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We study the two-dimensional, time-dependent MHD of radiation-driven winds from luminous accretion disks initially threaded by a purely axial magnetic field. The radiation force is mediated primarily by spectral lines. We use ideal MHD to…

Astrophysics · Physics 2009-11-07 D. Proga

The effect of large magnetic Prandtl number $\text{Pm}$ (the ratio of viscosity to resistivity) on the turbulent transport and energetics of the magnetorotational instability (MRI) is poorly understood, despite the realization of this…

High Energy Astrophysical Phenomena · Physics 2022-09-28 Loren E. Held , George Mamatsashvili

Radiatively inefficient accretion flows onto black holes are unstable due to both an outwardly decreasing entropy (`convection') and an outwardly decreasing rotation rate (the `magnetorotational instability'; MRI). Using a linear…

Astrophysics · Physics 2009-11-07 Ramesh Narayan , Eliot Quataert , Igor V. Igumenshchev , Marek A. Abramowicz

We calculate growth rates for nonaxisymmetric instabilities including the magnetorotational instability (MRI) throughout the Sun. We first derive a dispersion relation for nonaxisymmetric instability including the effects of shear,…

Solar and Stellar Astrophysics · Physics 2015-06-22 Daniel Kagan , J. Craig Wheeler

The turbulence driven by gravitational instabilities (GIs) can amplify magnetic fields in massive gaseous disks. This GI dynamo may appear in young circumstellar disks, whose weak ionization challenges other amplification routes, as well as…

Solar and Stellar Astrophysics · Physics 2022-07-27 William Béthune , Henrik Latter

We study local magnetohydrodynamical (MHD) instabilities of differential rotation in magnetised, stably-stratified regions of stars and planets using a Cartesian Boussinesq model. We consider arbitrary latitudes and general shears (with…

Solar and Stellar Astrophysics · Physics 2024-10-10 Robert W. Dymott , Adrian J. Barker , Chris A. Jones , Steven M. Tobias

The study of the magnetic field in stellar radiation zones is an important topic in modern astrophysics because the magnetic field can play an important role in several transport phenomena such as mixing and angular momentum transport. We…

Solar and Stellar Astrophysics · Physics 2015-06-15 Alfio Bonanno , Vadim Urpin

The saturation level of the magneto-rotational instability (MRI) in a strongly radiation dominated accretion disk is studied using a new Godunov radiation MHD code in the unstratified shearing box approximation. Since vertical gravity is…

High Energy Astrophysical Phenomena · Physics 2013-04-09 Yan-Fei Jiang , James M. Stone , Shane W. Davis

We analyze the morphology of the Magneto-rotational Instability (MRI) for a stratified viscous plasma disk configuration in differential rotation, taking into account the so-called corotation theorem for the background profile. In order to…

Plasma Physics · Physics 2017-04-26 Nakia Carlevaro , Giovanni Montani , Fabrizio Renzi

We describe an instability of viscoelastic Couette-Taylor flow that is directly analogous to the magnetorotational instability (MRI) in astrophysical magnetohydrodynamics, with polymer molecules playing the role of magnetic field lines. By…

Astrophysics · Physics 2009-06-23 Gordon I. Ogilvie , Adrian T. Potter

Turbulence and dynamo induced by the magnetorotational instability (MRI) are analyzed using quasi-linear statistical simulation methods. It is found that homogenous turbulence is unstable to a large scale dynamo instability, which saturates…

High Energy Astrophysical Phenomena · Physics 2015-06-01 Jonathan Squire , Amitava Bhattacharjee

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

We investigate the effect of shear viscosity and Ohmic resistivity on the magnetorotational instability (MRI) in vertically stratified accretion disks through a series of local simulations with the Athena code. First, we use a series of…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Jacob B. Simon , John F. Hawley , Kris Beckwith

We investigated the impacts of magnetorotational instability (MRI) on the dynamics of weakly magnetized, rapidly rotating core-collapse by conducting high resolution MHD simulations in axisymmetry with simplified neutrino transfer. We found…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Hidetomo Sawai , Shoichi Yamada

We use the mean-field dynamo equations to show that an incoherent alpha effect in mirror-symmetric turbulence in a shearing flow can generate a large scale, coherent magnetic field. We illustrate this effect with simulations of a few simple…

Astrophysics · Physics 2015-06-24 Ethan T. Vishniac , Axel Brandenburg

Outward transport of angular momentum, as well as viscous and thermal stability, are the necessary criteria for the formation of accretion disc and to radiate steadily. Turbulent motions originating from magneto-rotational instability or…

High Energy Astrophysical Phenomena · Physics 2022-05-18 Sudeb Ranjan Datta , Tushar Mondal , Banibrata Mukhopadhyay

The stability of charged particle motion in a uniform magnetic field with an added spatially uniform transverse rotating magnetic field (RMF) is studied analytically. It is found that the stability diagram of a single-particle's orbit…

Plasma Physics · Physics 2024-12-13 E. Palmerduca , H. Qin , S. A. Cohen

We present a scaling law that predicts the values of the stresses obtained in numerical simulations of saturated MRI-driven turbulence in non-stratified shearing boxes. It relates the turbulent stresses to the strength of the vertical…

Astrophysics · Physics 2009-11-13 Martin E. Pessah , Chi-kwan Chan , Dimitrios Psaltis

The magnetorotational instability (MRI) drives magnetized turbulence in sufficiently ionized regions of protoplanetary disks, leading to mass accretion. The dissipation of the potential energy associated with this accretion determines the…

Earth and Planetary Astrophysics · Physics 2015-06-22 Colin P. McNally , Alexander Hubbard , Chao-Chin Yang , Mordecai-Mark Mac Low

We investigate the global nonaxisymmetric Rossby vortex instability in a differentially rotating, compressible magnetized accretion disk with radial density structures. Equilibrium magnetic fields are assumed to have only the toroidal…

Solar and Stellar Astrophysics · Physics 2009-08-11 Cong Yu , Hui Li
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