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Session 70 - Solar Flares and Ejections.
Display session, Thursday, June 13
Tripp Commons,

[70.10] Impulsive 7-10 keV Solar X-ray Bursts

P. T. Feffer, R. P. Lin (Univ. of California, Berkeley), R. A. Schwartz (GSFC)

We report on new evidence for accelerated electrons down to \sim7-10 keV in solar flares. Using the BATSE Spectroscopy Detectors, which have an effective area more than 10-100 times that of any solar observing instrument to date in this energy range, we have identified 144 events in \sim30 hours of data during 1-2 October 1991. 76 of these events have no observable >25 keV hard X-rays in the BATSE Large Area Detectors, and 37 of these soft events have an e--folding decay time <30 seconds. The impulsive nature of these events, as compared to the GOES-measured 0.5-4.0 Angstrom thermal emission, suggests that they originate from non-thermal accelerated electrons. We find the best-fit power-law photon spectra and estimate that the average rate of energy release in accelerated electrons may be comparable to the amount of energy needed to heat the corona. These events may also be the low-energy extension of the microflares observed previously using instruments that were sensitive only at energies >20 keV.

Program listing for Thursday