Item

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.