Japan Geoscience Union Meeting 2018

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[EE] Poster

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

[P-EM15] Dynamics in magnetosphere and ionosphere

Mon. May 21, 2018 3:30 PM - 5:00 PM Poster Hall (International Exhibition Hall7, 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)

[PEM15-P06] Plasma flow enhancements preceding a large-scale moving cusp aurora

*Yunosuke Nagafusa1, Satoshi Taguchi1, Yasunobu Ogawa2, Keisuke Hosokawa3 (1.Graduate School of Science, Kyoto University, 2.National Institute of Polar Research, 3.Department of Communication Engineering and Informatics, University of Electro-Communications)

Keywords:Plasma flow, cusp, aurora, polar cap

Plasma flow associated with a small-scale poleward moving cusp aurora shows a twin vortex pattern. For a large-scale moving cusp aurora, whose longitudinal width is 2 - 3 hours MLT, however, plasma flow features surrounding the aurora are still unclear. In this study, we present the result from simultaneous observations of the EISCAT Svalbard Radar (ESR) with 32-m steerable and 42-m field-aligned fixed antennas, and a nearby all-sky imager for a large-scale moving cusp aurora event obtained on 8 December, 2013. The result shows that plasma flow enhancements precede the large-scale moving cusp aurora. In other words, the large-scale moving cusp aurora is not created at the forefront of the enhanced plasma flow region. The result also indicates that the forward boundary of the enhanced plasma flow is located nearly perpendicular to the poleward boundary of the moving cusp aurora. We discuss a plausible mechanism of the formation of this boundary.