Low-Rank Decomposition of Plasma Kinetic Distributions in the Collisional Transition Regime

The strength of collisional effects in a plasma can be summarized by the non-dimensional Knudsen number Kn. For very small values of Kn, plasma behavior is well-described by the 5N moment fluid model, including the Braginskii closure. When Kn is large, plasmas are best described by a fully kinetic model such as the Vlasov-Maxwell system. For intermediate values of the Knudsen number, i.e. 10 -2 < Kn <10, a reduced model that takes advantage of the smoothing nature of the collision operator while still capturing important non-equilibrium physics is desired.