skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Electron temperature measurement in Maxwellian non-isothermal beam plasma of an ion thruster

Abstract

Published electron temperature profiles of the beam plasma from ion thrusters reveal many divergences both in magnitude and radial variation. In order to know exactly the radial distributions of electron temperature and understand the beam plasma characteristics, we applied five different experimental approaches to measure the spatial profiles of electron temperature and compared the agreement and disagreement of the electron temperature profiles obtained from these techniques. Experimental results show that the triple Langmuir probe and adiabatic poly-tropic law methods could provide more accurate space-resolved electron temperature of the beam plasma than other techniques. Radial electron temperature profiles indicate that the electrons in the beam plasma are non-isothermal, which is supported by a radial decrease (∼2 eV) of electron temperature as the plume plasma expands outward. Therefore, the adiabatic “poly-tropic law” is more appropriate than the isothermal “barometric law” to be used in electron temperature calculations. Moreover, the calculation results show that the electron temperature profiles derived from the “poly-tropic law” are in better agreement with the experimental data when the specific heat ratio (γ) lies in the range of 1.2-1.4 instead of 5/3.

Authors:
; ; ; ;  [1]
  1. School of Astronautics, Beihang University, Beijing 100191 (China)
Publication Date:
OSTI Identifier:
22392362
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 86; Journal Issue: 2; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; BEAMS; ELECTRON TEMPERATURE; ION THRUSTERS; LANGMUIR PROBE; PLASMA; SPATIAL DISTRIBUTION; SPECIFIC HEAT

Citation Formats

Zhang, Zun, Tang, Haibin, E-mail: thb@buaa.edu.cn, Kong, Mengdi, Zhang, Zhe, and Ren, Junxue. Electron temperature measurement in Maxwellian non-isothermal beam plasma of an ion thruster. United States: N. p., 2015. Web. doi:10.1063/1.4907962.
Zhang, Zun, Tang, Haibin, E-mail: thb@buaa.edu.cn, Kong, Mengdi, Zhang, Zhe, & Ren, Junxue. Electron temperature measurement in Maxwellian non-isothermal beam plasma of an ion thruster. United States. doi:10.1063/1.4907962.
Zhang, Zun, Tang, Haibin, E-mail: thb@buaa.edu.cn, Kong, Mengdi, Zhang, Zhe, and Ren, Junxue. Sun . "Electron temperature measurement in Maxwellian non-isothermal beam plasma of an ion thruster". United States. doi:10.1063/1.4907962.
@article{osti_22392362,
title = {Electron temperature measurement in Maxwellian non-isothermal beam plasma of an ion thruster},
author = {Zhang, Zun and Tang, Haibin, E-mail: thb@buaa.edu.cn and Kong, Mengdi and Zhang, Zhe and Ren, Junxue},
abstractNote = {Published electron temperature profiles of the beam plasma from ion thrusters reveal many divergences both in magnitude and radial variation. In order to know exactly the radial distributions of electron temperature and understand the beam plasma characteristics, we applied five different experimental approaches to measure the spatial profiles of electron temperature and compared the agreement and disagreement of the electron temperature profiles obtained from these techniques. Experimental results show that the triple Langmuir probe and adiabatic poly-tropic law methods could provide more accurate space-resolved electron temperature of the beam plasma than other techniques. Radial electron temperature profiles indicate that the electrons in the beam plasma are non-isothermal, which is supported by a radial decrease (∼2 eV) of electron temperature as the plume plasma expands outward. Therefore, the adiabatic “poly-tropic law” is more appropriate than the isothermal “barometric law” to be used in electron temperature calculations. Moreover, the calculation results show that the electron temperature profiles derived from the “poly-tropic law” are in better agreement with the experimental data when the specific heat ratio (γ) lies in the range of 1.2-1.4 instead of 5/3.},
doi = {10.1063/1.4907962},
journal = {Review of Scientific Instruments},
number = 2,
volume = 86,
place = {United States},
year = {Sun Feb 15 00:00:00 EST 2015},
month = {Sun Feb 15 00:00:00 EST 2015}
}
  • Calculations are reported which demonstrate the importance of taking into account the deviation from a Maxwellian electron distribution in impurity diagnostics in tokamaks. At the field levels in existing tokamaks, the ion charge distribution shifts toward higher charges. A different ion may become the ''most representative'' ion.
  • Solitons (small-amplitude long-lived waves) collision and rogue waves (large-amplitude short-lived waves) in non-Maxwellian electron-positron-ion plasma have been investigated. For the solitons collision, the extended Poincaré-Lighthill-Kuo perturbation method is used to derive the coupled Korteweg-de Vries (KdV) equations with the quadratic nonlinearities and their corresponding phase shifts. The calculations reveal that both positive and negative polarity solitons can propagate in the present model. At critical value of plasma parameters, the coefficients of the quadratic nonlinearities disappear. Therefore, the coupled modified KdV (mKdV) equations with cubic nonlinearities and their corresponding phase shifts have been derived. The effects of the electron-to-positron temperature ratio,more » the ion-to-electron temperature ratio, the positron-to-ion concentration, and the nonextensive parameter on the colliding solitons profiles and their corresponding phase shifts are examined. Moreover, generation of ion-acoustic rogue waves from small-amplitude initial perturbations in plasmas is studied in the framework of the mKdV equation. The properties of the ion-acoustic rogue waves are examined within a nonlinear Schrödinger equation (NLSE) that has been derived from the mKdV equation. The dependence of the rogue wave profile on the relevant physical parameters has been investigated. Furthermore, it is found that the NLSE that has been derived from the KdV equation cannot support the propagation of rogue waves.« less
  • We describe a technique for producing a Maxwell-Boltzmann electron energy distribution using an electron beam ion trap (EBIT). The technique was implemented on the Lawrence Livermore EBIT to simulate Maxwellian plasmas. We discuss technical and experimental issues related to these simulations. To verify the fidelity of the quasi-Maxwellian, we have measured line emission due to dielectronic recombination (DR) and electron impact excitation (EIE) of heliumlike neon, magnesium, and argon for a range of simulated electron temperatures. The ratio of DR to EIE lines in heliumlike ions is a well understood electron temperature diagnostic. The spectroscopically inferred quasi-Maxwellian temperatures are inmore » excellent agreement with the simulated temperatures. (c) 2000 American Institute of Physics.« less