Transient electromagnetic fields excited by bunches of charged particles in cavities of arbitrary shape

The electromagnetic fields excited by arbitrarily shaped bunches of charged particles travelling through accelerating structures with cylindrical symmetry are calculated by a numerical method solving Maxwell's integral equations in the time domain. The computer program based on this method calculates transient electromagnetic fields as well as the total energy radiated and the energy gain of particles inside the bunch. The shape of the accelerating structure may be defined by the user and can be approximated in a mesh of up to 50,000 nodes. The electric field-lines of a Gaussian bunch passing through a LEP cavity are shown. (Auth.)