Unified treatment of mean-field dynamo and angular-momentum transport in magnetorotational instability-driven turbulence
arXiv:2307.01281 · doi:10.1103/PhysRevE.108.065201
Abstract
Magnetorotational instability (MRI)-driven turbulence and dynamo phenomena are analyzed using direct statistical simulations. Our approach begins by developing a unified mean-field model that combines the traditionally decoupled problems of the large-scale dynamo and angular-momentum transport in accretion disks. The model consists of a hierarchical set of equations, capturing up to the second-order cumulants, while a statistical closure approximation is employed to model the three-point correlators. We highlight the web of interactions that connect different components of stress tensors -- Maxwell, Reynolds, and Faraday -- through shear, rotation, correlators associated with mean fields, and nonlinear terms. We determine the dominant interactions crucial for the development and sustenance of MRI turbulence. Our general mean field model for the MRI-driven system allows for a self-consistent construction of the electromotive force, inclusive of inhomogeneities and anisotropies. Within the realm of large-scale magnetic field dynamo, we identify two key mechanisms -- the rotation-shear-current effect and the rotation-shear-vorticity effect -- that are responsible for generating the radial and vertical magnetic fields, respectively. We provide the explicit (nonperturbative) form of the transport coefficients associated with each of these dynamo effects. Notably, both of these mechanisms rely on the intrinsic presence of large-scale vorticity dynamo within MRI turbulence.
arXiv comment32 pages including 25 figures; Version accepted for publication in Phys. Rev. E
References in corpus (58)
- Astrophysical magnetic fields and nonlinear dynamo theory
- First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near The Event Horizon
- Sustained Magnetorotational Turbulence in Local Simulations of Stratified Disks with Zero Net Magnetic Flux
- The Pencil Code, a modular MPI code for partial differential equations and particles: multipurpose and multiuser-maintained
- Magnetic diffusivity tensor and dynamo effects in rotating and shearing turbulence
- Electromotive Force and Large-Scale Magnetic Dynamo in a Turbulent Flow with a Mean Shear
- Direct simulations of a supernova-driven galactic dynamo
- An Incoherent Dynamo in Accretion Disks
- Nonlinear theory of a "shear-current" effect and mean-field magnetic dynamos
- Testing Convergence for Global Accretion Disks
- Generation of Magnetic Field by Combined Action of Turbulence and Shear
- Cross helicity and related dynamo
- Statistics of an Unstable Barotropic Jet from a Cumulant Expansion
- On Self-Sustained Dynamo Cycles in Accretion Discs
- Advances in mean-field dynamo theory and applications to astrophysical turbulence
- On the dynamics of magnetorotational turbulent stresses
- The mean electromotive force due to turbulence of a conducting fluid in the presence of mean flow
- Saturation of the magnetorotational instability in the unstratified shearing box with zero net flux: convergence in taller boxes
- Large-Scale Magnetic-Field Generation by Randomly Forced Shearing Waves
- Turbulence in Global Simulations of Magnetized Thin Accretion Disks
- Effects of fluctuation on alpha-omega dynamo models
- Characterizing the mean-field dynamo in turbulent accretion disks
- Large-scale Dynamo Action Driven by Velocity Shear and Rotating Convection
- Low-Frequency Oscillations in Global Simulations of Black Hole Accretion
- Galactic Dynamos
- A Local Model for Angular Momentum Transport in Accretion Disks Driven by the Magnetorotational Instability
- Generation of large-scale magnetic fields by small-scale dynamo in shear flows
- Do mean-field dynamos in nonrotating turbulent shear-flows exist?
- The fundamental difference between shear alpha viscosity and turbulent magnetorotational stresses
- On self-sustaining processes in Rayleigh-stable rotating plane Couette flows and subcritical transition to turbulence in accretion disks
- A mean-field approach to the propagation of field patterns in stratified magneto rotational turbulence
- Statistical simulation of the magnetorotational dynamo
- Scaling and intermittency in incoherent α-shear dynamo
- The influence of accretion disk thickness on the large-scale magnetic dynamo
- Subcritical dynamos in shear flows
- Global simulations of magnetorotational turbulence I: convergence and the quasi-steady state
- Large scale dynamo action precedes turbulence in shearing box simulations of the magnetorotational instability
- Nonperturbative quasilinear approach to the shear dynamo problem
- Electromotive force due to magnetohydrodynamic fluctuations in sheared rotating turbulence
- Large-scale dynamo action due to fluctuations in a linear shear flow
- Characterising the Dynamo in a Radiatively Inefficient Accretion Flow
- Transport coefficients for the shear dynamo problem at small Reynolds numbers
- On the magnetic quenching of mean-field effects in supersonic interstellar turbulence
- Coherent nonhelical shear dynamos driven by magnetic fluctuations at low Reynolds numbers
- Turbulent transport coefficients in galactic dynamo simulations using singular value decomposition
- Magnetorotational instability with smoothed particle hydrodynamics
- Simulating the magnetorotational instability on a moving mesh with the shearing box approximation
- Magnetic helicity fluxes from triple correlators
- Mean magnetic field generation in sheared rotators
- Motivation and challenge to capture both large scale and local transport in next generation accretion theory
- Radially Dependent Large Scale Dynamos in Global Cylindrical Shear Flows and the Local Cartesian Limit
- Comparisons and Connections between Mean Field Dynamo Theory and Accretion Disc Theory
- Compressible test-field method and its application to shear dynamos
- Turbulent stresses as a function of shear rate in a local disk model
- Mean electromotive force proportional to mean flow in mhd turbulence
- On the shear-current effect: toward understanding why theories and simulations have mutually and separately conflicted
- On the existence of shear-current effects in magnetized burgulence
- Evolution of the magnetorotational instability on initially tangled magnetic fields