Evidence of Injection Driven Aurora at Jupiter during Juno Perijove 5

Abstract

Injections in Jupiter's magnetosphere are a dynamic process associated with the inward transport of hot plasma, containing ions and electrons with energies into the keV or even MeV. Previous studies have demonstrated a relationship between electron injections observed in Jupiter's equatorial magnetosphere and transient aurora near Jupiter's main emission [e.g. Mauk et al. 2002]. Here, we present observations from several instruments on Juno between ~03:00 to 05:00 UT on DOY 86 2017 that link electron injection signatures observed at high-latitudes to bright UV emissions near Jupiter's main aurora. These injections, observed at magnetic latitudes of ~50oN and jovicentric distances of ~5.5 – 8 jovian radii (1 RJ ~ 71,400 km), were identified by sudden intensity depletions and enhancements in the low ( 50 keV) energy electrons. They are likely connected to several transient UV emission features observed at jovigraphic latitudes of ~55o – 60oN, lasting for tens of minutes, with high color ratios consistent with an energetic electron source. These combined observations allow us to directly compare the measured in-situ properties of electrons associated with injection events (pitch angle distributions, characteristic energy, energy flux) to the remote observations of the UV emissions that they produce