Mechanism for sequestering magnetic energy at large scales in shear-flow turbulence

  title={Mechanism for sequestering magnetic energy at large scales in shear-flow turbulence},
  author={Bindesh Tripathi and Adrian E. Fraser and Paul W. Terry and Ellen G. Zweibel and M. J. Pueschel},
  journal={Physics of Plasmas},
Straining of magnetic fields by large-scale shear flow, which is generally assumed to lead to intensification and generation of small scales, is reexamined in light of the persistent observation of large-scale magnetic fields in astrophysics. It is shown that, in magnetohydrodynamic turbulence, unstable shear flows have the unexpected effect of sequestering magnetic energy at large scales due to counteracting straining motion of nonlinearly excited large-scale stable eigenmodes. This effect is… 

Figures from this paper


Dedalus: A flexible framework for numerical simulations with spectral methods
The numerical method is a first-order generalized tau formulation that discretizes equations into banded matrices that is implemented with an object-oriented design and the design and implementation of the Dedalus codebase is described.
The impact of magnetic fields on momentum transport and saturation of shear-flow instability by stable modes
The Kelvin-Helmholtz (KH) instability of a shear layer with an initially-uniform magnetic field in the direction of flow is studied in the framework of 2D incompressible magnetohydrodynamics with
Near-cancellation of up- and down-gradient momentum transport in forced magnetized shear-flow turbulence
Near-cancellation of upand down-gradient momentum transport in forced magnetized shear-flow turbulence B. Tripathi, A.E. Fraser, P.W. Terry, E.G. Zweibel, and M.J. Pueschel University of
Turbulent shear layers in a uniformly stratified background: DNS at high Reynolds number
Abstract Direct numerical simulations are performed to investigate a stratified shear layer at high Reynolds number ($Re$) in a study where the Richardson number ($Ri$) is varied among cases. Unlike
Turbulence in forced stratified shear flows
Abstract Continuously forced, stratified shear flows occur in many geophysical systems, including flow over sills, through fjords and at the mouths of rivers and estuaries. These continuously forced
The physics of spontaneous parity-time symmetry breaking in the Kelvin–Helmholtz instability
We show that the dynamical system of an inviscid fluid with velocity shear admits parity-time (PT) symmetry, which provides a physical explanation of the well-known observation that the spectrum of
Energy Transfer from Large to Small Scales in Turbulence by Multiscale Nonlinear Strain and Vorticity Interactions.
In this Letter, an exact relationship is derived which quantitatively establishes how intuitive multiscale mechanisms such as vorticity stretching and strain self-amplification together actuate the interscale transfer of energy in turbulence.
PT symmetry in quantum and classical physics
The field of PT (parity-time) symmetry was originated by Carl M. Bender in 1998 with a paper in which he demonstrated that Hamiltonians that are PT-symmetric but not Hermitian can describe actual p...
The Structure of Turbulent Shear Flow
Note: Bibliogr. : p. 413-424. Index Reference Record created on 2004-09-07, modified on 2016-08-08
Multi-scale interactions between turbulence and magnetic islands and parity mixture—a review
This paper presents a review of multi-scale interactions between small-scale turbulence and large scale magnetic islands. In finite beta plasmas, zonal flows are relatively weak, and thus another