Effects of input voltage rise time on the performance of magnetron with diffraction output

High Power Microwave (HPM) usually refers to sources with output power higher than 300 MW, and the approach to achieve such high output power is related to the use of pulsed power (PP) technology, which stores energy over a relatively long time and releases it within a relatively short time to achieve high output power. In this process, the ideal high-voltage output is a square waveform; however, such a waveform is difficult to achieve in reality. This paper analyzes the effects of the output waveform from the PP system, particularly the voltage rise time, on a HPM source called a magnetron with diffraction output (MDO), which is a compact HPM source with split cathodes, using a particle-in-cell (PIC) code. Explosive field emission current, particle distribution, microwave output power, and main oscillation frequency under several input high voltage waveforms from PIC code simulations are presented. The simulation results indicate that a fast rise time is critical to generate high output power from MDO, but the trade-off is the shorter pulse length that comes with the fast rise time of the high voltage pulse, which leads to lower total energy deposited on the target.