Localized measurement of short wavelength plasma fluctuations with the DIII-D phase contrast imaging diagnostic
A novel rotating mask system has been designed and implemented on the DIII-D phase contrast imaging (PCI) diagnostic to produce the first spatially localized PCI measurements of a tokamak plasma. The localization technique makes use of the variation in the magnetic field component perpendicular to t...
| Main Authors: | , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
American Institute of Physics
2010
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| Online Access: | http://hdl.handle.net/1721.1/51858 https://orcid.org/0000-0002-9518-4097 |
| Summary: | A novel rotating mask system has been designed and implemented on the DIII-D phase contrast imaging (PCI) diagnostic to produce the first spatially localized PCI measurements of a tokamak plasma. The localization technique makes use of the variation in the magnetic field component perpendicular to the viewing chord as a function of chord height. This new capability provides measurements in the range of 2<k<30 cm[superscript −1], 10 kHz<f<10 MHz, and 0.7<r/a<1. This technique provides a spatial resolution of 10 cm at k=15 cm[superscript −1] and can realistically provide measurements at a rate of 10 profiles/s. Calibration measurements show accurate characterization of the system transfer function making feasible a time dependent analysis that results in improved localization. Initial measurements show turbulence to peak near the plasma edge. This upgrade is part of a broader program to operate the DIII-D PCI at wave numbers up to 40 cm[superscript −1] to probe electron scale turbulence in the plasma core. |
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