Dynamic processes during accretion into a black hole
Accretion disc theory was first developed as a theory with the local heat balance, where the whole energy produced by a viscous heating was emitted to the sides of the disc. One of the most important new invention of this theory was a phenomenological treatment of the turbulent viscosity, known as “...
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| Format: | Article |
| Language: | English |
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Wiley
2001-01-01
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| Series: | Discrete Dynamics in Nature and Society |
| Online Access: | http://dx.doi.org/10.1155/S1026022601000309 |
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| _version_ | 1832562397782474752 |
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| author | G. S. Bisonvatyi-kogan |
| author_facet | G. S. Bisonvatyi-kogan |
| author_sort | G. S. Bisonvatyi-kogan |
| collection | DOAJ |
| description | Accretion disc theory was first developed as a theory with the local heat balance, where the whole energy produced by a viscous heating was emitted to the sides of the disc. One of the most important new invention of this theory was a phenomenological treatment of the turbulent viscosity, known as “alpha” prescription, when the (rϕ) component of the stress tensor was approximated by (αP) with a unknown constant α This prescription played the role in the accretion disc theory as well important as the mixing-length theory of convection for stellar evolution. Sources of turbulence in the accretion disc are discussed, including nonlinear hydrodynamic turbulence, convection and magnetic filed role. In parallel to the optically thick geometrically thin accretion disc models, a new branch of the optically thin accretion disc models was discovered, with a larger thickness for the same total luminosity. The choice between these solutions should be done of the base of stability analysis. The ideas underlying the necessity to include advection into the accretion disc theory are presented and first models with advection are reviewed. The present status of the solution for a low-luminous optically thin accretion disc model with advection is discussed and the limits for an advection dominated accretion flows (ADAF) imposed by the presence of magnetic field are analyzed. |
| format | Article |
| id | doaj-art-4ca511d11bc741aa98d312fea68709e3 |
| institution | Kabale University |
| issn | 1026-0226 1607-887X |
| language | English |
| publishDate | 2001-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Discrete Dynamics in Nature and Society |
| spelling | doaj-art-4ca511d11bc741aa98d312fea68709e32025-02-03T01:22:39ZengWileyDiscrete Dynamics in Nature and Society1026-02261607-887X2001-01-016424726110.1155/S1026022601000309Dynamic processes during accretion into a black holeG. S. Bisonvatyi-kogan0Space Research Institute, Profsoyuznaya 84/32, Moscow 117810, RussiaAccretion disc theory was first developed as a theory with the local heat balance, where the whole energy produced by a viscous heating was emitted to the sides of the disc. One of the most important new invention of this theory was a phenomenological treatment of the turbulent viscosity, known as “alpha” prescription, when the (rϕ) component of the stress tensor was approximated by (αP) with a unknown constant α This prescription played the role in the accretion disc theory as well important as the mixing-length theory of convection for stellar evolution. Sources of turbulence in the accretion disc are discussed, including nonlinear hydrodynamic turbulence, convection and magnetic filed role. In parallel to the optically thick geometrically thin accretion disc models, a new branch of the optically thin accretion disc models was discovered, with a larger thickness for the same total luminosity. The choice between these solutions should be done of the base of stability analysis. The ideas underlying the necessity to include advection into the accretion disc theory are presented and first models with advection are reviewed. The present status of the solution for a low-luminous optically thin accretion disc model with advection is discussed and the limits for an advection dominated accretion flows (ADAF) imposed by the presence of magnetic field are analyzed.http://dx.doi.org/10.1155/S1026022601000309 |
| spellingShingle | G. S. Bisonvatyi-kogan Dynamic processes during accretion into a black hole Discrete Dynamics in Nature and Society |
| title | Dynamic processes during accretion into a black hole |
| title_full | Dynamic processes during accretion into a black hole |
| title_fullStr | Dynamic processes during accretion into a black hole |
| title_full_unstemmed | Dynamic processes during accretion into a black hole |
| title_short | Dynamic processes during accretion into a black hole |
| title_sort | dynamic processes during accretion into a black hole |
| url | http://dx.doi.org/10.1155/S1026022601000309 |
| work_keys_str_mv | AT gsbisonvatyikogan dynamicprocessesduringaccretionintoablackhole |