Zero-Turbulence Manifold in a Toroidal Plasma
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Highcock-2012-Zero-Turbulence Manifold in a Toroidal Plasma.pdf
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Author(s)
Highcock, E. G.
Schekochihin, A. A.
Cowley, S. C.
Barnes, Michael
Parra Diaz, Felix Ignacio
Roach, C. M.
Dorland, W.
Date Issued
December 2012
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Highcock, E. G. et al. “Zero-Turbulence Manifold in a Toroidal Plasma.” Physical Review Letters 109.26 (2012): n. pag. CrossRef. © 2012 American Physical Society
Version
Final published version
Abstract
Sheared toroidal flows can cause bifurcations to zero-turbulent-transport states in tokamak plasmas. The maximum temperature gradients that can be reached are limited by subcritical turbulence driven by the parallel velocity gradient. Here it is shown that q/ϵ (magnetic field pitch/inverse aspect ratio) is a critical control parameter for sheared tokamak turbulence. By reducing q/ϵ, far higher temperature gradients can be achieved without triggering turbulence, in some instances comparable to those found experimentally in transport barriers. The zero-turbulence manifold is mapped out, in the zero-magnetic-shear limit, over the parameter space (γ[subscript E], q/ϵ, R/L[subscript T]), where γ[subscript E] is the perpendicular flow shear and R/L[subscript T] is the normalized inverse temperature gradient scale. The extent to which it can be constructed from linear theory is discussed.
MIT Department
Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
Massachusetts Institute of Technology. Plasma Science and Fusion Center
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1103/PhysRevLett.109.265001
