title: Galileo magnetometer measurements: a stronger case for a subsurface ocean at Europa.
abstract: On 3 January 2000, the Galileo spacecraft passed close to Europa when it was located far south of Jupiter's magnetic equator in a region where the radial component of the magnetospheric magnetic field points inward toward Jupiter. This pass with a previously unexamined orientation of the external forcing field distinguished between an induced and a permanent magnetic dipole moment model of Europa's internal field. The Galileo magnetometer measured changes in the magnetic field predicted if a current-carrying outer shell, such as a planet-scale liquid ocean, is present beneath the icy surface. The evidence that Europa's field varies temporally strengthens the argument that a liquid ocean exists beneath the present-day surface.
authors.affiliation: Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA 90095-1567, USA. mkivelson@igpp.ucla.edu
authors.forename: M G
authors.initials: MG
authors.lastname: Kivelson
authors.forename: K K
authors.initials: KK
authors.lastname: Khurana
authors.forename: C T
authors.initials: CT
authors.lastname: Russell
authors.forename: M
authors.initials: M
authors.lastname: Volwerk
authors.forename: R J
authors.initials: RJ
authors.lastname: Walker
authors.forename: C
authors.initials: C
authors.lastname: Zimmer
mesh_terms: D005118:Extraterrestrial Environment; D007053:Ice; D018538:Jupiter; D008280:Magnetics; D014867:Water
chemical_list: D007053:Ice; D014867:Water