Classical drifts in the tokamak SOL and divertor: Models and experiment

Classical drifts offer potential explanations for a variety of physical phenomena such as poloidal asymmetries, possible extra pinch or outward flow of plasma depending on the B-t direction, non-ambipolarity of radial plasma flow and current flow towards the target. Their incorporation into 2D numerical codes is promising to greatly improve their predictive capacity. The paper contains basic analysis of drift and fluid flows, modified boundary conditions, ad-hoc models and summary of experimental results which are widely regarded as having their origin in drift motions. Unresolved issues of plasma transport are highlighted.