Ion Acoustic Wave Pumped Free Electron Laser

In this paper, the problem of free electron laser excitation by a relativistic electron beam passing through background plasma with ion acoustic wave as wiggler is studied. Under the case of Compton and Raman regime, both the linear dispersion relation and the growth are presented. The analysis makes no assumption on the relative relation of the beam density and the background plasma electron density, and the result is also fit to both ion ripple laser case and the large amplitude ion acoustic wave case.