Study of energetic protons associated with interplanetary shocks during the period March-May 1981 using Prognoz-8 data

The passing of 9 interplanetary shocks through the position of the Prognoz-8 spacecraft in March-May 1981 produced different response in energetic protons (Ep≥12 keV). For two shocks the profiles are in agreement with the model of diffusion acceleration. They had the greatest shock strength corresponding to a maximum energy gain in the individual interaction of the protons with the shock front. They corresponded to quasi-parallel shocks initiated by flares with eastern heliolongitudes (≥30E). Two other events with the temporal profile corresponding to shock drift acceleration were caused by flares on the western part of the solar disk (≥30W). The peak flux for the flares with high importance (3B) was higher than that for low importance (1N) if all ''intermediate'' (30W-30E) flares are taken together. For those events the profile of the flux is complex and both acceleration mechanisms could be effective. (author) 6 figs., 1 tab., 17 refs