A QUANTITATIVE INVESTIGATION OF ROTATING MAGNETIC-FIELD CURRENT DRIVE IN A FIELD-REVERSED CONFIGURATION

It is experimentally demonstrated that a Field-Reversed Configuration can be generated and maintained by the rotating magnetic field technique of driving plasma current. For the particular discharge described in this paper, detailed measurements showed that the pressure varied linearly with the poloidal flux function and that the contribution of any ponderomotive force to plasma confinement was negligible. Consequently, the observed plasma/field equilibrium could be adequately described by the Solov'ev solution of the Grad-Shafronov equation. Detailed measurements were made of the amplitude and phase of the rotating magnetic field within the plasma volume. Incomplete penetration of the rotating field into the plasma was observed. Nevertheless, about half the maximum possible amount of driven current was obtained. An appropriate analysis of the experimental data indicated that the standard rotating magnetic field current drive theory (mobile electrons, immobile ions, infinitely long plasma cylinder) was capable of quantitatively describing the current drive mechanism operative in the experiment.