Simulation of the Saturnian magnetospheric interaction with Titan

Abstract

Flowing plasma interactions with small bodies in the solar system are frequently complicated by the significant size of the ion gyroradii relative to the scale size of the body and the interaction region. This situation often applies to both the flowing ion populations and the atmospheric pickup ions added to the flow in the vicinity of the body. Titan represents an important example of this type of system and is scheduled to be probed in some detail during the Cassini mission tour of Saturn. Initial results from global hybrid (particle ions, fluid electrons) numerical simulations of Saturn's magnetospheric plasma encountering Titan's ionosphere reveal the complexity of the interaction introduced by the ion kinetics. The scale of the interaction region is dominated by the heavy ion gyroradii of the ambient and pickup ions rather than the size of Titan and is found to depend on the mass loading of the magnetospheric flow encountering Titan. Comparison with data from the Voyager 1 flyby suggests that ion kinetics as well as the relative orientations of external plasma ram and pickup ion production regions affect what was observed.