Influence of quasi-electrostatic support on amplification of space charge waves in amplification section of a superheterodyne free electron laser

A theoretical study of the influence of a quasi-electrostatic support on the amplification level of the slow space charge wave (SCW) in the amplification section of a superheterodyne free electron laser (FEL) was carried out. One of the ways to significantly increase the saturation level of the slow SCW is maintaining the conditions of a three-wave parametric resonance between the slow, fast SCWs and the resulting pump electric field. This can be done by introducing the quasi-electrostatic support in the superheterodyne FEL amplification section. Also, it was found that the generated pump electric field significantly influences the maintenance of parametric resonance conditions. As a result, this increases the saturation level of the slow SCW by 70%. Finally, the quasi-electrostatic support significantly reduces the maximum value of the electrostatic undulator pump field strength, which is necessary to achieve the maximum saturation level of the slow SCW.