Collision off-axis position dependence of relativistic nonlinear Thomson inverse scattering of an excited electron in a tightly focused circular polarized laser pulse

This paper presents a novel view of the impact of electron collision off-axis positions on the dynamic properties and relativistic nonlinear Thomson inverse scattering of excited electrons within tightly focused, circularly polarized laser pulses of varying intensities. We examine the effects of the transverse ponderomotive force, specifically how the deviation angle and speed of electron motion are affected by the initial off-axis position of the electron and the peak amplitude of the laser pulse. When the laser pulse intensity is low, an increase in the electron's initial off-axis distance results in reduced spatial radiation power, improved collimation, super-continuum phenomena generation, red-shifting of the spectrum's harmonic peak, and significant symmetry in the radiation radial direction. However, in contradiction to conventional understandings,when the laser pulse intensity is relatively high, the properties of the relativistic nonlinear Thomson inverse scattering of the electron deviate from the central axis, changing direction in opposition to the aforementioned effects. After reaching a peak, these properties then shift again, aligning with the previous direction. The complex interplay of these effects suggests a greater nuance and intricacy in the relationship between laser pulse intensity, electron position, and scattering properties than previously thought.

激光脉冲初相位调制电子受激辐射后向对称性

为了研究线偏振超短超强激光脉冲中高能电子运动和辐射的后向对称性,基于经典非线性Thomson散射的框架,借助数值模拟软件绘制了电子轨迹、空间辐射能量的角分布和空间频率分布直方图。研究发现,当激光脉冲短至只有几个周期时,非线性Thomson散射受激光初始相位的影响十分显著,其能量空间分布和运动轨迹具有很强的相关性,并且相对于驱动激光的初始相位具有“三重对称”的特性。高次谐波频谱的截止可以达到1×10^(6)ω_(0),而频谱峰值的对称性则可为实际激光参数的选择提供可行的思路。研究表明,通过激光脉冲包络相位调制获得理想的非线性Thomson后向散射空间辐射角分布和高次谐波幅度峰值是可行的。