Investigation of plasma dynamics and spatially varying O and OH concentrations in atmospheric pressure plasma jets impinging on glass, water and metal substrates

Abstract

Atmospheric pressure plasma jets (APPJs) have attracted considerable attention over the last decade, specifically for use in surface engineering. A comparative study of an APPJ, driven by pulsed DC voltage, is conducted in order to examine the plasma impingement onto different surfaces. In this paper, the effect of gas flow rate and composition is investigated using three kinds of substrates: dielectric glass, distilled water and metal plate using fast imaging. Alongside discharges associated with rising and falling voltage, a so-called third discharge is observed during the pulse for water and metal surfaces which corresponds to a restrike breakdown from surfaces to nozzle. The differences in plasma dynamics observed are mainly attributed to the differences in substrate conductivity. In addition, spatial and temporal distributions of OH and O density are investigated by means of laser induced fluorescence (LIF). The OH/O LIF intensity is found to be much higher for metal and water substrates compared to the glass plate. We attribute this effect to the differences in power dissipation associated with the presence and intensity of the third discharge. Effects of gas flow rate and seed gas (H 2 O and O 2 ) mixing on the LIF enhancement are also studied. The related results provide additional insights for optimizing the generation of reactive species.

Numerical Study of Jet–Target Interaction: Influence of Dielectric Permittivity on the Electric Field Experienced by the Target

“…The same macroscopic behaviors reported in Norberg et al [27] have been observed and their effect on the electron properties have been reported, with electron density close to the target reaching three times higher values with a metallic target than a glass target. Other experimental and numerical works [12,39,51] have found the same tendencies as in Norberg et al [27], in terms of influence of the target on discharge velocity, radial spreading on the target and electric field in the front of propagation.…”

“…The interaction of jets with dielectric surfaces of different permittivities has been addressed in several experimental and numerical works [2,5,10,12,15,20,26,27,33,39,45,50,51,53]. In Norberg et al [27] it has been studied numerically in 2D the impact of He jets on dielectric and metallic grounded targets with a −15 kV voltage pulse.…”

Experimental investigation of a ns-pulsed argon plasma jet for the fast desorption of weakly volatile organic compounds deposited on glass substrates at variable electric potential

“…Moreover, the speed of the ionization wave and the electron/ion densities increase in the presence of such targets as compared to dielectrics with low permittivity [11]. On the contrary, a greater spread of the ionization wave on the surface and a deeper penetration of the electric field was observed for dielectric substrates [10][11][12][13][14][15].…”

Investigation of mode interconversion for interfacial pattern formation through plasma–surface interaction

“…Until now, some efforts have been made to investigate the interactions between APPJ and substrates from different perspectives . Viegas et al reported the volume and surface charge influence on the electric field distribution with numerical and experimental methods.…”

“…Viegas et al reported the volume and surface charge influence on the electric field distribution with numerical and experimental methods. Yue et al investigated the plasma dynamics and spatially varying O and OH concentrations with different substrates. Darny et al studied the effect of a conductive target on plasma properties in He discharge and identified the mechanisms after ionization front impact on the target surface.…”