Light emission and spectroscopy characteristics of an unconventional gas spark switch

Summary form only given. The utilization of two-electrode gas spark switch is quite prevalent in pulsed power equipment as an energy controller. Its simple structure, high reliability, and long lifetime make it a relatively appropriate method applied in unconventional situations. This study concerns a two-electrode gas switch in a small airtight chamber under repetitive working condition without triggering. It is generally accepted that self-breakdown voltage is a significant index to measure the performance or lifetime of a switch. Admittedly, when the effects caused by arc are subordinate, such as the discharge current is small, merely adopting the models based on voltage or current characteristics could be accurate. However, when other factors play more important roles during the discharge process, the electrical parameters might be inadequate to describe the mechanisms. In order to gain a deeper understanding of the mechanisms in this unconventional switch, some optical diagnoses were introduced, including light emission and spectroscopy. In previous studies on this topic, it has been found that during the several thousand shots of the switch, arc's thermal effects, decomposition of insulation materials, and electrode erosion are all crucial to the switch's performance. Except the electrical parameters and chemical analyses, more immediate methods for the dynamic discharge process seem essential. Therefore, the light emitted by the arc plasma channel should be investigated, which reveals different kinds of information. In this study, photomultipliers (PMTs) and a spectrograph (AvaSpec-2048) were utilized to detect the light emission from the arc. The discharge pulsed current is peaking at approximately 60 kA and lasting about 70 μs. The spectrum demonstrates that more spectral lines appear when there are more shots, including some unexpected lines. The results are in accordant with the previous experimental data and could be used to explain how the decomposition of insulation materials and electrode erosion influence the breakdown process and lead to abnormal discharges.