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We venture for the comparison between growth rates for magnetorotational instability (MRI) and hydrodynamics instability in the presence of an extra force in the local Keplerian accretion flow. The underlying model is described by the…

High Energy Astrophysical Phenomena · Physics 2022-05-27 Subham Ghosh , Banibrata Mukhopadhyay

The magnetorotational instability (MRI) is considered to be one of the most powerful sources of turbulence in hydrodynamically stable quasi-Keplerian flows, such as those governing accretion disk flows. Although the linear stability of…

Fluid Dynamics · Physics 2017-11-21 A. Guseva , R. Hollerbach , A. P. Willis , M. Avila

Using the anelastic approximation of linearised hydrodynamic equations, we investigate the development of axially symmetric small perturbations in thin Keplerian discs. The sixth-order dispersion equation is derived and numerically solved…

High Energy Astrophysical Phenomena · Physics 2015-07-02 N. Shakura , K. Postnov

The non-linear hydrodynamic stability of thin, compressible, Keplerian disks is studied on the large two-dimensional compressible scale, using a high-order accuracy spectral method. We show that purely hydrodynamic perturbations, while…

Astrophysics · Physics 2009-10-31 Patrick Godon , Mario Livio

We propose that the strength of angular momentum transport in accretion discs threaded by net vertical magnetic field is determined by a self-regulation mechanism: the magnetorotational instability (MRI) grows until its own turbulent…

High Energy Astrophysical Phenomena · Physics 2023-04-18 Mitchell C. Begelman , Philip J. Armitage

We consider the linear axisymmetric stability of a differentially rotating collisionless plasma in the presence of a weak magnetic field; we restrict our analysis to wavelengths much larger than the proton Larmor radius. This is the kinetic…

Astrophysics · Physics 2009-11-07 Eliot Quataert , William Dorland , Greg Hammett

The origin of hydrodynamic turbulence, and in particular of an anomalously enhanced angular momentum transport, in accretion disks is still an unsolved problem. This is especially important for cold disk systems which are practically…

Astrophysics · Physics 2008-11-26 Banibrata Mukhopadhyay

This work presents a linear analytical calculation on the stability and evolution of a compressible, viscous self-gravitating (SG) Keplerian disc with both horizontal thermal diffusion and a constant cooling timescale when an axisymmetric…

Solar and Stellar Astrophysics · Physics 2017-01-25 Riccardo Vanon , Gordon Ogilvie

We study local stability of the advection-dominated optically thick (slim) and optically thin discs with purely toroidal magnetic field and the radial viscous force using a linear perturbation analysis. Our dispersion relation indicates…

Astrophysics of Galaxies · Physics 2018-03-21 S. M. Ghoreyshi , Mohsen Shadmehri

We analyze an axisymmetric magnetohydrodynamics configuration, describing the morphology of a purely differentially rotating thin plasma disk, in which linear and non-linear perturbations are triggered associated with microscopic magnetic…

Solar and Stellar Astrophysics · Physics 2018-10-02 Giovanni Montani , Mariachiara Rizzo , Nakia Carlevaro

We study the development of coherent structures in local simulations of the magnetorotational instability in accretion discs in regimes of on-off intermittency. In a previous paper [Chian et al., Phys. Rev. Lett. 104, 254102 (2010)], we…

Solar and Stellar Astrophysics · Physics 2015-06-23 Rodrigo A. Miranda , Erico L. Rempel , Abraham C. -L. Chian

We revisit the modal analysis of small perturbations in Keplerian ideal gas flows leading to magneto-rotational instability (MRI) using the non-local approach. We consider the case of constant vertical background magnetic field, as well as…

High Energy Astrophysical Phenomena · Physics 2023-12-19 Nikolay Shakura , Konstantin Postnov , Dmitry Kolesnikov , Galina Lipunova

Origin of hydrodynamical instability and turbulence in the Keplerian accretion disc as well as similar laboratory shear flows, e.g. plane Couette flow, is a long standing puzzle. These flows are linearly stable. Here we explore the…

High Energy Astrophysical Phenomena · Physics 2020-07-01 Subham Ghosh , Banibrata Mukhopadhyay

Global three dimensional magnetohydrodynamic (MHD) simulations of turbulent accretion disks are presented which start from fully equilibrium initial conditions in which the magnetic forces are accounted for and the induction equation is…

High Energy Astrophysical Phenomena · Physics 2015-06-12 E. R. Parkin , G. V. Bicknell

A viscous instability in shearing laminar axisymmetric hydrodynamic flows around a gravitating center is described. In the linearized hydrodynamic equations written in the Boussinesq approximation with microscopic molecular transport…

High Energy Astrophysical Phenomena · Physics 2015-03-18 Nikolai Shakura , Konstantin Postnov

Magnetized disk winds and wind-driven accretion are an essential and intensively studied dispersion mechanism of protoplanetary disks. However, the stability of these mechanisms has yet to be adequately examined. This paper employs…

Earth and Planetary Astrophysics · Physics 2024-07-04 Lile Wang , Sheng Xu , Zhenyu Wang , Min Fang , Jeremy Goodman

We present the results of linear analysis and two-dimensional local magnetohydrodynamic (MHD) simulations of the Parker instability, including the effects of cosmic rays (CRs), in magnetized gas disks (galactic disks). As an unperturbed…

Astrophysics · Physics 2009-11-10 Takuhito Kuwabara , Kenji Nakamura , C. M. Ko

The stability of toroidal magnetic fields in rotating radiative stellar zones is studied for realistic values of both the Prandtl numbers. The two considered models for the magnetic geometry represent fields with odd and even symmetry with…

Solar and Stellar Astrophysics · Physics 2015-05-13 G. Ruediger , L. L. Kitchatinov

We present collapse simulations of strongly magnetised, turbulent molecular cloud cores with masses ranging from 2.6 to 1000 M_sun in order to study the influence of the initial conditions on the turbulence-induced disc formation mechanism…

Astrophysics of Galaxies · Physics 2015-06-15 D. Seifried , R. Banerjee , R. E. Pudritz , R. S. Klessen

We study the stability of poloidal magnetic fields anchored in a thin accretion disc. The two-dimensional hydrodynamics in the disc plane is followed by a grid-based numerical simulation including the vertically integrated magnetic forces.…

Astrophysics · Physics 2015-06-24 R. Stehle , H. C. Spruit