Physics and engineering aspects of the ICRF heating and current drive system on KSTAR

The design of an ICRF heating and current drive system was undertaken as part of the KSTAR (Korea Superconducting Tokamak Advanced Research) design study. ICRF fast wave heating and current drive scenarios are identified and modelled using the full wave code, TORIC which solves the finite Larmor radius wave equations in the ion cyclotron frequency range in an arbitrary axisymmetric toroidal geometry. The characteristics of the fast wave propagation/absorption, power partitions among plasma species, and the driven current/current drive efficiencies are analysed. The ICH/FWCD launcher is designed to have four current straps and each strap, using appropriate tuning, matching, and decoupling circuitry will be driven by an independent 2 MW RF power source. We present the design characteristics of the ICH/FWCD launcher, and the matching and decoupling system. Also, the feasibility of the antenna design to couple the required power to the plasma is demonstrated.