Titan at the edge: 2. A global simulation of Titan exiting and reentering Saturn's magnetosphere at 13:16 Saturn local time

We use a multifluid/multiscale model of Titan inside Saturn's magnetosphere to examine how Titan's induced magnetosphere and ion tail are affected when Titan crosses Saturn's magnetopause at 13:16 Saturn local time (SLT). During the simulation Titan crosses Saturn's magnetopause twice, exiting and reentering Saturn's magnetosphere. The magnetic field in Saturn's magnetosheath is predominately northward. Once inside Saturn's magnetosheath, Titan's connection to Saturn's magnetosphere is removed by slow ionospheric convection. Evidence for reconnection at Titan is not seen. Inside the magnetosheath the plasma flow is not perpendicular to the magnetic field, and magnetic field lines do not strongly drape around Titan. Titan's ionosphere is extended in the magnetosheath because Titan's ionospheric plasma is not stripped away by convecting magnetic field at high altitudes. After Titan crosses back into Saturn's magnetosphere, the magnetospheric plasma and field removes Titan's extended ionosphere, and Titan's induced magnetosphere returns to a “typical” configuration. The simulation is used to determine the time scale of Titan's connection to Saturn's magnetic field lines or magnetosheath magnetic field lines after a magnetopause crossing. In the magnetosheath, slow (∼3 km/s) ionospheric convection removes Titan's connection to Saturn's magnetosphere in ∼1.8 h. After Titan crosses back into Saturn's rapidly rotating magnetosphere, Titan's connection to magnetosheath magnetic field lines is removed through ionospheric convection in ∼50 min. The results of the simulation are also compared to data from Cassini's T32 flyby. Key Points Titan disconnects from Saturn's magnetosphere through ionospheric convection Time scale for Titan to disconnect from Kronian (sheath) field is 108 (50) min In the magnetosheath Titan's induced magnetosphere is irregular