The Yohkoh context for high-energy particles in solar flares
Abstract
Yohkoh, a satellite dedicated to high-energy observations of solar flares, began observations in September, 1991. It carries (i) a soft X-ray telescope with arcsecond resolution and excellent temporal sampling; (ii) a hard X-ray imager making the first images above 30 keV; (iii) a sensitive Bragg crystal spectrometer for soft X-ray emission lines; and (iv) a set of proportional and scintillation counters. The flare observations confirm the central role of impulsive-phase electron acceleration in causing ``evaporation'' and white-light flare emission. SXT has found impulsive soft X-ray time profiles at the footpoints. It also shows compact bright structures apparently at the tops of flaring loops during the gradual phase. Large flares may show cusp-shaped structures that strongly resemble the usual picture of coronal magnetic reconnection, but otherwise do not match the details of the classical flare scenario. The data taken as a whole suggest that large-scale magnetic reconnection in the solar corona does not drive flare energy release, but rather is driven by the flare; the reconnection may have an important role in flare triggering.
- Publication:
-
High-Energy Solar Phenomena - a New Era of Spacecraft Measurements
- Pub Date:
- December 1994
- DOI:
- 10.1063/1.45184
- Bibcode:
- 1994AIPC..294..151H
- Keywords:
-
- 96.60.Rd;
- 96.40.Fg;
- 96.60.Pb