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论文类型：期刊论文

发表时间：2017-11-01

发表刊物：Spectrochimica Acta - Part B Atomic Spectroscopy

收录刊物：EI、CPCI-S、Scopus、SCIE

卷号：137

页面范围：77-84

ISSN号：05848547

关键字：Magnetic field; Lithium plasma; Excited state; Recombination cross-section; Libs

摘要：In this paper, the effect of magnetic field (1.1 T) on the atomic and ionic spectral emission of a laser produced lithium plasma at low pressure has been investigated. The experimental results indicate that magnetic field enhances the intensities of Li I spectral lines but reduces the Li II spectral lines intensities. In this study, two narrowband filters were placed before the ICCD camera to observe the evolution feature of Li II spectral line (548.39 nm, 2p3P2,1,0   2s3S1) and Li I spectral line (610.30 nm, 3d2P3/2, 5/2   2p2P1/2, 3/2), respectively. The plasma dynamic images show that with the magnetic field, the number density of luminous Li atoms is higher, while the number density of luminous Li ions is lower in comparison to the field-free case. The reduced Li II spectral intensities indicate that the quenching rate of Li ions in the excited state is greater than that without the magnetic field. The enhanced impact frequency of recombination indicates that magnetic field increases the recombination process of electron and Li ions. All of these observations strongly suggest that magnetic confinement increases the recombination process of the electrons with Li ions in the plasma, which results in the decrease in the intensity of Li II line. The results are useful for applying laser-induced breakdown spectroscopy (LIBS) to in-situ diagnose the processes of lithium wall conditioning in EAST tokamak. ? 2017 Elsevier B.V.