HR: 0800h
AN: P41B-05    [Abstracts]
TI: Latitudinal Structure of Saturn's Ion Cyclotron Wave Belt from High-Inclination Orbits
AU: Leisner, J S
EM: jleisner@ess.ucla.edu
AF: Institute of Geophysics, University of California 405 Hilgard Ave, Los Angeles, CA 90095, United States
AU: * Russell, C T
EM: ctrussell@igpp.ucla.edu
AF: Institute of Geophysics, University of California 405 Hilgard Ave, Los Angeles, CA 90095, United States
AU: Dougherty, M K
EM: m.dougherty@imperial.ac.uk
AF: Space and Atmospheric Physics, Prince Consort Road South, London, SW 7 2BM, United Kingdom
AU: Persoon, A M
EM: ann-persoon@uiowa.edu
AF: Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242, United States
AU: Blanco-Cano, X
EM: xbc@geofisica.unam.mx
AF: Instituto de Geofisica, UNAM, Coyoacan Ciudad Universitaria, Mexico D F, 04510, Mexico
AU: Strangeway, R J
EM: strange@igpp.ucla.edu
AF: Institute of Geophysics, University of California 405 Hilgard Ave, Los Angeles, CA 90095, United States
AU: Cowee, M M
EM: mcowee@igpp.ucla.edu
AF: Institute of Geophysics, University of California 405 Hilgard Ave, Los Angeles, CA 90095, United States
AB: In late 2006, the inclination of the Cassini spacecraft's orbits rose from nearly zero to about fifty-five degrees. Consequentially, new understanding of the latitudinal structure of the ion cyclotron waves was obtained when the spacecraft passed through the equatorial plane. The wave amplitudes peaks not at the equator, but at a height of +/- 0.2 Rs, with a slight bias to the southern hemisphere and decreases rapidly after that, disappearing by about 0.3 Rs. Surprisingly, the wave frequencies are different from those we noted on the equatorial passes, with the frequency being higher as the spacecraft approaches the equator and lower as it leaves. This velocity shift is best explained by Doppler shifting due to spacecraft motion. With Cassini's velocity of 12 km/s and the observed frequencies, we calculate that these waves have phase velocities near 35 km/s, around one third of the Alfven speed. We also find that within 0.1 Rs of the equatorial plane, the waves are propagating in both directions, but outside of that region, the waves propagate primarily away from the equatorial plane.
DE: 2732 Magnetosphere interactions with satellites and rings
DE: 2772 Plasma waves and instabilities (2471)
DE: 5737 Magnetospheres (2756)
DE: 6275 Saturn
SC: Planetary Sciences [P]
MN: 2007 Joint Assembly