真空中超强啁啾激光场下正电子产生的二维动量分布  

Two-dimensional momentum distribution of positrons in superchirped laser field in the vacuum

作　　者：任芝 尚大凯[1,3] 李松涛 杨世芳[2] 龚驰 REN Zhi;SHANG DaKai;LI SongTao;YANG ShiFang;GONG Chi(Department of Mathematics and Physics,North China Electric Power University,Baoding 071003,China;Department of Electrical Engineering,North China Electric Power University,Baoding 071003,China;Hebei Key Laboratory of Physics and Energy Technology,North China Electric Power University,Baoding 071003,China)

机构地区：[1]华北电力大学数理系,保定071003 [2]华北电力大学电力工程系,保定071003 [3]华北电力大学河北省物理学与能源技术重点实验室,保定071003

出　　处：《中国科学：物理学、力学、天文学》2024年第11期117-126,共10页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金(编号:12304337,52207154);中央高校基本科研经费(编号:20226943)资助项目。

摘　　要：运用数值求解量子动理学方程,研究了在不同形式超强啁啾激光场下真空中产生的正电子的二维动量谱分布,及不同啁啾系数下的粒子数密度.研究表明激光频率经过各种不同形式啁啾化后,在真空当中产生的正电子的二维动量谱呈现出明显的干涉效应,并且逐渐趋于各向同性,即正圆分布,这是啁啾场体现在二维动量谱上的显著特征.此外,还通过分析转变点结构来定性地理解发生各向同性、干涉效应的原因.对粒子数密度的研究表明,粒子数密度对啁啾系数非常敏感,随着啁啾参量的变化呈现出明显的周期性分布及增强,这在未来的实验中可以提供一种新的方式来增加正电子的产量.In this study,the two-dimensional momentum spectra of electron-positron pairs produced in vacuum under different forms of a strong chirped laser field and the particle number density under different chirped coefficients are investigated using the quantum dynamic equations.The two-dimensional momentum spectrum of positrons created in vacuum indicates an obvious interference distribution effect after the laser frequency is chirped in various forms.Moreover,the two-dimensional momentum spectrum gradually tends to be isotropic,i.e.,exhibits a normal circular distribution,which is a remarkable characteristic of the chirped field reflected in this spectrum.In addition,the reason for the interference effect can be qualitatively understood by analyzing the structure of turning points.Investigation of the number density of particles shows that it is very sensitive to the chirp coefficient.Moreover,the number density shows an obvious periodic distribution and enhancement with a change in the chirp parameter.This observation provides a new method for increasing the production of electron-positron pairs in future experiments.

关 键 词：强啁啾场 正负电子对 二维动量分布 

分 类 号：TN249[电子电信—物理电子学] O56[理学—原子与分子物理]