Toroidal Plasma Current Start-Up and Sustainment by rf in the WT-2 Toroidal Device

Abstract

When rf power in the range of lower hybrid frequency was injected into the microwave discharge plasma at the electron cyclotron resonance in the WT-2 toroidal device, the toroidal plasma current is generated, started up to I_p∼5 kA, and sustained by rf power alone, without the Ohmic heating power (so-called rf tokamak). This lower-hybrid-wave driven current is produced only when high-energy tail electrons, which interact resonantly with the lower hybrid wave, are present in the initial electron cyclotron resonance plasma.