Plasmas created by electrical discharges in liquids and their applications to electrosurgery

Electrical discharges in conducting saline solutions can be used to produce localized atmospheric pressure glow discharge plasmas that are used effectively to remove and treat biological tissue such as cartilage. This presentation will focus on the basic physics of radiofrequency discharges in liquids, the formation of thin vapor layers, and the properties of plasmas formed in the vapor layer. Spectroscopic and other optical measurements, as well as electrical current and voltage measurements can be used to deduce many of the plasma properties. The molecular physics of water vapor and its fragments are particularly important for understanding many of the optical features. Several distinctly different modeling techniques (finite element coupled physics, chemical kinetics, and molecular spectroscopy) unify our understanding of the experimental observations. Numerous medical devices utilizing these discharges have been developed and a brief movie clip will illustrate one of the applications.