Bulletin of the American Physical Society
69th Annual Gaseous Electronics Conference
Volume 61, Number 9
Monday–Friday, October 10–14, 2016; Bochum, Germany
Session DT2: Computational Plasma Modeling |
Hide Abstracts |
Chair: Laxminarayan Raja, University of Texas Room: 2a |
Tuesday, October 11, 2016 8:30AM - 8:45AM |
DT2.00001: Multicomponent Transportmodel for Normal-Pressure Plasmas: Modelling and Numerical Methods Juergen Geiser We are motivated to model and simulate multicomponent transport models for cold atmospheric plasmas (CAPs). Such problems are related to the atmospheric pressure and room-temperature regimes. The plasmas are weakly ionized and have high relations of radical concentrations, e.g., oxygen, which are important for applications on surface-modifications. We derive a model based on multicomponent plasma regimes, while. each single species influences the flux-characteristics and the characteristic of the mixture, i.e., the diffusive effects of each specie are important. We assume that in the temperature- and pressure-regimes, the particles have small characteristic length instead of the length in the apparatus and we can derive and apply macroscopic equations. We extend the multicomponent systems (plasma-model) with the Stefan-Maxwell (SM) equation instead of a standard Fickian approach, while we assume to deal with non-dominant gaseous species. For solving such delicate nonlinear SM equations, we propose new iterative splitting methods based on the relaxation approaches. The novel solver methods are tested with multicomponent models in the literature. [Preview Abstract] |
Tuesday, October 11, 2016 8:45AM - 9:00AM |
DT2.00002: ABSTRACT WITHDRAWN |
Tuesday, October 11, 2016 9:00AM - 9:15AM |
DT2.00003: Semi-analytical description of arbitrary electron energy distribution function for non-kinetic models Wladislaw Dobrygin, Oliver Schmidt, Ralf Peter Brinkmann An efficient way to study chemistry and fundamental processes of plasmas is a global (volume averaged) chemical model. The process conditions (absorbed power, pressure), the plasma chemistry and the shape of electron energy distribution function (EEDF) are the crucial model input parameters. Langmuir probe measurements of EEDF in very well-known reactors like ICP shows non-maxwellian distributions[1]. In order to solve the global models of this kind of plasmas without solving a Boltzmann-equation, the EEDF with parametric mean energy have to be described by an analytic function (i.e. Maxwell- or Druyvesteyn distribution). If the EEDF has a convex shape, Druyvesteyn-like distributions with modified exponent x can be used [2] but others such as the bi-Maxwellian distribution cannot. In this work, we show a way to represent an arbitrary EEDF using a semi-analytical function which allows us to variate the mean energy of the EEDF. The EEDF shape is given from Langmuir probe measurement. The validation will be shown in calculations of low pressure ICP discharge in Argon and Acetylene chemistry. \\[1ex] [1] V. A. Godyak et al., Plasma Sources Sci. Technol. \textbf{11} 525-543 (2002) \\[0ex] [2] J. T. Gudmundsson, Plasma Sources Sci. Technol. \textbf{10} 76-81 (2001) [Preview Abstract] |
Tuesday, October 11, 2016 9:15AM - 9:30AM |
DT2.00004: Effect of a momentum-transfer scattering at inelastic collisions on the electron transport II: Case study in Ar Naohiko Shimura, Takashi Yagisawa, Toshiaki Makabe In the previous paper, we presented an expression for the inelastic momentum-transfer scattering on the collision integral of the Boltzmann equation, in order to reflect the effect of an inelastic scattering distribution of an electron with a molecule on the electron kinetics in gases and collisional plasmas 1]. In the present paper we will discuss the influence of the anisotropic scattering of the inelastic collisions on the electron velocity distribution in Ar with a scattering distribution of cosT. The numerical procedure is based on our Direct Numerical Procedure of the Boltzmann equation 2]. A comparison of the electron velocity distribution between of the anisotropic scattering and isotropic one in an rf-field will give us a renewed interest in the electron transport in gases and collisional plasmas. 1. T. Makabe and R. White, J. Phys. D: Appl. Phys. 48(2015) 485205. 2. T. Makabe and Z. Petrovic, Plasma Electronics (2nd edn.), CRC Press (2015). [Preview Abstract] |
Tuesday, October 11, 2016 9:30AM - 9:45AM |
DT2.00005: Validation and Verification of Two Particle-In-Cells Codes for a Glow Discharge Alexander Khrabrov, Johan Carlsson, Igor Kaganovich, Timothy Sommerer Two PIC codes, a research code EDIPIC and a commercial LSP, were benchmarked and validated for a parallel-plate glow discharge in helium, in which the axial electric field profile had been carefully mapped in experiment [1]. Both codes reproduce very well the cathode fall and the negative glow regions of the discharge, including formation of high density plasma with very low-energy (0.1 eV) electrons in the negative glow. A detailed comparison was performed for several synthetic cases of electron-beam injection into helium gas and showed that the codes are in excellent agreement for ionization rate, as well as for collisional transport if isotropic scattering was assumed. However, the electron velocity distribution is anisotropic in the cathode fall; hence an adequate model of anisotropic scattering in elastic/inelastic collisions needs to be adopted. Because of the experimental uncertainty for the emission yield, it is tuned to make the cathode current computed by each code match the experimental values. The resulting computed electric fields are in excellent agreement with each other and within about 10{\%} of the experimental value. In the process of validation, several issues with each of the codes were noted and addressed, including the necessity to use quality random number generators, and, for the commercial code, updating the field solver, the secondary electron emission, and the external circuit algorithms. [1] E A den Hartog, D A Doughty and J E Lawler, Physical Review A \textbf{38}, 2471 (1988). [Preview Abstract] |
Tuesday, October 11, 2016 9:45AM - 10:00AM |
DT2.00006: Incorporation of the electron energy equation into the hybrid Monte Carlo - fluid model for glow discharge: the applicability and reliability of the model Ender Eylenceoglu, Ismail Rafatov, Anatoly Kudryavtsev A modification of the conventional hybrid Monte Carlo - fluid model for glow discharge, which incorporates the electron energy equation, is considered. In the proposed model electrons are separated into two groups, namely, high energetic fast and low energetic slow (bulk) electrons. Density profiles of ions, slow electrons, and meta-stable particles are determined from the solution of corresponding continuity equations. Fast electrons, which are responsible for ionization and excitation events in the discharge, are simulated by the Monte-Carlo method. The temperature profile for slow electrons is obtained from the solution of the energy balance equation. The transport (mobility and diffusion) coefficients as well as the reaction rates for slow electrons are determined as functions of the electron temperature. Test calculations are carried out for the direct current glow discharge in argon within two-dimensional geometry. Comparison of the computed results with those obtained from the conventional fluid and hybrid models and the experimental data is done, the applicability and reliability of the proposed model is studied in details. [Preview Abstract] |
Tuesday, October 11, 2016 10:00AM - 10:15AM |
DT2.00007: plasmaFoam: An OpenFOAM framework for computational plasma physics and chemistry Ayyaswamy Venkattraman, Abhishek Kumar Verma As emphasized in the 2012 Roadmap for low temperature plasmas (LTP), scientific computing has emerged as an essential tool for the investigation and prediction of the fundamental physical and chemical processes associated with these systems. While several in-house and commercial codes exist, with each having its own advantages and disadvantages, a common framework that can be developed by researchers from all over the world will likely accelerate the impact of computational studies on advances in low-temperature plasma physics and chemistry. In this regard, we present a finite volume computational toolbox to perform high-fidelity simulations of LTP systems. This framework, primarily based on the OpenFOAM solver suite, allows us to enhance our understanding of multiscale plasma phenomenon by performing massively parallel, three-dimensional simulations on unstructured meshes using well-established high performance computing tools that are widely used in the computational fluid dynamics community. In this talk, we will present preliminary results obtained using the OpenFOAM-based solver suite with benchmark three-dimensional simulations of microplasma devices including both dielectric and plasma regions. We will also discuss the future outlook for the solver suite. [Preview Abstract] |
Tuesday, October 11, 2016 10:15AM - 10:30AM |
DT2.00008: Particle in Cell/Monte Carlo Collision Analysis of the Problem of Identification of Impurities in Gas within the Plasma Electron Spectroscopy Method Cemre Kusoglu Sarikaya, Ismail Rafatov, Anatoly Kudryavtsev Particle in Cell/Monte Carlo Collision (PIC/MCC) analysis of the problem of identification of impurities in gas within the Plasma Electron Spectroscopy (PLES) method is carried out. The idea of the PLES is based on the analysis of the effect on the EEDF due to electrons, released in the Penning reactions between the metastable atoms of working gas and impurity. $1d3v$ PIC/MCC numerical code is developed and verified under the conditions of RF capacitively coupled discharge in helium. The efficiency of the code was increased by its parallelization using Open MPI. Test calculations showed that the efficiency of the code increases about $70$ times with increase of the number of cores up to 95. Simulations have been done for DC glow discharge in helium doped by the small amount of argon. The elastic, excitation and ionization collisions between electron-neutral pairs and isotropic scattering and charge exchange collisions between ion-neutral pairs and Penning ionizations are taken into account. PIC/MCC numerical model is incorporated with equations for density of the metastable helium atoms in the fluid approximation. Numerical results are consistent well with the theoretical analysis of formation of nonlocal EEDF and existing experimental data. [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