Determining the characteristics of thermal field emission-induced breakdown is essential for various electron emission devices, such as thermionic energy converters. In previous studies, several mathematical models were developed to determine the breakdown voltages driven by field emission under different conditions; however, complicated computations were required to solve the numerical equations. There is still no consensus on the breakdown criterion when the thermal field emission comes into play. In this work, a unified breakdown criterion for the thermal field emission-induced microdischarge is proposed based on the definition of the thermal field emission coefficient γTFE (combined with the thermionic emission coefficient γTE and field emission coefficient γFE) from the emission current. The breakdown voltages scaling with the cathode temperature and gap distance are quantified. Distinct regimes corresponding to different electron emissions and their transitions are examined with the cathode temperature and gap distance tuned across a range of values. The results from this study provide an evaluation of thermal field emission-induced breakdowns and the dominant electron emission mechanisms in distinct regimes can be straightforwardly determined from the present model.

中文翻译：

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统一热场发射驱动的微放电的击穿准则


确定热场发射诱导击穿的特性对于各种电子发射器件（例如热离子能转换器）至关重要。在以前的研究中，开发了几种数学模型来确定不同条件下场发射驱动的击穿电压;然而，需要复杂的计算来求解数值方程。当热场发射开始发挥作用时，对于击穿标准仍未达成共识。本工作基于热场发射系数γTFE（结合热电子发射系数γTE和场发射系数γFE）的定义，提出了热场发射诱导微放电的统一击穿准则。量化了随阴极温度和间隙距离成比例的击穿电压。通过在一系列值上调整阴极温度和间隙距离来检查对应于不同电子发射及其跃迁的不同状态。这项研究的结果提供了对热场发射诱导击穿的评估，并且可以从本模型中直接确定不同状态下的主要电子发射机制。