Abstract
Abstract
Extreme ultraviolet (EUV) spectra emitted from iron and copper ions in a range of 8–500 Å and molybdenum ions in a range of 8–400 Å were measured in Experimental Advanced Superconducting Tokamak (EAST) discharges accompanied with spontaneous sputtering events, by which metallic impurity influxes are suddenly increased in the discharge. Several spectral lines from L-, M-, and N-shell partially ionized ions have been successfully observed with two EUV spectrometers named EUV_Short and EUV_Long working in wavelength ranges of 8–130 Å and 20–500 Å, respectively. The wavelength position is accurately calibrated in-situ based on several well-known spectra of low-Z impurity ions. The line identification is carefully performed based on the National Institute of Standards Technology (NIST) database and previously published experimental data. As a result, it is found that B-, Be-, and Li-like iron and copper spectra Al-, Mg-, and Na-like molybdenum spectra appear in discharges with high central electron temperature (>1.8 keV). The highest ionization stages identified here are Li-like iron and copper and Na-like molybdenum, e.g. Fe XXIV at 192.028 Å (1s22p 2P3/2 → 1s22s 2S1/2), Cu XXVII at 153.513 Å (1s22p 2P3/2 → 1s22s 2S1/2) and Mo XXXII at 127.868 Å (2p63p 2P3/2 → 2p63s 2S1/2). Two unresolved transition arrays of molybdenum ions (Mo-UTAs) appear at wavelength ranges of 15–30 Å and 65–95 Å, and are preliminarily identified as Mo XX-Mo XXXII and Mo XVII-Mo XXXII, respectively. In addition, six spectral lines are newly found by comparing a time evolution of the line intensity from impurity ions in different ionization stages, i.e. Fe XVIII at 17.60 ± 0.02 Å, Cu XXI at 13.15 ± 0.02 Å, Cu XVIII at 260.32 ± 0.07 Å, Cu XVIII at 261.00 ± 0.06 Å, Mo XXVIII at 85.30 ± 0.03 Å and Mo XXIX at 89.59 ± 0.03 Å. The wavelengths of EUV spectra identified in this work are summarized in tables with transitions for each impurity species.
Funder
National Key Research and Development Program of China
Chinese Academy of Sciences President’s International Fellowship Initiative
National Natural Science Foundation of China
the Fundamental Research Funds for the Central Universities
Subject
Condensed Matter Physics,Mathematical Physics,Atomic and Molecular Physics, and Optics
Cited by
11 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献