Simulations of space-charge limiting currents in gyro-type devices

Summary form only given, as follows. The Air Force Phillips Lab is investigating frequency-tunable high power microwave sources, in particular, gyro-BWOs. To produce high power sources, it is necessary to provide as much beam power to the system as possible. This, in turn, means knowing the maximum amount of beam current that is possible to transport in any given system. Investigations of the dynamic interactions which occur between the growing electromagnetic waves generated in a gyro-type device and an electron beam with non-zero perpendicular velocity operating near the space-charge limiting current are being performed with the 2-1/2 D code MAGIC, and are compared to the analytic equations already in existence. Results show that beams of this nature reach a space-charge limiting effect at lower currents than those values predicted from theory. This leads to a pulse-limiting effect, thus limiting the amount of energy that can be produced from this type of beam.