1. Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
2. Instituto de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago, Chile
3. Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
4. Laboratoire pour l’Utilisation de Lasers Intenses, CNRS CEA, Ecole Polytechnique, 91128 Palaiseau Cedex, France
5. Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow 125412, Russia
6. Université de Bordeaux-CNRS-CEA, CELIA, UMR 5107, F-33405 Talence, France