Scaled protogalactic magnetic field generation in laser-produced shock waves G. Gregori, 1, 2 A. Ravasio, 3 C. D. Murphy, 1 K. Schaar, 1 A. Baird, 1 A. R. Bell, 1 A. Benuzzi-Mounaix, 3 R. Bingham, 2 C. Constantin, 4 R. P. Drake, 5 M. Edwards, 1 E. T. Everson, 4 C. D. Gregory, 6 Y. Kuramitsu, 7 W. Lau, 1 J. Mithen, 1 C. Niemann, 4 H.-S. Park, 8 B. A. Remington, 8 B. Reville, 1 A. P. L. Robinson, 2 D. D. Ryutov, 8 Y. Sakawa, 7 S. Yang, 1 N. C. Woolsey, 6 M. Koenig, 3 and F. Miniati 9 1 Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK 2 Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, UK 3 Laboratoire pour l’Utilisation de Lasers Intenses, UMR7605, CNRS CEA, Universit´ e Paris VI Ecole Polytechnique, 91128 Palaiseau Cedex, France 4 University of California Los Angeles, Los Angeles, CA 90095, USA 5 Atmospheric, Oceanic, Space Science, University of Michigan, 2455 Hayward St, Ann Arbor, MI 48103, USA 6 Department of Physics, Heslington, University of York, YO10 5DD, UK 7 Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871, Japan 8 Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551, USA 9 Physics Department, Wolfgang-Pauli-Strasse 27, ETH-Z¨ urich, CH-8093 Z¨ urich, Switzerland 1