2016/08/30 by A. Riols, G. I. Ogilvie, Gordon I. Ogilvie +4
Physics and Astronomy · #Accretion (finance) #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Star Formation Studies #Context (archaeology) #Instability #Magnetic field #Magnetohydrodynamics #Magnetorotational instability #Mechanics #Physics #Stellar, planetary, and galactic studies #Turbulence #astro-ph.HE
paper · pdf · doi:10.1093/mnras/stw2196
19 pages, 16 figures, accepted in MNRAS (August, 30th 2016)
arxiv created 2016/08/30 · openalex publication_date 2016/09/01 · arxiv updated 2016/09/07 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Jets, from the protostellar to the AGN context, have been extensively studied but their connection to the turbulent dynamics of the underlying accretion disc is poorly understood. Following a similar approach to Lesur, Fereira & Ogilvie, we examine the role of the magnetorotational instability (MRI) in the production and acceleration of outflows from discs. Via a suite of 1D shearing-box simulations of stratified discs, we show that magnetocentrifugal winds exhibit cyclic activity with a period of 10–20 Ω−1, a few times the orbital period. The cycle seems to be more vigorous for strong vertical field; it is robust to the variation of relevant parameters and independent of numerical details. The convergence of these solutions (in particular the mass-loss rate) with vertical box size is also studied. By considering a sequence of magnetohydrostatic equilibria and their stability, the periodic activity may be understood as the succession of the following phases: (a) a dominant MRI channel mode, (b) strong magnetic field generation, (c) consequent wind launching, and ultimately (d) vertical expulsion of the excess magnetic field by the expanding and accelerating gas associated with the wind. We discuss potential connections between this behaviour and observed time-variability in disc–jet systems.