相对论电子束中激光拍频注入的太赫兹微聚束相干集体放大
Coherent collective amplification of terahertz microbunching seeded by laser frequency beating in relativistic electron beams
- Shanghai Advanced Research Institute, Chinese Academy of Sciences（中国科学院上海高等研究院）
- Extreme Light Infrastructure – Nuclear Physics (ELI-NP), Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering (IFIN-HH)（极光大设施-核物理（ELI-NP），霍里亚·胡卢贝伊国家物理与核工程研发研究所（IFIN-HH））
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
针对自由电子激光太赫兹源，建立非线性模型描述拍频激光加热器注入的微聚束集体演化，揭示短波长双峰机制并优化压缩分配，实现高效可预测的微聚束调控。
AI中文摘要：
基于自由电子激光的高功率、连续可调太赫兹源需要对电子束微结构进行精确控制。由于激光诱导的分布及其集体演化必须同时处理，因此在宽频率范围内定量预测调制幅度仍然具有挑战性。为了描述这种耦合演化，针对由拍频激光加热器注入的微聚束开发了一个非线性模型。通过光学相位平均获得非高斯加热器出口分布，并在六维相空间中通过多级压缩进行传播。保留了源诱导相关性，并自洽地评估了空间电荷、相干同步辐射和射频尾场效应。由此，波长相关的聚束响应与激光拍频、激光功率和压缩分配联系起来。发现短波长双峰主要由纵向空间电荷主导，而在固定总压缩下重新分配压缩可以增强选定波长附近的聚束。预测的源调制和下游响应分别与Elegant和IMPACT-Z基准进行了对比。不同激光脉冲能量下波长相关聚束因子的实验测量结果与理论和模拟预测的趋势吻合良好。所提出的框架为在自由电子激光设施中优化电子束微聚束以实现可调谐、高功率太赫兹产生提供了一条计算高效且可预测的途径。
英文摘要：
High-power, continuously tunable terahertz sources based on free-electron lasers require precise control of electron-beam microstructures. Quantitative prediction of the modulation amplitude across a broad frequency range remains challenging because the laser-induced distribution and its collective evolution must be treated together. To describe this coupled evolution, a nonlinear model is developed for microbunching seeded by a frequency-beating laser heater. The non-Gaussian heater-exit distribution is obtained by optical phase averaging and propagated through multistage compression in six-dimensional phase space. Source-induced correlations are retained, with space charge, coherent synchrotron radiation, and radio-frequency wakefields evaluated self-consistently. The wavelength-dependent bunching response is thereby connected to the laser beat frequency, laser power, and compression partition. The short-wavelength double peak is found to be governed mainly by longitudinal space charge, while bunching near a selected wavelength can be enhanced by redistributing compression at fixed total compression. The predicted source modulation and downstream response are benchmarked against Elegant and IMPACT-Z, respectively. Experimental measurements of the wavelength-dependent bunching factor at different laser pulse energies are found to agree well with the trends predicted by theory and simulation. The resulting framework provides a computationally efficient and predictive route to optimizing electron-beam microbunching for tunable, high-power terahertz generation at free-electron-laser facilities.
