1. Centre Lasers Intenses et Applications, UMR 5107 1 , 351 Cours de la libération, 33400 Talence, France
2. Laboratory for Laser Energetics 2 , 250 East River Rd., Rochester, New York 14623-1212, USA
3. Los Alamos National Laboratory 3 , Los Alamos, New Mexico 87545, USA