Excitation of short-wave radiation in periodic structures

The main goal of this report is to show that in periodic structures, such as periodically non-uniform dielectric structures or periodic potentials, the nonrelativistic charged particles might radiate as relativistic. Special interest is given to the radiation of oscillators in such structures. Their radiation spectrum maximum is near to high-number harmonics. Using such radiation peculiarities, we can expect to create new types of generators, that can excite short-wave radiation (up to soft X-ray radiation) using only nonrelativistic charged particles. Such generators looks like free electron lasers (FEL). That is why we can call them nonrelativistic FELs. These generators have two significant advantages over the usual FEL. First of all, they use ensembles of nonrelativistic particles, which are simpler to create than relativistic ensembles. Second, the density of these ensembles can be very large. It is restricted only by the solid state density. It means that we can expect to realize collective (induced) radiation even in the X-ray band.