Research on high density plasma of pulsed discharge in water

Pulsed discharge in water has been used for underwater intense low-frequency sound source, water purification, sterilization, lithotripsy, and so on. But up to now, it still has not been used widely. One of the main reasons is that the plasma of pulsed discharge in water (PPDW) has not been adequately studied. The pressure of PPDW can be higher than 10/sup 9/Pa, but its temperature is only several ev. Under such conditions, the ionization ratio of atom H and O is raised remarkably for the pressing effect. On the other hand, the coulomb interaction among charged particles and the perturbation of energy eigenvalue of atoms should not be neglected. So if ideal gas state-equation is used to treat PPDW, a large error will be produced. In this paper, a novel model is presented in which three kinds of effect mentioned above and mass exchange between PPDW and water are included. According to the model, when discharge circuit´s parameters and the distance between two electrodes are given, the time-dependent pressure P/sub in/(t), temperature T(t) and particle density n(t) of PPDW are calculated numerically. The time-dependent pressure P/sub r/(t) at the place of r from the electrodes is calculated numerically too, it shows good agreement with the experiment results.