3D MHD simulation of a pulsationally driven MRI decretion disc

نویسندگان

چکیده

ABSTRACT We explore the pulsationally driven orbital mass ejection mechanism for Be star disc formation using isothermal, 3D magnetohydrodynamic (MHD) and hydrodynamic simulations. Non-radial pulsations are added to a rotating at 95 per cent of critical as an inner boundary condition that feeds gas into domain. In MHD, initial magnetic field within is weak. The hydrodynamics simulation has limited angular momentum transport, resulting in repeating cycles accumulation rotationally supported small radii followed by fall-back on star. MHD simulation, conversely, efficient (Maxwell αM ∼ 0.04) transport provided both turbulent coherent fields: slowly decreting midplane magnetorotational instability supersonic wind surface global torques. angle time-averaged properties near agree reasonably well with 1D viscous decretion model modified $\tilde{\alpha }=0.5$, which transitions from subsonic thin spherical point. models, however, cannot capture multiphase decretion/angular structure seen our Our results demonstrate that, least under certain conditions, non-radial rapidly rotating, weakly magnetised can drive Keplerian basic paradigm, albeit coupled laminar away midplane. Future modelling discs should consider possible existence such wind.

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ژورنال

عنوان ژورنال: Monthly Notices of the Royal Astronomical Society

سال: 2021

ISSN: ['0035-8711', '1365-8711', '1365-2966']

DOI: https://doi.org/10.1093/mnras/stab2880