The global statistical response of the outer radiation belt during geomagnetic storms

TitleThe global statistical response of the outer radiation belt during geomagnetic storms
Publication TypeJournal Article
Year of Publication2018
AuthorsMurphy, KR, Watt, CEJ, Mann, IR, I. Rae, J, Sibeck, DG, Boyd, AJ, Forsyth, CF, Turner, DL, Claudepierre, SG, Baker, DN, Spence, HE, Reeves, GD, Blake, JB, Fennell, J
JournalGeophysical Research Letters
Date Published04/2018
KeywordsGeomagnetic storms; magnetospheric dynamics; Radiation belts; Solar Wind‐Magnetosphere Coupling; statistical analysis; Van Allen Probes
AbstractUsing the total radiation belt electron content calculated from Van Allen Probe phase space density (PSD), the time‐dependent and global response of the outer radiation belt during storms is statistically studied. Using PSD reduces the impacts of adiabatic changes in the main phase, allowing a separation of adiabatic and non‐adiabatic effects, and revealing a clear modality and repeatable sequence of events in storm‐time radiation belt electron dynamics. This sequence exhibits an important first adiabatic invariant (μ) dependent behaviour in the seed (150 MeV/G), relativistic (1000 MeV/G), and ultra‐relativistic (4000 MeV/G) populations. The outer radiation belt statistically shows an initial phase dominated by loss followed by a second phase of rapid acceleration, whilst the seed population shows little loss and immediate enhancement. The time sequence of the transition to the acceleration is also strongly μ‐dependent and occurs at low μ first, appearing to be repeatable from storm to storm.
Short TitleGeophys. Res. Lett.

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