HR: 1340h
AN: P43A-0947    [Abstracts]
TI: A Scale Height Model of Saturn's Plasma Disk
AU: * Persoon, A M
EM: ann-persoon@uiowa.edu
AF: University of Iowa, Dept. of Physics and Astronomy, Iowa City, IA 52242 United States
AU: Gurnett, D A
EM: donald-gurnett@uiowa.edu
AF: University of Iowa, Dept. of Physics and Astronomy, Iowa City, IA 52242 United States
AU: Kurth, W S
EM: william-kurth@uiowa.edu
AF: University of Iowa, Dept. of Physics and Astronomy, Iowa City, IA 52242 United States
AU: Groene, J B
EM: joseph-groene@uiowa.edu
AF: University of Iowa, Dept. of Physics and Astronomy, Iowa City, IA 52242 United States
AB: In the year since Cassini was placed in orbit around Saturn on July 1, 2004, the spacecraft has passed through Saturn's inner magnetosphere thirteen times over latitudes ranging from +14 degrees to -21 degrees. Electron densities are derived from measurements of the upper hybrid resonance frequency by the Radio and Plasma Wave Science (RPWS) instrument for these thirteen passes. The objective of this study is to develop a model of the plasma density distribution that is valid within 20 degrees of the magnetic equator. We use a centrifugal scale height model to describe the plasma distribution in the region of the inner magnetosphere where the plasma exhibits a nearly source-free outward radial expansion, i.e., over the range 5 < L < 8 where L is the equatorial radius of the magnetic field line in Saturn radii. We show that the best fit to the electron density varies as n_e = n_O exp[-(1/3)(L²/H²)(1-cos⁶ λ)] where λ is the latitude and H is the scale height. The scale height is found to vary as L^1.94, from H = 0.7 at L = 5, to H = 1.7 at L = 8. The equatorial plasma density varies as n_O = 3.8 × 10⁴ (1/R)^3.94.
DE: 2730 Magnetosphere: inner
DE: 2756 Planetary magnetospheres (5443, 5737, 6033)
DE: 2772 Plasma waves and instabilities (2471)
DE: 5737 Magnetospheres (2756)
SC: Planetary Sciences [P]
MN: Fall Meeting 2005