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

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TitleEvolution and slow decay of an unusual narrow ring of relativistic electrons near L ~ 3.2 following the September 2012 magnetic storm
Publication TypeJournal Article
Year of Publication2013
AuthorsThorne, 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
JournalGeophysical Research Letters
Date Published06/2013
KeywordsRBSP; Van Allen Probes
AbstractA 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.
URLhttp://onlinelibrary.wiley.com/doi/10.1002/grl.50627/full
DOI10.1002/grl.50627
Short TitleGeophys. Res. Lett.


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