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Related papers: MRI-driven $\alpha-\Omega$ dynamos in protoneutron…

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Magnetorotational instability (MRI)-driven turbulence and dynamo phenomena are analyzed using direct statistical simulations. Our approach begins by developing a unified mean-field model that combines the traditionally decoupled problems of…

High Energy Astrophysical Phenomena · Physics 2025-05-07 Tushar Mondal , Pallavi Bhat

In this paper we make an effort to understand the interaction of turbulence generated by the magnetorotational instability (MRI) with turbulence from other sources, such as supernova explosions (SNe) in galactic disks. First we perform a…

Astrophysics of Galaxies · Physics 2015-05-14 Maarit J. Korpi , Petri J. Käpylä , Miikka S. Väisälä

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

I review the effects of magnetic fields on star formation in galaxies. This includes the effects of the magnetorotational instability (MRI) at galactic scales, magneto-Jeans and swing instabilities, Parker instabilities, and the effects of…

Astrophysics · Physics 2008-04-16 Mordecai-Mark Mac Low

A series of numerical simulations on magnetorotational core-collapse supernovae are carried out. Dipole-like configurations which are offset northward are assumed for the initially strong magnetic fields together with rapid differential…

Astrophysics · Physics 2009-11-13 Hidetomo Sawai , Kei Kotake , Shoichi Yamada

Current models of magnetars require extremely strong magnetic fields to explain their observed quiescent and bursting emission, implying that the field strength within the star's outer crust is orders of magnitude larger than the dipole…

Solar and Stellar Astrophysics · Physics 2016-04-07 Konstantinos N. Gourgouliatos , Toby Wood , Rainer Hollerbach

We investigated the impacts of magnetorotational instability (MRI) on the dynamics of weakly magnetized, rapidly rotating core-collapse by conducting high resolution MHD simulations in axisymmetry with simplified neutrino transfer. We found…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Hidetomo Sawai , Shoichi Yamada

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

Turbulence and dynamo induced by the magnetorotational instability (MRI) are analyzed using quasi-linear statistical simulation methods. It is found that homogenous turbulence is unstable to a large scale dynamo instability, which saturates…

High Energy Astrophysical Phenomena · Physics 2015-06-01 Jonathan Squire , Amitava Bhattacharjee

Rapidly rotating magnetars have been associated with gamma-ray bursts (GRBs) and super-luminous supernovae (SLSNe). Using a suite of 2D magnetohydrodynamic simulations at fixed neutrino luminosity and a couple of evolutionary models with…

High Energy Astrophysical Phenomena · Physics 2023-10-24 Tejas Prasanna , Matthew S. B. Coleman , Matthias J. Raives , Todd A. Thompson

Supernovae are known to be the dominant energy source for driving turbulence in the interstellar medium. Yet, their effect on magnetic field amplification in spiral galaxies is still poorly understood. Analytical models based on the…

Astrophysics of Galaxies · Physics 2010-01-29 Oliver Gressel

We have investigated the turbulent mean-field dynamo action in protoneutron stars that are subject to convective and neutron finger instabilities during the early evolutionary phase. While the first one develops mostly in the inner regions…

Astrophysics · Physics 2009-11-11 A. Bonanno , V. Urpin , G. Belvedere

Because of their neutron-richness and association with supernovae, post-explosion protoneutron star winds are thought to be a likely astrophysical site for rapid neutron capture nucleosynthesis (the r-process). However, the most recent…

Astrophysics · Physics 2009-11-07 Todd A. Thompson

Following a binary neutron star (BNS) merger, the transient remnant is often a fast-spinning, differentially rotating, magnetised hypermassive neutron star (HMNS). This object is prone to the magnetorotational instability (MRI) which drives…

High Energy Astrophysical Phenomena · Physics 2025-12-24 Miquel Miravet-Tenés , Martin Obergaulinger , Pablo Cerdá-Durán , José A. Font , Milton Ruiz

We numerically investigate the generation of a magnetic field in a protostellar disc via an $\alpha \Omega$-dynamo and the resulting magnetohydrodynamic (MHD) driven outflows. We find that for small values of the dimensionless dynamo…

High Energy Astrophysical Phenomena · Physics 2018-03-05 Sergei Dyda , Richard V. E. Lovelace , Galina V. Ustyugova , Alexander V. Koldoba , Ira Wasserman

Stratified disks with strong horizontal magnetic fields are susceptible to magnetic buoyancy instability (MBI). Modifying the magnetic field and gas distributions, this can play an important role in galactic evolution. The MBI and the…

Astrophysics of Galaxies · Physics 2023-12-05 Yasin Qazi , Anvar Shukurov , Devika Tharakkal , Frederick A. Gent , Abhijit B. Bendre

We consider a newly-born millisecond magnetar, focusing on its interaction with the dense stellar plasma in which it is initially embedded. We argue that the confining pressure and inertia of the surrounding plasma acts to collimate the…

Astrophysics · Physics 2009-11-11 Dmitri A. Uzdensky , Andrew I. MacFadyen

Bearing in mind the application to core-collapse supernovae, we study nonlinear properties of the magneto-rotational instability (MRI) by means of three- dimensional simulations in the framework of a local shearing box approximation. By…

Solar and Stellar Astrophysics · Physics 2015-06-11 Y. Masada , T. Takiwaki , K. Kotake , T. Sano

Magnetorotational instability (MRI) is the most promising mechanism behind accretion in low-mass protostellar disks. Here we present the first analysis of the global structure and evolution of non-ideal MRI-driven T-Tauri disks on…

Earth and Planetary Astrophysics · Physics 2015-06-15 Russell Landry , Sarah E. Dodson-Robinson , Neal J. Turner , Greg Abram

A relatively modest value of the initial rotation of the iron core, a period of ~ 6-31 s, will give a very rapidly rotating protoneutron star and hence strong differential rotation with respect to the infalling matter. Under these…

Astrophysics · Physics 2007-05-23 Shizuka Akiyama , J. Craig Wheeler