Current rise assisted by lower hydrid waves on Petula-B

On the basis of the experimental results on Lower Hybrid Current Drive studies, it appears that the best efficiency of this non-inductive method is obtained in Tokamak discharges operating at low density and with a parallel DC electric field. These conditions are fulfilled when both lower hybrid waves and ohmic heating transformer are used to ramp-up the plasma current. In this paper, we present the results of such a scenario which has been carried out on Petula-B (R = 0.72 m, a = 0.17 m) by means of 1.3 GHz or 3.7 GHz RF system. For the purpose of these studies, plasma current or loop voltage are successively feedback controlled