Title: Nanosecond pulsed humid Ar plasma jet in air: shielding, discharge characteristics and atomic hydrogen production

Abstract

Gas phase non-equilibrium plasmas jets containing water vapor are of growing interest for many applications. In this work, we report a detailed study of an atmospheric pressure nanosecond pulsed Ar + 0.26% H₂O plasma jet. The plasma jet operates in an atmospheric pressure air surrounding but is shielded with a coaxial argon flow to limit the air diffusion into the jet effluent core. The jet impinges on a metal plate electrode and produces a stable plasma filament (transient spark) between the needle electrode in the jet and the metal plate. The stable plasma filament is characterized by spatially and time resolved electrical and optical diagnostics. This includes Rayleigh scattering, Stark broadening of the hydrogen Balmer lines and two-photon absorption laser induced fluorescence (TaLIF) to obtain the gas temperature, the electron density and the atomic hydrogen density respectively. Electron densities and atomic hydrogen densities up to $$5 \times 10^{22}$$ $${\rm m}^{-3}$$ and $$2 \times 10^{22}$$ $${\rm m}^{-3}$$ have been measured. This shows that atomic hydrogen is one of the main species in high density Ar-H₂O plasmas. The gas temperature does not exceed 550 K in the core of the plasma. To enable in situ calibration of the H TaLIF at atmospheric pressure a previously published O density calibration scheme is extended to include a correction for the line profiles by including overlap integrals as required by H TaLIF. The line width of H TaLIF, due to collision broadening has the same trend as the neutral density obtained by Rayleigh scattering. This suggests the possibility to use this technique to in situ probe neutral gas densities.

Authors:

Yatom, Shurik ^[1]; Luo, Yuchen ^[2]; Xiong, Qing ^[3]; Bruggeman, Peter J.  ^[2]

• Search DOE PAGES for author "Bruggeman, Peter J."
• Search DOE PAGES for ORCID "0000-0003-3346-7275"

---

+ Show Author Affiliations

1. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Univ. of Minnesota, Minneapolis, MN (United States)
2. Univ. of Minnesota, Minneapolis, MN (United States)
3. Univ. of Minnesota, Minneapolis, MN (United States); Chongqing Univ. (China)

Publication Date:

Thu Sep 21 00:00:00 EDT 2017

Research Org.:

Univ. of Minnesota, Minneapolis, MN (United States); Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Fusion Energy Sciences (FES); National Science Foundation (NSF)

OSTI Identifier:

1787620

Alternate Identifier(s):

OSTI ID: 1465667

Grant/Contract Number:  

SC0001939; PHY 1500135

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Physics. D, Applied Physics

Additional Journal Information:

Journal Volume: 50; Journal Issue: 41; Journal ID: ISSN 0022-3727

Publisher:

IOP Publishing

Country of Publication:

United States

Language:

English

Subject:

70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY