Additive manufacturing of steady-state mirrors for the KSTAR ECH launchers

Electron Cyclotron Heating (ECH) launchers typically use a fixed and a steerable mirror to direct a microwave beam to a small volume of a plasma, for the purpose of heating or current drive. Superconducting tokamaks such as KSTAR are now operating their ECH systems at pulse lengths that require steady-state equilibrium between heat input and heat extraction. Princeton Plasma Physics Laboratory has designed, and fabricated, a set of fixed and steerable mirrors for use in the KSTAR system during the 2015 campaign. During the course of our design work, the emergence of additive manufacturing, or 3-D printing, of metal components prompted a decision to take advantage of this technology in our mirrors.