Excited level populations and excitation kinetics of nonequilibrium ionizing argon discharge plasma of atmospheric pressure

Akatsuka, Hiroshi
April 2009
Physics of Plasmas;Apr2009, Vol. 16 Issue 4, p043502
Academic Journal
Population densities of excited states of argon atoms are theoretically examined for ionizing argon plasma in a state of nonequilibrium under atmospheric pressure from the viewpoint of elementary processes with collisional radiative model. The dependence of excited state populations on the electron and gas temperatures is discussed. Two electron density regimes are found, which are distinguished by the population and depopulation mechanisms for the excited states in problem. When the electron impact excitation frequency for the population or depopulation is lower than the atomic impact one, the electron density of the plasma is considered as low to estimate the population and depopulation processes. Some remarkable characteristics of population and depopulation mechanisms are found for the low electron density atmospheric plasma, where thermal relaxation by atomic collisions becomes the predominant process within the group of close-energy states in the ionizing plasma of atmospheric pressure, and the excitation temperature is almost the same as the gas temperature. In addition to the collisional relaxation by argon atoms, electron impact excitation from the ground state is also an essential population mechanism. The ratios of population density of the levels pairs, between which exists a large energy gap, include information on the electron collisional kinetics. For high electron density, the effect of atomic collisional relaxation becomes weak. For this case, the excitation mechanism is explained as electron impact ladderlike excitation similar to low-pressure ionizing plasma, since the electron collision becomes the dominant process for the population and depopulation kinetics.


Related Articles

  • Filamentation in argon microwave plasma at atmospheric pressure. Cardoso, R. P.; Belmonte, T.; Noël, C.; Kosior, F.; Henrion, G. // Journal of Applied Physics;May2009, Vol. 105 Issue 9, p093306 

    Filamentation in an argon plasma is studied using a microwave cavity at atmospheric pressure. We show that the size and gas temperature of the filaments increase with the power absorbed by the plasma. The appearance of an additional filament occurs at specific values of the absorbed power. Each...

  • Parametric study of atmospheric pressure microwave-induced Ar/O2 plasmas and the ambient air effect on the plasma. Moon, Se Youn; Choe, W. // Physics of Plasmas;Oct2006, Vol. 13 Issue 10, p103503 

    A torch type microwave-induced afterglow plasma was produced at atmospheric pressure using an open-ended fused silica concentric double tube assisted by Ar and O2 supply gases. The plasma emerged from the end of the discharge tube and was exposed to ambient air. A parametric study of the plasma...

  • Spectroscopic study of a long high-electron-density argon plasma column generated at atmospheric pressure. Shou-Zhe Li; Wen-Tong Huang; Dezhen Wang // Physics of Plasmas;Feb2010, Vol. 17 Issue 2, p020702 

    A stable plasma column is generated in a quartz tube using a pair of hollow electrodes driven by a sinusoidal power supply of 45 kHz at atmospheric pressure in argon. Two distinct operating modes (low-current and high-current modes) are identified through observing its discharge phenomena,...

  • Dynamics of plasma expansion and shockwave formation in femtosecond laser-ablated aluminum plumes in argon gas at atmospheric pressures. Miloshevsky, Alexander; Harilal, Sivanandan S.; Miloshevsky, Gennady; Hassanein, Ahmed // Physics of Plasmas;Apr2014, Vol. 21 Issue 4, p1 

    Plasma expansion with shockwave formation during laser ablation of materials in a background gasses is a complex process. The spatial and temporal evolution of pressure, temperature, density, and velocity fields is needed for its complete understanding. We have studied the expansion of...

  • Plasma properties downstream of a low-power Hall thruster. Beal, Brian E.; Gallimore, Alec D.; Hargus, William A. // Physics of Plasmas;Dec2005, Vol. 12 Issue 12, p123503 

    Triple Langmuir probes and emissive probes were used to measure the electron number density, electron temperature, and plasma potential downstream of a low-power Hall thruster. The results show a polytropic relation between electron temperature and electron number density throughout the sampled...

  • Metastable and charged particle decay in neon afterglow studied by the breakdown time delay measurements. Marković, V. Lj.; Gocić, S. R.; Stamenković, S. N.; Petrović, Z. Lj. // Physics of Plasmas;Oct2007, Vol. 14 Issue 10, p103504 

    Memory effect—the long time variation of the electrical breakdown time delay on the relaxation time [formula] in neon—was explained by the Ne(3P2) (1s5) metastable state remaining from the preceding glow [Dj. A. Bosˇan, M. K. Radovic, and Dj. M. Krmpotic, J. Phys. D 19, 2343...

  • An atmospheric-pressure, high-aspect-ratio, cold micro-plasma. Lu, X.; Wu, S.; Gou, J.; Pan, Y. // Scientific Reports;12/19/2014, p1 

    An atmospheric pressure nonequilibrium Ar micro-plasma generated inside a micro-tube with plasma radius of 3 μm and length of 2.7 cm is reported. The electron density of the plasma plume estimated from the broadening of the Ar emission line reaches as high as 3 × 1016 cm-3. The electron...

  • Spectroscopic Study of Microwave Induced Plasma. Jovićević, S. // AIP Conference Proceedings;2004, Vol. 740 Issue 1, p315 

    The results of the spatial distribution studies of electron densities, excitation and rotational temperatures and atomic line intensities of various elements in an atmospheric pressure mini-MIP torch with tangential argon flow. The electron number density, ne, is determined from the width of the...

  • The effect of gas flow on argon plasma discharge generated with a single-electrode configuration at atmospheric pressure. Shou-Zhe Li; Wen-Tong Huang; Dezhen Wang // Physics of Plasmas;Sep2009, Vol. 16 Issue 9, p093501 

    A long atmospheric-pressure plasma column confined in a dielectric tube is generated in argon with use of a single-electrode configuration driven with a sinusoidal power supply operating at 45 kHz. The electrical characteristics are investigated by means of measuring voltage-current and...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics