Japan Geoscience Union Meeting 2024

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[E] Oral

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

[P-EM13] Dynamics of the Inner Magnetospheric System

Sun. May 26, 2024 9:00 AM - 10:15 AM 105 (International Conference Hall, Makuhari Messe)

convener:Kunihiro Keika(Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo ), Yoshizumi Miyoshi(Institute for Space-Earth Environmental Research, Nagoya University), Theodore E Sarris(Democritus University of Thrace), Evan G Thomas(Dartmouth College), Chairperson:Yikai Hsieh(Reserach Institute for Sustainable Humanosphere, Kyoto University), Kazuhiro Yamamoto(Graduate School of Science, The University of Tokyo), Kunihiro Keika(Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo)


9:00 AM - 9:15 AM

[PEM13-01] Diffuse aurora flashes and black aurora associated with the dayside plasmapause as caused by a solar wind pressure pulse

*Ryuho Kataoka1, Takeshi Sakanoi2, Yoshizumi Miyoshi3, Yoshimasa Tanaka1, Kiyoka Murase1, Akira Kadokura1, Keisuke Hosokawa4, Shigeru Fujita5 (1.National Institute of Polar Research, 2.Tohoku University, 3.Nagoya University, 4.University of Electro-Communications, 5.Institute for Statistical Mathematics)

Keywords:black aurora, plasmapause , chorus waves

We report a new type of black aurora which repeatedly appeared only when the diffuse aurora flashes over the whole sky. The black aurora event was identified in the afternoon sector (1300~1330 UT = 13~13.5 MLT) at Syowa Station in the Arctic during the solar wind pressure pulse event on July 7, 2023. Followings are our interpretation of the appearance of the diffuse flashes and black aurora: The solar wind pressure pulse caused the field line resonance to modulate the nonlinear wave growth of chorus waves around the plasmapause, which can scatter energetic electrons to emit the repeating diffuse aurora flashes propagating poleward across the whole field-of-view. The nonlinear wave growth is correlated with the high density of the energetic electrons, and the suppressed wave growth inside the plasmasphere appear as the black aurora.