Panel a: Synthetic Hα spectrum at t = 4414 s. The image displays the synthesized spectrum for comparison with Ellerman’s observations from 1917, with the horizontal axis representing wavelength and the vertical axis representing the length along the dashed red line in Fig. 6. The dashed red line in Fig. 6a acts as an imaginary spectrograph slit. Panels b to d present physical quantities in the y − z plane along the dashed red line indicated in Fig. 6. In panel b, the temperature distribution is shown, with the gray and black lines representing the locations where the optical depths of the Hα wing (−0.5 Å) and Hα line center reach unity, respectively. Panel c displays the vertical velocity (vz) distribution, panel d shows the emissivity of Si IV, and panel e displays the synthesized Si IV spectral line profile calculated from the blue rectangular region marked in Fig. 6b.