Lesson plan

Vircator

A vircator (VIRtual CAthode oscillaTOR) is a microwave generator that is capable of generating brief pulses of tunable, narrow band microwaves at very high power levels. Its application is mainly in the area of electronic warfare, by way of interfering with electronic equipment such as radars or radio equipment. A typical vircator is built inside an evacuated resonant cavity or waveguide. An electrode, a cold cathode, at one end injects an intense electron beam, such as from a Marx generator or a flux compression generator, optionally with a suitable pulse-forming network, e.g. a Blumlein transmission line. The pulse has a magnitude in the range of hundred or more kilovolts and duration of about 50–150 nanoseconds. The electrons are attracted to a thin anode, such as an aluminized PET film or a stainless steel mesh, that is connected to the grounded waveguide body. The unit is surrounded by a magnet. Due to the intensity of the electron beam, many electrons pass through the anode into the region beyond it, forming a virtual cathode. The electron beam must be so intense as to exceed the space-charge-limiting current in that region, causing oscillations that generate microwaves. The frequency, efficiency and other characteristics of the emitted beam depend on the precise physical configuration and operating parameters.…

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Article summary

A vircator (VIRtual CAthode oscillaTOR) is a microwave generator that is capable of generating brief pulses of tunable, narrow band microwaves at very high power levels. Its application is mainly in the area of electronic warfare, by way of interfering with electronic equipment such as radars or radio equipment. A typical vircator is built inside an evacuated resonant cavity or waveguide. An electrode, a cold cathode, at one end injects an intense electron beam, such as from a Marx generator or a flux compression generator, optionally with a suitable pulse-forming network, e.g. a Blumlein transmission line. The pulse has a magnitude in the range of hundred or more kilovolts and duration of about 50–150 nanoseconds. The electrons are attracted to a thin anode, such as an aluminized PET film or a stainless steel mesh, that is connected to the grounded waveguide body. The unit is surrounded by a magnet. Due to the intensity of the electron beam, many electrons pass through the anode into the region beyond it, forming a virtual cathode. The electron beam must be so intense as to exceed the space-charge-limiting current in that region, causing oscillations that generate microwaves. The frequency, efficiency and other characteristics of the emitted beam depend on the precise physical configuration and operating parameters.…

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Discussion questions

  1. Summarise the article in your own words. Which single claim would you verify first, and why?
  2. Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
  3. If two sources disagreed about one of these facts, what would you need in order to trust one over the other?

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Key claims and bibliography are generated from the same tracked claims and sources as the article page.