Implicit coupling of impurity transport at the SOL–core interface

The paper presents a numerical technique for modeling “trace” impurity transport in the scrape-off-layer (SOL) and core regions by implicit coupling of a three-dimensional (3D) edge Monte Carlo code like EMC3-Eirene Feng et al. (2004) [4], Reiter et al. (2005) [6] to a one-dimensional (1D) core model handled by a finite difference method. For given core plasma and transport coefficient profiles, certain types of particular solutions to the 1D model are pre-calculated under specific boundary conditions at the SOL–core interface. Linear combination of these solutions yields a general solution, which is then translated into “Monte Carlo language” by formulating a so-called “charge state transition probability” matrix. This matrix provides definitive boundary conditions at the SOL–core interface so that a self-consistent solution for both SOL and core is achievable without the need for SOL–core iteration.