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

• DOI: 10.1063/1.3592519
• Publication Date: 2011-05-26T23:00:59Z
• Authors: J. M. Canik; R. Maingi; S. Kubota; Y. Ren; R. E. Bell; J. D. Callen; W. Guttenfelder; H. W. Kugel; B. P. LeBlanc; T. H. Osborne; V. A. Soukhanovskii
• Keywords: 0103 physical sciences; 01 natural sciences

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