How pattern is selected in drift wave turbulence: Role of parallel flow shear

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Abstract

The role of parallel shear flow in the pattern selection problem in drift wave turbulence is discussed. Patterns of interest here are E × B convective cells, which include poloidally symmetric zonal flows and radially elongated streamers. The competition between zonal flow formation and streamer formation is analyzed in the context of modulational instability analysis, with the parallel flow shear as a parameter. For drift wave turbulence with k∥ρs ≲ O(1) and without parallel flow coupling, zonal flows are preferred structures. While increasing the magnitude of parallel flow shear, streamer growth overcomes zonal flow growth. This is because the self-focusing effect of the modulational instability becomes more effective for streamers through density and parallel velocity modulation. As a consequence, the bursty release of free energy may result as the parallel flow shear increases.

Original languageEnglish
Article number122305
JournalPhysics of Plasmas
Volume24
Issue number12
DOIs
Publication statusPublished - Dec 1 2017

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parallel flow
turbulence
shear
velocity modulation
self focusing
shear flow
free energy
cells

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

Cite this

How pattern is selected in drift wave turbulence : Role of parallel flow shear. / Kosuga, Yusuke.

In: Physics of Plasmas, Vol. 24, No. 12, 122305, 01.12.2017.

Research output: Contribution to journalArticle

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