Electromagnetic and corpuscular emission from the solar flare of 1991 June 15: Continuous acceleraton of relativistic particles
Data on X-,γ-ray, optical and radio emission from the 1991 June 15 solar flare are considered. We have calculated the spectrum of protons that producesγ-rays during the gradual phase of the flare. The primary proton spectrum can be described as a Bessel-function-type up to 0.8 GeV and a power law with the spectral index ≈3 from 0.8 up to 10 GeV or above. We have also analyzed data on energetic particles near the Earth. Their spectrum differed from that of primary protons producingγ-ray line emission. In the gradual phase of the flare additional pulses of energy release occurred and the time profiles of cm-radio emission andγ-rays in the 0.8–10 MeV energy band and above 50 MeV coincided. A continuous and simultaneous stochastic acceleration of the protons and relativistic electrons at the gradual phase of the flare is considered as a natural explanation of the data.
© 1994 Kluwer Academic Publishers. Provided by the NASA Astrophysics Data System. Received 25 June, 1993. It is a pleasure to acknowledge helpful discussions on these topics with Prof. J. A. Simpson and Prof. V. Petrosian. We are grateful to Dr E. V. Vashenyuk for providing material discussed here. GOES X-ray information used in this study was provided by WDC-A for Solar Terrestrial Physics, NOAA E/GC2, 325 Broadway, Boulder, Colorado 80303, U.S.A. The research at Big Bear Solar Observatory and in St. Petersburg was supported by NSF under Grant ATM-9122023 under Grant NAGW-1972.
Published - 1994SoPh__150__267K.pdf