Energy density U_CR as a function of the particles’ effective radius r (upper row) and kinetic energy E (lower row). Left column: the time-dependent evolution of U_CR corresponds to the no loss case of E ∈ 10^[1, 7] GeV, where the color bar shows the simulation time in units of yr. In panel (c), the U_CR distribution of the several initial snapshots is shown in the inset. Right column: U_CR distributions in four different energy regimes plotted at the final snapshot (t = 3 kyr), where the dashed and solid lines show the results without and with loss processes, respectively. Simulations are based on the related parameters in Group 𝒜.