Gamma-Ray Precursors of Solar Flares

Abstract

Bursts have been observed by the gamma-ray spectrometer on SMM at medium-and high-energy gamma-rays that precede the flare maximum. The negligible contribution of nuclear lines in the spectra of these events and their impulsive appearance suggests that they are hard-electron-dominated events superposed on the flares. Spatial resolution at gamma-ray energies will be necessary to decide whether this kind of bursts is cospatial with the flares or whether they occur in the flares' vicinity.

Solar Neutrons and Related Phenomena

“…Both of these emissions decay with nearly identical time constants. Rieger (1994) reported bursts of g-ray emission on the rising portion of three SMM/GRS flares but concluded that the emission was most probably electron bremsstrahlung. Using COMPTEL data, Rank et al ( , 1997a) obtained a similar conclusion for the extended emission phases of the 1991 June 9, 11, and 15 flares.…”