Computer Simulations of the Beam-Beam Interaction and Measurements with PETRA

The beam-beam interaction is simulated on a digital computer taking into account all three oscillation modes with quantum fluctuation and damping. It is shown that small asymmetries in phase advance between the interaction points and spurious dispersions at the interaction points are the main causes of an increase of the beam height and a corresponding loss of luminosity. A good agreement between simulations and measurements is found and the operating conditions for PETRA are improved according to the predictions of the simulations.