The ITER ECH upper launcher is devoted to directing up to 8 2NM beams per port plug over half of the plasma cross section. A focusing mirror is used to achieve a very narrow deposition profile to stabilize MHD activity such as the neoclassical tearing modes (NTMs) and the sawtooth oscillation. The beam deposition location is changed via a steering mirror with up to +/-7 deg (+/-14 deg beam), which allows access from inside mid radius out to nearly the plasma edge. The steering mechanism uses a frictionless backlash free system to avoid sticking, thus increasing the reliability.
Minh Quang Tran, René Chavan, Hartmut Zohm, Konstantinos Avramidis
Joaquim Loizu Cisquella, Ajay Kumar
Olivier Sauter, Minh Quang Tran, Emiliano Fable, Simon Van Mulders, Hartmut Zohm