Interaction of the Saturnian Magnetospheric Plasma with Titan: How good are the Lessons from Venus?

WEI, H.; RUSSELL, C. T.; BERTUCCI, C.; NEUBAUER, F. M.; DOUGHERTY, M. K.

Congreso; AGU Fall Meeting 2006; 2006

Our early understanding of the interaction of the corotating magnetospheric plasma with Titan was strongly influenced by our understanding of the supersonically flowing solar wind with Venus but also comets and even Io. One aspect of the Venus interaction that was correctly not expected to arise at Titan was a bow shock. Nevertheless we do expect a compressional wave to arise as pressure builds up to deflect the flow. Cassini measurements show that this feature appears in the interaction as a large scale bending of the magnetic field far to each side of Titan, to distances greater than 10 R_T. At Venus there are relic fields induced in the ionosphere from earlier impressed magnetic fields with distinct orientations. The magnetic field encountering Titan, however, is generally roughly constant in direction except when Titan enters the magnetosheath. Thus testing this analogy is difficult. This is apart from the possibility that due to dynamic processes in the magnetosphere bow shock-like features may "flash-up" occasionally at Titan! Finally, the magnetotail of Venus is formed from a well-ordered slow mode expansion wave. Titan too has an Alfven-slow-mode wing but the appearance of this wing seems to be quite different from that of the swept-back Venus tail. This can be understood by the generally much smaller Alfven Mach number at Titan.