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Related papers: Non-linear magnetic buoyancy instability and galac…

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We describe the effects of both magnetic buoyancy and differential rotation on a disc of isothermal gas embedded in a purely azimuthal magnetic field, in order to study the evolution and interplay of Parker and shearing instabilities. Both…

Astrophysics · Physics 2016-08-30 Thierry Foglizzo , Michel Tagger

Our theoretical and numerical analysis have suggested that for low-mass main sequences stars (of the spectral classes from M5 to G0) rotating much faster than the Sun, the generated large-scale magnetic field is caused by the mean-field…

Solar and Stellar Astrophysics · Physics 2024-04-19 N. Kleeorin , I. Rogachevskii , N. Safiullin , R. Gershberg , S. Porshnev

We study the effect of the non-linear process of ambipolar diffusion (joint transport of magnetic flux and charged particles relative to neutral particles) on the long-term behavior of a non-uniform magnetic field in a one-dimensional…

Solar and Stellar Astrophysics · Physics 2015-05-18 Jaime Hoyos , Andreas Reisenegger , Juan Valdivia

This study investigates Parker instability in an interstellar medium (ISM) near the Galactic plane using three-dimensional magneto-hydrodynamic simulations. Parker instability arises from the presence of a magnetic field in a plasma,…

High Energy Astrophysical Phenomena · Physics 2011-01-06 Ying-Yi Lo , Chung-Ming Ko , Chih-Yueh Wang

Stars are, generically, rotating and magnetised objects with a misalignment between their magnetic and rotation axes. Since a magnetic field induces a permanent distortion to its host, it provides effective rigidity even to a fluid star,…

Solar and Stellar Astrophysics · Physics 2017-03-23 S. K. Lander , D. I. Jones

A fully three-dimensional computation of induction processes in a disk is performed to investigate the evolution of a large-scale magnetic field in gas-rich barred and spiral galaxies in the presence of field diffusion. As input parameters…

Astrophysics · Physics 2007-05-23 S. von Linden , K. Otmianowska-Mazur , H. Lesch , G. Skupniewicz

The origin of large-scale magnetic fields, detected in some low-mass (dwarf and irregular) galaxies via polarised synchrotron emission and Faraday rotation, remained unexplained for a long time. We suggest that mean-field dynamo can be…

Astrophysics of Galaxies · Physics 2019-10-16 Prasanta Bera , Anvar Shukurov , Kandaswamy Subramanian

We investigate the effect of the surface bipolar magnetic regions (BMR) on the large-scale dynamo distributed in the bulk of the convection zone. The study employs the nonlinear 3D mean-field dynamo model. We model the emergence of the BMR…

Solar and Stellar Astrophysics · Physics 2022-05-23 V. V. Pipin

The evolution of three-dimensional, large-scale, magnetic fields, in a galactic disk is investigated numerically. The N-body simulations of galactic dynamics are incorporated into the kinematic calculations of induction equations to study…

Astrophysics · Physics 2007-05-23 K. Otmianowska-Mazur , S. von Linden , H. Lesch , G. Skupniewicz

We explore effects of random non-axisymmetric perturbations of kinetic helicity (the $\alpha$ effect) and diffusive decay of bipolar magnetic regions on generation and evolution of large-scale non-axisymmetric magnetic fields on the Sun.…

Solar and Stellar Astrophysics · Physics 2018-11-28 V. V. Pipin , A. G. Kosovichev

A self-gravitating, differentially rotating galactic disc under vertical hydrostatic equilibrium is supported by the vertical pressure gradient force against the gravitational collapse. Such discs are known to support various bending modes…

Astrophysics of Galaxies · Physics 2023-07-13 Sagar S. Goyary , Kanak Saha , H. Shanjit Singh , Suchira Sarkar

We investigate the linear growth and vertical structure of the magnetorotational instability (MRI) in weakly ionised, stratified accretion discs. The magnetic field is initially vertical and dust grains are assumed to have settled towards…

Astrophysics · Physics 2009-11-10 Raquel Salmeron , Mark Wardle

Jetted astrophysical phenomena with black hole (BH) engines, including binary mergers, jetted tidal disruption events, and X-ray binaries, require a large-scale vertical magnetic field for efficient jet formation. However, a dynamo…

High Energy Astrophysical Phenomena · Physics 2023-11-02 Jonatan Jacquemin-Ide , François Rincon , Alexander Tchekhovskoy , Matthew Liska

A three-dimensional (3D) MHD model is applied to simulate the evolution of a large-scale magnetic field in a barred galaxy possessing a gaseous halo extending to about 2.8 kpc above the galactic plane. As the model input we use a…

Astrophysics · Physics 2009-11-07 K. Otmianowska-Mazur , D. Elstner , M. Soida , M. Urbanik

Magnetic fields in nearby, star-forming galaxies reveal both large-scale patterns and small-scale structures. A large-scale field reversal may exist in the Milky Way but no such reversals have been observed so far in external galaxies. The…

Astrophysics of Galaxies · Physics 2015-05-30 David Moss , Rodion Stepanov , Tigran Arshakian , Rainer Beck , Marita Krause , Dmitri Sokoloff

We present the results of linear analysis and two-dimensional local magnetohydrodynamic (MHD) simulations of the Parker instability, including the effects of cosmic rays (CRs), in magnetized gas disks (galactic disks). As an unperturbed…

Astrophysics · Physics 2009-11-10 Takuhito Kuwabara , Kenji Nakamura , C. M. Ko

We investigate the significance of large scale azimuthal, magnetic and velocity modes for the MRI turbulence in accretion disks. We perform 3D global ideal MHD simulations of global stratified proto-planetary disk models. Our domains span…

Solar and Stellar Astrophysics · Physics 2015-05-30 M. Flock , N. Dzyurkevich , H. Klahr , N. Turner , Th. Henning

The evolution of large-scale magnetic fields in disk galaxies is investigated numerically. The gasdynamical simulations in a disk perturbed by spiral or bar potential are incorporated into the kinematic calculations of induction equations…

Astrophysics · Physics 2007-05-23 K. Otmianowska-Mazur , M. Chiba

We perform numerical simulations of magneto-rotational instability in a local patch of accretion disk in which radiation pressure exceeds gas pressure. Such conditions may occur in the central regions of disks surrounding compact objects in…

Astrophysics · Physics 2007-05-23 N. J. Turner , J. M. Stone , T. Sano

Magnetic fields are observed beyond the peripheries of optically detected galactic discs, while numerical models of their origin and the typical magnitudes are still absent. Previously, studies of galactic dynamo have avoided considering…

Astrophysics of Galaxies · Physics 2014-09-05 E. Mikhailov , A. Kasparova , D. Moss , R. Beck , D. Sokoloff , A. Zasov