Abstract
An experimental study was made of the dependence of the electron-density perturbations in the D‑regions of the midlatitude ionosphere during solar flares on the spectral composition of X-ray radiation in the wavelength range from 0.01 to 0.4 nm, i.e., outside the measurement range of the GOES satellite. For this, the variation in the brightness temperature of the emission of six flares in 2014–2017 were calculated, and the composition of their radiation was determined. It is shown that, although only a small percent of the total flash radiation energy is in the 0.01–0.2 nm wavelength range, it is the hard components that are the main factor leading to a change in the reflection height of very low frequency (VLF) radio waves. It is shown that the efficiency of solar flares significantly depends on the previous solar activity, not only for class-C flares but also for powerful class-M and -X flares.
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The study was performed within the framework of a state task АААА-А17-117112350014-8.
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Gavrilov, B.G., Poklad, Y.V., Ryakhovsky, I.A. et al. Dependence of D-Region Perturbations of the Midlatitude Ionosphere on the Spectral Composition of the X-Ray Radiation of Solar Flares According to Experimental Data. Geomagn. Aeron. 62, 98–103 (2022). https://doi.org/10.1134/S0016793222020086
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DOI: https://doi.org/10.1134/S0016793222020086