Turbulence In the Outer Regions of Protoplanetary Disks. I. Weak Accretion with No Vertical Magnetic Flux

Abstract

We use local numerical simulations to investigate the strength and nature of magnetohydrodynamic (MHD) turbulence in the outer regions of protoplanetary disks, where ambipolar diffusion is the dominant non-ideal MHD effect. The simulations include vertical stratification and assume zero net vertical magnetic flux. We employ a super time-stepping technique to ameliorate the Courant restriction on the diffusive time step. We find that in idealized stratified simulations, with a spatially constant ambipolar Elsasser number Am, turbulence driven by the magnetorotational instability (MRI) behaves in a similar manner as in prior unstratified calculations. Turbulence dies away for Am < 1, and becomes progressively more vigorous as ambipolar diffusion is decreased. Near-ideal MHD behavior is recovered for Am > 1000. In the intermediate regime (10 < Am < 1000) ambipolar diffusion leads to substantial increases in both the period of the MRI dynamo cycle and the characteristic scales of magnetic field structures. To quantify the impact of ambipolar physics on disk accretion, we run simulations at 30 AU and 100 AU that include a vertical Am profile based upon far ultraviolet (FUV) ionized disk models. These models develop a vertically layered structure analogous to the Ohmic dead zone that is present at smaller radii. We find that, although the levels of surface turbulence can be strong (and consistent with constraints on turbulent line widths at these radii), the inferred accretion rates are at least an order of magnitude smaller than those observed in T Tauri stars. This discrepancy is very likely due to the assumption of zero vertical magnetic field in our simulations and suggests that vertical magnetic fields are essential for MRI-driven accretion in the outer regions of protoplanetary disks.

accepted to ApJ after minor revisions

References in corpus (14)

• Athena: A New Code for Astrophysical MHD
• Particle Stirring in Turbulent Gas Disks: Including Orbital Oscillations
• Closed-form expressions for particle relative velocities induced by turbulence
• An Unsplit Godunov Method for Ideal MHD via Constrained Transport in Three Dimensions
• Dust size distributions in coagulation/fragmentation equilibrium: Numerical solutions and analytical fits
• MHD simulations of the magnetorotational instability in a shearing box with zero net flux. I. The issue of convergence
• Dead Zone Accretion Flows in Protostellar Disks
• The magnetorotational instability as a jet launching mechanism
• Accretion and destruction of planetesimals in turbulent disks
• 3D MHD Simulations of Planet Migration in Turbulent Stratified Disks
• A Simple and Accurate Riemann Solver for Isothermal MHD
• A three-dimensional numerical method for modelling weakly ionized plasmas
• An Explicit Scheme for Incorporating Ambipolar Diffusion in a Magnetohydrodynamics Code
• Turbulent Linewidths as a Diagnostic of Self-Gravity in Protostellar Discs

Cited by in corpus (93)

• Wind-driven Accretion in Protoplanetary Disks. I: Suppression of the Magnetorotational Instability and Launching of the Magnetocentrifugal Wind
• Thanatology in Protoplanetary Discs: the combined influence of Ohmic, Hall, and ambipolar diffusion on dead zones
• Towards a Global Evolutionary Model of Protoplanetary Disks
• Hall-effect Controlled Gas Dynamics in Protoplanetary Disks: II. Full 3D Simulations toward the Outer Disk
• Magneto-thermal Disk Wind from Protoplanetary Disks
• Turbulence In the Outer Regions of Protoplanetary Disks. II. Strong Accretion Driven by a Vertical Magnetic Field
• Global Simulations of the Inner Regions of Protoplanetary Disks with Comprehensive Disk Microphysics
• Cooling Requirements for the Vertical Shear Instability in Protoplanetary Disks
• Magnetically driven accretion in protoplanetary discs
• Global Evolution of an Accretion Disk with Net Vertical Field: Coronal Accretion, Flux Transport, and Disk Winds
• Hall-effect Controlled Gas Dynamics in Protoplanetary Disks: I. Wind Solutions at the Inner Disk
• Magnetic self-organisation in Hall-dominated magnetorotational turbulence
• Wind-driven Accretion in Protoplanetary Disks --- II: Radial Dependence and Global Picture
• Transport of CO in Protoplanetary Disks: Consequences of Pebble Formation, Settling, and Radial Drift
• Magnetized Accretion and Dead Zones in Protostellar Disks
• Global Simulations of Protoplanetary Disk Outflows with Coupled Non-ideal Magnetohydrodynamics and Consistent Thermochemistry
• Composition of Early Planetary Atmospheres I: Connecting Disk Astrochemistry to the Formation of Planetary Atmospheres
• Hall-effect Mediated Magnetic Flux Transport in Protoplanetary Disks
• Diffusion and Concentration of Solids in the Dead Zone of a Protoplanetary Disk
• Protoplanetary Disks as (Possibly) Viscous Disks
• On the physical nature of accretion disc viscosity
• Saturation of the magnetorotational instability in the unstratified shearing box with zero net flux: convergence in taller boxes
• How Bright are Planet-Induced Spiral Arms in Scattered Light?
• Global Three-Dimensional Simulations of Outer Protoplanetary Disks with Ambipolar Diffusion
• Protoplanetary Disk Sizes and Angular Momentum Transport
• Radiation Hydrodynamics Simulations of Photoevaporation of Protoplanetary Disks by Ultra Violet Radiation: Metallicity Dependence
• Turbulence Regulates the Rate of Planetesimal Formation via Gravitational Collapse
• The formation of rings and gaps in wind-launching non-ideal MHD disks: three-dimensional simulations
• Two timescale dispersal of magnetized protoplanetary disks
• Radial Transport of Large-Scale Magnetic Fields in Accretion Disks. I. Steady Solutions and an Upper Limit on the Vertical Field Strength
• Signatures of MRI-Driven Turbulence in Protoplanetary Disks: Predictions for ALMA Observations
• Efficiency of Particle Trapping in the Outer Regions of Protoplanetary Disks
• Bipolar jets launched from accretion disks. II. Formation of symmetric and asymmetric jets and counter jets
• ALMA Dust Polarization Observations of Two Young Edge-on Protostellar Disks
• Predicted diversity in water content of terrestrial exoplanets orbiting M dwarfs
• The formation of systems with closely spaced low-mass planets and the application to Kepler-36
• Steady-state accretion in magnetized protoplanetary disks
• On the evolution of the snow line in protoplanetary discs II: Analytic approximations
• Origin of Weak Turbulence in the Outer Regions of Protoplanetary Disks
• Formation of circumbinary planets in a dead zone
• Wind-driven Accretion in Transitional Protostellar Disks
• Global Simulations of the Vertical Shear Instability with Non-ideal Magnetohydrodynamical Effects
• Gravito-Turbulent Disks in 3D: Turbulent Velocities vs. Depth
• Fossil magnetic field of accretion disks of young stars
• Magnetically Induced Disk Winds and Transport in the HL Tau Disk
• On the Formation and Chemical Composition of Super Earths
• Propagation of the Gravo-Magneto Disc Instability
• Stability and Occurrence Rate Constraints on the Planetary Sculpting Hypothesis for "Transitional" Disks
• Dust Settling and Clumping in MRI Turbulent Outer Protoplanetary Disks
• Determining the mid-plane conditions of circumstellar discs using gas and dust modelling: a study of HD 163296
• Pebble accretion at the origin of water in Europa
• The magnetorotational instability in debris-disc gas
• On the Grain-Modified Magnetic Diffusivities in Protoplanetary Disks
• Why are pulsar planets rare?
• Dust segregation in Hall-dominated turbulent protoplanetary disks
• Photoevaporation of Grain-Depleted Protoplanetary Disks around Intermediate-Mass Stars: Investigating Possibility of Gas-Rich Debris Disks as Protoplanetary Remnants
• Turbulence in outer protoplanetary disks: MRI or VSI?
• Formation of Planetary Populations I: Metallicity & Envelope Opacity Effects
• The impact of dynamic pressure bumps on the observational properties of protoplanetary disks
• Effects of Dust Evolution on the Vertical Shear Instability in the Outer Regions of Protoplanetary Disks
• The gravo-magneto disc instability with a viscous dead zone
• Magnetised Winds in Transition Discs I: 2.5D Global Simulations
• The Nonlinear Ohm's Law: Plasma Heating by Strong Electric Fields and its Effects on the Ionization Balance in Protoplanetary Disks
• On the Vertical Shear Instability in Magnetized Protoplanetary Disks
• Electron Heating in the Magnetorotational Instability: Implications for Turbulence Strength in Outer Regions of Protoplanetary Disks
• Physics of Planet Trapping with Applications to HL Tau
• Magnetorotational instability with smoothed particle hydrodynamics
• FUV Irradiation and the Heat Signature of Accretion in Protoplanetary Disk Atmospheres
• Two saturated states of the vertical shear instability in protoplanetary disks with vertically varying cooling times
• Formation of Planetary Populations II: Effects of Initial Disk Size & Radial Dust Drift
• Magnetohydrodynamics of protoplanetary discs
• Sensitivity of the Magnetorotational Instability to the shear parameter in stratified simulations
• Turbulence, Transport and Waves in Ohmic Dead Zones
• Growth of Magnetorotational Instability in Circumstellar Disks around Class 0 Protostars
• Combined Effects of Disk Winds and Turbulence-Driven Accretion on Planet Populations
• Disk evolution and the fate of water
• MRI-driven angular momentum transport in protoplanetary disks
• Viscous Instability Triggered by Layered Accretion in Protoplanetary Disks
• United Theory of Planet Formation (I): Tandem Regime
• Effect of Different Angular Momentum Transport mechanisms on the Distribution of Water in Protoplanetary Disks
• The Generalized Nonlinear Ohm's Law: How a Strong Electric Field Influences Non-ideal MHD Effects in Dusty Protoplanetary Disks
• Birth of magnetized low-mass protostars and circumstellar disks
• Global magnetohydrodynamic simulations of the inner regions of protoplanetary discs. I. Zero-net flux regime
• Structure of Protoplanetary Discs with Magnetically-driven Winds
• Importance of thermal diffusion in the gravo-magnetic limit cycle
• Radially Magnetized Protoplanetary Disk: Vertical Profile
• Nebular dead zone effects on the D/H ratio in chondrites and comets
• Time-dependent evolution of the protoplanetary discs with magnetic winds
• Rossby wave instability in weakly ionized protoplanetary disks. II. radial B-fields
• The Nature of Turbulence in the Outer Regions of Protoplanetary Disks
• The Influence of Magnetic Field Geometry on the Formation of Close-in Exoplanets
• Global magnetohydrodynamic simulations of the inner regions of protoplanetary discs. II. Vertical-net-flux regime
• Global Non-ideal Magnetohydrodynamic Simulations of Protoplanetary Disks with Outer Truncation