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The interaction between settling of dust grains and magnetorotational instability (MRI) turbulence in protoplanetary disks is analyzed. We use a reduced system of coupled ordinary differential equations to represent the interaction between…

Earth and Planetary Astrophysics · Physics 2015-06-04 Emmanuel Jacquet , Steven Balbus

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

We examine the properties of strongly magnetized accretion discs in a global framework, with particular focus on the evolution of magnetohydrodynamic instabilities such as the magnetorotational instability (MRI). Work by Pessah and Psaltis…

High Energy Astrophysical Phenomena · Physics 2017-11-13 Upasana Das , Mitchell C. Begelman , Geoffroy Lesur

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

The magnetorotational instability (MRI) is a crucial mechanism of angular momentum transport in a variety of astrophysical accretion disks. In systems accreting at well below the Eddington rate, such as the central black hole in the Milky…

High Energy Astrophysical Phenomena · Physics 2015-06-04 Mario A. Riquelme , Eliot Quataert , Prateek Sharma , Anatoly Spitkovsky

Spatially resolved observations of molecular line emission have the potential to yield unique constraints on the nature of turbulence within protoplanetary disks. Using a combination of local non-ideal magnetohydrodynamic simulations and…

Solar and Stellar Astrophysics · Physics 2015-08-19 Jacob B. Simon , A. Meredith Hughes , Kevin M. Flaherty , Xue-Ning Bai , Philip J. Armitage

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

We present the results of axisymmetric simulations of MRI-driven accretion onto a rapidly rotating, magnetized star accreting in the propeller regime. The stellar magnetosphere corotates with the star, forming a centrifugal barrier at the…

Solar and Stellar Astrophysics · Physics 2015-06-15 Patrick S Lii , Marina M. Romanova , Galina V. Ustyugova , Alexander V. Koldoba , Richard V. E. Lovelace

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

We investigate stochastic particle acceleration in accretion flows. It is believed that the magnetorotational instability (MRI) generates turbulence inside accretion flows and that cosmic rays (CRs) are accelerated by the turbulence. We…

High Energy Astrophysical Phenomena · Physics 2016-05-25 Shigeo S. Kimura , Kenji Toma , Takeru K. Suzuki , Shu-ichiro Inutsuka

We show that an MHD-instability driven dynamo (IDD) operating in a hot accretion disk is capable of generating energetically adequate magnetic flux deposition rates above and below a mildly advective accretion disk structure. The dynamo is…

Astrophysics · Physics 2009-10-31 Rafael Angel Araya-Gochez

It is widely believed that in active galactic nuclei (AGNs) a supermassive black hole with an accretion disk is surrounded by an optically and geometrically thick torus at sub-parsec scale. However, it is not clear how is the mass supply…

Astrophysics of Galaxies · Physics 2018-12-24 Yuki Kudoh , Keiichi Wada

We investigate sustenance and dependence on magnetic Prandtl number (${\rm Pm}$) for magnetorotational instability (MRI)-driven turbulence in astrophysical Keplerian disks with zero net magnetic flux using standard shearing box simulations.…

High Energy Astrophysical Phenomena · Physics 2020-12-02 George Mamatsashvili , George Chagelishvili , Martin E. Pessah , Frank Stefani , Gianluigi Bodo

We address the question whether the magnetorotational instability (MRI) can operate in the near-surface shear layer (NSSL) of the Sun and how it affects the interaction with the dynamo process. Using hydromagnetic mean-field simulations of…

Solar and Stellar Astrophysics · Physics 2025-10-28 Axel Brandenburg , Gustav Larsson , Fabio Del Sordo , Petri J. Käpylä

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

The redistribution of angular momentum is a long standing problem in our understanding of protoplanetary disk (PPD) evolution. The magnetorotational instability (MRI) is considered a likely mechanism. We present the results of a study…

Solar and Stellar Astrophysics · Physics 2016-12-07 Donna Rodgers-Lee , Tom P. Ray , Turlough P. Downes

It is widely known that cosmic magnetic fields, i.e. the fields of planets, stars, and galaxies, are produced by the hydromagnetic dynamo effect in moving electrically conducting fluids. It is less well known that cosmic magnetic fields…

Astrophysics · Physics 2009-05-13 Frank Stefani , Agris Gailitis , Gunter Gerbeth

We carried out global three-dimensional magneto-hydrodynamic simulations of dynamo activities in galactic gaseous disks without assuming equatorial symmetry. Numerical results indicate the growth of azimuthal magnetic fields non-symmetric…

Astrophysics of Galaxies · Physics 2015-06-12 Mami Machida , Kenji E. Nakamura , Takahiro Kudoh , Takuya Akahori , Sofue Yoshiaki , Ryoji Matsumoto

The formation of binary stars is highly influenced by magnetic fields, which play a crucial role in transporting angular momentum. We conducted three-dimensional numerical simulations of binary star accretion via a circumbinary disk, taking…

Solar and Stellar Astrophysics · Physics 2024-02-06 Tomoaki Matsumoto

Magnetically mediated disk outflows are a leading paradigm to explain winds and jets in a variety of astrophysical sources, but where do the fields come from? Since accretion of mean magnetic flux may be disfavored in a thin turbulent disk,…

Astrophysics · Physics 2009-11-10 Eric G. Blackman , Jonathan C. Tan