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Title: Electron Bernstein wave electron temperature profile diagnostic

Abstract

Electron cyclotron emission (ECE) has been employed as a standard electron temperature profile diagnostic on many tokamaks and stellarators, but most magnetically confined plasma devices cannot take advantage of standard ECE diagnostics to measure temperature. They are either overdense, operating at high density relative to the magnetic field (e.g. where the plasma frequency is much greater than the electron cyclotron frequency, as in a spherical torus) or they have insufficient density and temperature to reach the blackbody condition. Electron Bernstein waves (EBWs) are electrostatic waves that can propagate in overdense plasmas and have a high optical thickness at the electron cyclotron resonance layers, as a result of their large perpendicular wavenumber. This paper reports on measurements of EBW emission on the CDX-U spherical torus, where B{sub o} {approximately} 2 kG, <n{sub e}> {approximately}10{sup 13} cm{sup {minus}3} and T{sub e} {approx} to 10 -- 200 eV. Results are presented for electromagnetic measurements of EBW emission, mode-converted near the plasma edge. The EBW emission was absolutely calibrated and compared to the electron temperature profile measured by a multi-point Thomson scattering diagnostic. Depending on the plasma conditions, the mode converted EBW radiation temperature was found to be less than or equal to T{submore » e} and the emission source was determined to be radially localized at the electron cyclotron resonance layer. A Langmuir triple probe and a 140 GHz interferometer were employed to measure changes in edge density profile in the vicinity of the upper hybrid resonance, where the mode conversion of the EBWs is expected to occur. Initial results suggest EBW emission and EBW heating are viable concepts for overdense plasmas.« less

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Princeton Plasma Physics Lab., NJ (US)
Sponsoring Org.:
USDOE Office of Energy Research (ER) (US)
OSTI Identifier:
758660
Report Number(s):
PPPL-3476
TRN: US0003976
DOE Contract Number:  
AC02-76CH03073
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 20 Jul 2000
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CDX-U SPHEROMAK; PLASMA DIAGNOSTICS; ELECTRON TEMPERATURE; PLASMA DENSITY; BERNSTEIN MODE; ELECTRON PLASMA WAVES; MODE CONVERSION

Citation Formats

Taylor, G, Efthimion, P, Jones, B, Munsat, T, Spaleta, J, Hosea, J, Kaita, R, Majeski, R, and Menard, J. Electron Bernstein wave electron temperature profile diagnostic. United States: N. p., 2000. Web. doi:10.2172/758660.
Taylor, G, Efthimion, P, Jones, B, Munsat, T, Spaleta, J, Hosea, J, Kaita, R, Majeski, R, & Menard, J. Electron Bernstein wave electron temperature profile diagnostic. United States. https://doi.org/10.2172/758660
Taylor, G, Efthimion, P, Jones, B, Munsat, T, Spaleta, J, Hosea, J, Kaita, R, Majeski, R, and Menard, J. Thu . "Electron Bernstein wave electron temperature profile diagnostic". United States. https://doi.org/10.2172/758660. https://www.osti.gov/servlets/purl/758660.
@article{osti_758660,
title = {Electron Bernstein wave electron temperature profile diagnostic},
author = {Taylor, G and Efthimion, P and Jones, B and Munsat, T and Spaleta, J and Hosea, J and Kaita, R and Majeski, R and Menard, J},
abstractNote = {Electron cyclotron emission (ECE) has been employed as a standard electron temperature profile diagnostic on many tokamaks and stellarators, but most magnetically confined plasma devices cannot take advantage of standard ECE diagnostics to measure temperature. They are either overdense, operating at high density relative to the magnetic field (e.g. where the plasma frequency is much greater than the electron cyclotron frequency, as in a spherical torus) or they have insufficient density and temperature to reach the blackbody condition. Electron Bernstein waves (EBWs) are electrostatic waves that can propagate in overdense plasmas and have a high optical thickness at the electron cyclotron resonance layers, as a result of their large perpendicular wavenumber. This paper reports on measurements of EBW emission on the CDX-U spherical torus, where B{sub o} {approximately} 2 kG, <n{sub e}> {approximately}10{sup 13} cm{sup {minus}3} and T{sub e} {approx} to 10 -- 200 eV. Results are presented for electromagnetic measurements of EBW emission, mode-converted near the plasma edge. The EBW emission was absolutely calibrated and compared to the electron temperature profile measured by a multi-point Thomson scattering diagnostic. Depending on the plasma conditions, the mode converted EBW radiation temperature was found to be less than or equal to T{sub e} and the emission source was determined to be radially localized at the electron cyclotron resonance layer. A Langmuir triple probe and a 140 GHz interferometer were employed to measure changes in edge density profile in the vicinity of the upper hybrid resonance, where the mode conversion of the EBWs is expected to occur. Initial results suggest EBW emission and EBW heating are viable concepts for overdense plasmas.},
doi = {10.2172/758660},
url = {https://www.osti.gov/biblio/758660}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2000},
month = {7}
}