Parameter study of decaying magnetohydrodynamic turbulence

Abstract

It is well known that helical magnetohydrodynamic (MHD) turbulence exhibits an inverse transfer of magnetic energy from small to large scales, which is related to the approximate conservation of magnetic helicity. Recently, several numerical investigations noticed the existence of an inverse energy transfer also in nonhelical MHD flows. We run a set of fully resolved direct numerical simulations and perform a wide parameter study of the inverse energy transfer and the decaying laws of helical and nonhelical MHD. Our numerical results show only a small inverse transfer of energy that grows as with increasing Prandtl number (Pm). This latter feature may have interesting consequences for cosmic magnetic field evolution. Additionally, we find that the decaying laws $E\sim t^{-p}$ are independent of the scale separation and depend solely on Pm and Re. In the helical case we measure a dependence of the form $p_b\approx 0.6+14/Re$. We also make a comparison between our results and previous literature and discuss the possible reason for the observed disagreements

19 pages, 20 figures

References in corpus (20)

• MHD simulations of the magnetorotational instability in a shearing box with zero net flux. II. The effect of transport coefficients
• Nonhelical inverse transfer of a decaying turbulent magnetic field
• Shell Models of Magnetohydrodynamic Turbulence
• Classes of hydrodynamic and magnetohydrodynamic turbulent decay
• The Turbulent Dynamo in Highly Compressible Supersonic Plasmas
• On the Relaxation of Turbulence at High Reynolds Numbers
• Inverse cascade of non-helical magnetic turbulence in a relativistic fluid
• Evolution of Magnetic Fields in Freely Decaying Magnetohydrodynamic Turbulence
• Magnetic Fields from QCD Phase Transitions
• MHD Turbulence
• Laws of turbulence decay from direct numerical simulations
• Evolution of primordial magnetic fields during large-scale structure formation
• Reconnection-controlled decay of magnetohydrodynamic turbulence and the role of invariants
• Nonhelical turbulence and the inverse transfer of energy: A parameter study
• Scaling of the Hosking integral in decaying magnetically-dominated turbulence
• Inverse energy transfer in decaying, three dimensional, nonhelical magnetic turbulence due to magnetic reconnection
• Magnetic helicity and the evolution of decaying magnetohydrodynamic turbulence
• Statistical description of coalescing magnetic islands via magnetic reconnection
• Joint inverse cascade of magnetic energy and magnetic helicity in MHD turbulence
• On the Inverse Transfer of (Non-)Helical Magnetic Energy in a Decaying Magnetohydrodynamic Turbulence

Cited by in corpus (5)

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• Inverse cascading for initial MHD turbulence spectra between Saffman and Batchelor
• Primordial black holes and magnetic fields in conformal neutrino mass models
• Inverse cascade from helical and nonhelical decaying columnar magnetic fields