Edge Turbulence Velocity Changes with Lithium Coating on NSTX
Authors: A. Cao, S.J. Zweben, D.P. Stotler, M. Bell, A. Diallo, S.M. Kaye and B. LeBlanc
Abstract:
Lithium coating improves energy confinement and eliminates edge localized
modes in NSTX, but the mechanism of this improvement is not yet well understood. We
used the gas-puff-imaging (GPI) diagnostic on NSTX to measure the changes in edge
turbulence which occurred during a scan with variable lithium wall coating, in order to
help understand the reason for the confinement improvement with lithium. There was a
small increase in the edge turbulence poloidal velocity and a decrease in the poloidal
velocity fluctuation level with increased lithium. The possible effect of varying edge
neutral density on turbulence damping was evaluated for these cases in NSTX.
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Submitted to: Plasma Physics and Controlled Fusion (July 2012)
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Download PPPL-4789 (pdf 2 MB 16 pp)
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