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This paper is concerned with the kinetic treatment of quasi-stationary axisymmetric collisionless accretion disc plasmas. The conditions of validity of the kinetic description for non-relativistic magnetized and gravitationally-bound…

High Energy Astrophysical Phenomena · Physics 2023-06-29 Claudio Cremaschini , Massimo Tessarotto

In the present work, accretion onto a static spherically symmetric black hole in the hybrid metric-Palatini gravity is considered. The Novikov-Thorne model for a relativistic thin accretion disk is used. The energy flux, temperature…

General Relativity and Quantum Cosmology · Physics 2024-02-05 P. I. Dyadina , N. A. Avdeev

Molecular gas disks are generally Toomre stable ($Q_T>$1) and yet clearly gravitationally unstable to structure formation as evidenced by the existence of molecular clouds and ongoing star formation. This paper adopts a 3D perspective to…

Astrophysics of Galaxies · Physics 2022-10-12 Sharon E. Meidt

A systematic theory of the asymptotic expansion of the magnetohydrodynamic (MHD) equilibrium in the distance from the magnetic axis is developed to include arbitrary smooth currents near the magnetic axis. Compared to the vacuum and the…

Plasma Physics · Physics 2024-02-28 W. Sengupta , E. Rodriguez , R. Jorge , M. Landreman A. Bhattacharjee

The inward flow of matter through accretion disks is driven by MHD turbulence. Global general relativistic MHD simulations shed quantitative light on this process, revealing a number of aspects of accretion previously unrecognized. Among…

Astrophysics · Physics 2008-11-26 J. H. Krolik , J. F. Hawley

The effect of magnetic field diffusion on the stability of accretion disks is a problem that has attracted considerable interest of late. In particular, the Hall effect has the potential to bring about remarkable changes in the dynamical…

Earth and Planetary Astrophysics · Physics 2017-03-29 Gopakumar Mohandas , Martin E. Pessah

We extend the work by Appl and Camenzind (1988) for special relativistic magnetohydrodynamic (MHD) jets, to fully general relativistic studies of the standing shock formation for accreting MHD plasma in a rotating, stationary and…

Astrophysics · Physics 2009-11-07 Masaaki Takahashi , Darrell Rilett , Keigo Fukumura , Sachiko Tsuruta

We investigate the viscous stability of thin, Keplerian accretion disks in regions where general relativistic (GR) effects are essential. For gas pressure dominated (GPD) disks, we show that the Newtonian conclusion that such disks are…

Astrophysics · Physics 2009-10-30 Pranab Ghosh

We investigate stationary, self-gravitating, magnetised disks (or tori) around black holes. The models are obtained by numerically solving the coupled system of the Einstein equations and the equations of ideal general-relativistic…

General Relativity and Quantum Cosmology · Physics 2019-06-05 Patryk Mach , Sergio Gimeno-Soler , Jose A. Font , Andrzej Odrzywolek , Michal Pirog

We present two generalized hybrid kinetic-Hall magnetohydrodynamics (MHD) models describing the interaction of a two-fluid bulk plasma, which consists of thermal ions and electrons, with energetic, suprathermal ion populations described by…

Plasma Physics · Physics 2021-11-11 D. A. Kaltsas , G. N. Throumoulopoulos , P. J. Morrison

We briefly review recent developments in black hole accretion disk theory, emphasizing the vital role played by magnetohydrodynamic (MHD) stresses in transporting angular momentum. The apparent universality of accretion-related outflow…

Astrophysics · Physics 2009-06-23 Zdenka Kuncic , Geoffrey V. Bicknell

It is known that, for a static fluid sphere, the GeneralRelativistic (GR) Effective Mass Energy Density (EMD) appears to be (rho + 3 p), where rho is the bare mass density, p is the isotropic pressure, from a purely localized view point.…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Abhas Mitra

Using the Grad-Shafranov equation, we consider a new analytical model of the black hole magnetosphere based on the assumption that the magnetic field is radial near the horizon and uniform (cylindrical) in the jet region. Within this model,…

High Energy Astrophysical Phenomena · Physics 2013-03-12 V. S. Beskin , A. A. Zheltoukhov

Axisymmetric accretion disks in vicinity of a central compact body are studied. For the simple models such as vertically isothermal disks as well as adiabatic ones the exact solutions to the steady-state MHD (magneto-hydrodynamic) system…

Solar and Stellar Astrophysics · Physics 2013-09-06 V. S. Borisov

Recent results of the event horizon-scale images of M87* and Sagittarius A* from the Event Horizon Telescope Collaboration show that strong magnetic fields are likely present around the central black holes (BHs) in these sources.…

High Energy Astrophysical Phenomena · Physics 2025-09-19 Koushik Chatterjee , Matthew Liska , Alexander Tchekhovskoy , Sera Markoff , Ramesh Narayan

In the solid crusts of neutron stars, the advection of the magnetic field by the current-carrying electrons, an effect known as Hall drift, should play a very important role as the ions remain essentially fixed (as long as the solid does…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Pablo Marchant , Andreas Reisenegger , Juan Alejandro Valdivia , Jaime H. Hoyos

We study the evolution in axisymmetry of accretion disks formed self-consistently through collapse of magnetized hypermassive neutron stars to black holes. Such stars can arise following the merger of binary neutron stars. They are…

Astrophysics · Physics 2008-12-18 Branson C. Stephens , Yuk Tung Liu , Stuart L. Shapiro

Aims. A realistic model of magnetic linkage between a central object and its accretion disk is a prerequisite for understanding the spin history of stars and stellar remnants. To this end, we aim to provide an analytic model in agreement…

Solar and Stellar Astrophysics · Physics 2023-10-04 Miljenko Čemeljić , Włodek Kluźniak , Varadarajan Parthasarathy

Recent work on the transport of angular momentum in accretion disks suggests that the Velikhov-Chandrasekhar instability, in which a large scale magnetic field generates small scale eddys in a shearing environment, may be ultimately…

Astrophysics · Physics 2007-05-23 E. T. Vishniac

Hall drift, i. e., transport of magnetic flux by the moving electrons giving rise to the electrical current, may be the dominant effect causing the evolution of the magnetic field in the solid crust of neutron stars. It is a nonlinear…

Astrophysics · Physics 2009-11-13 Andreas Reisenegger , Rafael Benguria , Joaquin P. Prieto , Pablo A. Araya , Dong Lai