Heuristic model of solar X-ray spectrum according to satellite data for geophysical applications

Abstract

Model and computational algorithm for recovering the X-ray component of the solar spectrum based on GOES XL (0.1–0.8 nm), XS (0.05–0.4 nm or 0.05–0.3 nm) and SDO QD (0.1–7 nm) channels data are presented. The model based the Mewe approximation of emission from optically thin plasmas that presents a temperature-like spectrum. The possibility to present the result spectrum as a superposition of Mewe spectrums placed in the solar absorbing atmosphere at one optical depth for its temperature parameter energy is suggested in this paper. So the model is a variation of the multi-temperature approximation. Spectrum parameters are determined on the basis of support functions, approximation expressions for which are given in appendix.

Modeling of the Lower Ionosphere During Solar X‐Ray Flares of Different Classes

“…The amplitude dynamics simulation is not correct in the part following the flare start at 08:00 UT. The current heuristic model of the radiation spectrum and ionization of the lower ionosphere (Korsunskaja, 2019) does not describe ultrahard X ‐radiation, which could be the reason for the difference between the theoretical and experimental results. Analysis of the Sun's radiation spectrum based on RHESSI observatory data (http://sprg.ssl.berkeley.edu/%2Ctohban/browser/) has proven the presence of ultrahard X ‐radiation in this flare.…”

“…The spectral density of the photons was calculated from measurements in the XL (0.1–0.8 nm) and XS (0.05–0.4 nm) channels of the GOES‐13 and ‐15 satellites (with correction) and the QD channel (0.1–7 nm) of the SDO satellite (Woods et al., 2012) according to the HMSXS model (Korsunskaja, 2019). Satellite data averaged with a step of 1 min were used.…”

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

“…To calculate the ionization rate in the UV and X-ray wavelength ranges, we used solar flux data measured by the Geostationary Operational Environmental Satellite (GOES) (115-127 nm, 0.1-0.8 nm, 0.05-0.4 nm) and Solar Dynamics Observatory (0.1-7 nm) satellite (Machol & Viereck, 2016;Woods et al, 2012). Bekker et al (2021Bekker et al ( , 2022 and Korsunskaja (2019) described detailed algorithm for calculating the ionization rate by various radiation sources, so it is not presented in this paper. Concentrations of neutral components are used to calculate the ionization rate q, so they additionally affect the solutions of the system of differential equations through this parameter.…”

“…Bekker et al. (2021, 2022) and Korsunskaja (2019) described detailed algorithm for calculating the ionization rate by various radiation sources, so it is not presented in this paper.…”

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

“…The ionization of NO molecules in the range 102.57-134 nm, O 2 molecules in the range 101-102.57 nm, and O 2 ( 1 Δ g ) molecules in the range 102.57-118 nm (http://satellite.mpic.de/spectral_atlas/ cross_sections/) were considered to calculate the ionization in the UV range. The method for calculating the ionizing effect of the Sun based on the data of the GOES and SDO satellites is described in more detail in Bekker et al (2021), Korsunskaja (2019).…”