摘要:
正 電荷密度法是一種數(shù)值求解積分方程的方法,用于設計靜電透鏡系統(tǒng)有很多優(yōu)點。它避開了真空邊界的賦值問題,從而有可能用較少內存、較短機時達到較高精度。如圖1所示,Ⅰ、Ⅱ、Ⅲ分別表示三個旋轉對稱的電極,陰影區(qū)表示待求場區(qū)。有限差分法要求事先給出虛線所示真空邊界點的電位,作為重復迭代的不變出發(fā)值,這是誤差的一個重要來源。為了減少這種誤差,可把虛線邊界擴大到足夠遠,從而按電位為零處理,但網(wǎng)格點數(shù)大大增加,往往達到不能接受的程度。電荷密度法則不需要處理真空邊界,也不需要劃分
Abstract:
The charge-density method is investigated mainly on the errors which arise from the finite segments and their distribution. It is proved that the higher accuracy will reach if more segments are chosen. at where the charge density is high and at the region nearby the area where the field is to be ealculated. A program is set up. The differencc between the ealeulated data. and the published ones given by E. Harting and F. H. Eead (1976) is less than 1%.
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