Unresolved Dielectronic Satellites of the Resonance Line of Heliumlike Iron (Fe XXV)

High-resolution spectra of Fe xxv have been observed from Princeton Large Torus tokamak discharges and are used for a detailed comparison with theoretical predictions of Bely-Dubau, Gabriel, and Volont\'e for the (1s²nl-1s2pnl, $n>~3$) dielectronic satellites at 1.85 {}. The theory predicts a significant apparent broadening of the resonance lines of high-Z heliumlike ions in high-temperature plasmas due to the dielectronic capture of electrons into outer atomic shells. The experimental results and theoretical predictions are in good general agreement.