Progress of high power and long-pulse dual-frequency ECH system in KSTAR

ECH (Electron Cyclotron Heating) system for KSTAR (Korea Superconducting Tokamak Advanced Research) is composed of two dual-frequency gyrotrons, each generating 950kW of RF power at 140 GHz and 800kW of RF power at 105 GHz. EC system will be installed up to 6 gyrotrons. RF power generated by gyrotron is transmitted to antenna system. The distance of transmission line (TL) from output window of the gyrotron to the launcher is about 70m or more. TL system is composed of 63.5mm corrugated waveguides and several miter bends. The antenna for the EC system consists of two single ports and two dual ports. In this paper, we will describe the EC system currently installed in KSTAR and explain its future plans.