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The existence of partially conserved enstrophy-like quantities is conjectured to cause inverse energy transfers to develop embedded in magnetohydrodynamical (MHD) turbulence, in analogy to the influence of enstrophy in two-dimensional…

Fluid Dynamics · Physics 2020-01-08 Nicholas Rathmann , Peter Ditlevsen

We study the inverse cascade of magnetic helicity in conducting fluids by investigating the detailed transfer of helicity between different spherical shells in Fourier space in direct numerical simulations of three-dimensional…

Plasma Physics · Physics 2009-11-11 Alexandros Alexakis , Pablo Mininni , Annick Pouquet

The shell-to-shell energy transfer rates for magnetohydrodynamic (MHD) turbulence are computed analytically, which shows local energy transfer rates from velocity to velocity, velocity to magnetic, magnetic to velocity, and magnetic to…

Chaotic Dynamics · Physics 2020-06-16 Mahendra K. Verma , Arvind Ayyer , Amar V. Chandra

We investigate the critical transition from an inverse cascade of energy to a forward energy cascade in a two-dimensional magneto-hydrodynamic flow as the ratio of magnetic to mechanical forcing amplitude is varied. It is found that the…

Fluid Dynamics · Physics 2015-09-09 Kannabiran Seshasayanan , Alexandros Alexakis

We perform direct numerical simulations of three-dimensional freely decaying magnetohydrodynamic (MHD) turbulence. For helical magnetic fields an inverse cascade effect is observed in which power is transfered from smaller scales to larger…

Astrophysics · Physics 2009-10-31 Mattias Christensson , Mark Hindmarsh , Axel Brandenburg

The basic entity of nonlinear interaction in Navier-Stokes and the Magnetohydrodynamic (MHD) equations is a wavenumber triad ({\bf k,p,q}) satisfying ${\bf k+p+q=0}$. The expression for the combined energy transfer from two of these…

Chaotic Dynamics · Physics 2009-11-07 Gaurav Dar , Mahendra K. Verma , V. Eswaran

Magnetohydrodynamic turbulence affects both terrestrial and astrophysical plasmas. The properties of magnetized turbulence must be better understood to more accurately characterize these systems. This work presents ideal MHD simulations of…

Fluid Dynamics · Physics 2021-04-28 Forrest W. Glines , Philipp Grete , Brian W. O'Shea

The existence of a total energy cascade and the scale-locality of the total energy flux are rigorously established working directly from the 3D MHD equations and under assumptions consistent with physical properties of turbulent plasmas.…

Mathematical Physics · Physics 2015-06-12 Z. Bradshaw , Z. Grujić

We formulate a coarse-graining approach to the dynamics of magnetohydrodynamic (MHD) fluids at a continuum of length-scales. In this methodology, effective equations are derived for the observable velocity and magnetic fields…

Solar and Stellar Astrophysics · Physics 2017-04-05 Hussein Aluie

Renormalized viscosity, renormalized resistivity, and various energy fluxes are calculated for helical magnetohydrodynamics using perturbative field theory. The calculation is to first-order in perturbation. Kinetic and magnetic helicities…

Chaotic Dynamics · Physics 2008-11-26 Mahendra K. Verma

We have carried out numerical simulations of freely decaying magnetohydrodynamic (MHD) turbulence in three dimensions, which can be applied to the evolution of stochastic magnetic fields in the early Universe. For helical magnetic fields an…

Astrophysics · Physics 2007-05-23 Mark Hindmarsh , M. Christensson , A. Brandenburg

We investigate the locality or nonlocality of the energy transfer and of the spectral interactions involved in the cascade for decaying magnetohydrodynamic (MHD) flows in the presence of a uniform magnetic field $\bf B$ at various…

Fluid Dynamics · Physics 2009-11-13 A. Alexakis , B. Bigot , H. Politano

In magnetohydrodynamic (MHD) turbulence, the large-scale magnetic field sets a preferred local direction for the small-scale dynamics, altering the statistics of turbulence from the isotropic case. This happens even in the absence of a…

Plasma Physics · Physics 2017-05-10 Vladimir Zhdankin , Stanislav Boldyrev , Joanne Mason

We study the properties of sub-Alfvenic magnetohydrodynamic (MHD) turbulence, i.e., turbulence with Alfven Mach number $M_A=V_L/V_A<1$, where $V_L$ is the velocity at the injection scale and $V_A$ is the Alfven velocity. We demonstrate that…

Astrophysics of Galaxies · Physics 2024-10-28 Alex Lazarian , Ka Wai HO , Ka Ho Yuen , Ethan Vishniac

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

Fluid Dynamics · Physics 2016-02-18 Moritz F. Linkmann , Arjun Berera , Mairi E. McKay , Julia Jäger

In our conventional understanding, large-scale magnetic fields are thought to originate from an inverse cascade in the presence of magnetic helicity, differential rotation, or a magneto-rotational instability. However, as recent simulations…

Plasma Physics · Physics 2017-09-20 Kiwan Park

A systematic procedure to derive shell models for MHD turbulence is proposed. It takes into account the conservation of ideal quadratic invariants such as the total energy, the cross-helicity and the magnetic helicity as well as the…

Chaotic Dynamics · Physics 2015-05-13 T. Lessinnes , M. K. Verma , D. Carati

Two-dimensional magnetohydrodynamics (2D MHD), forced at (a) large length scales or (b) small length scales, displays turbulent, but statistically steady, states with widely different statistical properties. We present a systematic,…

Fluid Dynamics · Physics 2019-06-27 Debarghya Banerjee , Rahul Pandit

We present a method to characterize the spectral transfers of magnetic energy between scales in simulations of stellar convective dynamos. The full triadic transfer functions are computed thanks to analytical coupling relations of spherical…

Solar and Stellar Astrophysics · Physics 2013-11-18 A. Strugarek , A. S. Brun , S. Mathis , Y. Sarazin

Electron magnetohydrodynamic (EMHD) turbulence in two dimensions is studied via high-resolution numerical simulations with a normal diffusivity. The resulting energy spectra asymptotically approach a $k^{-5/2}$ law with increasing $R_B$,…

Plasma Physics · Physics 2009-05-01 C. J. Wareing , R. Hollerbach