Characteristics of relativistic solar cosmic rays in large ground-level events in 1956–2005

Abstract

The parameters of relativistic solar protons have been obtained and their dynamics has been investigated for 12 large ground-level solar cosmic-ray events that occurred in the period 1956–2005 on the basis of the data of the worldwide network of neutron monitor stations, using an original technique including solution of the inverse problem. It is shown that the flux of relativistic solar protons contains two populations of particles: prompt and delayed, which differ in the energy spectra and pitch-angle distributions and, obviously, originate from different sources on the Sun.