[P-PS01] Outer Solar System Exploration Today, and Tomorrow

[PPS01-15] Response of Jupiter's Aurora to Mass Loading Monitored by Hisaki During Volcanic Eruptions at Io

*木村 智樹¹、平木 康隆²、垰 千尋³、土屋 史紀⁴、Peter Delamere⁵、吉岡 和夫⁶、村上 豪⁷、山崎 敦⁷、北 元⁴、Badman Sarah⁸、深沢 圭一郎⁹、吉川 一朗⁶、藤本 正樹^7,10 (1.東北大学学際科学フロンティア研究所、2.Advanced Knowledge Laboratory、3.情報通信研究機構、4.東北大学惑星プラズマ・大気研究センター、5.アラスカ大学フェアバンクス校、6.東京大学複雑理工、7.JAXA宇宙科学研究所、8.ランカスター大学物理学部、9.京都大学学術情報メディアセンター、10.東京工業大学地球生命研究所)

キーワード：木星、プラズマ、輸送

The production and transport of plasma mass are essential processes in the dynamics of planetary magnetospheres. At Jupiter, it is hypothesized that Io’s volcanic plasma carried out of the plasma torus is transported radially outward in the rotating magnetosphere and is recurrently ejected as plasmoid via tail reconnection. The plasmoid ejection is likely associated with particle energization, radial plasma flow, and transient auroral emissions. However, it has not been demonstrated that plasmoid ejection is sensitive to mass loading because of the lack of simultaneous observations of both processes. We report the response of plasmoid ejection to mass loading during large volcanic eruptions at Io in 2015. Response of the transient aurora to the mass loading rate was investigated based on a combination of Hisaki satellite monitoring and a newly-developed analytic model. We found the transient aurora frequently recurred at a 2–6-day period in response to a mass loading increase from 0.3 to 0.5 ton/s. In general the recurrence of the transient aurora was not significantly correlated with the solar wind although there was an exceptional event with a maximum emission power of ~10 TW after the solar wind shock arrival. The recurrence of plasmoid ejection requires the precondition that amount comparable to the total mass of magnetosphere, ~1.5 Mton, is accumulated in the magnetosphere. A plasmoid mass of more than 0.1 Mton is necessary in case that the plasmoid ejection is the only process for mass release.