Oxygen removal with different cleaning techniques under various wall conditions in HT-7

Oxygen removal with D2-ICR cleanings after oxidation experiment in HT-7

“…After adding He filling to a pressure of 0.14 Pa, the release of CO and O 2 increased again and decreased later. It means that He-ICR cleanings are effective for oxygen removal and high cleaning pressures are beneficial for the removal, similar as that in previous reported [18].…”

“…A few factors would influence on the precision of the analysis, as discussed in the oxidation experiment [14][15][16][17][18]. (1) The complex distribution of temperature of vessel walls, liners and limiters; the hot area of the wall components facing the plasma is about 12 m 2 with a similar area not facing the plasma.…”

“…The effectiveness of several types of oxygen removal techniques, including baking, ion cyclotron resonant discharge cleaning, glow discharge cleaning and disruptive plasma cleaning were investigated on hot walls of 402-470 K in the HT-7 machine [18]. Oxygen removal from 'clean' walls and from walls with oxygen contamination has been examined.…”

Plasma recovery after various events in HT-7 superconducting tokamak

“…For better plasma recovery, effective cleanings would be also very important, which could be done by baking, GDC and ICRF cleanings [18]. In HT-7, to remove the retained oxygen from the walls, both He-ICRF and He-GDC were found to be effective.…”

Design and application of GDC on EAST Tokamak

“…The metallic atoms, sputtering redeposit atoms and metal-oxide atoms which have been produced by the interaction of the plasma with walls and limiter are left loosely on the wall surface and have a much higher sputtering yield and vaporization rate [4][5][6][7].…”