Measurement of plasma density from the ratio of intensities of resonance and intercombination lines of a He-like ion

Radiation-collision model of He-like ions of CV, FVIII, MgXI, PXIV is made. Radiation-collision coefficients of ionization and recombination and intensity ratio of resonance and intercombination lines at different Ne, Te are calculated. It is demonstrated, that the stage transitions play an important role in the formation of triplet level population density at essentially more lower densities than those for singlet levels. It is shown that possibility of Ne measurement concerning intensities of resonance and intercombination line of He-like ion is caused by knowledge of ion composition and temperature