Electrical, Thermal and Optical Parametric Study of Guided Ionization Waves Produced with a Compact μs-Pulsed DBD-Based Reactor

Abstract

Atmospheric pressure guided ionization waves (GIWs) that are driven by ns/µs-pulsed high voltages, are promising tools in the biomedical field allowing for the effective production of reactive species and metastables without thermal damages of the specimens that are exposed. In most cases, plasma is produced in noble gases using dielectric barrier discharge (DBD) devices of more-or-less sophisticated geometries. In this study, a compact low-cost DBD reactor of very simple geometry is presented. It is fed with pure helium and driven by positive µs-pulsed high voltage (amplitude: 4.5-8 kV, pulse width: 1-10 µs) of audio frequencies (5-20 kHz), while it operates consistently for long time periods in a wide range of conditions. The produced plasma exhibits propagation lengths up to 4 cm and rich chemical reactivity is established outside the reactor, depending on the device's experimental parameters. Besides, the dielectric tube's temperature during plasma operation is an important factor, which is linked to the plasma characteristics. This temperature and its variations are thoroughly investigated herein, along with GIWs electrical features versus the electrical parameters of the pulsed power supply. Accordingly, it is demonstrated that not all of the operational windows are adequate for thermal-free operation and suitable operating conditions of this system are proposed for diverse applications, such as biomedical (low gas temperature is a prerequisite) and surface treatments of solid materials (low temperatures are not required).

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

“…Results for the case of a floating-potential plate were presented in [4,27]. The coefficient R 2 of the fitting is also shown in the lower image, attesting a rather good agreement between the experimental and the synthetic OH(A-X) spectra, in accordance with similar works [54,60,61]. Note that when the glass plate is grounded, the emission intensity of N2(SPS) is much higher than when using a floating-potential plate.…”

“…Since the O(3p 5 P) radiative emission intensity is negligible when using a floating-potential plate (figure 5), and the TGas and TPlate are close to TRoom (see [4] and figure 7), it can be fairly assumed that, in this case, Ar metastables are involved in the bibenzyl removal from the central spot observed at texp=60 s in figure 8. Note that N2 + (B) is not formed under our experimental conditions because Ar metastables do not have enough energy to ionize N2(X), as it is done by He metastables [61]. However, the formation of other nitrogen ions such as N4 + (and Ar ions such as Ar + and Ar2 + ) is possible [53,55].…”

Correlations between gaseous and liquid phase chemistries induced by cold atmospheric plasmas in a physiological buffer

“…Firstly, OES measurements were performed on the plasma phase. Qualitatively, the same species as in our previous works (different reactors [49][50][51] and power supplies 16 5). Thus, the intensity for a given specie can only be compared upon the different shielding gas conditions.…”

Reactive Oxygen Species Generated by Cold Atmospheric Plasmas in Aqueous Solution: Successful Electrochemical Monitoring in Situ under a High Voltage System

“…Cold atmospheric plasmas (CAPs), and specifically the so-called “guided ionization waves”, , are increasingly used systems in very different fields ranging from polymer science to surface treatment and etching and medical applications among others. They consist of a complex mixture of neutral atoms and molecules, electrons, charged particles (ions), excited atoms, and molecules.…”