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 degrees) 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. 03123 1)]. (c) 2005 Elsevier B.V. All rights reserved.