Analysis of EMIC waves in relation to magnetospheric heavy ion density

Thursday, 18 December 2014
Hyomin Kim1, Eun-Hwa Kim2, Jay Johnson2, Dong-Hun Lee3, C. Robert Clauer4, Marc Lessard5, Mark J. Engebretson6 and Zhonghua Xu1, (1)Virginia Polytechnic Institute and State University, Blacksburg, VA, United States, (2)Princeton Plasma Physics Lab, Princeton, NJ, United States, (3)Kyung Hee University, Yongin, South Korea, (4)National Institute of Aerospace, Hampton, VA, United States, (5)University of New Hampshire Main Campus, Durham, NH, United States, (6)Augsburg College, Minneapolis, MN, United States
This study presents observations of EMIC wave events and their relation to heavy ion density in the magnetosphere. It is well known that EMIC waves play an important role in particle acceleration and loss via wave-particle interaction. It is critical to know the ion composition in the plasma with which EMIC waves interact in order to understand wave generation and propagation because it controls ion cyclotron resonance frequencies of EMIC waves. The presence of heavy ions (He+ and O+) causes the wave modes to be more complex with two additional resonance (ion-ion hybrid and Buchsbaum resonances) and polarization changes, making it challenging to analyze wave generation and propagation. In this study, we show wave polarization and Poynting flux using data from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) and Van Allen Probes (VAP) satellites and their ground conjunctions and compare them with the heavy ion density estimated by a wave model.