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Ganymede–induced decametric radio emission: in-situ observations and measurements by Juno
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  • Corentin Kenelm LOUIS,
  • Philippe Louarn,
  • Frederic Allegrini,
  • William S Kurth,
  • Jamey R. Szalay
Corentin Kenelm LOUIS

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Philippe Louarn
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Frederic Allegrini
Southwest Research Institute
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William S Kurth
University of Iowa
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Jamey R. Szalay
Princeton University
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At Jupiter, part of the auroral radio emissions are induced by the Galilean moons Io, Europa and Ganymede. Until now, they have been 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 magnetic flux tubes connected to these moons, or their tail, and gives a direct measure of the characteristics of these decametric moon–induced radio emissions. In this study, we focus on the detection of a radio emission during the crossing of the Ganymede flux tube. Using electromagnetic waves (Juno/Waves) and in-situ electron measurements (Juno/JADE-E), we estimate the flux tube width to be a few 100 km, a growth rate of the radio emission >3x10-4, an electron population of energy E=4-15 keV and an emission beaming angle of θ=76°-83°, at a frequency 1.005-1.021xfce. We also confirmed that radio emission is associated with Ganymede’s down-tail far-ultraviolet emission.
28 Oct 2020Published in Geophysical Research Letters volume 47 issue 20. 10.1029/2020GL090021