HR: 0800h
AN: P31A-0192    [Abstracts]
TI: Saturn's Drifting Period: Evidence From Analysis of Magnetic Perturbations.
AU: * Southwood, D J
EM: david.southwood@esa.int
AF: European Space Agency, HQ, 8-10 Rue Mario-Nikis, Paris, 75015, France
AU: * Southwood, D J
EM: david.southwood@esa.int
AF: Physics Department, Imperial College, London, SW7 2BZ, United Kingdom
AU: Kivelson, M G
EM: mkivelson@igpp.ucla.edu
AF: Inst. of Geophysics, UCLA, 6843 Slichter Hall, Los Angeles, CA 90095-1567, United States
AU: Dougherty, M
EM: m.dougherty@ic.ac.uk
AF: Physics Department, Imperial College, London, SW7 2BZ, United Kingdom
AB: It is well known that the SKR period has changed over time, increasing by ~0.5 percent per year during the Cassini epoch. This impacts many aspects of magnetospheric science but also poses a problem both for the elucidation of the internal field of Saturn and the rotation rate of the interior. Long term monitoring of the continuous radio signals has allowed derivation of a formula governing the evolution of the phase and thereby the change of period during the Cassini epoch up to August 2006 (Kurth et al., 2007). The radio data have the virtue of being nearly continuous but are not well suited for determining an instantaneous frequency and phase. We show evidence from the magnetometer data measured in situ by the Cassini spacecraft while the spacecraft is within the cam region (L shells less than 11 - 17) of fairly stable phase in the oscillations and thereby refine the estimates of the time varying period. We propose a mechanism whereby the magnetometer signal and the radio signal are synchronized based on the proposed phase model.
DE: 5704 Atmospheres (0343, 1060)
DE: 5706 Aurorae
DE: 5714 Gravitational fields (1221)
DE: 5734 Magnetic fields and magnetism
DE: 6275 Saturn
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting