EMIC-Wave Driven Electron Precipitation Observed by CALET on the International Space Station

• Published in: Geophysical research letters Vol. 49; no. 6
• Main Authors: Bruno, A, Blum, L W, Nolfo, G A de, Kataoka, R, Torii, S, Greeley, A D, Kanekal, S G, Ficklin, A W, Guzik, T G, Nakahira, S
• Format: Journal Article
• Language: English
• Published: Goddard Space Flight Center Wiley 28.03.2022; John Wiley & Sons, Inc
• Subjects: Atmospheric precipitations; Conjugates; Cyclotrons; Depletion; Diffusion; Earth orbit; Earth orbits; Electron precipitation; Electrons; EMIC waves; Geomagnetic field; Geomagnetic storms; Geomagnetism; Global radiation; Heat measurement; International Space Station; Ion cyclotron waves; Magnetic storms; Magnetopause; Multinational space ventures; Outer radiation belt; Precipitation; Probes; Radiation; Radiation belts; Relativistic effects; relativistic electron precipitation; Sensors; Space Radiation; Space stations; Storms; Wave measurement; Wave scattering; Radiation Belts; Relativistic Electron Precipitation; Emic Waves
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2021GL097529

We present an analysis of the relativistic electron precipitation (REP) event measured by the CALorimetric Electron Telescope (CALET) experiment on board the International Space Station during a relatively weak geomagnetic storm on 31 December 2016. CALET observations were compared with the measurements of the Van Allen Probes in the near-equatorial plane to investigate the global radiation belt dynamics and the REP drivers. The magnetically conjugate observations from these two missions demonstrate that the significant MeV precipitation directly detected by CALET in low-Earth orbit during a period of radiation belt depletion following the passage of a high-speed stream, was associated with dusk-side electromagnetic ion cyclotron (EMIC) waves. In addition, the combined wave, REP and trapped electron data suggest that the reported radiation belt depletion can be likely ascribed to the concomitant loss effects of EMIC wave scattering driving the atmospheric precipitation, as well as outward radial diffusion associated with magnetopause shadowing.