On the Magnetic Field Screening in Strong Crossed Electromagnetic Fields

Abstract

It has been shown that a rotating Black Hole (BH hereafter) immersed in a test background magnetic field, of initial strength $${{B}_{0}}$$ and aligned parallel to the BH rotation axis, generates an induced electric field, which strength is proportional to the background magnetic field. We consider the configuration of crossed fields: $${\mathbf{B}} = B\hat {z}$$ and $${\mathbf{E}} = E\hat {y}$$ . In this system, a huge number of $${{e}^{ + }}{{e}^{ - }}$$ pairs can be emitted and start to be accelerated to high energies, by means of the induced electric field, and emit synchrotron photons. These photons interact with the magnetic field via the magnetic pair production process (MPP hereafter), $$\gamma + B \to {{e}^{ + }} + {{e}^{ - }}$$ . The motion of all these pairs around the magnetic field lines generates also an induced magnetic field oriented in the opposite direction to the background one. This implies a reduction of the background magnetic field. The purpose of this study is to show if this reduction occurs, which implies a decreases the MPP efficiency and, consequently, the enhancement of the probability for the synchrotron photons to escape from the region and be detected.