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Title: Global Simulations of the Inner Regions of Protoplanetary Disks with Comprehensive Disk Microphysics

Abstract

The gas dynamics of weakly ionized protoplanetary disks (PPDs) are largely governed by the coupling between gas and magnetic fields, described by three non-ideal magnetohydrodynamical (MHD) effects (Ohmic, Hall, ambipolar). Previous local simulations incorporating these processes have revealed that the inner regions of PPDs are largely laminar and accompanied by wind-driven accretion. We conduct 2D axisymmetric, fully global MHD simulations of these regions (∼1–20 au), taking into account all non-ideal MHD effects, with tabulated diffusion coefficients and approximate treatment of external ionization and heating. With the net vertical field aligned with disk rotation, the Hall-shear instability strongly amplifies horizontal magnetic field, making the overall dynamics dependent on initial field configuration. Following disk formation, the disk likely relaxes into an inner zone characterized by asymmetric field configuration across the midplane, which smoothly transitions to a more symmetric outer zone. Angular momentum transport is driven by both MHD winds and laminar Maxwell stress, with both accretion and decretion flows present at different heights, and modestly asymmetric winds from the two disk sides. With anti-aligned field polarity, weakly magnetized disks settle into an asymmetric field configuration with supersonic accretion flow concentrated at one side of the disk surface, and highly asymmetric winds betweenmore » the two disk sides. In all cases, the wind is magneto-thermal in nature, characterized by a mass loss rate exceeding the accretion rate. More strongly magnetized disks give more symmetric field configuration and flow structures. Deeper far-UV penetration leads to stronger and less stable outflows. Implications for observations and planet formation are also discussed.« less

Authors:
 [1]
  1. Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden St., MS-51, Cambridge, MA 02138 (United States)
Publication Date:
OSTI Identifier:
22663258
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 845; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; ANGULAR MOMENTUM; APPROXIMATIONS; ASYMMETRY; AXIAL SYMMETRY; DIFFUSION; INSTABILITY; IONIZATION; MAGNETIC FIELDS; MAGNETOHYDRODYNAMICS; MASS TRANSFER; PLANETS; PROTOPLANETS; SATELLITES; SIMULATION; STELLAR WINDS

Citation Formats

Bai, Xue-Ning, E-mail: xbai@cfa.harvard.edu. Global Simulations of the Inner Regions of Protoplanetary Disks with Comprehensive Disk Microphysics. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA7DDA.
Bai, Xue-Ning, E-mail: xbai@cfa.harvard.edu. Global Simulations of the Inner Regions of Protoplanetary Disks with Comprehensive Disk Microphysics. United States. doi:10.3847/1538-4357/AA7DDA.
Bai, Xue-Ning, E-mail: xbai@cfa.harvard.edu. Thu . "Global Simulations of the Inner Regions of Protoplanetary Disks with Comprehensive Disk Microphysics". United States. doi:10.3847/1538-4357/AA7DDA.
@article{osti_22663258,
title = {Global Simulations of the Inner Regions of Protoplanetary Disks with Comprehensive Disk Microphysics},
author = {Bai, Xue-Ning, E-mail: xbai@cfa.harvard.edu},
abstractNote = {The gas dynamics of weakly ionized protoplanetary disks (PPDs) are largely governed by the coupling between gas and magnetic fields, described by three non-ideal magnetohydrodynamical (MHD) effects (Ohmic, Hall, ambipolar). Previous local simulations incorporating these processes have revealed that the inner regions of PPDs are largely laminar and accompanied by wind-driven accretion. We conduct 2D axisymmetric, fully global MHD simulations of these regions (∼1–20 au), taking into account all non-ideal MHD effects, with tabulated diffusion coefficients and approximate treatment of external ionization and heating. With the net vertical field aligned with disk rotation, the Hall-shear instability strongly amplifies horizontal magnetic field, making the overall dynamics dependent on initial field configuration. Following disk formation, the disk likely relaxes into an inner zone characterized by asymmetric field configuration across the midplane, which smoothly transitions to a more symmetric outer zone. Angular momentum transport is driven by both MHD winds and laminar Maxwell stress, with both accretion and decretion flows present at different heights, and modestly asymmetric winds from the two disk sides. With anti-aligned field polarity, weakly magnetized disks settle into an asymmetric field configuration with supersonic accretion flow concentrated at one side of the disk surface, and highly asymmetric winds between the two disk sides. In all cases, the wind is magneto-thermal in nature, characterized by a mass loss rate exceeding the accretion rate. More strongly magnetized disks give more symmetric field configuration and flow structures. Deeper far-UV penetration leads to stronger and less stable outflows. Implications for observations and planet formation are also discussed.},
doi = {10.3847/1538-4357/AA7DDA},
journal = {Astrophysical Journal},
number = 1,
volume = 845,
place = {United States},
year = {Thu Aug 10 00:00:00 EDT 2017},
month = {Thu Aug 10 00:00:00 EDT 2017}
}