Xu X L, Pai C-H, Zhang C J, Li F, Wan Y, Wu Y P, Hua J F, Lu W, An W, Yu P, Joshi C, Mori W B
University of California, Los Angeles, California 90095, USA.
Department of Engineering Physics, Tsinghua University, Beijing 100084, China.
Phys Rev Lett. 2016 Jul 15;117(3):034801. doi: 10.1103/PhysRevLett.117.034801.
Ionization injection is attractive as a controllable injection scheme for generating high quality electron beams using plasma-based wakefield acceleration. Because of the phase-dependent tunneling ionization rate and the trapping dynamics within a nonlinear wake, the discrete injection of electrons within the wake is nonlinearly mapped to a discrete final phase space structure of the beam at the location where the electrons are trapped. This phenomenon is theoretically analyzed and examined by three-dimensional particle-in-cell simulations which show that three-dimensional effects limit the wave number of the modulation to between >2k_{0} and about 5k_{0}, where k_{0} is the wave number of the injection laser. Such a nanoscale bunched beam can be diagnosed by and used to generate coherent transition radiation and may find use in generating high-power ultraviolet radiation upon passage through a resonant undulator.
电离注入作为一种可控注入方案具有吸引力，可用于基于等离子体尾波场加速产生高质量电子束。由于与相位相关的隧穿电离率以及非线性尾波中的俘获动力学，尾波中电子的离散注入被非线性映射到电子被俘获位置处束流的离散最终相空间结构。通过三维粒子模拟对该现象进行了理论分析和研究，结果表明三维效应将调制波数限制在大于2k₀和约5k₀之间，其中k₀是注入激光的波数。这种纳米级聚束束流可通过相干渡越辐射进行诊断，并可用于产生相干渡越辐射，在通过共振波荡器时可能用于产生高功率紫外辐射。
