Design status of EC system in ITER — design of reliable RF beam launching system

The design of two types of EC-launchers which fulfil many functions requested to EC system, is described. One with toroidal RF beam steering is mainly used for main plasma heating and current drive. The other with poloidal RF beam steering is mainly used for neoclassical tearing mode stabilization. The RF beam is deflected by a steerable mirror. In this design, one mirror, steerable in a single direction, is assigned to one row of waveguides. A reliable RF beam launching system can be constructed by using a spiral pipe for cooling water and a simple push/pull shaft for mirror rotation without a cam and link. The design includes a mirror composed of a high melting temperature material plate and a SS pipe.