The time history of the temperature and the emission measure of the solar flare plasma have been studied relying upon the experimental data on the soft X-rays recorded by the IRIS spectrometer on June 29, 2002 (F1) and March 27, 2003 (F2). F1 was a thermal one and was not accompanied by hard X-rays. This data analysis revealed that at least two sequential energy-release processes occurred during F1 event. F2 event took place behind the limb, so only the top part of the flare loop being the soft X-ray source was recorded by the satellite-based spectrometer. From this data analysis it appeared that the fast plasma heating occurred in the initial stage of F2 and then the flare region expanded and the emission measure of flare plasma increased.

Citation: M.I. Savchenko, P.V. Vatagin, V.P. Lazutkov, D.V. Skorodumov, I.V. Kudryavtsev, Yu.E. Charikov, The two solar flares diagnostics based on the soft X-ray emission recording, St. Petersburg Polytechnical State University Journal. Physics and Mathematics. 10 (3) (2017) 152–160. DOI: 10.18721/JPM.10314