Neutral-Beam-Heating Results from the Princeton Large Torus

Experimental results from high-power neutral-beam-injection experiments on the Princeton Large Torus tokamak are reported. At the highest beam powers (2.4 MW) and lowest plasma densities [${n}_{e}(0)=5\ifmmode\times\else\texttimes\fi{}{10}^{13}$ ${\mathrm{cm}}^{\ensuremath{-}3}$], ion temperatures of 6.5 keV are achieved. The ion collisionality ${{\ensuremath{\nu}}_{i}}^{*}$ drops below 0.1 over much of the radial profile. Electron heating of $\frac{\ensuremath{\Delta}{T}_{e}}{{T}_{e}}\ensuremath{\approx}50%$ has also been observed, consistent with the gross energy-confinement time of the Ohmically heated plasma, but indicative of enhanced electron-energy confinement in the core of the plasma.