On Self-Sustained Dynamo Cycles in Accretion Discs

Abstract

(abridged) MHD turbulence is known to exist in shearing boxes with either zero or nonzero net magnetic flux. However, the way turbulence survives in the zero-net-flux case is not explained by linear theory and appears as a purely numerical result. Aims: We look for a nonlinear mechanism able to explain the persistence of MHD turbulence in shearing boxes with zero net magnetic flux, and potentially leading to large-scale dynamo action. Method: Spectral nonlinear simulations of the magnetorotational instability are shown to exhibit a large-scale axisymmetric magnetic field, maintained for a few orbits. The generation process of this field is investigated using the results of the simulations and an inhomogeneous linear approach. Results: The mechanism by which turbulence is sustained in zero-net-flux shearing boxes is shown to be related to the existence of a large-scale azimuthal field, surviving for several orbits. In particular, it is shown that MHD turbulence in shearing boxes can be seen as a dynamo process coupled to a magnetorotational-type instability.

11 pages, 11 figures, Accepted in A&A

References in corpus (17)

• Enhanced Angular Momentum Transport in Accretion Disks
• Global Magnetohydrodynamical Simulations of Accretion Tori
• MHD simulations of the magnetorotational instability in a shearing box with zero net flux. II. The effect of transport coefficients
• Impact of dimensionless numbers on the efficiency of MRI-induced turbulent transport
• The Effect of Resistivity on the Nonlinear Stage of the Magnetorotational Instability in Accretion Disks
• MHD simulations of the magnetorotational instability in a shearing box with zero net flux. I. The issue of convergence
• Electromotive Force and Large-Scale Magnetic Dynamo in a Turbulent Flow with a Mean Shear
• Angular Momentum Transport in Accretion Disks: Scaling Laws in MRI-driven Turbulence
• On the relevance of subcritical hydrodynamic turbulence to accretion disk transport
• Generation of Magnetic Field by Combined Action of Turbulence and Shear
• Hydrodynamic stability of rotationally supported flows: Linear and nonlinear 2D shearing box results
• On the Magnetic Prandtl Number Behavior of Accretion Disks
• A self-sustaining nonlinear dynamo process in Keplerian shear flows
• On the viability of the shearing box approximation for numerical studies of MHD turbulence in accretion disks
• The fundamental difference between shear alpha viscosity and turbulent magnetorotational stresses
• Exact shering box solutions of MHD flows with resistivity, viscosity and cooling
• Toward Coupling Flow Driven and Magnetically Driven Dynamos

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• Periodic magnetorotational dynamo action as a prototype of nonlinear magnetic field generation in shear flows
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• Large Scale Azimuthal Structures Of Turbulence In Accretion Disks - Dynamo triggered variability of accretion
• Generation of large-scale magnetic fields by small-scale dynamo in shear flows
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• MRI-driven $\alpha -\Omega$ dynamos in protoneutron stars
• A mean-field approach to the propagation of field patterns in stratified magneto rotational turbulence
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• The influence of accretion disk thickness on the large-scale magnetic dynamo
• Axisymmetric Magnetorotational Instability in Viscous Accretion Disks
• Global simulations of magnetorotational turbulence I: convergence and the quasi-steady state
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• Local simulations of MRI turbulence with meshless methods
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• The magnetic shear-current effect: generation of large-scale magnetic fields by the small-scale dynamo
• MRI turbulence in accretion discs at large magnetic Prandtl numbers
• Accretion Disks and Dynamos: Toward a Unified Mean Field Theory
• Zero net flux MRI-turbulence in disks $-$ sustenance scheme and magnetic Prandtl number dependence
• Coherent nonhelical shear dynamos driven by magnetic fluctuations at low Reynolds numbers
• Magnetorotational instability with smoothed particle hydrodynamics
• Nonlinear transverse cascade and sustenance of MRI-turbulence in Keplerian disks with an azimuthal magnetic field
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• Active modes and dynamical balances in MRI-turbulence of Keplerian disks with a net vertical magnetic field
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• On the existence of shear-current effects in magnetized burgulence
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• Gravito-turbulence and dynamo in poorly ionised protostellar discs. I. Zero-net-flux case
• Shedding light on the MRI driven dynamo in a stratified shearing box
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• Unified treatment of mean-field dynamo and angular-momentum transport in magnetorotational instability-driven turbulence
• Ribbons characterize magnetohydrodynamic magnetic fields better than lines: a lesson from dynamo theory
• Transport properties of Keplerian flows in extended local domains with no imposed field
• A 2.5-dimensional viscous, resistive, advective magnetized accretion-outflow coupling in black hole systems: A higher order polynomial approximation. I
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• Electromotive field in space and astrophysical plasmas
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