Direct measurement of fast magneto-sonic wave near the ion-ion hybrid resonance layer by magnetic probes

Abstract

Direct measurement of the fast magnetosonic wave near the hybrid resonance layer in a deuterium-hydrogen plasma by magnetic probes is described. Externally driven waves in the ion cyclotron range of frequencies (ICRF) are excited by a half-turn antenna located on the high-field side in the TNT-A tokamak. The amplitude and the phase shift of the fast magnetosonic wave are measured by magnetic probes in the equatorial plane of the plasma. The amplitude of the fast magnetosonic wave is damped in the ion-ion hybrid resonance layer, and the wavelength changes at the high-field side near this layer. The amplitude and the phase shift of the wave as measured by the probes agree with those calculated from a cold-slab model.