Fig. 2

Large panel: comparison of density distribution obtained from the test particle simulation for two shocks (thick solid line), theoretical model based on the diffusion convection equation with constant diffusion coefficient (dotted line), and the same model that takes into account the dependence of the diffusion coefficient on the cosmic ray energy (thin solid line). The two blue lines with indices − 4 and − 2 are indicated for reference. Test particles are injected at both “Shock 1” and “Shock 2.” Small panel: density distribution obtained by the test particle simulation for one single shock