Solar flares in Halpha and Ly-alpha : observations vs simulations

In order to study the properties of faint, moderate and bright flares, we simulate the conditions of the solar atmosphere using a radiative hydrodynamic model \citep{2005ApJ...630..573A}. A constant beam of non-thermal electrons is injected at the apex of a 1D coronal loop and heating from thermal soft X-ray and UV emission is included. We study the contribution of different processes to the total intensity of different lines at different atmospheric layers. We obtain the total integrated intensity of different lines and we compare those of the Ly-alpha and Halpha lines with the observational values for Ly-alpha (using TRACE 1216 and 1600 Å data and estimating the ``pure'' Ly-alpha emission) and Halpha (using data from the Ondřejov Observatory). We inferred from the analysis of the values obtained by simulation that the X-ray energy of the different kind of flares does not strongly affect the Ly-alpha results; the Halpha results are comparable to the observed ones, concluding that the simulated solar atmosphere fits better at lower layers of the chromosphere than at upper layers.