Japan Geoscience Union Meeting 2015

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Symbol P (Space and Planetary Sciences) » P-EM Solar-Terrestrial Sciences, Space Electromagnetism & Space Environment

[P-EM28] Dynamics in magnetosphere and ionosphere

Thu. May 28, 2015 4:15 PM - 6:00 PM 302 (3F)

Convener:*Yoshizumi Miyoshi(Solar-Terrestrial Environement Laboratory, Nagoya University), Hiroshi Hasegawa(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency), Shin'ya Nakano(The Institute of Statistical Mathematics), Yoshimasa Tanaka(National Institute of Polar Research), Tomoaki Hori(Nagoya University Solar Terrestrial Environment Laboratory Geospace Research Center), Chair:Yoshimasa Tanaka(National Institute of Polar Research)

5:00 PM - 5:15 PM

[PEM28-14] Statistical analysis of magnetosonic waves from the Van Allen Probes data

*Koji NOMURA1, Yoshizumi MIYOSHI1, Kunihiro KEIKA1, Masafumi SHOJI1, Naritoshi KITAMURA1, Satoshi KURITA1, Shinobu MACHIDA1, Ondrej Santolik2, Craig Kletzing3 (1.Solar-Terrestrial Environment Laboratory, 2.Institute of Atmospheric Physics AS CR, 3.The University of Iowa)

Keywords:MSW, inner magnetosphere, Van Allen Probes, EMIC

Magnetosonic waves (MSWs) are X mode electromagnetic emissions seen at between the proton cyclotron frequency and the lower hybrid resonant frequency. Their magnetic field fluctuations have a linear polarization. It has been suggested that MSWs can contribute to the acceleration of relativistic electrons in the radiation belts. In this study, we statistically investigate plasmaspheric MSWs using data from the EMFISIS instrument onboard the Van Allen Probes. The MSWs occur at all local times but in this study we observe them mainly on the dayside and during both magnetically quiet and active periods. We also investigate the polarization of MSWs using the spectral matrix. At L<1.5, the polarization of at the lower frequency component of MSWs changes from R-mode to X-mode. At the same location, there are some L-mode waves that may be converted from the R-mode waves below the cross-over frequency. These L-mode waves may contribute to the plasmaspheric EMIC waves deep in the plasmasphere.