Energy Enhancement and Energy Spread Compression of Electron Beams in a Hybrid Laser-Plasma Wakefield Accelerator

Ying Wu,Cheng Wang,Lintong Ke,Yu Chen,Xiaojun Yang,Rong Qi,Zhiyong Qin,Yuxin Leng,Zhizhan Xu,Ruxin Li,Ke Feng,Changhai Yu,Zhijun Zhang,Jiansheng Liu,Wentao Wang

doi:10.3390/app9122561

Abstract

We experimentally demonstrated the generation of narrow energy-spread electron beams with enhanced energy levels using a hybrid laser-plasma wakefield accelerator. An experiment featuring two-color electron beams showed that after the laser pump reached the depletion length, the laser-wakefield acceleration (LWFA) gradually evolved into the plasma-driven wakefield acceleration (PWFA), and thereafter, the PWFA dominated the electron acceleration. The energy spread of the electron beams was further improved by energy chirp compensation. Particle-in-cell simulations were performed to verify the experimental results. The generated monoenergetic high-energy electron beams are promising to upscale future accelerator systems and realize monoenergetic γ -ray sources.

Highlights

In recent decades, the quality of electron beams (e-beams) has continuously improved with the rapid development of plasma-based particle accelerators, including laser-wakefield accelerators (LWFA)and plasma-driven wakefield accelerators (PWFA), with acceleration gradients surpassing 100 GV/m [1].Monoenergetic e-beams with multi-GeV energy, low emittance, and large beam charge have been generated in many laser-wakefield acceleration (LWFA) experiments [2,3,4,5,6,7,8]
The simulations showed that after the laser pump reached the depletion length, the acceleration mode changed from LWFA to plasma-driven wakefield acceleration (PWFA) gradually, and the wakefield driven by the high-charge e-beam dominated the following electron acceleration, so the low-charge e-beam could be accelerated sustainably
When the plasma length was increased to be larger than the laser pump depletion length, one e-beam was still accelerated to 640.7 MeV with 1.1% full width at half maximum (FWHM) energy spread and the other e-beam lost its energy rapidly to 230.5 MeV with 50.3% FWHM energy spread

Summary

Introduction

The quality of electron beams (e-beams) has continuously improved with the rapid development of plasma-based particle accelerators, including laser-wakefield accelerators (LWFA)and plasma-driven wakefield accelerators (PWFA), with acceleration gradients surpassing 100 GV/m [1].Monoenergetic e-beams with multi-GeV energy, low emittance, and large beam charge have been generated in many LWFA experiments [2,3,4,5,6,7,8]. The quality of electron beams (e-beams) has continuously improved with the rapid development of plasma-based particle accelerators, including laser-wakefield accelerators (LWFA). Plasma-driven wakefield accelerators (PWFA), with acceleration gradients surpassing 100 GV/m [1]. Monoenergetic e-beams with multi-GeV energy, low emittance, and large beam charge have been generated in many LWFA experiments [2,3,4,5,6,7,8]. The e-beam dephasing length resulting from the accelerated electrons eventually outruns the laser-driven wakefield (vph < c), which limits the energy gain of the electrons in an LWFA [9]. Electrons were accelerated in 85 cm-long plasma and an energy gain of more than 42 GeV was obtained in the PWFA experiments [10].

Methods

Results

Conclusion