Influence of the Neutral Atmosphere Model on the Correctness of Simulation the Electron and Ion Concentrations in the Lower Ionosphere

Abstract

The work is devoted to modeling and verification of the dynamics of charged components of the Earth's lower ionosphere, obtained using different values of the background neutral atmosphere parameters. Long‐term experimental data on temperature and concentration of neutral components from the Aura satellite and Mass Spectrometer Incoherent Scatter Radar (MSIS) model were used as input data. The average relative difference between the electron concentration values obtained using Aura and MSIS data (11 June 2014, 6–18 UT, h = 50–90 km, 41°N 10°E) was 34%. Obtained results were verified with use of very low frequency (VLF) signals propagation data, which were collected on Mikhnevo Geophysical Observatory (GPO) and A118 station from GBZ, GQD, DHO, TBB, and ICV transmitters. Based on the results of the verification, it was found that the response of the lower ionosphere to X‐ray flares, that occurred on 9–11 June 2014, is better described by the Aura satellite data in 4 out of 5 cases. Consequently, they are more preferable for predicting the state of ionospheric parameters below the reflection height of signals of the considered frequencies (∼75 km). It is also shown that taking into account the ion concentration for calculation the amplitude‐phase characteristics of the VLF‐signals makes it possible to describe the dynamics of parameters better.

Estimation of the Contribution of the Ionospheric D Region to the TEC Value During a Series of Solar Flares in September 2017

“…In this work, we used an eightcomponent plasma-chemical model of the D region (Bekker et al, 2022), the input parameters of which are real data on radiation fluxes in the UV and X-ray wavelength ranges. A distinctive advantage of this model is that it has been successfully verified using ground-based radiophysical measurements on the amplitude and phase characteristics of VLF signals reflected at the heights of the ionospheric D region (Bekker et al, 2022;Bekker & Korsunskaya, 2023). This fact makes it a reliable tool for assessing the vertical redistribution of electron concentrations during flares.…”

Estimation of the Ionospheric D‐Region Ionization Caused by X‐Class Solar Flares Based on VLF Observations

“…This fact makes the amplitude and phase of VLF signals the effective tools for assessing the state and dynamics of the lower ionosphere in quiet and disturbed conditions (Gavrilov et al, 2019). For example, VLF signals are successfully used to verify theoretical models of the medium (Bekker et al, 2022;Bekker & Korsunskaya, 2023;Xu et al, 2021Xu et al, , 2023 and to estimate X-ray fluxes during solar flares of various classes (George et al, 2019).…”