Generation of Ultrabrilliant Positron Beam via Superponderomotive Injection in Laser Wakefield Acceleration

TL;DR

This paper introduces a novel superponderomotive injection technique in laser wakefield acceleration that efficiently generates ultrabright positron beams with high charge and brightness, promising advancements in collider technology and laboratory astrophysics.

Contribution

The paper presents a new superponderomotive injection method for positrons in laser wakefield acceleration, enabling the production of high-brightness positron beams with practical experimental setups.

Findings

Demonstrates multi-cycle positron beams with hundreds of pC charge.

Achieves brightness of $10^{13}~ m{Am}^{-2}$ in generated positron beams.

Proposes a collisional setup compatible with current laser-plasma experiments.

Abstract

Plasma-based acceleration of positrons attracts extensive interests due to the ultrahigh accelerating gradient and ultrashort duration, while generating wakefield positron beam by the inherent injection is still a great challenge. Here, we put forward a superponderomotive injection method of positrons in the blowout regime of laser wakefield acceleration. In this method, transverse laser fields facilitate the trapping of positrons into the laser-modulated longitudinal wakefield which dominates the subsequent energy gaining, that is distinct from the electrostatic induced superponderomotive electrons. Particle-in-cell simulations demonstrate that this method can be implemented by the collision between a donut wake and a pair jet, resulting in the multi-cycle positron beam with hundreds of pC charge and brightness of $10^{13}~\rm{Am}^{-2}$. Such a collisional setup is available in the current laser-plasma experiments, and the generated positron beam is favorable for developing next generation of electron-positron collider, modeling the laboratory astrophysics and performing the ultrafast material diagnostics research.