Electrical Discharges in Bubbled Water

Summary form only given. Electrical discharges in gas bubbles in water are investigated by applying microsecond long rectangular pulses of 10-20 kV to needle-to-plane electrodes submerged in water. Gas is bubbled into the water through the high voltage Pt needle electrode. The voltage across the electrodes and the current to the ground are measured. Electrical measurements suggest that a corona-type atmospheric-pressure discharge is ignited in the gas bubbles (composed of the bubbled gas and water vapor) without breakdown of the entire water filled electrode gap. The discharge characteristics are investigated as a function of the applied voltage, the distance between the electrodes, the bubbled gas (Ar or O₂) and gas flow rate, and the pH and conductivity of the water. Optical and electrical measurements are used to explore the corona-type and dielectric barrier type properties of the discharge. The liquid water-metal interface and the liquid water-gas interface, both play an important role in the initiation and the development of the electrical discharge in the gas bubbles