Toroidal Plasma Current Startup and Sustainment by RF in the WT-3 Tokamak

Abstract

The toroidal plasma current is started up by rf power alone and is ramped up to above 20 kA in a low density plasma. The fraction ε_R of injected LHW power is converted into poloidal magnetic field energy and its maximum value is about 5 %. For high density cases, a quasi-steady state discharge is obtained and the figure of merit η_CD for steady current drive by LHW is about 0.04 × 10¹⁹ (A·m^-2/W). The direct loss of fast electrons from the plasma is very large and results in the low ε_R and η_CD in our experiments.