Blandford-Znajek (BZ) mechanism describes a process extracting rotation energy from a spinning black hole (BH) via magnetic field lines penetrating the event horizon of central BH. In this paper, we present a perturbation approach to study force-free jets launched by the BZ mechanism, and its two immediate applications: (1) we present a high-order split monopole perturbation solution to the BZ mechanism, which accurately pins down the energy extraction rate $\dot E$ and well describes the structure of BH magnetosphere for all range of BH spins ($0\leq a\leq 1$); (2) the approach yields an exact constraint for the monopole field configuration in the Kerr spacetime, $I = Ω(1-A_ϕ^2)$, where $A_ϕ$ is the $ϕ-$component of the vector potential of electromagnetic field, $Ω$ is the angular velocity of magnetic field lines and $I$ is the poloidal electric current. The constraint is of particular importance to benchmark the accuracy of numerical simulations.
Testing the Kerr-nature of stellar-mass black hole candidates by combining the continuum-fitting method and the power estimate of transient ballistic jets
Attempt to find a correlation between the spin of stellar-mass black hole candidates and the power of steady jets: relaxing the Kerr black hole hypothesis
Invariant characterization of the Kerr spacetime: Locating the horizon and measuring the mass and spin of rotating black holes using curvature invariants
Electron-positron cascade in magnetospheres of supermassive Kerr black holes and the origin of relativistic AGN jets
University of Kansas（堪萨斯大学）；Massachusetts Institute of Technology（麻省理工学院）；Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences（波兰科学院尼古拉·哥白尼天文中心）
