Effects of High-Power Ion Bernstein Waves on a Tokamak Plasma

Effects of high-power ion-Bernstein-wave heating on the PLT tokamak plasmas have been investigated with up to 650 kW of rf power coupled to the plasma. A significant improvement in the deuterium particle confinement (as much as 300%) during high-power ion-Bernstein-wave heating has been observed. Associated with it, a longer injected-impurity-confinement time, reduced drift-wave turbulence activity, frequency shifts of drift-wave turbulence, and development of a large negative edge potential were observed. The ion heating efficiency, $\frac{\ensuremath{\Delta}{T}_{i}(0){\overline{n}}_{e}}{{P}_{\mathrm{rf}}}=6\ifmmode\times\else\texttimes\fi{}{10}^{13}$ eV ${\mathrm{cm}}^{\ensuremath{-}3}$/kW, without high-energy tail ions, is relatively constant up to the maximum rf power.