A New Wall Conditioning Technique Developed on the HT-7 Superconducting Tokamak with a Permanent Magnetic Field

A new technique for wall conditioning with a permanent magnetic field has been tested and developed on the HT-7 superconducting tokamak by ion cyclotron range frequency wave injection. The operation ranges for conditioning and recycling was investigated with different working gas (D₂, He), toroidal field (0.1-2.5 T) and rf powers. The experimental results show that its cleaning efficiency is about three times higher than that of glow discharge cleaning. This new technique has been used daily during experiments.