Auroral beads at Saturn and the driving mechanism : Cassini proximal orbits

Radioti, Aikaterini and Yao, Zhonghua and Grodent, Denis and Palmaerts, B. and Roussos, E. and Dialynas, Kostas and Mitchell, Donald G. and Pu, Z.Y. and Badman, Sarah and Gerard, Jean Claude and Pryor, W. and Bonfond, B. . (2019) Auroral beads at Saturn and the driving mechanism : Cassini proximal orbits. Astrophysical Journal Letters, 885 (1): L16. ISSN 2041-8205

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During the Grand Finale Phase of Cassini, the Ultraviolet Imaging Spectrograph on board the spacecraft detected repeated detached small-scale auroral structures. We describe these structures as auroral beads, a term introduced in the terrestrial aurora. Those on DOY 232 2017 are observed to extend over a large range of local times, i.e., from 20 LT to 11 LT through midnight. We suggest that the auroral beads are related to plasma instabilities in the magnetosphere, which are often known to generate wavy auroral precipitations. Energetic neutral atom enhancements are observed simultaneously with auroral observations, which are indicative of a heated high pressure plasma region. During the same interval we observe conjugate periodic enhancements of energetic electrons, which are consistent with the hypothesis that a drifting interchange structure passed the spacecraft. Our study indicates that auroral bead structures are common phenomena at Earth and giant planets, which probably demonstrates the existence of similar fundamental magnetospheric processes at these planets.

Item Type:
Journal Article
Journal or Publication Title:
Astrophysical Journal Letters
Additional Information:
This is an author-created, un-copyedited version of an article accepted for publication/published in The Astrophysical Journal Letters. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at doi: 10.3847/2041-8213/ab4e20
Uncontrolled Keywords:
?? saturnauroracassiniplasma instabilityspace and planetary scienceastronomy and astrophysics ??
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Deposited On:
07 Nov 2019 11:35
Last Modified:
31 Dec 2023 01:08