Correlation of an electron’s relative energy gain with its highest experienced value of r_L/L_B. In this ensemble, the GCA tolerance was 10⁻², hence the abrupt cutoff at r_L/L_B = 10⁻². The colour maps the counts on a logarithmic scale. The non-thermal electrons in the cluster around the O-type null point (of Fig. 5) are shown in blue. They all fall within the diagonal strand in the upper-right part of the histogram, where the relative energy gain is above 1 and r_L/L_B is above 10⁻⁴. The non-thermal electrons in the cluster around the X-type null point are shown in green and fall within the more diffuse diagonal strand below.