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Related papers: The Magnetorotational Instability in Core Collapse…

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We examine the stability of standing, spherical accretion shocks. Accretion shocks arise in core collapse supernovae (the focus of this paper), star formation, and accreting white dwarfs and neutron stars. We present a simple analytic model…

Astrophysics · Physics 2009-11-07 John M. Blondin , Anthony Mezzacappa , Christine DeMarino

Hypermassive neutron stars (HMNSs) are equilibrium configurations supported against collapse by rapid differential rotation and likely form as transient remnants of binary neutron star mergers. Though HMNSs are dynamically stable, secular…

The magnetohydrodynamical behavior (MHD) of accretion disks is reviewed. A detailed presentation of the fundamental MHD equations appropriate for protostellar disks is given. The combination of a weak (subthermal) magnetic field and…

Solar and Stellar Astrophysics · Physics 2009-06-05 Steven A. Balbus

We present three-dimensional hydrodynamic and magnetohydrodynamic core-collapse supernova simulations of a rapidly rotating, high-compactness $39 M_\odot$ progenitor to investigate the roles of rotation and magnetic fields in shock revival…

High Energy Astrophysical Phenomena · Physics 2026-05-19 Liubov Kovalenko , Evan O'Connor , Haakon Andresen , Sean M. Couch

At second order in perturbation theory, the unstable r-mode of a rotating star includes growing differential rotation whose form and growth rate are determined by gravitational-radiation reaction. With no magnetic field, the angular…

High Energy Astrophysical Phenomena · Physics 2018-03-05 John L. Friedman , Lee Lindblom , Luciano Rezzolla , Andrey I. Chugunov

We investigate where in protoplanetary disks magnetorotational instability operates, which can cause angular momentum transport in the disks. We investigate the spatial distribution of various charged particles and the unstable regions for…

Astrophysics · Physics 2009-10-31 Takayoshi Sano , Shoken M. Miyama , Toyoharu Umebayashi , Takenori Nakano

We analyze the linear growth of the magnetorotational instability (MRI) in the short time limit using nonmodal methods. Our findings are quite different to standard results, illustrating that shearing wave energy can grow at the maximum MRI…

Plasma Physics · Physics 2014-12-01 Jonathan Squire , Amitava Bhattacharjee

The magnetorotational instability (MRI) triggers turbulence and enables outward transport of angular momentum in hydrodynamically stable rotating shear flows, e.g., in accretion disks. What laws of differential rotation are susceptible to…

Solar and Stellar Astrophysics · Physics 2012-07-13 Oleg N. Kirillov , Frank Stefani

The central engine of gamma-ray bursts (GRBs) is believed to be a hot and dense disk with hyperaccretion onto a few solar-mass black hole. We investigate where the magnetorotational instability (MRI) actively operates in the hyperaccretion…

Astrophysics · Physics 2011-02-11 Youhei Masada , Norita Kawanaka , Takayoshi Sano , Kazunari Shibata

All experiments, which have been proposed so far to model the magnetorotational instability (MRI) in the laboratory, involve a Couette flow of liquid metals in a rotating annulus. All liquid metals have small magnetic Prandtl numbers, Pm,…

Astrophysics · Physics 2009-11-10 Koichi Noguchi , Vladimir I. Pariev

We calculate growth rates for nonaxisymmetric instabilities including the magnetorotational instability (MRI) throughout the Sun. We first derive a dispersion relation for nonaxisymmetric instability including the effects of shear,…

Solar and Stellar Astrophysics · Physics 2015-06-22 Daniel Kagan , J. Craig Wheeler

(Abriged) The magnetorotational instability (MRI) is believed to be an efficient way to transport angular momentum in accretion discs. It has also been suggested as a way to amplify magnetic fields in discs, the instability acting as a…

Astrophysics · Physics 2009-11-13 G. Lesur , G. I. Ogilvie

Black hole superradiance has proven being very valuable in several realms of gravitational physics, and holds a promising discovery potential. In this paper, we consider the superradiant instability of magnetically-charged, rotating black…

General Relativity and Quantum Cosmology · Physics 2025-01-22 David Pereñiguez , Marina de Amicis , Richard Brito , Rodrigo Panosso Macedo

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 $m=1$ oscillations and instabilities of magnetised neutron stars, by numerical time-evolution of linear perturbations of the system. The background stars are stationary equilibrium configurations with purely toroidal magnetic…

Solar and Stellar Astrophysics · Physics 2015-05-19 S. K. Lander , D. I. Jones

Measuring the rotation of core-collapse supernovae (SN) and of their progenitor stars is extremely challenging. Here it is demonstrated that neutrinos may potentially be employed as stellar gyroscopes, if phases of activity by the standing…

High Energy Astrophysical Phenomena · Physics 2018-12-12 Laurie Walk , Irene Tamborra , Hans-Thomas Janka , Alexander Summa

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

We examine the linear stability of a flow threaded by a weak, vertical magnetic field in a disk with a keplerian rotation profile and a vertical stratification of the ionization degree as that predicted for vast portions of protoplanetary…

Astrophysics · Physics 2009-10-31 Mauricio Reyes-Ruiz

The interaction between weak magnetic fields and rotation can lead to instabilities that transport angular momentum (AM) and chemical elements affecting the evolution of massive stars. We explore the effects of the magneto-rotational…

Solar and Stellar Astrophysics · Physics 2022-09-28 A. Griffiths , G. Meynet , P. Eggenberger , F. Moyano , M. A. Aloy

The magnetic fields affect collapse of molecular cloud cores. Here, we consider a collapsing core with an axial magnetic field and investigate its effect on infall of matter and formation of accretion disk. For this purpose, the equations…

Astrophysics of Galaxies · Physics 2015-05-27 Mohsen Nejad-Asghar