Pulse electrical discharges in water and their applications

Partial electrical discharges in a water solution as a function of conducti vity have been studied experimentally. Using needle-plate electrodes it has been demonstrated that the discharge evolves in two phases. During the fir st streamer-like phase, the discharge propagated with a velocity of 10(6) c m/s, while during the second arc-like phase the length of the discharge rem ained almost constant although the current still increased. Higher solution conductivity resulted in the generation of shorter channels, in larger dis charge current, and in a higher plasma electron density. Degradation of phe nol by the discharge has also been demonstrated. A special metallic electro de covered by a thin layer of porous ceramic has been developed and used fo r generation of a multichannel discharge. At comparable solution conductivi ty the ceramic-coated electrode produced plasma with very similar parameter s as the needle-plate electrode configuration. Generation of strong focused shock waves by the multichannel discharge in a highly conductive solution has also been demonstrated. (C) 2001 American Institute of Physics.