Evidence for injection of relativistic electrons into the Earth's outer radiation belt via intense substorm electric fields

Lei Dai, John R. Wygant, Cynthia A. Cattell, Scott Thaller, Kris Kersten, Aaron Breneman, Xiangwei Tang, Reiner H. Friedel, Seth G. Claudepierre, Xin Tao

Research output: Contribution to journalArticlepeer-review

45 Scopus citations

Abstract

Observation and model results accumulated in the last decade indicate that substorms can promptly inject relativistic 'killer' electrons (≥MeV) in addition to 10-100 keV subrelativistic populations. Using measurements from Cluster, Polar, LANL, and GOES satellites near the midnight sector, we show in two events that intense electric fields, as large as 20 mV/m, associated with substorm dipolarization are associated with injections of relativistic electrons into the outer radiation belt. Enhancements of hundreds of keV electrons at dipolarization in the magnetotail can account for the injected MeV electrons through earthward transport. These observations provide evidence that substorm electric fields inject relativistic electrons by transporting magnetotail electrons into the outer radiation belt. In these two events, injected relativistic electrons dominated the substorm timescale enhancement of MeV electrons as observed at geosynchronous orbit. Key Points Intense substorm electric fields inject relativistic electrons into radiation belts

Original languageEnglish (US)
Pages (from-to)1133-1141
Number of pages9
JournalGeophysical Research Letters
Volume41
Issue number4
DOIs
StatePublished - Feb 28 2014

Keywords

  • radiation belt relativistic electrons
  • substorm dipolarization
  • substorm electric fields
  • substorm injection

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