scholarly journals Inverse cascade of magnetic helicity in magnetohydrodynamic turbulence

2012 ◽  
Vol 85 (1) ◽  
Author(s):  
Wolf-Christian Müller ◽  
Shiva Kumar Malapaka ◽  
Angela Busse
2016 ◽  
Vol 52 (1) ◽  
pp. 261-268
Author(s):  
R. Stepanov ◽  
◽  
V. Titov ◽  
◽  

2008 ◽  
Vol 78 (12) ◽  
Author(s):  
Tina Kahniashvili ◽  
Leonardo Campanelli ◽  
Grigol Gogoberidze ◽  
Yurii Maravin ◽  
Bharat Ratra

2006 ◽  
Vol 640 (1) ◽  
pp. 335-343 ◽  
Author(s):  
Alexandros Alexakis ◽  
Pablo D. Mininni ◽  
Annick Pouquet

2020 ◽  
Author(s):  
Timofey Zinyakov ◽  
Arakel Petrosyan

<p>Numerical studies of two-dimensional β-plane homogeneous magnetohydrodynamic turbulence are presented. The study of the fundamental properties of such turbulence allows understanding the evolution of various astrophysical objects from the Sun and stars to planetary systems, galaxies, and galaxy clusters. Energy spectra and cascade process in two-dimensional β-plane MHD are studied.</p><p>In this work the equations of two-dimensional magnetohydrodynamics with the Coriolis force in the β-plane approximation are used for the qualitative analysis and numerical simulation of processes in plasma astrophysics. The equations are solved on a square box of edge size 2π with periodic boundary conditions applying a the pseudospectral method using the 2/3 rule for dealiasing. The results of numerical simulation of two-dimensional β-plane MHD turbulence with a spatial resolution of 1024 × 1024 and 4096 × 4096 with different Rossby parameters β and different Reynolds numbers are presented.</p><p>It is found that only unsteady zonal flows with complex temporal dynamics are formed in two-dimensional β-plane magnetohydrodynamic turbulence. It is shown that flow nonstationarity is due to the appearance of isotropic magnetic islands caused by the Lorentz force in the system. The formation of Iroshnikov–Kraichnan spectrum is shown in the early stages of evolution of two-dimensional β-plane magnetohydrodynamic turbulence. The self-similarity of the decay of Iroshnikov–Kraichnan spectrum is studied. On long time scale violation of self-similarity of the decay and formation of Kolmogorov spectrum is discovered. The inverse cascade of kinetic energy, which is characteristic of the detected Kolmogorov spectrum, provides the formation of zonal flows.</p><p>This work was supported by the Russian Foundation for Basic Research (project no. 19-02-00016).</p>


1975 ◽  
Vol 68 (4) ◽  
pp. 769-778 ◽  
Author(s):  
U. Frisch ◽  
A. Pouquet ◽  
J. LÉOrat ◽  
A. Mazure

Some of the consequences of the conservation of magnetic helicity$\int \rm{a.b}\it{d}^{\rm{3}}\rm{r\qquad (a\; =\; vector\; potential\; of\; magnetic\; field\; b)}$for incompressible three-dimensional turbulent MHD flows are investigated. Absolute equilibrium spectra for inviscid infinitely conducting flows truncated at lower and upper wavenumberskminandkmaxare obtained. When the total magnetic helicity approaches an upper limit given by the total energy (kinetic plus magnetic) divided bykmin, the spectra of magnetic energy and helicity are strongly peaked nearkmin; in addition, when the cross-correlations between the velocity and magnetic fields are small, the magnetic energy density nearkmingreatly exceeds the kinetic energy density. Several arguments are presented in favour of the existence of inverse cascades of magnetic helicity towards small wavenumbers leading to the generation of large-scale magnetic energy.


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