Extraction of energy from an extremal rotating electrovacuum black hole: Particle collisions in the equatorial plane

Abstract

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.

25 pages, 2 tables, 1 figure

References in corpus (7)

• Acceleration of particles by nonrotating charged black holes
• Collisional Penrose process near the horizon of extreme Kerr black holes
• Collision of two general geodesic particles around a Kerr black hole
• Revised upper limit to energy extraction from a Kerr black hole
• Black holes as particle accelerators: a brief review
• The Collisional Penrose Process
• Maximum efficiency of the collisional Penrose process

Cited by in corpus (6)

• Energy extraction from Janis-Newman-Winicour naked singularity
• Penrose process in Reissner-Nordström-AdS black hole spacetimes: Black hole energy factories and black hole bombs
• Penrose and super-Penrose energy extraction from a Reissner-Nordström black hole spacetime with a cosmological constant through the BSW mechanism: Full story
• Notes on extraction of energy from an extremal Kerr-Newman black hole via charged particle collisions
• Decay of charged particles near naked singularities and super-Penrose process without fine-tuning
• Energy extraction from electrovacuum black holes via production of pairs of oppositely charged particles