secondary injection rate arising from inelastic processes converting heavier species of index $\beta$ into $\alpha$ species (with a production rate $ 
\sigma_{\beta\to \alpha}v_\beta n_{\rm ism}$ on the ISM density $n_{\rm ism}$, or a decay rate $\Gamma_{\beta\to\alpha}$). This source term is balanced by several other terms, among which the decay rate $\Gamma_{\alpha}$ (if relevant). The central piece of the propagation equation is the spatial diffusion coefficient $K$, that we discuss in more detail in . The other processes are mostly relevant at low rigidity, but may still affect the determination of higher-energy parameters: convection is featured by a velocity $\vec{V}_{\rm c}$, diffusive reacceleration is parameterized by the energy-dependent coefficient $K_{pp}$, and the inelastic destruction rate is given by $\sigma_{\alpha}v_\alpha n_{\rm ism}\, \psi_\alpha$, with the $\sigma$’s being energy-dependent nuclear cross sections; energy losses are characterized by the rate $b_{\rm tot}\equiv dE/dt$, which includes ionization and Coulomb processes as prescribed in [@MannheimEtAl1994; @StrongEtAl1998], as well as adiabatic losses induced by convection and reacceleration, see [@MaurinEtAl2002a; @PutzeEtAl2010].

Finally, we can switch from the interstellar (IS) CR flux predictions to the top-of-atmosphere (TOA) ones by means of the force-field approximation [@GleesonEtAl1968a; @Fisk1971], for which we only indicate the Fisk potential $\phi_{\rm F}$. The latter is 