Related papers: Particle acceleration driven by null electromagnet…
Recently, Ban\~{a}dos, Silk and West (BSW) found that the center-of-mass energy of two colliding test particles in the neighborhood of an extreme Kerr black hole could be arbitrarily high when one particle has the critical angular momentum…
Long ago, Newman and Janis showed that a complex deformation $z\rightarrow z+i a$ of the Schwarzschild solution produces the Kerr solution. The underlying explanation for this relationship has remained obscure. The complex deformation has…
A simple exact solution of the Einstein - Maxwell field equations for charged non-rotating black hole accelerated by an external electric field is presented. The background space-time, described by the well known Bertotti-Robinson solution,…
When a relativistically intense p-polarized laser pulse is grazingly incident onto a planar solid-state target, a slightly superluminal field structure is formed near the target surface due to the incident and reflected waves superposition.…
We study the magnetic Rayleigh-Taylor instability in relativistic collisionless plasma, as an astrophysical process for nonthermal particle acceleration. We consider dense plasma on top of a highly magnetized cavity with sheared magnetic…
In General Relativity, there is a new field of activity concerning the study of charged stars. In a recent paper, Ray et al. have shown the possibility that the collapse of a charged star could form a charged black hole before all the…
In the inner regions of an accretion disk around a black hole, the presence of non-thermal protons would via p-p collisions produce electrons, positrons and $\gamma$-rays. For such a scenario, the steady state electron-positron distribution…
In this paper we follow a new approach for particle creation by a localized strong gravitational field. The approach is based on a definition of the physical vacuum drawn from Heisenberg uncertainty principle. Using the fact that the…
The ability of a plasma surrounding spinning black holes to extract rotational energy and power energetic emissions has been recognized as a key astrophysical phenomenon. Important insights into the nature of this process are obtained…
We analyze scenarios of particle collisions in the metric of a nonextremal black hole that can potentially lead to ultrahigh energy $E_{c.m.}$ in their centre of mass frame. Particle 1 comes from infinity to the black hole horizon while…
The equilibrium configurations between a Schwarzschild black hole and a hyperextreme Kerr object are shown to be described by a three-parameter subfamily of the extended double-Kerr solution. For this subfamily, its Ernst potential and…
It has been shown that ultraenergetic collisions can occur near the horizon of an extremal Kerr black hole. Previous studies mainly focused on geodesic motions of particles. In this paper, we consider spinning test particles whose orbits…
It is well known that some black holes can act as accelerators for particles without spin. Recently, there are some works considering collision of two spinning particles in the background of Schwarzschild and Kerr black holes and it was…
It is well known that supermassive black holes in the centers of galaxies are capable of accelerating charged particles to very high energies. In many cases, the particle acceleration by black holes occurs electromagnetically through an…
With mass ratio larger than $\sim 5$ (which depends on the black hole spin and the star radius), star disruption is not expected for a black hole merging with a neutron star during the final plunge phase. In the late inspiral stage, the…
Black holes described by the Kerr metric can have a theoretical maximum dimensionless spin parameter of $a_\bullet = 1$, but several effects may limit the maximum spin parameter in astrophysical systems. We perform general relativistic…
We consider a head-on collision of two massive particles that move in the equatorial plane of an extremal Kerr black hole, which results in the production of two massless particles. Focusing on a typical case, where both of the colliding…
We develop a theory of particle acceleration inside relativistic rotating electron-positron force-free jets with spiral magnetic fields. We considered perturbation of the stationary magnetic field structure and found that acceleration takes…
We investigate how dark energy affects atom-field interaction. To this end, we consider acceleration radiation of a freely falling atom close to a Schwarzschild black hole (BH) in the presence of dark energy characterized by a positive…
We study properties of particles with zero or negative energy and a nonzero orbital angular momentum in the ergosphere of a rotating black hole. We show that the sign of the particle energy is uniquely determined by the angular velocity of…