Evolution and slow decay of an unusual narrow ring of relativistic electrons near L ~ 3.2 following the September 2012 magnetic storm
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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DOI：
10.1002/grl.50627
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发表时间：
2013-07
影响因子：
5.2
通讯作者：
R. Thorne;W. Li;Binbin Ni;Q. Ma;J. Bortnik;D. N. Baker;H. Spence;Geoff D. Reeves;M. G. Hender
中科院分区：
文献类型：
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作者：
R. Thorne;W. Li;Binbin Ni;Q. Ma;J. Bortnik;D. N. Baker;H. Spence;Geoff D. Reeves;M. G. Hender
对用相对论电子质子望远镜在Van Allen探测器上观测到的3~3.5Re的反常相对论电子环的衰变进行了定量分析。2012年9月3日，由于L 3.5外辐射带的部分耗尽，在一场磁暴的主阶段形成了这个环，而这个残留的相对论电子带在能量超过2 MeV的情况下持续存在，只表现出缓慢的衰变，直到10月1日的另一场磁暴中最终被摧毁。相对论电子环的这种长期稳定性与等离子体顶层快速向外迁移和维持到L=4以上的距离有关。因此，残余环不受动态过程的影响，动态过程导致L和GT；4的外辐射带迅速重建，并且只有在3 MeV以上的电子能量超过10-20天的时间尺度上，由于等离子体层嘶嘶声的俯仰角散射，才会发生缓慢衰变。在较低的能量下，衰变要快得多，这与能量低于2 MeV时没有持续时间较长的电子环相一致。
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.