Low power measurements on a remote steering upper port launcher mock-up for ITER

The association FOM-Rijnhuizen is developing a plug-in 170 GHz ECW launcher system for use in the upper-ports of ITER, based on the remote steering (RS) principle. The launching system enables up to eight mm-wave beams per port plug to be directed from the feeding waveguides through corrugated square waveguides (≈44 × 44 mm²) inside the port plug to the plasma. A mock-up system has been manufactured, capable of vacuum & high-power short-pulse operation. The transmission line consists of a taper, to launch an HE₁₁ mode in 63.5 mm circular corrugated waveguide. The circular waveguide is used as input for the steering mechanism, housed in a vacuum vessel, which directs the beam under an angle between −12° and 12° into the copper square corrugated waveguide. Antenna patterns from the exit aperture of the square waveguide are scanned using a 3-axis scanner.