Vacuum electron devices, instead of solid-state devices, provide potentially the best engineering solutions for many microwave system functions involving high power, high efficiency and certain kinds of harsh environments. The current effort to expand the state-of-art of high power microwave electron devices has intensified the need to understanding the highly nonlinear and dispersive nature of the interaction between electrons and rf fields. The current research will investigate the situation where the self-contraction of a slow- circuit-wave in an electron cloud results in the formation of electric field solitons and convective electron vortices in the electron-rf interaction space of a microwave crossed-field amplifier (CFA). The experiments include (1) simulation of a simple CFA device using a pure electron plasma and standard plasma diagnostics; and (2) development of advanced diagnostic techniques to search for the existence of solitons in a commercial 425 MHz CFA. The proposed work can establish the much needed physical basis for the application of a soliton based theory to understand highly nonlinear effects in high power microwave devices. The proposed work is also very fundamental in nature and may foster the transfer of several well-established plasma concepts to the study of microwave electron devices.
