Growth of arc in high-pressure, pulsed glow discharge by gas density depletion

Abstract

Effects of gas density depletion on arc formation of high-pressure, pulsed glow discharge have been investigated by eliminating the other factors which may affect the discharge stability, such as shock waves, residual ions, electrode heating, and discharge products. The gas density depletion has been simulated by utilizing a subsonic gas flow between the curved electrodes combined with a convergent nozzle and a divergent diffuser. A comparison has been made on the discharge in the aerodynamically created gas density depletion with the second discharge in the double-pulse discharge within a stable gas. We have found that the large gas density depletion, Δρ/ρ0∼−3.6% corresponding to a pulse repetition rate (PRR) of ∼50 Hz, tends to cause an arc-like filament or an arc without the shocks, ions, electrode heating, and products. However, the second discharge in the double-pulse discharge becomes an arc in much smaller gas density depletion (Δρ/ρ0∼−1.2% corresponding to PRR ∼3 Hz). Therefore, the collapse of high-pressure, pulsed glow discharge is most likely caused by some factor other than the gas density depletion.

Effects of Supersonic Flow Channel Configuration on Pulse Discharge for Excimer Laser Excitation

“…The high-repetition-rate operation required to provide the high average power of excimer lasers is limited by various instabilities, such as shock waves (SWs), gas density depletion and discharge products [1][2][3][4][5][6] produced by excitation discharge. Therefore, a flow is commonly used to eliminate these instabilities from a discharge cavity before the next discharge begins.…”

Characteristics of Double-Pulse Discharge in Supersonic Flow for Excimer Laser Excitation

“…The shock waves #u and #d originate from the boundaries of the heated column caused by the discharge, and they propagate upstream and downstream of the heated column, respectively. It can be observed that the shock waves #u and #d, and the heated column, which contain the causes 2,13,14) of the discharge instability, such as residual ions and gas density depletion, are eliminated downstream by the supersonic flow. The origins of shock waves #u and #d at t ¼ 0 are estimated to be at x u $ À2 mm and x d $ 4 mm, respectively, and the initial width of the heated column is $6 mm.…”