低气压毛细管放电特性研究

利用一台毛细管快放电X射线激光装置．研究了预脉冲作用下氩气和氦气在10～120Pa压强范围内对毛细管放电的击穿特性。实验结果表明只有10～15kV放电电压才能将内径为3mm．长度为90mm的毛细管中10～120Pa的氩气击穿，同时电极表面的形态对击穿电位也有较大影响。对预、主脉冲作用下毛细管放电规律及Z箍缩过程中阻抗变化规律进行了研究，发现不同长度的氩气柱在箍缩过程中的阻抗变化趋势基本相同。不同长度、不同放电电压情况下，毛细管阻抗均达到最小值5n左右．同时电流达到峰值。该结果为在相同放电电压下．对不同长度毛细管放电获得相同的电流峰值提供了可能。

Study on Low Pressure Discharge Character of Capillary Discharge

The breakdown characteristics of capillary discharge are measured in Ar and He gases within the pressure range from 120 Pa to 10 Pa, which is the range for lasing by capillary discharge. The experimental results indicate that at least ～10 kV of discharge voltage is required for the breakdown of gas filled in a capillary of 3 mm in diameter and 90 mm in length, which is much higher than that needed in parallel electrode system. The breakdown voltage is also greatly affected by the surface shape of electrode in low pressure. Studies show that the impedances of capillary for different lengths of gas column under the different discharge voltages represent the same character. The impedances reach the same minimum of ～5 Ω when the discharge currents reach the peak value, which makes it possible to obtain the same current peak value at the same discharge voltage for different lengths of capillary.