التفاصيل البيبلوغرافية
| العنوان: |
Estimation of the Contribution of the Ionospheric D Region to the TEC Value During a Series of Solar Flares in September 2017. |
| المؤلفون: |
Bekker, S. Z., Ryakhovsky, I. A. |
| المصدر: |
Journal of Geophysical Research. Space Physics; Jun2024, Vol. 129 Issue 6, p1-12, 12p |
| مصطلحات موضوعية: |
SOLAR flares, X-ray spectra, INCOHERENT scattering, SOLAR radiation, GLOBAL Positioning System, ULTRAVIOLET radiation |
| مستخلص: |
The paper presents the results of a numerical assessment of the contribution of the ionospheric D region to the total electron content during six powerful X‐ray flares that occurred in September 2017. The calculation of the electron concentration in the lower ionosphere was carried out using a plasma‐chemical model of the ionospheric D region. This model was verified using the data of ground‐based radiophysical measurements in the VLF (very low frequency) range and data of the incoherent scattering radar. To calculate the ionization rate at the D region heights, we used real data on the radiation flux measured by the GOES and SDO satellites during the considered flares. The total electron content was estimated using GNSS data. As a result of the analysis, it was found that the contribution of the lower ionosphere to the TEC change varied from 7% to 23% for flares with different spectra. A functional dependency has been obtained that can be used to estimate the contribution of the D region to the TEC increment depending on the spectrum of the flare. Key Points: A technique for estimating the redistribution of the electron concentration in the ionosphere during solar flares is presentedIt was found that the contribution of the D region to the TEC change varied from 7% to 23% during the flares in September 2017A functional dependency of the D region contribution to the TEC change on the fraction of X‐rays in the flare spectrum is obtained Plain Language Summary: Changes in solar radiation fluxes are observed in a wide range of wavelengths during solar flares. The variations of total electron content in the ionosphere occurs due to an increase in radiation in the UV and X‐ray wavelength ranges. The main increase in ionization caused by flares occurs in the F region (h > 120 km), so the electron concentration increment in the lower part of the ionosphere (h < 90 km) is often neglected. The existing experimental measurement methods do not allow us to estimate the redistribution of the electron concentration in the ionosphere during disturbances; therefore, to estimate the contribution of the lower ionosphere to the total electron content during flares, we used GNSS data and theoretical plasma‐chemical model of the D region. In this work, it is shown that the contribution of the D region to the change of the total electron content can reach 23% during X‐ray flares. [ABSTRACT FROM AUTHOR] |
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