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

¹ Laboratory for Planetary and Atmospheric Physics, University of Liège, Liège, Belgium
² Aix-Marseille Université, CNRS, CNES, Institut Origines, LAM, Marseille, France
³ Institute of Geophysics and Meteorology, University of Cologne, Cologne, Germany
⁴ Institute for Space Astrophysics and Planetology, National Institute for Astrophysics (INAF-IAPS), Rome, Italy
⁵ Southwest Research Institute, San Antonio, TX, USA
⁶ Physics and Astronomy Department, University of Texas at San Antonio, TX, USA
⁷ Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France

^★ Corresponding author: guillaume.sicorello@uliege.be

Received: 30 June 2025
Accepted: 5 September 2025

Abstract

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.