Broadband electrons observed by the DMSP satellites during storm‐time substorms

Abstract

Electrons that have intense broadband spectra are found to precipitate in the equatorward part of the auroral oval. The electrons are observed by the DMSP satellites in association with particular substorms during the main phase of magnetic storms. Electron fluxes are drastically enhanced after the substorm onset at all the energies measured (32 eV to 30 keV) at magnetic latitudes lower than 60° (L < 4). The energy flux of the electrons exceeds 1.0 × 1013 eV cm−2 s−1 sr−1. The intense electron precipitation lasts less than 1 h. These characteristics are significantly different from those seen in the central plasma sheet region. We suggest that an unknown energization mechanism of these electrons exists at the inner part of the plasma sheet at L < 4 during these particular storm‐time substorms.