Experimental results of MHD suppression with modulated LHCD on the HT-7 tokamak

Modulation of lower hybrid current drive was used successfully to suppress MHD activity. This was achieved in discharges with MHD m = 2 tearing modes during the discharge conditions I-p = 110 kA, B-t = 1.75 T, (n) over bar (e0) similar to 1.1 x 10(13) cm(-3). The delivering time of LHCD pulse is less then 30 mu s. The amplitude, interval and the period of LHCD modulation pulse can be adjusted very conveniently. The modulation LHCD can be delivered very fast at any time during the discharge. The modulation LHCD period was always much shorter than the plasma resistive time (tau(eta) approximate to 100 ms). So the profile of plasma current is changed much faster than the plasma resistive time. The different forms of LHCD modulating can be proved.