Transverse velocity modulated e-beam propagating through an undulator as asource of coherent spontaneous radiation

A new kind of e-beam bunching enabling the production of coherent spontaneo us emission (CSE) is proposed and considered. It is shown that an a-beam in passing through an undulator will induce CSE along with incoherent spontan eous radiation on the same wavelength if the e-beam transverse velocity is modulated with a spatial period twice as long as the radiation wavelength. Such angular modulated beams can be regarded as alternatives to conventiona lly density modulated beams for CSE production. Requirements for e-beams ar e similar in both cases. (C) 1999 Published by Elsevier Science B.V. All ri ghts reserved.