Juno-Derived Electron Density Profiles of the High-Latitude Jovian Ionosphere

Abstract

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. This paper presents derived electron density profiles from four such occultations. Seven profiles, four ingress and three egress, all sample the dawn limb but at a range of magnetic latitudes, including an ingress profile within $5^o$ of the main oval that is consistent with a response to high-energy electron influx. These profiles demonstrate variability in peak densities, peak altitude, and even the number of layers present. This high level of variability in Jupiter's high-latitude ionosphere suggests a complex network of current closure with high temporal variability.