Dependence of divertor asymmetries on the toroidal magnetic field

Abstract

A study of the effect of toroidal magnetic field (Bt) on the divertor asymmetries is carried out with a plasma transport code under BOUT++ framework with the magnetic equilibria from EAST and C-Mod. For the simulation cases with drifts, the density is larger at the inner divertor target, while the temperature and heat flux are larger at the outer divertor target. The ratio of the total particle flux at the outer target to that of the inner target increases with increasing Bt, while the ratio of the total heat flux at the outer target to that of the inner target decreases with increasing Bt. The in–out divertor asymmetries of both total particle and heat fluxes get weaker with increasing Bt. Further analysis shows that the edge radial transport induced by drifts is much weaker for the simulation case with higher Bt, indicating that drift-driven divertor asymmetries may be less important for future tokamaks with high Bt.