The magnetic geometry of Titan's induced magnetosphere

BERTUCCI, C.; ACHILLEOS, N.; DOUGHERTY, M. K.

Congreso; American Geophysical Union, Fall Meeting 2011; 2011

As a result of the virtual absence of an intrinsic field at Titan, an induced magnetosphere is formed from the direct interaction between its atmosphere and the plasma environment. Observations at unmagnetized objects such as comets, or planets like Venus and Mars, have shown that the orientation of the magnetic field within an induced magnetosphere is, on average, symmetric with respect to the plane generated by the upstream magnetic field and plasma velocity vectors. Analyses of Voyager and early Cassini magnetometer data around Titan confirm this feature. In this work, we study the efficiency of the background magnetic field-based ´draping coordinate system´ (DRAP) introduced in Neubauer et al., [1] to organize Cassini magnetometer (MAG) measurements within the induced magnetosphere of Titan for all the close flybys of the Prime Mission where MAG data is available. We find that, in general, DRAP coordinates are efficient in organizing the orientation of the draped magnetic field according to the pattern expected for an induced magnetosphere, suggesting that the same system could be used to spatially organize plasma measurements. Departures from this picture are likely related to non stationarity in the upstream flow, fossil fields and, induced currents within Titan´s ionosphere and, probably, its interior. REFERENCES: Neubauer, F. M., et al. (2006). Titan´s near magnetotail from magnetic field and electron plasma observations and modeling: Cassini flybys TA, TB, and T3. [1] Journal of Geophysical Research, (2006) 111(A10), 1-15. doi: 10.1029/2006JA011676.