Abstract
Various methods are used for wall conditioning of the vacuum chamber of magnetic fusion devices. Among them, direct current glow discharges in deuterium or helium are used to control the contamination of the plasma by impurities coming from the walls. However, the relatively high energy of the ions on the plasma facing components and the difficulty to extend the glow discharge in remote areas could reduce their attractiveness. We present the results from tests performed in a dedicated reactor, equipped with a narrow cylindrical duct with seven Langmuir probes. A heated cathode, biased at -40 Volts with respect to the walls, is placed inside the duct. The influence of the pressure on the penetration of the discharge into the tube is shown and discussed. Significant values of ion current and potential in the tube are obtained for pressures two orders of magnitude higher than those currently used in present Tokamaks. The effect of establishing the glow discharge between the anode and the heated cathode was studied. The heated cathode currents can be tuned in such a way that the current measured by the probe increases whereas the potential drop between the glow discharge and the wall decreases and the energy of the ions which are impinging onto the surfaces is reduced.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.