Channel resistance characteristics study for underwater plasma discharge

When two electrodes are stressed in water with high voltage, a highly conductive discharge channel will be created. During the discharge, the channel resistance is time variant, ranging from a few Ohms at the beginning to only a few milliohms in intermediate phase, and back to its original value in the end. With the underwater plasma discharging phenomena in process, several types of energy are produced, including the bubble internal energy, the bubble pulse energy, the radiation energy and the shockwave energy. The composition of these types of energy have been calculated and analyzed. Based on the obtained energy distribution and according to Energy Balance Theory, a model of the time variant discharge channel resistance was proposed. The model had been validated by using the experimentally measured discharge current and shockwave pressure data in our underwater plasma test platform. The model results were also coincident with previous related works. At last, some recommendations were proposed on improving the energy conversion efficiency.