电子初始位置对高能电子空间及时间辐射特性的影响

Influence of electron initial position on space and time radiation characteristics of high energy electrons

为了研究电子初始位置对圆偏振紧聚焦激光脉冲中高能电子的运动时间谱和空间分布特征的影响,本文通过结合相关理论,对高能电子的全时间运动方程和空间运动方程进行推导,同时运用MATLAB程序进行数值模拟,作出空间辐射三维图和时间谱。结果表明,当激光脉冲中电子的初位置逐渐向+z方向移动时,空间辐射特征呈现出四向对称性的趋势,单位立体角辐射功率时间谱中峰值辐射的半高全宽(FWHM)也不断增大,从初位置为z=-10λ_(0)时的3.5 as变为z=10λ_(0)时的7.9 as,并且与初始位置成近似正向线性关系,因此可以得到电子初位置对电子的能量分布有较大影响的结论,这也为后续研究电子初位置对激光脉冲中高能电子的辐射影响提供了一定的理论基础。

In order to study the influence of the initial position of electrons on the motion time spectrum and spatial distribution characteristics of high-energy electrons in circularly polarized tightly focused laser pulses,the equations of full-time motion and spatial motion of high-energy electrons are deduced theoretically,and the three-dimensional radiation diagram and time spectrum are made by numerical simulation with MATLAB.We can conclude from the results that in the laser pulse,while the initial position of the electron gradually moves in the+z direction,the spatial radiation characteristics have a trend of four-dimensional symmetry.There is also a certain positive and linear relationship between the initial position and the full width half maximum(FWHM)of the peak radiation in the time spectrum of unit solid angle radiation power.Specifically,the FWHM changes from 3.5as when z=-10λ_(0)to 7.9as when z=10λ_(0).In conclusion,the initial position of the electron has a great impact on the energy distribution of the electron,which provides strong support for the follow-up study of the influence of the initial position of electrons on the radiation of high-energy electrons in laser pulses.