J. N. Bahcall and M. H. Pinsonneault, Helium diffusion in the sun, The Astrophysical Journal, vol.395, issue.2, pp.119-122, 1992.
DOI : 10.1086/186502

B. L. Barraclough, J. T. Gosling, D. J. Mccomas, and B. E. Goldstein, Helium abundance variations in the solar wind: Observations from ULYSSES, Proc. of the International Solar Wind 8 Conference, p.73, 1995.

S. Basu and H. M. Antia, Helium Abundance in the Solar Envelope, Mont. Not. Roy. Astron. Soc, vol.276, pp.1402-1408, 1995.

S. Basu, Effects of errors in the solar radius on helioseismic inferences, Monthly Notices of the Royal Astronomical Society, vol.298, issue.3, pp.719-728, 1998.
DOI : 10.1046/j.1365-8711.1998.01690.x

R. M. Broussard, N. R. Sheeley, R. Tousey, and J. H. Underwood, A survey of coronal holes and their solar wind associations throughout sunspot cycle 20, Solar Physics, vol.15, issue.1, pp.161-183, 1978.
DOI : 10.1007/BF00152641

A. Bürgi and J. Geiss, Helium and minor ions in the corona and solar wind: Dynamics and charge states, Solar Physics, vol.29, issue.2, pp.347-383, 1986.
DOI : 10.1007/BF00147835

J. Christensen-dalsgaard, C. R. Priffitt, and M. J. Thompson, Effects of diffusion on solar models and their oscillation frequencies, The Astrophysical Journal, vol.403, issue.2, pp.75-78, 1993.
DOI : 10.1086/186725

J. Delaboudinì-ere, Resonance Scattering of 30.4 nm Chromospheric Radiation by Coronal Singly ionized Helium Observed with EIT, Solar Physics, vol.188, issue.2, pp.259-275, 1999.
DOI : 10.1023/A:1005268807716

A. H. Gabriel, Measurements on the Lyman alpha corona, Solar Physics, vol.136, issue.2, pp.393-400, 1971.
DOI : 10.1007/BF00154290

S. R. Habbal and R. Esser, On the derivation of empirical limits on the helium abundance in coronal holes below 1.5 solar radius, The Astrophysical Journal, vol.421, pp.59-62, 1994.
DOI : 10.1086/187187

V. H. Hansteen and E. Leer, Coupling of the Coronal Helium Abundance to the Solar Wind Astrophys, Journ, vol.428, pp.843-853, 1994.

V. H. Hansteen, E. Leer, and T. Holzer, The Role of Helium in the Outer Solar Atmosphere, The Astrophysical Journal, vol.482, issue.1, pp.498-509
DOI : 10.1086/304111

J. Joselyn and T. E. Holzer, A steady three-fluid coronal expansion for nonspherical geometries, Journal of Geophysical Research, vol.18, issue.A3, pp.1019-1026, 1978.
DOI : 10.1029/JA083iA03p01019

J. M. Laming and U. Feldman, The solar abundance of helium determined from a redshifted plasma flow over a sunspot, The Astrophysical Journal, vol.426, pp.414-424, 1994.
DOI : 10.1086/174077

J. M. Laming and U. Feldman, Measuring the Solar Helium Abundance in the Outer Corona with Sumer Plasma Dynamics ans Diagnostics in the Solar Transition Region and Corona, Proc. 8 t h SOHO Workshop, pp.405-410, 1999.

J. E. Mazur and G. M. Mason, The abundances of hydrogen, helium, oxygen, and iron accelerated in large solar particle events, The Astrophysical Journal, vol.404, pp.810-817, 1993.
DOI : 10.1086/172336

J. Meyer, The baseline composition of solar energetic particles, The Astrophysical Journal Supplement Series, vol.57, pp.151-171, 1985.
DOI : 10.1086/191000

K. A. Olive, G. Steigman, and T. P. Walker, The upper bound to the primordial abundance of helium and the consistency of the hot big bang model, The Astrophysical Journal, vol.380, pp.1-4, 1991.
DOI : 10.1086/186159

J. H. Parkinson and A. H. Gabriel, Chase observations from spacelab 2 ??? the chase team, Advances in Space Research, vol.6, issue.8, pp.243-251, 1985.
DOI : 10.1016/0273-1177(86)90446-1

B. E. Patchett, K. Norman, A. H. Gabriel, and J. L. Culhane, The Coronal Helium Abundance Experiment on Spacelab 2, Space Science Reviews, vol.29, issue.4, pp.431-437, 1981.
DOI : 10.1007/BF00239488

O. Richard, W. A. Dziembowski, R. Sienkiewicz, and R. Goode, On the Accuracy of Helioseismic Determination of Solar Helium Abundance, Astron. Astrophys, vol.338, pp.756-760, 1998.

F. Auchère, C. E. Deforest, and G. Artzner, In-Flight Determination of the Plate Scale of the Extreme-Ultraviolet Imaging Telescope, The Astrophysical Journal, vol.529, issue.2, pp.115-117, 2000.
DOI : 10.1086/312471

F. Auchère, D. M. Hassler, D. C. Slater, and T. N. Woods, SwRI/LASP sounding rocket inter-calibration with the EIT instrument on board SOHO, 2000.

J. Defise, F. Clette, and F. Auchère, In-flight characterization and compensation of the optical properties of the EIT instrument, EUV, X-Ray and Gamma-Ray Instrumentation for Astronomy, pp.341-350, 1999.

J. R. Kuhn, H. Lin, and D. Loranz, Gain calibrating nonuniform image-array data using only the image data, Publications of the Astronomical Society of the Pacific, vol.103, pp.1097-1108, 1991.
DOI : 10.1086/132932

L. B. Lucy, An iterative technique for the rectification of observed distributions, The Astronomical Journal, vol.79, issue.6, pp.745-753, 1974.
DOI : 10.1086/111605

W. H. Richardson, Bayesian-Based Iterative Method of Image Restoration*, Journal of the Optical Society of America, vol.62, issue.1, pp.55-59, 1972.
DOI : 10.1364/JOSA.62.000055

J. Wulser, H. S. Hudson, M. Nishio, T. Kosugi, S. Masuda et al., Precise Determination of the Coordinate Systems for the YOHKOH Telescopes and the Application of a Transit of Mercury, Solar Physics, vol.180, issue.1/2, pp.131-156, 1996.
DOI : 10.1023/A:1005058818887

M. Arnaud and R. Rothenflug, An updated evaluation of recombination and ionization rates, Astron. Astrophys. Suppl. Ser, vol.60, pp.425-457, 1985.

M. Arnaud and J. Raymond, Iron ionization and recombination rates and ionization equilibrium, The Astrophysical Journal, vol.398, pp.394-406, 1992.
DOI : 10.1086/171864

C. David, A. H. Gabriel, F. Bely-dubau, A. Fludra, P. Lemaire et al., Measurement of the electron tempreature gradient in a solar coronal hole, Astron. Atrsophys. Lett, vol.336, pp.90-94, 1998.

J. Delaboudinì-ere, Resonance scattering of 30.4 nm chromospheric radiation by coronal singly ionized helium observed with EIT, Solar Physics, vol.188, issue.2, pp.259-275, 1999.
DOI : 10.1023/A:1005268807716

K. P. Dere, E. Landi, H. E. Mason, B. C. Monsignori-fossi, and P. R. Young, CHIANTI - an atomic database for emission lines, Astronomy and Astrophysics Supplement Series, vol.125, issue.1, pp.149-173, 1997.
DOI : 10.1051/aas:1997368

U. Feldman, G. A. Doschek, U. Schüle, and K. Wilhelm, Properties of quiet-sun coronal plasmas at distances of 1.03 ? R ? 1.50 along the solar equatorial plane Astrophys, Journ, vol.518, pp.500-507, 1999.

S. R. Pottasch, The Lower Solar Corona: Interpretation of the Ultraviolet Spectrum., The Astrophysical Journal, vol.137, pp.945-966, 1963.
DOI : 10.1086/147569

S. W. Anderson, J. C. Raymond, and A. Van-ballegooijen, Ultraviolet Emission-Line Intensities and Coronal Heating by Velocity Filtration: Collisionless Results, The Astrophysical Journal, vol.457, pp.939-948, 1996.
DOI : 10.1086/176787

V. Andretta, S. D. Jordan, J. W. Brosius, J. M. Davila, R. J. Thomas et al., 304 A Line in the Quiet???Sun Spectrum, The Astrophysical Journal, vol.535, issue.1, pp.438-453, 2000.
DOI : 10.1086/308833

R. G. Athay, The origin of solar He II radiation, The Astrophysical Journal, vol.329, pp.482-492, 1988.
DOI : 10.1086/166393

E. H. Avrett, J. E. Vernazza, and J. L. Linsky, Excitation and ionization of helium in the solar atmosphere, The Astrophysical Journal, vol.207, pp.199-204, 1976.
DOI : 10.1086/182212

E. H. Avrett, Combined effects of mass flows and particule diffusion on the ionization structure of the solar transition region Plasmas Dynamics and Diagnostics in the Solar Transition Region and Corona, Eigth SOHO Workshop, pp.141-144, 1999.

J. W. Brosius, J. M. Davila, and R. J. Thomas, Measuring Active and Quiet-Sun Coronal Plasma Properties with Extreme-Ultraviolet Spectra from SERTS, The Astrophysical Journal Supplement Series, vol.106, pp.143-164, 1996.
DOI : 10.1086/192332

G. E. Brueckner and J. F. Bartoe, The fine structure of the solar atmosphere in the far ultraviolet, Solar Physics, vol.33, issue.1, pp.133-156, 1974.
DOI : 10.1007/BF00161831

J. Delaboudinì-ere, Resonance Scattering of 30.4 nm Chromospheric Radiation by Coronal Singly ionized Helium Observed with EIT, Solar Physics, vol.188, issue.2, pp.259-275, 1999.
DOI : 10.1023/A:1005268807716

J. M. Fontenla, E. H. Avrett, and R. Loeser, Energy balance in the solar transition region. III - Helium emission in hydrostatic, constant-abundance models with diffusion, The Astrophysical Journal, vol.406, pp.319-345, 1993.
DOI : 10.1086/172443

A. H. Gabriel, Measurements on the Lyman alpha corona, Solar Physics, vol.136, issue.2, pp.393-400, 1971.
DOI : 10.1007/BF00154290

T. Hirayama, Spectral analysis of four quiescent prominences observed at the Peruvian eclipse, Solar Physics, vol.15, issue.1, pp.50-75, 1971.
DOI : 10.1007/BF00152861

M. C. Huber, P. V. Foukal, R. W. Noyes, E. M. Reeves, E. J. Schmahl et al., Extreme-ultraviolet observations of coronal holes - Initial results from SKYLAB, The Astrophysical Journal, vol.194, pp.115-118, 1974.
DOI : 10.1086/181682

C. Jordan, The Intensities of Helium Lines in the Solar EUV Spectrum, Monthly Notices of the Royal Astronomical Society, vol.170, issue.2, pp.429-440, 1975.
DOI : 10.1093/mnras/170.2.429

C. Jordan, Helium Line Emission: Its Relation to Atmospheric Structure, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, vol.297, issue.1433, pp.297-541, 1433.
DOI : 10.1098/rsta.1980.0230

S. D. Jordan, W. T. Thompson, R. J. Thomas, and W. M. Neupert, Solar coronal observations and formation of the He II 304 A line, The Astrophysical Journal, vol.406, pp.346-349, 1993.
DOI : 10.1086/172444

S. D. Jordan, Line formation and intensity enhancement of the HeII 304Åline304?304Åline in the solar atmosphere, IAU coloq. 144 " Solar Coronal Structures, 1994.

K. P. Macpherson and C. Jordan, The anomalous intensities of helium lines in the quiet solar transition region, Monthly Notices of the Royal Astronomical Society, vol.308, issue.2, pp.510-526, 1999.
DOI : 10.1046/j.1365-8711.1999.02744.x

R. W. Milkey, Comments concerning the photoionization model for excitation of resonance lines of He I and He II in the solar chromosphere, The Astrophysical Journal, vol.199, pp.131-132, 1975.
DOI : 10.1086/181865

J. C. Raymond, Predicted extreme-ultraviolet and X-ray spectrum of a microflare-heated corona, The Astrophysical Journal, vol.365, pp.387-390, 1990.
DOI : 10.1086/169493

J. D. Scudder, On the causes of temperature change in inhomogeneous low-density astrophysical plasmas, The Astrophysical Journal, vol.398, issue.1, pp.299-318, 1992.
DOI : 10.1086/171858

J. D. Scudder, Why all stars should possess circumstellar temperature inversions, The Astrophysical Journal, vol.398, issue.1, pp.319-349, 1992.
DOI : 10.1086/171859

R. Shine, H. Gerola, and J. L. Linsky, Diffusion effects on the line intensities of He I and He II in the solar transition region, The Astrophysical Journal, vol.202, pp.101-105, 1975.
DOI : 10.1086/181990

E. C. Shoub, Invalidity of local thermodynamic equilibrium for electrons in the solar transition region. I -Fokker-Planck results Astrophys, Journ, vol.166, pp.339-369, 1983.

R. Tousey, Some Results of Twenty Years of Extreme Ultraviolet Solar Research, The Astrophysical Journal, vol.149, issue.2, pp.239-252, 1967.
DOI : 10.1086/149249

A. F. Viñas, H. K. Wong, and A. J. Klimas, Generation of Electron Suprathermal Tails in the Upper Solar Atmosphere: Implications for Coronal Heating, The Astrophysical Journal, vol.528, issue.1, pp.509-523, 2000.
DOI : 10.1086/308151

H. Zirin, M. Arnaud, and R. Rothenflug, The helium chromosphere, coronal holes, abd stellar x-rays, Astrophys An updated evaluation of recombination and ionization rates, Journ. Astron. Astrophys, vol.199, issue.60, pp.63-66, 1975.

S. Bashkin, J. Stoner, and J. O. , Atomic Energy Levels and Grotrian Diagrams, 1. Hydrogen I -Phosphorus XV, North-Holland publishing company, 1975.

J. M. Beckers and E. Chipman, The profile and polarization of the coronal L? line, Solar Physics, vol.11, issue.1, pp.151-161, 1974.
DOI : 10.1007/BF00149606

J. W. Brosius, J. M. Davila, and R. J. Thomas, Measuring Active and Quiet-Sun Coronal Plasma Properties with Extreme-Ultraviolet Spectra from SERTS, The Astrophysical Journal Supplement Series, vol.106, pp.143-164, 1996.
DOI : 10.1086/192332

A. H. Gabriel, Measurements on the Lyman alpha corona, Solar Physics, vol.136, issue.2, pp.393-400, 1971.
DOI : 10.1007/BF00154290

L. Golub and J. M. Pasachoff, The solar corona The Edimburg building, 1997.

S. Klarsfeld, Radiative decay of metastable hydrogenic atoms, Physics Letters A, vol.30, issue.7, pp.382-383, 1969.
DOI : 10.1016/0375-9601(69)90719-1

S. Koutchmy, P. Lamy, G. Stellmacher, O. Koutchmy, N. I. Dzubenko et al., Photometrical analysis of the, Astron. Astrophys, vol.69, pp.35-42, 1973.

G. Noci, J. L. Kohl, and G. L. Withbroe, Solar wind diagnostics from Doppler-enhanced scattering, The Astrophysical Journal, vol.315, pp.315-706, 1987.
DOI : 10.1086/165172

W. K. Tobiska, Revised solar extreme ultraviolet flux model, Journal of Atmospheric and Terrestrial Physics, vol.53, issue.11-12, pp.1005-1018, 1991.
DOI : 10.1016/0021-9169(91)90046-A

W. K. Tobiska, Recent solar extreme ultraviolet irradiance observations and modeling: A review, Journal of Geophysical Research: Space Physics, vol.95, issue.A11, pp.98-18879, 1993.
DOI : 10.1029/93JA01943

W. K. Tobiska and F. G. Eparvier, EUV97: Improvements to EUV Irradiance Modeling in the Soft X-Rays and FUV, Sol. Phys, vol.177, issue.12, pp.147-159, 1997.
DOI : 10.1007/978-94-011-5000-2_11

K. M. Aggarwal, J. Callaway, A. E. Kingston, and K. Unnikrishnan, Excitation rate coefficients for transitions among the n = 1, 2, and 3 levels of He + , Astrophys, Journ, vol.80, pp.473-477, 1992.

C. Achenbach, A. Müller, &. E. Salzborn, and R. Becker, Single ionisation of multiply charged xenon ions by electron impact, Journal of Physics B: Atomic and Molecular Physics, vol.17, issue.7, pp.1405-1425, 1984.
DOI : 10.1088/0022-3700/17/7/023

S. M. Aldrovandi and D. Péquignot, Radiative and Dielectronic Recombinaison Coefficients for Complex ions, Astron. Astrophys, vol.25, pp.137-140, 1973.

M. Arnaud and R. Rothenflug, An updated evaluation of recombination and ionization rates, Astron. Astrophys. Suppl. Ser, vol.60, pp.425-457, 1985.

K. Bartschat and I. Bray, Electron-impact ionization of atomic hydrogen from the 1S and 2S states, Journal of Physics B: Atomic, Molecular and Optical Physics, vol.29, issue.15, pp.577-583, 1996.
DOI : 10.1088/0953-4075/29/15/005

I. Bray, I. E. Mccarthy, J. Wigley, and A. T. Stelbovics, ion, Journal of Physics B: Atomic, Molecular and Optical Physics, vol.26, issue.23, pp.831-836, 1993.
DOI : 10.1088/0953-4075/26/23/006

URL : https://hal.archives-ouvertes.fr/hal-00617036

A. Burgess, Tables of hydrogenic photoinization cross-sections and recombination coefficients , Memoirs of the Roy, Astron. Soc, vol.69, pp.1-19, 1964.

A. Burgess, Delectronic Recombination and the Temperature of the Solar Corona., The Astrophysical Journal, vol.139, issue.2, pp.776-780, 1964.
DOI : 10.1086/147813

A. Burgess, A General Formula for the Estimation of Dielectronic Recombination Co-Efficients in Low-Density Plasmas., The Astrophysical Journal, vol.141, issue.4, pp.1588-1590, 1964.
DOI : 10.1086/148253

A. Burgess and A. S. Tworkowski, Dielectronic Recombination to Form Helium-Like Ions, The Astrophysical Journal, vol.205, pp.105-107, 1976.
DOI : 10.1086/182100

A. Burgess and J. A. Tuly, On the analysis of collisions strengths and rate coefficients, Astron. Astrophys, vol.254, pp.436-453, 1992.

P. Defrance, W. Claeys, A. Cornet, and G. Poulaert, Electron impact ionisation of metastable atomic hydrogen, Journal of Physics B: Atomic and Molecular Physics, vol.14, issue.1, pp.111-117, 1981.
DOI : 10.1088/0022-3700/14/1/013

K. P. Dere, E. Landi, H. E. Mason, B. C. Monsignori-fossi, and P. R. Young, CHIANTI - an atomic database for emission lines, Astronomy and Astrophysics Supplement Series, vol.125, issue.1, pp.149-173, 1997.
DOI : 10.1051/aas:1997368

A. J. Dixon, A. Von-engel, and M. F. Harrison, A Measurement of the Electron Impact Ionization Cross Section of Atomic Hydrogen in the Metastable 2S State, Proc. R. Soc. Lond, pp.333-349, 1975.
DOI : 10.1098/rspa.1975.0069

K. T. Dolder, M. F. Harrison, and P. C. Thoneman, A Measurement of the Ionization Cross-Section of Helium Ions by Electron Impact, Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, vol.264, issue.1318, pp.367-378, 1961.
DOI : 10.1098/rspa.1961.0205

V. I. Fisher, Y. V. Ralchenko, V. A. Bernshtam, A. Goldgirsh, Y. Maron et al., Electron-impact-excitation cross sections of hydrogenlike ions, Physical Review A, vol.55, issue.1, pp.329-334, 1997.
DOI : 10.1103/PhysRevA.55.329

D. V. Fursa and . Bray, Calculation of electron-helium scattering, Physical Review A, vol.52, issue.2, pp.1279-1297, 1995.
DOI : 10.1103/PhysRevA.52.1279

Y. Kim and M. E. Rudd, Binary-encounter-dipole model for electron-impact ionization, Physical Review A, vol.50, issue.5, pp.3954-3967, 1994.
DOI : 10.1103/PhysRevA.50.3954

URL : http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1026&context=physicsrudd

Y. Kim, W. R. Johnson, and M. E. Rudd, Cross sections for singly differential and total ionization of helium by electron impact, Physical Review A, vol.61, issue.3, p.34702, 2000.
DOI : 10.1103/PhysRevA.61.034702

H. H. Koller, Inaugural dissertation, 1975.

R. G. Montague, M. F. Harrison, and A. C. Smith, A measurement of the cross section for ionisation of helium by electron impact using a fast crossed beam technique, Journal of Physics B: Atomic and Molecular Physics, vol.17, issue.16, pp.3295-3310, 1984.
DOI : 10.1088/0022-3700/17/16/012

B. Peart, D. S. Walton, and K. T. Dolder, The ranges of validity of the Born and Bethe approximations for the single ionization of He+ and Li+ ions by electron impact, Journal of Physics B: Atomic and Molecular Physics, vol.2, issue.12, pp.1347-1352, 1969.
DOI : 10.1088/0022-3700/2/12/314

D. Péquignot, &. P. Petitjean, and C. Boisson, Total and effective radative recombination coefficients, Astron. Astrophys, vol.251, pp.680-688, 1991.

M. J. Seaton, Cross section for 2s-2p transitions in H and 3s-3p transitions in Na produces by electron and by proton impact, Proc. Phys. Soc, vol.6, issue.A, pp.457-473, 1954.

M. J. Seaton, Radiative Recombination of Hydrogenic Ions, Monthly Notices of the Royal Astronomical Society, vol.119, issue.2, pp.81-89, 1959.
DOI : 10.1093/mnras/119.2.81

M. B. Shah and H. B. Gilbody, ions, Journal of Physics B: Atomic and Molecular Physics, vol.18, issue.5, pp.899-913, 1985.
DOI : 10.1088/0022-3700/18/5/010

URL : https://hal.archives-ouvertes.fr/hal-01284155

M. B. Shah, D. S. Elliott, and H. B. Gilbody, Pulsed crossed-beam study of the ionisation of atomic hydrogen by electron impact, Journal of Physics B: Atomic and Molecular Physics, vol.20, issue.14, pp.3501-3514, 1987.
DOI : 10.1088/0022-3700/20/14/022

M. B. Shah, D. S. Elliott, P. Mccallion, and H. B. Gilbody, Single and double ionisation of helium by electron impact, Journal of Physics B: Atomic, Molecular and Optical Physics, vol.21, issue.15, pp.2751-2761, 1988.
DOI : 10.1088/0953-4075/21/15/019

K. Unnikrishnan and J. Callaway, Optical-popential study of electron-impact excitation of He +, Phys. Rev. A, issue.11, pp.43-5966, 1991.

D. A. Verner, E. M. Verner, and G. J. Ferland, Atomic Data for Permitted Resonance Lines of Atoms and Ions from H to Si, and S, Ar, Ca, and Fe, Atomic Data and Nuclear Data Tables, vol.64, issue.1, pp.1-180, 1996.
DOI : 10.1006/adnd.1996.0018

D. A. Verner and G. J. Ferland, Atomic Data for Astrophysics. I. Radiative Recombination Rates for H-like, He-like, Li-like, and Na-like Ions over a Broad Range of Temperature, The Astrophysical Journal Supplement Series, vol.103, pp.467-473, 1996.
DOI : 10.1086/192284

D. A. Verner, G. J. Ferland, and K. T. Korista, Atomic Data for Astrophysics. II. New Analytic FITS for Photoionization Cross Sections of Atoms and Ions, The Astrophysical Journal, vol.465, pp.487-498, 1996.
DOI : 10.1086/177435

S. M. Younger, Electron-impact-ionization cross sections and rates for highly ionized berylliumlike ions, Physical Review A, vol.24, issue.3, pp.1278-1285, 1981.
DOI : 10.1103/PhysRevA.24.1278

S. M. Younger, Electron impact ionization cross sections and rates for highly ionized atoms, Journal of Quantitative Spectroscopy and Radiative Transfer, vol.26, issue.4, pp.329-337, 1981.
DOI : 10.1016/0022-4073(81)90127-8

S. M. Younger, Cross sections and rates for direct electron-impact ionization of sodiumlike ions, Physical Review A, vol.24, issue.3, pp.1272-1277, 1981.
DOI : 10.1103/PhysRevA.24.1272

C. W. Allen, Astrophysical quantities, The athlone press university of London, 1973.

E. H. Avrett, Combined effects of mass flows and particule diffusion on the ionization structure of the solar transition region Plasmas Dynamics and Diagnostics in the Solar Transition Region and Corona, Eigth SOHO Workshop, pp.141-144, 1999.

S. Baumbach, Strahlung, Ergiebigkeit und Elektronendichte der Sonnenkorona, Astronomische Nachrichten, vol.1, issue.6, pp.121-134, 1972.
DOI : 10.1002/asna.19372630602

W. E. Behring, L. Cohen, and U. Feldman, The Solar Spectrum: Wavelengths and Identifications from 60 TO 385 Angstroms, The Astrophysical Journal, vol.175, pp.493-523, 1972.
DOI : 10.1086/151575

J. W. Brault and O. R. White, The analysis and restoration of astronomical data via the fast fourier transform, Astron. Astrophys, vol.13, pp.169-189, 1971.

J. W. Brosius, J. M. Davila, and R. J. Thomas, Measuring Active and Quiet-Sun Coronal Plasma Properties with Extreme-Ultraviolet Spectra from SERTS, The Astrophysical Journal Supplement Series, vol.106, pp.143-164, 1996.
DOI : 10.1086/192332

R. M. Broussard, N. R. Sheeley, R. Tousey, and J. H. Underwood, A survey of coronal holes and their solar wind associations throughout sunspot cycle 20, Solar Physics, vol.15, issue.1, pp.161-183, 1978.
DOI : 10.1007/BF00152641

G. E. Brueckner, R. A. Howard, M. J. Koomen, C. M. Korendyke, D. J. Michels et al., The Large Angle Spectroscopic Coronagraph (LASCO), The Large Angle spectroscopic coronograph (LASCO), Visible light coronal imaging and spectroscopy, pp.357-402, 1995.
DOI : 10.1007/BF00733434

G. W. Cushman, G. Godden, and W. A. Rense, Solar line profiles in range 200 A - 700 A, Meeting of the Solar Physics Division, p.285, 1974.

G. W. Cushman, L. Farwell, G. Godden, and W. A. Rense, Solar line profiles of He I 584 A and He II 304 A, Journal of Geophysical Research, vol.186, issue.4, pp.482-486, 1975.
DOI : 10.1029/JA080i004p00482

G. W. Cushman and W. A. Rense, Solar Heii(304 ???) and Si xi(303 ???) line profiles, Solar Physics, vol.57, issue.2, pp.299-305, 1978.
DOI : 10.1007/BF00157275

C. David, A. H. Gabriel, F. Bely-dubau, A. Fludra, P. Lemaire et al., Measurement of the electron tempreature gradient in a solar coronal hole, Astron. Atrsophys. Lett, vol.336, pp.90-94, 1998.

G. A. Doschek, W. E. Behring, and U. Feldman, The Widths of the Solar he i and he II Lines at 584, 537, and 304 ??, The Astrophysical Journal, vol.190, pp.141-142, 1974.
DOI : 10.1086/181526

R. Esser, S. R. Habbal, G. L. Withbroe, and E. Leer, A two-fluid solar wind model with Alfven waves: Parameter study and application to observations, Journal of Geophysical Research, vol.297, issue.A3, pp.2950-2960, 1986.
DOI : 10.1029/JA091iA03p02950

U. Feldman and W. E. Behring, Solar Coronal Line Profiles in the Extreme-Ultraviolet, The Astrophysical Journal, vol.189, pp.45-46, 1974.
DOI : 10.1086/181460

R. R. Fisher, R. H. Lee, R. M. Macqueen, and A. I. Poland, New Mauna Loa coronagraph systems, Applied Optics, vol.20, issue.6, pp.1094-1101, 1981.
DOI : 10.1364/AO.20.001094

A. H. Gabriel, Measurements on the Lyman alpha corona, Solar Physics, vol.136, issue.2, pp.393-400, 1971.
DOI : 10.1007/BF00154290

L. Golub and J. M. Pasachoff, The solar corona The Edimburg building, 1997.

V. H. Hansteen, E. Leer, and T. E. Holzer, The Role of Helium in the Outer Solar Atmosphere Astrophys, Journ, vol.482, pp.498-509, 1997.

R. A. Harrison, E. C. Sawyer, M. K. Carter, A. M. Cruise, R. M. Cutler et al., The Coronal Diagnostic Spectrometer for the solar and heliospheric observatory, Solar Physics, vol.37, issue.386, pp.233-290, 1995.
DOI : 10.1007/BF00733431

S. D. Jordan, Line formation and intensity enhancement of the HeII 304Åline304?304Åline in the solar atmosphere, IAU coloq. 144 " Solar Coronal Structures, 1994.

Y. Ko, L. A. Fisk, J. Geiss, G. Gloeckler, and M. Guhathakurta, An Empirical Study of the Electron Temperature and Heavy Ion Velocities in the South Polar Coronal Hole, Solar Physics, vol.171, issue.2, pp.345-361, 1997.
DOI : 10.1023/A:1004943213433

S. Koutchmy and G. Stellmacher, Photometric study of chromospheric and coronal spikes observed during the total solar eclipse of, Sol. Phys, vol.46, pp.253-265, 1973.

J. M. Laming and U. Feldman, Measuring the Solar Helium Abundance in the Outer Corona with SumerPlasma Dynamics ans Diagnostics in the Solar Transition Region and Corona', Proc. 8 t h SOHO Workshop, pp.405-410, 1999.

L. B. Lucy, An iterative technique for the rectification of observed distributions, The Astronomical Journal, vol.79, issue.6, pp.745-753, 1974.
DOI : 10.1086/111605

J. D. Mangus, Optical Design of Glancing Incidence Extreme Ultraviolet Telescopes, Applied Optics, vol.9, issue.5, pp.1019-1025, 1970.
DOI : 10.1364/AO.9.001019

W. M. Neupert, L. E. Gabriel, and R. J. Thomas, An EUV imaging spectrograph for high-resolution observations of the solar corona, Solar Physics, vol.16, issue.11, pp.87-104, 1992.
DOI : 10.1007/BF00146577

J. S. Newmark, Solar Temperature Diagnostics Based Upon Observations by the SOHO Extreme ultraviolet Imaging Telescope, EOS, issue.46, pp.77-557, 1996.

G. Noci, J. L. Kohl, and G. L. Withbroe, Solar wind diagnostics from Doppler-enhanced scattering, The Astrophysical Journal, vol.315, pp.706-715, 1987.
DOI : 10.1086/165172

J. T. Nolte, J. M. Davis, M. Gerassimenko, A. S. Krieger, and C. V. Solodyna, The relationship between solar activity and coronal hole evolution, Solar Physics, vol.206, issue.1, pp.143-153, 1978.
DOI : 10.1007/BF00152339

B. E. Patchett, K. Norman, A. H. Gabriel, and J. L. Culhane, The Coronal Helium Abundance Experiment on Spacelab 2, Space Science Reviews, vol.29, issue.4, pp.431-437, 1981.
DOI : 10.1007/BF00239488

W. H. Richardson, Bayesian-Based Iterative Method of Image Restoration*, Journal of the Optical Society of America, vol.62, issue.1, pp.55-59, 1972.
DOI : 10.1364/JOSA.62.000055

P. C. Russell, Further Soft X-ray Images of the Sun, Nature, vol.205, issue.4981, pp.281-282, 1965.
DOI : 10.1038/206281a0

P. C. Russell and K. A. Pounds, Improved Resolution X-ray Photographs of the Sun, Nature, vol.28, issue.5022, pp.490-491, 1966.
DOI : 10.1038/209490a0

A. F. Timothy, A. S. Krieger, and G. S. Vaiana, The structure and evolution of coronal holes, Solar Physics, vol.14, issue.1, pp.135-156, 1975.
DOI : 10.1007/BF00153291

R. Tousey, Some Results of Twenty Years of Extreme Ultraviolet Solar Research, The Astrophysical Journal, vol.149, issue.2, pp.239-252, 1967.
DOI : 10.1086/149249

W. Waniak, Image restoration by simple adaptive deconvolution, Astronomy and Astrophysics Supplement Series, vol.124, issue.1, pp.197-203, 1997.
DOI : 10.1051/aas:1997190

P. R. Young, J. A. Klimchuk, and A. E. Mason, Temperature and density in a polar plume-measurements from CDS/SOHO, Astron. Atrophys, vol.350, pp.286-301, 1999.

E. H. Avrett, Combined effects of mass flows and particule diffusion on the ionization structure of the solar transition region Plasmas Dynamics and Diagnostics in the Solar Transition Region and Corona, Eigth SOHO Workshop, pp.141-144, 1999.

J. W. Brosius, J. M. Davila, and R. J. Thomas, Measuring Active and Quiet-Sun Coronal Plasma Properties with Extreme-Ultraviolet Spectra from SERTS, The Astrophysical Journal Supplement Series, vol.106, pp.143-164, 1996.
DOI : 10.1086/192332

C. David, A. H. Gabriel, F. Bely-dubau, A. Fludra, P. Lemaire et al., Measurement of the electron tempreature gradient in a solar coronal hole, Astron. Atrsophys. Lett, vol.336, pp.90-94, 1998.

K. P. Dere, J. D. Moses, J. Delaboudinì-ere, J. Brunaud, C. Carabetian et al., The Preflight Photometric Calibration of the Extreme-ultraviolet Imaging Telescope EIT, Solar Physics, vol.195, issue.1, pp.13-44, 2000.
DOI : 10.1023/A:1005288008723

S. R. Habbal and R. Esser, On the Derivation of Empirical Limits on the Helium Abundance in Coronal Holes below 1.5 R s, Astrophys. Journ, vol.421, pp.49-62, 1994.
DOI : 10.1007/978-94-011-0167-7_6

V. H. Hansteen, E. Leer, and T. E. Holzer, The Role of Helium in the Outer Solar Atmosphere, The Astrophysical Journal, vol.482, issue.1, pp.498-509, 1997.
DOI : 10.1086/304111

D. M. Hassler, D. C. Slater, R. N. Smartt, and S. Koutchmy, SOPHIE: a solar EUV multilayer reflecting coronagraph, Proc. SPIE, X-Ray and Ultraviolet Spectroscopy and Polarimetry II, pp.61-66, 1998.
DOI : 10.1117/12.333601

L. Poletto, G. Naletto, P. Nicolosi, G. Tondello, and L. D. Gardner, <title>Optical configurations for the EUV channels of the Advanced Solar Coronal Explorer mission</title>, Ultraviolet and X-Ray Detection, Spectroscopy, and Polarimetry III, 1999.
DOI : 10.1117/12.371096

C. W. Allen, Allen's astrophysical quantities Fourth edition, 2000.

E. Anders and N. Grevesse, Abundances of the elements: Meteoritic and solar, Geochimica et Cosmochimica Acta, vol.53, issue.1, p.197, 1989.
DOI : 10.1016/0016-7037(89)90286-X

K. P. Dere, E. Landi, H. E. Mason, B. C. Monsignori-fossi, and P. R. Young, CHIANTI - an atomic database for emission lines, Astronomy and Astrophysics Supplement Series, vol.125, issue.1, pp.149-173, 1997.
DOI : 10.1051/aas:1997368

U. Feldman, P. Mandelbaum, J. L. Seely, G. A. Doschek, and H. Gursky, The potential for plasma diagnostics from stellar extreme-ultraviolet observations, Astrophys, Jour, vol.81, issue.1, pp.387-408, 1992.

N. Grevesse and E. Anders, Solar Element Abundances, in Solar Interior and Atmosphere, pp.1227-1234, 1991.

N. Grevesse and A. J. Sauval, Standard Solar Composition, Space Sci. Rev, vol.85, issue.12, pp.161-174, 1998.
DOI : 10.1007/978-94-011-4820-7_15

P. G. Judge, T. N. Woods, P. Brekke, and G. J. Rottman, On the Failure of Standard Emission Measure Analysis for Solar Extreme-Ultraviolet and Ultraviolet Irradiance Spectra, The Astrophysical Journal, vol.455, issue.1, pp.85-88, 1995.
DOI : 10.1086/309815

J. P. Meyer, Solar-stellar outer atmospheres and energetic particles, and galactic cosmic rays, The Astrophysical Journal Supplement Series, vol.57, pp.173-204, 1985.
DOI : 10.1086/191001

J. T. Schmelz, J. L. Saba, and K. T. Strong, Resonance scattering of Fe XVII - A density diagnostic, The Astrophysical Journal, vol.398, issue.2, pp.115-118, 1992.
DOI : 10.1086/186590

K. Waljeski, D. Moses, K. P. Dere, J. L. Saba, K. T. Strong et al., The composition of a coronal active region, The Astrophysical Journal, vol.429, issue.2, pp.909-923, 1994.
DOI : 10.1086/174375

P. R. Young, H. E. Mason, F. P. Keenan, and K. G. Widing, The Ar/Ca relative abundance in solar coronal plasma, Astron. Astrophys, vol.323, pp.243-249, 1997.

P. La and . Eitàeit, EITà 19.5 nm obtenuè a partir de l'image de l'´ eruption de la figure 3.2, p.48

+. He, Coefficients de recombinaison totaux de He 2+ vers He + , et de He + vers He, et coefficients partiels de He 2+ vers les niveaux 2s, 2p, 3s, pp.3-3

T. De-la, Facteur de profil en fonction de la vitesse relative des ions He + par rapportàrapport`rapportà la surface de la chromosphère et en fonction, p.170

P. La and E. .. , Intensité d'un disque unité de 10.1 " de diamètre convolué avec, p.57

F. Auchère, S. Boulade, S. Koutchmy, R. N. Smartt, J. Delaboudinì-ere et al., The Prolate Solar Chromosphere, Astronomy & Astrophysics, vol.336, pp.57-60, 1998.

F. Auchère, C. E. Deforest, and G. Artzner, In-Flight Determination of the Plate Scale of the Extreme-Ultraviolet Imaging Telescope, -flight Determination of the Plate Scale of the EIT, p.115, 2000.
DOI : 10.1086/312471

F. Auchère, Stray-light calibration of the EIT, Third EIT Consortium Meeting, 2000.

F. Auchère, The Plate Scale of the EIT, Third EIT Consortium Meeting, 2000.

F. Auchère and J. &delaboudinì-ere, Helium Abundance in the Solar Corona, Helium Lines Formation in a Dynamic Atmosphere workshop, 2000.

F. Auchère, D. M. Hassler, D. C. Slater, and T. N. Woods, <title>SwRI/LASP sounding rocket intercalibration with the EIT instrument on board SoHO</title>, EUV, X-Ray, and Gamma-Ray Instrumentation for Astronomy X, pp.351-359, 1999.
DOI : 10.1117/12.366516

F. Auchère and J. &delaboudinì-ere, Detection of Singly Ionized Helium in the Solar Corona, EOS transactions, 1999.

G. Artzner, F. Auchère, J. Delaboudinì-ere, and J. Hochedez, Equivalent focal length measurements, Design and Engineering of Optical Systems II, pp.32-36, 1999.
DOI : 10.1117/12.360014

J. M. Defise, F. Clette, and F. Auchère, In-flight Characterization and Compensation of the Optical Properties of the EIT Instrument, Proc. SPIE, EUV, X-Ray, and Gamma-Ray Instrumentation for Astronomy, pp.341-350, 1999.

S. Koutchmy, D. Folco, E. Auchère, F. Baudin, and F. , The Solar Prolateness Effect, Proceedings of the 8th SOHO workshop, 1999.

J. M. Defise, F. Clette, and F. Auchère, In-flight Characterization and Compensation of the Optical Properties of the EIT Instrument, Proc. SPIE, EVE, X-Ray, and Gamma-Ray Instrumentation for Astronomy, pp.341-350, 1999.

T. Fredvik, O. Kjeldseth-moe, P. Brekke, S. V. Haugan, T. D. Tarbell et al., An Eruption in an Active Region Loop System Observed with TRACE, CDS and EIT, Proceedings of the TRACE Monterey meeting, 1999.

D. J. Michels, S. T. Wu, A. Wang, S. Plunkett, and F. Auchère, The Minimum Corona - Baseline for Study of CME Disturbances, EOS transactions, 1999.