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

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.