Experimental Investigation on Low Magnetic Field Operation of an Overmoded Slow-Wave High-Power Microwave Generator

The experimental results of an overmoded slow-wave high-power microwave generator operated at low magnetic field are presented. The feasibility of low magnetic field operation is investigated both theoretically and experimentally based on the characteristics of the overmoded slow-wave device. The experiments were carried out at the Spark-2 accelerator. Under the condition of guiding magnetic field strength of 0.55T, diode voltage of 474kV, and beam current of 5.2kA, a microwave was generated with power of 510MW, mode of TM₀₁, and frequency of 9.54GHz. The relative half-width of the frequency spectrum is less than 1%, and the beam-to-microwave efficiency is about 21% in our experiments.