TY - JOUR
T1 - Source of Radio Emissions Induced by the Galilean Moons Io, Europa and Ganymede
T2 - In Situ Measurements by Juno
AU - Louis, C. K.
AU - Louarn, P.
AU - Collet, B.
AU - Clément, N.
AU - Al Saati, S.
AU - Szalay, J. R.
AU - Hue, V.
AU - Lamy, L.
AU - Kotsiaros, S.
AU - Kurth, W. S.
AU - Jackman, C. M.
AU - Wang, Y.
AU - Blanc, M.
AU - Allegrini, F.
AU - Connerney, J. E.P.
AU - Gershman, D.
N1 - Publisher Copyright:
© 2023. American Geophysical Union. All Rights Reserved.
PY - 2023/12
Y1 - 2023/12
N2 - 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.
AB - 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.
KW - Europa
KW - Galilean moons (Io
KW - Ganymede)
KW - Juno
KW - Jupiter
KW - cyclotron maser instability
KW - radio emission
UR - http://www.scopus.com/inward/record.url?scp=85178887128&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85178887128&partnerID=8YFLogxK
U2 - 10.1029/2023JA031985
DO - 10.1029/2023JA031985
M3 - Article
AN - SCOPUS:85178887128
SN - 2169-9402
VL - 128
JO - Journal of Geophysical Research: Space Physics
JF - Journal of Geophysical Research: Space Physics
IS - 12
M1 - e2023JA031985
ER -