Universität zu Köln

Salveter, A., Saur, J., Clark, G. and Mauk, B. H. (2022). Jovian Auroral Electron Precipitation Budget-A Statistical Analysis of Diffuse, Mono-Energetic, and Broadband Auroral Electron Distributions. J. Geophys. Res-Space Phys., 127 (8). WASHINGTON: AMER GEOPHYSICAL UNION. ISSN 2169-9402

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Abstract

Recent observations by the Juno spacecraft have shown that electrons contributing to Jupiter's main auroral emission appear to be frequently characterized by broadband electron distributions, but also less often mono-energetic electron distributions are observed as well. In this work, we quantitatively derive the occurrence rates of the various electron distributions contributing to Jupiter's aurora. We perform a statistical analysis of electrons measured by the JEDI-instrument within 30-1,200 keV from Juno's first 20 orbits. We determine the electron distributions, either pancake, field-aligned, mono-energetic, or broadband, through energy and pitch angles to associate various acceleration mechanisms. The statistical analysis shows that field-aligned accelerated electrons at magnetic latitudes greater than 76 degrees are observed in 87.6% +/- 7.2% of the intervals time averaged over the dipole L-shells according the main oval. Pancake distributions, indicating diffuse aurora, are prominent at smaller magnetic latitudes (<76 degrees) with an occurrence rate of 86.2% +/- 9.6%. Within the field-aligned electron distributions, we see broadband distributions 93.0% +/- 3.8% of the time and a small fraction of isolated mono-energetic distribution structures 7.0% +/- 3.8% of the time. Furthermore, these occurrence statistics coincide with the findings from our energy flux statistics regarding the electron distributions. Occurrence rates thus also characterize the overall energetics of the different distribution types. This study indicates that stochastic acceleration is dominating the auroral processes in contrast to Earth where the discrete aurora is dominating.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Salveter, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Saur, J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Clark, G. UNSPECIFIED UNSPECIFIED UNSPECIFIED Mauk, B. H. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-670158
DOI:	10.1029/2021JA030224
Journal or Publication Title:	J. Geophys. Res-Space Phys.
Volume:	127
Number:	8
Date:	2022
Publisher:	AMER GEOPHYSICAL UNION
Place of Publication:	WASHINGTON
ISSN:	2169-9402
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language JUPITERS POLAR-REGIONS; MAGNETOSPHERE; ACCELERATION; FOOTPRINTS; ENERGIES; BEAMS; WAVES Multiple languages Astronomy & Astrophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/67015