A distributed pumping model for a repetitive operated magnetically insulated transmission line oscillator

As one of the high power microwave sources, a magnetically insulated transmission line oscillator (MILO) works well in single shot mode. Recent interest has been focused on the repetition rate (rep-rate) operation of the device and it is important to improve the vacuum condition during the pulse bursts. In this paper, a dynamic pumping model for an L-band MILO was developed for the molecular movement and collision in the high-current vacuum diode chamber and the MILO tube on the basis of the Monte-Carlo method. According to the three dimension particle distribution, the idea of distributed pumping was proposed. In this way, another pump system close to the velvet cathode was introduced and located at the end of the MILO tube. Simulation results were verified through the experimental test carried out on a repetitive operated, high-voltage modulator, Torch-01 pulser. Results show that the distributed pumping can efficiently reduce the characteristic time of the pressure drop to one-fifth that of the single pumping. It is also indicated that the distributed pumping model has the potential for helping the MILO operate under rep-rate mode.