Veske Mihkel, Kyritsakis Andreas, Djurabekova Flyura, Sjobak Kyrre Ness, Aabloo Alvo, Zadin Vahur
Department of Physics and Helsinki Institute of Physics, University of Helsinki, P.O. Box 43 (Pietari Kalmin katu 2), 00014 Helsinki, Finland.
CERN, Geneva, Switzerland and Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo, Norway.
Phys Rev E. 2020 May;101(5-1):053307. doi: 10.1103/PhysRevE.101.053307.
We propose a method to directly couple molecular dynamics, the finite element method, and particle-in-cell techniques to simulate metal surface response to high electric fields. We use this method to simulate the evolution of a field-emitting tip under thermal runaway by fully including the three-dimensional space-charge effects. We also present a comparison of the runaway process between two tip geometries of different widths. The results show with high statistical significance that in the case of sufficiently narrow field emitters, the thermal runaway occurs in cycles where intensive neutral evaporation alternates with cooling periods. The comparison with previous works shows that the evaporation rate in the regime of intensive evaporation is sufficient to ignite a plasma arc above the simulated field emitters.
我们提出了一种直接耦合分子动力学、有限元方法和细胞粒子技术的方法，以模拟金属表面对高电场的响应。我们使用这种方法通过充分考虑三维空间电荷效应来模拟热逃逸下场发射尖端的演化。我们还比较了两种不同宽度尖端几何形状的逃逸过程。结果显示，在统计上具有高度显著性，对于足够窄的场发射体，热逃逸以循环方式发生，其中强烈的中性蒸发与冷却期交替出现。与先前工作的比较表明，在强烈蒸发阶段的蒸发速率足以在模拟的场发射体上方点燃等离子体电弧。
