Simulation of the Saturnian magnetospheric interaction with Titan

Flowing plasma interactions with small bodies in the solar system are frequ ently 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 ion s added to the flow in the vicinity of the body. Titan represents an Import ant example of this type of system and is scheduled to be probed in some de tail 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 intera ction region is dominated by the heavy ion gyroradii of the ambient and pic kup ions rather than the size of Titan and is found to depend on the mass l oading 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 affe ct what was observed.