Time Domain Boundary Element Analysis of Wake Fields in Long Accelerator Structures

Abstract

Index Terms-Boundary element method, moving window, parallelization, scattered fields, short-range wake field.

Three-Dimensional Wake Field Computations Based on Scattered-Field Time Domain Boundary Element Method

“…In order to compute the short-range wake fields of a short bunch traversing long accelerator structures at low calculation costs, we can apply the integral equation formulation of moving window technique [11] into the full 3-D, A3D and 2.5-D S-TDBEM schemes presented above. The implementations of the moving window technique for their S-TDBEM schemes are straightforward.…”

“…The inversion of the matrix can be easily performed. The technique presented in [11] brings us drastic savings of required memory in the above S-TDBEM schemes. Then, the calculation time in turn becomes the most significant problem in computational point of view because the number of the reduced coefficient matrices still depends linearly on the total length of an accelerator structure (in realistic accelerator problems the transverse dimension of a structure is usually much smaller than the longitudinal size).…”

“…This quadratic scaling law is a main drawback of the moving window technique of TDBEM compared to the moving window implementation in FIT scheme because the scaling is only linear in a FIT scheme with moving window technique. For this problem, a parallelization algorithm [11] has been proposed. This can be also applied to the full 3-D, A3D and 2.5-D S-TDBEM schemes.…”

“…For 3-D problems, however, the simulations can be performed only for modest numerical models [10] because applicable model size is severely limited by very large memory requirements of the 3-D TDBEM scheme. In order to deal with practical long accelerator structures in the framework of TDBEM, the integral equation formulation of moving window technique was proposed [11]. This moving window technique was combined with a TDBEM scheme based on the scattered field formulation [12] which is called as Scattered-field Time Domain Boundary Element Method (S-TDBEM).…”

“…This moving window technique was combined with a TDBEM scheme based on the scattered field formulation [12] which is called as Scattered-field Time Domain Boundary Element Method (S-TDBEM). The 2-D S-TDBEM calculations with moving window technique were applied for the TESLA accelerator cavities and tapered collimators [11].…”