Coupling and Acceleration of Externally Injected Electron Beams in Laser-Driven Plasma Wakefields

TL;DR

This paper explores how external electron beams can be effectively injected and accelerated in multi-stage laser wakefield accelerators, analyzing physical processes and key parameters through simulations to improve beam quality and accelerator design.

Contribution

It offers a detailed investigation of external beam injection and acceleration in multi-stage LWFA, highlighting the effects of off-axis injection and identifying parameters critical for optimizing beam quality.

Findings

Injection parameters significantly affect beam charge and quality.

Off-axis injection influences acceleration efficiency and beam divergence.

Identified key factors for optimizing multi-stage LWFA performance.

Abstract

The multi-stage method of laser wakefield acceleration (LWFA) presents a promising approach for developing stable, full-optical, high-energy electron accelerators. By segmenting the acceleration process into several booster stages, each powered by independent laser drivers, this technique effectively mitigates challenges such as electron dephasing, pump depletion, and laser diffraction. A critical aspect of multi-stage LWFA is the nonlinear interaction between the injected electron beam and the laser-driven wakefields in the booster stage. This study investigates the injection and acceleration of external electron beams within wakefields in the booster stage using multi-dimensional Particle-In-Cell (PIC) simulations. We provide both qualitative and quantitative descriptions of the observed physical processes. Key parameters influencing charge coupling process and the resultant beam quality have been identified. Furthermore, we have examined how off-axis injection relative to the driver laser influences the acceleration process and beam quality. Our findings provide valuable insights for advancing and optimizing multi-stage plasma-based accelerators.