从一维结构因子到三维几何修正的长波段同步辐射光谱计算评估
Evaluation of Long-Wavelength Synchrotron Radiation Modeling from One-Dimensional Form Factor to Three-Dimensional Geometric Correction
聂寒松 1雷俊 1唐琳 1何建华1
作者信息
- 1. 武汉大学高等研究院;武汉大学先进光源研究中心
- 折叠
摘要
针对长波段同步辐射光谱计算中传统采用的“单电子辐射结合一维纵向结构因子”近似难以描述束团纵向相位关联、离轴相位失配及空间去相干的问题，基于统一的单电子频域复场内核，建立了包含非相干统计平均、严格复场叠加及一维/三维几何结构因子修正的多层级辐射模型，并在典型储存环参数下进行了数值比较。结果表明：在相干尚未建立且分布仍主要由单电子图样及其非相干背景主导的条件下，各模型均退化为单电子图样的线性放大；在相干过渡区，1D 结构因子模型系统性低估相干增强，且误差随束团电子数增加而放大；引入空间依赖的 3D 几何修正后，可在保持较高计算效率的同时更准确地描述相干增强的空间分布，并避免传统 1D 结构因子模型的系统性低估。相关结果可为同步辐射红外、THz 等长波段光谱精细计算及光源束线优化提供参考。
Abstract
Accurate modeling of long-wavelength synchrotron radiation is important for source characterization and beamline optimization. [Purpose]: To evaluate the limitations of the conventional one-dimensional longitudinal form-factor approximation in describing longitudinal phase correlation, off-axis phase mismatch, and spatial decoherence in bunch radiation. [Methods]: A hierarchical radiation framework was established on a unified single-electron frequency-domain complex-field kernel, including incoherent statistical averaging, strict complex-field superposition, and 1D/3D geometric form-factor corrections. Numerical comparisons were carried out under typical storage-ring parameters. [Results]: Under conditions where the distribution is still dominated by the single-electron pattern and its incoherent background, all models reduce to the linear scaling of the single-electron radiation pattern. In the coherence-transition regime, the one-dimensional form-factor model systematically underestimates the coherent enhancement, and the error increases with electron number. After introducing a spatially dependent three-dimensional geometric correction, the model can more accurately describe the spatial distribution of coherent enhancement while retaining relatively high computational efficiency. [Conclusions]: The proposed three-dimensional correction method provides a useful reference for long-wavelength synchrotron-radiation modeling and beamline optimization.关键词
长波段同步辐射/边缘辐射/相干增强/结构因子/空间去相干Key words
Long-wavelength synchrotron radiation/Edge radiation/Coherent enhancement/Form factor/Spatial decoherence引用本文复制引用
聂寒松,雷俊,唐琳,何建华.从一维结构因子到三维几何修正的长波段同步辐射光谱计算评估[EB/OL].(2026-05-18)[2026-05-21].https://chinaxiv.org/abs/202605.00120.学科分类
物理学
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