An improved 1-D model for ultra high power radiation pulse propagation in the helical wiggler free electron laser

A one dimensional model of a helical wiggler Free Electron Laser is presented that does not average the Maxwell-Lorentz equations describing the interaction between electrons, wiggler and radiation fields. Furthermore, no relativistic approximations in the equations governing electron motion are made and transverse motion of the electrons is self-consistently driven by both the wiggler and radiation fields. Numerical solutions of the resultant equations allow for the modeling of radiation pulses with peak powers orders of magnitude greater than the steady state saturation value and with pulse widths significantly less than one radiation period. Preliminary numerical modeling of such pulses was investigated by simulating injection of a suitable high power seed pulse into an FEL amplifier. These studies suggest a possible new regime of operation where sub-period radiation pulses may extract energy from the electrons in a periodic burst mode.