Determination of electron density and temperature in non-LTE plasmas from spectral lines of impurity ions

An approach to determination of populations of the excited lithiumlike ions C iv, N v, O vi, and Ne viii in stationary nonequilibrium plasmas is presented. Each of these ions produces several dipole-allowed spectral lines so that the number of the available line intensity ratios is large. Consequently, the electron density and temperature can be determined by comparing some of the measured intensity ratios with their calculated values. The populations of several ionic levels, electronic partition functions, and the intensity ratios for 3 2D→2 2P/2 2P→2 2S, 3 2P→2 2S/2 2P→2 2S, 3 2S→2 2P/2 2P→2 2S, 3 2D→2 2P/3 2P→2 2S, 3 2D→2 2P/3 2S→2 2S→2 2P, and 3 2P→2 2S/3 2S→2 2P transitions are calculated in a broad range of electron density and temperature. The approach is especially useful for diagnostics of systems where nonintrusive spectroscopic techniques must be used (e.g., astrophysical and fusion plasmas).