Operation of a long-pulse relativistic magnetron in a phase-locking system

Successful injection-locking of relativistic magnetrons requires frequency stable microwave output with pulse lengths longer than the phase-locking time. We report the major experimental results from our stable and long-pulse relativistic magnetron system designed to address important issues relevant to the realization of injection-locking. Long voltage pulse operation 1js) with good stability was achieved and relatively long (250 ns) RF pulses at 5 MW output power level were generated. These pulses exceed the theoretical locking time for a 1 MW injected power source. The magnetron operates in S-band (3. 66 GHz) and is driven by a modulator which operates either at 700 kV/ 700 A or 250 kV/ 1. 7 kA. The stability of the narrow band microwave frequency is better than 3 parts in 1000. Possible RF pulse-shortening mechanisms are studied. 1.