1. Centre Lasers Intenses et Applications (CELIA), UMR 5107, Université de Bordeaux-CNRS-CEA, F-33405 Talence, France
2. Departamento de Física Teórica Atómica y Óptica, Universidad de Valladolid, 47011 Valladolid, Spain
3. European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
4. Laboratory for Laser Energetics, 250 East River Road, Rochester, New York 14623, USA
5. Department of Astrophysics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
6. Center for Energy Research, University of California San Diego, La Jolla, California 92093, USA
7. Extreme Light Infrastructure—Nuclear Physics, 077125 Bucharest-Magurele, Romania
8. CEA-CESTA, 15 avenue des Sablières, CS 60001, 33116 Le Barp Cedex, France