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Related papers: MRI: a possible mechanism for funnel flows?

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Current magnetic resonance imaging (MRI) requires the subject to remain stationary to limit motion artifacts and avoid unwanted field-induced brain stimulation. However, imaging during large-scale motion could enable studies in which motion…

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 study how the magnetorotational instability (MRI) in protoplanetary disks is affected by the electric discharge caused by the electric field in the resistive MHD. We have performed three-dimensional shearing box simulations with various…

Solar and Stellar Astrophysics · Physics 2015-06-11 Takayuki Muranushi , Satoshi Okuzumi , Shu-ichiro Inutsuka

We analyze the stability of a thin plasma disk which is rotating around a compact astrophysical object and is embedded in the strong magnetic field of such a source. The aim of this study is the determination of a new type of unstable…

Solar and Stellar Astrophysics · Physics 2015-06-17 Giovanni Montani , Riccardo Benini , Nakia Carlevaro , Alessio Franco

The emergence of turbulence in shear flows is a well-investigated field. Yet, one of major issues is the apparent contradiction between linear stability analysis quoting a flow to be stable and results from experiments and simulations…

High Energy Astrophysical Phenomena · Physics 2018-09-28 Tanayveer Singh Bhatia , Banibrata Mukhopadhyay

The local properties of turbulence driven by the magnetorotational instability (MRI) in rotating, shearing flows are studied in the framework of a shearing-box model. Based on numerical simulations, we propose that the MRI-driven turbulence…

Solar and Stellar Astrophysics · Physics 2015-12-14 Justin Walker , Geoffroy Lesur , Stanislav Boldyrev

[Abridged] Aims. We provide an important step toward a better understanding of the magnetorotational instability (MRI)-dust coevolution in protoplanetary disks by presenting a proof of concept that dust evolution ultimately plays a crucial…

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…

We use a global magnetohydrodynamic simulation of a geometrically thin accretion disk to investigate the locality and detailed structure of turbulence driven by the magnetorotational instability (MRI). The model disk has an aspect ratio $H…

High Energy Astrophysical Phenomena · Physics 2015-05-28 Kris Beckwith , Philip J. Armitage , Jacob B. Simon

The standard magnetorotational instability (SMRI) is widely believed to be responsible for the observed accretion rates in astronomical disks. It is a linear instability triggered in the differentially rotating ionized disk flow by a…

High Energy Astrophysical Phenomena · Physics 2024-11-05 Yin Wang , Fatima Ebrahimi , Hongke Lu , Jeremy Goodman , Erik P. Gilson , Hantao Ji

The MHD flow driven by a travelling magnetic field (TMF) in an annular channel is investigated numerically. For sufficiently large magnetic Reynolds number Rm, or if a large enough pressure gradient is externally applied, the system…

Fluid Dynamics · Physics 2016-03-23 Christophe Gissinger , Paola Rodriguez-Imazio , Stephan Fauve

Geometrically thick tori with constant specific angular momentum have been widely used in the last decades to construct numerical models of accretion flows onto black holes. Such discs are prone to a global non-axisymmetric hydrodynamic…

High Energy Astrophysical Phenomena · Physics 2017-10-19 Matteo Bugli , Jérôme Guilet , Ewald Müller , Luca Del Zanna , Niccolò Bucciantini , Pedro J. Montero

Possible effects of magnetic fields in core collapse supernovae rely on an efficient amplification of the weak pre-collapse fields. It has been suggested that the magneto-rotational instability (MRI) leads to rapid field growth. Although…

Astrophysics · Physics 2009-05-06 M. Obergaulinger , P. Cerdà-Duràn , E. Müller , M. A. Aloy

The structure and dynamics of diffuse gas in the Milky Way and other disk galaxies may be strongly influenced by thermal and magnetorotational instabilities (TI and MRI) on scales of about 1-100 pc. We initiate a study of these processes,…

Astrophysics · Physics 2009-11-10 Robert A. Piontek , Eve C. Ostriker

In Keplerian accretion disks, turbulence and magnetic fields may be jointly excited through a subcritical dynamo process involving the magnetorotational instability (MRI). High-resolution simulations exhibit a tendency towards statistical…

High Energy Astrophysical Phenomena · Physics 2017-02-08 A. Riols , F. Rincon , C. Cossu , G. Lesur , G. I. Ogilvie , P-Y. Longaretti

Previously we demonstrated that the magnetorotational instability (MRI) grows vigorously in eccentric disks, much as it does in circular disks, and we investigated the nonlinear development of the eccentric MRI without vertical gravity.…

High Energy Astrophysical Phenomena · Physics 2025-05-07 Chi-Ho Chan , Tsvi Piran , Julian H. Krolik

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

The saturation level of the magnetorotational instability (MRI) is investigated using three-dimensional MHD simulations. The shearing box approximation is adopted and the vertical component of gravity is ignored, so that the evolution of…

Astrophysics · Physics 2009-11-10 Takayoshi Sano , Shu-ichiro Inutsuka , Neal J. Turner , James M. Stone

We analyze the linear stability of an axially symmetric ideal plasma disk, embedded in a magnetic field and endowed with a differential rotation. This study is performed by adopting the magnetic flux function as the fundamental dynamical…

High Energy Astrophysical Phenomena · Physics 2016-07-26 G. Montani , F. Cianfrani , D. Pugliese

We discuss the relevance of the magnetorotational instability (MRI) in core-collapse supernovae (CCSNe). Our recent numerical studies show that in CCSNe, the MRI is terminated by parasitic instabilities of the Kelvin-Helmholtz type. To…

High Energy Astrophysical Phenomena · Physics 2017-07-05 Tomasz Rembiasz , Martin Obergaulinger , Jérôme Guilet , Pablo Cerdá-Durán , Miguel-Ángel Aloy , E. Müller