We observed M1. 9 class solar flare in NOAA 10808 active region by the HSFA spectrograph of Ondřejov observatory. We registered emission in hydrogen H, H, H lines and in H, K CaII lines. After the spectra processing the integral emission fluxes were derived. In the Joule heating framework we conducted calculation of gas parameters utilizing the physical conditions of the chromosphere, particularly self-absorbtion at spectral lines. All general populating and depopulating processes of discrete energetic levels were taken into account. We considered model of gas layers oriented perpendicular to the line of sight. Registered emission in five lines needed two-layered model for interpretation. The farther one has temperature 7300 K and concentration 10^14 cm ^-3. The nearby layer has has temperature 30000 K and concentration 10^12 cm ^-3.
Maliutin et al. (2025) studied this question.