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Title: Two-dimensional numerical study of two counter-propagating helium plasma jets in air at atmospheric pressure

Abstract

In this paper, a computational study of two counter-propagating helium plasma jets in ambient air is presented. A two-dimensional fluid model is applied to investigate the physical processes of the two plasma jets interaction (PJI) driven by equal and unequal voltages, respectively. In all studied cases, the PJI results in a decrease of both plasma bullets propagation velocity. When the two plasma jets are driven by equal voltages, they never merge but rather approach each other around the middle of the gas gap at a minimum approach distance, and the minimal distance decreases with the increase of both the applied voltages and initial electron density, but increases with the increase of the relative permittivity. When the two plasma jets are driven by unequal voltages, we observe the two plasma jets will merge at the position away from the middle of the gas gap. The effect of applied voltage difference on the PJI is also studied.

Authors:
; ;  [1];  [2]
  1. Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)
  2. College of Physics Science and Technology, Hebei University, Baoding 071002 (China)
Publication Date:
OSTI Identifier:
22304162
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 6; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; AIR; ATMOSPHERIC PRESSURE; DISTANCE; ELECTRIC POTENTIAL; ELECTRON DENSITY; HELIUM; NUMERICAL ANALYSIS; PERMITTIVITY; PLASMA JETS; TWO-DIMENSIONAL CALCULATIONS; VELOCITY

Citation Formats

Yan, Wen, Sang, Chaofeng, Wang, Dezhen, E-mail: wangdez@dlut.edu.cn, and Liu, Fucheng. Two-dimensional numerical study of two counter-propagating helium plasma jets in air at atmospheric pressure. United States: N. p., 2014. Web. doi:10.1063/1.4882440.
Yan, Wen, Sang, Chaofeng, Wang, Dezhen, E-mail: wangdez@dlut.edu.cn, & Liu, Fucheng. Two-dimensional numerical study of two counter-propagating helium plasma jets in air at atmospheric pressure. United States. doi:10.1063/1.4882440.
Yan, Wen, Sang, Chaofeng, Wang, Dezhen, E-mail: wangdez@dlut.edu.cn, and Liu, Fucheng. Sun . "Two-dimensional numerical study of two counter-propagating helium plasma jets in air at atmospheric pressure". United States. doi:10.1063/1.4882440.
@article{osti_22304162,
title = {Two-dimensional numerical study of two counter-propagating helium plasma jets in air at atmospheric pressure},
author = {Yan, Wen and Sang, Chaofeng and Wang, Dezhen, E-mail: wangdez@dlut.edu.cn and Liu, Fucheng},
abstractNote = {In this paper, a computational study of two counter-propagating helium plasma jets in ambient air is presented. A two-dimensional fluid model is applied to investigate the physical processes of the two plasma jets interaction (PJI) driven by equal and unequal voltages, respectively. In all studied cases, the PJI results in a decrease of both plasma bullets propagation velocity. When the two plasma jets are driven by equal voltages, they never merge but rather approach each other around the middle of the gas gap at a minimum approach distance, and the minimal distance decreases with the increase of both the applied voltages and initial electron density, but increases with the increase of the relative permittivity. When the two plasma jets are driven by unequal voltages, we observe the two plasma jets will merge at the position away from the middle of the gas gap. The effect of applied voltage difference on the PJI is also studied.},
doi = {10.1063/1.4882440},
journal = {Physics of Plasmas},
number = 6,
volume = 21,
place = {United States},
year = {Sun Jun 15 00:00:00 EDT 2014},
month = {Sun Jun 15 00:00:00 EDT 2014}
}
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  • Atmospheric pressure plasma jets (APPJs) are being investigated in the context plasma medicine and biotechnology applications, and surface functionalization. The composition of the surface being treated ranges from plastics, liquids, and biological tissue, to metals. The dielectric constant of these materials ranges from as low as 1.5 for plastics to near 80 for liquids, and essentially infinite for metals. The electrical properties of the surface are not independent variables as the permittivity of the material being treated has an effect on the dynamics of the incident APPJ. In this paper, results are discussed from a computational investigation of the interactionmore » of an APPJ incident onto materials of varying permittivity, and their impact on the discharge dynamics of the plasma jet. The computer model used in this investigation solves Poisson's equation, transport equations for charged and neutral species, the electron energy equation, and the Navier-Stokes equations for the neutral gas flow. The APPJ is sustained in He/O{sub 2} = 99.8/0.2 flowing into humid air, and is directed onto dielectric surfaces in contact with ground with dielectric constants ranging from 2 to 80, and a grounded metal surface. Low values of relative permittivity encourage propagation of the electric field into the treated material and formation and propagation of a surface ionization wave. High values of relative permittivity promote the restrike of the ionization wave and the formation of a conduction channel between the plasma discharge and the treated surface. The distribution of space charge surrounding the APPJ is discussed.« less
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