Examining EMIC wave spectral properties using in situ measurements of multi-ion species and hybrid simulations

Thursday, 18 December 2014
Kyungguk Min, Auburn University, Auburn, AL, United States, Kaijun Liu, Auburn University at Montgomery, Auburn, AL, United States, Harlan E. Spence, University of New Hampshire Main Campus, Durham, NH, United States, Geoffrey D Reeves, Los Alamos National Laboratory, Los Alamos, NM, United States, Herbert O Funsten, Los Alamos Natl Laboratory, Los Alamos, NM, United States, Brian Larsen, Los Alamos Natl Lab, Los Alamos, NM, United States, Craig Kletzing, University of Iowa, Iowa City, IA, United States, George B Hospodarsky, Univ Iowa, Iowa City, IA, United States, William S Kurth, University of Iowa, Physics and Astronomy, Iowa City, IA, United States, Richard Eugene Denton, Dartmouth College, Hanover, NH, United States, John R Wygant, University of Minnesota Twin Cities, Minneapolis, MN, United States, John W Bonnell, University of California Berkeley, Berkeley, CA, United States, Aaron W Breneman, The University of Minnesota, Minneapolis, MN, United States and Jörg-Micha Jahn, Southwest Research Inst, San Antonio, TX, United States
Electromagnetic Ion Cyclotron (EMIC) waves are an integral component of the magnetospheric plasma within the Earth's magnetosphere and are suggested, at times, to be the dominant contributor to rapid radiation belt electron loss. This paper presents one EMIC wave event observed by the Van Allen Probes, where strong He-band waves occurred in the high density structure at the edge of the plasmasphere. We extract the simultaneously measured distributions of multi-ion species and examine the wave spectral properties developed under the realistic plasma conditions by carrying out hybrid simulations. The goal is to examine (1) whether the observed waves can be reproduced, (2) how the wave properties are related to the observed plasma parameters, and (3) whether these waves are capable of resonant interacting with geophysically interesting radiation belt electrons. The preliminary result suggests that the observed distribution is indeed unstable and the waves can develop strongest in the He-band.