Io and Ganymede-induced decametric emission: in-situ measurements by Juno

Abstract:

At Jupiter, part of the auroral radio emissions are controlled by the Galilean moons Io, Europa and Ganymede. Until now, they have been remotely detected, using ground-based radio-telescope, or electric antenna aboard spacecraft. The polar trajectory of the Juno orbiter leads to cross the magnetic flux tube connected to these moons, or their tail, and gives a direct in-situ measurements of the characteristics of these decametric moon induced radio emissions (such as the electron population, size of the source, and beaming angle and growth rate of the emission). In this study, we focus on the crossing of the Io and Ganymede flux tube. The study of Juno/JADE-E and Juno/Waves data leads to an estimation of the source size, the resonant electron population energy and the emission beaming angle, and brings us new constrains on the Cyclotron Maser Instability process.