Gravitoturbulence in magnetised protostellar discs

Abstract

Gravitational instability (GI) features in several aspects of protostellar disk evolution, most notably in angular momentum transport, fragmentation, and the outbursts exemplified by FU Ori and EX Lupi systems. The outer regions of protostellar discs may also be coupled to magnetic fields, which could then modify the development of GI. To understand the basic elements of their interaction, we perform local 2D ideal and resistive MHD simulations with an imposed toroidal field. In the regime of moderate plasma beta, we find that the system supports a hot gravito-turbulent state, characterised by considerable magnetic energy and stress and a surprisingly large Toomre parameter $Q10$. This result has potential implications for disk structure, vertical thickness, ionisation, etc. Our simulations also reveal the existence of long-lived and dense `magnetic islands' or plasmoids. Lastly, we find that the presence of a magnetic field has little impact on the fragmentation criterion of the disk. Though our focus is on protostellar disks, some of our results may be relevant for the outer radii of AGN.

MNRAS submitted, revised after reviewer comments

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Cited by in corpus (14)

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• Global simulations of self-gravitating magnetized protoplanetary disks
• Magnetically elevated accretion disks in active galactic nuclei: broad emission line regions and associated star formation
• Gravito-turbulence and the excitation of small-scale parametric instability in astrophysical discs
• Magnetorotational instability and dynamo action in gravitoturbulent astrophysical discs
• Gravitoturbulent dynamos in astrophysical discs
• On the fragmentation boundary in magnetised self-gravitating discs
• Nonlinear outcome of gravitational instability in an irradiated protoplanetary disc
• Magnetic fields catalyze massive black hole formation and growth
• Spiral density waves and vertical circulation in protoplanetary discs
• Gravito-turbulence in irradiated protoplanetary discs
• Dissipative structures in magnetorotational turbulence
• Gravito-turbulence in local disk simulations with an adaptive moving mesh
• Gravito-turbulence and dynamo in poorly ionised protostellar discs. I. Zero-net-flux case