Publication date: Mar 2012
Abstract:
We study acceleration of current-carrying string loops governed by the
presence of an outer tension barrier and an inner angular momentum
barrier in the field of Schwarzschild-de Sitter black holes. We restrict
attention to the axisymmetric motion of string loops with energy high
enough, when the string loop can overcome the gravitational attraction
and escape to infinity. We demonstrate that string loops can be
scattered near the black hole horizon, and the energy of string
oscillations can be efficiently converted to the energy of their linear
motion. Such a transmutation effect can potentially represent
acceleration of jets in active galactic nuclei and microquasars. We give
the conditions limiting energy available for conversion onto the jetlike
motion. Surprisingly, we are able to show that string loops starting
from rest can be accelerated up to velocities ṽc even in the field of
Schwarzschild black holes, if their angular momentum parameter is low
enough. Such loops could serve as an explanation of highly relativistic
jets observed in some quasars and active galactic nuclei. The cosmic
repulsion becomes important behind the so-called static radius where it
accelerates the linear motion of the string loops up to velocity v=c
that is reached at the cosmic horizon of the Schwarzschild-de Sitter
spacetimes independently of the angular momentum parameter of the
strings.
Authors:
Stuchlík, Z.; Kološ, M.;