Verification of collision modules for neoclassical simulations in Tokamak*

Collision physics is important to predict transport which influences confinement in Tokamak fusion plasma. In numerical simulations, collision operator should be properly treated to estimate transport quantities reasonably and correctly. In this research, we conducted verification of two grid-based collision modules for Dougherty operator [1, 5] and test particle part of linearized collision operator [2]  against neoclassical physics in Tokamak. The collision modules are incorporated into a new gyro-kinetic continuum code, gKPSP2, based on discontinuous Galerkin method [3]. For these verification exercises, in particular, parameter scans of heat flux and poloidal flow over ν_* are conducted by adjusting density profile. The neoclassical quantities obtained from the simulations are compared against theoretical predictions by Chang-Hinton formula and Sauter formula, respectively [4]. Also, results of cross verification with a gyro-kinetic PIC code will be presented.