Scaling of confinement with major and minor radius in the Tokamak Fusion Test Reactor.

Abstract

Plasma-size scans have been performed in the Tokamak Fusion Test Reactor to investigate the effect of major and minor radius upon energy confinement in high-recycling plasmas heated by neutral-beam injection. The major radius, minor radius, and aspect ratio were varied over a large range ({ital a}=0.4--0.9 m, {ital R}=2.08--3.2 m, {ital R}/{ital a}=2.8--8.0). The energy confinement measured with diamagnetic and kinetic diagnostics scales strongly with major radius, and weakly or negatively with minor radius.