HR: 1340h
AN: P43A-1007    [Abstracts]
TI: A Multi-Fluid Study of the Centrifugal Interchange Cycle in Saturn's Inner Magnetosphere
AU: * Kidder, A R
EM: ariah@ess.washington.edu
AU: Winglee, R M
EM: winglee@ess.washington.edu
AB: Centrifugal interchange is a process widely observed by the Cassini spacecraft in Saturn's inner magnetosphere. A 3D multi-fluid global model of the Kronian magnetosphere shows that Saturn's gravity, magnetic field, and convection electric field modulate the growth of this interchange process. The model is used to quantify both components: the inward injections and the outward-moving outwelling of the interchange cycle. The model shows finger-like injections of hot tenuous plasma alternating between cooler spiral arm regions of denser plasma. These features are ubiquitous in the equatorial plane between 5-12 R_S and persist for several hours, though their generation is dependent on the prevailing conditions in both the inner magnetosphere and the solar wind forcing. Using a distributed Enceladus source of water group ions, and altering its concentration relative to the ionospheric ions, we see that a relative concentration of heavier ions affects the extent and definition of the finger- like cool, dense outwelling plasma. Additionally, the direction of the interplanetary magnetic field (IMF) can modulate the size of the fingers. Results address the radial velocity, ion and electron densities, magnetic and electric fields in these injection regions, as well as the time and spatial scales on which they persist. Model spectrograms are compared to the bulk parameters observed by Cassini.
DE: 2730 Magnetosphere: inner
DE: 2740 Magnetospheric configuration and dynamics
DE: 2753 Numerical modeling
DE: 2760 Plasma convection (2463)
DE: 6275 Saturn
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting