On the Importance of Fourth Order Effects on Wakefield Calculations for Short Bunches∗
نویسندگان
چکیده
The second-order FD-TD algorithm developed by Yee 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 secondorder 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 is presented, which reduces the truncation error two orders of magnitude. The results of the wakefunctions calculated by use of this fourth-order FDTD algorithm are presented and compared with the results of the second-order FD-TD algorithm.
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