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Title: Turbulence elasticity—A new mechanism for transport barrier dynamics

We present a new, unified model of transport barrier formation in “elastic” drift wave-zonal flow (DW-ZF) turbulence. A new physical quantity—the delay time (i.e., the mixing time for the DW turbulence)—is demonstrated to parameterize each stage of the transport barrier formation. Quantitative predictions for the onset of limit-cycle-oscillation (LCO) among DW and ZF intensities (also denoted as I-mode) and I-mode to high-confinement mode (H-mode) transition are also given. The LCO occurs when the ZF shearing rate (|〈v〉{sub ZF}{sup ′}|) enters the regime Δω{sub k}<|〈V〉{sub ZF}{sup ′}|<τ{sub cr}{sup −1}, where Δω{sub k} is the local turbulence decorrelation rate and τ{sub cr} is the threshold delay time. In the basic predator-prey feedback system, τ{sub cr} is also derived. The I-H transition occurs when |〈V〉{sub E×B}{sup ′}|>τ{sub cr}{sup −1}, where the mean E × B shear flow driven by ion pressure “locks” the DW-ZF system to the H-mode by reducing the delay time below the threshold value.
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [4]
  1. WCI Center for Fusion Theory, NFRI, Daejeon 305-333 (Korea, Republic of)
  2. (United States)
  3. IAS and RIAM, Kyushu University, Kasuga 816-8580 (Japan)
  4. LPP, Ecole Polytechnique, CNRS, Palaiseau Cedex 91128 (France)
Publication Date:
OSTI Identifier:
22303606
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 9; Other Information: (c) 2014 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; CUPRATES; DIFFUSION BARRIERS; H-MODE PLASMA CONFINEMENT; LANTHANUM COMPOUNDS; LIMIT CYCLE; SHEAR; TIME DELAY; TURBULENCE; UNIFIED MODEL; WAVE PROPAGATION