Electronic Interaction Theory for Transverse-wave Couplers†

Abstract

This paper is concerned with a general theoretical analysis of the interaction between transverse waves propagating on a filamentary electron beam and electromagnetic circuits. The class of circuits considered is that for which the transverse electric and magnetic fields are symmetric with respect to the z-axis. Aside from this restriction on the symmetry properties, the analysis is quite general in the sense that the transverse electric and magnetic field components are arbitrary functions of axial distance. Therefore, the analysis is valid for a variety of circuit configurations, ranging from simple coupler circuits, serving the purpose of coupling r.f. power in and out of the beam in r.f. and d.c.-pumped devices, to transverse travelling-wave tubes and multi-cavity klystrons. The transverse field components in pump circuits used for parametric pumping and d.c. pumping of transverse waves are all antisymmetric with respect to the z-axis and are therefore excluded from the present analysis. The material ...