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Title: Supersonic helium beam diagnostic for fluctuation measurements of electron temperature and density at the Tokamak TEXTOR

Abstract

A supersonic helium beam diagnostic, based on the line-ratio technique for high resolution electron density and temperature measurements in the plasma edge (r/a > 0.9) was designed, built, and optimised at TEXTOR (Torus Experiment for Technology Oriented Research). The supersonic injection system, based on the Campargue skimmer-nozzle concept, was developed and optimised in order to provide both a high neutral helium beam density of n{sub 0}= 1.5 Multiplication-Sign 10{sup 18} m{sup -3} and a low beam divergence of {+-}1 Degree-Sign simultaneously, achieving a poloidal resolution of {Delta}{sub poloidal}= 9 mm. The setup utilises a newly developed dead volume free piezo valve for operation in a high magnetic field environment of up to 2 T with a maximum repetition rate of 80 Hz. Gas injections are realised for a duration of 120 ms at a repetition rate of 2 Hz (duty cycle 1/3). In combination with a high sensitivity detection system, consisting of three 32 multi-channel photomultipliers (PMTs), measurements of edge electron temperature and density with a radial resolution of {Delta}{sub radial}= 2 mm and a maximum temporal resolution of {Delta}t Asymptotically-Equal-To 2 {mu}s (470 kHz) are possible for the first time. The diagnostic setup at TEXTOR is presented. The newlymore » developed injection system and its theoretical bases are discussed. The applicability of the stationary collisional-radiative model as basis of the line-ratio technique is shown. Finally, an example of a fluctuation analysis demonstrating the unique high temporal and spatial resolution capabilities of this new diagnostic is presented.« less

Authors:
; ; ; ;  [1]
  1. Institute of Energy and Climate Research, Plasma Physics, Forschungszentrum Juelich GmbH, Association EURATOM-FZJ, Partner in the Trilateral Euregio Cluster, Juelich (Germany)
Publication Date:
OSTI Identifier:
22093639
Resource Type:
Journal Article
Journal Name:
Review of Scientific Instruments
Additional Journal Information:
Journal Volume: 83; Journal Issue: 6; Other Information: (c) 2012 EURATOM; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0034-6748
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; BEAMS; CONFINEMENT; DENSITY; ELECTRON DENSITY; ELECTRON TEMPERATURE; FLUCTUATIONS; GAS INJECTION; HELIUM; ION TEMPERATURE; MAGNETIC FIELDS; NOZZLES; PHOTOMULTIPLIERS; PLASMA; PLASMA DENSITY; PLASMA DIAGNOSTICS; SENSITIVITY; SPATIAL RESOLUTION; SUPERSONIC FLOW; TEMPERATURE MEASUREMENT; TEXTOR TOKAMAK

Citation Formats

Kruezi, U., Stoschus, H., Schweer, B., Sergienko, G., and Samm, U. Supersonic helium beam diagnostic for fluctuation measurements of electron temperature and density at the Tokamak TEXTOR. United States: N. p., 2012. Web. doi:10.1063/1.4707150.
Kruezi, U., Stoschus, H., Schweer, B., Sergienko, G., & Samm, U. Supersonic helium beam diagnostic for fluctuation measurements of electron temperature and density at the Tokamak TEXTOR. United States. doi:10.1063/1.4707150.
Kruezi, U., Stoschus, H., Schweer, B., Sergienko, G., and Samm, U. Fri . "Supersonic helium beam diagnostic for fluctuation measurements of electron temperature and density at the Tokamak TEXTOR". United States. doi:10.1063/1.4707150.
@article{osti_22093639,
title = {Supersonic helium beam diagnostic for fluctuation measurements of electron temperature and density at the Tokamak TEXTOR},
author = {Kruezi, U. and Stoschus, H. and Schweer, B. and Sergienko, G. and Samm, U.},
abstractNote = {A supersonic helium beam diagnostic, based on the line-ratio technique for high resolution electron density and temperature measurements in the plasma edge (r/a > 0.9) was designed, built, and optimised at TEXTOR (Torus Experiment for Technology Oriented Research). The supersonic injection system, based on the Campargue skimmer-nozzle concept, was developed and optimised in order to provide both a high neutral helium beam density of n{sub 0}= 1.5 Multiplication-Sign 10{sup 18} m{sup -3} and a low beam divergence of {+-}1 Degree-Sign simultaneously, achieving a poloidal resolution of {Delta}{sub poloidal}= 9 mm. The setup utilises a newly developed dead volume free piezo valve for operation in a high magnetic field environment of up to 2 T with a maximum repetition rate of 80 Hz. Gas injections are realised for a duration of 120 ms at a repetition rate of 2 Hz (duty cycle 1/3). In combination with a high sensitivity detection system, consisting of three 32 multi-channel photomultipliers (PMTs), measurements of edge electron temperature and density with a radial resolution of {Delta}{sub radial}= 2 mm and a maximum temporal resolution of {Delta}t Asymptotically-Equal-To 2 {mu}s (470 kHz) are possible for the first time. The diagnostic setup at TEXTOR is presented. The newly developed injection system and its theoretical bases are discussed. The applicability of the stationary collisional-radiative model as basis of the line-ratio technique is shown. Finally, an example of a fluctuation analysis demonstrating the unique high temporal and spatial resolution capabilities of this new diagnostic is presented.},
doi = {10.1063/1.4707150},
journal = {Review of Scientific Instruments},
issn = {0034-6748},
number = 6,
volume = 83,
place = {United States},
year = {2012},
month = {6}
}