Numerical study of neoclassical impurity transport using the code GT5D

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

The numerical accuracy of the gyrokinetic full-f Eulerian code GT5D is studied with respect to collisional or neoclassical transport of heavy impurity ions such as tungsten. Collisional transport of tungsten is determined by its collisional interaction with fuel ions such as deuterium and tritium. Because of the extreme mass ratio between deuterium and tungsten, the collision operator becomes a multi-scale problem in velocity space. In this work, numerical convergence of the collision operator is examined by estimating friction matrix elements, and numerical resolution needed for recovering collisional transport theory of heavy impurity ions clarified.