Vacuum arcing poses significant challenges for high-field vacuum devices, underscoring the importance of understanding it for their efficient design. A detailed description of the physical mechanisms involved in vacuum arcing is yet to be achieved, despite extensive research. In this work, we further develop the modeling of the physical processes involved in the initiation of vacuum arcing, starting from field emission and leading to plasma onset. Our model concurrently combines particle-in-cell with Monte Carlo collisions (PIC-MCC) simulations of plasma processes with finite element-based calculations of electron emission and the associated thermal effects. Including the processes of evaporation, impact ionization and direct field ionization allowed us to observe the dynamics of plasma buildup from an initially cold cathode surface. We simulated a static nanotip at various local fields to study the thresholds for thermal runaway and plasma initiation, identifying the significance of various interactions. We found that direct field ionization of neutrals has a significant effect at high fields on the order of 10 GV/m. Furthermore, we find that cathode surface interactions such as evaporation, sputtering and bombardment heating play a major role in the initiation of vacuum arcs. Consequently, the inclusion of these interactions in vacuum arc simulations is imperative.

中文翻译：

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通过耦合发射、加热和等离子体过程来模拟真空起弧

真空电弧给高场真空设备带来了重大挑战，强调了理解它对于高效设计的重要性。尽管进行了广泛的研究，但真空电弧所涉及的物理机制的详细描述尚未实现。在这项工作中，我们进一步开发了真空电弧引发所涉及的物理过程的建模，从场发射开始直至等离子体开始。我们的模型同时将等离子体过程的粒子内粒子与蒙特卡罗碰撞 (PIC-MCC) 模拟与电子发射和相关热效应的基于有限元的计算相结合。包括蒸发、碰撞电离和直接场电离过程，使我们能够观察从最初冷的阴极表面形成等离子体的动态。我们在各个局部场模拟了静态纳米尖端，以研究热失控和等离子体引发的阈值，确定各种相互作用的重要性。我们发现中性粒子的直接场电离在 10 GV/m 量级的高场下具有显着影响。此外，我们发现蒸发、溅射和轰击加热等阴极表面相互作用在真空电弧的引发中起着重要作用。因此，必须将这些相互作用纳入真空电弧模拟中。