Electron Density Diagnostics for the Solar Upper Atmosphere from Spectra Obtained by SUMER/SOHO

Abstract
We evaluate the electron density in various solar regions above the limb observed by the Solar Ultraviolet Measurement of Emitted Radiation (SUMER) instrument on SOHO. We find in general good agreement among line ratios from Be-, B-, N-, and Mg-like ions, giving densities of order 108 cm-3.