Direct Observation of Subrelativistic Electron Precipitation Potentially Driven by EMIC Waves

TitleDirect Observation of Subrelativistic Electron Precipitation Potentially Driven by EMIC Waves
Publication TypeJournal Article
Year of Publication2019
AuthorsCapannolo, L, Li, W, Ma, Q, Chen, L, Shen, X‐C, Spence, HE, Sample, J, Johnson, A, Shumko, M, Klumpar, DM, Redmon, RJ
JournalGeophysical Research Letters
Date Published11/2019
ISSN0094-8276
Keywordselectron precipitation; EMIC waves; FIREBIRD‐II; quasi linear theory; Radiation belts; Van Allen Probes; wave particle interactions
AbstractElectromagnetic 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.
URLhttps://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL084202
DOI10.1029/2019GL084202
Short TitleGeophys. Res. Lett.


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