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

A.G.A. Verhoeven, W.A. Bongers, A. Bruschi**, S. Cirant**, B.S.Q. Elzendoorn,

G. Gantenbein***, M.F. Graswinckel, R. Heidinger*, W. Kasparek***, O.G. Kruyt,

B. Lamers, B. Piosczyk*, B. Plaum***, D.M.S. Ronden, G. Saibene**** and H. Zohm*****

FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Nieuwegein,

The Netherlands, *FZK, Karlsruhe, **CNR, Milan, ***Univ Stuttgart,

****EFDA, Garching, *****Max-Planck, Garching

e-mail: verhoeven@rijnh.nl www.rijnh.nl

The aim of the mm-wave system to be installed in the ITER upper-port system is to inject Electron Cyclotron Waves (ECW) in the ITER plasma in order to stabilize neoclassical tearing modes (NTM). Each upper-port launcher consists of eight mm-wave lines capable of transmitting high power up to 2 MW at 170 GHz. Within a broadly based EFDA collaboration conducting design and R&D activities in preparation for the construction of an ITER upper port launcher, the FOM institute is leading the mm-wave design activity.

In order to exploit the capability of ECW for localized heating and current drive over a range of plasma radii in ITER, the ECH&CD upper port launcher must have a beam steering capability. To avoid movable mirrors at the plasma-facing end of the launcher, the concept of remote mm-wave beam steering (RS) is used, having a corrugated square waveguide within the launcher and the steerable optic is then placed outside of the first confinement boundary of the vacuum vessel.