Isolated Solar Cosmic Ray Events Caused by Energetic Storm Particles (ESPs)

Abstract

Based on the catalogs of solar proton events for the 23rd and 24th solar cycles, events were chosenthat lacked a reliable source of particles but were accompanied by interplanetary and geomagnetic disturbances.As a rule, these events involve small proton fluxes that are detected near the Earth. All of the selectedevents occurred during the arrival of shock waves to the Earth, suggesting that they were likely caused by thearrival of energetic storm particles. It has been shown that flares accompanied by coronal mass ejections,which occurred tens of hours before the onset of the increase in particle fluxes in Earth’s orbit, could be thesource of these events. The selected events exhibited several specific features. Only one of them was accompaniedby a single shock front, while the others had two or three shock waves. The time profile of the eventsresembled a structure bounded by two shock fronts, suggesting that the shock waves likely accelerated andconfined the particles within a limited region of space.