Universität zu Köln

Saur, Joachim, Duling, Stefan ORCID: 0000-0001-7220-9610, Wennmacher, Alexandre, Willmes, Clarissa, Roth, Lorenz, Strobel, Darrell F., Allegrini, Frederic, Bagenal, Fran ORCID: 0000-0002-3963-1614, Bolton, Scott J., Bonfond, Bertrand ORCID: 0000-0002-2514-0187, Clark, George, Gladstone, Randy, Greathouse, Thomas K., Grodent, Denis C., Hansen, Candice J., Kurth, William S., Orton, Glenn S., Retherford, Kurt D., Rymer, Abigail M. and Sulaiman, Ali H. (2022). Alternating North-South Brightness Ratio of Ganymede's Auroral Ovals: Hubble Space Telescope Observations Around the Juno PJ34 Flyby. Geophys. Res. Lett., 49 (23). WASHINGTON: AMER GEOPHYSICAL UNION. ISSN 1944-8007

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Abstract

We report results of Hubble Space Telescope observations from Ganymede's orbitally trailing side which were taken around the flyby of the Juno spacecraft on 7 June 2021. We find that Ganymede's northern and southern auroral ovals alternate in brightness such that the oval facing Jupiter's magnetospheric plasma sheet is brighter than the other one. This suggests that the generator that powers Ganymede's aurora is the momentum of the Jovian plasma sheet north and south of Ganymede's magnetosphere. Magnetic coupling of Ganymede to the plasma sheet above and below the moon causes asymmetric magnetic stresses and electromagnetic energy fluxes ultimately powering the auroral acceleration process. No clear statistically significant timevariability of the auroral emission on short time scales of 100s could be resolved. We show that electron energy fluxes of several tens of mW m(-2) are required for its OI 1,356 angstrom emission making Ganymede a very poor auroral emitter.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Saur, Joachim UNSPECIFIED UNSPECIFIED UNSPECIFIED Duling, Stefan UNSPECIFIED orcid.org/0000-0001-7220-9610 UNSPECIFIED Wennmacher, Alexandre UNSPECIFIED UNSPECIFIED UNSPECIFIED Willmes, Clarissa UNSPECIFIED UNSPECIFIED UNSPECIFIED Roth, Lorenz UNSPECIFIED UNSPECIFIED UNSPECIFIED Strobel, Darrell F. UNSPECIFIED UNSPECIFIED UNSPECIFIED Allegrini, Frederic UNSPECIFIED UNSPECIFIED UNSPECIFIED Bagenal, Fran UNSPECIFIED orcid.org/0000-0002-3963-1614 UNSPECIFIED Bolton, Scott J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Bonfond, Bertrand UNSPECIFIED orcid.org/0000-0002-2514-0187 UNSPECIFIED Clark, George UNSPECIFIED UNSPECIFIED UNSPECIFIED Gladstone, Randy UNSPECIFIED UNSPECIFIED UNSPECIFIED Greathouse, Thomas K. UNSPECIFIED UNSPECIFIED UNSPECIFIED Grodent, Denis C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Hansen, Candice J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Kurth, William S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Orton, Glenn S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Retherford, Kurt D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Rymer, Abigail M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Sulaiman, Ali H. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-693062
DOI:	10.1029/2022GL098600
Journal or Publication Title:	Geophys. Res. Lett.
Volume:	49
Number:	23
Date:	2022
Publisher:	AMER GEOPHYSICAL UNION
Place of Publication:	WASHINGTON
ISSN:	1944-8007
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language IO Multiple languages Geosciences, Multidisciplinary Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/69306