Magnetic Reconnection Near the Planet as a Possible Driver of Jupiter’s Mysterious Polar Auroras

Masters, A., Dunn, W. R., Stallard, Tom, Manners, H. and Stawarz, Julia (2021) Magnetic Reconnection Near the Planet as a Possible Driver of Jupiter’s Mysterious Polar Auroras. Journal of Geophysical Research: Space Physics, 126 (8). e2021JA029544. ISSN 2169-9380

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Auroral emissions have been extensively observed at the Earth, Jupiter, and Saturn. These planets all have appreciable atmospheres and strong magnetic fields, and their auroras predominantly originate from a region encircling each magnetic pole. However, Jupiter’s auroras poleward of these “main” emissions are brighter and more dynamic, and the drivers responsible for much of these mysterious polar auroras have eluded identification to date. We propose that part of the solution may stem from Jupiter’s stronger magnetic field. We model large-scale Alfvénic perturbations propagating through the polar magnetosphere toward Jupiter, showing that the resulting <0.1° deflections of the magnetic field closest to the planet could trigger magnetic reconnection as near as ∼0.2 Jupiter radii above the cloud tops. At Earth and Saturn this physics should be negligible, but reconnection electric field strengths above Jupiter’s poles can approach ∼1 V m−1, typical of the solar corona. We suggest this near-planet reconnection could generate beams of high-energy electrons capable of explaining some of Jupiter’s polar auroras.

Item Type: Article
Additional Information: Funding information: A. Masters and J. Stawarz are supported by Royal Society University Research Fellowships. H. Manners is supported by a Royal Society PhD studentship. W. Dunn is supported by a Science and Technology Facilities Council (STFC) research grant to University College London (UCL) and by Euro-pean Space Agency (ESA) contract no. 4000120752/17/NL/MH
Uncontrolled Keywords: magnetic reconnection, magnetic field, polar aurora, Jupiter
Subjects: F300 Physics
F500 Astronomy
Department: Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User: Rachel Branson
Date Deposited: 07 Dec 2022 15:43
Last Modified: 07 Dec 2022 15:45

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