Z-beamlet (ZBL) multi-frame back-lighter (MFB) system for ICF/plasma diagnostics

Z-Beamlet [1] is a single-beam high-energy Nd:glass laser used for backlighting high energy density (HED) plasma physics experiments at Sandia's Z-accelerator facility. The system currently generates a single backlit image per experiment, and has been employed on approximately 50% of Z-accelerator system shots in recent years. We have designed and are currently building a system that uses Z-Beamlet to generate two distinct backlit images with adjustable time delay ranging from 2 to 20 ns between frames. The new system will double the rate of data collection and allow the temporal evolution of high energy density phenomena to be recorded on a single shot

Cryogenic target development for fast ignition with Z-pinch-driven fuel assembly

We are developing an alternative approach to indirect-drive fast ignition fusion targets in which a liquid cryogenic fuel layer is condensed in situ from a low pressure external gas supply and confined between a thick outer ablator shell and a thin inner shell. The shape and surface quality of the liquid fuel layer is determined entirely by the characteristics of the bounding shells. Liquid fuel targets of this type have a number of potential advantages including greatly reduced temperature control requirements and drastically reduced cost and complexity of the cryogenic support system compared to $\beta$-layed DT targets. This liquid fuel concept is particularly appropriate for a hemispherical capsule configuration with single-sided x-ray drive by a z-pinch source. Technology issues for concentric-shell liquid cryogenic target development and progress in thin inner hemispherical shell fabrication are discussed

Recent Experimental Results and Modelling of High-Mach-Number Jets and the Transition to Turbulence

In recent years, we have carried out experiments at the University of Rochester’s Omega laser in which supersonic, dense-plasma jets are formed by the interaction of strong shocks in a complex target assembly (Foster et al., Phys. Plasmas 9 (2002) 2251). We describe recent, significant extensions to this work, in which we consider scaling of the experiment, the transition to turbulence, and astrophysical analogues. In new work at the Omega laser, we are developing an experiment in which a jet is formed by laser ablation of a titanium foil mounted over a titanium washer with a central, cylindrical hole. Some of the resulting shocked titanium expands, cools, and accelerates through the vacuum region (the hole in the washer) and then enters a cylinder of low-density foam as a jet. We discuss the design of this new experiment and present preliminary experimental data and results of simulations using AWE hydrocodes. In each case, the high Reynolds number of the jet suggests that turbulence should develop, although this behaviour cannot be reliably modelled by present, resolution-limited simulations (because of their low-numerical Reynolds number).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42047/1/10509_2005_Article_3921.pd