HR: 1340h
AN: P43A-1020    [Abstracts]
TI: Thermal Plasma Flow in Saturn's Inner Magnetosphere.
AU: * Wilson, R J
EM: rjw@lanl.gov
AF: Los Alamos National Laboratory, PO Box 1663, MS D466, Los Alamos, NM 87545, United States
AU: Tokar, R L
EM: rlt@lanl.gob
AF: Los Alamos National Laboratory, PO Box 1663, MS D466, Los Alamos, NM 87545, United States
AU: Henderson, M G
EM: mghenderson@lanl.gov
AF: Los Alamos National Laboratory, PO Box 1663, MS D466, Los Alamos, NM 87545, United States
AU: Thomsen, M F
EM: mthomsen@lanl.gov
AF: Los Alamos National Laboratory, PO Box 1663, MS D466, Los Alamos, NM 87545, United States
AU: Hill, T W
EM: hill@rice.edu
AF: Rice University, Physics and Astronomy Department MS 108, Houston, Tx 77251-1892, United States
AU: Pontius, D
EM: dpontius@bsc.edu
AF: Birmingham Southern College, 900 Arkadelphia Rd, Birmingham, AL 35254, United States
AB: Ion counting data from the Cassini plasma spectrometer (CAPS) in Saturn's inner magnetosphere are utilized to calculate bulk plasma moments including densities, temperatures, and flow velocities. The study covers radial distances from about 5.5 to 10.0 R_S, outside of the Encleadus orbit and the region where significant fresh pick up ions are observed¹. In order to generate the ion moments from the non-spinning craft and a restricted view of phase space, a forward modeling approach is utilized where two Maxwellian populations (a light ion (H⁺) and a water group ion (W⁺)) are fit to the available data. Data are processed from the equatorial plane during periods of actuator arm activity yielding good CAPS viewing, i.e. through the predominant plasma flow direction on each actuator sweep. The magnetospheric plasma is found to be sub co-rotating in this region at about 80%. This is in good agreement with velocity results from MIMI data despite their results not being confined to the equatorial plane, while the densities calculated also agree well with density values from RPWS. The W⁺ temperature anisotropy appears to be >1 at low values of R_S and becomes more isotropic at larger distances. Using the generated ion moments, estimates of the mass loading throughout this region are given. 1.) Tokar, R.L. et al., this meeting.
DE: 2756 Planetary magnetospheres (5443, 5737, 6033)
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting