A large-orbit nonwiggler free-electron laser

A large-orbit nonwiggler free-electron laser (FEL) is proposed that can be expected to operate efficiently with quite low magnetic fields in the range of millimeter and submillimeter waves. A kinetic description as well as the dispersion property is presented. The influences of the initial parameters on the normalized growth rate are numerically analyzed. Nonlinear simulation and discussion are carried out in detail.