Experimental study of streamers in pure N2and N2/O2mixtures and a ≈13 cm gap

Yi, Won Ju; Williams, P. F.

doi:10.1088/0022-3727/35/3/308

Cited by 137 publications

(119 citation statements)

References 29 publications

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“…The propagation velocity of the ionization front is in the range of 3 × 10 7 to 4 × 10 7 cm/s. We find that the calculated values for the frontal velocities agree well with the experimental results [21][22][23] and with those reported in [20,[24][25][26][27]. Measurements [21,22] of the average propagation velocity of the ionization front extend from 2 × 10 7 to 5 × 10 7 cm/s, the propagation average velocity [24,25] of the ionization wave is approximately of 5 × 10 7 cm/s, which agrees with our results.…”

Section: Resultssupporting

confidence: 91%

Monte Carlo simulation of corona discharge in SF6

Settaouti

2010

Electric Power Systems Research

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Section: Resultssupporting

confidence: 91%

Monte Carlo simulation of corona discharge in SF6

Settaouti

2010

Electric Power Systems Research

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“…During the 8-8.1 ns time, the streamer travels 0.1 mm, and the average velocity is nearly 10 6 m/s. This result is consistent with the reported experimental results by Yi and Williams [67]. They observed the streamer propagation of the needle-to-plane geometry produced in a short gap (0.5-1 cm) using high-speed photography.…”

Section: Electric Field Distribution and Streamer Propagation Velocitysupporting

confidence: 93%

“…The experimental results showed the steamer reached the cathode in 7 ns, and the average velocity was around 7.14 × 10 5 m/s. According to the experimental results in [67], the values of the speed deduced from various empirical formulas differed by almost one order of magnitude, even under the same experimental condition. In addition, experimental conditions (including gas, gap lengths, and electric field strengths) significantly affect the streamer propagation.…”

Section: Electric Field Distribution and Streamer Propagation Velocitymentioning

confidence: 95%

Numerical Modelling of Mutual Effect among Nearby Needles in a Multi-Needle Configuration of an Atmospheric Air Dielectric Barrier Discharge

et al. 2012

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Abstract:A numerical study has been conducted to understand the mutual effect among nearby needles in a multi-needle electrode dielectric barrier discharge. In the present paper, a fluid-hydrodynamic model is adopted. In this model, the mutual effect among nearby needles in a multi-needle configuration of an atmospheric air dielectric barrier discharge are investigated using a fluid-hydrodynamic model including the continuity equations for electrons and positive and negative ions coupled with Poisson's equation. The electric fields at the streamer head of the middle needle (MN) and the side needles (SNs) in a three-needle model decreased under the influence of the mutual effects of nearby needles compared with that in the single-needle model. In addition, from the same comparison, the average propagation velocities of the streamers from MN and SNs, the electron average energy profile of MN and SNs (including those in the streamer channel, at the streamer head, and in the unbridged gap), and the electron densities at the streamer head of the MN and SNs also decreased. The results obtained in the current paper agreed well with the experimental and simulation results in the literature.

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“…Streamers appear in early stages of atmospheric discharges such as sparks or sprite discharges [1,2]; they also play a prominent role in numerous technical processes. It is commonly observed that streamers branch spontaneously [3,4]. But how this branching is precisely determined by the underlying discharge physics is essentially not known.…”

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confidence: 99%

Streamer branching rationalized by conformal mapping techniques

2004

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Spontaneous branching of discharge channels is frequently observed, but not well understood. We recently proposed a new branching mechanism based on simulations of a simple continuous discharge model in high fields. We here present analytical results for such streamers in the Lozansky-Firsov limit where they can be modeled as moving equipotential ionization fronts. This model can be analyzed by conformal mapping techniques which allow the reduction of the dynamical problem to finite sets of nonlinear ordinary differential equations. Our solutions illustrate that branching is generic for the intricate head dynamics of streamers in the Lozansky-Firsov limit. When nonionized matter is suddenly exposed to strong fields, ionized regions can grow in the form of streamers. These are ionized and electrically screened channels with rapidly propagating tips. The tip region is a very active impact ionization region due to the self-generated local field enhancement. Streamers appear in early stages of atmospheric discharges such as sparks or sprite discharges [1,2]; they also play a prominent role in numerous technical processes. It is commonly observed that streamers branch spontaneously [3,4]. But how this branching is precisely determined by the underlying discharge physics is essentially not known. In recent work [5,6], we have suggested a branching mechanism from first principles. This work drew some attention [7,8], since the proposed mechanism yields quantitative predictions for specific parameters, and since it is qualitatively different from the older branching concept of the "dielectric breakdown model" [9][10][11]. This older concept actually can be traced back to concepts of rare long-ranged (and hence stochastic) photoionization events probably first suggested in 1939 by Raether [12]. Therefore, it came as a surprise that we predicted streamer branching in a fully deterministic model. Since our evidence for the phenomenon was mainly from numerical solutions together with a physical interpretation, the accuracy of our numerical scheme was challenged [13,14]. Furthermore, some authors have argued previously [15,16] that in a deterministic discharge model such as ours, an initially convex streamer head never could become locally concave, and that hence the consecutive branching of the discharge channel would be unphysical.Therefore in the present paper, we investigate the issue by analytical means. We show that the convex-to-concave evolution of the streamer head with successive branching is generic for streamers in the Lozansky-Firsov limit [5,6,17]. We define the Lozansky-Firsov limit as the stage of evolution where the streamer head is almost equipotential and surrounded by a thin electrostatic screening layer. While in the original paper [17], only simple steady state solutions with parabolic head shape are discussed, we will show here that a streamer in the Lozansky-Firsov limit actually can exhibit a very rich head dynamics that includes spontaneous branching. Furthermore, our analytical solutions disprove t...

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Experimental study of streamers in pure N₂and N₂/O₂mixtures and a ≈13 cm gap

Cited by 137 publications

References 29 publications

Monte Carlo simulation of corona discharge in SF6

Monte Carlo simulation of corona discharge in SF6

Numerical Modelling of Mutual Effect among Nearby Needles in a Multi-Needle Configuration of an Atmospheric Air Dielectric Barrier Discharge

Streamer branching rationalized by conformal mapping techniques

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