Development of a full scale ECRH mm-wave launching system mock-up for ITER

Abstract

An ECRH (electron cyclotron resonance heating) launching system (Fig. 1) for the ITER upper ports is being designed. 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 beam lines capable of transmitting high power up to 2 MW at 170 GHz into the plasma. 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 launching system 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 square corrugated waveguide (SCW) located inside the port-plug, which is primary (torus) vacuum. The steerable mirror units are placed outside of the first confinement boundary of the vacuum vessel. FOM is developing a full-scale mm-wave launching system mock-up. The mock-up consists of a launching system in a set of vacuum vessels, in order to provide the most ITER-like operation conditions. The mock-up will first be used at the FOM institute in The Netherlands to test the launching system at low power. In 2005, tests will be done in Karlsruhe at high power and short pulses. The mock-up will be shipped again to The Netherlands after the tests in Karlsruhe to prepare it for the Lausanne 2 MW, cw tests.