Titan's Interaction With its Plasma Environment

BERTUCCI, C.; NEUBAUER, F. M.; LAW, A.; DOUGHERTY, M. K.; WAHLUND, J.; SZEGO, K.; COATES, A.; YOUNG, D.; ARRIDGE, C. S.; RUSSELL, C. T.; ACHILLEOS, N.

Congreso; AGU Fall Meeting 2005; 2005

Titan is perhaps one of the most outstanding laboratories in the solar system to study the interaction of the atmosphere of a weakly magnetized body with a wind of plasma. This is mainly due to the variability of the upstream conditions (especially the variation in the angle between the co-rotational flow and the solar EUV radiation direction) as Titan orbits around Saturn inside the Kronian magnetosphere. In this presentation we study the main features characterizing Titan´s plasma environment as seen by the plasma instruments onboard the Cassini Spacecraft. These measurements confirm the presence of a well-defined magnetic tail formed by highly draped magnetic fields that pile up on the upstream side as they become strongly mass loaded with colder and heavier plasma from Titan and the absence of a significant intrinsic dynamo-type magnetic field. This ´induced´ magnetosphere has a well-defined external boundary characterized by strong enhancements of the magnetic field draping and pileup and followed by important changes in the dominant plasma population which are attributed to the increasing influence of Titan´s exosphere. This boundary is characterized by strong rotations in the magnetic field that yield very well defined normal vectors which are usually perpendicular to the draped field. This sudden change in the topology of the magnetic field strongly alters the dynamics of the plasma around Titan. In particular, we compare these features with the very first observations obtained upstream from Titan during the T8 flyby.