19-23 October 2020
Europe/Prague timezone
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Magnetically Ejected Disks: Equatorial Outflows Near Vertically Magnetized Black Hole

20 Oct 2020, 16:25


Vladimír Karas (Astronomical Institute, Czech Academy of Sciences)


Black holes attract gaseous material from the surrounding environment. Cosmic plasma is largely ionized magnetized because of electric currents flowing in the highly conductive environment near black holes; the process of accretion then carries the magnetic flux onto the event horizon, $r\simeq R_+$. On the other hand, magnetic pressure acts against accretion. It can not only arrest the inflow but it can even push the plasma away from the black hole if the magnetic repulsion prevails. The black hole does not hold the magnetic field by itself. In this contribution we show an example of an equatorial outflow driven by a large scale magnetic field. We initiate our computations with an axially symmetric configuration of a uniform (Wald) magnetic field aligned with the common rotation axis of the black hole and the accretion disk. For the fluid distribution we assume a spherically symmetric (Bondi) accretion flow infalling initially onto the black hole from a large distance, $r\gg R_+$. Then we evolve the initial configuration in the force-free limit of a perfectly conducting fluid. We observe how the magnetic lines of force start accreting with the plasma while an equatorial intermittent outflow develops and goes on ejecting some material away from the black hole.

Primary author

Vladimír Karas (Astronomical Institute, Czech Academy of Sciences)


Kostas Sapountzis (Center for Theoretical Physics, Polish Academy of Science) Agnieszka Janiuk (Center for Theoretical Physics, Polish Academy of Science)

Presentation Materials