Ion cyclotron conditioning with strong magnetic field in LHD

In order to choose the best conditioning methods to remove hydrogen or tritium from the wall, the ion cyclotron conditioning (ICC) has been tested in fusion devices. The ICC is operated under strong magnetic fields of a few tesla and it is one of the important potential methods for future devices with superconducting coils, such as ITER. The successful initiations of ICC in TEXTOR, Tore Supra, HT-7, AUG, W7-AS and JET using standard ICRF antennas demonstrate the feasibility of this alternative technique. In the large helical device (LHD), which is a current-less steady-state helical device with all superconducting coils, a new conditioning method, the ICC has been started in 2005. An initial experiment of long-term ICC during a strong magnetic field was successfully carried out in LHD. The removal rate depends on the wide energy distributions of high-energy particles accelerated by ICRF power, and controlling this distribution is also important.