Development of a Non-Local Neoclassical Transport Code for Helical Configurations

The progress in a 3-dimensional, non-local neoclassical transport simulation code “FORTEC-3D” is described. The main purpose of the code is to solve the drift-kinetic equation in general a 3-dimensional configuration using the δf Monte Carlo method, and to calculate neoclassical fluxes and the time evolution of the ambipolar radial electric field simultaneously. This article explains new numerical schemes adopted in FORTEC-3D in order to overcome numerical problems, which happen especially in the cases where the bifurcation of radial electric field occurs. Examples of test simulation for an LHD magnetic field configuration with a bifurcated electric field are also shown. With improved numerical schemes, FORTEC-3D can calculate neoclassical fluxes and trace the time evolution stably for several ion collision times, which is sufficiently long to observe GAM damping and formation of the ambipolar electric field