EMC3-EIRENE modelling of tungsten behavior under resonant magnetic perturbations on EAST: Effects of tungsten sputtering and impurity screening

The studies on tungsten (W) sputtering and transport characteristics on EAST tokamak under resonant magnetic perturbation (RMP) fields have been performed with the three-dimensional edge transport code EMC3-EIRENE. The estimation of the W sputtering flux has been carried out based on EMC3-EIRENE modeling for RMP and no RMP applications. The W sputtering flux shows a small difference between RMP and no RMP cases due to weak sensitivity of W sputtering yield on deuterium impact energy for low edge plasma density. However, for high edge plasma density, the strong dependence of W sputtering yield on deuterium impact energy comes into play, which results in a remarkable difference in the W sputtering flux between RMP and no RMP cases. Impacts of the W impurity perpendicular transport on W ions transport have been investigated. With low W perpendicular transport coefficient for RMP case, the edge plasma has a better W ions screening effect for high edge plasma density. The increased W perpendicular transport coefficient results in a good W ions screening effect for both high and low edge plasma densities.