Deciphering in situ electron dynamics of ultrarelativistic plasma via polarization pattern of emitted γ -photons

Abstract

Understanding and interpretation of the dynamics of ultrarelativistic plasma is a challenge, which calls for the development of methods for in situ probing the plasma dynamical characteristics. We put forward a new method, harnessing polarization properties of γ-photons emitted from a non-prepolarized plasma irradiated by a circularly polarized pulse. We show that the angular pattern of γ-photon linear polarization is explicitly correlated with the dynamics of the radiating electrons, which provides information on the laser-plasma interaction regime. Furthermore, with the γ-photon circular polarization originating from the electron radiative spin flips, the plasma susceptibility to quantum electrodynamical processes is gauged. Our study demonstrates that the polarization signal of emitted γ-photons can be a versatile information source, which would be beneficial for the research fields of laser-driven plasma, accelerator science, and laboratory astrophysics.Received 27 October 2021Revised 15 February 2022Accepted 11 April 2022DOI:https://doi.org/10.1103/PhysRevResearch.4.L022024Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Open access publication funded by the Max Planck Society.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasBeam polarizationGamma-ray generation in plasmasHigh intensity laser-plasma interactionsLaboratory studies of space & astrophysical plasmasLaser-plasma interactionsPolarization in interactions & scatteringUltrashort pulsesPhysical SystemsRelativistic plasmasAccelerators & BeamsPlasma Physics