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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.

Additional information

Authors: DOUAI D, Département de Recherches sur la Fusion Contrôlée, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR);GARNIER D, Département de Recherches sur la Fusion Contrôlée, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR);BRÉMOND S, Département de Recherches sur la Fusion Contrôlée, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR);GRISOLIA C, Département de Recherches sur la Fusion Contrôlée, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR);BUCALOSSI J, Département de Recherches sur la Fusion Contrôlée, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR);SHIGIN P, Plasma Physics Department, Moscow Engineering and Physics Institute, Moscow (RU);BEGRAMBEKOV L, Plasma Physics Department, Moscow Engineering and Physics Institute, Moscow (RU)
Bibliographic Reference: An article published in: Journal of Physics: Conference Series 100 (2008), 5 pp.
Availability: This article can be accessed online by subscribers, and can be ordered online by non-subscribers, at: http://dx.doi.org/doi:10.1088/1742-6596/100/6/062034
Record Number: 200819872 / Last updated on: 2008-06-24
Category: PUBLICATION
Original language: en
Available languages: en
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