Abstract
The Langmuir–Landau-Centrifugal Drive (LLCD), which 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 1045−46 erg/s can be heated up to 106−10 K.
Highlights
Rotating magnetospheres, with relatively strong magnetic fields, surrounding active galactic nuclei (AGN), are believed to be the regions where cosmic rays might originate [1,2].These particles are highly relativistic and one of the open problems in modern astrophysics is how do they attain such high energies.Several mechanisms have been suggested to explain acceleration of leptons or hadrons to ultra-high energies
In the so-called Fermi class of processes [3,4,5], the acceleration occurs in relatively strong magnetic fields in the magnetospheres of astrophysical objects
In the study of the role of Langmuir-Landau-Centrifugal Drive (LLCD) in the AGN magnetospheres [2], and SgrA? [7], we found that the parametrically amplified Langmuir waves, before undergoing standard Landau damp, go through another intermediate boosting via Langmuir collapse
Summary
With relatively strong magnetic fields, surrounding active galactic nuclei (AGN), are believed to be the regions where cosmic rays might originate [1,2]. The first step in the LLCD process is the parametric excitation of Langmuir waves through charge separation caused by differential rotation of different charge species (electrons and protons ) endowed with different Lorentz factors This process, examined for millisecond pulsars [12] and AGN [13], proves to be very effective in pumping enormous energy (from rotation, which in turn is gravitationally driven) into what could be called centrifugally driven electrostatic waves. The termination by means of the Landau damping of the collapse process has been numerically studied by [17] This last stage is the most important one in energy pumping process, because the whole energy of Langmuir waves transfers to particle kinetic energies. The paper is organized as follows: in Section 2, the essential formulation of LLCD is recalled, in Section 3, the theoretical model is applied to AGN heating problem, and in Section 4, our principal results are summarized
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