摘要
Using kinetic coupling mode theory of three waves,the effect of longitudinal momentum spread in ion-ripple laser(IRL),which is an advanced new scheme to generate tunable-coherent radiation with frequency ranging from microwaves to x-rays,is investigated.For a Gaussian distribution in beam longitudinal momentum,the results show that the growth rate of IRL falls off rapidly with increasing momentum spread,and the momentum spread causes linear damping of beam space-charge wave,weakening the beam-radiation mode coupling and lowering the output radiation frequency apart from broadening the radiation spectrum.The dispersion relation and phase matching conditions are also obtained.