Abstract—The location of hydroxyl radical (OH∗) generation in aqua plasma is investigated with the images of vapor bubbledischarge in a conductive electrolyte (saline). A comparison of the visible- and UV-ray data taken from the Na+ ∗ and radical OH∗ reveals that Na+ ∗ is generated in both volume and surface of bubble while most of OH∗ is observed at the vapor surface. This result implies that the steamer-type of aqua plasma was generated in the vapor bubble covered over a metal electrode tip, and the charged particles disperse along the surface of the vapor bubble.

Index Terms—Aqua plasma, electrolyte, hydroxyl radical, medical application, vapor bubble.

10.1109/TPS.2011.2159133