Titan's column density, which is about ten times that of Earth's atmosphere, makes it unique among the icy satellites in the outer solar system. One of the reasons Titan has been able to maintain such an atmosphere is its position within the Saturian Magnetosphere. Atmospheres similar in size to that of Titan would have been removed from the icy Galilean satellites by the plasma trapped in the Jovian magnetosphere (Johnson 2004). In this paper, we discuss the deposition of energy, the erosion and the expansion of the upper atmosphere of Titan using 3-D Direct Simulation Monte Carlo models (Shematovich et al. 2003; Michael et al. 2005). (These atmospheric processes are more adequately illustrated using 3-D models rather than 1-D models). Calculations are used to calibrate semi-empirical models of atmospheric sputtering (Johnson 1994) that are employed in interpreting Cassini data at Titan. We compare the energy deposited vs. altitude by energetic protons and oxygen ions to that deposited by the low energy plasma and the UV. Using a number of plasma conditions, the temperature and density vs. altitude above the exobase and the rate of escape are calculated and compared to available Cassini data on Titan's corona.
AAS/Division for Planetary Sciences Meeting Abstracts #39
- Pub Date:
- October 2007