Generation of Ultra-Collimated Polarized Attosecond $\gamma-$Rays via Beam Instabilities

TL;DR

This paper introduces a novel method to generate ultra-collimated, polarized attosecond gamma-ray pulses by exploiting beam instabilities during electron-plasma interactions, offering a feasible source for advanced nuclear and high-energy physics applications.

Contribution

It demonstrates that beam instabilities can be harnessed to produce polarized gamma-ray attosecond pulses from unpolarized electron beams interacting with solid-density plasma, challenging previous assumptions.

Findings

Generation of polarized gamma-ray slices via nonlinear Compton scattering.

High-quality electron microbunches suitable for free-electron lasers.

Polarization achieved through symmetry-breaking caused by hosing instability.

Abstract

Polarized attosecond $\gamma-$rays may offer excitation and hyperfine tracking of reactions relevant to nuclear physics, astrophysics, high-energy physics, etc. However, unfortunately, generation of a feasible and easy-to-deploy source is still a great challenge. Here, we put forward a novel method for producing ultra-collimated high-brilliance polarized attosecond $\gamma-$rays via the interaction of an unpolarized electron beam with a solid-density plasma. As a relativistic electron beam enters a solid-density plasma, it can be modulated into high-density clusters via the self-modulation instability of itself and further into attosecond slices due to its own hosing instability. This is accompanied by the generation of similar pulse-width $\gamma-$slices via nonlinear Compton scattering. The severe hosing instability breaks the symmetry of the excited electromagnetic fields, resulting in net linear polarization of $\gamma-$slices, which challenges the conventional perception that the interaction of an axially symmetric unpolarized electron beam with a uniform plasma cannot generate polarized radiation. In addition, we also obtain high-quality electron microbunches which may serve as an alternative source for prebunched free-electron lasers.