Pre-breakdown phase of coplanar dielectric barrier discharge in helium

Morávek, Tomáš; Čech, Ján; Navrátil, Zdeněk; Ráheľ, Jozef

doi:10.1051/epjap/2016150538

Cited by 6 publications

(11 citation statements)

References 15 publications

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“…For the case of corona discharges, the similar contributions of Laan et al [70] or Petit et al [71] can be mentioned. We believe that the enhanced methodology of current measurements presented in this paper can contribute significantly to the recently-reported special cases of the discharging phenomena in extremely weak prebreakdown phases, whether at the dielectric surface [14,31,32] or in the volume [27,29,30].…”

Section: Discussionmentioning

confidence: 79%

“…Typically, in order to study the microdischarge current development the required resolution of the current probe has to go to sub-ns times and μA. Moreover, a low current discharging phenomenon was observed recently during the prebreakdown phases of surface and volume barrier discharges [14,27,[29][30][31][32], which is hard to study without the necessary dynamical range in the current probing system.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, optical emission, absorption and laser spectroscopy techniques have dominated as tools for detailed plasma investigation. Precise current measurements and their proper analysis are somewhat left behind, although the investigation of ultra-fast, low-current phenomena (as reported in [14,27,[29][30][31][32]) could significantly benefit from them. In this paper, we present a simple self-made current probe and compare its performance with some commercial current probes in common usage.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Advanced electrical current measurements of microdischarges: evidence of sub-critical pulses and ion currents in barrier discharge in air

Synek¹,

Zemánek²,

Kudrle³

et al. 2018

Plasma Sources Sci. Technol.

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Electrical current measurements in corona or barrier microdischarges are a challenge as they require both high temporal resolution and a large dynamic range of the current probe used. In this article, we apply a simple self-assembled current probe and compare it to commercial ones. An analysis in the time and frequency domain is carried out. Moreover, an improved methodology is presented, enabling both temporal resolution in sub-nanosecond times and current sensitivity in the order of tens of microamperes. Combining this methodology with a high-tech oscilloscope and self-developed software, a unique statistical analysis of currents in volume barrier discharge driven in atmospheric-pressure air is made for over 80 consecutive periods of a 15 kHz applied voltage. We reveal the presence of repetitive sub-critical current pulses and conclude that these can be identified with the discharging of surface charge microdomains. Moreover, extremely low, long-lasting microsecond currents were detected which are caused by ion flow, and are analysed in detail. The statistical behaviour presented gives deeper insight into the discharge physics of these usually undetectable current signals.

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Section: Discussionmentioning

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Advanced electrical current measurements of microdischarges: evidence of sub-critical pulses and ion currents in barrier discharge in air

Synek¹,

Zemánek²,

Kudrle³

et al. 2018

Plasma Sources Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…As indicated by Hudson and Loeb, and briefly discussed in section 2, the need for more correct terminology regarding the breakdown phenomena emerged more than a half century ago [14]: 'Some common misunderstandings can be avoided if a careful distinction is made between the terms breakdown and spark breakdown.' Unfortunately, in the recent literature not only the spark breakdown but many other not well defined terms as low and high pressure breakdowns [269], pre-Townsend [270] and Townsend breakdowns [271], streamer and leader downs [272], partial [273] and corona breakdowns [274], and streamer-like breakdowns [275] are used just within the relatively narrow topic of our review. Nevertheless, since in the technical literature the term 'electric breakdown' usually means the process of plasma production in an external electric field, [276], as already suggested in the Introduction, the simplest way to avoid of such complex and confusing terminology is to apply the term 'electric breakdown' as a synonym for all types self-sustained gas discharges, where the gaseous insulation breaks down and an electric current flows the gap.…”

Section: Conclusion and Summarymentioning

confidence: 99%

Streamer breakdown: cathode spot formation, Trichel pulses and cathode-sheath instabilities

Černák

Hoder

Bonaventura

2020

Plasma Sources Sci. Technol.

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The review provides an up-to-date overview and discussion of phenomena related to positive streamer breakdowns in short uniform and non-uniform field (corona) gaps. The terminology used to specify different types of streamer phenomena is critically discussed in light of a unified theory of high-pressure gas discharges describing the sequence of ionization events from initial electron avalanches up to a partial or complete breakdown. The emphasis is given to the understanding of the formation of an active cathode spot by the streamer arrival to the cathode, which is the critical but still obscure phase of the breakdown development. Based on the analysis including a computer simulation model a hypothesis is advanced that also such widely studied and practically important gas discharge phenomena as negative corona Trichel pulses and fast ionization instabilities in cathode regions of high-pressure gas discharges are due to the formation of positive streamers in the immediate cathode vicinity. The proposed hypothesis offers attractive feature of the unification of a wide scale of high-pressure gas discharges within the general class of positive streamer initiated breakdown phenomena. Moreover, it provides indications for further study in the field both by experiment and computer simulations.

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“…Experimental setups able to resolve the short timescale of the pre-breakdown phase are uncommon. In one case based on a different geometrical setup [65], the co-planar DBD in argon was observed by using high-speed camera imaging, which has limited resolution in time. This suggests that the numerical approach presented in this research might be used to resolve the details of the pre-breakdown state of a gaseous discharge, not presently detectable experimentally.…”

Section: Onset Phasementioning

confidence: 99%

Pre-breakdown to stable phase and origin of multiple current pulses in argon dielectric barrier discharge

Gautam¹,

Morra²

2021

Plasma Sci. Technol.

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We report on the results of numerical models of the (i) initial growth and (ii) steady state phases of atmospheric-pressure homogeneous dielectric barrier discharge in argon. We employ our new in-house code called PyDBD, which solves continuity equations for both particles and energy, shows exceptional stability, is accelerated by adaptive time stepping and is openly available to the scientific community. Modeling argon plasma is numerically challenging due to the lower speeds of more inertial ions compared to more commonly modeled neon and helium, but its common use for plasma jets in medicine makes its modeling compelling. PyDBD is here applied to modeling two setups: (i) the exponential growth from natural electron-ion seeds (onset phase) until saturation is reached and (ii) the multiple current pulses that naturally appear during the steady state phase. We find that the time required for the onset phase, when the plasma density grows from 109 m−3 to 1017 m−3, varies from 80 μs at 4.5 kV down to a few μs above 6.5 kV, for voltage frequency f = 80 kHz and gap width d g = 0.9 mm. At the steady state, our model reproduces two previously observed features of the current in dielectric barrier discharge reactors: (1) an oscillatory behavior associated to the capacitative character of the circuit and (2) several (N p) current pulses occurring every half sinusoidal cycle. We show that the oscillations are present during the exponential growth, while current pulses appear approaching the steady state. After each micro-discharge, the gas voltage decreases abruptly and charged particles rapidly accumulate at the dielectric boundaries, causing avalanches of charged particles near the reactor boundaries. Finally, we run a parametric study finding that N p increases linearly with voltage amplitude V amp, is inversely proportional to dielectric gap d g and decreases when voltage frequency f increases. The code developed for this publication is freely available at the address https://github.com/gabersyd/PyDBD.

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Pre-breakdown phase of coplanar dielectric barrier discharge in helium

Cited by 6 publications

References 15 publications

Advanced electrical current measurements of microdischarges: evidence of sub-critical pulses and ion currents in barrier discharge in air

Advanced electrical current measurements of microdischarges: evidence of sub-critical pulses and ion currents in barrier discharge in air

Streamer breakdown: cathode spot formation, Trichel pulses and cathode-sheath instabilities

Pre-breakdown to stable phase and origin of multiple current pulses in argon dielectric barrier discharge

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