Parametric interaction of longitudinal and transverse waves is studied for a double-beam system. The coupling between a transverse wave or a wiggler, and a longitudinal wave causes stimulated collective oscillations enhanced by double-stream amplification. These enhances oscillations are transformed by the wiggler into transverse waves and thus provide a source of radiation of the free electron laser. The analysis suggests new possibilities concerning free-electron laser operation. (au).
Wilhelmsson, H 
- Laboratoire de Physique des Milieux Ionises, Ecole Polytechnique, Palaiseau (France)