Modified Scheme of Asymptotic Integration in Theory of Multiharmonic Devices of High-Current Electronics Using Helical Relativistic Electron Beams

We have modified the method of averaged characteristics to solve multiharmonic problems in high-current devices that use a helical relativistic electron beams (REBs). We proposed a new substitution of variables in the framework of the averaged characteristics method. This substitution made it possible to increase the efficiency of the algorithm for solving the motion problem. We demonstrated the efficiency of the new scheme on the motion problems of a plasma-beam superheterodyne free-electron laser (SFEL) with the helical REB.