Temporal study of long-pulse relativistic magnetron operation

A streak camera was used to make observations of apparent plasma motion in the interaction space of an A6 relativistic magnetron with an explosive emission cathode. The anode plasma luminosity velocity was measured to be 0.8 cm/μs, comparable with the gap closure velocity, which was indirectly measured to be 1.0-1.6 cm/μs, depending upon the magnetic field. The gap closure velocity appeared to be independent of the microwave oscillation. Long-pulse operation (hundreds of nanoseconds) as a function of the magnetron-modulator interaction is also presented. At 250 kV the A6 emitted microwave pulses out of a single resonator for up to 250 ns in duration, with peak power up to 90 MW and a characteristic single-spike pulse length of 150 ns