First simultaneous measurements of Reynolds stress with ball-pen and Langmuir probes

A new multi-pin probe head was installed and tested at the COMPASS tokamak. The probe head consists of several ball-pen and Langmuir probes in similar geometric configurations, which enables fast, simultaneous measurements of the radial and poloidal electric field components from differences of plas...

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Bibliographic Details
Published in:Review of scientific instruments 2017-06, Vol.88 (6), p.063501-063501
Main Authors: Grover, Ondrej, Adamek, Jiri, Seidl, Jakub, Devitre, Alexis, Sos, Miroslav, Vondracek, Petr, Bilkova, Petra, Hron, Martin
Format: Article
Language:English
Subjects:
Electric fields
Electron energy
Measurement methods
Reynolds stress
Scientific apparatus & instruments
Tokamak devices
Variation
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Summary:A new multi-pin probe head was installed and tested at the COMPASS tokamak. The probe head consists of several ball-pen and Langmuir probes in similar geometric configurations, which enables fast, simultaneous measurements of the radial and poloidal electric field components from differences of plasma or floating potentials using appropriately positioned ball-pen or Langmuir probes, respectively. The fast measurements of the radial electric field are compared with other methods of measuring selected frequency components of the radial electric field. The radial profiles of the Reynolds stress calculated from correlations of electric field fluctuations obtained by either probe type are compared along with their spectral composition. Lower Reynolds stress values are found for Langmuir probes in comparison to ball-pen probes due to negative contributions from higher frequency fluctuations possibly associated with electron temperature fluctuations.
ISSN:0034-6748
1089-7623
DOI:10.1063/1.4984240