Relativistic Electron Precipitation Observations with CALET on the International Space Station

Abstract

The CALorimetric Electron Telescope (CALET) is a high-energy astroparticle physics experiment installed on the International Space Station, and taking data since October 2015. While designed for studying the origin and the propagation of galactic cosmic rays, CALET is also able to provide a continuous monitoring of space-weather phenomena affecting the near-Earth environment, including solar energetic particle and relativistic electron precipitation (REP) events. In this work we present preliminary results of the REP observations made over a ∼4.5 year acquisition time (October 2015 – May 2020), investigating their correlations with the interplanetary and geomagnetic conditions. We also took advantage of a multi-spacecraft study using the twin Van Allen Probe measurements to complement CALET detections in low-Earth orbit, enabling a more complete picture of the global precipitation rates and drivers.