Comparison of the solar cosmic ray events on May 7, 1978, and November 22, 1977

Abstract

An analysis has been made of the solar cosmic ray events on May 7, 1978, and November 22, 1977, to determine the energy spectra of the solar protons from 50 MeV to 10 GeV, the pitch angle distributions, the intensity‐time profiles, and the anisotropy‐time profiles. Data from neutron monitors and IMP 7 and 8 satellites were used. It is found that the energy spectra of the solar protons obtained from neutron monitors and satellite observations are in good agreement in the overlapping energy range when the pitch angle distribution is taken into account. The energy spectra covering three decades of energy and eight decades of intensity and their time variations were remarkably similar for the two events. The difference in the neutron monitor responses for the events was mainly due to the different pitch angle distributions. For the prompt particle event on May 7, 1978, the shapes of the intensity‐time profiles for various energies are the result of the energy dependence of the time‐extended injection of particles into the interplanetary medium. This event is especially important for the study of the acceleration of solar particles and their subsequent injection into the interplanetary medium. For the November 22, 1977, event, even though the propagation of the solar protons in the IMF was essentially diffusive, the solar particle injection was also observed to be time extended and energy dependent.