D Kumar (ELI Beamlines), M Šmíd (ELI Beamlines), S Singh (ELI Beamlines), A Soloviev (Institute of Applied Physics of the Russian Academy of Sciences (IAP RAS)), H Bohlin (ELI Beamlines), K Burdonov (Institute of Applied Physics of the Russian Academy of Sciences (IAP RAS)), G Fente (ELI Beamlines), A Kotov (Institute of Applied Physics of the Russian Academy of Sciences (IAP RAS)), L Lancia (LULI—CNRS), V Lédl (Research Center Toptec), S Makarov (Joint Institute for High Temperatures Russian Academy of Science (JIHT RAS)), M Morrissey (ELI Beamlines), S Perevalov (Institute of Applied Physics of the Russian Academy of Sciences (IAP RAS)), D Romanovsky (Institute of Applied Physics of the Russian Academy of Sciences (IAP RAS)), S Pikuz (Joint Institute for High Temperatures Russian Academy of Science (JIHT RAS)), R Kodama (Division of Electrical), D Neely (STFC Rutherford Appleton Lab.), P McKenna (Cockcroft Inst., and Strathclyde Univ.), T Laštovička (ELI Beamlines), M Starodubtsev (Institute of Applied Physics of the Russian Academy of Sciences (IAP RAS)), S Weber (ELI Beamlines), M Nakatsutsumi (European XFEL GmbH), J Fuchs (LULI—CNRS)