ORIGIN OF SPECTRAL HARDENING OF SECONDARY COSMIC RAY NUCLEI

We discuss the production, acceleration and escape of secondary cosmicray (CR) nuclei, such as lithium, beryllium, and boron, produced by spallation of primary CR nuclei at the shock in supernova remnants (SNRs). We find that if the SNR is surrounded by a dense circumstellar medium which has a wind-like profile, the spectra of the escaping secondary nuclei are harder than those of the escaping primary nuclei. We show that if there was a past supernova surrounded by a dense wind-like CSM at a distance of similar to 1.6 kpc, we could simultaneously reproduce the spectral hardening of primary and secondary CRs above similar to 200 GV that have recently been reported by AMS-02.