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Title: Diagnosing pure-electron plasmas with internal particle flux probes

Abstract

Techniques for measuring local plasma potential, density, and temperature of pure-electron plasmas using emissive and Langmuir probes are described. The plasma potential is measured as the least negative potential at which a hot tungsten filament emits electrons. Temperature is measured, as is commonly done in quasineutral plasmas, through the interpretation of a Langmuir probe current-voltage characteristic. Due to the lack of ion-saturation current, the density must also be measured through the interpretation of this characteristic thereby greatly complicating the measurement. Measurements are further complicated by low densities, low cross field transport rates, and large flows typical of pure-electron plasmas. This article describes the use of these techniques on pure-electron plasmas in the Columbia Non-neutral Torus (CNT) stellarator. Measured values for present baseline experimental parameters in CNT are {phi}{sub p}=-200{+-}2 V, T{sub e}=4{+-}1 eV, and n{sub e} on the order of 10{sup 12} m{sup -3} in the interior.

Authors:
; ; ; ;  [1]
  1. Applied Physics and Applied Mathematics Department, Columbia University, New York, New York 10027 (United States)
Publication Date:
OSTI Identifier:
20953238
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 78; Journal Issue: 1; Other Information: DOI: 10.1063/1.2431084; (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; ELECTRON TEMPERATURE; ELECTRONS; ION TEMPERATURE; LANGMUIR PROBE; PLASMA; PLASMA CONFINEMENT; PLASMA DENSITY; PLASMA POTENTIAL; STELLARATORS; TUNGSTEN

Citation Formats

Kremer, J. P., Pedersen, T. Sunn, Marksteiner, Q., Lefrancois, R. G., and Hahn, M. Diagnosing pure-electron plasmas with internal particle flux probes. United States: N. p., 2007. Web. doi:10.1063/1.2431084.
Kremer, J. P., Pedersen, T. Sunn, Marksteiner, Q., Lefrancois, R. G., & Hahn, M. Diagnosing pure-electron plasmas with internal particle flux probes. United States. doi:10.1063/1.2431084.
Kremer, J. P., Pedersen, T. Sunn, Marksteiner, Q., Lefrancois, R. G., and Hahn, M. Mon . "Diagnosing pure-electron plasmas with internal particle flux probes". United States. doi:10.1063/1.2431084.
@article{osti_20953238,
title = {Diagnosing pure-electron plasmas with internal particle flux probes},
author = {Kremer, J. P. and Pedersen, T. Sunn and Marksteiner, Q. and Lefrancois, R. G. and Hahn, M.},
abstractNote = {Techniques for measuring local plasma potential, density, and temperature of pure-electron plasmas using emissive and Langmuir probes are described. The plasma potential is measured as the least negative potential at which a hot tungsten filament emits electrons. Temperature is measured, as is commonly done in quasineutral plasmas, through the interpretation of a Langmuir probe current-voltage characteristic. Due to the lack of ion-saturation current, the density must also be measured through the interpretation of this characteristic thereby greatly complicating the measurement. Measurements are further complicated by low densities, low cross field transport rates, and large flows typical of pure-electron plasmas. This article describes the use of these techniques on pure-electron plasmas in the Columbia Non-neutral Torus (CNT) stellarator. Measured values for present baseline experimental parameters in CNT are {phi}{sub p}=-200{+-}2 V, T{sub e}=4{+-}1 eV, and n{sub e} on the order of 10{sup 12} m{sup -3} in the interior.},
doi = {10.1063/1.2431084},
journal = {Review of Scientific Instruments},
number = 1,
volume = 78,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}