Electron source at the outer boundary of the radiation belts: Storm time case

Abstract

We examine the strength of the electron source at the outer boundary of the radiation belts using multisatellite observations from Time History of Events and Macroscale Interactions during Substorms during one moderate geomagnetic storm. The electron phase space density (PSD) as a function of the first adiabatic invariant for an equatorially mirroring population over a broad energy range is used to determine the source strength. It is found that the source strength from dipolarization at the outer boundary of the radiation belts during this storm period is well above the observed phase space densities of relativistic electrons inside the outer radiation belt, indicating that the inward radial transport can be a potential source of the relativistic electrons within the radiation belts, even in the strong pitch angle diffusion limit.