Investigation of Hot Cathode and Hollow Anode of Argon Glow Discharge Plasma

Abstract

Hot cathode and hollow anode argon DC glow discharge plasma at different pressures of (0.04, 0.05, 0.06, 0.07, 0.09, 0.2, 0.4, and 0.8 mbar) has been investigated. The experiments were carried out under the influence of pressure and filament cathode current on voltage-current characteristics of glow discharge and its breakdown voltage. Plasma parameters have been measured and obtained using single probe method at fixed discharge current (I d =1.88 mA) and hollow anode diameter. A computer MATLAB program is performed for this purpose. It was shown that the discharge voltage-current characteristics curve has a positive resistance and represents an abnormal glow region at pressure (0.04 and 0.06) mbar for different filament current. The breakdown voltage increases as the filament current is increased. In different pressure, electron temperature shows different behavior with increasing filament current. Electron density varies nearly inversely with the filament current, but it is increase due to increase of pressure from (1 to 3 mbar), then tends to decrease for the higher pressure. There are two groups of electrons according to the two peaks of (EEDFs), and the peaks amplitude decrease, with the increases of both filament current and gas pressure.

Effect of Pressure and Hot Filament Cathode on Some Plasma Parameters of Hollow Anode Argon Glow Discharge Plasma

“…Fig. 10", show that the increasing gas pressure from 0.05 to 0.09 mbar causes decreasing ion temperature due to decreasing electron temperature and then tends to increase according to increase of electron temperature [10]. Electron Energy distribution function (EEDFs) is one of the most important property for fusion and processing plasma.…”

“…The plots indicated that (EEDFs) decrease with the increasing filament current, the amount of high energy electrons decreases. The latter effect is attributed to enhancing the negative space charge near the anode [10]. Later the (EEDFs) are plotted against the gas pressure for different filament current as shown in " fig.…”

“…It appears from figure there are a few amount of high energy electrons at low pressure and the amount of low energy electrons increase with increasing pressure approaching to 0.09 mbar, then the amount of high energy electrons tends to decease according to further increasing gas pressure, since the electron can transfer almost all its energy to the heavy particle due to inelastic collisions creating an energetic plasma species [12]. Therefore it can be concluded that there are three groups of electrons: group of high energy electrons at low, group of high pressures and group of low energy electrons at medium pressure investigated [10].…”

“…The x-y recorder (oscilloscope) traces the (I p -V p ) characteristic of the probes, and the voltage on the probes is recorded on the x-axis, while the current through the probes is recorded on the y-axis, as the voltage drop across the resistance of value (10 KΩ). More details about the equipment and experimental work are reported by [10]. The latter, means that increasing emitted electrons from the filament enhances the negative space charge near the anode and consequently the discharge voltage increases as well as its resistance [11].…”

“…The objective of the current study is a review article and an extension to the published paper [10], to investigate experimentally the effect of filament current and argon gas pressure on some characteristics of glow discharge as well as upon additional plasma parameters, ion temperature, degree of ionization and electron energy distribution functions at a fixed discharge current (I d =1.88mA) and diameter of hollow anode at different working gas pressure.…”