Wavelength-scale platinum wires were irradiated by a 1-micron wavelength laser at relativistic intensities, accelerating electrons in the laser-matter interaction. Wire diameters and angles relative to laser polarization were varied, and emitted electron distributions were measured. (C) 2014 Optical Society of America

Overview of the laser systems being built for ELI-Beamlines is presented. The facility will make available high-brightness multi-TW ultrashort laser pulses at kHz repetition rate, PW 10 Hz repetition rate pulses, and kilojoule nanosecond pulses for generation of 10 PW peak power. The lasers will extensively employ the emerging technology of diode-pumped solid state lasers (DPSSL) to pump OPCPA and Ti: sapphire broadband amplifiers. These systems will provide the user community with cutting-edge laser resources for programmatic research in generation and applications of high-intensity X-ray sources, in particle acceleration, and in dense-plasma and high-field physics.

Explosions of methane clusters using 38 nm XUV laser pulses were udicd. Ion fragmentation dynamics depends upon cluster size. Coulomb explosion of protons followed by recombination of methane fragments has been observed.

We report results of new pair creation experiments using similar to 100 Joule pulses of the Texas Petawatt Laser to irradiate solid gold and platinum targets, with intensities up to similar to 1.9 x 10(21) W.cm(-2) and pulse durations as short as similar to 130 fs. Positron to electron (e+/e-) ratios >15% were observed for many thick disk and rod targets, with the highest e+/e- ratio reaching similar to 50% for a Pt rod. The inferred pair yield was similar to few x 10(10) with emerging pair density reaching similar to 10(15)/cm(3) so that the pair skin depth becomes < pair jet transverse size. These results represent major milestones towards the goal of creating a significant quantity of dense pair-dominated plasmas with e+/e- approaching 100% and pair skin depth << pair plasma size, which will have wide-ranging applications to astrophysics and fundamental physics.

We have designed and assembled an experiment to evaluate the role of continuum lowering in XUV nanocluster ionization. Metal oxide nanoparticles, generated via laser ablation of microparticles, will be irradiated by intense coherent XUV pulses.

We report preliminary results on the stability of a magnetized laser-launched blast wave scaled to simulate a supernova remnant. Magnetic fields appear to suppress the Vishniac overstability at high mode numbers, possibly facilitating gravitational star formation.

At the Texas Petawatt laser facility we developed a novel ultra-short pulsed laser-driven neutron source generating an unprecedented output peak flux. Our results show a dramatic onset of high-energy electron generation from petawatt laser-irradiated plastic targets for targets thinner than a few microns. In this regime, the copious amounts of multi-MeV electrons emitted from the target are utilized to generate photo-neutrons from a metal converter. The neutrons are generated with a < 50 ps pulse duration and a flux of 10(18) n/cm(2)/s, exceeding any other pulsed or CW neutron source. In this paper, we will report on our measurement of the neutron yields produced from high atomic number converters.

To measure relativistic laser hole boring velocities up to 0.18c, an ultra-broadband diagnostic capable of retrieving the full time resolved pulse phase is required. The design of such a device based on GRENOUILLE is presented.