SM24B-06
Energy ranges and pitch angles of outer radiation belt electrons depleted by an intense dayside hydrogen band EMIC wave event on February 23, 2014
Tuesday, 15 December 2015: 17:15
2018 (Moscone West)
Mark J. Engebretson1, Jennifer L Posch1, Chia-Lin Huang2, Shrikanth G Kanekal3, Mei-Ching Hannah Fok3, Craig J Rodger4, Charles William Smith2, Harlan E. Spence5, Daniel N. Baker6, Craig Kletzing7 and John R Wygant8, (1)Augsburg College, Minneapolis, MN, United States, (2)University of New Hampshire Main Campus, Durham, NH, United States, (3)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (4)University of Otago, Dunedin, New Zealand, (5)University of New Hampshire Main Campus, Space Science Center, Durham, NH, United States, (6)University of Colorado at Boulder, Boulder, CO, United States, (7)University of Iowa, Iowa City, IA, United States, (8)University of Minnesota Twin Cities, Minneapolis, MN, United States
Abstract:
Although most studies of the effect of EMIC waves on relativistic electrons have focused on wave events in the afternoon sector in the outer plasmasphere or plume region, strong magnetospheric compressions provide an additional stimulus for EMIC wave generation across a large range of local times and L shells. We present here observations of the effects of an intense, long-duration hydrogen band EMIC wave event on February 23, 2014 that was stimulated by a gradual 4-hour rise and subsequent sharp increases in solar wind pressure. Large-amplitude linearly polarized hydrogen band EMIC waves (up to 25 nT p-p) that included triggered emissions appeared for over 4 hours at both Van Allen Probes while these spacecraft were outside the plasmapause, in a region with densities ~5-20 cm-3, as they passed near apogee from late morning through local noon. Observations of radiation belt electrons by the REPT and MagEIS instruments on these spacecraft showed that these waves caused significant depletions of more field-aligned electrons at ultrarelativistic energies from 5.2 MeV down to ~2 MeV, and some depletions at energies down to below 1 MeV as well.
