An approach to numerical simulation of the gas distribution in the atmosphere of Enceladus

摘要

In addition to being the major source of neutral gas and dust particles for the Saturnian E-ring and, ultimately, heavy ions for the Saturnian inner magnetosphere, Enceladus exhibits geological activity that has made it an object of recent intensive study. The interest has significantly increased after Cassini flybys in 2005 provided a detailed map of its surface, showing that most of its activity occurs in a region around the south pole of the satellite. Dust jets that were discovered during the flybys can be related to a set of localized gas sources that dominate the supply of material into the rarefied atmosphere of Enceladus. A comprehensive data analysis involves developing physical models that include all major processes occurring in the atmosphere. Such models can be used not only for calibration and understanding of data already available, but also could have a practical application for planning upcoming flybys. This work presents the results of the development and application of a kinetic model of the Enceladus' atmosphere consisting of a gas described in terms of its distribution function. The paper describes the basic principles of the model and gives a comparison with the observational data obtained with Cassini instruments.