Coherence imaging of scrape-off-layer and divertor impurity flows in the Mega Amp Spherical Tokamak (invited)

Silburn, S.A.; Harrison, J.R.; Howard, J.; Gibson, K.J.; Meyer, H.; Michael, C.A.; Sharples, R.M.

Abstract

A new coherence imaging Doppler spectroscopy diagnostic has been deployed on the UK’s Mega Amp Spherical Tokamak for scrape-off-layer and divertor impurity flow measurements. The system has successfully obtained 2D images of C III, C II, and He II line-of-sight flows, in both the lower divertor and main scrape-off-layer. Flow imaging has been obtained at frame rates up to 1 kHz, with flow resolution of around 1 km/s and spatial resolution better than 1 cm, over a 40° field of view. C III data have been tomographically inverted to obtain poloidal profiles of the parallel impurity flow in the divertor under various conditions. In this paper we present the details of the instrument design, operation, calibration, and data analysis as well as a selection of flow imaging results which demonstrate the diagnostic's capabilities.

Citation

Silburn, S., Harrison, J., Howard, J., Gibson, K., Meyer, H., Michael, C., & Sharples, R. (2014). Coherence imaging of scrape-off-layer and divertor impurity flows in the Mega Amp Spherical Tokamak (invited). Review of Scientific Instruments, 85(11), Article 11D703. https://doi.org/10.1063/1.4891165

• Journal Article Type: Article
• Acceptance Date: Jul 1, 2014
• Online Publication Date: Aug 1, 2014
• Publication Date: Nov 1, 2014
• Deposit Date: Aug 4, 2014
• Publicly Available Date: Aug 5, 2014
• Journal: Review of Scientific Instruments
• Print ISSN: 0034-6748
• Electronic ISSN: 1089-7623
• Publisher: American Institute of Physics
• Peer Reviewed: Peer Reviewed
• Volume: 85
• Issue: 11
• Article Number: 11D703
• DOI: https://doi.org/10.1063/1.4891165
• Public URL: https://durham-repository.worktribe.com/output/1455943