Solar EUV flux variation during a solar cycle as derived from ionospheric modeling considerations

Calculations in modeling the general ionospheric structure observed during solar minimum and solar maximum suggest that the Hinteregger (1970) solar EUV flux values are adequate for modeling the mid-latitude ionospheric structure during solar minimum. However, these flux values should be doubled for modeling solar maximum conditions. The calculations also suggest that the atomic oxygen density at 120 km was approximately a factor of 2 lower during solar cycle minimum than during solar cycle maximum.