Particle fluxes at the shock: curves represent numerical integration results, data points are results of Monte Carlo simulations. V_s = 1500   km   s^-1 (left) and V_s = 2000   km   s^-1 (right). Simulations without downstream propagation of particles are designated with ℬ = 0, whereas simulations where particles isotropise through downstream scatterings are designated with ℬ > 0. The flux differences for the reflected particles in the Monte Carlo simulations (⋄ , +) are due to statistical uncertainties. For comparison, we show the integrated flux of all particles that are faster than the classical injection threshold v > u₁ as a dash-dotted line. For κ = 15, reflected particle fluxes and the classical comparison are too low to be visible.