Low-current discharge plasma jets in a gas flow. Application of plasma jets

Abstract

The paper describes the results of investigations of low-current discharges in a gas flow at atmospheric pressure. The primary focus is on glow discharges in coaxial plasmatrons and the so-called gliding arc. Such discharges are typically used for obtaining a plasma jet at the exit of the electrode system. The jet contains active chemical species playing an important role in various applications of the discharge. Plasmaassisted combustion and oxidation of hydrocarbon fuels is also considered. Besides, the applications of plasma jet for modification of surfaces and for use in biology and medicine are discussed.

Triggering of cold-cathode thyratron in electric circuit with grounded grid

“…4,24 At a later time, due to explosive emission process, 4,24-29 the arc cathode spot is initiated and glow-to-arc transition occurs. 4,[30][31][32][33][34] Note that the other method of the switch triggering depends on the so called electric circuit of classical thyratron. 5,6 In this circuit, the only grounded electrode is the cathode C 1 .…”

“…The reason is that the first stage of the discharge development is determined by discharging the capacitance of the cable which connects the trigger unit with the trigger generator. 30,33 This capacitance is about 100 pF. Thereafter, the current waveform is determined by the inductance of the exit circuit of the trigger generator.…”

Simulation of nonstationary phenomena in atmospheric-pressure glow discharge

“…In recent years, interest in atmospheric-pressure glow discharges, including those in a gas flow, has increased significantly [1][2][3][4][5][6][7][8][9]. When the glow discharge is concerned, it is usually implied that it is a low-pressure discharge, which is stationary by its nature.…”

“…Glow discharges in large volumes or at atmospheric pressure can operate only in the pulsed mode [10][11][12], because, after some time (about 1 μs or less), such a discharge transforms into a spark. This process is usually initiated by explosive emission instability in the cathode sheath and the formation of a cathode spot [1,10,[13][14][15][16][17][18][19]. Nevertheless, it is still possible to implement stationary glow discharges or discharges with random short-term transitions into the spark mode at atmospheric pressure [1,[20][21][22].…”

“…This process is usually initiated by explosive emission instability in the cathode sheath and the formation of a cathode spot [1,10,[13][14][15][16][17][18][19]. Nevertheless, it is still possible to implement stationary glow discharges or discharges with random short-term transitions into the spark mode at atmospheric pressure [1,[20][21][22]. The necessary conditions for this are a sufficiently low discharge current (not exceeding several fractions of ampere) and a small transverse size of the plasma column (as a rule, less than 1 mm).…”