Rights statement: 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
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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - Auroral beads at Saturn and the driving mechanism
T2 - Cassini proximal orbits
AU - Radioti, Aikaterini
AU - Yao, Zhonghua
AU - Grodent, Denis
AU - Palmaerts, B.
AU - Roussos, E.
AU - Dialynas, Kostas
AU - Mitchell, Donald G.
AU - Pu, Z.Y.
AU - Badman, Sarah
AU - Gerard, Jean Claude
AU - Pryor, W.
AU - Bonfond, B. .
N1 - 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
PY - 2019/10/30
Y1 - 2019/10/30
N2 - 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.
AB - 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.
KW - Saturn
KW - aurora
KW - Cassini
KW - plasma instability
U2 - 10.3847/2041-8213/ab4e20
DO - 10.3847/2041-8213/ab4e20
M3 - Journal article
VL - 885
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
SN - 2041-8205
IS - 1
M1 - L16
ER -