加速器中的相运动

he motion of charged particle can be divided by the longitudinal motion and the transverse motion. The longitudinal motion is the phase motion. Under one dimensional approximation,the longitudinal motion equations are derived, the physical mechanism for the stable phase motion and its related phase condition are given. The one standard map for the longitudinalmotion is gotten, this standard map can be used for the nonlinear dynamics study. We simulated two S-Band electron linacs to prove the basic theory of the phase motion. The simulationresult agreed the basic theory well. In the common electron linac (with DC electron gun and the bunching section), We propose to replace the high voltage DC electron gun by the<br />photocathode RF gun directly while preserving the bunching section still to get the high peak current short electron bunch.