Line identification of extreme ultraviolet spectra from aluminum ions in EAST Tokamak plasmas

Abstract

Extreme ultraviolet (EUV) spectra emitted from aluminum in the 5-340 Å wavelength range were observed in Experimental Advanced Superconducting Tokamak (EAST) discharges. Several spectral lines from aluminum ions with different degrees of ionization were successfully observed with sufficient spectral intensities and resolutions using three fast-time-response EUV spectrometers. The line identification uses three independent state-of-art computational codes for the atomic structure calculations, which provide the wavelengths and the collisional and radiative transition rate coefficients. These programs are hullac (Hebrew University—Lawrence Livermore Atomic Code), autostructure, and fac (Flexible Atomic Code). Using three different codes allows us to resolve some ambiguities in identifying certain spectral lines and assess the validity of the theoretical predictions.