Creation of ultra-high energy density matter using nanostructured targets on Titan laser

J. PARK; R. TOMMASINI; R. LONDON; J.J. ROCCA; R.C. HOLLINGER; C. BARGSTEN; V. SHLYAPTSEV; H. CHEN; A. PUKHOV; M.G. CAPELUTO; M. HILL

California

Simposio; National Ignition Facility (NIF) and Jupiter Laser Facility (JLF) User Group Meeting 2016; 2016

Recent experiments have demonstrated that trapping of 60 femtosecond laser pulses of relativistic intensity deep within ordered nanowire arrays can create a new ultra-hot plasma regime. Here we report on the experiments at the Titan laser at the Lawrence Livermore National Laboratory that aim to scale these results by two orders of magnitude in laser energy. Preliminary analysis of the Titan results show that sub-picosecond laser irradiation of vertically aligned nanostructures of Au, Ag and Ni produces an increase of a factor greater than 1.6 in the suprathermal electron temperatures and an increase by a factor of 3 in the conversion efficiency into continuum x-rays, both with respect to flat targets of the same composition. Kalpha radiation from nanowire array targets also shows an increase between 3x and 5x over flat targets. The nanowire array targets reflected a 5x smaller fraction of the laser energy, indicating significantly larger absorption of the laser pulse.