In this paper, a Monte Carlo simulation method was proposed to investigate the initial cascade process of low-pressure microwave air breakdown. Calculations were performed by tracing electrons only, with the assumption that space charge was negligible. Two main electron generation mechanisms, electron-impact ionization and surface secondary electron emission (SEE), were introduced to simulate the initial breakdown phase more realistically. Detailed investigations were performed in a parallel plate waveguide operating at 9.4 GHz with pressures ranging from 0.2 Torr to 100 Torr. The results confirm that microwave breakdown is controlled by impact ionization at high pressures. However, as the gas pressure decreases, secondary electron emissions prevail against electron-neutral collisions, which leads to the sensitivity of the breakdown field on SEE. The threshold breakdown electric field obtained by the Monte Carlo method has been compared with experimental results, showing good agreement in the case where an appropriate secondary electron emission model is given. The developed Monte Carlo method provides an inexpensive way to determine the breakdown field and can be further applied to other microwave components of interest.

中文翻译：

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考虑电子-表面相互作用的平行板中微波空气击穿的蒙特卡罗模拟

本文提出了一种蒙特卡罗模拟方法来研究低压微波空气击穿的初始级联过程。计算仅通过追踪电子进行，假设空间电荷可以忽略不计。引入了两种主要的电子生成机制，即电子碰撞电离和表面二次电子发射 (SEE)，以更真实地模拟初始击穿阶段。在 9.4 GHz 的平行板波导中进行了详细的研究，压力范围从 0.2 Torr 到 100 Torr。结果证实微波击穿是由高压碰撞电离控制的。然而，随着气压的降低，二次电子发射会对抗电子-中性碰撞，这导致击穿场对 SEE 的敏感性。蒙特卡罗方法得到的阈值击穿电场与实验结果进行了比较，在给出合适的二次电子发射模型的情况下显示出良好的一致性。开发的蒙特卡罗方法提供了一种确定击穿场的廉价方法，并可进一步应用于其他感兴趣的微波组件。