Titan's magnetic wake: Atmospheric or magnetospheric interaction

We compare the magnetic field topology in the Titan wake to an idealized pi cture of magnetic field lines draping about a conductive nonmagnetic obstac le. It is shown that in the inner part of the wake the magnetic field pictu re differs significantly from that expected for an idealized draping: The t ransverse magnetic field component rotates by 90 degrees as compared with t he direction of the upstream transverse magnetic field. Another difference is the existence of a deep magnetic field minima separating the inner and o uter parts of the wake. Transverse magnetic field rotation can be explained neither by temporal changes in the upstream magnetic field nor by reconnec tion processes in the wake. We find that this behavior of the transverse ma gnetic field can be explained at least qualitatively if one assumes the exi stence of a small intrinsic magnetic field of Titan. An effective magnetic dipole of 10(21) G cm(3) can account for the observed topology of the Titan magnetic wake. The origin of this field may be related to a residual magne tization of Titan's crust or to induction in a conducting ionosphere of the satellite. We present results of MI-ID simulations which support the above theoretical conclusion.