High current cerencov free electron laser-CFEL at far infrared wavelengths

At present the so-called cerencov free electron laser-CFEL-is given much experimental and theoretical attention to [1–3]. In CFEL the electron beam propagates near the dielectric surface and excites a slow electromagnetic wave with the phase velocity that is somewhat less then beam´s one: vph = βph c = ω/kc v0 = β0 c where v0 is beam velocity, and transfer its kinetic energy to the radiation.