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

@article{Singh2011TransportCF, title={Transport coefficients for the shear dynamo problem at small Reynolds numbers.}, author={Nishant Kumar Singh and S. Sridhar}, journal={Physical review. E, Statistical, nonlinear, and soft matter physics}, year={2011}, volume={83 5 Pt 2}, pages={ 056309 } }

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, but for arbitrary values of the shear parameter. Specializing to the case of a mean magnetic field that is slowly varying in time, explicit expressions for the transport coefficients α(il) and η(il) are derived. We prove that when the velocity field is nonhelical, the transport coefficient α(il…

## 17 Citations

### The shear dynamo problem for small magnetic Reynolds numbers

- PhysicsJournal of Fluid Mechanics
- 2010

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…

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

- PhysicsMonthly Notices of the Royal Astronomical Society
- 2020

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…

### NUMERICAL STUDIES OF DYNAMO ACTION IN A TURBULENT SHEAR FLOW. I.

- Physics
- 2015

We perform numerical experiments to study the shear dynamo problem where we look for the growth of a large-scale magnetic field due to non-helical stirring at small scales in a background linear…

### Calculating turbulent transport tensors by averaging single-plume dynamics and application to dynamos

- PhysicsMonthly Notices of the Royal Astronomical Society: Letters
- 2018

Transport coefficients in turbulence are comprised of correlation functions between turbulent fluctuations and efficient methods to calculate them are desirable. For example, in mean field dynamo…

### Generation of large-scale magnetic ﬁelds due to ﬂuctuating α in shearing systems

- Physics
- 2018

We explore the growth of large-scale magnetic ﬁelds in a shear ﬂow, due to helicity ﬂuctuations with a ﬁnite correlation time, through a study of the Kraichnan–Moffatt model of zero-mean stochastic…

### Large-scale magnetic field generation by randomly forced shearing waves.

- PhysicsPhysical review letters
- 2011

A minimal proof-of-concept quasilinear calculation aiming to put the shear dynamo, a new effect recently found in numerical experiments, on a firm theoretical footing, suggests that shear dynamic action may be a generic property of sheared magnetohydrodynamic turbulence.

### COHERENT NONHELICAL SHEAR DYNAMOS DRIVEN BY MAGNETIC FLUCTUATIONS AT LOW REYNOLDS NUMBERS

- Physics
- 2015

Nonhelical shear dynamos are studied with a particular focus on the possibility of coherent dynamo action. The primary results—serving as a follow up to the results of Squire & Bhattacharjee—pertain…

### On the shear-current effect: toward understanding why theories and simulations have mutually and separately conflicted

- PhysicsMonthly Notices of the Royal Astronomical Society
- 2021

The shear-current effect (SCE) of mean-field dynamo theory refers to the combination of a shear flow and a turbulent coefficient β21 with a favourable negative sign for exponential mean-field…

### Current Status of Turbulent Dynamo Theory

- Physics
- 2012

Several recent advances in turbulent dynamo theory are reviewed. High resolution simulations of small-scale and large-scale dynamo action in periodic domains are compared with each other and…

### Enhancement of Small-scale Turbulent Dynamo by Large-scale Shear

- Physics
- 2016

Small-scale dynamos (SSDs) are ubiquitous in a broad range of turbulent flows with large-scale shear, ranging from solar and galactic magnetism to accretion disks, cosmology, and structure formation.…

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