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

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. Key Points JADE observed 0.1–100 keV electrons, regions void of these electrons, and regions of penetrating radiation in Jupiter's polar aurora region The electrons consisted of bidirectional beams with broad energies interspersed between upward beams having narrow energy distributions The energy flux of downward electrons shown here ranged from ~0.01 to 5 mW m−2, the upward flux being up to ~100 times larger Plain Language Summary We report on observations of 0.1 ‐ 100 kilo‐electron volt electrons from the Jovian Auroral Distributions Experiment Electron instrument (JADE‐E) on Juno over the region where Jupiter's ultraviolet (UV) polar aurora is produced. The observations show electrons moving both towards and away from Jupiter. These electrons show both broad and narrow energy distributions, suggesting the presence of at least two different acceleration mechanisms. Regions void of these electrons and regions dominated by penetrating radiation were also identified. The energy flux of the electrons moving towards Jupiter was sufficient to produce the weaker UV polar auroral emissions observed at Jupiter but a different source of electrons, likely with higher energies, is required to account for the brighter emissions.