Direct Observation of Subrelativistic Electron Precipitation Potentially Driven by EMIC Waves
Abstract
Electromagnetic ion cyclotron (EMIC) waves are known to typically cause electron losses into Earth's upper atmosphere at >~1 MeV, while the minimum energy of electrons subject to efficient EMIC‐driven precipitation loss is unresolved. This letter reports electron precipitation from subrelativistic energies of ~250 keV up to ~1 MeV observed by the Focused Investigations of Relativistic Electron Burst Intensity, Range and Dynamics (FIREBIRD‐II) CubeSats, while two Polar Operational Environmental Satellites (POES) observed proton precipitation nearby. Van Allen Probe A detected EMIC waves (~0.7–2.0 nT) over the similar L shell extent of electron precipitation observed by FIREBIRD‐II, albeit with a ~1.6 magnetic local time (MLT) difference. Although plasmaspheric hiss and magnetosonic waves were also observed, quasi‐linear calculations indicate that EMIC waves were the most efficient in driving the electron precipitation. Quasi‐linear theory predicts efficient precipitation at >0.8–1 MeV (due to H‐band EMIC waves), suggesting that other mechanisms are required to explain the observed subrelativistic electron precipitation.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 25, 2019
- Source ID
- 10.1029/2019gl084202
Entities
People
- Arlo Johnson
- D. M. Klumpar
- Harlan Spence
- John Sample
- Luisa Capannolo
- Lunjin Chen
- Mykhaylo Shumko
- Qianli Ma
- R. J. Redmon
- Wen Li
- X.‐c. Shen
Organizations
- Air Force Office of Scientific Research
- Boston University
- Canada Foundation for Innovation
- Canadian Space Agency
- District of Columbia Space Grant Consortium
- Montana State University
- National Science Foundation
- National Stroke Foundation
- University of Colorado Boulder
- University of New Hampshire
- University of Texas at Dallas