Striated microdischarges in an asymmetric barrier discharge in argon at atmospheric pressure

Hoder, Tomáš; Loffhagen, Detlef; Wilke, Charles R.; Grosch, Helge; Schäfer, Jan; Weltmann, Klaus‐Dieter; Brandenburg, Ronny

doi:10.1103/physreve.84.046404

Cited by 28 publications

(38 citation statements)

References 50 publications

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“…In this case, there are no volume and surface charges present in the gap or at the dielectric when the voltage is applied. In contrast to test case 1, a 2D model is required to describe the transient discharge dynamics and the formation of the constricted discharge channel occurring in the considered geometry at atmospheric pressure [30]. Due to the high computational costs, the discharge is considered to be axisymmetric for simplification and the model equations are solved in cylindrical coordinates.…”

Section: B Test Casesmentioning

confidence: 99%

Automated Fluid Model Generation and Numerical Analysis of Dielectric Barrier Discharges Using Comsol

Jovanović

Stankov

Loffhagen

et al. 2021

IEEE Trans. Plasma Sci.

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Section: B Test Casesmentioning

confidence: 99%

Automated Fluid Model Generation and Numerical Analysis of Dielectric Barrier Discharges Using Comsol

Jovanović

Stankov

Loffhagen

et al. 2021

IEEE Trans. Plasma Sci.

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“…Conditions for instability in a fluid model that indicated the importance of negative ions were developed 20 and reviewed. 14,15 However, more recent studies 16,[22][23][24] and experiments [25][26][27][28][29][30][31][32] indicate that if kinetic effects are included, negative ions are not required to observe striations.…”

Section: Introductionmentioning

confidence: 99%

Ionization instability induced striations in low frequency and pulsed He/H2O atmospheric pressure plasmas

2018

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In previous work [Kawamura et al., Plasma Sources Sci. Technol. 25, 054009 (2016)] and [Kawamura et al., J. Phys. D: Appl. Phys. 50, 145204 (2017)], 1D kinetic particle-in-cell (PIC) simulations of narrow gap (1 to 4 mm), high frequency (27 MHz) or dc-driven, He/2%H 2 O atmospheric pressure plasmas (APPs) showed an ionization instability resulting in standing striations (spatial oscillations) in the bulk plasma. We developed a steady-state striation theory which showed that the striations are due to non-local electron kinetics. In both the high frequency and dc-driven cases, the equilibrium electron density n 0 in the plasma bulk was stationary. In this work, we first conduct 1D PIC simulations of a 1 mm gap He/2%H 2 O APP, driven by a sinusoidal current at a low frequency of f ¼ 50 kHz such that x ¼ 2pf is well below the ionization frequency iz. In this case, n 0 varies with time, and we observe a time-varying instability which quasistatically depends on n 0 (t). At each phase of the rf cycle, the discharge resembles a dc discharge at the same n 0. At higher frequencies (200 kHz-1 MHz), x approaches iz , and quasistatic equilibrium at each phase breaks down. The discharge is also driven with a 200 kHz, 50% duty cycle square wave pulse with a short rise and fall time of 0.1 ls in an attempt to directly measure the striation growth rate s during the on-cycle before it saturated. However, the spike in current during the rise time leads to a spike in electron temperature T e and hence iz and s at the beginning of the rise which saturated during the beginning of the on-cycle. To predict the instability growth rate and saturation during and after the current spike, we extend our striation theory to include time-varying n 0 , T e , iz , as well as terms for the nonlinear saturation and noise floor of the striation amplitude. The timevarying global model predictions are compared to the PIC simulations, showing reasonable agreement.

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“…They are known for decades because they appear also in low-pressure dc glow discharges. The observation of striations has been described for various types of atmospheric discharges, for example, in DBDs [2] or in MW microdischarges [3], but not yet for an RF jet. Herein, Manuscript we observed striations of a particular filament that appears during the transition of the two-filament mode (II) into the one-filament mode (I) in the RF argon plasma jet [II→Y→I, see Fig.…”

mentioning

confidence: 99%

High-Speed Visualization of Filament Instabilities and Self-Organization Effect in RF Argon Plasma Jet at Atmospheric Pressure

Schäfer

Šperka

Gött

et al. 2014

IEEE Trans. Plasma Sci.

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An RF argon plasma jet has been explored using high-speed camera imaging at 10 000 frames/s. Small variations of gas flow and/or RF power lead to instabilities of the filament movement. Two types of instabilities have been observed depending on the interrelated azimuthal velocities of filaments. In the case of antiparallel filament velocities, one filament is collapsing and fuses with the other filament, while the collapsing filament exhibits a striated structure. In the case of parallel velocities, both filaments establish a symmetric configuration and rotate with constant velocity in the jet. Spatially and temporally resolved features are visualized with a time-colored stroboscopic image.Index Terms-Image processing, plasma materials processing, plasma stability.

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Striated microdischarges in an asymmetric barrier discharge in argon at atmospheric pressure

Cited by 28 publications

References 50 publications

Automated Fluid Model Generation and Numerical Analysis of Dielectric Barrier Discharges Using Comsol

Automated Fluid Model Generation and Numerical Analysis of Dielectric Barrier Discharges Using Comsol

Ionization instability induced striations in low frequency and pulsed He/H2O atmospheric pressure plasmas

High-Speed Visualization of Filament Instabilities and Self-Organization Effect in RF Argon Plasma Jet at Atmospheric Pressure

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