Design of a Launcher for the 105-GHz ECRH System on J-TEXT

To enhance parameters of the plasma and improve the magnetic confinement performance, a 105-GHz electron cyclotron resonance heating (ECRH) system is being built on the J-TEXT. We designed a quasi-optical launcher which mainly consists of a focusing mirror and a steering mirror. The focusing mirror is optimized by considering the localized deposition, and the steering mirror is close to the plasma boundary for flexible adjustment of the toroidal and poloidal injection angles of the wave. The toroidal and poloidal rotation angles of the steering mirror are independently controlled by the mechanical structure. For our design, the beam radius at the plasma center for perpendicular incidence is about 20 mm; the adjustable range of the toroidal and poloidal injection angles is ±14° and ±31°, respectively. These can meet the requirements for physics experiments on J-TEXT.