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arXiv · 2609.34758

The precipitation of protons and electrons in Jupiter's auroral regions: a statistical comparison based on Juno/JEDI data

B. Benmahi·N. André·V. Hue·Z. -Y. Liu·G. Gronoff·B. Mauk·B. Bonfond·T. Stallard·M. Blanc·M. Devinat·M. Barthélémy
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Abstract

Energetic electrons dominate the energy precipitated into Jupiter's auroral regions, but protons precipitate along the same field lines, with a contribution that remains poorly constrained. We statistically compare the precipitating energy flux of protons and electrons in two of Jupiter's auroral sub-regions, the polar (PE) and main (ME) emission regions. We use Juno/JEDI data from PJ3 to PJ66. The magnetic footprint of the spacecraft, computed with the JRM33 and CON2020 field models, is assigned to one of the two sub-regions, and the precipitating energy flux of each species is obtained by integrating over the loss cone the mean differential intensity measured within it. In both sub-regions, the median proton energy flux is 52 to 223 times lower than that of the electrons, and the total precipitated proton power is less than 2% of the electron power. Proton fluxes are broadly distributed across the sub-regions, with higher values in the ME than in the PE. Protons play a secondary role in Jupiter's auroral energy budget, radiating an estimated 5 to 9 GW in the UV per sub-region, pending a dedicated proton transport modelling. Their Doppler signature in the red wing of the Lyman-$α$ line, undetected by HST and difficult to access with Juno/UVS, is a key observable for the upcoming Juice and Europa Clipper missions.

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B. Benmahi, N. André, V. Hue, Z. -Y. Liu, G. Gronoff, B. Mauk, B. Bonfond, T. Stallard, M. Blanc, M. Devinat, M. Barthélémy. 2026-09-28. The precipitation of protons and electrons in Jupiter's auroral regions: a statistical comparison based on Juno/JEDI data. https://arxiv.org/abs/2609.34758

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