Demonstrating ThunderBoltz: An Open-Source 0D DSMC Boltzmann Solver for Plasma Transport and Chemical Kinetics

Large-scale 3D plasma codes involve a complex assembly of procedures that are not always necessary to test effects of underlying physical models. Here we present ThunderBoltz, a lightweight, publicly available 0D Direct Simulation Monte Carlo (DSMC) code designed to accommodate a generalized combination of species and arbitrary cross sections without the overhead of expensive field solves. It can efficiently produce high-quality electron velocity distributions in applied AC/DC E-field and static B-field scenarios. The code is built in the C++ standard library and includes a convenient Python interface which allows for input file generation from the LXCat data base, electron transport and reaction rate post processing, input parameter constraint satisfaction, calculation scheduling, and diagnostic plotting.

In this work we compare ThunderBoltz transport calculations against Bolsig+ calculations, benchmark test problems, and swarm experiment data, finding good agreement with all three in the appropriate field regimes. In addition to this, we present example use cases where the electron, ion, and background neutral particle species are self-consistently evolved providing an ability to model the background kinetics, a feature that is absent in fixed background Monte Carlo and n-term Boltzmann solvers.