Plasma Observations During the 7 June 2021 Ganymede Flyby From the Jovian Auroral Distributions Experiment (JADE) on Juno

We report on plasma observations from Juno/Jovian Auroral Distributions Experiment during the Ganymede flyby on 7 June 2021. Juno approached Ganymede from southern latitudes, passed through the wake region, then through its magnetosphere to closest approach (1,046 km from the surface) on the night side, and then back into Jupiter's plasma disk. We describe general plasma properties in the regions explored along the trajectory. We infer that Juno traversed a region of open field lines where one end intercepts Ganymede and the other Jupiter. The observations do not support Juno crossing into the closed field line region. The ion composition near Ganymede is very different than that of the nearby plasma environment. H-2(+) and H-3(+) ions were detected near Ganymede and in the wake region. Low energy (similar to 0.1-1 keV) electrons are enhanced just outside the magnetopause, in the wake (inbound trajectory) and in the magnetopause boundary layer (outbound trajectory).

Automated summary

This study reports on plasma observations made by the Juno/Jovian Auroral Distributions Experiment during the Ganymede flyby on June 7, 2021. The data suggests that Juno traveled through an open field line region instead of a closed field line region while approaching Ganymede. Furthermore, the ion composition near Ganymede differed significantly from the nearby plasma environment, and low-energy electrons were observed to be enhanced at various boundaries of the magnetosphere.