Tilted Snowplow Ponderomotive Electron Acceleration With Spatio-Temporally Shaped Ultrafast Laser Pulses
Tilted Snowplow Ponderomotive Electron Acceleration With Spatio-Temporally Shaped Ultrafast Laser Pulses
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DOI：
10.3389/fphy.2019.00066
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发表时间：
2019-05
影响因子：
3.1
通讯作者：
Alex M. Wilhelm;C. Durfee
中科院分区：
文献类型：
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作者：
Alex M. Wilhelm;C. Durfee
提出了一种利用倾斜超快激光脉冲的有质动力加速自由空间电子的新方案。强度包络的倾斜是由脉冲光谱的角色散引起的，并且减慢了脉冲与自由电子的相互作用。较慢的有效脉冲速度允许电子在保持在波上的同时从静止加速。我们提出了非相对论和相对论的分析单粒子模型在绝热有质动力近似，描述了一个理想的无限倾斜脉冲以及有限宽度的光束的过程。分析预测的阈值强度作为脉冲前倾角的函数，并表明，在理想情况下的输出能量的电子是四倍的有质动力势在捕获阈值。使用二维OSIRIS 4.0粒子在细胞代码的全场模拟确认的基本方案。这种倾斜的脉冲加速方案显示出作为实验室规模的方法的承诺，加速电子的MeV水平具有良好的能量和角分辨率，用于超快电子衍射或注入到第二级加速器。
We propose a novel scheme for using the ponderomotive force of a tilted ultrafast laser pulse to accelerate electrons in free space. The tilt of the intensity envelope results from the angular dispersion of the pulse's spectrum and slows down the interaction of the pulse with free electrons. The slower effective pulse velocity allows time for the electrons to accelerate from rest while remaining on the wave. We present both non-relativistic and relativistic analytic single-particle models in the adiabatic ponderomotive approximation, describing the process for an ideal infinite tilted pulse as well as a finite width beam. The analysis predicts the threshold intensity as a function of the pulse front tilt angle and shows that in the ideal case the output energy of the electrons is four times that of the ponderomotive potential at the capture threshold. Full-field simulations using the 2D OSIRIS 4.0 particle-in-cell code confirm the basic scheme. This tilted pulse acceleration scheme shows promise as a lab-scale method of accelerating electrons to the MeV level with good energy and angular resolution, to be used for ultrafast electron diffraction or injection into a second stage accelerator.