Overview of Experimental Studies of Plasma in Liquid Water at the University of Michigan and Progress towards a Practical Plasma Water Reactor

The interaction of plasmas with liquid water involves the complex interplay between both physical and chemical processes mediated by charged particles, fields and photons. These processes manifest themselves at the plasma liquid interface. Production and transport processes here remain still poor understood. Here, we review fundamental studies aimed at elucidating radical production and transport processes from the interface into the bulk solution. Radical transport is tracked using chemical probes The importance of plasma-driven circulation is discussed along side experimental data including schlieren and PIV measurements. Transport processes are particularly important for any practical plasma-based water reactor for purification. Here the primary technical challenge has been scale-up. Optimizing radical transport and maximizing plasma-liquid contact time is key to the realization of a practical device. Here we present two approaches to plasma-based water treatment using model organic contaminants to access performance. Prospects for future development are also discussed.