Collimation of Fast Electrons in Critical Density Plasma Channel

Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan 1)LULI, CNRS -Ecole Polytechnique -Universite Pierre et Marie Curie -CEA, 91128 Palaiseau, France 2)European X-Ray Free-Electron Laser Facility (XFEL) GmbH, Germany 3)CEA, DAM, DIF, F-91297 Arpajon, France 4)La SAPIENZA, University of Rome, Dip. SBAI, 00161 Rome, Italy 5)School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9ST, Scotland, UK