Effects of tidal charge on Blandford-Znajek process around braneworld black holes

TL;DR

This study investigates how tidal charge in braneworld black holes influences the Blandford-Znajek process, revealing that positive tidal charge decreases and negative tidal charge increases energy extraction efficiency.

Contribution

It provides the first analysis of tidal charge effects on the BZ process in braneworld black holes, quantifying the impact on power and angular momentum extraction.

Findings

Positive tidal charge reduces BZ power by up to 15.2%.

Negative tidal charge enhances BZ power by up to 66.5%.

The trend is similar for angular momentum extraction rates.

Abstract

The Blandford-Znajek (BZ) process is a pivotal mechanism to efficiently extract the energy from a rotating black hole (BH) via its plasma-filled magnetosphere in relativistic astrophysics. Within the framework of extended BZ monopole expansion, we have studied BZ process in the Randall-Sundrum braneworld BH spacetime and analyzed effects of the tidal charge on the energy and angular momentum extraction rates. It is found that the positive tidal charge reduces the BZ power of a braneworld BH, while the negative tidal charge enhances the power. Compared with a Kerr BH of the same mass and angular velocity, the BZ power exhibits a maximum reduction of approximately $15.2\%$ in positive cases, whereas in negative cases, it achieves a maximum enhancement of $66.5\%$ in power output. A similar qualitative trend is also observed for the relative angular momentum extraction rate, albeit with different magnitudes.