Solar Energetic Proton Fluxes in Near-Earth Space on March 13–23, 2023

Abstract

The results of studying the fluxes of solar protons with energies greater than 5 MeV in near-Earth space on March 13–23, 2023, are presented. The features of the period under study are no visible solar flare with which the beginning of the event could be associated and an untypical time profile of proton fluxes, as well as a long duration of the existence of solar proton fluxes in near-Earth space. An attempt was made to explain the sources of the observed different variations in particle fluxes and to understand what happened on the Sun and in the near-Earth space. The source of solar protons on March 13, 2023, was an explosive process on the back side of the Sun from the Earth, registered as a coronal mass ejection of very high power. The reason for the long and complex time profile of solar protons was the contribution of particle acceleration processes on the Sun and in the interplanetary medium, as well as the modulation of particle fluxes by the structures of the interplanetary magnetic field. A possible scenario has been proposed to explain the existence of increased fluxes of solar particles on March 15–23, 2023: the formation of a heliospheric structure, this being a closed trap region formed by two interplanetary coronal mass ejections and regions of interaction of high-speed and slow solar wind streams. The study uses experimental data obtained from the Solar Orbiter spacecraft and from spacecraft located near the L1 point of the Earth–Sun system (ACE and DSCOVR) and in geostationary orbit (GOES-16).