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We have studied saturated, MRI-driven turbulence using three-dimensional, isothermal simulations with resolutions that extend from 64 to 192 zones in each direction. The simulations were performed with several higher order Godunov…

Astrophysics of Galaxies · Physics 2010-03-02 Dinshaw S. Balsara , Chad Meyer

The magnetorotational instability (MRI) is a fundamental mechanism determining the macroscopic dynamics of astrophysical accretion disks. In collisionless accretion flows around supermassive black holes, MRI-driven plasma turbulence…

High Energy Astrophysical Phenomena · Physics 2022-10-26 Fabio Bacchini , Lev Arzamasskiy , Vladimir Zhdankin , Gregory R. Werner , Mitchell C. Begelman , Dmitri A. Uzdensky

We present local numerical models of accretion disk turbulence driven by the magnetorotational instability with varying shear rate. The resulting turbulent stresses are compared with predictions of a closure model in which triple…

Astrophysics · Physics 2009-01-17 A. J. Liljeström , M. J. Korpi , P. J. Käpylä , A. Brandenburg , W. Lyra

The magnetorotational instability (MRI) plays an essential role in the formation of stars and black holes. By destabilizing hydrodynamically stable Keplerian flows, the MRI triggers turbulence and enables outward transport of angular…

The rate of magnetic field diffusion plays an essential role in several astrophysical plasma processes. It has been demonstrated that the omnipresent turbulence in astrophysical media induces fast magnetic reconnection, which consequently…

Solar and Stellar Astrophysics · Physics 2021-02-24 R. Santos-Lima , G. Guerrero , E. M. de Gouveia Dal Pino , A. Lazarian

We present results from two-dimensional numerical simulations of a supersonic turbulent flow in the plane of the galactic disk, incorporating shear, thresholded and discrete star formation (SF), self-gravity, rotation and magnetic fields. A…

Astrophysics · Physics 2009-10-28 T. Passot , E. Vazquez-Semadeni , A. Pouquet

Macroscopic gas motions are widespread throughout the solar atmosphere and shearing motions couple to the non--ideal effects, destabilising low frequency fluctuations in the medium. The origin of this non-ideal magnetohydrodynamic…

Solar and Stellar Astrophysics · Physics 2015-06-05 B. P. Pandey , Mark Wardle

Local simulations of the magnetorotational instability (MRI) in accretion disks can exhibit recurrent coherent structures called channel flows. The formation and destruction of these structures may play a role in the development and…

High Energy Astrophysical Phenomena · Physics 2010-11-02 Henrik N. Latter , Pierre Lesaffre , Steven A. Balbus

We investigate the characteristic properties of self-sustained MRI turbulence in low-ionized proto-planetary disks. We study the transition regime between active and dead-zone, performing 3D global non-ideal MHD simulations of stratified…

Earth and Planetary Astrophysics · Physics 2015-06-11 M. Flock , Th. Henning , H. Klahr

The magnetorotational instability (MRI) is an important process in sufficiently ionized accretion disks, as it can create turbulence that acts as an effective viscosity, mediating angular momentum transport. Due to its local nature, it is…

Earth and Planetary Astrophysics · Physics 2023-09-28 Oliver Zier , Volker Springel

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

In the interstellar medium the turbulence is believed to be forced mostly through supernova explosions. In a first approximation these flows can be written as a gradient of a potential being thus devoid of vorticity. There are several…

Astrophysics of Galaxies · Physics 2011-08-19 Fabio Del Sordo , Axel Brandenburg

The stability of a rotating fluid disk to the formation of spiral arms is studied in the tightwinding approximation in the linear regime. The dispersion relation for spirals that was derived by Bertin et al. is shown to contain a new,…

Astrophysics · Physics 2009-10-31 L. E. Montenegro , C. Yuan , B. G. Elmegreen

We present the results of local, vertically stratified, radiation magnetohydrodynamic shearing box simulations of magnetorotational instability (MRI) turbulence for a (hydrogen poor) composition applicable to accretion disks in AM CVn type…

Solar and Stellar Astrophysics · Physics 2018-04-25 Matthew S. B. Coleman , Omer Blaes , Shigenobu Hirose , Peter H. Hauschildt

We present a thorough numerical study on the MRI using the smoothed particle magnetohydrodynamics method (SPMHD) with the geometric density average force expression (GDSPH). We perform shearing box simulations with different initial setups…

Astrophysics of Galaxies · Physics 2022-03-14 R. Wissing , S. Shen , J. Wadsley , T. Quinn

The phenomenological Disc Instability Model has been successful in reproducing the observed light curves of dwarf nova outbursts by invoking an enhanced Shakura-Sunyaev $\alpha$ parameter $\sim0.1-0.2$ in outburst compared to a low value…

High Energy Astrophysical Phenomena · Physics 2016-08-17 M. S. B. Coleman , I. Kotko , O. Blaes , J. -P. Lasota , S. Hirose

The process of diffusive shock acceleration relies on the efficacy with which hydromagnetic waves can scatter charged particles in the precursor of a shock. The growth of self-generated waves is driven by both resonant and non-resonant…

Astrophysics · Physics 2009-11-13 B. Reville , S. O'Sullivan , P. Duffy , J. G. Kirk

The magnetorotational instability (MRI) is thought to be a powerful source of turbulence and momentum transport in astrophysical accretion discs, but obtaining observational evidence of its operation is challenging. Recently, laboratory…

Fluid Dynamics · Physics 2015-09-15 A. Guseva , A. P. Willis , R. Hollerbach , M. Avila

We present magnetohydrodynamic simulations aimed at studying the effect of the magnetic suppression of turbulence (generated through various instabilities during the formation of molecular clouds by converging) on the subsequent star…

Astrophysics of Galaxies · Physics 2017-12-08 Zamora-Avilés Manuel , Vázquez-Semadeni Enrique , Körtgen Bastian , Banerjee Robi , Hartmann Lee

Here, we present measurements of turbulent drag reduction in boundary layers at high friction Reynolds numbers in the range of $4500 \le Re_\tau \le 15000$. The efficacy of the approach, using streamwise travelling waves of spanwise wall…