  A mechanism of stimulated emission of electromagnetic radiation by an
electron beam in carbon nanotubes is theoretically considered. Three basic
properties of carbon nanotubes, a strong slowing down of surface
electromagnetic waves, ballisticity of the electron motion over typical
nanotube length, and extremely high electron current density reachable in
nanotubes, allow proposing them as candidates for the development of nano-scale
Chernekov-type emitters, analogous to traveling wave tube and free electron
laser. Dispersion equations of the electron beam instability and the threshold
conditions of the stimulated emission have been derived and analyzed,
demonstrating realizability of the nanotube-based nanoFEL at realistic
parameters of nanotubes and electronic beams.
