Edge transport and turbulence reduction with lithium coated plasma facing components in the National Spherical Torus Experiment

Journal Article · Sun May 15 00:00:00 EDT 2011 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3592519· OSTI ID:21537881

Canik, J M; Maingi, R ^[1]; Kubota, S ^[2]; Ren, Y; Bell, R E; Guttenfelder, W; Kugel, H W; LeBlanc, B P ^[3]; Callen, J D ^[4]; Osborne, T H ^[5]; Soukhanovskii, V A ^[6]

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1. Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
2. University of California-Los Angeles, Los Angeles, California 90095 (United States)
3. Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)
4. University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)
5. General Atomics, San Diego, California 92186 (United States)
6. Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

The coating of plasma facing components (PFCs) with lithium improves energy confinement and eliminates ELMs in the National Spherical Torus Experiment, the latter due to a relaxation of the density and pressure profiles that reduces the drive for peeling-ballooning modes. 2-D interpretive transport modeling of discharges without and with lithium shows that a reduction in the PFC recycling coefficient from R {approx} 0.98 to R {approx} 0.90 is required to match the drop in D{sub {alpha}} emission with lithium coatings. A broadening of the edge barrier region showing reduced transport coefficients is observed, with a {approx}75% drop of the D and {chi}{sub e} from 0.8 < {psi}{sub N} < 0.93 needed to match the profile relaxation with lithium coatings. Turbulence measurements using an edge reflectometry system as well as high-k microwave scattering show a decrease in density fluctuations with lithium coatings. These transport changes allow the realization of very wide pedestals, with a {approx}100% width increase relative to the reference discharges.

• OSTI ID: 21537881
• Journal Information: Physics of Plasmas, Vol. 18, Issue 5; Other Information: DOI: 10.1063/1.3592519; (c) 2011 American Institute of Physics; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BALLOONING INSTABILITY
BOUNDARY LAYERS
COATINGS
EDGE LOCALIZED MODES
FIRST WALL
LITHIUM
NSTX DEVICE
PLASMA CONFINEMENT
PLASMA DIAGNOSTICS
PLASMA PRESSURE
THERMONUCLEAR REACTOR MATERIALS
TURBULENCE
WALL EFFECTS
ALKALI METALS
CLOSED PLASMA DEVICES
CONFINEMENT
ELEMENTS
INSTABILITY
LAYERS
MATERIALS
METALS
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
SPHEROMAK DEVICES
THERMONUCLEAR DEVICES
THERMONUCLEAR REACTOR WALLS
TOKAMAK DEVICES