American Geophysical Union Become an AGU Member
Subscribe to AGU Journals		 AGU Home AGU Publications

Read Full Article    Cited by

GEOPHYSICAL RESEARCH LETTERS, VOL. 24, NO. 17, PAGES 2163–2166, 1997

Energetic Particle Signatures at Ganymede: Implications for Ganymede’s Magnetic Field

D. J. Williams

The Johns Hopkins University Applied Physics Laboratory, Laurel, MD


B. H. Mauk

The Johns Hopkins University Applied Physics Laboratory, Laurel, MD


R. W. McEntire

The Johns Hopkins University Applied Physics Laboratory, Laurel, MD


E. C. Roelof

The Johns Hopkins University Applied Physics Laboratory, Laurel, MD


T. P. Armstrong

University of Kansas, Lawrence, KS


B. Wilken

MPAe, Katlenburg-Lindau, Germany


J. G. Roederer

University of Alaska, Fairbanks, AK


S. M. Krimigis

The Johns Hopkins University Applied Physics Laboratory, Laurel, MD


T. A. Fritz

Boston University, Boston, MA


L. J. Lanzerotti

Lucent Technologies, Murray Hill, NJ


N. Murphy

Jet Propulsion Laboratory, Pasadena, CA


Abstract

The second encounter of the Galileo satellite with the Galilean moon Ganymede provided energetic particle measurements showing effects due to the presence of that moon. Jovian corotation signatures, present on approach to and departure from the Ganymede system, suddenly become much smaller when Galileo enters what has been termed Ganymede’s magnetosphere. The location of these transitions agrees with magnetopause crossings identified by the magnetometer and plasma wave instruments. In Ganymede’s magnetosphere, energetic ion and electron distributions display loss cone signatures whenever the Energetic Particles Detector (EPD) views along the magnetic field line. The loss cone measurements are used to estimate Ganymede’s surface magnetic field along the satellite track. The results agree with model projections to Ganymede’s polar cap and support the existence of a Ganymede-intrinsic magnetic field. An evolution from single to double loss cone also occurs with increasing electron energy.

Received 14 March 1997; accepted 27 June 1997.

Read Full Article    Cited by

Citation: Williams, D. J., et al. (1997), Energetic Particle Signatures at Ganymede: Implications for Ganymede’s Magnetic Field, Geophys. Res. Lett., 24(17), 2163–2166.