Plasma and Fusion Research
Volume 20, 2401014 (2025)
Regular Articles
- 1)
- Institute of Liberal Arts and Sciences, University of Toyama, Toyama 930-8555, Japan
- 2)
- Department of Electrical and Electronic Engineering, Utsunomiya University, Utsunomiya 321-8585, Japan
- 3)
- Department of Advanced Science and Engineering, Hiroshima University, Higashihiroshima 739-8527, Japan
- 4)
- School of Physics, University College Dublin, Belfield, Dublin 4, Ireland
Abstract
We observed the EUV emission spectra from laser-produced tungsten plasmas. The spectral structures were compared by optical thickness due to the critical density difference of 1 × 1021 and 4 × 1021 cm−3 with laser wavelengths of 1064 nm and 532 nm, respectively. We found some spectral structure changes, an increase of emission in 1 - 3 nm region under an optically thick condition while a decrease of a peak near 5 nm for unresolved transition array of 4d - 4f transitions. Some 1.3 - 2.5 nm peaks were attributed to charge states higher than W30+. We showed some dependence of the spectral behavior for the EUV emission.
Keywords
tungsten (W), extreme ultraviolet (EUV), laser-produced plasma, highly charged ion (HCI)
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