Plasma Production by Multiphase Alternating-Current Underwater Discharge

The multiphase alternating-current (ac) voltage source ensures the formation of plasma in water by providing an efficient breakdown voltage for the electrodes connected in parallel. The voltage-driving source was composed of 3-phase transformers to supply 12-phase ac voltage and a voltage regulator to control the output voltage of the transformers. The arrangement provided the stable large-scale underwater plasma by giving the capillary electrodes in water independent powers without voltage drop due to phase difference made from the voltage source. This plasma system in a flowing water would be useful as a continuous massive water treatment for the purification, sterilization, or disinfection of objects or materials.