Contribution of solar-flare X-radiation to the heating of the flare's low-temperature /optical/ region
Abstract
It is noted that a significant portion of solar-flare X-radiation is absorbed in the chromosphere under a region of high-temperature plasma and that approximately one third of the X-ray flux incident on the chromosphere is absorbed at depths where optical emission (particularly H-alpha) originates. Calculations are performed which indicate that X-ray heating of the chromosphere may be the cause of the diffuse H-alpha halo observed around flares. It is suggested that X-ray heating of low-temperature flare regions may also enhance the optical emission from flare kernels. It is concluded that X-ray heating may be the dominant heating mechanism for the optical region of thermal flares characterized by a soft nonthermal-electron spectrum or the absence of nonthermal electrons at high flare-plasma temperatures. The calculations are applied to the flares of August 2 and 7, 1972.
- Publication:
-
Cosmic Rays in the Stratosphere and in Near Space (Russian)
- Pub Date:
- 1976
- Bibcode:
- 1976crsn.book..127S
- Keywords:
-
- Atmospheric Heating;
- Chromosphere;
- Solar Flares;
- Solar X-Rays;
- Energy Spectra;
- H Alpha Line;
- High Temperature Plasmas;
- Low Temperature;
- Radiant Heating;
- Solar Physics