A formula for calculating theoretical photoelectron fluxes resulting from the He+ 304 Å solar spectral line

Abstract

We present a method for evaluating the ionospheric photoelectron fluxes resulting from the 304 Å solar radiation. This method can be used to verify the full theoretical calculation of these specific photoelectron fluxes. The formula may also be useful in monitoring variations in the 304 Å solar flux whenever direct solar flux measurements are unavailable. We have also performed photoelectron flux calculations using two different sets of inelastic electron collision cross sections. Fluxes obtained using an old set of cross sections are in good agreement with measured fluxes from Atmosphere Explorer‐E but are up to a factor of two larger at energies between 20 and 30 eV than fluxes from most other previously published theoretical calculations. However, spectra obtained with a newer larger set of collision cross sections are in agreement with the other theoretical models, but not with the measured spectra. This suggests that the disagreement between ionospheric photoelectron theory and experiment might be resolved by a review of the electron collision cross sections used in the theoretical models.