Multilayer plasma patterns in paralleled and coupled atmospheric glow discharges

Yang, Yun Jung; Shi, Jian; Harry, J. E.; Proctor, J.; Garner, Colin P.; Kong, Michael G.

doi:10.1109/tps.2005.845099

Cited by 15 publications

(7 citation statements)

References 9 publications

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“…Assuming that K iz (x) and X(x) are related by (19), a local calculation using Bolsigþ 12 yields q % 2. 5 This would lead to stability and the absence of striations according to condition (27). This suggests that, as in the steady-state global model, non-local kinetic effects are required for instability.…”

Section: Nonlocal Kineticsmentioning

confidence: 97%

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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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Section: Nonlocal Kineticsmentioning

confidence: 97%

“…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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“…The self-organized formation of spatial patterns of the light emission has been an attractive topic of fundamental research due to its remarkable influence on various plasma systems ranging from atmospheric to low pressure DC/RF discharges [1][2][3][4][5][6][7][8][9][10]. It is well known that the self-organized discharge structures can be generally divided into two broad categories.…”

Section: Introductionmentioning

confidence: 99%

Striations in electronegative capacitively coupled radio-frequency plasmas: analysis of the pattern formation and the effect of the driving frequency

Liu

Korolov

Schüngel

et al. 2017

Plasma Sources Sci. Technol.

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Self-organized striated structures of the plasma emission have recently been observed in capacitive radiofrequency CF 4 plasmas by Phase Resolved Optical Emission Spectroscopy (PROES) and their formation was analyzed and understood by Particle in Cell / Monte Carlo Collision (PIC/MCC) simulations [Y.-X.Liu, et al. Phys. Rev. Lett. 116, 255002 (2016)]. The striations were found to result from the periodic generation of double layers due to the modulation of the densities of positive and negative ions responding to the externally applied RF potential. In this work, an in-depth analysis of the formation of striations is given, as well as the effect of the driving frequency on the plasma parameters, such as the spatially modulated charged species densities, the electric field, and the electron power absorption is studied by PROES measurements, PIC/MCC simulations, and an ion-ion plasma model. The measured spatiotemporal electronic excitation patterns at different driving frequencies show a high degree of consistency with the simulation results. The striation gap (i.e., the distance between two ion density maxima) is found to be inversely proportional to the driving frequency. In the presence of striations the minimum (CF 3 + , F − ) ion densities in the bulk region exhibit an approximately quadratic increase with the driving frequency. For these densities, the eigenfrequency of the ion-ion plasma is near the driving frequency, indicating that a resonance occurs between the positive and negative ions and the oscillating electric field inside the plasma bulk. The maximum ion densities in the plasma bulk are found not to exhibit a simple dependence on the driving frequency, since these ion densities are abnormally enhanced within a certain frequency range due to the ions being focused into the "striations" by the spatially modulated electric field inside the bulk region.2 / 31 Striations in electronegative capacitively coupled radio-frequency plasmas: analysis of the pattern formation and the effect of the driving frequency 2 / 31 deposition (PECVD) -often performed at relatively high pressures, low driving frequencies, and in electronegative gasessince the striations can drastically affect various process relevant plasma parameters, e.g., the flux-energy distribution functions of different charged species.One of the most well-known scenarios is the self-organized striated structure occurring in the positive column region of dc glow discharges, wherein ion-acoustic or ionization waves are generally considered to be responsible for their appearance [1,[11][12][13]. Over the past few years, several types of striated structures have been observed in different versions of atmospheric pressure plasma jets (APPJ). Depending on the discharge conditions, the plasma streamer ejected from the nozzle was found in [14,15] to be stratified into stationary bright and dark slender regions between the nozzle and the target plate. Very recently, a stratified filament occurring in the discharge tube of a RF argon APPJ was observed in num...

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“…[11] Self-organization in gas discharges may occur as unstructured and localized patterns, often known as traveling spots [12,13] or as a static striate pattern formed along the length of the discharge plasma. [14] In the time domain, these spatial discharge structures may appear periodically or chaotically. [15,16] Complex spatial patterns in DBD are scientifically both interesting and important as their understanding is critical to the development of their diagnostics methodologies and their industrial applications.…”

Section: Introductionmentioning

confidence: 99%

Concentric-ring structures in an atmospheric pressure helium dielectric barrier discharge

et al. 2011

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This paper performs a numerical simulation of concentric-ring discharge structures within the scope of a twodimensional diffusion-drift model at atmospheric pressure between two parallel circular electrodes covered with thin dielectric layers. With a relative high frequency the discharge structures present different appearances of ring structures within different radii in time due to the evolvement of the filaments. The spontaneous electron density distributions help understanding the formation and development of self-organized discharge structures. During a cycle the electron avalanches are triggered by the electric field strengthened by the feeding voltage and the residual charged particles on the barrier surface deposited in the previous discharges. The accumulation of charges is shown to play a dominant role in the generation and annihilation of the discharge structures. Besides, the rings split and unify to bring and annihilate rings which form a new discharge structure.

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Multilayer plasma patterns in paralleled and coupled atmospheric glow discharges

Cited by 15 publications

References 9 publications

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

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

Striations in electronegative capacitively coupled radio-frequency plasmas: analysis of the pattern formation and the effect of the driving frequency

Concentric-ring structures in an atmospheric pressure helium dielectric barrier discharge

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