Gas breakdown and its scaling law in microgaps with multiple concentric cathode protrusions

Abstract

This paper reports gas breakdown characteristics in microgaps with multiple concentric protrusions on the cathode in the transition from the Townsend to the subnormal glow discharge regime, using a two-dimensional hydrodynamic model. The effects of the protrusion aspect ratio, height, and protrusion spacing on the breakdown voltage are investigated. The results show that when the protrusion spacing is small, the shielding effect can play a more important role in the breakdown voltage rather than the protrusion aspect ratio; the breakdown voltage is more sensitive to the protrusion height and can be assessed by the shortest gap distance. Increasing the protrusion spacing decreases the shielding effect, which lowers the breakdown voltage in both low-and high-pressure regimes. It is found that the breakdown scaling law still holds in geometrically similar microgaps with multiple cathode protrusions despite the electric field distortion.

Experimental Study of Visual Corona under Aeronautic Pressure Conditions Using Low-Cost Imaging Sensors

“…Figure 2 shows the Paschen's curve for air at 20 • C based on the work of Dakin et al, which was obtained from experimental data collected from various authors. According to (1) and Figure 2, when dealing with uniform field gaps, the breakdown voltage U b becomes higher in the low-and high-pressure zones, assuming constant spacing between electrodes [14]. It is noted that for extreme levels of low pressure, i.e., under vacuum conditions, the dielectric strength increases rapidly.…”

“…The presented data are based on different pressure conditions ranging from 100 to 20 kPa, thus covering the pressures typically found in aeronautic environments, while different air gap distances are analyzed. Most of the studies refer to power lines operating at higher altitudes [11][12][13], usually below 4000 m, dealing with pressure levels different than those found in aeronautic applications, whereas many other studies are based on spark [14][15][16], glow discharges [17], or discharges in gases other than air [18]. Therefore, there are a lack of experimental studies centered on the inception of corona for aeronautic applications, and this paper makes a contribution to this area.…”

Attenuation of Microwave Radiation by Post-Anode Plasma in a Composite Grid Electrode Structure

“…It is important to note that there are a number of factors affecting the value of the breakdown voltage of the electrode structure: (1) the product of pressure and the gap length between grid anode and cathode plate [39]; (2) the selection of an optimal breakdown path of the electrode structure by discharge [50]- [53]; (3) variation of the mean free path of electrons between grid anode and cathode plate; (4) change in the energy of electrons [49]; and others. When the pressure increases, the particle density increases and the frequency of electron collisions with neutral particles increases, resulting in more collisions within the electrode gap.…”

Experimental study on the similarity of gas discharge in low-pressure Argon gaps

“…The voltage-current (V − I) characteristics of DC glow discharge plasma can be obtained either by gradually increasing the external voltage or by lowering the external resistance [3,4,28,37,[41][42][43][44][45][46][47]. External high resistance can be introduced to limit the amount of discharge current produced [47]. The operation region of glow discharge can be identified by studying the voltage-current characteristics.…”

“…In a physical system, the occurrence of hysteresis refers to the parametric dependence of a state on its history. Hysteresis is a clear sign of nonlinearity in the system [43,47]. The jump phenomenon and hysteresis in discharge current are very well known phenomena in gas discharge, due to the variation in discharge voltage [43].…”