Zero-turbulence manifold in a toroidal plasma

E. G. Highcock, A. A. Schekochihin, S. C. Cowley, M. Barnes, F. I. Parra, C. M. Roach, W. Dorland

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31 Scopus citations


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/Ïμ (magnetic field pitch/inverse aspect ratio) is a critical control parameter for sheared tokamak turbulence. By reducing q/Ïμ, 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 (γE, q/Ïμ, R/LT), where γE is the perpendicular flow shear and R/LT is the normalized inverse temperature gradient scale. The extent to which it can be constructed from linear theory is discussed.

Original languageEnglish (US)
Article number265001
JournalPhysical review letters
Issue number26
StatePublished - Dec 27 2012
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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