Improved Unlike-Particle Collision Operator for delta-f Drift-Kinetic Particle Simulations

Plasmas in modern tokamak experiments contain a significant fraction of impurity ion species in addition to main deuterium background.A new unlike-particle collision operator forδf particle simulation has been developed to study the nonlocal effects of impurities due to finite ion orbits on neoclassical transport in toroidal plasmas.A new algorithm for simulation of cross-collisions between different ion species includes test-particle and conserving field-particle operators.An improved field-particle operator is designed to exactly enforce conservation of number,momentum and energy.