Current Drive Using Past Waves and Folded-Waveguide Launchers for the ARIES-I Tokamak Reactor^†

Fast waves launched from folded waveguides are proposed as the reference current drive scenario for the ARIES-I tokamak reactor. An RF power of 100 MW at 141 MHz is launched from above the plasma midplane on the outboard side to drive the required 3.3 MA seed current in the core. The entire coupler system is compact, consisting of two poloidally stacked 12-waveguide toroidal arrays with a directivity of >95% and a coupling efficiency of ∼97%. Recent waveguide experiments on RFTF confirmed the high power capability (∼40 MW/m²), and the better coupling and spectrum shaping properties than those of loops. A definitive demonstration experiment on a tokamak is needed.