White Light Events as Photospheric Flares
Abstract
We consider the possibility that white light flares are due to heating of the photosphere by a flux of energetic ions and electrons impinging on it from above. Particles with energy in the range 10 MeV to 1 BeV release most of their energy to the ambient gas at about optical depth unity in the photosphere. This increase in energy produces a temperature perturbation of several hundred degrees in the layer and results in a re-radiation of the energy with a radiative relaxation time of several seconds. The consequences of this model are applied to a study of the great flare of May 23, 1967 and to the very fast event of August 11, 1954. Large numbers of very energetic electrons or protons must be produced in the first few minutes of the primary flare event if our interpretation (or one based on synchrotron emission) is correct.
- Publication:
-
Solar Physics
- Pub Date:
- November 1970
- DOI:
- 10.1007/BF00149484
- Bibcode:
- 1970SoPh...15..176N
- Keywords:
-
- Relaxation Time;
- Flare;
- Optical Depth;
- Energetic Electron;
- Temperature Perturbation