Analytical study of statistical error in coupled finite‐volume/Monte Carlo simulations of the plasma edge

摘要

>Plasma and neutral transport in the plasma edge region of magnetic confinement fusion devices is often simulated by iteratively coupling a finite volume (FV) code for the plasma with a Monte Carlo (MC) code for the neutral particles. Because of the statistical MC noise, the iterative scheme defines a Markov process for the plasma states. We derived relations between the iterative scheme and the statistical distribution of the plasma states. In this paper, we study in detail, for random noise coupling and in a generalized scalar setting, the relation between the artificial time step used in the iterative scheme and the variance of the plasma states. We show numerically that our new insights, gained from the scalar setting, still hold when simulating a simplified 1D plasma edge model.