Yao, ZH;
Radioti, A;
Grodent, D;
Ray, LC;
Palmaerts, B;
Sergis, N;
Dialynas, K;
... Dougherty, MK; + view all
(2018)
Recurrent Magnetic Dipolarization at Saturn: Revealed by Cassini.
Journal of Geophysical Research: Space Physics
, 123
(10)
pp. 8502-8517.
10.1029/2018JA025837.
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Abstract
Planetary magnetospheres receive plasma and energy from the Sun or moons of planets and consequently stretch magnetic field lines. The process may last for varied timescales at different planets. From time to time, energy is rapidly released in the magnetosphere and subsequently precipitated into the ionosphere and upper atmosphere. Usually, this energy dissipation is associated with magnetic dipolarization in the magnetosphere.This process is accompanied by plasma acceleration and field‐aligned current formation, and subsequently auroral emissions are often significantly enhanced. Using measurements from multiple instruments on board the Cassini spacecraft, we reveal that magnetic dipolarization events at Saturn could reoccur after one planetary rotation and name them as recurrent dipolarizations. Three events are presented, including one from the dayside magnetosphere, which has no known precedent with terrestrial magnetospheric observations. During these events, recurrent energizations of plasma (electrons or ions) were also detected, which clearly demonstrate that these processes shall not be simply attributed to modulation of planetary periodic oscillation, although we do not exclude the possibility that the planetary periodic oscillation may modulate other processes (e.g., magnetic reconnection) which energizes particles. We discuss the potential physical mechanisms for generating the recurrent dipolarization process in a comprehensive view, including aurora and energetic neutral atom emissions.
| Type: | Article |
|---|---|
| Title: | Recurrent Magnetic Dipolarization at Saturn: Revealed by Cassini |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1029/2018JA025837 |
| Publisher version: | https://doi.org/10.1029/2018JA025837 |
| Language: | English |
| Additional information: | © 2018. The Authors. This is an open access article under the terms of the Creative Commons (https://creativecommons.org/licenses/by/3.0/). |
| Keywords: | dipolarization, magnetosphere, aurora, Cassini, Saturn, field‐aligned current |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10061424 |
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