Validation of a 2D Impurity Transport Fluid Code Against KSTAR Tungsten Divertor Experiments

The tungsten accumulation in the core region of tokamak plasmas poses a significant challenge, as it leads to radiative cooling and dilution of main plasma species. [1] Notably, poloidal inhomogeneity of impurity is known to increase neoclassical impurity influx [2,3], thus motivating the development of a time-evolving 2D impurity transport fluid code with two different time scale. In a short time scale, the poloidal inhomogeneous impurity equilibrium is calculated by solving the parallel momentum equation [4]. For a longer time scale, its response for transport time scale and uses a numerically fitted transport coefficient model with the impact of the toroidal rotation [5,6] to achieve the saturation of the radial distribution of impurity density and parallel flow velocity. To validate the 2-D impurity transport code, we compared simulated impurity profiles with experimental results from the KSTAR 2023 campaign, which utilized a new tungsten divertor.