A novel large-scale plasma source: Two discharge modes and their correlation to the production of aqueous reactive species

In this paper, a novel large-scale plasma source is put forward, which can generate two modes of discharge, i.e. the surface dielectric barrier discharge and the plasma jet array, by just varying the helium gas flow rate. It is found that the discharge power changes a little with the increasing gas flow rate, but the densities of reactive species in the gas phase and in the treated water change a lot. In particular, the gaseous O₃ has its density decreasing while the aqueous O₃ has its concentration increasing with the increasing gas flow rate. In the plasma-treated water, the reactive nitrogen species such as nitrite and nitrate have their concentrations first increasing and then decreasing, while the reactive oxygen species such as H₂O₂, O₃ and OH have their concentrations increasing monotonically, implying that the plasma source is well-adaptive for different application requirements.