2021/09/30 by Filip Hejda, José P. S. Lemos, О. Б. Заславский +1 · 1 citation
Physics and Astronomy · #Angular momentum #Astrophysical Phenomena and Observations #Astrophysics and Cosmic Phenomena #Black hole (networking) #Charge (physics) #Charged black hole #Classical mechanics #Electric field #Extremal black hole #Geometry #Horizon #Limiting #Particle (ecology) #Penrose process #Physics #Plane (geometry) #Pulsars and Gravitational Waves Research #Quantum electrodynamics #Quantum mechanics #Rotating black hole #Spacetime #astro-ph.HE #gr-qc #hep-th
paper · pdf · doi:10.1103/physrevd.105.024014
published as Phys. Rev. D 105, 024014 (2022) · 25 pages, 2 tables, 1 figure
openalex created_date 2021/09/27 · openalex publication_date 2022/01/04 · arxiv created 2022/02/27 · arxiv updated 2022/03/02 · openalex updated_date 2026/08/05
The collisional Penrose process received much attention when Banados, Silk and West (BSW) pointed out the possibility of test-particle collisions with arbitrarily high center-of-mass energy in the vicinity of the horizon of an extremally rotating black hole. However, the energy that can be extracted from the black hole in this promising, if simplified, scenario, called the BSW effect, turned out to be subject to unconditional upper bounds. And although such bounds were not found for the electrostatic variant of the process, this version is also astrophysically unfeasible, since it requires a maximally charged black hole. In order to deal with these deficiencies, we revisit the unified version of the BSW effect concerning collisions of charged particles in the equatorial plane of a rotating electrovacuum black hole spacetime. Performing a general analysis of energy extraction through this process, we explain in detail how the seemingly incompatible limiting cases arise. Furthermore, we demonstrate that the unconditional upper bounds on the extracted energy are absent for arbitrarily small values of the black hole electric charge. Therefore, our setup represents an intriguing simplified model for possible highly energetic processes happening around astrophysical black holes, which may spin fast but can have only a tiny electric charge induced via interaction with an external magnetic field.