Abstract
Electron radiation belts change dramatically over a period ranging from a few seconds to as long as years. It is well known that the energetic electron flux varies during geomagnetic disturbances and that relativistic electrons in the other radiation belt change with solar wind speed. However, electronic direct observation (10 eV-20 MeV) in the field of acceleration has not been realized to date. To investigate the radiation belt, a smallsat Energization and Radiation in Geospace (ERG) is planned. One purpose of the ERG mission is to reveal the acceleration mechanism of high energy particles in the radiation belt. To achieve this, the ERG will observe electrons directly, which are thought to be accelerated to high energy. In the present paper, we introduce the performance of Extremely High-Energy Plasma/Particle sensor for Electrons (XEP-e) and response result of the sensor by GEANT4 simulations.
