Fluxdriven simulations of turbulence collapse
Abstract
Using threedimensional nonlinear simulations of tokamak turbulence, we show that an edge transport barrier (ETB) forms naturally once input power exceeds a threshold value. Profiles, turbulencedriven flows, and neoclassical coefficients are evolved selfconsistently. A slow power rampup simulation shows that ETB transition is triggered by the turbulencedriven flows via an intermediate phase which involves coherent oscillation of turbulence intensity and E×B flow shear. A novel observation of the evolution is that the turbulence collapses and the ETB transition begins when R{sub T} > 1 at t = t{sub R} (R{sub T}: normalized Reynolds power), while the conventional transition criterion (ω{sub E×B}>γ{sub lin} where ω{sub E×B} denotes mean flow shear) is satisfied only after t = t{sub C} ( >t{sub R}), when the mean flow shear grows due to positive feedback.
 Authors:
 National Fusion Research Institute, Daejeon 305333 (Korea, Republic of)
 (United States)
 Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)
 Publication Date:
 OSTI Identifier:
 22408206
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; EDGE LOCALIZED MODES; ELECTRIC FIELDS; MAGNETIC FIELDS; NEOCLASSICAL TRANSPORT THEORY; NONLINEAR PROBLEMS; OSCILLATIONS; REYNOLDS NUMBER; SHEAR; SIMULATION; THREEDIMENSIONAL CALCULATIONS; TOKAMAK DEVICES; TURBULENCE
Citation Formats
Park, G. Y., Kim, S. S., Jhang, Hogun, Rhee, T., Diamond, P. H., CASS and Department of Physics, University of California, San Diego, La Jolla, California 920930429, and Xu, X. Q. Fluxdriven simulations of turbulence collapse. United States: N. p., 2015.
Web. doi:10.1063/1.4914841.
Park, G. Y., Kim, S. S., Jhang, Hogun, Rhee, T., Diamond, P. H., CASS and Department of Physics, University of California, San Diego, La Jolla, California 920930429, & Xu, X. Q. Fluxdriven simulations of turbulence collapse. United States. doi:10.1063/1.4914841.
Park, G. Y., Kim, S. S., Jhang, Hogun, Rhee, T., Diamond, P. H., CASS and Department of Physics, University of California, San Diego, La Jolla, California 920930429, and Xu, X. Q. 2015.
"Fluxdriven simulations of turbulence collapse". United States.
doi:10.1063/1.4914841.
@article{osti_22408206,
title = {Fluxdriven simulations of turbulence collapse},
author = {Park, G. Y. and Kim, S. S. and Jhang, Hogun and Rhee, T. and Diamond, P. H. and CASS and Department of Physics, University of California, San Diego, La Jolla, California 920930429 and Xu, X. Q.},
abstractNote = {Using threedimensional nonlinear simulations of tokamak turbulence, we show that an edge transport barrier (ETB) forms naturally once input power exceeds a threshold value. Profiles, turbulencedriven flows, and neoclassical coefficients are evolved selfconsistently. A slow power rampup simulation shows that ETB transition is triggered by the turbulencedriven flows via an intermediate phase which involves coherent oscillation of turbulence intensity and E×B flow shear. A novel observation of the evolution is that the turbulence collapses and the ETB transition begins when R{sub T} > 1 at t = t{sub R} (R{sub T}: normalized Reynolds power), while the conventional transition criterion (ω{sub E×B}>γ{sub lin} where ω{sub E×B} denotes mean flow shear) is satisfied only after t = t{sub C} ( >t{sub R}), when the mean flow shear grows due to positive feedback.},
doi = {10.1063/1.4914841},
journal = {Physics of Plasmas},
number = 3,
volume = 22,
place = {United States},
year = 2015,
month = 3
}

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