Global Structure of Magnetorotationally Turbulent Protoplanetary Discs

TL;DR

This paper uses detailed 3D chemo-radiative MHD simulations to reveal the global spatial structure of magnetorotationally turbulent protoplanetary discs, including the formation of a dead zone between 2 and 4 AU.

Contribution

It provides the first physically realistic simulation-based derivation of the global structure of a protoplanetary disc with magnetorotational turbulence.

Findings

Identification of a non-turbulent dead zone between 2 and 4 AU.

Demonstration of ionisation effects on turbulence and magnetic coupling.

Global spatial structure derived from realistic simulations.

Abstract

The aim of the present paper is to investigate the spatial structure of a protoplanetary disc whose dynamics is governed by magnetorotational turbulence. We perform a series of local 3D chemo-radiative MHD simulations located at different radii of a disc which is twice as massive as the standard minimum mass solar nebula of Hayashi (1981). The ionisation state of the disc is calculated by including collisional ionisation, stellar X-rays, cosmic rays and the decay of radionuclides as ionisation sources, and by solving a simplified chemical network which includes the effect of the absorption of free charges by {\mu}m-sized dust grains. In the region where the ionisation is too low to assure good coupling between matter and magnetic fields, a non-turbulent central "dead zone" forms, which ranges approximately from a distance of 2 AU to 4 AU from the central star. The approach taken in the present work allows for the first time to derive the global spatial structure of a protoplanetary disc from a set of physically realistic numerical simulations.