Observation of prior light emission before arcing development in a low-temperature plasma with multiple snapshot analysis

Abstract

Arcing is a ubiquitous phenomenon and a crucial issue in high-voltage applied systems, especially low-temperature plasma (LTP) engineering. Although arcing in LTPs has attracted interest due to the severe damage it can cause, its underlying mechanism has yet to be fully understood. To elucidate the arcing mechanism, this study investigated various signals conventionally used to analyze arcing such as light emission, arcing current and voltage, and background plasma potential. As a result, we found that light emission occurs as early as 0.56 μs before arcing current initiation, which is a significant indicator of the explosive development of arcing as well as other signals. We introduce an arcing inducing probe (AIP) designed to localize arcing on the tip edge along with multiple snapshot analysis since arcing occurs randomly in space and time. Analysis reveals that the prior light emission consists of sheath and tip glows from the whole AIP sheath and the AIP tip edge, respectively. Formation mechanisms of these emissions based on multiple snapshot image analysis are discussed. This light emission before arcing current initiation provides a significant clue to understanding the arcing formation mechanism and represents a new indicator for forecasting arcing in LTPs.

Initiation mechanism of arcing generated in RF capacitively coupled plasma

“…The experimental setup is similar to the authors' previous one [1]. The vacuum vessel has a diameter of 400 mm and height of 290 mm.…”

“…Arcing, also called an electrostatic discharge, flashover, and spark, is a transient high-density discharge [1,2]. It is a ubiquitous phenomenon in high-voltage and charge-accumulated systems ranging widely from ultravacuum to atmospheric pressure, including particle accelerators [3,4], spacecraft and satellites [5,6], semiconductor and display fabrication processes [7,8], and switching gears [9,10].…”

“…To overcome these challenges and figure out the physics of arcing in moderate-density plasma, we established an arcing-inducing system along with synchronized arcing diagnostics systems involving voltage and current probes for electrical analysis and an ultra-high-speed camera for light emission analysis [1]. In this previous study, we observed prior light emission before arcing current development.…”

“…Here, the term glow refers to light emission, not to be confused with glow discharge. In [1], we analyzed the light emission characteristics with the multiple snapshot method which measures light emission by each different arcing recorded at different moment, arranges all emission images in time order, and analyze time evolution characteristics. This method enables high-resolution analysis in spatial distribution but, assumes each arcing has the same evolution characteristics.…”

Determination of Plasma Potential Using an Emissive Probe with Floating Potential Method

“…Compared with other methods, the floating potential method is regarded to be more effective and convenient for measuring plasma potential due to its relatively simple system elements and capability for time-transient measurements [ 25 , 26 , 27 , 28 , 29 , 30 ]. Despite considering its long history, its underlying physics has yet to be fully understood.…”