arXiv subjects

A. M. Al Zahrani

Publications and source records attributed to A. M. Al Zahrani.

6 recordsLinked to original sources

arXiv2024

Charged Particles Capture Cross-Section by a Weakly Charged Schwarzschild Black Hole

We study the capture cross-section of charged particles by a weakly charged Schwarzschild black hole. The dependence of the maximum impact parameter for capture on the particle's energy is investigated numerically for different values of the electromagnetic coupling strength between the particle and the black hole. The capture cross-section is then calculated. We show that the capture cross-section is independent of the electromagnetic coupling for ultra-relativistic particles. The astrophysical implications of our results are discussed.

gr-qc↗

arXiv2022

Charged Particles Circular Orbits around Weakly Charged and Magnetized Kerr Black Holes

We study the circular orbits of charged particles around a weakly charged Kerr black hole immersed in a weak, axisymmetric magnetic field. Firstly, we review the circular orbits of neutral particles. We then review the circular orbits of charged particles around a weakly charged Kerr black hole and weakly magnetized Kerr black hole. The case of a weakly magnetized and charged black hole is investigated thereafter. We investigate, in particular, the effect of the electromagnetic forces on the charged particles' innermost stable circular orbits. We examine the conditions for the existence of negative-energy stable circular orbits and the possibility of the emergence of a gap or double orbit in thin accretion disks. Some of the interesting astrophysical consequences of our findings are discussed as well.

gr-qc↗

arXiv2022

Circular orbits of Charged Particles around a Weakly Charged and Magnetized Schwarzschild Black Hole

We study the circular orbits of charged particles around a weakly charged Schwarzschild black hole immersed in a weak, axisymmetric magnetic field. We start by reviewing the circular orbits of neutral particles and charged particles around only weakly charged and only weakly magnetized black holes. The case of a weakly magnetized and charged black hole is investigated then. In particular, we study the effect of the electromagnetic forces on the charged particles innermost stable circular orbits. We show that negative energy stable circular orbits are possible and that two bands of charged particles circular orbits, separated by a gap of no stable circular orbits can exist. The astrophysical aspects of our findings are discussed too.

gr-qc↗

arXiv2014

Escape of Charged Particles Moving around a Weakly Magnetized Kerr Black Hole

We study the dynamics and escape of charged particles initially orbiting a weakly magnetized Kerr black hole after they get kicked in the direction normal to the orbit. The case of neutral particles is analysed first and the escape conditions are given analytically. A general analysis of charged particles innermost stable circular orbits (ISCO)s is performed numerically. We then study the charged particles three-dimensional motion and give an effective condition for their escape. We also discuss how the black hole rotation affects the escape of charged particles and the chaoticness in their dynamics.

gr-qc↗

arXiv2013

Critical escape velocity for a charged particle moving around a weakly magnetized Schwarzschild black hole

We discuss charged particles motion in a spacetime of a weakly magnetized static non-rotating black hole. We study under which conditions a charged particle originally revolving around the black hole at a circular orbit after being kicked by another particle or photon can escape to infinity. We determine the escape velocity for particles at the innermost stable circular orbits and discuss the properties of particles moving with near-critical velocity. We show that in a general case such a motion is chaotic.

gr-qc↗

arXiv2010

Particle Dynamics in Weakly Charged Extreme Kerr Throat

We study dynamics of a test charged particle moving in a weakly charged extreme Kerr throat. Dynamical equations of the particle motion are solved in quadratures. We show explicitly that the Killing tensor of the Kerr spacetime becomes reducible in the extreme Kerr throat geometry. Special types of motion of particles and light are discussed.

gr-qc↗