Statistical Computation for Multipactors in Arbitrary Microwave Devices

Multipactors are avalanches of secondary electrons occurred in high-power vacuum microwave devices. Accurate prediction of their occurrences is challenging, especially for devices with complex geometric cavities under complex excitations. In this article, a generalized statistical theory is derived for predicting multipactors occurred in arbitrary metallic cavities under arbitrary excitations. Its computation burden is independent on the number of electrons, enabling investigations for dynamic evolutions of multipactors even in the presence of huge amount of avalanching electrons. Exampled with coaxial, rectangular, and ridged rectangular waveguides and excited with sinusoidal, multicarrier, and wideband radar signals, dynamic electron populations and breakdown levels were computed. While the obtained results agree well with previously reported experiments and particle-in-cell simulations, these results also explain three special phenomena occurred during multipactors, verifying the validity and accuracy of the proposed solution.