High-intensity laser-plasma interaction with wedge-shaped-cavity targets

High-intensity, short-pulse laser-interaction experiments with small-mass, wedge-shaped-cavity Cu targets are presented. The diagnostics provided spatially and spectrally resolved measurements of the Cu K-alpha line emission at 8 keV. The conversion efficiency of short-pulse laser energy into fast electrons was inferred from the x-ray yield for wedge opening angles between 30 and 60 and for s- and p-polarized laser irradiation. Up to 36 +/- 7% conversion efficiency was measured for the narrowest wedge with p-polarization. The results are compared with predictions from two-dimensional particle-in-cell simulations. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3484217]