Effect of background ionization on plasma ignition dynamics

Qiu, Yue; Xian, Yuezhong; Lü, Xinpei; Ostrikov, Kostya Ken

doi:10.1063/1.4977805

Cited by 9 publications

(6 citation statements)

References 43 publications

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“…It is well known that the breakdown delay time is mainly influenced by the electric field and the initial charged particles in the discharge space [29,30]. In this work, the amplitude of the voltage pulse keeps constant under different flow rates.…”

Section: Discharge Delay-timementioning

confidence: 86%

Study on the characteristics of helium plasma jet by pulsed micro-hollow cathode discharge

Duan¹,

Li²,

He³

et al. 2021

Plasma Sources Sci. Technol.

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In this paper, the helium plasma jet generated by micro-hollow cathode discharge (MHCD) was studied. The MHCD was driven by a square-wave pulsed power source, and the characteristics of discharge and plasma jet were measured experimentally. The influences of the gas flow rate on the MHCD and the plasma jet were investigated. And the propagation mechanisms of the plasma jet were analyzed. The results show that within 100–1000 sccm of the gas flow rate, the breakdown delay time of the MHCD increases with the helium flow increasing. It is considered that the gas flow affects the density of seed electrons and thus the breakdown delay time. With the helium flow rate increasing, the whole plasma jet length increases firstly and then decreases. A detailed investigation shows that during one discharge pulse, two distinguishable propagation processes of the plasma jet are observed. It is found that the jet of the first stage is formed during the rising edge of the current pulse, while the other is generated after the discharge current becomes stable. The propagation velocity of jet in the first stage is on the order of several km s−1, which is similar to that of the discharge evolution obtained by simulation. And the propagation speed of the jet in the second stage is on the order of several hundred m s−1, which is close to the velocity of gas flow. The spatial–temporal distributions of light emission show that high-energy electrons can only be observed during the jet propagation in the first stage, and low-energy electrons can be detected in both the first and second stages. The results show that the electric field plays an important role on the jet propagation in the first stage, and the jet propagation during the second stage is mainly promoted by the thermal gas expansion.

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Section: Discharge Delay-timementioning

confidence: 86%

Study on the characteristics of helium plasma jet by pulsed micro-hollow cathode discharge

Duan¹,

Li²,

He³

et al. 2021

Plasma Sources Sci. Technol.

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“…The timesteps are non-adaptive and fixed at 2 × 10 −13 s. Similar to [58], a singular new electron super-particle is added to the simulation domain at random positions at each timestep in order to account for random events such as cosmic radiation, photo-ionization, various SEE processes, etc. as described in [59][60][61]. These random events are beyond the scope of the available VSim functions.…”

Section: Simulated Geometrymentioning

confidence: 99%

Computational study of simultaneous positive and negative streamer propagation in a twin surface dielectric barrier discharge via 2D PIC simulations

Zhang¹,

Nguyen-Smith²,

Beckfeld³

et al. 2021

Plasma Sources Sci. Technol.

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The propagation mechanisms of plasma streamers have been observed and investigated in a surface dielectric barrier discharge (SDBD) using 2D particle in cell simulations. The investigations are carried out under a simulated air mixture, 80% N 2 and 20% O 2 , at atmospheric pressure, 100 kPa, under both DC conditions and a pulsed DC waveform that represent AC conditions. The simulated geometry is a simplification of the symmetric and fully exposed SDBD resulting in the simultaneous ignition of both positive and negative streamers on either side of the Al 2 O 3 dielectric barrier. In order to determine the interactivity of the two streamers, the propagation behavior for the positive and negative streamers are investigated both independently and simultaneously under identical constant voltage conditions. An additional focus is implored under a fast sub nanosecond rise time square voltage pulse alternating between positive and negative voltage conditions, thus providing insight into the dynamics of the streamers under alternating polarity switches. It is shown that the simultaneous ignition of both streamers, as well as using the pulsed DC conditions, providing both an enhanced discharge and an increased surface coverage. It is also shown that additional streamer branching may occur in a cross section that is difficult to experimentally observe. The enhanced discharge and surface coverage may be beneficial to many applications such as, but are not limited to: air purification, volatile organic compound removal, and plasma enhanced catalysis.

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“…At E/N > 400 Td, dissociation reactions from the electron impact of N 2 molecules and various charge exchange processes predominate. Simplified approaches can also be useful in obtaining estimates of the production efficiency of chemically active species [40], or in revealing qualitative trends related to the ignition dynamics of periodic discharge events [41].…”

Section: Introductionmentioning

confidence: 99%

Non-equilibrium kinetics of the ground and excited states in N₂–O₂under nanosecond discharge conditions: extended scheme and comparison with available experimental observations

Šimek¹,

Bonaventura²

2018

J. Phys. D: Appl. Phys.

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A numerical 0D kinetic model is developed here to simulate the detailed kinetics of the ground and excited electronic states of atmospheric gases occurring under streamer discharge conditions. The model is based on an extended kinetic scheme that involves state-to-state vibrational kinetics of the ground electronic states of N2, O2 and NO diatomics, including e–V, V–V and V–T energy transfers, and contains about 104 processes for more than 500 tracked state-specific states (including the higher excited and autoionising states of NI/OI atomic species), and also for state-non-specific species. This scheme takes into account the most important radiative processes occurring in N2 and N2–O2 mixtures that are of diagnostic interest, including the extreme ultraviolet and vacuum ultraviolet radiation produced by many excited and autoionising states of NI/OI. The dependence of the rates of electron-impact processes on the reduced electric field E/N is found by solving the Boltzmann equation for electrons in the two-term approximation using the Boltzmann equation solver Open Source library, BOLOS. We examine several test cases: pure nitrogen at 50 and 200 Torr and synthetic air at 10, 50 and 760 Torr, at a gas temperature of 300 K. The numerical results for pure nitrogen were compared with experimental results recently obtained by laser induced fluorescence for metastables. Good qualitative agreement was observed between numerical simulations and experiments at vibronic levels v = 2–5, giving important feedback on the appropriateness of the kinetic scheme. Numerical results were also used to find several general spectrometric signatures that might be helpful in the development of diagnostic procedures.

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Effect of background ionization on plasma ignition dynamics

Cited by 9 publications

References 43 publications

Study on the characteristics of helium plasma jet by pulsed micro-hollow cathode discharge

Study on the characteristics of helium plasma jet by pulsed micro-hollow cathode discharge

Computational study of simultaneous positive and negative streamer propagation in a twin surface dielectric barrier discharge via 2D PIC simulations

Non-equilibrium kinetics of the ground and excited states in N₂–O₂under nanosecond discharge conditions: extended scheme and comparison with available experimental observations

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Effect of background ionization on plasma ignition dynamics

Cited by 9 publications

References 43 publications

Study on the characteristics of helium plasma jet by pulsed micro-hollow cathode discharge

Study on the characteristics of helium plasma jet by pulsed micro-hollow cathode discharge

Computational study of simultaneous positive and negative streamer propagation in a twin surface dielectric barrier discharge via 2D PIC simulations

Non-equilibrium kinetics of the ground and excited states in N2–O2under nanosecond discharge conditions: extended scheme and comparison with available experimental observations

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Non-equilibrium kinetics of the ground and excited states in N₂–O₂under nanosecond discharge conditions: extended scheme and comparison with available experimental observations