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Дата изменения: Fri Jan 29 17:26:28 1999
Дата индексирования: Tue Oct 2 12:03:11 2012
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Поисковые слова: п п р п п р п п р п п р п п р п п р п п р п р п п р п р п п р п р п п р п р п п р п р п п р п р п п р п р п п р п р п п р п п р п р п п р п п р п р п п р п
Seminars

All-Moscow Seminar of Astrophysicists
(ASA)

The seminar is supported by the grant of Federal Programm "Integration"
annotation of talk
Bisnovaty-Kogan G.S. (IKI)
"ADVECTIVE ACCRETION DISKS WITH MAGNETIC FIELDS AROUND BLACK HOLE"


Advection-dominated, accretion flow onto a compact object, recently considered by a number of authors, assume that the dissipation of turbulent energy of the flow heats the ions and that the dissipated energy is advected inward. It leads to efficiency of conversion of accretion energy to radiation very much smaller than unity. However, when the flows have an equipartition magnetic field a dissipation of magnetic energy at a rate comparable to that for the turbulence must occur by Ohmic heating. We argue that this heating occurs as a result of plasma instabilities and that the relevant instabilities are current driven in response to the strong electric fields parallel to the magnetic field. These instabilities heat predominantly the electrons. The conclusion is that the efficiency of conversion of accretion energy to radiation cannot be very small. Some observational contaradictions to ADAF model and reasons for existence of underluminous AGN are discussed.