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Title: Mach probe interpretation in the presence of suprathermal electrons

Abstract

The collisionless theory of Mach probes assuming isothermal, Maxwellian electrons is extended to include an isotropic, two-temperature electron distribution function. The kinetic equations for ion and electron motion in the probe wake are solved using a quasineutral particle-in-cell method, which compares qualitatively well with the results of a simple fluid model. The measured Mach number decreases slightly with increasing hot electron concentration, but the main effect is on the measured electron temperature. Due to the fact that the probe is sensitive to even a tiny population of hot electrons, the resulting ion sound speed can be overestimated by up to a factor of 2, leading to measurements of absolute flow speed that are too large.

Authors:
;  [1];  [2]
  1. Centre de Cadarache, Association EURATOM-CEA, CEA/DSM/DRFC, 13108 Saint Paul Lez Durance (France)
  2. (Czech Republic)
Publication Date:
OSTI Identifier:
20974881
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 3; Other Information: DOI: 10.1063/1.2672896; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; AUGMENTATION; DISTRIBUTION FUNCTIONS; ELECTRON TEMPERATURE; ELECTRONS; ION TEMPERATURE; IONS; KINETIC EQUATIONS; MACH NUMBER; PLASMA; PLASMA SIMULATION; PROBES; SOUND WAVES

Citation Formats

Gunn, J. P., Fuchs, V., and Association EURATOM/IPP.CR, Za Slovankou 3, 18200 Prague 8. Mach probe interpretation in the presence of suprathermal electrons. United States: N. p., 2007. Web. doi:10.1063/1.2672896.
Gunn, J. P., Fuchs, V., & Association EURATOM/IPP.CR, Za Slovankou 3, 18200 Prague 8. Mach probe interpretation in the presence of suprathermal electrons. United States. doi:10.1063/1.2672896.
Gunn, J. P., Fuchs, V., and Association EURATOM/IPP.CR, Za Slovankou 3, 18200 Prague 8. Thu . "Mach probe interpretation in the presence of suprathermal electrons". United States. doi:10.1063/1.2672896.
@article{osti_20974881,
title = {Mach probe interpretation in the presence of suprathermal electrons},
author = {Gunn, J. P. and Fuchs, V. and Association EURATOM/IPP.CR, Za Slovankou 3, 18200 Prague 8},
abstractNote = {The collisionless theory of Mach probes assuming isothermal, Maxwellian electrons is extended to include an isotropic, two-temperature electron distribution function. The kinetic equations for ion and electron motion in the probe wake are solved using a quasineutral particle-in-cell method, which compares qualitatively well with the results of a simple fluid model. The measured Mach number decreases slightly with increasing hot electron concentration, but the main effect is on the measured electron temperature. Due to the fact that the probe is sensitive to even a tiny population of hot electrons, the resulting ion sound speed can be overestimated by up to a factor of 2, leading to measurements of absolute flow speed that are too large.},
doi = {10.1063/1.2672896},
journal = {Physics of Plasmas},
number = 3,
volume = 14,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}