Development of an 11-channel multi wavelength imaging diagnostic for divertor plasmas in MAST Upgrade

Feng, X.; Calcines, A.; Sharples, R.M.; Lipschultz, B.; Perek, A.; Vijvers, W.A.J.; Harrison, J.R.; Allcock, J.S.; Andrebe, Y.; Duval, B.P.; Mumgaard, R.T.

Abstract

Divertor detachment and alternative divertor magnetic geometries are predicted to be promising approaches to handle the power exhaust of future fusion devices. In order to understand the detachment process caused by volumetric losses in alternative divertor magnetic geometries, a Multi-Wavelength Imaging (MWI) diagnostic has recently been designed and built for the Mega Amp Spherical Tokamak Upgrade. The MWI diagnostic will simultaneously capture 11 spectrally filtered images of the visible light emitted from divertor plasmas and provide crucial knowledge for the interpretation of observations and modeling efforts. This paper presents the optical design, mechanical design, hardware, and test results of an 11-channel MWI system with a field of view of 40°. The optical design shows better than 5 mm FWHM spatial resolution at the plasma on all 11 channels across the whole field of view. The spread of angle of incidence on the surface of each filter is also analyzed to inform the bandwidth specification of the interference filters. The results of the initial laboratory tests demonstrate that a spatial resolution of better than 5 mm FWHM is achieved for all 11 channels, meeting the specifications required for accurate tomography.

Citation

Feng, X., Calcines, A., Sharples, R., Lipschultz, B., Perek, A., Vijvers, W., Harrison, J., Allcock, J., Andrebe, Y., Duval, B., & Mumgaard, R. (2021). Development of an 11-channel multi wavelength imaging diagnostic for divertor plasmas in MAST Upgrade. Review of Scientific Instruments, 92(6), Article 063510. https://doi.org/10.1063/5.0043533

• Journal Article Type: Article
• Acceptance Date: May 19, 2021
• Online Publication Date: Jun 9, 2021
• Publication Date: 2021-06
• Deposit Date: Aug 23, 2021
• Publicly Available Date: Aug 23, 2021
• Journal: Review of Scientific Instruments
• Print ISSN: 0034-6748
• Electronic ISSN: 1089-7623
• Publisher: American Institute of Physics
• Peer Reviewed: Peer Reviewed
• Volume: 92
• Issue: 6
• Article Number: 063510
• DOI: https://doi.org/10.1063/5.0043533
• Public URL: https://durham-repository.worktribe.com/output/1243422