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Related papers: Linear stability of magnetized massive protoplanet…

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We study local magnetohydrodynamical (MHD) instabilities of differential rotation in magnetised, stably-stratified regions of stars and planets using a Cartesian Boussinesq model. We consider arbitrary latitudes and general shears (with…

Solar and Stellar Astrophysics · Physics 2024-10-10 Robert W. Dymott , Adrian J. Barker , Chris A. Jones , Steven M. Tobias

Axisymmetric magnetorotational instability (MRI) in viscous accretion disks is investigated by linear analysis and two-dimensional nonlinear simulations. The linear growth of the viscous MRI is characterized by the Reynolds number defined…

Astrophysics · Physics 2009-11-13 Youhei Masada , Takayoshi Sano

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

The linear instability of thin, vertically-isothermal Keplerian discs, under the influence of axial magnetic field is investigated. Solutions of the stability problem are found explicitly by asymptotic expansions in the small aspect ratio…

Solar and Stellar Astrophysics · Physics 2015-06-03 E. Liverts , Yu. Shtemler , M. Mond

In this paper, we analyze the linear stability of a stellar accretion disk, having a stratified morphology. The study is performed in the framework of ideal magneto-hydrodynamics and therefore it results in a characterization of the linear…

High Energy Astrophysical Phenomena · Physics 2016-01-20 G. Montani , D. Pugliese

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

The magneto-rotational instability (MRI) is the most likely mechanism for transportation of angular momentum and dissipation of energy within hot, ionized accretion discs. This instability is produced through the interactions of a…

High Energy Astrophysical Phenomena · Physics 2021-12-08 Oscar M. Pimentel , P. Chris Fragile , F. D. Lora-Clavijo , Bridget Ierace , Deepika Bollimpalli

We investigate the evolution of hydromagnetic perturbations in a small section of accretion disks. It is known that molecular viscosity is negligible in accretion disks. Hence, it has been argued that a mechanism, known as Magnetorotational…

High Energy Astrophysical Phenomena · Physics 2015-08-12 Sujit Kumar Nath , Banibrata Mukhopadhyay

We use smoothed particle hydrodynamics simulations of massive protostellar discs to investigate the predicted broadening of molecular lines from discs in which self-gravity is the dominant source of angular momentum transport. The…

Solar and Stellar Astrophysics · Physics 2015-06-11 Duncan H. Forgan , Philip J. Armitage , Jacob B. Simon

Massive disk fragmentation has been suggested to be one of the mechanisms leading to the formation of giant planets. While it has been heavily studied in quiescent hydrodynamic disks, the effect of MHD turbulence arising from the…

Astrophysics · Physics 2009-11-11 Sebastien Fromang

Turbulence and angular momentum transport in accretion disks remains a topic of debate. With the realization that dead zones are robust features of protoplanetary disks, the search for hydrodynamical sources of turbulence continues. A…

Earth and Planetary Astrophysics · Physics 2015-05-20 W. Lyra , H. Klahr

We investigate the stability of differentially rotating proto-neutron stars (PNSs) with a toroidal magnetic field. Stability criteria for nonaxisymmetric MHD instabilities are derived using a local linear analysis. PNSs are expected to have…

Astrophysics · Physics 2009-11-13 Youhei Masada , Takayoshi Sano , Hideaki Takabe

In the early stages of a protoplanetary disk, when its mass is a significant fraction of its star's, turbulence generated by gravitational instability (GI) should feature significantly in the disk's evolution. At the same time, the disk may…

Earth and Planetary Astrophysics · Physics 2020-03-25 Hongping Deng , Lucio Mayer , Henrik Latter

Eccentric disks arise in such astrophysical contexts as tidal disruption events, but it is unknown whether the magnetorotational instability (MRI), which powers accretion in circular disks, operates in eccentric disks as well. We examine…

High Energy Astrophysical Phenomena · Physics 2020-01-24 Chi-Ho Chan , Julian H. Krolik , Tsvi Piran

We investigate the evolution of hydromagnetic perturbations in a small section of accretion disks. It is known that molecular viscosity is negligible in accretion disks. Hence, it has been argued that Magnetorotational Instability (MRI) is…

High Energy Astrophysical Phenomena · Physics 2016-03-02 Sujit K. Nath , Banibrata Mukhopadhyay

The magnetorotational instability (MRI) has been extensively studied in circular magnetized disks, and its ability to drive accretion has been demonstrated in a multitude of scenarios. There are reasons to expect eccentric magnetized disks…

High Energy Astrophysical Phenomena · Physics 2023-12-13 Chi-Ho Chan , Tsvi Piran , Julian H. Krolik

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 key physics in accretion disks and is widely considered to play some role in massive-star core collapse. Models of rotating massive stars naturally develop very strong shear at composition…

Solar and Stellar Astrophysics · Physics 2015-06-23 J. Craig Wheeler , Daniel Kagan , Emmanouil Chatzopoulos

We analyze the magneto-rotational instability (MRI) effects on gravitational collapse and its influence on the instability critical scale. In particular, we study an axisymmetric nonstratified differentially rotating cloud, embedded in a…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-10 Giovanni Montani , Giovanni Palermo , Nakia Carlevaro

The outer protoplanetary disks (PPDs) can be subject to the magnetorotational instability (MRI) and the vertical shear instability (VSI). While both processes can drive turbulence in the disk, existing numerical simulations have studied…

Earth and Planetary Astrophysics · Physics 2022-09-21 Can Cui , Xue-Ning Bai