Effects of tidal charge on magnetic reconnection and energy extraction from spinning braneworld black hole

Abstract

Recent study shows that the magnetic reconnection can serve as an efficient mechanism to extract energy from rapidly spinning black holes. In this paper, we consider the effects of the tidal charge on the energy extraction via the magnetic reconnection in the backgrounds of a spinning braneworld black hole. With the increase of the tidal charge, we find that both the energies of the accelerated plasma and decelerated plasma decrease for the observer located at infinity. To achieve the purpose extracting the net energy from the black hole, the decelerated plasma should take negative energy. Then we observe that the power of the energy extraction via the magnetic reconnection grows with the tidal charge. Meanwhile, the efficiency also increases with the tidal charge indicating that the spinning braneworld black hole with positive tidal charge is more efficient than the Kerr black hole. Compared with the Blandford-Znajek mechanism, the magnetic reconnection process shall have a higher power for positive tidal charge. These results indicate that the tidal charge has a significant effect on the energy extraction via the magnetic reconnection process.

Extracting energy via magnetic reconnection from Kerr-de Sitter black holes

“…As have shown in Ref. [23], the energy extraction from the magnetic reconnection prefers a small orientation angle ξ. In order to meet this requirement, we set ξ = π/12, and then study the effect of the cosmological constant Λ on the energy-at-infinity per enthalpy.…”

“…In this local rest frame, one can choose the directions such that x 1 and x 3 are parallel to the radial direction r and azimuthal direction φ, respectively. Then in the ZAMO frame, the co-rotating Keplerian velocity can be expressed as [23] vK = dx φ dx t = dx φ /dλ dx t /dλ = √ g φφ dx φ /dλ−αβ φ dx t /dλ…”

“…The result showed that the magnetic reconnection mechanism is more efficient than the Blandford-Znajek process in some parameter regions. Subsequently, the study was extended to the spinning braneworld black hole [23], non-Kerr black holes [24], with or without broken Lorentz symmetry [25], Lorentz breaking Kerr-Sen and Kiselev Black Holes [26]. All the results indicate that the tidal charge, Lorentz breaking parameter, and other black hole parameters have significant effects on the energy extraction through reconnection mechanism.…”

Extracting spinning wormhole energy via Comisso-Asenjo process

“…Moreover, we showed in ref. [24] that ϵ ∞ − is negative for small orientation angle, while positive for large orientation angle leading to the violation of the condition (3.13). Therefore, we take ξ < π/6 by following ref.…”

“…The result indicates that it is feasible only for a rapidly spinning Kerr black hole. Furthermore, some other relevant studies have attempted to deal with the issue in various black hole models via such Comisso-Asenjo (CA) mechanism [24][25][26][27][28][29][30].…”