Two-dimensional numerical model for coupled core-edge-SOL transport simulations in tokamak plasma

摘要

A unified numerical model has been developed to investigate the plasma transport self-consistently in the core, edge pedestal and scrape-off layer (SOL) regions of tokamak fusion reactor. Tokamak plasma is described based on the modified Braginskii's two-fluid equations by taking into account a self-consistent model for heating and current drive. The recycling and gas-puffing neutrals are included using a simplified diffusion model. In order to treat the strong coupling among the three plasma regions efficiently, a fully two-dimensional (2-D) approach is employed by extending the well-developed 2-D SOL model deeply into the core region with the carefully-designed methods of operator splitting and fractional time step. This numerical approach enables us to implement a numerical code on the same numerical basis in the whole simulation domain. The preliminary results of numerical simulations show that the global transport and confinement depend significantly on temperature and density at the plasma edge, which are determined self-consistently in the course of computations. Modeling issues on the L-H transition axe discussed on the basis of this developed numerical model. Further comments are given on a poloidal asymmetry due to large toroidal and poloidal flow rotations in the core region of internal transport barrier discharges for the advanced tokamak operation.