On collinear wake field acceleration with high transformer ratio

The main subject of the presented paper is related to collinear wake field acceleration schemes with high transformer ratio driven by a train of charged particle bunches. Based on the energy conservation, causality and superposition of the induced fields, an optimal transformer ratio in such collinear wake field accelerators has been treated. The main features of the wake field excitation by the train of point, short and symmetric bunches in single and many mode structures have been studied. A numerical example for a collinear multi-bunch wake field accelerator with high transformer ratio is discussed.