Global magnetohydrodynamical models of turbulence in protoplanetary disks I. A cylindrical potential on a Cartesian grid and transport of solids

TL;DR

This paper develops global 3D magnetohydrodynamic simulations of protoplanetary disks with solids, demonstrating the effectiveness of Cartesian grid codes and analyzing turbulence and solid concentration effects relevant to planet formation.

Contribution

It introduces a Cartesian grid approach for global disk MHD simulations and explores how magnetorotational turbulence depends on disk thermal pressure and influences solid particle dynamics.

Findings

Turbulence growth scales with thermal pressure, following a power law of 0.24.

Turbulent stresses decrease as temperature increases.

Solid particles concentrate in high-pressure regions, forming overdensities.

Abstract

We present global 3D MHD simulations of disks of gas and solids, aiming at developing models that can be used to study various scenarios of planet formation and planet-disk interaction in turbulent accretion disks. A second goal is to show that Cartesian codes are comparable to cylindrical and spherical ones in handling the magnetohydrodynamics of the disk simulations, as the disk-in-a-box models presented here develop and sustain MHD turbulence. We investigate the dependence of the magnetorotational instability on disk scale height, finding evidence that the turbulence generated by the magnetorotational instability grows with thermal pressure. The turbulent stresses depend on the thermal pressure obeying a power law of 0.24+/-0.03, compatible with the value of 0.25 found in shearing box calculations. The ratio of stresses decreased with increasing temperature. We also study the dynamics of boulders in the hydromagnetic turbulence. The vertical turbulent diffusion of the embedded boulders is comparable to the turbulent viscosity of the flow. Significant overdensities arise in the solid component as boulders concentrate in high pressure regions.