What is glow discharge?

Glow discharge is a self-excited conductive phenomenon in thin gas. Its physical mechanism is: the discharge tube poles of the voltage increased to a certain value, the residual positive ions in the thin gas is accelerated by the electric field, to obtain a large enough kinetic energy to hit the cathode, resulting in secondary electrons, through the cluster shooting process to form a large number of charged particles, so that the gas conductive. Glow discharge is characterized by small current density, temperature is not high, the discharge tube produces light and dark light areas, the gas inside the tube is different, the color of the glow is also different. Normal glow discharge, the voltage between the poles of the discharge tube does not change with the current. The luminescence effect of glow discharge is used to manufacture neon lamps, fluorescent lamps and other light sources, and its voltage regulator characteristics can be used to make voltage regulator tubes (e.g., neon regulator tubes). A self-sustained discharge of a gas at low atmospheric pressure. Apply voltage to the glass cylindrical discharge tube at both ends, when the pressure is in the range of 1 ~ 0.1 Torr, the electrons escaping from the cathode in the gas collision ionization and photoionization, at this time, most of the area of the discharge tube are showing diffuse glow, the color varies depending on the gas, so it is called glow discharge. Glow discharge and dark discharge and arc discharge together constitute a continuous change of the three basic forms of discharge.

In 1831~1835, M. Faraday discovered the phenomenon of glow discharge and Faraday's dark region during the study of low-pressure discharges, and in 1858, J. Prückel discovered cathode rays during the study of glow discharges at 1/100 Torr, which became the forerunner of the study of particle radiation and atomic physics at the end of the 19th century.

Glow discharge has subnormal glow and anomalous glow two transitional stages, the entire channel of the discharge consists of different brightness intervals, that is, from the cathode surface, in order: ① Astron dark zone; ② cathode light layer; ③ cathode dark zone (Crooks dark zone); ④ negative glow zone; ⑤ Faraday dark zone; ⑥ positive columns; ⑦ anode dark zone; ⑧ anode light layer. Among them, the negative glow region, Faraday dark region and positive column region as the main body. These light zones are the result of space ionization process and charge distribution, and are related to the gas category, gas pressure, electrode materials and other factors, which can be explained from the discharge theory. During the glow discharge, more heterogeneous space charges are gathered near the two electrodes, thus creating significant potential landings, called cathodic and anodic pressure drops, respectively. The cathodic voltage drop is the main component of the potential drop between the electrodes, and the voltage between the two electrodes does not change with the current during normal glow discharge, i.e., it has the property of voltage stabilization.

The main applications of glow discharge are: ① the use of its luminous effect (such as neon lights) and normal glow discharge voltage regulator characteristics (such as neon regulator). ② the use of glow discharge of the positive column area of the characteristics of the laser, the manufacture of helium-neon lasers.

Dalian Jieman Technology Co., Ltd. utilizes a self-developed and produced high-voltage AC power supply model JMAC-P10-400mA, utilizing a high frequency of 20kHz, and after applying it to the load of the glass jar tube body, the discharge phenomenon shown in the following figure was obtained: