Relativistic electron flux comparisons at low and high altitudes with fast time resolution and broad spatial coverage

Analyses are presented for the first high‐time resolution multisatellite study of the spatial and temporal characteristics of a relativistic electron enhancement event with a rapid onset. Measurements of MeV electrons were made from two low‐altitude polar orbiting satellites and three spacecraft at synchronous altitude. The electron fluxes observed by the low‐altitude satellites include precipitating electrons in both the bounce and drift loss cones as well as electrons that are stably trapped, whereas the observations at geosynchronous altitude are dominated by the trapped population. The fluxes of > 1 MeV electrons at low‐satellite altitude over a wide range of L shells tracked very well the fluxes >0.93 MeV at synchronous altitude.