Global Simulations of Protoplanetary Disk Outflows with Coupled Non-ideal Magnetohydrodynamics and Consistent Thermochemistry

TL;DR

This study presents comprehensive global MHD simulations of protoplanetary disk outflows, incorporating thermochemistry and non-ideal effects, revealing how magnetic fields and radiation influence wind properties and disk dispersal.

Contribution

It introduces a coupled simulation approach with thermochemistry and non-ideal MHD, providing new insights into magnetized disk winds driven by magnetic pressure rather than centrifugally.

Findings

Outflows have poloidal speeds ≥ 4 km/s and are driven by magnetic pressure.

Wind mass-loss rates are comparable to accretion rates at certain magnetizations.

Ionization from UV and X-ray radiation significantly affects wind dynamics.

Abstract

Magnetized winds may be important in dispersing protoplanetary disks and influencing planet formation. We carry out global full magnetohydrodynamic simulations in axisymmetry, coupled with ray-tracing radiative transfer, consistent thermochemistry, and non-ideal MHD diffusivities. Magnetized models lacking EUV photons ($h\nu>13.6\ \mathrm{eV}$) feature warm molecular outflows that have typical poloidal speeds $\gtrsim 4\ \mathrm{km\ s}^{-1}$. When the magnetization is sufficient to drive accretion rates $\sim 10^{-8}\ M_\odot\ \mathrm{yr}^{-1}$, the wind mass-loss rate is comparable. Such outflows are driven not centrifugally but by the pressure of toroidal magnetic fields produced by bending the poloidal field. Both the accretion and outflow rates increase with the poloidal field energy density, the former almost linearly. The mass-loss rate is also strongly affected by ionization due to UV and X-ray radiation near the wind base. Adding EUV irradiation to the system heats, ionizes, and accelerates the part of the outflow nearest the symmetry axis, but reduces the overall mass-loss rate by exerting pressure on the wind base. Most of our models are non-turbulent, but some with reduced dust abundance and therefore higher ionization fractions exhibit magnetorotational instabilities near the base of the wind.