Mode Coupling in Bounded, Cold Beam-Plasma Systems

摘要

The study is concerned with the problem of guided wave propagation and electron beam interaction in bounded systems containing a plasma. The model used in the study is a circular conducting guide partially filled with a uniform, stationary, zero-temperature plasma contained with a finite axial dc magnetic field. For the electron beam interaction study the beam is assumed to be of uniform cross section and perfectly neutralized. The modes which exist in such a system are studied from two points of view. First a detailed treatment using the quasi-static assumption is given. The second portion of the study of the modes is directed at including the effects of the divergence free fields which are neglected in the quasi-static approximation. The interaction of a neutralized electron beam with the modes in the finite plasma system is investigated by means of normal mode and variational techniques. The results of an experiment using a thermal cesium plasma which qualitatively verify the mode splitting and deformation predicted by the coupled mode theory are presented.