Particle acceleration and radiation friction effects in the filamentation instability of pair plasmas

TL;DR

This study uses particle-in-cell simulations to analyze how radiation friction influences the filamentation instability in pair plasmas, revealing effects on particle spectra without altering the instability's overall dynamics.

Contribution

It introduces the first detailed analysis of radiation friction effects on filamentation instability in pair plasmas using PIC simulations.

Findings

Magnetic field and current density grow exponentially before reaching a nonlinear phase.

Particle energy spectra broaden and develop a peak at twice the initial energy.

Radiative losses modify particle spectra but do not affect the instability's overall evolution.

Abstract

The evolution of the filamentation instability produced by two counter-streaming pair plasmas is studied with particle-in-cell (PIC) simulations in both one (1D) and two (2D) spatial dimensions. Radiation friction effects on particles are taken into account. After an exponential growth of both the magnetic field and the current density, a nonlinear quasi-stationary phase sets up characterized by filaments of opposite currents. During the nonlinear stage, a strong broadening of the particle energy spectrum occurs accompanied by the formation of a peak at twice their initial energy. A simple theory of the peak formation is presented. The presence of radiative losses does not change the dynamics of the instability but affects the structure of the particle spectra.