第6回極域科学シンポジウム[OS] 宙空圏11月16日（月）　国立極地研究所 2階 大会議

Akihito Uchida Herbert

Donald Hampton

Ebihara Yusuke

Fukuda Yoko

Hampton Donald

Kataoka Ryuho

Miyoshi Yoshizumi

三好 由純

内田 ヘルベルト陽仁

海老原 祐輔

片岡 龍峰

福田 陽子

National Institute of Polar Research Repository

  オーロラの残像に見られる上部電離圏プラズマの複雑な高速流  内田ヘルベルト陽仁 1、片岡龍峰 2、福田陽子 3、三好由純 4、海老原祐輔 5、Donald Hampton6 1東海大学工学研究科航空宇宙学専攻, 2国立極地研究所, 3東京大学大学院理学系研究科地球惑星科学専攻 4名古屋大学太陽地球環境研究所, 5京都大学生存圏研究所, 6Geophysical Institute, University of Alaska Fairbanks  Complex and fast plasma flow in the topside ionosphere as seen in the afterglow of aurora  Herbert Akihito Uchida1, Ryuho Kataoka2, Yoko Fukuda3, Yoshizumi Miyoshi4, Yusuke Ebihara5,and Donald Hampton5 1Cource of Aeronautics and astronautics, Tokai University, 2National Institute of Polar Research, 3Department of Earth and Planetary Science, University of Tokyo 4Solar-Terrestrial Environment Laboratory, Nagoya University, 5Geophysical Institute, University of Alaska Fairbanks  Afterglow of aurora at 732 nm can be used to track the plasma flow in the topside ionosphere at 300 km altitude (Dahlgren et al., 2009). From ground-based high-speed (50 fps and 200 fps) imaging observations made by Kataoka et al. (2015), we find two interesting afterglow events on January 7 and January 28 2015, in which the speed of the brightest arc is suddenly accelerated within the field-of-view (15 deg by 15 deg). Both events occurred at close timing to the substorm onset. The existence of the afterglow is confirmed at wavelength range of >665 nm, and any contributions from green and red lines are rejected. The life time of the afterglow is an order of 5 s, which is consistent with the expected emissions from metastable O+ ions at 300 km altitude. The motion of afterglow is complex and the maximum speed is more than an order of magnitude faster than those previously reported by Dahlgren et al. (2009). We report the initial results of the optical flow analysis, and discuss the possibility of such a fast and complex plasma flow in the topside ionosphere.    References Dahlgren, H., Ivchenko, N., Lanchester, B.S., Ashrafi, M., Whiter, D., Marklund, G., and Sullivan, J., First direct optical observations of plasma flows using afterglow of O+ in discrete aurora, Journal of Atmospheric and Solar-Terrestrial Physics, 71, 228-238, 2009.  Kataoka, R., Fukuda, Y., Miyoshi, Y., Miyahara, H., Itoya, S., Ebihara, Y., Hampton, D., Dahlgren, H., Whiter, D., and Ivchenko, N., Compound auroral micromorphology: ground-based high-speed imaging, Earth, Planets and Space, 67-23, 2015.  

Complex and fast plasma flow in the topside ionosphere as seen in the afterglow of aurora

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Complex and fast plasma flow in the topside ionosphere as seen in the afterglow of aurora

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