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Source of radio emissions induced by the Galilean moons Io, Europa and Ganymede: in situ measurements by Juno
  • +13
  • Corentin Kenelm Louis,
  • Philippe Louarn,
  • Brieuc Collet,
  • Noé Clément,
  • Sariah Al Saati,
  • Jamey R. Szalay,
  • Vincent Hue,
  • Laurent Lamy,
  • Stavros Kotsiaros,
  • William S Kurth,
  • Caitriona M Jackman,
  • Yuxian Wang,
  • Michel F. Blanc,
  • Frederic Allegrini,
  • John E. P. Connerney,
  • Daniel J Gershman
Corentin Kenelm Louis
Dublin Institute for Advanced Studies (DIAS)

Corresponding Author:[email protected]

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Philippe Louarn
IRAP
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Brieuc Collet
Laboratoire d'Astrophysique de Marseille
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Noé Clément
Institut de Recherche en Astrophysique et Planétologie
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Sariah Al Saati
Institut de Recherche en Astrophysique et Planétologie
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Jamey R. Szalay
Princeton University
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Vincent Hue
Aix-Marseille Université, CNRS, CNES, Institut Origines, LAM
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Laurent Lamy
LESIA, Observatoire de Paris, CNRS, PSL
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Stavros Kotsiaros
DTU SPace
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William S Kurth
University of Iowa
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Caitriona M Jackman
Dublin Institute for Advanced Studies
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Yuxian Wang
National Space Science Center, Chinese Academy of Sciences
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Michel F. Blanc
IRAP, CNRS-UPS-CNES
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Frederic Allegrini
Southwest Research Institute
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John E. P. Connerney
NASA Goddard Space Flight Center
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Daniel J Gershman
NASA Goddard Space Flight Center
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Abstract

At Jupiter, part of the auroral radio emissions are induced by the Galilean moons Io, Europa and Ganymede. Until now, except for Ganymede, they have been only remotely detected, using ground-based radio-telescopes or electric antennas aboard spacecraft. The polar trajectory of the Juno orbiter allows the spacecraft to cross the range of magnetic flux tubes which sustain the various Jupiter-satellite interactions, and in turn to sample in situ the associated radio emission regions. In this study, we focus on the detection and the characterization of radio sources associated with Io, Europa and Ganymede. Using electric wave measurements or radio observations (Juno/Waves), in situ electron measurements (Juno/JADE-E), and magnetic field measurements (Juno/MAG) we demonstrate that the Cyclotron Maser Instability (CMI) driven by a loss-cone electron distribution function is responsible for the encountered radio sources. We confirmed that radio emissions are associated with Main (MAW) or Reflected Alfvén Wing (RAW), but also show that for Europa and Ganymede, induced radio emissions are associated with Transhemispheric Electron Beam (TEB). For each traversed radio source, we determine the latitudinal extension, the CMI-resonant electron energy, and the bandwidth of the emission. We show that the presence of Alfvén perturbations and downward field aligned currents are necessary for the radio emissions to be amplified.
11 Aug 2023Submitted to ESS Open Archive
12 Aug 2023Published in ESS Open Archive