On ion flow caused by the inductive electric field in a tokamak

Abstract

It was recently pointed out that the inductive electric field in a tokamak can give rise to toroidal and poloidal plasma rotation comparable to that sometimes observed in experiments. Here it is shown that the flow velocity of heavy impurity ions, which is normally what is measured, is lower than that of the bulk plasma for rotation produced in this way. If the bulk ions and electrons are in the banana regime, the impurity rotation is at most about two thirds of the bulk plasma rotation and decreases with increasing effective ion charge (Zeff) and distance from the magnetic axis.