Graduate School, China Academy of Engineering Physics, Beijing 100088, People's Republic of China.
Institute of Applied Physics and Computational Mathematics, Beijing 100094, People's Republic of China.
Phys Rev E. 2017 May;95(5-1):053205. doi: 10.1103/PhysRevE.95.053205. Epub 2017 May 9.
It was shown that in the interactions of ultra-intense circularly polarized laser pulse with the near-critical plasmas, the angular momentum can be transferred efficiently from the laser beam to electrons through the resonance acceleration process. The transferred angular momentum increases almost linearly with the acceleration time t_{a} when the electrons are resonantly accelerated by the laser field. In addition, it is shown analytically that the averaged angular momentum of electrons is proportional to the laser amplitude a_{L}, and the total angular momentum of the accelerated electron beam is proportional to the square of the laser amplitude a_{L}^{2} for a fixed parameter of n_{e}/n_{c}a_{L}. These results are verified by three-dimensional particle-in-cell simulations. This regime provides an efficient and compact alternative for the production of high angular momentum electron beams, which may have many potential applications in condensed-matter spectroscopy, new electron microscopes, and bright x-ray vortex generation.
研究表明，在超强度圆偏振激光脉冲与近临阈等离子体的相互作用中，通过共振加速过程，激光束中的角动量可以有效地传递给电子。当电子通过激光场共振加速时，传递的角动量随加速时间 t_{a}几乎呈线性增加。此外，通过解析还表明，电子的平均角动量与激光幅度 a_{L}成正比，而对于固定参数 n_{e}/n_{c}a_{L，加速电子束的总角动量与激光幅度 a_{L}^{2}成正比。这些结果通过三维粒子模拟得到了验证。这种机制为产生高角动量电子束提供了一种高效紧凑的替代方法，这在凝聚态物质光谱学、新型电子显微镜和明亮的 X 射线涡旋产生等方面有很多潜在的应用。
