Turbulent and neoclassical impurity transport in tokamak plasmas

Impurity particle transport in tokamaks is studied using an electrostatic fluid model for main ion andimpurity temperature gradient (ITG)͒ mode and trapped electron (TE͒) mode turbulence in thecollisionless limit and neoclassical theory. The impurity flux and impurity density peaking factorobtained from a self-consistent treatment of impurity transport are compared and contrasted with theresults of the often used trace impurity approximation. Comparisons between trace andself-consistent turbulent impurity transport are performed for ITER-like profiles. It is shown that forsmall impurity concentrations the trace impurity limit is adequate if the plasma is dominated by ITGturbulence. However, in case of TE mode dominated plasmas the contribution from impurity modesmay be significant, and therefore a self-consistent treatment may be needed