Electromagnetic and corpuscular emission from the solar flare of 1991 June 15: Continuous acceleration of relativistic particles

• Published in: Solar physics Vol. 150; no. 2-Jan; pp. 267 - 283
• Main Authors: Kocharov, L. G., Kovaltsov, G. A., Kocharov, G. E., Chuikin, E. I., Usoskin, I. G., Shea, M. A., Smart, D. F., Melnikov, V. F., Podstrigach, T. S., Armstrong, T. P.
• Format: Journal Article
• Language: English
• Published: Legacy CDMS Reidel 01-03-1994
• Subjects: Solar Physics
• ISSN: 0038-0938; 1573-093X
• DOI: 10.1007/BF00712889

Data on X-, gamma-ray, optical and radio emission from the 1991 June 15 solar flare are considered. We have calculated the spectrum of protons that produces gamma-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 approximately equal to 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 producing gamma-ray line emission. In the gradual phase of the flare additional pulses of energy release occurred and the time profiles of cm-radio emission and gamma-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.