Study of Temporal Profile and Flux Variation of GLE Events During Solar Cycles 23 and 24 Using GOES Data

Abstract

A ground level enhancement (GLE) event of solar cosmic rays refers to the sudden, sharp, and short-lived enhancement of energetic particles at ground level generated from a solar flare accompanied by a coronal mass ejection (CME). The study of GLE events not only provides the basis for the research of the origin, propagation, and acceleration of cosmic rays but also has important significance for space-weather research. In this article, we analyzed the temporal profile and flux variation of the electrons, X rays, and protons of 18 GLE events during Solar Cycles 23 and 24 using GOES series spacecraft data. The results suggested that the release time, onset time, peak time, and end time of the GLEs depend upon the energy and species of particles. The release time of protons with higher energies is later than for those with lower energies; the opposite is true for the onset time, peak time, and end time. The rise time decreases with the energy, and the recovery time increases first and then decreases with increasing energy. The energy spectrum of particles at onset time is harder than the peak spectrum. The energy spectrum at onset time is most affected by the CME speed, and the correlation of the peak energy spectrum and the flare longitude is strongest. The acceleration ability of CME-driven shock to low-energy particles is stronger than that of high-energy particles.