DocumentCode :
3504825
Title :
Simulations of plasmas of positive column in rare gases
Author :
Bogdanov, Evgeny ; Kudryavtsev, Anatoly A. ; Arslanbekov, R.R. ; Kolobov, V.I.
Author_Institution :
St. Petersburg Univ., Russia
fYear :
2004
fDate :
1-1 July 2004
Firstpage :
249
Abstract :
Summary form only given. Positive Column (PC) plasma has found various applications especially in lighting industry. We have applied a comprehensive discharge model to revisit physical phenomena in collisional plasmas of rare gases. The computational model includes an electron Boltzmann solver based on two-term spherical harmonics expansion of the distribution function, continuum model of ions, neutral and excited atoms, and an equation for gas temperature. The Poisson equation is solved to resolve the radial distribution of the electrostatic potential and the sheath structure. The axial electric field is calculated self-consistently for a given discharge current. Simulations are performed in a wide range of gas pressures (pR=0.1-100 Torr cm) and a wide range of discharge currents from diffusion controlled to recombination controlled regimes. Among the physical phenomena studied in this work are specifics of electron kinetics for different operating conditions, radial constriction of plasma with increasing gas pressures and currents, and effects of gas heating on the discharge structure in different gases (Argon, Neon, Helium). We discuss in details the importance of nonlocal effects and Coulomb collisions for electron kinetics under different conditions, and details of chemistry models on plasma structure and composition. In particular, we clarify the relative importance of electron kinetics, metastable atom kinetics and gas heating on discharge constriction in different gases. We also study transition from ambipolar to free electron diffusion at small discharge currents, specifically important for capillar (micro) discharges. We calculate different types of current-voltage characteristics and compare with available experimental data.
Keywords :
Poisson equation; argon; discharges (electric); helium; neon; plasma collision processes; plasma sheaths; plasma simulation; 0.1 to 100 torr; Ar; Coulomb collisions; He; Ne; Poisson equation; argon; axial electric field; capillar discharges; chemistry models; collisional plasmas; computational model; continuum model; current-voltage characteristics; discharge current; discharge structure; distribution function; electron Boltzmann solver; electron kinetics; electrostatic potential; excited atoms; free electron diffusion; gas pressures; gas temperature; gases; helium; lighting industry; microdischarges; neon; neutral atoms; plasma simulation; plasma structure; positive column plasma; sheath structure; two-term spherical harmonics expansion; Computational modeling; Electrons; Gases; Kinetic theory; Plasma applications; Plasma chemistry; Plasma simulation; Plasma temperature; Poisson equations; Pressure control;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Plasma Science, 2004. ICOPS 2004. IEEE Conference Record - Abstracts. The 31st IEEE International Conference on
Conference_Location :
Baltimore, MD, USA
ISSN :
0730-9244
Print_ISBN :
0-7803-8334-6
Type :
conf
DOI :
10.1109/PLASMA.2004.1339876
Filename :
1339876
Link To Document :
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