Dynamo instabilities in plasmas with inhomogeneous chiral chemical potential

Abstract

We study the dynamics of magnetic fields in chiral magnetohydrodynamics, which takes into account the effects of an additional electric current related to the chiral magnetic effect in high energy plasmas. We perform direct numerical simulations, considering weak seed magnetic fields and inhomogeneities of the chiral chemical potential mu_5 with a zero mean. We demonstrate that a small-scale chiral dynamo can occur in such plasmas if fluctuations of mu_5 are correlated on length scales that are much larger than the scale on which the dynamo growth rate reaches its maximum. Magnetic fluctuations grow by many orders of magnitude due to the small-scale chiral dynamo instability. Once the nonlinear backreaction of the generated magnetic field on fluctuations of mu_5 sets in, the ratio of these scales decreases and the dynamo saturates. When magnetic fluctuations grow sufficiently to drive turbulence via the Lorentz force before reaching maximum field strength, an additional mean-field dynamo phase is identified. The mean magnetic field grows on a scale that is larger than the integral scale of turbulence after the amplification of the fluctuating component saturates. The growth rate of the mean magnetic field is caused by a magnetic alpha effect that is proportional to the current helicity. With the onset of turbulence, the power spectrum of mu_5 develops a universal k^(-1) scaling independently of its initial shape, while the magnetic energy spectrum approaches a k^(-3) scaling.

arXiv comment22 pages, 22 figures

References in corpus (41)

• The effects of topological charge change in heavy ion collisions: "Event by event P and CP violation"
• Astrophysical magnetic fields and nonlinear dynamo theory
• Chiral Magnetic and Vortical Effects in High-Energy Nuclear Collisions --- A Status Report
• Azimuthal Charged-Particle Correlations and Possible Local Strong Parity Violation
• The Chiral Magnetic Effect and Anomaly-Induced Transport
• Primordial Magnetic Fields, Right Electrons, and the Abelian Anomaly
• Chiral Magnetic Wave
• Charge separation relative to the reaction plane in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV
• Hydromagnetic turbulence in computer simulations
• Self-consistent evolution of magnetic fields and chiral asymmetry in the early Universe
• The Pencil Code, a modular MPI code for partial differential equations and particles: multipurpose and multiuser-maintained
• On the Baryon, Lepton-Flavour and Right-Handed Electron Asymmetries of the Universe
• Primordial Magnetic Fields
• Large-scale dynamos in turbulent convection with shear
• Chiral transport of neutrinos in supernovae: Neutrino-induced fluid helicity and helical plasma instability
• Self-similar inverse cascade of magnetic helicity driven by the chiral anomaly
• Magnetic Helicity Tensor for an Anisotropic Turbulence
• Computational aspects of astrophysical MHD and turbulence
• Advances in mean-field dynamo theory and applications to astrophysical turbulence
• Laminar and turbulent dynamos in chiral magnetohydrodynamics-I: Theory
• The turbulent chiral-magnetic cascade in the early universe
• Topological Currents in Neutron Stars: Kicks, Precession, Toroidal Fields, and Magnetic Helicity
• Magnetic Field Amplification in Young Galaxies
• Chiral Magnetic Effect in Protoneutron Stars and Magnetic Field Spectral Evolution
• Laminar and turbulent dynamos in chiral magnetohydrodynamics. II. Simulations
• MagnetoHydrodynamics with chiral anomaly: phases of collective excitations and instabilities
• Influence of the turbulent motion on the chiral magnetic effect in the early Universe
• Covariant and 3+1 Equations for Dynamo-Chiral General Relativistic Magnetohydrodynamics
• Anomalous Magnetohydrodynamics
• Relic gravitational waves from the chiral magnetic effect
• Anomaly-driven inverse cascade and inhomogeneities in a magnetized chiral plasma in the early Universe
• Dynamo Effect and Turbulence in Hydrodynamic Weyl Metals
• Evolution of the Primordial Axial Charge across Cosmic Times
• Chiral fermion asymmetry in high-energy plasma simulations
• Production of a chiral magnetic anomaly with emerging turbulence and mean-field dynamo action
• Generation of chiral asymmetry via helical magnetic fields
• Magnetars and the Chiral Plasma Instabilities
• Energetics of turbulence generated by chiral MHD dynamos
• Non-linear Galactic Dynamos and the Magnetic Rädler Effect
• Generation of strong magnetic fields in a nascent neutron star accounting for the chiral magnetic effect
• Convergence properties of detonation simulations

Cited by in corpus (8)

• Chiral effects in astrophysics and cosmology
• Production of a chiral magnetic anomaly with emerging turbulence and mean-field dynamo action
• Chiral magnetohydrodynamics with zero total chirality
• Dwarf galaxies as a probe of a primordially magnetized Universe
• Chiral anomaly and dynamos from inhomogeneous chemical potential fluctuations
• Analytic solutions for the linearized first-order magnetohydrodynamics and implications for causality and stability
• Primordial magnetic field from chiral plasma instability with sourcing
• Efficiency of dynamos from an autonomous generation of chiral asymmetry