GRTTM summary of calculated parameters of chromospheric bombardment for various current densities j. The solid lines and asterisks denote the M^FF, the dashed lines and triangles denote the M^SU. Left: chromospheric energy deposit ℰ_ch (lines) and fitted energy flux (symbols) (top), the ratio ℱ_R/ℱ₀(bottom) for the primary (blue) and secondary (green) footpoints. Right: position of energy deposit maximum s_max and HXR intensity I_25 keV (top), HXR spectral index γ_25 keV, fitted electron beam spectral index and low-energy cutoff (bottom) only for the primary footpoint.