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

[PPS01-13] Volcanic Control of Jupiter's Aurora and Middle Magnetosphere Dynamics Observed by Hisaki/EXCEED

*垰 千尋¹、木村 智樹²、土屋 史紀³、村上 豪⁴、吉岡 和夫⁵、山崎 敦⁴、Badman Sarah⁶、三澤 浩昭³、北 元³、笠羽 康正³、吉川 一朗⁵、藤本 正樹⁴ (1.情報通信研究機構、2.理化学研究所、3.東北大学、4.宇宙航空研究開発機構 宇宙科学研究所、5.東京大学、6.Lancaster University)

キーワード：ひさき、木星、オーロラ

Temporal variation of Jupiter's northern aurora during enhanced Io volcanic activity was detected using the EXCEED spectrometer on board the Hisaki Earth-orbiting planetary space telescope. It was found that in association with reported Io volcanic events in early 2015, auroral power and estimated field-aligned currents were enhanced during day of year 40–120. Furthermore, the far ultraviolet color ratio decreased during the event, indicating a decrease of auroral electron mean energy and total acceleration by <30%. During the episode of enhanced Io volcanic activity, Jupiter's magnetosphere contains more source current via increased suprathermal plasma density by up to 42%; therefore, it would have required correspondingly less electron acceleration to maintain the enhanced field-aligned current and corotation enforcement current. Sporadic large enhancements in auroral emission detected more frequently during the active period could have been contributed by non-adiabatic magnetospheric energization.