纵向高斯型密度分布下电荷束团的自场能与发射度增长

^FREE ENERGY AND EMITTANCE GROWTH CAUSED BY LONGITUDINAL GAUSSIAN DISTRIBUTION COMBINED WITHDIFFERENT TRANSVERSE DISTRIBUTIONS IN LINAC

在直线加速器中纵向高斯型密度分布的假定下，推得了纵向高斯型密度分布与横向密度分布分别为均匀型（Ｋ－Ｖ）、水袋型（ＷＢ）、抛物线型（ＰＡ）和高斯型（ＧＡ）相组合情况下的非均匀密度分布的自场能公式及相应的束流发射度增长；并且通过数值计算，给出了束团自场能及发射度随加速器和束团参数变化的图表。

The nonlinear space charge effect of bunched beam in linac is one of the important factors in- ducing the eminence growth due to the conversion of the field energy to kinetic energy . In this paper, using a cylinder model of space charge in linac, we derived the internal field energy for a bunched beam with some nonuniform space charge distributions. such as longitudinal Gaussian dis- tribution combined with each of Kapchinskij-Vladimirskij , waterbed, parabolic and Gaussian transverse distributions . And the eminence growths caused by above different distributions are Worked out .