Title :
On the importance of fourth order effects on wakefield calculations for short bunches
Author :
Li, Zenghai ; Bisognano, Joseph J.
Author_Institution :
CEBAF, Newport News, VA, USA
Abstract :
The second-order FD-TD algorithm developed by Yee (1966) has been successful in Wakefield calculations. However, unphysical results can be obtained in wakefunction calculations of very short bunches. A detailed study of this problem is presented in this paper. It is found that the truncation error inherent in the second-order Yee algorithm of standard codes is frequency dependent and is inadequate for wakefield calculations of short bunches which produce wakefields with high frequencies. A fourth order approach extending the work of J. Fang (1989) is presented, which reduces the truncation error two orders of magnitude. The results of the wakefunctions calculated by use of this fourth-order FD-TD algorithm are presented and compared with the results of the second-order FD-TD algorithm
Keywords :
beam handling techniques; finite difference methods; time-domain analysis; wakefield accelerators; Yee algorithm; fourth order effects; fourth order finite difference time-domain algorithm; fourth-order FD-TD algorithm; second order finite difference time-domain algorithm; second-order FD-TD algorithm; short bunches; truncation error; wakefield; wakefunctions; Code standards; Difference equations; Electromagnetic modeling; Energy loss; Finite difference methods; Finite wordlength effects; Frequency dependence; Maxwell equations; Numerical models; Time domain analysis;
Conference_Titel :
Particle Accelerator Conference, 1995., Proceedings of the 1995
Conference_Location :
Dallas, TX
Print_ISBN :
0-7803-2934-1
DOI :
10.1109/PAC.1995.505556
