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Variation of Jupiter's Aurora Observed by Hisaki/EXCEED: 3. Volcanic Control of Jupiter's Aurora
Author(s) -
Tao Chihiro,
Kimura Tomoki,
Tsuchiya Fuminori,
Muirakami Go,
Yoshioka Kazuo,
Yamazaki Atsushi,
Badman Sarah V.,
Misawa Hiroaki,
Kita Hajime,
Kasaba Yasumasa,
Yoshikawa Ichiro,
Fujimoto Masaki
Publication year - 2018
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl075814
Subject(s) - jupiter (rocket family) , physics , magnetosphere , volcano , ionosphere , atmospheric sciences , astronomy , astrophysics , geophysics , plasma , geology , space exploration , seismology , quantum mechanics
Abstract 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 nonadiabatic magnetospheric energization.