The short-range transverse wakefields in TESLA accelerating structure

The operation of a Free Electron Laser in TESLA project requires very short bunches. This results in a very long interaction length between the bunch and the wakefields. From this fact severe problems for computer simulations arise. The longitudinal case was recently studied intensively by Novokhatski et al.[1]. In this paper we study mainly the transverse forces. Using a recently developed time domain numerical approach, we calculate the short-range transverse wakefields of the TESLA linac accelerating structure. We also consider behaviour of transverse wake potential in a periodic array of cavities and compare it with wake potential of the TESLA quasi-periodic structure.