Diverse properties of electron Forbush decreases revealed by the Dark Matter Particle Explorer

TL;DR

This study analyzes electron Forbush decreases observed by the Dark Matter Particle Explorer, revealing diverse properties and energy-dependent behaviors linked to interplanetary disturbances caused by solar activity.

Contribution

It provides the first detailed analysis of electron FDs across multiple energies, highlighting their diverse recovery behaviors and potential links to CME geometry.

Findings

Maximum decrease amplitudes range from 15% to 30%.

Recovery times show diverse energy dependence, some constant, some variable.

Diverse behaviors are related to CME velocity, spread, and ejection direction.

Abstract

The Forbush decrease (FD) of cosmic rays is an important probe of the interplanetary environment disturbed by solar activities. In this work, we study the properties of 8 FDs electrons (including positrons) between 2 GeV and 20 GeV from January, 2016 to March, 2024, with the Dark Matter Particle Explorer. The maximum decrease amplitudes of these events are about 30% - 15%, and the amplitudes reduce with energy. The recovery time of these events shows diverse behaviors of their energy-dependence. Some of them show strong energy-dependence, while some have a nearly constant recovery time. It has been shown that such diverse behaviors could be related with the geometry of the disturbed regions of the interplanetary space by coronal mass ejections (CME), represented by the combined effect of the CME velocity, angular spread, and ejection direction.