Effects of gas density depletion on arc formation of high-pressure, pulsed
glow discharge have been investigated by eliminating the other factors whic
h may affect the discharge stability, such as shock waves, residual ions, e
lectrode heating, and discharge products. The gas density depletion has bee
n simulated by utilizing a subsonic gas flow between the curved electrodes
combined with a convergent nozzle and a divergent diffuser. A comparison ha
s been made on the discharge in the aerodynamically created gas density dep
letion with the second discharge in the double-pulse discharge within a sta
ble gas. We have found that the large gas density depletion, Delta rho/rho(
0)similar to-3.6% corresponding to a pulse repetition rate (PRR) of similar
to 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 t
he double-pulse discharge becomes an arc in much smaller gas density deplet
ion (Delta rho/rho(0)similar to-1.2% corresponding to PRR similar to 3 Hz).
Therefore, the collapse of high-pressure, pulsed glow discharge is most li
kely caused by some factor other than the gas density depletion. (C) 2000 A
merican Institute of Physics. [S0021-8979(00)06621-4].