EGRET Analysis of the Solar Nuclear Line Flares of June , 1991

Session 68 -- Solar Activity
Oral presentation, Thursday, January 13, 2:15-3:45, Salons A/B Room (Crystal City Marriott)

[68.04] EGRET Analysis of the Solar Nuclear Line Flares of June , 1991

E.J. Schneid (Grumman),D.L. Bertsch, C.E. Fichtel, R.C. Hartman, S.D. Hunter, D.J. Thompson, (NASA/GSFC), B.L. Dingus, P. Sreekumar (USRA/GSFC), G. Kanbach, H.A. Mayer-Hasselwander, C. von Montigny (MPE), Y.C. Lin, P.F. Michelson, P.L. Nolan (Stanford), D.A. Kniffen (Hampden-Sydney), J.R. Mattox (CSC/GSFC)

During June 1991 , the Energetic Gamma Ray Experiment Telescope on the Compton Observatory observed the four energetic flares occuring on June 4,6,9 and 11 from the active solar region 6659. Spectral and temporal data were obtained with EGRET's large NaI detector and imaging spark chamber . The June 11 flare was observed to have gamma-rays exceeding 1 GeV and last for hours after the impulsive phase. The NaI spectra have been fit with a power law spectrum, a neutron capture spectrum and a solar excitation spectrum . From these fits , the fluences of the 2.223 MeV neutron capture line and the 4.43 Mev carbon excitation line have been estimated for each flare. An additional spectral component corresponding to neutron induced activity in the Compton Observatory is required for the intense flares of June 4 and June 6. This component provides an indication of the arrival times of solar neutrons at the Observatory.

Thursday program listing