On the rate of energy input in thermal solar flares
Abstract
The rise phases of solar soft X-ray flares observed by X-ray crystal spectrometers on p78-1 are discussed in terms of the rate of change of X-ray flux as a function of time. It is shown that the flux increased exponentially over most of the rise time. The e-folding time TAU has a cut-off at 13 s. Soft X-ray flares with smaller values of TAU are not observed. It is suggested that this phenomenon is due to the ability of the solar atmosphere to absorb the input energy and convert it into a typical soft X-ray flare. For energy input rates that are below a certain critical value the temperature attained by the plasma is around 20,000,000 K, but for values above the critical value, the gas is heated to much higher temperatures Te > or = 10 to the 8th K, producing a certain class of hard X-ray events.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- December 1983
- Bibcode:
- 1983STIN...8423548F
- Keywords:
-
- Energy Levels;
- Flux (Rate);
- Solar Flares;
- Solar X-Rays;
- Energy Transfer;
- Solar Atmosphere;
- Spectrometers;
- X Ray Spectroscopy;
- Solar Physics