Solar flare neutron and accelerated ion angular distributions

The authors made Monte Carlo calculations of the angular and energy distributions of neutrons escaping from the solar atmosphere, expected from thick-target interactions of flare-accelerated ions with a variety of energy spectra and incident angular distributions, ranging from downward beaming to magnetic mirroring. Comparing the calculations with measurements of the neutron flux from the flares of 1980 June 21 at a heliocentric angle of 89° and 1982 June 3 at 72°, the authors found that the bulk of the observed neutron flux was consistent with that expected from neutron production with an essentially δ-function time history following that of the 4 - 7 MeV emission. Both the angular distribution and the energy spectrum of the accelerated ions were determined.