Dawn‐Dusk Asymmetry of Plasma Flow in Jupiter's Middle Magnetosphere Observed by Juno

Abstract

Abstract Based on plasma observations from Juno's Jovian Auroral Distributions Experiment instrument and forward modeling, we investigate the dawn‐dusk asymmetries within Jupiter's magnetosphere between 10 and 40 RJ. On the dawnside, the flux tubes are depleted characterized by low density and near rigid‐corotation velocity, with a low temperature and thin plasma sheet. On the duskside, the flux tubes are assimilated characterized by high density and sub‐corotation velocity, with a hotter and thicker plasma sheet. Super‐corotating hot inflows originating from reconnection events are identified in the pre‐dawn sector. These observations are consistent with the Vasyliūnas cycle, suggesting it operates in a region closer to Jupiter than previous studies suggested. Outflows are locally coupled with swept‐back magnetic fields and are frequently observed near midnight. Inflows are locally coupled with swept‐forward fields with higher temperatures. The discernible temperature difference between inflows and outflows reveals their distinct origins. Plasma beta increases with radial distance, suggesting increased instabilities at larger distances.

Keywords

• Jupiter
• plasma sheet
• local time
• Juno
• JADE