We present and analyze characteristics of the runaway electron flow in a high-voltage (the voltage rise rate of up to 1.5 MV/ns) air-filled electrode gap with a strongly nonuniform electric field. It is demonstrated that such a flow contains a high-energy electron component of duration not more than 10 ps. According to numerical simulations, runaway electron generation/termination is governed by impact ionization of the gas near the cathode and switching on/off a critical (sufficient for electrons to run away) electric field at the boundary of the expanding cathode plasma. The corresponding characteristic time estimated to be 2–3 ps is defined by the ionization rate at a critical field.We present and analyze characteristics of the runaway electron flow in a high-voltage (the voltage rise rate of up to 1.5 MV/ns) air-filled electrode gap with a strongly nonuniform electric field. It is demonstrated that such a flow contains a high-energy electron component of duration not more than 10 ps. According to numerical simulations, runaway electron generation/termination is governed by impact ionization of the gas near the cathode and switching on/off a critical (sufficient for electrons to run away) electric field at the boundary of the expanding cathode plasma. The corresponding characteristic time estimated to be 2–3 ps is defined by the ionization rate at a critical field.

中文翻译：

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空气电极间隙中失控的电子流有多短？

我们展示并分析了具有强非均匀电场的高压（电压上升率高达 1.5 MV/ns）充气电极间隙中失控电子流的特性。证明这种流包含持续时间不超过 10 ps 的高能电子分量。根据数值模拟，失控电子的产生/终止由阴极附近气体的碰撞电离和在膨胀的阴极等离子体边界处打开/关闭临界（足以使电子逃逸）电场控制。对应的特征时间估计为2-3 ps，由临界场的电离率定义。我们呈现并分析了高压下失控电子流的特征（电压上升率高达1. 5 MV/ns) 具有强非均匀电场的充气电极间隙。证明这种流包含持续时间不超过 10 ps 的高能电子分量。根据数值模拟，失控电子的产生/终止由阴极附近气体的碰撞电离和在膨胀的阴极等离子体边界处打开/关闭临界（足以使电子逃逸）电场控制。估计为 2-3 ps 的相应特征时间由临界场的电离率定义。失控电子的产生/终止由阴极附近气体的碰撞电离和在膨胀的阴极等离子体边界处打开/关闭临界（足以使电子逃逸）电场控制。估计为 2-3 ps 的相应特征时间由临界场的电离率定义。失控电子的产生/终止由阴极附近气体的碰撞电离和在膨胀的阴极等离子体边界处打开/关闭临界（足以使电子逃逸）电场控制。估计为 2-3 ps 的相应特征时间由临界场的电离率定义。