The relativistic multiresonator magnetron is analyzed in full cylindrical geometry, using the twohyphen;dimensional particlehyphen;inhyphen;cell simulation codemagic. Detailed comparisons are made between the simulation results and the classic experiments by Palevsky and Bekefi for the relativistic A6 magnetron configuration lsqb;Phys. Fluids22, 986 (1979)rsqb;. The computer simulations show the same dependence of microwave power on axial magnetic field as measured in the experiment. It is found that the electron flow in the preoscillation regime differs substantially from ideal Brillouin flow, and that the nonlinear regime is characterized by largehyphen;amplitude spoke formation. By analyzing a class of relativistic magnetrons for a wide range of operating voltage and axial magnetic field, it is found that the optimal microwave power exhibits an approximately cubic dependence on the applied diode voltage. Moreover, the simulations indicate that relativistic magnetrons with small aspect ratio oscillate predominantly in the pgr; mode, whereas magnetrons with large aspect ratio can oscillate in various modes which depend upon the system parameters. Finally, it is shown that a finite powerhyphen;supply impedance can strongly modify the resonance condition, thereby significantly degrading the magnetron performance.
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