Near-Earth Injection of MeV Electrons associated with Intense Dipolarization Electric Fields: Van Allen Probes observations

TitleNear-Earth Injection of MeV Electrons associated with Intense Dipolarization Electric Fields: Van Allen Probes observations
Publication TypeJournal Article
Year of Publication2015
AuthorsDai, L, Wang, C, Duan, S, He, Z, Wygant, JR, Cattell, CA, Tao, X, Su, Z, Kletzing, C, Baker, DN, Li, X, Malaspina, D, J. Blake, B, Fennell, J, Claudepierre, S, Turner, DL, Reeves, GD, Funsten, HO, Spence, HE, Angelopoulos, V, Fruehauff, D, Chen, L, Thaller, S, Breneman, A, Tang, X
JournalGeophysical Research Letters
Date Published07/2015
Keywordselectric fields; radiation belt electrons; substorm dipolarization; substorm injection; Van Allen Probes
AbstractSubstorms generally inject 10s-100s keV electrons, but intense substorm electric fields have been shown to inject MeV electrons as well. An intriguing question is whether such MeV electron injections can populate the outer radiation belt. Here we present observations of a substorm injection of MeV electrons into the inner magnetosphere. In the pre-midnight sector at L∼5.5, Van Allen Probes (RBSP)-A observed a large dipolarization electric field (50mV/m) over ∼40s and a dispersionless injection of electrons up to ∼3 MeV. Pitch angle observations indicated betatron acceleration of MeV electrons at the dipolarization front. Corresponding signals of MeV electron injection were observed at LANL-GEO, THEMIS-D, and GOES at geosynchronous altitude. Through a series of dipolarizations, the injections increased the MeV electron phase space density by one order of magnitude in less than 3 hours in the outer radiation belt (L>4.8). Our observations provide evidence that deep injections can supply significant MeV electrons.
URLhttp://doi.wiley.com/10.1002/2015GL064955
DOI10.1002/2015GL064955
Short TitleGeophys. Res. Lett.


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