Measurement of plasma-neutralized super-vacuum currents in a gyrotron configuration

Experimental results are reported on the transport of an electron beam with current in excess of the vacuum space‐charge‐limited value, in a configuration directly applicable to gyrotron oscillators. The vacuum space‐charge limit is circumvented by the introduction of a neutralizing background plasma which is produced by an array of four plasma guns placed immediately downstream of the electron gun anode.