Nonhelical turbulence and the inverse transfer of energy: A parameter study

Abstract

We explore the phenomenon of the recently discovered inverse transfer of energy from small to large scales in decaying magnetohydrodynamical turbulence by Brandenburg et al. (2015) even for nonhelical magnetic fields. For this investigation we mainly employ the Pencil-Code performing a parameter study, where we vary the Prandtl number, the kinematic viscosity and the initial spectrum. We find that in order to get a decay which exhibits this inverse transfer, large Reynolds numbers ($\mathcal{O}\sim 10^3$) are needed and low Prandtl numbers of the order unity $Pr=1$ are preferred. Compared to helical MHD turbulence, though, the inverse transfer is much less efficient in transferring magnetic energy to larger scales than the well-known effect of the inverse cascade. Hence, applying the inverse transfer to the magnetic field evolution in the Early Universe, we question whether the nonhelical inverse transfer is effective enough to explain the observed void magnetic fields if a magneto- genesis scenario during the electroweak phase transition is assumed.

13 Pages, accepted to Physical Review E

References in corpus (9)

• Simulations of nonhelical hydromagnetic turbulence
• A new Jeans resolution criterion for (M)HD simulations of self-gravitating gas: Application to magnetic field amplification by gravity-driven turbulence
• Nonhelical inverse transfer of a decaying turbulent magnetic field
• Evolution of Primordial Magnetic Fields from Phase Transitions
• Inertial range scaling in numerical turbulence with hyperviscosity
• Inverse cascade of non-helical magnetic turbulence in a relativistic fluid
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• On the parallel spectrum in MHD Turbulence
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Cited by in corpus (12)

• Evolution of hydromagnetic turbulence from the electroweak phase transition
• Generation of gravitational waves from freely decaying turbulence
• Scaling of the Hosking integral in decaying magnetically-dominated turbulence
• Turbulence with Magnetic Helicity that is Absent on Average
• Batchelor, Saffman, and Kazantsev spectra in galactic small-scale dynamos
• Can the Local Bubble explain the radio background?
• Magnetic helicity dissipation and production in an ideal MHD code
• Parameter study of decaying magnetohydrodynamic turbulence
• Inverse cascading for initial MHD turbulence spectra between Saffman and Batchelor
• New description of the scaling evolution of the cosmological magneto-hydrodynamic system
• Anisotropic gravitational waves induced by hypermagnetic fields during the electroweak phase transition epoch
• Revisiting constraints on primordial magnetic fields from spectral distortions of cosmic microwave background