Modelled HXR flux distribution with distance from the footpoint along the flare loop, produced using Eqs. (4) and (5) and assuming example density parameters H_r = 10⁹cm, N_r = 2.43 × 10¹⁹cm^-2, and a = 0.9. Four sample spectral index values are input at a photon energy of 7 keV. Since z- and δ-independent factors are neglected, the distributions are normalised such that they peak at 1; however, the location of the peaks and the relative scaling between plots of different index are accurate. The height at which dI/dz distributions are at their maximum (z_max) is noted, illustrating the HXR source height’s dependence on spectral index. For lower spectral indices, the height at which dI/dz is at its maximum value is lower in the model flare loop.