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The aberrated radiation pressure at the inner edge of the accretion disk around an astrophysical black hole imparts a relative azimuthal velocity on the electrons with respect to the ions which gives rise to a ring electric current that…

High Energy Astrophysical Phenomena · Physics 2015-06-03 Ioannis Contopoulos , Antonios Nathanail , Matthaios Katsanikas

We revisit the problem of magnetic field generation in accretion flows onto black holes owing to the excess radiation force on electrons. This excess force may arise from the Poynting-Robertson effect. Instead of a recent claim of the…

Astrophysics · Physics 2009-11-07 G. S. Bisnovatyi-Kogan , R. V. E. Lovelace , V. A. Belinski

We present our view of the immediate environment of an astrophysical black hole. We discuss the origin of the electron-positron and electron-proton jet components, and the origin of the large-scale magnetic field. We show how the aberrated…

High Energy Astrophysical Phenomena · Physics 2019-01-11 Ioannis Contopoulos

We investigate the dynamics of radiation in an astrophysical accretion disk around a Kerr black hole. The source of the radiation is the accretion disk itself, and not a central object as in previous studies of the Poynting-Robertson…

High Energy Astrophysical Phenomena · Physics 2015-06-19 Leela E. Koutsantoniou , Ioannis Contopoulos

We reinvestigate the generation and accumulation of magnetic flux in optically thin accretion flows around active gravitating objects. The source of the magnetic field is the azimuthal electric current associated with the Poynting-Robertson…

We show that the Poynting-Robertson drag effect in an optically thin advection-dominated accretion flow around active gravitating objects generates strong azimuthal electric currents which give rise to astrophysically significant magnetic…

Astrophysics · Physics 2009-10-30 Ioannis Contopoulos , Demosthenes Kazanas

Combined influence of rotation of a black hole and ambient magnetic fields creates conditions for powerful astrophysical processes of accretion and outflow of matter which are observed in many systems across the range of masses; from…

High Energy Astrophysical Phenomena · Physics 2023-07-26 Ondrej Kopacek , Vladimir Karas

Astrophysical accretion flows are associated with energetic emission of radiation and outflows (winds and jets). Extensive observations of these two processes in X-ray binary outbursts are available. A convincing understanding of their…

High Energy Astrophysical Phenomena · Physics 2019-01-11 Ioannis Contopoulos

We discuss the problem of the formation of a large-scale magnetic field in the accretion disks around black holes, taking into account the non-uniform vertical structure of the disk. The high electrical conductivity of the outer layers of…

High Energy Astrophysical Phenomena · Physics 2012-08-07 G. S. Bisnovatyi-Kogan , A. S. Klepnev , R. V. E. Lovelace

The structure and magnitude of the electromagnetic field produced by a rotating accretion disk around a black hole were determined. The disk matter is assumed to be a magnetized plasma with a frozenin poloidal magnetic field. The vacuum…

Astrophysics · Physics 2009-11-07 A. A. Shatskiy

The large-scale magnetic field threading an accretion disk plays an important role in launching jets/outflows. The field may probably be advected inwards by the plasma in the accretion disk from the ambient environment (interstellar medium…

High Energy Astrophysical Phenomena · Physics 2019-02-27 Jiawen Li , Xinwu Cao

What is meant by the "inner edge" of an accretion disk around a black hole depends on the property that defines the edge. We discuss four such definitions using data from recent high-resolution numerical simulations. These are: the…

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

We describe the results of numerical "2.5--dimensional" MHD simulations of an initially unmagnetized disk model orbiting a central point--mass and responding to the continual generation of poloidal magnetic field due to a secular source…

Astrophysics · Physics 2009-11-13 Dimitris M. Christodoulou , Ioannis Contopoulos , Demosthenes Kazanas

We reconsider the problem of the formation of a large-scale magnetic field in the accretion disks around black holes. In contrast with previous work we take into account the nonuniform vertical structure of the disk. The high electrical…

Astrophysics · Physics 2009-11-13 G. S. Bisnovatyi-Kogan , R. V. E. Lovelace

The dynamics and structure of accretion disks, which accumulate the vertical magnetic field in the centers, are investigated using two- and three-dimensional MHD simulations. The central field can be built up to the equipartition level and…

Astrophysics · Physics 2009-11-13 Igor V. Igumenshchev

We discuss the problem of the formation of a large-scale magnetic field in the accretion disks around black holes, taking into account the nonuniform vertical structure of the disk. The high electrical conductivity of the outer layers of…

High Energy Astrophysical Phenomena · Physics 2011-04-27 G. S. Bisnovatyi-Kogan , R. V. E. Lovelace

Standard accretion disk theory is formulated which is based on the local heat balance. The energy produced by a turbulent viscous heating is supposed to be emitted to the sides of the disc. Sources of turbulence in the accretion disc are…

Astrophysics · Physics 2007-05-23 G. S. Bisnovatyi-Kogan

The magnetic field in an accretion disk is estimated assuming that all of the angular momentum within prescribed accretion disk radii is removed by a jet. The magnetic field estimated at the base of the jet is extrapolated to the blazar…

Astrophysics · Physics 2009-06-23 Geoffrey V. Bicknell , Jianke Li

The structure of the inner edge of the accretion disk around a black hole can be altered, if the matter inside the marginally stable orbit is magnetically connected to the disk. In this case, a non-zero torque is exerted on its inner edge,…

Astrophysics · Physics 2015-06-24 Xinwu Cao , Y. D. Xu

Recent studies have focused on how spinning black holes (BHs) within a binary system containing a strongly magnetized neutron star, then immersed in external magnetic fields, can acquire charge through mechanisms like the Wald process and…

High Energy Astrophysical Phenomena · Physics 2025-02-04 Audrey Trova , Eva Hackmann
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