The acceleration and propagation of solar cosmic rays as deduced from the relative abundance of protons to helium nuclei

Abstract

Except for protons, the chemical composition of solar cosmic rays is very similar to the abundance of the elements at the photosphere of the sun. If we consider the relative abundance ratio of protons to a-particles (P/a) at constant rigidity, this ratio is highly variable from one solar cosmic ray event to another. This ratio observed at the earth, The chemical composition and rigidity spectra of solar cosmic rays suggest that solar cosmic rays are mainly accelerated by the Fermi mechanism in solar flares. The jbserved variation of P/a's is produced mainly through the difference between the propagation characteristics of protons and a-particles.