Wall conditioning towards the utilization in ITER

Wall conditioning provides an effective means for reducing both impurities and recycling from the plasma surrounding surface. A wide variety of techniques have been developed during the last few decades for conditioning the plasma facing surface. With the presence of magnetic fields, electron cyclotron resonant (ECR) and ion cyclotron resonant (ICR) discharge cleaning techniques have been explored, which could be used for next generation superconducting magnetic confined devices, such as ITER. Efforts have been made on the application of ICR conditioning on many devices and significant progress has been made. A new and simple method for future wall conditioning, high frequency glow discharge cleaning (HF-GDC), has been developed. HF-GDC operates in the presence of strong magnetic field (0.5-2 T) at frequencies of 20-100 kHz stably for a wide range of gas pressures. In this paper, all these techniques are reviewed and their proper application in ITER are discussed.