Formation of new electron radiation belt during magnetospheric compression event

T. Obara, X. Li

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


The rapid formation of the new electron belts during March 24-28, 1991 magnetic storm was investigated by using Akebono RDM (radiation monitor) observations. Immediately after the storm sudden commencement (SSC) at 03:41 UT on March 24, highly energetic (>2.5MeV) electrons were promptly enhanced deep in the inner magnetosphere, forming a new radiation belt peaked around L=2.6. There was a very big magnetic storm activity around 22 UT on March 24; e.g. AE reached 2300 nT and Dst went down to -300 nT, and the new radiation belt moved further toward the Earth with its peak at L=2.2. Measurements from the Akebono RDM instrument show that plenty of intermediate-energy (0.3-0.95MeV) electrons were supplied in regions around L=2.8 by early March 25. These electrons could be the source populations, forming another radiation belt there. The increase in the intensity of MeV electrons around the peak (L=2.8) was somewhat smooth. It took several days for MeV electrons to reach a saturation level. The prolonged substorm activities during the recovery phase of the magnetic storm got these electrons more energetic. The new radiation belt formed around L=2.2 persisted for almost one year, while the other radiation belt formed around L=2.8 persisted for only one month and half. This difference would be the difference of the loss rate of the MeV electrons in both locations.

Original languageEnglish
Pages (from-to)1027-1032
Number of pages6
JournalAdvances in Space Research
Issue number4
Publication statusPublished - 2003 Jan 1
Externally publishedYes

ASJC Scopus subject areas

  • Aerospace Engineering
  • Astronomy and Astrophysics
  • Geophysics
  • Atmospheric Science
  • Space and Planetary Science
  • Earth and Planetary Sciences(all)


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