Investigation on the drives of the poloidal flow in the ohmic and biased electrode experiments

The experimental investigation on the drives of the poloidal flow in KT-5D tokamak are presented. It is found that the poloidal flow is the main contributor to the radial electric field, and the Reynolds stress can drive significant poloidal flows in ohmic discharges. The investigation on the relationship between the radial gradient of Reynolds stress and the poloidal flow in biasing discharges indicates that not only Reynolds stress but also the Lorentz's force can drive the poloidal flow.