PROGRESS IN 2-DIMENSIONAL PLASMA EDGE MODELING

A review is given of the status of various approaches dealing with tokamak edge related issues by employing two-dimensional numerical fluid codes for the main components of the edge plasma. The predictive capabilities of these models are assessed, in particular with regard to their completeness and the reliability of the transport coefficients. As the plasma edge characteristics in the favourable high recycling regime are determined by the mutual interaction of charged and neutral particle transport effects, sophisticated kinetic (often Monte Carlo) models for the neutral particles have been built into several of these 2D fluid programs. This allows for the first time consistently to study intrinsically 2D and multispecies effects, such as flow reversal or decoupling of plasma and impurity or helium ash flows.