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Structure of the solar chromosphere. III - Models of the EUV brightness components of the quiet-sun
Vernazza, J. E.; Avrett, E. H.; Loeser, R.
AA(California, University, Livermore, CA; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA), AB(Harvard-Smithsonian Center for Astrophysics, Cambridge, MA), AC(Harvard-Smithsonian Center for Astrophysics, Cambridge, MA)
Astrophysical Journal Supplement Series, vol. 45, Apr. 1981, p. 635-725. (ApJS Homepage)
Publication Date:
Solar Physics
NASA/STI Keywords:
Atmospheric Models, Brightness Temperature, Chromosphere, Extreme Ultraviolet Radiation, Nonequilibrium Thermodynamics, Radiative Heat Transfer, Solar Atmosphere, Ultraviolet Spectra, Atmospheric Heating, Atomic Energy Levels, Carbon, Graphs (Charts), Hydrogen Atoms, Iron, Lyman Spectra, Solar Temperature, Tables (Data)
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The described investigation is concerned with the solution of the non-LTE optically thick transfer equations for hydrogen, carbon, and other constituents to determine semiempirical models for six components of the quiet solar chromosphere. For a given temperature-height distribution, the solution is obtained of the equations of statistical equilibrium, radiative transfer for lines and continua, and hydrostatic equilibrium to find the ionization and excitation conditions for each atomic constituent. The emergent spectrum is calculated, and a trial and error approach is used to adjust the temperature distribution so that the emergent spectrum is in best agreement with the observed one. The relationship between semiempirical models determined in this way and theoretical models based on radiative equilibrium is discussed by Avrett (1977). Harvard Skylab EUV observations are used to determine models for a number of quiet-sun regions.

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