Juno-derived insights to the Alvenic coupling between Jupiter and its magnetosphere

The magnetosphere of Jupiter is an excellent natural laboratory for plasma dynamics due to its strength and internal plasma source. However, a complication in understanding the flow of energy through the system is the closure of the driving current systems within the chaotic high-latitude ionosphere of Jupiter, a region that has been poorly surveyed. The polar orbit of the Juno spacecraft permits for the first time multiple observations of the high- and mid-latitude ionosphere through the radio occultation technique. Presented are electron density profiles derived from a series of such occultations sampling a range of magnetic latitudes, including multiple profiles within 5° of the main oval that are consistent with ionospheric response to high-energy electron influx. Magnetosphere-ionosphere coupling at high latitudes plays a critical role in maintaining energy and momentum balance through the magnetosphere, due to the Pedersen current in the ionosphere providing closure for the Alvénic current loop that accelerates magnetospheric plasma to near co-rotation with the magnetic field. However, the complex nature of the ionosphere near auroral features complicates analysis of these currents, with multiple case studies for MI coupling presented.