Ion-Bernstein-Wave Heating in the JIPPT-II-U Tokamak Plasma

Ion-Bernstein-wave heating is investigated in the JIPPT-II-U tokamak plasma, ${\overline{n}}_e\simeq 1.5\times {10}^{13}$ ${\mathrm{cm}}^{-3\mathrm{}}$, $T_{e0\mathrm{}}\simeq 700$ eV, and $T_{i0\mathrm{}}\simeq 300$ eV for $P_{\mathrm{rf}}\lesssim 100$ kW. When the $\frac{3}{2}{\Omega }_{\mathrm{H}}$ layer is placed near the plasma minor axis, the bulk-hydrogen-ion temperature shows a significant rise, $\Delta T_{i\perp }<~700$ eV and $\Delta T_{i\parallel }<~300$ eV. The ion-heating dependence on the magnetic field and rf power suggests a presence of a direct bulk-hydrogen heating mechanism at $\omega \simeq \frac{3}{2}{\Omega }_{\mathrm{H}}$.