The energetics of black holes in electromagnetic fields by the penrose process

Wagh, Sanjay M.; Dadhich, Naresh

doi:10.1016/0370-1573(89)90156-7

Cited by 64 publications

(46 citation statements)

References 79 publications

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“…However, a careful analysis by [19][20][21][22] (see also [7]), showed that it is unlikely that negative energy states, necessary for the Penrose process to work, may be achieved through the particles disintegration and/or collision inside the ergosphere. This conclusion has been confirmed more recently by [23][24][25] for high energy particle collisions.…”

Section: The Mechanical Penrose Processmentioning

confidence: 99%

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Extracting black-hole rotational energy: The generalized Penrose process

et al. 2014

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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 Tµν 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 jetproducing "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.

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Section: The Mechanical Penrose Processmentioning

confidence: 99%

“…Thus, they are captured (together with the negative energy particles) by the black hole. Note that for charged particles evolving in the electromagnetic field of a Kerr-Newman black hole, the efficiency of the mechanical Penrose process can be very large [7,26].…”

Section: The Mechanical Penrose Processmentioning

confidence: 99%

Extracting black-hole rotational energy: The generalized Penrose process

et al. 2014

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“…The significance of the Blandford-Znajek mechanism of jet fuelling [41,263] for the active galactic nuclei and X-ray binaries is still under discussion [258,122,198,185] (while it is rather generally accepted for gamma-ray bursts [186]). There also exist other extraction possibilities (see [309] for a review), mainly the Punsly-Coroniti variant of Penrose mechanism [259] (contrary to the Blandford-Znajek one, it does not require a magnetic field threading the horizon) which was indeed noticed in numerical simulations [169]. Another efficient scenario has been proposed recently [194].…”

Section: Galactic Nuclei and X-ray Binariesmentioning

confidence: 90%

Towards Gravitating Discs Around Stationary Black Holes

Semerák

2002

Gravitation: Following the Prague Inspiration

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This article outlines the search for an exact general relativistic description of the exterior (vacuum) gravitational field of a rotating spheroidal black hole surrounded by a realistic axially symmetric disc of matter. The problem of multi-body stationary spacetimes is first exposed from the perspective of the relativity theory (section 1) and astrophysics (section 2), listing the basic methods employed and results obtained. Then (in section 3) basic formulas for stationary axisymmetric solutions are summarized. Sections 4 and 5 review what we have learnt with MiroslavŽáček and Tomáš Zellerin about certain static and stationary situations recently. Concluding remarks are given in section 6. Although the survey part is quite general, the list of references cannot be complete. Our main desideratum was the informative value rather than originality -novelties have been preferred, mainly reviews and those with detailed introductions. The fields of multi-body systems involving black holesThe subject of self-gravitating sources around rotating black holes is interesting in several respects, relevant from the point of view of the relativity theory itself as well as in the astrophysical context.First, due to the non-linearity of Einstein's equations, the field of a multi-body system is a traditional challenge where one typically does not manage with a simple superposition. 1 On the first post-Newtonian level, the "celestial mechanics" of gravitationally interacting bodies can be kept linear [89,90], but in the strong-field region the interaction may bring surprising features that have only been described in a very few cases yet (for a two-body problem -today at the centre of attention because of the expected gravitational waves from colliding compact binaries, "the current state of art is the third post-Newtonian approximation" [91]).The second point in which the problem embodies the essence of general relativity is the effect of inertial frame dragging due to the rotation of the sources. Contrary to the Newtonian treatment which does not discriminate between static and stationary situation, the field is now determined not only by mass-energy configuration, but also by its motion within the bodies. The inertial space can be imagined as a viscous fluid mixed by the sources. In today's "gravitoelectromagnetic" language, gravity has not only an electric component, generated by the mass, but also a magnetic one, generated by mass currents; see [245, 103, 215, 298, 147, 79, 202, 201, 1 Even the problem of an "isolated" object is very difficult (mainly if its motion must be found as well, not mentioning the interior field) unless one makes some simple assumptions about its multipole structure; see e.g. [98,99,17] for a treatment of bodies with matter interior, [297] for that also valid for singular bodies such as black holes, and [40] for the case of point-like particles.

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“…Off-equatorial motion of charged particles in background gravitational and electromagnetic fields has been studied in papers [17,18]. Detailed analysis of the astrophysics of rotating black holes in the presence of electromagnetic fields in connection with energetic mechanisms such as the Penrose process has been discussed by Wagh and Dadhich in paper [19]. The Blandford-Znajek mechanism applied for the black hole with a toroidal electric current was investigated in papers [20,21].…”

Section: Introductionmentioning

confidence: 99%

Dynamics of an electric current-carrying string loop near a Schwarzschild black hole embedded in an external magnetic field

et al. 2013

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We study motion of an electric current-carrying string loop oscillating in the vicinity of the Schwarzschild black hole immersed in an external uniform magnetic field. The dependence of boundaries and different types of motion of the string loop on magnetic field strength is found. The dynamics of the string loop in the Cartesian xy plane depends both on value and direction of the magnetic field and current. It is shown that the magnetic field influence on the behavior of the string loop is quite significant even for weak magnetic field strength. The oscillation of the string loop becomes stronger or weaker in dependence on the direction of the Lorenz force. We illustrate the various regimes of the trajectories of the string loop that can fall down into the black hole, escape to infinity, or be trapped in the finite region near the horizon for the different representative values of the magnetic field. We have also considered the flat spacetime limit as the condition of the escape of the string loop from the neighborhood of the black hole to infinity. We found the expression for the magnetic field strength for which the oscillatory motion of the string loop totally vanishes and the string loop can have maximal acceleration in the perpendicular direction to the plane of the loop.

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The energetics of black holes in electromagnetic fields by the penrose process

Cited by 64 publications

References 79 publications

Extracting black-hole rotational energy: The generalized Penrose process

Extracting black-hole rotational energy: The generalized Penrose process

Towards Gravitating Discs Around Stationary Black Holes

Dynamics of an electric current-carrying string loop near a Schwarzschild black hole embedded in an external magnetic field

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