New horizons for extreme light physics with mega-science project XCELS A.V. Bashinov, A.A. Gonoskov, A.V. Kim, G. Mourou and A.M. Sergeev Eur. Phys. J. Special Topics, 223 6 (2014) 1105-1112 Published online: 04 June 2014 DOI: 10.1140/epjst/e2014-02161-7