SOLPS-ITER modeling of SOL-divertor plasmas with different configurations in EAST

SOLPS-ITER is used for modeling divertor plasmas in the experimental shot on the EAST tokamak with a carbon divertor. The modeling uses real divertor geometry and an MHD equilibrium from the shot. The modelled divertor configurations include upper single null (USN), disconnected double null (DDN) and lower single null (LSN). D0, D+1, e− and carbon impurity species sputtered from the first wall are included in the multi-fluid simulations. Neutral particles are traced with EIRENE in which neutral–neutral collisions in triangular grids are considered. The default physics models in the code are employed. The cross-field transport coefficients D, and deduced from the profile measurements at the targets are used with the assumption of , some of the deduced D are modified in the SOL and private regions and D, , in the core are adjusted in order to match better the experimental measurement at the target plates. Employed D, and drop from the core to the SOL, they may drop to neoclassic level within the edge transport barriers (ETBs). A ballooning effect on the transport coefficients is introduced. The computational contour profiles of electron temperature in the divertor regions and the computational profiles of plasma pressure and electron temperature at the mid-plane (the upstream) and at the target plate show the sheath limited (low recycling) operation regime. The calculated profiles of electron density ne, electron temperature Te, particle flux f , parallel ion saturation current and parallel power flux P along the target plates of the divertor are compared to the experimental measurements. Using the deduced and adjusted cross-field transport coefficients, when the measurement errors are considered the calculated and measured profiles have a relatively good match, the computational profiles are similar to the measured profiles, the profiles peaked at the separatrix strike points. The most peak values f s of calculated profiles are in the range of the measured error-bars , only in several matched profiles f s is out of the range of the error-bar, but, relative error does not exceed . When full drifts are taken into account in the entire SOL and the private flux regions the calculated profiles have better match to the measured profiles and the modeling results show the drifts enhance the divertor asymmetry.