Asymptotic Preserving and Multiscale Methods for Kinetic and Hyperbolic Problems

Monte Carlo methods with negative particles

Bokai Yan

University of California, Los Angeles


Long range Coulomb collisions between charged particles (electrons and ions) dominate the nonequilibrium dynamics in plasma. However, numerical simulations of these non-equilibrium processes become challenging as the system approaches equilibrium, because the widely used particle methods mainly sample from the equilibrium part and hence are highly inefficient. In this talk I present a novel Monte Carlo method with "negative" particles, which represent defect in the equilibrium part. This is a hybrid type method, which saves the major cost in simulating near-equilibrium dynamics. This method is designed for the general bilinear collision operators and then applied to the Coulomb collisions. Various numerical simulations demonstrate the high accuracy and efficiency.