Energy Extraction from Rotating Charged Black Holes in Kalb-Ramond Gravity

Abstract

This work presents a comprehensive study of energy extraction via the Comisso-Asenjo magnetic reconnection mechanism from rotating charged black holes in the context of Kalb-Ramond (KR) gravity. We systematically investigate the influence of various parameters on the energy extraction process, comparing the results in two distinct regions: the circular orbit region and the plunging region. {The results reveal that the Lorentz-violating parameter has a significant impact on energy extraction, affecting not only the parameter space where energy extraction is possible, but also the energy extraction power and efficiency.} It is found that the energy extraction process in the circular orbit region can offer a promising avenue for constraining KR gravity. In contrast, although energy extraction from the plunging region remains feasible even for black holes with relatively low spins and takes place nearer to the event horizon, its sensitivity to the Lorentz-violating parameter is significantly reduced. Overall, the Comisso-Asenjo magnetic reconnection mechanism can serve as a probe of the KR field, particularly through the energy extraction process in the circular orbit region.

Figures (6)

• Figure 1: Energy extraction region in the circular orbit region for different parameter combinations. In each panel, the fixed and variable parameters are set to the following values: (a) $\ell=0.1$, $Q/M=0.1$, $\sigma=100$, $\xi = \{ 0, \pi/20, \pi/12, \pi/6 \}$; (b) $\ell=0.1$, $Q/M=0.1$, $\xi=\pi/12$, $\sigma = \{ 3, 10, 30, 100 \}$; (c) $\ell=0.1$, $\sigma=100$, $\xi=\pi/12$, $Q/M = \{ 0.1, 0.2 , 0.3, 0.4\}$; (d) $Q=0.1$, $\sigma=100$, $\xi=\pi/12$, $\ell = \{ -0.4, -0.2, 0, 0.2, 0.4 \}$.
• Figure 2: Energy extraction power per unit enthalpy density $P_{\rm extra}/w$ in the circular orbit region for different parameter combinations. The vertical dashed lines mark the position of the photon sphere. In each panel, the black hole spin is fixed as $a/M=0.9$ and the other parameters are set to the following values: (a) $\ell=0.1$, $Q/M=0.1$, $\sigma=10^4$, $\xi = \{ 0, \pi/20, \pi/12, \pi/6 \}$; (b) $\ell=0.1$, $Q/M=0.1$, $\xi=\pi/12$, $\sigma = \{ 10, 10^2, 10^3, 10^4 \}$; (c) $\ell=0.1$, $\sigma=10^4$, $\xi=\pi/12$, $Q/M = \{ 0.06, 0.12 , 0.18, 0.24 \}$; (d) $Q/M=0.1$, $\sigma=10^4$, $\xi=\pi/12$, $\ell = \{-0.10, -0.07, -0.03, 0, 0.06, 0.12 , 0.16 \}$.
• Figure 3: Energy extraction efficiency $\eta$ in the circular orbit region for different parameter combinations. The vertical dashed lines mark the position of the photon sphere. In each panel, the black hole spin is fixed as $a/M=0.9$ and the other parameters are set to the following values: (a) $\ell=0.1$, $Q/M=0.1$, $\sigma=10^4$, $\xi = \{ 0, \pi/20, \pi/12, \pi/6 \}$; (b) $\ell=0.1$, $Q/M=0.1$, $\xi=\pi/12$, $\sigma = \{ 10, 10^2, 10^3, 10^4 \}$; (c) $\ell=0.1$, $\sigma=10^4$, $\xi=\pi/12$, $Q/M = \{ 0.06, 0.12 , 0.18, 0.24 \}$; (d) $Q/M=0.1$, $\sigma=10^4$, $\xi=\pi/12$, $\ell = \{-0.10, -0.07, -0.03, 0, 0.06, 0.12 , 0.16 \}$.
• Figure 4: Energy extraction region in the plunging region for different parameter combinations. The parameter combinations are identical to those used in Fig. \ref{['CO_Region']}.
• Figure 5: Energy extraction power per unit enthalpy density $P_{\rm extra}/w$ in the plunging region for different parameter combinations. The vertical solid lines indicate the position of the event horizon. The parameter combinations are identical to those used in Fig. \ref{['CO_Power']}.