Kinetic simulation of neutral and weakly ionized gases

Many phenomena in neutral and weakly ionized gases can be described accurately only by kinetic-level models. This paper reports on progresses in kinetic models where the elementary processes are included by stochastic methods. Different collision models are used: while some allow an accurate description of the related cross-sections, others offer a simpler implementation. A special attention is devoted to the often overlooked problem of the kinetics of excited states. A few test cases are discussed to illustrate specific physical and numerical problems.