PROJECT TITLE :

Penetration of Gas Discharge Through the Gas–Liquid Interface Into the Bulk Volume of Conductive Aqueous Solution

ABSTRACT:

Gas dischargeplasma generated above the surface of conductive aqueous solutions in an exceedingly glass capillary was used to review penetration of the discharge from the bubble (imitated by the space on top of meniscus of liquid surface within the capillary) into the bulk liquid. The experiments were conducted at both polarities with a high-voltage needle electrode placed on top of the liquid surface. Totally different aqueous solutions were examined (distilled water, conductive saline solutions). High-speed shadowgraphy was used as the main diagnostic tool for the study of the disturbances at the plasma–liquid interface. It's been found that electric field just beneath the liquid surface and therefore the liquid/plasma conductivity ratio have a decisive impact on the event of plasma–liquid interface instabilities. Experiments with negative electrode on top of the liquid surface showed that this surface in the place of the most important current density recedes. This receding is caused by the reaction pressure ensuing from liquid evaporation. So, long cavities with plasma within will be shaped. The cavity elongation speed is of the order of , and it depends on current density. The liquid surface remains swish, when the liquid conductivity is larger than the conductivity of adjacent plasma. In the alternative case, if the liquid conductivity is smaller than the conductivity of adjacent plasma, the distribution of current density on the plasma–liquid boundary is unstable: any initial surface disturbance boosts this density during a native surface valley simultaneously causing a detriment of the surrounding current density. Consequent stronger liquid evaporation within the valley causes its deepening, and hence, next enhancement of the inhomogeneity of current density distribution. The dips created during this means subsequently rework into negative streamers, when electric field - arger than appears near the liquid surface. Experiments with the positive electrode on top of the liquid surface significantly showed more intense liquid evaporation than the experiments with the negative one—beneath otherwise the same conditions. Therefore, elongation speed of the gas cavities is also significantly higher. The development of spikes on liquid surface is additionally smitten by the liquid conductivity. However, electric field larger than near the liquid surface is important for the development of positive streamers.