Spectroscopic diagnostics for the N III ion

Spectroscopic diagnostics for the Niii ion have been studied using an atomic model including the first eleven energy levels and taking account of various physical processes. New calculations for the line emissivities as a function of electron density and temperature have been carried out. Density-sensitive and temperature-sensitive line emissivity ratios are presented and their diagnostic applications to the solar atmosphere are discussed with the help of available observations.Paper presented at the IAU Colloquium 154 on Solar and Interplanetary Transients, Pune, 1995 January 23–27.