Related papers: Extracting black-hole rotational energy: The gener…
In the Penrose process and the Blandford-Znajek mechanism, the rotational energy of a black hole (BH) is extracted via particle fission and magnetic tension, respectively. Recently, inspired by a fundamental trait in plasma astrophysics…
We consider collision of two particles that move in the equatorial plane near a general stationary rotating axially symmetric extremal black hole. One of particles is critical (with fine-tuned parameters) and moves in the outward direction.…
We consider generic axially symmetric rotating spacetimes and examine particle collisions in the ergoregion. The results are generic and agree with those obtained in the particular case of the rotating Teo wormhole in N. Tsukamoto and C.…
The mass-energy formula for a black hole endowed with electromagnetic structure (EMBH) is clarified for the nonrotating case. The irreducible mass $M_{\mathrm{irr}}$ is found to be independent of the electromagnetic field and explicitly…
The classical Penrose inequality, a relation between the ADM mass and the area of any cross section of the black hole event horizon, was introduced as a test of the weak cosmic censorship conjecture: if it fails, the trapped surface is not…
The Penrose inequality estimates the lower bound of the mass of a black hole in terms of the area of its horizon. This bound is relatively loose for extremal or near extremal black holes. We propose a new Penrose-like inequality for static…
Finite-time thermodynamics provides the means to revisit ideal thermodynamic equilibrium processes in the light of reality and investigate the energetic "price of haste", i.e. the consequences of carrying out a process in finite time, when…
In this work, we study the emission of tensor-type gravitational degrees of freedom from a higher-dimensional, simply rotating black hole in the bulk. The decoupled radial part of the corresponding field equation is first solved…
In general, when a black hole evaporates, there arises a net energy flow from black hole into its outside environment due to Hawking radiation and energy accretion onto black hole. The existence of energy flow means that the thermodynamic…
An energy $E=\omega J$ is derived for gravitational spin-orbit coupling by frame-dragging $\omega$ acting on angular momentum $J$. This interaction defines a no-boundary mechanism for linear acceleration of magnetized matter along the axis…
We investigate the possibility that gamma-ray bursts are powered by a central engine consisting of a black hole with an external magnetic field anchored in a surrounding disk or torus. The energy source is then the rotation of the black…
The stationary, spherically symmetric accretion of dark energy onto a Schwarzschild black hole is considered in terms of relativistic hydrodynamics. The approximation of an ideal fluid is used to model the dark energy. General expressions…
The particle dynamics and the electric Penrose process for the five-dimensional weakly charged Schwarzschild black hole are studied. Firstly, the horizon structure and the effective potential for the test particle are explored. The radial…
Numerous variations have been proposed on the original suggestion by Blandford and Znajek that magnetic fields could be used to extract rotational energy from black holes. A new categorization of these variations is proposed so that they…
We study the metric backreaction of mass and angular momentum accretion on black holes. We first develop the formalism of monopole and dipole linear gravitational perturbations around the Schwarzschild black holes in the…
In this paper we report the results of axisymmetric relativistic MHD simulations for the problem of Kerr black hole immersed into a rarefied plasma with ''uniform'' magnetic field. The long term solution shows properties which are…
We study physical processes around a rotating black hole in pure Gauss-Bonnet (GB) gravity. In pure GB gravity, gravitational potential has slower fall off as compared to the corresponding Einstein potential in the same dimension. It is…
In this Letter, we wish to point out that the distinguishing feature of Magnetic Penrose process (MPP) is its super high efficiency exceeding $100\%$ (which was established in mid 1980s for discrete particle accretion) of extraction of…
We show that effects similar to those for a rotating black hole arise for an observer using a uniformly rotating reference frame in a flat space-time: a surface appears such that no body can be stationary beyond this surface, while the…
The center-of-mass energy of two particles colliding near the horizon of a maximally rotating black hole can be arbitrarily high if the angular momentum of either of the incident particles is fine-tuned, which we call a critical particle.…