紧聚焦线偏振强激光场中横向初始位置对电子辐射特性的影响  

Influence oftransverse initial position on the radiation characteristics ofelectrons in strong tightly focused linearly polarized laser field

作　　者：华欣竹 沈曈 李可 王宇博 田友伟[2] 严刚[2] HUA Xinzhu;SHEN Tong;LI Ke;WANG Yubo;TIAN Youwei;YAN Gang(Bell Honors School,Nanjing University of Posts and Telecommunications,Nanjing 210023,China;College of Science,Nanjing University of Posts and Telecommunications,Nanjing 210023,China)

机构地区：[1]南京邮电大学贝尔英才学院,南京210023 [2]南京邮电大学理学院,南京210023

出　　处：《光散射学报》2022年第4期278-283,共6页The Journal of Light Scattering

基　　金：国家自然科学基金资助项目(No.10947170)。

摘　　要：为了探究紧聚焦线偏振激光场中高能电子辐射与电子横向初始位置的关系,在拉格朗日方程的基础上,构建了单个高能电子与激光脉冲相互作用散射的模型,并且借助MATLAB数值模拟获得了电子运动与电子辐射相关数据。初始状态静止的高能电子与紧聚焦线偏振强激光相互作用后,其在xOz平面内先作振荡运动,再沿z轴正方向作直线运动,横向速度随振荡逐渐转化为纵向速度。观察其有趣的运动轨迹、频谱调制结构与空间辐射分布,发现电子横向初始位置对于电子运动、辐射强度与辐射分布均有较大影响。随着横向初始位置正向增大,电子运动方向迅速偏移z轴,横纵速度失去对称性。最大频谱幅值和最大辐射强度随着横向初始位置增大存在一个极大值,对应辐射方向方位角保持不变,同时极角渐大。结果表明,激光脉冲正中心并不是获得最大强度电子辐射的最佳位置,在x=0.085λ0时可以取到最大辐射强度,对应极角大约为17°,方位角为0°。The scattering model of a single high-energy electron interacting with a Gaussian laser pulse is constructed on the basis of Lagrange’s equation to explore the relationship between high-energy electron radiation and the transverse initial position of electrons in tightly focused intense laser pulse line polarization.And data on electron motion and electron radiation were obtained with the help of MATLAB.After the interaction between the high-energy still electrons and strong tightly focused linearly polarized laser,they first oscillate in xOz plane,and then make a linear motion in the positive direction of the z-axis,with its lateral velocity gradually converting to the longitudinal velocity.Observing the interesting motion trajectory,spectral modulation structure,and spatial radiation distribution,it is found that the transverse initial position of the electron shows great impacts on electron movement,radiation intensity,and radiation distribution.As the transverse initial position of the electron increases positively,the direction of electron motion is rapidly shifted by the z-axis,and the transverse and vertical velocity loses its symmetry as well;there exist maximum values of the maximum spectral amplitude and the maximum radiation intensity with the increase of the transverse initial position,of which the radiation direction keeps its azimuth angle unchanged and the polar angle expanding.It is demonstrated that the center of laser pulse is not optimal for obtaining the brightest and hardest source of electromagnetic radiation.The hardest radiation pulse is generated when the initial position is set to 0.085λ0,with the maximum radiation energy at 1.34×10^(8),the polar angle is about 17°,and the azimuth angle is 0°。

关 键 词：电子辐射 横向初始位置 强激光 紧聚焦脉冲 数值模拟 

分 类 号：O411.3[理学—理论物理]