1. High Energy Density Science Division, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
2. Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, California 94025, USA
3. Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544, USA
4. International Research Collaboration Center, National Institute of Natural Sciences, Tokyo 105-0001, Japan
5. Department of Earth and Planetary Science, University of Tokyo, Tokyo 113-0033, Japan
6. Department of Physics, Stanford University, Stanford, California 94305, USA
7. SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA