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We study the local stability of stratified, differentially-rotating fluids to axisymmetric perturbations in the presence of a weak magnetic field and of finite resistivity, viscosity and heat conductivity. This is a generalization of the…

Astrophysics · Physics 2009-11-10 Kristen Menou , Steven A. Balbus , Henk C. Spruit

When magnetohydrodynamic turbulence evolves in the presence of a large-scale mean magnetic field, an anisotropy develops relative to that preferred direction. The well-known tendency is to develop stronger gradients perpendicular to the…

Plasma Physics · Physics 2020-07-15 Rohit Chhiber , William H. Matthaeus , Sean Oughton , Tulasi N. Parashar

It has been suggested that quasi-periodic oscillations of accreting X-ray sources may relate to the modes named in the title. We consider non-axisymmetric linear perturbations to an isentropic, isothermal, unmagnetized thin accretion disk.…

Astrophysics · Physics 2009-11-07 Li-Xin Li , Jeremy Goodman , Ramesh Narayan

Turbulent Richtmyer--Meshkov instability (RMI) is investigated through a series of high resolution three dimensional smulations of two initial conditions with eight independent codes. The simulations are initialised with a narrowband…

We conduct a linear stability calculation of an ideal Keplerian flow on which a sinusoidal zonal flow is imposed. The analysis uses the shearing sheet model and is carried out both in isothermal and adiabatic conditions, with and without…

Solar and Stellar Astrophysics · Physics 2017-09-06 R. Vanon , G. I. Ogilvie

We study the saturation near threshold of the axisymmetric magnetorotational instability (MRI) of a viscous, resistive, incompressible fluid in a thin-gap Taylor-Couette configuration. A vertical magnetic field, Keplerian shear and no-slip,…

Astrophysics · Physics 2009-11-13 O. M. Umurhan , O. Regev , K. Menou

We discuss non-self-gravitating hydrodynamic disks in the thin disk limit. These systems are stable according to the Rayleigh criterion, and yet there is some evidence that the dissipative and transport processes in these disks are…

Astrophysics · Physics 2007-05-23 Peter Todd Williams

The effects of velocity shear on the unstable modes driven by the effective gravity (Rayleigh-Taylor and interchange) and resistive drift wave instabilities for inhomogeneous equilibrium fluid/plasma density are analyzed for the localized…

Plasma Physics · Physics 2020-02-19 Yanzeng Zhang , S. I. Krasheninnikov , A. I. Smolyakov

The local properties of turbulence driven by the magnetorotational instability (MRI) in rotating, shearing flows are studied in the framework of a shearing-box model. Based on numerical simulations, we propose that the MRI-driven turbulence…

Solar and Stellar Astrophysics · Physics 2015-12-14 Justin Walker , Geoffroy Lesur , Stanislav Boldyrev

Linear stability of inviscid, parallel, and stably stratified shear flow is studied under the assumption of smooth strictly monotonic profiles of shear flow and density, so that the local Richardson number is positive everywhere. The…

Fluid Dynamics · Physics 2016-05-04 Makoto Hirota , Philip J. Morrison

We study linear transient dynamics in a thin Keplerian disc employing a method based on variational formulation of optimisation problem. It is shown that in a shearing sheet approximation due to a prominent excitation of density waves by…

High Energy Astrophysical Phenomena · Physics 2015-06-19 V. V. Zhuravlev , D. N. Razdoburdin

Turbulence in a conducting plasma can amplify seed magnetic fields in what is known as the turbulent, or small-scale, dynamo. The associated growth rate and emergent magnetic-field geometry depend sensitively on the material properties of…

High Energy Astrophysical Phenomena · Physics 2022-10-17 Alisa K. Galishnikova , Matthew W. Kunz , Alexander A. Schekochihin

We develop a new scaling theory for the resistive tearing mode instability of a current sheet with a strong shear flow across the layer. The growth rate decreases with increasing flow shear and is completely stabilized as the shear flow…

Plasma Physics · Physics 2026-01-14 Alfred Mallet , Stefan Eriksson , Marc Swisdak , James Juno

We report the first direct evidence for the axisymmetric standard magnetorotational instability (SMRI) from a combined experimental and numerical study of a magnetized liquid-metal shear flow in a Taylor-Couette cell with independently…

Instrumentation and Methods for Astrophysics · Physics 2022-09-20 Yin Wang , Erik P. Gilson , Fatima Ebrahimi , Jeremy Goodman , Hantao Ji

An analytical method within the frame of linear stability theory is presented for the normal field instability in magnetic fluids. It allows to calculate the maximal growth rate and the corresponding wave number for any combination of…

patt-sol · Physics 2009-10-31 Adrian Lange , Bert Reimann , Reinhard Richter

The linear stability of a rotating, stratified, inviscid horizontal plane Couette flow in a channel is studied in the limit of strong rotation and stratification. An energy argument is used to show that unstable perturbations must have…

Fluid Dynamics · Physics 2009-11-13 J Vanneste , I Yavneh

The magnetorotational instability (MRI) is the leading candidate for driving turbulence, angular momentum transport, and accretion in astrophysical disks. I consider the linear theory of the MRI in a thin, equatorial disk in the Kerr…

Astrophysics · Physics 2009-11-10 Charles F. Gammie

We employ a variety of numerical simulations in the local shearing box system to investigate in greater depth the local hydrodynamic stability of Keplerian differential rotation. In particular we explore the relationship of Keplerian shear…

Astrophysics · Physics 2009-10-31 John F. Hawley , Steven A. Balbus , Wayne F. Winters

We investigate the evolution of hydromagnetic perturbations in a small section of accretion disks. It is known that molecular viscosity is negligible in accretion disks. Hence, it has been argued that Magnetorotational Instability (MRI) is…

High Energy Astrophysical Phenomena · Physics 2016-03-02 Sujit K. Nath , Banibrata Mukhopadhyay

This paper demonstrates an equivalence between rotating magnetised shear flows and a stressed elastic beam. This results from finding the same form of dynamical equations after an asymptotic reduction of the axis-symmetric magnetorotational…

Solar and Stellar Astrophysics · Physics 2018-04-30 Geoff Vasil