Coulomb Energy Losses in the Solar Corona and the Proton Energy Budget in Flares

摘要

It has recently been proposed, on the basis of measurements of the flux in the ~20Ne 1.634 MeV line, that the energy budget for nonthermal protons in solar flares may be significantly larger than previously assumed. The argument is founded on the fact that the 1.634 MeV feature has a (proton) excitation threshold energy significantly lower than that of the C and O lines in the 46 MeV range. Hence the observed enhanced level of emission in the 1.634 MeV line requires a higher flux of low-energy (～1 MeV) protons than would be obtained from a backward extrapolation of the ～10 MeV spectrum using canonical (i.e., modified Bessel function) spectral forms and so a greater overall energy content.