论文标题
级联EEHG-HGHG自由电子激光的优化和稳定性分析
Optimization and stability analysis of the cascaded EEHG-HGHG free-electron laser
论文作者
论文摘要
X射线自由电子激光器（XFELS）是探索和研究自然实现非凡进步的强大工具。通常，种子叶片是提供全相干软X射线脉冲的理想来源。受益于高频的上转效率，具有回声辅助的谐波产生（EEHG）和高增益谐波生成（HGHG）的级联配置具有有希望的前景，可在1 nm波长下产生完整的相干辐射。在本文中，我们使用上海高重复率XFEL和Extreme Light设施的参数设计和优化EEHG-HGHG配置。此外，我们系统地分析了基于各种起始电子梁的输出FEL性能的相对时机抖动对输出FEL性能的影响。密集的数值模拟表明，级联的EEHG-HGHG方案可以达到1 nm FEL脉冲，峰值功率高达15 gW。进一步的灵敏度分析表明，电子束和种子激光器之间的相对时机抖动对FEL性能有重大影响。 RMS的定时抖动为3 fs可以导致最终输出脉冲能量波动为29.16％。
X-ray free-electron lasers (XFELs) are powerful tools to explore and study nature for achieving remarkable advances. Generally, seeded FELs are ideal sources for supplying full coherent soft x-ray pulses. Benefiting from the high-frequency up-conversion efficiency, the cascading configuration with echo-enabled harmonic generation (EEHG) and high-gain harmonic generation (HGHG) holds promising prospects for generating full coherent radiation at 1 nm wavelength. In this paper, we design and optimize EEHG-HGHG configuration using parameters of Shanghai High-Repetition-Rate XFEL and Extreme Light Facility. In addition, we systematically analyze the effect of relative timing jitter on the output FEL performance based on various start-to-end electron beams. The intensive numerical simulations show that the cascaded EEHG-HGHG scheme can achieve 1 nm FEL pulses with peak power up to 15 GW. Further sensitivity analysis indicates that the relative timing jitter between the electron beam and seed laser has a significant impact on the FEL performance. The RMS timing jitter of 3 fs can lead to the final output pulse energy fluctuations of 29.16%.
