Conditions for energetic flares
Abstract
Hard X-ray emission is commonly observed in association with solar flares and it is believed to signify interactions of accelerated electrons with the ambient ions. As a first step to understand what conditions are conducive to acceleration of electrons in solar flares, we have analyzed Yohkoh X-ray images for a total of four-dozen events whose hard X-ray spectra extend at least to 100 keV. The morphology of soft X-ray emission relative to hard X-ray sources shows a wide variety, but it is usually confined in a compact loop, which is sometimes topped with a cusp that is much more diffuse. While eruptive behaviors are often seen in the soft X-ray images, it is hard to decide whether they trigger or result from the nonthermal processes. We give a case study which indicates that double hard X-ray sources do not always come from conjugate footpoints of a loop.
- Publication:
-
High energy solar Physics
- Pub Date:
- June 1996
- DOI:
- 10.1063/1.50993
- Bibcode:
- 1996AIPC..374..294N
- Keywords:
-
- 96.60.Tf;
- 96.60.Rd;
- 96.40.Fg;
- Solar electromagnetic emission