Morphology of the magnetic field near Titan: Hybrid model study of the Cassini T9 flyby

KALLIO, E.; SILLANPÄÄ, I.; JARVINEN, R.; JANHUNEN, P.; DOUGHERTY, M.; BERTUCCI, C.; NEUBAUER, F.

GEOPHYSICAL RESEARCH LETTERS

AMER GEOPHYSICAL UNION

Año: 2007

0094-8276

We study the deformation and morphology of the magnetic field near Titan by a three-dimensional numerical quasi-neutral hybrid model (HYB-Titan). We analyze two runs, one in which the sub-rotating plasma consists of oxygen (O+) ions and protons (H+) and another with only protons. We find that both cases result in the generation of Alfvén wing-like flux tubes. In comparison with the proton-only case, the direction and magnitude of the magnetic field in the oxygen-rich flow case are in better agreement with Cassini magnetic field observations during its Titan T9 flyby on Dec. 26, 2006, suggesting that the sub-rotating plasma contained heavy ions. The oxygen-rich run also supports the hypotheses that (1) the sub-rotating flow direction was offset by ~30°-40° from the ideal rotating flow direction and that (2) the spacecraft was magnetically connected to the sunlit side of near-Titan space in the tail when it approached Titan on the T9 flyby.