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Magnetic signatures of plasma interaction and induction at Callisto: The Galileo C21, C22, C23, and C30 flybys

Liuzzo, L. and Simon, S. and Feyerabend, M. and Motschmann, U. (2017) Magnetic signatures of plasma interaction and induction at Callisto: The Galileo C21, C22, C23, and C30 flybys. JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 122, pp. 7364-7386. Wiley. DOI: 10.1002/2017JA024303 ISSN 2169-9380

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Official URL: https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2017JA024303

Abstract

We apply a combination of analytical modeling, hybrid simulations, and data analysis techniques to provide a comprehensive study of magnetometer data from four Galileo flybys of Callisto (C21, C22, C23, and C30) that have never been discussed in the literature before. Callisto’s distance to the center of Jupiter’s magnetospheric current sheet varied considerably from flyby to flyby. Therefore, the relative strength of the magnetic field perturbations due to Callisto’s plasma interaction with Jupiter’s magnetosphere and induction within Callisto’s subsurface ocean drastically changed as well. During C21, a strong magnetic field perturbation along the corotation direction was detected in Callisto’s geometric plasma shadow. This enhancement can be explained with Callisto’s steady state plasma interaction only, if the upstream flow possessed a nonnegligible component away from Jupiter. During C22, Galileo only grazed Callisto’s Alfvén wings which were elevated out of the flyby plane due to the ambient magnetospheric field orientation. During C23, the combination of an inclined flyby trajectory and finite gyroradius effects caused Callisto’s observed Alfvén wings to be slightly asymmetric between both hemispheres. During C30, a discontinuity with a surface normal pointed toward Jupiter was detected within Callisto’s geometric plasma shadow, similar to the earlier C10 flyby. Due to strong plasma interaction and an unfavorable flyby geometry (C21), a large closest approach altitude (C22), or weak inducing field (C23 and C30), no discernible induction signatures were observed during these four flybys. Based on data from all available Galileo flybys, we determine requirements on future flyby geometries that must be satisfied for an identification of Callisto’s subsurface ocean in magnetometer data.

Item URL in elib:https://elib.dlr.de/116099/
Document Type:Article
Title:Magnetic signatures of plasma interaction and induction at Callisto: The Galileo C21, C22, C23, and C30 flybys
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Liuzzo, L.school of earth and atmospheric sciences, georgia institute of technology, atlanta, usaUNSPECIFIED
Simon, S.tu braunschweigUNSPECIFIED
Feyerabend, M.feyerabend (at) geo.uni-koeln.deUNSPECIFIED
Motschmann, U.uwe.motschmann (at) dlr.deUNSPECIFIED
Date:2017
Journal or Publication Title:JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:Yes
Volume:122
DOI :10.1002/2017JA024303
Page Range:pp. 7364-7386
Publisher:Wiley
ISSN:2169-9380
Status:Published
Keywords:Callisto, Galileo magenitc field, modeling, hybrid simulations, subsurface ocean
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Science and Exploration
DLR - Research area:Raumfahrt
DLR - Program:R EW - Erforschung des Weltraums
DLR - Research theme (Project):R - Vorhaben Exploration des Sonnensystems
Location: Berlin-Adlershof
Institutes and Institutions:Institute of Planetary Research > Asteroids and Comets
Deposited By: Schubert, Renate
Deposited On:27 Nov 2017 10:16
Last Modified:31 Jul 2019 20:13

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