Random shearing by zonal flows and transport reduction

Eun Jin Kim, P. H. Diamond

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

The physics of random shearing by zonal flows and the consequent reduction of scalar field transport are studied. In contrast to mean shear flows, zonal flows have a finite autocorrelation time and can exhibit complex spatial structure. A random zonal flow with a finite correlation time τ ZF decorrelates two nearby fluid elements less efficiently than a mean shear flow does. The decorrelation time is τ D=(τ ηZFΩ 2 rms) 1/2n is the turbulent scattering time, and Ω rms is the rms shear), leading to larger scalar field amplitude with a slightly different scaling (∝τ Drms), as compared to the case of coherent shearing. In the strong shear limit, the flux scales as ∝Ω rms -1.

Original languageEnglish
JournalPhysics of Plasmas
Volume11
Issue number12
DOIs
Publication statusPublished - 29 Oct 2004
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics

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