The Pedersen and Hall conductances in the Jovian polar regions: New maps based on a broadband electron energy distribution

Context. The ionospheric Pedersen and Hall conductances play an important role in understanding the coupling by which angular momentum, energy, and matter are exchanged between the magnetosphere, ionosphere and thermosphere at Jupiter, modifying the composition and temperature of the planet. In the high-latitude regions, the Pedersen and Hall conductances are enhanced by the auroral electron precipitation. Aims. We investigated the effect of a broadband-precipitating electron energy distribution, similar to the observed electron distributions through particle measurements, on the Pedersen and Hall conductance values. The new conductance values were compared to those obtained from previous studies, notably for a mono-energetic distribution. Methods. The broadband-precipitating electron energy distribution was modeled by a kappa distribution, which is used as an input in an electron transport model that computes the vertical density profiles of ionospheric ions. Assuming that the conductivity is mostly governed by the density of H3+ and CH5+, we then evaluated the vertical profiles of the Pedersen and Hall conductivities from the vertical profiles of the ion density. Finally, the Pedersen and Hall conductances were computed by integrating the corresponding conductivities over altitude. Results. The Pedersen and Hall conductance values are globally higher for a broadband electron energy distribution instead of a mono-energetic distribution. In addition, the considered electron collision cross sections and the chosen method for computing the ion production rates can also have significant impacts on the conductance values. The comparison between our results and those deduced from corotation enforcement theory suggests that either a physical mechanism limits the field-aligned currents or the auroral electrons precipitating in the atmosphere are accelerated by processes that are not associated with the field-aligned currents.