Probing the solar wind acceleration region using spectroscopic techniques

Measurements of the intensities and profiles of UV and EUV spectral lines can provide a powerful tool for probing the physical conditions in the solar corona out to 8 R⊙ and beyond. We discuss here how measurements of spectral line radiation in conjunction with measurements of the white light K-corona can provide information on electron, proton and ion temperatures and velocity distribution functions; densities; chemical abundances and mass flow velocities. Because of the fundamental importance of such information, we provide a comprehensive review of the formation of coronal resonance line radiation, with particular emphasis on the H i Lα line, and discuss observational considerations such as requirements for rejection of stray light and effects of emission from the geocorona and interplanetary dust. Finally, we summarize some results of coronal H i Lα and white light observations acquired on sounding rocket flights.

[1]  L. Cram.  Determination of the temperature of the solar corona from the spectrum of the electron-scattering continuum , 1976 .

[2]  G. W. Cushman,et al.  Evidence of outward flow of plasma in a coronal hole , 1976 .

[3]  Stuart D. Jordan,et al.  The sun as a star , 1981 .

[4]  W. E. Behring,et al.  Solar coronal line profiles in the extreme-ultraviolet , 1974 .

[5]  R. J. Speer,et al.  Rocket observations of the ultraviolet solar spectrum during the total eclipse of 1970 March 7 , 1971 .

[6]  R. Rosner,et al.  Recent advances in coronal physics. , 1978 .

[7]  Jacques M. Beckers,et al.  The profile and polarization of the coronal Lα line , 1974 .

[8]  W. Fite,et al.  Charge transfer in collisions involving symmetric and asymmetric resonance , 1962, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[9]  T. Holzer,et al.  A steady three‐fluid coronal expansion for nonspherical geometries , 1978 .

[10]  M. Altschuler,et al.  Improved three-dimensional mapping of the electron density distribution of the solar corona , 1973 .

[11]  J. Kohl,et al.  EUV spectroscopic plasma diagnostics for the solar wind acceleration region , 1982 .

[12]  J. Hirshberg.  Composition of the solar wind: Present and past , 1975 .

[13]  G. Vaiana,et al.  New instrumentation for space astronomy , 1978 .

[14]  G. Withbroe.  Solar XUV limb brightening observations , 1970 .

[15]  G. Newkirk.  Structure of the Solar Corona , 1967 .

[16]  G. Noci,et al.  Analysis of coronal H I Lyman alpha measurements from a rocket flight on 1979 April 13 , 1982 .

[17]  J. Hollweg,et al.  Some physical processes in the solar wind , 1978 .

[18]  O. White.  The Solar Output and Its Variation , 1977 .

[19]  M. Ingham.  The nature and distribution of the interplanetary dust , 1961 .

[20]  A. Code,et al.  The scientific results from the Orbiting Astronomical Observatory (OAO-2) , 1972 .

[21]  J. Linsky,et al.  Lyman-alpha rocket spectra and models of the quiet and active solar chromosphere based on partial redistribution diagnostics , 1979 .

[22]  R. Howard.  Magnetic Field of the Sun (Observational) , 1967 .

[23]  K. Nicolas,et al.  Emission measures, electron densities, and nonthermal velocities from optically thin UV lines near a quiet solar limb. , 1977 .

[24]  George L. Withbroe,et al.  Mass and Energy Flow in the Solar Chromosphere and Corona , 1977 .

[25]  G. Newkirk,et al.  Magnetic fields and the structure of the solar corona , 1970 .

[26]  P. Sturrock,et al.  Two-Fluid Model of the Solar Wind , 1968 .

[27]  Faculteit der Wiskunde en Natuurwetenschappen,et al.  Zodiacal Light in the Solar Corona. , 1947 .

[28]  E. M. Reeves,et al.  The Extreme-Ultraviolet Spectrum of the Quiet Sun , 1971 .

[29]  G. Rottman,et al.  Measurement of systematic outflow from the solar transition region underlying a coronal hole , 1981 .

[30]  I. Percival.  Cross sections for collisions of electrons with hydrogen atoms and hydrogen-like ions , 1966 .

[31]  W. Feldman,et al.  The quiet corona: Temperature and temperature gradient , 1974 .

[32]  J. Vial,et al.  The solar hydrogen Lyman-beta and Lyman-alpha lines: disk center observations from OSO 8 compared with theoretical profiles. , 1978 .

[33]  D. K. Prinz.  The spatial distribution of Lyman-$alpha$ on the Sun , 1974 .

[34]  C. J. Hughes.  PROFILES OF LYMAN-ALPHA SCATTERED BY FREE ELECTRONS IN THE SOLAR CORONA , 1965 .

[35]  E. M. Reeves,et al.  Extreme ultraviolet composite spectra of representative solar features , 1978 .

[36]  E. M. Reeves,et al.  The extreme-ultraviolet spectrum of a solar active region. , 1973 .

[37]  A. H. Cook,et al.  Astrophysical Quantities C. W. Allen (University of London, Athlone Press, 291 + xi pp., 63s.) , 1963 .

[38]  E. M. Reeves,et al.  Measurements of coronal kinetic temperatures from 1.5 to 3 solar radii , 1980 .

[39]  C. Hyder,et al.  Hα Doppler brightening and Lyman-α Doppler dimming in moving Hα prominences , 1970 .

[40]  B. Mcintosh,et al.  Solid Particles in the Solar System , 1980 .

[41]  G. Brueckner.  A high-resolution view of the solar chromosphere and corona , 1980 .

[42]  I. A. Ahmad.  Coronal He+ λ304 radiation , 1977 .

[43]  A. Hundhausen,et al.  Coronal Expansion and Solar Wind , 1972 .

[44]  A. Gabriel.  Measurements on the Lyman alpha corona , 1971 .

[45]  George L. Withbroe,et al.  The spacelab Lyman alpha and white light coronagraphs program , 1980 .

[46]  A. Barnes,et al.  A reexamination of two-fluid solar wind models , 1977 .

[47]  L. Spitzer.  Physics of fully ionized gases , 1956 .

[48]  B. Jackson,et al.  Physical properties of a polar coronal hole from 2 to 5 solar radii , 1977 .

[49]  D. E. Routh,et al.  Pinhole Occulter Facility , 1984, Other Conferences.