High power experiments of remote steering launcher for electron cyclotron heating and current drive

Takahashi, Koji; Moeller, C. P.*; Sakamoto, Keishi; Hayashi, Kenichi*; Imai, Tsuyoshi

High power radiation experiments of a remote steering launcher for an EC H&CD system were carried out to study the characteristic of the rf beam steering and transmission. The remote steering launcher consists of a 4.632m corrugated square waveguide (45.7 45.7mm) and a movable flat mirror which is placed at the input of the waveguide. Measurements were made in the range 0-10 at a frequency of 170GHz. The measured radiation pattern is clearly a Gaussian-like distribution, which is in agreement with the low power measurements. A steering capability of up to 10 was experimentally confirmed. Transmission and radiation of 0.5 MW-3.0 sec and 0.2 MW-10.0 sec pulses were successfully demonstrated over a steering angle range of 0-10. No arcing was observed during the experiments and no damage to the waveguide was found after the experiments were finished. We confirmed that remote steering was a possibly alternative scheme of rf beam steering for EC H&CD.