AN INEXACT NEWTON ALGORITHM FOR SOLVING THE TOKAMAK EDGE PLASMA FLUIDEQUATIONS ON A MULTIPLY-CONNECTED DOMAIN

Newton's method is combined with a preconditioned conjugate gradient-l ike algorithm and finite volume discretization to solve the steady-sta te two-dimensional tokamak edge plasma fluid equations. A numerical ev aluation of the Jacobian is employed. Mesh sequencing, pseudo-transien t continuation, and adaptive damping are used to increase the radius o f convergence. The computations are performed on a multiply-connected curvilinear geometry in a fully coupled manner. The preconditioned con jugate gradient-like algorithm is shown to have a significant storage advantage over the previously used banded Gaussian elimination, while maintaining the excellent convergence characteristics of the overall a lgorithm. Simulations of a high recycling divertor and a gaseous diver tor on the DIII-D tokamak geometry are used to demonstrate algorithm p erformance. (C) 1995 Academic Press. Inc.