Gerald H Share

Abstract:  . HESSI will provide the high-resolution #-ray spectroscopy not available in early missions. In spite of these spectral limitations the experiments on SMM, Yohkoh, GRANAT and the Compton Gamma Ray Observatory have provided data for fundamental discoveries over the past decades relating to particle acceleration, transport and energetics in flares and to the ambient abundance of the corona and chromosphere. These include: 1) enhancement in the concentration of low FIP elements where accelerated particles interact, 2) a new line ratio for deriving the spectra of accelerated particles # < 10 MeV, 3) energies in accelerated ions that exceed those in electrons for some flares, 4) a highly variable ion to electron ratio during flares, 5) concentration of 3 He in flare-accelerated particles enhanced by a factor of # >1000 over its photospheric value, 6) an accelerated #/p ratio > 0.1 in several flares and evidence for high ambient 4 He in some flares, 7) measurements of the positronium...