Showing papers by "Hiroyuki A. Sakaue published in 2023"
TL;DR: In this paper , the tungsten Unresolved Transition Array (UTA) spectrum was observed in the wavelength ranges of extreme ultraviolet (EUV) 6-60 Å and 130-340 Å, and the electron temperature dependence of the UTA spectral shape was investigated in the region < 4.3 keV.
Abstract: Spectroscopic studies of emissions released from tungsten ions combined with a pellet injection technique have been conducted in the Large Helical Device. The tungsten Unresolved Transition Array (UTA) spectrum was observed in the wavelength ranges of extreme ultraviolet (EUV) 6–60 Å and 130–340 Å, and the electron temperature dependence of the UTA spectral shape was investigated in the electron temperature region < 4.3 keV. The UTAs of W24+–W33+ at 20–33 Å, W37+–W42+ at 45–47 Å, W27+–W29+ at 48–55 Å, and W7+– W27+ at 170–210 Å were observed. Unidentified UTAs were also found at 230–270 Å and 280–320 Å. As the electron temperature increased further above 4 keV, the W37+–W42+ UTA at 45–47 Å was maintained, while the other UTAs became less intense.
TL;DR: In this paper , a compact electron beam ion trap (CoBIT) was used to identify magnetic dipole transitions between the levels of the 4f125p1 and 4f13 configurations.
Abstract: To provide spectroscopic data for W13+, the present work is focused on the analysis of spectra observed in the visible range, using a compact electron beam ion trap (CoBIT). Line identification is done by using a collisional radiative model, along with sophisticated structure calculations from FAC and GRASP2018. Most of the identified lines belong to magnetic dipole (M1) transitions between the levels of the 4f125p1 and 4f13 configurations.
TL;DR: In this paper , the authors performed the measurements of charge exchange spectroscopy for multiply charged Er ions in the visible light range and reported observed emission lines from multiply charged er ions.
Abstract: The origin of heavier elements than iron is still under discussion, and recent studies suggest that the contribution of the r-process in neutron star mergers is dominant. Future modeling of such processes will require a huge amount of spectroscopic data on multiply charged ions of heavy elements. However, these experimental data are extremely scarce for heavy elements. In this work, we have performed the measurements of charge exchange spectroscopy for multiply charged Er ions in the visible light range. We report observed emission lines from multiply charged Er ions and their identification based on theoretical estimates.
TL;DR: In this article , the energy dependence of the intensity ratio between the 3s3p 3 P 2-3s3d 3 D 3 transition at 233.9 Å and the 3 s3p 1 P 1-3d 1 D 2 transition at 243.8 Å in Fe xv was studied with an electron beam ion trap over an energy range that spans resonance excitation regions.
Abstract: We present the energy dependence of the intensity ratio between the 3s3p 3 P 2—3s3d 3 D 3 transition at 233.9 Å and the 3s3p 1 P 1—3s3d 1 D 2 transition at 243.8 Å in Fe xv studied with an electron beam ion trap over an energy range that spans resonance excitation regions. Clear resonance structures are observed in the electron energy range of 400–600 eV. The energy dependence obtained in the experiment is compared with a collisional-radiative model calculation, including resonance excitations, and overall agreement is found. It is shown that the ratio strongly reflects the population of the 3s3p 3 P 2 metastable state, which is the lower state of the 233.9 Å transition.