scholarly journals Self-similar inverse cascade of magnetic helicity driven by the chiral anomaly

2015 ◽  
Vol 92 (12) ◽  
Author(s):  
Yuji Hirono ◽  
Dmitri E. Kharzeev ◽  
Yi Yin
Keyword(s):  
Magnetic Helicity ◽  
Chiral Anomaly ◽  
Inverse Cascade ◽  
Self Similar

Inverse cascade in simulated MHD turbulence driven by small scale source of magnetic helicity

2016 ◽  
Vol 52 (1) ◽  
pp. 261-268
Author(s):  
R. Stepanov ◽  
◽  
V. Titov ◽  
◽  
Keyword(s):  
Magnetic Helicity ◽  
Small Scale ◽  
Mhd Turbulence ◽  
Inverse Cascade

scholarly journals On the Inverse Cascade of Magnetic Helicity

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

scholarly journals von Kármán self-preservation hypothesis for magnetohydrodynamic turbulence and its consequences for universality

2012 ◽  
Vol 697 ◽  
pp. 296-315 ◽  
Author(s):  
Minping Wan ◽  
Sean Oughton ◽  
Sergio Servidio ◽  
William H. Matthaeus
Keyword(s):  
Evolution Equations ◽  
Similarity Solutions ◽  
Magnetic Helicity ◽  
Mhd Turbulence ◽  
Third Order ◽  
Length Scales ◽  
Decay Behaviour ◽  
Self Similar ◽  
Implicit Dependence ◽  
Kolmogorov Theory

AbstractWe argue that the hypothesis of preservation of shape of dimensionless second- and third-order correlations during decay of incompressible homogeneous magnetohydrodynamic (MHD) turbulence requires, in general, at least two independent similarity length scales. These are associated with the two Elsässer energies. The existence of similarity solutions for the decay of turbulence with varying cross-helicity implies that these length scales cannot remain in proportion, opening the possibility for a wide variety of decay behaviour, in contrast to the simpler classic hydrodynamics case. Although the evolution equations for the second-order correlations lack explicit dependence on either the mean magnetic field or the magnetic helicity, there is inherent implicit dependence on these (and other) quantities through the third-order correlations. The self-similar inertial range, a subclass of the general similarity case, inherits this complexity so that a single universal energy spectral law cannot be anticipated, even though the same pair of third-order laws holds for arbitrary cross-helicity and magnetic helicity. The straightforward notion of universality associated with Kolmogorov theory in hydrodynamics therefore requires careful generalization and reformulation in MHD.

scholarly journals MAGNETIC HELICITY OF SELF-SIMILAR AXISYMMETRIC FORCE-FREE FIELDS

2012 ◽  
Vol 755 (1) ◽  
pp. 78 ◽  
Author(s):  
Mei Zhang ◽  
Natasha Flyer ◽  
Boon Chye Low
Keyword(s):  
Magnetic Helicity ◽  
Self Similar ◽  
Free Fields

scholarly journals Helical mode interactions and spectral transfer processes in magnetohydrodynamic turbulence

2016 ◽  
Vol 791 ◽  
pp. 61-96 ◽  
Author(s):  
Moritz Linkmann ◽  
Arjun Berera ◽  
Mairi McKay ◽  
Julia Jäger
Keyword(s):  
Energy Transfer ◽  
Magnetic Fields ◽  
Magnetic Helicity ◽  
Asymmetric Effect ◽  
Mhd Turbulence ◽  
Dynamo Action ◽  
Reverse Transfer ◽  
Transfer Processes ◽  
Inverse Cascade ◽  
Mode Interactions

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. Steady solutions of the dynamical system which governs the evolution of the helical modes are determined, and a stability analysis of these solutions is carried out. The interpretation of the analysis is that unstable solutions lead to energy transfer between the interacting modes while stable solutions do not. From this, a dependence of possible interscale energy and helicity transfers on the helicities of the interacting modes is derived. As expected from the inverse cascade of magnetic helicity in 3-D MHD turbulence, mode interactions with like helicities lead to transfer of energy and magnetic helicity to smaller wavenumbers. However, some interactions of modes with unlike helicities also contribute to an inverse energy transfer. As such, an inverse energy cascade for non-helical magnetic fields is shown to be possible. Furthermore, it is found that high values of the cross-helicity may have an asymmetric effect on forward and reverse transfer of energy, where forward transfer is more quenched in regions of high cross-helicity than reverse transfer. This conforms with recent observations of solar wind turbulence. For specific helical interactions the relation to dynamo action is established. The present analysis provides new theoretical insights into physical processes where inverse cascade and dynamo action are involved, such as the evolution of cosmological and astrophysical magnetic fields and laboratory plasmas.

scholarly journals Self-similar formation of an inverse cascade in vibrating elastic plates

2015 ◽  
Vol 91 (5) ◽  
Author(s):  
Gustavo Düring ◽  
Christophe Josserand ◽  
Sergio Rica
Keyword(s):  
Elastic Plates ◽  
Inverse Cascade ◽  
Self Similar ◽  
Similar Formation

scholarly journals Inverse cascade of magnetic helicity in magnetohydrodynamic turbulence

2012 ◽  
Vol 85 (1) ◽  
Author(s):  
Wolf-Christian Müller ◽  
Shiva Kumar Malapaka ◽  
Angela Busse
Keyword(s):  
Magnetic Helicity ◽  
Magnetohydrodynamic Turbulence ◽  
Inverse Cascade

scholarly journals The Solar Dynamo: Old, Recent, and New Problems

2001 ◽  
Vol 203 ◽  
pp. 144-151
Author(s):  
A. Brandenburg
Keyword(s):  
Numerical Simulations ◽  
Mean Field ◽  
Direct Numerical Simulations ◽  
Solar Dynamo ◽  
Magnetic Helicity ◽  
Current Status ◽  
Dynamo Theory ◽  
Inverse Cascade ◽  
Mean Field Dynamo ◽  
Stellar Dynamo

A number of problems of solar and stellar dynamo theory are briefly reviewed and the current status of possible solutions is discussed. Results of direct numerical simulations are described in view of mean-field dynamo theory and the relation between the α-effect and the inverse cascade of magnetic helicity is highlighted. The possibility of ‘catastrophic’ quenching of the α-effect is explained in terms of the constraint placed by the conservation of magnetic helicity.

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