Spatial Distribution and Properties of 0.1–100 keV Electrons in Jupiter's Polar Auroral Region

Abstract

We present observations of 0.1–100 keV electrons from Juno's Jovian Auroral Distributions Experiment Electron instrument over Jupiter's polar auroral region for periods around four Juno perijoves (PJ1, PJ3, PJ4, and PJ5). The observations reveal regions containing magnetic field aligned beams of bidirectional electrons having broad energy distributions interspersed between beams of upward electrons with narrow, peaked energy distributions, regions void of these electrons, and regions dominated by penetrating radiation. The electrons show evidence of acceleration via parallel electric fields (inverted-V structures) and via stochastic processes (bidirectional distributions). The inverted-V structures shown here were observed from ~1.4 to 2.9 RJ and had spatial scales of hundreds to thousands of kilometers along Juno's trajectory. The upward electron energy flux was typically greater than the downward flux, the latter ranging between ~0.01 and 5 mW m−2 for two cases shown here which we estimate could produce ~0.1–50 kR of ultraviolet emission.