On the Magnetic Prandtl Number Behavior of Accretion Disks

Abstract

We investigate the behavior of the magnetic Prandtl number (ratio of microscopic viscosity to resistivity) for accretion sources. Generally this number is very small in standard accretion disk models, but can become larger than unity within $\sim 50$ Schwarzschild radii of the central mass. Recent numerical investigations suggest a marked dependence of the level of MHD turbulence on the value of the Prandtl number. Hence, black hole and neutron star accretors, i.e. compact X-ray sources, are affected. The astrophysical consequences of this could be significant, including a possible route to understanding the mysterious state changes that have long characterized these sources.

arXiv comment15 pages, 6 figures. Accepted for publication in the Astrophysical Journal (February 10, 2008 issue.) Minor changes from original submission

References in corpus (10)

• Advection-Dominated Accretion: Underfed Black Holes and Neutron Stars
• The inverse cascade and nonlinear alpha-effect in simulations of isotropic helical hydromagnetic turbulence
• Simulations of small-scale turbulent dynamo
• A long hard look at MCG-6-30-15 with XMM-Newton
• 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
• Critical Protoplanetary Core Masses in Protoplanetary Disks and the Formation of Short-Period Giant Planets
• Fluctuation dynamo and turbulent induction at low magnetic Prandtl numbers
• Numerical demonstration of fluctuation dynamo at low magnetic Prandtl numbers
• The onset of a small-scale turbulent dynamo at low magnetic Prandtl numbers

Cited by in corpus (74)

• Zonal Flows and Long-Lived Axisymmetric Pressure Bumps in Magnetorotational Turbulence
• The Event Horizon General Relativistic Magnetohydrodynamic Code Comparison Project
• Phase Diagram for Magnetic Reconnection in Heliophysical, Astrophysical and Laboratory Plasmas
• Black hole-like hysteresis and accretion states in neutron star low mass X-ray binaries
• Magnetic self-organisation in Hall-dominated magnetorotational turbulence
• The Turbulent Magnetic Prandtl Number of MHD Turbulence in Disks
• Resistivity-driven State Changes in Vertically Stratified Accretion Disks
• Helical magnetorotational instability in a Taylor-Couette flow with strongly reduced Ekman pumping
• On Self-Sustained Dynamo Cycles in Accretion Discs
• Magnetohydrodynamic experiments on cosmic magnetic fields
• Plasmoid Instability in Forming Current Sheets
• A mechanism for hysteresis in black hole binary state transitions
• Global bifurcations to subcritical magnetorotational dynamo action in Keplerian shear flow
• High accretion rates in magnetised Keplerian discs mediated by a Parker instability driven dynamo
• Dissipation and Vertical Energy Transport in Radiation-Dominated Accretion Disks
• Viscous and Resistive Effects on the MRI with a Net Toroidal Field
• Characterizing the mean-field dynamo in turbulent accretion disks
• Angular Momentum Transport in Protoplanetary and Black-Hole Accretion Disks: The Role of Parasitic Modes in the Saturation of MHD Turbulence
• Viscous, Resistive Magnetorotational Modes
• Nonlinear energy transfers in accretion discs MRI turbulence. I-Net vertical field case
• Magnetorotational turbulence transports angular momentum in stratified disks with low magnetic Prandtl number but magnetic Reynolds number above a critical value
• Angular momentum transport and large eddy simulations in magnetorotational turbulence: the small Pm limit
• On the Nature of Magnetic Turbulence in Rotating, Shearing Flows
• On the relation of standard and helical magnetorotational instability
• Saturation of the MRI in Strongly Radiation Dominated Accretion Disks
• An accretion disk-outflow model for hysteretic state transition in X-ray binaries
• Extending the range of the inductionless magnetorotational instability
• Gravitoturbulent dynamos in astrophysical discs
• Axisymmetric Magnetorotational Instability in Viscous Accretion Disks
• Dissipative effects on the sustainment of a magnetorotational dynamo in Keplerian shear flow
• An Atlas of Convection in Main-Sequence Stars
• Magnetorotational dynamo chimeras. The missing link to turbulent accretion disk dynamo models?
• MRI-driven dynamo at very high magnetic Prandtl numbers
• A unifying picture of helical and azimuthal MRI, and the universal significance of the Liu limit
• An accretion disc instability induced by a temperature sensitive $\alpha$ parameter
• A spectral Galerkin method for the coupled Orr-Sommerfeld and induction equations for free-surface MHD
• Destabilization of rotating flows with positive shear by azimuthal magnetic fields
• A MAD Model for Gamma-Ray Burst Variability
• MRI turbulence in accretion discs at large magnetic Prandtl numbers
• Dissipation in dynamos at low and high magnetic Prandtl numbers
• Microphysical dissipation, turbulence and magnetic fields in hyper-accreting discs
• Compressible streaming instabilities in rotating thermal viscous objects
• On properties of Velikhov-Chandrasekhar MRI in ideal and non-ideal plasma
• Singular diffusionless limits of double-diffusive instabilities in magnetohydrodynamics
• The connection between the UV/optical and X-ray emission in the neutron star low-mass X-ray binary Aql X-1
• Interaction of the magnetorotational instability with hydrodynamic turbulence in accretion disks
• Linking dissipation-induced instabilities with nonmodal growth: the case of helical magnetorotational instability
• A Transparent Window into Early-Type Stellar Variability
• Standard and helical magnetorotational instability: How singularities create paradoxal phenomena in MHD
• Global simulations of magnetorotational turbulence II: turbulent energetics
• Magnetically Advected Winds
• Post-dynamical inspiral phase of common envelope evolution. The role of magnetic fields
• Magnetic field structure in the vicinity of a super-massive black hole in low luminosity galaxies: the case of Sgr A*
• Demonstration of a magnetic Prandtl number disc instability from first principles
• Stability of MRI turbulent Accretion Disks
• Magnetorotationally driven wind cycles in local disc models
• Stratified Global MHD Models of Accretion Disks in Semi-Detached Binaries
• MRI turbulence in vertically stratified accretion discs at large magnetic Prandtl numbers
• Large-wavelength instabilities in free-surface Hartmann flow at low magnetic Prandtl numbers
• Gravito-turbulence and dynamo in poorly ionised protostellar discs. I. Zero-net-flux case
• Chaotic behavior of Eulerian MHD turbulence
• A systematic route to subcritical dynamo branches
• Neutrino-Dominated Accretion Flows with Magnetic Prandtl Number-Dependent MRI-driven Turbulence
• Electromagnetic instabilities in rotating magnetized viscous objects
• Low magnetic-Prandtl number flow configurations for cold astrophysical disk models: speculation and analysis
• Instabilities of rotational flows in azimuthal magnetic fields of arbitrary radial dependence
• Fully resolved array of simulations investigating the influence of the magnetic Prandtl number on magnetohydrodynamic turbulence
• Analysis of azimuthal magnetorotational instability of rotating MHD flows and Tayler instability via an extended Hain-Lust equation
• Self-similar structure of resistive ADAFs with outflow and large-scale magnetic field
• Behavior of thin disk crystalline morphology in the presence of corrections to ideal magnetohydrodynamics
• Laboratory modeling of MHD accretion disks
• MRI-driven $\alpha \Omega$ dynamo at high Pm numbers
• A Monte Carlo Study of the Spectra from Inhomogeneous Accretion Flow
• Fast giant flares in discs around supermassive black holes