Edge plasma simulations for a stellarator system with the two-dimensional transport code UEDGE

Abstract

A new and simple approach for stellarator edge modeling is presented. This is based on averaging of edge plasma parameters and introducing effective two-dimensional flux surfaces which allow us to use the UEDGE transport code, widely used for tokamak edge plasma modeling. This approach is applied to edge modeling of the Large Helical Device (LHD). It should be noted that our model is based on a two-dimensional configuration which is called the stellarator-equivalent tokamak (SET), while a stellarator system is inherently three-dimensional. Numerical simulations show that a bump of ion density in the private flux region just inside the separatrix appears, and flow reversal or a vortex structure of the ion flow is observed. Detailed analyses are necessary for validating this approach.