Japan Geoscience Union Meeting 2018

Presentation information

[EE] Oral

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

[P-EM15] Dynamics in magnetosphere and ionosphere

Sun. May 20, 2018 3:30 PM - 5:00 PM 303 (3F International Conference Hall, Makuhari Messe)

convener:Yoshimasa Tanaka(National Institute of Polar Research), Tomoaki Hori(Institute for Space-Earth Environmental Research, Nagoya University), Aoi Nakamizo(情報通信研究機構 電磁波研究所, 共同), Mitsunori Ozaki(Faculty of Electrical and Computer Engineering, Institute of Science and Engineering, Kanazawa University), Chairperson:Ebihara Yusuke(RISH, Kyoto University), Hasegawa Hiroshi(Institute of Space and Astronautical Science, JAXA)

4:15 PM - 4:30 PM

[PEM15-22] Spectral characteristics of EMIC waves observed at THEMIS probes in the outer magnetosphere

*Gi-Jeong Kim1, Khan-Hyuk Kim1 (1.Kyung Hee University)

We have statistically examined the properties of EMIC waves observed by THEMIS probes in the outer magnetosphere (L = 6~12) for 2008-2011. The wave events were identified in 3-min intervals through a semiautomated wave selection procedure. Using Fourier spectral analysis for each 3-min segments, we determine the ellipticity, the azimuth orientation angle of the polarization ellipse, and wave normal angle between the wave propagation vector orientation and background field direction. Unlike previous studies, spectral properties are examined for wave events showing high coherence (> 0.7) between two transverse (δBx: radial and δBy: eastward) components (i.e., phase-coherent sinusoidal wave events) because wave polarization characteristics obtained from the spectral analysis are meaningful only in the case of a plane wave. We found that only ~10% of EMIC waves show high coherence. This indicates that most of EMIC waves in the outer magnetosphere are phase-incoherent waves. In this study we compare previous observations and our statistical results. In addition, we also compare the wave normal angles obtained from Fourier analysis and the minimum variance analysis.