Rapid Relativistic Electron Enhancements and Associated Particle Injections: A Multi‐Spacecraft Statistical Study

Abstract

AbstractRapid relativistic electron enhancements (REE) in the outer radiation belt have long been an intriguing phenomenon for space weather. In this study, we investigate rapid REE from October 2012 to December 2017 using multi‐spacecraft observations. A total of 27 rapid REE events are identified from the Van Allen Probes (RBSP) measurements with a 5 times increase of MeV electrons at the center of the outer radiation belt (L = 4.5–5.5) in a half RBSP orbit (∼4.5 hr). All REE events are found to be in association with pulse‐like injections of MeV electrons in the outer radiation belt. Electron fluxes in each injection at L ∼ 6.6 and the overall electron enhancements at L = 4.5–5.5 are quantified. The 500 keV and 0.8–1 MeV electron fluxes are correlated in injections and in overall enhancements. Substorm strength is more intense before/during the REE than intervals after the REE. The statistical study suggests that substorm‐associated MeV electron injections are highly correlated with rapid REE in the outer radiation belt.