On the heating of AGN magnetospheres

TL;DR

This paper investigates how the Langmuir-Landau-Centrifugal Drive (LLCD) mechanism can convert gravitational energy into heat in AGN magnetospheres, potentially explaining their extreme thermal luminosity and heating up to millions of Kelvin.

Contribution

It introduces a detailed analysis of the LLCD process in AGN magnetospheres, highlighting the stages of energy transfer and heating, with estimates of temperature increases.

Findings

Energy transfer from rotation to electrostatic modes is efficient.

Langmuir collapse amplifies energy pumping.

Magnetospheres can reach temperatures of 10^6 to 10^10 K.

Abstract

The Langmuir-Landau-Centrifugal Drive (LLCD), that can effectively "convert" gravitational energy into particles, is explored as a driving mechanism responsible for the extreme thermal luminosity acquired by some active galactic nuclei (AGN). For this purpose we consider equations governing the process of heating of AGN magnetospheres. In particular, we examine the Fourier components of the momentum equation, the continuity equation and the Poisson equation in the linear approximation and estimate the growth rate of the centrifugally excited electrostatic waves and the increment of the Langmuir collapse. It is shown that the process of energy pumping is composed of three stages: in the first stage the energy is efficiently transferred from rotation to the electrostatic modes. In due course of time, the second regime - the Langmuir collapse - occurs, when energy pumping is even more efficient. This process is terminated by the Landau damping, when enormous energy is released in the form of heat. We show that the magnetospheres of the supermassive black holes with luminosities of the order of $10^{45-46}$erg/s can be heated up to $10^{6-10}$K.