论文标题
一种自洽的数值方法，用于跟踪与电磁场模式相互作用的粒子
A self-consistent numerical approach to track particles in FEL interaction with electromagnetic field modes
论文作者
论文摘要
在本文中，我们提出了一种基于有限数量的辐射模式中电磁场的分解来进行FEL模拟的新方法。每种模式振幅的演变仅由能量保护决定。该代码是作为一般粒子示踪框架的扩展而开发的，并为FEL社区已经可用的一系列已建立的数值模拟添加了重要功能。该方法不是基于周期平均近似值，并且可以处理长波长的波导叶片，因为可能包括边界的分散效应。 futhermore，它正确模拟了较低的电荷系统，在较低的电荷系统中，横向和纵向空间电荷力仍然在动力学中起重要作用。对于自由空间的FEL相互作用，可以使用源相关的扩展近似值来限制对场曲线建模并加快系统演化计算所需的横向模式的数量。详细研究了三个示例，包括单个通过FEL放大器，高效率TESSA266场景和在零滑行方案中运行的THZ波导FEL。
In this paper we present a novel approach to FEL simulations based on the decomposition of the electromagnetic field in a finite number of radiation modes. The evolution of each mode amplitude is simply determined by energy conservation. The code is developed as an expansion of the General Particle Tracer framework and adds important capabilities to the suite of well-established numerical simulations already available to the FEL community. The approach is not based on the period average approximation and can handle long-wavelength waveguide FELs as it is possible to include the dispersion effects of the boundaries. Futhermore, it correctly simulates lower charge systems where both transverse and longitudinal space charge forces still play a significant role in the dynamics. For free-space FEL interactions, a source dependent expansion approximation can be used to limit the number of transverse modes required to model the field profile and speed up the calculation of the system evolution. Three examples are studied in detail including a single pass FEL amplifier, the high efficiency TESSA266 scenario and a THz waveguide FEL operating in the zero-slippage regime.
