%0 Journal Article
%T Extracting black-hole rotational energy: The generalized Penrose process
%+ Institut d'Astrophysique de Paris (IAP)
%A Lasota, J. -P.
%A Gourgoulhon, E.
%A Abramowicz, M.
%A Tchekhovskoy, A.
%A Narayan, R.
%< avec comité de lecture
%J Physical Review D
%V 89
%8 2014
%D 2014
%Z 1310.7499
%Z 2014PhRvD..89b4041L
%R 10.1103/PhysRevD.89.024041
%K 04.70.Bw
%K 95.30.Sf
%K 95.30.Qd
%K 97.60.Lf
%K Classical black holes
%K Relativity and gravitation
%K Magnetohydrodynamics and plasmas
%K Black holes
%K General Relativity and Quantum Cosmology
%K Astrophysics - High Energy Astrophysical Phenomena
%Z Sciences of the Universe [physics]Journal articles
%X In the case involving particles, the necessary and sufficient condition for the Penrose process to extract energy from a rotating black hole is absorption of particles with negative energies and angular momenta. No torque at the black-hole horizon occurs. In this article we consider the case of arbitrary fields or matter described by an unspecified, general energy-momentum tensor T_{μν} and show that the necessary and sufficient condition for extraction of a black hole's rotational energy is analogous to that in the mechanical Penrose process: absorption of negative energy and negative angular momentum. We also show that a necessary condition for the Penrose process to occur is for the Noether current (the conserved energy-momentum density vector) to be spacelike or past directed (timelike or null) on some part of the horizon. In the particle case, our general criterion for the occurrence of a Penrose process reproduces the standard result. In the case of relativistic jet-producing "magnetically arrested disks," we show that the negative energy and angular-momentum absorption condition is obeyed when the Blandford-Znajek mechanism is at work, and hence the high energy extraction efficiency up to ∼300% found in recent numerical simulations of such accretion flows results from tapping the black hole's rotational energy through the Penrose process. We show how black-hole rotational energy extraction works in this case by describing the Penrose process in terms of the Noether current.
%G English
%2 https://insu.hal.science/insu-03645730/document
%2 https://insu.hal.science/insu-03645730/file/PhysRevD.89.024041.pdf
%L insu-03645730
%U https://insu.hal.science/insu-03645730
%~ INSU
%~ CNRS
%~ IAP
%~ SORBONNE-UNIVERSITE
%~ SU-INF-2018
%~ SU-SCIENCES
%~ SU-TI
%~ ALLIANCE-SU