The potential for plasma diagnostics from stellar extreme-ultraviolet observations

Based on 20 years of solar investigations, the extreme-ultraviolet (EUV) spectrum in the range 50-500 A has proved to be extraordinarly rich in providing information on the density, temperature, and element abundances of the plasma in the Sun's chromosphere and corona, especially when observed with high spectral resolution. A description of the lines form the most abundant ions in this spectral region that have special diagnostic significance is presented