Available on ORBi since
21 January 2020
Article (Scientific journals)
Proton Acceleration by Io's Alfvénic Interaction
Szalay, J. R.; Bagenal, F.; Allegrini, F. et al.
2020 • In Journal of Geophysical Research. Space Physics, 125 (1), p. 2019JA027314
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Keywords :
Juno; aurora; JADE; Io footprint; protons
Abstract :
[en] The Jovian Auroral Distributions Experiment aboard Juno observed accelerated proton populations connected to Io's footprint tail aurora. While accelerated electron populations have been previously linked with Io's auroral footprint tail aurora, we present new evidence for proton acceleration due to Io's Alfvénic interaction with Jupiter's magnetosphere. Separate populations were accelerated above the Io torus and at high latitudes near Jupiter. The timing suggests the acceleration is due to Alfvén waves associated with Io's Main Alfvén Wing. The inferred high-latitude proton acceleration region spans 0.92.5 Jovian radii in altitude, comparable to the expected location for electron acceleration, and suggests the associated Alfvén waves are able to accelerate electrons and protons in similar locations. The proton populations magnetically connected to Io's orbit are recently perturbed, equilibrating with the nominal torus plasma population on a timescale smaller than Io's System III orbital period of 13 h, likely due to wave-particle interactions. The tail populations are split into a wake-like structure with distinct inner and outer regions, where the inner region maps to an equatorial width nearly identical to the diameter of Io. The approximately symmetric surrounding outer regions are each slightly smaller than the central region and may be related to Io's atmospheric extent. The nominal, corotational torus proton population exhibits energization throughout all regions, peaking at the anti-Jovian flank of the inner core region mapping to Io's diameter. These proton observations suggest Alfvén waves are capable of accelerating protons in multiple locations and provide further evidence that Io's Alfvénic interaction is bifurcated.
Research center :
STAR - Space sciences, Technologies and Astrophysics Research - ULiège
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Szalay, J. R.
Bagenal, F.
Allegrini, F.
Bonfond, Bertrand  ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Labo de physique atmosphérique et planétaire (LPAP)
Clark, G.
Connerney, J. E. P.
Crary, F.
Ebert, R. W.
Ergun, R. E.
Gershman, D. J.
Hinton, P. C.
Imai, M.
Janser, S.
McComas, D. J.
Paranicas, C.
Saur, J.
Sulaiman, A. H.
Thomsen, M. F.
Wilson, R. J.
Bolton, S.
Levin, S. M.
More authors (11 more) Less
Language :
Title :
Proton Acceleration by Io's Alfvénic Interaction
Publication date :
Journal title :
Journal of Geophysical Research. Space Physics
Publisher :
Wiley, Hoboken, United States - New Jersey
Volume :
Issue :
Pages :
Peer reviewed :
Peer Reviewed verified by ORBi
Funders :
F.R.S.-FNRS - Fonds de la Recherche Scientifique
Service Public Fédéral de Programmation Politique scientifique (Belspo) - SPF Programmation Politique scientifique (Belspo)


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