Confinement of angular momentum in divertor and limiter discharges in the Doublet III tokamak

Abstract

Angular momentum confinement has been studied in neutral beam heated limiter and divertor discharges in Doublet III. Scaling of the angular momentum confinement time with plasma current and neutral beam power has been determined. For divertor discharges, the angular momentum confinement time and the energy confinement time are equal and scale in the same way. This suggests that a single mechanism governs the transport of both energy and angular momentum in divertor discharges. For limiter discharges, the angular momentum confinement time is less than the energy confinement time and the scalings are dissimilar. In both limiter and divertor discharges the measured angular rotation speed profiles are consistent with the theoretical prediction that angular rotation speed is a function of the flux surface co-ordinate only and is independent of poloidal angle.