Sub‐MeV Electron Precipitation Driven by EMIC Waves in Plasmaspheric Plumes at High <i>L</i> Shells
Abstract Electromagnetic ion cyclotron (EMIC) waves are known to be efficient for precipitating >1 MeV electrons from the magnetosphere into the upper atmosphere. Despite considerable evidence showing that EMIC‐driven electron precipitation can extend down to sub‐MeV energies, the precise physical mechanism driving sub‐MeV electron precipitation remains an active area of investigation. In this study, we present an electron precipitation event observed by ELFIN CubeSats on 11 January 2022, exclusively at sub‐MeV energy at L ∼ 8–10.5, where trapped MeV electrons were nearly absent. The THEMIS satellites observed conjugate H‐band and He‐band EMIC waves and hiss waves in plasmaspheric plumes near the magnetic equator. Quasi‐linear diffusion results demonstrate that the observed He‐band EMIC waves, with a high ratio of plasma to electron cyclotron frequency, can drive electron precipitation down to ∼400 keV. Our findings suggest that exclusive sub‐MeV precipitation (without concurrent MeV precipitation) can be associated with EMIC waves, especially in the plume region at high L shells.
Authors
- Qianli Ma (ORCID: https://orcid.org/0000-0001-5452-4756)
- Wen Li (ORCID: https://orcid.org/0000-0003-3495-4550)
- Murong Qin (ORCID: https://orcid.org/0000-0002-5770-6261)
- Sheng Huang (ORCID: https://orcid.org/0000-0002-9951-8787)
- Y. Nishimura (ORCID: https://orcid.org/0000-0003-3126-4394)
- Xin An (ORCID: https://orcid.org/0000-0003-2507-8632)
- Longzhi Gan (ORCID: https://orcid.org/0000-0002-8796-638X)
- Luisa Capannolo (ORCID: https://orcid.org/0000-0003-1755-9022)
- Anton Artemyev (ORCID: https://orcid.org/0000-0001-8823-4474)
- Xiaochen Shen (ORCID: https://orcid.org/0000-0003-1743-4262)
- V. Angelopoulos (ORCID: https://orcid.org/0000-0001-7024-1561)
- Miroslav Hanzelka (ORCID: https://orcid.org/0000-0001-9716-5263)
Institutions
- Boston University (US)
- Planetary Science Institute (US)
- University of California, Los Angeles (US)
- Czech Academy of Sciences, Institute of Atmospheric Physics (CZ)
- GFZ Helmholtz Centre for Geosciences (DE)
Publication Details
- Journal
- Journal of Geophysical Research Space Physics
- Published
- 2025-03-01
- DOI
- https://doi.org/10.1029/2025ja033756
- Citations
- 6
- Primary Topic
- Ionosphere and magnetosphere dynamics
- Type
- article
- Field-Weighted Citation Impact
- 6.93
Funders
- National Science Foundation
- National Aeronautics and Space Administration
- Alexander von Humboldt-Stiftung
- Nuclear Safety and Security Commission
- Air Force Office of Scientific Research