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AGU: Journal of Geophysical Research, Space Physics

 

Keywords

  • Ganymede
  • Jupiter
  • auroral footprint

Index Terms

  • Planetary Sciences: Solar System Objects: Ganymede
  • Planetary Sciences: Solar System Objects: Jupiter
  • Magnetospheric Physics: Auroral phenomena
  • Planetary Sciences: Fluid Planets: Magnetospheres
  • Magnetospheric Physics: Planetary magnetospheres
Abstract
Cited By (4)
 

Abstract

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 114, A07212, 10 PP., 2009
doi:10.1029/2009JA014289

Auroral footprint of Ganymede

Denis Grodent

Institut d'Astrophysique et de Géophysique, Laboratory for Planetary and Atmospheric Physics, Université de Liège, Liège, Belgium

Bertrand Bonfond

Institut d'Astrophysique et de Géophysique, Laboratory for Planetary and Atmospheric Physics, Université de Liège, Liège, Belgium

Aikaterini Radioti

Institut d'Astrophysique et de Géophysique, Laboratory for Planetary and Atmospheric Physics, Université de Liège, Liège, Belgium

Jean-Claude Gérard

Institut d'Astrophysique et de Géophysique, Laboratory for Planetary and Atmospheric Physics, Université de Liège, Liège, Belgium

Xianzhe Jia

Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California, USA

Jonathan D. Nichols

Department of Physics and Astronomy, University of Leicester, Leicester, UK

John T. Clarke

Center for Space Physics, Boston University, Boston, Massachusetts, USA

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 8–20 RG. Temporal analysis of the auroral power of Ganymede's footprint reveals variations of different timescales: (1) a 5-hour timescale associated with the periodic flapping of Jupiter's plasma sheet over Ganymede, (2) a 10–40 minute timescale possibly associated with energetic magnetospheric events, such as plasma injections, and (3) a 100-s timescale corresponding to quasiperiodic 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 to ∼1.5 GW.

Received 24 March 2009; accepted 8 May 2009; published 10 July 2009.

Citation: Grodent, D., B. Bonfond, A. Radioti, J.-C. Gérard, X. Jia, J. D. Nichols, and J. T. Clarke (2009), Auroral footprint of Ganymede, J. Geophys. Res., 114, A07212, doi:10.1029/2009JA014289.

Cited By

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