Similarity laws for glow discharges with cathodes of metal and an electrolyte

Abstract

The pressure dependence of the cathodic current density in the case of an electrolyte and a metal cathode glow discharge operating in air and helium atmospheres was investigated. In all cases, at pressures above 100-200 mbar, violation of the similarity law was observed, which was attributed to the occurrence of the dissociative recombination of molecular ions of the applied gases (O, and ). Taking into consideration this process, the relation was deducted, which was found to be in accordance with experimental data. In the case of an electrolyte cathode this relation was found to be valid also at low pressures.

Surface-time enlargement law for gas breakdown

“…Theoretical curves showing the dependence of the variation coefficient on the geometrical enlargement factor (1 -three-parameter Weibull distribution, 2 -two-parameter Weibull distribution, 3 -double-exponential distribution) and the corresponding experimentally obtained values of the breakdown voltage random variable, for the case when breakdown may occur either at the leading or at the trailing edge of the pulse (radial electric field, 1 bar SF 6 gas pressure, r i = 4 mm, r a = 18 mm, l = 20 mm). Figure 6 shows the dependence of the variation coefficient on the time enlargement factor for the twoand three-parameter Weibull, double-exponential and normal distributions, determined from expressions (20), (21) and (19) respectively, along with the corresponding experimentally obtained values of the breakdown time random variable, in the homogenous electric field. Comparing theoretical and experimental results in Figure 6 it can be assumed that, in this case, breakdown time random variable follows the normal distribution, although the possibility that it belongs to the two-parameter Weibull or the double-exponential distribution cannot be excluded either.…”

“…For practical reasons, the enlargement law has usually been reduced to the validity of the Paschen's law [13][14][15], applicable only to homogeneous electric-field configurations and dc voltage, which is the most Manuscript received on 23 July 2007, in final form 6 February 2008. common case in high-voltage device design [16,17]. Some researches expanded the testing (mainly experimental) of the enlargement law validity toward parameters of gas electrical breakdown, such as electrode material, voltage polarity, electrode surface topography, and discharge mechanisms [18,19]. These investigations mainly lead to the same conclusion that it is impossible to make a connection between the influence of the stated parameters and the enlargement law.…”

Roles of electrode material and geometry in liquid sampling-atmospheric pressure glow discharge (LS-APGD) microplasma emission spectroscopy

“…Very different from the ELCAD-type devices where cathodic sputtering is proposed as the means of sample introduction [5,6,9], the ability to operate the LS-APGD solution as either the cathode or anode suggests that it is the thermal energy generated by charged particles crossing the solution/vapor interface that leads to vaporization. The heat generated is proportional to the discharge current, leading to greater vaporization rates.…”

“…Cserfalvi and co-workers first introduced the electrolyte-cathode discharge (ELCAD) for OES analysis in the 1990's [6][7][8][9]. This device operates by striking a glow discharge at atmospheric pressure between an anode (metal rod) and an electrolyte solution (pH 1-3, containing the analyte) acting as the cathode.…”

Spectrochemical Analysis by Using Discharge Devices with Solution Electrodes

“…Flow rates of 8-10 mL/min have been used in most designs. 17,18,[21][22][23] Three more-recent devices, however, operate at flow rates of 2.5 and 3.5 mL/min. 16,19,24 The common feature among these three units is their small cathode size (relative to earlier configurations); not surprisingly, the system working at the lowest flow rate also has the smallest cathode.…”