Film Deposition and their Removal in Gaps and Regions Shaded from the Plasma in the Presence of RF Fields

The re-deposition of constructional materials inside the chamber of a fusion device is undesirable mainly for increased capture of hydrogen isotopes in the deposited layers. Currently, a variety of methods for wall cleaning from the deposited layers are developed, including a special “cleaning” discharge inside the chamber with an oxygen puff. Special attention is paid to film removal in gaps and regions shaded from the plasma. The study of CH-films deposition and their removal in gaps and regions shaded from the plasma were conducted in the linear simulator with a beam-plasma discharge PR-2 in a mode with automatic generation of high-frequency current oscillations, which ensured the presence of RF fields. High efficiency of cleaning the films in gaps is demonstrated in the discharge in oxygen with the presence of RF fields. The film cleaning rate was up to 1.7 μm for 2 hours.