Description:
<jats:p>A general theoretical consideration is given for the stimulated Raman scattering in a finitely magnetized relativistic electron beam on which the operation of the Raman-type free-electron laser is based. After some preliminary discussion, the coupled mode equations are derived which relate the pump wave (assumed to be an electromagnetic wave), the scattered wave and the electron plasma wave (negative-energy wave). From the coupled mode equations obtained above, the linear growth rate for the scattered and electron plasma waves is found. Then, the energy relations are formulated for the three waves involved in the process of the stimulated Raman scattering, together with the discussion on the energy balance among these waves. A special attention is paid to the behavior of the scattered wave in the vicinity of the cyclotron resonance. Some of the important features brought about by the cyclotron resonance are as follows: (a) According to the conditions imposed on the frequency and wave number of the pump wave, the scattered wave becomes either the electromagnetic wave mode or the electron cyclotron wave mode, or it is not excited. (b) In the presence of a finite static magnetic field, the spatial growth rate for the electromagnetic wave mode takes a maximum value for a particular set of various parameters, and the maximum growth rate becomes one order of magnitude or more as large as the growth rate for the case that there is no static magnetic field applied.</jats:p>