A Multi-Term Boltzmann Equation Toolset for Low Temperature Plasmas

Abstract

Low temperature plasma (LTP) models, such as fluid and global models, frequently rely on Boltzmann equation (BE) solvers for the fast calculation of rate and transport coefficients from cross section data. While multi-term BE solvers currently see strong support in the kinetic modeling community, two-term BE solvers remain the preferred choice in the greater pulsed power and plasma science community. The limitations of the two-term approximation are well known, yet it is still regularly assumed that the two-term approximation is suitable for applications in LTP models. Recent studies have demonstrated otherwise where, even in a simple 1D fluid model, the use of multi-term derived rate and transport coefficients yielded superior fluid model results compared to the same model using two-term derived rate and transport coefficients.Much of the reluctance in adopting multi-term BE solvers may be attributed to a lack of publicly available tools. Here, we report on the public release of MultiBolt v3.0.0 as a free and open-source C++ header library as well as its pre-compiled terminal-based executable and graphical user interface. We also report on the inclusion of new functionality in temperature dependence, superelastic collisions, and the object-oriented treatment of both discrete and analytic cross sections.