Evolution and slow decay of an unusual narrow ring of relativistic electrons near L similar to 3.2 following the September 2012 magnetic storm

Academic Article

Abstract

  • A quantitative analysis is performed on the decay of an unusual ring of relativistic electrons between 3 and 3.5 RE, which was observed by the Relativistic Electron Proton Telescope instrument on the Van Allen probes. The ring formed on 3 September 2012 during the main phase of a magnetic storm due to the partial depletion of the outer radiation belt for L > 3.5, and this remnant belt of relativistic electrons persisted at energies above 2 MeV, exhibiting only slow decay, until it was finally destroyed during another magnetic storm on 1 October. This long‐term stability of the relativistic electron ring was associated with the rapid outward migration and maintenance of the plasmapause to distances greater than L = 4. The remnant ring was thus immune from the dynamic process, which caused rapid rebuilding of the outer radiation belt at L > 4, and was only subject to slow decay due to pitch angle scattering by plasmaspheric hiss on timescales exceeding 10–20 days for electron energies above 3 MeV. At lower energies, the decay is much more rapid, consistent with the absence of a long‐duration electron ring at energies below 2 MeV.
  • Authors

  • Thorne, RM
  • Li, W
  • Ni, B
  • Ma, Q
  • Bortnik, J
  • Baker, DN
  • Spence, HE
  • Reeves, GD
  • Henderson, MG
  • Kletzing, CA
  • Kurth, WS
  • Hospodarsky, GB
  • Turner, D
  • Angelopoulos, V
  • Status

    Publication Date

  • July 28, 2013
  • Published In

    Keywords

  • plasmaspheric hiss
  • relativistic electrons
  • Digital Object Identifier (doi)

    Start Page

  • 3507
  • End Page

  • 3511
  • Volume

  • 40
  • Issue

  • 14