Modeling, analysis, computation and application of kinetic equations

Accelerating the simulation of collisional plasma by using deviational particles

Bokai Yan

University of California, Los Angeles

Long range Coulomb collisions between charged particles (electrons and ions) play a crucial role in nonequilibrium plasma. Particle based methods such as Particle-In-Cell (PIC) methods and DSMC methods are widely used in simulating these processes. However, these methods become highly inefficient as the system approaches equilibrium, because the major cost is spent on simulating the meaningless collisions in equilibrium. In this talk I present a hybrid method for the spatial inhomogeneous plasma modeled by Vlasov-Poisson-Landau system. We evolve the equilibrium part by a grid based fluid solver and the deviation part by numerical particles. By using deviational particles, which could be both positive and negative, the particle number is reduced significantly in simulating near-equilibrium dynamics. However the use of deviational particles complicates the simulation of binary Coulomb collision. We have developed novel and efficiently algorithms to overcome this difficulty.