Experiments on stabilization of resonant fast magnetosonic wave pumping in a TO-2 tokamak with ion-cyclotron heating

Conversion of a fast magnetosonic (FMS) wave, excited from the direction of the weak toroidal magnetic field, into a plasma wave (ion Bernstein wave) close to ion-ion hybrid resonance is investigated in the TO-2 tokamak with a deuterium plasma containing a 15-20% hydrogen impurity. Damping of the FMS wave was found to occur only after many passes, and pumping resonances were observed with a Q-factor of 40-50. Trapping and automatic tracking of the pumping resonance owing to stabilization of the plasma density at the natural frequency of the plasma resonator was observed. This effect arises because the fast particles accelerated in the resonant field of the FMS wave interact with the walls of the chamber and limiter, increasing the discharge of the working gas there. Significant electron heating was recorded while tracking pumping resonance in the wave conversion regime: Prf ≅ kW, Δ < Te0> = 700, ΔTi = 40 eV, bar ne = 1.5 x 1013 cm-3, η = 4.5 - 5.0 eVxcm-3/kW