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Title: Comparison of spectroscopic and Thomson scattering measurements of electron densities and temperatures in a transient expanding plasma flow

Abstract

The expansion flow of helium plasma in the end loss region of a theta pinch has been studied. The accuracy of several spectroscopic techniques for determining plasma properties in the transient, inhomogeneous plasma has been evaluated. Plasma at a location of 2.5 cm outside the end of a 25- cm long theta-pinch coil is characterized by N/sub e/ approx.10/sup 16/ cm/sup -3/, T/sub e/ approx.6 eV. Radial electron density profiles were obtained by: (1) Abel inversion of plasma continuum emission from chords across the plasma column to produce relative radial electron density profiles, with normalization by a new technique, whereby a theoretical He II 4686-A spectral profile is calculated and compared to that observed experimentally being emitted across the diameter of the plasma column; and (2) direct prediction of an absolute electron density profile by Abel inversion of He II 4686-A spectral profiles obtained by viewing chords across the plasma column. Electron temperatures were obtained from spectroscopic measurements across the diameter of the plasma flow by: (1) measurement of the ratio of the He II 4686-A line intensity to the underlying continuum intensity; and (2) measurement of the absolute intensity of the He II 4686-A line. The accuracy of thesemore » spectroscopic techniques in a pulsed discharge, with plasma undergoing flow expansion, will be indicated by comparison of the results with those from Thomson scattering.« less

Authors:
; ; ;
Publication Date:
Research Org.:
The Pennsylvania State University, University Park, Pennsylvania 16802
OSTI Identifier:
5258899
DOE Contract Number:  
AC02-76ET53018
Resource Type:
Journal Article
Journal Name:
J. Appl. Phys.; (United States)
Additional Journal Information:
Journal Volume: 53:6
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; THETA PINCH; ELECTRON DENSITY; ELECTRON TEMPERATURE; PLASMA EXPANSION; COMPARATIVE EVALUATIONS; ELECTRIC DISCHARGES; EXPERIMENTAL DATA; HELIUM; HELIUM IONS; PULSES; SPATIAL DISTRIBUTION; SPECTROSCOPY; THOMSON SCATTERING; TRANSIENTS; CHARGED PARTICLES; DATA; DISTRIBUTION; ELEMENTS; EXPANSION; FLUIDS; GASES; INELASTIC SCATTERING; INFORMATION; IONS; NONMETALS; NUMERICAL DATA; PINCH EFFECT; RARE GASES; SCATTERING; 700102* - Fusion Energy- Plasma Research- Diagnostics

Citation Formats

Heidrich, J E, Jacoby, B A, York, T M, and Robinson, J W. Comparison of spectroscopic and Thomson scattering measurements of electron densities and temperatures in a transient expanding plasma flow. United States: N. p., 1982. Web. doi:10.1063/1.331235.
Heidrich, J E, Jacoby, B A, York, T M, & Robinson, J W. Comparison of spectroscopic and Thomson scattering measurements of electron densities and temperatures in a transient expanding plasma flow. United States. https://doi.org/10.1063/1.331235
Heidrich, J E, Jacoby, B A, York, T M, and Robinson, J W. 1982. "Comparison of spectroscopic and Thomson scattering measurements of electron densities and temperatures in a transient expanding plasma flow". United States. https://doi.org/10.1063/1.331235.
@article{osti_5258899,
title = {Comparison of spectroscopic and Thomson scattering measurements of electron densities and temperatures in a transient expanding plasma flow},
author = {Heidrich, J E and Jacoby, B A and York, T M and Robinson, J W},
abstractNote = {The expansion flow of helium plasma in the end loss region of a theta pinch has been studied. The accuracy of several spectroscopic techniques for determining plasma properties in the transient, inhomogeneous plasma has been evaluated. Plasma at a location of 2.5 cm outside the end of a 25- cm long theta-pinch coil is characterized by N/sub e/ approx.10/sup 16/ cm/sup -3/, T/sub e/ approx.6 eV. Radial electron density profiles were obtained by: (1) Abel inversion of plasma continuum emission from chords across the plasma column to produce relative radial electron density profiles, with normalization by a new technique, whereby a theoretical He II 4686-A spectral profile is calculated and compared to that observed experimentally being emitted across the diameter of the plasma column; and (2) direct prediction of an absolute electron density profile by Abel inversion of He II 4686-A spectral profiles obtained by viewing chords across the plasma column. Electron temperatures were obtained from spectroscopic measurements across the diameter of the plasma flow by: (1) measurement of the ratio of the He II 4686-A line intensity to the underlying continuum intensity; and (2) measurement of the absolute intensity of the He II 4686-A line. The accuracy of these spectroscopic techniques in a pulsed discharge, with plasma undergoing flow expansion, will be indicated by comparison of the results with those from Thomson scattering.},
doi = {10.1063/1.331235},
url = {https://www.osti.gov/biblio/5258899}, journal = {J. Appl. Phys.; (United States)},
number = ,
volume = 53:6,
place = {United States},
year = {1982},
month = {6}
}