Electrodynamic beam loading and pulse shortening effects due to a intense relativistic electron beam/plasma

Summary form only given. We report on investigations of the non-neutral plasma effects in HPM devices. We discuss how the intense space charge associated with the electron populations in HPM devices is sufficient to produce reflecting boundary conditions to RF energy, and how this can produce beam loading and pulse shortening in a variety of devices. Starting with a simple model for a parallel plate transmission line, we derive conditions for the impedance change due to an electron beam. Discussion of how this phenomena is evident in more complex HPM devices will follow, including a description of pulse shortening in the RKO and the importance of this effect for efficient MILO operation.