Intrinsic magnetic Field of Titan Upper limit to the dipole moment

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

Congreso; AGU Spring Meeting 2007; 2007

Titan is embedded in the Saturnian corotating magnetosphere with its orbit lying in the equatorial plane at radius of 20 Saturn radii. The interaction of Titan with this flowing magnetospheric plasma is complex due to the time variation of external conditions and the physics of the interaction with the neutral atmosphere and the ionosphere. A search for any intrinsic magnetic field of Titan must be carried out at low altitudes, where the complexities of the interaction are minimized. Large scale magnetic fields are observed below Titan's ionopause and these fields change both magnitude and orientation at low altitudes. The variability of these fields suggests that external fields and ionospheric currents contribute to the field seen at low altitudes, but if the interior of Titan is electrically conducting the radial component of the field should be least affected by them. Thus the radial component of the magnetometer data between 1100 km and 950 km (periapsis) are studied to determine how much of these fields may be due to an intrinsic dipole moment. By combining data at polar regions and equatorial regions, the dipole moments aligned in three Cartesian axes (g10, g11, h11) are inverted from the data. Pass to pass consistencies of the dipole moments allow us to estimate an upper limit of the intrinsic field. The probable error of the mean of the g10 term is sufficiently high that this value is consistent with zero, but the other two components may be statistically different than zero. The upper limit to the magnetic moment from these data is about 1.2 nT Rt 3.