Impact of adiabatic energy loss on the particle energy spectrum as described by Eq. (9). We set an initial flux spectrum with parameters j₀ = 10⁸[#/cm²/s/sr/MeV], γ = 4, and a constant solar wind speed of V_sw = 450 [km/s]. Panel a shows the peak flux spectrum at 1 AU for different diffusion coefficient indexs, α. Panel b shows the adiabatic energy loss of particles with a given initial energy corresponding to Panel a. Panel c shows the peak flux spectrum at 1 AU with different diffusion normalization coefficients, κ₀. Panel d shows the adiabatic energy loss of particles with a given initial energy corresponding to Panel c. Panel e shows the evolution of the peak flux spectrum at different heliocentric distances. Panel f shows the adiabatic energy loss corresponding to Panel e.