On the intensity ratio variation of the Si IV 1394/1403 Å lines during solar flares

Hao-Cheng Yu, J. Hong, M. D. Ding

Context. The Si IV lines at 1394 Å and 1403 Å form in the solar atmosphere at a temperature of $\sim 10^{4.8}$ K. They are usually considered optically thin, but their opacity can b…