AbstractFast waves in the ion cyclotron range of frequencies are proposed as the reference current driver for the ARIES-I conceptual tokamak power reactor. An RF power of 100 MW at 141 MHz is launched from above the plasma outboard midplane to drive the required 3.3 MA seed current in the core. Folded waveguides are used as wave launchers because of their observed higher power-handling capability compared to loops, and compact and robust structure. The wave guide will be made of silicon-carbide matrix composite material embedded with copper near the surface, in order to take advantage of its favorable safety and environmental features. 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%. The RF current-drive system uses primarily technologies that require a reasonably modest development program to reach its projected efficiency of 71% in 30–40 years.