Energy Extraction from Black Holes

TL;DR

This paper introduces the electromagnetic Blandford-Znajek process for extracting rotational energy from black holes and discusses the formation of relativistic jets, supported by theoretical derivations and recent numerical simulations.

Contribution

It provides a detailed derivation of the Blandford-Znajek process using Kerr-Schild coordinates and summarizes recent simulation results on jet formation.

Findings

Derivation of Blandford-Znajek energy extraction mechanism

Simulation evidence of collimated relativistic jets

Insights into black hole magnetosphere electrodynamics

Abstract

In this lecture I give an introduction to the rotational energy extraction of black holes by the electromagnetic Blandford-Znajek process and the generation of relativistic jets. After some basic material on the electrodynamics of black hole magnetospheres, we derive the most important results of Blandford and Znajek by making use of Kerr-Schild coordinates, which are regular on the horizon. In a final part we briefly describe results of recent numerical simulations of accretion flows on rotating black holes, the resulting large-scale outflows, and the formation of collimated relativistic jets with high Lorentz factors.