Investigating Magnetic Field Fluctuations in Jovian Auroral Electron  Beams

[en] The Juno spacecraft provides a unique opportunity to explore the mechanisms generating Jupiter's aurorae. Past analyses of Juno data immensely advanced our understanding of its auroral acceleration processes, however, few studies utilized multiple instruments on Juno in a joint systematic analysis. This study uses measurements from the Juno Ultraviolet Spectrograph (UVS), the Jupiter Energetic particle Detector Instrument (JEDI), and the Juno Magnetometer (MAG) from the first 20 perijoves. On magnetic field lines associated with the diffuse aurora, we consistently find small-scale magnetic field fluctuations with amplitudes of up to 100 nT on time scales of seconds to 1 minute. On magnetic field lines directly linked to the main emission, the electron distribution is field-aligned, mostly broad-band in energy, and accompanied by large-scale magnetic field perturbations of several 100 nT on time scales of tens of min (except one case). These large-scale perturbations are generally associated with quasistatic field-aligned electric currents. Small-scale magnetic fields are not resolved over the main emission zone closer than radial distances 4 Jovian radii due to the digitization limit of the magnetometer. However, in all cases where Juno crosses the main auroral field lines beyond 4RJ, the digitization limit is significantly reduced and we detect small-scale magnetic field fluctuations of 2 nT to 10 nT consistent with a turbulent spectrum. Associated energy fluxes projected to Jupiter can exceed 1000 mW/m2. The general broad-band nature of the electron distributions and the consistent presence of small-scale magnetic field fluctuations over the main emission support that wave-particle interaction can dominantely contribute to power Jupiter's auroral processes.

Research Center/Unit :

STAR - Space sciences, Technologies and Astrophysics Research - ULiège

Disciplines :

Space science, astronomy & astrophysics

Author, co-author :

Salveter, A. ; Institute of Geophysics and Meteorology University of Cologne Cologne Germany

Saur, J. ; Institute of Geophysics and Meteorology University of Cologne Cologne Germany

Clark, G. ; The Johns Hopkins University Applied Physics Laboratory Laurel MD USA

Sulaiman, A. ; School of Physics and Atronomy Minnesota Institute for Astrophysics University of Minnesota Minneapolis MN USA

Mauk, B. H. ; The Johns Hopkins University Applied Physics Laboratory Laurel MD USA

J. E. P. Connerney

Bonfond, Bertrand ; Université de Liège - ULiège > Département d'astrophysique, géophysique et océanographie (AGO) > Labo de physique atmosphérique et planétaire (LPAP)

Language :

English

Title :

Investigating Magnetic Field Fluctuations in Jovian Auroral Electron Beams

Publication date :

05 July 2025

Journal title :

Journal of Geophysical Research. Space Physics

ISSN :

2169-9380

eISSN :

2169-9402

Publisher :

American Geophysical Union (AGU)

Volume :

130

Issue :

Peer reviewed :

Peer Reviewed verified by ORBi

Additional URL :

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2025JA033816

Funders :

DFG - Deutsche Forschungsgemeinschaft
F.R.S.-FNRS - Fonds de la Recherche Scientifique

Available on ORBi :

since 07 July 2025

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