DSMC implementation of MD/QCT generated energy distributions for SO₂ + O collisions

The unique atmospheric conditions on the Jovian moon Io, ranging from cold surface temperatures to hyperthermal interactions with the Jovian plasma torus, make it of significant scientific interest. Direct Simulation Monte Carlo (DSMC) is typically used to model the rarefied Ionian atmosphere. Collisions between SO₂ and O are a dominant mechanism in the composition of the atmosphere. However, the accuracy of existing DSMC models in determining molecular internal energy distributions is unknown. As such, Molecular Dynamics/Quasi-Classical Trajectory (MD/QCT) studies are conducted to generate energy distributions for collisions between SO₂ and O. These distributions are presented and compared to common existing DSMC models and it is found that the MD/QCT-based distributions may present an improvement. Then, an approach for sampling from the new MD/QCT-based distributions in DSMC is developed. DSMC simulations are conducted for a 0-D heat bath with thermal non-equilibrium and a 2-D counter flow with conditions similar to Io to examine the effect of the new MD/QCT energy distributions.