Influence of the normalised ion gyroradius on collisional transport of impurities in full-f gyrokinetic simulations

Obrejan, K.; Idomura, Yasuhiro   ; Honda, Mitsuru*

The use of tungsten in plasma facing components inevitably leads to the pollution of the fusion plasma by heavy impurities and their accumulation at the core, and this phenomenon is not yet fully understood. In this study, we performed a thorough comparison of the impurity particle fluxes between the global gyrokinetic full-f Eulerian code GT5D and local collisional transport theory called as the Hirshman-Sigmar moment approach. It is found that the simulation and the theory agree only in flat temperature profile cases or in large device sizes comparable to ITER. The cause of their discrepancy at the current device sizes is investigated in detail by comparing flows, which drive collisional impurity transport.