The Mechanisms Of Extracting Energy From Rotating Black Holes And Its Application In Astrophysics

Two types of mechanisms of extracting energy from a rotating black hole (BH) are investigated in this paper: the Blandford-Znajek (BZ) process and magnetic coupling (MC) process. And we discussed the coexistence model of the BZ and MC process as well as several applications of the model in high-energy astrophysics. The main results are summarized as follows.Firstly, the unified analytical expressions for the powers and torques in the BZ and MC processes are derived based an improved equivalent circuit, and the condition for the coexistence of the BZ process and the MC process are discussed. In addition, the powers for extracting energy by the two mechanisms are compared briefly.Secondly, we discuss several interesting applications of the coexistence model in astrophysics. Based on this model we fit the jet powers and the frequencies of the high frequency quasi-periodic oscillations (HFQPO) respectively, which are observed in some BH X-ray binaries. It is shown that the BH spins rapidly in the same direction with the accretion disk, and the spins are constrained in a rather narrow range. It also implies a possible way to detect the black hole spin.Thirdly, we introduce three types of black hole systems with different scales: stellar-mass BH, super-massive BH and intermediate-mass BH. Furthermore, their similar characteristics, such as jets, QPOs and very steep emission are discussed in detail. These result demonstrate that the relations among the magnetic field at the BH horizon, the accretion rate of the disk and the BH mass in quasar are analogous to the corresponding relations in microquasar.Finally, we summarize the main results and point out the limitation of our model. In addition, we propose a scheme to improve our model in the future work.