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 [$n_e\mathrm{}\left(0\right)=5\mathrm{}\times {10}^{13}$ ${\mathrm{cm}}^{-3\mathrm{}}$], ion temperatures of 6.5 keV are achieved. The ion collisionality ${{\nu }_i}^{*}$ drops below 0.1 over much of the radial profile. Electron heating of $\frac{\Delta T_e}{T_e}\approx 50\%$ 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.