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Simulation studies of interface dynamics of secondary electron yield in perforated media

The Secondary Electron Yield (SEY) is one of the key factors of multipactor, which remains a serious potential risk for high power vacuum applications. In this paper, the SEY and electron dynamics at different porous medium interfaces have been analyzed numerically for multipactor simulation and suppression. Due to the existence of an RF field, accumulated charge field, and external bias magnetic field, the previous electron trajectory tracking method in porous metal surfaces is not applicable. The real electromagnetic field distributions in porous medium, including metal and dielectric, are obtained theoretically and numerically for the calculation of electron motion. Based on the Monte Carlo simulation method, a novel numerical algorithm is proposed for the SEY calculation in porous medium. Simulation results show that SEYs of the porous dielectric perforated with cylindrical pores are correctly calculated and match well with experiments. It is demonstrated that the SEY at the porous interface is not only determined by electron motions but is also affected by the geometry structures of micro-pores. Different from the metal surface, the SEY at the porous dielectric interface increases when the width-to-depth ratio of micro-pores is greater than 1. The SEY reduces only since the depth of micro-pores is larger than lateral dimensions. As the depth gets much larger than the width, the “electron trapping” effect becomes remarkable and the SEY reduces considerably, which is promising for multipactor-free design in high power applications.The Secondary Electron Yield (SEY) is one of the key factors of multipactor, which remains a serious potential risk for high power vacuum applications. In this paper, the SEY and electron dynamics at different porous medium interfaces have been analyzed numerically for multipactor simulation and suppression. Due to the existence of an RF field, accumulated charge field, and external bias magnetic field, the previous electron trajectory tracking method in porous metal surfaces is not applicable. The real electromagnetic field distributions in porous medium, including metal and dielectric, are obtained theoretically and numerically for the calculation of electron motion. Based on the Monte Carlo simulation method, a novel numerical algorithm is proposed for the SEY calculation in porous medium. Simulation results show that SEYs of the porous dielectric perforated with cylindrical pores are correctly calculated and match well with experiments. It is demonstrated that the SEY at the porous interface is not on...