Wavelength measurements of the satellite transitions to the n=2 resonance lines of helium-like argon

The wavelengths of the 1s2s2p-1s(2)2s and 1s2p(2)-1s(2)2p transitions in Ar15+ have been measured using a crystal spectrometer and an electron beam ion trap. These spectral lines are satellites to the n = 2 resonance lines of He-like Ar16+ and play an important diagnostic role in high-temperature plasmas directed toward fusion research. The results of these measurements are compared with a number of different theoretical results, demonstrating the relative accuracy of these theoretical approaches.