We present detailed EUV spectra of 4 large solar flares : M5.6 , X1.3 , X3.4 , and X17 classes in the spectral ranges 176–207 Å and 280–330 Å .
These spectra were obtained by the slitless spectroheliograph SPIRIT aboard the CORONAS-F satellite .
To our knowledge these are the first detailed EUV spectra of large flares obtained with spectral resolution of \sim 0.1 Å .
We performed a comprehensive analysis of the obtained spectra and provide identification of the observed spectral lines .
The identification was performed based on the calculation of synthetic spectra ( CHIANTI database was used ) , with simultaneous calculations of DEM and density of the emitting plasma .
More than 50 intense lines are present in the spectra that correspond to a temperature range of T = 0.5 - 16 MK ; most of the lines belong to Fe , Ni , Ca , Mg , Si ions .
In all the considered flares intense hot lines from Ca xvii , Ca xviii , Fe xx , Fe xxii , and Fe xxiv are observed .
The calculated DEMs have a peak at T \sim 10 MK .
The densities were determined using Fe xi–Fe xiii lines and averaged 6.5 \times 10 ^ { 9 } cm ^ { -3 } .
We also discuss the identification , accuracy and major discrepancies of the spectral line intensity prediction .