Cascades between doubly excited levels in helium-like argon

Helium-like spectra produced by photon emission of ions with intermediate Z represent an important diagnostic for fusion plasmas and solar flares. In this work, the influence of the radiative transitions among doubly excited levels on the intensity of the associated dielectronic satellites (1s 2 nl –1s2 lnl ′) is analysed. Special attention is paid to the comparison between inner-shell excited satellites of n = 2 and different theoretical calculations. We described the group of n = 3 and n = 4 dielectronic satellites taking into account additional radiative channels to the group of n = 2. Cascade contributions have been verified in experimental spectra of argon from the tokamak TEXTOR. We have compared the intensity of all resolved satellites of n = 2 and the group of n = 3 with experiment. The internal consistency for the satellites with and without inner-shell excitation part has been achieved. Most important is the effect on the measurement of lithium-like ions, determined from the collisional satellites. The measured concentrations prove the prediction of transport simulation, taking into account the diffusion of ions and charge exchange recombination. The strong satellites of n = 2, providing the results on electron temperature, are found to be not sensitive to the cascades.