Global multifluid simulations of the magnetorotational instability in radially stratified protoplanetary disks

Abstract

The redistribution of angular momentum is a long standing problem in our understanding of protoplanetary disk (PPD) evolution. The magnetorotational instability (MRI) is considered a likely mechanism. We present the results of a study involving multifluid global simulations including Ohmic dissipation, ambipolar diffusion and the Hall effect in a dynamic, self-consistent way. We focus on the turbulence resulting from the non-linear development of the MRI in radially stratified PPDs and compare with ideal MHD simulations. In the multifluid simulations the disk is initially set up to transition from a weak Hall dominated regime, where the Hall effect is the dominant non-ideal effect but approximately the same as or weaker than the inductive term, to a strong Hall dominated regime, where the Hall effect dominates the inductive term. As the simulations progress a substantial portion of the disk develops into a weak Hall dominated disk. We find a transition from turbulent to laminar flow in the inner regions of the disk, but without any corresponding overall density feature. We introduce a dimensionless parameter, ${\alpha }_{\mathrm{RM}}$, to characterise accretion with ${\alpha }_{\mathrm{RM}}\gtrsim 0.1$ corresponding to turbulent transport. We calculate the eddy turnover time, $t_{\mathrm{eddy}}$, and compared this with an effective recombination timescale, $t_{\mathrm{rcb}}$, to determine whether the presence of turbulence necessitates non-equilibrium ionisation calculations. We find that $t_{\mathrm{rcb}}$ is typically around three orders of magnitude smaller than $t_{\mathrm{eddy}}$. Also, the ionisation fraction does not vary appreciably. These two results suggest that these multifluid simulations should be comparable to single fluid non-ideal simulations.

13 pages, 12 figures, 1 table, accepted for publication in MNRAS

References in corpus (10)

• A comparative study of disc-planet interaction
• MHD simulations of the magnetorotational instability in a shearing box with zero net flux. I. The issue of convergence
• Hall-effect Controlled Gas Dynamics in Protoplanetary Disks: II. Full 3D Simulations toward the Outer Disk
• Global MHD simulations of stratified and turbulent protoplanetary discs. I. Model properties
• Global magnetohydrodynamical models of turbulence in protoplanetary disks I. A cylindrical potential on a Cartesian grid and transport of solids
• A three-dimensional numerical method for modelling weakly ionized plasmas
• Angular momentum transport in protostellar discs
• On the convergence of Magnetorotational turbulence in stratified isothermal shearing boxes
• Multifluid simulations of the Magnetorotational Instability in protostellar disks
• Cosmic-ray pressure driven magnetic field amplification: dimensional, radiative and field orientation effects

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