Theoretic analysis and numerical simulation of metal two-sided multipactor discharge

In most HPM devices, multipactor discharge causes gas ionization and breakdown, and yields plasmas on surface. It would induce the shortening of output HPM pulses, and seriously deteoriate the performance of HPM devices. The metal two-sided multipactor discharge was theoretically analyzed and numerically simulated. Firstly, the dynamics equations, resonant phase, focusing phase, collision potential were introduced and analyzed in theory. Depending on material characteristic of secondary emission, the susceptibility curve of two-sided multipactor discharge was discussed. Secondly, using Monte Carlo method simulating the initial emission energy and angle, the susceptibility curve of two-sided multipactor discharge was studied and discussed compared with the theoretic results. And the relationship was given between the number of secondary electrons and time. Finally, the secondary emission boundary module was added in NEPTUNE code (a 3D fully electromagnetic and PIC code) successfully. The two-sided multipactor discharge course on copper surface was simulated by NEPTUNE code, and the physical image of multipactor discharge and the relationship between the number of secondary electrons and time were visualized. The simulated results agreed with the theoretic and numerical results well. In addition, the saturation of multipactor discharge induced by space-charge limit was also given and discussed.