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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

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

Though usually treated in isolation, the magnetorotational and gravitational instabilities (MRI and GI) may coincide at certain radii and evolutionary stages of protoplanetary discs and active galactic nuclei. Their mutual interactions…

High Energy Astrophysical Phenomena · Physics 2017-12-27 A. Riols , H. Latter

We study the magneto-rotational instability (MRI) driven dynamo in a geometrically thin disc ($H/R\ll 1$) using stratified zero net flux (ZNF) shearing box simulations. We find that mean fields and EMFs oscillate with a primary frequency…

High Energy Astrophysical Phenomena · Physics 2024-07-22 Prasun Dhang , Abhijit Bendre , Kandaswamy Subramanian

It is demonstrated that the azimuthal magnetorotational instability (AMRI) also works with radially increasing rotation rates contrary to the standard magnetorotational instability for axial fields which requires negative shear. The…

Fluid Dynamics · Physics 2017-12-14 Guenther Rüdiger , Manfred Schultz , Marcus Gellert , Frank Stefani

Two different computational approaches to the magnetorotational instability (MRI) are pursued: the shearing box approach which is suited for local simulations and the embedding box approach whereby a Taylor Couette flow is embedded in a box…

Astrophysics · Physics 2009-11-10 A. Brandenburg , B. Dintrans , N. E. L. Haugen

The merger of two neutron stars may give birth to a long-lived hypermassive neutron star. If it harbours a strong magnetic field of magnetar strength, its spin-down could explain several features of short gamma-ray burst afterglows. The…

High Energy Astrophysical Phenomena · Physics 2017-08-23 Jerome Guilet , Andreas Bauswein , Oliver Just , Hans-Thomas Janka

We investigate shear and buoyancy instabilities in radially stratified, magnetized, cylindrical flows, for application to magnetocentrifugally driven winds and to magnetized accretion disks. We identify and study nine principal types of…

Astrophysics · Physics 2009-10-31 Woong-Tae Kim , Eve C. Ostriker

Magnetorotational instability (MRI) is one of the most important and most common instabilities in astrophysics, it is widely accepted that it serves as a source of turbulent viscosity in accretion disks -- the most energy efficient objects…

Astrophysics · Physics 2007-05-23 J. Szklarski

We investigate numerically the Princeton magneto-rotational instability (MRI) experiment and the effect of conducting axial boundaries or endcaps. MRI is identified and found to reach a much higher saturation than for insulating endcaps.…

Fluid Dynamics · Physics 2017-01-04 Xing Wei , Hantao Ji , Jeremy Goodman , Fatima Ebrahimi , Erik Gilson , Frank Jenko , Karl Lackner

Convection has been discussed in the field of accretion discs for several decades, both as a means of angular momentum transport and also because of its role in controlling discs' vertical structure via heat transport. If the gas is…

Solar and Stellar Astrophysics · Physics 2021-04-21 Loren E. Held , Henrik N. Latter

The initial magnetic field of previous magnetorotational instability (MRI) simulations has always included a significant system-scale component, even if stochastic. However, it is of conceptual and practical interest to assess whether the…

High Energy Astrophysical Phenomena · Physics 2017-10-13 Pallavi Bhat , Fatima Ebrahimi , Eric G. Blackman , Kandaswamy Subramanian

Long-period cyclic reversals of the large-scale magnetic field are a prominent feature of the dynamo associated with the magnetorotational instability (MRI) in accretion disks, but their physical origin remains unclear. We develop a…

High Energy Astrophysical Phenomena · Physics 2026-05-11 Uddipan Banik , Amitava Bhattacharjee , James M. Stone

The magnetorotational instability (MRI) is believed to be responsible for most of the angular momentum transport in accretion discs. However, molecular dissipation processes may drastically change the efficiency of MRI turbulence in…

Earth and Planetary Astrophysics · Physics 2015-05-20 Geoffroy Lesur , Pierre-Yves Longaretti

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 study the influence of numerical methods and grid resolution on the termination of the magnetorotational instability (MRI) by means of parasitic instabilities in three-dimensional shearing-disc simulations reproducing typical conditions…

Solar and Stellar Astrophysics · Physics 2016-06-22 T. Rembiasz , M. Obergaulinger , P. Cerdá-Durán , M. Á. Aloy , E. Müller

This work concentrates on the effect of an irrotational forcing on a magnetized flow in the presence of rotation, baroclinicity, shear, or a combination of them. By including magnetic field in the model we can evaluate the occurrence of…

Astrophysics of Galaxies · Physics 2023-09-08 Albert Elias-López , Fabio Del Sordo , Daniele Viganò

We examine global incompressible axisymmetric perturbations of a differentially rotating MHD plasma with radial density gradients. It is shown that the standard magnetorotational instability, (MRI) criterion drawn from the local dispersion…

Astrophysics · Physics 2009-11-13 Jesse Pino , S. M. Mahajan

Stability properties of magnetic-field configurations containing the toroidal and axial field are considered. The stability is treated by making use of linear analysis. It is shown that the conditions required for the onset of instability…

Astrophysics · Physics 2009-11-13 Alfio Bonanno , Vadim Urpin

The origin of large-scale and coherent magnetic fields in astrophysical discs is an important and long standing problem. Researchers commonly appeal to a turbulent dynamo, sustained by the magneto-rotational instability (MRI), to supply the…

High Energy Astrophysical Phenomena · Physics 2018-10-24 A. Riols , H. Latter