Electron density diagnostics for solar ultraviolet lines of O V

Abstract

We determine the electron densities for a range of solar features using new calculations for the O v line ratio, R=I(λ761.1)/I(λ760.4), in conjunction with observational data obtained with the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) instrument on the Solar and Heliospheric Observatory (SOHO). The densities obtained from this diagnostic are in good agreement with earlier measured values. This provides support for the theoretical diagnostics presented in this paper, and hence the atomic data used in their derivation. We conclude from these results that this particular O v ratio is a useful diagnostic for many types of solar features.