Balance of angular momentum and energy in a rotating‐field generated plasma equilibrium

The balance of energy and angular momentum is modeled for a rigid‐rotor plasma equilibrium generated by a rotating magnetic field. The model predicts that deviation from circular polarization of the rotating field and the presence of transverse stationary error fields reduce the efficiency of the diamagnetic current drive. The error field in combination with low collision frequency can prevent electron fluid corotation. In the RACETRACK experiment [Rev. Sci. Instrum. 57, 2720 (1986)], the measured power balance is in agreement with the measured rotating field polarization and the estimated magnitude of the stationary error field.