ISSN:
1749-6632
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Natural Sciences in General
Notes:
We have studied non-stationary and axisymmetric perturbations of a magnetohydrodynamic accretion onto a rotating (Kerr) black hole. Assuming that the magnetic field dominates the plasma accretion, we find that the meridional current becomes large near the fast-magnetosonic surface located close to the horizon. This is due to the effects of the particle's inertia and the strong gravity near the horizon. As a consequence, the fluid suffers a large radial acceleration resulting from the Lorentz force, and becomes highly variable compared with the electromagnetic field there. In fact, we further find an interesting perturbed structure of the plasma velocity with a large peak in some narrow region just beyond the fast-magnetosonic surface. If the critical surface has an oblate shape for radial poloidal field lines, this perturbation of plasma motion is induced by outgoing waves propagating from the equatorial super-fast-magnetosonic region to the polar sub-fast-magnetosonic one. Thus, the effective acceleration of particles due to the outgoing fast-magnetosonic waves will work mainly in the polar direction as a mechanism of trigger of jet production in active galactic nuclei.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1749-6632.1995.tb17604.x
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