Publication date: Jun 2018
Abstract:
Radiation reaction acting on a charged particle moving at a stable
circular orbit of a magnetized black hole (BH) can lead to the shift of
the orbital radius outward from the BH. The effect causes an increase of
the energy and angular momentum of the particle measured by an observer
at rest at infinity. In this paper, we show that „widening“ of such
orbits is independent of the field configuration, but it appears only in
the cases with the external Lorentz force acting outward from the BH.
This condition corresponds to qLB > 0, where q and L are the charge
and angular momentum of the particle, and B is intensity of the external
magnetic field. As examples of the orbital widening, we consider two
scenarios with an external homogeneous magnetic field and a magnetic
dipole field generated by a current loop around a Schwarzschild BH. We
show that the orbital widening is accompanied by quasi-harmonic
oscillations of the particle, which are considerably large in the
magnetic dipole fields. We also estimate the timescales of orbital
widening, from which it follows that the effect can be relevant in the
vicinity of stellar-mass BHs.
Authors:
Tursunov, A. A.; Kološ, M.; Stuchlík, Z.;