Diagnostics of atmospheric-pressure pulsed-dc discharge with metal and liquid anodes by multiple laser-aided methods

Keiichiro Urabe, Naoki Shirai, Kentaro Tomita, Tsuyoshi Akiyama, Tomoyuki Murakami

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Abstract

The density and temperature of electrons and key heavy particles were measured in an atmospheric-pressure pulsed-dc helium discharge plasma with a nitrogen molecular impurity generated using system with a liquid or metal anode and a metal cathode. To obtain these parameters, we conducted experiments using several laser-aided methods: Thomson scattering spectroscopy to obtain the spatial profiles of electron density and temperature, Raman scattering spectroscopy to obtain the neutral molecular nitrogen rotational temperature, phase-modulated dispersion interferometry to determine the temporal variation of the electron density, and time-resolved laser absorption spectroscopy to analyze the temporal variation of the helium metastable atom density. The electron density and temperature measured by Thomson scattering varied from 2.4 1014 cm-3 and 1.8 eV at the center of the discharge to 0.8 1014 cm-3 and 1.5 eV near the outer edge of the plasma in the case of the metal anode, respectively. The electron density obtained with the liquid anode was approximately 20% smaller than that obtained with the metal anode, while the electron temperature was not significantly affected by the anode material. The molecular nitrogen rotational temperatures were 1200 K with the metal anode and 1650 K with the liquid anode at the outer edge of the plasma column. The density of helium metastable atoms decreased by a factor of two when using the liquid anode.

Original languageEnglish
Article number045004
JournalPlasma Sources Science and Technology
Volume25
Issue number4
DOIs
Publication statusPublished - May 26 2016

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All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

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