Dense Helical Electron Bunch Generation in Near-Critical Density Plasmas with Ultrarelativistic Laser Intensities.

Ronghao Hu,Chia-erh Chen,Zhengming Sheng,Haiyang Lu,Xueqing Yan,Bin Liu,Chen Lin,Xiantu He,Meilin Zhou

doi:10.1038/srep15499

Abstract

The mechanism for emergence of helical electron bunch(HEB) from an ultrarelativistic circularly polarized laser pulse propagating in near-critical density(NCD) plasma is investigated. Self-consistent three-dimensional(3D) Particle-in-Cell(PIC) simulations are performed to model all aspects of the laser plasma interaction including laser pulse evolution, electron and ion motions. At a laser intensity of 1022 W/cm2, the accelerated electrons have a broadband spectrum ranging from 300 MeV to 1.3 GeV, with the charge of 22 nano-Coulombs(nC) within a solid-angle of 0.14 Sr. Based on the simulation results, a phase-space dynamics model is developed to explain the helical density structure and the broadband energy spectrum.

Highlights

LWFA regime has been studied thoroughly in theories[8,11,13,14], simulations[12,14,15,20] and experiments[16,17,21,22,23,24]
A theoretical model of electron phase-space dynamics was presented to explain the mechanism for emergence of HEB and PIC simulations were performed in a slab of NCD plasma interacting with a circularly polarized laser pulse, which was focused to a peak intensity of 1022 W/cm[2]
The incident laser pulse, with a wavelength of λL = 1.0 μm, is focused to a spot diameter of 3.6 μm in full width at half maximum(FWHM) with a Gaussian transverse field profile, which results in a peak intensity of about 1022 W/cm[2]

Summary

Introduction

LWFA regime has been studied thoroughly in theories[8,11,13,14], simulations[12,14,15,20] and experiments[16,17,21,22,23,24]. A theoretical model of electron phase-space dynamics was presented to explain the mechanism for emergence of HEB and PIC simulations were performed in a slab of NCD plasma interacting with a circularly polarized laser pulse, which was focused to a peak intensity of 1022 W/cm[2 ]

Results

Conclusion