The cathode-sheath region of a discharge in atmospheric pressure air with a flat copper cathode is numerically investigated by using a simple fluid model that takes into account non-local ionization. The effects of the cathode temperature are considered. Results are obtained in a wide current density range of 1–10² A/cm², which spans from normal glow discharge, through abnormal glow discharge, up to the early stages of the arcing transition. It is shown that the glow-to-arc transition arises from a field-emission instability at the cathode when the current density is larger than ∼10 A/cm², i.e., when the cathode field exceeds a critical value of about 45 V/μm for the conditions considered. It is also shown that the cathode temperature significantly influences the cathode-sheath region. The proposed model is validated by comparing the numerical results with available experimental data.

中文翻译：

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场发射持续大气压放电的阴极鞘模型

通过使用考虑了非局部电离的简单流体模型，在大气压力下使用扁平铜阴极对阴极的放电鞘区进行了数值研究。考虑阴极温度的影响。在1–10 ² A / cm ²的宽电流密度范围内可获得结果，其范围从正常的辉光放电到异常的辉光放电，一直到电弧过渡的早期。结果表明，当电流密度大于约10 A / cm ^2时，即当阴极场超过约45 V / cm的临界值时，辉光弧过渡是由阴极处的场发射不稳定性引起的。μm为所考虑的条件。还显示出阴极温度显着影响阴极-鞘区域。通过将数值结果与可用的实验数据进行比较，对所提出的模型进行了验证。