Stabilization of Toroidal Currents in High-βPlasmas by Surface Magnetic Fields

Without the imposition of a toroidal magnetic field, a toroidal plasma current is sustained whose maximum current density increases linearly with the applied poloidal surface magnetic field strength. Both plasma compression and heating are observed in the main weak-field region, and average $\beta \approx 6\%$ and energy confinement time $\tau =1\mathrm{}$ msec have been achieved. This concept significantly increases the $\beta$ values and the allowable current in toroidal, Ohmically heated plasmas.