A Computer Simulation of Longitudinal Single-Bunch Effects in Electron-Positron Storage Rings

The computer code TRACK simulates longitudinal single-bunch effects in an electron-positron storage ring. The program tracks the turn-by-turn energy and phase deviations of N superparticles, where N is 100-1000. In addition to the usual RF and lattice parameters, an input to the program is the wake potential function for the ring vacuum chamber. The program has been applied to compute bunch lengthening in SPEAR as a function of charge per bunch. Although the computed results are in qualitative agreement with measurements, there are discrepancies in some details. Possible reasons for these discrepancies are discussed.