Comparison and Verification of the Different Schemes for the Ionization‐Recombination Cycle of the Ionospheric D‐Region

Abstract

The issue of modeling the Earth's lower ionosphere in calm and disturbed conditions remains one of the most urgent issues in atmospheric research. The difficulty of obtaining experimental data at heights of the D-region (50-90 km) hinders the construction of good quality empirical models of ionospheric parameters; therefore, the dynamics of the component concentrations under conditions of disturbances (e.g., X-ray flares) are typically described by theoretical models of varying complexity. Considering the dynamics of a large number of charged and small neutral components allows, a more detailed and interconnected description of the photochemistry of the medium (

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

“…An analysis of the spatial variation of the signal amplitude on this path showed that the receiver point is near the area of the interference minimum during strong flares. Bekker et al (2022) demonstrated that this effect leads to the fact that the amplitude values become unstable and respond to the slightest deviations of the theoretical Ne concentration from the true ones. Therefore, we can conclude that such single discrepancies do not refute the efficiency of the eight-component plasma-chemical model used for calculating the concentrations of charged particles.…”

“…. The input parameters of the model are the ionization rate q, 58 different reaction rates and rate constants listed in Bekker et al (2022), and the neutral atmosphere parameters-temperature of neutrals T, concentrations of main…”

“…As a result, the amplitude A and phase ϕ of the propagating VLF‐signals are distorted, so they can be used both to reconstruct the state of the medium in calm and disturbed condition, as shown in the work of Gavrilov et al. (2019), and to verify the existing theoretical models (Bekker et al., 2022).…”

“…Taking into account the above, the use of theoretical plasma-chemical models of the lower ionosphere, which describe the behavior of a small number of ionospheric components, remains a fairly promising direction of research (Bekker et al, 2021(Bekker et al, , 2022Glukhov et al, 1992;Kozlov et al, 2014;Xu et al, 2023). To calculate the dynamics of the Ne and the main positive and negative ions of the lower ionosphere, an eight-component model of the ionospheric D-region (Bekker et al, 2022) is used in this work. The main advantage of this scheme compared to multicomponent global models is a significantly smaller number of input parameters.…”

Estimation of the lower ionosphere ionization caused by X-class solar flares, based on VLF observations

“…Electromagnetic radiation caused by solar flares of various classes has a significant impact on the height profile of the electron concentration of the entire ionosphere. The D-region is the most difficult for experimental and theoretical study (Bekker et al, 2021(Bekker et al, , 2022. During solar flares flux of X-ray radiation of the Sun penetrates into D-region and increases electron concentration by several times due to additional ionization (Mitra, 1974;Kumar & Kumar, 2018).…”