Spin and polarization effects on the nonlinear Breit–Wheeler pair production in laser-plasma interaction

Huai-Hang Song,Yu-Tong Li,Bing-Jun Li,Jie Zhang,Yan-Fei Li,Li-Ming Chen,Wei-Min Wang,Zheng-Ming Sheng

doi:10.1088/1367-2630/ac0dec

Abstract

The spin effect of electrons/positrons (e −/e +) and polarization effect of γ photons are investigated in the interaction of two counter-propagating linearly polarized laser pulses of peak intensity 8.9 × 1023 W cm−2 with a thin foil target. The processes of nonlinear Compton scattering and nonlinear Breit–Wheeler pair production based on the spin- and polarization-resolved probabilities are implemented into the particle-in-cell (PIC) algorithm by Monte Carlo methods. It is found from PIC simulations that the average degree of linear polarization of emitted γ photons can exceed 50%. This polarization effect leads to a reduced positron yield by about 10%. At some medium positron energies, the reduction can reach 20%. Furthermore, we also observe that the local spin polarization of e −/e + leads to a slight decrease of the positron yield about 2% and some anomalous phenomena about the positron spectrum and photon polarization at the high-energy range, due to spin-dependent photon emissions. Our results indicate that spin and polarization effects should be considered in calculating the pair production and laser-plasma interaction with the laser power of 10 PW to 100 PW classes.

Highlights

Over the past decades, the intensity of lasers has increased rapidly [1, 2] with the laser technical progress based on chirped pulse amplification [3]
Our simulation results show that the positron yield is reduced by about 10% with the spin and polarization effects included for laser pulses with peak intensity 8.9 × 1023 W cm−2
Impacts of laser intensity and plasma density In figure 5(a), we investigate the difference of positron yield between with and without spin and polarization effects under various laser intensities a0, to find the laser intensity at which these two effects need to be taken into account

Summary

15 July 2021

Huai-Hang Song1,2 , Wei-Min Wang3,4,∗ , Yan-Fei Li5 , Bing-Jun Li5, Yu-Tong Li1,2,6,7,∗ , Zheng-Ming Sheng, Li-Ming Chen and Jie Zhang. University of China, Beijing 100872, People’s Republic of China 4 Collaborative Innovation Center of IFSA, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China 5 Department of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049, People’s Republic of China 6 CAS Center for Excellence in Ultra-Intense Laser Science, Shanghai 201800, People’s Republic of China 7 Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People’s Republic of China 8 Key Laboratory for Laser Plasmas (MoE) and School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China 9 SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG, United Kingdom 10 Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China ∗ Authors to whom any correspondence should be addressed

Introduction

Theoretical model and simulation method

Simulation results and analysis

Findings

Conclusion