脉宽对激光撞击电子辐射峰值影响的模拟计算

为了研究激光脉宽对撞击电子后产生的辐射能量分布, 采用模拟计算的方法, 以Lorentz方程以及电子辐射方程为基础, 建立了紧聚焦激光作用于静止单电子模型, 并通过MATLAB软件模拟了不同脉宽下的激光脉冲与电子作用后产生的电子辐射能量分布, 对飞秒紧聚焦椭圆偏振激光脉冲的脉宽与电子间的辐射功率峰值进行了深入研究。结果表明, 当紧聚焦激光脉冲遇到静止单电子, 在激光脉冲撞击电子时, 电子会发出辐射; 散射辐射在散射方向的中心呈尖锥状积累; 随着激光脉宽的增加, 辐射功率分布逐渐呈现出双峰形; 脉冲宽度越宽, 电子辐射功率峰值越小, 脉宽为10λ₀时的峰值功率仅为脉宽为0.1λ₀时峰值功率的1%(初始脉宽λ₀=3.33fs), 同时辐射功率达到峰值所需时间越长, 最高峰的持续时间越长, 频谱函数的截止频率越低, 高频分量变少, 谐波次数增加。该结果对激光空气等离子体诊断方面具有重要意义。

Simulation calculation of the influence of pulse width on the peak radiation of laser impact electron

In order to study the radiation energy distribution of laser pulse width after impact electron, the method of simulation calculation was adopted. Based on Lorentz equation and electron radiation equation, a single electron model of compact focusing laser acting on static single electron was established. The distribution of electron radiation energy produced by laser pulse and electron action under different pulse width was simulated by MATLAB software. The pulse width of femtosecond compact focusing elliptic polarization laser pulse and the peak radiation power between electrons were studied. The simulation results show that when the compact focused laser pulse encounters a stationary single electron, the electron radiates while the laser pulse hits the electron. The scattering radiation accumulates in a sharp cone at the center of the scattering direction. With the increase of laser pulse width, the distribution of radiation power gradually presents a double peak. The wider the pulse width, the smaller the peak value of electron radiation power. When the pulse width is 10λ₀, the peak power is only 1% of that when the pulse width is 0.1λ₀, and the initial pulse width is λ₀=3.33fs. At the same time, the wider the pulse width, the smaller the peak value of the electronic radiation power, the longer the required realization of the peak radiation power, the longer the duration of the peak, the lower the cut-off frequency of the spectrum function, the less high frequency components, and the increase of the harmonic frequency. The results are of great significance to the diagnosis of laser air plasma.