HR: 15:05h
AN: P53B-06    [Abstracts]
TI: Evidence for Alfven Wave Plasma Heating in the Middle Magnetosphere of Saturn
AU: * Burch, J L
EM: jburch@swri.edu
AF: Southwest Research Institute, P. O. Drawer 28510, San Antonio, TX 78228-0510 United States
AU: Goldstein, J
EM: jgoldstein@swri.edu
AF: Southwest Research Institute, P. O. Drawer 28510, San Antonio, TX 78228-0510 United States
AU: Young, D T
EM: dyoung@swri.edu
AF: Southwest Research Institute, P. O. Drawer 28510, San Antonio, TX 78228-0510 United States
AU: Coates, A J
EM: ajc@mssl.ucl.ac.uk
AF: Mullard Space Science Laboratory, Hombury St. Mary, Dorking, Sur RH5 6NT United Kingdom
AU: Kurth, W S
EM: william-kurth@uiowa.edu
AF: University of Iowa, 210 VAN, Iowa City, IA 52242 United States
AU: Gurnett, D A
EM: donald-gurnett@uiowa.edu
AF: University of Iowa, 210 VAN, Iowa City, IA 52242 United States
AU: Dougherty, M K
EM: m.dougherty@imperial.ac.uk
AF: Imperial College, Blackett Lab, London, SW7 2BZ United Kingdom
AU: Crary, F J
EM: fcrary@swri.edu
AF: Southwest Research Institute, P. O. Drawer 28510, San Antonio, TX 78228-0510 United States
AU: Hill, T W
EM: hill@rice.edu
AF: Rice University, P. O. Box 1892, Houston, TX 77005 United States
AU: Andre, N
EM: andre@cesr.fr
AF: CESR, BP4346 , Toulouse, 31028 France
AU: Sittler, E C
EM: edward.c.sittler@nasa.gov
AF: NASA GSFC, Code 692, Greenbelt, MD 20771 United States
AB: On July 1, 2004, during the outbound pass following the Saturn orbital insertion of Cassini, the plasma spectrometer (CAPS), magnetometer, and plasma wave instrument observed a region of enhanced wave activity at radial distances between 6 and 7 Rs showing magnetic oscillations near the oxygen cyclotron frequency and lower frequency MHD waves with periods of a few minutes. The three largest low-frequency oscillations were associated on a one-to-one basis with significantly energized electrons and ions with energies ranging from 100s of eV up to several keV. Coincident with these events were deep total density dropouts indicated by the plasma wave data, as well as energy-dispersed energetic ion signatures signifying injections at local times a few hours earlier than the approximately 02 hours LT of the observation point. Centrifugal interchange is likely to be responsible for the apparent mixing of low-density hot plasma with higher density colder plasma. However, there is also evidence for strong Alfven perturbations (dB/B above 0.1) generated possibly by unstable pick-up ion distributions and leading to heating of both ions and electrons via Alfven wave dissipation along the plasma gradient that is observed in this region.
DE: 5737 Magnetospheres (2756)
DE: 6275 Saturn
SC: Planetary Sciences [P]
MN: 2004 AGU Fall Meeting