Tungsten spectroscopy at the Livermore electron beam ion trap facility1This review is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

Abstract

The utilization of tungsten spectroscopy for diagnostics of magnetically confined fusion plasmas requires the radiative properties of tungsten ions to be accurately known. At the Lawrence Livermore National Laboratory, a program to gather spectroscopic data on tungsten ions has been initiated with the purpose to study spectral signatures and identify candidate fusion plasma diagnostics. In this paper, an overview of recent results from the Livermore WOLFRAM spectroscopy project is presented, which includes experimental investigations at the EBIT-I and SuperEBIT electron beam ion traps. In particular, the spectra of highly charged M- and L-shell tungsten ions have been studied. These investigations cover energy measurements of n = 2 to n = 2, 3 transitions in Ne-like W64+ through Li-like W71+ ions and soft X-ray measurements of n = 3 to n = 3, 4 transitions in M-shell ions with emphasis on the Ni-like W46+ and Si-like W60+ through Na-like W63+ ions. The measurements are complemented by atomic-structure calculations and spectral modeling using the Flexible Atomic Code (FAC).