High-power, high efficiency, injection-locked, secondary-emission magnetron

A 60-MW, 60% efficient, 35 J/pulse secondary-emission magnetron at S-band is described and experimental results from this moderate voltage (<120 kV), repetitively pulsed (10 Hz), injection locked (14-15 dB gain) device are reported. Efforts to minimize high-voltage and RF breakdown at high power are described. Results from particle-in-cell code computer simulations compare very well with the experiment when space-charge-limited emission is assumed. Several factors which can limit the power and pulse length from this magnetron, including RF and high-voltage breakdown, cathode emission, and transport heating, are discussed. By increasing the voltage, the drive power, and the magnetron length and by using a tungsten alloy anode, 120 MW should be achievable for approximately 4- mu s pulses at 130 kV, with the pulse length limited by transient heating of the anode.<
>