Relativistic electron motion in FEL-like fields taking retarded interactions into account

Summary The interaction of two charged particles both with each other (via Lienard-Wiechert retarded potentials) and with the wiggler field of an FEL structure, along which they are launched, is computed by means of the numerical integration of the relativistic motion equations, taking also an incoming laser wave into account. The bunching effect characterizing the collective behaviour of an electron beam in FEL-like fields is simulated by assuming one of the particles to be a suitable macrocharge.