TRANSPORT ANALYSIS OF DIVERTOR PLASMA IN JT-60U

A simple divertor model has been developed in order to analyze the divertor transport based on experimental data. The fluid equations are solved numerically in one dimension along the magnetic field lines. In contrast to the conventional divertor code, the boundary conditions are given by experimentally determined plasma parameters at the divertor plate, which are measured by Langmuir probes. The neutral particle transport is simulated in two dimensions by a Monte Carlo code. The interaction between the plasma and the neutral particles is solved self-consistently using an iterative procedure; the plasma parameters converge in a few iterations. The little computational time needed facilitates a systematic analysis of the divertor transport. By applying this model to the JT-60U divertor plasmas, the particle confinement time in the main plasma and the heat diffusivity in the scrape-off layer are evaluated.