Asymptotic Preserving and Multiscale Methods for Kinetic and Hyperbolic Problems

Monte Carlo methods with negative particles

Bokai Yan

University of California, Los Angeles
[SLIDES]

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.