The focus of this paper is on the spatially and temporally resolved measurements electric field in atmospheric-pressure plasma jets operating helium. Using Stark polarization spectroscopy method, temporal development was observed steps which were range 20–500 ns. Such resolution complemented by spatial 0.025 mm. Depending jet configuration, maximal strength bullet/streamer head between 10 20 kV cm−1. Electric are accompanied electrical spectroscopic diagnostics discharge evolution. It found...

The article describes the complex study of interaction a helium plasma jet with distilled water and saline. discharge development, spatial distribution excited species, electric field measurement results Schlieren imaging are presented. experiments showed that plasma–liquid could be prolonged proper choice gas composition between nozzle target. This depends on flow target distance. Increased conductivity liquid does not affect properties significantly. An increase enables an extension...

Atmospheric-pressure helium plasma jet operating in the bullet/streamer mode has been studied using optical emission spectroscopy. Electric field strength distribution is measured Stark polarization spectroscopy of He I 492.19 nm line. It shown that electric almost constant along axis. Measured agreement with theoretical predictions streamer propagation jets at atmospheric pressure. Obtained radial axial shows ring-shaped structure light a consequence such distribution.

Plasma catalysis, biomedical applications or atomic layer deposition at atmospheric pressure all make use of non-thermal plasmas in contact with a wide variety surfaces. As the presence target (substrate) has been shown to modify plasma addition modifying target, it is reasonable describe and study plasma-surface as one system. This work shows how dielectric metallic targets influences kHz AC-driven discharge He jet. Next bringing absolute values axial electric field along plume jet, surface...

Abstract The study of plasma–liquid interactions has evolved as a new interdisciplinary research field driven by the development plasma applications for water purification, biomedicine and agriculture. Electrical discharges in contact with liquids are rich source reactive species gas liquid phase which can be used to break polluting compounds or induce healing processes medical applications. An understanding fundamental plasma, interaction liquid, enables optimization chemistry large-scale...

Non-thermal plasma is a promising tool for novel technologies to treat water contaminated by recalcitrant pollutants. We report here on products, reactive species and mechanisms of the efficient degradation perfluorooctanoic acid (PFOA) achieved with self-pulsing discharge developed previously in our lab. Air or argon were used as feed gas, ultrapure tap aqueous medium. Identified organic intermediate products arise from chain-shortening defluorination reactions, latter achieving not only...

This report focuses on the dependence of electric field strength in effluent a vertically downwards-operated plasma jet freely expanding into room air as function gas flow speed. A 30 kHz AC-driven He was used coaxial geometry, with an amplitude 2 kV and between 700 sccm 2000 SCCM. The measured by means Stark polarization spectroscopy line at 492.19 nm. While minimum maximum fields remained unchanged, effect speed is to cause stretching profile space—the higher flow, longer less steep...

Gas discharge physics is particularly helpful to study many spectacular aspects of atmospheric electricity, e.g., lightning and sprite streamers. However, the observations double-headed streamers (DHS) in nature---formed after breakdown---remain an open question. Considering that topic DHS has been studied exclusively through theoretical numerical models, this Letter presents very first experimental model DHS. Here, a primary plasma jet device operated at ground pressure used ignite...

ABSTRACT Generation of the high electron density, atmospheric pressure, pulsed discharge over liquid surface is described. The densities around 10 18 cm −3 are achieved with only 40 mJ per pulse. operates in self‐triggering regime and working frequency can be adjusted by current power supply. It a spark‐like contact argon as gas. distinct nature its self‐organized propagation surface, which makes it suitable for treatment surfactants, such perfluoroalkyl substances triton. may also used good...

The results of the electric field measurements in capillary helium plasma jet are presented this article. Distributions for streamers determined different gas flow rates. It is found that strength front ionization wave decreases as it approaches to exit tube. values obtained under experimental conditions range 5–11 kV/cm. was increase above 1500 SCCM could induce substantial changes discharge operation. This reflected through formation brighter region and appearance maxima. Furthermore,...

In this paper a new method is proposed and tested for electric field measurements in the cathode region of low-temperature atmospheric pressure discharge helium. The uses intensity ratio two helium singlet lines: He I 21P–31D at 667.8 nm 21P–31S 728.1 nm. correlation between line was firstly obtained via Stark polarization spectroscopy 21P–41D 492.19 its forbidden counterpart dielectric barrier (DBD) Collisional–radiative model involved atomic levels utilized to confirm obtain functional...

Atmospheric-pressure helium plasma jet has been studied by optical emission spectroscopy and electrical measurements. Streamer/bullet properties of the are observed in positive voltage half cycle, whereas negative jet, they operate more as a glowlike atmospheric-pressure discharge. This is revealed spatially resolved measurements intensity distribution typical excited species electric field based on Stark polarization spectroscopy. Obtained radial axial bullet shows that ring-shaped...

Abstract The status of the research into and application non‐thermal plasmas for pollutant degradation in gases is discussed, including some fundamental topics engineering issues. Two reactor concepts, both based on dielectric barrier discharges (DBDs), are presented investigated various tasks. DBD‐stack shows a very good scalability was oxidation NO combustion (shipping diesel engine exhausts). processes were significantly enhanced by admixture hydrocarbons. Significant conversion at low...

A model of the isolated streamer head based on Meek's criterion avalanche to transition is applied for description plasma bullet propagation in a helium/air admixture. According previously proposed by Kulikovsky streamers air, along with knowledge one three parameters: electric field, ionization integral or width space charge layer, other two parameters could be determined. Furthermore, using current radius, it possible determine field-streamer velocity functional dependence. Obtained...

The article reports and discusses the results of a thorough spectroscopic investigation self-pulsing electrical discharge in contact with aqueous media. occurs between bare high voltage electrode positioned over liquid grounded ring submerged by liquid. It is supplied DC voltage, but it operates pulse mode that determined charging discharging parallelly connected capacitor. This type has attracted our attention due to its complex physics, as well efficiency inducing degradation highly inert...

A short overview of the emission spectroscopy methods for measuring macroscopic electric field in high pressure discharges with helium is given. The occurrence a consequence space charge buildup. It common feature discharge sheaths, streamer heads and double layers. spectroscopic are based on polarization-dependent Stark splitting shifting atomic lines presence relatively strong field. For their forbidden counterparts used. advantage ab initio basis which makes them independent other plasma...

The neutral gas temperature (Tg) of a single micro-hollow cathode discharge (MHCD) elaborated on silicon wafer is investigated. MHCD continuously powered in DC yielding plasma He, Ar and N2 gases close to atmospheric pressure. Values Tg are determined by means optical emission spectroscopy inside the vicinity cavity diameter. In this work, use resonant broadening infer thoroughly reconsidered taking into account reevaluation an empirical coefficient as well including weaker contribution Van...