Energy distributions of precipitating electrons in Jupiter's auroral regions from combined Juno/JADE and Juno/JEDI measurements
Abstract
Jupiter's auroras are produced by magnetospheric electrons precipitating into its atmosphere. Juno/JADE and Juno/JEDI together measure these electrons from 100 eV to 1 MeV. However, their auroral spectra are poorly reproduced by the widely used kappa distribution, hereafter the classical single-kappa distribution. We aim to statistically characterize the energy flux distributions of precipitating auroral electrons and to derive a new phenomenological 4-kappa distribution better suited to JADE+JEDI data. We build mean energy flux distributions in six auroral sub-regions (polar, main, and outer emissions in both hemispheres), combining JADE and JEDI data from PJ3 to PJ35, mapped to the SIII frame with the JRM33 model including the current sheet. We fit them using MCMC with the classical single-kappa and 4-kappa distributions. The mean distributions show a monotonic power-law decay with an energy cutoff beyond ~500 keV in most sub-regions, although some individual spectra depart from it at intermediate energies. Mean energies range from ~21 to ~119 keV, and energy fluxes from ~9.5 to ~28.7 mW/m2. The classical single-kappa fit fails in all sub-regions, with κ converging to the lower bound of its prior range. We therefore introduce the 4-kappa distribution, a linear combination of four classical single-kappa distributions modulated by an exponential high-energy cutoff, which accurately fits all six sub-regions. At equal energy flux and mean energy, transport simulations show that the 4-kappa distribution deposits energy at lower altitude than the classical one and distributes it differently along the vertical, with implications for the UV color ratio, atmospheric chemistry and thermal structure, and ionospheric conductances. This distribution provides an analytical framework for realistic modeling of electron precipitation and UV auroral emissions at Jupiter.
Related
- The precipitation of protons and electrons in Jupiter's auroral regions: a statistical comparison based on Juno/JEDI data
- New and Updated Rossiter-McLaughlin Measurements for Three Hot Jupiter-Hosting M Dwarfs
- The SPT-Deep Cluster Catalog: Sunyaev-Zel'dovich Selected Clusters from Combined SPT-3G and SPTpol Measurements over 100 Square Degrees
- Propagation of a quasi-stationary zonal wavenumber-2 Rossby wave in Jupiter's stratosphere
- Energetic heavy ions in Jupiter's nightside inner and middle magnetosphere: Juno/JEDI statistics
BibTeX
@misc{benmahi2026energy,
title = {{Energy distributions of precipitating electrons in Jupiter's auroral regions from combined Juno/JADE and Juno/JEDI measurements}},
author = {B. Benmahi and V. Hue and N. André and B. Bonfond and M. Blanc and Z. -Y. Liu and B. H. Mauk and F. Allegrini and G. Clark and M. Devinat and G. Gronoff and T. Le Liboux and M. Barthélémy and C. Lefour and T. Cavalié and B. Benne and T. Gautier and T. Briand and J. A. Noble and J. A. Sinclair},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.34693},
eprint = {2609.34693},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.34693},
}
RIS
TY - UNPB
TI - Energy distributions of precipitating electrons in Jupiter's auroral regions from combined Juno/JADE and Juno/JEDI measurements
AU - B. Benmahi
AU - V. Hue
AU - N. André
AU - B. Bonfond
AU - M. Blanc
AU - Z. -Y. Liu
AU - B. H. Mauk
AU - F. Allegrini
AU - G. Clark
AU - M. Devinat
AU - G. Gronoff
AU - T. Le Liboux
AU - M. Barthélémy
AU - C. Lefour
AU - T. Cavalié
AU - B. Benne
AU - T. Gautier
AU - T. Briand
AU - J. A. Noble
AU - J. A. Sinclair
PY - 2026
DA - 2026/09/28
PB - arXiv
DO - 10.48550/arxiv.2609.34693
UR - https://arxiv.org/abs/2609.34693
AB - Jupiter's auroras are produced by magnetospheric electrons precipitating into its atmosphere. Juno/JADE and Juno/JEDI together measure these electrons from 100 eV to 1 MeV. However, their auroral spectra are poorly reproduced by the widely used kappa distribution, hereafter the classical single-kappa distribution. We aim to statistically characterize the energy flux distributions of precipitating auroral electrons and to derive a new phenomenological 4-kappa distribution better suited to JADE+JEDI data. We build mean energy flux distributions in six auroral sub-regions (polar, main, and outer emissions in both hemispheres), combining JADE and JEDI data from PJ3 to PJ35, mapped to the SIII frame with the JRM33 model including the current sheet. We fit them using MCMC with the classical single-kappa and 4-kappa distributions. The mean distributions show a monotonic power-law decay with an energy cutoff beyond ~500 keV in most sub-regions, although some individual spectra depart from it at intermediate energies. Mean energies range from ~21 to ~119 keV, and energy fluxes from ~9.5 to ~28.7 mW/m^2. The classical single-kappa fit fails in all sub-regions, with κ converging to the lower bound of its prior range. We therefore introduce the 4-kappa distribution, a linear combination of four classical single-kappa distributions modulated by an exponential high-energy cutoff, which accurately fits all six sub-regions. At equal energy flux and mean energy, transport simulations show that the 4-kappa distribution deposits energy at lower altitude than the classical one and distributes it differently along the vertical, with implications for the UV color ratio, atmospheric chemistry and thermal structure, and ionospheric conductances. This distribution provides an analytical framework for realistic modeling of electron precipitation and UV auroral emissions at Jupiter.
ER -