verhoeven@rijnh.nl
The coordination of the design of the
mm-wave system to be installed in the ITER Upper Ports is being carried out at
the FOM institute. The aim of the 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.
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.
The steerable optic is considered a critical component for the ECH&CD
system since it is subject to nuclear, radiative, particle, and Ohmic thermal
loads and hence must be cooled during plasma operation. 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.