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Title: Emission spectroscopy of a microhollow cathode discharge plasma in helium-water gas mixtures

Abstract

A dc microhollow cathode discharge (MHCD) plasma was generated inflowing helium gas containing water vapor. The cathode hole diameters were 0.3, 0.7, 1.0, and 2.0 mm, each with a length of 2.0 mm. Emission spectroscopy was carried out to investigate the discharge mode and to determine the plasma parameters. For the 0.3-mm cathode, stable MHCDs in an abnormal glow mode existed at pressures up to 100 kPa, whereas for larger diameters, a plasma was not generated at atmospheric pressure. An analysis of the lineshapes relevant to He at 667.8 nm and to H{alpha} at 656.3 nm implied an electron density and gas temperature of 2 x 10{sup 14} cm{sup -3} and 1100 K, respectively, for a 100-kPa discharge in the negative glow region. The dependence of the OH band, and H{alpha} intensities on the discharge current exhibited different behaviors. Specifically, the OH spectrum had a maximum intensity at a certain current, while the H atom intensity kept increasing with the discharge current. This observation implies that a high concentration of OH radicals results in quenching, leading to the production of H atoms via the reaction OH + e{sup -}{yields} O + H + e{sup -}.

Authors:
; ; ; ; ;  [1]
  1. Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527 (Japan)
Publication Date:
OSTI Identifier:
22036733
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 110; Journal Issue: 7; Other Information: (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 74 ATOMIC AND MOLECULAR PHYSICS; ATOMS; CATHODES; ELECTRIC CURRENTS; ELECTRON DENSITY; ELECTRON TEMPERATURE; ELECTRONS; EMISSION SPECTROSCOPY; GLOW DISCHARGES; HELIUM; HYDROXYL RADICALS; ION TEMPERATURE; MIXTURES; PLASMA; PLASMA DENSITY; PLASMA DIAGNOSTICS; PLASMA INSTABILITY; PLASMA PRESSURE; WATER VAPOR

Citation Formats

Namba, S., Yamasaki, T., Hane, Y., Fukuhara, D., Kozue, K., and Takiyama, K. Emission spectroscopy of a microhollow cathode discharge plasma in helium-water gas mixtures. United States: N. p., 2011. Web. doi:10.1063/1.3646551.
Namba, S., Yamasaki, T., Hane, Y., Fukuhara, D., Kozue, K., & Takiyama, K. Emission spectroscopy of a microhollow cathode discharge plasma in helium-water gas mixtures. United States. doi:10.1063/1.3646551.
Namba, S., Yamasaki, T., Hane, Y., Fukuhara, D., Kozue, K., and Takiyama, K. Sat . "Emission spectroscopy of a microhollow cathode discharge plasma in helium-water gas mixtures". United States. doi:10.1063/1.3646551.
@article{osti_22036733,
title = {Emission spectroscopy of a microhollow cathode discharge plasma in helium-water gas mixtures},
author = {Namba, S. and Yamasaki, T. and Hane, Y. and Fukuhara, D. and Kozue, K. and Takiyama, K.},
abstractNote = {A dc microhollow cathode discharge (MHCD) plasma was generated inflowing helium gas containing water vapor. The cathode hole diameters were 0.3, 0.7, 1.0, and 2.0 mm, each with a length of 2.0 mm. Emission spectroscopy was carried out to investigate the discharge mode and to determine the plasma parameters. For the 0.3-mm cathode, stable MHCDs in an abnormal glow mode existed at pressures up to 100 kPa, whereas for larger diameters, a plasma was not generated at atmospheric pressure. An analysis of the lineshapes relevant to He at 667.8 nm and to H{alpha} at 656.3 nm implied an electron density and gas temperature of 2 x 10{sup 14} cm{sup -3} and 1100 K, respectively, for a 100-kPa discharge in the negative glow region. The dependence of the OH band, and H{alpha} intensities on the discharge current exhibited different behaviors. Specifically, the OH spectrum had a maximum intensity at a certain current, while the H atom intensity kept increasing with the discharge current. This observation implies that a high concentration of OH radicals results in quenching, leading to the production of H atoms via the reaction OH + e{sup -}{yields} O + H + e{sup -}.},
doi = {10.1063/1.3646551},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 7,
volume = 110,
place = {United States},
year = {2011},
month = {10}
}