Development of steady-state mirrors for the KSTAR ECH launchers

Steerable Electron Cyclotron Heating (ECH) launchers typically use a fixed, focusing mirror and a flat steerable mirror to direct a high power beam. The launchers presently in service on KSTAR are intended for use in pulsed operation and are passively cooled. KSTAR, and its ECH system, will eventually operate at pulse lengths where a steady-state balance between input power and heat removal must be achieved. Initial design studies for ECH launcher mirrors have been performed, and a prototype has been fabricated and tested. This paper describes the design studies for steady-state ECH launcher mirrors considered for the KSTAR system. Results of analyses and prototype tests are described.