Investigation of a load-limited, magnetically insulated transmission line oscillator (MILO)

The magnetically insulated transmission line oscillator (MILO) is a crossed-field microwave tube that is closely related to the linear magnetron. We discuss research involving a MILO whose DC operating characteristics (voltage and impedance) are determined by a current-carrying load. The load also forms part of a unique power extraction scheme. We show that maximum power is obtained from the load-limited MILO when an RF choke is used for the upstream boundary. This efficiency-enhanced version of the load-limited MILO yields gigawatt-level output power in both experiments and numerical simulations, results of which are also presented. In addition, we use the parapotential theory of magnetically insulated transmission lines in conjunction with observed simulation results to obtain estimates of maximum spoke current, spoke drift velocity, and maximum efficiency.