Study on Multipactor Mechanism in a Two-Sided Dielectric-Loaded Rectangular Waveguide

This study presents a novel saturation mechanism for the evolution of the multipactor effect in a rectangular waveguide loaded with dielectric on both the top and bottom sides. By carrying out in-house developed Monte Carlo simulations, it is observed that secondary electron emission and dielectric charging processes occur asynchronously in each multipactor zone due to an inhomogeneous radio frequency (RF) electric field. A nonuniform electrostatic field generated by the dielectric charging breaks the secondary electrons' resonant motion, resulting in a steady state when the ratio of the local electrostatic field intensity to the corresponding RF electric field intensity reaches a fixed value. Thereafter, dielectric charging in distinct multipactor zones exhibits identical oscillation during each RF period. It is worth emphasizing that dielectric charging within the third-order multipactor zone can initiate the emission of secondary electrons in nearby multipactor-free zones. This process disrupts the weak steady state in the hybrid-resonant multipactor zone, setting off a second avalanche that ultimately leads to saturation. Subsequently, dielectric charging within multipactor-free zones induces dense electrons to migrate toward high RF electric field zones, resulting in the dispersion of the electron cloud within the third-order multipactor zone.