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Improved spatial calibration for the CXRS system on EAST.
1School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230026, China.
The Review of Scientific Instruments
|December 3, 2016
Summary
Accurate measurements of ion temperature and rotation on EAST were achieved using Charge eXchange Recombination Spectroscopy (CXRS). Improved spatial calibration techniques, accounting for vacuum pressure changes, ensure precise data for fusion energy research.
Area of Science:
- Plasma Physics
- Fusion Energy Research
- Spectroscopy
Background:
- The EAST tokamak utilizes Charge eXchange Recombination Spectroscopy (CXRS) for plasma diagnostics.
- Accurate spatial calibration is crucial for reliable ion temperature and rotation measurements.
Purpose of the Study:
- To enhance the spatial calibration of the EAST CXRS diagnostic system.
- To provide a complete and accurate description of the EAST CXRS system's calibration.
Main Methods:
- Utilized an articulated flexible coordinate measuring arm for initial sightline location.
- Assessed vacuum pressure effects on sightline position using an articulated inspection arm and back-illuminated sightlines.
- Determined periscope rotation via Doppler shift of neutral beam emission spectra (without magnetic field).
- Validated calibration using Zeeman splitting of neutral beam emission spectra (with magnetic field).
Main Results:
- Developed and implemented improved spatial calibration techniques for the CXRS diagnostic.
- Quantified periscope rotation (∼0.4°) due to air pressure changes post-vacuum pumping.
- Observed a consequent shift in major radius observation positions (∼20 mm) towards the lower field side.
- Demonstrated agreement between calibration results and Zeeman splitting measurements.
Conclusions:
- The implemented spatial calibration techniques provide accurate ion temperature and rotation profiles on EAST.
- Understanding and correcting for vacuum-induced periscope rotation is essential for diagnostic precision.
- The refined CXRS calibration enhances the reliability of plasma confinement studies on EAST.
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