Plasma synthetic jet actuators for biological indirect treatment: the role of the charged particles

Plasma Synthetic Jet Actuators (PSJA) have demonstrated their ability to produce a flow from the surface where the Dielectric Barrier Discharge (DBD) is ignited. This ionic wind is due to the Electro Hydro Dynamic (EHD) interaction. These fluid-dynamic actuators enhance the delivery of reactive species towards the target to be treated. The long-life charged particles are generated within the plasma region and then carried on by the induced flow. The disinfection efficacy of PSJA used to indirectly treat different pathogens was demonstrated. In particular, the inactivation effect of free charges advected by the ionic wind has been investigated. An assessment of the various factors that may affect the production and the effect of the free charges are analysed. It was observed that humidity rate weakly influences the charge deposition. Besides, the most notable effect is an increase of the deposition time for higher humidity rate. In addition, a higher applied electric field produces higher charge deposition rates. Moreover, different geometries and dielectric materials have been considered. Linear actuators have proven to be more effective in charge delivery with respect to annular actuators. The EHD interaction was measured also for a streamer corona discharge utilised for cancer cells treatment.