Unraveling the drivers of the storm time radiation belt response

TitleUnraveling the drivers of the storm time radiation belt response
Publication TypeJournal Article
Year of Publication2015
AuthorsKilpua, EKJ, Hietala, H, Turner, DL, Koskinen, HEJ, Pulkkinen, TI, Rodriguez, JV, Reeves, GD, Claudepierre, SG, Spence, HE
JournalGeophysical Research Letters
Date Published04/2015
Keywordscoronal mass ejections; Magnetic Storms; Radiation belts; solar wind storm drivers; stream interaction regions; Van Allen Probes
AbstractWe present a new framework to study the time evolution and dynamics of the outer Van Allen belt electron fluxes. The framework is entirely based on the large-scale solar wind storm drivers and their substructures. The Van Allen Probe observations, revealing the electron flux behavior throughout the outer belt, are combined with continuous, long-term (over 1.5 solar cycles) geosynchronous orbit data set from GOES and solar wind measurements A superposed epoch analysis, where we normalize the timescales for each substructure (sheath, ejecta, and interface region) allows us to avoid smearing effects and to distinguish the electron flux evolution during various driver structures. We show that the radiation belt response is not random: The electron flux variations are determined by the combined effect of the structured solar wind driver and prestorm electron flux levels. In particular, we find that loss mechanisms dominate during stream interface regions, coronal mass ejection (CME) ejecta, and sheaths while enhancements occur during fast streams trailing the stream interface or the CME.
URLhttp://doi.wiley.com/10.1002/2015GL063542
DOI10.1002/2015GL063542
Short TitleGeophys. Res. Lett.


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