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Related papers: Magnetic instability in a sheared azimuthal flow

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The magnetorotational instability (MRI) in cylindrical Taylor-Couette flow with external helical magnetic field is simulated for infinite and finite aspect ratios. We solve the MHD equations in their small Prandtl number limit and confirm…

Astrophysics · Physics 2008-11-26 Jacek Szklarski , Günther Rüdiger

We study the stability properties of Rayleigh unstable flows both in the purely hydrodynamic and magnetohydrodynamic (MHD) regimes for two different values of the shear $q=2.1, 4.2$ ($q = - d\ln\Omega / d\ln r$) and compare it with the…

Solar and Stellar Astrophysics · Physics 2021-09-08 Farrukh Nauman , Eric G. Blackman

We have carried out high resolution MHD simulations of the nonlinear evolution of Kelvin-Helmholtz unstable flows in 2 1/2 dimensions. The modeled flows and fields were initially uniform except for a thin shear layer with a hyperbolic…

Astrophysics · Physics 2009-10-30 T. W. Jones , Joseph B. Gaalaas , Dongsu Ryu , Adam Frank

Modal instabilities in a flow through a channel at high Reynolds and Mach numbers are studied for three-dimensional perturbations. In addition to the Tollmien-Schlichting modes, there exist higher modes in a channel flow that do not have a…

Fluid Dynamics · Physics 2022-08-03 M. Deka , G. Tomar , V. Kumaran

Using a new numerical code we have carried out two-dimensional simulations of the nonlinear evolution of unstable sheared magnetohydrodynamic flows. We considered two cases: a strong magnetic field (Alfven Mach number, M_a = 2.5) and a weak…

Astrophysics · Physics 2009-10-28 Adam Frank , T. W. Jones , Dongsu Ryu , Joseph B. Gaalaas

We study the stability of density stratified flow between co-rotating vertical cylinders with rotation rates $\Omega_o < \Omega_i$ and radius ratio $r_i/r_o=0.877$, where subscripts $o$ and $i$ refer to the outer and inner cylinders. Just…

Fluid Dynamics · Physics 2016-04-12 Ruy Ibanez , Harry L. Swinney , Bruce Rodenborn

We study the three-dimensional incompressible magnetohydrodynamic (MHD) equations near Couette flow with a constant magnetic field perpendicular to the shear plane. Couette flow induces mixing and generates magnetic induction, while the…

Analysis of PDEs · Mathematics 2025-11-19 Niklas Knobel

First results of a new spherical Couette experiment are presented. The liquid metal flow in a spherical shell is exposed to a homogeneous axial magnetic field. For a Reynolds number Re=1000, we study the effect of increasing Hartmann number…

Fluid Dynamics · Physics 2017-07-24 C. Kasprzyk , E. Kaplan , M. Seilmayer , F. Stefani

A recent paper [R. Hollerbach and G. Rudiger, Phys. Rev. Lett. 95, 124501 (2005)] has shown that the threshold for the onset of the magnetorotational instability (MRI) in a Taylor-Couette flow is dramatically reduced if both axial and…

The linear stability of MHD Taylor-Couette flows in axially unbounded cylinders is considered, for magnetic Prandtl number unity. Magnetic fields varying from purely axial to purely azimuthal are imposed, with a general helical field…

Solar and Stellar Astrophysics · Physics 2015-05-14 G. Ruediger , M. Gellert , M. Schultz , R. Hollerbach

We study the stability of a type of stratified flows of the two dimensional inviscid incompressible MHD equations with velocity damping. The exponential stability for the perturbation near certain stratified flow is investigated in a…

Analysis of PDEs · Mathematics 2019-10-24 Yi Du , Wang Yang , Yi Zhou

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

Within the framework of shallow-water magnetohydrodynamics, we investigate the linear instability of horizontal shear flows, influenced by an aligned magnetic field and stratification. Various classical instability results, such as…

Fluid Dynamics · Physics 2016-01-15 Julian Mak , Stephen D. Griffiths , D. W. Hughes

This paper is a detailed report on a programme of simulations used to settle a long-standing issue in the dynamo theory and demonstrate that the fluctuation dynamo exists in the limit of large magnetic Reynolds number Rm>>1 and small…

In this study we consider the effect of a horizontal magnetic field on the Rayleigh-B\'enard convection in a finite liquid metal layer contained in a cuboid vessel (200 \times 200 \times 40 mm^3). Laboratory experiments are performed for…

Fluid Dynamics · Physics 2020-12-07 J. C. Yang , T. Vogt , S. Eckert

The nonaxisymmetric 'kink-type' Tayler instability (TI) of toroidal magnetic fields is studied for conducting incompressible fluids of uniform density between two infinitely long cylinders rotating around the same axis. It is shown that for…

Solar and Stellar Astrophysics · Physics 2015-05-13 G. Ruediger , M. Schultz

The questions of how strong magnetic fields can be stored in rotating stellar radiative zones without being subjected to pinch-type instabilities and how much radial mixing is produced if the fields are unstable are addressed. Linear…

Astrophysics · Physics 2009-11-13 L. L. Kitchatinov , G. Ruediger

Hollerbach and Rudiger have reported a new type of magnetorotational instability (MRI) in magnetized Taylor-Couette flow in the presence of combined axial and azimuthal magnetic fields. The salient advantage of this "helical'' MRI (HMRI) is…

Astrophysics · Physics 2008-11-26 Wei Liu , Jeremy Goodman , Isom Herron , Hantao Ji

In this paper we argue that differential rotation can possibly sustain hydrodynamic turbulence in the absence of magnetic field. We explain why the non-linearities of the hydrodynamic equations (i.e. turbulent diffusion) should not be…

Astrophysics · Physics 2009-11-10 D. T. Richard

We study the 3D magnetohydrodynamics (MHD) equations in an annular cylinder, perturbed around the explicit steady state given by the 3D Taylor-Couette velocity field and zero magnetic field. Combining a recent linear instability result for…

Analysis of PDEs · Mathematics 2025-10-15 Víctor Navarro-Fernández , David Villringer
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