SM12A-08:
Prompt Energization of Relativistic and Highly Relativistic Electrons during a Substorm Interval
Monday, 15 December 2014: 11:44 AM
John C Foster1, Daniel N. Baker2, Philip John Erickson1, Harlan E. Spence3, John R Wygant4, Craig Kletzing5, William S Kurth5, Yuri Shprits6, Seth G Claudepierre7, Geoffrey D Reeves8 and Scott A Thaller4, (1)MIT Haystack Observatory, Westford, MA, United States, (2)University of Colorado, Laboratory for Atmospheric and Space Physics, Boulder, CO, United States, (3)University of New Hampshire, Durham, NH, United States, (4)University of Minnesota Twin Cities, Minneapolis, MN, United States, (5)Univ. of Iowa, Iowa City, IA, United States, (6)Massachusetts Institute of Technology, Cambridge, MA, United States, (7)Aerospace Corporation Santa Monica, Santa Monica, CA, United States, (8)Los Alamos National Laboratory, Los Alamos, NM, United States
Abstract:
On March 17, 2013, a large magnetic storm significantly depleted the multi-MeV radiation belt. We present multi-instrument observations from the Van Allen Probes spacecraft RBSP-A and RBSP-B at ~6 Re in the midnight sector magnetosphere and from ground based ionospheric sensors during a substorm dipolarization followed by rapid re-energization of multi-MeV electrons. At ~ 5 Re radial distance, a 50% increase in magnetic field magnitude occurred simultaneously with dramatic increases in 100 keV electron fluxes and a 100x increase in VLF wave intensity. The 100 keV electrons and intense VLF waves provide a seed population and energy source for subsequent radiation belt enhancements. During the event, the two Van Allen Probes spacecraft were separated by ~ 1 hr along the same orbital track enabling a <~1-hr temporal specification of the multi-MeV electron re-energization. Assocated with the substorm, highly relativistic (> 2 MeV) electron fluxes increased immediately at L* ~ 4.5, and ultra-relativistic 4.5 MeV electron flux increased >90x at L*=4 in a time interval of 5 hours or less. Although plasmasphere expansion brings the enhanced radiation belt multi-MeV fluxes inside the plasmasphere several hours post-substorm, we localize their prompt re-energization during the event to regions outside the plasmasphere.
