HR: 17:30h
AN: P54A-06    [Abstracts]
TI: Structure of Saturn's Magnetosphere as Revealed by Energetic Particles
AU: * Krupp, N
EM: krupp@mps.mpg.de
AF: Max-Planck-Institut f\"ur Sonnensystemforschung, Max-Planck-Str. 2, Katlenburg-Lindau, 37191 Germany
AU: Woch, J
EM: woch@mps,mpg.de
AF: Max-Planck-Institut f\"ur Sonnensystemforschung, Max-Planck-Str. 2, Katlenburg-Lindau, 37191 Germany
AU: Lagg, A
EM: lagg@mps.mpg.de
AF: Max-Planck-Institut f\"ur Sonnensystemforschung, Max-Planck-Str. 2, Katlenburg-Lindau, 37191 Germany
AU: Lim, J
EM: lim@mps.mpg.de
AF: Max-Planck-Institut f\"ur Sonnensystemforschung, Max-Planck-Str. 2, Katlenburg-Lindau, 37191 Germany
AU: Krimigis, S M
EM: tom.krimigis@jhuapl.edu
AF: The Johns Hopkins University Applied Physics Laboratory, Johns Hopkins Road, Laurel, MD 20723 United States
AU: Mitchell, D G
EM: don.mitchell@jhuapl.edu
AF: The Johns Hopkins University Applied Physics Laboratory, Johns Hopkins Road, Laurel, MD 20723 United States
AU: Roelof, E C
EM: ed.roelof@jhuapl.edu
AF: The Johns Hopkins University Applied Physics Laboratory, Johns Hopkins Road, Laurel, MD 20723 United States
AU: Mauk, B H
EM: barry.mauk@jhuapl.edu
AF: The Johns Hopkins University Applied Physics Laboratory, Johns Hopkins Road, Laurel, MD 20723 United States
AU: Paranicas, C
EM: chris.paranicas@jhuapl.edu
AF: The Johns Hopkins University Applied Physics Laboratory, Johns Hopkins Road, Laurel, MD 20723 United States
AU: Livi, S
EM: stefano.livi@jhuapl.edu
AF: The Johns Hopkins University Applied Physics Laboratory, Johns Hopkins Road, Laurel, MD 20723 United States
AU: Armstrong, T P
EM: armstrong@ftecs.com
AF: Fundamental Technologies, Ponderosa Suite 9, Lawrence, KS 66046 United States
AU: Dougherty, M K
EM: m.dougherty@ic.ac.uk
AF: Imperial College London, Prince Consort Road, London, SW7 2BZ United Kingdom
AU: Kurth, W S
EM: william-kurth@uiowa.edu
AF: Univeriy of Iowa, Old Highway, Iowa City, IA 55042 United States
AU: Louarn, P
EM: philippe.louarn@cesr.fr
AF: Centre d'Etude Spatiale des Rayonnements, 9, avenue du Colonel Roche, Touluse, 31028 France
AU: Dandouras, I
EM: iannis.dandouras@cesr.fr
AF: Centre d'Etude Spatiale des Rayonnements, 9, avenue du Colonel Roche, Touluse, 31028 France
AU: Hamilton, D C
EM: dch@umd.edu
AF: University of Maryland, College Park, Greenbelt, MD 20743 United States
AB: At the end of June/beginning of July 2004 Cassini entered the magnetosphere of Saturn, 24 years after the last encounter of a spacecraft with the planet in 1981. Cassini entered the magnetosphere at about 08:00 local time 15 degrees below the equatorial plane, crossed the ring plane at a distance of 158500 km from the planet and reached 80230 km during closest approach, much closer than the smallest distance of Voyager. We report on results from the Low Energy Magnetospheric Measurement System (LEMMS), one out of three detector systems of the Magnetospheric Imaging Instrument (MIMI). MIMI/LEMMS is designed to investigate the global configuration and topology of the Kronian magnetosphere and to study dynamical processes. Its double-ended sensor is able to detect energetic electrons (15 keV- 5 MeV) and ions with energies above 30 keV separately. Several different regions inside the magnetosphere could be identified through changes and differences in the energetic particle characteristics: A lobe region with low ion and electron intensities, a plasma sheet region with higher intensities and very abrupt changes when the spacecraft enters/leaves the plasma sheet, the ring current region close to the planet with the highest measured intensities, and the region above the rings with extremely low particle intensities near background. Besides the very high intensities in the main radiation belts close to the planet and the very low intensities above the rings around closest approach results of MIMI/LEMMS observed the Kronian magnetosphere in a highly dynamic state indicated by so-called injection events and quasi-periodic fluctuations of the intensities with a period of about an hour. These periodicities have also been observed in magnetic field and plasma wave data on board Cassini. Preliminary analysis correlate these fluctuations with the motion of the plasma sheet of Saturn which either has a wavy surface or corrugated sheet structure within this period.
DE: 5739 Meteorology (3346)
DE: 6275 Saturn
SC: Planetary Sciences [P]
MN: 2004 AGU Fall Meeting