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The Rossby wave instability (RWI) is the fundamental non-axisymmetric radial shear instability in disks. The RWI can facilitate disk accretion, set the shape of planetary gaps and produce large vortices. It arises from density and/or…

Earth and Planetary Astrophysics · Physics 2024-07-18 Eonho Chang , Andrew N. Youdin

A linear but global numerical model for the magnetorotational instability (MRI) in disk geometry is considered to estimate the instability parameters for galaxies. Similarity rules suggested by a local analysis are applied to reveal a…

Astrophysics · Physics 2016-08-16 L. L. Kitchatinov , G. Rüdiger

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

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

The magnetorotational instability(MRI) in the Kerr spacetime is studied on a 3+1 viewpoint. The Maxwell's equations are expressed in a circularly orbiting observer's frame that co-rotates with matter in Keplerian orbits. There exist large…

Astrophysics · Physics 2009-11-10 M. Yokosawa , T. Inui

It has been shown in a previous work that torsional Alfv\'en waves can drive turbulence in nonuniform coronal loops with a purely axial magnetic field. Here we explore the role of the magnetic twist. We model a coronal loop as a…

Solar and Stellar Astrophysics · Physics 2022-09-21 Sergio Díaz-Suárez , Roberto Soler

By constructing a global model based on 3D local magnetohydrodynamical (MHD) simulations, we show that the disk wind driven by magnetorotational instability (MRI) plays a significant role in the dispersal of the gas component of…

Solar and Stellar Astrophysics · Physics 2011-02-11 Takeru K. Suzuki , Takayuki Muto , Shu-ichiro Inutsuka

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

Dynamics of linear perturbations in a differentially rotating accretion disk with non-homogeneous vertical structure is investigated. It has been found that turbulent viscosity results in instability of both pinching oscillations, and…

Astrophysics · Physics 2007-05-23 A. V. Khoperskov , S. S. Khrapov

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

We derive expressions for the local ideal magnetohydrodynamic (MHD) equations for a warped astrophysical disc using a warped shearing box formalism. A perturbation expansion of these equations to first order in the warping amplitude leads…

Solar and Stellar Astrophysics · Physics 2018-04-04 Joseph B. Paris , Gordon I. Ogilvie

Disk accretion onto a weakly magnetized central object, e.g. a star, is inevitably accompanied by the formation of a boundary layer near the surface, in which matter slows down from the highly supersonic orbital velocity of the disk to the…

Solar and Stellar Astrophysics · Physics 2015-06-05 Mikhail A. Belyaev , Roman R. Rafikov , James M. Stone

The saturation mechanism of Magneto-Rotational Instability (MRI) is examined through analytical quasilinear theory and through nonlinear computation of a single mode in a rotating disk. We find that large-scale magnetic field is generated…

High Energy Astrophysical Phenomena · Physics 2011-02-11 F. Ebrahimi , S. C. Prager , D. D. Schnack

To better understand the interaction of global tearing modes and microturbulence in the Madison Symmetric Torus (MST) reversed-field pinch (RFP), the global gyrokinetic code \textsc{Gene} is modified to describe global tearing mode…

Plasma Physics · Physics 2023-10-16 T. Jitsuk , A. Di Siena , M. J. Pueschel , P. W. Terry , F. Widmer , E. Poli , J. S. Sarff

We report on the first global three-dimensional (3D) MHD simulations of disk accretion onto a rotating magnetized star through the Rayleigh-Taylor instability. The star has a dipole field misaligned relative to the rotation axis by a small…

Astrophysics · Physics 2018-01-17 Marina M. Romanova , Akshay K. Kulkarni , Richard V. E. Lovelace

The spectral stability of liquid metal differentially rotating in transverse magnetic field is studied numerically by solving the eigenvalue problem with rigid-wall boundary conditions. The equilibrium velocity profile used in calculations…

Astrophysics · Physics 2012-11-09 I. V. Khalzov , A. I. Smolyakov , V. I. Ilgisonis

The magnetorotational instability (MRI) has been proposed as the method of angular momentum transport that enables accretion in astrophysical discs. However, for weakly-ionized discs, such as protoplanetary discs, it remains unclear whether…

Instrumentation and Methods for Astrophysics · Physics 2023-09-15 Amy Secunda , Peter Donnel , Hantao Ji , Jeremy Goodman

We examine the linear stability analysis of a hot, dilute and differentially rotating plasma by considering anisotropic transport effects. In the dilute plasmas, the ion Larmor radius is small compared with its collisional mean free path.…

Astrophysics of Galaxies · Physics 2012-10-31 Ebru Devlen

(Abridged) We report results of three dimensional MHD simulations of global accretion disks threaded with weak vertical magnetic fields. We perform the simulations in the spherical coordinates with different temperature profiles and…

Earth and Planetary Astrophysics · Physics 2015-06-17 Takeru K. Suzuki , Shu-ichiro Inutsuka

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