Variation of Jupiter's Aurora Observed by Hisaki/EXCEED: 3. Volcanic Control of Jupiter's Aurora

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 estima...

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Bibliographic Details
Published inGeophysical research letters Vol. 45; no. 1; pp. 71 - 79
Main Authors 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
Format Journal Article
LanguageEnglish
Published Washington John Wiley & Sons, Inc 16.01.2018
Subjects
Acceleration
Activation
aurora
Auroral emissions
Colour
Corotation
Earth
Earth orbits
Electron acceleration
Enforcement
Hisaki
interaction
Io volcanic activity
Jupiter
Jupiter satellites
Magnetosphere
Planet detection
Planetary magnetospheres
Plasma density
Space telescopes
Temporal variations
Volcanic activity
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Summary: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. Key Points Responses of Jupiter's northern aurora spectra to Io volcanic activity were detected using Hisaki/EXCEED long‐term monitoring Decrease of color ratio, that is, auroral electron energy, suggests reduced electron acceleration for the more highly populated magnetosphere Long‐term observation provided the typical value and variances of auroral emission power and electron parameters
ISSN:0094-8276
1944-8007
DOI:10.1002/2017GL075814