Publication Date: 2011.
During the Cassini Titan flyby on 2 July 2006 (T15), Titan was surrounded by a magnetospheric plasma flow with density about 0.1 cm‑3 as measured by Cassini Plasma Spectrometer (CAPS). A very low fraction of water group ions (O+) was detected in the flow dominated by hydrogen ions. We show that Titan's plasma interaction can be highly sensitive to the small fraction of oxygen ions in the magnetospheric flow. The ion quantities of the magnetospheric flow during the flyby were obtained from numerical moments calculated from the CAPS measurements; the average ambient magnetic field was determined using the Cassini magnetometer data. We simulated the flyby using a global hybrid model; the water group abundance in the flow was varied in three simulation runs. Based on the simulation results, the oxygen content has an especially notable effect on the extent of Titan's induced magnetosphere. A multi-instrument analysis was performed comparing with the simulations, whereby a comprehensive picture of the plasma properties around Titan during this flyby was obtained. Comparisons between the hybrid model simulations and Cassini measurements during the flyby point toward O+ density in the undisturbed magnetospheric flow having been around 0.008 cm‑3, which would have accounted for one half of the dynamic pressure of the flow.
Author affiliation: Sillanpää, I.. Southwest Research Institute; Estados Unidos
Author affiliation: Young, D. T.. Southwest Research Institute; Estados Unidos
Author affiliation: Crary, F.. Southwest Research Institute; Estados Unidos
Author affiliation: Thomsen, M.. Los Alamos National Laboratory,; Estados Unidos
Author affiliation: Reisenfelc, D.. University of Montana; Estados Unidos
Author affiliation: Wahlund, J. E.. Swedish Institute of Space Physics; Suecia
Author affiliation: Bertucci, Cesar. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina
Author affiliation: Kallio, E.. Finnish Meteorological Institute,; Finlandia
Author affiliation: Jarvinen, R.. Finnish Meteorological Institute; Finlandia
Author affiliation: Janhunen, P.. Finnish Meteorological Institute,; Finlandia
Repository: CONICET Digital (CONICET). Consejo Nacional de Investigaciones Científicas y Técnicas