The evolution of two-dimensional effects in fast-electron transport from high-intensity laser-plasma interactions

Measurements of local and remote energy deposition by fast electrons have been made in 1.3 μm and 1.05 μm laser irradiation experiments with plane targets and various pulse lengths. From optical and x-ray streak photography and spatially resolved Kα yield measurements it is found that up to 30% of the absorbed laser energy spreads laterally to distances of several millimetres from the focal spot with a spreading velocity in excess of 108 cm s-1. (author)