Demonstration of the technique of central lower hybrid heating of high-density plasma at the FT-2 tokamak

The method of central low-hybrid heating of the ion component of dense tokamak plasma based on theoretical concepts has been experimentally demonstrated. The experiments were performed on the FT-2 tokamak, a compact tokamak with a large aspect ratio and a strong toroidal magnetic field $B_T\le$ 3.5 (large toroidal radius $R$ = 0.55 m, small $a$ = 0.08 m). The maximum increase in ion temperature from $T_i(0)$ = 200 to 500–600 eV as a result of additional central low-hybrid heating ($f_0$ = 920 MHz, $P_{\mathrm{RF}}$ = 100 kW) was obtained in deuterium plasma at a reduced the value of $B_T$ = 1.7–1.9 T