The Plasma Environment of Titan as Seen by the Cassini Magnetometer

BERTUCCI, C.; NEUBAUER, F. M.; DOUGHERTY, M. K.; LAW, A.; BACKES, H.; ACHILLEOS, N.; RUSSELL, C. T.; CASSINI MAG TEAM

Congreso; American Astronomical Society, DPS meeting #37; 2005

The measurements obtained by the Cassini magnetometer (MAG) during the first close flybys of Titan provided invaluable information on its internal properties as well as on the interaction with its plasma environment. On the one hand, MAG observations suggest the virtual absence of a significant dynamo-generated magnetic field. This sets important constraints on the dynamics and compositional properties of Titan´s interior. Consistently, MAG observations also provide evidence for a direct interaction between Titan´s extensive atmosphere/exosphere and the surrounding magnetized plasma flowing past Titan. During the first 5 close flybys Titan was inside Saturn´s magnetosphere. As a result, the charged particles from the satellite´s atmosphere and exosphere were interacting with the Kronian co-rotating magnetospheric plasma. This complex electromagnetic collisionless coupling produces two major alterations in Saturn´s co-rotating, frozen-in magnetic field: first, the ´pileup´ of this magnetic field in front of Titan´s ionosphere, and second, the ´draping´ of the magnetic field lines around the satellite which forms a dual lobe magnetic tail in the flow downstream of Titan. In this presentation, we summarize the observations obtained by MAG across the magnetic tail of Titan and we discuss the variability of Titan´s "induced magnetosphere" as a function of the upstream conditions as the satellite samples different local times on its orbit around Saturn.