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We present a magneto-hydrodynamic model developed for investigations of advective non-stationary, asymmetric Keplerian accretion disks in the normal magnetic field. The introduced model allows us to trace the evolution in different fixed…

High Energy Astrophysical Phenomena · Physics 2014-08-19 Krasimira Yankova , Lachezar Filipov

We examine a thick accretion disc in the presence of external gravity and intrinsic dipolar magnetic field due to a non-rotating central object. In this paper, we generalize the Newtonian theory of stationary axisymmetric resistive tori of…

High Energy Astrophysical Phenomena · Physics 2016-03-16 M. Shaghaghian

The model of a geometrically thin gaseous disk in the external gravitational potential is considered. The dinamics of small nonaxisymmetric perturbations in the plane of the accretion disk with dissipative effects is investigated. It is…

Astrophysics · Physics 2009-10-30 A. V. Khoperskov , S. S. Khrapov

The stability properties of inviscid protostellar disks are examined taking into account the Hall effect and buoyancy. Depending on the parameters, different types of instabilities can exist in different regions of disks. In a very low…

Astrophysics · Physics 2016-08-16 V. Urpin , G. Rüdiger

In toroidal geometry, and prior to the establishment of a fully developed turbulent state, the so-called topological instability of the pressure-gradient-driven turbulence is observed. In this intermediate state, a narrow spectral band of…

We present a novel approach to study the global structure of steady, axisymmetric, advective, geometrically thin, magnetohydrodynamic (MHD) accretion flow around black holes in full general relativity (GR). Considering ideal MHD conditions…

High Energy Astrophysical Phenomena · Physics 2022-10-05 Samik Mitra , Debaprasad Maity , Indu Kalpa Dihingia , Santabrata Das

We investigate accretion onto a central star, with the size, rotation rate, and magnetic dipole of a young stellar object, to study the flow pattern (velocity and density) of the fluid within and outside of the disc. We perform resistive…

Solar and Stellar Astrophysics · Physics 2023-06-14 R. Mishra , M. Čemeljić , W. Kluźniak

We propose a new model for these QPOs based on forced oscillations induced in the accretion disk due to the stellar magnetic field. First, it is shown that a magnetized accretion disk evolving in a rotating nonaxisymmetric magnetic field…

Astrophysics · Physics 2016-08-30 J. Pétri

Accretion discs are composed of ionized gas in motion around a central object. Sometimes, the disc is the source of powerful bipolar jets along its rotation axis. Theoretical models invoke the existence of a bipolar magnetic field crossing…

High Energy Astrophysical Phenomena · Physics 2011-12-23 Remi de Guiran , Jonathan Ferreira

The global evolution of protoplanetary disks (PPDs) has recently been shown to be largely controlled by the amount of poloidal magnetic flux threading the disk, which is further controlled by the poorly understood process of magnetic flux…

Earth and Planetary Astrophysics · Physics 2017-02-15 Xue-Ning Bai , James M. Stone

Magnetically driven microparticles provide a versatile platform for probing and manipulating biological systems, yet the physical framework governing their actuation in complex environments remains only partially explored. Within the field…

Soft Condensed Matter · Physics 2025-10-15 Andrea Visonà , Robert Morel , Hélène Joisten , Bernard Dieny , Alice Nicolas

We study an accretion disk in which three different regions may coexist: MHD turbulent regions, dead zones and gravitationally unstable regions. Although the dead zones are stable, there is some transport due to the Reynolds stress…

Astrophysics · Physics 2009-11-13 Caroline E. J. M. L. J. Terquem

A convenient representation of the structure of the large-scale galactic magnetic field is required for the interpretation of polarization data in the sub-mm and radio ranges, in both the Milky Way and external galaxies. We develop a simple…

Astrophysics of Galaxies · Physics 2019-03-14 Anvar Shukurov , Luiz Felippe S. Rodrigues , Paul J. Bushby , James Hollins , Jorg P. Rachen

Hydromagnetic stresses in accretion discs have been the subject of intense theoretical research over the past one and a half decades. Most of the disc simulations have assumed a small initial magnetic field and studied the turbulence that…

Astrophysics · Physics 2009-11-13 Anders Johansen , Yuri Levin

The dynamical foundations of $\alpha$ disk models are described. At the heart of the viscous formalism of accretion disk models are correlations in the fluctuating components of the disk velocity, magnetic field, and gravitational…

Astrophysics · Physics 2009-10-31 S. A. Balbus , J. C. B. Papaloizou

Observations of clusters of galaxies show ubiquitous presence of X-ray cavities, presumably blown by the AGN jets. We consider magnetic field structures of these cavities. Stability requires that they contain both toroidal and poloidal…

High Energy Astrophysical Phenomena · Physics 2015-05-19 Konstantinos Nektarios Gourgouliatos , Jonathan Braithwaite , Maxim Lyutikov

The main aim of this paper is studying the effect of toroidal magnetic field on the structure of Advection-Dominated Accretion Flows (ADAF) in the presence of the turbulence viscosity and diffusivity due to viscosity and magnetic field…

High Energy Astrophysical Phenomena · Physics 2015-06-17 Amin Mosallanezhad , Shahram Abbassi , Nasim Beiranvand

The evolution of the magnetic field from the large-scale dynamo is considered a central feature of the accretion disk around a black hole. The resulting low-frequency oscillations introduced from the growth and decay of the field strength,…

High Energy Astrophysical Phenomena · Physics 2018-07-11 J. Drew Hogg , Christopher Reynolds

New three dimensional magnetohydrodynamic simulations of accretion disk dynamics in a pseudo-Newtonian Paczynski-Wiita potential are presented. These have finer resolution in the inner disk than any previously reported. Finer resolution…

Astrophysics · Physics 2009-11-07 John F. Hawley , Julian H. Krolik

Discretized numerical simulations are a powerful tool for investigation of nonlinear MHD turbulence in accretion disks. However, confidence in their quantitative predictions requires a demonstration that further refinement of the spatial…

High Energy Astrophysical Phenomena · Physics 2015-05-27 John F. Hawley , Xiaoyue Guan , Julian H. Krolik