ICRF (ion cyclotron range of frequencies) discharge cleaning with a toroidal field and an additional vertical field was carried out on EAST recently. With the injected ICRF power of 10 kW, He pressure of 10−3 Pa, toroidal field of 0.5 T and vertical field of 0.01 T, ICRF plasmas became approximately symmetric in both major radial and vertical directions, and the removal rate of hydrogen increased by 32%. A comparison of ICRF discharge cleaning between stainless steel and graphite walls was carried out, which showed that ICRF plasmas had a similar effect on the first walls of both materials. ICRF discharge cleaning between plasma shots after a major disruption was studied in detail, and it was observed that ICRF discharge cleaning under a toroidal field of 2 T was effective in recovering plasma performance quickly after a major disruption.
ICRF plasma production at hydrogen minority regime in LHD