Energetic Proton Precipitation in Jupiter’s Inner Magnetosphere Using Juno Observations

Abstract:

Precipitation into the upper atmosphere is one of the main loss processes of energetic protons in Jupiter’s inner magnetosphere; however, a global distribution of these precipitating protons has not been fully evaluated yet. In this study, we use observations from the JEDI instrument onboard the polar-orbiting Juno satellite to evaluate the precipitating energetic proton (10s–100s keV) distributions inside the bounce loss cone, when Juno passes through high magnetic latitudes. The calculated proton flux and characteristic energy of precipitating protons are binned into various M shells (over 5–50) and magnetic local time (MLT) to construct a global map of the energetic proton precipitation. Moreover, using the magnetic field and plasma wave measurements from the Waves and MAG instruments, we evaluate the potential driver of causing energetic proton precipitation. Our results are critical for understanding the energetic proton dynamics in Jupiter’s inner magnetosphere.