Neutral-Beam Current-Driven High-Poloidal-Beta Operation of the DIII-D Tokamak

Abstract

Neutral-beam current-drive experiments in the DIII-D tokamak with a single null poloidal divertor are described. A plasma current of 0.34 MA has been sustained by neutral beams alone, and the energy confinement is of $H$-mode quality. Poloidal $\ensuremath{\beta}$ values reach 3.5 without disruption or coherent magnetic activity suggesting that these plasmas may be entering the second stability regime.