The auroral footprint of Ganymede

[en] The interaction of Ganymede with Jupiter's fast rotating magnetospheric plasma gives rise to a current system producing an auroral footprint in Jupiter's ionosphere, usually referred to as the Ganymede footprint. Based on an analysis of ultraviolet images obtained with the Hubble Space Telescope we demonstrate that the auroral footprint surface matches a circular region in Ganymede's orbital plane having a diameter of 8 to 20 RG. Temporal analysis of the auroral power of Ganymede's footprint reveals variations of different timescales: 1) a 5 hours timescale associated with the periodic flapping of Jupiter's plasma sheet over Ganymede, 2) a 10 to 40 minutes timescale possibly associated with energetic magnetospheric events, such as plasma injections, and 3) a 100 s timescale corresponding to quasi-periodic fluctuations which might relate to bursty reconnections on Ganymede's magnetopause and/or to the recurrent presence of acceleration structures above Jupiter's atmosphere. These three temporal components produce an auroral power emitted at Ganymede's footprint of the order of ~0.2 GW to ~1.5 GW.

Disciplines :

Space science, astronomy & astrophysics

Author, co-author :

Grodent, Denis ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Labo de physique atmosphérique et planétaire (LPAP)

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

Radioti, Aikaterini ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Labo de physique atmosphérique et planétaire (LPAP)

Gérard, Jean-Claude ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Labo de physique atmosphérique et planétaire (LPAP)

Jia, Xianzhe; University of California, Los Angeles - UCLA > IGPP

Nichols, Jonathan D.; University of Leicester > DPA

Clarke, John T.; Boston University > CSP

Language :

English

Title :

The auroral footprint of Ganymede

Alternative titles :

[fr] L'empreinte aurorale de Ganymede

Publication date :

10 July 2009

Journal title :

Journal of Geophysical Research. Space Physics

ISSN :

2169-9380

eISSN :

2169-9402

Publisher :

American Geophysical Union (AGU), Washington, United States - District of Columbia

Volume :

114

Issue :

A07212

Peer reviewed :

Peer Reviewed verified by ORBi

Additional URL :

http://dx.doi.org/10.1029/2009JA014289

Funders :

F.R.S.-FNRS - Fonds de la Recherche Scientifique

Commentary :

Accepted for publication in the Journal of Geophysical Research. Copyright (2009) American Geophysical Union. Further reproduction or electronic distribution is not permitted. Grodent, D., B. Bonfond, A. Radioti, J.-C. Gérard, X. Jia, J.D. Nichols, J.T. Clarke (2009), The auroral footprint of Ganymede, J. Geophys. Res., doi:10.1029/2009JA014289. To view the published open abstract, go to http://dx.doi.org and enter the DOI.

Available on ORBi :

since 08 May 2009

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