Ion Composition and Electron Pitch Angle Variations for Interchange Events in Jupiter's Inner Magnetosphere

M. Devinat; N. André; G. Vinci; M. Blanc; J. R. Szalay; Z.‐Y. Liu; Q. Nénon; E. Penou; P. Louarn; F. Allegrini; R. W. Ebert; P. W. Valek; F. Bagenal; R. J. Wilson; J.‐Z. Wang; W. S. Kurth; B. H. Mauk; Y. Wang; G. A. DiBraccio; J. E. P. Connerney; S. J. Bolton

doi:10.1029/2025GL116114

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Ion Composition and Electron Pitch Angle Variations for Interchange Events in Jupiter's Inner Magnetosphere

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Ion Composition and Electron Pitch Angle Variations for Interchange Events in Jupiter's Inner Magnetosphere

M. Devinat, N. André, G. Vinci, M. Blanc, J. R. Szalay, Z.‐Y. Liu, Q. Nénon, E. Penou, P. Louarn, F. Allegrini, …

Geophysical research letters, Vol.52(20), e2025GL116114

10/28/2025

DOI: 10.1029/2025GL116114

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Abstract

The outward transport of plasma and magnetic fluxes in the gas giant magnetospheres is balanced with a return flow of flux tubes emptied through magnetic reconnection. Evidence of interchange motions between inward and outward moving flux tubes have long been reported around Jupiter and Saturn. Although amply documented at Saturn, the lack of useable low energy plasma data has prevented the analysis of their plasma properties at Jupiter. The Juno data sets allow us to characterize the plasma populations inside nine interchange events at Jupiter between M‐shells 5 and 10. We confirm that they are strongly depleted in heavy ions and low energy protons and electrons, but filled with higher energy protons and electrons. We model the pitch‐angle distribution of trapped electrons through adiabatic transport and estimate that the reported flux tubes were likely isotropic between M‐shells 11 and 35. The observed features bear strong similarities with their Kronian counterparts. The innermost Galilean moon of Jupiter, Io, is the dominant source of plasma in the Jovian system. Jupiter's magnetosphere is filled with plasma that expands from Io into an equatorial plasma disk and spreads out into the magnetosphere. Theoretical descriptions require that this outward flow be balanced by an inward flow to conserve magnetic flux. Thin, localized, flux tubes (regions of space enclosing constant magnetic flux) with enhanced magnetic pressure have long been detected in the Jovian and Kronian magnetospheres and interpreted as agents for the required return circulation, but the previous lack of plasma data at Jupiter has prevented the analysis of their properties. Here we present observations of nine such flux tubes using Juno plasma observations. We confirm their plasma‐depleted nature and trace back their evolution during adiabatic inward transport. The observed features bear strong similarities with their Kronian counterparts. We report multi‐instrument observations from Juno of nine plasma depleted flux tubes between M‐shells 5 and 10 in the Jovian magnetosphere Based on JADE data, we confirm their significant depletion in heavy ions and low energy protons and electrons We estimate the location where the electron distributions of the flux tubes were isotropic using adiabatic transport theory

Details

Title: Subtitle: Ion Composition and Electron Pitch Angle Variations for Interchange Events in Jupiter's Inner Magnetosphere
Creators: M. Devinat - Centre National de la Recherche Scientifique
N. André - Centre National de la Recherche Scientifique
G. Vinci - University of Bologna
M. Blanc - Aix-Marseille Université
J. R. Szalay - Princeton University
Z.‐Y. Liu - Institut de Recherche en Astrophysique et Planétologie
Q. Nénon - Centre National de la Recherche Scientifique
E. Penou - Institut de Recherche en Astrophysique et Planétologie
P. Louarn - Centre National de la Recherche Scientifique
F. Allegrini - Southwest Research Institute
R. W. Ebert - Southwest Research Institute
P. W. Valek - Southwest Research Institute
F. Bagenal - University of Colorado Boulder
R. J. Wilson - Laboratory for Atmospheric and Space Physics
J.‐Z. Wang - University of Colorado Boulder
W. S. Kurth - University of Iowa
B. H. Mauk - Johns Hopkins University Applied Physics Laboratory
Y. Wang - Chinese Academy of Sciences
G. A. DiBraccio - Goddard Space Flight Center
J. E. P. Connerney - Goddard Space Flight Center
S. J. Bolton - The University of Texas at San Antonio
Resource Type: Journal article
Publication Details: Geophysical research letters, Vol.52(20), e2025GL116114
DOI: 10.1029/2025GL116114
ISSN: 0094-8276
eISSN: 1944-8007
Publisher: AMER GEOPHYSICAL UNION
Grant note: Centre National d'Etudes Spatiales
We are grateful to NASA and contributing institutions that have made the Juno mission possible. French authors acknowledge the support of Centre National d'Etudes Spatiales (CNES, France) to the Juno mission. This study has benefited from funding provided by l'Agence Nationale de la Recherche (ANR) under the Generic Call for Proposals 2022 and 2024. The research performed by M.D., N.A., M.B., Q.N. and M.D., N.A., M.B hold as part of the projects FACOM (ANR-22-CE49-0005- 01 ACT and ANR-24-CE30-0324) and CANTALOUPE, respectively. Z.-Y. L. is funded by a CNES postdoctoral fellowship. The work at SwRI was funded by the NASA New Frontiers Program for Juno through contract NNM06AA75C. The work at APL was funded by NASA New Frontiers Program for Juno via subcontract with the Southwest Research Institute. The work at the University of Colorado was supported as a part of NASA's Juno mission funded by NASA through contract 699050X with the Southwest Research Institute. We thank A. Daly for insightful discussions.
Language: English
Date published: 10/28/2025
Academic Unit: Physics and Astronomy
Record Identifier: 9985019140202771

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