GRTTM instantaneous energy deposits (left) and HXR spectra (right) for the primary (top) and secondary (bottom) footpoints and the VAL C atmosphere at t = 0.3 s. The green, red, and orange solid (M^FF) and dotted (M^SU) lines correspond to the current densities j = 1,3,6 A m^-2, respectively, and to the energy flux ℱ₀/2 = 2.5 × 10⁹ erg cm^-2 s^-1. The grey dashed and solid lines correspond to the CTTM with ℱ₀/2 = 2.5 × 10⁹ and 5 × 10¹⁰ erg cm^-2 s^-1, respectively. The dotted straight vertical line indicates the bottom boundary of the magnetic mirror. The HXR spectra are integrated over one half of the loop.