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The discovery of the first binary neutron star merger, GW170817, has spawned a plethora of global numerical relativity simulations. These simulations are often ideal (with dissipation determined by the grid) and/or axisymmetric (invoking ad…

High Energy Astrophysical Phenomena · Physics 2024-04-10 Loren E. Held , George Mamatsashvili , Martin E. Pessah

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

This paper reports on 3D numerical simulations of dynamics and thermodynamics in the diffuse ISM. Our models are local, account for sheared galactic rotation, magnetic fields, and realistic cooling, and resolve scales ~1-200 pc. This…

Astrophysics · Physics 2009-11-11 Robert A. Piontek , Eve C. Ostriker

The Global Magnetorotational Instability (MRI) is investigated for a configuration in which the rotation frequency changes only in a narrow transition region. If the vertical wavelength of the unstable mode is of the same order or smaller…

Instrumentation and Methods for Astrophysics · Physics 2011-02-11 J. Pino , S. M. Mahajan

The magnetorotational instability (MRI) is the most promising mechanism by which angular momentum is efficiently transported outwards in astrophysical discs. However, its application to protoplanetary discs remains problematic. These discs…

Earth and Planetary Astrophysics · Physics 2015-06-16 Matthew W. Kunz , Geoffroy Lesur

Simulations of astrophysical disks in the shearing box that are subject to the magnetorotational instability (MRI) show that activity appears to be reduced as the magnetic Prandtl number (Pm) is lowered. On the other hand, calculations for…

Solar and Stellar Astrophysics · Physics 2015-05-18 O. M. Umurhan

The magnetorotational instability (MRI) plays a crucial role in regulating the accretion efficiency in astrophysical accretion disks. In low-luminosity disks around black holes, such as Sgr A* and M87, Coulomb collisions are infrequent,…

High Energy Astrophysical Phenomena · Physics 2023-08-25 Astor Sandoval , Mario Riquelme , Anatoly Spitkovsky , Fabio Bacchini

Simulations of the magnetorotational instability (MRI) in a homogeneous shearing box have shown that the asymptotic strength of the magnetic field declines steeply with increasing resolution. Here I model the MRI driven dynamo as a large…

High Energy Astrophysical Phenomena · Physics 2011-02-11 Ethan T. Vishniac

The magneto-rotational instability (MRI) - which is due to an interplay between a sheared background and the magnetic field - is commonly considered a key ingredient for developing and sustaining turbulence in the outer envelope of binary…

High Energy Astrophysical Phenomena · Physics 2023-11-27 T. Celora , I. Hawke , N. Andersson , G. L. Comer

Many astrophysical disks, such as protoplanetary disks, are in a regime where non-ideal, plasma-specific magnetohydrodynamic (MHD) effects can significantly influence the behavior of the magnetorotational instability (MRI). The possibility…

Plasma Physics · Physics 2015-06-24 K. Flanagan , M. Clark , C. Collins , C. M. Cooper , I. V. Khalzov , J. Wallace , C. B. Forest

The interaction of differential rotation and toroidal fields that are current-free in the gap between two corotating axially unbounded cylinders is considered. It is shown that nonaxisymmetric perturbations are unstable if the rotation rate…

Solar and Stellar Astrophysics · Physics 2015-06-15 G. Ruediger , M. Gellert , M. Schultz , R. Hollerbach , F. Stefani

A new non-dissipative mechanism is proposed for the saturation of the axisymmetric magnetorotational (MRI) instability in thin Keplerian disks that are subject to an axial magnetic field. That mechanism relies on the energy transfer from…

Solar and Stellar Astrophysics · Physics 2015-06-11 Edward Liverts , Yuri Shtemler , Michael Mond , Orkan M. Umurhan , Dmitry V. Bisikalo

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

We present two-dimensional particle-in-cell (PIC) simulations of the fully kinetic collisionless magnetorotational instability (MRI) in weakly magnetized (high $\beta$) pair plasma. The central result of this numerical analysis is the…

High Energy Astrophysical Phenomena · Physics 2018-06-27 Giannandrea Inchingolo , Thomas Grismayer , Nuno F. Loureiro , Ricardo A. Fonseca , Luis O. Silva

We conduct a linear analysis of axisymmetric magnetorotational instability (MRI) in a magnetized cylindrical Taylor-Couette (TC) flow for its standard version (SMRI) with a purely axial background magnetic field and two further types --…

Fluid Dynamics · Physics 2022-06-07 A. Mishra , G. Mamatsashvili , F. Stefani

Magneto-rotational instability (MRI) and gravitational instability (GI) are the two principle routes to turbulent angular momentum transport in accretion disks. Protoplanetary disks may develop both. This paper aims to reinvigorate interest…

Earth and Planetary Astrophysics · Physics 2015-06-19 Min-Kai Lin

We re-analyze the physical conditions for Magneto-rotational Instability (MRI) within a steady axisymmetric stratified disk of plasma, in order to account for the so-called isorotation theory (the spatial profile of differential angular…

High Energy Astrophysical Phenomena · Physics 2017-04-26 Francesco Cianfrani , Giovanni Montani

The magnetorotational instability (MRI) is a promising mechanism to amplify the magnetic field in fast rotating protoneutron stars. The diffusion of neutrinos trapped in the PNS induces a transport of momentum, which can be modelled as a…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Jerome Guilet , Ewald Mueller , Hans-Thomas Janka

Layered accretion is one of the inevitable ingredients in protoplanetary disks when disk turbulence is excited by magnetorotational instabilities (MRIs). In the accretion, disk surfaces where MRIs fully operate have a high value of disk…

Earth and Planetary Astrophysics · Physics 2015-12-23 Yasuhiro Hasegawa , Taku Takeuchi

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