Mean field dynamo action in shear flows. I: fixed kinetic helicity

  title={Mean field dynamo action in shear flows. I: fixed kinetic helicity},
  author={Naveen Jingade and Nishant Kumar Singh},
  journal={Monthly Notices of the Royal Astronomical Society},
We study mean field dynamo action in a background linear shear flow by employing pulsed renewing flows with fixed kinetic helicity and non-zero correlation time (τ). We use plane shearing waves in terms of time-dependent exact solutions to the Navier–Stokes equation as derived by Singh & Sridhar (2017). This allows us to self-consistently include the anisotropic effects of shear on the stochastic flow. We determine the average response tensor governing the evolution of mean magnetic field… 
2 Citations

Figures from this paper

Mean-Field Dynamo Model in Anisotropic Uniform Turbulent Flow with Short-Time Correlations

The mean-field model is one of the basic models of the dynamo theory, which describes the magnetic field generation in a turbulent astrophysical plasma. The first mean-field equations were obtained

The pressure characteristics analysis of oil pulsation flow based on VMD

The results show that the proposed center frequency slope criterion method is effective in the VMD decomposition of the pressure signal of oil pulsating flow, which is used to decompose thepressure signal into 9 components.



Mean-field dynamo action in renovating shearing flows.

We study mean-field dynamo action in renovating flows with finite and nonzero correlation time (τ) in the presence of shear. Previous results obtained when shear was absent are generalized to the

The shear dynamo problem for small magnetic Reynolds numbers

We study large-scale kinematic dynamo action due to turbulence in the presence of a linear shear flow in the low-conductivity limit. Our treatment is non-perturbative in the shear strength and makes

Transport coefficients for the shear dynamo problem at small Reynolds numbers.

  • N. SinghS. Sridhar
  • Physics
    Physical review. E, Statistical, nonlinear, and soft matter physics
  • 2011
We build on the formulation developed in S. Sridhar and N. K. Singh [J. Fluid Mech. 664, 265 (2010)] and present a theory of the shear dynamo problem for small magnetic and fluid Reynolds numbers,

Nonperturbative quasilinear approach to the shear dynamo problem.

To all orders in the shear parameter, there is no shear-current-type effect for non helical turbulence in a linear shear flow in quasilinear theory in the limit of zero resistivity.

The helicity constraint in turbulent dynamos with shear

ABSTRA C T The evolution of magnetic fields is studied using simulations of forced helical turbulence with strong imposed shear. After some initial exponential growth, the magnetic field develops a

Alpha effect and diffusivity in helical turbulence with shear

Aims. We study the dependence of turbulent transport coefficients, such as the components of the α tensor (αij) and the turbulent magnetic diffusivity tensor (ηij), on shear and magnetic Reynolds

Magnetic Diffusivity Tensor and Dynamo Effects in Rotating and Shearing Turbulence

The turbulent magnetic diffusivity tensor is determined in the presence of rotation or shear. The question is addressed whether dynamo action from the shear-current effect can explain large-scale

Dynamo quenching due to shear flow.

It is shown that the alpha effect is reduced by the shear even in the absence of magnetic field, suggesting a crucial effect of shear and magnetic field on dynamo quenching and momentum transport reduction, with important implications for laboratory and astrophysical plasmas.

The supernova-regulated ISM. III. Generation of vorticity, helicity and mean flows

The forcing of interstellar turbulence, driven mainly by supernova explosions, is irrotational in nature, but the development of significant amounts of vorticity and helicity, accompanied by

Non-local memory effects of the electromotive force by fluid motion with helicity and two-dimensional periodicity

In mean-field dynamo theory, the electromotive force term ⟨u′ × B′⟩ due to small-scale fields connects the small-scale magnetic field with the large-scale field. This term is usually approximated as