A METHOD TO SUPPRESS THE FINITE-GRID INSTABILITY IN PLASMA SIMULATIONS

A technique for suppressing the finite-grid instability in plasma simulation by jiggling the computation mesh is revisited. Linear dispersion theory suggests a reduction in growth rate of 50% when the mesh is randomly jiggled. With an implicit method, a large time step, and a grid with variable spacing, a nearly complete absence of the instability is observed. Because of its simplicity and low cost, it is suggested the method can be used routinely with variable zoning or adaptive grids to suppress the finite-grid instability. (C) 1994 Academic Press, Inc.