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Related papers: Localized magnetorotational instability and its ro…

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The Accretion-Ejection Instability (AEI) is explored numerically using a global 2d model of the inner region of a magnetised accretion disk. The disk is initially currentless but threaded by an external vertical magnetic field created by…

Astrophysics · Physics 2007-05-23 Stuart Caunt , Michel Tagger

We examine the small-scale dynamics of black hole accretion disks in which radiation pressure exceeds gas pressure. Local patches of disk are modeled by numerically integrating the equations of radiation MHD in the flux-limited diffusion…

Astrophysics · Physics 2008-11-26 N. J. Turner , J. M. Stone , J. H. Krolik , T. Sano

We present the results of axisymmetric simulations of MRI-driven accretion onto a rapidly rotating, magnetized star accreting in the propeller regime. The stellar magnetosphere corotates with the star, forming a centrifugal barrier at the…

Solar and Stellar Astrophysics · Physics 2015-06-15 Patrick S Lii , Marina M. Romanova , Galina V. Ustyugova , Alexander V. Koldoba , Richard V. E. Lovelace

We analyze the linear stability of an axially symmetric ideal plasma disk, embedded in a magnetic field and endowed with a differential rotation. This study is performed by adopting the magnetic flux function as the fundamental dynamical…

High Energy Astrophysical Phenomena · Physics 2016-07-26 G. Montani , F. Cianfrani , D. Pugliese

Previously we demonstrated that the magnetorotational instability (MRI) grows vigorously in eccentric disks, much as it does in circular disks, and we investigated the nonlinear development of the eccentric MRI without vertical gravity.…

High Energy Astrophysical Phenomena · Physics 2025-05-07 Chi-Ho Chan , Tsvi Piran , Julian H. Krolik

We investigate the stability of differentially rotating proto-neutron stars (PNSs) with a toroidal magnetic field. Stability criteria for nonaxisymmetric MHD instabilities are derived using a local linear analysis. PNSs are expected to have…

Astrophysics · Physics 2009-11-13 Youhei Masada , Takayoshi Sano , Hideaki Takabe

The formation of binary stars is highly influenced by magnetic fields, which play a crucial role in transporting angular momentum. We conducted three-dimensional numerical simulations of binary star accretion via a circumbinary disk, taking…

Solar and Stellar Astrophysics · Physics 2024-02-06 Tomoaki Matsumoto

We aim to illustrate the role of hot protons in enhancing the magnetorotational instability (MRI) via the ``hybrid'' viscosity, which is due to the redirection of protons interacting with static magnetic field perturbations, and to…

Astrophysics · Physics 2009-11-13 Prasad Subramanian , Peter A. Becker , Menas Kafatos

We investigate the global stability of a differentially rotating fluid shell threaded by vertical and azimuthal magnetic fields to linear, axisymmetric perturbations. This system, which models a thick accretion disk in the vicinity of its…

Astrophysics · Physics 2009-10-28 Charles Curry , Ralph E. Pudritz

The magneto-rotational instability (MRI) is widely believed to play a central role in generating large-scale, poloidal magnetic fields during binary neutron star mergers. However, the few simulations that begin with a weak seed magnetic…

High Energy Astrophysical Phenomena · Physics 2026-01-28 T. Celora , C. Palenzuela , D. Viganò , R. Aguilera-Miret

The magnetorotational instability (MRI) plays an essential role in the formation of stars and black holes. By destabilizing hydrodynamically stable Keplerian flows, the MRI triggers turbulence and enables outward transport of angular…

We study the effect of large-scale magnetic fields on the non-axisymmetric Rossby wave instability (RWI) in accretion discs. The instability develops around a density bump, which is likely present in the transition region between the active…

Earth and Planetary Astrophysics · Physics 2015-06-12 Cong Yu , Dong Lai

Accretion disks in Active Galactic Nuclei (AGN) are predicted to become gravitationally unstable substantially interior to the black hole's sphere of influence, at radii where the disk is simultaneously unstable to the magnetorotational…

High Energy Astrophysical Phenomena · Physics 2025-07-30 Tsun Hin Navin Tsung , Mitchell C. Begelman , Philip J. Armitage , Yan-Fei Jiang , Hannalore J. Gerling-Dunsmore

Asteroseismology has revealed small core-to-surface rotation contrasts in stars in the whole HR diagram. This is the signature of strong transport of angular momentum (AM) in stellar interiors. One of the plausible candidates to efficiently…

Solar and Stellar Astrophysics · Physics 2022-05-24 Hachem Dhouib , Stéphane Mathis , Lisa Bugnet , Timothy Van Reeth , Conny Aerts

We use a global magnetohydrodynamic simulation of a geometrically thin accretion disk to investigate the locality and detailed structure of turbulence driven by the magnetorotational instability (MRI). The model disk has an aspect ratio $H…

High Energy Astrophysical Phenomena · Physics 2015-05-28 Kris Beckwith , Philip J. Armitage , Jacob B. Simon

We investigate the possibility of the growth of magnetorotational instability (MRI) in disks around Class 0 protostars. We construct a disk model and calculate the chemical reactions of neutral and charged atoms, molecules and dust grains…

Solar and Stellar Astrophysics · Physics 2021-05-12 Yoshihiro Kawasaki , Shunta Koga , Masahiro N. Machida

Global axisymmetric stability of viscous, resistive, magnetized Couette flow is re-examined, with the emphasis on flows that would be hydrodynamically stable according to Rayleigh's criterion: opposing gradients of angular velocity and…

Astrophysics · Physics 2009-11-06 Jeremy Goodman , Hantao Ji

The linear dispersion relation for the magnetorotational instability (MRI) is derived including finite Larmor radius (FLR) effects. In particular, the Braginskii form of the ion gyroviscosity, which represents the first-order FLR…

Astrophysics · Physics 2011-02-11 Nathaniel M. Ferraro

The effects of ambipolar diffusion on the linear stability of weakly ionised accretion discs are examined. Earlier work on this topic has focused on axial magnetic fields and perturbation wavenumbers. We consider here more general field and…

Astrophysics · Physics 2009-11-10 Matthew W. Kunz , Steven A. Balbus

During the last decade it has become evident that the magnetorotational instability is at the heart of the enhanced angular momentum transport in weakly magnetized accretion disks around neutron stars and black holes. In this paper, we…

Astrophysics · Physics 2009-11-10 Martin E. Pessah , Dimitrios Psaltis