Confinement time scaling in TEXT

Abstract

Values of the total energy confinement time tau E are presented for ohmic hydrogen discharges on the TEXT Tokamak, spanning a range of chord-averaged densities of 2.0-8.5*1013 cm-3, plasma currents of 150-400 kA, and toroidal fields of 15-28 kG. At the higher densities tau E exhibits a saturation which corresponds well with a recently proposed scaling law (Goldston, 1984) in which the saturated value is given by an empirical expression for beam-heated limiter discharges with Ptot identical to POH. The relationship between this observed saturation and density-profile widths is addressed.