The electrostatic instability for realistic pair distributions in blazar/EBL cascades

This work revisits the electrostatic instability for blazar-induced pair beams propagating through IGM with the methods of linear analysis and PIC simulations. We study the impact of the realistic distribution function of pairs resulting from interaction of high-energy gamma-rays with the extragalac...

Full description

Saved in:
Bibliographic Details
Published in:arXiv.org 2018-03
Main Authors: Vafin, S, Rafighi, I, Pohl, M, Niemiec, J
Format: Article
Language:English
Subjects:
Background radiation
Beams (radiation)
Blazars
Cascades
Computer simulation
Distribution functions
Elastic scattering
Energy dissipation
Energy distribution
Gamma rays
Linear analysis
Parameters
Simulation
Stability
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:This work revisits the electrostatic instability for blazar-induced pair beams propagating through IGM with the methods of linear analysis and PIC simulations. We study the impact of the realistic distribution function of pairs resulting from interaction of high-energy gamma-rays with the extragalactic background light. We present analytical and numerical calculations of the linear growth rate of the instability for arbitrary orientation of wave vectors. Our results explicitly demonstrate that the finite angular spread of the beam dramatically affects the growth rate of the waves, leading to fastest growth for wave vectors quasi-parallel to the beam direction and a growth rate at oblique directions that is only by a factor of 2-4 smaller compared to the maximum. To study the non-linear beam relaxation, we performed PIC simulations that take into account a realistic wide-energy distribution of beam particles. The parameters of the simulated beam-plasma system provide an adequate physical picture that can be extrapolated to realistic blazar-induced pairs. In our simulations the beam looses only 1\% percent of its energy, and we analytically estimate that the beam would lose its total energy over about \(100\) simulation times. Analytical scaling is then used to extrapolate to the parameters of realistic blazar-induced pair beams. We find that they can dissipate their energy slightly faster by the electrostatic instability than through inverse-Compton scattering. The uncertainties arising from, e.g., details of the primary gamma-ray spectrum are too large to make firm statements for individual blazars, and an analysis based on their specific properties is required.
ISSN:2331-8422
DOI:10.48550/arxiv.1803.02990