System of Ion Cyclotron Plasma Heating in the L-2M Stellarator and Its Use for Preionization of Working Gas

A two-channel ion cyclotron resonance heating system has been produced at the L-2M stellarator for introducing RF radiation with a power of 2 kW into the plasma. This system has been used for preliminary plasma ionization preceding the creation of main plasma in the ohmic heating regime in the L-2M stellarator. It has been demonstrated in the preionization experiments that the loop voltage is reduced by approximately 15% immediately before the breakdown of the working gas. In addition, the generation of runaway electrons is efficiently suppressed by RF radiation in the initial stage of discharge formation. The evidence of this suppression is a tenfold decrease in the intensity of hard X-ray radiation.