu, Wei; De Pontieu, Bart; Vial, Jean-Claude; Title, Alan
   M.; Carlsson, Mats; Uitenbroek, Han; Okamoto, Takenori J.; Berger,
   Thomas E.; Antolin, Patrick
Bibcode: 2015ApJ...803...85L
Altcode: 2015arXiv150204738L
  Spectroscopic observations of prominence eruptions associated with
  coronal mass ejections (CMEs), although relatively rare, can provide
  valuable plasma and three-dimensional geometry diagnostics. We report
  the first observations by the Interface Region Imaging Spectrograph
  mission of a spectacular fast CME/prominence eruption associated with
  an equivalent X1.6 flare on 2014 May 9. The maximum plane-of-sky and
  Doppler velocities of the eruption are 1200 and 460 km s<SUP>-1</SUP>,
  respectively. There are two eruption components separated by ∼200
  km s<SUP>-1</SUP> in Doppler velocity: a primary, bright component
  and a secondary, faint component, suggesting a hollow, rather than
  solid, cone-shaped distribution of material. The eruption involves
  a left-handed helical structure undergoing counterclockwise (viewed
  top-down) unwinding motion. There is a temporal evolution from upward
  eruption to downward fallback with less-than-free-fall speeds and
  decreasing nonthermal line widths. We find a wide range of Mg ii k/h
  line intensity ratios (less than ∼2 expected for optically-thin
  thermal emission): the lowest ever reported median value of 1.17
  found in the fallback material, a comparably high value of 1.63 in
  nearby coronal rain, and intermediate values of 1.53 and 1.41 in
  the two eruption components. The fallback material exhibits a strong
  (\gt 5σ ) linear correlation between the k/h ratio and the Doppler
  velocity as well as the line intensity. We demonstrate that Doppler
  dimming of scattered chromospheric emission by the erupted material
  can potentially explain such characteristics.

Title: The Balmer Lines of He II in the Blue Wing of the Hydrogen
    Lyman α Line Observed in a Quiescent Prominence
Authors: Vial, J. -C.; Eurin, G.; Curdt, W.
Bibcode: 2015SoPh..290..381V
Altcode:
  We revisit the prominence observations in the Lyman α line of Curdt
  et al. (Astron. Astrophys.511, L4, 2010) and focus on the bump in the
  blue wing of the line, which we identify with He II Balmer lines. We
  determine the transition candidates, derive an upper limit for the
  width of the profile and an associated non-thermal velocity close to 0
  km s<SUP>−1</SUP>, with the assumption that the kinetic temperature
  is equal to the formation temperature. We compare the total intensity
  with the corresponding H Lyman α intensity and find a ratio much
  lower than that measured by Ebadi, Vial, and Ajabshirizadeh (Solar
  Phys.257, 91, 2009) in other Lyman lines. We confirm this result with
  observations performed by Schwartz et al. (private communication,
  2014), we discuss a possible interpretation, and suggest that this
  issue needs to be addressed closely in future observations.

Title: Solar Prominences
Authors: Vial, Jean-Claude; Engvold, Oddbjørn
Bibcode: 2015ASSL..415.....V
Altcode:
  No abstract at ADS

Title: Historical Background and Introduction
Authors: Vial, Jean-Claude
Bibcode: 2015ASSL..415....1V
Altcode:
  Forty and twenty years after the two books published by Einar
  Tandberg-Hanssen (Solar prominences (Geophysics and astrophysics
  monographs), Vol. 12. Dordrecht: D. Reidel Publishing Co., 1974; The
  nature of solar prominences, astrophysics and space science library,
  Vol. 199. Dordrecht: Kluwer Academic Publishers, 1995) on solar
  prominences, it is time to update our knowledge and understanding
  of these fascinating solar structures. After a brief history which
  overviews first eclipse observations (drawings and then photography),
  spectrographic, coronagraphic and later on polarimetric measurements,
  the chapter presents samples of the most spectacular results of the last
  two decades, obtained whether from space or on the ground. It discusses
  the contents of the book in order to encourage the reader to dip into
  the following 17 chapters which provide comprehensive and detailed
  observations, information about the methods used, and interpretation of
  the results on the basis of the latest theoretical and modelling works.

Title: Instant: An Innovative L5 Small Mission Concept for Coordinated
    Science with Solar Orbiter and Solar Probe Plus
Authors: Lavraud, B.; Liu, Y. D.; Harrison, R. A.; Liu, W.;
   Auchere, F.; Gan, W.; Lamy, P. L.; Xia, L.; Eastwood, J. P.;
   Wimmer-Schweingruber, R. F.; Zong, Q.; Rochus, P.; Maksimovic, M.;
   Temmer, M.; Escoubet, C. P.; Kilpua, E.; Rouillard, A. P.; Davies,
   J. A.; Vial, J. C.; Gopalswamy, N.; Bale, S. D.; Li, G.; Howard,
   T. A.; DeForest, C. E.
Bibcode: 2014AGUFMSH21B4109L
Altcode:
  We will present both the science objectives and related instrumentation
  of a small solar and heliospheric mission concept, INSTANT:
  INvestigation of Solar-Terrestrial Activity aNd Transients. It will be
  submitted as an opportunity to the upcoming ESA-China S-class mission
  call later this year. This concept was conceived to allow innovative
  measurements and unprecedented, early determination of key properties
  of Earthbound CMEs from the L5 vantage point. Innovative measurements
  will include magnetic field determination in the corona thanks to
  Hanle measurement in Lyman-α and polarized heliospheric imaging
  for accurate determination of CME trajectories. With complementary
  in situ measurements, it will uniquely permit solar storm science,
  solar storm surveillance, and synergy with Solar Orbiter and Solar
  Probe Plus (the ESA-China S2 mission launch is planned in 2021).

Title: First High-resolution Spectroscopic Observations by IRIS
    of a Fast, Helical Prominence Eruption Associated with a Coronal
    Mass Ejection
Authors: Liu, W.; De Pontieu, B.; Okamoto, T. J.; Vial, J. C.; Title,
   A. M.; Antolin, P.; Berger, T. E.; Uitenbroek, H.
Bibcode: 2014AGUFMSH11D..04L
Altcode:
  High-resolution spectroscopic observations of prominence eruptions and
  associated coronal mass ejections (CMEs) are rare but can provide
  valuable plasma and energy diagnostics. New opportunities have
  recently become available with the advent of the Interface Region
  Imaging Spectrograph (IRIS) mission equipped with high resolution of
  0.33-0.4 arcsec in space and 1 km/s in velocity, together with the
  Hinode Solar Optical Telescope of 0.2 arcsec spatial resolution. We
  report the first result of joint IRIS-Hinode observations of a
  spectacular prominence eruption occurring on 2014-May-09. IRIS
  detected a maximum redshift of 450 km/s, which, combined with the
  plane-of-sky speed of 800 km/s, gives a large velocity vector of 920
  km/s at 30 degrees from the sky plane. This direction agrees with the
  source location at 30 degrees behind the limb observed by STEREO-A
  and indicates a nearly vertical ejection. We found two branches of
  redshifts separated by 200 km/s appearing in all strong lines at
  chromospheric to transition-region temperatures, including Mg II k/h,
  C II, and Si IV, suggesting a hollow, rather than solid, cone in the
  velocity space of the ejected material. Opposite blue- and redshifts
  on the two sides of the prominence exhibit corkscrew variations both
  in space and time, suggestive of unwinding rotations of a left-handed
  helical flux rope. Some erupted material returns as nearly streamline
  flows, exhibiting distinctly narrow line widths (~10 km/s), about
  50% of those of the nearby coronal rain at the apexes of coronal
  loops, where the rain material is initially formed out of cooling
  condensation. We estimate the mass and kinetic energy of the ejected
  and returning material and compare them with those of the associated
  CME. We will discuss the implications of these observations for CME
  initiation mechanisms.

Title: On the formation of Mg ii h and k lines in solar prominences
Authors: Heinzel, P.; Vial, J. -C.; Anzer, U.
Bibcode: 2014A&A...564A.132H
Altcode:
  <BR /> Aims: With the recent launch of the IRIS mission, it has become
  urgent to develop the spectral diagnostics using the Mg ii resonance
  h and k lines. In this paper, we aim to demonstrate the behavior of
  these lines under various prominence conditions. Our results serve
  as a basis for analysis of new IRIS data and for more sophisticated
  prominence modeling. <BR /> Methods: For this exploratory work,
  we use a canonical 1D prominence-slab model, which is isobaric
  and may have three different temperature structures: isothermal,
  PCTR-like (prominence-corona transition region), and consistent with
  the radiative equilibrium. The slabs are illuminated by a realistic
  incident solar radiation obtained from the UV observations. A five-level
  plus continuum Mg ii model atom is used to solve the full NLTE problem
  of the radiative transfer. We use the numerical code based on the ALI
  techniques and apply the partial frequency redistribution for both
  Mg ii resonance lines. We also use the velocity-dependent boundary
  conditions to study the effect of Doppler dimming in the case of
  moving prominences. Finally, the relaxation technique is used to
  compute a grid of models in radiative equilibrium. <BR /> Results:
  We computed the Mg ii h and k line profiles that are emergent from
  prominence-slab models and show their dependence on kinetic temperature,
  gas pressure, geometrical extension, and microturbulent velocity. By
  increasing the line opacity, significant departures from the complete
  frequency redistribution take place in the line wings. Models with a
  PCTR temperature structure show that Mg ii becomes ionized to Mg iii
  in the temperature range between roughly 15 000 and 30 000 K. Doppler
  dimming is significant for Mg ii resonance lines. At the velocity 300
  km s<SUP>-1</SUP>, the line intensity decreases to about 20% of the
  value for static prominences. Finally, we demonstrate the role of Mg
  ii h and k radiation losses on the prominence energy balance. Their
  dominant role is at lower pressures, while the losses due to hydrogen
  and Ca ii dominate at higher pressures.

Title: A comparison between observed IRIS profiles of the h &amp;
    k doublet of Mg II and profiles from quiescent prominence NLTE models
Authors: Vial, Jean-Claude; Anzer, Ulrich; Heinzel, Petr; Kleint, Lucia
Bibcode: 2014cosp...40E3515V
Altcode:
  With the advent of IRIS, it is now possible to investigate the cool core
  of prominences through the detailed profiles of the Mg II resonance
  lines with an unprecedented spatial resolution of 0.33 arcsecond. The
  slit-jaw camera also allows to record the temporal evolution of the
  prominence fine structure. We present IRIS observations of quiescent
  prominence profiles that we analyse in terms of reversal (if any),
  width, k/h line ratio, prominence/ quiet Sun line ratio. Comparing these
  parameters with the results of NLTE modelling (see Heinzel et al. 2014),
  we can derive thermodynamic parameters of the cool prominence plasma,
  along with the (line-of-sight) velocities and mass flows.

Title: INSTANT: INvestigation of Solar-Terrestrial Associated
    Natural Threats
Authors: Lavraud, Benoit; Vial, Jean-Claude; Harrison, Richard; Davies,
   Jackie; Escoubet, C. Philippe; Zong, Qiugang; Auchere, Frederic; Liu,
   Ying; Bale, Stuart; Gopalswamy, Nat; Li, Gang; Maksimovic, Milan;
   Liu, William; Rouillard, Alexis
Bibcode: 2014cosp...40E1758L
Altcode:
  The INSTANT mission will tackle both compelling solar and heliospheric
  science objectives and novel space weather capabilities. This is
  allowed by combining innovative and state-of-the-art instrumentation
  at an appropriate off-Sun-Earth line location on an orbit lagging
  the Earth around the Sun, near the L5 Lagrangian point. It is an
  affordable mission that tackles major objectives of the European and
  Chinese communities in terms of space physics and space weather. The
  science objectives are: 1. What is the magnetic field magnitude and
  topology in the corona? 2. How does the magnetic field reconfigure
  itself during CME eruptions? 3. What are the sources and links between
  the slow and fast winds? 4. How do CMEs accelerate and interact in the
  interplanetary medium? The mission will further allow the following
  crucial space weather capabilities: 5. Three-days advance knowledge
  of CIR properties that reach Earth. 6. Twelve hours to 2 days advance
  warning of Earth-directed CMEs. 7. Thanks to Lyman-α observations,
  first-ever capability of determining the magnetic field magnitude and
  orientation of Earth-directed CMEs. The mission will be proposed in
  the context of the upcoming ESA-China S-class call for mission.

Title: MASC: Magnetic Activity of the Solar Corona
Authors: Auchere, Frederic; Fineschi, Silvano; Gan, Weiqun; Peter,
   Hardi; Vial, Jean-Claude; Zhukov, Andrei; Parenti, Susanna; Li, Hui;
   Romoli, Marco
Bibcode: 2014cosp...40E.149A
Altcode:
  We present MASC, an innovative payload designed to explore the magnetic
  activity of the solar corona. It is composed of three complementary
  instruments: a Hard-X-ray spectrometer, a UV / EUV imager, and a Visible
  Light / UV polarimetric coronagraph able to measure the coronal magnetic
  field. The solar corona is structured in magnetically closed and
  open structures from which slow and fast solar winds are respectively
  released. In spite of much progress brought by two decades of almost
  uninterrupted observations from several space missions, the sources and
  acceleration mechanisms of both types are still not understood. This
  continuous expansion of the solar atmosphere is disturbed by sporadic
  but frequent and violent events. Coronal mass ejections (CMEs) are
  large-scale massive eruptions of magnetic structures out of the corona,
  while solar flares trace the sudden heating of coronal plasma and the
  acceleration of electrons and ions to high, sometimes relativistic,
  energies. Both phenomena are most probably driven by instabilities
  of the magnetic field in the corona. The relations between flares
  and CMEs are still not understood in terms of initiation and energy
  partition between large-scale motions, small-scale heating and
  particle acceleration. The initiation is probably related to magnetic
  reconnection which itself results magnetic topological changes due to
  e.g. flux emergence, footpoints motions, etc. Acceleration and heating
  are also strongly coupled since the atmospheric heating is thought to
  result from the impact of accelerated particles. The measurement of
  both physical processes and their outputs is consequently of major
  importance. However, despite its fundamental importance as a driver
  for the physics of the Sun and of the heliosphere, the magnetic field
  of our star’s outer atmosphere remains poorly understood. This
  is due in large part to the fact that the magnetic field is a very
  difficult quantity to measure. Our knowledge of its strength and
  orientation is primarily based on extrapolations from photospheric
  observations, not from direct measurements. These extrapolations
  require strong assumptions on critical but unobserved quantities and
  thus fail to accurately reproduce the complex topologies inferred
  from remote-sensing observations of coronal structures in white
  light, EUV, and X-rays. Direct measurements of the coronal magnetic
  field are also clearly identified by the international heliophysics
  community as a key element susceptible to lead to major breakthroughs
  in the understanding of our star. MASC is thus designed to answer
  the following top-level scientific questions: 1. What is the global
  magnetic field configuration in the corona? 2. What is the role of
  the magnetic field in the triggering of flares and CMEs? 3. What is
  the role of the magnetic field in the acceleration mechanisms of the
  solar winds? 4. What is the energy spectrum and in particular what are
  the highest energies to which charged particles can be accelerated in
  the solar corona? MASC will address these fundamental questions with
  a suite of instruments composed of an X-ray spectrometer, a UV / EUV
  imager, and a coronagraph working in the visible and at Lyman alpha. The
  spectrometer will provide information on the energetics of solar flares,
  in particular at very high energies of accelerated particles. The
  UV / EUV imager will provide constraints on the temperature of the
  flaring and non-flaring corona. The coronagraph will provide the number
  density of free electrons in the corona, maps of the outflow velocity
  of neutral hydrogen, and measurements of the coronal magnetic field,
  via the Hanle effect. These measurements will be performed at all
  steps of the flare-CME processes, thus providing a detailed picture
  of the solar coronal dynamics in the quiet and eruptive periods.

Title: Automated detection, characterization, and tracking of
    filaments from SDO data
Authors: Buchlin, Eric; Vial, Jean-Claude; Mercier, Claude; Goujon,
   Jean-Baptiste
Bibcode: 2014cosp...40E.425B
Altcode:
  Thanks to the cadence and continuity of AIA and HMI observations, SDO
  offers unique data for detecting, characterizing, and tracking solar
  filaments, until their eruptions, which are often associated with
  coronal mass ejections. Because of the requirement of short latency
  when aiming at space weather applications, and because of the important
  data volume, only an automated detection can be worked out. We present
  the code "FILaments, Eruptions, and Activations detected from Space"
  (FILEAS) that we have developed for the automated detection and tracking
  of filaments. Detections are based on the analysis of AIA 30.4 nm He
  II images and on the magnetic polarity inversion lines derived from
  HMI. Following the tracking of filaments as they rotate with the Sun,
  filament characteristics are computed and a database of filaments
  parameters is built. We present the algorithms and performances of
  the code, and we compare its results with the filaments detected in
  Halpha and already present in the Heliophysics Events Knowledgebase. We
  finally discuss the possibility of using such a code to detect eruptions
  in real time.

Title: On the nature of the prominence - corona transition region
Authors: Parenti, Susanna; Vial, Jean-Claude
Bibcode: 2014IAUS..300...69P
Altcode:
  Due to the complexity of their environment, prominences properties are
  still a matter of controversy. Prominences cool and dense plasma is
  suspended in the hot corona by a magnetic structure poorly known. Their
  thermal insulation from the corona results in a thin geometrical
  interface called prominence-corona-transition-region (PCTR). Here we
  will review the main properties of such a region as derived primarily
  from observations. We will introduce the thermal structure properties,
  describe the fine structure together with the Doppler-shift and width
  properties of lines of the emitting plasma. We will introduce the
  proposed interpretations of such observations and the limits of our
  knowledge imposed by the present instrumentation. We will conclude
  with a perspective for the future observations of the PCTR.

Title: The EUV photosphere- corona interface from eclipses to study
    the origin of low- FIP elements and the root of the basis of the
    chromosphere
Authors: Bazin, Cyrille; Veselovsky, Igor; Vial, Jean-Claude; Tavabi,
   Ehsan; Serge, Koutchmy
Bibcode: 2014cosp...40E.236B
Altcode:
  We use the full occultation of the Sun by the Moon to study the upper
  solar atmosphere with flash spectra free of any parasitic light from
  the disc. A radial resolution of 40 km is obtained from unique images
  in many emission lines seen as crescents of the low atmosphere. The
  natural motion of the lunar limb probes the photosphere - corona
  interface where the solar magnetic field emerges. High cadence CCD
  slitless flash spectra obtained before and after the eclipse totality
  (in 2008, 2009, 2010, 2012, and 2013) show that the over-abundance of
  the low First Ionisation Potential elements (low FIP) like FeII, TiII,
  BaII, etc. comes from the interface layers close to the temperature
  minimum. For the 1st time, the solar edge is defined by considering
  the “true” continuum analysed outside of faint emission lines at
  heights ranging from 0.2 to 0.6 Mm. We also measure the helium shells
  of He I 4713Å and of He II 4686Å (Paschen alpha, optically thin high
  FIP lines), starting at the height of 0.8 Mm. Enhancements of the high
  FIP lines (H beta, He I and He II) are found at altitudes lower than
  0.8 Mm above the limb from new 2013 spectra. The extensions of the
  helium shells are compared in equatorial and Polar Regions. The widths
  of the lines are evaluated for the 1st time. The light curves I = f(h)
  corresponding to low FIP ions are measured for different positions of
  the low solar atmosphere. The scale heights correspond to radial density
  gradients allowing temperature evaluations in case of the hydrostatic
  assumptions. We also demonstrate some density gradient analogies
  between the photosphere- corona and the prominence-corona interface
  using the Ti II lines as a marker. The effect of the magnetic field
  emergence for supplying mass to the corona through low FIP elements
  is discussed. A simultaneously obtained 193 SDO/AIA processed image
  is used to discuss what the coronal extensions are.

Title: On the development of a Fourier Transform Spectrometer for
    Solar Physics
Authors: Ruiz de Galarreta, Claudia; Vial, Jean-Claude; Appourchaux,
   Thierry; Philippon, Anne
Bibcode: 2014cosp...40E2793R
Altcode:
  The origin and the evolution of the different structures that inhabit
  beyond the Sun’s photosphere, as well as the processes involved in
  the dynamics and the heating of the corona remain quite unknown. The
  inextricable complexity of the physical phenomena that govern the solar
  outer atmosphere is accompanied by the lack of suitable data adapted to
  the scientific need. Indeed, the interpretation and the models of the
  mechanisms that connect the exchanges between the chromosphere and the
  corona depend on critical observational parameters. It is for example
  essential to measure broad bands of vertical temperature and density
  ranges that fit the multiple spatial and temporal scales that are
  characteristic of the different events that take place in the Sun. The
  understanding of the dynamics of the plasma must be also based on the
  Doppler analysis of the observed scene. That implies the ability to
  combine time resolved spectroscopic and imaging technologies. Moreover,
  space is the place to observe the far UV corona and that implies a
  real technical challenge. Despite excellent advances in technology and
  instrumentation, the study of the Sun in the far UV is a fairly recent
  science. To date, no solar space mission could provide a combined and
  simultaneous diagnostic of both observables in the spectral range of
  interest. It is because of these expectations that the study of a
  new device called IFTSUV (the acronym of Imaging Fourier Transform
  Spectrometer working in the far UV) is presented in this paper. We
  start from the definition of the scientific requirements that lead to
  the technical choice, the first objective of this study is to develop
  a preliminary instrumental model of the IFTSUV. The overall technical
  and design specifications are based in theoretical calculations that
  have been expressed in terms of spectral accuracy, image quality and
  signal to noise ratio. Throughout the identification of difficult
  points, the realization of a servo-metrology system to control the
  sampling mirror appears naturally as an intrinsic need of proof of
  concept. Indeed, the wavenumbers from the raw spectra are set by the
  interferogram. That implies that acquisition must be rigorously constant
  and that the sampling steps must be known with high accuracy. Therefore,
  the mockup of a metrological solution that has been developped at IAS
  will is also presented. The results on the damonstrator that validate
  and converge to the optimization and prototyping of a system that could
  be integrated in a space based application will be discussed. Finally we
  propose a discussion on the possible future space mission opportunities
  in which this innovative project could be framed.

Title: The LYOT+ UV/EUV instrumentation for measuring the magnetic
    field in the corona
Authors: Auchère, Frederic; Vial, Jean Claude
Bibcode: 2013EGUGA..1513788A
Altcode:
  The solar corona is the seat of a variability which involves basic
  processes of plasma-magnetic field interaction in the universe,
  while also being a source of disturbances for spacecraft, technology,
  and possibly for human beings. Of special interest are coronal mass
  ejections (CMEs) with their associated Eruptive Prominences (EPs). Since
  they are basically driven by instabilities of the magnetic field in the
  corona, the measurement of the magnetic field before, after (and during)
  the event is critical in the corona. Also of interest for these studies
  and the source of the solar wind, the radial velocity of the plasma is a
  critical parameter to be determined. We present a new proposal to CNES
  called LYOT+ which meets the above-mentioned objectives: measurement
  of the coronal magnetic field up to 2 solar radii, of the electron
  density and the radial velocity. These measurements are complemented
  by EUV images of the underlying corona providing plasma diagnostic and
  magnetic field morphology. We describe the proposed combination of EUV
  imager and VUV and visible coronagraph. A main feature of the proposed
  instrumentation is the extended overlap of the fields-of-view of both
  instruments. In our presentation, we focus on the polarimetric concept
  which leads to the determination of the magnetic field through the
  Hanle effect. We also mention the extensive studies already performed
  in designing the instrumentation and testing parts of it. In summary,
  science, instrumentation and constraints on missions on which LYOT+
  could be implemented, are presented.

Title: Nature and Variability of Plasmas Ejected by the Sun
Authors: Vial, J. -C.
Bibcode: 2013LNP...857...15V
Altcode:
  The Sun not only emits radiation in the whole electromagnetic spectrum
  but also sends in the interplanetary medium plasmas of different natures
  (energy, continuous, or episodic flows, etc.) which contribute to its
  (small) mass loss. The escaping material when properly oriented may
  impact on the Earth magnetic environment with cascading effects on
  the Earth atmosphere. The continuous flow known as the solar wind is
  actually made of two categories, slow and fast winds. We discuss their
  properties, sources, and the mechanisms at work through the two types
  of models (fluid and particles). We describe the sporadic mass losses
  for the three main typical events: flares, prominence ejection, and
  coronal mass ejection. We discuss a possible unifying scenario which
  takes into account these three manifestations of magnetic disruption. We
  also extend the investigation to the whole heliosphere. Our conclusion
  proposes a few goals concerning the diagnostic and the understanding
  of the plasmas ejected by the Sun, along with the space missions which
  could provide some answers.

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: Metrology for a solar imaging Fourier transform spectrometer
working in the far UV: from the instrumental concept to the first
    experimental results
Authors: Ruiz de Galarreta Fanjul, C.; Bouzit, M.; Appourchaux, T.;
   Dassas, K.; Viale, T.; Philippon, A.; Vial, J. -C.; Maillard, J. -P.
Bibcode: 2012SPIE.8450E..0DR
Altcode:
  The spectroscopy of the far UV emission lines of the solar spectrum
  combined with an imaging capability is essential to understand the
  physics of the outer solar atmosphere. An imaging Fourier transform
  spectrometer (IFTSUV) is an attractive instrumental solution to perform
  such far-UV solar observations. Working in the far UV involves high
  precision metrology to maintain the optical path difference (OPD) during
  the entire scanning process of the interferogram. It also involves
  a compact all-reflection design for UV applications. We present
  the specification of a servo-system that enables dynamic tip/tilt
  alignment compensation and OPD sampling measurement of the IFTSUV
  scanning mirror. We also discuss the first experimental results of a
  breadboard as well as the preliminary design of a space-based device.

Title: Flows in a Small Active Region as Seen by Hinode and SoHO
Authors: Boutry, C.; Buchlin, É.; Vial, J.
Bibcode: 2012ASPC..454..233B
Altcode:
  We report on a multi-instrument study performed on Active Region 10943
  located at Sun center on 20 Feb. 2007. We use XRT images, magnetic
  field maps from SoHO/MDI and we focus on EIS spectra from which we
  build maps of the Doppler shift and intensity of Fe XII 195.12 Å. We
  paid a special attention to the absolute wavelength calibration taking
  into account the orbital temperature effect. We observe coronal loops
  between opposite polarities of the region and straight downflows seen
  in faint regions.

Title: Flows at the Edge of an Active Region: Observation and
    Interpretation
Authors: Boutry, C.; Buchlin, E.; Vial, J. -C.; Régnier, S.
Bibcode: 2012ApJ...752...13B
Altcode: 2012arXiv1204.1377B
  Upflows observed at the edges of active regions have been proposed as
  the source of the slow solar wind. In the particular case of Active
  Region (AR) 10942, where such an upflow has been already observed,
  we want to evaluate the part of this upflow that actually remains
  confined in the magnetic loops that connect AR 10942 to AR 10943. Both
  active regions were visible simultaneously on the solar disk and were
  observed by STEREO/SECCHI EUVI. Using Hinode/EIS spectra, we determine
  the Doppler shifts and densities in AR 10943 and AR 10942 in order to
  evaluate the mass flows. We also perform magnetic field extrapolations
  to assess the connectivity between AR 10942 and AR 10943. AR 10943
  displays a persistent downflow in Fe XII. Magnetic extrapolations
  including both ARs show that this downflow can be connected to the
  upflow in AR 10942. We estimate that the mass flow received by AR 10943
  areas connected to AR 10942 represents about 18% of the mass flow from
  AR 10942. We conclude that the upflows observed on the edge of active
  regions represent either large-scale loops with mass flowing along them
  (accounting for about one-fifth of the total mass flow in this example)
  or open magnetic field structures where the slow solar wind originates.

Title: Automated detection of filaments from He II images
Authors: Buchlin, E.; Mercier, C.; Vial, J. -C.
Bibcode: 2012EAS....55..175B
Altcode:
  For space weather applications, it is important to understand filaments
  evolution and especially their eruptions associated with coronal mass
  ejections. In view of the cadence and continuity of SDO observations,
  AIA and HMI offer a unique tool for such a program. Because of the
  data volume and the requirement of short latency, only an automated
  detection can be worked out. We present a new method for the automated
  detection and tracking of filaments, based on the analysis of AIA 30.4
  nm He ii images, with the capability to use also the magnetic field
  measured by HMI.

Title: The solar hydrogen Lyman α to Lyman β line ratio
Authors: Lemaire, P.; Vial, J. -C.; Curdt, W.; Schühle, U.; Woods,
   T. N.
Bibcode: 2012A&A...542L..25L
Altcode:
  <BR /> Aims: We investigate the variation in the solar hydrogen Lyman
  α (Lyα) to Lyman β (Lyβ) line ratio as a function of the solar
  activity by taking into account new results obtained by SoHO/SUMER
  and TIMED/SEE. <BR /> Methods: We reanalyze data of quiet and active
  regions previously collected with the LPSP multichannel instrument on
  OSO8. We then re-examine data obtained on the solar disk with SUMER
  and compare them with previous data. In a second step, we use the
  full Sun H i Lyβ profiles to determine the Lyβ contribution to the
  SEE profiles obtained with a 0.4 nm full width at half-maximum. The
  variation in the Lyα to Lyβ line ratio is then measured for part
  of the solar cycle 23 (2002-2008). <BR /> Results: We determine the
  radiance line ratio of the solar H i Lyα to Lyβ line for a quiet Sun
  area and the relation between the ratio of the Lyα to Lyβ irradiance
  and the Lyα solar irradiance.

Title: High spatial resolution VAULT H-Lyα observations and
    multiwavelength analysis of an active region filament
Authors: Vial, J. -C.; Olivier, K.; Philippon, A. A.; Vourlidas, A.;
   Yurchyshyn, V.
Bibcode: 2012A&A...541A.108V
Altcode:
  Context. The search for the fine structure of prominences has
  received considerable new attention thanks to the Swedish Solar
  Telescope (SST) Hα pictures that provide an unsurpassed spatial
  resolution. Recently, it has been shown that the filaments' coronal
  environment, at least for quiescent filaments, is perturbed by either
  cool absorbing material (in the EUV) or an "emissivity blocking"
  (actually a lack of transition region and coronal material). <BR />
  Aims: The aim is to assess the fine structure in an active region
  filament and to determine the nature of the EUV absorption or lack
  of emission phenomena, using the very optically thick line H-Lyα,
  formed at a temperature higher than Hα. <BR /> Methods: We performed
  a multiwavelength study where high-resolution imaging in the H-Lyα
  line (VAULT) was analysed and compared with observations of an active
  region filament in Hα (BBSO) and EUV lines (EIT and TRACE). <BR />
  Results: As for the SST data, small-scale structures were detected at
  a typical scale of about one to two arcseconds with, for some cuts,
  an indication of fine scales down to 0.4 arcsec in the optically thick
  H-Lyα line. The filament intensity relative to the intensity of the
  (active) region it is embedded in is about 0.2 in H-Lyα. This ratio
  (Lymanα ratio intensity or "LRI") is the lowest value compared to
  other lines, e.g. Hα. The filament environment was also investigated
  and evidence of an UV extension was found. The comparison of spatial
  cuts in different lines across the filament shows evidence of strong
  absorption, and consequently of cool plasma on one side of the filament,
  but not on the other (that side is obscured by the filament itself). <BR
  /> Conclusions: The absence of very fine structure in H-Lyα compared
  to Hα is explained by the formation temperature of the H-Lyα line
  (~20 000 K), where the transition regions of the thin threads begin to
  merge. From the detection of H-Lyα absorption on the observable side of
  the filament side, we derive the presence of absorbing (cool) material
  and possibly also of emissivity blocking (or coronal void). This poses
  the question whether these absorption effects are typical of active
  region filaments. <P />Appendix A is available in electronic form at
  <A href="http://www.aanda.org">http://www.aanda.org</A>

Title: Flows in the Vicinity of Two Active Regions as Seen by Hinode,
    STEREO, and SoHO
Authors: Boutry, C.; Buchlin, E'.; Vial, J.; Régnier, S.
Bibcode: 2012ASPC..455...83B
Altcode:
  We observed active region 10943 located at Sun center on February 20,
  2007 and we characterized its interactions with active region 10942 by
  using a multi-instrument comparison between Hinode/XRT and STEREO/SECCHI
  images, magnetic field maps from SoHO/MDI, and Hinode/EIS spectra
  from which we built maps of the Doppler shift and the intensity of the
  Fe XII 195.12 Å line. The results are consistent with some material
  exchange between the two regions separated by 400″.

Title: Kinematics and helicity evolution of a loop-like eruptive
    prominence
Authors: Koleva, K.; Madjarska, M. S.; Duchlev, P.; Schrijver, C. J.;
   Vial, J. -C.; Buchlin, E.; Dechev, M.
Bibcode: 2012A&A...540A.127K
Altcode: 2012arXiv1202.4541K
  <BR /> Aims: We aim at investigating the morphology as well as
  kinematic and helicity evolution of a loop-like prominence during its
  eruption. <BR /> Methods: We used multi-instrument observations from
  AIA/SDO, EUVI/STEREO and LASCO/SoHO. The kinematic, morphological,
  geometrical, and helicity evolution of a loop-like eruptive
  prominence were studied in the context of the magnetic flux rope
  model of solar prominences. <BR /> Results: The prominence eruption
  evolved as a height-expanding twisted loop with both legs anchored
  in the chromosphere of a plage area. The eruption process consisted
  of a prominence activation, acceleration, and a phase of constant
  velocity. The prominence body was composed of counter-clockwise twisted
  threads around the main prominence axis. The twist during the eruption
  was estimated at 6π (3 turns). The prominence reached a maximum height
  of 526 Mm before contracting to its primary location and was partially
  reformed in the same place two days after the eruption. This ejection,
  however, triggered a coronal mass ejection (CME) observed in LASCO
  C2. The prominence was located in the northern periphery of the CME
  magnetic field configuration and, therefore, the background magnetic
  field was asymmetric with respect to the filament position. The physical
  conditions of the falling plasma blobs were analysed with respect to
  the prominence kinematics. <BR /> Conclusions: The same sign of the
  prominence body twist and writhe, as well as the amount of twisting
  above the critical value of 2π after the activation phase indicate that
  possibly conditions for kink instability were present. No signature
  of magnetic reconnection was observed anywhere in the prominence body
  and its surroundings. The filament/prominence descent following the
  eruption and its partial reformation at the same place two days later
  suggest a confined type of eruption. The asymmetric background magnetic
  field possibly played an important role in the failed eruption. <P
  />Movies showing the temporal evolution are available in electronic
  form at <A href="http://www.aanda.org">http://www.aanda.org</A>

Title: Solar magnetism eXplorer (SolmeX). Exploring the magnetic
    field in the upper atmosphere of our closest star
Authors: Peter, Hardi; Abbo, L.; Andretta, V.; Auchère, F.; Bemporad,
   A.; Berrilli, F.; Bommier, V.; Braukhane, A.; Casini, R.; Curdt,
   W.; Davila, J.; Dittus, H.; Fineschi, S.; Fludra, A.; Gandorfer, A.;
   Griffin, D.; Inhester, B.; Lagg, A.; Landi Degl'Innocenti, E.; Maiwald,
   V.; Sainz, R. Manso; Martínez Pillet, V; Matthews, S.; Moses, D.;
   Parenti, S.; Pietarila, A.; Quantius, D.; Raouafi, N. -E.; Raymond, J.;
   Rochus, P.; Romberg, O.; Schlotterer, M.; Schühle, U.; Solanki, S.;
   Spadaro, D.; Teriaca, L.; Tomczyk, S.; Trujillo Bueno, J.; Vial, J. -C.
Bibcode: 2012ExA....33..271P
Altcode: 2011arXiv1108.5304P; 2011ExA...tmp..134P
  The magnetic field plays a pivotal role in many fields of
  Astrophysics. This is especially true for the physics of the solar
  atmosphere. Measuring the magnetic field in the upper solar atmosphere
  is crucial to understand the nature of the underlying physical
  processes that drive the violent dynamics of the solar corona—that
  can also affect life on Earth. SolmeX, a fully equipped solar space
  observatory for remote-sensing observations, will provide the first
  comprehensive measurements of the strength and direction of the
  magnetic field in the upper solar atmosphere. The mission consists
  of two spacecraft, one carrying the instruments, and another one in
  formation flight at a distance of about 200 m carrying the occulter to
  provide an artificial total solar eclipse. This will ensure high-quality
  coronagraphic observations above the solar limb. SolmeX integrates two
  spectro-polarimetric coronagraphs for off-limb observations, one in
  the EUV and one in the IR, and three instruments for observations on
  the disk. The latter comprises one imaging polarimeter in the EUV for
  coronal studies, a spectro-polarimeter in the EUV to investigate the low
  corona, and an imaging spectro-polarimeter in the UV for chromospheric
  studies. SOHO and other existing missions have investigated the emission
  of the upper atmosphere in detail (not considering polarization),
  and as this will be the case also for missions planned for the near
  future. Therefore it is timely that SolmeX provides the final piece of
  the observational quest by measuring the magnetic field in the upper
  atmosphere through polarimetric observations.

Title: Synthetic differential emission measure curves of prominence
    fine structures. II. The SoHO/SUMER prominence of 8 June 2004
Authors: Gunár, S.; Parenti, S.; Anzer, U.; Heinzel, P.; Vial, J. -C.
Bibcode: 2011A&A...535A.122G
Altcode:
  <BR /> Aims: This study is the first attempt to combine the prominence
  observations in Lyman, UV, and EUV lines with the determination of the
  prominence differential emission measure derived using two different
  techniques, one based on the inversion of the observed UV and EUV lines
  and the other employing 2D non-LTE prominence fine-structure modeling
  of the Lyman spectra. <BR /> Methods: We use a trial-and-error method
  to derive the 2D multi-thread prominence fine-structure model producing
  synthetic Lyman spectra in good agreement with the observations. We then
  employ a numerical method to perform the forward determination of the
  DEM from 2D multi-thread models and compare the synthetic DEM curves
  with those derived from observations using inversion techniques. <BR
  /> Results: A set of available observations of the June 8, 2004
  prominence allows us to determine the range of input parameters, which
  contains models producing synthetic Lyman spectra in good agreement
  with the observations. We select three models, which represent this
  parametric-space area well and compute the synthetic DEM curves for
  multi-thread realizations of these models. The synthetic DEM curves
  of selected models are in good agreement with the DEM curves derived
  from the observations. <BR /> Conclusions: We show that the evaluation
  of the prominence fine-structure DEM complements the analysis of the
  prominence hydrogen Lyman spectra and that its combination with the
  detailed radiative-transfer modeling of prominence fine structures
  provides a useful tool for investigating the prominence temperature
  structure from the cool core to the prominence-corona transition region.

Title: Hydrogen Lyα and Lyβ Radiances and Profiles in Polar
    Colornal Holes
Authors: Tian, Hui; Teriaca, Luca; Curdt, Werner; Vial, Jean-Claude
Bibcode: 2011shin.confE.166T
Altcode:
  The hydrogen Lyα plays a dominant role in the radiative energy
  transport in the lower transition region, and is important for
  the studies of transition-region structure as well as solar wind
  origin. We investigate the Lyα profiles obtained by the Solar
  Ultraviolet Measurement of Emitted Radiation spectrograph on the
  Solar and Heliospheric Observatory spacecraft in coronal holes and
  the quiet Sun. In a subset of these observations, the Hi Lyβ, Si III,
  and Ovi lines were also (quasi-)simultaneously recorded. We find that
  the distances between the two peaks of Lyα profiles are larger in
  coronal holes than in the quiet Sun, indicating a larger opacity in
  coronal holes. This difference might result from the different magnetic
  structures or the different radiation fields in the two regions. Most
  of the Lyβ profiles in the coronal hole have a stronger blue peak,
  in contrast to those in quiet-Sun regions while in both regions the
  Lyα profiles are stronger in the blue peak. Although the asymmetries
  are likely to be produced by differential flows in the solar atmosphere,
  their detailed formation processes are still unclear. The radiance ratio
  between Lyα and Lyβ decreases toward the limb in the coronal hole,
  which might be due to the different opacity of the two lines. We also
  find that the radiance distributions of the four lines are set by a
  combined effect of limb brightening and the different emission level
  between coronal holes and the quiet Sun.

Title: Automated detection of filaments in SDO data
Authors: Buchlin, É.; Mercier, C.; Engin, S.; Parenti, S.; Vial,
   J. -C.
Bibcode: 2010sf2a.conf..297B
Altcode:
  Solar eruption can eject billions of tons of plasma to the
  interplanetary space, with geophysical effects and impacts on human
  activities. The time constraints for space weather application as well
  as the huge volume of data that needs to be analyzed, especially since
  the launch of SDO, imply that the detection of solar filaments and their
  eruptions must be automated. Most current detection codes use Hα data,
  which are not available frequently enough for these applications. We
  present a new detection code that we have developed at IAS and that uses
  the high spatial and temporal-resolution SDO/AIA He II 30.4 nm data.

Title: Turbulence in the Solar Atmosphere and Solar Wind
Authors: Petrosyan, A.; Balogh, A.; Goldstein, M. L.; Léorat, J.;
   Marsch, E.; Petrovay, K.; Roberts, B.; von Steiger, R.; Vial, J. C.
Bibcode: 2010SSRv..156..135P
Altcode: 2010SSRv..tmp..117P
  The objective of this review article is to critically analyze turbulence
  and its role in the solar atmosphere and solar wind, as well as to
  provide a tutorial overview of topics worth clarification. Although
  turbulence is a ubiquitous phenomenon in the sun and its heliosphere,
  many open questions exist concerning the physical mechanisms of
  turbulence generation in solar environment. Also, the spatial and
  temporal evolution of the turbulence in the solar atmosphere and solar
  wind are still poorly understood. We limit the scope of this paper
  (leaving out the solar interior and convection zone) to the magnetized
  plasma that reaches from the photosphere and chromosphere upwards to
  the corona and inner heliosphere, and place particular emphasis on
  the magnetic field structures and fluctuations and their role in the
  dynamics and radiation of the coronal plasma. To attract the attention
  of scientists from both the fluid-dynamics and space-science communities
  we give in the first two sections a phenomenological overview of
  turbulence-related processes, in the context of solar and heliospheric
  physics and with emphasis on the photosphere-corona connection and
  the coupling between the solar corona and solar wind. We also discuss
  the basic tools and standard concepts for the empirical analysis and
  theoretical description of turbulence. The last two sections of this
  paper give a concise review of selected aspects of oscillations and
  waves in the solar atmosphere and related fluctuations in the solar
  wind. We conclude with some recommendations and suggest topics for
  future research.

Title: Definition of an imaging spectrometer meeting the needs of
    UV solar physics
Authors: Ruiz de Galarreta Fanjul, C.; Philippon, A.; Vial, J. -C.;
   Lemaire, P.; Maillard, J. -P.; Buisset, C.; Appourchaux, T.;
   Auchère, F.
Bibcode: 2010SPIE.7732E..36R
Altcode: 2010SPIE.7732E..99R
  The study of the outer solar atmosphere requires combining imaging
  and spectroscopy in the UV lines formed in the high chromosphere,
  the transition region and the corona. We start from the science
  requirements and we define the instrumental specifications in terms
  of field-of-view (FOV), spatial, temporal and spectral resolution and
  bandpass. We propose two different all-reflection optical architectures
  based on interferometric techniques: Spatial Heterodyne Spectroscopy
  (SHS); and Imaging Transform Spectrometer (IFTS). We describe the
  different set-ups and compare the potential performances of the two
  types of solutions, and discuss their feasibility. We conclude that
  IFTS appears to be the best solution, meeting the needs of UV solar
  physics. However, we point out the many difficulties to be encountered,
  especially as far as metrology is concerned.

Title: Physics of Solar Prominences: I—Spectral Diagnostics and
    Non-LTE Modelling
Authors: Labrosse, N.; Heinzel, P.; Vial, J. -C.; Kucera, T.; Parenti,
   S.; Gunár, S.; Schmieder, B.; Kilper, G.
Bibcode: 2010SSRv..151..243L
Altcode: 2010SSRv..tmp...34L; 2010arXiv1001.1620L
  This review paper outlines background information and covers recent
  advances made via the analysis of spectra and images of prominence
  plasma and the increased sophistication of non-LTE ( i.e. when there is
  a departure from Local Thermodynamic Equilibrium) radiative transfer
  models. We first describe the spectral inversion techniques that have
  been used to infer the plasma parameters important for the general
  properties of the prominence plasma in both its cool core and the
  hotter prominence-corona transition region. We also review studies
  devoted to the observation of bulk motions of the prominence plasma and
  to the determination of prominence mass. However, a simple inversion
  of spectroscopic data usually fails when the lines become optically
  thick at certain wavelengths. Therefore, complex non-LTE models become
  necessary. We thus present the basics of non-LTE radiative transfer
  theory and the associated multi-level radiative transfer problems. The
  main results of one- and two-dimensional models of the prominences and
  their fine-structures are presented. We then discuss the energy balance
  in various prominence models. Finally, we outline the outstanding
  observational and theoretical questions, and the directions for future
  progress in our understanding of solar prominences.

Title: Hanle signatures of the coronal magnetic field in the linear
    polarization of the hydrogen Lα line
Authors: Derouich, M.; Auchère, F.; Vial, J. C.; Zhang, M.
Bibcode: 2010A&A...511A...7D
Altcode: 2009arXiv0912.5068D
  <BR /> Aims: This paper is dedicated to the assessment of the validity
  of future coronal spectro-polarimetric observations and to prepare their
  interpretation in terms of the magnetic field vector. <BR /> Methods:
  We assume that the polarization of the hydrogen coronal Lα line is
  due to anisotropic scattering of an incident chromospheric radiation
  field. The anisotropy is due to geometrical effects but also to the
  inhomogeneities of the chromospheric regions which we model by using
  Carrington maps of the Lα. Because the corona is optically thin, we
  fully consider the effects of the integration over the line-of-sight
  (LOS). As a modeling case, we include a dipolar magnetic topology
  perturbed by a non-dipolar magnetic structure arising from a prominence
  current sheet in the corona. The spatial variation of the hydrogen
  density and the temperature is taken into account. We determine the
  incident radiation field developed on the tensorial basis at each
  point along the LOS. Then, we calculate the local emissivity vector
  to obtain integrated Stokes parameters with and without coronal
  magnetic field. <BR /> Results: We show that the Hanle effect is an
  interesting technique for interpreting the scattering polarization of
  the Lαλ1216 line in order to diagnose the coronal magnetic field. The
  difference between the calculated polarization and the zero magnetic
  field polarization gives us an estimation of the needed polarimetric
  sensitivity in future polarization observations. We also obtain
  useful indications about the optimal observational strategy. <BR />
  Conclusions: Quantitative interpretation of the Hanle effect on the
  scattering linear polarization of Lα line can be a crucial source
  of information about the coronal magnetic field at a height over the
  limb h &lt; 0.7 R<SUB>⊙</SUB>. Therefore, one needs the development
  of spatial instrumentation to observe this line. <P />Present address:
  Colorado Research Associates Division, NorthWest Research Associates,
  Inc., 3380 Mitchell Ln., Boulder, CO 80301, USA.

Title: Space solar missions
Authors: Vial, Jean-Claude
Bibcode: 2010IAUS..264..459V
Altcode:
  In the frame of Symposium 264 which concerns Solar and Stellar
  Variability we address the space solar missions devoted to the various
  aspects of solar activity. We describe them in three time categories:
  missions ready for launch, missions which will operate in the 2012-2015
  time frame and ambitious missions to be launched after 2015. We focus
  on the contributions of these missions according to the following
  criteria: Understanding mechanisms of activity, Improving detection
  and characterisation, Working out some prediction. Major activity
  contributors and manifestations are addressed: Coronal Mass Ejections,
  Flares, Solar winds, Magnetism (including dynamo), Irradiance.

Title: Discussion with the HMI Team representative
Authors: Vial, Jean-Claude
Bibcode: 2010cosp...38.2865V
Altcode: 2010cosp.meet.2865V
  Discussion with the HMI Team representative after her presentation

Title: Automated detection of filaments and their eruptions from
    AIA and HMI/SDO data
Authors: Buchlin, Eric; Mercier, Claude; Vial, Jean-Claude
Bibcode: 2010cosp...38.2862B
Altcode: 2010cosp.meet.2862B
  The superior temporal, spatial and spectral range of AIA on SDO provides
  a completely new view of the dynamic nature of coronal loops. In this
  paper, we will examine preliminary results of a number of loop examples
  as their evolution is followed closely in time and space across the
  AIA filters. The implications of these observational results on the
  heating and cooling mechanisms operating will be discussed.

Title: The SDO data centre at IDOC/MEDOC in France
Authors: Parenti, Susanna; Bocchialini, Karine; Soubrie, Elie;
   Auchere, Frederic; Ballans, Herv; Buchlin, Eric; Gabriel, Alan;
   Mercier, Claude; Poulleau, Gilles; Vial, Jean-Claude
Bibcode: 2010cosp...38.2888P
Altcode: 2010cosp.meet.2888P
  The IDOC/MEDOC centre at the Institut d'Astrophysique Spatiale (IAS,
  Université Paris 11/CNRS) has a long experience in solar data archiving
  and distribution, including almost 15 years of data from SOHO, STEREO
  and TRACE. The center is now expanding its activity and becoming a
  Pˆle Thématique Solaire of the CNES and INSU/CNRS. Part of the new
  activities of the centre will be linked to the arrival of the enormous
  volume of the new SDO data. The center will be one of the three European
  centers to receive and redistribute the data to the community. It will
  also be the only European site to permanently store about 10% of the
  data (mainly from AIA). In continuity with its previous activities,
  SDO data will be included in the data visualization tool FESTIVAL
  and it will provide new services, like tools for the solar feature
  identification (filaments, EUV intensity fluctuations). We will present
  an overview of the facilities and activities of the centre in relation
  to the SDO data.

Title: Discussion with EVE PI
Authors: Vial, Jean-Claude
Bibcode: 2010cosp...38.2872V
Altcode: 2010cosp.meet.2872V
  Discussion with EVE PI after his presentation

Title: Large-scale Extreme-Ultraviolet Disturbances Associated with
    a Limb Coronal Mass Ejection
Authors: Dai, Y.; Auchère, F.; Vial, J. -C.; Tang, Y. H.; Zong, W. G.
Bibcode: 2010ApJ...708..913D
Altcode:
  We present composite observations of a coronal mass ejection (CME)
  and the associated large-scale extreme-ultraviolet (EUV) disturbances
  on 2007 December 31 by the Extreme-ultraviolet Imager (EUVI) and COR1
  coronagraph on board the recent Solar Terrestrial Relations Observatory
  mission. For this limb event, the EUV disturbances exhibit some typical
  characteristics of EUV Imaging Telescope waves: (1) in the 195 Å
  bandpass, diffuse brightenings are observed propagating oppositely
  away from the flare site with a velocity of ~260 km s<SUP>-1</SUP>,
  leaving dimmings behind; (2) when the brightenings encounter the
  boundary of a polar coronal hole, they stop there to form a stationary
  front. Multi-temperature analysis of the propagating EUV disturbances
  favors a heating process over a density enhancement in the disturbance
  region. Furthermore, the EUVI-COR1 composite display shows unambiguously
  that the propagation of the diffuse brightenings coincides with a
  large lateral expansion of the CME, which consequently results in a
  double-loop-structured CME leading edge. Based on these observational
  facts, we suggest that the wave-like EUV disturbances are a result of
  magnetic reconfiguration related to the CME liftoff rather than true
  waves in the corona. Reconnections between the expanding CME magnetic
  field lines and surrounding quiet-Sun magnetic loops account for the
  propagating diffuse brightenings; dimmings appear behind them as a
  consequence of volume expansion. X-ray and radio data provide us with
  complementary evidence.

Title: Discussion with AIA PI
Authors: Vial, Jean-Claude
Bibcode: 2010cosp...38.2860V
Altcode: 2010cosp.meet.2860V
  Discussion with the PI after his presentation

Title: Poster session
Authors: Vial, Jean-Claude
Bibcode: 2010cosp...38.2870V
Altcode: 2010cosp.meet.2870V
  Poster presentation

Title: Hydrogen Lyα and Lyβ Radiances and Profiles in Polar
    Coronal Holes
Authors: Tian, Hui; Teriaca, Luca; Curdt, Werner; Vial, Jean-Claude
Bibcode: 2009ApJ...703L.152T
Altcode: 2009arXiv0909.0735T
  The hydrogen Lyα plays a dominant role in the radiative energy
  transport in the lower transition region, and is important for
  the studies of transition-region structure as well as solar wind
  origin. We investigate the Lyα profiles obtained by the Solar
  Ultraviolet Measurement of Emitted Radiation spectrograph on the
  Solar and Heliospheric Observatory spacecraft in coronal holes and the
  quiet Sun. In a subset of these observations, the H I Lyβ, Si III,
  and O VI lines were also (quasi-)simultaneously recorded. We find
  that the distances between the two peaks of Lyα profiles are larger
  in coronal holes than in the quiet Sun, indicating a larger opacity in
  coronal holes. This difference might result from the different magnetic
  structures or the different radiation fields in the two regions. Most
  of the Lyβ profiles in the coronal hole have a stronger blue peak,
  in contrast to those in quiet-Sun regions while in both regions the
  Lyα profiles are stronger in the blue peak. Although the asymmetries
  are likely to be produced by differential flows in the solar atmosphere,
  their detailed formation processes are still unclear. The radiance ratio
  between Lyα and Lyβ decreases toward the limb in the coronal hole,
  which might be due to the different opacity of the two lines. We also
  find that the radiance distributions of the four lines are set by a
  combined effect of limb brightening and the different emission level
  between coronal holes and the quiet Sun.

Title: Solar source of energetic particles in interplanetary space
    during the 2006 December 13 event
Authors: Li, C.; Dai, Y.; Vial, J. -C.; Owen, C. J.; Matthews, S. A.;
   Tang, Y. H.; Fang, C.; Fazakerley, A. N.
Bibcode: 2009A&A...503.1013L
Altcode: 2013arXiv1305.5593L
  An X3.4 solar flare and a fast halo coronal mass ejection (CME)
  occurred on 2006 December 13, accompanied by a high flux of energetic
  particles recorded both in near-Earth space and at ground level. Our
  purpose is to provide evidence of flare acceleration in a major solar
  energetic particle (SEP) event. We first present observations from
  ACE/EPAM, GOES, and the Apatity neutron monitor. It is found that the
  initial particle release time coincides with the flare emission and
  that the spectrum becomes softer and the anisotropy becomes weaker
  during particle injection, indicating that the acceleration source
  changes from a confined coronal site to a widespread interplanetary
  CME-driven shock. We then describe a comprehensive study of the
  associated flare active region. By use of imaging data from HINODE/SOT
  and SOHO/MDI magnetogram, we infer the flare magnetic reconnection
  rate in the form of the magnetic flux change rate. This correlates in
  time with the microwave emission, indicating a physical link between
  the flare magnetic reconnection and the acceleration of nonthermal
  particles. Combining radio spectrograph data from Huairou/NOAC,
  Culgoora/IPS, Learmonth/RSTN, and WAVES/WIND leads to a continuous
  and longlasting radio burst extending from a few GHz down to several
  kHz. Based on the photospheric vector magnetogram from Huairou/NOAC
  and the nonlinear force free field (NFFF) reconstruction method,
  we derive the 3D magnetic field configuration shortly after the
  eruption. Furthermore, we also compute coronal field lines extending
  to a few solar radii using a potential-field source-surface (PFSS)
  model. Both the so-called type III-l burst and the magnetic field
  configuration suggest that open-field lines extend from the flare
  active region into interplanetary space, allowing the accelerated and
  charged particles escape.

Title: Electron density in the quiet solar coronal transition region
    from SoHO/SUMER measurements of S VI line radiance and opacity
Authors: Buchlin, E.; Vial, J. -C.
Bibcode: 2009A&A...503..559B
Altcode: 2009arXiv0906.1367B
  Context: The steep temperature and density gradients that are measured
  in the coronal transition region challenge the model interpretation
  of observations. <BR />Aims: We derive the average electron density
  &lt; n<SUB>e</SUB> &gt; in the region emitting the S vi lines. We use
  two different techniques, which allow us to derive linearly-weighted
  (opacity method) and quadratically-weighted (emission measure method)
  electron density along the line-of-sight, to estimate a filling factor
  or derive the layer thickness at the formation temperature of the
  lines. <BR />Methods: We analyze SoHO/SUMER spectroscopic observations
  of the S vi lines, using the center-to-limb variations in radiance,
  the center-to-limb ratios of radiance and line width, and the radiance
  ratio of the 93.3-94.4 nm doublet to derive the opacity. We also
  use the emission measure derived from radiance at disk center. <BR
  />Results: We derive an opacity τ<SUB>0</SUB> at S vi 93.3 nm line
  center of the order of 0.05. The resulting average electron density
  &lt; {n<SUB>e</SUB>}&gt;, under simple assumptions concerning the
  emitting layer, is 2.4 × 10<SUP>16</SUP> m<SUP>-3</SUP> at T = 2 ×
  10<SUP>5</SUP> K. This value is higher than (and inconsistent with)
  the values obtained from radiance measurements (2 × 10<SUP>15</SUP>
  m<SUP>-3</SUP>). The last value corresponds to an electron pressure
  of 10<SUP>-2</SUP> Pa. Conversely, taking a classical value for the
  density leads to a too high value of the thickness of the emitting
  layer. <BR />Conclusions: The pressure derived from the emission
  measure method compares well with previous determinations. It implies
  a low opacity of between 5 × 10<SUP>-3</SUP> and 10<SUP>-2</SUP>. It
  remains unexplained why a direct derivation leads to a much higher
  opacity, despite tentative modeling of observational biases. Further
  measurements in S vi and other lines emitted at a similar temperature
  should be completed, and more realistic models of the transition region
  need to be used.

Title: The He II Lines in the Lyman Series Profiles of Solar
    Prominences
Authors: Ebadi, H.; Vial, J. -C.; Ajabshirizadeh, A.
Bibcode: 2009SoPh..257...91E
Altcode:
  The hydrogen and helium lines are the most prominent lines in the solar
  prominences spectra. Observations with the SUMER spectrometer onboard
  SOHO showed that there are weak lines in the blue wings of the Lyman
  series which affect their profiles. They were all identified as He II
  lines in the Lyman series wings, except for the Lα line whose profile
  was affected by the use of an attenuator. The He II lines are the even
  Balmer lines of the He II system, a set of lines that we complete with
  the odd ones. We characterize them by comparison with the blue wings of
  the Lyman series in order to improve the H Lyman series observations
  and modeling, on one hand and to provide He II lines observations for
  further combined H - He I - He II modeling, on the other hand.

Title: Polarimetry of the Lα Line for Coronal Magnetic Field
    Diagnostic
Authors: Derouich, M.; Auchère, F.; Vial, J. C.; Millard, A. A.
Bibcode: 2009ASPC..405..389D
Altcode:
  Measurement and physical interpretation of the scattering polarization
  of the Extreme-ultraviolet (EUV) and Far-UV (FUV) spectral lines
  provide a largely unexplored diagnostic of coronal magnetic field. In
  this context, we present the LYOT (LYman Orbiting Telescope) project
  that makes it possible to observe the Lα λ1216 line polarization
  in the solar corona. Because the corona is optically thin, it
  is necessary to consider the effects of the integration over the
  line-of-sight (LOS). The LOS effects have been usually addressed for
  non polarimetric studies where the unknown is a scalar quantity (the
  intensity) but not a Stokes vector. Previous studies investigating the
  coronal polarization are generally concerned with a local position of
  the scattering center and a deterministic magnetic field (see Raouafi
  et al.~2002 for a measurement and interpretation of the O VI λ 1032
  line polarization). Here, we perform computations that test whether
  a LOS integrated Hanle effect can be detected in order to access to
  the magnetic field topology.

Title: Diagnostics of active and eruptive prominences through hydrogen
    and helium lines modelling
Authors: Labrosse, N.; Vial, J. -C.; Gouttebroze, P.
Bibcode: 2008AnGeo..26.2961L
Altcode: 2008arXiv0804.4625L
  In this study we show how hydrogen and helium lines modelling can be
  used to make a diagnostic of active and eruptive prominences. One
  motivation for this work is to identify the physical conditions
  during prominence activation and eruption. Hydrogen and helium
  lines are key in probing different parts of the prominence structure
  and inferring the plasma parameters. However, the interpretation of
  observations, being either spectroscopic or obtained with imaging, is
  not straightforward. Their resonance lines are optically thick, and
  the prominence plasma is out of local thermodynamic equilibrium due
  to the strong incident radiation coming from the solar disk. In view
  of the shift of the incident radiation occuring when the prominence
  plasma flows radially, it is essential to take into account velocity
  fields in the prominence diagnostic. Therefore we need to investigate
  the effects of the radial motion of the prominence plasma on hydrogen
  and helium lines. The method that we use is the resolution of the
  radiative transfer problem in the hydrogen and helium lines out of
  local thermodynamic equilibrium. We study the variation of the computed
  integrated intensities in H and He lines with the radial velocity of
  the prominence plasma. We can confirm that there exist suitable lines
  which can be used to make a diagnostic of the plasma in active and
  eruptive prominences in the presence of velocity fields.

Title: The Lyman-alpha Line in Active and Eruptive Solar Prominences
Authors: Labrosse, N.; Vial, J. -C.
Bibcode: 2008ESPM...12.3.17L
Altcode:
  We investigate the effects of radial motions on the Ly-alpha emission
  in moving prominences under various temperature and pressure conditions
  and for various prominence masses. The ability to compute the Ly-alpha
  line intensity in active and erupting prominences with our non-LTE
  radiative transfer code is especially relevant to VAULT and to
  the LYOT instrument on SMESE. In the case of erupting prominences,
  high-cadence imaging as anticipated from LYOT/SMESE, will allow us
  to observe the dimming of the line as the prominence expands in the
  radial direction. In conjunction with our non-LTE radiative transfer
  code, the diagnostic of the thermodynamical plasma parameters and the
  velocity field can be done. This should provide new constraints for
  models of filament and prominence eruptions.

Title: Properties of the quiet solar coronal transition region from
    full-Sun SoHO/SUMER S VI
Authors: Buchlin, E.; Vial, J.
Bibcode: 2008ESPM...122.117B
Altcode:
  A series of full-Sun SoHO/SUMER observations of the quiet Sun in the
  transition region lines S VI 933 and 944 (as well as Ly epsilon) has
  been performed during year 1996. We use this unique data set to derive
  the opacity of the S VI lines by different methods (following Dumont et
  al. 1983), taking advantage from the availability of full-Sun data and
  <P />of the S VI doublet: 1. using the center-to-limb variations of S
  VI 933 radiance and peak spectral radiance, 2. using the center-to-limb
  variations of S VI 933 line width and radiance, and 3. using the S VI
  944 - 933 radiance or spectral radiance ratio at disk center. We then
  deduce an average value for the density in the S VI emitting region
  (in the coronal transition region). By comparing this value to the
  average square density obtained by an Emission Measure analysis,
  we get a tentative estimate of the filling factor in this region.

Title: The HeII (and DI) Lines in the Lyman Series of Solar
    Prominences
Authors: Vial, J. -C.; Ebadi, H.; Ajabshirizadeh, A.
Bibcode: 2008ESPM...12.2.20V
Altcode:
  The hydrogen lines are the most prominent lines in solar prominence
  spectra. Observations with the SUMER spectrometer on board SoHO showed
  that there are weak emission lines in the blue wings of the Lyman
  series which affect their profiles. We identified them as D I and
  He II lines in the Lyman alpha profile and He II lines in the upper
  Lyman series wings. The He II lines are identified as Balmer lines
  of He II. We attempt to characterize these lines in the blue wings
  of the Lyman series and consequently to provide supplementary He II
  information for further He I-He II non-LTE modelling.

Title: Developing a CME-Associated Phenomena Catalog for SDO
Authors: Wills-Davey, M. J.; Davey, A. R.; Vial, J.
Bibcode: 2008AGUSMSP51B..12W
Altcode:
  With the anticipated launch of the Solar Dynamics Observatory (SDO),
  we have embarked on the development of an automated detection scheme
  which will correlate and catalog CME-associated phenomena with CME
  observations from existing coronagraphs. Observing primarily using the
  Atmospheric Imaging Assembly (AIA), the SDO CME catalog will focus on
  various aspects of CME initiation and development, including automated
  measurement of coronal dimming regions at CME onset, the detection of
  filament eruptions in near-real time, and the automated tracking of
  CME fronts in coronagraph data.

Title: A Time-Evolving 3D Method Dedicated to the Reconstruction of
    Solar Plumes and Results Using Extreme Ultraviolet Data
Authors: Barbey, Nicolas; Auchère, Frédéric; Rodet, Thomas; Vial,
   Jean-Claude
Bibcode: 2008SoPh..248..409B
Altcode: 2008SoPh..tmp...65B; 2008arXiv0802.0113B
  An important issue in the tomographic reconstruction of the solar poles
  is the relatively rapid evolution of the polar plumes. We demonstrate
  that it is possible to take into account this temporal evolution in
  the reconstruction. The difficulty of this problem comes from the fact
  that we want a four-dimensional reconstruction (three spatial dimensions
  plus time) whereas we only have three-dimensional data (two-dimensional
  images plus time). To overcome this difficulty, we introduce a model
  that describes polar plumes as stationary objects whose intensity varies
  homogeneously with time. This assumption can be physically justified
  if one accepts the stability of the magnetic structure. This model
  leads to a bilinear inverse problem. We describe how to extend linear
  inversion methods to these kinds of problems. Studies of simulations
  show the reliability of our method. Results for SOHO/EIT data show
  that we can estimate the temporal evolution of polar plumes to improve
  the reconstruction of the solar poles from only one point of view. We
  expect further improvements from STEREO/EUVI data when the two probes
  will be separated by about 60°.

Title: Polarisation and magnetic depolarization of the Lyman-alpha
line in the corona : the line-of-sight effects
Authors: Vial, Jean-Claude; Derouich, Moncef; Auchere, Frederic;
   Zhang, Mei
Bibcode: 2008cosp...37.3340V
Altcode: 2008cosp.meet.3340V
  In view of the importance of measuring coronal magnetic field and of
  the capability of measuring linear polarization in the Lyman α line
  with the LYOT coronagraph on board the SMESE mission, we carried out
  some calculations of the degrees of depolarization resulting from the
  presence of a magnetic field. Our calculation is based on a simple
  magnetic field model where a current sheet in the field represents
  a solar prominence. We focus in this study on the effect of the
  line-of-sight integration at various locations in the corona on the
  polarizing/depolarizing properties. Other magnetic configurations are
  also considered and are under the study.

Title: Solar prominence properties derived from the UV-EUV SUMER
    spectral atlas
Authors: Parenti, S.; Vial, J. -C.; Lemaire, P.
Bibcode: 2008AdSpR..41..144P
Altcode:
  In this paper, we summarize the work done to build a UV-EUV spectral
  atlas of a prominence and we introduce some recent scientific
  results obtained from these data. For this work we used SOHO/SUMER
  data covering the full wavelength range accessible by the instrument
  (from about 800 to 1600 Å), when a prominence and the quiet Sun (used
  as spectral reference) were observed in October 1998. We present here
  only a fraction of the data, which results in the analysis of more
  than 600 spectral lines, including some new identifications. Here we
  also present the differential emission measure obtained from the data,
  both for the quiet Sun and the prominence. The main differences in
  characteristics are discussed.

Title: The Reversal Behavior of Some Hydrogen Lyman Lines in Solar
    Spicules
Authors: Ajabshirizadeh, Ali; Ajabshirizadeh, Ali; Vial, Jean-Claude;
   Fathi-Vavsari, Hassan; Ebadi, Hossein
Bibcode: 2008cosp...37...42A
Altcode: 2008cosp.meet...42A
  Spicules are the dominant component of the quiet solar chromosphere. At
  the solar limb they appear as jet-like dynamic structures extending into
  the solar corona. The physical processes that generate spicules have
  not yet been uniquely identified. In this work, we analyze spicules
  data taken by the SUMER spectrometer on-board SoHO in the Lyman Beta
  and Lyman Gamma lines. A similar analysis has been done already by
  Vial et al. (2007) in Lyman alpha and Lyman beta lines. The data used
  have a spatial resolution of one arcsec along the slit and a spectral
  resolution of about 44 mA. We applied the standard procedures for
  geometric distortion, flat- fielding and dead time corrections, which
  can be found in the Solar Software (SSW) database. Our results show that
  in spicules both Lyman beta and Lyman gamma line profiles are reversed
  at all altitudes; on the contrary, in the prominence, the Lyman beta
  and Lyman gamma line profiles are reversed only at higher altitude,
  while at lower altitude they are clearly non-reversed in accordance
  with Vial et al. (2007). We provide some explanation for this behavior.

Title: SMESE (SMall Explorer for Solar Eruptions): A microsatellite
    mission with combined solar payload
Authors: Vial, J. -C.; Auchère, F.; Chang, J.; Fang, C.; Gan, W. Q.;
   Klein, K. -L.; Prado, J. -Y.; Rouesnel, F.; Sémery, A.; Trottet,
   G.; Wang, C.
Bibcode: 2008AdSpR..41..183V
Altcode:
  The SMESE (SMall Explorer for Solar Eruptions) mission is a
  microsatellite proposed by France and China. The payload of SMESE
  consists of three packages: LYOT (a Lyman α imager and a Lyman α
  coronagraph), DESIR (an Infra-red Telescope working at 35 80 and
  100 250 μm), and HEBS (a High Energy Burst Spectrometer working
  in X- and gamma-rays). The scientific objectives of the mission are
  shortly presented. We describe the three instrumental packages and the
  profile of the mission which accommodates them. With a launch around
  2012 2013, the SMESE microsatellite mission will provide a unique
  tool for detecting and understanding eruptions (flares and coronal
  mass ejections). Observations should start around solar maximum, and
  continue in the declining phase of activity, at a time when the Solar
  Dynamics Observatory (SDO) should still be operating.

Title: The Ly α and Ly β Profiles in Solar Prominences and
    Prominence Fine Structure
Authors: Vial, J. -C.; Ebadi, H.; Ajabshirizadeh, A.
Bibcode: 2007SoPh..246..327V
Altcode: 2007arXiv0710.1433V
  Ly α and Ly β line profiles in a solar prominence were observed with
  high spatial and spectral resolution with SOHO/SUMER. Within a 60-arcsec
  scan, we measure a very large variety of profiles: not only reversed
  and nonreversed profiles but also red-peaked and blue-peaked ones in
  both lines. Such a spatial variability is probably related to both
  the fine structure in prominences and the different orientations of
  mass motions. The usage of integrated-intensity cuts along the SUMER
  slit allowed us to categorize the prominence in three regions. We
  computed average profiles and integrated intensities in these
  lines in the range 2.36 - 42.3 W m<SUP>−2</SUP> sr<SUP>−1</SUP>
  for Ly α and 0.027 - 0.237 W m<SUP>−2</SUP> sr<SUP>−1</SUP>
  for Ly β. As shown by theoretical modeling, the Ly α/Ly β ratio
  is very sensitive to geometrical and thermodynamic properties of
  fine structure in prominences. For some pixels, and in both lines,
  we found agreement between observed intensities and those predicted
  by one-dimensional models. But a close examination of the profiles
  indicated a rather systematic disagreement concerning their detailed
  shapes. The disagreement between observations and thread models (with
  ambipolar diffusion) leads us to speculate about the importance of
  the temperature gradient between the cool and coronal regions. This
  gradient could depend on the orientation of field lines as proposed
  by Heinzel, Anzer, and Gunár (Astron. Astrophys.442, 331, 2005).

Title: Flare magnetic reconnection and relativistic particles in
    the 2003 October 28 event
Authors: Li, C.; Tang, Y. H.; Dai, Y.; Fang, C.; Vial, J. -C.
Bibcode: 2007A&A...472..283L
Altcode: 2007arXiv0706.3648L
  An X17.2 solar flare occurred on 2003 October 28, accompanied by
  multi-wavelength emissions and a high flux of relativistic particles
  observed at 1 AU. We present the analytic results of the TRACE, SOHO,
  RHESSI, ACE, GOES, hard X-ray (INTEGRAL satellite), radio (Ondeřejov
  radio telescope), and neutron monitor data. It is found that the
  inferred magnetic reconnection electric field correlates well with the
  hard X-ray, gamma-ray, and neutron emission at the Sun. Thus the flare's
  magnetic reconnection probably makes a crucial contribution to the
  prompt relativistic particles, which could be detected at 1 AU. Since
  the neutrons were emitted a few minutes before the injection of protons
  and electrons, we propose a magnetic-field evolution configuration to
  explain this delay. We do not exclude the effect of CME-driven shock,
  which probably plays an important role in the delayed gradual phase
  of solar energetic particles.

Title: Prominence and quiet-Sun plasma parameters derived from FUV
    spectral emission
Authors: Parenti, S.; Vial, J. -C.
Bibcode: 2007A&A...469.1109P
Altcode:
  Context: A solar prominence and the quiet-Sun (QS) were observed
  with SOHO/SUMER in October 1999. With this dataset we built the
  first comprehensive UV spectral atlas in the range 800-1250 Å for a
  prominence, thus complementing the existing reference atlases for the
  QS. <BR />Aims: This is a detailed study based on the information
  in this atlas, with the aim of deriving the plasma parameters in
  two distinct regions. The large amount of information available
  allows us to establish these parameters with lower uncertainty than
  in previous studies, leading to reference values for theoretical
  investigations. <BR />Methods: The measured lines' FWHM were used
  to derive the distribution of the non-thermal velocities at various
  temperatures. The lines intensities were used to derive the electron
  densities at temperatures of 7 × 10<SUP>4</SUP> K and the differential
  emission measure. <BR />Results: The comparison with the QS shows
  lower velocities in the prominence for temperature T with log~T &lt;
  5.4. The velocities derived in the highest part of the prominence
  show a lower gradient with the temperature. The value obtained for
  the electron density indicates a low pressure prominence. We conclude
  with a discussion of the energy budget in the prominence. <P />Table
  1 is only available in electronic form at http://www.aanda.org

Title: Spectral Diagnostics of Active Prominences
Authors: Labrosse, N.; Gouttebroze, P.; Vial, J. -C.
Bibcode: 2007ASPC..368..337L
Altcode: 2006astro.ph.11488L
  Active prominences exhibit plasma motions, resulting in difficulties
  with the interpretation of spectroscopic observations. These solar
  features being strongly influenced by the radiation coming from
  the solar disk, Doppler dimming or brightening effects may arise,
  depending on which lines are observed and on the velocity of the
  plasma. Interlocking between the different atomic energy levels and
  non local thermodynamic equilibrium lead to non-trivial spectral line
  profiles, and this calls for complex numerical modeling of the radiative
  transfer in order to understand the observations. We present such a
  tool, which solves the radiative transfer and statistical equilibrium
  for H, He I, He II, and Ca II in moving prominences where radial plasma
  motions are taking place. It is found that for isothermal, isobaric
  prominence models, the He II resonance lines are very sensitive to the
  Doppler effect and thus show a strong Doppler dimming. The Ca II lines
  Doppler effect for the prominence models considered here. We illustrate
  how the code makes it possible to retrieve the plasma thermodynamic
  parameters by comparing computed and observed line profiles of
  hydrogen and helium resonance lines in a quiescent prominence. This
  new non-LTE radiative transfer code including velocities allows us
  to better understand the formation of several lines of importance in
  prominences, and in conjunction with observations, infer the prominence
  plasma thermodynamic properties and full velocity vector.

Title: Effect of motions in prominences on the helium resonance
    lines in the extreme ultraviolet
Authors: Labrosse, N.; Gouttebroze, P.; Vial, J. -C.
Bibcode: 2007A&A...463.1171L
Altcode: 2006astro.ph..8221L
  Context: Extreme ultraviolet resonance lines of neutral and ionised
  helium observed in prominences are difficult to interpret as the
  prominence plasma is optically thick at these wavelengths. If mass
  motions are taking place, as is the case in active and eruptive
  prominences, the diagnostic is even more complex. <BR />Aims: We aim
  at studying the effect of radial motions on the spectrum emitted by
  moving prominences in the helium resonance lines and at facilitating the
  interpretation of observations, in order to improve our understanding
  of these dynamic structures. <BR />Methods: We develop our non-local
  thermodynamic equilibrium radiative transfer code formerly used
  for the study of quiescent prominences. The new numerical code is
  now able to solve the statistical equilibrium and radiative transfer
  equations in the non-static case by using velocity-dependent boundary
  conditions for the solution of the radiative transfer problem. This
  first study investigates the effects of different physical conditions
  (temperature, pressure, geometrical thickness) on the emergent helium
  radiation. <BR />Results: The motion of the prominence plasma induces
  a Doppler dimming effect on the resonance lines of He I and He II. The
  velocity effects are particularly important for the He II λ 304 Å line
  as it is mostly formed by resonant diffusion of incident radiation under
  prominence conditions. The He I resonance lines at 584 and 537 Å also
  show some sensitivity to the motion of the plasma, all the more when
  thermal emission is not too important in these lines. We also show
  that it is necessary to consider partial redistribution in frequency
  for the scattering of the incident radiation. <BR />Conclusions: .This
  set of helium lines offers strong diagnostic possibilities that can be
  exploited with the SOHO spectrometers and with the EIS spectrometer on
  board the Hinode satellite. The addition of other helium lines and of
  lines from other elements (in particular hydrogen) in the diagnostics
  will further enhance the strength of the method. <P />Figures [see
  full text], [see full text] and [see full text] are only available in
  electronic form at http://www.aanda.org

Title: A Contribution to the Understanding of Chromospheric
    Oscillations
Authors: Baudin, F.; Ibarra, E.; Avrett, E. H.; Vial, J. -C.;
   Bocchialini, K.; Costa, A.; Lemaire, P.; Rovira, M.
Bibcode: 2007SoPh..241...39B
Altcode:
  We present SUMER/SOHO UV measurements of chromospheric oscillations
  of intensity, velocity, and linewidth observed in C I, S I, O I, and
  C II lines, which are formed in the altitude range from 1000 km to
  2000 km above τ<SUB>500</SUB>=1. Oscillations in lines originating
  at similar altitudes exhibit different behaviors which we discuss in
  terms of the formation of the lines.

Title: Coronal Turbulence And Intermittency From Solar Orbiter
    Observations
Authors: Buchlin, É.; Vial, J. -C.
Bibcode: 2007ESASP.641E..23B
Altcode:
  Turbulent motions and magnetic fields are a key component of coronal
  heating mechanisms. They are indeed likely to produce the small scales
  at which the mechanisms such as reconnection are efficient enough. The
  properties of turbulence (and the associated intermit- tency) may thus
  have an influence on the energy dissipation in the corona, and need to
  be characterized from observations. Although turbulence is omnipresent
  from the Sun to the heliosphere, good observations of MHD turbulence
  have not yet been performed in the corona, in lines emitted at high
  temperature, where the heating actually occurs. We propose a study
  of coordinated EUS- EUI-VIM observations, with better resolution and
  counting statistics than ever before, whose main goal is to get and
  interpret the spatial statistics (spectra and structure functions)
  of the velocity field in lines emitted at high temperatures (log10
  T ≥ 6.4), together with the plasma and magnetic environment of the
  observed region. These statistics will help us understand the precise
  role of coronal turbulence in the coronal heating processes.

Title: SMESE: A SMall Explorer for Solar Eruptions
Authors: Vial, J. -C.; Auchère, F.; Chang, J.; Fang, C.; Gan, W. Q.;
   Klein, K. -L.; Prado, J. -Y.; Trottet, G.; Wang, C.; Yan, Y. H.
Bibcode: 2007AdSpR..40.1787V
Altcode:
  The SMall Explorer for Solar Eruptions (SMESE) mission is a
  microsatellite proposed by France and China. The payload of SMESE
  consists of three packages: LYOT (a Lyman α imager and a Lyman α
  coronagraph), DESIR (an Infra-Red Telescope working at 35-80 and
  100-250 μm), and HEBS (a High-Energy Burst Spectrometer working in
  X- and γ-rays). The status of research on flares and coronal mass
  ejections is briefly reviewed in the context of on-going missions such
  as SOHO, TRACE and RHESSI. The scientific objectives and the profile of
  the mission are described. With a launch around 2012-2013, SMESE will
  provide a unique tool for detecting and understanding eruptions (flares
  and coronal mass ejections) close to the maximum phase of activity.

Title: EUI, The Ultraviolet Imaging Telescopes Of Solar Orbiter
Authors: Hochedez, J. -F.; Appourchaux, T.; Defise, J. -M.; Harra,
   L. K.; Schühle, U.; Auchère, F.; Curdt, W.; Hancock, B.; Kretzschmar,
   M.; Lawrence, G.; Leclec'h, J. -C.; Marsch, E.; Mercier, R.; Parenti,
   S.; Podladchikova, E.; Ravet, M. -F.; Rochus, P.; Rodriguez, L.;
   Rouesnel, F.; Solanki, S.; Teriaca, L.; Van Driel, L.; Vial, J. -C.;
   Winter, B.; Zhukov, A.
Bibcode: 2007ESASP.641E..33H
Altcode:
  The scientific objectives of Solar Orbiter rely ubiquitously on EUI,
  its suite of solar atmosphere imaging telescopes. In the configuration
  discussed here, EUI includes three co-aligned High Resolution Imagers
  (HRI) and one Full Sun Imager (FSI). FSI and two HRIs observe in extreme
  ultraviolet passbands, dominated by coronal emission. Another HRI is
  designed for the hydrogen Lyman α radiation in the far UV, imaging the
  Chromosphere and the lower Transition Region. The current EUI design
  and some of its development challenges are highlighted. EUI profits from
  co-rotation phases, solar proximity and departure from the ecliptic. In
  synergy with the other S.O. payload, EUI probes the dynamics of the
  solar atmosphere, provides context data for all investigations and helps
  to link in-situ and remote-sensing observations. In short, it serves all
  four top-level goals of the mission. For these reasons, the EUI suite
  is keenly anticipated in the European scientific community and beyond.

Title: Modeling the Radiative Signatures of Turbulent Heating in
    Coronal Loops
Authors: Parenti, S.; Buchlin, E.; Cargill, P. J.; Galtier, S.; Vial,
   J. -C.
Bibcode: 2006ApJ...651.1219P
Altcode:
  The statistical properties of the radiative signature of a coronal loop
  subject to turbulent heating obtained from a three-dimensional (3D)
  magnetohydrodynamics (MHD) model are studied. The heating and cooling of
  a multistrand loop is modeled and synthetic spectra for Fe XII 195.12,
  Fe XV 284.163, and Fe XIX 1118.06 Å are calculated, covering a wide
  temperature range. The results show that the statistical properties
  of the thermal and radiative energies partially reflect those of the
  heating function in that power-law distributions are transmitted,
  but with very significant changes in the power-law indices. There is
  a strong dependence on the subloop geometry. Only high-temperature
  radiation (~10<SUP>7</SUP> K) preserves reasonably precise information
  on the heating function.

Title: The Helium Spectrum in Erupting Solar Prominences
Authors: Labrosse, N.; Vial, J. C.; Gouttebroze, P.
Bibcode: 2006IAUJD...3E..47L
Altcode: 2006astro.ph..9511L
  Even quiescent solar prominences may become active and sometimes
  erupt. These events are occasionally linked to coronal mass
  ejections. However we know very little about the plasma properties
  during the activation and eruption processes. We present the first
  computations of the helium line profiles emitted by an eruptive
  prominence. We follow the approach of Gontikakis et al. (1997) who
  computed the hydrogen spectrum in moving prominences. The prominence
  is modelled as a plane-parallel slab standing vertically above the
  solar surface and moving upward as a solid body. The helium spectrum is
  computed with a non local thermodynamic equilibrium radiative transfer
  code. The effect of Doppler dimming / brightening is investigated in
  the resonance lines of He I and He II formed in the EUV, as well as on
  the He I 10830 Å and He I 5876 Å lines. We focus on the line profile
  properties and the resulting integrated intensities. We also study the
  effect of frequency redistribution in the formation mechanisms of the
  resonance lines. It is shown that the helium lines are very sensitive
  to Doppler dimming effects. Together with the hydrogen lines they offer
  the possibility of a powerful diagnostic of the active and eruptive
  prominence plasma. We discuss the results in view of observations
  provided by SOHO, and by the upcoming EUS spectrometer on SOLAR-B.

Title: What We Have Learned about Prominences and Filaments from
    SOHO/SUMER and CDS Spectral Observations
Authors: Heinzel, P.; Schmieder, B.; Vial, J. -C.
Bibcode: 2006ESASP.617E..65H
Altcode: 2006soho...17E..65H
  No abstract at ADS

Title: Rotational Tomography of the Solar Corona-Calculation of the
    Electron Density and Temperature
Authors: Barbey, Nicolas; Auchère, Frédéric; Rodet, Thomas;
   Bocchialini, Karine; Vial, Jean-Claude
Bibcode: 2006ESASP.617E..82B
Altcode: 2006soho...17E..82B
  No abstract at ADS

Title: Looking for Signature of Coronal Heating in the Radiative
    Emission of a Coronal Loop
Authors: Parenti, S.; Buchlin, E.; Cargill, P. J.; Caltier, S.; Vial,
   J. -C.
Bibcode: 2006ESASP.617E.104P
Altcode: 2006soho...17E.104P
  No abstract at ADS

Title: The Pending Issue of the Solar Fine Structure of Prominences
Authors: Vial, J. -C.
Bibcode: 2006ESASP.617E.163V
Altcode: 2006soho...17E.163V
  No abstract at ADS

Title: The Helium Spectrum in Moving Solar Prominences
Authors: Labrosse, N.; Gouttebroze, P.; Vial, J. -C.
Bibcode: 2006ESASP.617E.134L
Altcode: 2006soho...17E.134L
  No abstract at ADS

Title: SMESE: a combined UV-IR-X-gamma solar mission
Authors: Millard, Anne A.; Auchere, Frederic; Fang, Cheng; Gan,
   Weiqun; Molodij, Guillaume; Prado, Jean-Yves; Rouesnel, Frederic;
   Semery, Alain; Trottet, Gerard; Vial, Jean-Claude; Yan, Yihua; Wu, Ji
Bibcode: 2006SPIE.6266E..0JM
Altcode: 2006SPIE.6266E..15M
  SMESE (SMall Explorer For the study of Solar Eruptions) is a
  Franco-Chinese microsatellite mission. The scientific objectives of
  SMESE are the study of coronal mass ejections and flares. Its payload
  consists of three instrument packages : LYOT, DESIR and HEBS. LYOT is
  composed of a Lyman α (121.6 nm) coronagraph, a Lyman α disk imager
  and a far UV disk imager. DESIR is an infrared telescope working at 35
  μm and 150 μm. HEBS is a high energy burst spectrometer working in
  X rays and γ rays covering the 10 keV to 600 MeV range. SMESE will
  be launched around 2011, providing a unique opportunity of detecting
  and understanding eruptions at the maximum activity phase of the solar
  cycle in a wide range of energies. The instrumentation on board SMESE
  is described in this paper.

Title: IFTSUV: an imaging Fourier transform spectrometer in UV for
    the next solar space missions
Authors: Millard, Anne A.; Lemaire, Philippe; Vial, Jean-Claude
Bibcode: 2006SPIE.6266E..2GM
Altcode: 2006SPIE.6266E..72M
  The study of the Sun in the UV spectral domain is essential for
  a better understanding of the physical processes taking place in
  the solar atmosphere. The main tools for this study are imagers
  and spectrometers. Nevertheless, the analysis of imagery data is
  rapidly limited unless spectral information is available, and the
  association of spectrometers and imagers is limited by the lack of
  coherence between the instruments. Therefore, the design of an imaging
  spectrometer in UV is a priority for solar physicists. In the far UV,
  only all reflective optical systems can be used thus an imaging Fourier
  transform spectrometer (IFTS) is the ideal candidate for the realization
  of such an instrument. The performances of an IFTS are given by the
  modulation efficiency. Theoretical study of performances and scientific
  objectives lead to technical and operating specifications. A mock-up of
  an IFTSUV has been built at IAS to validate the working principle. Its
  optical design and alignment are described in this paper. The first
  results are shown and discussed. Planned modifications of the design
  are also discussed.

Title: Plasma diagnostic of a solar prominence from hydrogen and
    helium resonance lines
Authors: Labrosse, N.; Vial, J. -C.; Gouttebroze, P.
Bibcode: 2006sf2a.conf..549L
Altcode: 2006astro.ph..9643L
  We present the first comparison of profiles of H et He resonance lines
  observed by SUMER with theoretical profiles computed with our non-LTE
  radiative transfer code. We use the HI Lyman β, HI Lyman ɛ, and He
  I λ 584 Å lines. Our code allows us to obtain the plasma parameters
  in prominences in conjunction with a multi-line, multi-element set
  of observations. The plasma temperature in the prominence core is ∼
  8600 K and the pressure is 0.03 dyn cm<SUP>-2</SUP>. The Lyβ line is
  formed in a higher temperature region (more than 11,000 K).

Title: A statistical study of SUMER spectral images: events,
    turbulence, and intermittency
Authors: Buchlin, E.; Vial, J. -C.; Lemaire, P.
Bibcode: 2006A&A...451.1091B
Altcode: 2005astro.ph.11042B
  We analyze a series of full-Sun observations performed with the
  SoHO/SUMER instrument between March and October 1996. Some parameters
  (radiance, shift and width) of the S vi 93.3 nm , S vi 94.4 nm ,
  and Ly \varepsilon line profiles were computed on board. Radiances
  and line-of-sight velocities in a large central region of the Sun
  are studied statistically: distributions of solar structures, field
  Fourier spectra and structure functions are obtained. The structures
  have distributions with power-law tails, the Fourier spectra of the
  radiance fields also display power laws, and the normalized structure
  functions of the radiance and velocity fields increase at small
  scales. These results support the idea of the existence of small
  scales, created by turbulence, and of intermittency of the observed
  fields. These properties may provide insight into the processes needed
  for heating the transition region, or, if confirmed in the corona,
  the corona itself. The difficulties encountered in this analysis,
  especially for the velocity data, underline the need for sensitive
  ultraviolet imaging spectrometers.

Title: New perspectives on prominences as observed by SOHO/SUMER
Authors: Schmieder, B.; Vial, J. -C.; Heinzel, P.
Bibcode: 2006sf2a.conf..563S
Altcode:
  We summarize the results of our prominence and filament studies
  based on extensive spectral observations with SOHO/SUMER and CDS
  instruments. During the past decade we have gathered several sets
  of UV and EUV spectral data, containing various emission lines of
  different species. Our main objective was to better understand the
  formation of hydrogen Lyman lines and continuum (using the results
  of complex non-LTE transfer simulations). However we have also
  analysed also UV and EUV lines formed under transition-region and
  coronal conditions. Some highlights of our studies are: reproduction
  of Lyman-line profiles with partial redistribution, understanding the
  role of prominence-corona interface in the formation of Lyman-line
  cores, establishing the effect of the magnetic-field orientation
  on the shape of Lyman lines, discovery of EUV filament extensions
  (invisible in the Hα line) and their explanation, reconstruction of
  a 3D topology of the filament using EUV coronal lines, temperature
  diagnostics based on measurements of the hydrogen Lyman continuum,
  proper explanation of a prominence darkening detected in coronal lines.

Title: A New Way to look at Observations with EGSO
Authors: Aboudarham, J.; Scholl, I.; Fuller, N.; Csillaghy, A.;
   Bentley, R. D.; Antonucci, E.; Ciminiera, L.; Finkelstein, A.; Ipson,
   S.; Messerotti, M.; Pike, D.; Vial, J. C.; Zharkova, V.
Bibcode: 2006IAUS..233..229A
Altcode:
  The European Grid of Solar Observations (EGSO) is a Solar virtual
  observatory (see Hill et al., 2002). It has been funded through the 5th
  Framework Program of the European Community. A dozen of laboratories,
  mixing Solar Physics and Information Technology, in Great Britain,
  France, Italy and Swiss have been involved in this project during
  3 years. A grid accessing several dozens of databases and archives
  scattered all around the world has been developped as well as a Solar
  Event Catalogue and a Solar Feature Catalogue. The original aspect
  of this work consists in the possibility not only to search through
  the characteristics of observations, but also search for available
  data corresponding to specific kinds of events. So it is now very
  important to be able to follow the Sun 24 hours a day in order to
  enrich the events database for future queries. More informations on
  EGSO, catalogues and user interface can be accessd through the web
  site: http://www.egso.org/

Title: European Grid of Solar Observations (EGSO)
Authors: Aboudarham, J.; Scholl, I.; Csillaghy, A.; Bentley, R. D.;
   Antonucci, E.; Ciminiera, L.; Finkelstein, A.; Ipson, S.; Messerotti,
   M.; Pike, D.; Vial, J. C.; Zharkova, V.
Bibcode: 2006ihy..conf...18A
Altcode:
  The EGSO project addresses the problem of combining heterogeneous
  data into a single "virtual" solar data resource. Wider access to
  other catalogues is enabled, including both pre-existing lists and
  new compilations generated using feature-recognition techniques on
  existing data. Scientists are also able to perform much richer data
  searches, based on solar events. Informations concerning EGSO can be
  found at http://www.egso.org/

Title: A brief introduction to SMESE mission
Authors: Wang, C.; Fang, C.; Gan, W.; Prado, J. -Y.; Trottet, G.;
   Vial, J. -C.; Yan, Y.; Auchere, F.; Chang, J.; Molodi, G.
Bibcode: 2006ilws.conf..211W
Altcode:
  Small Exploration for Solar Eruptions (SMESE) is a joint mission
  between France and China to investigate the two main types of eruption
  events on the Sun: Coronal Mass Ejections (CME) and solar flares,
  and their relationship. SMESE will provide a set of unprecedented
  and complementary measurements including Ly-alpha imager, Ly-alpha
  coronagraph, EUV imager, Detection of Solar Infra red radiation,
  Hard X-ray/gamma ray spectrometry. SMESE aims to study, among others,
  the CME triggering mechanism and its acceleration in the corona, the
  particle acceleration by CME and solar flare, the physical association
  of the CME and solar flare etc. SMESE will be launched in the next
  solar maximum between 2010-2012.

Title: Can we finally solve the problems of "Coronal Heating " and
    "Solar Wind Acceleration" in the Cosmic Vision era ?
Authors: Maksimovic, M.; Appourchaux, T.; Aulanier, G.; Chust, T.;
   Dudok de Wit, T.; Klein, K. L.; Krasnoselskikh, V.; Louarn, P.; Roux,
   A.; Vial, J. C.
Bibcode: 2006cosp...36.2999M
Altcode: 2006cosp.meet.2999M
  Since the discovery of the corona s million-degree temperature in the
  1940s and the supersonic solar wind in the early 1960s major efforts
  have been made to discover the physical mechanisms that could explain
  these two observations These efforts have led to a tremendous increase
  in our knowledge of our neighbour star the inner heliosphere and the
  Sun-Earth connections Unfortunately these efforts haven t allowed to
  provide a definitive answer to these questions Why such a situation On
  one hand the remote-sensing strategy has tried to probe the coronal
  properties by basically analysing the photons emitted or absorbed
  by the Sun s atmosphere With this regards limitations occur on both
  theoretical ground physics of the coupling between photons and plasma
  and experimental ground limited number of observables such as spectral
  lines or the hardly solvable problem of the line of sight integration
  On the other hand solar wind in-situ measurements have had access to
  the very detailed state of the local plasma properties full particles
  velocity distribution functions observations of the electromagnetic
  plasma fluctuations over a huge frequency range but at locations
  far from the corona and the solar wind acceleration regions Moreover
  it has been realized more recently that the magnetic field plays a
  fundamental role in shaping the low corona and channelling the energy
  inputs Unfortunately the measurement of the full magnetic vector in
  the corona is a very difficult enterprise and this lack of information
  hampers all on-going modelling efforts Given

Title: SMESE, a SMall Explorer for the Study of solar Eruptions
Authors: Vial, J. -C.; Auchère, F.; Chang, J.; Fang, C.; Gan, W. Q.;
   Molodij, G.; Prado, J. -Y.; Trottet, G.; Wang, C.; Yan, Y. H.
Bibcode: 2006cosp...36.3287V
Altcode: 2006cosp.meet.3287V
  The SMESE Small Explorer for the Study of solar Eruptions mission is
  a microsatellite proposed by France and China The payload of SMESE
  consists of three packages LYOT a suite of two UV and EUV imagers and
  a Lyman alpha coronagraph DESIR an Infra-Red Telescope working at 35
  and 150 mu and HEBS a High Energy Burst Spectrometer working in X-
  and gamma -rays The status of research on Coronal Mass Ejections and
  flares will be briefly recalled in the context of on-going missions
  such as SOHO TRACE and RHESSI The scientific objectives and the profile
  of the mission will be described With a launch around 2011 SMESE will
  provide a unique tool for detecting and understanding eruptions flares
  and coronal mass ejections in the maximum phase of activity when the
  Solar Dynamics Observatory SDO should still be operating

Title: SMESE: a Small Explorer for the Study of Solar Eruptions
Authors: Vial, J. -C.; Auchère, F.; Chang, J.; Fang, C.; Gan, W. Q.;
   Molodij, G.; Prado, J. -Y.; Trottet, G.; Wang, C.; Yan, Y. H.
Bibcode: 2006cosp...36.3294V
Altcode: 2006cosp.meet.3294V
  The SMESE Small Explorer for the Study of solar Eruptions mission is
  a microsatellite proposed by France and China The payload of SMESE
  consists of three packages LYOT a suite of two UV and EUV imagers and
  a Lyman alpha coronagraph DESIR an Infra-Red Telescope working at 35
  and 150 mu and HEBS a High Energy Burst Spectrometer working in X- and
  gamma -rays The status of research on Coronal Mass Ejections will be
  briefly recalled in the context of on-going missions such as SOHO TRACE
  and RHESSI The scientific objectives and the profile of the mission
  will be described With a launch around 2011 SMESE will provide a unique
  tool for detecting and understanding eruptions flares and coronal mass
  ejections in the maximum phase of activity and for the determination
  of the morphology of the low corona from where the solar wind originates

Title: Multiwavelength Analysis of an Active Region
Authors: Gontikakis, C.; Dara, H. C.; Zachariadis, Th. G.;
   Alissandrakis, C. E.; Nindos, A.; Vial, J. -C.; Tsiropoula, G.
Bibcode: 2006SoPh..233...57G
Altcode:
  We study active region NOAA 8541, observed with instruments on board
  SOHO, as well as with TRACE. The data set mainly covers the transition
  region and the low corona. In selected loops studied with SUMER on SOHO,
  the VIII 770 Å line is systematically redshifted. In order to estimate
  the plasma velocity, we combine the Doppler shifts with proper motions
  (TRACE) along these loops. In the case of an ejection, apparently
  caused by the emergence of a parasitic polarity, proper motions and
  Doppler shifts give consistent results for the velocity. A cooler loop,
  observed in the same active region with CDS, shows a unidirectional
  motion reminiscent of a siphon flow. The derived electron temperature
  and density along a large steady loop confirm that it cannot be
  described by hydrostatic models.

Title: Solar Hydrogen Lyman Contimuum Observations with Soho/sumer
Authors: Parenti, S.; Vial, J. -C.; Lemaire, P.
Bibcode: 2005ESASP.600E..93P
Altcode: 2005ESPM...11...93P; 2005dysu.confE..93P
  No abstract at ADS

Title: The Beleinos cornerstone: the Sun, the star close to Earth
Authors: Appourchaux, T.; Auchère, F.; Bocchialini, K.; Bonnet,
   R. M.; Gabriel, A.; Vial, J. -C.
Bibcode: 2005ESASP.588..389A
Altcode: 2005tssc.conf..389A
  No abstract at ADS

Title: Hydrogen Lyman α Profiles of AN Active Region Filament
    Obtained with SUMER on SOHO
Authors: Vial, J. -C.; Boutry, C.; Wilhelm, K.
Bibcode: 2005ESASP.600E.102V
Altcode: 2005ESPM...11..102V; 2005dysu.confE.102V
  No abstract at ADS

Title: Prominence atlas in the SUMER range 800-1250 Å. II. Line
    profile properties and ions identifications
Authors: Parenti, S.; Vial, J. -C.; Lemaire, P.
Bibcode: 2005A&A...443..679P
Altcode:
  We present a SOHO/SUMER spectral atlas in the 800-1250 Å range of
  a prominence and a Quiet Sun (QS) region observed in 1999. The atlas
  is produced for two separate areas of the prominence. The QS spectrum
  is used as a reference. This is the first prominence atlas obtained
  with high spectral resolution (≈0.044 Å). It provides information
  concerning more than 550 line profiles, in terms of position, total
  radiance, and FWHM, along with the ion identification. Forty new lines
  have been identified with respect to previously published spectra.

Title: A new relation between the central spectral solar H I Lyman
    α irradiance and the line irradiance measured by SUMER/SOHO during
    the cycle 23
Authors: Emerich, Claude; Lemaire, Philippe; Vial, Jean-Claude; Curdt,
   Werner; Schühle, Udo; Wilhelm, Klaus
Bibcode: 2005Icar..178..429E
Altcode:
  The spectral irradiance at the center of the solar H I Lyman α
  ( λ=121.5664nm, referred to as Lyα in this paper) line profile
  is the main excitation source responsible for the atomic hydrogen
  resonant scattering of cool material in our Solar System. It has
  therefore to be known with the best possible accuracy in order to
  model the various Lyα emissions taking place in planetary, cometary,
  and interplanetary environments. Since the only permanently monitored
  solar irradiance is the total one (i.e. integrated over the whole
  Lyα line profile), Vidal-Madjar [1975. Evolution of the solar Lyman
  alpha flux during four consecutive years. Solar Phys. 40, 69-86] using
  Orbiting Solar Observatory 5 (OSO-5) satellite Lyα data, established
  a semi-empirical formula allowing him to deduce the central spectral
  Lyα irradiance from the total one. This relation has been extensively
  used for three decades. But, at the low altitude of the OSO-5 orbit,
  the central part of the solar line profile was deeply absorbed by a
  large column of exospheric atomic hydrogen. Consequently, the spectral
  irradiance at the center of the line was obtained by a complex procedure
  confronting the observations with simulations of both the geocoronal
  absorption and the self-reversed shape of the solar Lyα profile. The
  SUMER spectrometer onboard SOHO positioned well outside the hydrogen
  geocorona, provided full-Sun Lyα profiles, not affected by such an
  absorption [Lemaire et al., 1998. Solar H I Lyman α full disk profile
  obtained with the SUMER/SOHO spectrometer. Astron. Astrophys. 334,
  1095-1098; 2002. Variation of the full Sun Hydrogen Lyman α and β
  profiles with the activity cycle. Proc. SOHO 11 Symposium, ESA SP-508,
  219-222; 2004. Variation of the full Sun Hydrogen Lyman profiles
  through solar cycle 23. COSPAR 2004 Meeting], making it—for the first
  time—possible to measure the spectral and total Lyα solar irradiances
  directly and simultaneously. A new relation between these two quantities
  is derived in an expression that is formally similar to the previous
  one, but with significantly different parameters. After having discussed
  the potential causes for such differences, it is suggested that the
  new relation should replace the old one for any future modeling of the
  numerous Lyα absorptions and emissions observed in the Solar System.

Title: Solar hydrogen-Lyman continuum observations with SOHO/SUMER
Authors: Parenti, S.; Lemaire, P.; Vial, J. -C.
Bibcode: 2005A&A...443..685P
Altcode:
  In this work we analyze the emission of the H Lyman continuum (HI
  LyC) in the Quiet Sun (QS) and a solar prominence, in order to derive
  information on the temperature of the emitting plasma. We used the
  spectral atlas obtained with SOHO/SUMER detector A in 1999 (Parenti
  et al. 2005, A&amp;A, 443, 679). The high spectral resolution of this
  instrument allows a good selection of the continuum, free from emission
  lines. However, in the HI LyC wavelength domain, the data suffer from
  large radiometric uncertainties, which lead us to use detector B as
  a reference. We obtained electron temperatures of 8281 K ± 280 K and
  7564 K ± 230 K in two separate parts of the prominence.

Title: Radiative Signatures of Coronal Loops Submitted to Turbulent
    Heating
Authors: Parenti, S.; Buchlin, E.; Galtier, S.; Vial, J. -C.
Bibcode: 2005ESASP.592..523P
Altcode: 2005soho...16E..97P; 2005ESASP.592E..97P
  No abstract at ADS

Title: Formation flyers applied to solar coronal observations:
    the ASPICS mission
Authors: Vives, S.; Lamy, P.; Auchere, F.; Vial, J. -C.; Koutchmy,
   S.; Arnaud, J.; Prado, J. -Y.; Frassetto, F.; Naletto, G.
Bibcode: 2005SPIE.5901..305V
Altcode:
  Classical externally-occulted coronagraphs are presently limited in
  their performances by the distance between the external occulter and
  the front objective. The diffraction fringe from the occulter and the
  vignetted pupil which degrades the spatial resolution prevent observing
  the inner corona inside typically 2-2.5 solar radii. Formation flyers
  open new perspectives and allow to conceive giant, externally-occulted
  coronagraphs using a two-component space system with the external
  occulter on one spacecraft and the optical instrument on the
  other spacecraft at approximately 100 m from the first one. ASPICS
  (Association de Satellites Pour l'Imagerie Coronographique Solaire)
  is a mission proposed to CNES in the framework of their demonstration
  program of formation flyers which is presently under study to exploit
  this technique for coronal observations. In the baseline concept,
  ASPICS includes three coronagraphs operating in three spectral
  domains: the visible continuum (K-corona brightness), the HI Lyman
  alpha emission line at 121.6 nm, and the HeII emission line at 30.4
  nm. Their unvignetted fields of view extend from 1.1 to 3.2 solar radii
  with a typical spatial resolution of 3 arcsec. In order to connect
  coronal activity to photospheric events, ASPICS further includes
  two disk imagers. The first one is devoted to the HI Lyman alpha
  emission line. The second one is a multi-channel instrument similar to
  SOHO/EIT and devoted to the HeII (30.4 nm), FeIX/X (17.1 nm) and FeXII
  (19.5 nm) emission lines. Two concepts of the space system are under
  consideration: a symmetric configuration where the disk imagers and
  the external occulter are on one spacecraft and the coronagraphs on
  the other, an asymmetric configuration where the external occulter is
  on one spacecraft and the scientific instruments are regrouped on the
  other one.

Title: EGSO - A maturing VO for Solar Physics
Authors: Bentley, R. D.; Scholl, I.; Csillaghy, A.; Aboudarham, J.;
   Antonucci, E.; Gurman, J.; Hill, F.; Pike, D.; Vial, J.; Zharkova, V.
Bibcode: 2005AGUSMSH43B..01B
Altcode:
  The European Grid of Solar Observations, EGSO, is a Grid test-bed
  funded under the Information Societies Thematic Priority of the European
  Commission's Fifth Framework Programme (FP5). In the case of EGSO, the
  application chosen was the use of Grid technology to establish a virtual
  observatory for solar physics, and the project addresses the generic
  problem of how to provide access to a distributed, heterogeneous data
  set for a scattered user community. In order to identify observations
  that match a user's search criteria, EGSO has been building an
  environment that will support complex searches. Because of the absence
  of the metadata needed to tie the heterogeneous data together, EGSO has
  placed emphasis on the provision of databases that can be accessed from
  the Internet through special providers. The provision of appropriate
  metadata is of extreme importance in establishing a virtual observatory,
  and the approach used can be adapted to facilitate the inclusion of
  any data, including non-solar data. We report on the capabilities of
  EGSO and discuss experience gained in creating the facility. We also
  discuss how EGSO has been working with other virtual observatories that
  support the solar, heliospheric and space plasma communities in order
  to try to achieve interoperability between the numerous data sets. We
  highlight what we consider are the most profitable ways of doing this.

Title: EUV imaging spectrometer for the Solar Orbiter mission
Authors: Millard, A. A.; Lemaire, P.; Vial, J. -C.
Bibcode: 2005AdSpR..36.1411M
Altcode:
  The results from missions such as Yohkoh, Trace or SOHO have advanced
  our understanding of the solar corona and heliosphere, but also have
  raised many new questions. Measurements at higher spatial resolution
  and cadence are needed, some regions such as the solar poles or
  the inner heliosphere remain unexplored. The Solar Orbiter mission
  addresses those questions. UV imaging spectrometers may be included
  in the remote sensing instruments package for this mission. Fourier
  transform spectrometry (FTS) is an ideal solution for imaging systems
  as there is no need to scan the region of interest with a slit to
  get a 2D map, and the spectral range covered is only limited by the
  bandpass of the filter and the maximum optical path difference that
  can be obtained. FTS systems also allow to make observations at high
  cadence (100 Hz). Working in the far UV (below 200 nm) requires the use
  of reflective only optical systems. A solution for such an instrument
  has been designed at IAS and a mock-up has been built in order to test
  and validate the working principle. The first results of the alignment
  phase are shown.

Title: Variation of the full Sun hydrogen Lyman profiles through
    solar cycle 23
Authors: Lemaire, P.; Emerich, C.; Vial, J. -C.; Curdt, W.; Schühle,
   U.; Wilhelm, K.
Bibcode: 2005AdSpR..35..384L
Altcode:
  The hydrogen Lyman (Lyα, 121.267 nm and Lyβ, 102.572 nm) lines are
  important contributors to the solar extreme ultra violet (EUV) flux
  which illuminates the upper Earth’s atmosphere. From high resolution
  spectral observations performed with the solar ultraviolet measurement
  of emitted radiations (SUMER) spectrometer on the Solar and Heliospheric
  Observatory (SOHO), the detailed profiles of these two lines have been
  obtained. Some insights into the variation of the shape of the profiles,
  sampled throughout the present solar cycle 23, are given and discussed.

Title: Solar Orbiter: A unique opportunity for investigating
    small-scale physical processes at work in the magnetic solar
    atmosphere
Authors: Vial, J. -C.
Bibcode: 2005AdSpR..36.1375V
Altcode:
  With knowledge gained from the recent ULYSSES, SOHO, TRACE and other
  missions, a great deal of progress has been made in our understanding
  of the structure and dynamics of the various regions of the solar
  atmosphere: e.g., transition region and "quiet" corona, coronal holes
  and active region loops. However, no clear conclusions can yet be
  drawn about the fundamental processes that determine the existence
  and the underlying physics of these regions, especially their
  observed high temperature and flows. The lack of adequate spatial
  resolution has limited the study of the continuum between cool/hot,
  source/sink, and magnetic/non-magnetic regions. We consider here,
  magnetic reconnection as an example of the basic processes that are
  most likely involved at many different scales in heating and particle
  acceleration. Starting with a possible mechanism for reconnection
  (flux emergence), we consider different remote-sensing signatures of
  reconnection: flows, field rearrangement, impulsive heating, particle
  acceleration, wave generation, propagation and dissipation. We discuss
  their small-scale properties derived from current measurements and ways
  to improve their observation. We also consider how remote sensing and
  in situ measurements could be coordinated. To demonstrate how these
  advances might be achieved, we discuss the potential for discoveries
  offered by the Solar Orbiter, resulting notably from its relatively
  high spatial resolution and its capacity to observe for a substantial
  time in co-rotation with the Sun.

Title: Coronal Magnetometry
Authors: Arnaud, J.; Faurobert, M.; Grec, G.; Vial, J. -C.
Bibcode: 2005EAS....14...95A
Altcode:
  Magnetic fields emerging in the solar atmosphere control the structure,
  dynamics and heating of the solar corona. Those fields remain
  essentially unattainable with present low corona instrumentation. We
  present the most direct way of magnetic field remote measurements
  in the internal corona, namely visible and infrared coronal emission
  lines magnetometry and we explain why Dome C should be investigated as
  a likely outstanding site for such observations. We develop a strategy
  towards a large aperture coronal magnetometer at Dome C in the context
  of the other main instrumental projects underway for solar physics.

Title: Modelling the Radiative Signatures of Turbulent Heating in
    Coronal Loops
Authors: Parenti, S.; Buchlin, E.; Galtier, S.; Vial, J. -C.
Bibcode: 2004ESASP.575..497P
Altcode: 2004soho...15..497P
  No abstract at ADS

Title: Solving Science Use Cases that relate to the Sun and
    Heliosphere with EGSO
Authors: Bentley, R. D.; Scholl, I.; Csillaghy, A.; Aboudarham,
   J.; Antonucci, E.; Gurman, J. B.; Hill, F.; Pike, D.; Vial, J.;
   Zharkova, V.
Bibcode: 2004AGUFMSH21B0415B
Altcode:
  The European Grid of Solar Observations (EGSO) is a grid testbed
  funded by the European Commission's Fifth Framework Programme under
  its Information Society Technologies (IST) thematic priority. The
  project started in 2002 and is designed to provide enhanced access to
  solar and related data around the world. The EGSO grid is composed
  of two main components, Roles to set up the grid and, catalogs and
  registries to allow roles to answer users queries. Catalogs are made
  of lists of observations, events and features (a new service provided
  by EGSO). Registries are built from these catalogs and organized in
  order to enhance search capabilities. EGSO is working closely with
  other virtual observatory (VO) projects in the solar physics and
  related domains. This includes the US Virtual Solar Observatory (VSO)
  and the Collaborative Sun-Earth Connector (CoSEC). More recently we
  have been working with the Virtual Space Plasma Observatory (VSPO) and
  have contact with the Virtual Heliospheric Observatory (VHO). Through
  discussions with future missions, and within the new IAU Working
  Group on ``International Data Access'' (Solar and Heliospheric),
  the VOs are studying ways of ensuring interoperability from the
  ``sun to dirt''. This type of integrated access will be particularly
  important to missions such as STEREO and Living Witha Star. In this
  paper we will report the current status of EGSO, demonstrate how the
  catalogs and registries model serves within the user interface, and
  show how the user can retrieve solar and heliospheric data to match
  a scientific query. EGSO Release 4 is now being Beta-tested by users
  and anyone interested should view the Web page detailing all the EGSO
  capabilities under http://www.egso.org/demo

Title: Simplified simulations of MHD
Authors: Buchlin, É.; Velli, Marco; Galtier, Sébastien; Vial,
   Jean-Claude
Bibcode: 2004sf2a.conf...91B
Altcode: 2004sf2a.confE.334B
  Because of the wide range of scales involved in MHD turbulence, a
  statistical approach may become necessary to keep a global view of this
  complex phenomenon. In particular, in the framework of the heating of
  the solar corona, the smallest events are not directly detectable by the
  current instruments but may be integrated to a statistical study. From
  the numerical point of view, the contradictory needs for computing speed
  and good description of MHD solutions may be addressed by simplified
  models, which keep the most possible of the complex and non-linear
  physics of the MHD equations but run sufficiently fast to produce
  statistics of fields, of structures, and of "events". We propose
  two such models which have been originally developed to represent
  coronal loops (with forcing and Alfvén wave reflection at the loop's
  foot-points), but which may be adapted to represent any region with
  a dominant large-scale magnetic field. The first model consists of a
  set of cellular automata, in which the non-linear terms of the MHD
  equations are modelled by a threshold dynamics on current density
  (Buchlin et al. A&amp;A, 2003). In the second model, the cellular
  automata are replaced by shell-models of MHD, so as to reach a greater
  range of wavenumbers and to model more realistically the non-linear
  couplings between modes at different scales. The results obtained
  with these models will be presented and consequences of this study
  for observational statistics and for theory of MHD turbulence will
  be discussed.

Title: Imagerie et spectrométrie dans l'UV pour les missions
    spatiales solaires LYOT et Solar Orbiter
Authors: Millard, A.; Lemaire, P.; Vial, J. -C.
Bibcode: 2004JPhy4.119..235M
Altcode:
  A l'horizon 2010, les missions spatiales solaires LYOT et Solar Orbiter
  permettront d'effectuer des observations du soleil (disque et couronne)
  dans l'UV à des résolutions spatiale et temporelle jamais réalisées
  auparavant. Pour atteindre ce but, les deux missions utiliseront en
  particulier des spectro-imageurs. La longueur d'onde de travail impose
  un schéma optique original uniquement en réflexion et utilisant des
  réseaux de diffraction. Le concept d'un tel instrument est décrit ici,
  et l'avancement de la maquette réalisée à l'IAS sont présentés.

Title: Prominence corona transition region plasma diagnostics from
    SOHO observations
Authors: Cirigliano, D.; Vial, J. -C.; Rovira, M.
Bibcode: 2004SoPh..223...95C
Altcode:
  New results concerning prominence observations and in particular
  the prominence-corona transition region (PCTR) are presented. In
  order to cover a temperature range from 2 × 10<SUP>4</SUP> to 7 ×
  10<SUP>5</SUP> K, several emission lines in many different ionization
  states were observed with SUMER and CDS on board SOHO. EM and DEM were
  measured through the whole PCTR. We compared the prominence DEM with
  the DEM from other solar structures (active region, coronal hole and the
  chromosphere-corona transition region (CCTR)). We notice a displacement
  of the prominence DEM minimum towards lower temperatures with respect
  to the minimum of the other structures. Electron density and pressure
  diagnostics have been made from the observed C III lines. Local
  electron density and pressure for T ∼ 7 × 10<SUP>4</SUP> K are
  respectively log N<SUB>e</SUB> = 9.30<SUB>−0.34</SUB><SUP>+0.30</SUP>
  and 0.0405<SUB>−0.014</SUB><SUP>+0.012</SUP>. Extrapolations over the
  entire PCTR temperature range are in good agreement with previous SOHO
  results (Madjarska et al., 1999). We also provide values of electron
  density and pressure in two different regions of the prominence (center
  and edge). The Doppler velocity in the PCTR shows a trend to increase
  with temperature (at least up to 30 km s -1 at T ∼ 7 × 10<SUP>4</SUP>
  K), an indication of important mass flows. A simple morphological model
  is proposed from density and motion diagnostics. If the prominence is
  taken as a magnetic flux tube, one can derive an opening of the field
  lines with increasing temperature. If the prominence is represented
  as a collection of threads, their number increases with temperature
  from 20 to 800. Derived filling factors can reach values as low as
  10<SUP>−3</SUP> for a layer thickness of the order of 5000 km. The
  variation of non-thermal velocities is determined for the first time,
  in the temperature range from 2 × 10<SUP>4</SUP> to 7 × 10<SUP>5</SUP>
  K. The quite clear similarity with the CCTR non-thermal velocities
  would indicate that heating mechanisms in the PCTR could be the same
  as in the CCTR (wave propagation, turbulence MHD).

Title: EUV imager and spectrometer for Lyot and Solar Orbiter space
    missions
Authors: Millard, Anne; Lemaire, Philippe; Vial, Jean-Claude
Bibcode: 2004ESASP.554..351M
Altcode: 2004icso.conf..351M
  In the 2010 horizon, solar space missions such as LYOT and Solar
  Orbiter will allow high cadence UV observations of the Sun at spatial
  and spectral resolution never obtained before. To reach these goals,
  the two missions could take advantage of spectro-imagers. A reflective
  only optical solution for such an instrument is described in this
  paper and the first results of the mock-up being built at IAS are shown.

Title: A New Relation between Central and Total Solar H I Lyman-α
    Irradiances, as measured by SOHO during Solar Cycle 23 (1996-2003)
Authors: Emerich, C.; Lemaire, P.; Vial, J. -C.; Curdt, W.; Schüle,
   U.; Wilhelm, K.
Bibcode: 2004AAS...204.9802E
Altcode: 2004BAAS...36..984E
  The spectral irradiance at the center of the solar H Ly-α line profile
  is the main excitation source responsible for the atomic hydrogen
  resonant scattering in cool material. It has therefore to be known
  with the best possible accuracy to model the H Ly-α emissions taking
  place in planetary, cometary and interplanetary environments. On
  the other hand, the only permanently monitored solar irradiance is
  the total one - either measured by near-Earth satellites, or deduced
  from its correlation with solar activity indexes. It is the reason why
  Vidal-Madjar (1975) using OSO-5 satellite H Ly-α data, established a
  semi-empirical formula allowing to deduce the central H Ly-α irradiance
  from the integrated one. This relation has been extensively used for
  three decades. In fact, at the low altitude of the OSO-5 orbit, the
  observed central part of the solar line profiles was deeply absorbed by
  a large column of exospheric atomic hydrogen. Consequently, the solar
  line center irradiances were not measured directly, but obtained by
  confronting the measurements with simulations of both the geocoronal
  absorption and the self-reversed shape of the central solar profile
  itself. <P />On the contrary, the SOHO/SUMER spectrometer orbiting well
  outside the H geocoronal envelope (at the L1 Sun-Earth Lagrange point),
  provided full Sun H Ly-α profiles, exempt from any central geocoronal
  absorption (Lemaire et al. (1998, 2002, 2004)). This has made it
  possible to directly measure the central H Ly-α solar irradiances
  as a function of the integrated ones, during eight years of Solar
  Cycle 23. The newly obtained relation confirms the general trend of
  the previous one, but it is characterized by significantly different
  coefficients. It will therefore provide new and more accurate inputs
  for the future modeling of the various Ly-α emissions occurring inside
  the Solar System.

Title: Flare observation of the Sun as a star by SUMER/SOHO in the
    hydrogen Lyman continuum
Authors: Lemaire, P.; Gouttebroze, P.; Vial, J. -C.; Curdt, W.;
   Schühle, U.; Wilhelm, K.
Bibcode: 2004A&A...418..737L
Altcode:
  During the execution of the programme ``Sun as a star'', while the
  SUMER (Solar Ultraviolet Emission of Emitted Radiation)/SOHO (SOlar and
  Heliospheric Observatory) slit was collecting the scattered radiation
  from the telescope mirror far away from the solar disk image, a class
  X5.3/3b flare erupted on the solar disk, on 25 August 2001. During
  the first phase of the flare a relative increase of a few percent was
  detected at the head of the hydrogen Lyman continuum. After correction
  from the instrumental parameters, the relative signal increase is 70%
  at the head of the Lyman continuum (910 Å), and 190% in the C II 904
  Å multiplet. Accounting for the area of the flare region, the local
  increase of the radiance of the Lyman continuum and of the C II lines
  is estimated to be a factor of several thousands. We compare this
  result with other solar observations and models. <P />Appendix A is
  only available in electronic form at http://www.edpsciences.org

Title: Prominence atlas in the SUMER range 800 1250 Å:
    I. Observations, data reduction and preliminary results
Authors: Parenti, S.; Vial, J. -C.; Lemaire, P.
Bibcode: 2004SoPh..220...61P
Altcode:
  The aim of this work is to build an EUV-UV spectral catalogue of a
  prominence. Here we focus on the preparatory work for the final result
  and we give an example of the results obtained. As a first step, we
  present the information needed for a full understanding of the results
  that will form the final entire catalogue. The data are composed of a
  full SUMER spectrum in the range 800-1250 Å of a prominence observed
  on 8 October 1999. A quiet-Sun area was also observed in the same
  spectral range in order to have a reference spectrum. Beside the
  standard corrections, we give details of the estimated stray light
  and the wavelength calibration of both datasets. We also present a
  short list of lines as an example of the results from the line-fitting
  procedure we applied to the data. For each line we give the measured
  position, the total intensity and the FWHM in the quiet Sun and at two
  different spatial positions in the prominence. With a final atlas of
  the prominence it will be possible to investigate several properties
  of the feature such as mass motion, differential emission measure,
  density, and elemental composition.

Title: Optical design of the Lyman alpha coronagraph for the LYOT
    microsatellite
Authors: Vives, Sebastien; Lamy, Philippe L.; Vial, Jean-Claude
Bibcode: 2004SPIE.5171..298V
Altcode:
  The LYOT (LYman Orbiting Telescope) solar mission (proposed for a CNES
  micro-satellite) is composed of a disk imager and a coronagraph, both
  working at Lyman-α (121.6 nm). The coronagraph is internally occulted
  and all-reflective with a field-of-view of 1.2 R up to 2.5 R and high
  spatial resolution (2 pixels) amounts to 5 arcsec. The optical design
  is driven by the requirement to use a superpolished spherical mirror
  to minimize the scattered light into the instrument. The LYOT mission
  will observe the Lyman-α corona at high cadence (1 image/5 minutes)
  over a period of two years.

Title: Variation of the full Sun hydrogen Lyman profiles through
    solar cycle 23
Authors: Lemaire, P.; Emerich, C.; Vial, J. -C.; Curdt, W.; Schühle,
   U.; Wilhelm, K.
Bibcode: 2004cosp...35..510L
Altcode: 2004cosp.meet..510L
  The hydrogen Lyman (121.267 nm and 102.572 nm) lines are important
  contributors to the solar EUV flux which illuminates the upper Earth's
  atmosphere. From high resolution spectral observations performed with
  the SUMER FUV-EUV spectrometer on SoHO, the detailed profiles of these
  two lines have been obtained. Some insights into the variation of the
  shape of the profiles, sampled throughout the present solar cycle 23,
  are shown and discussed.

Title: UV imager and spectrometer for LYOT and Solar Orbiter space
    missions
Authors: Millard, A.; Lemaire, P.; Vial, J. -C.
Bibcode: 2004cosp...35.1749M
Altcode: 2004cosp.meet.1749M
  The results from missions such as Yohkoh, Trace or SOHO have advanced
  our understanding of the solar corona and heliosphere, but also have
  raised many new questions. Measurements at higher spatial resolution and
  cadence are needed, some regions such as the solar poles or the inner
  heliosphere remain unexplored. Both LYOT and Solar Orbiter mission
  address those questions. UV imaging spectrometers may be included in
  the remote sensing instruments packages for these missions. Fourier
  transform spectrometry (FTS) is an ideal solution for imaging systems
  as there is no need to scan the region of interest with a slit to
  get a 2D map, and the spectral ranged covered is only limited by the
  bandpass of the filter and the maximum optical path difference that
  can be obtained. FTS systems also allows to make observations at high
  cadence (100 Hz). Working in the far UV (below 200 nm) requires the use
  of reflective only optical systems. A solution for such an instrument
  has been designed at IAS and a mock-up has been built in order to test
  and validate the working principle. The first results of the alignment
  phase are shown.

Title: Statistical Study of SOHO/SUMER Full-Sun Images
Authors: Buchlin, E.; Vial, J. -C.; Lemaire, P.; Galtier, S.
Bibcode: 2004ESASP.547..337B
Altcode: 2004soho...13..337B
  A series of full-Sun observations was performed with the SoHO/SUMER
  instrument between March and October 1996. Some moments of the
  S VI 93.3nm, S VI 94.4nm, and Ly line profiles were computed
  on-board. Intensities and line-of-sight velocities in a large central
  region of the Sun are studied statistically: histograms of intensities
  are computed, as well as histograms of total intensities of "events",
  and structure functions of the intensity field. Some statistics of
  velocities are the first to be obtained from observational data. The
  aim is to compare these statistics to results previously obtained with
  SoHO/EIT and by numerical simulations of MHD. Signatures of turbulent
  intermittency are also researched.

Title: Statistical properties of turbulence and intermittency in
    the solar corona observed in EUV
Authors: Buchlin, E.; Vial, J. -C.; Lemaire, P.
Bibcode: 2004cosp...35.3556B
Altcode: 2004cosp.meet.3556B
  Statistical properties of the fields observed on the Sun in EUV may
  help to understand turbulence in the solar corona and give clues to
  the processes involved in the heating of the corona to millions of
  degrees. In this study, we use a series of full-Sun images obtained
  in 1996 by the SUMER spectroheliograph on SoHO. Each observation
  consists of eight limb-to-limb raster scans in the lines Ly ɛ, S VI
  193.3 nm, and S VI 194.4 nm. Intensities, Doppler velocity shifts and
  line widths were computed on-board. A context spectrum was measured
  for each observation. Intensities and line-of-sight velocities data
  in a large central region of the Sun are then studied statistically:
  histograms of data values and of events, structure functions, and
  other statistics are computed. They are compared to results obtained
  by imaging instruments like SoHO/EIT and to numerical simulations of
  MHD. Structure functions of the velocity field reveal that turbulence
  in the corona may be intermittent.

Title: Integrated Access to Solar Data using EGSO
Authors: Bentley, R. D.; Csillaghy, A.; Scholl, I.; Vial, J. -C.;
   Aboudarham, J.; Antonucci, E.; Zharkova, V. V.; Pike, C. D.
Bibcode: 2004cosp...35.3935B
Altcode: 2004cosp.meet.3935B
  The European Grid of Solar Observations (EGSO) is a virtual observatory
  based on Grid technology that will change the way users analyze solar
  data. EGSO is funded under the IST (Information Society Technologies)
  thematic priority of the European Commission's Fifth Framework Programme
  (FP5). It started in March 2002 and will last for 3 years. The EGSO
  Consortium comprises eleven groups from five countries in Europe
  and the US, and is led by the Mullard Space Science Laboratory
  of University College London. The project aims to overcome one of
  the major hurdles in the analysis of solar data - finding what data
  are available and retrieving those that are needed. EGSO is creating
  layers of metadata catalogues that will for the first time provide the
  ability to select solar data based on phenomena and events. It is also
  integrating access to solar data by building a Grid including solar
  archives around the world. This combination of metadata and tools for
  selecting, processing and retrieving distributed and heterogeneous
  solar data, will radically change the way that data are distributed
  and analyzed. EGSO is collaborating closely with groups in the US who
  are working on similar virtual observatory projects for the solar,
  solar-terrestrial and heliospheric communities with the objective
  of providing integrated access to these data. In particular, strong
  synergies between the EGSO and CoSEC projects are producing innovative
  ways of accessing the data that will be deployed in both projects. Since
  the first release of EGSO in September 2003, members of the solar
  community have been involved in product testing. The constant testing
  and feedback allows us to continue to improve the quality and usability
  of the system. The capabilities of the latest release (R4) will be
  described, and the scientific problems that it addresses discussed.

Title: SOLAR ORBITER : a unique opportunity for investigating the
    physical processes at work in the magnetic solar atmosphere
Authors: Vial, J. -C.
Bibcode: 2004cosp...35.3808V
Altcode: 2004cosp.meet.3808V
  With recent ULYSSES, SOHO, TRACE (and other) missions, much progress has
  been made on the issues of structuring and dynamics in various regions
  of the solar atmosphere : transition region and ``quiet'' corona,
  coronal holes, active region loops. However, no clear conclusion could
  be drawn about the processes which determine their existence and their
  physics, especially their observed high temperatures or flows. For
  one reason, the lack of sufficient spatial resolution at all observed
  wavelengths has prevented to study the continuity between cool/hot,
  source/deposit, magnetic/non magnetic regions. For another reason, the
  study of the important regions of open magnetic field (mostly located
  at poles) has faced the severe drawback of observations performed from
  the ecliptic plane, except for (in-situ) ULYSSES measurements at a few
  A.U. We discuss the potential of discoveries offered by Solar Orbiter
  resulting notably from its spatial resolution performances and its
  capacity to fly above the ecliptic plane. We also stress how it is
  essential that remote sensing and in-situ measurements be coordinated.

Title: A search for turbulent wave heating and acceleration signatures
with SOHO/SUMER observations : Measurements of the widths of off-limb
    Iron lines
Authors: Dolla, L.; Lemaire, P.; Solomon, J.; Vial, J. -C.
Bibcode: 2003AIPC..679..351D
Altcode:
  The widths of coronal ions lines may contain important information
  about the energetics of the solar wind and corona. We present a
  method to measure these widths, taking into account the problems of
  instrumental stray light inherent to SoHO/SUMER. The Iron lines are
  interesting to set an upper limit on the ``unresolved'' velocity,
  that may be a signature of turbulent or wave motion in the corona.

Title: A solar cellular automata model issued from reduced MHD
Authors: Buchlin, E.; Aletti, V.; Galtier, S.; Velli, M.; Vial, J. -C.
Bibcode: 2003AIPC..679..335B
Altcode:
  A three-dimensional cellular automata (CA) model inspired by the reduced
  magnetohydrodynamic equations is presented to describe impulsive events
  generated along a coronal magnetic loop. It consists of a set of planes,
  distributed along the loop, between which the information propagates
  through Alfvén waves. Statistical properties in terms of power laws are
  obtained in agreement with SoHO observations of X-ray bright points of
  the quiet Sun. Physical meaning and limits of the model are discussed.

Title: A simplified numerical model of coronal energy dissipation
    based on reduced MHD
Authors: Buchlin, E.; Aletti, V.; Galtier, S.; Velli, M.; Einaudi,
   G.; Vial, J. -C.
Bibcode: 2003A&A...406.1061B
Altcode: 2002astro.ph.12444B
  A 3D model intermediate between cellular automata (CA) models and
  the reduced magnetohydrodynamic (RMHD) equations is presented to
  simulate solar impulsive events generated along a coronal magnetic
  loop. The model consists of a set of planes distributed along a
  magnetic loop between which the information propagates through Alfvén
  waves. Statistical properties in terms of power-laws for energies and
  durations of dissipative events are obtained, {and their} agreement
  with X-ray and UV flares observations {is discussed}. The existence
  of observational biases is {also} discussed.

Title: Distributions of Coronal Events: Simulations and Event
    Definitions
Authors: Buchlin, Éric; Galtier, Sébastien; Velli, Marco; Vial,
   Jean-Claude
Bibcode: 2003ANS...324..109B
Altcode: 2003ANS...324..P15B
  No abstract at ADS

Title: The solar high-resolution imager - coronagraph LYOT mission
Authors: Vial, Jean-Claude; Song, Xueyan; Lemaire, Philippe; Gabriel,
   Alan H.; Delaboudiniere, Jean-Pierre; Bocchialini, Karine; Koutchmy,
   Serge L.; Lamy, Philippe L.; Mercier, Raymond; Ravet, Marie Francoise;
   Auchere, Frederic
Bibcode: 2003SPIE.4853..479V
Altcode:
  The LYOT (LYman Orbiting Telescope) solar mission is proposed to
  be implemented on a micro-satellite of CNES (France) under phase A
  study. It includes two main instruments, which image the solar disk
  and the low corona up to 2.5 R<SUB>o</SUB> in the H I Lyman-α line
  at 121.6 nm. The spatial resolution is about 1” for the disk and
  2.5” for corona. It also carries an EIT-type telescope in the He II
  (30.4 nm) line. The coronagraph needs a super polished mirror at the
  entrance pupil to minimize the light scattering. Gratings and optical
  filters are used to select the Lyman-α wavelength. VUV cameras with
  2048×2048 pixels record solar images up to every 10 seconds. The
  satellite operates at a high telemetry rate (more then 100 kb/s,
  after onboard data compression). The envisaged orbits are either
  geostationary or heliosynchronous. Possible launch dates could be end
  of 2006 - beginning of 2007.

Title: Modelo semi-empírico de protuberancia solar a partir del
    diagnóstico de densidades
Authors: Cirigliano, D.; Vial, J. C.; Rovira, M.
Bibcode: 2003BAAA...46....7C
Altcode:
  A partir de la observación del espectro del quintuplete de C
  III alrededor de 1175 Å, se ha realizado el diagnóstico de la
  densidad y presión electrónica, basado en el cálculo del cociente
  de las intensidades observadas. Una vez establecida la densidad
  electrónica, y con el cálculo de las velocidades Doppler, hemos
  investigado el flujo de masa en la protuberancia en función de la
  temperatura. Estableciendo como hipótesis la conservación del número
  de partículas que ingresan y salen del cuerpo de la protuberancia, se
  investiga la variación del área de un tubo de flujo semi-empírico
  en función de la temperatura. A partir de dicho diagnóstico, se
  examina el comportamiento del radio del tubo magnético en función
  de la temperatura, los que dan cuenta de la abertura de las líneas
  de campo magnético que confinan el plasma y de la divergencia del
  campo magnético en diferentes alturas de la atmósfera solar.

Title: Some advances in the thermodynamic diagnostic of solar
    prominences
Authors: Vial, J. -C.
Bibcode: 2003EAS.....9..133V
Altcode:
  The aim of this paper is to present some recent advances in the
  diagnostic of solar prominences, with an emphasis put on the results
  obtained with SOHO through its six years of observations. We show the
  progress made since the Hvar Reference Model in the determination of
  basic thermodynamic parameters, especially in the Prominence-Corona
  Transtion Region (PCTR). We address the important contribution of
  ``prominence seismology" for determining e.g. density and magnetic
  field. We summarize the most recent comparisons between non-LTE
  modelling predictions and spectra of optically thick lines. Finally, we
  mention the most recent magnetic measurements which seem to challenge
  the historic Hanle measurements of Leroy ([CITE]) as summarized in
  Bommier et al. ([CITE]).

Title: Line profiles and intensity ratios in prominence models with
    a prominence to corona interface
Authors: Labrosse, N.; Gouttebroze, P.; Heinzel, P.; Vial, J. -C.
Bibcode: 2002ESASP.506..451L
Altcode: 2002svco.conf..451L; 2002ESPM...10..451L
  In this work we study the hydrogen, helium and calcium spectra
  emitted by a one-dimensional prominence model in magneto-hydrostatic
  equilibrium. The prominence slab consists of two parts: a cool
  core where the plasma is optically thick for some lines, and a
  prominence-to-corona transition region (PCTR) with a strong temperature
  gradient. The models are defined by 5 parameters: temperature, pressure,
  slab thickness, microturbulent velocity and altitude. We solve the NLTE
  radiative transfer equations for all optically thick transitions. We
  present line ratios between infrared, optical and EUV lines, as well
  as line profiles. We show that the presence of a PCTR, where both
  collisional and radiative excitations are important, affects H, He,
  and Ca populations and emergent lines in different manners.

Title: Quiet-Sun chromospheric network evolution
Authors: Lemaire, Philippe; Vial, J. -C.; Curdt, W.; Schühle, U.;
   Wilhelm, K.
Bibcode: 2002ESASP.505..477L
Altcode: 2002solm.conf..477L; 2002IAUCo.188..477L
  Using the SUMER/SOHO spectrometer we have observed the same quiet-Sun
  area during several days in a set of eight spectral lines of the
  transition region. Line intensity maps of the rastered areas are used to
  separate the interior of the supergranular cells from the network. Then,
  following the evolution of the supergranular pattern, we measure the
  variations of intensity and the Doppler shifts at several temperatures
  of formation of the transition region. We find that the overall flow
  velocity of the cell interior and the network generally decays within
  ten hours, which represents a significant part of the supergranular
  lifetime.

Title: Study of coronal loops using TRACE and SOHO
Authors: Gontikakis, C.; Dara, H. C.; Zachariadis, Th.; Nindos, A.;
   Alissandrakis, C.; Tsiropoula, G.; Vial, J. -C.
Bibcode: 2002ESASP.505..417G
Altcode: 2002solm.conf..417G; 2002IAUCo.188..417G
  We analysed coronal loops observed in many spectral lines from TRACE and
  SUMER, at the active region NOAA 8541, on May 15, 1999. For the loops,
  which are identified in a number of wavelengths, we try to combine
  the good temporal and spatial resolution of TRACE with the spectral
  information obtained by the SUMER rasters, in order to determine some
  physical parameters such as temperature, flow velocity and electron
  density. The morphology of the magnetic field of the loops is also
  approximated by a force-free extrapolation of the photospheric magnetic
  field, measured with MDI, and is compared to the loop morphology.

Title: Prediction of line intensity ratios in solar prominences
Authors: Gouttebroze, P.; Labrosse, N.; Heinzel, P.; Vial, J. -C.
Bibcode: 2002ESASP.505..421G
Altcode: 2002solm.conf..421G; 2002IAUCo.188..421G
  Solar prominences are made of relatively cool and dense plasma
  embedded in the solar corona, supported and structured by the magnetic
  field. Since this plasma is definitely out of LTE, the diagnosis
  of physical conditions in prominences needs the use of specific
  radiative transfer (RT) codes to predict the spectrum emitted by
  models and compare it to observations. For optically thin lines, the
  solution of RT equations in the transition itself is not required,
  but the emitted intensities depend, via the statistical equilibrium
  equations, on RT in other transitions which are optically thick. We
  use two different sets of models. The first one contains monolithic
  models defined by 5 parameters: temperature, pressure, thickness,
  microturbulent velocity and altitude above the solar surface. For
  each parameter, we assume a range of variation. For each model, the
  values of the 5 parameters are randomly chosen within the corresponding
  range of variation. The second set contains composite models made of
  multiple layers, in order to simulate the penetration of radiation into
  inhomogeneous prominences. We use NLTE radiative transfer codes to
  compute the intensities of the lines of hydrogen, helium and calcium
  emitted by each model. So, for any couple of lines, we may obtained
  their intensity ratio as a function of the 5 parameters. We discuss
  the behaviour of some of these intensity ratios as a function of the
  principal parameters and construct distribution diagrams, which are
  compared to different published observations.

Title: MHD waves in active region filament from SOHO-THEMIS joint
    observations
Authors: Régnier, S.; Solomon, J.; Vial, J. C.; Mein, P.
Bibcode: 2002ESASP.505..647R
Altcode: 2002IAUCo.188..647R; 2002solm.conf..647R
  The stability of solar filaments and their implications for eruptive
  events can be revealed by the existence of magnetohydrodynamic
  (MHD) waves. During the MEDOC campaign on May 2000, we performed
  joint observations involving SOHO and THEMIS instruments (CDS and
  MSDP respectively). We analyse the modes of oscillations for several
  spectral lines (Hα at 6563 Å, He I at 584 Å and Mg X at 609 Å):
  intermediate (6-40 min) and short (&lt; 5 min) periods are found and
  are discusssed in terms of MHD waves. The Hα time series (MSDP) in
  both line center intensity and line-of-sight Doppler shifts provide
  constraints on models of filament oscillations.

Title: Soho Contribution to Prominence Science
Authors: Patsourakos, Spiros; Vial, Jean-Claude
Bibcode: 2002SoPh..208..253P
Altcode:
  We present the main current issues concerning prominence studies. We
  recall the large range of plasma parameters found in prominences
  which makes the work of the MHD modeler more difficult. We also
  summarize the capabilities of the SOHO instrumentation. We present and
  discuss the most recent SOHO results concerning the determination of
  temperature, densities, and velocities. We put some emphasis on the
  different morphologies observed, the diagnostic capabilities of the
  Lyman lines profiles when accompanied by improved non-LTE modeling,
  and the information gathered from the first prominence oscillations
  measured from space. We also make an account of eruptive prominences. We
  finally discuss what could be done with present and future SOHO data
  to improve our understanding of prominences.

Title: A SUMER spectral atlas for prominences
Authors: Parenti, Susanna; Vial, J. -C.; Lemaire, P.
Bibcode: 2002ESASP.508..327P
Altcode: 2002soho...11..327P
  We present preliminary results of a study aimed at building a SUMER
  atlas for prominences. Using the atlas as reference, further studies
  can be addressed at deriving prominence properties, such as DEM
  distribution and anomalies in element abundances. Moreover, a comparison
  with previous atlas (e.g. Curdt et al., 2001) of other solar regions
  can be made. An extended prominence was observed with SUMER in the
  South-West solar limb in October 1999. A full spectrum was obtained
  in the waveband 790 - 1600 Å. After dealing with off-limb scattered
  light, the data are processed using multi-Gaussian fitting in order
  to derive the spectral properties of the observed structure. These
  properties are then also compared with those of the Quiet Sun area
  observed in the same wavelength range.

Title: Measurement of velocity fields in prominence plasma with
    SUMER/CDS on SOHO
Authors: Cirigliano, Daniela; Vial, Jean-Claude; Rovira, Marta
Bibcode: 2002ESASP.508..287C
Altcode: 2002soho...11..287C
  Disk and quiescent prominence observations have been obtained with the
  CDS (Coronal Diagnostic Spectrograph) and SUMER (Solar Ultraviolet
  Measurement of Emitted Radiation) instruments, on board SOHO. The
  purpose is to investigate the macroscopic velocities of several species
  in the prominence plasma as compared to the quiet Sun velocities. To
  calculate the solar disk velocities we have taken into account the
  bi-modal distribution of UV structures in the quiet Sun. The macroscopic
  velocities in prominences were computed from the Doppler shifts in
  every line spectrum, taking those in the solar disk as reference. We
  have obtained absolute values for the macroscopic velocities ranging
  from 5 km/s to 40 km/s. We have also attempted to separate the central
  core vs. the external border behaviours of the macroscopic velocities.

Title: Variation of the full Sun hydrogen Lyman α and β profiles
    with the activity cycle
Authors: Lemaire, Philippe; Emerich, C.; Vial, J. -C.; Curdt, W.;
   Schühle, U.; Wilhelm, K.
Bibcode: 2002ESASP.508..219L
Altcode: 2002soho...11..219L
  Full Sun hydrogen Lyman α and β profiles obtained through the
  activity cycle are needed to compare with stars, to understand the
  hydrogen distribution in the heliosphere and to evaluate the processes
  in the upper planetary atmospheres. Using the SUMER/SOHO telesocope
  scattered light properties, we have measured the Lyman α and β
  profiles at different epochs of the solar activity cycle. Here we
  report modifications in the intensity and the shape of the profiles.

Title: A Solar Cellular Automata Model Issued From Reduced MHD
Authors: Buchlin, E.; Aletti, V.; Galtier, S.; Velli, M.; Vial, J. -C.
Bibcode: 2002sf2a.conf..129B
Altcode:
  A three-dimensional cellular automata model inspired by the reduced
  magnetohydrodynamic equations is presented to describe impulsive events
  generated along a coronal magnetic loop. It consists of a set of planes,
  distributed along the loop, between which the information propagates
  through Alfven waves. Statistical properties in terms of power laws are
  obtained in agreement with SoHO observations of X-ray bright points of
  the quiet Sun. Physical meaning and limits of the model are discussed.

Title: Intermittent behavior in the transition region and the low
    corona of the quiet Sun
Authors: Patsourakos, S.; Vial, J. -C.
Bibcode: 2002A&A...385.1073P
Altcode:
  We present an analysis of light-curves obtained in the O IV and Ne
  VIII transition region and low corona lines, that were simultaneously
  recorded in a quiet Sun region by SUMER/SOHO. By using the flatness
  spectrum of the observed light-curves we searched for intermittency
  signatures. It was found that a significant proportion of points
  in the observed area exhibit clear indications of intermittency,
  irrespectively of their intrinsic intensity. Our findings give favor to
  an impulsively heated transition region and corona via intermittent-type
  MHD turbulence.

Title: Multiwavelength analysis of an active region observed with
    SOHO and TRACE
Authors: Dara, H. C.; Gontikakis, C.; Zachariadis, Th.; Tsiropoula,
   G.; Alissandrakis, C. E.; Vial, J. -C.
Bibcode: 2002ESASP.477...95D
Altcode: 2002scsw.conf...95D
  We study the solar active region NOAA 8541, observed on May 15, 1999,
  from 13:00 to 15:00 UT, with the instruments aboard SOHO (SUMER,
  CDS, MDI) and TRACE. The SOHO observations produced a set of raster
  scans of the region with a field of view of 159"×120" for SUMER and
  of 244"×240" for CDS. TRACE gave a sequence of high time resolution
  images for a much larger (510"×510") field of view, in several spectral
  passbands, while MDI gave the photospheric full disk longitudinal
  magnetic field. The data set mainly covers the transition region and
  the low corona. We have used the data to construct intensity, velocity
  and magnetic field maps of the region. The comparison of the intensity
  images in various wavelengths with the velocity images, as well as
  with the magnetic field, gives us information about the dynamical
  characteristics of the observed features and their relationship to
  the photospheric magnetic field.

Title: Relation between intensity and Dopplershifts in the quiet
    Sun transition region
Authors: Gontikakis, C.; Dara, H. C.; Zachariadis, Th.; Alissandrakis,
   C. E.; Vial, J. -C.
Bibcode: 2002ESASP.477..107G
Altcode: 2002scsw.conf..107G
  In this work we used CDS and SUMER (SOHO) observations of a quiet
  region (41°W 41°N) on the 28th of July 1996. The study of the
  histograms of the velocities corresponding to the network and the
  internetwork regions, shows that the network plasma is redshifted
  with respect to the internetwork one. The shifts in the histograms
  are small, but they are systematic for all lines. It should be
  mentioned that the internetwork is also statistically redshifted,
  with the exception of the He I line. In the low transition region the
  morphology in the intensity images is different from the morphology
  in the Dopplergrams. It seems that the network intensity structures
  correspond to more than one in the Dopplergrams, since the latter
  are quite smaller than the intensity structures. This was verified by
  calculating the average autocorrelation function for intensity images
  and Dopplergrams of spectral lines from SUMER and CDS. On the average,
  the FWHM of the autocorrelation function of the intensity images is
  two times larger than that of the corresponding Dopplergram ones.

Title: Cooling and evacuation of an active region loop complex
    observed with TRACE
Authors: Tsiropoula, G.; Gontikakis, C.; Dara, H. C.; Zachariadis,
   Th.; Alissandrakis, C.; Vial, J. -C.
Bibcode: 2002ESASP.477..179T
Altcode: 2002scsw.conf..179T
  We analyse the temporal variation of temperature and emission measure
  at the top of a coronal loop system observed with the Transition
  Region and Coronal Explorer (TRACE). Loops delineate regions of highly
  localized heating and are thus typically the focus of coronal heating
  theories. The analyzed data consist of observations in the 171 Å and
  195 Å passbands taken at a cadence of ~10 min obtained on May 15,
  1999 during an observing campaign. The temperature and emission measure
  diagnostic is based in the 171 Å / 195 Å filter-ratio technique. The
  loop system evacuates after the plasma at the top of the loops has
  cooled. Estimates of the timescales of energy losses by radiation
  and by conduction clearly suggest that the cooling is mainly due to
  radiation losses.

Title: Transition region quiet sun velocity field evolution
Authors: Lemaire, P.; Artzner, G.; Vial, J. -C.; Curdt, W.; Schühle,
   U.; Wilhelm, K.
Bibcode: 2002AdSpR..30..487L
Altcode:
  The UV/EUV SUMER spectrometer aboard SOHO can record profiles of lines
  emitted by elements at different stages of ionization corresponding
  to several temperatures within the transition region temperature
  range. During the solar cycle minimum in July 1996, we were able to
  observe the quiet Sun during five consecutive days. From the line
  positions we have determined the velocity fields and follow their time
  variations at different temperatures in the transition region. The line
  intensity maps are used to separate supergranular cells and network and
  they allow to compare the behaviors of the velocity fields evolution in
  the two structures. The results are critically analyzed and discussed.

Title: Observaciones del disco solar y de una protuberancia quiescente
    en radiación ultravioleta
Authors: Cirigliano, D.; Vial, J. -C.; Rovira, M.
Bibcode: 2002BAAA...45...18C
Altcode:
  Observaciones del disco solar y de una protuberancia quiescente en
  el rango de longitudes de onda ultravioleta fueron obtenidas con
  el instrumento CDS (Coronal Diagnostic Spectrograph) y SUMER (Solar
  Ultraviolet Measurements of emitted radiation) a bordo de la sonda
  SOHO. El propósito es investigar las velocidades macroscópicas de
  varias especies metálicas que se observan tanto en el disco solar como
  en el plasma de las protuberancias. Para calcular las velocidades del
  disco solar aplicamos una técnica mixta para modelar la distribución
  de estructuras en UV en el Sol quieto. Las velocidades macroscópicas
  en las protuberancias se calcularon a partir de los corrimientos
  Doppler en cada línea espectral y luego se tomaron las del disco
  solar como referencia. Obtuvimos valores absolutos para las velocidades
  macroscópicas entre 5 y 40 km/seg. También detectamos comportamientos
  diferentes en las velocidades de las protuberancias en el centro con
  respecto a los bordes.

Title: Relationships between CME's and prominences
Authors: Schmieder, B.; van Driel-Gesztelyi, L.; Aulanier, G.;
   Démoulin, P.; Thompson, B.; De Forest, C.; Wiik, J. E.; Saint Cyr,
   C.; Vial, J. C.
Bibcode: 2002AdSpR..29.1451S
Altcode:
  We have studied the erupting prominences which were associated with
  coronal mass ejections during a series of campaigns involving both
  spacecraft and ground-based observatories. The evolution of the
  physical conditions within the prominences was established from Hα
  and magnetic field observations. Particular attention ahs been paid
  to the presence of mixed amgnetic polarity in the filament channel,
  the evolution of the shear of the large-scale magnetic field, and
  the existence of multiple magnetic inversion lines. We conclude that
  reconnection of large-scale coronal magnetic fields is responsible
  for both the CME and filament eruption.

Title: Solar orbiter, a high-resolution mission to the sun and
    inner heliosphere
Authors: Marsch, E.; Antonucci, E.; Bochsler, P.; Bougeret, J. -L.;
   Fleck, B.; Harrison, R.; Langevin, Y.; Marsden, R.; Pace, O.; Schwenn,
   R.; Vial, J. -C.
Bibcode: 2002AdSpR..29.2027M
Altcode:
  The scientific rationale of the Solar Orbiter is to provide, at high
  spatial (35 km pixel size) and temporal resolution, observations of the
  solar atmosphere and unexplored inner heliosphere. Novel observations
  will be made in the almost heliosynchronous segments of the orbits at
  heliocentric distances near 45 R⊙ and out of the ecliptic plane at
  the highest heliographic latitudes of 30° - 38°. The Solar Orbiter
  will achieve its wide-ranging aims with a suite of sophisticated
  instruments through an innovative design of the orbit. The first
  near-Sun interplanetary measurements together with concurrent remote
  observations of the Sun will permit us to determine and understand,
  through correlative studies, the characteristics of the solar wind
  and energetic particles in close linkage with the plasma and radiation
  conditions in their source regions on the Sun. Over extended periods
  the Solar Orbiter will deliver the first images of the polar regions
  and the side of the Sun invisible from the Earth.

Title: Solar Orbiter: a high-resolution mission to the sun and
    inner heliosphere
Authors: Fleck, Bernhard; Marsch, E.; Antonucci, Ester; Bochsler,
   Peter A.; Bougeret, J. L.; Harrison, R.; Marsden, R. P.; Coradini,
   M.; Pace, Oscar; Schwenn, Rainer; Vial, Jean-Claude
Bibcode: 2001SPIE.4498....1F
Altcode:
  The key mission objective of the Solar Orbiter is to study the Sun
  from close-up (45 solar radii, or 0.21 AU) in an orbit tuned to solar
  rotation in order to examine the solar surface and the space above from
  a co-rotating vantage point at high spatial resolution. Solar Orbiter
  will also provide images of the Sun's polar regions from heliographic
  latitudes as high as 38 degrees. The strawman payload encompasses
  two instrument packages: Solar remote-sensing instruments: EUV
  full-sun and high resolution imager, high-resolution EUV spectrometer,
  high-resolution and full-sun visible light telescope and magnetograph,
  EUV and visible-light coronagraphs, radiometers. Heliospheric
  instruments: solar wind analyzer, radio and plasma wave analyzer,
  magnetometer, energetic particle detectors, interplanetary dust
  detector, neutral particle detector, solar neutron detector. To
  reach its novel orbit, Solar Orbiter will make use of low-thrust
  solar electric propulsion (SEP) interleaved by Earth and Venus gravity
  assists. Solar Orbiter was selected by ESA's Science Programme Committee
  (SPC) in October 2000 as a Flexi-mission, to be implemented after the
  BepiColombo cornerstone mission to Mercury before 2013. This paper
  summarizes the science to be addressed with the Solar Orbiter, followed
  by brief descriptions of the strawman payload, the mission profile,
  and the spacecraft and ground segment designs.

Title: Measuring Solar Abundances
Authors: von Steiger, R.; Vial, J. -C.; Bochsler, P.; Chaussidon, M.;
   Cohen, C. M. S.; Fleck, B.; Heber, V. S.; Holweger, H.; Issautier, K.;
   Lazarus, A. J.; Ogilvie, K. W.; Paquette, J. A.; Reisenfeld, D. B.;
   Teriaca, L.; Wilhelm, K.; Yusainee, S.; Laming, J. M.; Wiens, R. C.
Bibcode: 2001AIPC..598...13V
Altcode: 2001sgc..conf...13V
  This is the rapporteur paper of Working Group 2 on Measuring Solar
  Abundances. The working group presented and discussed the different
  observations and methods for obtaining the elemental and isotopic
  composition of the Sun, and critically reviewed their results and
  the accuracies thereof. Furthermore, a few important yet unanswered
  questions were identified, and the potential of future missions to
  provide answers was assessed. .

Title: The polar coronal holes and the fast solar wind: Some recent
    results
Authors: Patsourakos, S.; Habbal, S. -R.; Vial, J. -C.; Hu, Y. Q.
Bibcode: 2001AIPC..598..299P
Altcode: 2001sgc..conf..299P
  We report on recent results on the source regions of the fast solar
  wind: the Polar Coronal Holes (PCH). They concern a comparison
  between the effective temperatures for a large set of different ions
  obtained from observations in the inner corona of PCH and from a fast
  wind numerical model based on the ion-cyclotron resonant dissipation
  of high-frequency Alfvén waves. We also report on some preliminary
  results from our modeling concerning the Fe/O ratio in the inner corona
  in PCH. .

Title: Dopplershifts in the solar transition region
Authors: Gontikakis, C.; Dara, H. C.; Alissandrakis, C. E.;
   Zachariadis, Th. G.; Vial, J. -C.
Bibcode: 2001A&A...378..257G
Altcode:
  We study the dynamics of the quiet sun transition region, using
  observations obtained with the SOHO CDS/NIS and SUMER spectrographs. We
  examine the morphology of the network as a function of temperature and
  we compare the intensity features with those of the dopplergrams. The
  velocity distributions have a different behaviour for the bright
  features which outline the network and the dark ones, located in
  the internetwork. A redshift and a smaller standard deviation are
  observed for the bright feature distributions relative to the dark
  ones. It should be mentioned that the internetwork is also statistically
  redshifted, with the exception of the He I line. Velocity distributions
  from different lines are compared.

Title: Analysis of a UV Event in a Polar Coronal Hole
Authors: Patsourakos, Spiros; Vial, Jean-Claude
Bibcode: 2001SoPh..203...39P
Altcode:
  We present observations of a UV event which occurred in a polar coronal
  hole. They were obtained by SUMER on SOHO in several chromospheric and
  transition region spectral lines. Its birth site was about 50 arc sec
  inside the limb and in a network lane showing a net outflow before
  its initiation. The event had an extension of about 5 arc sec along
  the slit, a duration of about 3 min and was characterized by a large
  increase of intensity together with a significant line broadening
  with, however, downflows of about 50 km s<SUP>−1</SUP> being
  dominant. Proper motions with a velocity of about 10 km s<SUP>−1</SUP>
  were also observed. The event appeared at middle transition (O vi)
  temperatures and it simultaneously showed up in chromospheric (O i,
  Ly β) and low transition region (C ii) temperatures. We discuss this
  event in view of different scenarios to account for it. Our event could
  be a part of the large family of quiet-Sun explosive events observed
  by Ryutova and Tarbell (2000) taking place in polar coronal holes that
  are triggered by magnetic reconnection in the low solar atmosphere.

Title: Multi-wavelength analysis of a solar active region loop system
    with SOHO, TRACE and ground-based telescopes
Authors: Tsiropoula, G.; Gontikakis, C.; Dara, H. C.; Zachariadis,
   Th. G.; Alissandrakis, C.; Vial, J. -C.
Bibcode: 2001hell.confE..40T
Altcode:
  No abstract at ADS

Title: High-resolution EUV imaging and spectroscopy of the corona
Authors: Patsourakos, Spiros; Vial, J. -C.
Bibcode: 2001ESASP.493...13P
Altcode: 2001sefs.work...13P
  We present a set of imagers and spectrometer which have been proposed as
  a strawman payload on board the Solar Orbiter mission. The scientific
  requirements of the mission are put in the context of the main issues
  presently discussed in solar physics. The on-going successful space
  solar missions have evidenced a very fine structuring of the solar
  atmosphere and its role in various processes at work for coronal
  heating, wind acceleration, flaring activity, etc. This is especially
  true for magnetic reconnection which seems to proceed at many different
  scales. These results point at the need of observations substantially
  improving both the spatial resolution and the multi-temperature
  (multi-wavelength) coverage. Solar Orbiter offers a unique opportunity
  to analyze this fine structure (e.g. the internal structure of the
  thin loops observed by TRACE) in closed and open fields. It will allow
  for a diagnostic of regions such as the magnetic network which seems
  to play a major role in the wind acceleration, in conjunction with
  in-situ observations of the ejected plasma.

Title: Solar Orbiter EUV/UV wavelength selection and instrumentation -
    report of Payload Splinter Group 4
Authors: Harrison, R. A.; Vial, J. -C.
Bibcode: 2001ESASP.493..151H
Altcode: 2001sefs.work..151H
  We present here a summary of the discussions concerning the extreme
  ultraviolet (EUV) and ultraviolet (UV) wavelength selection and
  instrumentation for Solar Orbiter, held at the Tenerife meeting. These
  issues were assigned to Payload Splinter Group 4 and to the Wavelength
  Selection Working Group. Concerning the wavelength selection, a number
  of critical wavelength ranges were highlighted and discussed. Great
  emphasis was placed on good atmospheric coverage, from the chromosphere
  to the hottest coronal lines. A number of wavelength ranges were
  presented but the wide temperature range demands the inclusion of
  wavelengths longer than 912 Å as well as prime coronal lines in
  much shorter wavelength ranges, such as 170-250 Å. Regarding the
  instrumentation, the group agreed that Solar Orbiter should carry both
  imaging and spectroscopic capability in the EUV/UV and the two strawman
  instruments were presented and discussed. A number of alternatives
  were considered as were developments in technology, which could be of
  use for these instruments.

Title: Solar Orbiter, a high-resolution mission to the Sun and
    inner heliosphere
Authors: Marsch, E.; Harrison, R.; Pace, O.; Antonucci, E.; Bochsler,
   P.; Bougeret, J. -L.; Fleck, B.; Langevin, Y.; Marsden, R.; Schwenn,
   R.; Vial, J. -C.
Bibcode: 2001ESASP.493D..11M
Altcode: 2001sefs.workD..11M
  Solar Orbiter will provide, at very high spatial (35 km pixel size)
  and temporal resolution, novel observations of the solar atmosphere
  and unexplored inner heliosphere. It will achieve its wide-ranging
  scientific aims with a suite of sophisticated instruments through an
  innovative orbit design. Unprecedented observations will be made in
  the heliosynchronous segments of the orbits at heliocentric distances
  near 45 R<SUB>solar</SUB> and out of the ecliptic plane at the highest
  heliographic latitudes of 30° - 38°. The first near-Sun interplanetary
  measurements together with concurrent remote-sensing observations of
  the Sun and its corona will permit us to determine and understand,
  through correlative studies, the characteristics of the solar wind
  and energetic particles in close linkage with the plasma and radiation
  conditions in the source regions on the Sun. Solar Orbiter will deliver
  the first images of the polar regions and the far side of the Sun
  invisible from the Earth.

Title: Searching the source regions of the fast solar wind in polar
coronal holes: some recent SOHO/eclipse results and the potential
    of the Solar Orbiter
Authors: Patsourakos, Spiros; Vial, J. -C.
Bibcode: 2001ESASP.493..321P
Altcode: 2001sefs.work..321P
  No abstract at ADS

Title: Oscillations in an active region filament: Observations and
    comparison with MHD waves
Authors: Régnier, S.; Solomon, J.; Vial, J. C.
Bibcode: 2001A&A...376..292R
Altcode:
  During the MEDOC Campaign 4, on October 1999, observations of a
  solar active region filament were carried out by the SUMER/SoHO
  spectrometer. A time sequence of this filament has been obtained with
  a duration of 7 h 30 min and with a temporal resolution of 30 s. The
  Fourier analysis of the line-of-sight Doppler velocities measured in the
  584.33 Å HeI line allows us to detect oscillations in several ranges
  of periodicities (short periods: less than 5 min, intermediate periods:
  6-20 min, and long periods: greater than 40 min). From a theoretical
  point of view, we consider the possible modes of oscillations of an
  active region filament. Following \cite{joa93a}, we treat the filament
  as a plasma slab embedded in a uniform magnetic field inclined at an
  angle phi to the long axis of the slab. Solving the dispersion equations
  for Alfvén waves and magnetoacoustic waves, primary and secondary mode
  frequencies appear to be non-equidistant. For the comparison between the
  observed and calculated frequencies, we outline an identification method
  of the oscillation modes in the observed filament. This identification
  provides a diagnostic of the filament: the angle between the magnetic
  field and the long axis of the slab is estimated to be 18<SUP>deg</SUP>,
  and the magnetic field strength B (G) is proportional to the square
  root of the density rho<SUB>o</SUB> (cm<SUP>-3</SUP>) in the slab,
  B ~ 2.9 x 10<SUP>-5</SUP> sqrt {rho<SUB>o</SUB>}.

Title: On a mechanism of intensification of field-aligned currents
    at the solar chromosphere-quiescent prominence boundaries
Authors: Nenovski, P.; Dermendjiev, V. N.; Detchev, M.; Vial, J. -C.;
   Bocchialini, K.
Bibcode: 2001A&A...375.1065N
Altcode:
  Field-aligned electric currents (FAC) are assumed to support various
  prominence configurations and it is usually supposed that the
  quiescent prominence (QP) destabilisation can be initiated by some
  plasma instability. In this work we study another possibility of QP
  destabilisation connected with FAC changes. Such a destabilisation may
  occur when FAC flowing along a loop-shaped QP structure are intensified
  by bouncing surface MHD modes, presumably generated by motions in
  the photosphere under, or adjacent to, the QP. The MHD disturbances
  at the prominence ``feet'' propagate upwards as Alfven waves and
  surface modes. We study the possibility that the generated MHD modes,
  which carry FAC, bounce in the loop-shaped QP structure, provided that
  they undergo multiple reflection at the prominence feet. This is an
  interesting physical situation leading to intensification of FAC and
  promising to be another source of QP destabilisation.

Title: UVCS Observations of Velocity Shear at Streamer Boundaries
    in the Corona
Authors: Habbal, Shadia Rifai; Woo, Richard; Vial, Jean-Claude
Bibcode: 2001SSRv...97....5H
Altcode:
  Measurements of the intensities of the Ovi 1032 and 1037 Å spectral
  lines in the southern solar hemisphere, from 1.5 to 5 R_s, were made
  with the SOHO Ultraviolet Coronagraph Spectrometer (UVCS) in May
  2000 close to solar maximum. The ratio of the intensity of the two
  oxygen lines is used as a proxy for solar wind velocity in the inner
  corona. White light images of the corona taken with the SOHO/LASCO-C2
  during the same time period, and used to place the UVCS observations
  in the context of coronal structures, show streamers extending to
  high latitudes. The measured radial and azimuthal gradients of the
  intensity ratio reflect strong velocity shears in the corona with the
  slowest wind coinciding with the axis of streamers. Comparison of these
  results with ratios measured with UVCS during solar minimum indicates
  that the transition from fast to slow wind in the inner corona occurs
  within 20° of the axis of streamers at both phases of the solar cycle.

Title: Quelques réflexions sur les travaux en cours de la Commission
    "Système Solaire et Univers lointain" du Comité National
Authors: Vial, J. -C.
Bibcode: 2001sf2a.conf....7V
Altcode:
  No abstract at ADS

Title: UVCS Observations of Velocity Shear at Streamer Boundaries
    in the Corona
Authors: Habbal, Shadia Rifai; Woo, Richard; Vial, Jean-Claude
Bibcode: 2001SSRv...97....8H
Altcode:
  Measurements of the intensities of the O vi 1032and 1037 Å spectral
  lines in the southern solar hemisphere, from 1.5 to 5 R <SUB>s</SUB>,
  were made with the SOHO Ultraviolet Coronagraph Spectrometer (UVCS) in
  May 2000 close to solar maximum. The ratio of the intensity of the two
  oxygen lines is used as a proxy for solar wind velocity in the inner
  corona. White light images of the corona taken with the SOHO/LASCO-C2
  during the same time period, and used to place the UVCS observations
  in the context of coronal structures, show streamers extending to
  high latitudes. The measured radial and azimuthal gradients of the
  intensity ratio reflect strong velocity shears in the corona with the
  slowest wind coinciding with the axis of streamers. Comparison of these
  results with ratios measured with UVCS during solar minimum indicates
  that the transition from fast to slow wind in the inner corona occurs
  within 20° of the axis of streamers at both phases of the solar cycle.

Title: SOHO/SUMER observations and analysis of the hydrogen Lyman
    spectrum in solar prominences
Authors: Heinzel, P.; Schmieder, B.; Vial, J. -C.; Kotrč, P.
Bibcode: 2001A&A...370..281H
Altcode:
  The complete hydrogen Lyman spectrum in several prominences has been
  observed with the UV spectrometer SUMER on-board the SOHO, during
  the Joint Observing Programme 107, together with other space and
  ground-based observatories. Based on these observations, we are able to
  demonstrate, for the first time, that there exists a large variety of
  intensities and shapes of Lyman lines in different prominences and in
  various parts thereof. Therefore, no ``canonical'' Lyman spectrum can
  be considered for modelling purposes. However, we have identified at
  least two representative properties of the observed spectra: in one case
  (May 28, 1999 prominence) we detected high integrated intensities and
  no reversals in lines higher than Lalpha . Another prominence (June 2,
  1999) exhibited quite similar integrated intensities, but all lines have
  rather strongly reversed profiles. This behaviour cannot be explained in
  terms of standard isothermal-isobaric models and we thus consider more
  general models which are in pressure equilibrium with the magnetic field
  and which have significant prominence-corona transition region (PCTR)
  temperature gradients. This type of model, recently suggested by Anzer
  &amp; Heinzel (\cite{anhe99}), is capable of explaining strong emission
  profiles without reversal. Based on extended non-LTE computations,
  we suggest that quite different Lyman spectra mentioned above may
  correspond to two types of PCTRs, one seen along the magnetic-field
  lines (unreversed profiles) and the other one seen across the field
  lines (reversed profiles). Finally, we again confirm the importance
  of partial-redistribution (PRD) scattering processes for Lyman lines
  in prominences. However, our analysis of new SUMER data also points
  to a critical role of the PCTR in radiative transport in these lines.

Title: Dynamics of a Quiescent Solar Prominence Observed with the
    SUMER/SOHO Instrument
Authors: Bocchialini, K.; Costa, A.; Domenech, G.; Rovira, M.; Vial,
   J. C.; Wingfield, K.
Bibcode: 2001SoPh..199..133B
Altcode:
  We present the results obtained from analyzing SUMER/SOHO observational
  data of a quiescent solar prominence. The studied prominence is made of
  complex structures. From the 1-hr data set, we derive characteristic
  frequencies in terms of intensity and velocity oscillations, as
  measured in 4 transition-region lines. The presence of different types
  of frequencies is detected: chromospheric oscillations and intermediate
  periods (6 min to 12 min). This result suggests that these oscillations
  are transmitted by the magnetic fields from the chromosphere to the
  transition region.

Title: SUMER/SOHO Observations of Long Period Oscillations in an
    Active Region Filament
Authors: Régnier, S.; Solomon, J.; Vial, J. C.
Bibcode: 2001IAUS..203..307R
Altcode:
  During the MEDOC campaign #4 (October 1999), we observed an active
  region filament with the SUMER/SoHO spectrometer. After a global
  description of the active region NOAA 8725 with several instruments
  on board SoHO, we present a Fourier analysis of SUMER long time
  observations. This analysis allows to detect oscillations in several
  ranges of periodicities : 6-20 min, 30-40 min, and 55-150 min. We
  discuss these periodicities in terms of Alfvén and magnetoacoustic
  waves obtained in filament models developped by different authors. New
  MEDOC campaign (May 2000) coordinated with THEMIS (Tenerife) observatory
  should allow to examine the problem more closely.

Title: Solar Orbiter, a High-Resolution Mission to the Sun and
    Inner Heliosphere
Authors: Marsch, E.; Antonucci, E.; Bochsler, P.; Bougeret, J. -L.;
   Fleck, B.; Harrison, R.; Marsden, R.; Schwenn, R.; Vial, J. -C.
Bibcode: 2001IAUS..203..565M
Altcode:
  The scientific rationale of the Solar Orbiter (SO) is to provide,
  at high spatial and temporal resolution, observations of the solar
  atmosphere and unexplored inner heliosphere. The most interesting and
  novel observations will be made in the almost heliosynchronous segments
  of the orbits at heliocentric distances near 45 R<SUB>odot</SUB> and
  out-of-ecliptic at the highest heliographic latitudes of 38 degrees. The
  SO will achieve its many and varied aims with a suite of small and
  innovative instruments through a clever choice of orbits. The first
  near-Sun interplanetary measurements together with concurrent remote
  observations of the Sun will permit us to determine and understand,
  through correlative studies, the characteristics of the solar wind and
  energetic particles in close linkage with the plasma and radiation
  conditions in their source regions on the Sun. The SO will, during
  the high-latitude orbital passes, provide the first observations of
  the Sun's polar regions as seen from outside the ecliptic and also
  measure the magnetic field at the poles.

Title: Plasma Parameters of a Prominence Observed on October 16/17
    1999 by SUMER and CDS/SOHO
Authors: Madjarska, M. S.; Vial, J. -C.; Boccialini, K.; Dermendijiev,
   V. N.
Bibcode: 2001IAUS..203..410M
Altcode:
  The aim of our study was to confirm and enrich the results obtained
  so far on dynamics and diagnostics of solar prominences. A prominence
  observed on October 16/17, 1999 during MEDOC campaign # 4 in the frame
  of the updated joint observing programme 09 was studied. The main
  prominence plasma parameters like temperature and density were derived
  as well as their changes during 8 hours of observations. The relative
  line-of-sight velocities were obtained in the cool plasma material
  (SUMER, Si IV, 8 10<SUP>4</SUP> K) and prominence-corona transition
  region (SUMER, O IV, 2 10<SUP>5</SUP> K). Velocity and line width maps
  in both CDS He I 584 Å and O V 629.73 Å were derived. A study of the
  blend of O IV 1404.81 Å by Si IV 1404.77 Å and the second order line
  O III 702.31 Å was made.

Title: DEM Study of Selected Quiet Sun Regions
Authors: Gontikakis, C.; Landi, E.; Dara, H. C.; Alissandrakis, C. E.;
   Vial, J. -C.
Bibcode: 2001IAUS..203..390G
Altcode:
  In the present work EUV spectra of quiet Sun regions, observed with
  the Coronal Diagnostic Spectometer (CDS), are analysed in order to
  determine the Differential Emission Measure (DEM) of selected areas
  of the field of view. In particular, we study the differences between
  the DEM curves of the quiet Sun cell center areas, network areas and
  cell-network boundaries. The results are discussed in the light of
  theoretical models for the solar upper atmospheres.

Title: Oscillations Observed in Intensity and Velocity for a
    Quienscent Prominence
Authors: Bocchialini, K.; Costa, A.; Domenech, G.; Rovira, M.; Vial,
   J. -C.
Bibcode: 2001IAUS..203..419B
Altcode:
  We present the results obtained from analyzing SUMER/SOHO observation
  data of a solar prominence. The studied prominence can be characterized
  as having a complex structure. From the 1 hour data set, we derived
  characteristic frequencies in terms of intensity and velocity
  oscillations, for 4 transition region lines. The homogenity in the
  characteristic frequencies suggests the engagemente of coronal
  oscillations with the chromospheric structure. The presence of
  different types of frequencies is detected: chromospheric oscillations,
  intermediate periods (6min to 12min) and also long periods (25min to
  51min). This result suggests that these oscillations are transmitted
  by the magnetic fields.

Title: Microscale Structures on the Quiet Sun and Coronal Heating
Authors: Aletti, V.; Velli, M.; Bocchialini, K.; Einaudi, G.;
   Georgoulis, M.; Vial, J. -C.
Bibcode: 2000ApJ...544..550A
Altcode:
  We present some results concerning transient brightenings on the quiet
  Sun, based on data from the Extreme-Ultraviolet Imaging Telescope on
  board the Solar and Heliospheric Observatory. Histograms of intensity
  are found to be well fitted by χ<SUP>2</SUP> distributions for
  small values of the intensity, while at high intensities power-law
  distributions are always observed. Also, the emission presents the
  same statistical properties when the resolution is downgraded by local
  averaging; i.e., it appears to be self-similar down to the resolution
  scale of the instruments. These properties are characteristic of
  the emission from a forced turbulent system whose dissipation scale
  is much smaller than the pixel dimension. On the basis of the data
  presented as well as other published results and our present theoretical
  understanding of MHD turbulence, we discuss the realism of the nanoflare
  scenario of coronal heating.

Title: Outflow velocity of interplume regions at the base of Polar
    Coronal Holes
Authors: Patsourakos, S.; Vial, J. -C.
Bibcode: 2000A&A...359L...1P
Altcode:
  We report on SUMER/SOHO observations at 1.05 R<SUB>sun</SUB> of a well
  identified interplume region in a South Pole Coronal Hole. Combination
  of Doppler shifts and Doppler dimming measurements allowed to
  determine, for the first time, the total wind outflow velocity (~ 67 km
  s<SUP>-1</SUP>) at this height. Our calculations of the outflow velocity
  benefit from co-spatial and almost co-temporal observations. This large
  outflow velocity is a strong argument in favour of the interplumes
  being the main source of the fast solar wind. We find that the mass
  flux density through the observed interplume is 4.8 10<SUP>-10</SUP>
  g cm<SUP>-2</SUP>s<SUP>-1</SUP> which yields 10<SUP>-15</SUP> g
  cm<SUP>-2</SUP>s<SUP>-1</SUP> at 1 AU with an expansion factor of 11.

Title: Multi-wavelength study of the slow ``disparition brusque"
    of a filament observed with SOHO
Authors: Schmieder, B.; Delannée, C.; Yong, Deng Yuan; Vial, J. C.;
   Madjarska, M.
Bibcode: 2000A&A...358..728S
Altcode:
  A mid-latitude filament was observed before and after its eruption with
  SOHO (EIT, SUMER, CDS and LASCO) and with ground based observatories
  (Meudon and Pic du Midi) in the context of a coordinated MEDOC
  campaign in Orsay. The eruption was followed by a large Coronal
  Mass Ejection well observed by LASCO. Few hours before its eruption,
  the filament is partially heated (as seen in 195 Ä with EIT). The
  physical conditions of the filament before its eruption have been
  investigated by spectroscopic analysis of SUMER (the Lyman series L4 to
  L9) and of CDS combined with the Multi-channel Subtractive Double Pass
  Spectrograph (MSDP) spectra of Hα . Five hours before the eruption,
  large broadenings of chromospheric and transition region lines (CDS)
  were observed in the main body of the filament suggesting strong
  turbulence as well as opposite Dopplershifts on each side of the
  filament (Hα and He I) which could be interpreted as twist motions. The
  optical thickness of the filament is rather large. During the eruption
  the twist is largely developed as observed in 304 Ä. The Doppler
  shifts of the filament estimated from Lyman lines are in good agreement
  with the velocity of the front edge of the CME bright loop. We notice
  that both, the filament and the bright loop, are deviated towards the
  equator. This implies that they belong to the same global expansion
  event constrained to remain in the equatorial streamer. An X-ray bright
  point observed close to a filament footpoint could be the signature of
  reconnection process linked to the destabilization of the filament. It
  is interpreted in the framework of new MHD modeling of lateral filament
  footpoints (Aulanier &amp; Démoulin 1998).

Title: Solar Orbiter --- A High Resolution Mission to the Sun and
    Inner Heliosphere
Authors: Fleck, B.; Marsch, E.; Schwenn, R.; Antonucci, E.; Bochsler,
   P.; Bougeret, J. -L.; Harrison, R. A.; Marsden, R.; Vial, J. -C.
Bibcode: 2000SPD....31.0296F
Altcode: 2000BAAS...32..828F
  The scientific rationale of the Solar Orbiter (SO) is to provide,
  at high spatial and temporal resolution, observations of the solar
  atmosphere and unexplored inner heliosphere. The most interesting and
  novel observations will be made in the almost heliosynchronous segments
  of the orbits at heliocentric distances near 45 R<SUB>sun</SUB> and
  out-of-ecliptic at heliographic latitudes of up to 38<SUP>o</SUP>. By
  going to 45 R<SUB>sun</SUB> the SO will allow remote sensing of the
  solar atmosphere with unprecedented spatial resolution, and the almost
  heliosynchronous orbit segments will permit us to disentangle spatial
  and temporal variations in the solar wind in close linkage with the
  plasma and radiation conditions in the source regions of the Sun. The
  strawman payload encompasses two instrument packages: Heliospheric
  Instruments --- high-res visible light telescope and magnetograph
  (&lt;40 km), high-res X-ray/EUV imager (&lt;30 km), high-res EUV
  spectrometer (&lt;100 km), EUV and visible-light coronagraphs, solar
  neutron and γ -ray detectors, radiometers. Heliospheric Instruments
  --- solar wind analyzer, magnetometer, energetic particle detectors, IP
  dust detector, plasma wave analyser, radio experiment, neutral particle
  detector. Using solar electric propulsion (SEP) in conjunction with
  multiple planet swing-by manoeuvres, it will take SO two years to reach
  a perihelion of 45 R<SUB>sun</SUB> at an orbital period of 149 days,
  with an inclination ranging from 6.7<SUP>o</SUP> to 23.4<SUP>o</SUP>
  w.r.t. the ecliptic. During an extended mission phase of about 2
  years the inclination will increase to 31.7<SUP>o</SUP>, leading to
  a maximum heliographic latitude of 38.3<SUP>o</SUP>. The SO was one
  of the about 40 responses to the Call for Proposals for the next two
  "flexi-missions" (F2 and F3) within ESA's Scientific Programme. At
  its meeting on 1 March 2000, ESA's Space Science Advisory Committee
  recommended the Solar Orbiter among 5 other proposals for an assessment
  study. Launch is expected by the end of the decade.

Title: 3-D Magnetic Configurations for Filaments and Flares: The
    Role of ``Magnetic Dips'' and ``Bald Patches''
Authors: Aulanier, G.; Schmieder, B.; van Driel-Gesztelyi, L.; Kucera,
   T.; Démoulin, P.; Fang, C.; Mein, N.; Vial, J. -C.; Mein, P.; Tang,
   Y. H.; Deforest, C.
Bibcode: 2000AdSpR..26..485A
Altcode:
  The 3-D magnetic configuration of a filament and of a low energy
  flare is reconstructed, using linear mag- netohydrostatic (lmhs)
  extrapolations. In both cases, we find observational signatures
  of energy release at the locations of computed ``bald patches''
  separatrices, characterised by field lines which are tangent to
  the photosphere.The filament was observed on Sept. 25, 1996, in Hα
  with the MSDP on the German VTT, Tenerife, as well as in Si IV with
  SOHO/SUMER. It is modeled as a twisted flux-tube deformed by the
  magnetic polarities observed with SOHO/MDI. The shape and location of
  the computed dipped field lines are in good agreement with the shape of
  the filament and its feet observed in Hα. Some ``bald patches'' (BPs)
  are present where the distribution of dips reaches the photosphere. We
  show that some of the large scale field lines rooted in BPs can be
  related to bright fine structures in Si IV. We propose that the plasma
  there is heated by ohmic dissipation from the currents expected to be
  present along the BP separatrices.The flare was observed on May 18,
  1994, in soft X-rays with Yohkoh/SXT, and in Hα at Mitaka (Japan). The
  magnetic field is directly extrapolated from a photospheric magnetogram
  from Kitt Peak Observatory. The intersections with the photosphere of
  the computed separatrices match well the bright Hα ribbons. The later
  are associated to three BPs, with overlaying dipped field lines. We
  show that enhanced densities are present in these dips, which can be
  correlated with dark Hα fibrils.Both cases show the importance of
  dipped field lines and BPs in the solar atmosphere. Energy release
  via ohmic dissipation as well as reconnection along BP separatrices
  is proposed to provide heating observed as UV brightenings in filament
  channels and even as small flares

Title: Transport and Energy Conversion in the Heliosphere
Authors: Rozelot, J. P.; Klein, L.; Vial, J. -C.
Bibcode: 2000LNP...553.....R
Altcode: 2000tech.conf.....R
  No abstract at ADS

Title: Solar Prominences Observed by Soho (SUMER, CDS, EIT) and
    Ground-Based Observatories (GBO)
Authors: Heinzel, P.; Schmieder, B.; Vial, J. C.; Rudawy, P.
Bibcode: 2000AdSpR..25.1777H
Altcode:
  We present two sets of prominence observations in higher lines
  of the hydrogen Lyman series (from Lδ to L-9), together with
  some other UV lines. These data have been obtained by the Solar
  Ultraviolet Measurements of Emitted Radiation (SUMER) onboard the
  SOHO satellite in June 1997. Coordinated observations were also taken
  by other SOHO instruments: Coronal Diagnostic Spectrometer (CDS) and
  Extreme-Ultraviolet Imaging Telescope(EIT) and with the coronagraph
  of the Wroclaw University Observatory at Bialkóv, the spectrograph
  of the Ondřejov Observatory. We demonstrate the basic characteristics
  of the calibrated line profiles and compare them with the theoretical
  profiles computed from isothermal-isobaric models

Title: Future Diamond UV Imagers For Solar Physics
Authors: Hochedez, J. -F.; Verwichte, E.; Bergonzo, P.; Guizard, B.;
   Mer, C.; Tromson, D.; Sacchi, M.; Dhez, P.; Hainaut, O.; Lemaire,
   P.; Vial, J. -C.
Bibcode: 2000PSSAR.181..141H
Altcode:
  No abstract at ADS

Title: Modelling of Helium Spectrum in Solar Prominences
Authors: Labrosse, N.; Gouttebroze, P.; Vial, J. -C.
Bibcode: 1999ESASP.448..503L
Altcode: 1999mfsp.conf..503L; 1999ESPM....9..503L
  No abstract at ADS

Title: Observational Signatures of Microscale Heating
Authors: Bocchialini, K.; Aletti, V.; Vial, J. -C.; Lemaire, P.
Bibcode: 1999ESASP.448..539B
Altcode: 1999ESPM....9..539B; 1999mfsp.conf..539B
  No abstract at ADS

Title: Magnetic and Dynamic Evolution of an Active Region
Authors: Régnier, S.; Solomon, J.; Vial, J. C.; Amari, T.; Mickey, D.
Bibcode: 1999ESASP.448..519R
Altcode: 1999mfsp.conf..519R; 1999ESPM....9..519R
  No abstract at ADS

Title: Is Flaring Activity present in the Chromospheric Network ?
Authors: Cauzzi, G.; Falchi, A.; Falciani, R.; Vial, J. C.
Bibcode: 1999ESASP.448..685C
Altcode: 1999mfsp.conf..685C; 1999ESPM....9..685C
  Microflares occurring at coronal levels are one of the mechanisms
  proposed for the heating and dynamics of the chromospheric
  network. During a SOHO coordinated campaign, we acquired a set
  of chromospheric and transition region data, at high temporal and
  spatial resolution, that are suitable for such a research. We describe
  the characteristics of network points at several heights in the
  atmosphere. We look for the presence of signatures typical of flares,
  albeit at much smaller scales. Only one, of the 11 network points
  analyzed over 1 hr of observations, displays several episodes of red
  asymmetry in the H_α wings. These asymmetries can be interpreted
  as downward motions induced by the sudden compression of the lower
  atmosphere caused by either a particle beam or a conduction front. The
  analysis hence suggests that microflaring events in network points
  have a low occurrence probability, or that their energy flux is still
  below our observational capabilities.

Title: Structure and Dynamics in the Transition Region
Authors: Gontikakis, C. P.; Dara, H. C.; Alissandrakis, C. E.;
   Zachariadis, Th. G.; Vial, J. -C.; Bastian, T.; Chiuderi Drago, F.
Bibcode: 1999ESASP.448..297G
Altcode: 1999mfsp.conf..297G; 1999ESPM....9..297G
  No abstract at ADS

Title: Preface
Authors: Vial, J. -C.
Bibcode: 1999ESASP.446....1V
Altcode: 1999soho....8....1V
  No abstract at ADS

Title: Multi-Instrument Study Of The Evolution Of An Active Region
Authors: Regnier, S.; Amari, T.; Solomon, J.; Vial, J. C.; Mickey, D.
Bibcode: 1999ESASP.446..571R
Altcode: 1999soho....8..571R
  We follow, for about half a solar rotation, the dynamic evolution of
  an acive region (AR 8151) which exhibited a single heading sunspot
  and a more diffuse following magnetic flux and a filament eruption
  on 12 February 1998 at 13:51. For longitudinal magnetic observations,
  we use the MDI (SoHO) magnetograph and for vector magnetic fields the
  IVM (Mees Solar Observatory, Hawaii). The dynamic evolution is derived
  from time-sequence images in the Fe XII line (195 Angstrom) from EIT
  (SoHO). Density and abundance diagnostic of the filament are obtained
  from SoHO spectrometers (CDS, SUMER).

Title: Hydrogen Lyman Lines and Continuum Emission in a Polar-Crown
    Prominence Observed with SUMER/SOHO
Authors: Schmieder, B.; Kucera, T.; Heinzel, P.; Vial, J. -C.
Bibcode: 1999ESASP.446..605S
Altcode: 1999soho....8..605S
  We present, for the first time, a quasi-simultaneous spectroscopic
  observation of the whole Lyman series of HI and continuum in a
  quiescent prominence. Namely we have extended our previous study of
  higher Lyman lines to lower members of the series, particularly
  L-alpha and L-beta. For the latter two lines, we compare our
  calibrated profiles (free of geocoronal absorption) with previous
  data from OSO-8 LPSP spectrometer and (for L-alpha) from UVSP/SMM. We
  demonstrate the importance of Lyman lines for studies of the base of
  the prominence-corona transition region.

Title: La mission solaire SOHO: quelques résultats récents
Authors: Vial, J.
Bibcode: 1999CRASB.327.1201V
Altcode:
  After more than 3 years of operations, the SOHO solar mission
  has brought a large body of new results, the full exploitation of
  which continues. SOHO has provided evidence of the role of magnetic
  reconnection at many different spatial scales (including scales smaller
  than any spatial resolution) in direct heating by the Joule effect, or
  in generating MHD waves or accelerating particles. Reconnection seems
  to occur very low in the atmosphere with a permanent reshuffling of
  magnetic fields resulting from flux emergence at the borders of the
  supergranulation network. SOHO has also demonstrated the multifluid
  nature of the solar wind in the low corona where ion (and proton)
  temperatures are higher than electron temperatures. This ion heating
  can be explained by resonance between MHD waves and ion (and proton)
  gyration around the field lines. Such conclusions (and others) will
  be tested over the next few years with new observations from SOHO.

Title: 8th SOHO Workshop: Plasma Dynamics and Diagnostics in the
    Solar Transition Region and Corona
Authors: Vial, J. -C.; Kaldeich-Schü, B.
Bibcode: 1999ESASP.446.....V
Altcode: 1999soho....8.....V
  No abstract at ADS

Title: Plasma Diagnostics Of A Solar Prominence Observed On 12 June
    1997 by EIT, Sumer And CDS
Authors: Madjarska, M. S.; Vial, J. -C.; Bocchialini, K.; Dermendjiev,
   V. N.
Bibcode: 1999ESASP.446..467M
Altcode: 1999soho....8..467M
  The plasma diagnostics of a quiescent prominence observed on June 12,
  1997 with SUMER, CDS and EIT instruments aboard SOHO in the frame
  of Joint Observing Programme 9 has been made. Two sets of SUMER
  observations were taken in the four spectral lines Si IV 1393.755,
  1402.770 (6-8 10<SUP>4</SUP> K) and O IV 1401.156, 1404.812 (1.7-2.0
  10<SUP>5</SUP> K) at two different slit positions on the prominence
  body. The relative line-of-sight velocities using both Si IV 1393.755
  and 1402.770 lines are derived. The electron density (derived
  from the intensity ratio of O IV 1401.156 to 1404.812 lines) in the
  prominence-corona interface is determined for both slit positions. CDS
  obtained 10 rasters in Si X 347.40, He I 584.33, Si X 356.04, Fe XVI
  360.76, Mg IX 368.06, O V 629.73 lines covering a temperature range
  from 10<SUP>4</SUP> to 10<SUP>6</SUP> K. By analysing the CDS spectra
  in He I and O V ions the relative line-of-sight velocity maps with
  regards to the quiet sun are derived.

Title: SOHO/SUMER observations and analysis of hydrogen Lyman lines
    in a quiescent prominence
Authors: Schmieder, B.; Heinzel, P.; Vial, J. C.; Rudawy, P.
Bibcode: 1999SoPh..189..109S
Altcode:
  A quiescent prominence was observed in June 1997 by instruments
  onboard the SOHO spacecraft: the Solar Ultraviolet Measurements of
  Emitted Radiation (SUMER), Coronal Diagnostic Spectrometer (CDS)
  and Extreme-Ultraviolet Imaging Telescope (EIT), along with the
  coronagraph of the Wrocław University Observatory at Bialków and
  the spectrograph of the Ondřejov Observatory. We present prominence
  observations in higher lines of the hydrogen Lyman series (from Lδ
  to L-9), together with some other UV lines obtained by SUMER. We
  extract the basic characteristics of the calibrated line profiles
  of these Lyman lines and compare them with the theoretical profiles
  computed from three kinds of NLTE models which also include prominence
  filamentation. Our principal result is that the current NLTE models are
  in principle capable of explaining the SUMER calibrated intensities
  in the observed Lyman lines. We also find that in order to fit all
  these lines, one has to consider a prominence-corona transition region
  (PCTR) with a temperature gradient. At low pressures, higher Lyman
  lines are still rather sensitive to the incident radiation which must
  be carefully taken into account in the modeling. From PCTR models,
  which also take into account the effect of ambipolar diffusion on the
  heating, we have derived the formation depths for the Lyman series
  lines. High Lyman lines seem to be formed just at the base of the PCTR.

Title: Plasma dynamics and diagnostics in the solar transition region
    and corona. Proceedings.
Authors: Vial, J. -C.; Kaldeich-Schürmann, B.
Bibcode: 1999pdds.book.....V
Altcode:
  No abstract at ADS

Title: The Coarse Versus The Fine Structure Of The Quiet-Sun
    Chromospheric And Transition Region Network
Authors: Patsourakos, Spyridwn; Vial, J. -C.; Gabriel, A. -H.;
   Bellamine, N.
Bibcode: 1999ESASP.446..537P
Altcode: 1999soho....8..537P
  The chromospheric and transition region network is believed to be
  the basic channel of energy and momentum that heats the corona and
  accelerates the solar wind. While at spatial scales of one supergranular
  cell the network appears to be more or less homogeneous, at smaller
  scales it possesses a finer structure. We present here observations
  made with the CDS and SUMER spectrometers on SOHO pursuing the
  investigation of the coarse and the fine structure of the quiet-Sun
  network. A two-dimensional autocorrelation method allowed us to
  deduce the temperature-variation of network's width, while well-chosen
  density-sensitive line-ratios permitted to determine its filling factor
  at different temperatures. A discussion on possible implications of our
  results for steady-state energy and momentum balance for the quiet-Sun
  is included.

Title: Multiwavelength Analysis of Network Bright Points - Coordinated
    Observations SOHO-GBO JOP No 37
Authors: Falchi, A.; Cauzzi, G.; Falciani, R.; Vial, J. -C.
Bibcode: 1999ASPC..184..261F
Altcode:
  We analyze the temporal behaviour of Network Bright Points (NBPs)
  using a set of data acquired during coordinated observations between
  ground based observatories (mainly at the NSO/Sacramento Peak) and the
  SUMER and MDI instruments onboard SOHO. We find that, at any time,
  all NBPs present in the NaD_2 images are co-spatial within 1" with
  locations of enhanced magnetic field density, and that not all the
  NBPs identified in the low chromosphere can be identified at higher
  levels. We calculate the intensity power spectrum for each NBP in
  several low-chromospheric signatures, such as the red wing of Hα,
  NaD_2 and Hα line center. The power spectra show no power at the 5.5
  mHz frequency, while they display an enhancement at frequencies below
  2 mHz, corresponding to periods between 8 and 20 minutes.

Title: Transition-Region Network Boundaries in the Quiet Sun: Width
    Variation with Temperature as Observed with CDS on SOHO
Authors: Patsourakos, S.; Vial, J. -C.; Gabriel, A. H.; Bellamine, N.
Bibcode: 1999ApJ...522..540P
Altcode:
  We report here the results of a study of the temperature variation
  of the network boundary thicknesses in the quiet-Sun transition
  region. A Fourier-based two-dimensional autocorrelation method has
  been applied to 240<SUP>''</SUP>×240<SUP>''</SUP> rasters obtained in
  several transition-region lines by the CDS spectrometer on SOHO. The
  quantitative variation of the network boundary width with temperature
  has been obtained for the first time in a full two-dimensional field. It
  appears that network boundaries have an almost constant width up to
  a temperature of about 10<SUP>5.4</SUP> K and then fan out rapidly at
  coronal temperatures. This expansion of the transition-region network
  boundaries with temperature is found to be quantitatively in agreement
  with earlier theoretical models of the transition region.

Title: The Role of "Magnetic Dips" and "Bald Patches" for a Filament
    Observed by SOHO and GBO
Authors: Aulanier, G.; Schmieder, B.; Kucera, T.; van Driel-Gesztelyi,
   L.; Démoulin, P.; Mein, N.; Vial, J. -C.; Mein, P.
Bibcode: 1999ASPC..184..291A
Altcode:
  The studied filament was observed on Sept. 25, 1996, in Hα with
  the MSDP on the German VTT, Tenerife, as well as in Si IV with
  SOHO/SUMER. The 3-D magnetic configuration of the filament channel is
  reconstructed, using linear magnetohydrostatic (lmhs) extrapolations
  from a SOHO/MDI magnetogram, which is modified by a background magnetic
  component constraining a twisted flux-tube. This flux-tube is deformed
  by the magnetic polarities observed with SOHO/MDI. The shape and
  location of the computed "dipped field lines" are in good agreement
  with the shape of the filament and its feet observed in Hα. Some "bald
  patches" (BPs) are present where the distribution of dips reaches the
  photosphere. We find observational signatures in Si IV brightenings of
  energy release at the locations of computed "bald patch separatrices",
  defined by field lines which are tangent to the photosphere. We propose
  that the plasma is there heated by ohmic dissipation from the expected
  currents in the BP separatrices. The results show the importance of
  "dipped field lines" and "bald patches" in filament channels.

Title: Coordinated Prominence Observations by SOHO and Ground-Based
    Observatories
Authors: Schmieder, B.; Heinzel, P.; Vial, J. -C.; Malherbe, J. M.;
   Mein, P.; Rudawy, P.; Ceppatelli, G.
Bibcode: 1999ASPC..184..296S
Altcode:
  Coordinated observations obtained during the JOP12 (Joint Observing
  Programme between SOHO and ground-based instruments) allow us to
  analyse the physical conditions in a prominence of 5 June 1997 and
  its environment in the solar corona. The arch-shaped prominence shows
  either vertical or horizontal structures according to the observed
  lines (Hα with the coronagraph of the Wroclaw University Observatory
  at Bialków and lines in a broad temperature range by the Coronal
  Diagnostic Spectrometer CDS). The less dynamic behaviour of this
  prominence was shown by the persistence of bubbles in the prominence
  and confirmed by the Dopplershifts measured in CDS lines and in Hα
  by the Italian Panoramic Monochromator (IPM) filter on the THEMIS
  telescope in Tenerife. We explain the complex morphology of this
  prominence by recent 3D MHD models. Finally, we present prominence
  spectra in higher lines of the hydrogen Lyman series (from Lδ to L-9),
  together with some other UV lines. These data have been obtained by
  the Solar Ultraviolet Measurements of Emitted Radiation (SUMER). We
  demonstrate the basic characteristics of the calibrated line profiles
  of Lyman lines and compare them with the theoretical profiles computed
  from isothermal-isobaric models. This leads to some constraints on
  the environment of the prominence.

Title: Coordinated observations between SOHO/SUMER and ground during
the 1998 total eclipse: Non-thermal line broadenings and electron
    densities in a polar coronal hole
Authors: Patsourakos, S.; Vial, J. -C.; Gabryl, J. -R.; Koutchmy,
   S.; Schühle, U.
Bibcode: 1999AIPC..471..285P
Altcode: 1999sowi.conf..285P
  Alfvén waves represent one of the most prominent ways of heating the
  solar corona and accelerating the solar wind. One of their signatures
  is to broaden the spectral lines in excess of their thermal width. Here
  we aim to combine observations of non-thermal broadenings measured
  by SUMER in OVI (1037.6 Å) line and electronic densities derived
  from white-light observations during the 1998 total eclipse. After
  checking the validity of the frequently-used assumption of equal ion
  and electron temperatures, we compute the variation of the non-thermal
  velocity as a function of height in an interplume region within the
  south polar coronal hole.

Title: Filament channel structures in a SI IV line related to a 3d
    magnetic model
Authors: Kucera, T. A.; Aulanier, G.; Schmieder, B.; Mein, N.; Vial,
   J. -C.
Bibcode: 1999SoPh..186..259K
Altcode:
  A recent 3D magnetic model of filament support (Aulanier and Démoulin,
  1998) has shown that specific morphologies derived from the model, based
  on SOHO/MDI magnetograms, match quite well with the observations of a
  filament observed in Hα and Ca ii lines with the German telescope VTT
  in Tenerife on 25 September 1996 (Aulanier et al., 1998, 1999a). Some
  predictions of this model concern the filament channel. To continue the
  comparison of model and data, we have investigated the same filament
  region observed in ultraviolet by the SOHO spectrometers SUMER and
  CDS. The elongated EUV fine structures in the filament channel observed
  in the Si iv 1393.76 Å line by SUMER have similar orientations
  and locations to features predicted by the model of Aulanier et
  al. (1999a). These regions are near the bases of field lines which
  tangentially join to the photosphere in so called 'bald patches' and
  are parts of large arcades above the filament channel. In addition,
  we consider the Si iv Doppler shifts in these structures and compare
  them to what might be expected from the model field structure. Our
  study also suggests that the filament has a very low opacity in Si iv,
  lower than that of the O v line observed by CDS.

Title: Multiresolution wavelet analysis of SUMER/SOHO observations
    in a solar prominence
Authors: Blanco, S.; Bocchialini, K.; Costa, A.; Domenech, G.; Rovira,
   M.; Vial, J. -C.
Bibcode: 1999SoPh..186..281B
Altcode:
  We have studied through a multiresolution wavelet analysis the
  oscillations in a limb prominence. Intensity fluctuations in time and
  height corresponding to different lines of Si iv and O iv observed
  with SUMER on board SOHO have been analyzed in the wavelet bands of
  J<SUB>3</SUB>= 1 min 36 s to 3 min 12 s and J<SUB>4</SUB>=3 min 12
  s to 6 min 24 s. For all species, oscillations in the J<SUB>4</SUB>
  band were dominant. We found relevant differences between the behavior
  of line D<SUB>1</SUB> (1393.76 Å) corresponding to Si iv and the set
  D<SUB>2</SUB> (1401.16 Å), D<SUB>3</SUB> (1404.81 Å), D<SUB>4</SUB>
  (1402.77 Å) corresponding to O iv, O iv and Si iv respectively. We
  also report the identification of a pulse in the intensity of the line
  D<SUB>1</SUB> that appears in the range of 15-20 min. This disturbance
  seems to travel with a speed of about 170 km s<SUP>−1</SUP>.

Title: Solar Wind Outflow and the Chromospheric Magnetic Network
Authors: Hassler, Donald M.; Dammasch, Ingolf E.; Lemaire, Philippe;
   Brekke, Pal; Curdt, Werner; Mason, Helen E.; Vial, Jean-Claude;
   Wilhelm, Klaus
Bibcode: 1999Sci...283..810H
Altcode:
  No abstract at ADS

Title: Oscillations of the upper chromosphere
Authors: Gouttebroze, P.; Vial, J. -C.; Bocchialini, K.; Lemaire,
   P.; Leibacher, J. W.
Bibcode: 1999SoPh..184..253G
Altcode:
  Variations of intensity and wavelength in several UV lines have been
  observed with the SUMER spectroheliometer onboard SOHO, and they have
  been analysed to obtain oscillation spectra and phase differences
  between lines of different ions. Lines intensities of neutral or
  singly ionized atoms (with temperature of formation ≤ 30 000 K)
  exhibit an increase of oscillatory power between 2.5 and 7 mHz, which
  may be considered as the signature of p modes. Lines of highly ionized
  elements (with a temperature of formation ≥ 50 000 K) yield power
  spectra which are continuously decreasing with frequency. Brightness
  variations of the continuum at different wavelengths between 1000
  and 1400 Å present oscillations in the same frequency range. Thus,
  p modes seem to be efficiently stopped by the transition region. No
  clear evidence is found for the existence of a chromospheric oscillation
  mode. Phase comparisons between lines formed at different altitudes
  (in particular Si i and Si ii) indicate that these lines oscillate in
  phase, within the precision of the measurements.

Title: Eruptive filament of May 31, 1997, observed by SOHO.
Authors: Schmieder, B.; Heinzel, P.; Vial, J. -C.; Delaboudinière,
   J. -P.; Delannée, C.
Bibcode: 1999joso.proc..147S
Altcode:
  In the frame of the SUMER/CDS Joint Programme (JOP 17) the authors
  have detected the four Lyman lines in an erupting filament. The
  strong self-absorption in these lines, already reported for quiescent
  filaments, is still present in this highly dynamical event, but the
  authors observe a significant red asymmetry in the intensities of the
  two peaks. They ascribe it to an upward bulk motion of the filament,
  which they can actually see on a series of EIT images taken in the
  Fe XII line. Both sets of observations can lead to a determination
  of the velocity vector. The Doppler velocities are also derived from
  other lines detected by SUMER/CDS and can be correlated with the
  observations of the Pic-du-Midi MSDP obtained for this event. The
  filament eruption was also well observed by other GBO instruments in
  the Hα line (Meudon and Ondřejov).

Title: Outflow Velocities at the Base of a Polar Coronal Hole During
    the 1998 Total Eclipse
Authors: Patsourakos, S.; Vial, J. -C.; Gabryl, J. -R.; Koutchmy,
   S.; Schühle, U.
Bibcode: 1999SSRv...87..291P
Altcode:
  Polar coronal holes represent the most convincing site from which the
  high-speed solar wind originates. Here we report high-accuracy Doppler
  shifts measured in the O VI (1037.6 Å) line obtained by SUMER on SOHO
  inside an interplume region within the south polar coronal hole. We
  infer limits on the outflow velocity and draw hints about the flow
  geometry.

Title: Solar chromospheric structures observed in UV ressonance
lines : a multivariate analysis approach
Authors: Patsourakos, S.; Bocchialini, K.; Vial, J. -C.
Bibcode: 1999CR2...322..337P
Altcode:
  We present the results of a statistical analysis carried out from a data
  base of 6 solar chromospheric emission lines recorded simultaneously
  and with high spectral resolution. An empirical and a clustering method
  for separating the different solar structures contributions have been
  used and been found in a good agreement. Mean profiles corresponding to
  the different populations have been built. Correlations of different
  parameters for each profile allowed us to deduce different properties
  of the solar chromosphere, such as the existence of magnetic canopies
  and downflows in active regions.

Title: Study of solar prominences with data obtained with the SUMER
    instrument on B oard SOHO satellite.
Authors: Rovira, M. G.; Costa, A.; Blanco, S.; Domenech, G.; Vial,
   J. C.
Bibcode: 1998larm.confE..13R
Altcode:
  The oscillations in a limb prominence have been studied through a
  multiresolution wavelet analysis. We found relevant differences between
  the behavior of Si IV and O IV lines. We also report the identification
  of a pulse in a range between 15-20 min. This disturbance seems to
  travel with a speed of about 170 km/s.

Title: Filament Observations with SOHO Sumer/cds: The Behaviour of
    Hydrogen Lyman Lines
Authors: Schmieder, B.; Heinzel, P.; Kucera, T.; Vial, J. -C.
Bibcode: 1998SoPh..181..309S
Altcode:
  On 21 September 1996, a filament close to an area of enhanced network
  was observed with the Solar Ultraviolet Measurements of Emitted
  Radiation (SUMER) spectrometer and Coronal Diagnostic Spectrometer
  (CDS). CDS provided intensity, Doppler shift and linewidth maps of the
  region in six lines whose temperature range covers 10<SUP>4</SUP> to
  10<SUP>6</SUP> K. SUMER observations consisted of maps of the region
  in four hydrogen Lyman lines (Lδ, L∈, L-6, L-7) and a Svi line
  (944 Å). In all the Lyman lines we detect a central absorption
  and an asymmetry in the intensity of the two peaks. First NLTE
  computations indicate that such reversed Lyman profiles and their
  absolute intensities can be reproduced with the existing filament models
  provided that we take into account a prominence-corona transition region
  (PCTR). We discuss the Lyman lines' asymmetry in terms of macroscopic
  flows by comparison with the Hei line Doppler shifts observed with CDS.

Title: Solar chromospheric structures observed in UV resonance lines:
    a multivariate analysis approach.
Authors: Patsourakos, S.; Bocchialini, K.; Vial, J. -C.
Bibcode: 1998CRASB.326..337P
Altcode:
  The authors present the results of a statistical analysis carried out
  from a data base of six solar chromospheric emission lines recorded
  simultaneously and with high spectral resolution. An empirical and
  a clustering method for separating the different solar structure
  contributions have been used and found to be in good agreement. Mean
  profiles corresponding to the different populations have been
  built. Correlations of different parameters for each profile allowed
  one to deduce different properties of the solar chromosphere, such as
  the existence of magnetic canopies and downflows in active regions.

Title: Statistical analysis of solar bright points observed with
    the SOHO spacecraft.
Authors: Régnier, S.; Bocchialini, K.; Vial, J. -C.; Delaboudinière,
   J. -P.; Thompson, W.
Bibcode: 1998CRASB.326..211R
Altcode: 1998CR2...326..211R
  Bright points, small and short lifetime structures, appear permanently
  in the atmosphere and could be associated with magnetic reconnections,
  potential sources of coronal heating. Such structures have been
  observed with the coronal instruments on-board SOHO and a statistical
  analysis was carried out in order to find the signature of very small
  scale structures.

Title: Cor-I: a coronal white-light imager for a solar probe
Authors: Vial, J. -C.; Koutchmy, S.; Habbal, S. R.
Bibcode: 1998AdSpR..21..291V
Altcode:
  Solar and heliospheric observations acquired over several decades,
  have shown that the corona is a highly structured medium. There is
  no doubt that these structures reflect the response of the coronal
  plasma - confined by the highly inhomogeneous magnetic field - to
  different forms of energy input. While in-situ plasma measurements
  have provided the characteristic properties of both fast and slow
  solar winds, they have fallen short in connecting them to the source
  regions of the wind. A near-Sun flyby mission offers an unprecedented
  opportunity to explore the solar wind at distances much closer to
  the Sun than ever achieved before. However, it is essential that
  in-situ measurements be coordinated with simultaneous imaging of
  the structures encountered in the corona. We present the concept and
  design of a white-light imager called Cor-I, as a key instrument for a
  near-Sun flyby mission which makes it possible to distinguish spatial
  structures from temporal changes in the plasma parameters. With the
  inference of the electron density from the Thomson scattered emission,
  white-light measurements are also a very powerful tool for quantitative
  studies of the acceleration region of the solar wind. In addition, the
  proposed instrument carries the potential for discovery of transient
  events and waves in these parts of the acceleration region of fast and
  slow solar winds that are inaccessible to in-situ plasma instruments.

Title: SUMER/SOHO Filament Observations in Selected Lyman Lines
Authors: Schmieder, B.; Kucera, T.; Heinzel, P.; Vial, J. -C.
Bibcode: 1998ASPC..150..205S
Altcode: 1998IAUCo.167..205S; 1998npsp.conf..205S
  No abstract at ADS

Title: EUV and Microwave Observations of a Filament
Authors: Chiuderi-Drago, F.; Bocchialini, K.; Lamartinie, S.;
   Vial, J. -C.; Bastian, T.; Alissandrakis, C. E.; Harrison, R.;
   Delaboudiniere, J. -P.; Lemaire, P.
Bibcode: 1998ASPC..150...55C
Altcode: 1998IAUCo.167...55C; 1998npsp.conf...55C
  No abstract at ADS

Title: Solar Probe: The RAMSES Proposal
Authors: Le Quéau, D.; Roux, A.; Vial, J. -C.
Bibcode: 1998ESASP.417...75L
Altcode: 1998cesh.conf...75L
  No abstract at ADS

Title: Quiescent filament diagnostic.
Authors: Lamartinie, S.; Bocchialini, K.; Vial, J. -C.; Chiuderi-Drago,
   F.; Harrison, R.; Alissandrakis, C. E.
Bibcode: 1998joso.proc..139L
Altcode:
  UV observations of a quiescent filament were performed on July 28,
  1996 by SUMER and CDS, two spectrometers onboard SOHO.

Title: Solar Prominence Diagnostics (Review)
Authors: Vial, J. -C.
Bibcode: 1998ASPC..150..175V
Altcode: 1998IAUCo.167..175V; 1998npsp.conf..175V
  No abstract at ADS

Title: Height variations of prominence plasma parameters
Authors: Kotrč , P.; Heinzel, P.; Vial, J. -C.; Rompolt, B.
Bibcode: 1998PAICz..88..208K
Altcode:
  No abstract at ADS

Title: 3-D Modelling of a Filament Observed in Hα and with SOHO
Authors: Aulanier, G.; Schmieder, B.; Démoulin, P.; Mein, N.; van
   Driel-Gesztelyi, L.; Mein, P.; Vial, J. C.; Deforest, C.
Bibcode: 1998ESASP.417..217A
Altcode: 1998cesh.conf..217A
  No abstract at ADS

Title: Coronal jet turbulent activity to explain distorted emission
    line
Authors: Loucif, M. L.; Ben Jaffel, L.; Koutchmy, S.; Vial, J. -C.
Bibcode: 1998ESASP.421..303L
Altcode: 1998sjcp.conf..303L
  No abstract at ADS

Title: Polar jets and plasmoids:Results from JOP 57
Authors: Delannee, C.; Koutchmy, S.; Delaboudiniere, J. -P.; Hochedez,
   J. -F.; Vial, J. -C.; Dara, H.; Georgakilas, A.
Bibcode: 1998ESASP.421..129D
Altcode: 1998sjcp.conf..129D
  No abstract at ADS

Title: Transient Events and Their Solar Magnetic Field
Authors: Vial, J. -C.
Bibcode: 1998HiA....11..877V
Altcode:
  No abstract at ADS

Title: Space solar physics : theoretical and observational issues
    in the context of the SOHO mission
Authors: Vial, Jean Claude; Bocchialini, Karine; Boumier, Patrick
Bibcode: 1998LNP...507.....V
Altcode: 1998sspt.conf.....V
  No abstract at ADS

Title: Filament observations with SOHO SUMER/CDS.
Authors: Schmieder, B.; Kučera, T.; Heinzel, P.; Vial, J. -C.
Bibcode: 1998joso.proc..136S
Altcode:
  During a coordinated campaign between SOHO and ground-based instruments
  a filament located close to the central meridian has been the target
  of SUMER and CDS spectrometers on September 21, 1996.

Title: On a Possible Mechanism of Quiescent Prominence Destabilization
Authors: Nenovski, P.; Dermendjiev, V. N.; Madjarska, M. S.; Vial,
   J. -C.
Bibcode: 1998ASPC..150..354N
Altcode: 1998IAUCo.167..354N; 1998npsp.conf..354N
  No abstract at ADS

Title: Emission of hydrogen lines by moving solar prominences.
Authors: Gontikakis, C.; Vial, J. -C.; Gouttebroze, P.
Bibcode: 1997A&A...325..803G
Altcode:
  We study the radiative transfer processes occurring in a plane-parallel
  slab standing vertically above the chromosphere and moving upward
  as a solid body. This structure simulates a prominence in the phase
  of eruption or a quiescent prominence where the plasma presents bulk
  velocities. We use partial redistribution for the description of the
  resonance scattering in the hydrogen Lα and Lβ lines. We compute
  the Lα, Lβ and Hα emergent line profiles of hydrogen for different
  velocities. We derive the variation of the emitted intensities as a
  function of the velocity for various temperatures and thicknesses. We
  discuss our results in view of the diagnostic of erupting prominences
  in Lyman lines that SOHO observations can provide.

Title: Spectral diagnostics for eruptive prominences
Authors: Gontikakis, C.; Vial, J. -C.; Gouttebroze, P.
Bibcode: 1997SoPh..172..189G
Altcode: 1997ESPM....8..189G
  The diagnostic of eruptive prominences needs the development of
  new tools. Here we propose the Lyman and Balmer lines of hydrogen,
  which are important in the radiative budget. In the NLTE radiative
  transfer calculations, we include the effect of the outward motion
  of the structure associated with the eruption of the prominence. The
  treatment of the resonance scattering of Lα and Lβ with partial
  redistribution gives higher intensities, and a higher ionization than
  the complete redistribution, but the two approaches converge to the same
  solution as the velocity increases. As a first step in the diagnostic,
  we present new results concerning the variation of the integrated
  intensities of hydrogen lines with respect to the radial velocity.

Title: Formation of CA II Lines in Solar Prominences
Authors: Gouttebroze, P.; Vial, J. -C.; Heinzel, P.
Bibcode: 1997SoPh..172..125G
Altcode: 1997ESPM....8..125G
  We compute the profiles of the resonance lines and infrared
  triplet of ionized calcium emitted by some representative models of
  prominences. These models consist of plane-parallel slabs of different
  temperatures, pressures and thicknesses, standing vertically above
  the solar surface. These slabs are assumed to be observed at the limb,
  and to be perpendicular to the line of sight. They are irradiated by
  the Sun on both sides, and the incoming intensities, at every relevant
  wavelength, are taken from observations. The model atom includes 3
  stages of ionization (Cai, Caii and Caiii) with 5 discrete levels for
  Caii. We study the relations between emitted intensities and physical
  properties of the slabs, and compare the intensities emitted in Caii and
  hydrogen lines for the same set of models. As a result of ionization,
  the intensity decreases more rapidly with temperature in Caii lines than
  in Hi lines, so that the ratio of Caii to Hi line intensities may be
  used as a temperature indicator. The intensity ratio between resonance
  and infrared lines of Caii depends principally on the optical thickness
  of the structure. At high pressure and low temperature, the ratio
  Caii 8542Å/Hβ is found to increase with pressure. This behaviour,
  which is due to the saturation of Hβ, is opposite to that found by
  Heasley and Milkey (1978) for low pressures (optically thin structures).

Title: Polar Jets and Plasmoids: Preliminary Results from JOP 57
Authors: Delannée, C.; Koutchmy, S.; Delaboudiniè, J. -P.; Hochedez,
   J. -F.; Vial, J. -C.; Dara, H.; Georgakilas, A.
Bibcode: 1997ESASP.404..327D
Altcode: 1997cswn.conf..327D
  No abstract at ADS

Title: Dynamics of Minor Solar Activity \newline Coordinated
    Observations SOHO-GBO JOP #37
Authors: Cauzzi, G.; Vial, J. C.; Falciani, R.; Falchi, A.; Smaldone,
   L. A.
Bibcode: 1997ASPC..118..309C
Altcode: 1997fasp.conf..309C
  We present a program for coordinated observations between ground based
  observatories, mainly NSO/Sacramento Peak, and several instruments
  onboard SOHO (primarily SUMER). The scientific goal is the study of
  small activity phenomena, at high spatial and temporal resolution.

Title: NLTE Analysis of SUMER Filament Observations on SOHO
Authors: Heinzel, P.; Schmieder, B.; Vial, J. -C.
Bibcode: 1997ESASP.404..427H
Altcode: 1997cswn.conf..427H
  No abstract at ADS

Title: Solar Magnetic Field Events related to CMEs observed with SOHO
    (MDI, EIT, SUMER, LASCO)
Authors: Schmieder, B.; van Driel-Gesztelyi, L.; Wiik, J. E.; Thompson,
   B.; de Forest, C.; Saint Cyr, C.; Vial, J. -C.; Nitta, N.; Simnett, G.
Bibcode: 1997IAUJD..19E..42S
Altcode:
  We shall present two CMEs observed by LASCO during the minimum of
  activity of the Sun. These are associated with filament disparitions
  brusques (DB). CME and DB definitively seem to be consequences of global
  magnetic field instability, which causes reconnection of pre-existing
  field lines in the corona. We shall demonstrate how cancelling flux
  and converging magnetic field in photosphere may destabilize coronal
  streamers overlying one or two filament channels.

Title: Statistical Analysis of a Bright Point Observed Simultaneously
    in Two Chromospheric and Transition Region Lines by SUMER
Authors: Bocchialini, K.; Vial, J. -C.; Einaudi, G.
Bibcode: 1997ESASP.404..211B
Altcode: 1997cswn.conf..211B
  No abstract at ADS

Title: First Results of the SUMER Telescope and Spectrometer on SOHO -
    I. Spectra and Spectroradiometry
Authors: Wilhelm, K.; Lemaire, P.; Curdt, W.; Schühle, U.; Marsch, E.;
   Poland, A. I.; Jordan, S. D.; Thomas, R. J.; Hassler, D. M.; Huber,
   M. C. E.; Vial, J. -C.; Kühne, M.; Siegmund, O. H. W.; Gabriel, A.;
   Timothy, J. G.; Grewing, M.; Feldman, U.; Hollandt, J.; Brekke, P.
Bibcode: 1997SoPh..170...75W
Altcode:
  SUMER - the Solar Ultraviolet Measurements of the Emitted Radiation
  instrument on the Solar and Heliospheric Observatory (SOHO) - observed
  its first light on January 24, 1996, and subsequently obtained a
  detailed spectrum with detector B in the wavelength range from 660
  to 1490 Å (in first order) inside and above the limb in the north
  polar coronal hole. Using detector A of the instrument, this range
  was later extended to 1610 Å. The second-order spectra of detectors
  A and B cover 330 to 805 Å and are superimposed on the first-order
  spectra. Many more features and areas of the Sun and their spectra
  have been observed since, including coronal holes, polar plumes and
  active regions. The atoms and ions emitting this radiation exist at
  temperatures below 2 × 10<SUP>6</SUP> K and are thus ideally suited
  to investigate the solar transition region where the temperature
  increases from chromospheric to coronal values. SUMER can also be
  operated in a manner such that it makes images or spectroheliograms
  of different sizes in selected spectral lines. A detailed line profile
  with spectral resolution elements between 22 and 45 mÅ is produced for
  each line at each spatial location along the slit. From the line width,
  intensity and wavelength position we are able to deduce temperature,
  density, and velocity of the emitting atoms and ions for each emission
  line and spatial element in the spectroheliogram. Because of the high
  spectral resolution and low noise of SUMER, we have been able to detect
  faint lines not previously observed and, in addition, to determine
  their spectral profiles. SUMER has already recorded over 2000 extreme
  ultraviolet emission lines and many identifications have been made on
  the disk and in the corona.

Title: High resolution solar ultraviolet measurements
Authors: Lemaire, P.; Wilhelm, K.; Schühle, U.; Curdt, W.; Poland,
   A. I.; Jordan, S. D.; Thomas, R. J.; Hassler, D. M.; Vial, J. -C.
Bibcode: 1997AdSpR..20.2249L
Altcode:
  The increase of our understanding of the processes acting in the solar
  corona and maintaining it is strongly dependent on the quality of the
  data that are obtained to check theories. The fine structure of the
  solar atmosphere seen from the photosphere and extending to the hottest
  parts of the corona requires data with high resolution in all parameter
  space (angular, spectral and temporal). To constrain the hypotheses that
  are proposed to describe the solar corona, it is necessary to establish
  an accurate energy budget taking into account the processes which are
  acting from the chromosphere to the corona. Some requirements can be
  established and compared with the data collected so far (or about to
  be collected) with the present SUMER (Solar Utraviolet Measurements
  of Emitted Radiations) instrumentation.

Title: Simulated white-light images of coronal structures as obtained
    by the CORI imager on-board a solar probe
Authors: Patsourakos, S.; Vial, J. -C.
Bibcode: 1997AIPC..385..129P
Altcode: 1997recs.conf..129P
  A white-light coronal imager called CORI to be implemented on a solar
  probe has been proposed by Habbal et al. (1995). Its scientific
  objectives concern the investigation of the solar corona and the
  source of the solar wind. It is aimed as a complement to the in-situ
  instruments. This paper presents some simulations of the images
  that will be recorded when observing solar structures of increasing
  complexity during the close encounter phase of the trajectory. These
  attempts should be considered as a first step towards the assessment
  of the full scientific capabilities of CORI and the definition of the
  observing strategy.

Title: First Results of the SUMER Telescope and Spectrometer on SOHO -
    II. Imagery and Data Management
Authors: Lemaire, P.; Wilhelm, K.; Curdt, W.; SchÜle, U.; Marsch,
   E.; Poland, A. I.; Jordan, S. D.; Thomas, R. J.; Hassler, D. M.; Vial,
   J. C.; KÜhne, M.; Huber, M. C. E.; Siegmund, O. H. W.; Gabriel, A.;
   Timothy, J. G.; Grewing, M.
Bibcode: 1997SoPh..170..105L
Altcode:
  SUMER - Solar Ultraviolet Measurements of Emitted Radiation - is not
  only an extreme ultraviolet (EUV) spectrometer capable of obtaining
  detailed spectra in the range from 500 to 1610 Å, but, using the
  telescope mechanisms, it also provides monochromatic images over
  the full solar disk and beyond, into the corona, with high spatial
  resolution. We report on some aspects of the observation programmes
  that have already led us to a new view of many aspects of the Sun,
  including quiet Sun, chromospheric and transition region network,
  coronal hole, polar plume, prominence and active region studies. After
  an introduction, where we compare the SUMER imaging capabilities to
  previous experiments in our wavelength range, we describe the results
  of tests performed in order to characterize and optimize the telescope
  under operational conditions. We find the spatial resolution to be
  1.2 arc sec across the slit and 2 arc sec (2 detector pixels) along
  the slit. Resolution and sensitivity are adequate to provide details
  on the structure, physical properties, and evolution of several solar
  features which we then present. Finally some information is given on
  the data availability and the data management system.

Title: Low Transition-Region Characteristics of Equatorial Coronal
    Holes
Authors: Patsourakos, S.; Bocchialini, K.; Vial, J. -C.
Bibcode: 1997ESASP.404..577P
Altcode: 1997cswn.conf..577P
  No abstract at ADS

Title: Diagnostic and observations of quiescent and
Authors: Vial, J. -C.; Gontikakis, C.; Bocchialini, K.; Gouttebroze, P.
Bibcode: 1997IAUJD..19E..55V
Altcode:
  We present a new diagnostic tool for investigating the plasma conditions
  in a moving structure in the solar corona, such as an eruptive filament
  or prominence. It relies on NLTE radiative transfer calculations and
  the signatures of outward directed velocities on Lyman and Balmer lines
  profiles. Preliminary observations with SUMER on SOHO are discussed.

Title: Microwave and UV observations of filaments with SOHO and
    the VLA
Authors: Alissandrakis, C. E.; Drago, F.; Bastian, T.; Bocchialini,
   K.; Delaboudiniere, J. -P.; Lemaire, P.; Vial, J. -C.; Harrison,
   R. A.; Thompson, B.
Bibcode: 1997ASPC..118..289A
Altcode: 1997fasp.conf..289A
  Observations performed in coordination between SOHO instruments and
  ground-based observatories offer the unique possibility to derive
  information simultaneously in several wavelengths formed at different
  altitudes and/or temperatures in the solar atmosphere. The SUMER and
  CDS spectrometers, the imaging telescope EIT aboard SOHO, and the VLA
  provide complementary information in the UV and the radio ranges. We
  illustrate such a coordination with observations of filaments in the
  transition region, performed in July 1996. The observations in the UV
  between 10(4) and 10(6) K provide the differential emission measure
  as a function of temperature; this can be used to compute the expected
  brightness temperature in the microwave range and check models of the
  filament-corona transition region.

Title: First Results of SOHO's Joint Observing Programme 40
Authors: Patsourakos, S.; Bocchialini, K.; Vial, J. -C.
Bibcode: 1997IAUJD..19E..38P
Altcode:
  The first results of SOHO's JOP 40 are presented. This program
  proposes to study the chromospheric to transition region of equatorial
  coronal holes in order to derive parameters such as the temperature,
  the density, using different lines formed at different altitudes,
  in different places: the boundary of a coronal hole or the central
  region, on the disk. The two components of the chromospheric quiet
  Sun, network and internetwork, should be observed, in and out of an
  equatorial coronal hole.

Title: High-Chromosphere and Low-Transition-Region Network: a
    Different Organization in an Equatorial Coronal Hole?
Authors: Bocchialini, K.; Vial, J. -C.
Bibcode: 1996SoPh..168...37B
Altcode:
  In order to investigate the high chromosphere and the low transition
  region in a coronal hole, we have analysed Ca II, Mg II and hydrogen
  resonance lines, recorded by the OSO-8 spectrometer in 1975. We
  present the comparison between average profiles observed in and out
  of the equatorial coronal hole which was at the center of the solar
  disk between 27 and 29 November, 1975. We separate internetwork and
  quiet-Sun (network+internetwork) profiles: for the internetwork, we
  observe that the hydrogen and Mg II profiles recorded in the hole are
  stronger than the profiles recorded out of the hole; a similar result,
  but with a much lower contrast, is found for the quiet Sun. We discuss
  this surprising result.

Title: Prominence Thread Models Including Ambipolar Diffusion
Authors: Fontenla, J. M.; Rovira, M.; Vial, J. -C.; Gouttebroze, P.
Bibcode: 1996ApJ...466..496F
Altcode:
  We present a study of the modeling of prominence slabs. Our models
  consider a collection of threads in energy balance with the surrounding
  corona and submitted to illumination from the underlying chromospheric
  layers. The models are isobaric, but temperature variations within
  the slab occur as a result of the energy balance constraint. We
  compute the non-LTE radiative transfer for a hydrogen model atom
  with five bound levels. The ionization is treated consistently with
  non-LTE radiative transfer and ambipolar diffusion (AD). The AD
  also affects the energy balance because of the transport of hydrogen
  ionization energy. We compute the emitted Lyman and Balmer spectra of
  our models and compare them with the observations. We find that the
  consideration of ambipolar diffusion increases the emission in Lyβ
  (and higher members of the Lyman series) as compared with the other
  lines. This contrasts with isothermal models that yield Lyβ emission
  that is too low. However, the AD models give excessive Lyβ emission,
  viz., too small a Lyα/Lyβ ratio compared with observations. We also
  compute models that include a cold core in which mechanical energy is
  dissipated. These models increase the Hα/Lβ ratio to values similar to
  the observed values for a moderate number of threads along the line of
  sight. However, these models still give too low a Lyα/Lyβ ratio. We
  conclude that the prominence observations in Lyβ show intensities
  that are not compatible with a steady state, field-aligned interface
  between the cold prominence and the hot coronal material. Also, the
  observations are not consistent with an isothermal slab isolated from
  the corona. Consequently, we suggest that at the prominence-corona
  interface, there is a substantial angle between the temperature gradient
  and the field, although this angle is significantly smaller than 90°.

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: Cloud model with variable source function for solar Hα
    structures.
Authors: Mein, N.; Mein, P.; Heinzel, P.; Vial, J. -C.; Malherbe,
   J. M.; Staiger, J.
Bibcode: 1996A&A...309..275M
Altcode:
  The "cloud model" used to derive the physical parameters of solar
  chromospheric features is extended to the cases of non-constant
  source function and of velocity gradients. This model assumes a given
  relationship between the source function and the opacity of the cloud
  which is derived from non-LTE modelling. An algorithm using 4 points
  of the H<SUB>alpha</SUB>_ profile is proposed to derive the optical
  thickness, the line-of-sight velocity and the dopplerwidth. The
  results are compared with a 5-points inversion which does not use the
  given relationship between source function and opacity. Effects of the
  uncertainty about the radiation coming from the underlying chromosphere,
  as well as effects of data noise, are discussed. The inversion method
  is illustrated by some examples of observed profiles obtained with
  the MSDP spectrograph of the VTT telescope (Teide Observatory).

Title: A Complex Diagnostic of Solar Prominences
Authors: Heinzel, P.; Bommier, V.; Vial, J. C.
Bibcode: 1996SoPh..164..211H
Altcode:
  We use the polarimetric and intensity measurements of Hα and HeI
  D<SUB>3</SUB> lines in solar prominences to derive the true geometrical
  thickness for several quiescent prominences. The electron densities,
  derived from the collisional depolarization in Hα by Bommier et
  al. (1994), are used to evaluate the thickness from the emission
  measure. The emission measure was obtained from the theoretical
  correlation with the Hα integrated intensity, according to Gouttebroze,
  Heinzel, and Vial (1993). Theoretical electron densities obtained by
  latter authors are also compared with those of Bommier et al. (1994) and
  we find a very good agreement between them. The prominence geometrical
  thickness exhibits a relatively large range of values from about 100 km
  up to a few 10<SUP>4</SUP> km. The plasma densities vary by almost two
  orders of magnitude in the observed structures, but the total column
  mass in the direction perpendicular to the prominence sheet seems to
  be fairly constant for the set of prominences studied.

Title: Prominence Eruption and Coronal Mass Ejections: Diagnostics
    and Future Observations from SOHO
Authors: Gontikakis, C.; Vial, J. -C.
Bibcode: 1996ApL&C..34..119G
Altcode:
  No abstract at ADS

Title: Two-dimensional Model of a Rotating Solar Prominence
    I. Observations and Preliminary Approach
Authors: Kononovich, E. V.; Gorshkov, A. B.; Smirnova, O. B.; Kotrc,
   P.; Vial, J. -C.
Bibcode: 1996ASPC...95..251K
Altcode: 1996sdit.conf..251K
  No abstract at ADS

Title: SUMER - Solar Ultraviolet Measurements of Emitted Radiation
Authors: Wilhelm, K.; Curdt, W.; Marsch, E.; Schühle, U.; Lemaire,
   P.; Gabriel, A.; Vial, J. -C.; Grewing, M.; Huber, M. C. E.; Jordan,
   S. D.; Poland, A. I.; Thomas, R. J.; Kühne, M.; Timothy, J. G.;
   Hassler, D. M.; Siegmund, O. H. W.
Bibcode: 1995SoPh..162..189W
Altcode:
  The instrument SUMER - Solar Ultraviolet Measurements of Emitted
  Radiation is designed to investigate structures and associated dynamical
  processes occurring in the solar atmosphere, from the chromosphere
  through the transition region to the inner corona, over a temperature
  range from 10<SUP>4</SUP> to 2 × 10<SUP>6</SUP>K and above. These
  observations will permit detailed spectroscopic diagnostics of plasma
  densities and temperatures in many solar features, and will support
  penetrating studies of underlying physical processes, including plasma
  flows, turbulence and wave motions, diffusion transport processes,
  events associated with solar magnetic activity, atmospheric heating,
  and solar wind acceleration in the inner corona. Specifically, SUMER
  will measure profiles and intensities of EUV lines; determine Doppler
  shifts and line broadenings with high accuracy; provide stigmatic
  images of the Sun in the EUV with high spatial, spectral, and temporal
  resolution; and obtain monochromatic maps of the full Sun and the inner
  corona or selected areas thereof. SUMER will be flown on the Solar
  and Heliospheric Observatory (SOHO), scheduled for launch in November,
  1995. This paper has been written to familiarize solar physicists with
  SUMER and to demonstrate some command procedures for achieving certain
  scientific observations.

Title: Some design and performance features of SUMER: solar
    ultraviolet measurements of emitted radiation
Authors: Wilhelm, Klaus; Curdt, W.; Marsh, E.; Schuehle, Udo H.;
   Lemaire, Philippe; Gabriel, Alan H.; Vial, J. -C.; Grewing, Michael;
   Huber, Martin C.; Jordan, S. D.; Poland, Arthur I.; Thomas, Roger J.;
   Kuehne, Mikhael; Timothy, J. Gethyn; Hassler, Donald M.; Siegmund,
   Oswald H.
Bibcode: 1995SPIE.2517....2W
Altcode:
  The instrument SUMER (solar ultraviolet measurements of emitted
  radiation) is designed to investigate structures and associated
  dynamical processes occurring in the solar atmosphere from the
  chromosphere through the transition region to the inner corona, over a
  temperature range from 10<SUP>4</SUP> to 2 multiplied by 10<SUP>6</SUP>
  K and above. The observations will be performed, on board SOHO (solar
  and heliospheric observatory) scheduled for launch in November 1995,
  by a scanning, normal-incidence telescope/spectrometer system in
  the wavelength range from 500 to 1610 angstrom. Spatial resolution
  requirements compatible with the pointing stability of SOHO are less
  than 1000 km corresponding to about 1-arcsec angular resolution. Doppler
  observations of EUV line shifts and broadenings should permit solar
  plasma velocity measurements down to 1 km s<SUP>-1</SUP>. We report
  here on some specific features of this instrument related to its
  pointing as well as its spatial and spectral resolution capabilities.

Title: Solar Physics from Ground-Based Infrared and Space Observations
Authors: Vial, J. -C.
Bibcode: 1995itsa.conf..221V
Altcode:
  No abstract at ADS

Title: Theoretical correlations between prominence plasma parameters
    and the emitted radiation.
Authors: Heinzel, P.; Gouttebroze, P.; Vial, J. -C.
Bibcode: 1994A&A...292..656H
Altcode:
  Recently a set of 140 prominence NLTE models has been computed using
  the best available numerical techniques (Gouttebroze et al. 1993,
  hereafter GHV). Models are represented by one-dimensional (1D) slabs
  vertically standing on the solar surface and irradiated by photospheric
  and chromospheric radiation. They are parametrized by the gas pressure
  and temperature (uniform), the geometrical thickness of the 1D slab,
  the microturbulent velocity and the height above the solar surface. As
  outputs we obtained several physical quantities and optical parameters
  like the electron density, the total hydrogen density, the optical
  thickness in hydrogen lines and continua, spectral line intensities
  etc. (see GHV). In order to establish mutual correlations between
  various plasma parameters and the basic characteristics of the
  synthesized hydrogen spectrum, we construct some basic correlation
  curves. A very important relation already mentioned in GHV concerns the
  plasma emission measure found to be closely related to the integrated
  intensity of the Balmer Hα line. We present several other correlations
  which can be divided into four categories: (i) relations between
  radiation properties themselves; (ii) radiation properties versus
  plasma parameters; (iii) the Hα source function behaviour; and (iv)
  correlations between plasma parameters. Together with the 24 presented
  figures, we discuss the physical interpretation of these correlations
  and we give some hints for their application to the observed data. When
  appropriate, we also compare our results with existing observations.

Title: About small plasmoids propagating in the solar corona
Authors: Koutchmy, S.; Bouchard, O.; Grib, S.; November, L.; Vial,
   J. -C.; Gouttebrone, P.; Koutvitsky, V.; Molodensky, M.; Solov'iev,
   L.; Veselovsky, I.
Bibcode: 1994ESASP.373..139K
Altcode: 1994soho....3..139K
  No abstract at ADS

Title: On the three-dimensional structure of coronal rays
Authors: Koutchmy, S.; Molodenskii, M. M.; Vial, J. -C.
Bibcode: 1994ARep...38..822K
Altcode:
  No abstract at ADS

Title: The Chromospheric network dynamics as derived from the analysis
    of CA II K and He I 1083 NM lines
Authors: Bocchialini, S.; Vial, J. -C.; Koutchmy, S.
Bibcode: 1994SSRv...70...57B
Altcode:
  We present results of line profile analysis of observations
  simultaneously performed around the Ca II K and He I (1083 nm) lines,
  using the Horizontal Spectrograph of the Vacuum Tower Telescope of
  NSO/SP. From the spectral analysis of a 83 min long sequence of CCD
  spectra, we derive some dynamical properties of the main components
  of the quiet chromosphere: i) the magnetic network, ii) the cell
  interior. We present a whole set of amplitude spectra near 5 and 3
  min periods for the two lines; K<SUB>3</SUB> and He I velocity spectra
  extending up to 100 mHz are also considered, for the first time.

Title: Solar chromospheric structures as observed simultaneously
    in strong UV lines I. Observations, statistical analysis and
    characteristic line profiles.
Authors: Bocchialini, K.; Vial, J. -C.
Bibcode: 1994A&A...287..233B
Altcode:
  We present a set of high resolution profiles of H Lyman α and β, Mg II
  h and k, Ca II H and K lines measured near the center of the solar disk
  and simultaneously above different solar chromospheric structures. The
  large data base provides a way of correlating different parameters in
  the different lines: correlations such as Lα reversal vs intensity,
  Lα vs Ca K are discussed. We notice that Mg II and Ca II have a similar
  behaviour, different from Lα and β. We also discuss a classification
  derived from the distribution of integrated intensities in Ca II K,
  from which average profiles (for cell, network, plage) are computed
  for the six lines and are compared with theoretical ones derived from
  several models.

Title: Moon-based UV reflecting coronagraph
Authors: Vial, J. C.; Koutchmy, S.; Smartt, R. N.
Bibcode: 1994AdSpR..14f..43V
Altcode: 1994AdSpR..14...43V
  UV observations of the solar disc, and above the limb, have evidenced
  a wide range of possible diagnostics, especially in the Lα line. On
  the disc, Lα traces the magnetic (sometimes unexpected) structuring of
  the top of the atmosphere; out from the limb, it allows measurement of
  radial velocities up to a few solar radii where most optical techniques
  fail. Other diagnostics include the kinematics of ejections (e.g. CMEs,
  but also small-scale rapidly evolving plasmoïds). We propose a
  dual-channel reflecting coronagraph combining relatively-high angular
  resolution (0.2-0.4'') with large spatial (2.5 solar radii from Sun
  center) and temporal coverage. The advantages offered by a Moon-based
  instrument are discussed.

Title: The solar corona from SOHO
Authors: Vial, J. -C.
Bibcode: 1994AdSpR..14d.181V
Altcode: 1994AdSpR..14..181V
  The heating of the solar corona and the acceleration of the solar
  wind are, after decades of observations and modelling, still open
  questions. Many processes are possible in regions of strong magnetic
  field, such as waves, currents, or impulsive events which involve
  particles acceleration. However, no conclusion has been reached up to
  now. The situation is no better in open field regions where a (quiet)
  corona also exists and the wind is faster. Apart from a theoretical
  effort, a coherent diagnostic of the relevant physical quantities such
  as densities, temperatures, velocities and their temporal and spatial
  variations, is necessary. We show how the coronal package on SOHO can
  provide the temperature and height coverage adequate to understand both
  small and large scale, closed and open field, solar structures. We give
  examples of observing programs which address some important physical
  problems. Finally, we emphasize the increase of scientific return if
  the SOHO instrumentation is considered as a unique package.

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: Dynamical Properties of the Chromosphere In and Out of the
    Solar Magnetic Network
Authors: Bocchialini, Karine; Vial, Jean-Claude; Koutchmy, Serge
Bibcode: 1994ApJ...423L..67B
Altcode:
  We present the results of a comparative analysis of an 83 minute
  time sequence of spectra taken around the Ca II and He I 1083 lines,
  near the center of the solar disk and away from active regions. We
  discuss the behavior of the Fourier spectra at low frequency: 3
  minute oscillations are well observed out of the network, and 5 minute
  oscillation waves are prominent in the network. The 5 s sampling time
  also permits the observation of the high-frequency part of the Fourier
  spectra of intensity and velocity fluctuations at different heights. At
  high frequencies, K<SUB>2V</SUB>-K<SUB>2R</SUB> and 1083 (velocity)
  results differ when magnetic and non-magnetic regions are compared.

Title: Very High Resolution Analysis of the Dynamics of a Coronal
    Plasmoid
Authors: Bouchard, O.; Koutchmy, S.; November, L.; Vial, J. -C.;
   Zirker, J. B.
Bibcode: 1994scs..conf..593B
Altcode: 1994IAUCo.144..593B
  The authors present the results of the analysis of a movie taken over a
  small field of view in the intermediate corona at a spatial resolution
  of 0.5", a temporal resolution of 1 s and a spectral passband of 7
  nm. These CCD observations were made at the prime focus of the 3.6 m
  aperture CFHT telescope during the 1991 total solar eclipse.

Title: 'SUMER' - Solar Ultraviolet Measurements of Emitted Radiation
Authors: Wilhelm, K.; Curdt, W.; Gabriel, A. H.; Grewing, M.; Huber,
   M. C. E.; Jordan, S. D.; Kuhne, M.; Lemaire, P.; Marsch, E.; Poland,
   A. I.; Schuhle, U.; Thomas, R. J.; Timothy, J. G.; Vial, J. -C.
Bibcode: 1994scs..conf..619W
Altcode: 1994IAUCo.144..619W
  SUMER is designed for the investigations of plasma flow characteristics,
  turbulence and wave motions, plasma densities and temperatures,
  structures and events associated with solar magnetic activity in the
  chromosphere, the transition zone and the corona. The spatial and
  spectral resolution capabilities of the instrument are considered in
  some detail, and a new detector concept is introduced.

Title: Theoretical Correlations Between Various Prominence Parameters
Authors: Heinzel, P.; Gouttebroze, P.; Vial, J. -C.
Bibcode: 1994scs..conf..439H
Altcode: 1994IAUCo.144..439H
  The authors present some examples of important correlations between the
  prominence plasma parameters and radiation properties. For example,
  the plasma emission measure was found to be closely related to the
  integrated Hα line intensity which provides a new diagnostic tool
  for determination of plasma densities.

Title: Wave Properties in the Upper Chromosphere and at the Base of
    the Corona
Authors: Bocchialini, K.; Vial, J. -C.; Koutchmy, S.
Bibcode: 1994scs..conf..123B
Altcode: 1994IAUCo.144..123B
  From a 83 min long sequence of observations of Ca II K and He I (1083
  nm) line profiles, some dynamical properties of the main components
  of the quiet upper chromosphere are derived: for both the magnetic
  network and the internetwork, amplitude and phase spectra of the
  Doppler velocities are presented.

Title: On the Motion of Eruptive Prominences
Authors: Molodensky, M. M.; Vial, J. -C.
Bibcode: 1994scs..conf..349M
Altcode: 1994IAUCo.144..349M
  The increase of current in filaments can be evidenced by the variation
  of its twist. The authors show two examples of such a current increase,
  the last stage of which is the filament eruption and the flare. They
  suggest a theory of the equilibrium and the eruptive motion including
  the interaction of the filament current with the magnetic fields of
  the active region and the mirror current. They take into account the
  curvature of filament.

Title: Analysis of Chromospheric Proxies of Coronal Bright Points
Authors: Bocchialini, K.; Vial, J. -C.; Koutchmy, S.; Zirker, J. B.
Bibcode: 1994ASPC...68..389B
Altcode: 1994sare.conf..389B
  No abstract at ADS

Title: Solar coronal structures
Authors: Rusin, Vojtech; Heinzel, Petr; Vial, Jean-Claude
Bibcode: 1994scs..conf.....R
Altcode: 1994IAUCo.144.....R
  No abstract at ADS

Title: On the 3D Solar Corona Structure
Authors: Koutchmy, S.; Molodensky, M. M.; Vial, J. -C.
Bibcode: 1994scs..conf..585K
Altcode: 1994IAUCo.144..585K
  The authors consider the 3D structure of the solar corona using
  eclipse observations. They use a pseudostereoscopic effect of the
  rigidly rotating corona to determine the true position of the main
  coronal structures: broad threads, rays and streamers. An example of
  stereo-view deduced from a simple analysis of results coming from the
  1991 eclipse is given. The authors conclude that large helmet streamers
  are composed by the pleats of the heliosphere current sheet projected
  on the plane of the sky.

Title: Observed Chromospheric Profiles Compared with Theoretical Ones
Authors: Bocchialini, K.; Gouttebroze, P.; Vial, J. -C.
Bibcode: 1994emsp.conf...49B
Altcode:
  No abstract at ADS

Title: on the Three-Dimensional Structure of Coronal Rays
Authors: Koutchmy, S.; Molodenskii, M. M.; Vial, J. C.
Bibcode: 1994AZh....71..925K
Altcode:
  No abstract at ADS

Title: Effects of Ambipolar Diffusion on Prominence Thread Models
Authors: Rovira, M. G.; Fontenla, J. M.; Vial, J. -C.; Gouttebroze, P.
Bibcode: 1994scs..conf..315R
Altcode: 1994IAUCo.144..315R
  The authors have improved previous model calculations of the
  prominence-corona transition region including the effect of the
  ambipolar diffusion in the statistical equilibrium and energy balance
  equations. They show its influence on the different parameters that
  characterize the resulting prominence theoretical structure. They
  take into account the effect of the partial frequency redistribution
  in the line profiles and total intensities calculations.

Title: Analysis of the Chromospheric Proxies of Coronal Bright Points
    - Preliminary Results
Authors: Bocchialini, K.; Koutchmy, S.; Vial, J. -C.; Zirker, J. B.
Bibcode: 1994emsp.conf..173B
Altcode:
  No abstract at ADS

Title: Round Table on Solar Databases
Authors: Vial, J. -C.
Bibcode: 1994emsp.conf..203V
Altcode:
  No abstract at ADS

Title: Congrès Européen de Physique Solaire de Catane (Sicile).
Authors: Vial, J. -C.
Bibcode: 1993LAstr.107..316V
Altcode:
  Conference on «Progrès en physique solaire», Catane (Italy), 11 -
  15 May 1993.

Title: Structure of coronal rays
Authors: Vial, J. -C.; Molodenskij, M. M.
Bibcode: 1993AZh....70.1092V
Altcode:
  The ray structures of the corona are treated as folds and plies of
  magnetic surfaces with a large gradient of electron density when
  projected to the picture plane. The number of the intersections of
  the rays with an arbitrary closed contour in the projection plane is
  shown to be even. This allows the classification of the singular points
  of the observed structures. Such a classification is performed, and
  results of an analysis of singular points of the corona are presented
  for the period 1936-1984.

Title: Structure of coronal rays
Authors: Vial, J. -C.; Molodenskii, M. M.
Bibcode: 1993ARep...37..551V
Altcode: 1993SvA....37..551V
  No abstract at ADS

Title: Two-dimensional radiative transfer with partial frequency
    redistribution. II. Application to resonance lines in quiescent
    prominences
Authors: Paletou, F.; Vial, J. -C.; Auer, L. H.
Bibcode: 1993A&A...274..571P
Altcode:
  Theoretical emergent profiles in the resonance lines of H I Lyman α,
  Mg II h &amp; k and Ca II H &amp; K formed in quiescent prominences
  are presented. Both partial frequency redistribution effects and
  two-dimensional structure have been included in the calculations. The
  prominence model consists of a static, isobaric and isothermal
  freestanding slab irradiated by realistic chromospheric profiles
  (080-8 observations). We compare the differences between complete (CRD)
  and partial frequency redistribution (PRD). Vertical variations in the
  emergent profiles are displayed, and the importance of the geometrical
  effects is discussed. In addition, we have evaluated both emergent
  profiles for a filament as seen over the disk, and the back-scattered
  radiation towards the chromosphere.

Title: The hydrogen spectrum of model prominences.
Authors: Gouttebroze, P.; Heinzel, P.; Vial, J. C.
Bibcode: 1993A&AS...99..513G
Altcode:
  The emission of hydrogen lines and continua from solar prominences is
  investigated using a set of 140 simple models, covering the range of
  physical conditions usually assumed for these objects. These models
  are plane-parallel, isobaric and isothermal. The computations have been
  carried out using a 20 level plus continuum hydrogen atom, and taking
  into account the effects of partial frequency redistribution in the
  Lyman-alpha and beta lines. The aim of these computations is twofold:
  firstly, to describe the variations of hydrogen lines and continua
  emitted by prominences when physical conditions vary. Secondly, to
  provide observers with some diagnostic tool to interpret data such as
  intensity ratios, line widths, etc... The results of computations are
  given as mixed table-figure panels, each of them corresponding to a
  given model and summarizing the associated physical parameters and
  the principal features of the emitted hydrogen spectrum. Finally,
  for some specific parameters (or couple of parameters), we present
  figures illustrating the variations of these quantities across the
  whole set of models.

Title: SUMER - Solar Ultraviolet Measurements of Emitted Radiation
Authors: Wilhelm, K.; Curdt, W.; Marsch, E.; Schuehle, U.; Gabriel,
   A. H.; Lemaire, P.; Vial, J. -C.; Grewing, M.; Huber, M. C. E.;
   Jordan, S. D.; Poland, A. I.; Thomas, R. J.; Kuehne, M.; Timothy, J. G.
Bibcode: 1993BAAS...25.1192W
Altcode:
  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: 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: Quiet and active solar structures as observed at the bottom
    of the transition region.
Authors: Bocchialini, K.; Vial, Jean-Claude
Bibcode: 1992ESASP.348..197B
Altcode: 1992cscl.work..197B
  The authors present a set of high resolution profiles of H Lyman α
  and β, Mg II h and k, Ca II H and K lines measured simultaneously
  above different solar structures. The large data base provides a
  way of correlating different parameters in the different lines:
  Lα reversal vs intensity, Lα vs Ca K, etc... The authors notice
  that Mg II and Ca II have a similar behaviour, different from Lα
  and β ones. They also discuss two classifications derived from the
  distribution of intensities, from which average (cell, network, plage,
  sunspot) profiles are computed for the 6 lines. They compare the Ca
  K results with the two-dimensional models of Solanki et al. (1991).

Title: Radiative modeling of solar prominences, two-dimensional
    transfer plus partial frequency redistribution.
Authors: Paletou, F.; Vial, Jean-Claude; Auer, L. H.
Bibcode: 1992ESASP.348..225P
Altcode: 1992cscl.work..225P
  The two-dimensional, PRD radiative transfer code of Auer and
  Paletou (1992) has been used to compute the resonance lines of H
  I, Mg II and Ca II in quiescent prominences, which are modeled as
  isothermal freestanding slabs illuminated from the sides as well as
  from below. Partial redistribution (PRD) and 2D effects are evidenced
  and compared to complete redistribution computations for both 1D and
  2D geometries. Important edge variations are fround at the bottom
  and the top that should be observed with a spatial resolution of one
  arcsecond. As in 1D, PRD effects allow for greater penetration of the
  incident radiation into the layer. The 2D code computes both the radial
  emergent intensity and the amount of radiation backscattered into the
  chromosphere. It can, accordingly, be used to estimate the visibility of
  filaments. It will be of special interest to build non-isothermal models
  and compare e.g. the Lyα profiles with the SUMER/SOHO observations.

Title: SUMER: temperatures, densities, and velocities in the outer
    solar atmosphere.
Authors: Lemaire, P.; Wilhelm, K.; Axford, W. I.; Curdt, W.; Gabriel,
   A. H.; Grewing, M.; Huber, M. C. E.; Jordan, S. D.; Kuehne, M.;
   Marsch, E.; Poland, A. I.; Richter, A. K.; Thomas, R. J.; Timothy,
   J. G.; Vial, J. C.
Bibcode: 1992ESASP.348...13L
Altcode: 1992cscl.work...13L
  The SUMER instrumentation, that will be mounted on the SOHO spacecraft,
  is in development under MPAE leadership. It has some capability
  to improve the solar angular resolution and the spectral resolution
  already obtained in the far UV to the extreme UV, corresponding to the
  temperature range between 10<SUP>4</SUP> and a few 10<SUP>6</SUP>K. The
  authors give some insights into the SUMER spectrometer that is developed
  to study the dynamics and to infer temperatures and densities of the
  low corona and the chromosphere-corona transition zone in using the
  50 - 160 nm wavelength range. First, they recall the SUMER scientific
  goals and the technics used. Then, after a brief description of the
  instrumentation the expected performances are described. The way the
  observations can be conducted is emphasized and it is shown how SUMER
  is operated in coordination with other SOHO instrumentations and in
  cooperation with ground-based observations.

Title: Structural Characteristics of Eruptive Prominences
Authors: Demoulin, P.; Vial, J. C.
Bibcode: 1992SoPh..141..289D
Altcode:
  Nowadays the primordial importance of the magnetic field for coronal
  plasma physics is well known. However, its determination is only made in
  cool regions, mainly the photosphere and prominences. The extrapolation
  to the corona gives some indications of the magnetic structure but is
  not presently sufficiently reliable. So it is important to consider
  all the other observable physical effects of the magnetic field.

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: "SUMER" - Solar Ultraviolet Measurements of Emitted Radiation.
Authors: Wilhelm, K.; Axford, W. I.; Curdt, W.; Gabriel, A. H.;
   Grewing, M.; Huber, M. C. E.; Jordan, S. D.; Kühne, M.; Lemaire, P.;
   Marsch, E.; Poland, A. I.; Richter, A. K.; Thomas, R. J.; Timothy,
   J. G.; Vial, J. C.
Bibcode: 1992eocm.rept..225W
Altcode:
  The experiment Solar Ultraviolet Measurements of Emitted Radiation
  (SUMER) is designed for the investigations of plasma flow
  characteristics, turbulence and wave motions, plasma densities
  and temperatures, structures and events associated with solar
  magnetic activity in the chromosphere, the transition zone and the
  corona. Specifically, SUMER will measure profiles and intensities
  of extreme ultraviolet (EUV) lines emitted in the solar atmosphere
  ranging from the upper chromosphere to the lower corona; determine line
  broadenings, spectral positions and Doppler shifts with high accuracy;
  provide stigmatic images of selected areas of the Sun in the EUV with
  high spatial, temporal and spectral resolution and obtain full images of
  the Sun and the inner corona in selectable EUV lines, corresponding to a
  temperature range from 10<SUP>4</SUP> to more than 1.8×10<SUP>6</SUP>K.

Title: The fine structure of prominences.
Authors: Heinzel, P.; Vial, J. -C.
Bibcode: 1992ESASP.344...57H
Altcode: 1992spai.rept...57H
  Ground-based observations evidence in prominences a fine structure both
  in density and velocity fields at a subarcsec scale. The modeling of
  such structures is necessary in order to account for heating and cooling
  processes which depend critically on the geometry and the structure of
  the magnetic field. For a rigorous treatment of the radiative losses,
  one needs to solve the full NLTE problem especially in UV lines,
  which are critical for the energy balance. Although some attempts
  have already been made to model individual fine-structure elements,
  quiescent prominences are still mostly considered as one-dimensional
  structures. We discuss current improvements such as two-dimensional
  geometry and bundle of threads.

Title: Evidence of plasmoid ejection in the corona from 1991 eclipse
    observations with the Canada-France-Hawaii telescope
Authors: Vial, J. -C.; Koutchmy, S.; Monnet, G.; Sovka, J.; Clark,
   C.; Salmon, D.; Purves, N.; Sydserff, P.; Coulder, R.; November, L.
Bibcode: 1992ESASP.344...87V
Altcode: 1992spai.rept...87V
  Observations of the solar corona with a large telescope at high
  altitude was fully exploited with the 3.60 m CFHT (Canada France
  Hawaii Telescope) in Hawaii, during the 11 Jul. 1991 eclipse,
  are reported. Different instruments set up for the eclipse and
  preliminary results are given. The moving feature in the corona is
  focused upon. Physical conditions in this plasmoid and its origins
  are discussed. One of the four cameras installed in the primary focus
  was a video charge coupled device camera with a red filter at 637
  nm selecting the red line. The power of the telescope allowed for a
  good signal in a pixel as small as 0.12 arcsec and a very good time
  resolution. The spectral resolution as measured at the Moon limb
  was better than one arcsec. During the three minute long sequence,
  6000 video images were obtained. Among the fine structures recorded,
  a plasmoid about 1500 km wide was seen to ascend and dilute in the
  corona. Possible emission mechanisms are discussed. It was found that
  both low and relatively high temperature plasmas can be confined in this
  ejected plasmoid. Such a small scale phenomenon could be important for
  the heating of the corona and should be observed in UV emission lines
  in a wide range of temperatures. The high spatial resolution achieved
  by Solar Interferometric Mission for Ultrahigh Resolution Imaging and
  Spectroscopy (SIMURIS) allows to study the shape, stability and the
  diagnostics of such plasmoids in the corona.

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: SUMER - Solar ultraviolet measurements of emitted radiation
Authors: Wilhelm, K.; Axford, W. I.; Gurdt, W.; Marsch, E.; Richter,
   A. K.; Grewing, M.; Gabriel, A. H.; Lemaire, P.; Vial, J. -C.; Huber,
   M. C. E.
Bibcode: 1992sws..coll..129W
Altcode:
  The SUMER (solar ultraviolet measurements of emitted radiation)
  experiment is described. It will study flows, turbulent motions, waves,
  temperatures and densities of the plasma in the upper atmosphere of
  the Sun. Structures and events associated with solar magnetic activity
  will be observed on various spatial and temporal scales. This will
  contribute to the understanding of coronal heating processes and the
  solar wind expansion. The instrument will take images of the Sun in EUV
  (extreme ultraviolet) light with high resolution in space, wavelength
  and time. The spatial resolution and spectral resolving power of the
  instrument are described. Spectral shifts can be determined with
  subpixel accuracy. The wavelength range extends from 500 to 1600
  angstroms. The integration time can be as short as one second. Line
  profiles, shifts and broadenings are studied. Ratios of temperature
  and density sensitive EUV emission lines are established.

Title: A solar interferometric mission for ultrahigh resolution
imaging and spectroscopy: SIMURIS
Authors: Damé, L.; Acton, L.; Bruner, M.; Connes, P.; Cornwell, T.;
   Foing, B. H.; Heyvaerts, J.; Lemaire, P.; Martić, M.; Muller, R.;
   Porteneuve, J.; Roca Cortés, T.; Riehl, J.; Rutten, R.; Séchaud,
   M.; Smith, P.; Thorne, A. P.; Title, A. M.; Vial, J. -C.; Visser,
   H.; Weigelt, G.
Bibcode: 1991AdSpR..11a.383D
Altcode: 1991AdSpR..11..383D
  SIMURIS is an interferometric investigation of the very fine structure
  of the solar atmosphere from the photosphere to the corona. It was
  proposed to ESA /1/, November 30 1989, for the Next Medium Size
  Mission - M2, and accepted in February 1990 for an Assessment Study
  in the context of the Space Station. The main scientific objectives
  will be outlined, and the ambitious model payload featuring the Solar
  Ultraviolet Network (SUN), a 2 m long monolithic array of 4 telescopes
  of Ø20 cm, and the Imaging Fourier Transform Spectrometer (IFTS),
  an UV and Visible Imaging Fourier Transform Spectrometer coupled to
  a Ø40 cm Gregory, described.

Title: Solar physics at ultrahigh resolution from the space station
    with the Solar Ultraviolet Network (SUN)
Authors: Damé, L.; Acton, L.; Bruner, M.; Connes, P.; Cornwell,
   T.; Foing, B.; Heyvaerts, J.; Lemaire, P.; Martić, M.; Muller, R.;
   Roca Cortés, T.; Riehl, J.; Rutten, R.; Title, A. M.; Vial, J. -C.;
   Visser, H.; Weigelt, G.
Bibcode: 1991AdSpR..11e.267D
Altcode: 1991AdSpR..11..267D
  The SUN experiment is a UV and visible Space Interferometer aimed at
  ultra-high resolution in the solar atmosphere. It has been proposed
  to ESA as part of the SIMURIS Mission Proposal which has recently
  been accepted for an Assessment Study in the framework of the
  Space Station. The 4 × 20 cm telescopes of the SUN linear array are
  non-redundantly placed to cover a 2 m baseline, and the instrument makes
  full use of stabilized interferometry potential, the 4 telescopes being
  co-aligned and co-phased on a reference field on the sun. After a brief
  outline of the scientific objectives, the concept of the instrument
  is described, and its image reconstruction potential is illustrated.

Title: The helioseismology experiment on the Phobos planetary
    mission. Preliminary results
Authors: Frohlich, C.; Bonnet, R. M.; Bruns, A. V.; Vial, J. C.;
   Delaboudiniere, J. P.; Domingo, V.; Kollath, Z.; Kotov, V. A.;
   Rachkovskii, D. N.; Wehrli, Ch.; Toulain, T.; Shumko, S. M.
Bibcode: 1991BCrAO..83...18F
Altcode:
  No abstract at ADS

Title: Chauffage de la couronne et de la région de transition
    (solaires).
Authors: Vial, J. -C.
Bibcode: 1991sed..conf..317V
Altcode:
  Contents: (1) Evidence d'une région externe chaude et morphologie
  de la couronne solaire. (2) Bilan énergétique. (3) Les sources
  d'énergie. (4) Couronne solaire/couronnes stellaires.

Title: The helioseismological experiment at the Phobos interplanetary
    station - Preliminary results
Authors: Froehlich, C.; Bonnet, R. M.; Bruns, A. V.; Vial, J. C.;
   Delaboudiniere, J. P.; Domingo, V.; Kollath, Z.; Kotov, V. A.;
   Rachkovskii, D. N.; Wehrli, Ch.
Bibcode: 1991IzKry..83...22F
Altcode:
  Preliminary results obtained from IPHIR (Interplanetary Helioseismology
  by Irradiance Measurements), a solar irradiance experiment on board
  the Soviet planetary mission Phobos-2, are presented. During the
  spacecraft's flight to Mars, the instrument gathered valuable data on
  tiny variations of solar irradiance over the course of six months. The
  data clearly show 5-min oscillations with relative amplitudes of about
  10 exp -5 and with a well-defined pattern of discrete peaks in the
  power spectrum. The data of the red channel (it exhibited the lowest
  degradation of sensitivity over time) reveal remarkable temporal changes
  of amplitudes of discrete peaks within a period range of about 5 min,
  but with excellent frequency stability.

Title: UV solar reflecting coronagraph
Authors: Smartt, R. N.; Koutchmy, S.; Vial, J. C.
Bibcode: 1990AIPC..207..578S
Altcode: 1990am...proc..578S
  A dual-channel reflecting coronagraph is proposed that would provide
  observations of Lα corona and chromosphere, upper transition-region
  phenomena in CIV, and also helioseismology observations in the continuum
  around 166 nm. Each channel would use a 104×104-UV-sensitive CCD
  array. The combined velocity and magnetic field data would link
  events in the chromosphere, the transition region and the corona to
  an elongation of about 2.5 R0. These data would be used to study both
  the global-scale and also the fine-scale properties of the corona in
  terms of the physical processes that deposit energy and momentum in the
  corona. Specific question to be investigated would be the origin and
  morphology of CME's and other coronal transients, sources of coronal
  heating, and the source(s) and dynamics of the coronal wind in the
  inner coronal region.

Title: Coming: 24 hour surveillance of the sun.
Authors: Koutchmy, S.; Vial, J. -C.
Bibcode: 1990Rech...21...10K
Altcode:
  No abstract at ADS

Title: Multi-Thread Structure as a Possible Solution for the L-Beta
    Problem in Solar Prominences
Authors: Vial, J. -C.; Rovira, M.; Fontenla, J.; Gouttebroze, P.
Bibcode: 1990LNP...363..282V
Altcode: 1990IAUCo.117..282V; 1990doqp.coll..282V
  Following the pioneering works of Heasley, Mihalas, Milkey and Poland
  (see e.g. Heasley and Milkey, 1983) who built non LTE onedimensional
  models of solar prominence, much attention has been paid to the
  spectral signatures of the Lyman lines as observed with OSO 8 (Vial,
  1982a). In spite of a better treatment of the frequency redistribution
  and boundary conditions, one-dimensional low-pressure models lead to
  Lyman intensities much lower than observed ones (Heinzel, Gouttebroze
  and Vial, 1987). Different atomic processes of formation of hydrogen
  lines (Cooper, Ballagh and Hubeny, 1988) or the inclusion of a
  Prominence Corona Transition Region or PCTR (Heinzel, Gouttebroze and
  Vial, 1988) have been proposed to explain this discrepancy. We present
  here a different approach where the filamentary nature of prominences
  which provides the hydrogen lines with different opacities, offers
  their photons different escaping possibilities. The thread models
  we use derive from an energy equation where radiative losses are
  balanced by conductive flux (Foutenla and Rovira, 1983, 1985). We
  show that no superposition of threads gives good values of Lyman a,
  and H a intensities for too high and too low pressures. Solutions are
  found for pressure around 0.05-0.1 dyn/cm2 and a number of threads
  between 100 and 400. Two improvements have been performed: first, the
  inclusion of Partial Redistribution leads to a decrease of L (and L)
  intensity and models now require a higher number of threads; second,
  the inclusion of the ambipolar diffusion along the steep temperature
  gradient which changes the hydrogen ionization in the lower regions
  (Foutenla, Avrett and Loeser, 1990). The new run of temperature and
  density implies more material at low temperatures and hydrogen lines
  intensities increase. A solution for the L problem can be found for
  a pressure of about 0.1 dyn cm-t2. However the H intensity appears to
  be rather high. Moreover, the number of threads required (about 200)
  is far larger than the number derived by Zirker and Koutchmy (this
  issue) and Mein (this issue) from observed H profiles. Our neglect
  of the radiative interaction between threads may explain our results
  (Heinzel, this issue). To conclude, these computations of non-lte
  radiative transfer in realistic geometrical and physical models, appear
  to be a promising path for the investigation of solar prominences.

Title: High Resolution Solar Physics from the Space Station with
Interferometric Techniques: The Solar Ultraviolet Network (SUN) -
    Instrument &amp;Objectives
Authors: Damé, L.; Acton, L.; Bruner, M.; Connes, P.; Cornwell, T.;
   Foing, B.; Heyvaerts, J.; Jalin, R.; Lemaire, Ph.; Martic, M.; Moreau,
   B.; Muller, R.; Roca Cortés, T.; Riehl, J.; Rutten, R.; Title, A. M.;
   Vial, J. -C.; Visser, H.; Weigelt, G.
Bibcode: 1990PDHO....7..262D
Altcode: 1990dysu.conf..262D; 1990ESPM....6..262D
  No abstract at ADS

Title: The Prominence / Corona Interface
Authors: Vial, J. -C.
Bibcode: 1990LNP...363..106V
Altcode: 1990IAUCo.117..106V; 1990doqp.coll..106V
  The existence of cool and dense material in the hot and diluted corona
  implies specific mass and energy transfers between the two media. This
  is true for all steps in prominence lifetime : formation, quiescence
  and disappearance. Much theoretical work has been done recently on the
  formation by coronal condensation, but observational signatures are
  scarce, probably because of the long duration involved. On the contrary,
  the Disparition Brusque phenomenon has been observed in different
  wavelengths (temperatures) and shown to be either essentially magnetic
  or thermal. Line ratios have been used for the density diagnostics
  of eruptive prominences and point to a small filling factor. As
  for the quiet PCTR, the increase of Differential Emission Measure
  at lower temperatures, extensively studied with Skylab, is still a
  puzzle. With the help of both u-v (HRTS) and radio (VLA) new data,
  temperature gradients have been derived. The DEM increase could be
  explained by such heating process as waves or transients and also
  (at low temperature) by the reduction of radiative losses in optically
  thick lines. UVSP,observations on SMM indicate upflows and downflows
  in the PCTR. Their positions with respect to the magnetic field
  lines are unknown simply because no magnetic measurement exists in the
  PCTR. There is much activity in modeling prominences as a superposition
  of fine structures (threads, loops,..) in thermal equilibrium and in
  comparing with the uv emission. Obviously, we now have some information
  on pressure and temperature gradient in the PCTR but we do not know the
  geometry, the magnetic field nor the heating process. Further decisive
  progress will be made with the spectrometers and coronagraphs on SOHO.

Title: Comparison of Ly-α and Ly-β interplanetary glows observed
    by the Voyager ultra-violet spectrometer.
Authors: Chassefiere, E.; Lallement, R.; Bertaux, J. L.; Vial, J. C.;
   Sandel, B. R.
Bibcode: 1990phoh.coll...65C
Altcode:
  The comparison between Ly-α and Ly-β glows exhibits significant
  discrepancies which can not be explained by radiation transfer in
  the Ly-α interplanetary line. They might be due, at least partially,
  to the temporal variability of the solar flux, larger at Ly-α center
  than at Ly-β center.

Title: Fine structure observation in a solar prominence
Authors: Lemaire, P.; Samain, D.; Vial, J. C.
Bibcode: 1990AdSpR..10i.191L
Altcode: 1990AdSpR..10..191L
  The high resolution balloon spectrograph (RASOLBA) has obtained
  ultraviolet prominence spectra during its September 19th, 1986,
  flight. The high resolution spectra (one arcsecond along the
  30 arcseconds spectrograph slit length, and 0.0015 nm spectral
  resolution within the 20 nm wavelength band) have been recorded on
  film. The wavelength band was centered on the Mgll h and k (279.6
  nm and 280.3 nm) resonance doublet lines inside the cross-dispersion
  echelle spectrograph. <P />The analysis of the prominence spectra shows
  evidence of sheared velocities (up to 20 km/s) which very within few
  arcseconds with the distance above the limb. This shear may appear
  inside magnetic loops confining the prominence material. We present
  the observations and a preliminary analysis of the data.

Title: Le Soleil 24 Heures Sur 24
Authors: Koutchmy, S.; Vial, J.
Bibcode: 1990Rech..217...10K
Altcode:
  No abstract at ADS

Title: Réunion "SOHO-Couronne" des investigateurs français sur
    les instruments coronaux de SOHO.
Authors: Vial, J. C.
Bibcode: 1989JAF....35...18V
Altcode:
  No abstract at ADS

Title: 6 - 20 mars 1989: deux semaines d'intense activité pour une
    seule région solaire.
Authors: Vial, J. -C.
Bibcode: 1989LAstr.103..203V
Altcode:
  No abstract at ADS

Title: Protuberanzen und Beobachtungsprogramme.
Authors: Malherbe, J. -M.; Martres, M. -J.; Vial, J. -C.
Bibcode: 1989Sonne..13....8M
Altcode:
  No abstract at ADS

Title: SUMER - Solar ultraviolet measurements of emitted radiation.
Authors: Curdt, W.; Wilhelm, K.; Axford, W. I.; Marsch, E.; Richter,
   A. K.; Gabriel, A. H.; Lemaire, P.; Vial, J. -C.; Grewing, M.; Huber,
   M. C. E.; Jordan, S. D.; Poland, A. I.; Thomas, R. J.; Timothy, J. G.
Bibcode: 1989AGAb....2...14C
Altcode: 1989amt..conf...14C
  No abstract at ADS

Title: Multithread Structure as a Possible Solution for the L-beta
    Problem in Solar Prominences
Authors: Vial, J. C.; Rovira, M.; Fontela, J.; Gouttebroze, P.
Bibcode: 1989HvaOB..13..347V
Altcode:
  No abstract at ADS

Title: Particles and energy transport in the solar atmosphere during
    solar flares.
Authors: Heristchi, D.; Raadu, M. A.; Vial, J. -C.; Malherbe, J. -M.
Bibcode: 1989sasf.confP.321H
Altcode: 1988sasf.conf..321H; 1989IAUCo.104P.321H
  The proposed model of particle transport in the solar atmosphere
  during flares consists in a low density plasmoid originating
  deep in the atmosphere and rising under magnetic and buoyancy
  forces. Confined particles are selectively released during the ascent
  and their interaction with the solar atmosphere produces X and γ
  bremsstrahlung. The characteristics of high energy particles released
  in the interplanetary medium are found to agree with observations.

Title: The diagnostic and modelling of the solar atmosphere through
non-LTE radiative transfer: some results and prospects.
Authors: Gouttebroze, Pierre; Vial, Jean-Claude; Lemaire, P.
Bibcode: 1989mse..proc..245G
Altcode:
  The authors describe new results from non-LTE radiative transfer
  calculations for solar UV continua and line profiles. The new non-LTE
  codes include partial frequency redistribution in the lines, moving
  atmospheres with differential velocities, and can treat finite objects
  with external irradiation (loops, prominences). Selected examples are
  given for: (1) a static atmosphere (plage); (2) a moving atmosphere
  (waves); and (3) free standing slabs (prominences).

Title: IPHIR: The helioseismology experiment on the PHOBOS mission.
Authors: Fröhlich, C.; Bonnet, R. M.; Bruns, A. V.; Delaboudinière,
   J. P.; Domingo, V.; Kotov, V. A.; Kollath, Z.; Rashkovsky, D. N.;
   Toutain, T.; Vial, J. C.; Wehrli, C.
Bibcode: 1988ESASP.286..359F
Altcode: 1988ssls.rept..359F
  IPHIR (InterPlanetary Helioseismology by IRradiance measurements) is
  a solar irradiance experiment on the USSR planetary mission PHOBOS to
  Mars and its satellite Phobos. The experiment is a cooperative effort
  of PMOD/WRC, LPSP, SSD/ESA, KrAO and CRIP. The sensor is a three channel
  sunphotometer (SPM) which measures the solar spectral irradiance at 335,
  500 and 865 nm with a precision of better than 1 ppm. A two axis solar
  sensor (TASS) is added to monitor the moderate solar pointing of the
  spacecraft. A microprocessor based data processing unit controls the
  sensor operation, acquires the data, and performs the data compression
  for the transmission at a mean rate of 1 bit/s. The two spacecrafts
  have been launched on July 7th and 12th, 1988. The experiment on
  PHOBOS I gathered data during 45 days before the S/C was lost, the
  one on PHOBOS II is still operating. The data recovery is excellent
  with virtually 100% coverage. Although the signal is disturbed by the
  pointing of the spacecraft the results of a preliminary analysis in
  the range of the 5-minutes oscillations demonstrate the improvement
  achievable due to the fact that the time series is truly continuous
  and the instrumental and sampling noise is very low.

Title: Non LTE modelling of prominences.
Authors: Heinzel, P.; Gouttebroze, P.; Vial, J. -C.
Bibcode: 1988dssp.conf...71H
Altcode:
  The authors present the results on non-LTE computations performed in
  the major lines and continua of the hydrogen atom. The prominence is
  represented by a slab illuminated by the neighbouring chromosphere and
  corona. Classical models are recomputed and it appears that the low
  pressure model represent well the observed Lα profiles. However the
  Lβ-computed value is much lower than the observed one. Preliminary
  computations where a transition region to the corona is included that
  the Lβ line may be improved.

Title: Two Solar Observation Programmes
Authors: Marthes, M. J.; Malherbe, J. M.; Vial, J.
Bibcode: 1988scaa.conf..175M
Altcode: 1988IAUCo..98..175M
  No abstract at ADS

Title: The O VI (103.2 nm) prominence profile and the
    prominence-corona interface.
Authors: Vial, J. -C.
Bibcode: 1988dssp.conf..181V
Altcode:
  Few lines profiles have been obtained up-to-now in the transition region
  between prominences and corona (PCTR hereafter). The major source of
  information has been Skylab UV intensities. Important results concern:
  the presence of cool absorbing material as in the corona, the evidence
  of numerous (about 8) PCTRs, the similarity between differential
  emission measures of the chromosphere-corona transition region and
  the PCTR, especially in increase towards lower temperatures. However
  in the absence of profiles measurements, the run of temperature,
  densities and microturbulence could not be derived in the PCTR.

Title: Formation of the hydrogen spectrum in quiescent prominences -
    One-dimensional models with standard partial redistribution
Authors: Heinzel, P.; Gouttebroze, P.; Vial, J. -C.
Bibcode: 1987A&A...183..351H
Altcode:
  One-dimensional isothermal-isobaric static slab models are used to study
  departures from complete frequency redistribution (CRD) in hydrogen
  lines for quiescent solar prominences. Partial redistribution (PRD)
  effects on the hydrogen L-alpha line are shown to be significant
  in the near wings in addition to the far wings of L-alpha. It is
  suggested that strong symmetrical peaks found in the theoretical
  PRD L-alpha profiles are due to partially coherent penetration of
  the incidence double-peaked solar L-alpha. The present results are
  found to be consistent with OSO-8/LPSP observations and with UVSP/SMM
  data. The possible interplay between the effects of lateral transport
  or radiation, level-interlocking, and PRD is considered.

Title: Protubérances solaires et programmes d'observation.
Authors: Malherbe, Jean-Marie; Martres, Marie-Josephe; Vial,
   Jean-Claude
Bibcode: 1987LAstr.101..321M
Altcode:
  The observed characteristics of solar prominences are reviewed, and
  models for the formation of filaments and for the magnetic structure
  of protuberances are discussed. Data suggest that coronal filaments
  are formed either by the pumping of chromospheric matter or by
  condensation of the coronal plasma itself by thermal instability. The
  class of Kippenhahn-Schluter models involve magnetic rings which are
  bent under the influence of gravity, and the class of Kuperus-Raadu
  models place prominences above a certain neutral point. Observations
  of filamentary velocity fields indicate that the magnetic support of
  the condensation is in quasi-static evolution. Three proposed areas
  of study of prominences, the connections and exchanges of matter at
  great distances, eruptive prominences, and the sudden disappearance
  of prominences, are discussed.

Title: Structures fines chromosphériques: nouveaux résultats de
    la caméra de la région de transition.
Authors: Foing, B. H.; Dame, L.; Vial, J. C.; Gouttebroze, P.; Martic,
   M.; Bonnet, R. M.
Bibcode: 1987JAF....29...15F
Altcode:
  No abstract at ADS

Title: La haute résolution en physique solaire: perspectives pour
    l'avenir.
Authors: Damé, L.; Foing, B.; Vial, J. C.
Bibcode: 1987JAF....29...16D
Altcode:
  No abstract at ADS

Title: Simultaneous measurements of chromospheric lines in sunspot
    umbra andpenumbra.
Authors: Vial, J. -C.; Bellout, A.
Bibcode: 1987PAICz..66..215V
Altcode: 1987eram....1..215V
  The author reports on simultaneous profiles measurements obtained in
  the Lα, Lβ, Mg II and Ca II lines in a sunspot umbra and penumbra,
  performed with the L.P.S.P. instrument on OSO 8. They aim at providing
  some new information on both oscillations and thermodynamic structure
  of sunspots.

Title: The OVI 103.2-NM Prominence Profile and the Prominence /
    Corona Interface
Authors: Vial, J. C.
Bibcode: 1987dssp.work..181V
Altcode: 1987ASSL..150..181V
  No abstract at ADS

Title: Non-Lte Modelling of Prominences
Authors: Heinzel, P.; Gouttebroze, P.; Vial, J. C.
Bibcode: 1987dssp.work...71H
Altcode: 1987ASSL..150...71H
  No abstract at ADS

Title: Observations spatiales solaires.
Authors: Vial, J. C.
Bibcode: 1987JAF....29...15V
Altcode:
  No abstract at ADS

Title: Diagnostics and structure.
Authors: Vial, J. C.
Bibcode: 1986NASCP2442...89V
Altcode:
  The structure of prominences and the diagnostic techniques used to
  evaluate their physical parameters are reviewed and discussed.

Title: Partial redistribution effects in the formation of hydrogen
    lines in quiescent prominences.
Authors: Heinzel, P.; Gouttebroze, P.; Vial, J. C.
Bibcode: 1986NASCP2442..155H
Altcode: 1986copp.nasa..155H
  Departures from complete frequency redistribution (CRD) in hydrogen
  lines are investigated for solar prominences. Partial redistribution
  effects (PRD) are found both in the wings (their already known lowering)
  and in the central part of the L alpha line; a new feature is evidenced
  here: the partially coherent scattering in the near wings of the
  line leads to a double-peaked profile mirroring the incident solar
  radiation. With a low density model, we obtain a good agreement with
  OSO 8 observed profiles. On the contrary, the PRD computed L beta
  profile (lower density, no reversal) departs from the observed one,
  a result which calls for more progress in terms of non-LTE transfer
  and modelling.

Title: Dynamical properties of a pre-perihelion comet
    tail. I. December 6, 1985 observations of P/Halley 82i.
Authors: Guerin, P.; Koutchmy, S.; Vial, J. C.
Bibcode: 1986A&A...167..395G
Altcode:
  Wide field pictures of comet P/Halley 1982i obtained every hour on
  December 6, 1985, have been analyzed in order to study the dynamics
  of low intensity plasma structures in the tail. The deduced radial
  velocities increase from 50 to 80 km s<SUP>-1</SUP> over distances
  of 2 to 6×10<SUP>6</SUP>km. The measured apparent aberration angle
  is interpreted as a result of a large polarward solar wind velocity
  component.

Title: Non-LTE models of solar prominences
Authors: Heinzel, P.; Vial, J. C.; Gouttebroze, P.; Rompolt, B.
Bibcode: 1986CoSka..15..183H
Altcode:
  The authors briefly review some representative non-LTE models of solar
  prominences, developed during the past decade. Particular attention is
  devoted to recent interpretation of hydrogen Lyman α line profiles
  in quiescent prominences and to the solution of the non-LTE problem
  for moving active prominences. Finally, the authors outline some of
  the most important prospects of prominence plasma diagnostics.

Title: Emission of Lyman alpha radiation by solar coronal loops. I -
    General synopsis
Authors: Gouttebroze, P.; Vial, J. C.; Tsiropoula, G.
Bibcode: 1986A&A...154..154G
Altcode:
  The processes of emission of Lyman-alpha radiation by loop-like
  structures embedded in the solar corona are investigated, for
  a large range of physical conditions within these objects. The
  coupled set of equations for radiative transfer, and hydrogen atom
  level populations, ionization and pressure equilibria is solved
  to obtain the emitted L-alpha intensities as functions of pressure,
  temperature and size. Three different cases are treated: (1) optically
  thin structures with arbitrary geometry. (2) plane-parallel slabs,
  either horizontal or vertical, with arbitrary optical depth. (3)
  cylindrical loops with horizontal axis, for moderate optical depths
  (au is less than 1000). The importance of geometry, as well as that of
  partial frequency redistribution and of the hydrogen atom's model, are
  evaluated. Empirical formulae and diagrams of intensity as a function
  of physical state parameters are given. The diagnostic possibilities of
  Lyman-alpha filtergrams alone or in conjunction with other observations,
  are discussed.

Title: On the origin of the blue continuum of white-light flares
Authors: Dame, L.; Vial, J. -C.
Bibcode: 1985ApJ...299L.103D
Altcode:
  A new model for white-light flares is proposed in order to explain
  the observed blue continuum (i.e., the higher contrast longward of
  the Balmer jump, around 4000 A). Its broad temperature plateau between
  60,000 and 90,000 K is compatible with chromospheric evaporation. The
  predicted UV emission, computed here in the Si IV resonance lines
  (1402 and 1393 A), is, however, too large by two orders of magnitude,
  as compared to the emission from weak flares. Because of the lack of a
  comprehensive set of measurements in white-light flares, the validity
  of such a model is still open.

Title: Periodic Comet Halley (1982i)
Authors: Jewitt, D.; Meech, K.; Ricker, G.; Lamy, P.; Koutchmy, S.;
   Vial, J. C.
Bibcode: 1985IAUC.4148....1J
Altcode:
  D. Jewitt, K. Meech, and G. Ricker, Massachusetts Institute of
  Technology, communicate: "Observations from McGraw-Hill Observatory
  on Kitt Peak over 4 nights show variable structures in the inner
  coma of P/Halley. Images were taken through broad and narrowband
  interference filters using the MIT 'MASCOT' CCD camera on the 1.3-m
  telescope. Jet-like structures were observed in position angles 358
  and 313 on Nov. 29 UT. The jets extended 10 000 km in the plane of
  the sky and had widths comparable to the atmospheric seeing. The
  jets were visible in both broad and narrowband continuum filters and
  are probably dust features. The jets showed no variation in position
  angle or brightness in an observing interval of &gt; 3 hr but were
  absent on the preceding and following nights." Meech and Jewitt also
  report: "Observations of P/Halley with the Kitt Peak 0.61-/0.91-m
  Schmidt telescope (with baked IIIa-J plates and exposure times
  30-60 min) show that extensive tail development has occurred within
  the past month. Observations on Nov. 6-9 showed only a transient,
  faint anti-solar tail (length 20' on Nov. 6.20) which faded in &lt;
  1 day. Observations on Dec. 4-8 show a persistent plasma tail (length
  &gt; 2.5 deg) displaying a classical streamer morphology. We are able
  to follow knots, kinks, and streamers in the tail for up to 6 hr. The
  measured speeds of 3 tail knots are 190, 216, and 240"/hr (39, 45, and
  50 +/- 5 km/s along the tail, km/s), considerably less than the solar
  wind speed but similar to the speeds measured in the tails of other
  comets. No evidence for acceleration of the features is seen. Two
  episodes of ray formation have been seen in 25 hr of observation;
  the rays form in ~ 1 hr and evolve over several hr, but fade in &lt;
  18 hr. The tail as a whole shows gross brightness changes from night
  to night. No dust tail is seen." P. Lamy, Laboratoire d'Astronomie
  Spatiale, Marseille, and S. Koutchmy, Institut d'Astrophysique, Paris,
  telex: "Four consecutive 1-hr-exposure IIIa-J hypered plates obtained
  between Dec. 6.79-6.96 UT by Koutchmy and J. C. Vial with the 0.62-m
  f/3 Schmidt telescope of Haute Provence Observatory show a disturbed,
  narrow, plasma tail of length &gt; 2 deg. The tail's inner part
  deviates southward from the anti-solar direction by 4.8 +/- 0.7 deg;
  the outer part widens and nears the anti-solar direction. The point
  of bifurcation seems to move radially outward with time."

Title: Transfer of Lyman-α radiation in solar coronal loops.
Authors: Gouttebroze, P.; Vial, J. -C.; Tsiropoula, G.
Bibcode: 1985ASIC..152..359G
Altcode: 1985pssl.proc..359G
  The emission and scattering of Lyman-α radiation within the loop-like
  structures of the solar corona are investigated, for a large range
  of physical conditions within these objects. Results from partial
  and complete redistribution computations are compared. A series of
  predictions, concerning line profiles, integrated intensities, and
  directional diagrams are given for observation diagnosis.

Title: Le satellite S.M.M. (Solar Maximum Mission). Un observatoire
    tout entier consacré à l'activité solaire.
Authors: Vial, J. -C.
Bibcode: 1984LAstr..98..211V
Altcode:
  The instrumentation on-board the SMM is described, together with
  data gathered up to November 1980. The SMM carries a gamma ray
  spectrometer, two hard X ray spectrometers, an X ray polychromator,
  an UV spectrometer polarimeter, a coronograph/polarimeter and a
  radiometer. The observational data linked the eruption processes
  with the appearance of parasitic magnetism, the disappearance of a
  filament, plasma temperature enhancement to 50,000 K, an increase in
  the 6 cm flux continuum and hard X ray emission. Measurements have
  confirmed a two-stage flux acceleration, with highest temperatures
  happening before peak emissions. The deeper understanding of solar
  flux phenomena gained with the SMM has been due in large part to an
  internationally cooperative effort to confirm space-based observations
  with ground-based measurements.

Title: Simultaneous H and K Ca  ii, h and k Mg  ii, Lα and Lβ
    H  i profiles of the April 15, 1978 solar flare observed with the
    OSO-8/L.P.S.P. experiment
Authors: Lemaire, P.; Choucq-Bruston, M.; Vial, J. -C.
Bibcode: 1984SoPh...90...63L
Altcode:
  Solar flare observations have been performed with the multichannel
  L.P.S.P. experiment on board OSO-8 NASA Satellite. Simultaneous H and K
  CaII, h and k MgII, Lα and Lβ HI profiles have been recorded on the
  plage just before the flare, during the flare onset and relaxation
  phases. The different behaviour of line profiles and intensities
  during the flare is evidenced and indicates a downward propagation
  with relaxation times increasing from the upper part to the lower part
  of the chromosphere related to line formation processes. Using the Hɛ
  observed profile, an upper limit of 8 × 10<SUP>13</SUP> cm<SUP>-3</SUP>
  is derived for the electron density.

Title: Simultaneous H and K CAII H and K MGII L-Alpha L-Beta HI
    Profiles of a Solar Flare Observed with OSO-8 L.P.S.P. Spectrometer
Authors: Lemaire, P.; Choucq-Bruston, M.; Vial, J. C.
Bibcode: 1984apoa.conf..266L
Altcode:
  No abstract at ADS

Title: Dynamics of a surge observed in the C IV and H alpha lines
Authors: Schmieder, B.; Mein, P.; Vial, J. -C.; Tandberg-Hanssen, E.
Bibcode: 1983A&A...127..337S
Altcode:
  Time sequences of a surge have been obtained in Active Region 2701
  during a coordinated SMY program, on October 2nd, 1980, while the MSDP
  spectrograph operated in H-alpha at the Meudon Solar Tower and the UVSP
  spectrometer on SMM observed in the 1548 A C IV resonance line. The cold
  (H-alpha) and hot (C IV) material follow the same channel, and the event
  lasts about 10 min in both lines. A good correlation is found between
  H-alpha and C IV velocities; radial velocities along the surge are in
  the range 40-60 km/s in both cases. The observations are consistent
  with the hypothesis that a pressure gradient drives the surge. The
  H-alpha data seem to indicate the presence of a shock wave in the
  chromosphere, while the C IV quantities (velocities, accelerations)
  vary on a very short time scale. Their maxima occur at some locations
  which could be interpreted as 'pinched' zones.

Title: OSO-8 observations of a quiescent prominence - A comparison
    of Lyman-alpha with theoretical intensities
Authors: Heinzel, P.; Vial, J. -C.
Bibcode: 1983A&A...121..155H
Altcode:
  Using simultaneous observations of hydrogen Lyman-α and Ca II K lines
  obtained with the OSO 8 LPSP instrument, the authors compare Lα
  emission from a quiescent prominence with those predicted from the
  existing theoretical models. They use the observed relation between
  Hα and Ca II K integrated intensities to obtain an estimate of
  E(Hα)/E(Lα) vs. E(Hα). This ratio differs significantly from those
  predicted theoretically under the assumption of complete frequency
  redistribution during the scattering of Lα photons. On the other
  hand, using the partial-redistribution treatment in the Lα wings,
  as suggested by Milkey et al., the authors arrived at a reasonable
  agreement with the corresponding theoretical curve. The possible
  influence of macroscopic velocities on line ratios is briefly discussed.

Title: Structure and Physics of Solar Faculae - Part Three - the
    Densities in the Chromosphere-Corona Transition Zone
Authors: Dumont, S.; Mouradian, Z.; Pecker, J. -C.; Vial, J. -C.;
   Chipman, E.
Bibcode: 1983SoPh...83...27D
Altcode:
  Si IV, C IV, and O VI resonance lines have been measured above quiet
  and active solar regions from both pointed OSO-8 instruments. From
  calibrated profiles, optical depths are computed with three different
  methods. All three methods provide evidence that the opacity above
  faculae is lower than above the quiet Sun.

Title: Measurements of solar transition zone velocities and line
    broadening using the ultraviolet spectrometer and polarimeter on
    the Solar Maximum Mission
Authors: Simon, G.; Mein, P.; Vial, J. C.; Shine, R. A.; Woodgate,
   B. E.
Bibcode: 1982A&A...115..367S
Altcode:
  The UVSP instrument on SMM is able to observe solar regions at two
  wavelengths in the same line with a band-pass of 0.3 A. Intensity and
  Doppler velocity maps are derived. It is shown that the numerical
  values are sensitive to the adopted Doppler width and the range of
  velocities is limited to within 30 km/sec. A method called Double
  Dopplergram Determination (DDD) is described for deriving both the
  Doppler width and the velocity (up to 80 km/sec), and the main sources
  of uncertainties are discussed. To illustrate the method, a set of C
  IV 1548 A observations is analyzed according to this procedure. The
  mean C IV Doppler width measured (0.15 A) is comparable to previous
  determinations. A relation is found between bright regions and
  down-flows. Large Doppler widths correspond to strong velocity
  gradients.

Title: Mass motions in the solar chromosphere and transition zone
Authors: Mein, P.; Simon, G.; Vial, J. C.; Shine, R. A.
Bibcode: 1982A&A...111..136M
Altcode:
  A comparison is made between H-alpha and C IV observations of Active
  Region 2717 on October 9, 1980. On the basis of this comparison,
  it is found that upward velocities are present above sunspots in the
  chromosphere-corona transition zone (20 km/s). The downward velocities
  are found to be well correlated in both lines. Doppler-shift ratios
  between C IV and H-alpha levels (approximately 10) are seen to be much
  smaller than expected from density ratio estimates. The comparison is
  seen as suggesting that flow lines are probably far from vertical in
  the transition zone. It is pointed out, however, that this depends
  on model densities that may not be correct. A simple method for
  comparing matter flows is presented. The best fit between H-alpha and
  C IV levels is obtained when C IV Doppler shifts are multiplied by
  the line intensity to the power 0.5 (approximately) in order to make
  allowance for density fluctuations.

Title: Structure and Physics of Solar Faculae - Part Two - the
    Non-Thermal Velocity Field above Faculae
Authors: Mouradian, Z.; Dumont, S.; Pecker, J. -C.; Chipman, E.;
   Artzner, G. E.; Vial, J. C.
Bibcode: 1982SoPh...78...83M
Altcode:
  The OSO-8 satellite enabled us to study various characteristics of
  the profiles of Si II, Si IV, C IV, and O VI lines above active areas
  of the Sun, as well as above quiet areas, and to derive some physical
  properties of the transition region between chromosphere and corona
  (CCT): (i) The study of the lines shows a general tendency for the
  microvelocity fields on the average to be nearly constant for the
  heights corresponding to T &gt; 10<SUP>5</SUP> K; however they seem
  to slightly increase with height in quiet areas, and decrease in
  active areas. (ii) A multicomponent model of the CCT is however quite
  necessary, and its geometry is far from being a set of plane-parallel
  columns. It is similar to an association of moving knots within the
  non-moving principal component of the matter. (iii) The proportion
  of mass, in the knots relative to that in the non-moving component,
  is several times larger in active regions than in quiet regions. (iv)
  In the knots, the non-thermal microvelocity fields are smaller in active
  regions and seem to decrease for T increasing above 10<SUP>5</SUP> K,
  contrary to what happens in the steady principal component. Of course,
  we consider that microturbulence and Doppler shift are two aspects of
  the same distribution of velocity.

Title: Two-dimensional nonlocal thermodynamic equilibrium transfer
    computations of resonance lines in quiescent prominences
Authors: Vial, J. C.
Bibcode: 1982ApJ...254..780V
Altcode:
  The two-dimensional transfer code of Mihalas, Auer and Mihalas (1978)
  is used to compute emergent profiles of resonance lines of H I, Mg
  II, and Ca II. The model (a uniform slab limited in two directions)
  and the radiative and thermodynamic quantities are described. The
  metallic line profiles are sensitive to the ionization degree, which
  is fixed at a certain value. Some modifications are implemented in
  the code, in particular, the true incident profiles of chromospheric
  lines. A comparison is made between two-dimensional and one-dimensional
  profiles. Good agreement between computed and observed profiles is
  found for Ly-alpha and Ca II but not for Mg II lines.

Title: Optically thick lines in a quiescent prominence - Profiles of
    Lyman-alpha, Lyman-beta /H I/, K and H /Mg II/, and K and H /Ca II/
    lines with the OSO 8 LPSP instrument
Authors: Vial, J. C.
Bibcode: 1982ApJ...253..330V
Altcode:
  The first set of simultaneous measurements are presented of H I
  Lyman-alpha and Lyman-beta, Ca II K and H, and Mg II k and h lines
  in a quiescent prominence. It is found that: (1) Ca II resonance
  lines have low opacity, with an optical thickness at the center of
  the K line varying between 1.4 and 3.2, and nonthermal velocities
  ranging from 5 to 9 km/sec.; (2) the resonance lines of Mg II, as
  measured in the whole prominence, depart from Gaussian profiles and
  are unexplainably broader than the corresponding Ca II ones. The
  observed Mg II and Ca II 'inverted' intensity ratios may be due to
  different incident intensities ratios; and (3) the Lyman-alpha and
  Lyman-beta lines of H I have the same reversals as the chromospheric
  lines in bright regions, and unreversed profiles may be observed in
  darker regions. The intensities are larger than the diluted incident
  radiation, and the opacity reaches values of 100,000.

Title: Preflare heating of filaments
Authors: Malherbe, J. M.; Simon, G.; Mein, P.; Mein, N.; Schmieder,
   B.; Vial, J. C.
Bibcode: 1982AdSpR...2k..53M
Altcode: 1982AdSpR...2...53M
  Disappearances of preflare filaments have been observed on June 22,
  1980 (S07,W13) (flare at 13.04 U.T.) and September 3, 1980 (flare
  at 7.52 U.T.). The analysis of MSDP data (MEUDON) leads to the
  followings conclusions : - Disappearances begin a few minutes before
  the Hα impulsive phase. - The filaments can be seen again after the
  flares. - Upwards motions occur in several points, without disturbing
  significantly preëxisting downflows. <P />Velocity maps suggest shears
  or velocity loops. <P />The filament disappearance seems to be due to
  a heating mechanism beginning before the flare maximum.

Title: A surge obsrved in Hα and CIV
Authors: Schmieder, B.; Mein, P.; Vial, J. C.; Tandberg-Hanssen, E.
Bibcode: 1982AdSpR...2k.225S
Altcode: 1982AdSpR...2..225S
  Simultaneous Hα (MSDP at Meudon) and C IV (UVSP aboard SMM)
  measurements of Active Region 2701 were made on October 2,
  1980. Isodensity and velocity maps were derived for both lines
  and superposed. A good correlation was found between Hα and C IV
  velocities. A surge was observed for 10 minutes. The base was located
  in a bright point in CIV and Hα, and escaping matter followed the same
  channel (``absorbing'' in Hα, ``emitting'' in C IV). The velocity
  along the surge was about 80 kms.-1 in Hα and 100 km s-1 in C IV. A
  loop appeared in C IV. We discuss the existing models and conclude
  that the vertical pressure gradient was capable of driving the surge.

Title: Physical properties of the solar chromosphere deduced from
    optically thick lines. I - Observations, data reduction, and modelling
    of an average plage
Authors: Lemaire, P.; Gouttebroze, P.; Vial, J. C.; Artzner, G. E.
Bibcode: 1981A&A...103..160L
Altcode:
  Simultaneous Ca II H and K, Mg II h and k, and H I Lyman-alpha and
  Lyman-beta profiles have been recorded by the OSO-8/LPSP spectrometer on
  a quiet sun area and a part of plage, McMath 13738. After data reduction
  and filtering, a full set of calibrated profiles is obtained. Using
  a code developed at LPSP (Gouttebroze et al., 1978), profiles
  computed from VAL III model C (Vernazza et al., 1981) are compared
  to observations. A specific plage model has been computed to fit the
  observed profiles. This model reproduces successfully Ca II H and K,
  and H I Lyman-alpha and Lyman-beta, but partly fails with Mg II h and
  k. Atmospheric inhomogeneities and dynamical effects may contribute to
  this discrepancy, and it is proposed that the level number entering
  in the Mg II computation be increased to take account of a likely
  fluorescence induced by the H I Lyman-beta radiation field.

Title: Absorption feature observed on the H Lyman-alpha solar line -
    an interpretation
Authors: Artzner, G.; Cazes, S.; Emerich, C.; Vial, J. C.; Lemaire, P.
Bibcode: 1981A&A...100..205A
Altcode:
  A narrow absorption feature on the red part of the solar H Lyman-alpha
  profile has been observed by two instruments in 1975 and attributed
  to atomic hydrogen of the nearby interplanetary gas. This hypothesis
  implies that the absorption feature shifts with the position of the
  earth on its orbit. New measurements above active regions at other
  seasons rule out this hypothesis. On the other hand, appropriate
  laboratory calibrations indicate that the absorption feature is likely
  due to a ghost image of the geocoronal absorption.

Title: Lα, Lβ (of H i), k and h (of Mg ii), K and H (of Ca  ii)
    observations in a quiescent prominence with the OSO-8 LPSP instrument
Authors: Vial, J. C.; Martres, M. J.; Salm-Platzer, J.
Bibcode: 1981SoPh...70..325V
Altcode:
  A sequence of images taken at different positions in the resonance lines
  of Ca II, Mg II, and H I was obtained over a quiescent prominence
  with the LPSP instrument on OSO-8. Ca II K (and H) profiles are
  reconstructed at different locations in the prominence with a (10 × 5)
  arc sec<SUP>2</SUP> resolution. Significant variations of FWHM and line
  shifts are found: FWHM range from 0.14 Å to 0.5 Å; blue shifts reach
  about 14 km s<SUP>-1</SUP>. The ratio of K to H absolute intensities
  shows a large spread around the average value of 1.2. The same ratio
  for the Mg II lines in the whole prominence is higher (1.7), a fact
  already noticed at the edge of an active prominence (Vial et al.,
  1979). The ionization degree, as measured by the Lα/Ca K ratio, shows
  noticeable variations within the prominence. The Lα intensity is about
  0.3 times the intensity measured in the quiet Sun, and the Lα/Lβ
  ratio is less than one half the disk value. These results indicate
  important variations of the thermal conditions inside the prominence.

Title: OSO-8 Observations of CAII H and K MGII H and K Lyman-Alpha
    and Lyman-Beta above a Sunspot
Authors: Kneer, F.; Scharmer, G.; Mattig, W.; Wyller, A.; Artzner,
   G.; Lemaire, P.; Vial, J. C.
Bibcode: 1981SoPh...69..289K
Altcode:
  Observations with the French (L.P.S.P.) experiment on board OSO-8 of
  a sunspot and nearby plage region are described. The behaviour of the
  emission cores of the Ca II H and K and Mg II h and k resonance lines is
  very similar and the correspondence in intensity between the four lines
  persists in all observed features. In contrast, the Lyman lines show
  little correlation with the other lines. Their emission regions appear
  broader in the spectroheliograms than the underlying sunspot structure
  and must not necessarily possess a counterpart in lower layers. From
  the central intensity of Lα above the umbra an electron density of
  4.3 × 10<SUP>10</SUP> cm<SUP>-3</SUP> ≲n<SUB>e</SUB><SUP>*</SUP>
  ≲2.3 × 10<SUP>11</SUP> cm<SUP>-3</SUP> at 20 000 K is estimated.

Title: Solar H I LY alpha far wing measurement
Authors: Jouchoux, A.; Vial, J. C.; Artzner, G. E.; Gouttebroze, P.;
   Lemaire, P.
Bibcode: 1981A&A....93..415J
Altcode:
  High spectral resolution photoelectric observations of the solar H I
  Ly alpha far wing are presented. Measurements above active regions and
  quiet sun center are compared to photographic observations of Basri
  et al. (1979).

Title: Contribution à l'étude des protubérances solaires à partir
    des observations effectuées sur l'instrument du LPSP à bord du
satellite OSO-8 Title: Contribution à l'étude des protubérances
    solaires à partir des observations effectuées sur l'instrument du
LPSP à bord du satellite OSO-8 Title: Contribution to the study of
    solar prominences from observations made on the LPSP instrument on
    board the OSO-8 satellite;
Authors: Vial, Jean-Claude Jacques
Bibcode: 1981PhDT........42V
Altcode:
  No abstract at ADS

Title: On VI (λ = 1032 Å) profiles in and above an active region
    prominence, compared to quiet Sun center and limb profiles
Authors: Vial, J. C.; Lemaire, P.; Artzner, G.; Gouttebroze, P.
Bibcode: 1980SoPh...68..187V
Altcode:
  O VI (λ = 1032 Å) profiles have been measured in and above a filament
  at the limb, previously analyzed in H I, Mg II, Ca II resonance lines
  (Vial et al., 1979). They are compared to profiles measured at the
  quiet Sun center and at the quiet Sun limb.

Title: Microturbulence near the edge of a solar plage
Authors: Simon, G.; Mouradian, Z.; Dumont, S.; Pecker, J. C.; Artzner,
   G.; Vial, J. C.
Bibcode: 1980A&A....89L...8S
Altcode:
  Observations of the Ca II K line at the edge of a solar plage show
  enhanced separation of the K2 peaks with respect to the measured value
  inside the plage and in the quiet sun. This effect may be interpreted as
  a variation of microturbulent motions at the height of formation of K2.

Title: Observations of Chromospheric Lines from OSO-8
Authors: Grossmann-Doerth, U.; Kneer, F.; Uexkuell, M.; Artzner,
   G. E.; Vial, J. C.
Bibcode: 1980SoPh...66....3G
Altcode:
  The line profiles of Lα, Ca II K and Mg IIk were measured with the
  spectrometer of the `Laboratoire de Physique Stellaire et Planétaire'
  on board of OSO-8. The results of these measurements are presented.

Title: Center-to-limb solar observations of the K<SUB>2</SUB>
    component of the Ca II K line with the OSO 8 satellite.
Authors: Dumont, S.; Mouradian, Z.; Pecker, J. -C.; Simon, G.; Artzner,
   G. E.; Vial, J. C.
Bibcode: 1980CRASB.290..365D
Altcode:
  OSO 8 spectrometer measurements of the separation between emission
  peaks in the K2 Ca II line across the solar disk in quiet and active
  regions are presented. The center-to-limb variation in emission peak
  separation is found to differ slightly for quiet and facula regions
  at distances greater than 0.2 solar radii from the limb, in agreement
  with previous observations. For a facula located at the solar limb,
  however, the peak separation is observed to be up to 35 percent greater
  than in quiet regions, indicating the presence of a region of enhanced
  chromospheric turbulence surrounding the faculae.

Title: Non thermal velocities in the chromosphere-corona transition
    zone of solar active regions.
Authors: Dumont, S.; Mouradian, Z.; Pecker, J. -C.; Chipman, E.;
   Artzner, G.; Vial, J. -C.
Bibcode: 1980CRASB.290..317D
Altcode:
  OSO 8 satellite observations of lines of the Si II, Si IV, C IV and
  O VI ions in the ultraviolet spectrum of active solar regions are
  considered. It is noted that for the case of pronounced physical
  dispersion of the data, there is no marked systematic variation from
  the center to the edge of the solar disk. The nonthermal velocities
  in the transition zone are, for a given temperature, the same as for
  quiet regions. In addition, the velocities tend to reach a constant
  value at temperatures above 100,000 deg K, and the observed physical
  dispersion is much higher than the inaccuracy of the data.

Title: Profiles of H I (Lalpha ), Mg II (h and k), Ca II (H and K)
    lines of an active filament at the limb, with the LPSP instrument
    aboard the OSO-8 satellite.
Authors: Vial, J. C.; Gouttebroze, P.; Artzner, G.; Lemaire, P.
Bibcode: 1979SoPh...61...39V
Altcode:
  We scanned the H I Lα, Mg II h and k, Ca II K and H lines
  simultaneously with the LPSP instrument on OSO-8, to investigate the low
  and moderate temperature regions of an `active region filament'. The
  Lα line is not reversed except for the innermost position in the
  prominence. Intensity (k/h), (K/H) ratios are respectively 2 and 1.1,
  indicating that the Mg II lines are optically thin, and that Ca II
  K is saturated, although not clearly reversed. The results obtained
  during the second sequence of observations (K saturated before Lα
  for example) indicate that within the size of the slit (1″ × 10″)
  we are not observing the same emitting features in the different lines.

Title: LY α and β of hi, H and K of MG ii, H and K of CA II Profiles
    of a Quiescent Prominence Obtained with the LPSP Instrument of OSO-8.
Authors: Vial, J. C.; Lemaire, P.; Gouttebroze, P.
Bibcode: 1979phsp.coll...52V
Altcode: 1979IAUCo..44...52V
  No abstract at ADS

Title: Profiles of H i (Lyα), MG II (h and K), CA II (h and k)
    Lines in an Active Filament at the Limb, Observed with the LPSP
    Instrument Onboard the OSO-8 Satellite.
Authors: Vial, J. C.; Gouttebroze, P.; Artzner, G.; Lemaire, P.
Bibcode: 1979phsp.coll..250V
Altcode: 1979IAUCo..44..250V
  No abstract at ADS

Title: The solar hydrogen Lyman-beta and Lyman-alpha lines: disk
    center observations from OSO 8 compared with theoretical profiles.
Authors: Gouttebroze, P.; Lemaire, P.; Vial, J. C.; Artzner, G.
Bibcode: 1978ApJ...225..655G
Altcode:
  The solar La and Lfl lines of hydrogen have been measured at the center
  of the disk with the LPSP spectrometer aboard OSO 8. These line profiles
  are compared with theoretical profiles obtained with different solar
  atmospheric models, assuming either complete or partial frequency
  redistribution in scattering. The assumption of microturbulence for
  the velocity fields appears insufficient to account for the profiles
  of the line cores; better results are obtained with a blend of micro-
  and macroturbulence, which shows the need of a generalized treatment of
  the turbulent motions in the formation of these lines. If the effects
  of partial redistribution are taken into account, a good fit of the
  line wings requires higher temperatures, in the region under the
  plateau, than in the reference atmospheric model of Vernazza, Avrett,
  and Loeser. Subject headings: line formation - line profiles - Sun:
  chromosphere - Sun: spectra - ultraviolet: spectra

Title: Simultaneous time-resolved observations of the H Lalpha ,
    Mg k 2795 Å, and Ca K solar lines.
Authors: Artzner, G.; Leibacher, J.; Vial, J. C.; Lemaire, P.;
   Gouttebroze, P.
Bibcode: 1978ApJ...224L..83A
Altcode:
  No abstract at ADS

Title: Calibrated full disk solar H I Lyman-alpha and Lyman-beta
    profiles.
Authors: Lemaire, P.; Charra, J.; Jouchoux, A.; Vidal-Madjar, A.;
   Artzner, G. E.; Vial, J. C.; Bonnet, R. M.; Skumanich, A.
Bibcode: 1978ApJ...223L..55L
Altcode:
  Resolved solar H I Ly-alpha and -beta profiles have been recorded by the
  French LPSP experiment on OSO 8. Intensity observations at the center
  and the limb have been combined to obtain flux-equivalent profiles
  (5.46 plus or minus 30 percent and 0.078 plus or minus 25 percent
  erg/sq cm per sec for Ly-alpha and -beta, respectively). Comparison of
  the flux profiles with unresolved calibration rocket profiles allows
  one to obtain an absolute calibration.

Title: The LPSP instrument on OSO 8. II. In-flight performance and
    preliminary results.
Authors: Bonnet, R. M.; Lemaire, P.; Vial, J. C.; Artzner, G.;
   Gouttebroze, P.; Jouchoux, A.; Leibacher, J. W.; Skumanich, A.;
   Vidal-Madjar, A.
Bibcode: 1978ApJ...221.1032B
Altcode:
  The paper describes the in-flight performance for the first 18 months of
  operation of the LPSP (Laboratoire de Physique Stellaire et Planetaire)
  instrument incorporated in the OSO 8 launched June 1975. By means of
  the instrument, an absolute pointing accuracy of nearly one second
  was achieved in orbit during real-time operations. The instrument
  uses a Cassegrain telescope and a spectrometer simultaneously
  observing six wavelengths. In-flight performance is discussed with
  attention to angular resolution, spectral resolution, dispersion
  and grating mechanism (spectral scanner) stability, scattered light
  background and dark current, photometric standardization, and absolute
  calibration. Real-time operation and problems are considered with
  reference to pointing system problems, target acquisition, and L-alpha
  modulation. Preliminary results involving the observational program,
  quiet sun and chromospheric studies, quiet chromospheric oscillation
  and transients, sunspots and active regions, prominences, and aeronomy
  investigations are reported.

Title: Doppler Shifts measured in 0 VI line from OSO-B observations
    above and in the vicinity of plage Mc Math 13738.
Authors: Lemaire, P.; Skumanich, A.; Artzner, G.; Gouttebroze, P.;
   Vial, J. C.; Bonnet, R. M.; McWhirter, P.
Bibcode: 1978BAAS...10Q.440L
Altcode:
  No abstract at ADS

Title: OSO-8 Radio and X-ray observations of the 19 April 1977 flare.
Authors: Skumanich, A.; Jouchoux, A.; Castelli, J.; Lemaire, P.;
   Artzner, G.; Gouttebroze, P.; Vial, J. C.; Bonnet, R. M.
Bibcode: 1978BAAS...10..441S
Altcode:
  No abstract at ADS

Title: EUV observations of class-C X-ray flare by the LPSP
    (Laboratoire de Physique Stellaire et Planétaire du Centre National
    de la Recherche Scientifique) spectrometer on OSO-8.
Authors: Jouchoux, A.; Skumanich, A.; Bonnet, R. M.; Lemaire, P.;
   Artzner, G.; Leibacher, J.; Vial, J. C.; Vidal-Madjar, A.
Bibcode: 1977BAAS....9..432J
Altcode:
  No abstract at ADS

Title: The LPSP experiment on OSO-8. I - Instrumentation, description
    of operations, laboratory calibrations and pre-launch performances
Authors: Artzner, G.; Bonnet, R. M.; Vial, J. C.; Jouchoux, A.;
   Leibacher, J.; Vidal-Madjar, A.; Lemaire, P.
Bibcode: 1977SSI.....3..131A
Altcode:
  The characteristics of OSO-8, including its solar-pointed instrument
  assembly and rasters, are discussed, as well as the accompanying
  Laboratoire de Physique Stellaire et Planetaire (LPSP) instrumentation,
  which is designed to study the solar atmosphere with high spatial,
  spectral, and temporal resolution. The LPSP instrument, which consists
  of two subassemblies, a Cassegrainian telescope and a spectrometer,
  is described; main optical characteristics, including spectral lines
  observed, and means of correcting aberrations and eliminating stray
  light, are given for the spectrometer. Detectors and their capacities,
  and various filter wheel configurations available for detection of
  polarized light and discrimination of low orders of diffraction, are
  also described. The observation program, which consists of a study of
  solar prominences, flares, and dynamic and three-dimensional physical
  structures of the chromosphere, as well as determination of seasonal
  variations of some gases in earth's atmosphere, is reviewed. A detailed
  account of pre-launch tests and calibration procedures is also given.

Title: Extreme-Ultraviolet Observations of New Cycle Sunspots with
    the LPSP Spectrometer from OSO-8
Authors: Skumanich, A.; Jouchoux, A.; Artzner, G.; Bonnet, R. M.;
   Leibacher, J.; Lemaire, P.; Vial, J. C.; Vidal-Madjar, A.
Bibcode: 1977BAAS....9..340S
Altcode:
  No abstract at ADS

Title: On VI Profiles of Solar Quiet and Active Areas Recorded by
    OSO-8 LPSP Experiment".
Authors: Lemaire, P.; Artzner, G.; Vial, J. C.; Bonnet, R. M.;
   Gottebroze, P.; Jouchoux, A.; Vidal-Madjar, A.; McWhirter, P.;
   Leibacher, J.; Skumainich, A.
Bibcode: 1977uxsa.coll...46L
Altcode: 1977IAUCo..43...46L
  No abstract at ADS

Title: OSO-8 Observations of the EUV Chromospheric Network
Authors: Artzner, G.; Bonnet, R. M.; Leibacher, J.; Lemaire, P.;
   Skumanich, A.; Vial, J. C.; Vidal-Madjar, A.
Bibcode: 1976BAAS....8..332A
Altcode:
  No abstract at ADS

Title: Evolution of sunspot and active region morphology as observed
    on the resonance lines of Ca<SUP>+</SUP> (K, H), Mg<SUP>+</SUP>
    (k, h), hydrogen (Lalpha , Lbeta ), and O VI from OSO-8 (LPSP).
Authors: Artzner, G.; Skumanich, A.; Bonnet, R. M.; Vidal-Madjar,
   A.; Leibacher, J.; Lemaire, P.; Vial, J. C.
Bibcode: 1976BAAS....8..397A
Altcode:
  No abstract at ADS

Title: Periodic temporal phenomena in the solar chromosphere as
    observed from OSO-8 (LPSP).
Authors: Vial, J. C.; Leibacher, J.; Lemaire, P.; Artzner, G.; Bonnet,
   R. M.; Skumanich, A.; Vidal-Madjar, A.
Bibcode: 1976BAAS....8..397V
Altcode:
  No abstract at ADS

Title: Spatial variations of solar profiles of Ca<SUP>+</SUP> H and
    K, Mg<SUP>+</SUP> h and k, and Lyman alpha and beta (H I) resonance
    lines as observed from OSO-8 (LPSP).
Authors: Bonnet, R. M.; Artzner, G.; Leibacher, J.; Lemaire, P.;
   Skumanich, A.; Vial, J. C.; Vidal-Madjar, A.
Bibcode: 1976BAAS....8..397B
Altcode:
  No abstract at ADS

Title: Prominence Observations with the OSO-8 French Experiment
Authors: Vial, J. C.; Artzner, G.; Bonnet, R. M.; Lemaire, P.;
   Leibacher, J.; Skumanich, A.; Vidalmadjar, A.
Bibcode: 1976BAAS....8..344V
Altcode:
  No abstract at ADS

Title: High-Resolution Atmospheric Extinction Measurements from the
    French Experiment on Board the NASA Spacecraft OSO-8
Authors: Vidal-Madjar, A.; Roble, R. G.; Mankin, W. G.; Artzner, G.;
   Bonnet, R. M.; Lemaire, P.; Vial, J. C.
Bibcode: 1976ASSL...61..117V
Altcode: 1976aps..conf..117V
  No abstract at ADS

Title: High resolution atmospheric extinction measurements from the
    French experiment on board the NASA spacecraft OSO-8
Authors: Vidal-Madjar, A.; Artzner, G.; Bonnet, R. M.; Lemaire, P.;
   Vial, J. C.; Roble, R. G.; Mankin, W. G.
Bibcode: 1976atps.proc..117V
Altcode:
  The French instrument aboard OSO-8 is a multichannel, high-resolution UV
  spectrometer for observing very small areas of the sun simultaneously
  in the Ca II, Mg II, Lyman alpha, and Lyman beta lines. By observing
  extinction through the earth atmosphere, the spectrometer studies the
  three-dimensional structure and the composition of the atmosphere. The
  quality of data appears to give a 500 m vertical resolution both for
  O3 and O2; O3 is observed primarily from 55 to 75 km, while O2 is
  observed from 85 to 200 km. Data on the hydrogen absorption present a
  new method for evaluating exospheric temperature and atomic hydrogen
  density at each point of the exobase.

Title: Angular Dependence of the Optical Properties of a Narrow Band
    Interference Filter
Authors: Koutoumy, S.; Vial, J. -C.
Bibcode: 1973A&A....25..145K
Altcode:
  Summary. An interferential filter, 2" diameter, centered around Hoc
  line, has been studied. Its resolving power with unpolarized light,
  is 0/ 4. 1O . The instrumental width of the spectrometer was less than
  0.3 A and the field less than 10'. Wavelength shift A and half height
  bandwidth variation of the I.F. are given for different incident angles
  0. The beam was almost plane parallel; natural and linear polarized
  light were used. The wavelength splitting was not observed up to A
  10(a ). Polarization effects due to the filter are important and we
  empirically deduced the following formula: II- 1 (0.0610.01)00(A) for
  0 less than 5 . Key words: Hoc interference filter - polarization -
  spectral transmission - instrumental technique

Title: Intensity Distribution in the LYMAN-α Line at the Solar Limb
Authors: Vial, J. C.
Bibcode: 1970IAUS...36..260V
Altcode:
  No abstract at ADS

