# Purely helical absolute equilibria and chirality of (magneto)fluid turbulence

@article{Zhu2014PurelyHA, title={Purely helical absolute equilibria and chirality of (magneto)fluid turbulence}, author={Jian-Zhou Zhu and Wei-hong Yang and Guang-Yu Zhu}, journal={Journal of Fluid Mechanics}, year={2014}, volume={739}, pages={479 - 501} }

Abstract Purely helical absolute equilibria of incompressible neutral fluids and plasmas (electron, single-fluid and two-fluid magnetohydrodynamics) are systematically studied with the help of helical (wave) representation and truncation, for genericities and specificities about helicity. A unique chirality selection and amplification mechanism and relevant insights, such as the one-chiral-sector-dominated states, among others, about (magneto)fluid turbulence follow.

## 29 Citations

Helical Fluid and (Hall)-MHD Turbulence: a Brief Review

- Physics
- 2021

Helicity, a measure of the breakage of reflectional symmetry representing the topology of turbulent flows, contributes in a crucial way to their dynamics and to their fundamental statistical…

On the exact solutions of (magneto)hydrodynamic systems and the superposition principles of nonlinear helical waves

- Physics
- 2014

The principles of restricted superposition of circularly polarized arbitrary-amplitude waves for several hydrodynamic type models are illustrated systematically with helical representation in a…

Isotropic polarization of compressible flows

- PhysicsJournal of Fluid Mechanics
- 2015

The helical absolute equilibrium of a compressible adiabatic flow presents not only polarization between two purely helical modes of opposite chiralities but also that between vortical and acoustic…

Helical mode interactions and spectral transfer processes in magnetohydrodynamic turbulence

- PhysicsJournal of Fluid Mechanics
- 2016

Spectral transfer processes in homogeneous magnetohydrodynamic (MHD) turbulence are investigated analytically by decomposition of the velocity and magnetic fields in Fourier space into helical modes.…

Self-organisation processes in (magneto)hydrodynamic turbulence

- Physics
- 2016

Self-organising processes occurring in isotropic turbulence and homogeneous magnetohydrodynamic (MHD) turbulence are investigated in relation to the stability of helical flow structures. A stability…

Helicity Dynamics, Inverse, and Bidirectional Cascades in Fluid and Magnetohydrodynamic Turbulence: A Brief Review

- PhysicsEarth and Space Science
- 2019

We briefly review helicity dynamics, inverse and bidirectional cascades in fluid and magnetohydrodynamic (MHD) turbulence, with an emphasis on the latter. The energy of a turbulent system, an…

Direction of cascades in a magnetofluid model with electron skin depth and ion sound Larmor radius scales

- PhysicsPhysics of Plasmas
- 2018

The direction of cascades in a two-dimensional model that takes electron inertia and ion sound Larmor radius into account is studied, resulting in analytical expressions for the absolute equilibrium…

Note on specific chiral ensembles of statistical hydrodynamics: “Order function” for transition of turbulence transfer scenarios

- Physics
- 2014

Hydrodynamic helicity signatures the parity symmetry breaking, chirality, of the flow. Statistical hydrodynamics thus respect chirality, as symmetry breaking and restoration are key to its…

Coupling Large Eddies and Waves in Turbulence: Case Study of Magnetic Helicity at the Ion Inertial Scale

- Physics
- 2020

In turbulence, for neutral or conducting fluids, a large ratio of scales is excited because of the possible occurrence of inverse cascades to large, global scales together with direct cascades to…

## References

SHOWING 1-10 OF 95 REFERENCES

Helical and Nonhelical Turbulent Dynamos

- Physics
- 1981

Direct numerical simulations of three-dimensional magnetohydrodynamic turbulence with kinetic and magnetic Reynolds numbers up to 100 are presented. Spatially intermittent magnetic fields are…

Spontaneous chiral symmetry breaking of Hall magnetohydrodynamic turbulence.

- Physics, MedicinePhysical review letters
- 2012

It is shown that the Hall effect induces a spontaneous chiral symmetry breaking of the turbulent dynamics of solar wind turbulence, and the normalized magnetic polarization is introduced to separate the right- and left-handed fluctuations.

Dissipation in helical turbulence

- Physics
- 2001

In helical turbulence a linear cascade of helicity accompanying the energy cascade has been suggested. Since energy and helicity have different dimensionality we suggest the existence of a…

A weak turbulence theory for incompressible magnetohydrodynamics

- PhysicsJournal of Plasma Physics
- 2000

We derive a weak turbulence formalism for incompressible magnetohydrodynamics. Three-wave interactions lead to a system of kinetic equations for the spectral densities of energy and helicity. The…

Turbulent Dynamos and Magnetic Helicity

- Physics
- 1999

It is shown that the turbulent dynamo alpha-effect converts magnetic helicity from the turbulent field to the mean field when the turbulence is electromagnetic while the magnetic helicity of the…

Equilibrium analysis of a flowing two-fluid plasma

- Physics
- 2002

An improved formalism for a flowing two-fluid equilibrium with constant density is developed. This extends the usual single-fluid model. In this generalization, the magnetic field is replaced by two…

Strong MHD helical turbulence and the nonlinear dynamo effect

- Physics
- 1976

To understand the turbulent generation of large-scale magnetic fields and to advance beyond purely kinematic approaches to the dynamo effect like that introduced by Steenbeck, Krause & Radler (1966)’…

Two-dimensional turbulence

- Physics
- 2002

The theory of turbulence in two dimensions is reviewed and unified and a number of hydrodynamic and plasma applications are surveyed. The topics treated include the basic dynamical equations,…

Motion of magnetic flux lines in magnetohydrodynamics

- Physics
- 1999

A gauge-free description of magnetohydrodynamic flows of an ideal incompressible fluid, which takes into account the freezing-in of the magnetic field and the presence of cross invariants containing…

Turbulent Dynamos and Magnetic Helicity

- Physics
- 1999

It is shown that the turbulent dynamo -e ect converts magnetic helicity from the turbulent eld to the mean eld when the turbulence is electromagnetic while the magnetic helicity of the meaneld is…