Multi-interferometric Investigation of Outer Planets Magneto-bremsstrahlung Radiation in Support of Planetary Exploration

Abstract

The interaction of the solar wind with planetary magnetic field creates a magnetic cavity called the magnetosphere. Deep inside this magnetic structure, the trapping of 10's of keV up to 10's (100’s) of MeV electrons (ions) forms the radiation belts. Long-lasting radiation belts exist at Jupiter, Saturn, Uranus and Neptune. At Jupiter, the electron belt is the source of a strong magneto-bremsstrahlung emission at frequencies of ~0.05 - 5 GHz. Although the detection of this radio emission presented the first evidence of a harsh radiation environment at Jupiter in the late 1950s, its spatio-temporal variations on different timescales remain unexplained more than 60 years later. We present our on-going multi-frequency investigation of Jupiter's electron-belt emission from multiple interferometers (VLA, NenuFAR, LOFAR, GMRT, MeerKAT, ATCA). We demonstrate how multi-data-set analyses at 0.05 - 10 GHz can reveal the contribution of trans-to-ultra-relativistic electrons trapped in different magnetospheric regions to Jupiter's radio spectrum. We emphasize how our improved understanding of the dynamical response of energetic electrons to magnetospheric and heliospheric environments can provide new interpretations of on-going remote sensing observations at Jupiter, while yielding new information on the radiation environment that JUICE and Europa Clipper will encounter at larger distances. We finally discuss our computational effort to model the electron-belt emission at Saturn, Uranus and Neptune and subsequent implications for future missions at the ice giant planets.