High power microwave generation at high repetition rates
Generation of microwaves at high power has progressed largely with single shot devices. Yet applications require repetitive operation at substantial repetition rates, implying high average power. This requires operation in a new domain for microwave devices. The technical challenge is to achieve very high electric fields in the source on a repetitive basis. We describe experiments on CLIA, a Compact Linear Induction Accelerator, generating 750 kV, 10 kA using magnetic switching to produce 60 ns pulses. We describe experiments with relativistic magnetrons and klystrons in the 1 GW, 100 Hz domain. As a first application we used CLIA to drive a water-cooled L-band magnetron at repetition rates as high as 250 Hz with no breakdown or pulse shortening. This gave 6.3 kW average power. A short burst at 1 kHz operated at ≈25 kW. In this regime operation is not limited by gas build-up, electrode erosion or microwhisker depletion. We are now operating on CLIA with relativistic klystrons of both the high current and low current varieties. Beams with modulated current powers of ≈ 1 GW have been generated at 200 Hz for bursts as long as 1000 pulses.
Relativistic magnetron development for use in a lightweight, repetitively pulsed, portable HPM transmitter
The design and development of a relativistic magnetron for use on a portable, repetitively pulsed high-power magnetron (HPM) transmitter is described. Operation of the magnetron at peak power levels of 700 MW, efficiencies of 15%, pulse widths up to 50 ns, output energies of 15 J, and repetition rates of 2 Hz is described. Frequency variation of the magnetron by varying the cathode radius is described, and frequency change during the magnetron pulse is analyzed. Practical system design considerations such as integration, lifetime, reliability, and reproducibility are discussed. >
Generation of a high‐power rf pulse in a rectangular waveguide
High‐power rf radiation with a frequency of 800 MHz was extracted from a modulated intense relativistic electron beam into a rectangular waveguide. The rf extraction was limited to a rf power below 500 MW. Problems which prevent generation of higher power were identified and solutions offered.