Properties of Saturn's Magnetopause: Time-Dependent Morphology and Dynamics

ACHILLEOS, N.; ARRIDGE, C.; BERTUCCI, C. S.; BURTON, M.; DOUGHERTY, M. K.; KHURANA, K. K.; RUSSELL, C. T.; SMITH, E. J.; TSURUTANI, B. T.

Congreso; AGU Fall Meeting 2005; 2005

Magnetopause crossings observed by the Cassini spacecraft's magnetometer (MAG) instrument have been used to derive a new model for the Kronian magnetopause [Arridge et al. 2005, submitted] which includes both pressure-dependent size and shape terms. Our model shows that as the solar wind pressure increases, the flaring of the model decreases, consistent with the distribution of particle stresses inside the magnetosphere. This model is first summarised, compared to models based on Pioneer and Voyager observations [Slavin et al. 1985; Maurice et al. 1996], and then applied to regularly sampled orbits of the spacecraft in order to build up a statistical distribution of the subsolar (standoff) distance of the magnetopause surface. The orbital data used indicate that the most probable standoff distance is in the range 24-28 Saturn radii, corresponding to solar wind dynamic pressures 0.01 to 0.02 nPa. Unlike the case of Jupiter, the distribution of standoff distances is consistent with a normal distribution and shows no evidence for bimodality.