Rings and gaps produced by variable magnetic disk winds and avalanche accretion streams: I. Axisymmetric resistive MHD simulations

Abstract

Rings and gaps are being observed in an increasing number of disks around young stellar objects. We illustrate the formation of such radial structures through idealized, 2D (axisymmetric) resistive MHD simulations of coupled disk-wind systems threaded by a relatively weak poloidal magnetic field (plasma-$\beta \sim 10^3$). We find two distinct modes of accretion depending on the resistivity and field strength. A small resistivity or high field strength promotes the development of rapidly infalling `avalanche accretion streams' in a vertically extended disk envelope that dominates the dynamics of the system, especially the mass accretion. The streams are suppressed in simulations with larger resistivities or lower field strengths, where most of the accretion instead occurs through a laminar disk. In these simulations, the disk accretion is driven mainly by a slow wind that is typically accelerated by the pressure gradient from a predominantly toroidal magnetic field. Both wind-dominated and stream-dominated modes of accretion create prominent features in the surface density distribution of the disk, including rings and gaps, with a strong spatial variation of the magnetic flux relative to the mass. Regions with low mass-to-flux ratios accrete quickly, leading to the development of gaps, whereas regions with higher mass-to-flux ratios tend to accrete more slowly, allowing matter to accumulate and form dense rings. In some cases, avalanche accretion streams are observed to produce dense rings directly through continuous feeding. We discuss the implications of ring and gap formation driven by winds and streams on grain growth and planet formation.

23 pages, 10 figures, accepted by MNRAS

References in corpus (12)

• Gaps, Rings, and Non-Axisymmetric Structures in Protoplanetary Disks - From Simulations to ALMA Observations
• Global simulations of protoplanetary disks with ohmic resistivity and ambipolar diffusion
• Evolution of Protoplanetary Discs with Magnetically Driven Disc Winds
• MHD simulations of jet acceleration from Keplerian accretion disks: the effects of disk resistivity
• Accretion-Powered Stellar Winds II: Numerical Solutions for Stellar Wind Torques
• Resolved images of a protostellar outflow launched by an extended disk wind
• Magnetic Flux Concentration and Zonal Flows in Magnetorotational Instability Turbulence
• Tracing Slow Winds from T Tauri Stars via Low Velocity Forbidden Line Emission
• Hall-effect Mediated Magnetic Flux Transport in Protoplanetary Disks
• Rotating molecular outflows: the young T Tauri star in CB26
• Disk Formation Enabled by Enhanced Resistivity
• Modelling MHD accretion-ejection - from the launching area to propagation scales

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• Global Hydromagnetic Simulations of Protoplanetary Disks with Stellar Irradiation and Simplified Thermochemistry
• Spontaneous ring formation in wind-emitting accretion discs
• Magnetically Induced Disk Winds and Transport in the HL Tau Disk
• Constraining Protoplanetary Disk Accretion and Young Planets Using ALMA Kinematic Observations
• On the Dust Signatures Induced by Eccentric Super-Earths in Protoplanetary Disks
• MHD simulations of the formation and propagation of protostellar jets to observational length scales
• Local semi-analytic models of magnetic flux transport in protoplanetary discs
• Dust ring and gap formation by gas flow induced by low-mass planets embedded in protoplanetary disks $\mathrm{I}$. Steady-state model
• Wind-MRI interactions in local models of protoplanetary discs: I. Ohmic resistivity