Very energetic gamma-rays from the 3 June 1982 solar flare

Abstract

The Gamma-Ray Spectrometer on the Solar Maximum Mission satellite has recorded high energy gamma-ray and neutron emission from the flare on 3 June 1982. During the 65 sec. impulsive phase the gamma rays > 10 MeV contains emissions from both primary electron bremsstrahlung and nuclear pion decay. Hence the impulsive phase acceleration process must produce both primary electrons with energies > 60 MeV and ions >500 MeV. This flare also has a extended emission phase lasting more than 1000 sec which is most easily observed at gamma-ray energies > 10 MeV. After removing the counting rates from the more slowly moving neutrons produced at earlier times, the resulting gamma ray spectrum can be entirely explained by nuclear pion production. We find that >70 % of the pions were produced in the extended emission phase. In contrast, more than 70 % of the high energy primary electron bremsstrahlung and the < 30 MeV ion produced nuclear line emission occured in the 65 sec impulsive phase. This represents the first clear observation of a new acceleration process which produces a electron deficient, very hard ion spectrum extending beyond 1000 MeV.