Experimental confirmation of self-regulating turbulence paradigm in two-dimensional spectral condensation

L. Bardóczi, A. Bencze, M. Berta, and L. Schmitz
Phys. Rev. E 90, 063103 – Published 3 December 2014

Abstract

Turbulent transport in magnetic fusion plasmas can be significantly suppressed by Reynolds-stress-induced zonal flows, allowing effective plasma confinement. We present experimental evidence of spatiotemporal correlation between small-scale turbulence-induced Reynolds stress and large-scale zonal flow production in the E×B driven hydrodynamic spectral condensation. We show that Reynolds stress is generated effectively by anisotropic vorticity structures possessing collective tilt angle. The maximum amplitude of the tilt, the Reynolds stress, and the mean zonal flow production coincide with the transition time of the velocity field, indicating a key role of turbulence-induced Reynolds stress in the condensation of the flow. The analysis of the energy transfer between turbulence and zonal flow shows coherent oscillations with π/2 phase delay, thus indicating a predator-prey-like interaction between zonal flow and turbulence.

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  • Received 13 November 2013
  • Revised 17 May 2014

DOI:https://doi.org/10.1103/PhysRevE.90.063103

©2014 American Physical Society

Authors & Affiliations

L. Bardóczi1, A. Bencze2, M. Berta3,4, and L. Schmitz1

  • 1University of California, Los Angeles, Los Angeles, California 90095, USA
  • 2Wigner RCP, EURATOM Association, 1121 Budapest, Hungary
  • 3Széchenyi István University, EURATOM Association, 9026 Győr, Hungary
  • 4Institute of Plasma Physics AS CR, v.v.i., 18200 Prague, Czech Republic

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Issue

Vol. 90, Iss. 6 — December 2014

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