# Polarized light from the transportation of a matter-antimatter beam in a plasma

## TL;DR

This study shows that a relativistic electron-positron beam in a magnetized plasma produces polarized synchrotron radiation, with polarization degrees depending on plasma conditions, providing insights into gamma-ray burst observations.

## Contribution

It reveals how polarized radiation arises from pair beams in plasma and links circular polarization to energy dissipation during filamentation instability.

## Key findings

- Maximum circular polarization of ~18% observed.
- Circular polarization linked to asymmetric energy dissipation.
- Polarization depends on beam-to-background plasma density ratio.

## Abstract

A relativistic electron-positron beam propagating through a magnetized electron-ion plasma is shown to generate both circularly and linearly polarized synchrotron radiation. The degrees of circular and linear polarizations depend both on the density ratio of pair beam to background plasma and initial magnetization, and a maximum degree of circular polarization $\langle P_\textrm{circ}\rangle \approx 18\%$ is found to occur for a tenuous pair beam. We demonstrate that the generation of circularly polarized radiation is intrinsically linked to asymmetric energy dissipation of the pair beam during the filamentation instability dynamics in the electron-ion plasma. These results can help in understanding the recent observations of circularly polarized radiation from gamma-ray-bursts.