We demonstrate an extraordinary effect of energy gain by a single radiating charged particle inside the ergosphere of a Kerr black hole in presence of magnetic field. We solve numerically the covariant form of the Lorentz-Dirac equation reduced from the DeWitt-Brehme equation and analyze energy evolution of the radiating charged particle inside the ergosphere, where the energy of emitted radiation can be negative with respect to a distant observer in dependence on the relative orientation of the magnetic field, black hole spin and the direction of the charged particle motion. Consequently, the charged particle can leave the ergosphere with energy greater than initial in expense of black hole's rotational energy. In contrast to the original Penrose process and its various modification, the new process does not require the interactions (collisions or decay) with other particles and consequent restrictions on the relative velocities between fragments. We show that such a Radiative Penrose effect is potentially observable and discuss its possible relevance in formation of relativistic jets and in similar high-energy astrophysical settings.
We investigate the effect of superradiance shielding for the analogue rotating black holes simulated by optical vortices by calculating the radial motion of massless particles in such spacetime background. We add the conditions $E<LΩ_{r_{e}}$ and $L>0$ to judge the classically forbidden region of superradiance. It is found that the superradiance forbidden region exists near the static limit inside the ergosphere,which will limit the classical Penrose process for the particles with some specific energies and angular momenta. Once these particles satisfying the superradiance conditions aremeasur…
Repetitive Penrose Process in Kerr-Taub-NUT black hole spacetime
Harbin Institute of Technology（哈尔滨工业大学）；University of Tashkent for Applied Sciences（塔什干应用科学大学）；New Uzbekistan University（新乌兹别克斯坦大学）；Institute for Advanced Studies, New Uzbekistan University（新乌兹别克斯坦大学高等研究院）；Institute of Theoretical Physics, National University of Uzbekistan（乌兹别克斯坦国立大学理论物理研究所）
According to Penrose effect, particles with negative energy can exist in the ergospheres of rotating black holes. We analyze geodesics for such particles and show that there are no circular and elliptic orbits in the ergosphere of a rotating black hole. We also show that there are geodesics which begin and terminate at the singularity and present the conditions under which such geodesics do not begin and terminate at the singularity.
States of particles with negative energies are considered for the nonrelativistic and relativistic cases. In nonrelativistic case it is shown that the decays close to the attracting center can lead to the situation similar to the Penrose effect for rotating black hole when the energy of one of the fragments is larger than the energy of the initial body. This is known as the Oberth effect in the theory of the rocket movement. The realizations of the Penrose effect in the non-relativistic case in collisions near the attracting body and in the evaporation of stars from star clusters are indicated…
Analog physics allows simulating inaccessible objects, such as black holes, in the lab. We propose to implement an acoustic Kerr black hole with quantized angular momentum in a polariton Bose-Einstein condensate. We show that the metric of the condensate is equivalent to the Kerr's one, exhibiting a horizon and an ergosphere. Using topological defects as test particles, we demonstrate an analog Penrose effect, extracting the rotation energy of the black hole. The particle trajectories are well described by the time-like geodesics of the Kerr metric, confirming the potential of analog gravity.
Extracting Energy from Magnetized Rotating Black Holes in Horndeski Gravity via the Magnetic Penrose Process
School of Material Science and Engineering, Chongqing Jiaotong University（重庆交通大学材料科学与工程学院）；College of Physics and Optoelectronic Engineering, Chongqing Normal University（重庆师范大学物理与电子工程学院）
This paper explores the neutral particle motion and collisional Penrose process in ergoregion of the braneworld Kerr black hole. We analyze the properties of event horizon, ergosphere and static limit. The particle collision in ergoregion via the Penrose process is investigated. Furthermore, we study the negative energy states and show that the sign of particle energy can be uniquely determined by the sign of angular momentum. In addition, we study the Wald inequality to determine the limits of energy extraction via the Penrose process and also find lower bound of the irreducible mass. The exp…
We first study the escape probability of the spinning particle emitted from the Kerr black hole and find that the escape probability increases with the spin of the particle around the extreme Kerr black hole; in contrast, the escape probability decreases at the position near the horizon but increases at the position far away from the horizon with the increasing spin of the particle. We then probe the relation between the escape probabilities and the energy extraction efficiencies of collisional Penrose processes for the particles with varying spin. For the extreme Kerr black hole, the efficien…
Spinning black holes create electromagnetic storms when immersed in ambient magnetic fields, illuminating the otherwise epically dark terrain. In an electromagnetic extension of the Penrose process, tremendous energy can be extracted, boosting the energy of radiating particles far more efficiently than the mechanical Penrose process. We locate the regions from which energy can be mined and demonstrate explicitly that they are no longer restricted to the ergosphere. We also show that there can be toroidal regions that trap negative energy particles in orbit around the black hole. We find that t…
Rotating and non-linear magnetic-charged black hole with an anisotropic matter field
School of Physics Science and Technology, Xinjiang University（新疆大学物理科学与技术学院）；Faculty of Science, Kunming University of Science and Technology（昆明理工大学理学院）
Relying on the Penrose process mechanism, we study the possibility of energy extraction from a binary system composed of two extreme electrostatic black holes (BHs) oppositely charged, separated by a strut described by Bonnor's metric (BM). We determined and plotted the generalized ergosphere that surrounds only one of the BH. We demonstrate the existence of non closed orbits of negative energy outside the event horizon; these orbits allow the possibility of energy extraction by particle disintegration from a system described by the BM. Besides we prove that the extraction process can occur wh…
In this paper, we investigate the Penrose process in the purlieus of the axially symmetric magnetized Reissner-Nordström black hole for both neutral and charged particles. We start with the study of the geometry of the black hole and find the regions where the $g_{tt}$ component of the metric tensor is positive (i.e., $g_{tt}>0$). It is interestingly found that the condition $g_{tt}>0$ is fulfilled not only close to the event horizon known as the ergosphere but also far away from the event horizon in the silhouette of potential wells. We also show that as the dimensionless magnetic field $B$ i…
We define and sketch the generalized ergosphere of the Majumdar-Papapetrou (MP) spacetime. In particular, we demonstrate the existence of closed orbits of negative energy that live outside the event horizon of such a spacetime. Relying on the Penrose process mechanism, we use these orbits to illustrate the possibility of energy extraction from a MP binary black hole by particle scattering. We also analyze the efficiency of the process, and construct explicit examples that optimize the extraction of energy. Lastly, we show how such concepts can be extended to a pair of non-coalescing Kerr black…
We consider the decay of a particle with some energy $E_{0}>0$ inside the ergosphere of a black hole. After the first decay one of particles with the energy $E_{1}<0$ falls towards a black hole while the second one with $% E_{2}>E_{0}\,\ $moves in the outward direction. It bounces back from a reflecting shell and, afterwards, the process repeats. For radial motion of charged particles in the Reissner-Nordstöm metric, the result depends strongly on a concrete scenario. In particular, an indefinitely large growth of energy inside a shell is possible that gives rise to a black-hole bomb. We also …
Sgr A* as a Galactic PeVatron: Multimessenger Signatures of the Magnetic Penrose Process
Universidad Politécnica de Madrid（马德里理工大学）；Instituto de Física Teórica UAM-CSIC（UAM-CSIC理论物理研究所）；Universidad Autónoma de Madrid（马德里自治大学）；Escuela Politécnica Superior, Universidad San Pablo-CEU（圣保罗ceu大学高等理工学院）；Utah State University（犹他州立大学）
Binary black hole may form near a supermassive black hole. The background black hole (BH) will affect the gravitational wave (GW) generated by the binary black hole. It is well known that the Penrose process may provide extra energy due to the ergosphere. In the present paper we investigate the energy amplification of the gravitational wave by a Kerr black hole background. In particular and different from the earlier studies, we compare the energies of the waves in the cases with and without a nearby Kerr BH. We find that only when the binary black hole is moving relative to the Kerr backgroun…
We construct the light escape cones of isotropic spot sources of radiation residing in special classes of reference frames in the Kerr-de Sitter (KdS) black hole spacetimes, namely, in the fundamental class of 'non-geodesic' locally non-rotating reference frames (LNRFs), and two classes of 'geodesic' frames, the radial geodesic frames (RGFs), both falling and escaping, and the frames related to the circular geodesic orbits (CGFs). We compare the cones constructed in a given position for the LNRFs, RGFs, and CGFs. We have shown that the photons locally counter-rotating relative to LNRFs with po…
Penrose and super-Penrose energy extraction from a Reissner-Nordström black hole spacetime with a cosmological constant through the BSW mechanism: Full story
In this paper, we study the Penrose process and the maximum energy extracted from the collision of two particles near the Kerr-Newman black hole with WGC condition. We consider the collision process when two particles collide in the ergosphere region of a black hole, scattering two new particles; one of them falls into the black hole and the other escapes to infinity. Our calculations also show an increasing in the energy. We also checked how much energy could be received from a black hole for particles with different spins. Results of this paper will help us to identify and study the black ho…
We derive an exact solution of the spherically symmetric Bardeen black hole surrounded by perfect fluid dark matter (PFDM). By treating the magnetic charge $g$ and dark matter parameter $α$ as thermodynamic variables, we find that the thermodynamic first law and the corresponding Smarr formula are satisfied. The thermodynamic stability of the black hole is also studied. The result show that, there exists a critical radius $r_{+}^{C}$, where the heat capacity diverges, suggesting that the black hole is thermodynamically stable in the range $0<r_{+}<r_{+}^{C}$. In addition, the critical radius $…
In this paper, we examine the effect of dark matter to a Kerr black hole of mass $m$. The metric is derived using the Newman-Janis algorithm, where the seed metric originates from the Schwarzschild black hole surrounded by a spherical shell of dark matter with mass $M$ and thickness $Δr_{s}$. The seed metric is also described in terms of a piecewise mass function with three different conditions. Specializing in the non-trivial case where the observer resides inside the dark matter shell, we analyzed how the effective mass of the black hole environment affects the basic black hole properties. A…
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 known as magnetic reconnection (MR), a new energy extraction mechanism based on the fast reconnection of the magnetic field lines inside the ergosphere has been proposed by Comisso and Asenjo. In this paper, we investigate energy extraction caused by MR in the ergosphere of a rapidly spinning BH with broken Lorentz symmetry by a background bumblebee vector fiel…
