Journal article · Conference paper
Collective Thomson Scattering Diagnostic for Wendelstein 7-X at 175 GHz
Max Planck Institute for Plasma Physics1
Plasma Physics and Fusion Energy, Department of Physics, Technical University of Denmark2
Department of Physics, Technical University of Denmark3
Karlsruhe Institute of Technology4
University of Stuttgart5
National Institutes of Natural Sciences - National Institute for Fusion Science6
The Collective Thomson Scattering (CTS) diagnostic measures the scattering spectrum of incident radiation off collective fluctuations in plasmas. In Wendelstein 7-X (W7-X) the diagnostic uses a 140 GHz heating gyrotron as a source of the probing radiation. At this frequency, the CTS spectra are heavily affected by the electron cyclotron emission, and the microwave beam propagation is restricted at typical W7-X plasma parameters.
The diagnostic was successfully commissioned in the last experimental campaign and demonstrated ion temperature measurements. However, the signal-to-noise ratio was too low for measuring other quantities such as the fast-ion velocity distribution function or the fuel ion ratio. Currently, the W7-X CTS diagnostic is undergoing an upgrade to a frequency of 175 GHz.
This will increase the sensitivity of the diagnostic, since the noise due to electron cyclotron emission will be reduced, and it will relax the constraints on microwave beam propagation in W7-X. Here we present the salient features of the upgraded CTS system and discuss its prospects for both thermal-ion and fast-ion measurements.
Language: | English |
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Year: | 2020 |
Pages: | C05035-C05035 |
Proceedings: | 19th International Symposium on Laser-Aided Plasma Diagnostics |
ISSN: | 17480221 |
Types: | Journal article and Conference paper |
DOI: | 10.1088/1748-0221/15/05/C05035 |
ORCIDs: | Nielsen, S. K. , Korsholm, S.B. , Salewski, M. , Rasmussen, J. and Tancetti, A. |