Plasma convection in the poloidal limiter shadow of a tokamak

Plasma flow in the poloidal limiter shadow of a tokamak is examined. It is shown that, as a result of contact with a limiter, a large poloidal electric field is created in the plasma. Plasma drift in this field can be considered as anomalous diffusion. The characteristic dimension of the change in plasma density is found to be of the order of the ion cyclotron radius calculated for a poloidal magnetic field. The plasma flow is non-ambipolar and the electric current closes its circuit via the limiter. The results obtained are confirmed by experiments on various tokamaks.