Coherent acceleration by laser pulse echelons in periodic plasma structures A. Pukhov, I. Kostyukov, T. Tückmantel, Ph. Luu-Thanh and G. Mourou Eur. Phys. J. Special Topics, 223 6 (2014) 1197-1206 Published online: 04 June 2014 DOI: 10.1140/epjst/e2014-02173-3