Influence of field emission on microwave microdischarges

Levko, Dmitry; Raja, Laxminarayan L.

doi:10.1049/hve.2016.0010

Cited by 9 publications

(6 citation statements)

References 14 publications

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“…In air, the (pd) min predicted by Paschen's law is about 0.76 Torr cm [21]. The extremum of the gap distance d at atmospheric pressure is about ∼10 μm and the minimum breakdown voltage is V br,min ∼317 V. In the present needleto-plate configuration, the V br -d curve should be similar to that of the Paschen curve when d<10 μm.…”

Section: Discussionmentioning

confidence: 60%

“…In fact, it is in Boyle and Kisliuk's paper [12] that the first 'schematic' of the modified Paschen curve was highlighted. Thereafter, a number of experiments have shown that a plateau appears on the V br -pd curve when the gap is less than 10 μm, followed by a continuous decrease in V br when d is further decreased [13][14][15][16][17][18][19][20][21][22][23]. In 1999 Torres and collaborators [24,25] presented evidence for the failure of Paschen's law, especially for the decrease in the breakdown voltage at decreasing gap.…”

Section: Introductionmentioning

confidence: 99%

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Discharge characteristics of a needle-to-plate electrode at a micro-scale gap

Wang¹,

Ji²,

Zhang³

2018

Plasma Sci. Technol.

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To understand the discharge characteristics under a gap of micrometers, the breakdown voltage and current-voltage curve are measured experimentally in a needle-to-plate electrode at a microscale gap of 3-50 μm in air. The effect of the needle radius and the gas pressure on the discharge characteristics are tested. The results show that when the gap is larger than 10 μm, the relation between the breakdown voltage and the gap looks like the Paschen curve; while below 10 μm, the breakdown voltage is nearly constant in the range of the tested gap. However, at the same gap distance, the breakdown voltage is still affected by the pressure and shows a trend similar to Paschen's law. The current-voltage characteristic in all the gaps is similar and follows the trend of a typical Townsend-to-glow discharge. A simple model is used to explain the non-normality of breakdown in the micro-gaps. The Townsend mechanism is suggested to control the breakdown process in this configuration before the gap reduces much smaller in air.

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Section: Discussionmentioning

confidence: 60%

Section: Introductionmentioning

confidence: 99%

Discharge characteristics of a needle-to-plate electrode at a micro-scale gap

Wang¹,

Ji²,

Zhang³

2018

Plasma Sci. Technol.

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“…However, in discharge voltage between 19 and 20 kV, the H 2 O 2 concentration increased rapidly with the discharge voltage rise, accompanied by the phenomenon of a much brighter plasma area and a rapid growth of discharge current, as shown in figure 5. The rapid growth indicated that postbreakdown of the gas gap happened in this interval with electronic avalanche [20]. Within this interval, many more hybrid discharges occurred at the interface of water droplets and oxygen, due to the rapidly increased discharge power, leading to an increased H 2 O 2 concentration.…”

Section: The Influence Of Applied Voltagementioning

confidence: 97%

Influence of electrical parameters on H₂O₂generation in DBD non-thermal reactor with water mist

Xu¹,

Xiao²,

Hao³

et al. 2017

Plasma Sci. Technol.

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A dielectric barrier discharge (DBD) reactor is introduced to generate H 2 O 2 by non-thermal plasma with a mixture of oxygen and water mist produced by an ultrasonic atomizer. The results of our experiment show that the energy yield and concentration of the generated H 2 O 2 in the pulsed discharge are much higher than that in AC discharge, due to its high energy efficiency and low heating effect. Micron-sized liquid droplets produced by an ultrasonic atomizer in water mist have large specific surface area, which greatly reduces mass transfer resistance between hydroxyl radicals and water liquids, leading to higher energy yield and H 2 O 2 concentration than in our previous research. The influence of applied voltage, discharge frequency, and environmental temperature on the generated H 2 O 2 is discussed in detail from the viewpoint of the DBD mechanism. The H 2 O 2 concentration of 30 mg l −1 , with the energy yield of 2 g kW −1 h −1 is obtained by pulsed discharge in our research.

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“…Numerically and focusing on microwave microplasmas, most of the work performed has been focused either in one dimensional (1D) particle in cell (PIC) Monte Carlo models [26,33,34] or self-consistent 1D-two-dimensional (2D) fluid models in the quasi-static approximation [35,36]. Both 1D PIC and fluid simulations have provided important insight of breakdown voltages, frequency and field emission effects as well as spatial and temporal plasma evolution.…”

Section: Introductionmentioning

confidence: 99%

Full-wave and plasma simulations of microstrip excited, high-frequency, atmospheric pressure argon microdischarges

Kourtzanidis

2023

Plasma Sources Sci. Technol.

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Two-dimensional fully coupled EM wave-plasma simulations are used to study the formation, early transient and quasi-steady state of the argon plasma excited by a two-dimensional discontinuous microstrip line. The electromagnetic waves that normally propagate in the microstrip transmission line, radiate and scatter at the position of the gap and the electric field is enhanced primarily at the corner of the gap. The microdischarge is preferentially formed at this position of the EM field hotspot and in low frequencies propagates on the dielectric surface, much like a microwave surface streamer. In longer times, diffusion dominates and the whole gap is filled with plasma of maximum density in the order of $10^{20}$ $m^{-3}$ while it occupies a volume larger than the gap. Mean electron temperatures range from 2.8 to 3.9 eV, while the plasma reaches a quasi-static regime in approximately 2 $\mu$ s having reconfigured the transmission and radiation patterns of the slitted microstrip line. The tunability of the microstrip due to plasma formation provides means for sustaining the discharge in a stable regime. For the same input EM power, the electron temperature increases with increasing excitation frequency while electron densities found to decrease. For the same wave frequency, a decrease of the electron densities with increasing gap is also found in addition to a restriction of the discharge expansion. Finally, thicker dielectrics result to higher electron densities and electron temperatures as well as absorbed power from the plasma. These findings are attributed to the dependence of absorbed EM power and skin depth on the EM wave angular frequency, the critical for shielding electron density as well as the restructuring of the S-parameters due to the changes in operational parameters.

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Influence of field emission on microwave microdischarges

Cited by 9 publications

References 14 publications

Discharge characteristics of a needle-to-plate electrode at a micro-scale gap

Discharge characteristics of a needle-to-plate electrode at a micro-scale gap

Influence of electrical parameters on H₂O₂generation in DBD non-thermal reactor with water mist

Full-wave and plasma simulations of microstrip excited, high-frequency, atmospheric pressure argon microdischarges

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Influence of field emission on microwave microdischarges

Cited by 9 publications

References 14 publications

Discharge characteristics of a needle-to-plate electrode at a micro-scale gap

Discharge characteristics of a needle-to-plate electrode at a micro-scale gap

Influence of electrical parameters on H2O2generation in DBD non-thermal reactor with water mist

Full-wave and plasma simulations of microstrip excited, high-frequency, atmospheric pressure argon microdischarges

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Influence of electrical parameters on H₂O₂generation in DBD non-thermal reactor with water mist