Electron energy distribution at ﹩r=100﹩ km as calculated with ﹩Q=2\times {10}^{27}\,{{\rm{s}}}^{-1}﹩ and ﹩u=1\,{{\rm{km\, s}}}^{-1}﹩. Results from our model based on the continuous slowing-down approximation (CSDA) is shown in black while results from a test-particle (TP) model (as described in Section 5.2.2) is shown in red. The fractions of electrons in the lowest energy bin are, as indicated, ~0.46 and ~0.50, for the CSDA model and TP model, respectively.