Modeling Ion Conic Formation in Io's Auroral Footprint

Energetic ions outflowing from Jupiter's atmosphere was observed during Juno's 12th perijove crossing (PJ12) in the vicinity of Io's auroral footprint and reported by prior studies. It was hypothesized that Wave-Particle Interactions (WPI) with ion cyclotron waves observed coincident with the ion outflow may be responsible for the heating and subsequent outflow. This study uses numerical simulation and data model comparison to test whether ion cyclotron resonant heating is indeed a plausible mechanism to explain the intense ion outflow observed. Our simulations assume that the wave heating is of limited duration due to Io's footprint motion. The simulations are moreover compared to the previously published Jupiter Energetic Particle Detector Instruments (JEDI) observations at high energies, and the lower energy Jovian Auroral Distributions Experiment (JADE) observations that were not previously reported. We find that the ion cyclotron resonant heating mechanism can indeed lead to ion conic formation and strong vertical transport under certain assumptions about the distribution of wave power with altitude. We also find that the ion outflow is energized quickly with very rapid formation of the ion conic distribution. The implications of the intense ion outflow are also examined and it is found that such strong wave heating can lead to a depletion of the topside ionosphere. Heated ions have been observed escaping Jupiter's ionosphere. During Juno's 12th close approach to Jupiter (PJ12), such escaping ions were observed along the magnetic field connecting Jupiter's atmosphere to Io, a connection that is observable as a bright spot just equatorward of Jupiter's aurora. It was hypothesized that wave particle interactions between the ions and waves in the electric field may be responsible for the heating and subsequent outflow. This study uses computer simulations and data model comparison to test whether the hypothesized wave heating is indeed a plausible mechanism to explain the intense ion outflow observed. We find that this mechanism can indeed lead to the observed properties of the ion flow under certain assumptions. We also find that the ions are accelerated quickly and that such strong wave heating and escape can lead to a depletion of ions in the high-altitude ionosphere. Heating of ions by waves is plausible mechanism for explaining strong ion flows above the Io auroral footprint Simulations using information from Juno wave data indicate that the wave power is likely stronger at lower altitudes Intense wave heating has the potential to deplete Jupiter's topside ionosphere