Spatially and temporally resolved H and OH densities in a nanosecond pulsed plasma jet: an analysis of the radical generation, transport, recombination and memory effects

Yue, Yuanfu; Jiang, Jinhui; Kondeti, V. S. Santosh K.; Bruggeman, Peter

doi:10.1088/1361-6463/abce2a

Cited by 18 publications

(33 citation statements)

References 29 publications

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“…In fact, most features of DBD operation, from ignition to reproducibility, uniformity and jittering, rely on the general idea of memory effects. These can be present in the gas phase volume 16 – 18 or on the dielectric surfaces 19 . In the recent work by Fan et al 19 , a “wall voltage” in between repetitive discharges has been indirectly measured through a series of reference capacitors as a surface charging memory effect.…”

Section: Introductionmentioning

confidence: 99%

Quantification of surface charging memory effect in ionization wave dynamics

Viegas

Slikboer

Bonaventura

et al. 2022

Sci Rep

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The dynamics of ionization waves (IWs) in atmospheric pressure discharges is fundamentally determined by the electric polarity (positive or negative) at which they are generated and by the presence of memory effects, i.e. leftover charges and reactive species that influence subsequent IWs. This work examines and compares positive and negative IWs in pulsed plasma jets (1 $$\upmu $$ μ s on-time), showing the difference in their nature and the different resulting interaction with a dielectric BSO target. For the first time, it is shown that a surface charging memory effect is produced, i.e. that a significant amount of surface charges and electric field remain in the target in between discharge pulses (200 $$\upmu $$ μ s off-time). This memory effect directly impacts IW dynamics and is especially important when using negative electric polarity. The results suggest that the remainder of surface charges is due to the lack of charged particles in the plasma near the target, which avoids a full neutralization of the target. This demonstration and the quantification of the memory effect are possible for the first time by using an unique approach, assessing the electric field inside a dielectric material through the combination of an advanced experimental technique called Mueller polarimetry and state-of-the-art numerical simulations.

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Section: Introductionmentioning

confidence: 99%

Quantification of surface charging memory effect in ionization wave dynamics

Viegas

Slikboer

Bonaventura

et al. 2022

Sci Rep

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“…Figure8(b) shows the variation in the H • densities as a function of axial position in He/H 2 O and He/Ar/H 2 O plasmas at a total gas flow rate of 1.0 slm. The H • densities in both He/H 2 O and He/Ar/H 2 O plasmas reach the steady-state density of ∼ 3 × 10 21 m −3 within ∼2 mm, followed by a fast decay in the effluent because of the short lifetime of H • in the presence of • OH radical, which is a highly effective quencher of H • via three-body recombination reaction[82]. The H • density in He/H 2 O and He/Ar/H 2 O plasmas is almost an order of magnitude higher than the corresponding• OH density.…”

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confidence: 99%

Plasma-droplet interaction study to assess transport limitations and the role of ^⋅OH, O^⋅,H^⋅,O₂(a ¹Δ_g),O₃, He(2³ S) and Ar(1s ₅) in formate decomposition

Nayak

Oinuma

Yue

et al. 2021

Plasma Sources Sci. Technol.

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Plasmas interacting with liquid microdroplets are gaining momentum due to their ability to significantly enhance the reactivity transfer from the gas phase plasma to the liquid. This is, for example, critically important for efficiently decomposing organic pollutants in water. In this contribution, the role of ⋅OH as well as non-⋅OH-driven chemistry initiated by the activation of small water microdroplets in a controlled environment by diffuse RF glow discharge in He with different gas admixtures (Ar, O2 and humidified He) at atmospheric pressure is quantified. The effect of short-lived radicals such as O⋅ and H⋅ atoms, singlet delta oxygen (O2(a 1Δg)), O3 and metastable atoms of He and Ar, besides ⋅OH radicals, on the decomposition of formate dissolved in droplets was analyzed using detailed plasma diagnostics, droplet characterization and ex situ chemical analysis of the treated droplets. The formate decomposition increased with increasing droplet residence time in the plasma, with ∼70% decomposition occurring within ∼15 ms of the plasma treatment time. The formate oxidation in the droplets is shown to be limited by the gas phase ⋅OH flux at lower H2O concentrations with a significant enhancement in the formate decomposition at the lowest water concentration, attributed to e−/ion-induced reactions. However, the oxidation is diffusion limited in the liquid phase at higher gaseous ⋅OH concentrations. The formate decomposition in He/O2 plasma was similar, although with an order of magnitude higher O⋅ radical density than the ⋅OH density in the corresponding He/H2O plasma. Using a one-dimensional reaction–diffusion model, we showed that O2(a 1Δg) and O3 did not play a significant role and the decomposition was due to O⋅, and possibly ⋅OH generated in the vapor containing droplet-plasma boundary layer.

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“…Yue et al [21] studied the plasma dynamics and instabilities in a pulsed pin-to-liquid discharge and measured the water vapor density in the adjacent region to the liquid surface. Meanwhile, several researchers applied a plasma jet to the solution and in situ diagnosed and analyzed various important active particles including OH, H, O, H 2 O 2 , and so on above the treated solution surface [34][35][36] . Pai [25] studied the penetration depth of key reactive species in the interfacial layer by Raman light-sheet microspectroscopy.…”

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confidence: 99%

Plasma‐enhanced evaporation and its impact on plasma properties and gaseous chemistry in a pin‐to‐water pulsed discharge

Yang

Qiao

et al. 2023

Plasma Processes & Polymers

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The plasma in contact with liquids has led to various novel applications such as plasma biomedicine, material synthesis, and so on. However, the phenomenon of evaporation under plasma treatment and its impact on plasma–liquid interactions has a limited understanding. In this study, the spatially and temporally resolved behavior of water vapor production and its induced influences on plasma properties and gaseous chemistry were studied in detail in an atmospheric pressure pin‐to‐water pulsed He discharge. Diagnostic methods such as laser‐induced fluorescence (LIF) and high‐resolution optical emission spectroscopy (OES) were applied to determine the water vapor and OH radical densities, as well as key plasma parameters such as the gas temperature and electron density. It shows that the physicochemical properties of plasma vary among different discharge regions due to evaporation behavior stimulated during the pulsed discharge‐on phase. In addition, using simulation based on the experimental data, the mechanisms of how water vapor affects the observed spatiotemporal behaviors of OH radicals in different discharge regions are understood. Compared to the pin‐anode and liquid‐cathode sheath regions, proper electron parameters such as density and temperature, as well as water vapor density in the plasma‐positive column, significantly enhance the production of reactive OH radical through the dominant path of electron‐stimulated H2O dissociation. However, higher levels of electron parameters in the intense discharge region near the positive‐pin boundary enhance OH dissociation and finally result in the hollow distribution of OH density. From the global kinetic plasma simulation, the production of reactive hydroxide species playing key roles in plasma medicine treatments, such as O, H, HO2, H2O2, and hydrated ions including H+(H2O)4 and H+(H2O)5, are promoted noticeably as a result of the enhanced water evaporation process.

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Spatially and temporally resolved H and OH densities in a nanosecond pulsed plasma jet: an analysis of the radical generation, transport, recombination and memory effects

Cited by 18 publications

References 29 publications

Quantification of surface charging memory effect in ionization wave dynamics

Quantification of surface charging memory effect in ionization wave dynamics

Plasma-droplet interaction study to assess transport limitations and the role of ^⋅OH, O^⋅,H^⋅,O₂(a ¹Δ_g),O₃, He(2³ S) and Ar(1s ₅) in formate decomposition

Plasma‐enhanced evaporation and its impact on plasma properties and gaseous chemistry in a pin‐to‐water pulsed discharge

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Spatially and temporally resolved H and OH densities in a nanosecond pulsed plasma jet: an analysis of the radical generation, transport, recombination and memory effects

Cited by 18 publications

References 29 publications

Quantification of surface charging memory effect in ionization wave dynamics

Quantification of surface charging memory effect in ionization wave dynamics

Plasma-droplet interaction study to assess transport limitations and the role of ⋅OH, O⋅,H⋅,O2(a 1Δg),O3, He(23 S) and Ar(1s 5) in formate decomposition

Plasma‐enhanced evaporation and its impact on plasma properties and gaseous chemistry in a pin‐to‐water pulsed discharge

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Plasma-droplet interaction study to assess transport limitations and the role of ^⋅OH, O^⋅,H^⋅,O₂(a ¹Δ_g),O₃, He(2³ S) and Ar(1s ₅) in formate decomposition