Monte Carlo Simulation of Transport

ISSN： 0021-9991

Source： Journal of Computational Physics, Vol.129, Iss.1, 1996-11, pp. : 170-180

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Abstract

This paper is concerned with the problem of transport in controlled nuclear fusion as it applies to confinement in a tokamak or stellarator. Numerical experiments validate a mathematical model of Paul R. Garabedian in which the electric potential is determined by quasineutrality because of singular perturbation of the Poisson equation. The Monte Carlo method is used to solve a test particle drift kinetic equation. The collision operator drives the distribution function in velocity space towards the normal distribution, or Maxwellian, as suggested by the central limit theorem. The detailed structure of the collision operator and the role of conservation of momentum are investigated. Exponential decay of expected values allows the computation of the confinement times of both ions and electrons. Three-dimensional perturbations in the electromagnetic field model the anomalous transport of electrons and simulate the turbulent behavior that is presumably triggered by the displacement current. Comparison with experimental data and derivation of scaling laws are presented.