Instabilities of prebreakdown currents in vacuum I: late breakdowns
Instabilities of prebreakdown currents in vacuum I: late breakdowns
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真空中预击穿电流的不稳定性 I：晚期击穿
DOI：
10.1088/0022-3727/32/19/310
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
Gerd Düning
中科院分区：
文献类型：
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作者：
Burkhard Jüttner;Manfred Lindmayer;Gerd Düning
实验研究了延伸金属电极间的预击穿电子发射，时间分辨率为100ns。切换到更高的排放水平是可以观察到的，并且可能由机械冲击引起。这被发现类似于自发开关效应。电流跳变的基本时间常数为1-3µs，而整个开关过程持续时间长达40 ms，从而排除了宏观粒子的影响。发现击穿电压与发射水平相关。因此，开启电子发射可以解释延迟时间为bbb1ms的击穿。在邻近电弧间隙产生的金属蒸气等离子体沉积时，发现时间更长。在某些情况下，会发生持续数秒的瞬态辐射增加。因此，在真空断流器中，电流为零后的后期击穿可能是由没有粒子冲击的机械冲击引起的，也可能是由阴极残余蒸气的沉积引起的。
Prebreakdown electron emission between extended metal electrodes is experimentally studied with time resolution of 100 ns. Switching to higher emission levels is observed and could be provoked by mechanical shocks. This is found to be analogous to spontaneous switching effects. Elementary time constants of current jumps are 1-3 µs while the whole switching process lasts up to 40 ms, thus ruling out impact of macroparticles. The breakdown voltage is found to be correlated with the emission level. Therefore, switching on electron emission can explain breakdowns with delay times >1 ms. Still longer times are found at the deposition of metal vapour plasma originating from neighbouring arc gaps. In some cases, transient increases of the emission occur that last several seconds. Therefore, in vacuum interrupters late breakdowns after current zero can be caused by mechanical shocks without particle impact and also by deposition of residual vapour at the cathode.