Mode Characteristics of radio-frequency atmospheric glow discharges

Shi, Jianjun; Kong, Michael G.

doi:10.1109/tps.2005.844527

Cited by 68 publications

(10 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They conducted experiments for both argon and helium gases and also reported the effect of gas impurities on the discharge characteristics. Several modeling studies [16][17][18][19][20] have been conducted to obtain understanding of the plasma dynamics, dominant physical and chemical mechanism and structure of the rf ccp discharges. A one-dimensional self-consistent fluid model was developed by Yuan and Raja [16] to study atmospheric pressure glow discharges in helium.…”

Section: Introductionmentioning

confidence: 99%

“…They reported the effect of nitrogen impurities and interelectrode gap width to the discharge characteristics. Shi and Kong [17] developed a one-dimensional self-consistent hybrid model for a rf helium glow discharge. The model predicted the observance of α and γ modes [17] and identified volumetric and localized gas ionization to be the dominant mechanism for the α and γ modes, respectively [18].…”

Section: Introductionmentioning

confidence: 99%

“…Shi and Kong [17] developed a one-dimensional self-consistent hybrid model for a rf helium glow discharge. The model predicted the observance of α and γ modes [17] and identified volumetric and localized gas ionization to be the dominant mechanism for the α and γ modes, respectively [18]. The effect of plasma excitation frequency on the plasma stability was studied by Shi and Kong [19].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Atmospheric pressure radio frequency glow discharges in argon: effects of external matching circuit parameters

Farouk¹,

Farouk²,

Gutsol³

et al. 2008

Plasma Sources Sci. Technol.

View full text Add to dashboard Cite

Numerical simulations of radio frequency atmospheric pressure argon glow discharges were performed using a one-dimensional hybrid model. The discharge simulations were carried out for a parallel plate electrode configuration with an inter-electrode gap of 1.0 mm together with an external matching circuit. The external matching circuit parameters were found to have significant effect on the discharge characteristics. The results indicate that the discharge can operate at either the α or γ mode depending on the matching circuit parameters. The two modes of operation were found to be distinctly different. The predicted Ar * density was considered to provide qualitatively the visual appearance of the α or γ mode discharge. The α mode was found to have a luminous region in the center of the discharge. On the other hand, the γ mode had luminous regions very close to the electrodes which were followed by alternating dark and bright regions. The appearance of the simulated γ mode was found to resemble that of an atmospheric pressure direct current glow discharge. The predicted gas temperature indicated the γ mode to have higher gas temperature compared with the α mode.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Atmospheric pressure radio frequency glow discharges in argon: effects of external matching circuit parameters

Farouk¹,

Farouk²,

Gutsol³

et al. 2008

Plasma Sources Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…In order to determine the plasma sheath in microdischarges, Shi and Kong derived a 14% reduction rule on the electric field distribution to define the plasma sheath thickness in both direct-current (DC) and radio-frequency (RF) discharges. 18,19 The 14% rule determines the sheath thickness as the distance between the cathode surface and the spatial position where the cathode electric field is at a magnitude that is 14% of the electric field at the cathode surface. This is in the region near the cathode where a linear electric filed distribution is valid.…”

Section: Introductionmentioning

confidence: 99%

Effect of surface protrusion on plasma sheath properties in atmospheric microdischarges

Zhang

Verboncoeur

et al. 2018

Physics of Plasmas

View full text Add to dashboard Cite

The electric field enhancement due to the presence of cathode surface protrusion is investigated in atmospheric microdischarges with the goal of identifying the plasma sheath properties (such as cathode sheath thickness and electric field distortion). The electric field enhancement caused by surface protrusion is examined by adjusting the aspect ratio and the protrusion size. It is found that the cathode electric field enhancement depends strongly (weakly) on the aspect ratio (size) of the protrusion when it is much smaller than the discharge gap distance. In particular, the axial electric field in both vacuum and discharges becomes nonlinear with the protrusion on the cathode. The cathode sheath thicknesses obtained by two different methods are compared. With the same axial (or radial) protrusion dimension, increasing the aspect ratio will result in a significant decrease in the sheath thickness, whereas increasing the axial protrusion size with an unchanged aspect ratio will only lead to a slight decrease in the sheath thickness. The results contribute to predicting the relative plasma sheath properties from the geometrical parameter of the surface protrusion in atmospheric microdischarges.

show abstract

“…The sheath thickness is obtained by estimating the distance over which the electric field reduces from its top value to less than 10% of the peak field. 13 At a given current density of 0.06 A/cm 2 , while the electrode gap is raised, the sheath expands initially, then its thickness almost keeps a constant value of approximately 215 lm when the electrode spacings exceed 500 lm. However from Fig.…”

mentioning

confidence: 95%

The recovery of glow-plasma structure in atmospheric radio frequency microplasmas at very small gaps

Zhang

Shang

2011

Physics of Plasmas

View full text Add to dashboard Cite

In atmospheric radio frequency discharges at 13.56 MHz, with the electrode gap reduced, the sheath region eventually occupies a main portion of the electrode spacing and the bulk plasma region is significantly compressed. The computational results in this letter based on a one-dimensional fluid model show that by increasing the excitation frequency over 13.56 MHz, the traditional glow-plasma structure could gradually recover even at very small sizes with a well defined quasineutral plasma region, and the electron density is improved but the electric fields in sheath region are reduced. This study indicates that the excitation frequency can be used to modulate the discharge structure and then tailor the plasma-surface interaction in atmospheric microplasmas.Atmospheric microplasmas have commanded much attention in recent years due to the considerable scientific depth and potential applications. 1-4 For atmospheric capacitively radio-frequency (rf) discharges, when the electrode gaps are confined to submillimeter dimensions, the generated microplasmas show many unique properties compared to the large-scale atmospheric plasmas, 3 such as the high energetic electrons, 5 different discharge structures, 6,7 and nonequilibrium characters. 8 The experimental 6 and computational studies 5,7 have demonstrated that in atmospheric rf discharges at 13.56 MHz, with the electrode gap reduced, the traditional glow-plasma (GP) structure will eventually transit to a new sheath-dominated-plasma (SDP) structure, where the sheath region occupies a large portion of the electrode gap and almost no distinct bulk plasma region develops. In a SDP structure, three electron groups with different electron temperatures have been revealed by the Particle-In-Cell (PIC) simulation and the high energetic electrons present a new way to interact with the electrodes or the given surfaces, moreover these electrons maybe contribute to the reactivity of atmospheric microplasmas. 5 The discharge modes in rf microplasmas have been discussed but still need to be further clarified by experiments and simulations. 5-7 Increasing frequency is widely accepted as a way to enhance the discharge stability and reduce the electron temperature at a constant power density. 10-12 Nevertheless, the frequency effects on the structure transition in atmospheric rf discharges are largely unexplored. Although the microplasmas in SDP regime show many advantages and the GP structure with quasineutral plasmas may still be very useful in many applications at very small sizes. The experimental diagnosis of atmospheric microplasmas, however, is facing many new challenges due to the small dimension and high gas pressure, 3,4 and numerical simulations provide a valuable alternative for investigating the properties of microplasmas. 2In this letter a one-dimensional fluid model is explored to study the transition of discharge structures in capacitively rf discharges at atmospheric pressure. 11,12 Briefly, the continuity equations with the drift-diffusion approximation are used to des...

show abstract

Mode Characteristics of radio-frequency atmospheric glow discharges

Cited by 68 publications

References 23 publications

Atmospheric pressure radio frequency glow discharges in argon: effects of external matching circuit parameters

Atmospheric pressure radio frequency glow discharges in argon: effects of external matching circuit parameters

Effect of surface protrusion on plasma sheath properties in atmospheric microdischarges

The recovery of glow-plasma structure in atmospheric radio frequency microplasmas at very small gaps

Contact Info

Product

Resources

About