HR: 0800h
AN: P51A-1397    [Abstracts]
TI: Saturn's Internal Magnetic Field
AU: * Giampieri, G
EM: g.giampieri@imperial.ac.uk
AF: Imperial College London, Department of Mathematics, London, SW7 2AZ United Kingdom
AU: Dougherty, M K
EM: m.dougherty@imperial.ac.uk
AF: Imperial College London, Space and Atmospheric Physics Group, London, SW7 2BZ United Kingdom
AU: Russell, C T
EM: ctrussell@igpp.ucla.edu
AF: UCLA, Institute of Geophysics and Planetary Physics, Los Angeles, CA 90024 United States
AU: Smith, E J
EM: edward.j.smith@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AB: We present new magnetic field data measured by the Cassini spacecraft during Saturn Orbit Insertion (SOI). The observed data are analyzed using standard inversion techniques, and a preliminary model of the internal field is presented. The zonal coefficients are found to be in good agreement with previous models derived from the Pioneer 11, Voyager 1 and Voyager 2 flybys. One striking feature of past models is the lack of non axisymmetric terms. We have reanalyzed past flyby data, and concluded that no certain conclusion on the axial symmetry of the field can be obtained from flyby observations alone, due to the uncertainty in our knowledge of the planetary rotation rate. We then propose a method for obtaining the first direct measurement of the rotation rate of the magnetic field, which is found to be 10h39m23.0s, in close agreement with the IAU value. A full picture of the internal magnetic field of Saturn, including its rotation state and the degree of its axial symmetry, will be revealed by Cassini, which will map the field at various longitudes and latitudes during the orbital tour.
DE: 5724 Interiors (8147)
DE: 5734 Magnetic fields and magnetism
DE: 6275 Saturn
DE: 2778 Ring current
SC: Planetary Sciences [P]
MN: 2004 AGU Fall Meeting