Spectra of nuclei and their ratios versus rigidity. Top panels: spectra of primary CR nuclei of helium (a), carbon (b), and nitrogen (c). Bottom panels: abundance ratios of stable secondary to primary nuclei, represented by the boron-to-carbon ratio (d), as well as of unstable to stable secondary nuclei, represented by the beryllium-to-boron (e) and the beryllium-10-to-beryllium-9 (f) ratios. Our numerical results without and with taking into account the ion-neutral damping are plotted, respectively, by the dashed and solid lines. The symbols depict the observational data: preliminary AMS-02 data for the ¹⁰Be/⁹Be ratio (Derome & Paniccia 2021) and their recent update (Wei 2023) are represented in the bottom right panel by the black crosses and squares, respectively.