A Nonlinear Theory of the Beam-Wave Interaction in a Resistive Wall Amplifier

Based on the special interaction mechanism of the resistive wall amplifier (RWA) that there is no interaction between the circuit wave and the electron beam, and the further bunching of the electron beam is caused by the interaction between the electron beam and the space charge field driven by the plasma wave in the resistive wall, a nonlinear theory of the beam-wave interaction in RWAs is built in this article, and a corresponding 1-D code is developed. The 1-D large-signal model, which is not based on the equivalent circuit, is a universal model. Energy exchange is calculated based on the energy formula obtained from the electron equation of motion. A special method is used to represent the propagation and growth of space charge waves. And a special method was used to obtain an analytical expression for the space charge field when the current density expression was given. There is a good agreement between the results calculated by the large-signal code and by CST and previous experiments.