We present a methodology for conducting the design calculations for fast ignition indirect-drive implosions with an embedded cone for introducing a second laser beam to ignite the compressed fuel. These calculations are tuned to achieve several design goals. We demonstrate a major feature of the implosion simulations, the lagging of the implosions along the cone. Possible avenues for enhancing the coupling of the fast electrons to the dense compressed DT fuel are discussed.

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DOE OSTI2012

Characterizing counter-streaming interpenetrating plasmas relevant to astrophysical collisionless shocks

A series of Omega experiments have produced and characterized high velocity counter-streaming plasma flows relevant for the creation of collisionless shocks. Single and double CH{sub 2} foils have been irradiated with a laser intensity of {approx} 10{sup 16} W/cm{sup 2}. The laser ablated plasma was characterized 4 mm from the foil surface using Thomson scattering. A peak plasma flow velocity of 2000 km/s, an electron temperature of {approx} 110 eV, an ion temperature of {approx} 30 eV, and a density of {approx} 10{sup 18} cm{sup -3} were measured in the single foil configuration. Significant increases in electron and ion temperatures were seen in the double foil geometry. The measured single foil plasma conditions were used to calculate the ion skin depth, c/{omega}{sub pi}{approx}0.16 mm, the interaction length, Script-Small-L {sub int}, of {approx} 8 mm, and the Coulomb mean free path, {lambda}{sub mfp}{approx}27mm. With c/{omega}{sub pi} Much-Less-Than Script-Small-L {sub int} Much-Less-Than {lambda}{sub mfp}, we are in a regime where collisionless shock formation is possible.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

DOE OSTI2012

Stauts of the Laser Inertial Fusion Energy (LIFE) Hohlraum Point Design

Progress on the hohlraum point design for the LIFE engine is described. New features in the original design [Amendt et al., Fus. Sci. Technol. 60, 49 (2011)] are incorporated that address the imperatives of low target cost, high manufacturing throughput, efficient and prompt material recycling, an ability for near-term testing of key target design uncertainties on the National Ignition Facility, and robustness to target chamber environment and injection insults. To this end, the novel use of Pb hohlraums and aerogel-supported liquid DT fuel loading within a high-density-carbon (HDC) ablator is implemented in the hohlraum point design.

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DOE OSTI2011

Characterizing counter-streaming interpenetrating plasmas relevant to astrophysical collisionless shocks

Abstract not provided

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DOE OSTI2011

Progress and prospects for an FI relevant point design

The physics issues involved in scaling from sub ignition to high gain fast ignition are discussed. Successful point designs must collimate the electrons and minimize the stand off distance to avoid multi mega-joule ignition energies. Collimating B field configurations are identified and some initial designs are explored.

42 ENGINEERING↗

DOE OSTI2011

Ignition Capsules with Aerogel-Supported Liquid DT Fuel For The National Ignition Facility

For high repetition-rate fusion power plant applications, capsules with aerogel-supported liquid DT fuel can have much reduced fill time compared to {beta}-layering a solid DT fuel layer. The melting point of liquid DT can be lowered once liquid DT is embedded in an aerogel matrix, and the DT vapor density is consequently closer to the desired density for optimal capsule design requirement. We present design for NIF-scale aerogel-filled capsules based on 1-D and 2-D simulations. An optimal configuration is obtained when the outer radius is increased until the clean fuel fraction is within 65-75% at peak velocity. A scan (in ablator and fuel thickness parameter space) is used to optimize the capsule configurations. The optimized aerogel-filled capsule has good low-mode robustness and acceptable high-mode mix.

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DOE OSTI2011

A1.5 Fusion Performance

Analysis and radiation hydrodynamics simulations for expected high-gain fusion target performance on a demonstration 1-GWe Laser Inertial Fusion Energy (LIFE) power plant in the mid-2030s timeframe are presented. The required laser energy driver is 2.2 MJ at a 0.351-{micro}m wavelength, and a fusion target gain greater than 60 at a repetition rate of 16 Hz is the design goal for economic and commercial attractiveness. A scaling-law analysis is developed to benchmark the design parameter space for hohlraum-driven central hot-spot ignition. A suite of integrated hohlraum simulations is presented to test the modeling assumptions and provide a basis for a near-term experimental resolution of the key physics uncertainties on the National Ignition Facility (NIF). The NIF is poised to demonstrate ignition by 2012 based on the central hot spot (CHS) mode of ignition and propagating thermonuclear burn [1]. This immediate prospect underscores the imperative and timeliness of advancing inertial fusion as a carbon-free, virtually limitless source of energy by the mid-21st century to substantially offset fossil fuel technologies. To this end, an intensive effort is underway to leverage success at the NIF and to provide the foundations for a prototype 'LIFE.1' engineering test facility by {approx}2025, followed by a commercially viable 'LIFE.2' demonstration power plant operating at 1 GWe by {approx}2035. The current design goal for LIFE.2 is to accommodate {approx}2.2 MJ of laser energy (entering the high-Z radiation enclosure or 'hohlraum') at a 0.351-{micro}m wavelength operating at a repetition rate of 16 Hz and to provide a fusion target yield of 132 MJ. To achieve this design goal first requires a '0-d' analytic gain model that allows convenient exploration of parameter space and target optimization. This step is then followed by 2- and 3-dimensional radiation-hydrodynamics simulations that incorporate laser beam transport, x-ray radiation transport, atomic physics, and thermonuclear burn [2]. These simulations form the basis for assessing the susceptibility to hydrodynamic instability growth, target performance margins, laser backscatter induced by plasma density fluctuations within the hohlraum, and the threat spectrum emerging from the igniting capsule, e.g., spectra, fluences and anisotropy of the x rays and ions, for input into the chamber survivability calculations. The simulations follow the guidelines of a 'point design' methodology, which formally designates a well-defined milestone in concept development that meets established criteria for experimental testing. In Section 2, the 0-d analytic gain model to survey gain versus laser energy parameter space is discussed. Section 3 looks at the status of integrated hohlraum simulations and the needed improvements in laser-hohlraum coupling efficiency to meet the LIFE.2 threshold (net) target gain of {approx}60. Section 4 considers advanced hohlraum designs to well exceed the LIFE.2 design goal for satisfactory performance margins. We summarize in Sec. 5.

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