HR: 1340h
AN: P33B-0242    [Abstracts]
TI: A Model of the Ionospheric System of Saturn's Main Rings
AU: * Bouhram, M
EM: mehdi.bouhram@cetp.ipsl.fr
AF: CETP/CNRS, 4 Avenue de Neptune, Saint-Maur, 94100 France
AU: Johnson, R E
EM: rej@virginia.edu
AF: 2Materials Science and Engineering, University of Virginia, Thornton Hall, Charlottesville, VA 22904 United States
AU: Berthelier, J
EM: jean-jacques.berthelier@cetp.ipsl.fr
AF: CETP/CNRS, 4 Avenue de Neptune, Saint-Maur, 94100 France
AU: Tokar, R L
EM: rlt@lanl.gov
AF: Los Alamos National Laboratory, Space and Atmospheric Science Group, Los Alamos, NM 87545 United States
AU: Illiano, J
EM: jean-marie.illiano@cetp.ipsl.fr
AF: CETP/CNRS, 4 Avenue de Neptune, Saint-Maur, 94100 France
AU: Baragiola, R A
EM: raul@virginia.edu
AF: 2Materials Science and Engineering, University of Virginia, Thornton Hall, Charlottesville, VA 22904 United States
AU: Teolis, B
EM: bdt4z@virginia.edu
AF: 2Materials Science and Engineering, University of Virginia, Thornton Hall, Charlottesville, VA 22904 United States
AU: Crary, F J
EM: fcrary@swri.edu
AF: Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238 United States
AU: Young, D T
EM: dyoung@swri.edu
AF: Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238 United States
AB: Plasma measurements were performed by the CAssini Plasma Spectrometer (CAPS) in the vicinity of Saturn's rings during orbit insertion on July 1, 2004. An analysis of the data has revealed the presence of an ionosphere above the A and B rings with O₂⁺ and O⁺ as major ions, suggesting the existence of an atmosphere made up of molecular oxygen (Young et al., 2005, Tokar et al., 2005). Oxygen molecules, originating from radiation-induced decomposition of ice, do not stick to the surfaces of the ring particles at the relevant temperature. It has been suggested that the molecules form an atmospheric layer in the vicinity of the rings, which could give rise to the observed ions. Here, we present results of a study based on a hybrid model of the ring ionosphere that uses a test-particle approach for ions and neutrals and incorporates a fluid of electrons. The model makes use of Monte Carlo techniques and takes into account chemical processes such as photo-ionization and charge exchange, as well as plasma processes leading to ion acceleration. Published plasma data from CAPS were used as constraint and the model provides a very satisfactory fit with ion data.
DE: 5719 Interactions with particles and fields
DE: 5780 Tori and exospheres
DE: 6265 Planetary rings
DE: 7807 Charged particle motion and acceleration
DE: 7823 Ionization processes (2423)
SC: Planetary Sciences [P]
MN: Fall Meeting 2005