Solar Radiation Fluxes in the 10–30 nm Range from Studying the E-Region and E-F Valley

Abstract

For the 10–30 nm interval within the extreme UV region of the solar spectrum, there are no commonly accepted views on the spectral composition and absolute magnitudes of the radiation intensity due to the lack of reliable data. This region is connected with characteristics of the ionosphere heat regime, photoelectron spectrum parameters and E-F valley characteristics. For estimating the solar radiation flux by the indirect route within the spectral region from 10 to 30 nm, which is difficult for direct measurements, it is suggested to use data on the electron concentration in the E-region maximum and E-F valley. Taken from empirical models, the data on these parameters were correlated with theoretical calculations of height profiles of electron concentration in the ionosphere. Based on the proportion between electron concentration in the E-layer maximum and E-F valley minimum, the solar radiation flux within the 10–30 nm region was shown to be 2.5 times greater than that obtained in measurements on board the ‘AE-E’ and ‘AE-C satellites. The results are used for correcting model spectra of the extreme UV radiation.

Paper presented at the SOLERS22 International Workshop, held at the National Solar Observatory, Sacramento Peak, Sunspot, New Mexico, U.S.A., June 17–21, 1996.