Spectra of Ga-Like to Cu-Like Praseodymium and Neodymium Ions Observed in the Large Helical Device

Abstract

Extreme ultraviolet (EUV) spectra of highly charged praseodymium (Pr) and neodymium (Nd) ions have been investigated in optically thin high-temperature plasmas produced in the Large Helical Device (LHD), a magnetically confined torus device for fusion research. Discrete spectral lines emitted mainly from highly charged ions having 4s or 4p outermost electrons were observed in plasmas with electron temperatures of 0.8–1.8 keV. Most of the isolated lines of Ga-like to Cu-like Nd ions were identified by a comparison with the recent data recorded in an electron beam ion trap (EBIT). The isolated lines of Pr ions corresponding to the identified lines of Nd ions were easily assigned from a similarity of the spectral feature for these two elements. As a result, some of the lines of Pr ions have been newly identified experimentally for the first time in this study.

Observations and identifications of extreme ultraviolet spectra of Ca-like to Na-like neodymium ions using an electron beam ion trap

“…Recently, Suzuki et al [25] reported the first line identifications for N-shell transitions in Br-like to Ni-like Nd ions using the NIST EBIT. Another systematic observation of EUV spectra of highlycharged Nd ions was carried out in the large helical device [26]. Additional lines of Cu-, Zn-, and Ga-like ions were identified, and the reported wavelengths are in excellent agreement with the EBIT results.…”

Detailed Analysis of Spectra from Ga-like Ions of Heavy Elements Observed in High-Temperature Plasmas

“…Magnetically confined torus plasmas are considered to be appropriate for producing spectroscopic data on highly charged heavy ions because of their favorable plasma parameters and the availability of reliable diagnostic tools. From this point of view, we have so far systematically recorded EUV and soft X-ray spectra of highly charged heavy ions in high-temperature plasmas produced in the Large Helical Device (LHD), a magnetically confined torus plasma device at the National Institute for Fusion Science (NIFS) [16][17][18][19][20][21][22][23]. In order to complete the missing experimental data, this article focuses on the Z-dependent properties of the isolated spectral lines of Ga-like heavy ions observed in LHD plasmas with electron temperatures of about 2-3 keV.…”