Direct Measurement of a Toroidally Directed Zonal Flow in a Toroidal Plasma

T. Nishizawa, A. F. Almagri, J. K. Anderson, W. Goodman, M. J. Pueschel, M. D. Nornberg, S. Ohshima, J. S. Sarff, P. W. Terry, Z. R. Williams

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15 Citations (Scopus)


Zonal flow appears in toroidal, magnetically confined plasmas as part of the self-regulated interaction of turbulence and transport processes. For toroidal plasmas having a strong toroidal magnetic field, the zonal flow is predominately poloidally directed. This Letter reports the first observation of a zonal flow that is toroidally directed. The measurements are made just inside the last closed flux surface of reversed field pinch plasmas that have a dominant poloidal magnetic field. A limit cycle oscillation between the strength of the zonal flow and the amplitude of plasma potential fluctuations is observed, which provides evidence for the self-regulation characteristic of drift-wave-type plasma turbulence. The measurements help advance understanding and gyrokinetic modeling of toroidal plasmas in the pursuit of fusion energy.

Original languageEnglish
Article number105001
JournalPhysical review letters
Issue number10
Publication statusPublished - Mar 15 2019
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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