Proton polytropic behavior of periodic density structures in the solar wind C. Katsavrias, G. Nicolaou, S. Di Matteo, L. Kepko, N. M. Viall, S. Aminalragia-Giamini and G. Livadiotis A&A, 686 (2024) L10 Published online: 04 June 2024 DOI: 10.1051/0004-6361/202450217