Edge plasma control using an LID configuration on CHS

Technical Report · Tue Jul 01 04:00:00 EDT 1997

DOI:https://doi.org/10.2172/634041· OSTI ID:634041

Masuzaki, S; Komori, A; Morisaki, T ^[1]

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1. National Inst. for Fusion Science, Oroshi, Toki (Japan); and others

A Local Island Divertor (LID) has been proposed to enhance energy confinement through neutral particle control. For the case of the Large Helical Device (LHD), the separatrix of an m/n = 1/1 magnetic island, formed at the edge region, will be utilized as a divertor configuration. The divertor head is inserted in the island, and the island separatrix provides connection between the edge plasma region surrounding the core plasma and the back plate of the divertor head through the field lines. The particle flux and associated heat flux from the core plasma strike the back plate of the divertor head, and thus particle recycling is localized in this region. A pumping duct covers the divertor head to form a closed divertor system for efficient particle exhaust. The advantages of the LID are ease of hydrogen pumping because of the localized particle recycling and avoidance of the high heat load that would be localized on the leading edge of the divertor head. With efficient pumping, the neutral pressure in the edge plasma region will be reduced, and hence the edge plasma temperature will be higher, hopefully leading to a better core confinement region. A LID configuration experiment was done on the Compact Helical System (CHS) to confirm the effect of the LID. The typical effects of the LID configuration on the core plasma are reduction of the line averaged density to a half, and small or no reduction of the stored energy. In this contribution, the experimental results which were obtained in edge plasma control experiments with the LID configuration in the CHS are presented.

• Research Organization: Oak Ridge National Lab., Fusion Energy Div., TN (United States)
• Sponsoring Organization: USDOE Office of Energy Research, Washington, DC (United States)
• DOE Contract Number: AC05-96OR22464
• OSTI ID: 634041
• Report Number(s): CONF-9706131--22; ON: DE97008557
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CHS TORSATRON
CONFIGURATION
DIVERTORS
EXPERIMENTAL DATA
MAGNETIC FIELD CONFIGURATIONS
PLASMA DENSITY
PLASMA DIAGNOSTICS