Simulation study of the influence of the cross‐field anomalous diffusion on the tungsten impurity transport in the scrape‐off layer with activated drifts

Tungsten (W) impurity eroded from the divertor target can degrade the confinement performance of future fusion reactors. The mechanism of the effect of E × B drift on the W transport in the scrape‐off layer (SOL) was investigated with a fixed cross‐field anomalous particle diffusion coefficient for W ions ( D ⊥,W ) of 1 m 2 s −1 in our previous simulation work, which indicates that the W flux entering the confined region ( Γ enter ) and mean W concentration in the confined region () can be increased by more than one order of magnitude by drifts. In this work, the influence of the cross‐field anomalous diffusion on the W transport in the SOL is further investigated. The basic flow pattern of the W ion flux ( Γ W ) keeps when D ⊥,W varying from 0.5 to 3 m 2 s −1 , and Γ enter mainly comes from the hotter divertor region. Results show that D ⊥,W value affects the W leakage from divertor region and entry into confined region. Therefore, Γ enter and both decrease with increasing D ⊥,W . Mechanisms for cases w/wo drifts are compared.