Related papers: Magnetic Reconnection and Energy Extraction from a…
We revisit the Blandford & Znajek (1977) process and solve the fundamental equation that governs the structure of the steady-state force-free magnetosphere around a Kerr black hole. The solution depends on the distributions of the magnetic…
We study force-free magnetospheres in the Blandford-Znajek process from rapidly rotating black holes by adopting the near-horizon geometry of near-extreme Kerr black holes (near-NHEK). It is shown that the Znajek regularity condition on the…
The mass--energy formula of black holes implies that up to 50% of the energy can be extracted from a static black hole. Such a result is reexamined using the recently established analytic formulas for the collapse of a shell and expression…
The energy extraction from an electrostatic black hole by the decay or splitting of electrically charged particles is analyzed. We determine the energetic conditions that make the extraction process viable and present a general expression…
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…
In the MHD description of plasma phenomena the concept of magnetic field lines frozen into the plasma turns out to be very useful. We present here a method of introducing Lagrangian coordinates into relativistic MHD equations in general…
High-energy astrophysical sources such as active galactic nuclei, quasars, X-ray binaries, and gamma-ray bursts are powered by mechanisms that convert gravitational or rotational energy into radiation, jets, and relativistic outflows.…
We performed numerical simulations of general relativistic magnetohydrodynamics with uniform resistivity to investigatethe occurrence of magnetic reconnection in a split-monopole magnetic field around a Schwarzschild black hole. We found…
The ultrarelativistic jets triggered by neutrino annihilation processes or Blandford-Znajek (BZ) mechanisms in stellar-mass black hole (BH) hyperaccretion systems are generally considered to power gamma-ray bursts (GRBs). Due to the high…
The exact mechanism by which astrophysical jets are formed is still unknown. It is believed that necessary elements are a rotating (Kerr) black hole and a magnetised accreting plasma. We model the accreting plasma as a collection of…
Magnetic reconnection is invoked as one of the primary mechanisms to produce energetic particles. We employ large-scale three-dimensional (3D) particle-in-cell simulations of reconnection in magnetically-dominated ($\sigma=10$) pair plasmas…
Supermassive black holes (SMBH) are essential for the production of jets in radio-loud active galactic nuclei (AGN). Theoretical models based on Blandford & Znajek extract the rotational energy from a Kerr black hole, which could be the…
We attempt to explain the observed radio and gamma-ray emission produced in the surrounds of black holes by employing a magnetically-dominated accretion flow (MDAF) model and fast magnetic reconnection triggered by turbulence. In earlier…
We critically assess the role of the Blandford-Znajek mechanism in the powering of outflows from accretion disk-fed black holes. We argue that there is no reason to suppose that the magnetic field threading the central spinning black hole…
Some active galactic nuclei, microquasars, and gamma ray bursts may be powered by the electromagnetic braking of a rapidly rotating black hole. We investigate this possibility via axisymmetric numerical simulations of a black hole…
A toy model for the Blandford-Znajek mechanism is investigated: a Kerr black hole with a toroidal electric current residing in a thin disk around the black hole. The toroidal electric current generates a poloidal magnetic field threading…
The Fundamental Plane (FP) of Black Hole (BH) Activity in galactic nuclei relates X-ray and radio luminosities to BH mass and accretion rate. However, there is a large scatter exhibited by the data, which motivated us for a new variable. We…
We obtain analogs of the Blandford-Znajek split monopole solution for force-free magnetospheres around a slowly rotating Kerr-AdS black hole. For small black holes, we find an analytic solution to first order in the ratio of horizon radius…
Active Galactic Nuclei are powered by accretion of matter onto a supermassive black hole (SMBH) of mass Mbh ~ 10^{5}-10^{9} Msun. The accretion process is indeed the most efficient mechanism for energy release we currently know of, with up…
The effect of mass and energy loading on the efficiency at which energy can be extracted magnetically from a Kerr black hole is explored, using a semi-analytic, ideal MHD model that incorporates plasma injection on magnetic field lines. We…