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Title: The ion polytropic coefficient in a collisionless sheath containing hot ions

Abstract

The fluid approach has been widely used to study plasma sheath dynamics. For a sheath containing hot ions whose temperature is greater than the electron's, how to truncate the fluid hierarchy chain equations while retaining to the fullest extent of the kinetic effects is always a difficult problem. In this paper, a one-dimensional, collisionless sheath containing hot ions is studied via particle-in-cell simulations. By analyzing the ion energy equation and taking the kinetic effects into account, we have shown that the ion polytropic coefficient in the vicinity of the sheath edge is approximately constant so that the state equation with the modified polytropic coefficient can be used to close the hierarchy chain of the ion fluid equations. The value of the polytropic coefficient strongly depends on the hot ion temperature and its concentration in the plasma. The semi-analytical model is given to interpret the simulation results. As an application, the kinetic effects on the ion saturation current density in the probe theory are discussed.

Authors:
; ;  [1];  [2]
  1. Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)
  2. (China)
Publication Date:
OSTI Identifier:
22599952
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 23; Journal Issue: 8; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COMPUTERIZED SIMULATION; CONCENTRATION RATIO; CURRENT DENSITY; ELECTRONS; EQUATIONS; FLUIDS; ION TEMPERATURE; IONS; ONE-DIMENSIONAL CALCULATIONS; PLASMA SHEATH

Citation Formats

Lin, Binbin, Xiang, Nong, E-mail: xiangn@ipp.ac.cn, Ou, Jing, and Center for Magnetic Fusion Theory, Chinese Academy of Sciences, Hefei 230031. The ion polytropic coefficient in a collisionless sheath containing hot ions. United States: N. p., 2016. Web. doi:10.1063/1.4960558.
Lin, Binbin, Xiang, Nong, E-mail: xiangn@ipp.ac.cn, Ou, Jing, & Center for Magnetic Fusion Theory, Chinese Academy of Sciences, Hefei 230031. The ion polytropic coefficient in a collisionless sheath containing hot ions. United States. doi:10.1063/1.4960558.
Lin, Binbin, Xiang, Nong, E-mail: xiangn@ipp.ac.cn, Ou, Jing, and Center for Magnetic Fusion Theory, Chinese Academy of Sciences, Hefei 230031. Mon . "The ion polytropic coefficient in a collisionless sheath containing hot ions". United States. doi:10.1063/1.4960558.
@article{osti_22599952,
title = {The ion polytropic coefficient in a collisionless sheath containing hot ions},
author = {Lin, Binbin and Xiang, Nong, E-mail: xiangn@ipp.ac.cn and Ou, Jing and Center for Magnetic Fusion Theory, Chinese Academy of Sciences, Hefei 230031},
abstractNote = {The fluid approach has been widely used to study plasma sheath dynamics. For a sheath containing hot ions whose temperature is greater than the electron's, how to truncate the fluid hierarchy chain equations while retaining to the fullest extent of the kinetic effects is always a difficult problem. In this paper, a one-dimensional, collisionless sheath containing hot ions is studied via particle-in-cell simulations. By analyzing the ion energy equation and taking the kinetic effects into account, we have shown that the ion polytropic coefficient in the vicinity of the sheath edge is approximately constant so that the state equation with the modified polytropic coefficient can be used to close the hierarchy chain of the ion fluid equations. The value of the polytropic coefficient strongly depends on the hot ion temperature and its concentration in the plasma. The semi-analytical model is given to interpret the simulation results. As an application, the kinetic effects on the ion saturation current density in the probe theory are discussed.},
doi = {10.1063/1.4960558},
journal = {Physics of Plasmas},
number = 8,
volume = 23,
place = {United States},
year = {Mon Aug 15 00:00:00 EDT 2016},
month = {Mon Aug 15 00:00:00 EDT 2016}
}