Self-consistent Analysis of 3D Wake Fields in High Energy Particle Accelerators

基于时域边界元法（TDBEM），开发了粒子加速器尾流场的数值分析程序。TDBEM为下一代高能粒子加速器尾流场和带电粒子运动的自洽分析，特别是直线对撞机束团压缩段相干同步辐射的分析提供了诱人的可能性。在本项目期间，TDBEM程序是为轴对称的2D、3D和2.5D加速器腔系统开发的。而TDBEM在实际应用中遇到的最大问题就是对RAM容量的要求。为此，本文建立了MPI并行计算系统，并将TDBEM程序转换为MPI并行计算，验证了轴对称二维、三维和2.5维TDBEM程序的尾流势模拟结果与传统FDTD分析结果的一致性。MPI并行计算的可扩展性也给了我们很好的性能。同时，在程序中加入粒子轨道模拟程序，对尾流场和粒子动力学进行自洽分析，将TDBEM程序应用于真实的束流压气机的粒子动力学分析是今后的工作。

Numerical Codes for particle accelerator wake field analysis which are based on time domain boundary element method (TDBEM) are developed.The TDBEM gives us attractive possibility of self-consistent analysis of wake fields and charged particle motion in the next generation high energy particle accelerators, especially for analysis of coherent synchrotron radiation in bunch compressor section of the Linear Colliders.During the term of this project, the TDBEM codes were developed for axi-symmetric 2D,3D and 2.5D accelerator cavity systems. Then the biggest problem of TDBEM in practical use was requirement of big RAM capacity. For this, MPI parallel computation system was constructed and the TDBEM codes were turned to the MPI parallel computation.It was confirmed that the wake potential simulation showed us very good agreement with conventional FDTD analysis for all of axi-symmetric 2D,3D and 2.5D TDBEM codes. And scalability in MPI parallel computation also gave us very good performance. And then, at the same time, particle trajectory simulation codes were also included in the codes to do self-consistent analysis of the wake fields and particles dynamics.It will be future works to apply the TDBEM codes to analysis of particle dynamics in real bunch compressors.