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Title: Helium line ratio spectroscopy for high spatiotemporal resolution plasma edge profile measurements at ASDEX Upgrade (invited)

Abstract

The thermal helium beam edge diagnostic has recently been upgraded at the ASDEX Upgrade (AUG) tokamak experiment. Line ratio spectroscopy on neutral helium is a valuable tool for simultaneous determination of the electron temperature and density of plasmas. The diagnostic now offers a temporal resolution of 900 kHz with a spatial resolution of up to 3 mm at 32 lines of sight (LOS) simultaneously. The LOS covers a radial region of 8.5 cm, starting at the limiter radius and reaching into the confined region beyond the separatrix. Two components are of particular importance for the aforementioned hardware improvements. The first is the optical head, which collects the light from the experiment. Equipped with an innovative clamping system for optical fiber ends, an arbitrary distribution pattern of LOS can be achieved to gain radial and poloidal profiles. The second major development is a new polychromator system that measures the intensity of the 587 nm, 667 nm, 706 nm, and 728 nm helium lines simultaneously for 32 channels with filter-photomultiplier tube arrays. Thus, the thermal helium beam diagnostic supplements the AUG edge diagnostics, offering fast and spatially highly resolved electron temperature and density profile measurements that cover the plasma edge and scrape-offmore » layer region. Plasma fluctuations, edge localized modes, filaments, and other turbulent structures are resolved, allowing analysis of their frequency and localization or their propagation velocity.« less

Authors:
ORCiD logo [1];  [2];  [2];  [2];  [2];  [2]; ORCiD logo [3]; ORCiD logo [4];  [1]
  1. Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching, Germany; Physik Department E28, Technische Universität München, 85748 Garching, Germany
  2. Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching, Germany
  3. Astro Fusion Spectre, LLC, 11263 Avenida de los Lobos, Unit D, San Diego, California 92127, USA
  4. Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
Publication Date:
Research Org.:
Univ. of Wisconsin, Madison, WI (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
Contributing Org.:
ASDEX Upgrade Team
OSTI Identifier:
1612110
Alternate Identifier(s):
OSTI ID: 1460030
Grant/Contract Number:  
SC0014210; SC00013911
Resource Type:
Accepted Manuscript
Journal Name:
Review of Scientific Instruments
Additional Journal Information:
Journal Volume: 89; Journal Issue: 10; Journal ID: ISSN 0034-6748
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION; Instruments & Instrumentation; Physics; Plasma diagnostics Polychromator; Optical fibers; Photomultipliers; Helium Electron density; Lenses; Spectroscopy; Plasma fluctuations; Geometrical optics

Citation Formats

Griener, M., Wolfrum, E., Cavedon, M., Dux, R., Rohde, V., Sochor, M., Muñoz Burgos, J. M., Schmitz, O., and Stroth, U. Helium line ratio spectroscopy for high spatiotemporal resolution plasma edge profile measurements at ASDEX Upgrade (invited). United States: N. p., 2018. Web. doi:10.1063/1.5034446.
Griener, M., Wolfrum, E., Cavedon, M., Dux, R., Rohde, V., Sochor, M., Muñoz Burgos, J. M., Schmitz, O., & Stroth, U. Helium line ratio spectroscopy for high spatiotemporal resolution plasma edge profile measurements at ASDEX Upgrade (invited). United States. doi:10.1063/1.5034446.
Griener, M., Wolfrum, E., Cavedon, M., Dux, R., Rohde, V., Sochor, M., Muñoz Burgos, J. M., Schmitz, O., and Stroth, U. Mon . "Helium line ratio spectroscopy for high spatiotemporal resolution plasma edge profile measurements at ASDEX Upgrade (invited)". United States. doi:10.1063/1.5034446. https://www.osti.gov/servlets/purl/1612110.
@article{osti_1612110,
title = {Helium line ratio spectroscopy for high spatiotemporal resolution plasma edge profile measurements at ASDEX Upgrade (invited)},
author = {Griener, M. and Wolfrum, E. and Cavedon, M. and Dux, R. and Rohde, V. and Sochor, M. and Muñoz Burgos, J. M. and Schmitz, O. and Stroth, U.},
abstractNote = {The thermal helium beam edge diagnostic has recently been upgraded at the ASDEX Upgrade (AUG) tokamak experiment. Line ratio spectroscopy on neutral helium is a valuable tool for simultaneous determination of the electron temperature and density of plasmas. The diagnostic now offers a temporal resolution of 900 kHz with a spatial resolution of up to 3 mm at 32 lines of sight (LOS) simultaneously. The LOS covers a radial region of 8.5 cm, starting at the limiter radius and reaching into the confined region beyond the separatrix. Two components are of particular importance for the aforementioned hardware improvements. The first is the optical head, which collects the light from the experiment. Equipped with an innovative clamping system for optical fiber ends, an arbitrary distribution pattern of LOS can be achieved to gain radial and poloidal profiles. The second major development is a new polychromator system that measures the intensity of the 587 nm, 667 nm, 706 nm, and 728 nm helium lines simultaneously for 32 channels with filter-photomultiplier tube arrays. Thus, the thermal helium beam diagnostic supplements the AUG edge diagnostics, offering fast and spatially highly resolved electron temperature and density profile measurements that cover the plasma edge and scrape-off layer region. Plasma fluctuations, edge localized modes, filaments, and other turbulent structures are resolved, allowing analysis of their frequency and localization or their propagation velocity.},
doi = {10.1063/1.5034446},
journal = {Review of Scientific Instruments},
number = 10,
volume = 89,
place = {United States},
year = {2018},
month = {10}
}

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