Plasma generation inside externally supplied Ar bubbles in water

Radio-frequency glow-like plasmas have been produced in Ar bubbles in water that flows in a quartz tube equipped with electrodes. Plasmas in bubbles, (or 'bubble plasmas' in short) may be used to induce some specific chemical reactions in liquids. It has been demonstrated that bubble plasmas can decompose methylene blue (MB) dissolved in water and hydroxyl (OH) radicals are present in the gas-phase plasmas. Therefore it may be presumed that decomposition of MB is caused either directly by OH radicals that are generated in the bubble plasmas and diffuse into the aqueous solution or indirectly by derivatives of such OH radicals formed in the solution.