Design of the mm-wave system of the ITER ECRH upper launcher

The design work for the ITER ECRH remote-steering upper-port launcher is described. The goal of the system is the stabilization of neoclassical tearing modes (NTMs). The required scanning range in the plasma (more than 20°) is achieved remotely, far away from the hostile plasma environment. This is done behind a diamond window in a separate vacuum environment. Scanning of the beam is done by a mirror that both rotates and translates to steer the beam in the proper way through the window and an isolation valve into a square corrugated waveguide. At the output of this 4.4 m long waveguide, the beam comes out at the same angle and is reflected by a fixed front mirror into the plasma [A.G.A. Verhoeven, et al., The ITER remote-steering ECW upper-port launcher, in: N. Hiromoto (Ed.), The 28th International Conference on Infrared and MM Waves, Otsu, Japan, September 29–October 3, 2003 (JSAP Catalog No. 031231)].