Universität zu Köln

Salveter, A. ORCID: 0000-0003-1030-8431, Saur, J. ORCID: 0000-0003-1413-1231, Clark, G. ORCID: 0000-0002-5264-7194, Sulaiman, A. ORCID: 0000-0002-0971-5016, Mauk, B. H. ORCID: 0000-0001-9789-3797, Connerney, J. E. P. ORCID: 0000-0001-7478-6462 and Bonfond, B. ORCID: 0000-0002-2514-0187 (2025). Investigating Magnetic Field Fluctuations in Jovian Auroral Electron Beams. Journal of Geophysical Research: Space Physics, 130 (7). pp. 1-20. Wiley. ISSN 2169-9380

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Abstract

[Artikel-Nr.: e2025JA033816] 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 min. 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 when the spacecraft is within four Jovian radii radial distance closer than radial distances four Jovian radii due to the digitization limit of the magnetometer. However, in all cases where Juno crosses the main auroral field lines beyond 4 RJ, the digitization limit is significantly reduced and we detect small‐scale magnetic field fluctuations of 2–10 nT consistent with a turbulent spectrum. Associated energy fluxes projected to Jupiter can exceed 1,000 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 dominantly contribute to power Jupiter's auroral processes.

Item Type:	Article
Creators:	Creators Email ORCID ORCID Put Code Salveter, A. UNSPECIFIED https://orcid.org/0000-0003-1030-8431 UNSPECIFIED Saur, J. UNSPECIFIED https://orcid.org/0000-0003-1413-1231 UNSPECIFIED Clark, G. UNSPECIFIED https://orcid.org/0000-0002-5264-7194 UNSPECIFIED Sulaiman, A. UNSPECIFIED https://orcid.org/0000-0002-0971-5016 UNSPECIFIED Mauk, B. H. UNSPECIFIED https://orcid.org/0000-0001-9789-3797 UNSPECIFIED Connerney, J. E. P. UNSPECIFIED https://orcid.org/0000-0001-7478-6462 UNSPECIFIED Bonfond, B. UNSPECIFIED https://orcid.org/0000-0002-2514-0187 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-806266
Identification Number:	10.1029/2025JA033816
Journal or Publication Title:	Journal of Geophysical Research: Space Physics
Volume:	130
Number:	7
Page Range:	pp. 1-20
Number of Pages:	20
Date:	5 July 2025
Publisher:	Wiley
ISSN:	2169-9380
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Geosciences > Institute for Geophysics and Meteorology
Subjects:	Earth sciences
Uncontrolled Keywords:	Keywords Language Large magnetic field perturbations coincide with Juno Ultraviolet Spectrograph (UVS) intense auroral arcs English Magnetic field fluctuations on temporal scales <2 s are only resolvable above 4 R J English Magnetic field fluctuations at <2 s above 4 R J coincide with auroral main emission zone English
['eprint_fieldname_oa_funders' not defined]:	Publikationsfonds UzK
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/80626