Accession Number : AD0621195

Title :   HE I EXCITATION IN CHROMOSPHERIC FLARES,

Corporate Author : SACRAMENTO PEAK OBSERVATORY SUNSPOT N MEX

Personal Author(s) : Steshenko,N. V. ; Khokhlova,V. L.

Report Date : 1965

Pagination or Media Count : 24

Abstract : The study of 11 emission lines of parahelium and orthohelium in the flare of August 30, 1959, and also several lines in other flares, shows that the optical depth of the helium lines is small in the wavelength region 37006700 A of flares observed on the solar disk and at the limb. The population of excited He I levels is derived from the energy of the lines, taking into account the optical depth of non-transparent lines. The line-widths are used for obtaining the upper limit of kinetic temperature in the He I emission region, assuming that line broadening is due only to the thermal velocities of the atoms. The population of the He I levels is computed theoretically. For this purpose the statical equilibrium equations and that of ionization equilibrium are solved for parahelium and orthohelium together. It is shown that excitation by electron impact and recombination can be provided for the observed emission. The possibility of heating of the optical emission region of the flare due to the absorption of X-ray radiation of the flare is considered. The observed flux of X-ray radiation and the energy output of the flare in the ultraviolet and visual spectral regions can be provided for if the color temperature of the core of the flare is approx. 5,000,000K. (Author)

Descriptors :   (*HELIUM, SOLAR ATMOSPHERE), (*SOLAR ATMOSPHERE, LINE SPECTRA), (*SOLAR FLARES, LINE SPECTRA), ATOMIC ENERGY LEVELS, EXCITATION, TEMPERATURE, GAS IONIZATION, CHEMICAL EQUILIBRIUM, RECOMBINATION REACTIONS, X RAYS, ABSORPTION, ELECTRON TRANSITIONS, USSR

Distribution Statement : APPROVED FOR PUBLIC RELEASE