Author name code: lemaire ADS astronomy entries on 2022-09-14 author:"Lemaire, Philippe" ------------------------------------------------------------------------ Title: State-of-the-art of photorefractive holographic interferometry and potentialities for space applications Authors: Georges, Marc; Lemaire, Philippe; Pauliat, Gilles; Launay, Jean-Claude; Roosen, Gérald Bibcode: 2018SPIE10570E..1GG Altcode: This paper, "State-of-the-art of photorefractive holographic interferometry and potentialities for space applications," was presented as part of International Conference on Space Optics—ICSO 1997, held in Toulouse, France. 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: Prospects for the design of an ultraviolet imaging Fourier transform spectrometer Authors: Lemaire, Philippe Bibcode: 2017SPIE10569E..13L Altcode: Recent results from solar observations in the far and extremeultraviolet (FUV/EUV) obtained from SOHO (SOlar and Heliospheric Observatory) and TRACE (Transition Region Camera) show the extreme variability of the solar atmosphere. Within the limited resolution of the instruments (1-2 arcseconds) horizontal and vertical velocities up-to 100 to 400 km s-1 have been measured. With an horizontal velocity of 100 km s-1 an one arsecond structure crosses the one arcsecond slit width of a classical slit spectrometer in less than 10 seconds. In the future, with higher angular resolution (e.g. 0.1 arcsecond), the capability to study small structures will be greatly reduced by a classical slit spectrometer. To be able to characterize the small scale solar atmospheric structures formed in the 104 K to 106 K temperature range (which emit in the 30 to 180 nm wavelength range) a spectrometer without slit (or with wide slit) is required. At the same time to obtain an accurate measurement of the doppler velocity an high spectral resolution is needed. The two requirements, high spectral resolution and large slit, are difficult to be simultaneously fulfilled with a classical slit spectrometer within the limited volume of a space instrumentation. Also, we propose to use an Imaging Fourier Transform Spectrometer (IFTS) to provide simultaneously a bidimensionnal field and an accurate determination of line profiles and positions. The development of Fourier Transform Spectrometers (FTS), although popular in the infrared, has been very limited in the UV/FUV by the lack of very high quality beam splitter. Since 10 years, the use of diffraction gratings as beam splitters has been suggested and few intruments have been built ([Chak 94]; [Clea 92]; [File 00]). These instruments illustrate some applications in the new wavelength domain opened by using a beam splitter grating, but do not yet provide the full capabilities of an FTS. In this paper we present several optical schemes which can provide the full capabilities of a complete IFTS in the FUV/EUV spectral range. Title: Development of optical ground verification method for μm to sub-mm reflectors Authors: Stockman, Y.; Thizy, C.; Lemaire, P.; Georges, M.; Mazy, E.; Mazzoli, A.; Houbrechts, Y.; Rochus, P.; Roose, S.; Doyle, D.; Ulbrich, G. Bibcode: 2017SPIE10568E..1KS Altcode: Large reflectors and antennas for the IR to mm wavelength range are being planned for many Earth observation and astronomical space missions and for commercial communication satellites as well. Scientific observatories require large telescopes with precisely shaped reflectors for collecting the electro-magnetic radiation from faint sources. The challenging tasks of on-ground testing are to achieve the required accuracy in the measurement of the reflector shapes and antenna structures and to verify their performance under simulated space conditions (vacuum, low temperatures). Due to the specific surface characteristics of reflectors operating in these spectral regions, standard optical metrology methods employed in the visible spectrum do not provide useful measurement results. The current state-of-the-art commercial metrology systems are not able to measure these types of reflectors because they have to face the measurement of shape and waviness over relatively large areas with a large deformation dynamic range and encompassing a wide range of spatial frequencies. 3-D metrology (tactile coordinate measurement) machines are generally used during the manufacturing process. Unfortunately, these instruments cannot be used in the operational environmental conditions of the reflector. The application of standard visible wavelength interferometric methods is very limited or impossible due to the large relative surface roughnesses involved. A small number of infrared interferometers have been commercially developed over the last 10 years but their applications have also been limited due to poor dynamic range and the restricted spatial resolution of their detectors. These restrictions affect also the surface error slopes that can be captured and makes their application to surfaces manufactured using CRFP honeycomb technologies rather difficult or impossible. It has therefore been considered essential, from the viewpoint of supporting future ESA exploration missions, to develop and realise suitable verification tools based on infrared interferometry and other optical techniques for testing large reflector structures, telescope configurations and their performances under simulated space conditions. Two methods and techniques are developed at CSL. The first one is an IR-phase shifting interferometer with high spatial resolution. This interferometer shall be used specifically for the verification of high precision IR, FIR and sub-mm reflector surfaces and telescopes under both ambient and thermal vacuum conditions. The second one presented hereafter is a holographic method for relative shape measurement. The holographic solution proposed makes use of a home built vacuum compatible holographic camera that allows displacement measurements from typically 20 nanometres to 25 microns in one shot. An iterative process allows the measurement of a total of up to several mm of deformation. Uniquely the system is designed to measure both specular and diffuse surfaces. 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: 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.
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.
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.
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.
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.

Profiles are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/581/A26 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.

(2 data files). Title: The SUMER Data in the SOHO Archive Authors: Curdt, W.; Germerott, D.; Wilhelm, K.; Schühle, U.; Teriaca, L.; Innes, D.; Bocchialini, K.; Lemaire, P. Bibcode: 2014SoPh..289.2345C Altcode: 2013arXiv1309.1314C We have released an archive of all observational data of the VUV spectrometer Solar Ultraviolet Measurements of Emitted Radiation (SUMER) on SOHO that have been acquired until now. The operational phase started with `first light' observations on 27 January 1996 and will end in 2014. Future data will be added to the archive when they become available. The archive consists of a set of raw data (Level 0) and a set of data that are processed and calibrated to the best knowledge we have today (Level 1). This communication describes step by step the data acquisition and processing that has been applied in an automated manner to build the archive. It summarizes the expertise and insights into the scientific use of SUMER spectra that has accumulated over the years. It also indicates possibilities for further enhancement of the data quality. With this article we intend to convey our own understanding of the instrument performance to the scientific community and to introduce the new, standard FITS-format database. 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:
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.
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).
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: 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: Space telescopes Authors: Lemaire, Philippe; Aschenbach, Bernd; Seely, John F. Bibcode: 2010ISSIR...9..165L Altcode: A brief survey of normal and grazing incidence space telescope types is given. The optimization of telescope efficiency either by dedicated single, bi-layer or multilayer coatings is described. An outlook of solar and stellar coronagraphs is included. Title: Normal- and grazing-incidence gratings and mountings used in space Authors: Lemaire, Philippe Bibcode: 2010ISSIR...9..193L Altcode: In most spectrometers, the grating is the component chosen to give the necessary spectral resolution either to filter the wavelength band or to obtain the line profiles. An overview of the grating properties and mountings used in space instrumentation is given. Title: The Ly-α profile and center-to-limb variation of the quiet Sun Authors: Curdt, W.; Tian, H.; Teriaca, L.; Schühle, U.; Lemaire, P. Bibcode: 2008A&A...492L...9C Altcode: 2008arXiv0812.1441C Aims: We study the emission of the hydrogen Lyman-α line in the quiet Sun, its center-to-limb variation, and its radiance distribution. We also compare quasi-simultaneous Ly-α and Ly-β line profiles.
Methods: We used the high spectral and spatial resolution of the SUMER spectrometer and completed raster scans at various locations along the disk. For the first time, we used a method to reduce the incoming photon flux to a 20%-level by partly closing the aperture door. We also performed a quasi-simultaneous observation of both Ly-α and Ly-β at the Sun center in sit-and-stare mode. We infer the flow characteristic in the Ly-α map from variations in the calibrated λ 1206 Si iii line centroids.
Results: We present the average profile of Ly-α, its radiance distribution, its center-to-limb behaviour, and the signature of flows on the line profiles. Little center-to-limb variation and no limb brightening are observed in the profiles of the Ly-α line. In contrast to all other lines of the Lyman series, which have a red-horn asymmetry, Ly-α has a robust and - except for dark locations - dominating blue-horn asymmetry. There appears to be a brightness-to-asymmetry relationship. A similar and even clearer trend is observed in the downflow-to-asymmetry relationship. This important result is consistent with predictions from models that include flows. However, the absence of a clear center-to-limb variation in the profiles may be more indicative of an isotropic field than a mainly radial flow.
Conclusions: It appears that the ubiquitous hydrogen behaves in a similar way to a filter that dampens all signatures of the line formation by processes in both the chromosphere and transition region. Title: The line profile and center-to-limb variation of quiet-Sun Lyman-alpha emission Authors: Curdt, W.; Tian, H.; Teriaca, L.; Schühle, U.; Lemaire, P. Bibcode: 2008ESPM...12.2.91C Altcode: We study the emission of the hydrogen Lyman-alpha line in the quiet Sun, its center-to-limb variation, and its radiance distribution, which we also compare to the Lyman-beta line. We use the high spectral and spatial resolution of the SUMER spectrometer and take raster scans at various locations on the disk. For the first time, we have used a new method to reduce the incoming photon flux to a 20%-level by partly closing the aperture door. We also performed a quasi-simultaneous observation of both Ly-a and Ly-b at Sun centre in sit-and-stare mode. We deduce the flow characteristic in Ly-a map from variations of the calibrated Si III line centroids. We present the average profile of Ly-a, its radiance distribution, its center-to-limb behaviour, and the signature of flows on the line profiles. Different from all other lines of the Lyman series, which have a red-horn asymmetry, Ly-a has a robust and dominating blue-horn asymmetry. To our knowledge, this result is only predicted by models which include flows. Title: Rewritable VPHGs based on photochromic materials Authors: Bianco, Andrea; Toso, Giorgio; Dassa, Giovanni; Chiara, Bertarelli; Molinari, Emilio; Zerbi, Filippo M.; Zerbi, Giuseppe; Georges, Marc; Lemaire, Philippe Bibcode: 2008SPIE.7018E..2MB Altcode: 2008SPIE.7018E..85B Volume phase holographic gratings (VPHGs) are becoming an interesting alternative to the ruled gratings in modern astronomical instrumentation. Photochromic materials with thermal stability are good candidates for the development of holographic optical elements and in particular for VPHGs. VPHGs based on photochromic materials can be written and erased many times without the degradation of the material; moreover the material does not need any developing process after the exposure, making the writing process very simple. We have already studied photochromic materials for this aim in the framework of the JRA6 (Opticon Project, FP6) and we found that large modulations of the refractive index can be achieved using diarylethene polymers. Going from the materials characterization to technology, substrates with larger thickness and good optical properties are required. Herein we present the development of new technique to tailor the thickness of the photochromic films in two ranges: 5 - 30 micron and 700 - 1000 micron. The former are suitable for the development of broadband VPHGs, whereas the latter are suitable for narrow band tunable filters application. Details on the optical properties of the films are reported. Finally, a holographic set-up based on an Ar+ laser has been optimized in order to write the gratings. Title: Performances of NIR VPHGs at cryogenic temperatures Authors: Insausti, M.; Garzón, F.; Rasilla, J. L.; Blanche, P. -A.; Lemaire, P. Bibcode: 2008SPIE.7018E..4TI Altcode: 2008SPIE.7018E.154I We summarize the performances measured at room temperature and in cryogenic conditions of a set of NIR Volume Phase Holographic Gratings (VPHGs) which can then be used in astronomical instrumentations. VPHGs are novel optical components which can replace standard transmission gratings. Instead of a surface modulation a diffraction index modulation printed in a volume of material generates the diffraction according to the required specifications. Results on transmission and wavefront deformation are presented and compared in the two temperature regimes. These results were achieved along the run of the Joint Research Action 6 of OPTICON FP6 programme whose participating institutions are Osservatorio Astronomico di Brera (INAF), Instituto de Astrofísica de Canarias, Centre Spatial de Liege, Politecnico di Milano and European Southern Observatory. Title: WIYN bench upgrade: a revitalized spectrograph Authors: Bershady, M.; Barden, S.; Blanche, P. -A.; Blanco, D.; Corson, C.; Crawford, S.; Glaspey, J.; Habraken, S.; Jacoby, G.; Keyes, J.; Knezek, P.; Lemaire, P.; Liang, M.; McDougall, E.; Poczulp, G.; Sawyer, D.; Westfall, K.; Willmarth, D. Bibcode: 2008SPIE.7014E..0HB Altcode: 2008SPIE.7014E..15B We describe the redesign and upgrade of the versatile fiber-fed Bench Spectrograph on the WIYN 3.5m telescope. The spectrograph is fed by either the Hydra multi-object positioner or integral-field units (IFUs) at two other ports, and can be configured with an adjustable camera-collimator angle to use low-order and echelle gratings. The upgrade, including a new collimator, charge-coupled device (CCD) and modern controller, and volume-phase holographic gratings (VPHG), has high performance-to-cost ratio by combining new technology with a system reconfiguration that optimizes throughput while utilizing as much of the existing instrument as possible. A faster, all-refractive collimator enhances throughput by 60%, nearly eliminates the slit-function due to vignetting, and improves image quality to maintain instrumental resolution. Two VPH gratings deliver twice the diffraction efficiency of existing surface-relief gratings: A 740 l/mm grating (float-glass and post-polished) used in 1st and 2nd-order, and a large 3300 l/mm grating (spectral resolution comparable to the R2 echelle). The combination of collimator, high-quantum efficiency (QE) CCD, and VPH gratings yields throughput gain-factors of up to 3.5. 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 correlation between coronal Doppler shifts and the supergranular network Authors: Aiouaz, T.; Peter, H.; Lemaire, P. Bibcode: 2007A&A...466..689A Altcode: No abstract at ADS 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 τ500=1. Oscillations in lines originating at similar altitudes exhibit different behaviors which we discuss in terms of the formation of the lines. Title: Quiet sun XUV and EUV spectroscopy Authors: Lemaire, P. Bibcode: 2007AdSpR..39.1876L Altcode: The two XUV-EUV spectrometers on SOHO have collected a large amount of data in the 6000-10 6 K solar plasma temperature range. These data have allowed us to greatly enhance our knowledge of the processes acting in the solar atmosphere, from the chromosphere to the corona. Some results on the quiet Sun structure (network, quiet Sun versus coronal hole), on the dynamics (velocities, waves, transient events), and the main characteristics of the quiet Sun atmosphere are presented and discussed. 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: 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: 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: 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&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: Dynamic holography for the space qualification of large reflectors Authors: Thizy, C.; Stockman, Y.; Doyle, D.; Lemaire, P.; Houbrechts, Y.; Georges, M.; Mazzoli, A.; Mazy, E.; Tychon, I.; Ulbrich, G. Bibcode: 2005SPIE.5965..269T Altcode: The next generation of infrared - sub mm space telescopes requires reflectors with large dimensions, high quality and, according to weight issues, are based on composite or new materials technology. The challenging tasks of on-ground testing are to achieve the required accuracy in the measurement of these reflectors shape and antenna structures and to verify their performance under simulated space conditions (vacuum, low-high temperatures). A holographic camera for the verification and validation of this type of reflector in a space environment is presented. A diffuser is implemented to measure the deformations of reflective surfaces in a more flexible way. The system has been made compatible with the vacuum conditions. Some elements of the holographic camera (camera lenses, CCD, crystal, optical fibre) have been adapted and tested under vacuum. The metrological certification of the whole system is realised by the measurement of a parabolic CFRP reflector with a 1.1 meter diameter. The results are compared to the one achieved with a high spatial resolution IR interferometer on the same reflector in laboratory conditions and under thermal vacuum conditions. This later test consists in measuring the deformations of the reflector between an initial state at a selected temperature and a final state at another temperature. The comparison between the high spatial resolution IR interferometer and this dynamic holographic method showed very good qualitative and quantitative agreement between the techniques, thus verifying the potential of this new Holographic approach. Title: On the nature of the unidentified solar emission near 117 nm Authors: Wilhelm, K.; Schühle, U.; Curdt, W.; Hilchenbach, M.; Marsch, E.; Lemaire, P.; Bertaux, J. -L.; Jordan, S. D.; Feldman, U. Bibcode: 2005A&A...439..701W Altcode: Spectral observations of the Sun in the vacuum-ultraviolet wavelength range by SUMER on SOHO led to the discovery of unusual emission features - called humps here - at 116.70 nm and 117.05 nm on either side of the He i 58.43 nm line. This resonance line is seen in the second order of diffraction, whereas the humps are recorded in the first order with the SUMER spectrometer. In its spectra both orders are superimposed. Two less pronounced humps can be detected at 117.27 nm and near 117.85 nm. After rejecting various possibilities of an instrumental cause of the humps, they are studied in different solar regions. Most of the measurements, in particular those related to the limb-brightening characteristics, indicate that the humps are not part of the background continuum. An assembly of spectrally-unresolved atomic or ionic emission lines might be contributing to the hump at 117.05 nm, but no such lines are known near 116.7 nm. It is concluded that we detect genuine radiation, the generation of which is not understood. A two-photon emission process, parametric frequency down conversion, and molecular emissions are briefly considered as causes of the humps, but a final conclusion could not be reached. Title: The correlation between coronal Doppler shifts and the supergranular network Authors: Aiouaz, T.; Peter, H.; Lemaire, P. Bibcode: 2005A&A...435..713A Altcode: We examine properties of line profiles as found with large raster scans of the solar corona acquired by the UV spectrometer SUMER on board SOHO. The observed regions include an equatorial coronal hole, a polar coronal hole, as well as surrounding quiet Sun areas. In order to reveal the network and remove strong local brightenings, a filter is applied to a continuum image. The filtered continuum image, the intensity image and the dopplergram are used to produce “scatter diagrams” (dispersion plots). We find correlations between the chromospheric network, the Ne VIII (770 Å) intensity and the Ne VIII (770 Å) Doppler shift in quiet Sun areas and in coronal holes. We establish that the maximum outflow (blue-shift) at low corona temperatures does not appear in the centre of the network but rather near network boundaries. Furthermore the maximum blue-shift seems to appear in the dark regions in Ne VIII line intensity, which is in agreement with Wilhelm (2000). The opposite correlation appears for very low intensities (less than half of the average intensity), revealing in these regions a lack of energy to either accelerate the solar wind or produce any detectable radiation. The absence of magnetic field concentration in these regions in a reconstructed magnetogram from a MDI/SOHO series seems to confirm the lack of energy. 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: On the Outflow at Solar Corona Heights Authors: Aiouaz, T.; Peter, H.; Lemaire, P. Bibcode: 2004ESASP.575..331A Altcode: 2004soho...15..331A No abstract at ADS 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: Mosaiced and high line frequency VPH gratings for astronomy Authors: Blanche, Pierre-Alexandre; Gailly, Patrick; Habraken, Serge; Lemaire, Philippe; Jamar, Claude Bibcode: 2004SPIE.5494..208B Altcode: To increase the size of the volume phase holographic gratings the Centre Spatial de Liege can produce, mosaic technic has been tested and characterized. This method consists of assembling VPH gratings recorded and processed independently into one larger grating. By this way, the final grating size becomes virtually unlimited and dispersive elements can accommodate the largest telescope beams. The second research line about VPH gratings was the high line frequency domain: ν > 3000 lp/mm. Actually, for these frequencies, diffraction according to TE and TM modes is maximum for different wavelengths. However, it is possible to tune the index modulation to three times what is usually required to use the first diffraction TE peak. In this case, the second TE maximum matches the first TM maximum and unpolarized light is so entirely diffracted. This article also summarizes our prospects in the field of very high index modulation gratings where Δn as high as 0.14 has been reached; cryogenic temperature operation for which we have demonstrated our VPH gratings stand -180°C without any Blaze modification; and wavefront correction by post-polishing to minimize diffracted beam aberrations. With this latter technique, λ/6 wavefront over 10 cm diameter has been obtained in the first trial. Title: Development of optical ground verification method for μm to sub-mm reflectors Authors: Stockman, Y.; Thizy, C.; Lemaire, P.; Georges, M.; Mazy, E.; Mazzoli, A.; Houbrechts, Y.; Rochus, P.; Roose, S.; Doyle, D.; Ulbrich, G. Bibcode: 2004ESASP.554..721S Altcode: 2004icso.conf..721S Large reflectors and antennas for the IR to mm wavelength range are being planned for many Earth observation and astronomical space missions and for commercial communication satellites as well. Scientific observatories require large telescopes with precisely shaped reflectors for collecting the electro-magnetic radiation from faint sources. The challenging tasks of on-ground testing are to achieve the required accuracy in the measurement of the reflector shapes and antenna structures and to verify their performance under simulated space conditions (vacuum, low temperatures). Due to the specific surface characteristics of reflectors operating in these spectral regions, standard optical metrology methods employed in the visible spectrum do not provide useful measurement results. The current state-of-the-art commercial metrology systems are not able to measure these types of reflectors because they have to face the measurement of shape and waviness over relatively large areas with a large deformation dynamic range and encompassing a wide range of spatial frequencies. 3-D metrology (tactile coordinate measurement) machines are generally used during the manufacturing process. Unfortunately, these instruments cannot be used in the operational environmental conditions of the reflector. The application of standard visible wavelength interferometric methods is very limited or impossible due to the large relative surface roughnesses involved. A small number of infrared interferometers have been commercially developed over the last 10 years but their applications have also been limited due to poor dynamic range and the restricted spatial resolution of their detectors. These restrictions affect also the surface error slopes that can be captured and makes their application to surfaces manufactured using CRFP honeycomb technologies rather difficult or impossible. It has therefore been considered essential, from the viewpoint of supporting future ESA exploration missions, to develop and realise suitable verification tools based on infrared interferometry and other optical techniques for testing large reflector structures, telescope configurations and their performances under simulated space conditions. The first one is an IR-phase shifting interferometer with high spatial resolution. This interferometer shall be used specifically for the verification of high precision IR, FIR and sub-mm reflector surfaces and telescopes under both ambient and thermal vacuum conditions. The second one presented hereafter is a holographic method for relative shape measurement. The holographic solution proposed makes use of a home built vacuum compatible holographic camera that allows displacement measurements from typically 20 nanometres to 25 microns in one shot. An iterative process allows the measurement of a total of up to several mm of deformation. Uniquely the system is designed to measure both specular and diffuse surfaces. 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.

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.

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: Development of imaging arrays for solar UV observations based on wide band gap materials Authors: Schuehle, Udo H.; Hochedez, Jean-Francois E.; Pau, Jose Luis; Rivera, Carlos; Munoz, Elias; Alvarez, Jose; Kleider, Jean-Paul; Lemaire, Philippe; Appourchaux, Thierry; Fleck, Bernhard; Peacock, Anthony; Richter, Mathias; Kroth, Udo; Gottwald, Alexander; Castex, Marie-Claude; Deneuville, Alain; Muret, Pierre; Nesladek, Milos; Omnes, Franck; John, Joachim; Van Hoof, Chris Bibcode: 2004SPIE.5171..231S Altcode: Solar ultraviolet imaging instruments in space pose most demanding requirements on their detectors in terms of dynamic range, low noise, high speed, and high resolution. Yet UV detectors used on missions presently in space have major drawbacks limiting their performance and stability. In view of future solar space missions we have started the development of new imaging array devices based on wide band gap materials (WBGM), for which the expected benefits of the new sensors - primarily visible blindness and radiation hardness - will be highly valuable. Within this initiative, called "Blind to Optical Light Detectors (BOLD)", we have investigated devices made of AlGa-nitrides and diamond. We present results of the responsivity measurements extending from the visible down to extreme UV wavelengths. We discuss the possible benefits of these new devices and point out ways to build new imaging arrays for future space missions. Title: Outflow Velocities in Polar Coronal Holes Authors: Gabriel, A. H.; Bely-Dubau, F.; Lemaire, P.; Antonucci, E. Bibcode: 2004IAUS..219..635G Altcode: 2003IAUS..219E.100G It is well established that the fast solar wind originates during the solar minimum from the polar coronal holes. The object is to investigate this wind onset region to identify the solar structures responsible. We report here the first measurements of outflow velocities between 1.0 and 1.3 Ro in solar plumes using XUV spectral lines from SUMER/SOHO and the Doppler dimming technique. In contrast to what has been suggested by several other observers using SOHO data we conclude that the wind velocity in plumes is greater than in the interplume regions. This tendency diminishes with height so that it may vanish or even reverse at greater distances. We show that one half of the solar wind observed at 1 A.U. from Ulysses originates from the solar plumes at 1.1 Ro. We are extending these observations to 4 Ro using the UVCS/SOHO spectro-coronagraph to understand the connection with plumes seen at greater distances. Initial indications suggest a change in the physical nature of plumes around 2.0 Ro raising questions concerning their relation to the frequently seen white-light plumes at large distances. We explore the possible connection between polar plumes the supergranule network and coronal heating in non-hole regions. Title: A Search for Signatures of Preferential Heating by Ion Cyclotron Waves in the Low Corona Authors: Dolla, L.; Solomon, J.; Lemaire, P. Bibcode: 2004ESASP.547..391D Altcode: 2004soho...13..391D Pointing above the solar Poles (above the limb), in May 2002 (MEDOC Campaign #9), with the SUMER spectrometer (on board SOHO), we measure the width of several minor ion lines. Assuming the same so-called "unresolved velocity" for each ion, we derive the temperature of the ion species. We then investigate the possible presence of preferential heating of ions presenting a low charge-to-mass ratio, characteristic of ion cyclotron interaction. For a given altitude, the trend of the temperature as a function of the charge-to-mass ratio is difficult to interpret, due to the unknown value of . We get rid of that constraint by analysing the difference of line width with the altitude. Interpreted in terms of difference in temperature only, it is independent of the absolute value of the temperature, or of the unresolved velocity. Nevertheless, one could interpret, to a certain extent, the difference in line width as an increase of the unresolved velocity with altitude. We conclude that our results support the possibility of a preferential ion cyclotron heating. Title: Quiet sun xuv and euv spectroscopy Authors: Lemaire, P. Bibcode: 2004cosp...35.4447L Altcode: 2004cosp.meet.4447L The two XUV - EUV spectrometers on SOHO have collected a large amount of data in the 6000 K - 1.E6 K solar plasma temperature range. These data have allowed to greatly enhance our knowledge of the processes acting in the solar atmosphere, from the chromosphere to the corona. Some results on the quiet Sun structure (network, quiet Sun versus coronal hole), on the dynamics (velocities, waves, transient events), and the main characteristics of the quiet Sun atmosphere are presented and discussed. 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: Dynamics and Properties of Coronal Funnels Authors: Aiouaz, T.; Peter, H.; Lemaire, P.; Keppens, R. Bibcode: 2004ESASP.547..375A Altcode: 2004soho...13..375A Coronal funnels are open magnetic structures connecting the chromosphere with the solar corona [5, 3]. We investigate the stationary plasma flow out of funnels with a 2D- MHD model. The funnel area function is derived from a magnetic field model and the funnel is approximately 10 Mm high and 20 Mm wide. The energy balance includes radiative losses, thermal conduction, and a parametrized heating function. We adjust the parameters to the quantities measured in the lower solar corona. We obtained 2D plasma properties (e.g. density, temperature, flow speed, etc.) within the funnel. From the results of the MHD calculation we synthesize emision profiles of various lines formed in the transition region from the chromosphere to the corona. This allows us to study e.g. the Doppler shifts at various temperatures across the funnel and thus enables a detailed comparison of the model results with observations. For this we investigate SUMER data and study Doppler shifts perpendicular to the chromospheric network for different emission lines, where a tessalation technique is used to derive the outlines of the chromospheric network. In this paper typical results are presented for the Ne VIII(770.4 Å) line. Preliminary results show that these model caclulations compare well to the observations. Title: Is there ion cyclotron preferential heating in the low solar corona ? Authors: Dolla, L.; Solomon, J.; Lemaire, P. Bibcode: 2004cosp...35.2315D Altcode: 2004cosp.meet.2315D The profile of optically thin lines in the solar corona is the reflection of the kinetic distribution of the emitting ion species, integrated over the solid angle of the observation. Then, the line width can be interpreted as the sum of two contributions : the thermal broadening of the kinetic distribution of each single elementary volume, and an additional non-thermal broadening due to the dispersion of fluid velocities of all the elementary volumes, at scales smaller than the spatial resolution of the instrument, and along the line of sight (fluid motion due to, e.g., Alfvén waves or turbulence). We report measurements of EUV coronal line widths, with SoHO/SUMER, between 1 and 1.2 solar radii above polar coronal holes. We investigate the presence of preferential heating of ions with the lowest charge-to-mass ratios, that could be induced by ion cyclotron waves. To distinguish between the thermal and non-thermal contributions to the line width, and correctly interpret its radial variation with altitude, one would need, in principle, both ions with low and with heavy masses for each charge-to-mass ratio (or at least the same mass for each charge-to-mass ratio). This is not the case with the ions emitting in the SUMER spectral range : low charge-to-mass ratios are highly correlated with heavy masses. Nevertheless, we note some trend towards ion cyclotron preferential heating, although the data are also compatible with a common increase of the non-thermal velocity for all ions. In this work, we pay careful attention to the problem of instrumental stray light, by correcting the observed line profiles by a predicted stray light profile, when a coronal line is blended with a ``cold'' line seen as stray light. 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: 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: Dynamics and Properties of Coronal Funnels Authors: Aiouaz, T.; Peter, H.; Lemaire, Philippe; Keppens, Rony Bibcode: 2003ANS...324....7A Altcode: 2003ANS...324..B01A No abstract at ADS Title: Images of the solar upper atmosphere from SUMER on SOHO Authors: Feldman, Uri; Dammasch, Ingolf E.; Wilhelm, Klaus; Lemaire, Philippe; Hassler, Donald M.; Battrick, Bruce Bibcode: 2003ESASP1274.....F Altcode: 2003isua.book.....F During the first year of SOHO operations and later in 1999, SUMER acquired several thousand images of the solar upper atmosphere. This atlas includes most of the full-Sun images that SUMER recorded and the majority of its images acquired during the Whole-Sun Month campaign. One of our main tasks while selecting the atlas format has been the implementation of our desire to maintain the high spatial resolution that SUMER achieved. In particular we hope that people with average vision will be able to see the finest details of the plasma structures that SUMER can resolve. Thus the page size has been chosen such that the finest resolution element in the images corresponds to approximately 250 μm in this atlas. The images in the atlas were recorded in spectral lines or in continuum radiation emitted by plasmas spanning the electron temperature domain from 1×104K to 1.4×106K. Some of the images were recorded simultaneously in radiation emitted by plasmas of different temperatures. Due to substantial differences of the plasma properties from which the radiation originated, the atlas provides a unique source for studying many aspects of the solar upper atmosphere. Title: The Contribution of Polar Plumes to the Fast Solar Wind Authors: Gabriel, A. H.; Bely-Dubau, F.; Lemaire, P. Bibcode: 2003ApJ...589..623G Altcode: The Doppler dimming technique is used for the first time to study ultraviolet polar plumes in the height range of 1.05-1.35 Rsolar, using observations from the spectrometer SUMER on the Solar and Heliospheric Observatory. It is found that, contrary to a number of published suggestions, outflow velocities in the plumes exceed those in the interplume regions. Plume velocities are in excess of 60 km s-1 and are approximately constant throughout this height region. They tend to converge with the velocity of the accelerating interplume material at some height above our region of study. The analysis suggests that plume material makes a substantial contribution to the total line of sight, favoring either a ``curtain'' model for plumes or a chance alignment of a number of elementary cylindrical plumes. The intrinsic local density of plume material is some 20%-50% in excess of the interplume regions. Estimation of the total mass outflow indicates that approximately half of the fast solar wind at 1.1 Rsolar arises from plumes, with the remainder from interplume material. This result validates the published electron temperature profile of David et al. for the fast wind onset, which had been questioned over the suggestion that the flow velocity might be negligible in solar plumes. 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 Ro 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: New UV detectors for solar observations Authors: Hochedez, Jean-Francois E.; Schuehle, Udo H.; Pau, Jose L.; Alvarez, Jose; Hainaut, Olivier; Appourchaux, Thierry P.; Auret, F. D.; Belsky, Andrei; Bergonzo, Philippe; Castex, M. C.; Deneuville, A.; Dhez, Pierre; Fleck, Bernhard; Haenen, Ken; Idir, Mourad; Kleider, Jean Paul; Lefeuvre, Elie; Lemaire, Philippe; Monroy, E.; Muret, P.; Munoz, Elias; Nesladek, Milos; Omnes, Franck; Pace, Emanuele; Peacock, Anthony J.; Van Hoof, Chris A. Bibcode: 2003SPIE.4853..419H Altcode: BOLD (Blind to the Optical Light Detectors) is an international initiative dedicated to the development of novel imaging detectors for UV solar observations. It relies on the properties of wide bandgap materials (in particular diamond and Al-Ga-nitrides). The investigation is proposed in view of the Solar Orbiter (S.O.) UV instruments, for which the expected benefits of the new sensors -primarily visible blindness and radiation hardness- will be highly valuable. Despite various advances in the technology of imaging detectors over the last decades, the present UV imagers based on silicon CCDs or microchannel plates exhibit limitations inherent to their actual material and technology. Yet, the utmost spatial resolution, fast temporal cadence, sensitivity, and photometric accuracy will be decisive for the forthcoming solar space missions. The advent of imagers based on wide-bandgap materials will permit new observations and, by simplifying their design, cheaper instruments. As for the Solar Orbiter, the aspiration for wide-bandgap material (WBGM) based UV detectors is still more sensible because the spacecraft will approach the Sun where the heat and the radiation fluxes are high. We describe the motivations, and present the program to achieve revolutionary flight cameras within the Solar Orbiter schedule as well as relevant UV measurements. Title: Large-scale DCG transmission holographic gratings for astronomy Authors: Blanche, Pierre-Alexandre; Habraken, Serge L.; Lemaire, Philippe C.; Jamar, Claude A. J. Bibcode: 2003SPIE.4842...31B Altcode: The recent interest of the astronomer community for volume phase holographic gratings is directly related to the enhancement of spectrograph throughput since this kind of grating can rise higher diffraction efficiency. Indeed, dichromated gelatine technology has demonstrated capability for 70-90% efficiency. From the heritage of several diffractive and holographic projects and applications, the Centre Spatial de Liege has recently decided to invest in the large-scale DCG grating technology. This paper will present the new facility which is now fully operational, its capability and first results obtained. Title: Linear polarization of the O VI lambda 1031.92 coronal line. II. Constraints on the magnetic field and the solar wind velocity field vectors in the coronal polar holes Authors: Raouafi, N. -E.; Sahal-Bréchot, S.; Lemaire, P. Bibcode: 2002A&A...396.1019R Altcode: Numerical computation results of the linear polarization parameters of the O VI lambda1031 .92 coronal line are presented. They are based on theoretical results obtained by Raouafi (2002 and 2000), which give the Stokes parameters of a resonance scattering spectral line sensitive simultaneously to the Hanle effect and to the Doppler redistribution. In the present coronal case, the Hanle effect is due to the coronal magnetic field and the Doppler redistribution to the macroscopic motion of the scattering O5+ coronal ions (solar wind velocity field vector). Constraints on the coronal magnetic field vector and on the solar wind velocity field vector are obtained by comparing the numerical results and the linear polarization measurements of the O VI lambda1031 .92 coronal line obtained through particular observations performed by SUMER/SoHO. 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: From chromosphere to corona through ground-based to space observatories Authors: Lemaire, P. Bibcode: 2002NCimC..25..719L Altcode: No abstract at ADS Title: Linear polarization of the O VI lambda 1031.92 coronal line. I. Constraints on the solar wind velocity field vector in the polar holes Authors: Raouafi, N. -E.; Sahal-Bréchot, S.; Lemaire, P.; Bommier, V. Bibcode: 2002A&A...390..691R Altcode: In the first part of the present work, we report on the determination of the linear polarization parameters of the O VI lambda1031 .92 coronal line (hereafter O VI D2). Spectropolarimetric observations done by the SUMER spectrometer on board the spacecraft SoHO during minimum activity of the solar cycle (March, 1996) in the south coronal hole were used to analyze the partial linear polarization of the D2 resonance line scattered by the O {VI} coronal ions. Widths of the O VI D2 and O VI 1037.61 (hereafter O VI D1) lines and limb-brightening determined from data observations of SUMER/SoHO are also presented. The second part of this work is devoted to the interpretation of the determined polarization parameters in terms of the macroscopic velocity field vector of the O VI coronal ions that can be assimilated to the solar wind velocity field. Numerical results of the linear polarization parameters of the O VI D2 coronal line are presented. Constraints on the strength and direction of the solar wind velocity vector are obtained by comparing the numerical and the observational results of the O VI D2 coronal line polarization parameters. In conclusion, the effect of the macroscopic velocity field vector of the scattering ions (Doppler redistribution) provides a first set of results compatible with the observations. However, the inclination of the derived set of compatible field vectors, with respect to the solar vertical, is higher than expected in a coronal hole. The result will be improved by the inclusion of the magnetic field effect (Hanle effect), which will be treated in a further paper. 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: Effect of the solar wind velocity field vector on the polarization of the O VI λ1032 coronal line Authors: Raouafi, N. -E.; Sahal-Bréchot, S.; Lemaire, P. Bibcode: 2002ESASP.508..471R Altcode: 2002soho...11..471R The linear polarization parameters of the O VI λ1032 coronal line (D2 line) are measured by using spectropolarimetric observations performed by the SUMER spectrometer on board the SoHO spacecraft during activity minimum of the solar cycle (March, 1996), in the south coronal hole. The interpretation of the determined polarization parameters in terms of the macroscopic velocity field vector of the O VI coronal ions (which can be assimilated to the solar wind velocity field) gives constraints on the strength and direction of the solar wind velocity field vector. They are obtained by comparing the numerical and the observational results of the linear polarization parameters of the O VI D2 coronal line. Title: Effect of the coronal magnetic field and the solar wind velocity field vectors on the polarization of the O VI λ1032 line Authors: Raouafi, N. -E.; Lemaire, P.; Sahal-Bréchot, S. Bibcode: 2002ESASP.508..403R Altcode: 2002soho...11..403R Numerical computation results of the combination of the Hanle effect (due to the coronal magnetic field) and to the Doppler redistribution effect (due to the solar wind velocity field) on the linear polarization parameters of the O VI λ1032 coronal line (D2 line) are presented. Constraints on the magnetic field and the solar wind velocity field vectors are obtained by comparing the present results and the measurements of the polarization parameters of the O VI D2 coronal line by using SUMER/SoHO polarimetric observations done in the south coronal polar hole during the minimum of the solar activity cycle. 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: SUMER in retrospective and future EUV spectrometers Authors: Lemaire, Philippe Bibcode: 2002ESASP.508..539L Altcode: 2002soho...11..539L The SUMER spectrometer normal incidence design comes from the improvement of previous designs and the development of new technologies. A review of some of the historical progresses is presented. An analysis of the needs for the solar transition and low coronal physics provides guidelines for future FUV-EUV spectrometers. To avoid the slit limitation we propose a 2D imaging Fourier transform spectrometer. 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: Solar Vacuum-ultraviolet Radiometry with SUMER Authors: Wilhelm, K.; Schuhle, U.; Curdt, W.; Dammasch, I. E.; Hollandt, J.; Lemaire, P.; Huber, M. C. E. Bibcode: 2002ISSIR...2..145W Altcode: 2002ESASR...2..145W; 2002rcs..conf..145W Since the beginning of 1996, the space-based telescope and spectrograph SUMER (Solar Ultraviolet Measurements of Emitted Radiation) on the SOlar and Heliospheric Observatory (SOHO) of ESA and NASA has obtained spectra of many features of the quiescent and active Sun with high spectral and spatial resolution. In addition, irradiance and radiance measurements of line and continuum emission have been performed in the wavelength range 46.5 nm to 161.0 nm. The instrument was radiometrically calibrated against the Berlin Electron Storage ring for SYnchrotron radiation (BESSY I), a primary source standard, with the help of a transfer source standard based on a hollow-cathode discharge lamp. A thorough cleanliness programme, specifically aimed at chemical contamination control, resulted in an excellent radiometric stability of the normal-incidence optical system as well as of the detectors. This has been verified under operational conditions by various techniques employed during the SOHO mission, such as line-ratio studies, observations of stars, and comparisons with other instruments. The observations provide vacuum-ultraviolet (VUV) radiometry of the Sun in many emission lines and continua of atoms and ions with relative standard uncertainties of 15 % (detector A) and 20 % (detector B) for the wavelength range 53 nm to 124 nm, with larger uncertainties outside this interval and after the SOHO recovery in 1998. We report on the present state of the SUMER radiometric calibration and provide a full bibliography related to this topic. Title: SUMER Stellar Observations to Monitor Responsivity Variations Authors: Lemaire, P. Bibcode: 2002ISSIR...2..265L Altcode: 2002ESASR...2..265L; 2002rcs..conf..265L Regular observations of α Leo have been performed by SUMER in order to track responsivity variations in the 95 nm to 160 nm range. Degradation in responsivity ranging from about 2 % to 5 % at 150 nm and 20 % at 100 nm have been demonstrated for the SUMER optical paths using both A and B detectors between 1996 and 1999. Later, between 1999 and 2001, with the optical path using the A detector, the 100 nm responsivity loss is about 20 %, while that at 150 nm is insignificant. Title: New UV Detector Concepts Authors: Hochedez, J. -F.; Schuhle, U.; Lemaire, P. Bibcode: 2002ISSIR...2..371H Altcode: 2002rcs..conf..371H; 2002ESASR...2..371H BOLD (Blind to the Optical Light Detectors) is an international initiative dedicated to the development of novel imaging detectors for UV solar observations. It relies on the properties of wide-bandgap semiconductor materials (in particular diamond and Al-Ganitrides). This investigation is proposed in view of the Solar Orbiter UV instruments, for which the expected benefits of the new sensors, visible blindness and radiation hardness, will be highly valuable. Despite various advances in the technology of imaging detectors over the last few decades, the present UV imagers based on silicon CCDs or microchannel plates exhibit limitations which are inherent to their actual material and technology. Yet the utmost spatial resolution, fast temporal cadence, sensitivity, and photometric accuracy will all be decisive for forthcoming solar space missions. The advent of imagers made of large wide-bandgap semiconductors would surmount many present weaknesses. This would open up new scientific prospects and, by simplifying their design, would even make the instruments cheaper. As for the Solar Orbiter, the aspiration for wide-bandgap semiconductor-based UV detectors is still more desirable because the spacecraft will approach the Sun where heat and radiation fluxes are high. We describe the motivations leading to such new developments, and present a programme to achieve revolutionary flight cameras within the Solar Orbiter schedule. Title: JOSO national report 2000-2001 - France Authors: Schmieder, B.; Mein, P.; Lemaire, P.; Pick, M.; Vilmer, N. Bibcode: 2002joso.book...56S Altcode: We report on the scientific advances in solar physics in France. The French Solar community is large split in different laboratories and observatories. We report on specific groups (THEMIS, SOHO, Nançay). Title: Volume Phase Holographic Gratings Made in Europe Authors: Habraken, S.; Blanche, P. -A.; Lemaire, P.; Legros, N.; Dekker, H. .; Monnet, G. Bibcode: 2001Msngr.106....6H Altcode: This article is a shortened, combined and updated version of papers given at the August 2001 SPIE conference on Gratings in Astronomy (Monnet et al., 2001 and Habraken et al., 2001). Title: The SUMER spectral atlas of solar-disk features Authors: Curdt, W.; Brekke, P.; Feldman, U.; Wilhelm, K.; Dwivedi, B. N.; Schühle, U.; Lemaire, P. Bibcode: 2001AIPC..598...45C Altcode: 2001sgc..conf...45C A far-ultraviolet and extreme-ultraviolet (FUV, EUV) spectral atlas of the Sun between 670 Å and 1609 Å in first order of diffraction has been derived from observations obtained with the SUMER (Solar Ultraviolet Measurements of Emitted Radiation) spectrograph on the spacecraft SOHO (Solar and Heliospheric Observatory) [1]. The atlas contains spectra of the average quiet Sun, a coronal hole and a sunspot on disk. Different physical parameters prevalent in the bright network (BN) and in the cell interior (CI)-contributing in a distinct manner to the average quiet-Sun emission-have their imprint on the BN/CI ratio, which is also shown for the entire spectral range. With a few exceptions, all major lines are given with their identifications and wavelengths. Lines that appear in second order are superimposed on the first order spectra, but below 500 Å the responsivity of the normal-incidence optical system is very low. The spectra include emissions from atoms and ions in the temperature range 6 103 K to 2 106 K, i.e., continua and mission lines emitted from the lower chromosphere to the corona. This spectral atlas, with its broad wavelength coverage, provides a rich source of new diagnostic tools for studying the physical parameters in the chromosphere, the transition region and the corona. In particular, the wavelength range below 1100 Å as observed by SUMER represents a significant improvement over the spectra produced in the past. In view of the manifold appearance and temporal variation of the solar atmosphere it is obvious that our atlas can only be a-hopefully typical-snapshot. The spectral radiances are determined with a relative uncertainty of 0.15 to 0.30 (1σ), and the wavelength scale is accurate to typically 10 mÅ, which is the level achievable with semi-automatic processing. The SUMER solar-disk spectral atlas will be published in the near future by Curdt et al. [2]. It includes profiles of the average quiet Sun, an equatorial coronal hole, and a sunspot. As an example we show in Fig. 1 the spectral range from 1300 Å to 1342 Å with the prominent O I and C II lines. Resolved emission lines are indicated by a mark, the measured wavelength in angstrom, and the identification, if available. Marks point to line lists available in the literature, where additional information about a specific line can be found [3-7]. New lines or identifications are indicated. Lines observed in first order and in second-order of diffraction are distinguished. Only the three least-significant digits of the wavelength values are given. If available, unidentified lines are characterized by the temperature classification defined in [3] (a: Te<3 105 b: Te~3 105 c: Te~4 105 d: 6 105<Te <9 105 e: Te~1.4 106 f: Te~1.8 106). The vertical axes are scaled to spectral radiance in units of mW sr-1 m-2 Å-1 on the left the radiometric calibration for first order lines is given, on the right for second order lines. Note, that second order lines are always superimposed on a first order background. We have taken care of the type of photocathode (bare or KBr) when applying the radiometric calibration to different sections of the spectrum. Also displayed in green is the BN/CI ratio in an attempt to characterize the quiet-Sun chromospheric network structure. A pre-print of the SUMER spectral atlas and a line list is available at http://www.linmpi.mpg.de/~curdt. . Title: Wide bandgap EUV and VUV imagers for the Solar Orbiter Authors: Hochedez, Jean-François; Lemaire, Philippe; Pace, Emanuele; Schühle, Udo; Verwichte, Erwin Bibcode: 2001ESASP.493..245H Altcode: 2001sefs.work..245H No abstract at ADS Title: The SUMER spectral atlas of solar-disk features Authors: Curdt, W.; Brekke, P.; Feldman, U.; Wilhelm, K.; Dwivedi, B. N.; Schühle, U.; Lemaire, P. Bibcode: 2001A&A...375..591C Altcode: A far-ultraviolet and extreme-ultraviolet (FUV, EUV) spectral atlas of the Sun between 670 Å and 1609 Å in the first order of diffraction has been derived from observations obtained with the SUMER (Solar Ultraviolet Measurements of Emitted Radiation) spectrograph on the spacecraft SOHO (Solar and Heliospheric Observatory). The atlas contains spectra of the average quiet Sun, a coronal hole and a sunspot on the disk. Different physical parameters prevalent in the bright network (BN) and in the cell interior (CI) - contributing in a distinct manner to the average quiet-Sun emission - have their imprint on the BN/CI ratio, which is also shown for almost the entire spectral range. With a few exceptions, all major lines are given with their identifications and wavelengths. Lines that appear in second order are superimposed on the first order spectra. These lines are clearly marked in the atlas. The spectra include emissions from atoms and ions in the temperature range 6*E3 K to 2*E6 K, i.e., continua and emission lines emitted from the lower chromosphere to the corona. This spectral atlas, with its broad wavelength coverage, provides a rich source of new diagnostic tools to study the physical parameters in the chromosphere, the transition region and the corona. In particular, the wavelength range below 1100 Å as observed by SUMER represents a significant improvement over the spectra produced in the past. In view of the manifold appearance and temporal variation of the solar atmosphere, it is obvious that our atlas can only be a - hopefully typical - snapshot. Brief descriptions of the data reduction and calibration procedures are given. The spectral radiances are determined with a relative uncertainty of 0.15 to 0.30 (1sigma ) and the wavelength scale is accurate to typically 10 mÅ. The atlas is also available in a machine readable form. Table A.1 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/375/591 Title: VizieR Online Data Catalog: SUMER Spectral Atlas of Solar Disk Features (Curdt+, 2001) Authors: Curdt, W.; Brekke, P.; Feldman, U.; Wilhelm, K.; Dwivedi, B. N.; Schuhle, U.; Lemaire, P. Bibcode: 2001yCat..33750591C Altcode: List of spectral lines in the wavelength range from 668Å to 1611Å identified in SUMER (Solar Ultraviolet Measurements of Emitted Radiation, spectrograph on the spacecraft SOHO) spectra of the average quiet Sun (QS), a coronal hole (CH) and a sunspot on disk (SS). Spectral lines observed in second order of diffraction which are also given here, extend the lower wavelength limit to below 500Å. For each entry we give the observed wavelengths in angstrom, the identification, the transition, the peak of spectral radiance, Lpeak, in mW/(sr*m2*Å) (incl. background), and a cross-reference to other line lists available in the literature (cf., Sect. 5.1). For second-order lines radiance entries are generally not provided, since the background separation in both orders of diffraction is a non-trivial task, which can not be automated. Only a few radiance values of strong second-order lines with negligible first-order contribution are given, which are marked by an asterisk (*). (1 data file). Title: Solar Chromospheric Plage Authors: Lemaire, P. Bibcode: 2000eaa..bookE2262L Altcode: Chromospheric plage (from the French 19th century wording: `plage brillante', bright plage or bright area) or facular plage (facula, Latin word for small torch) is a bright area seen in chromospheric lines most of the time surrounding one or several SUNSPOTS. Chromospheric plage is one of the main components of the solar activity (see SOLAR ACTIVE REGIONS).... Title: SUMER observations of transition region fine structures Authors: Landi, E.; Mason, H. E.; Lemaire, P.; Landini, M. Bibcode: 2000A&A...357..743L Altcode: The SUMER (Solar Ultraviolet Measurements of Emitted Radiation) instrument on SOHO (Solar and Heliospheric Observatory) provides an opportunity to observe and study the solar transition region with high spatial and spectral resolution. We present new evidence to confirm that the emission from the quiet Sun at 2x 105 K is dominated by cool loop-like fine structures which cluster across the chromospheric network boundaries. The electron density of these structures is found to be around 1010 cm-3. The red-shifts in spectral line profiles and the non-thermal widths from lines formed at this temperature are found to be correlated with intensity. The properties of explosive events with irregular profiles are explored. A large jet-like structure is analysed. The results of our analysis are compared with recent predictions from numerical models. Title: Polar Plumes and Inter-plume regions as observed by SUMER on SOHO Authors: Banerjee, D.; Teriaca, L.; Doyle, J. G.; Lemaire, P. Bibcode: 2000SoPh..194...43B Altcode: We present observations of O vi 1032 Å line profiles obtained with the SUMER instrument on SOHO extending from the solar disk to 1.5 R⊙ above the limb in the north polar coronal hole. Variations of the intensity and linewidth in the polar plume and inter-plume regions are investigated. We find an anti-correlation between the intensity and the linewidth in the plume and inter-plume regions with detailed plume structures been seen out to 1.5 R⊙. Possible implications regarding the magnetic topologies of these two regions and related heating mechanisms are discussed. The O vi linewidth measurements are combined with UVCS output to provide an overview of its variations with height extending up to 3.5 R⊙. We find a linear increase of the linewidth from 1 to 1.2 R⊙, then a plateau followed by a sharp increase around 1.5 R⊙. Title: Radiance variations of the quiet Sun at far-ultraviolet wavelengths Authors: Schühle, U.; Wilhelm, K.; Hollandt, J.; Lemaire, P.; Pauluhn, A. Bibcode: 2000A&A...354L..71S Altcode: We have measured the radiance of quiet-Sun areas at the centre of the solar disk using the vacuum-ultraviolet telescope-spectrograph SUMER (Solar Ultraviolet Measurements of Emitted Radiation) on the Solar and Heliospheric Observatory (SOHO). The radiances of selected emission lines have been measured from March 1996 to the present. The lines that have been observed regularly since the beginning of the SOHO mission are He i 584 Å, Mg x 609 Å and 624 Å, Ne viii 770 Å, N v 1238 Å, and the H i Lyman continuum at 880 Å. We investigate the variability of these emission lines during the solar minimum and the ascending phase of the present solar activity cycle. The transition region and coronal lines show an increasing trend of up to 100% since the sunspot minimum. The results are important for models of solar VUV variability on the basis of radiance contrast ratios of solar disk regions. Our spatially resolved images allow a separation of the network and cell areas of the quiet-Sun. Both regimes show similar variations. Title: Solar Irradiances of Ultraviolet Emission Lines Measured During the Minimum of Sunspot Activity in 1996 and 1997 Authors: Wilhelm, K.; Lemaire, P.; Dammasch, I. E.; Hollandt, J.; Schuhle, U.; Curdt, W.; Kucera, T.; Hassler, D. M.; Humbler, M. C. E. Bibcode: 2000PCEC...25..389W Altcode: No abstract at ADS Title: Radiometric Calibration of the Vacuum-Ultraviolet Spectrograph SUMER on the SOHO Spacecraft with the B Detector Authors: Schühle, Udo; Curdt, Werner; Hollandt, Jörg; Feldman, Uri; Lemaire, Philippe; Wilhelm, Klaus Bibcode: 2000ApOpt..39..418S Altcode: The Solar Ultraviolet Measurement of Emitted Radiation (SUMER) vacuum-ultraviolet spectrograph was calibrated in the laboratory before the integration of the instrument on the Solar and Heliospheric Observatory (SOHO) spacecraft in 1995. During the scientific operation of the SOHO it has been possible to track the radiometric calibration of the SUMER spectrograph since March 1996 by a strategy that employs various methods to update the calibration status and improve the coverage of the spectral calibration curve. The results for the A Detector were published previously Appl. Opt. 36, 6416 (1997) . During three years of operation in space, the B detector was used for two and one-half years. We describe the characteristics of the B detector and present results of the tracking and refinement of the spectral calibration curves with it. Observations of the spectra of the stars and Leonis permit an extrapolation of the calibration curves in the range from 125 to 149.0 nm. Using a solar coronal spectrum observed above the solar disk, we can extrapolate the calibration curves by measuring emission line pairs with well-known intensity ratios. The sensitivity ratio of the two photocathode areas can be obtained by registration of many emission lines in the entire spectral range on both KBr-coated and bare parts of the detector s active surface. The results are found to be consistent with the published calibration performed in the laboratory in the wavelength range from 53 to 124 nm. We can extrapolate the calibration outside this range to 147 nm with a relative uncertainty of 30% (1 ) for wavelengths longer than 125 nm and to 46.5 nm with 50% uncertainty for the short-wavelength range below 53 nm. Title: Radiance Variations of Vacuum-Ultraviolet Emission Lines of the Quiet Sun Observed with SUMER on SOHO Authors: Schuhle, U.; Pauluhn, A.; Hollandt, J.; Lemaire, P.; Wilhelm, K. Bibcode: 2000PCEC...25..429S Altcode: No abstract at ADS Title: Solar spectroradiometry with the telescope and spectrograph SUMER on the Solar and Heliospheric Observatory SOHO Authors: Wilhelm, K.; Schühle, U.; Curdt, W.; Dammasch, I. E.; Hollandt, J.; Lemaire, P.; Huber, M. C. E. Bibcode: 2000Metro..37..393W Altcode: No abstract at ADS 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: 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: On VI 1031.95 Å Line Polarization Measurements in View of Velocity Field and Magnetic Field Diagnostics in the Inner Solar Corona: Effect of the Polar Hole Authors: Raouafi, N. -E.; Sahal-Bréchot, S.; Lemaire, P. Bibcode: 1999ESASP.448.1205R Altcode: 1999ESPM....9.1205R; 1999mfsp.conf.1205R No abstract at ADS Title: The solar ultraviolet spectrum from 1200 Å to 1560 Å: a radiometric comparison between SUMER/SOHO and SOLSTICE/UARS Authors: Wilhelm, K.; Woods, T. N.; Schühle, U.; Curdt, W.; Lemaire, P.; Rottman, G. J. Bibcode: 1999A&A...352..321W Altcode: After short descriptions of the SUMER (Solar Ultraviolet Measurements of Emitted Radiation) spectrometer onboard SOHO (the Solar and Heliospheric Observatory) and the SOLSTICE (Solar-Stellar Irradiance Comparison Experiment) spectrometer on UARS (the Upper Atmosphere Research Satellite), a radiometric comparison is carried out of solar irradiance spectra measured by SOLSTICE and spectra derived from SUMER radiance observations of quiet-Sun regions in the wavelength range from 1200 Å to 1560 Å. The emission lines N v (lambda 1238) and C iv (lambda 1548) are considered in detail. For these lines, irradiance data are also available from full-Sun raster scans of SUMER and deviations of less than 15% are found between SOLSTICE and SUMER results - well within the combined uncertainty margins. Title: Structure and Role of the Transition Region Authors: Lemaire, P. Bibcode: 1999ESASP.446...35L Altcode: 1999soho....8...35L No abstract at ADS Title: On VI 103.2 A Line Polarization Measurements In View Of Velocity Field And Magnetic Field Diagnostics In The Inner Solar Corona Authors: Raouafi, N. -E.; Lemaire, P.; Sahal-Bréchot, S. Bibcode: 1999ESASP.446..567R Altcode: 1999soho....8..567R The linear polarization parameters of the O VI 103.2 nm coronal line are sensitive to the magnetic field and the solar wind velocity vector effects (via the Hanle effect and the Doppler dimming effect respectively). These parameters (degree and direction of linear polarization) are measured by interpreting observations taken by the SUMER spectrometer aboard of SOHO. SUMER is sensitive to the linear polarization state of the observed radiation. The profile and the shift of the O VI 103.2 nm and 103.7 nm lines and of the other lines measured during the observations will also be reported. These results should permit to obtain information on the velocity distribution of the coronal O VI ions. Title: The Off-Limb Behavior of the First Ionization Potential Effect in T>5×105 K Solar Plasmas Authors: Laming, J. M.; Feldman, U.; Drake, J. J.; Lemaire, P. Bibcode: 1999ApJ...518..926L Altcode: We investigate the behavior of the solar first ionization potential (FIP) effect (the abundance enhancement of elements with first ionization potential of less than 10 eV in the corona with respect to photospheric values) with height above the limb in a region of diffuse quiet corona observed by the SUMER instrument on SOHO, with emphasis on so-called upper transition region lines. Previous disk observations have shown different abundance patterns in emission from lines at temperatures above and below ~8×105 K, with an FIP effect clearly visible at the higher temperatures and less so at the lower temperatures. Our initial aim is to determine whether such a difference is also visible in off-limb observations. We find a low-FIP element enhancement of a factor of 3-4 indicated in all line ratios. The Mg VII 868.11/Ne VII 895.17 ratio is also seen to decrease toward a photospheric value when tracked down from the corona to the limb. This is markedly different from the behavior of higher temperature line ratios and may be related to the differing heating and mass supply mechanisms for plasmas at temperatures above and below ~8×105 K.

An additional unexpected feature of our observations is that in low-FIP/high-FIP line ratios formed at temperatures close to the freeze-in temperature of the fast solar wind (~106 K), there is also a small diminution of the FIP enhancement at the highest altitudes observed in this study. We discuss the possible relevance of this to the origin of the fast solar wind. Title: Detection of the O VI 103.2 NM line polarization by the SUMER spectrometer on the SOHO spacecraft Authors: Raouafi, N. -E.; Lemaire, P.; Sahal-Bréchot, S. Bibcode: 1999A&A...345..999R Altcode: The first detection of the O VI 103.2 nm line polarization has been performed in the corona by SUMER (Solar Ultraviolet Measurements of Emitted Radiation) on the SOHO (Solar Heliospheric Observatory). The polarization properties of the spectrometer was used to analyze the solar radiation in a coronal hole at about 270 arcsec above the south solar limb, during the SOHO spacecraft rotation of March 19, 1996. Taking advantage of the different behavior of the lines in the O VI doublet and of the nearby chromospheric lines we have been able to extract the weak signal modulation introduced by polarization from solar variations and telescope scattered light. The ~ 4% modulation rate (related to the linear polarization of the O VI 103.2 nm line) derived is an important clue to infer the properties of the local magnetic field strength and the velocity field in the coronal hole. 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: Doppler redistribution of resonance polarization of the O VI 103. 2 nm line observed above a polar hole Authors: Raouafi, N. -E.; Sahal-Bréchot, S.; Lemaire, P.; Bommier, V. Bibcode: 1999ASSL..243..349R Altcode: 1999sopo.conf..349R No abstract at ADS Title: Solar irradiances of UV and EUV lines during the minimum of the sunspot activity in 1996 Authors: Wilhelm, K.; Lemaire, P.; Dammasch, I. E.; Hollandt, J.; Schühle, U.; Curdt, W.; Kucera, T.; Hassler, D. M.; Huber, M. C. E. Bibcode: 1999AdSpR..24..229W Altcode: Full Sun observations in UV and EUV emission lines were performed by SUMER (Solar Ultraviolet Measurements of Emitted Radiation) on SOHO (Solar and Heliospheric Observatory) in 1996. The radiometric preflight calibration of SUMER is traceable to a primary radiometric source standard - the electron storage ring BESSY. Based on this calibration and on its inflight refinements, the irradiance values at SOHO have been obtained for the lines He i (λ584.33), O v (λ629.74), Ne viii (λ770.41), S v (λ786.47), O iv (λ787.72), S vi (λλ933.39, 944.52), H i Ly ɛ (λ937.80), C iii (λ977.04), N v (λ1238.81), Si i (λ1256.52), and C iv (λ1548.20), and the continuum near 1549 Å. In this contribution, we compare our measurements with other recent irradiance determinations and discuss, in particular, the observations in the C iv line. Title: Search for Signatures of a Coronal Hole in Transition Region Lines Near Disk Center Authors: Lemaire, P.; Bocchialini, K.; Aletti, V.; Hassler, D.; Wilhelm, K. Bibcode: 1999SSRv...87..249L Altcode: The analysis of data taken by SUMER near disk center, where a small coronal hole is observed in EIT images, is performed. From the measurements of Doppler non-thermal velocities and intensities, we search for the diagnostics and the signature of small scale structures in the coronal hole using transition region lines. Transition region lines in the range of 7 × 104 K to 2.5 × 105 K have a non-thermal velocity excess of 4.0 to 5.5 km s-1 relative to the contiguous quiet Sun. While the average intensity is lower in the coronal hole than in the quiet area, this result shows an increase of turbulence at the base of the high speed solar wind. Title: SUMER Measurements of Nonthermal Motions: Constraints on Coronal Heating Mechanisms Authors: Chae, Jongchul; Schühle, Udo; Lemaire, Philippe Bibcode: 1998ApJ...505..957C Altcode: We have determined nonthermal velocities in the quiet Sun at temperatures between 104 K and 2 × 106 K by measuring the widths of a number of EUV and far-ultraviolet (FUV) lines taken with SUMER on board the SOHO spacecraft. The broadenings owing to the SUMER instrument and the finite opacity in each line have been carefully examined. The nonthermal velocity at temperatures below 2 × 104 K is smaller than 10 km s-1. The velocity increases with temperature, reaches a peak value of 30 km s-1 around 3 × 105 K, and then decreases with the temperature. The coronal nonthermal velocity is about 20 km s-1. There exists a strong correlation between intensity and nonthermal velocity at temperatures 2 × 104-1 × 105 K. The correlation at higher temperatures weakens as temperature increases. Furthermore, there is a spatial correlation between the nonthermal velocities inferred from a set of any two lines with temperatures below 2 × 105 K. Neither significant center-to-limb variation nor meaningful dependence on the integration time was found from the measured nonthermal velocities. We have discovered the existence of high-velocity components in the observed S VI λ933.4 line profiles. The average nonthermal velocity and intensity fraction of this S VI line high-velocity component are found to be 55 km s-1 and 0.25, respectively.

Observational characteristics of nonthermal motions carry some problems that should be solved when interpreting observed nonthermal motions in terms of either unresolved loop flows or Alfvén waves. The isotropic and very small scale nature of the observed nonthermal motions appears to be suited to the MHD turbulence interpretation of nonthermal motions. The turbulent heating rates inferred from the measured nonthermal motions can account for the radiative loss throughout the transition region and corona if the nonthermal motions are truly turbulent motions whose mechanical energy is injected at a scale of 1000 km (Kolmogorov-type turbulence) or 15 km (Kraichnan-type turbulence). The existence of high-velocity components at temperatures 6 × 104-2 × 105 K appears as observational evidence supporting nanoflare heating at these temperatures. Title: The Si/Ne Abundance Ratio in Polar Coronal Hole and Quiet-Sun Coronal Regions Authors: Doschek, G. A.; Laming, J. M.; Feldman, U.; Wilhelm, K.; Lemaire, P.; Schühle, U.; Hassler, D. M. Bibcode: 1998ApJ...504..573D Altcode: Using spectra obtained from the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer flown on the Solar and Heliospheric Observatory (SOHO) spacecraft, we determine the Si/Ne abundance ratio in diffuse, interplume polar coronal hole regions, as well as the ratio relative to quiet-Sun coronal regions. Ne has the second highest first ionization potential (FIP) of solar abundant elements, and Si is a low-FIP element. Thus the Si/Ne ratio is a sensitive indicator of abundance variations due to the FIP effect. We develop new spectroscopic diagnostics for the determination of the Si/Ne abundance ratio. Assuming ionization equilibrium, we find that the Si/Ne abundance ratio in interplume polar coronal hole regions is about a factor of 2 greater than the photospheric value and is close to or the same as in coronal quiet-Sun regions. This result pertains to the electron temperature range 5-8 × 105 K. However, the combined atomic physics, instrumental, and statistical uncertainty in this result is about a factor of 2, and therefore this observed enhancement is consistent with no enhancement in the polar hole abundances. Nevertheless, our results follow the same trend, i.e., a greater than photospheric abundance ratio of low-FIP elements in the corona relative to high-FIP elements, as found from other abundance measurements in the corona that involve different atomic physics and different instruments. Therefore we feel that our results reflect an actual abundance enhancement, despite being within an uncertainty level bar that encompasses photospheric abundances. We also examine the Ne/Mg abundance ratio over a 24.5 hr observation and find no significant abundance variations. (Mg is a low-FIP element.) Thus, no large transient abundance variations appear to occur on timescales shorter than about a day, although this result is based on only one observation. From lines of Mg VII, Mg VIII, Mg IX, and Mg X we find that the electron temperature along the line of sight increases with height above the limb over the polar coronal holes, as has been previously reported. We determine the emission measure distribution as a function of height from Mg VII, Mg VIII, and Mg X lines. We determine average temperatures along the line of sight over the polar holes from Ne VIII/Ne VII, Mg VIII/Mg VII, and Si VIII/Si VII line ratios. We also discuss the temperature properties of the coronal hole and quiet-Sun regions using forbidden lines of Fe X and Fe XI. We comment on the possibility that ionization equilibrium is not valid in polar coronal hole regions, a possible scenario in light of recent observations that show outflows in coronal holes beginning at about the temperature of formation of Ne VIII. Title: High-Temperature Lines in SUMER Spectra Recorded Above a Bright Solar Active Region Authors: Feldman, U.; Curdt, W.; Doschek, G. A.; Schühle, U.; Wilhelm, K.; Lemaire, P. Bibcode: 1998ApJ...503..467F Altcode: We identify spectral lines emitted by solar abundant elements due primarily to transitions within the 2s22pk and 3s23pk (where k = 1, 5) ground configurations of ions that are formed in ionization equilibrium between 2 × 106 and 8 × 106 K. The transitions were identified in spectra of a bright active region recorded 1997 September 6, by the Solar Ultraviolet Measurements of Emitted Radiation Spectrometer (SUMER) flown on the Solar and Heliospheric Observatory (SOHO). Some of these lines provide useful plasma diagnostic tools for measuring the physical conditions in the solar corona. Title: Measurement of the electron temperature gradient in a solar coronal hole Authors: David, C.; Gabriel, A. H.; Bely-Dubau, F.; Fludra, A.; Lemaire, P.; Wilhelm, K. Bibcode: 1998A&A...336L..90D Altcode: It has long been established that the high speed solar wind streams observed at 1 A.U. originate from the coronal hole regions of the Sun. Theoretical modelling of the acceleration mechanism depends critically on the value of the maximum of temperature existing close to the Sun. Measurements of the temperature in coronal holes prior to SOHO are unreliable. The very low luminosity leads to extreme observational difficulties, in particular due to light scattering in the instrument telescopes. Using the two SOHO spectrometers CDS and SUMER, electron temperatures have now been measured as a function of height above the limb in a polar coronal hole. Temperatures of around 0.8 MK are found close to the limb, rising to a maximum of less than 1 MK at 1.15 R_sun, then falling to around 0.4 MK at 1.3 R_sun. With these low temperatures, the classical Parker mechanism cannot alone explain the high wind velocities, which must therefore be due to the direct transfer of momentum from MHD waves to the ambient plasma. Title: Solar irradiances and radiances of UV and EUV lines during the minimum of sunspot activity in 1996 Authors: Wilhelm, K.; Lemaire, P.; Dammasch, I. E.; Hollandt, J.; Schuehle, U.; Curdt, W.; Kucera, T.; Hassler, D. M.; Huber, M. C. E. Bibcode: 1998A&A...334..685W Altcode: Full Sun observations in UV and EUV emission lines were performed by SUMER (Solar Ultraviolet Measurements of Emitted Radiation) on SOHO (Solar and Heliospheric Observatory) in 1996. The radiometric pre-flight calibration of SUMER is traceable to a primary radiometric source standard - the electron storage ring BESSY. Based on this calibration, the irradiance values at SOHO and at 1 AU have been obtained for the lines He i (lambda 584.33 { Angstroms}), O v (lambda 629.74 { Angstroms}), Ne viii (lambda 770.41 { Angstroms}), S v (lambda 786.47 { Angstroms}), O iv (lambda 787.72 { Angstroms}), S vi (lambda lambda 933.39, 944.52 { Angstroms}), H i Ly epsilon (lambda 937.80 { Angstroms}), C iii (lambda 977.04 { Angstroms}), N v (lambda 1238.81 { Angstroms}), Si i (lambda 1256.52 { Angstroms}), and C iv (lambda 1548.20 { Angstroms}). The spatially resolved measurements allowed good estimates to be made of the active region contributions to the irradiance of the quiet Sun. The centre-to-limb radiance variations of these lines have also been obtained from these measurements. For quiet solar conditions, a radiance spectrum was determined for wavelengths from 800 { Angstroms} to 1500 { Angstroms} near the centre of the solar disk. Title: The Solar Corona Above Polar Coronal Holes as Seen by SUMER on SOHO Authors: Wilhelm, Klaus; Marsch, Eckart; Dwivedi, Bhola N.; Hassler, Donald M.; Lemaire, Philippe; Gabriel, Alan H.; Huber, Martin C. E. Bibcode: 1998ApJ...500.1023W Altcode: In order to address two of the principal scientific objectives of the Solar and Heliospheric Observatory (SOHO), studies of the heating mechanisms of the solar corona and the acceleration processes of the solar wind, we deduce electron temperatures, densities, and ion velocities in plumes and interplume regions of polar coronal holes using ultraviolet observations from SUMER (Solar Ultraviolet Measurements of Emitted Radiation) on SOHO. SUMER allows us to study the inner corona up to a distance of about 430,000 km above the limb, or r = 1.6 R⊙ (solar radius) from the center of the disk. We find the electron temperatures, Te, to be less than 800,000 K in a plume in the range from r = 1.03 to 1.60 R⊙, decreasing with height to ~330,000 K. Near an interplume lane, the electron temperature is also low, but stays between 750,000 and 880,000 K in the same height interval. Doppler widths of O VI lines in plumes are narrower (ΔλD ~ 150 mÅ, v1/E ~ 43 km s-1) than in interplume lanes (~190 mÅ, ~55 km s-1). The thermal and turbulent ion speeds, v1/E, of Si7+ reach values up to ~80 km s-1 in the darkest regions outside plumes above the coronal hole. This corresponds to a kinetic ion temperature of 1 × 107 K. A limit of ~18 km s-1 for the bulk speed in plumes below r = 1.2 R⊙ is deduced from O VI line shift measurements and consideration of the three-dimensional plume geometry (differential line-of-sight velocities <=3 km s-1), whereas differential line-of-sight velocities of Mg8+ ions up to 34 km s-1 can be seen in dark regions. Title: Solar H i Lyman alpha full disk profile obtained with the SUMER/SOHO spectrometer Authors: Lemaire, P.; Emerich, C.; Curdt, W.; Schuehle, U.; Wilhelm, K. Bibcode: 1998A&A...334.1095L Altcode: An uncalibrated solar hydrogen Lyman alpha profile was obtained with the use of the spectrometer on SOHO. The collection of the light scattered by the telescope permitted to average the profile over the full solar disk. The profile taken at the L1 Sun-Earth Lagrangian position is free of the central geocoronal absorption. Then, taking advantage of the absolute flux measured by the SOLSTICE/UARS spectrometer, an absolute line profile intensity is derived, and is compared with previous observations at minimum solar activity. Title: The Magnetic Reconnection Explorer (MAGREX) Authors: Schühle, U.; Antionchos, S. K.; Barbee, T. W., Jr.; Bixler, J. V.; Brown, C. M.; Carter, P. H., II; Curdt, W.; Davila, J. M.; Doschek, G.; Feldman, U.; Goldstein, W. H.; Kordas, J.; Lemaire, P.; Mariska, J. T.; Marsch, E.; Moses, J. D.; Seely, J. F.; Wilhelm, K.; Woods, T. N. Bibcode: 1998ESASP.417..289S Altcode: 1998cesh.conf..289S 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: New Requirements for Transition Region to Low Corona Observations with FUV-EUV Spectrometers Derived from SOHO Experience Authors: Lemaire, P. Bibcode: 1998ESASP.417..325L Altcode: 1998cesh.conf..325L No abstract at ADS Title: Instrumentation: Spectroscopy Authors: Lemaire, Philippe Bibcode: 1998LNP...507..245L Altcode: 1998sspt.conf..245L Our knowledge of the the solar atmosphere comes from the light analysis. The ultraviolet wavelength is the privileged spectral range to study the solar plasma in several stages of ionization emitted from the chromosphere to the corona. Starting with basic notions of spectroscopy, an overview of important parameters is given. Then, after a short description of classical spectrometers, a detailed analysis of the properties of the mountings used on SOHO is performed; some examples are shown. I discuss how to separate the real solar signal from the instrumental contribution. Title: The solar disk spectrum between 660 and 1175 Anstroms (first order) obtained by SUMER on SOHO Authors: Curdt, W.; Feldman, U.; Laming, J. M.; Wilhelm, K.; Schuehle, U.; Lemaire, P. Bibcode: 1997A&AS..126..281C Altcode: SUMER -- Solar Ultraviolet Measurements of Emitted Radiation -- onboard of SOHO -- Solar and Heliospheric Observatory -- obtained its first spectrum on January 25, 1996 near the north polar limb. The range from 660 Angstroms to 1175 Angstroms which has never before been observed with such a good spectral resolution contains a wealth of spectroscopic details. Identification of about 400 lines in this spectral range is given. We list the wavelengths of identified transitions and provide their absolute peak intensities. General spectral features of the most abundant elements H, He, C, N, O, Ne, Mg, Si, S, Ar, and Fe are described. In this spectral range many density- and temperature-sensitive line pairs are found. It is shown in examples how they can be used as diagnostic tools. Table 1 and Fig.nearlimb are also available in digital form at the CDS via anonymous ftp to cdsarc.u-strasbg. fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html Title: The Off-Limb Behaviour of the Solar Transition Region FIP Effect Authors: Laming, J. M.; Feldman, U.; Drake, J. J.; Schuhle, U.; Curdt, W.; Wilhelm, K.; Lemaire, P. Bibcode: 1997AAS...191.7301L Altcode: 1997BAAS...29.1320L We investigate the behaviour of the solar FIP effect (the abundance enhancement of elements with first ionization potential < 10 eV by factor of 3-4 in the corona with respect to photospheric values) with height above the limb in a region of diffuse quiet corona observed by the SUMER instrument on SOHO. Line ratios formed at log T > 5.8 show coronal abundances for all heights. Line ratios formed at lower temperatures are consistent with coronal abundances well off the limb, with the apparent magnitude of the FIP enhancement decreasing by a factor of 1.5 - 2 as one approaches the solar limb. Thus our observations support a spatial variation in the quiet sun transition region FIP effect inferred previously from studies of the full disk solar spectrum (Laming, Drake, & Widing 1995, ApJ, 443, 416 and references therein). This result adds to the probability that emission from the solar disk transition region and corona originates from qualitatively different structures for values of log T {<atop >} 5.8, having different FIP effects. Title: A Coronal Spectrum in the 500--1610 Angstrom Wavelength Range Recorded at a Height of 21,000 Kilometers above the West Solar Limb by the SUMER Instrument on Solar and Heliospheric Observatory Authors: Feldman, U.; Behring, W. E.; Curdt, W.; Schühle, U.; Wilhelm, K.; Lemaire, P.; Moran, T. M. Bibcode: 1997ApJS..113..195F Altcode: We present a solar coronal spectrum recorded by the extreme UV spectrometer SUMER on the Solar and Heliospheric Observatory. The spectrum was taken between 21:28 UT on 1996 June 25 and 02:47 UT on 1996 June 26, at a height of 21,000 km above the west equatorial limb with the slit oriented in the north-south direction. At the time of the observations the Sun was rather quiet, and the west limb appeared ``devoid of any activity.'' The spectrum, which covers the 500-1610 Å wavelength range, originates from plasmas with temperatures ranging between 1.5 × 104 and 1.5 × 106 K. Identification of lines originating from different temperature regimes is facilitated by the appearance of their intensity along the 300" long slit.

Well over 800 lines have been found, many of which were not previously observed. We present the entire spectrum and discuss line identifications. A table of the wavelengths of lines observed, with their identifications and peak intensities, is provided. Although we have identified lines previously detected in laboratory plasmas and a number of new lines not previously observed, over 40% of the SUMER lines remain unidentified. Among the newly detected lines, some have a potential as plasma density diagnostics. Title: Observations of Polar Plumes with the SUMER Instrument on SOHO Authors: Hassler, D. M.; Wilhelm, K.; Lemaire, P.; Schühle, U. Bibcode: 1997SoPh..175..375H Altcode: We present new observations of O vi 1032 Å line profiles in polar plumes, and inter-plume regions, on the disk and above the limb in the north coronal hole obtained with the SUMER (Solar Ultraviolet Measurements of Emitted Radiation) instrument on the SOHO (Solar and Heliospheric Observatory) spacecraft. On 22 May 1996, a 5 x 5 arc min spectroheliogram was scanned above the north polar coronal hole with the entrance slit extending from 1.03 to 1.33 solar radii with 1.5 arc sec spatial resolution and ≈ 0.044 Å per pixel spectral resolution in the wavelength range 1020-1040 Å. Detailed plume structure in O vi 1032 Å can be seen extending beyond 1.3 solar radii, with intensities in the plume regions 10-50% brighter, but line widths 10-15% narrower, than the inter-plume regions. Possible explanations for this observed anti-correlation between line width and intensity in the plume and inter-plume regions are discussed. We conclude that the source of the high-speed solar wind may not be polar plumes, but the inter-plume lanes associated with open magnetic field regions of the chromospheric network. Title: Radiometric calibration of SUMER: refinement of the laboratory results under operational conditions on SOHO Authors: Wilhelm, Klaus; Lemaire, Philippe; Feldman, Uri; Hollandt, Jörg; Schühle, Udo; Curdt, Werner Bibcode: 1997ApOpt..36.6416W Altcode: No abstract at ADS Title: Electron Density Diagnostics for the Solar Upper Atmosphere from Spectra Obtained by SUMER/SOHO Authors: Laming, J. M.; Feldman, U.; Schühle, U.; Lemaire, P.; Curdt, W.; Wilhelm, K. Bibcode: 1997ApJ...485..911L Altcode: We evaluate the electron density in various solar regions above the limb observed by the Solar Ultraviolet Measurement of Emitted Radiation (SUMER) instrument on SOHO. We find in general good agreement among line ratios from Be-, B-, N-, and Mg-like ions, giving densities of order 108 cm-3. Title: Turbulent Velocities and Ion Temperatures in the Solar Corona Obtained from SUMER Line Widths Authors: Seely, J. F.; Feldman, U.; Schühle, U.; Wilhelm, K.; Curdt, W.; Lemaire, P. Bibcode: 1997ApJ...484L..87S Altcode: Turbulent plasma velocities and ion temperatures were determined from the line widths recorded by the Solar Ultraviolet Measurements of Emitted Radiation instrument on the Solar and Heliospheric Observatory spacecraft. From the widths of the lines of five light elements (Ne, Na, Mg, Si, and S) and a heavy element (Fe), it was possible to determine the contributions of turbulent plasma motion and ion thermal motion to the line widths. The results indicated that the turbulent velocity was approximately 22 km s-1 at 30" above the limb and decreased to less than 10 km s-1 at 109" and 209" above the limb. At 30" above the limb, the ion temperatures of the hotter lines were comparable to the electron temperatures for ionization equilibrium. The ion temperatures of the cooler lines were higher than the ionization equilibrium temperatures; at 109" and 209" above the limb, the ion temperatures were at least a factor of 2.5 higher than the ionization equilibrium temperatures. Title: Doppler Shifts and Nonthermal Broadening in the Quiet Solar Transition Region: O VI Authors: Warren, H. P.; Mariska, J. T.; Wilhelm, K.; Lemaire, P. Bibcode: 1997ApJ...484L..91W Altcode: Using observations from the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) experiment flown on the Solar and Heliospheric Observatory (SOHO) spacecraft, we have measured Doppler wavelength shifts and nonthermal broadening in the 1032 and 1038 Å emission lines of O VI and the 1036 and 1037 Å emission lines of C II. Near Sun center the C II lines exhibit an average redshift of 2 +/- 3 km s-1, consistent with earlier observations in this temperature range. The O VI emission lines exhibit average Doppler velocities of 5 +/- 3 km s-1, suggesting the presence of redshifted material at 2.9 × 105 K. For the O VI lines, the average nonthermal component of the observed line width is 34 +/- 3 km s-1. Title: Electron Densities in the Solar Polar Coronal Holes from Density-Sensitive Line Ratios of Si VIII and S X Authors: Doschek, G. A.; Warren, H. P.; Laming, J. M.; Mariska, J. T.; Wilhelm, K.; Lemaire, P.; Schühle, U.; Moran, T. G. Bibcode: 1997ApJ...482L.109D Altcode: We derive electron densities as a function of height in the north and south polar coronal holes from a forbidden spectral line ratio of Si VIII. Si VIII is produced at about 8 × 105 K in ionization equilibrium. We also derive densities from a similar line ratio of S X (1.3 × 106 K). The spectra were obtained with the Solar Ultraviolet Measurements of Emitted Radiation spectrometer flown on the Solar and Heliospheric Observatory spacecraft. In addition to the primary mechanism of electron impact excitation, the derivation of theoretical level populations for Si VIII and S X includes both proton and resonance capture excitation. We compare the coronal hole results to quiet-Sun coronal measurements obtained outside the east and west limbs. We find for distances of a few arcseconds outside the solar limb that the average line-of-sight electron densities in the coronal holes are about a factor of 2 lower than in quiet-Sun regions. The decrease of density with height is exponential in the polar holes. We also confirm the result known from a variety of earlier observations that the temperature of most of the plasma in coronal holes does not exceed about 106 K. Title: Translimb Spectroscopy with SOHO/SUMER Authors: Ayres, T. R.; Lemaire, P.; Schuhle, U.; Wilhelm, K.; Ruedi, I.; Solanki, S. Bibcode: 1997SPD....28.0104A Altcode: 1997BAAS...29..879A We have used SUMER to obtain deep exposures of the 1300--1400 Angstroms spectrum, at the extreme limb and off-limb. Previous ``translimb'' studies in the thermal infrared had revealed remarkable extensions of cold material (T ~ 3000 K)---traced by carbon monoxide emission lines---into the heart of the hot chromosphere. A main objective of our program was to search for corresponding far-UV signatures of the ``thermally-bifurcated'' low chromosphere; for example, radiatively fluoresced emissions of the CO A--X 4th-positive system (collisional excitation would be negligible in cold gas). We conducted two separate observing programs with SUMER. Both made use of the 1('') -diameter circular aperture, translated across the limb in the minimum motor step increments of 0.('') 375, along the central meridian in the Northern polar coronal hole. The first program executed for nine hours beginning 19UT 25 Oct 1996. The full wavelength range was 1340--1400 Angstroms. It was recorded in two overlapping segments, placing key regions of the spectrum alternately on the KBr and bare parts of the detector, to help isolate 2nd-order features. Each segment was integrated for 500 s, and 32 pairs were obtained to span a 12('') swath centered on the optical limb. The second program was conducted 00--09UT 01 Dec 1996. It consisted of a single wavelength setting (1300--1340 Angstroms) with exposure time 500 s, but twice the spatial coverage of the earlier series: 64 steps, for a total displacement of 24('') . The strong chromospheric resonance lines of atomic oxygen (1302--1305 Angstroms) and ionized carbon (1334--1335 Angstroms) were observed on the bare part of the MCP camera. We report our progress in cataloging the rich, diverse translimb emission spectrum; and our efforts to deduce fundamental properties of the thermally heterogeneous chromosphere. [-3mm] SOHO is a project of international cooperation; the participation of TRA was supported by NASA grant NAG5-3226. Title: The Electron Density, Temperature, and Si/Ne Abundance Ratio in Polar Coronal Holes from SUMER Authors: Doschek, G. A.; Laming, J. M.; Warren, H. P.; Lemaire, P.; Wilhelm, K. Bibcode: 1997SPD....28.0404D Altcode: 1997BAAS...29Q.908D The Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer flown on the Solar and Heliospheric Observatory (SOHO) covers a wavelength range with spectral and spatial resolution and sensitivity not previously obtained by any other solar spectrometer experiment. Consequently, new plasma diagnostic techniques have been used and developed to measure plasma parameters such as electron density. In this paper we discuss the electron density as a function of height above the solar surface in the polar coronal holes as determined from line ratios of Si VIII and S X. The densities vary between about 3 x 10(6) cm(-3) and 10(8) cm(-3) . We determine the emission measure at selected temperatures as a function of position above the polar limbs from lines of Mg VII, Mg VIII, Mg IX, and Mg X. The electron temperature is lower in the polar holes than in the quiet Sun. This result is also based on intensities of lines of Fe X, Fe XI, and Fe XII. We determine the Si/Ne abundance ratio (low/high first ionization potential elements) using lines of Ne VII, Ne VIII, Si VII, and Si VIII. The preliminary result is that the Si/Ne abundance ratio in interplume regions is close to photospheric. We also compare the coronal hole density and abundance results with similar results obtained for the quiet Sun in the east and west coronal streamers. We discuss our conclusions in light of results from previous missions. Title: New Insights into the Physical Mechanisms of Polar Plumes with Observations from the SUMER Instrument on SOHO Authors: Hassler, Donald M.; Wilhelm, Klaus; Lemaire, Philippe; Schuehle, Udo Bibcode: 1997SPD....28.0802H Altcode: 1997BAAS...29..912H SUMER (Solar Ultraviolet Measurements of Emitted Radiation) line profiles above the limb in coronal holes are important for constraining thermodynamic models governing the outflow of the solar wind. Observational constraints in terms of thermal and nonthermal velocities, and upper limits on wave velocity amplitudes can be directly compared with in-situ observations. We present new observations of line profiles in polar plumes, and inter-plume regions, above the limb in coronal holes obtained with the SUMER instrument on the SOHO spacecraft. Detailed structure can be seen extending beyond 1.5 solar radii (out to the edge of the SUMER field-of-view), with intensities in the plume regions roughly 10-50% brighter than the inter-plume regions, but line widths in the plumes roughly 10% narrower than the inter-plume regions. Possible explanations for this observed anti-correlation between line width and intensity, and the correspondence with observed in-situ solar wind signatures will be discussed. Title: Observations of Doppler Shifts and Nonthermal Broadening in the North Polar Coronal Hole and Adjacent Quiet Sun Authors: Mariska, J. T.; Warren, H. P.; Wilhelm, K.; Lemaire, P. Bibcode: 1997SPD....28.0118M Altcode: 1997BAAS...29..882M Coronal holes are thought to be the source of high-speed solar wind streams. It is, however, unclear at what height the outflow of material first becomes apparent. Using the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) experiment on the Solar and Heliospheric Observatory (SOHO), we have obtained observations in the north polar coronal hole, its boundary region, and the adjacent quiet Sun at wavelengths that cover emission lines of O VI at 1032 and 1038 Angstroms, Ne VIII at 770 Angstroms, and Mg X at 625 Angstroms. These lines are formed at temperatures of 0.3, 0.8, and 1.25 MK, respectively, and should thus help to determine the temperature at which outflows are first detected. For O VI and Mg X, we will report on Doppler shift measurements made relative to cooler chromospheric lines. Since there are no suitable emission lines from ions formed in the chromosphere for the Ne VIII line, we are only able to measure relative differences between the coronal hole and the adjacent quiet Sun. We will also report on the magnitude of the nonthermal broadening in these lines in the different solar regions. This work was supported by a NASA SOHO Guest Investigator Program grant. Title: Doppler Shifts and Nonthermal Broadening in the Quiet Solar Transition Region: O VI Authors: Warren, H. P.; Mariska, J. T.; Wilhelm, K.; Lemaire, P. Bibcode: 1997SPD....28.0117W Altcode: 1997BAAS...29..882W Using observations from the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) experiment flown on the Solar and Heliospheric Observatory (SOHO ) spacecraft, we have measured Doppler wavelength shifts and nonthermal broadening in the 1032 and 1038 Angstroms emission lines of Ovi and the 1036 and 1037 Angstroms emission lines of Cii. Near Sun center the Cii lines exhibit an average redshift of 2+/-3km s(-1) , consistent with earlier observations in this temperature range. The Ovi emission lines exhibit average Doppler velocities of 5+/-3km s(-1) suggesting the presence of redshifted material at 2.9*E(5) K. For the Ovi lines, the average nonthermal component of the observed line width is 34+/-3km s(-1) . These observations indicate a tendency for brighter regions to have larger average redshifts and line widths than faint features although the relationship is very weak. Preliminary analysis of observations at the limb suggests that the Doppler velocities for Ovi do not approach zero as would be expected for predominately radial motions. Title: VizieR Online Data Catalog: Solar disk spectrum (660-1175A) (Curdt+ 1997) Authors: Curdt, W.; Feldman, U.; Laming, J. M.; Wilhelm, K.; Schuehle, U.; Lemaire, P. Bibcode: 1997yCat..41260281C Altcode: The near-limb quiet-Sun spectrum recorded on January 25, 1996 near the solar North pole is presented in tabular form and in graphical form. Table 1 - the line list - lists all lines found in the spectrum providing absolute peak intensities, measured and literature wavelengths, identification, and classification of the transition. Fig. 4 is a display the composite spectrum. The most prominent lines are labelled. In this figure intensities are given in instrumental units and logarithmic scale. (1 data file). Title: Determination of the Formation Temperature of Si IV in the Solar Transition Region Authors: Doschek, G. A.; Mariska, J. T.; Warren, H. P.; Wilhelm, K.; Lemaire, P.; Kucera, T.; Schühle, U. Bibcode: 1997ApJ...477L.119D Altcode: Using spectra obtained with the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer flown on the Solar and Heliospheric Observatory spacecraft, we deduce the temperature of formation of the Si IV ion in the solar transition region from the Si IV ultraviolet spectral line intensity ratio, 3p 2P3/2-3d 2D3/2,5/2/3s 2S1/2-3p 2P1/2, and compare the result to the temperature predicted under the assumption of ionization equilibrium. The wavelengths are as follows: 2D3/2,5/2, 1128.325, 1128.340 Å 2P1/2, 1402.770 Å. Ratios are derived for typical features of the quiet Sun, such as cell center and network, and are systematically higher than those predicted at the 6.3 × 104 K ionization equilibrium temperature of formation of Si IV. For most solar features the ratios imply a temperature of formation of about 8.5 × 104 K. The ratios for the faintest features imply a temperature of formation of up to 1.6 × 105 K. It is not clear, however, that all the discrepancies between the measured and theoretical ratios are due to a temperature effect. Accurate temperature measurements are important since a large discrepancy from ionization equilibrium has significant implications for the physics of the transition region, such as the possible presence of nonthermal electrons. Title: Working Group 2: Flows of Mass, Momentum and Energy Authors: Lemaire, P. Bibcode: 1997ESASP.404..131L Altcode: 1997cswn.conf..131L No abstract at ADS Title: First Results from SOHO on Waves Near the Solar Transition Region Authors: Steffens, S.; Deubner, F. -L.; Fleck, B.; Wilhelm, K.; Schuhle, U.; Curdt, W.; Harrison, R.; Gurman, J.; Thompson, B. J.; Brekke, P.; Delaboudiniere, J. -P.; Lemaire, P.; Hessel, B.; Rutten, R. J. Bibcode: 1997ASPC..118..284S Altcode: 1997fasp.conf..284S We present first results from simultaneous observations with the CDS, EIT and SUMER instruments {please see Solar Physics 162 (1995) for a description of the instruments} onboard SOHO and the VTT at Tenerife. Our aim is to study the wave propagation, shock formation, and transmission properties of the upper chromosphere and transition region. The preliminary results presented here include the variation of velocity power spectra with height, difference in power between internetwork and network regions, and variations in mean flows displayed by different spectral lines. Title: A New Look at the Quiet Sun Network in the Upper Atmosphere During a Minimum of Activity Cycle Authors: Lemaire, P.; Schuehle, U.; Curdt, W.; Wilhelm, K.; Poland, A.; Falciani, R. Bibcode: 1997ESASP.404..517L Altcode: 1997cswn.conf..517L 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 × 106 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: SOHO observations of the north polar solar wind Authors: Peres, G.; Ciaravella, A.; Betta, R.; Orlando, S.; Reale, F.; Kohl, J.; Noci, G.; Fineschi, S.; Romoli, M.; Brekke, P.; Fludra, A.; Gurman, J. B.; Lemaire, P.; Schuhle, U. Bibcode: 1997ESASP.404..587P Altcode: 1997cswn.conf..587P No abstract at ADS 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: Polarization sensitivity of the SUMER instrument on SOHO Authors: Hassler, D. M.; Lemaire, P.; Longval, Y. Bibcode: 1997ApOpt..36..353H Altcode: No abstract at ADS 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: Building the Spectrum of a G2V Star During a Minimum of Activity Cycle Authors: Lemaire, P.; Schuehle, U.; Curdt, W.; Wilhelm, K.; Hassler, D. Bibcode: 1997ESASP.404..513L Altcode: 1997cswn.conf..513L No abstract at ADS 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: Coordinated SOHO Observations of Polar Plumes Authors: Deforest, C. E.; Scherrer, P. H.; Tarbell, T.; Harrison, R. A.; Fludra, A.; Delaboudiniere, J. P.; Gurman, J. B.; Wilhelm, K.; Lemaire, P.; Hassler, D. M.; Kohl, J. L.; Noci, G.; Fineschi, S.; Brueckner, G. E.; Howard, R. A.; Cyr, O. C. St. Bibcode: 1996AAS...188.4909D Altcode: 1996BAAS...28R.898D On 7 and 8 March 1996, SOHO instruments engaged in their first joint science operation, a 12-hr observation of polar plumes over the South polar coronal hole. The observing mini-campaign included observations from SOHO, other spacecraft, and ground-based observatories. Contributing SOHO instruments -- in order of altitude, MDI, CDS, SUMER, EIT, UVCS, and LASCO -- made overlapping, simultaneous observations of plume structures from the photosphere out to the LASCO C3 limit of 32 solar radii. MDI provided line-of-sight surface magnetograms with a one-min cadence and 0.6 arcsec resolution; CDS, SUMER, and EIT supplied temperature-sensitive images of the lower corona with varying cadences and resolutions; UVCS measured fluctuations in Ly B intensity across the coronal hole with a one-min cadence at 1.4 R0; and LASCO imaged the entire corona out to 30 R0 in various visible passbands. Plume footpoints in the lower corona are observed by EIT and CDS to vary by a factor of two in EUV brightness with a timescale of tens of minutes, while the structures above are (as as been previously observed) quiescent on at least a ten-hr time scale. We present preliminary results of cross-instrument analysis of the observed plumes, and suggest how this and similar future data sets can be used to constrain quiet-sun wind acceleration and coronal heating models for the coronal hole. This research is supported by the SOI-MDI NASA contract NAG5-3077 at Stanford University. SOHO is project of international cooperation between NASA and ESA. Title: A Solar EUV Spectral Atlas Observed with SUMER Authors: Brekke, P.; Wilhelm, K.; Lemaire, P.; Curdt, W.; Schuhle, U.; Poland, A.; Kucera, T.; Hassler, D. M.; Siegmund, O. H. W. Bibcode: 1996AAS...188.3713B Altcode: 1996BAAS...28..879B We present the first solar EUV spectral atlas in the wavelength range 500 -- 1600 { Angstroms}. The spectra were recorded with the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) which is part of the ESA/NASA Solar and Heliospheric Observatory (SOHO). The solar spectrum below 1200 { Angstroms} is not very well known. Thus, the present spectral atlas, and SUMER observations in general, represents a new important diagnostic tool to study essential physical parameters of the solar atmosphere. It includes emission from atoms and ions in the temperature range 10(4) to 2 x 10(6) K. Thus, emission lines and continua emitted from the lower chromosphere to the lower corona can be studied. The atlas is also useful as a planning tool for SUMER studies to determine useful dwell times, possible blends, and to select proper data extraction windows. The angular resolution of SUMER is close to 1 arcsec, but the atlas presented here represents an average along part of the 1-arcsec wide slit, typically 30 arcsec. The spectral resolving power of the instrument is lambda /Delta lambda = 17770-38300. For more details about the SUMER instrument we refer to Wilhelm et al. (Solar Physics, 162, 189, 1995). The spectral data in this atlas were obtained with the spectrometer slit positioned at the center of the solar disk with a dwell time of 300 s to bring up weak lines and continua. The full spectral range was put together from a number of exposures each covering approximately 20 { Angstroms} in 1st order on the coated, and therefore most sensitive, part (KrB) of the detector. 1st and 2nd order spectra are superimposed. The spectral atlas is available in a computer readable format together with a IDL program to read and display the data using a widget interface. The atlas and the programs can be obtained via the World Wide Web (http://hydra.mpae.gwdg.de/mpae_projects/SUMER/sumer.html) or by contacting one of the authors. Title: Intercalibration and Co-Registration of the LASCO, UVCS and SUMER instruments on SOHO Authors: Michels, J.; Kohl, J. L.; Noci, G.; Antonucci, E.; Tondello, G.; Huber, M. C. E.; Curdt, W.; Hollandt, J.; Lemaire, P.; Schuhle, U.; Wilhelm, K.; Korendyke, C.; Moran, T.; Raymond, J. C.; Romoli, M.; Benna, C.; Ciaravella, A.; Fineschi, S.; Gardner, L. D.; Giordano, S.; Naletto, G.; Nicolosi, P.; Siegmund, O. H. W.; Spadaro, D.; Smith, P. L.; Strachan, L. Bibcode: 1996AAS...188.3706M Altcode: 1996BAAS...28..878M Joint observations of equatorial streamers by three SOHO instruments have been used for radiometric intercalibration, co-registration and other spectroscopic comparisons. The results are used to track the stability of the radiometric calibrations of the Ultraviolet Coronagraph Spectrometer (UVCS) and the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) experiment at overlapping wavelenghs. Observations of equatorial streamers at heliocentric heights from 1.25 to 1.5 R_⊙ are used for the intercalibrations. The results are compared to pre-launch laboratory calibrations and to observations of stars. The first stellar observation was for 38 AQI. These UV observations are compared to coronal green line (Fe XIV) observations obtained with the Large Angle Spectrometric Coronagraph (LASCO) C1 coronagraph obtained in the same time frame. Intercomparisons of spectral line profiles among LASCO, SUMER, and UVCS are also planned. The LASCO research is supported by NASA Grant NDPR S92835D; the UVCS research is supported by NASA Contract NAS5-31250 to the Smithsonian Astrophysical Observatory, by the Italian Space Agency and by Switzerland, and SUMER is financially supported by BMFT/DARA, CNES, NASA and PRODEX (Swiss Contribution). Title: Solar Coronal Heating - Present Knowledge and Hopes from SOHO Authors: Lemaire, P. Bibcode: 1996MmSAI..67..979L Altcode: 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 104 to 2 × 106K 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 104 to 2 multiplied by 106 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-1. We report here on some specific features of this instrument related to its pointing as well as its spatial and spectral resolution capabilities. Title: Corot: a Space Project Devoted to the Study of Convection and Rotation in Stars Authors: Catala, C.; Auvergne, M.; Baglin, A.; Bonneau, F.; Magnan, A.; Vuillemin, A.; Goupil, M. J.; Michel, E.; Boumier, P.; Dzitko, H.; Gabriel, A.; Gautier, D.; Lemaire, P.; Mangeney, A.; Mosser, B.; Turck-Chiéze, S.; Zahn, J. P. Bibcode: 1995ESASP.376b.549C Altcode: 1995soho....2..549C; 1995help.confP.549C No abstract at ADS Title: High resolution profiles of the MG II H and MG II K lines. Authors: Staath, E.; Lemaire, P. Bibcode: 1995A&A...295..517S Altcode: Spectra of the Mg II h and k lines have been recorded by the balloon-borne telescope spectrograph RASOLBA. The observations have been made at the center of the solar disk and across the limb with an angular resolution of 1arcsec along the 30x0.3arcsec^2^ slit and a spectral resolution of 15pm within the 20nm wavelength range. We present here the method used to reduce the data and profiles of these lines at several locations on the solar disk with uncertainties in the intensity of 16% at sun center. Integral and spectral intensity, line of sight velocities and limb darkening curve derived from these spectra are discussed. Title: COROT: A Proposal to Study Stellar Convection and Internal Rotation Authors: Catala, C.; Mangeney, A.; Gautier, D.; Auvergne, M.; Baglin, A.; Goupil, M. J.; Michel, E.; Zahn, J. P.; Magnan, A.; Vuillemin, A.; Boumier, P.; Gabriel, A.; Lemaire, P.; Turck-Chieze, S.; Dzitko, H.; Mosser, B.; Bonneau, F. Bibcode: 1995ASPC...76..426C Altcode: 1995gong.conf..426C No abstract at ADS Title: Study of the quiet corona with the SOHO/SUMER spectrometer Authors: Lemaire, P.; Wilhelm, K. Bibcode: 1994AdSpR..14d.171L Altcode: 1994AdSpR..14..171L The SOHO/SUMER spectrometer is developed to study the low corona and chromosphere-corona transition zone. The main scientific objectives are oriented towards the search of mechanisms producing the coronal heating and driving the first impulse of the solar wind. The main contribution will be given by an accurate measurement of line profiles, intensities and shifts combined with high angular resolution on the solar disk and above the limb. In this paper, we recall the scientific objectives, we describe the corresponding instrument capabilities and we show how the observations can be performed and the kind of data expected. The complementary role of the SOHO coronal instruments in coordinating observations to optimize the quality of the data is emphasized. Title: Center-to-limb observations of the lambda 285.2 NM MgI UV resonance line Authors: Briand, C.; Lemaire, P. Bibcode: 1994A&A...282..621B Altcode: We present here new results about the 285.212 nm Mg I resonance line. The spectra have been obtained from the RASOLBA balloon experiment of the LPSP launched in 1986 from France. The data have both high spectral (1.5 pm) and spatial (1 sec) resolution. Spectra of either the Sun center and the solar limb have been recorded in the 280 nm range. We paid a careful attention on the spatial evolution of the Mg I absorption line with the hope to find predicted but not confirmed emission feature in the central core. The very faint emission detected at Sun center becomes bright when observed off-limb. We give some measurements of the Mg I core Doppler shifts. 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: Space instrumentation Authors: Lemaire, P. Bibcode: 1994LNP...432..297L Altcode: 1994LNPM...11..297L The capabilities of space instrumentation are in a continuous state of evolution with the improvement of new techniques such as the metallic multilayer coatings in the Extreme UltraViolet. After a brief review of a few of the new techniques that will provide improved detectors, a survey of current instrumentation is given (Yohkoh, HRTS, MSSA, NIXT). Several missions are in preparation (SOHO, CORONAS); a description of the payload capabilities of these is furnished. Finally, we speculate on the outlook for the new, improved instruments on future missions. Title: High Resolution Mg II h and Mg II k Line Profiles Authors: Staath, E.; Lemaire, P. Bibcode: 1994emsp.conf..107S Altcode: No abstract at ADS Title: Mg I UV and IR Lines of the Quiet Sun Authors: Briand, C.; Lemaire, P. Bibcode: 1994emsp.conf...53B Altcode: No abstract at ADS Title: PRISMA: A mission to study interior and surface of stars Authors: Lemaire, P. Bibcode: 1994esa..conf..540L Altcode: 1994IAUCo.147..540L No abstract at ADS 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: Prospects for improved instrumentation on future solar space missions. Authors: Lemaire, P. Bibcode: 1993ESASP1157...67L Altcode: 1993srfs.book...67L After a brief summary of the status of space-based instrumentation at the time when Soho is launched, the areas where improvements are foreseeable are examined and an overview of the gains that can be achieved is presented. Special attention is paid to identifying intrinsic limitations related to classical mountings in the ultraviolet (UV)/extreme-ultraviolet (EUV) range. Some mountings are then discussed, with their limitations, in the context of missions already proposed. Title: High Resolution Measurements of the 273-293 nm Solar Spectrum from a Balloon Instrumentation Authors: Lemaire, P.; Briand, C.; Staath, E.; Samain, D. Bibcode: 1993BAAS...25.1221L Altcode: No abstract at ADS Title: Une proposition pour le sondage de l'interieur des étoiles et l'étude de la génération de l'activité (PRISMA). Authors: Lemaire, P.; Catala, C. Bibcode: 1993JAF....44...35L Altcode: No abstract at ADS Title: Prisma - the First Space Mission to See Inside the Stars Authors: Appourchaux, T.; Gough, D. O.; Catala, C.; Frandsen, S.; Frohlich, C.; Hoyng, P.; Jones, A.; Lemaire, P.; Tondello, G.; Weiss, W. W. Bibcode: 1993ASPC...42..411A Altcode: 1993gong.conf..411A No abstract at ADS Title: SOHO: a PRISMA precursor Authors: Lemaire, P. Bibcode: 1993ASPC...40..755L Altcode: 1993ist..proc..755L; 1993IAUCo.137..755L No abstract at ADS Title: Stellar seismology and activity: the need to go to space (PRISMA) (invited paper) Authors: Appourchaux, T.; Catala, C.; Catalano, S.; Frandsen, S.; Jones, A.; Lemaire, P.; Weiss, W. W. Bibcode: 1993MmSAI..64..415A Altcode: No abstract at ADS Title: PRISMA: Probing Stars from Core to Corona Authors: Appourchaux, T.; Catala, C.; Catalano, S.; Fransden, S.; Fröhlich, C.; Gough, D. O.; Hoyng, P.; Jones, A.; Lemaire, P.; Tondello, G.; Weiss, W. Bibcode: 1993ASSL..183..505A Altcode: 1993pssc.symp..505A No abstract at ADS Title: PRISMA: a new space mission for stellar physics. Authors: Appourchaux, T.; Gough, D.; Hyoyng, P.; Catala, C.; Frandsen, S.; Froehlich, C.; Jones, A.; Lemaire, P.; Tondello, G.; Weiss, W. W. Bibcode: 1993ASPC...40..812A Altcode: 1993ist..proc..812A; 1993IAUCo.137..812A This paper mainly focuses on the scientific objectives that can be achieved with a new space mission of the European Space Agency - PRISMA (Probing Rotation and Interior of Stars: Microvariability and Activity). The scientific objectives can be classified into three areas of interest: (1) Stellar structure and evolution. (2) Stellar atmospheres and magnetic fields. (3) Stellar dynamics and stellar dynamos. 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 104 and a few 106K. 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: "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 104 to more than 1.8×106K. Title: Planned observations at high resolution from space. Authors: Lemaire, P.; Marsch, E. Bibcode: 1992ESASP.344...15L Altcode: 1992spai.rept...15L The next generation of solar space experiments is under development. SOHO with its set of coronal instruments has some capability to improve the angular resolution already obtained in the far UV to the extreme UV, corresponding to the temperature range between 10 and a few 10K. The authors give some insights into the two spectrometers SUMER and CDS, and the extreme UV imager EIT. SUMER is developed to study the dynamics of the low corona and the chromosphere-corona transition zone in using the 50 - 160 nm wavelength range. CDS is a spectrometer built to observe the highest part of the chromosphere-corona transition zone up to the high corona of several millions of degrees in using the 15 - 80 nm wavelength range. EIT is a multi-wavelength imager that will provide either full or partial solar images in upper chromospheric and coronal lines. 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: PRISMA: A Space Facility for Studying the Rotation; Interior of Stars Authors: Lemaire, P.; Appourchaux, T.; Jones, A.; Catala, C.; Catalano, S.; Frandsen, S.; Weiss, W. Bibcode: 1992ASPC...26..643L Altcode: 1992csss....7..643L No abstract at ADS Title: Ultraviolet conical diffraction: a near-stigmatic tandem grating mounting spectrometer Authors: Lemaire, Philippe Bibcode: 1991ApOpt..30.1294L Altcode: A tandem conical diffraction mount for UV and EUV operation is proposed which improves spectral resolution and virtually eliminates monochromatic slit-image rotation, thereby improving spectral image quality. Attention is given to the illustrative example of a complete solar telescope-spectrometer instrumentation; a comparison is made of the spectral and angular resolution qualities and lower-efficiency limits of the mountings with other, recently developed solar instrumentations for the 30-135 nm bandpass. As expected, however, the equivalent efficiency of the present instrument is lower than that of the alternatives with which it is compared. 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: Prisma - a Space Facility for Studying Rotation and Activity Authors: Lemaire, P.; Appourchaux, T.; Catala, C.; Catalano, S.; Frandsen, S.; Jones, A.; Weiss, W. Bibcode: 1991ASIC..340..397L Altcode: 1991amey.conf..397L No abstract at ADS Title: ESO observations with the IAP/IAS Ca II K special spectrometer during the MUSICOS 89 campaign. Authors: Char, S.; Foing, B.; Lemaire, P.; Lagrange, A. M.; Beust, H.; Vidal Madjar, A.; Vitry, R.; Zimmerman, J. P. Bibcode: 1991musi.work...69C Altcode: HR 1099, a highly active RS CVn star was monitored in the chromospheric Ca II K line during the Musicos campaign. The authors used a special spectrometer developed to monitoring variations of the Ca II lines on stars (circumstellar absorption for β Pictoris and emissive features on stars showing solar-like magnetic activity such as the RS CVn and late type stars). They describe the characteristics of the instrument and show a sample of obtained spectra for HR 1099. Title: SOHO-A high resolution solar physics mission Authors: Lemaire, P. Bibcode: 1991AdSpR..11e.169L Altcode: 1991AdSpR..11..169L SOHO (SOlar and Heliospheric Observatory) is a joint ESA/NASA mission within the ISTP-International Solar Terrestrial Program. The satellite, with a pointing stability of 1 arcsecond, will be launched in 1995 to the L1 Lagrangian point between Sun and Earth. The selected payload, in accordance with the scientific objectives of the mission, is being developed:

-to obtain long and uninterrupted series of solar oscillations measurements either in flux or in velocity in order to sound the solar interior using high resolution in the frequency domain.

-to probe the upper solar atmosphere with high resolution UV/EUV imager/spectrometers and UV/visible coronagraphs and photometers in order to bring new constraints on the coronal heating, to identify the source and accelerating mechanisms of the solar wind.

-to measure in-situ the solar wind flow in front of the Earth and so, establish the link between the Sun and the near-Earth environment. Title: Sensitivity changes in the CNRS ultraviolet spectrometer aboard OSO-8. Authors: Lemaire, P. Bibcode: 1991ESAJ...15..237L Altcode: The CNRS solar ultraviolet multichannel experiment on the OSO-8 spacecraft operated from Jun 1975 to Sep 1978. At the beginning of orbital operations, a strong sensitivity change appeared in the ultraviolet channels. After a brief description of the instrumentation, the main optical parameters and the principle of the experiment, and the integration procedures and preflight calibration control, the in-orbit measurements of sensitivity are presented and the results are critically discussed. Title: Possible observations of coronal heating and solar/stellar winds with space instruments. Authors: Lemaire, P. Bibcode: 1991cwlt.conf...33L Altcode: The need for new observations of solar/stellar coronae and winds is clearly established and requires dedicated instrumentation in coordinated missions. The objectives and the expected performance of the SOHO coronal payload are described on one hand. On the other hand, some insight into the stellar PRISMA mission in study at ESA are given. Title: Prisma-probing rotation and interior of stars: Microvariability and activity Authors: Lemaire, P.; Appourchaux, T.; Catala, C.; Catalano, S.; Frandsen, S.; Jones, A.; Weiss, W. Bibcode: 1991AdSpR..11d.141L Altcode: 1991AdSpR..11..141L The measurement of frequencies, amplitudes and lifetimes of solar oscillations has proven to be a very powerful tool to sound the properties of the solar internal structure. Combined with observations of emerging solar magnetic field parameters of the solar internal structure and dynamo can be inferred. The same techniques may be used to sound stellar interiors: asteroseismology and observation of magnetic activity (emerging magnetic fields). The observation of photometric fluctuations down to micromagnitudes on stars along or near the main sequence when complemented with measurements of activity levels will provide a wealth of information on the internal structure and rotation rates, and its evolutions with age. The PRISMA mission is an ESA Assessment Study currently underway. We present here the scientific objectives of the mission, the measurements to be made, the techniques to be used, and the main characteristics of a model payload. Title: The imaging fourier transform spectrometer for the SIMURIS mission Authors: Foing, B. H.; Dame, L.; Thorne, A. P.; Lemaire, P. Bibcode: 1991AdSpR..11a.387F Altcode: 1991AdSpR..11..387F The Solar Interferometric Mission for Ultrahigh Resolution Imaging and Spectroscopy (SIMURIS) is an interferometric investigation in space at ultraviolet and visible wavelengths aimed at reconnaissance of solar features at angular scales from 0.3 to 0.01 arcsec. The Imaging Fourier Transform Spectrometer (IFTS) is, with the Solar Ultraviolet Network (SUN), one of the core instruments of the proposed SIMURIS mission. It consists of a 40 cm Gregory telescope feeding a double grating pre-dispersive spectrometer before entering a Fourier transform spectrometer for a field of 10 × 10 arcsec2 at 0.3 arcsec resolution. The SIMURIS/IFTS requires upgrading of existing FTS down to 120 nm, with imaging capabilities. For the IFTS imaging a detector with fast readout must be used. There are also demanding constraints on the real time processing, and the subsequent important data rate, and requirements on an upgraded instrument pointing system (IPS), within the resources and capabilities of the Space Station. Title: Experimental study of the role of plasma polarization on line shape in dense laboratory plasmas. Authors: Jamelot, G.; Jaegle, P.; Lemaire, P.; Carillon, A. Bibcode: 1990JQSRT..44...71J Altcode: This paper presents an experimental study of the spectral line profiles emitted by multicharged ions in dense laser-produced plasmas. The time and/or space integrated spectra of the Lyman series of H-like lithium show a strong red asymmetry and, in some cases, a red shift of the top of the lines. It is shown that such profiles have to be interpreted as due to space and time integration of mostly symmetric profiles, which are red shifted by an amount that depends on the emitting plasma zone. Theoretically calculated profiles show the role, in the observed profiles, of the plasma polarization shift due to the penetration of atomic orbits by the plasma free electrons. 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.

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: 8-25 eV high resolution solar spectrometer Authors: Lemaire, Philippe; Wilhelm, Klaus Bibcode: 1989SPIE.1140..522L Altcode: No abstract at ADS Title: Solar Ultraviolet Network: an interferometric investigation of the fundamental solar astrophysical scales Authors: Dame, Luc; Moreau, Bernard G.; Cornwell, Timothy J.; Visser, H.; Title, Alan M.; Acton, Loren W.; Aime, Claude; Braam, Bart M.; Bruner, Marilyn E.; Connes, Pierre; Faucherre, Michel; Foing, B. H.; Haisch, Bernhard M.; Hoekstra, Roel; Heyvaerts, Jean; Jalin, Rene; Lemaire, Philippe; Martic, Milena; Muller, R.; Noens, J. C.; Porteneuve, Jacques; Schulz-Luepertz, E.; von der Luehe, Oskar Bibcode: 1989SPIE.1130..126D Altcode: The Solar UV Network (SUN) presently proposed is an interferometric system, based on the principles of stabilized interferometry, which will be capable of solar observations with spatial resolutions better than 0.013 arcsec. SUN will consist of four 20-cm diameter telescopes aligned nonredundantly on a 2-m baseline. SUN is judged to be ideally deployable by the NASA Space Station, if implemented on a pointing platform whose performance is of the order of the Instrument Pointing System flown on Spacelab 2. The compact, nonredundant configuration of SUN's telescopes will allow high-resolution imaging of a 2 x 2 arcsec field on the solar disk. Title: High resolution observations of the solar UV spectrum from balloon Authors: Lemaire, P.; Samain, D. Bibcode: 1989hsrs.conf..551L Altcode: No abstract at ADS Title: Use of thinned backside illuminated CCD from the extreme ultraviolet to the soft ultraviolet Authors: Hochedez, Jean-Francois E.; Lemaire, Philippe; Delaboudiniere, Jean-Pierre; Cougrand, Bernard; Barba, Julien Bibcode: 1989SPIE.1070...53H 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: 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: 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, M. C. E.; Lemaire, P.; Marsch, E.; Poland, A. I. Bibcode: 1988sohi.rept...31W 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 ultra violet) 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: Needs for high resolution spectroscopy in ultraviolet solar physics. Authors: Lemaire, P. Bibcode: 1988JPhys..49..335L Altcode: 1988IAUCo.102..335L The study of the solar atmosphere (from 5000K to few millions K) is made through ultraviolet lines emitted by ionized elements. The understanding of the heating processes, the solar wind generation and its acceleration mechanisms require a global and detailed mass and energy budget of the atmosphere. The new ultraviolet spectrometers proposed on SOHO satellite are able to combine enough angular, spectral and temporal resolutions to establish this budget. Title: Prospect for Stellar Seismology on Board an Interplanetary Spacecraft Authors: Praderie, F.; Mangeney, A.; Lemaire, P.; Puget, P.; Bisnovatyi-Kogan, G. S. Bibcode: 1988IAUS..123..549P Altcode: The authors describe a stellar seismology photometric experiment which they have proposed to embark on-board the interplanetary vehicles belonging to the VESTA mission (France-USSR mission towards Mars and the asteroids belt, to be launched about 1994). The objective is to use the cruise time to obtain long, uninterrupted observations of the white light fluctuations in a few late-type stars, with a view to the detection of global non-radial modes at the level 10-5 to 10-6mag. Title: Solar Ultraviolet Spectrum Obtained from a Balloon Gondola Authors: Samain, D.; Lemaire, P. Bibcode: 1987ESASP.270..347S Altcode: 1987erbp.symp..347S A new flight of the L.P.S.P. balloon experiment on September 19, 1986 has permitted the recording of high resolution photographic spectra in the 2800 Å channel (1 arcsec and 15 mÅ). Several time sequences at Sun center, limb, intermediate location (μ = 0.5) and on a prominence have been performed; some of these results are presented. Data reduction of the high spectral resolution spectra recorded in 1982 has been completed for the region 1950-2000 Å, in which many features have been measured and tabulated; one of these detailed tracings is given and some results on wavelength shifts analysed. Title: "Underluminous" Lyman-alpha Emission Associated with Active-Region Magnetic Canopy Authors: Jones, H. P.; Skumanich, A.; Lemaire, P. Bibcode: 1987BAAS...19..930J Altcode: No abstract at ADS Title: Physical structure and diagnostics of solar active regions deduced from optical, visible and UV observations. Authors: Lemaire, P. Bibcode: 1987PAICz..66..185L Altcode: 1987eram....1..185L This paper reviews the status of our knowledge of the physical properties of active regions in the photosphere, chromosphere and transition zone, as inferred from observations. Title: Analysis of solar and stellar chromospheric calcium and magnesium lines Authors: Lemaire, P.; Simon, G.; Mangeney, A.; Clary, O.; Praderie, F.; Mouradian, Z. Bibcode: 1986AdSpR...6h..73L Altcode: 1986AdSpR...6R..73L Using a combination of ground-based and satellite observations of the Sun, we determine several parameters of CaII H, K and MgII h, k chromospheric lines. From simple chromospheric models (similar to those proposed by T. Ayres) we establish semi-empirical laws obeyed by some of these parameters. This allows us to deduce some constraints on the chromospheric heating rate. These results are then applied to observed spectra of main sequence stars. Title: Balloon-Borne Ultraviolet Solar Telescope and High Resolution Echelle Spectrograph - Instrumentation and First Results Authors: Samain, D.; Lemaire, P. Bibcode: 1985Ap&SS.115..227S Altcode: A description of the LPSP balloon-borne telescope — spectrograph combination is given. The payload comprises a one-axis stabilized platform carrying a two-axes equatorial pointing system; the instrumentation directed towards the Sun is a 300 mm telescope coupled with an echelle spectrograph and a slit jaw camera. The scientific objective of the experimental set-up is to observe spatial, spectral, and temporal variations of fine structures of the solar atmosphere, using ballon ultraviolet windows between 190 and 300 nm, with very high angular and spectral resolutions (0.5 arc sec and 1 pm). In the configuration of the first flight which successfully took place on 1 October, 1982 from Aire-sur'l'Adour (Landes), many stigmatic spectra of the Sun were recorded in the 190 213 and 272 293 nm ranges, with an angular resolution of 4 arc sec and a spectral resolution of 1.5 to 2 pm. Title: Solar High Resolution Balloon Spectra Obtained in the 190-300 nm Wavelength Band Authors: Samain, D.; Lemaire, P. Bibcode: 1985LNP...233..123S Altcode: 1985hrsp.proc..123S A balloon gondola with a solar telescope spectrograph has been launched from Aire/Adour (France) October 1, 1982. High quality spectra with a spectral resolution better than 1.5 pm and with a 4 - 5 arcseconds angular resolution have been recorded in the atmospheric window domains: 195 - 212 nm and 272 - 292 nm. Results from this first flight are discussed. Title: Solar Physics from Space Authors: Lemaire, P. Bibcode: 1985ESASP.229..139L Altcode: 1985erbp.symp..139L During the last years, as a result of a continuous effort, new insights have been given on the physics of solar phenomena. Observational data coming from satellites, rockets and balloon experiments have been combined with ground based observations and have stimulated new theoretical explanations. During the same period, global characteristics of the sun (such as activity and magnetic fields, corona and solar winds, oscillations) have been recognized as a feature of stars during a period of their evolution. Unsatisfactory detailed mechanisms to explain these characteristics are under study and to select and improve theory new types of observations are required. Title: Solar high resolution balloon spectra obtained in the 190-300 nm wavelength band Authors: Lemaire, P.; Samain, D. Bibcode: 1984AdSpR...4h..37L Altcode: 1984AdSpR...4...37L To obtain solar high-resolution balloon spectra in the 190-300 nm wavelength range outside of the strong absorption ozone band, a new solar instrumentation and an equatorial mounting platform are developed. The instrumentation, which consists of a telescope-spectrograph combination, and its characteristics are described. Observations are made at an altitude of 38 km and two sequences of spectra are taken near sun center, one on a supergranular cell and the other one over an active network. The spectra recorded during the flight show an intensity variation related to the wavelength dependance of atmospheric transmission. The results obtained in two wavelength domains (190-210 nm and 272-283 nm) during the first balloon flight are presented and discussed. The spectral resolution is found to be better than 2 pm in the 200 nm range and better than 1.5 pm in the 280 nm range; and the angular resolution is found to be about 5 arcsec. Calibration in intensity is made by comparison to rocket spectra. Stigmatic line profiles illustrate the results. Title: A Stabilized Platform Carrying One or Two Telescopes Authors: Lemaire, P. Bibcode: 1984srps.conf..177L Altcode: The study of a mission dedicated to stellar variability and activity leads to two specific instrumentations: a white light photometer and an ultraviolet multichannel spectrometer. Although it is possible to combine the two objectives in one instrumentation, for the optimization of the mission two separate instruments will give the best scientific return. The optical schemes presented here are not intended to provide the ultimate design; but they give the sensitivity and resolution expected from classical instrumentation and are useful to define a preliminary mission. 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 × 1013 cm-3 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: Increasing solar chromosphere line intensities with solar activity Authors: Lemaire, P. Bibcode: 1984AdSpR...4h..29L Altcode: 1984AdSpR...4...29L Solar activity is characterized either by sunspots or by plages. Sunspots are detected in the continuum visible as dark features. Plages are defined in chromospheric lines such as CaII H and K or HI H-alpha by brightness enhancements. Chromospheric activity is an important parameter for the knowledge of the equilibrium input and output energy of the outer solar atmosphere. The OSO-8/L.P.S.P.-multichannel experiment has recorded simultaneous chromospheric profiles in H and K CaII, h and k MgII, L-alpha and L-beta HI lines. Those lines are formed from the temperature minimum (4200 K) to the higher part of the chromosphere (30000 K). A data set recorded over a quiet sun, plage, penumbra, and filament is presented hereafter. The observations, data reduction, and calibration are described. Then a comparison between line intensities is made and results are discussed. Title: On the PSIVA approach to stellar seismology and activity from space Authors: Praderie, F.; Mangeney, A.; Lemaire, P. Bibcode: 1984AdSpR...4h.163P Altcode: 1984AdSpR...4..163P We propose a modest payload, using a simple telescope and well known technology, with the aim of placing the probing of stellar interiors on an experimental basis. Indeed, a number of physical processes, the seat of which is in stellar interiors and which are of basic importance for physics and astrophysics, have not yet been mastered : convection, differential rotation, dynamo generation of magnetic fields, etc...Collecting significant observations is of prime importance to elucidate those phenomena.

Two types of observations are sought :

-The pulsation spectrum (detection of microvariability at the level of that found in the Sun, i.e. 10-6 mag).

-The active phenomena of magnetic origin in the atmosphere, at various altitudes simultaneously, for a representative sample of stars over the Hertzsprung-Russell diagram.

The basic requirements are long series of continuous and homogeneous observations with high photometric accuracy

-in white light

-in four spectroscopic indices, three of them being in the UV range (CaII λ 3933 A, MgII λ 2800 A, HeII λ 1640 A, CIV λ 1550 A).

The motives to perform these observations from space will be analyzed. Title: H and K Ca II plage profiles obtained with a Fourier Transform Spectrometer Authors: Lemaire, P. Bibcode: 1983SoPh...88...31L Altcode: H and K Ca II plage profiles have been obtained with the Kitt Peak Fourier Transform Spectrometer. A good correlation exists between the K1 minimum separation and the K index. Correlation between CN band index and magnetic field is also evidenced, but, probably due to the poor statistic, no clear correlation appears between K index and magnetic field. Title: Magnesium II line formation - The contribution of high atomic levels to the resonance lines Authors: Lemaire, P.; Gouttebroze, P. Bibcode: 1983A&A...125..241L Altcode: An evaluation of the solar and stellar atmospheric modeling consequences of the use of different Mg(+) ion atomic models in line profile computations has determined that the h and k line cores appear to be almost insensitive to the number of levels used in the profile computations. A careful treatment of the blended resonance doublet wings appears to be necessary, however, for atmospheric diagnostics using the subordinate 279.1 and 179.9 lines. The cores and near wings of h and k are strongly sensitive to the atmospheric model, from the higher part of the photosphere to the upper part of the chromospheric plateau. Title: A high-resolution ultraviolet solar telescope/spectrograph mounted on an equatorial balloon platform Authors: Samain, D.; Lemaire, P. Bibcode: 1983ESASP.183..401S Altcode: A balloon-borne 30 cm telescope-spectrograph combination was built to observe fine structures of the solar atmosphere with very high spectral and angular resolution in two atmospheric windows: 2700 to 2950 A and 1900 to 2300 A. Solar spectra with spectral resolution of 15 mA and angular resolution of 4 arcsec were recorded. Title: L'utilisation des ballons stratosphériques en astronomie: la réalisation de nacelles pointées sur le soleil pour l'étude du spectre ultraviolet solaire. Authors: Lemaire, P. Bibcode: 1983LAstr..97..211L Altcode: The design and performance characteristics of sun-pointing nacelles for high altitude balloon observation of solar emissions is described. Solar UV astronomy at altitudes above 30 km allows detection of spectral lines below 3000 A otherwise absorbed by the atmosphere, particularly by ozone. The resonance doublet of Mg is observable, providing information on the mean chromospheric behavior. Emissions below 2080 A are accessible, and originate in the thin atmospheric layer around the sun. An equatorial nacelle allows the sun-pointing fixation of the instruments. Meridional acquisition is achieved by means of a magnetometer and a reaction wheel, which decouples the nacelle from motions of the tether connecting the nacelle to the balloon. Narrow-field sun sensors with successively higher resolution within a series produce stabilization on the solar disk. The first flight of the nacelle was in 1982, when a pointing accuracy of 4 deg was demonstrated while using a spectrograph. 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: 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 × 1010 cm-3 ≲ne* ≲2.3 × 1011 cm-3 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: Haute résolution U.V. solaire OSO8 - LPSP Authors: Lemaire, P. Bibcode: 1981hrse.conf..197L Altcode: No abstract at ADS Title: Haute résolution U.V. solaire HRTS - NRL Authors: Lemaire, P. Bibcode: 1981hrse.conf..195L 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: 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: Solar optical telescope (SOT). Authors: Dunn, R. B.; Fisher, R.; Harvey, J.; Lemaire, P.; Milkey, R.; Smithson, R.; Beckers, J.; Mehltretter, J. P.; Zirin, H. Bibcode: 1979MmArc.106..135D Altcode: No abstract at ADS Title: Science opportunities with the SOT. Authors: Dunn, R. B.; Fisher, R.; Harvey, J.; Lemaire, P.; Milkey, R.; Smithson, R.; Beckers, J.; Mehltretter, J. P.; Zirin, H. Bibcode: 1979MmArc.106..245D Altcode: 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: Development of a High Resolution Ultraviolet Solar Spectrograph to BE Launched on a Balloon Equatorial Platform Authors: Lemaire, P.; Samain, D. Bibcode: 1978ESASP.135..283L Altcode: 1978esrb.rept..283L A telescope-spectrometer instrumentation to study the sun in the spectral ranges 1950-2200 A and 2650-2900 A is being developed to obtain spatial, spectral, and time information on quiet and active fine structures of the solar photosphere-chromosphere zone. To achieve these objectives, an instrumentation able to give 0.5 arcsec angular resolution on the solar surface and 0.01 A spectral resolution was studied. 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: Solar OVI Profiles as Observed by the French Experiment Aboard OSO-8 Authors: Lemaire, P.; Artzner, G.; Bonnet, R. M.; Vial, F. C.; Skumanich, A.; Leibacher, J.; Vidal-Madjar, A. Bibcode: 1976BAAS....8R.331L Altcode: No abstract at ADS Title: Evolution of sunspot and active region morphology as observed on the resonance lines of Ca+ (K, H), Mg+ (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+ H and K, Mg+ 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: A center-to-limb analysis of solar Mg II lines. Authors: Gouttebroze, P.; Lemaire, P. Bibcode: 1974A&A....34..375G Altcode: Center-to-limb variations of Mg II resonance line profiles, deduced from balloon spectra of the sun, are studied. Limb-darkening in the line wings agrees satisfactorily with frequency-indpendent source functions and Voigt profiles for line absorption coefficients. Estimates of Doppler widths from a line core analysis show a rapid increase of turbulence velocities with height. The source functions of the two lines are found to be unequal at the same geometrical depth, which suggests that collisional coupling between fine-structure levels (3p) is weak. Apparent source function variations with frequency are found in the spectral interval from 0.2 to 0.5 A from line center. Several possible explanations of this fact (partially conherent scattering, geometrical and dynamical effects) are discussed. Title: Magnesium II Doublet Profiles of Chromospheric Inhomogeneities at the Center of The Solar Disk Authors: Lemaire, P.; Skumanich, A. Bibcode: 1973BAAS....5R.275L Altcode: No abstract at ADS Title: Magnesium II Doublet Profiles of Chromospheric Inhomogeneities at the Center of the Solar Disk Authors: Lemaire, P.; Skumanich, A. Bibcode: 1973A&A....22...61L Altcode: Summary. An analysis of a balloon spectrum of the sun obtained on June 24 1970, with 7" angnlar resolution and 25 mA spectral resolution respectively is presented. Average cell, network and plages profiles near the center of the solar disk are identified and compared with profiles computed on the basis of recent chromospheric models. Key words: sun - spectrum - ultraviolet chromosphere Title: High Resolution Balloon-Borne Spectrograph for the Near Solar Ultraviolet Authors: Lemaire, P. Bibcode: 1971IAUS...41..263L Altcode: No abstract at ADS Title: Resonance Lines in the Solar Chromosphere Authors: Lemaire, P. Bibcode: 1970IAUS...36..250L Altcode: No abstract at ADS Title: High Resolution Balloon Spectra of the Sun in the Mg II Doublet Lines II Authors: Lemaire, P. Bibcode: 1969ApL.....3...43L Altcode: No abstract at ADS Title: Stigmatic Balloon Spectra of the Solar MG II Doublet Authors: Lemaire, P.; Blamont, J. E. Bibcode: 1967ApJ...150L.129L Altcode: No abstract at ADS