HR: 0800h
AN: P51A-1402    [Abstracts]
TI: Initial results from the Cassini CAPS Instruments at the Magnetopause of Saturn
AU: * McAndrews, H J
EM: hjm@mssl.ucl.ac.uk
AF: Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey, RH5 6NT United Kingdom
AU: Owen, C J
EM: cjo@mssl.ucl.ac.uk
AF: Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey, RH5 6NT United Kingdom
AU: Coates, A J
EM: ajc@mssl.ucl.ac.uk
AF: Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey, RH5 6NT United Kingdom
AU: Rymer, A M
EM: amr@mssl.ucl.ac.uk
AF: Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey, RH5 6NT United Kingdom
AU: Thomsen, M
EM: mthomsen@lanl.gov
AF: Los Alamos National Laboratory, Space and Atmospheric Science Group, NIS-1, Los Alamos, NM 87545 United States
AU: Gosling, J
EM: jgosling@lanl.gov
AF: Los Alamos National Laboratory, Space and Atmospheric Science Group, NIS-1, Los Alamos, NM 87545 United States
AU: Burch, J L
EM: jburch@swri.edu
AF: Southwest Research Institute, P.O Drawer 28510, San Antonio, TX 78228-0510 United States
AU: Dougherty, M K
EM: m.dougherty@imperial.ac.uk
AF: The Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2BW United Kingdom
AU: Young, D T
EM: dyoung@swri.edu
AF: Southwest Research Institute, P.O Drawer 28510, San Antonio, TX 78228-0510 United States
AB: Cassini entered orbit about Saturn on 1st July 2004 providing the first opportunity since Voyager to sample the Saturnian magnetospheric plasma regions. In this presentation we concentrate on the series of magnetopause encounters made by the spacecraft during its inbound trajectory, in particular we present data from the Cassini CAPS Electron Spectrometer (ELS) instrument which measures electrons from 0.58eV-26keV. The ELS instrument collected comprehensive electron data with an unprecedented temporal and energy response throughout the duration of these magnetopause crossings with the timing of the crossings being identified from the change of characteristics of the low energy electron populations. All crossings were made at local times of 07:43 to 07:48 MLT at magnetic latitudes of $\sim$ -15 degrees. The electron density and temperature within the magnetosheath regions were ~ 1.3$\times10^5$m$^{-3}$ and $\sim$ 40eV respectively. Within the magnetosphere the plasma was more rarefied (~ 1.2$\times10^4$m$^{-3}$) with an increased electron temperature of up to several 100eV. The crossings appeared to exhibit varied features associated with different magnetopause configurations. Some are associated with very sharp discontinuities in the electron data, possibly indicating a closed boundary, while others appear to be associated with an interior boundary layer. Some brief magnetosphere entries reveal unusual plasma regions separate from the magnetopause and immersed in the ambient plasma possibly indicating FTE's or boundary layers. We present results from an initial analysis of each of these crossings using the low energy electrons and incorporating results from the CAPS ion instruments where possible. Magnetic field data has also been used to put the particle results in context.
DE: 2700 MAGNETOSPHERIC PHYSICS
DE: 2724 Magnetopause, cusp, and boundary layers
DE: 2728 Magnetosheath
DE: 2731 Magnetosphere--outer
SC: Planetary Sciences [P]
MN: 2004 AGU Fall Meeting