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Related papers: Seed fields for galactic dynamos by the magnetorot…

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The linear stability of global non-axisymmetric modes in differentially rotating, magnetized, non-ideal plasma is crucial for understanding turbulence and transport phenomena. We investigate the competition between the local…

High Energy Astrophysical Phenomena · Physics 2025-11-18 Alexander Haywood , Fatima Ebrahimi

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 venture for the comparison between growth rates for magnetorotational instability (MRI) and hydrodynamics instability in the presence of an extra force in the local Keplerian accretion flow. The underlying model is described by the…

High Energy Astrophysical Phenomena · Physics 2022-05-27 Subham Ghosh , Banibrata Mukhopadhyay

Accretion disks are highly unstable to magnetic instabilities driven by shear flow, where classically, the axisymmetric, weak-field Magneto-Rotational Instability (MRI) has received much attention through local WKB approximations. In…

High Energy Astrophysical Phenomena · Physics 2024-10-21 Nicolas Brughmans , Rony Keppens , Hans Goedbloed

Context. Regularly-spaced, star-forming regions along the spiral arms of nearby galaxies provide insight into the early stages and initial conditions of star formation. The regular separation of these star-forming regions suggests spiral…

Astrophysics of Galaxies · Physics 2024-07-24 Raghav Arora , Christoph Federrath , Robi Banerjee , Bastian Körtgen

To study some characteristics of the interstellar medium, observational data of pulsars with large Faraday rotation values (|RM|> 300 rad / m2) were used. It was suggested and justified that large |RM| values can be due to the contribution…

Astrophysics of Galaxies · Physics 2018-08-13 R. R. Andreasyan , H. R. Andreasyan , G. M. Paronyan

Magnetic fields represent a crucial aspect of the physics and astrophysics of neutron stars. Despite its great relevance, the internal magnetic field configuration of neutron stars is very poorly constrained by the observations, and…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Riccardo Ciolfi

We investigate shear and buoyancy instabilities in radially stratified, magnetized, cylindrical flows, for application to magnetocentrifugally driven winds and to magnetized accretion disks. We identify and study nine principal types of…

Astrophysics · Physics 2009-10-31 Woong-Tae Kim , Eve C. Ostriker

This paper provides a brief overview of the formation of stellar fossil magnetic fields and what potential instabilities may occur given certain configurations of the magnetic field. In particular, a purely magnetic instability can occur…

Solar and Stellar Astrophysics · Physics 2016-10-28 Kyle Augustson , Stephane Mathis , Antoine Strugarek

The gas dynamics in protoplanetary disks (PPDs) is strongly affected by non-ideal MHD effects. Using a complex chemical reaction network with standard prescriptions for X-ray and cosmic-ray ionizations, as well as the most up-to-date…

Earth and Planetary Astrophysics · Physics 2015-05-28 Xue-Ning Bai

Although playing a key role for our understanding of the evolution of galaxies, the exact way how observed galactic outflows are driven is still far from being understood and therefore our understanding of associated feedback mechanisms…

Astrophysics of Galaxies · Physics 2020-12-25 Ulrich P. Steinwandel , Klaus Dolag , Harald Lesch , Andreas Burkert

Magnetic fields are widely recognised as critical at many scales to galactic dynamics and structure, including multiphase pressure balance, dust processing, and star formation. Using imposed magnetic fields cannot reliably model the…

Astrophysics of Galaxies · Physics 2024-01-17 Frederick A. Gent , Mordecai-Mark Mac Low , Maarit J. Korpi-Lagg

The mean-field theory of magnetized stellar convection gives rise to the two possibility of distinct instabilities: the large-scale dynamo instability, operating in the bulk of the convection zone, and a negative effective magnetic pressure…

Solar and Stellar Astrophysics · Physics 2014-11-03 Sarah Jabbari , Axel Brandenburg , Illa R. Losada , Nathan Kleeorin , Igor Rogachevskii

We construct stationary global configurations of both aligned and unaligned logarithmic spiral perturbations in a composite disc system of stellar and isopedically magnetized gaseous singular isothermal discs (SIDs) coupled by gravity. The…

Astrophysics · Physics 2009-11-13 Y. -Q. Lou , Y. Wu

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

Results from simulations of hierarchical structure formation cosmology provide a tool to develop an evolutionary model of regular magnetic fields coupled to galaxy formation and evolution. We use the dynamo theory to derive the timescales…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-17 Tigran G. Arshakian , Rainer Beck , Marita Krause , Dmitry Sokolff , Rodion Stepanov

The maximum magnetic field strength generated by Weibel-type plasma instabilities is estimated for typical conditions in the interstellar medium. The relevant kinetic dispersion relations are evaluated by conducting a parameter study both…

High Energy Astrophysical Phenomena · Physics 2015-06-16 R. C. Tautz , J. Triptow

We present the results obtained from linear stability analysis and 2.5-dimensional magnetohydrodynamic (MHD) simulations of the magnetorotational instability (MRI), including the effects of cosmic rays (CRs). We took into account of the CR…

High Energy Astrophysical Phenomena · Physics 2015-03-17 Takuhito Kuwabara , Chung-Ming Ko

The intergalactic magnetic field within filaments should be less polluted by magnetised outflows from active galaxies than magnetic fields in clusters. Therefore, filaments may be a better laboratory to study magnetic field amplification by…

Astrophysics · Physics 2009-11-13 M. Bruggen , M. Ruszkowski , A. Simionescu , M. Hoeft , C. Dalla Vecchia

The magnetorotational instability (MRI) of a weakly ionized, differentially rotating, magnetized plasma disk is investigated in the multi-fluid framework. The disk is threaded by a uniform vertical magnetic field and charge is carried by…

Astrophysics · Physics 2009-11-11 B. P. Pandey , Mark Wardle