A free electron laser using a standing-wave wiggler

The operating parameters of an FEL employing a standing-wave microwave or laser radiation field as the wiggler (permitting spatial periodic lengths in the micron range and hence FEL output in the UV or X-ray range) are investigated analytically. It is shown that emission at shorter wavelengths requires shorter pump pulses. An average gain coefficient of about 0.5 (comparable to those obtainable with conventional static-magnetic-field wigglers) is estimated for an FEL operating at 500 nm with wiggler spatial period = 1 mm, radiation power density = 1 kW/sq cm, electron-beam gamma = 100, beam current density = 10 A/sq cm, and incident radiation power density = 10 MW/sq cm.