Waveguides with dielectric filling: accelerating and undulator wakefield structures

Waveguides with dielectric filling and a vacuum channel for the passage of bunches are of interest for the development of new methods of wakefield acceleration in accelerating structures. Excitation of waveguides by relativistic electron bunches makes it possible to achieve accelerating field with a longitudinal component of strength E of the order of 100 MV/m and higher when using subterahertz and terahertz structures. The problem of ensuring beam stability in such waveguides is solved analytically and numerically based on an analysis of the self-consistent beam dynamics. The efficiency of energy transfer from the accelerating beam to the accelerated one is optimized on the bases of charge and energy profiling in one or multi-beam accelerating schemes. The possibility of transforming the parasitic effect of generating deflecting fields in dielectric accelerating wakefield structures into a useful effect for creating a wakefield undulator based on waveguides with periodic asymmetric dielectric filling is considered.