Three-dimensional particle-in-cell simulation study of a relativistic magnetron

The A6 (six cavity) magnetron operated at relativistic voltages is investig ated using three-dimensional particle-in-cell simulation. Previous experime nts [A. Palevsky and G. Bekefi, Phys. Fluids 22, 986 (1979)] are repeated n umerically for the purpose of ascertaining fidelity of code results in addi tion to obtaining insight into magnetron operation at high voltage. Simulat ions produce all qualitative behavior observed in experiments, with good qu antitative agreement in most cases. This numerical study also reveals detai ls concerning mode control, the cause and prevention of leakage current, an d voltage scaling in the A6. It is shown that: (1) leakage current substant ially reduces efficiency, (2) elimination of leakage current using cathode endcaps substantially increases efficiency, and (3) the functional dependen ce of operating voltage on applied magnetic field may depart from conventio nal scaling at very high voltage. (C) 1999 American Institute of Physics. [ S1070-664X(99)01902-3].