COMPARISON OF EDGE PLASMA PARAMETERS BETWEEN LIMITER AND DIVERTOR CONFIGURATION IN TOKAMAK-REACTOR

摘要

The comparison of the edge plasma parameters and impurity fluxes between limitcr and divertor configuration of ITER-like devices is presented. A 2D model of hydrogen plasma and impurity ions is described. The model is based on the electron-ion Braginskii fluid equations for hydrogen plasma and rate equations for impurities. Arbitrary level of impurity ions concentration is assumed. Recycling of hydrogen, sputtering and self sputtering of carbon atoms at the target are taken into account. Equations of the model are solved in the slab geometry using 2D-multifluid numerical code EPIT, Problems of the plate erosion and impurity ions retention in limiter and divertor configurations are analysed. Results of calculations for ITER-like tokamak parameters are presented, showing that for low plasma density at the separatrix retention of impurity ions can be poor in both configurations. Impurity fluxes in the limiter configuration are acceptable from the reactor design point of view only for considerably high plasma density at the separatrix (n_e > 8 x 10~(19) m~(-3)).