Premium
Ganymede‐Induced Decametric Radio Emission: In Situ Observations and Measurements by Juno
Author(s) -
Louis C. K.,
Louarn P.,
Allegrini F.,
Kurth W. S.,
Szalay J. R.
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl090021
Subject(s) - physics , jupiter (rocket family) , radio wave , spacecraft , magnetic field , astronomy , orbiter , radio telescope , galilean moons , astrophysics , solar system , natural satellite , quantum mechanics
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 magnetic field lines connected to Ganymede's tail. Using electromagnetic waves (Juno/Waves) and in situ electron measurements (Juno/JADE‐E), we estimate the radio source size of ∼ 250 km, a radio emission growth rate >3 × 10 −4 , a resonant electron population of energy E = 4 –15 keV and an emission beaming angle of θ = 76–83°, at a frequency ∼ 1.005–1.021 × f c e . We also confirmed that radio emission is associated with Ganymede's downtail far ultraviolet emission.