Progress in fast ignitor research with the Nova petawatt laser facility

The physics of fast ignition is being studied using a petawatt laser facility at the Lawrence Livermore National Laboratory. Performance of the PW laser with deformable mirror wavefront control giving intensities up to 3x10{sup 20} Wcm{sup {minus}2} is described. Measurements of the efficiency of conversion of laser energy to relativistic electrons and of their energy spectrum and angular distribution including an observed narrow beam angle of {+-}15{degree}, are reported. Heating by the electrons to near 1keV in solid density CD{sub 2} is inferred from the thermo-nuclear neutron yield. Estimates suggest an optimized gain of 300x if the National Ignition Facility were to be adapted for fast ignition.