Extracting the energy and angular momentum of a Kerr black hole

• Published in: The European physical journal. C, Particles and fields Vol. 83; no. 10; pp. 960 - 7
• Main Authors: Rueda, J. A., Ruffini, R.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 24.10.2023; Springer Nature B.V; SpringerOpen
• Subjects: Active galactic nuclei; Angular momentum; Astronomy; Astrophysics and Cosmology; Electric fields; Electron spin; Electrons; Elementary Particles; Energy; Gamma ray bursts; Hadrons; Heavy Ions; Magnetic fields; Measurement Science and Instrumentation; Nuclear Energy; Nuclear Physics; Physics; Physics and Astronomy; Protons; Quantum Field Theories; Quantum Field Theory; Regular Article - Theoretical Physics; Rotation; String Theory
• ISSN: 1434-6052; 1434-6044; 1434-6052
• DOI: 10.1140/epjc/s10052-023-12153-y

It has been thought for decades that rotating black holes (BHs) power the energetic gamma-ray bursts (GRBs) and active galactic nuclei (AGNs), but the mechanism that extracts the BH energy has remained elusive. We here show that the solution to this problem arises when the BH is immersed in an external magnetic field and ionized low-density matter. For a magnetic field parallel to the BH spin, the induced electric field accelerates electrons outward and protons inward in a conical region, centered on the BH rotation axis, and of semi-aperture angle θ ≈ 60 ∘ from the BH rotation axis. For an antiparallel magnetic field, protons and electrons exchange their roles. The particles that are accelerated outward radiate off energy and angular momentum to infinity. The BH powers the process by reducing its energy and angular momentum by capturing polar protons and equatorial electrons with net negative energy and angular momentum. The electric potential allows for negative energy states outside the BH ergosphere, so the latter does not play any role in this electrodynamical BH energy extraction process.