Bulletin of the American Physical Society
63rd Annual Gaseous Electronics Conference and 7th International Conference on Reactive Plasmas
Volume 55, Number 7
Monday–Friday, October 4–8, 2010; Paris, France
Session TF3: Self Organization and Diagnostics in High Pressure Plasmas |
Hide Abstracts |
Chair: Svetlana Starikovskaya, LPP, Ecole Polytechnique, France Room: 162 |
Friday, October 8, 2010 10:30AM - 10:45AM |
TF3.00001: Simulations of pattern formation in DBDs Ananth Bhoj, Vladimir Kolobov Dielectric Barrier Discharges (or DBDs) are used in a variety of applications from ozone generation to plasma display panels to materials processing. DBDs occur in various forms depending on conditions such as pressure, gap length, applied voltage, frequency and gas composition. In some cases, the discharge is homogenous while in other cases it may consist of several filaments. With the latter kind, a seemingly self-organized pattern of filaments is observed in several instances. In this work, we use a 3D hydrodynamic model to investigate pattern formation in dielectric barrier discharges generated in Helium. An experimental setup similar to [1] is modeled with parallel glass plates connected to plane exterior electrodes, one of which is powered. The model addresses Poisson's equation for electric potential in the domain, multi-species charge transport equations in the discharge and the surface charge balance on dielectrics. Results from these simulations including the effect of varying discharge conditions (such as pressure, gap length, voltage and dielectric properties) on the generated patterns will be discussed. \\[4pt] [1] L. Stollenwerk, Sh. Amiranashvili, J.-P.Boeuf and H.-G. Purwins, Phys. Rev. Lett., 96, 255001 (2006). [Preview Abstract] |
Friday, October 8, 2010 10:45AM - 11:00AM |
TF3.00002: Physics and dynamics of filamentary patterns in dielectric barrier discharges J.P. Boeuf, B. Bernecker, T. Callegari Dielectric Barrier Discharges (DBDs) can exhibit filamentary structures that are characteristic of a particular class of 2-component reaction-diffusion systems called activator-inhibitor where one component stimulates the production of both components while the other one inhibits their growth. Numerical models predict the formation of self-organized filamentary structures in DBDs and suggest that the ion density in the sheath of a filament plays the role of the activator while the surface charges play the role of the inhibitor. We present studies of dynamic phenomena wherein the filaments do not form at the same space location at each half-cycle but are shifted by half a spatial period, leading to a new stable structure (quincunx). This is due to the existence of residual charges in the discharge volume between filaments at the end of a discharge pulse. We show that the combined effect of remaining surface charges and volume charges may be responsible for many dynamic phenomena, i.e. motion, repulsion, annihilation, and generation of filaments. Moving, localized solutions which remain stable cannot be obtained in the framework of 2-component activator-inhibitor models. However such solutions can be obtained from a 3-component activator-inhibitor model including the volume charge density remaining from the previous discharges, as a third component of the system. [Preview Abstract] |
Friday, October 8, 2010 11:00AM - 11:15AM |
TF3.00003: Modelling self-organization in DC glow microdischarges in xenon and argon P.G.C. Almeida, M.S. Benilov, M.J. Faria Self-organized patterns of multiple cathodic spots have been observed in DC glow microdischarges in xenon, but not in other gaseous systems. Recently, a hypothesis has been suggested that these patterns are described by multiple solutions existing at the same discharge current in the theory of glow discharges and such solutions have been found for the case of xenon in the framework of the simplest self-consistent model, which accounts for only one ionic species. However, the question why have the patterns been observed only in xenon microdischarges remains open. In this work, multiple solutions are studied in the framework of a more realistic model of DC glows in xenon and argon, which accounts for two ionic species, several ionization channels, and non-equilibrium population of excited states. It is shown that the conditions of argon microdischarges are less favorable for the existence of multiple solutions and, therefore, for self-organization. [Preview Abstract] |
Friday, October 8, 2010 11:15AM - 11:30AM |
TF3.00004: Role of adsorbed charges in breakdown and propagation of surface streamers Olivier Guaitella, Ilya Marinov, Binjie Dong, Fran\c{c}ois Pechereau, Anne Bourdon, Antoine Rousseau Streamer propagation is quite well understood in gas phase but still barely understood onto surfaces, in spite of their key role in many applications of atmospheric pressures discharges. This work aim at comparing the results of three different experimental setups devoted to charges deposition on dielectric surfaces and their consequences on breakdown processes, and influence on streamer propagation in air. Two different geometry of surface dielectric barrier discharges (sDBD) are used for i) studying importance of charges photo-desorption for starting breakdown, ii) making a correlation between fast imaging and charge deposition during propagation. The third reactor aims to constraint streamer into capillary tubes with charges already adsorbed on the wall. The relatively low energy of charges adsorption appears to significantly modify streamer development for DBD in continuous regime. [Preview Abstract] |
Friday, October 8, 2010 11:30AM - 11:45AM |
TF3.00005: Chaotic behavior in atmospheric pressure barrier discharges James Walsh, Felipe Iza, Natalia Janson, Michael Kong Atmospheric pressure discharges are an essential tool in many emerging industrial and biomedical applications.[1] To ensure process repeatability, it is critical to have a clear understanding of the discharge physics which in-turn allows the implementation of a control strategy. Recently, experimental work investigating dielectric barrier helium plasma jets highlighted the potential for chaotic behavior over a wide range of input powers.[2] Here we extend that work and examine the manifestation of chaotic behavior in a parallel plate discharge operated in both helium and argon gas. The power spectral density, phase-space representations and Poincar\'{e} sections are used to characterize the dynamics of the system and to obtain a deeper insight into its chaotic behavior. By examining two variables, namely the discharge current and electrode spacing, it is possible to map regions of chaotic, quasi-periodic, and periodic behavior over a wide range of operating conditions, providing an indirect control strategy to ensure a repeatable operation. The origins of chaotic behavior and the possible routes to chaos are examined using time resolved electrical and optical diagnostics and this information can be used to implement advanced control strategies. [1] Morfill \textit{et al.} New Journal of Physics 11 (2009) 115011 [2] Walsh \textit{et al.} J. Phys. D: Appl. Phys. 43 (2010) 075201 (14pp) [Preview Abstract] |
Friday, October 8, 2010 11:45AM - 12:00PM |
TF3.00006: Initial Distribution of Gas Density as a Method to Control the Radiation Characteristics of a High-Current Pulse Discharge Vladimir Zaitsev, Ivan Barykov, Aleksy Boldarev, Georgy Volkov The plasma pinch (current I$_{max}$ = 250 kA, rise time T = 1 $\mu$s) on the basis of a gas jet with special density distribution is described. The gas jet was produced by means of a pulse gas valve with a nozzle that was capable of forming a gas flow with a maximum density in the center of the discharge gap. The diagnostic techniques involved measurements of the discharge current and the pinch voltage, the size of the radiation area and the X-ray intensity. The experiments with different gases (Ar, Ne and N) showed that as a result of the discharge at this gas distribution the hot plasma area of ``point'' form (its typical size is 100 $\mu$m and life-time 3-5 ns) arises in the middle of the discharge gap. This area is the X-ray source of energy of quanta 50-5000 eV. The radiation spectrum depends on the gas type. The experimental results are presented. [Preview Abstract] |
Friday, October 8, 2010 12:00PM - 12:15PM |
TF3.00007: Development of a Laser Thomson Scattering Diagnostics System for Dielectric Barrier Discharge Plasmas Nima Bolouki, Kentaro Tomita, Yukihiko Yamagata, Kiichiro Uchino Dielectric barrier discharge is a type of discharge at around atmospheric pressure. The presence of dielectric layer on electrode leads to the formation of enormous micro discharges of nanoseconds between two electrodes. Characteristics of the DBD plasmas have not yet been understood well. That is because diagnostics of micro discharges forming the DBD plasmas are very difficult due to their short life times ($<$ 100 ns) and small sizes ($<$ 100 $\mu $m). In this paper, we created DBD plasmas in needle-hemispherical structure. Teflon layer as a dielectric is coated on hemispherical electrode. In order to obtain DBD plasma parameters, we have been trying to apply the LTS method to DBD plasmas. [Preview Abstract] |
Friday, October 8, 2010 12:15PM - 12:30PM |
TF3.00008: Spatiotemporal structure of electron density inside atmospheric pressure glow discharge measured by spectroscopic methods Keiichiro Urabe, Osamu Sakai, Kunihide Tachibana We have investigated discharge mechanisms in an atmospheric pressure glow discharge (APGD) by spectroscopic diagnostics. The APGD was a parallel-plate electrode configuration and generated in He gas with small N$_{2}$ impurity. We measured electron density ($n_{e})$ distributions by using a combination method of a CO$_{2}$-laser heterodyne interferometry and a millimeter-wave transmission. To discuss the formation mechanisms of $n_{e}$ distribution, we also measured spatiotemporal structures of He metastable atom density by a laser absorption spectroscopy (LAS) method, and calculated a dependence of ionization frequency on the N$_{2}$ impurity ratio. The measurement results of the combination method revealed that the spatial $n_{e}$ distribution was localized near the dielectric barrier, and the distribution was more broaden only at 0.25{\%} of N$_{2}$ impurity ratio. In the LAS measurement, we observed a typical structure of glow discharge in the APGD. This result indicates that the localization of $n_{e}$ distribution is due to the formation of negative glow region. The calculation results of the ionization frequency give us the explanation for the broaden $n_{e}$ distribution at 0.25{\%} of N$_{2}$ impurity ratio, which is the enhanced ionization in the range of lower reduced electric field. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700