Japan Geoscience Union Meeting 2019

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[E] Poster

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

[P-EM15] Study of coupling processes in solar-terrestrial system

Thu. May 30, 2019 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall8, Makuhari Messe)

convener:Mamoru Yamamoto(Research Institute for Sustainable Humanosphere, Kyoto University), Yasunobu Ogawa(National Institute of Polar Research), Satonori Nozawa(Institute for Space-Earth Environment Research), Akimasa Yoshikawa(Department of Earth and Planetary Sciences, Kyushu University)

[PEM15-P02] Detached cusp aurora for southward IMF

*Kohei Takasu1, Satoshi Taguchi1, Keisuke Hosokawa2 (1.Department of Geophysics, Graduate School of Science, Kyoto University, 2.Department of Communication Engineering and Informatics, University of Electro-Communications)

Keywords:Aurora, cusp, plasma convection, IMF

A poleward-moving aurora is a typical phenomenon in the dayside cusp of the high-latitude ionosphere. This aurora usually originates near the equatorward boundary of the cusp, and diminishes near the poleward boundary of the persistent cusp auroral emissions. In this study we have examined faint poleward-moving auroras that are detached from the persistent cusp emissions by analyzing 630-nm aurora image data from an all-sky imager at Longyearbyen, Svalbard, and precipitating electron data from DMSP spacecraft. These auroras occur for southward IMF, and are located at latitudes higher than 80 MLAT. The intensities are very weak (less than 1 kilo Rayleigh). The result of the analysis shows that the speed of the auroral motion is 1 to 2 km/s, which is faster than typical convection speed in the dayside polar cap. We show the similarities and differences between the faint aurora and the typical poleward moving cusp aurora, and discuss how soft electron precipitation occurs in the region that is well separated from the cusp.