An excitonic model for the electron–hole plasma relaxation in proton-irradiated insulators Lorenzo Stella, Jonathan Smyth, Brendan Dromey and Jorge Kohanoff Eur. Phys. J. D, 75 7 (2021) 203 Published online: 15 July 2021 DOI: 10.1140/epjd/s10053-021-00215-3