Acceleration of electric current-carrying string loop near a Schwarzschild black hole immersed in an asymptotically uniform magnetic field

Abstract

We study the acceleration of an electric current-carrying and axially-symmetric string loop initially oscillating in the vicinity of a Schwarzschild black hole embedded in an external asymptotically uniform magnetic field. The plane of the string loop is orthogonal to the magnetic field lines and the acceleration of the string loop occurs due to the transmutation effect turning in the deep gravitational field the internal energy of the oscillating strings to the energy of their translational motion along the axis given by the symmetry of the black hole spacetime and the magnetic field. We restrict our attention to the motion of string loop with energy high enough, when it can overcome the gravitational attraction and escape to infinity. We demonstrate that for the current-carrying string loop the transmutation effect is enhanced by the contribution of the interaction between the electric current of the string loop and the external magnetic field and we give conditions that have to be fulfilled for an efficient acceleration. The Schwarzschild black hole combined with the strong external magnetic field can accelerate the current-carrying string loop up to the velocities close to the speed of light v ∼ c. Therefore, the string loop transmutation effect can potentially well serve as an explanation for acceleration of highly relativistic jets observed in microquasars and active galactic nuclei.

Magnetized Kerr-Taub-NUT spacetime and Kerr/CFT correspondence

“…Therefore, it can be understood why this solution is still worth further investigations, for example in its relation to the Meisner effect [19] and the Kerr/CFT holography [20,21]. Some other aspects of magnetized black holes can be found in literature [17,22,23,24,25,26,27,28,29,30,31] The Kerr/CFT correspondence has been used as a tool to compute the entropy of extremal Kerr black hole using some two dimensional conformal field theory (CFT 2 ) point of views [32,33,34]. The SL (2, R) × U (1) isometry of the near horizon geometry of the extremal black hole is the window where the CFT 2 method can apply.…”

Charged string loops in Reissner–Nordström black hole background

“…While particle can move only in the central plane, taken to be equatorial plane for simplicity, and particle motion remain regular, the string loop can move also outside the equatorial plane, and string loop dynamics is generally chaotic. In Hamiltonian (31) we clearly see radial Coulombic force ∼ ΩQ/r 2 , acting on the element of string loop with electric charge Ω; Coulombic force is attractive for ΩQ < 0, and repulsive for ΩQ > 0. The radial force field breaks the symmetry of the string loop translation along the z axis, and the string loop dynamics can not be regular even in the flat spacetime.…”

Magnetized Taub-NUT spacetime

“…This can be understood since the transformed spacetime is now filled by some homogeneous magnetic field up to infinity. Various aspects of black holes immersed in external magnetic field had been studied extensively in literature [9,10,11,12,13,14,15,16,17,18,19,20,21,22].…”