Suitability of Moment Methods to Model the Ion Dynamics in a Low-Temperature Plasma

We present a study of the suitability of several moment methods to capture the ion dynamics in a bounded non-equilibrium low-temperature plasma between two electrically-floating walls under different pressure regimes. We use a set of kinetic simulations in order to study the properties of one-dimensional five-moment (1D 5M) closures. We discuss on the advantages and disadvantages of some of the most common moment methods: Grad’s closure, the quadrature method of moments (QMOM), the extended QMOM (EQMOM) and maximum entropy. For this study, we analyse the capability of each closure to capture the dynamics of the closing flux and its ability to retrieve the distribution function. The results show that the accuracy of each model largely depends on the pressure regime. In general, all the considered methods behave rather fine at high pressure and exhibit different challenges in order to represent the low-pressure regime.