Spectroscopic Measurements of Impurity Spectra on the EAST Tokamak

• Published in: Plasma science & technology Vol. 14; no. 12; pp. 1048 - 1053
• Main Authors: Fu, Jia, Li, Yingying, Shi, Yuejiang, Wang, Fudi, Zhang, Wei, Lv, Bo, Huang, Juan, Wan, Baonian, Zhou, Qian
• Format: Journal Article
• Language: English
• Published: 01.12.2012
• Subjects: EAST; OMA系统; 光学透镜; 光谱测量; 托卡马克装置; 杂质行为; 聚变等离子体; 质谱
• ISSN: 1009-0630
• DOI: 10.1088/1009-0630/14/12/03

Ultraviolet （UV） and visible impurity spectra （200-750 nm） are commonly used to study plasma and wall interactions in magnetic fusion plasmas. Two optical multi-channel analysis （OMA） systems have been installed for the UV-visible spectrum measurement on EAST. These two OMA systems are both equipped with the Czerny-Turner （C-T） type spectrometer. The upper vacuum vessel and inner divertor baffle can be viewed simultaneously through two optical lenses. The OMA1 system is mainly used for multi-impurity lines radiation measurement. A 280 nm wavelength range can be covered by a 300 mm focal length spectrometer equipped with a 300 grooves/mm grating. The Da/Ha line shapes can be resolved by the OMA2 system. The focal length is 750 mm. The spectral resolution can be up to 0.01 nm using a 1800 grooves/mm grating. The impurity behaviour and hydrogen ratio evolution after boroniztion, lithium coating, and siliconization are compared. Lithium coating has shown beneficial effects on the reduction of edge recycling and low Z impurity （C, O） influx. The impurity expelling effect of the divertor configuration is also briefly discussed through multi-channels observation of OMA1 system.