Turbulent transport and dynamo in sheared magnetohydrodynamics turbulence with a nonuniform magnetic field

Nicolas Leprovost, Eun Jin Kim

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We investigate three-dimensional magnetohydrodynamics turbulence in the presence of velocity and magnetic shear (i.e., with both a large-scale shear flow and a nonuniform magnetic field). By assuming a turbulence driven by an external forcing with both helical and nonhelical spectra, we investigate the combined effect of these two shears on turbulence intensity and turbulent transport represented by turbulent diffusivities (turbulent viscosity, α and β effect) in Reynolds-averaged equations. We show that turbulent transport (turbulent viscosity and diffusivity) is quenched by a strong flow shear and a strong magnetic field. For a weak flow shear, we further show that the magnetic shear increases the turbulence intensity while decreasing the turbulent transport. In the presence of a strong flow shear, the effect of the magnetic shear is found to oppose the effect of flow shear (which reduces turbulence due to shear stabilization) by enhancing turbulence and transport, thereby weakening the strong quenching by flow shear stabilization. In the case of a strong magnetic field (compared to flow shear), magnetic shear increases turbulence intensity and quenches turbulent transport.

Original languageEnglish
Article number026302
JournalPhysical Review E - Statistical, Nonlinear, and Soft Matter Physics
Volume80
Issue number2
DOIs
Publication statusPublished - 5 Aug 2009
Externally publishedYes

Fingerprint

nonuniform magnetic fields
magnetohydrodynamic turbulence
Shear Flow
shear flow
Turbulence
Magnetic Field
turbulence
shear
Diffusivity
diffusivity
Viscosity
Stabilization
stabilization
viscosity
Reynolds equation
Reynolds Equation
Quenching
magnetic fields
Forcing
quenching

ASJC Scopus subject areas

  • Statistical and Nonlinear Physics
  • Statistics and Probability
  • Condensed Matter Physics

Cite this

@article{d573e268aae345148edf2a55ee53d64e,
title = "Turbulent transport and dynamo in sheared magnetohydrodynamics turbulence with a nonuniform magnetic field",
abstract = "We investigate three-dimensional magnetohydrodynamics turbulence in the presence of velocity and magnetic shear (i.e., with both a large-scale shear flow and a nonuniform magnetic field). By assuming a turbulence driven by an external forcing with both helical and nonhelical spectra, we investigate the combined effect of these two shears on turbulence intensity and turbulent transport represented by turbulent diffusivities (turbulent viscosity, α and β effect) in Reynolds-averaged equations. We show that turbulent transport (turbulent viscosity and diffusivity) is quenched by a strong flow shear and a strong magnetic field. For a weak flow shear, we further show that the magnetic shear increases the turbulence intensity while decreasing the turbulent transport. In the presence of a strong flow shear, the effect of the magnetic shear is found to oppose the effect of flow shear (which reduces turbulence due to shear stabilization) by enhancing turbulence and transport, thereby weakening the strong quenching by flow shear stabilization. In the case of a strong magnetic field (compared to flow shear), magnetic shear increases turbulence intensity and quenches turbulent transport.",
author = "Nicolas Leprovost and Kim, {Eun Jin}",
year = "2009",
month = "8",
day = "5",
doi = "10.1103/PhysRevE.80.026302",
language = "English",
volume = "80",
journal = "Physical Review E",
issn = "1539-3755",
publisher = "APS",
number = "2",

}

TY - JOUR

T1 - Turbulent transport and dynamo in sheared magnetohydrodynamics turbulence with a nonuniform magnetic field

AU - Leprovost, Nicolas

AU - Kim, Eun Jin

PY - 2009/8/5

Y1 - 2009/8/5

N2 - We investigate three-dimensional magnetohydrodynamics turbulence in the presence of velocity and magnetic shear (i.e., with both a large-scale shear flow and a nonuniform magnetic field). By assuming a turbulence driven by an external forcing with both helical and nonhelical spectra, we investigate the combined effect of these two shears on turbulence intensity and turbulent transport represented by turbulent diffusivities (turbulent viscosity, α and β effect) in Reynolds-averaged equations. We show that turbulent transport (turbulent viscosity and diffusivity) is quenched by a strong flow shear and a strong magnetic field. For a weak flow shear, we further show that the magnetic shear increases the turbulence intensity while decreasing the turbulent transport. In the presence of a strong flow shear, the effect of the magnetic shear is found to oppose the effect of flow shear (which reduces turbulence due to shear stabilization) by enhancing turbulence and transport, thereby weakening the strong quenching by flow shear stabilization. In the case of a strong magnetic field (compared to flow shear), magnetic shear increases turbulence intensity and quenches turbulent transport.

AB - We investigate three-dimensional magnetohydrodynamics turbulence in the presence of velocity and magnetic shear (i.e., with both a large-scale shear flow and a nonuniform magnetic field). By assuming a turbulence driven by an external forcing with both helical and nonhelical spectra, we investigate the combined effect of these two shears on turbulence intensity and turbulent transport represented by turbulent diffusivities (turbulent viscosity, α and β effect) in Reynolds-averaged equations. We show that turbulent transport (turbulent viscosity and diffusivity) is quenched by a strong flow shear and a strong magnetic field. For a weak flow shear, we further show that the magnetic shear increases the turbulence intensity while decreasing the turbulent transport. In the presence of a strong flow shear, the effect of the magnetic shear is found to oppose the effect of flow shear (which reduces turbulence due to shear stabilization) by enhancing turbulence and transport, thereby weakening the strong quenching by flow shear stabilization. In the case of a strong magnetic field (compared to flow shear), magnetic shear increases turbulence intensity and quenches turbulent transport.

UR - http://www.scopus.com/inward/record.url?scp=68949183496&partnerID=8YFLogxK

U2 - 10.1103/PhysRevE.80.026302

DO - 10.1103/PhysRevE.80.026302

M3 - Article

VL - 80

JO - Physical Review E

JF - Physical Review E

SN - 1539-3755

IS - 2

M1 - 026302

ER -