Scope of Work for Integration Management and Installation Services of the National Ignition Facility Beampath Infrastructure System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coyle, P.D.

2000-04-25

The goal of the National Ignition Facility (NIF) project is to provide an aboveground experimental capability for maintaining nuclear competence and weapons effects simulation and to provide a facility capable of achieving fusion ignition using solid-state lasers as the energy driver. The facility will incorporate 192 laser beams, which will be focused onto a small target located at the center of a spherical target chamber--the energy from the laser beams will be deposited in a few billionths of a second. The target will then implode, forcing atomic nuclei to sufficiently high temperatures and densities necessary to achieve a miniature fusionmore » reaction. The NIF is under construction, at Livermore, California, located approximately 50 miles southeast of San Francisco, California.« less

Scope of Work for Integration Management and Installation Services of the National Ignition Facility Beampath Infrastructure System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coyle, P.D.

The goal of the National Ignition Facility (NIF) project is to provide an aboveground experimental capability for maintaining nuclear competence and weapons effects simulation and to provide a facility capable of achieving fusion ignition using solid-state lasers as the energy driver. The facility will incorporate 192 laser beams, which will be focused onto a small target located at the center of a spherical target chamber--the energy from the laser beams will be deposited in a few billionths of a second. The target will then implode, forcing atomic nuclei to sufficiently high temperatures and densities necessary to achieve a miniature fusionmore » reaction. The NIF is under construction, at Livermore, California, located approximately 50 miles southeast of San Francisco, California.« less

Effect of freeze-drying and self-ignition process on the microstructural and electrochemical properties of Li{sub 4}Ti{sub 5}O{sub 12}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jamin, Claire; Traina, Karl; APTIS, Department of Physics, B5a, University of Liège, Sart-Tilman, 4000 Liège

2013-11-15

Graphical abstract: - Highlights: • Li{sub 4}Ti{sub 5}O{sub 12} is prepared by a method involving self-ignition of a freeze-dried gel. • Addition of NH{sub 4}NO{sub 3} modifies the self-ignition propagation mode. • Well-crystallized Li{sub 4}Ti{sub 5}O{sub 12} phase is obtained after only 2 h at 800 °C. • Li{sub 4}Ti{sub 5}O{sub 12} powder has 161 mAh g{sup −1} capacity and good retention at C/4 rate. - Abstract: Crystalline Li{sub 4}Ti{sub 5}O{sub 12} is synthesized by a method involving the freeze-drying and self-ignition of a gel prepared from titanium isopropoxide, lithium nitrate and hydroxypropylmethylcellulose (HPMC). This synthesis route yields crystalline Li{submore » 4}Ti{sub 5}O{sub 12} particles after calcination at 800 °C for 2 h. In an alternative route, addition of ammonium nitrate shifts the self-ignition mode from wave-like propagation to simultaneous. Powders with different microstructures are thereby obtained. Electrochemical characterization shows that the best results for Li{sup +} intercalation/desintercalation are obtained for the powder prepared without ammonium nitrate addition. These results highlight the necessity for a control of the self-ignition mode to obtain adequate properties.« less

Eight cm technology thruster development. [structurally integrated ion thruster for attitude control and stationkeeping of synchronous satellites

NASA Technical Reports Server (NTRS)

Hyman, J., Jr.

1974-01-01

A structural integrated ion thruster with 8-cm beam diameter (SIT-8) was developed for attitude control and stationkeeping of synchronous satellites. As optimized, the system demonstrates a thrust T=1.14 mlb (not corrected for beam V sub B = 1200 V (I sub sp = 2200 sec) total propellant utilization efficiency nu sub u = 59.8% (is approximately 72% without auxiliary pulse-igniter electrode), and electrical efficiency n sub E 61.9%. The thruster incorporates a wire-mesh anode and tantalum cover surfaces to control discharge chamber flake formation and employs an auxiliary pulse-igniter electrode for hollow-cathode ignition. When the SIT-8 is integrated with the compatible SIT-5 propellant tankage, the system envelope is 35 cm long by 13 cm flange bolt circle with a mass of 9.8 kg including 6.8 kg of mercury propellant. Two thrust vectoring systems which generate beam deflections in two orthogonal directions were also developed under the program and tested with the 8-cm thruster. One system vectors the beam over + or - 10 degrees by gimbaling of the entire thruster (not including tankage), while the other system vectors the beam over + or - 7 degrees by translating the accel electrode relative to the screen electrode.

Cryogenic target system for hydrogen layering

DOE PAGES

Parham, T.; Kozioziemski, B.; Atkinson, D.; ...

2015-11-24

Here, a cryogenic target positioning system was designed and installed on the National Ignition Facility (NIF) target chamber. This instrument incorporates the ability to fill, form, and characterize the NIF targets with hydrogen isotopes needed for ignition experiments inside the NIF target bay then transport and position them in the target chamber. This effort brought to fruition years of research in growing and metrologizing high-quality hydrogen fuel layers and landed it in an especially demanding operations environment in the NIF facility. D-T (deuterium-tritium) layers for NIF ignition experiments have extremely tight specifications and must be grown in a very highlymore » constrained environment: a NIF ignition target inside a cryogenic target positioner inside the NIF target bay. Exquisite control of temperature, pressure, contaminant level, and thermal uniformity are necessary throughout seed formation and layer growth to create an essentially-groove-free single crystal layer.« less

The national ignition facility: Path to ignition in the laboratory

NASA Astrophysics Data System (ADS)

Moses, E. I.; Bonanno, R. E.; Haynam, C. A.; Kauffman, R. L.; MacGowan, B. J.; Patterson, R. W., Jr.; Sawicki, R. H.; van Wonterghem, B. M.

2006-06-01

The National Ignition Facility (NIF) is a 192-beam laser facility presently under construction at LLNL. When completed, NIF will be a 1.8-MJ, 500-TW ultraviolet laser system. Its missions are to obtain fusion ignition and to perform high energy density experiments in support of the U.S. nuclear weapons stockpile. Four of the NIF beams have been commissioned to demonstrate laser performance and to commission the target area including target and beam alignment and laser timing. During this time, NIF demonstrated on a single-beam basis that it will meet its performance goals and demonstrated its precision and flexibility for pulse shaping, pointing, timing and beam conditioning. It also performed four important experiments for Inertial Confinement Fusion and High Energy Density Science. Presently, the project is installing production hardware to complete the project in 2009 with the goal to begin ignition experiments in 2010. An integrated plan has been developed including the NIF operations, user equipment such as diagnostics and cryogenic target capability, and experiments and calculations to meet this goal. This talk will provide NIF status, the plan to complete NIF, and the path to ignition.

The National Ignition Facility: The Path to a Carbon-Free Energy Future

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stolz, C J

2011-03-16

The National Ignition Facility (NIF), the world's largest and most energetic laser system, is now operational at Lawrence Livermore National Laboratory (LLNL). The NIF will enable exploration of scientific problems in national strategic security, basic science and fusion energy. One of the early NIF goals centers on achieving laboratory-scale thermonuclear ignition and energy gain, demonstrating the feasibility of laser fusion as a viable source of clean, carbon-free energy. This talk will discuss the precision technology and engineering challenges of building the NIF and those we must overcome to make fusion energy a commercial reality.

The National Ignition Facility: the path to a carbon-free energy future.

PubMed

Stolz, Christopher J

2012-08-28

The National Ignition Facility (NIF), the world's largest and most energetic laser system, is now operational at Lawrence Livermore National Laboratory. The NIF will enable exploration of scientific problems in national strategic security, basic science and fusion energy. One of the early NIF goals centres on achieving laboratory-scale thermonuclear ignition and energy gain, demonstrating the feasibility of laser fusion as a viable source of clean, carbon-free energy. This talk will discuss the precision technology and engineering challenges of building the NIF and those we must overcome to make fusion energy a commercial reality.

The potential of imposed magnetic fields for enhancing ignition probability and fusion energy yield in indirect-drive inertial confinement fusion

NASA Astrophysics Data System (ADS)

Perkins, L. J.; Ho, D. D.-M.; Logan, B. G.; Zimmerman, G. B.; Rhodes, M. A.; Strozzi, D. J.; Blackfield, D. T.; Hawkins, S. A.

2017-06-01

We examine the potential that imposed magnetic fields of tens of Tesla that increase to greater than 10 kT (100 MGauss) under implosion compression may relax the conditions required for ignition and propagating burn in indirect-drive inertial confinement fusion (ICF) targets. This may allow the attainment of ignition, or at least significant fusion energy yields, in presently performing ICF targets on the National Ignition Facility (NIF) that today are sub-marginal for thermonuclear burn through adverse hydrodynamic conditions at stagnation [Doeppner et al., Phys. Rev. Lett. 115, 055001 (2015)]. Results of detailed two-dimensional radiation-hydrodynamic-burn simulations applied to NIF capsule implosions with low-mode shape perturbations and residual kinetic energy loss indicate that such compressed fields may increase the probability for ignition through range reduction of fusion alpha particles, suppression of electron heat conduction, and potential stabilization of higher-mode Rayleigh-Taylor instabilities. Optimum initial applied fields are found to be around 50 T. Given that the full plasma structure at capsule stagnation may be governed by three-dimensional resistive magneto-hydrodynamics, the formation of closed magnetic field lines might further augment ignition prospects. Experiments are now required to further assess the potential of applied magnetic fields to ICF ignition and burn on NIF.

Ignition Characterization Test Results for the LO2/Ethanol Propellant Combination

NASA Technical Reports Server (NTRS)

Popp, Christopher G.; Robinson, Phillip J.; Veith, Eric M.

2006-01-01

A series of contracts were issued by the Marshall Space Flight Center (MSFC) of the National Aeronautics and Space Administration (NASA) under the auspices of the Exploration Systems Mission Directorate to develop and expand the maturity of candidate technologies considered to be important for future space exploration. One such technology was to determine the viability of incorporating non-toxic propellants for Reaction Control Subsystems (RCS). Contract NAS8-01109 was issued to Aerojet to develop a dual thrust Reaction Control Engine (RCE) that utilized liquid oxygen and ethanol as the propellants. The dual thrust RCE incorporated a primary thrust level of 870 lbf, and a vernier thrust level of 10 - 30 lbf. The preferred RCS approach for the dual thrust RCE was to utilize pressure-fed liquid oxygen (LOX) and ethanol propellants; however, previous dual thrust feasibility testing incorporated GOX/Ethanol igniters as opposed to LOX/Ethanol igniters in the design. GOX/Ethanol was easier to ignite, but this combination had system design implications of providing GOX for the igniters. A LOX/Ethanol igniter was desired; however, extensive LOX/Ethanol ignition data over the anticipated operating range for the dual thrust RCE did not exist. Therefore, Aerojet designed and tested a workhorse LOX igniter to determine LOX/Ethanol ignition characteristics as part of a risk mitigation effort for the dual thrust RCE design. LOX, encompassing potential two-phase flow conditions anticipated being present in real mission applications. A workhorse igniter was designed to accommodate the hll LOX design flowrate, as well as a reduced GOX flowrate. It was reasoned that the initial LOX flow through the igniter would flash to GOX due to the latent heat stored in the hardware, causing a reduced oxygen flowrate because of a choked, or sonic, flow condition through the injection elements. As LOX flow continued, the hardware would chill-in, with the injected oxygen flow transitioning from cold GOX through two-phase flow to subcooled LOX. permitted oxygen state points to be determined in the igniter oxidizer manifold, and gas-side igniter chamber thermocouples provided chamber thermal profile characteristics. The cold flow chamber pressure (P(sub c)) for each test was determined and coupled with the igniter chamber diameter (D(sub c)) to calculate the characteristic quench parameter (P(sub c) x D(sub c)), which was plotted as a function of core mixture ratio, m. Ignition limits were determined over a broad range of valve inlet conditions, and ignition was demonstrated with oxygen inlet conditions that ranged from subcooled 210 R LOX to 486 R GOX. Once ignited at cold GOX conditions, combustion was continuous as the hardware chilled in and the core mixture ratio transitioned from values near 1.0 to over 12.5. Pulsing is required in typical RCS engines; therefore, the workhorse igniter was pulse tested to verify the ability to provide the required ignition for a pulsing RCE. The minimum electrical pulse width (EPW) of the dual thrust RCE was 0.080 seconds.

National Ignition Facility project acquisition plan revision 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clobes, A.R.

The purpose of this National Ignition Facility Acquisition Plan is to describe the overall procurement strategy planned for the National Ignition Facility M Project. It was prepared for the NIP Prood Office by the NIF Procurement Manager.

A measurable Lawson criterion and hydro-equivalent curves for inertial confinement fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, C. D.; Betti, R.; Departments of Mechanical Engineering and Physics and Astronomy, University of Rochester, Rochester, New York 14623

2008-10-15

It is shown that the ignition condition (Lawson criterion) for inertial confinement fusion (ICF) can be cast in a form dependent on the only two parameters of the compressed fuel assembly that can be measured with existing techniques: the hot spot ion temperature (T{sub i}{sup h}) and the total areal density ({rho}R{sub tot}), which includes the cold shell contribution. A marginal ignition curve is derived in the {rho}R{sub tot}, T{sub i}{sup h} plane and current implosion experiments are compared with the ignition curve. On this plane, hydrodynamic equivalent curves show how a given implosion would perform with respect to themore » ignition condition when scaled up in the laser-driver energy. For 3<{sub n}<6 keV, an approximate form of the ignition condition (typical of laser-driven ICF) is {sub n}{sup 2.6}{center_dot}<{rho}R{sub tot}>{sub n}>50 keV{sup 2.6}{center_dot} g/cm{sup 2}, where <{rho}R{sub tot}>{sub n} and {sub n} are the burn-averaged total areal density and hot spot ion temperature, respectively. Both quantities are calculated without accounting for the alpha-particle energy deposition. Such a criterion can be used to determine how surrogate D{sub 2} and subignited DT target implosions perform with respect to the one-dimensional ignition threshold.« less

Effect of flow velocity and temperature on ignition characteristics in laser ignition of natural gas and air mixtures

NASA Astrophysics Data System (ADS)

Griffiths, J.; Riley, M. J. W.; Borman, A.; Dowding, C.; Kirk, A.; Bickerton, R.

2015-03-01

Laser induced spark ignition offers the potential for greater reliability and consistency in ignition of lean air/fuel mixtures. This increased reliability is essential for the application of gas turbines as primary or secondary reserve energy sources in smart grid systems, enabling the integration of renewable energy sources whose output is prone to fluctuation over time. This work details a study into the effect of flow velocity and temperature on minimum ignition energies in laser-induced spark ignition in an atmospheric combustion test rig, representative of a sub 15 MW industrial gas turbine (Siemens Industrial Turbomachinery Ltd., Lincoln, UK). Determination of minimum ignition energies required for a range of temperatures and flow velocities is essential for establishing an operating window in which laser-induced spark ignition can operate under realistic, engine-like start conditions. Ignition of a natural gas and air mixture at atmospheric pressure was conducted using a laser ignition system utilizing a Q-switched Nd:YAG laser source operating at 532 nm wavelength and 4 ns pulse length. Analysis of the influence of flow velocity and temperature on ignition characteristics is presented in terms of required photon flux density, a useful parameter to consider during the development laser ignition systems.

Laser Induced Aluminum Surface Breakdown Model

NASA Technical Reports Server (NTRS)

Chen, Yen-Sen; Liu, Jiwen; Zhang, Sijun; Wang, Ten-See (Technical Monitor)

2002-01-01

Laser powered propulsion systems involve complex fluid dynamics, thermodynamics and radiative transfer processes. Based on an unstructured grid, pressure-based computational aerothermodynamics; platform, several sub-models describing such underlying physics as laser ray tracing and focusing, thermal non-equilibrium, plasma radiation and air spark ignition have been developed. This proposed work shall extend the numerical platform and existing sub-models to include the aluminum wall surface Inverse Bremsstrahlung (IB) effect from which surface ablation and free-electron generation can be initiated without relying on the air spark ignition sub-model. The following tasks will be performed to accomplish the research objectives.

Numerical Simulation of Ground Coupling of Low Yield Nuclear Detonation

DTIC Science & Technology

2010-06-01

Without nuclear testing, advanced simulation and experimental facilities, such as the National Ignition Facility ( NIF ), are essential to assuring...in planning future experimental work at NIF . 15. NUMBER OF PAGES 93 14. SUBJECT TERMS National Ignition Facility, GEODYN, Ground Coupling...simulation and experimental facilities, such as the National Ignition Facility ( NIF ), are essential to assuring safety, reliability, and effectiveness

CHEMICAL ENGINEERING DIVISION SUMMARY REPORT, OCTOBER, NOVEMBER, DECEMBER 1960

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1961-03-01

Chemical-metallurgical processing studies were made of pyrometallurgical development snd research, and fuel processing facilities for EBR-II. Fuel-cycle applications of fluidization and volatility techniques included laboratory investigations of fluoride volatility processes, engineeringscale development, and conversion of UF/sub 6/ to UO/sub 2/. Reactor safety studies consisted of metal oxidation and ignition kinetics, and metal-water reactions. Reactor chemistry investigations were conducted to determine nuclear constants and suitable reactor decontamination methods. Routine operations are summarized for the high-level gammairradiation facillty and waste processing. (B.O.G.)

National Ignition Facility main laser stray light analysis and control

DOE Office of Scientific and Technical Information (OSTI.GOV)

English, R E; Miller, J L; Peterson, G

1998-06-26

Stray light analysis has been carried out for the main laser section of the National Ignition Facility main laser section using a comprehensive non-sequential ray trace model supplemented with additional ray trace and diffraction propagation modeling. This paper describes the analysis and control methodology, gives examples of ghost paths and required tilted lenses, baffles, absorbers, and beam dumps, and discusses analysis of stray light "pencil beams" in the system.

Very Low Thrust Gaseous Oxygen-hydrogen Rocket Engine Ignition Technology

NASA Technical Reports Server (NTRS)

Bjorklund, Roy A.

1983-01-01

An experimental program was performed to determine the minimum energy per spark for reliable and repeatable ignition of gaseous oxygen (GO2) and gaseous hydrogen (GH2) in very low thrust 0.44 to 2.22-N (0.10 to 0.50-lb sub f) rocket engines or spacecraft and satellite attitude control systems (ACS) application. Initially, the testing was conducted at ambient conditions, with the results subsequently verified under vacuum conditions. An experimental breadboard electrical exciter that delivered 0.2 to 0.3 mj per spark was developed and demonstrated by repeated ignitions of a 2.22-N (0.50-lb sub f) thruster in a vacuum chamber with test durations up to 30 min.

A polar-drive shock-ignition design for the National Ignition Facilitya)

NASA Astrophysics Data System (ADS)

Anderson, K. S.; Betti, R.; McKenty, P. W.; Collins, T. J. B.; Hohenberger, M.; Theobald, W.; Craxton, R. S.; Delettrez, J. A.; Lafon, M.; Marozas, J. A.; Nora, R.; Skupsky, S.; Shvydky, A.

2013-05-01

Shock ignition [R. Betti et al., Phys. Rev. Lett. 98, 155001 (2007)] is being pursued as a viable option to achieve ignition on the National Ignition Facility (NIF). Shock-ignition target designs use a high-intensity laser spike at the end of a low-adiabat assembly pulse to launch a spherically convergent strong shock to ignite the hot spot of an imploding capsule. A shock-ignition target design for the NIF is presented. One-dimensional simulations indicate an ignition threshold factor of 4.1 with a gain of 58. A polar-drive beam-pointing configuration for shock-ignition experiments on the NIF at 750 kJ is proposed. The capsule design is shown to be robust to the various one- and two-dimensional effects and nonuniformities anticipated on the NIF. The target is predicted to ignite with a gain of 38 when including all anticipated levels of nonuniformity and system uncertainty.

Direct-drive inertial confinement fusion research at the Laboratory for Laser Energetics: charting the path to thermonuclear ignition

NASA Astrophysics Data System (ADS)

McCrory, R. L.; Regan, S. P.; Loucks, S. J.; Meyerhofer, D. D.; Skupsky, S.; Betti, R.; Boehly, T. R.; Craxton, R. S.; Collins, T. J. B.; Delettrez, J. A.; Edgell, D.; Epstein, R.; Fletcher, K. A.; Freeman, C.; Frenje, J. A.; Glebov, V. Yu.; Goncharov, V. N.; Harding, D. R.; Igumenshchev, I. V.; Keck, R. L.; Kilkenny, J. D.; Knauer, J. P.; Li, C. K.; Marciante, J.; Marozas, J. A.; Marshall, F. J.; Maximov, A. V.; McKenty, P. W.; Myatt, J.; Padalino, S.; Petrasso, R. D.; Radha, P. B.; Sangster, T. C.; Séguin, F. H.; Seka, W.; Smalyuk, V. A.; Soures, J. M.; Stoeckl, C.; Yaakobi, B.; Zuegel, J. D.

2005-10-01

Significant theoretical and experimental progress continues to be made at the University of Rochester's Laboratory for Laser Energetics (LLE), charting the path to direct-drive inertial confinement fusion (ICF) ignition. Direct drive offers the potential for higher-gain implosions than x-ray drive and is a leading candidate for an inertial fusion energy power plant. LLE's direct-drive ICF ignition target designs for the National Ignition Facility (NIF) are based on hot-spot ignition. A cryogenic target with a spherical DT-ice layer, within or without a foam matrix, enclosed by a thin plastic shell, will be directly irradiated with ~1.5 MJ of laser energy. Cryogenic and plastic/foam (surrogate-cryogenic) targets that are hydrodynamically scaled from these ignition target designs are imploded on the 60-beam, 30 kJ, UV OMEGA laser system to validate the key target physics issues, including energy coupling, hydrodynamic instabilities and implosion symmetry. Prospects for direct-drive ignition on the NIF are extremely favourable, even while it is in its x-ray-drive irradiation configuration, with the development of the polar-direct-drive concept. A high-energy petawatt capability is being constructed at LLE next to the existing 60-beam OMEGA compression facility. This OMEGA EP (extended performance) laser will add two short-pulse, 2.6 kJ beams to the OMEGA laser system to backlight direct-drive ICF implosions and study fast-ignition physics with focused intensities up to 6 × 1020 W cm-2.

National Ignition Facility under fire over ignition failure

NASA Astrophysics Data System (ADS)

Allen, Michael

2016-08-01

The 3.5bn National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory in California is no nearer to igniting a sustainable nuclear fusion burn - four years after its initial target date - according to a report by the US National Nuclear Security Administration (NNSA).

Location, timing and extent of wildfire vary by cause of ignition

USGS Publications Warehouse

Syphard, Alexandra D.; Keeley, Jon E.

2015-01-01

The increasing extent of wildfires has prompted investigation into alternative fire management approaches to complement the traditional strategies of fire suppression and fuels manipulation. Wildfire prevention through ignition reduction is an approach with potential for success, but ignitions result from a variety of causes. If some ignition sources result in higher levels of area burned, then ignition prevention programmes could be optimised to target these distributions in space and time. We investigated the most common ignition causes in two southern California sub-regions, where humans are responsible for more than 95% of all fires, and asked whether these causes exhibited distinct spatial or intra-annual temporal patterns, or resulted in different extents of fire in 10-29-year periods, depending on sub-region. Different ignition causes had distinct spatial patterns and those that burned the most area tended to occur in autumn months. Both the number of fires and area burned varied according to cause of ignition, but the cause of the most numerous fires was not always the cause of the greatest area burned. In both sub-regions, power line ignitions were one of the top two causes of area burned: the other major causes were arson in one sub-region and power equipment in the other. Equipment use also caused the largest number of fires in both sub-regions. These results have important implications for understanding why, where and how ignitions are caused, and in turn, how to develop strategies to prioritise and focus fire prevention efforts. Fire extent has increased tremendously in southern California, and because most fires are caused by humans, ignition reduction offers a potentially powerful management strategy, especially if optimised to reflect the distinct spatial and temporal distributions in different ignition causes.

Analysis of the laser ignition of methane/oxygen mixtures in a sub-scale rocket combustion chamber

NASA Astrophysics Data System (ADS)

Wohlhüter, Michael; Zhukov, Victor P.; Sender, Joachim; Schlechtriem, Stefan

2017-06-01

The laser ignition of methane/oxygen mixtures in a sub-scale rocket combustion chamber has been investigated numerically and experimentally. The ignition test case used in the present paper was generated during the In-Space Propulsion project (ISP-1), a project focused on the operation of propulsion systems in space, the handling of long idle periods between operations, and multiple reignitions under space conditions. Regarding the definition of the numerical simulation and the suitable domain for the current model, 2D and 3D simulations have been performed. Analysis shows that the usage of a 2D geometry is not suitable for this type of simulation, as the reduction of the geometry to a 2D domain significantly changes the conditions at the time of ignition and subsequently the flame development. The comparison of the numerical and experimental results shows a strong discrepancy in the pressure evolution and the combustion chamber pressure peak following the laser spark. The detailed analysis of the optical Schlieren and OH data leads to the conclusion that the pressure measurement system was not able to capture the strong pressure increase and the peak value in the combustion chamber during ignition. Although the timing in flame development following the laser spark is not captured appropriately, the 3D simulations reproduce the general ignition phenomena observed in the optical measurement systems, such as pressure evolution and injector flow characteristics.

Physics evaluation of compact tokamak ignition experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uckan, N.A.; Houlberg, W.A.; Sheffield, J.

1985-01-01

At present, several approaches for compact, high-field tokamak ignition experiments are being considered. A comprehensive method for analyzing the potential physics operating regimes and plasma performance characteristics of such ignition experiments with O-D (analytic) and 1-1/2-D (WHIST) transport models is presented. The results from both calculations are in agreement and show that there are regimes in parameter space in which a class of small (R/sub o/ approx. 1-2 m), high-field (B/sub o/ approx. 8-13 T) tokamaks with aB/sub o/S/q/sub */ approx. 25 +- 5 and kappa = b/a approx. 1.6-2.0 appears ignitable for a reasonable range of transport assumptions. Consideringmore » both the density and beta limits, an evaluation of the performance is presented for various forms of chi/sub e/ and chi/sub i/, including degradation at high power and sawtooth activity. The prospects of ohmic ignition are also examined. 16 refs., 13 figs.« less

Enhancing Ignition Probability and Fusion Yield in NIF Indirect Drive Targets with Applied Magnetic Fields

NASA Astrophysics Data System (ADS)

Perkins, L. John; Logan, B. Grant; Ho, Darwin; Zimmerman, George; Rhodes, Mark; Blackfield, Donald; Hawkins, Steven

2017-10-01

Imposed magnetic fields of tens of Tesla that increase to greater than 10 kT (100 MGauss) under capsule compression may relax conditions for ignition and propagating burn in indirect-drive ICF targets. This may allow attainment of ignition, or at least significant fusion energy yields, in presently-performing ICF targets on the National Ignition Facility that today are sub-marginal for thermonuclear burn through adverse hydrodynamic conditions at stagnation. Results of detailed 2D radiation-hydrodynamic-burn simulations applied to NIF capsule implosions with low-mode shape perturbations and residual kinetic energy loss indicate that such compressed fields may increase the probability for ignition through range reduction of fusion alpha particles, suppression of electron heat conduction and stabilization of higher-mode RT instabilities. Optimum initial applied fields are around 50 T. Off-line testing has been performed of a hohlraum coil and pulsed power supply that could be integrated on NIF; axial fields of 58T were obtained. Given the full plasma structure at capsule stagnation may be governed by 3-D resistive MHD, the formation of closed magnetic field lines might further augment ignition prospects. Experiments are now required to assess the potential of applied magnetic fields to NIF ICF ignition and burn. Work performed under auspices of U.S. DOE by LLNL under Contract DE-AC52-07NA27344.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haynam, C A; Sacks, R A; Moses, E I

We appreciate Stephen Bodner's continuing interest in the performance of the NIF laser system. However, we find it necessary to disagree with the conclusions he reached in his comments [Appl. Opt. 47, XXX (2008)] on 'National Ignition Facility Laser Performance Status' [Appl. Opt. 46, 3276 (2007)]. In fact, repeated and ongoing tests of the NIF beamlines have demonstrated that NIF can be expected not only to meet or exceed its requirements as established in the mid-1990s in the document National Ignition Facility Functional Requirements and Primary Criteria [Revision 1.3, Report NIF-LLNL-93-058 (1994)], but also to have the flexibility that providesmore » for successfully meeting an ever expanding range of mission goals, including those of ignition.« less

Software solutions manage the definition, operation, maintenance and configuration control of the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dobson, D; Churby, A; Krieger, E

2011-07-25

The National Ignition Facility (NIF) is the world's largest laser composed of millions of individual parts brought together to form one massive assembly. Maintaining control of the physical definition, status and configuration of this structure is a monumental undertaking yet critical to the validity of the shot experiment data and the safe operation of the facility. The NIF business application suite of software provides the means to effectively manage the definition, build, operation, maintenance and configuration control of all components of the National Ignition Facility. State of the art Computer Aided Design software applications are used to generate a virtualmore » model and assemblies. Engineering bills of material are controlled through the Enterprise Configuration Management System. This data structure is passed to the Enterprise Resource Planning system to create a manufacturing bill of material. Specific parts are serialized then tracked along their entire lifecycle providing visibility to the location and status of optical, target and diagnostic components that are key to assessing pre-shot machine readiness. Nearly forty thousand items requiring preventive, reactive and calibration maintenance are tracked through the System Maintenance & Reliability Tracking application to ensure proper operation. Radiological tracking applications ensure proper stewardship of radiological and hazardous materials and help provide a safe working environment for NIF personnel.« less

Liquid Oxygen Rotating Friction Ignition Testing of Aluminum and Titanium with Monel and Inconel for Rocket Engine Propulsion System Contamination Investigation

NASA Technical Reports Server (NTRS)

Peralta, S.; Rosales, Keisa R.; Stoltzfus, Joel M.

2009-01-01

Metallic contaminant was found in the liquid oxygen (LOX) pre-valve screen of the shuttle main engine propulsion system on two orbiter vehicles. To investigate the potential for an ignition, NASA Johnson Space Center White Sands Test Facility performed (modified) rotating friction ignition testing in LOX. This testing simulated a contaminant particle in the low-pressure oxygen turbo pump (LPOTP) and the high-pressure oxygen turbo pump (HPOTP) of the shuttle main propulsion system. Monel(R) K-500 and Inconel(R) 718 samples represented the LPOTP and HPOTP materials. Aluminum foil tape and titanium foil represented the contaminant particles. In both the Monel(R) and Inconel(R) material configurations, the aluminum foil tape samples did not ignite after 30 s of rubbing. In contrast, all of the titanium foil samples ignited regardless of the rubbing duration or material configuration. However, the titanium foil ignitions did not propagate to the Monel and Inconel materials.

Ignition of contaminants by impact of high-pressure oxygen

NASA Technical Reports Server (NTRS)

Pedley, Michael D.; Pao, Jenn-Hai; Bamford, Larry; Williams, Ralph E.; Plante, Barry

1988-01-01

The ignition of oil-film contaminants in high-pressure gaseous oxygen systems, caused by rapid pressurization, was investigated using the NASA/White Sands Test Facility's large-volume pneumatic impact test system. The test section consisted of stainless steel lines, contaminated on the inside surface with known amounts of Mobil DTE 24 oil and closed at one end, which was attached to a high-pressure oxygen system; the test section was pressurized to 48 MPa by opening a high-speed valve. Ignition of the oil was detected by a photocell attached to the closed end of the line. It was found that the frequency of ignition increased as a function of both the concentration of oil and of the pressure of the impacting oxygen. The threshold of ignition was between 25 and 65 mg/sq m. The results were correlated with the present NASA and Compressed Gas Association requirements for maximum levels of organic contaminants.

Catalytic ignition of hydrogen/oxygen

NASA Technical Reports Server (NTRS)

Green, James M.; Zurawski, Robert L.

1988-01-01

An experimental program was conducted to evaluate the catalytic ignition of gaseous hydrogen and oxygen. Shell 405 granular catalyst and a unique monolithic sponge catalyst were tested. Mixture ratio, mass flow rate, propellant inlet temperature, and back pressure were varied parametrically in testing to determine the operational limits of a catalytic igniter. The test results showed that the gaseous hydrogen/oxygen propellant combination can be ignited catalytically using Shell 405 catalyst over a wide range of mixture ratios, mass flow rates, and propellant injection temperatures. These operating conditions must be optimized to ensure reliable ignition for an extended period of time. The results of the experimental program and the established operational limits for a catalytic igniter using both the granular and monolithic catalysts are presented. The capabilities of a facility constructed to conduct the igniter testing and the advantages of a catalytic igniter over other ignition systems for gaseous hydrogen and oxygen are also discussed.

Science& Technology Review September 2003

DOE Office of Scientific and Technical Information (OSTI.GOV)

McMahon, D

2003-09-01

This September 2003 issue of ''Science and Technology Review'' covers the following articles: (1) ''The National Ignition Facility Is Born''; (2) ''The National Ignition Facility Comes to Life'' Over the last 15 years, thousands of Livermore engineers, scientists, and technicians as well as hundreds of industrial partners have worked to bring the National Ignition Facility into being. (3) ''Tracking the Activity of Bacteria Underground'' Using real-time polymerase chain reaction and liquid chromatography/tandem mass spectrometry, researchers at Livermore are gaining knowledge on how bacteria work underground to break down compounds of environmental concern. (4) ''When Every Second Counts--Pathogen Identification in Lessmore » Than a Minute'' Livermore has developed a system that can quickly identify airborne pathogens such as anthrax. (5) ''Portable Radiation Detector Provides Laboratory-Scale Precision in the Field'' A team of Livermore physicists and engineers has developed a handheld, mechanically cooled germanium detector designed to identify radioisotopes.« less

National Ignition Facility Control and Information System Operational Tools

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marshall, C D; Beeler, R G; Bowers, G A

The National Ignition Facility (NIF) in Livermore, California, is the world's highest-energy laser fusion system and one of the premier large scale scientific projects in the United States. The system is designed to setup and fire a laser shot to a fusion ignition or high energy density target at rates up to a shot every 4 hours. NIF has 192 laser beams delivering up to 1.8 MJ of energy to a {approx}2 mm target that is planned to produce >100 billion atm of pressure and temperatures of >100 million degrees centigrade. NIF is housed in a ten-story building footprint themore » size of three football fields as shown in Fig. 1. Commissioning was recently completed and NIF will be formally dedicated at Lawrence Livermore National Laboratory on May 29, 2009. The control system has 60,000 hardware controls points and employs 2 million lines of control system code. The control room has highly automated equipment setup prior to firing laser system shots. This automation has a data driven implementation that is conducive to dynamic modification and optimization depending on the shot goals defined by the end user experimenters. NIF has extensive facility machine history and infrastructure maintenance workflow tools both under development and deployed. An extensive operational tools suite has been developed to support facility operations including experimental shot setup, machine readiness, machine health and safety, and machine history. The following paragraphs discuss the current state and future upgrades to these four categories of operational tools.« less

X-ray penumbral imaging diagnostic developments at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Bachmann, B.; Abu-Shawareb, H.; Alexander, N.; Ayers, J.; Bailey, C. G.; Bell, P.; Benedetti, L. R.; Bradley, D.; Collins, G.; Divol, L.; Döppner, T.; Felker, S.; Field, J.; Forsman, A.; Galbraith, J. D.; Hardy, C. M.; Hilsabeck, T.; Izumi, N.; Jarrot, C.; Kilkenny, J.; Kramer, S.; Landen, O. L.; Ma, T.; MacPhee, A.; Masters, N.; Nagel, S. R.; Pak, A.; Patel, P.; Pickworth, L. A.; Ralph, J. E.; Reed, C.; Rygg, J. R.; Thorn, D. B.

2017-08-01

X-ray penumbral imaging has been successfully fielded on a variety of inertial confinement fusion (ICF) capsule implosion experiments on the National Ignition Facility (NIF). We have demonstrated sub-5 μm resolution imaging of stagnated plasma cores (hot spots) at x-ray energies from 6 to 30 keV. These measurements are crucial for improving our understanding of the hot deuterium-tritium fuel assembly, which can be affected by various mechanisms, including complex 3-D perturbations caused by the support tent, fill tube or capsule surface roughness. Here we present the progress on several approaches to improve x-ray penumbral imaging experiments on the NIF. We will discuss experimental setups that include penumbral imaging from multiple lines-of-sight, target mounted penumbral apertures and variably filtered penumbral images. Such setups will improve the signal-to-noise ratio and the spatial imaging resolution, with the goal of enabling spatially resolved measurements of the hot spot electron temperature and material mix in ICF implosions.

Fluence-compensated down-scattered neutron imaging using the neutron imaging system at the National Ignition Facility.

PubMed

Casey, D T; Volegov, P L; Merrill, F E; Munro, D H; Grim, G P; Landen, O L; Spears, B K; Fittinghoff, D N; Field, J E; Smalyuk, V A

2016-11-01

The Neutron Imaging System at the National Ignition Facility is used to observe the primary ∼14 MeV neutrons from the hotspot and down-scattered neutrons (6-12 MeV) from the assembled shell. Due to the strong spatial dependence of the primary neutron fluence through the dense shell, the down-scattered image is convolved with the primary-neutron fluence much like a backlighter profile. Using a characteristic scattering angle assumption, we estimate the primary neutron fluence and compensate the down-scattered image, which reveals information about asymmetry that is otherwise difficult to extract without invoking complicated models.

X-ray transport and radiation response assessment (XTRRA) experiments at the National Ignition Facility.

PubMed

Fournier, K B; Brown, C G; Yeoman, M F; Fisher, J H; Seiler, S W; Hinshelwood, D; Compton, S; Holdener, F R; Kemp, G E; Newlander, C D; Gilliam, R P; Froula, N; Lilly, M; Davis, J F; Lerch, Maj A; Blue, B E

2016-11-01

Our team has developed an experimental platform to evaluate the x-ray-generated stress and impulse in materials. Experimental activities include x-ray source development, design of the sample mounting hardware and sensors interfaced to the National Ignition Facility's diagnostics insertion system, and system integration into the facility. This paper focuses on the X-ray Transport and Radiation Response Assessment (XTRRA) test cassettes built for these experiments. The test cassette is designed to position six samples at three predetermined distances from the source, each known to within ±1% accuracy. Built-in calorimeters give in situ measurements of the x-ray environment along the sample lines of sight. The measured accuracy of sample responses as well as planned modifications to the XTRRA cassette is discussed.

Robust, Reliable Low Emission Gas Turbine Combustion of High Hydrogen Content Fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wooldridge, Margaret Stacy; Im, Hong Geum

2016-12-16

The effects of high hydrogen content fuels were studied using experimental, computational and theoretical approaches to understand the effects of mixture and state conditions on the ignition behavior of the fuels. A rapid compression facility (RCF) was used to measure the ignition delay time of hydrogen and carbon monoxide mixtures. The data were combined with results of previous studies to develop ignition regime criteria. Analytical theory and direct numerical simulation were used to validate and interpret the RCF ignition data. Based on the integrated information the ignition regime criteria were extended to non-dimensional metrics which enable application of the resultsmore » to practical gas turbine combustion systems.« less

Analysis of the NASA White Sands Test Facility (WSTF) Test System for Friction-Ignition of Metallic Materials

NASA Technical Reports Server (NTRS)

Shoffstall, Michael S.; Wilson, D. Bruce; Stoltzfus, Joel M.

2000-01-01

Friction is a known ignition source for metals in oxygen-enriched atmospheres. The test system developed by the NASA White Sands Test Facility in response to ASTM G-94 has been used successfully to determine the relative ignition from friction of numerous metallic materials and metallic materials pairs. These results have been ranked in terms of a pressure-velocity product (PV) as measured under the prescribed test conditions. A high value of 4.1(exp 8) watts per square meter for Inconel MA 754 is used to imply resistance to friction ignition, whereas a low value of 1.04(exp 8) watts per square meter for stainless steel 304 is taken as indicating material susceptible to friction ignition. No attempt has been made to relate PV values to other material properties. This work reports the analysis of the WSTF friction-ignition test system for producing fundamental properties of metallic materials relating to ignition through friction. Three materials, aluminum, titanium, and nickel were tested in the WSTF frictional ignition instrument system under atmospheres of oxygen or nitrogen. Test conditions were modified to reach a steady state of operation, that is applied, the force was reduced and the rotational speed was reduced. Additional temperature measurements were made on the stator sample. The aluminum immediately galled on contact (reproducible) and the test was stopped. Titanium immediately ignited as a result of non-uniform contact of the stator and rotor. This was reproducible. A portion of the stator sampled burned, but the test continued. Temperature measurements on the stator were used to validate the mathematical model used for estimating the interface (stator/rotor) temperature. These interface temperature measurements and the associate thermal flux into the stator were used to distinguish material-phase transitions, chemical reaction, and mechanical work. The mechanical work was used to analyze surface asperities in the materials and to estimate a coefficient of fiction. The coefficient of fiction was analyzed in terms of material properties that is, hardness, Young's modulus and elasticity/plasticity of the material.

Frictional Ignition Testing of Composite Materials

NASA Technical Reports Server (NTRS)

Peralta, Steve; Rosales, Keisa; Robinson, Michael J.; Stoltzfus, Joel

2006-01-01

The space flight community has been investigating lightweight composite materials for use in propellant tanks for both liquid and gaseous oxygen for space flight vehicles. The use of these materials presents some risks pertaining to ignition and burning hazards in the presence of oxygen. Through hazard analysis process, some ignition mechanisms have been identified as being potentially credible. One of the ignition mechanisms was reciprocal friction; however, test data do not exist that could be used to clear or fail these types of materials as "oxygen compatible" for the reciprocal friction ignition mechanism. Therefore, testing was performed at White Sands Test Facility (WSTF) to provide data to evaluate this ignition mechanism. This paper presents the test system, approach, data results, and findings of the reciprocal friction testing performed on composite sample materials being considered for propellant tanks.

Photon Doppler Velocimeter to Measure Entrained Additive Manufactured Bulk Metal Powders in Hot Subsonic and Supersonic Oxygen Gas

NASA Technical Reports Server (NTRS)

Tylka, Jonathan

2016-01-01

Parts produced by additive manufacturing, particularly selective laser melting (SLM), have been shown to silt metal particulate even after undergoing stringent precision aerospace cleaning processes (Lowrey 2016). As printed parts are used in oxygen systems with increased pressures, temperatures, and gas velocity, the risk of ignition by particle impact, the most common direct ignition source of metals in oxygen, substantially increases. The White Sands Test Facility (WSTF), in collaboration with Marshall Space Flight Center (MSFC), desires to test the ignitability of SLM metals by particle impact in heated oxygen. The existing test systems rely on gas velocity calculations to infer particle velocity in both subsonic and supersonic particle impact systems. Until now, it was not possible to directly measure particle velocity. To increase the fidelity of planned SLM ignition studies, it is necessary to validate that the Photon Doppler Velocimetry(PDV) test system can accurately measure particle velocity.

The National Ignition Facility: Transition to a User Facility

NASA Astrophysics Data System (ADS)

Moses, E. I.; Atherton, J.; Lagin, L.; Larson, D.; Keane, C.; MacGowan, B.; Patterson, R.; Spaeth, M.; Van Wonterghem, B.; Wegner, P.; Kauffman, R.

2016-03-01

The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) has been operational since March 2009 and has been transitioning to a user facility supporting ignition science, high energy density science (HEDS), national security applications, and fundamental science. The facility has achieved its design goal of 1.8 MJ and 500 TW of 3ω light on target, and has performed target experiments with 1.9 MJ at peak powers of 410 TW. The facility is on track to perform over 200 target shots this year in support of all of its user communities. The facility has nearly 60 diagnostic systems operational and has shown flexibility in laser pulse shape and performance to meet the requirements of its multiple users. Progress continues on its goal of demonstrating thermonuclear burn in the laboratory. It has performed over 40 indirect-drive experiments with cryogenic-layered capsules. New platforms are being developed for HEDS and fundamental science. Equation-of-state and material strength experiments have been done on a number of materials with pressures of over 50 MBars obtained in diamond, conditions never previously encountered in the laboratory and similar to those found in planetary interiors. Experiments are also in progress investigating radiation transport, hydrodynamic instabilities, and direct drive implosions. NIF continues to develop as an experimental facility. Advanced Radiographic Capability (ARC) is now being installed on NIF for producing high-energy radiographs of the imploded cores of ignition targets and for short pulse laser-plasma interaction experiments. One NIF beam is planned for conversion to two picosecond beams in 2014. Other new diagnostics such as x-ray Thomson scattering, low energy neutron spectrometer, and multi-layer reflecting x-ray optics are also planned. Incremental improvements in laser performance such as improved optics damage performance, beam balance, and back reflection control are being pursued.

The National Ignition Facility and Industry

NASA Astrophysics Data System (ADS)

Harri, J. G.; Paisner, J. A.; Lowdermilk, W. H.; Boyes, J. D.; Kumpan, S. A.; Sorem, M. S.

1994-09-01

The mission of the National Ignition Facility is to achieve ignition and gain in inertial confinement fusion targets in the laboratory. The facility will be used for defense applications such as weapons physics and weapons effects testing, and for civilian applications such as fusion energy development and fundamental studies of matter at high temperatures and densities. The National Ignition Facility construction project will require the best of our construction industries and its success will depend on the best products offered by hundreds of the nation's high technology companies. Three-fourths of the construction costs will be invested in industry. This article reviews the design, cost and schedule, and required industrial involvement associated with the construction project.

The 27.3 meter neutron time-of-flight system for the National Ignition Facility

NASA Astrophysics Data System (ADS)

Grim, G. P.; Morgan, G. L.; Aragonez, R.; Archuleta, T. N.; Bower, D. E.; Danly, C. R.; Drury, O. B.; Dzenitis, J. M.; Fatherley, V. E.; Felker, B.; Fittinghoff, D. N.; Guler, N.; Merrill, F. E.; Oertel, J. A.; Wilde, C. H.; Wilke, M. D.

2013-09-01

One of the scientific goals of the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory, Livermore CA, is to obtain thermonuclear ignition by compressing 2.2 mm diameter capsules filed with deuterium and tritium to densities approaching 1000 g/cm3 and temperatures in excess of 4 keV. Thefusion reaction d + t --> n + a results in a 14.03 MeV neutron providing a source of diagnostic particles to characterize the implosion. The spectrum of neutrons emanating from the assembly may be used to infer the fusion yield, plasma ion temperature, and fuel areal density, all key diagnostic quantities of implosion quality. The neutron time-of-flight (nToF) system co-located along the Neutron Imaging System line-of-site, (NIToF), is a set of 4 scintillation detectors located approximately 27.3 m from the implosion source. Neutron spectral information is inferred using arrival time at the detector. The NIToF system is described below, including the hardware elements, calibration data, analysis methods, and an example of its basic performance characteristics.

Self-ignition of S.I. engine model fuels: A shock tube investigation at high pressure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fieweger, K.; Blumenthal, R.; Adomeit, G.

1997-06-01

The self-ignition of several spark-ignition (SI) engine fuels (iso-octane, methanol, methyl tert-butyl ether and three different mixtures of iso-octane and n-heptane), mixed with air, was investigated experimentally under relevant engine conditions by the shock tube technique. Typical modes of the self-ignition process were registered cinematographically. For temperatures relevant to piston engine combustion, the self-ignition process always starts as an inhomogeneous, deflagrative mild ignition. This instant is defined by the ignition delay time, {tau}{sub defl}. The deflagration process in most cases is followed by a secondary explosion (DDT). This transition defines a second ignition delay time, {tau}{sub DDT}, which is amore » suitable approximation for the chemical ignition delay time, if the change of the thermodynamic conditions of the unburned test gas due to deflagration is taken into account. For iso-octane at p = 40 bar, a NTC (negative temperature coefficient), behavior connected with a two step (cool flame) self-ignition at low temperatures was observed. This process was very pronounced for rich and less pronounced for stoichiometric mixtures. The results of the {tau}{sub DDT} delays of the stoichiometric mixtures were shortened by the primary deflagration process in the temperature range between 800 and 1,000 K. Various mixtures of iso-octane and n-heptane were investigated. The results show a strong influence of the n-heptane fraction in the mixture, both on the ignition delay time and on the mode of self-ignition. The self-ignition of methanol and MTBE (methyl tert-butyl ether) is characterized by a very pronounced initial deflagration. For temperatures below 900 K (methanol: 800 K), no secondary explosion occurs. Taking into account the pressure increase due to deflagration, the measured delays {tau}{sub DDT} of the secondary explosion are shortened by up to one order of magnitude.« less

The Physics of Advanced High-Gain Targets for Inertial Fusion Energy

NASA Astrophysics Data System (ADS)

Perkins, L. John

2010-11-01

In ca. 2011-2012, the National Ignition Facility is poised to demonstrate fusion ignition and gain in the laboratory for the first time. This key milestone in the development of inertial confinement fusion (ICF) can be expected to engender interest in the development of inertial fusion energy (IFE) and expanded efforts on a number of advanced targets that may achieve high fusion energy gain at lower driver energies. In this tutorial talk, we will discuss the physics underlying ICF ignition and thermonuclear burn, examine the requirements for high gain, and outline candidate R&D programs that will be required to assess the performance of these target concepts under various driver systems including lasers, heavy-ions and pulsed power. Such target concepts include those operating by fast ignition, shock ignition, impact ignition, dual-density, magnetically-insulated, one- and two-sided drive, etc., some of which may have potential to burn advanced, non-DT fusion fuels. We will then delineate the role of such targets in their application to the production of high average fusion power. Here, systems studies of IFE economics suggest that we should strive for target fusion gains of around 100 at drive energies of 1MJ, together with corresponding rep-rates of up to 10Hz and driver electrical efficiencies around 15%. In future years, there may be exciting opportunities to study such ``innovative confinement concepts'' with prospects of fielding them on facilities such as NIF to obtain high fusion energy gains on a single shot basis.

Coil-On-Plug Ignition for Oxygen/Methane Liquid Rocket Engines in Thermal-Vacuum Environments

NASA Technical Reports Server (NTRS)

Melcher, John C.; Atwell, Matthew J.; Morehead, Robert L.; Hurlbert, Eric A.; Bugarin, Luz; Chaidez, Mariana

2017-01-01

A coil-on-plug ignition system has been developed and tested for Liquid Oxygen (LOX)/liquid methane (LCH4) rocket engines operating in thermal vacuum conditions. The igniters were developed and tested as part of the Integrated Cryogenic Propulsion Test Article (ICPTA), previously tested as part of the Project Morpheus test vehicle. The ICPTA uses an integrated, pressure-fed, cryogenic LOX/LCH4 propulsion system including a reaction control system (RCS) and a main engine. The ICPTA was tested at NASA Glenn Research Center's Plum Brook Station in the Spacecraft Propulsion Research Facility (B-2) under vacuum and thermal vacuum conditions. A coil-on-plug ignition system has been developed to successfully demonstrate ignition reliability at these conditions while preventing corona discharge issues. The ICPTA uses spark plug ignition for both the main engine igniter and the RCS. The coil-on-plug configuration eliminates the conventional high-voltage spark plug cable by combining the coil and the spark plug into a single component. Prior to ICPTA testing at Plum Brook, component-level reaction control engine (RCE) and main engine igniter testing was conducted at NASA Johnson Space Center (JSC), which demonstrated successful hot-fire ignition using the coil-on-plug from sea-level ambient conditions down to 10(exp -2) torr. Integrated vehicle hot-fire testing at JSC demonstrated electrical and command/data system performance. Lastly, hot-fire testing at Plum Brook demonstrated successful ignitions at simulated altitude conditions at 30 torr and cold thermal-vacuum conditions at 6 torr. The test campaign successfully proved that coil-on-plug technology will enable integrated LOX/LCH4 propulsion systems in future spacecraft.

Coil-On-Plug Ignition for LOX/Methane Liquid Rocket Engines in Thermal Vacuum Environments

NASA Technical Reports Server (NTRS)

Melcher, John C.; Atwell, Matthew J.; Morehead, Robert L.; Hurlbert, Eric A.; Bugarin, Luz; Chaidez, Mariana

2017-01-01

A coil-on-plug ignition system has been developed and tested for Liquid Oxygen (LOX) / liquid methane rocket engines operating in thermal vacuum conditions. The igniters were developed and tested as part of the Integrated Cryogenic Propulsion Test Article (ICPTA), previously tested as part of the Project Morpheus test vehicle. The ICPTA uses an integrated, pressure-fed, cryogenic LOX/methane propulsion system including a reaction control system (RCS) and a main engine. The ICPTA was tested at NASA Glenn Research Center's Plum Brook Station in the Spacecraft Propulsion Research Facility (B-2) under vacuum and thermal vacuum conditions. In order to successfully demonstrate ignition reliability in the vacuum conditions and eliminate corona discharge issues, a coil-on-plug ignition system has been developed. The ICPTA uses spark-plug ignition for both the main engine igniter and the RCS. The coil-on-plug configuration eliminates the conventional high-voltage spark plug cable by combining the coil and the spark-plug into a single component. Prior to ICPTA testing at Plum Brook, component-level reaction control engine (RCE) and main engine igniter testing was conducted at NASA Johnson Space Center (JSC), which demonstrated successful hot-fire ignition using the coil-on-plug from sea-level ambient conditions down to 10(exp.-2) torr. Integrated vehicle hot-fire testing at JSC demonstrated electrical and command/data system performance. Lastly, Plum Brook testing demonstrated successful ignitions at simulated altitude conditions at 30 torr and cold thermal-vacuum conditions at 6 torr. The test campaign successfully proved that coil-on-plug technology will enable integrated LOX/methane propulsion systems in future spacecraft.

Flow Friction or Spontaneous Ignition?

NASA Technical Reports Server (NTRS)

Stoltzfus, Joel M.; Gallus, Timothy D.; Sparks, Kyle

2012-01-01

"Flow friction," a proposed ignition mechanism in oxygen systems, has proved elusive in attempts at experimental verification. In this paper, the literature regarding flow friction is reviewed and the experimental verification attempts are briefly discussed. Another ignition mechanism, a form of spontaneous combustion, is proposed as an explanation for at least some of the fire events that have been attributed to flow friction in the literature. In addition, the results of a failure analysis performed at NASA Johnson Space Center White Sands Test Facility are presented, and the observations indicate that spontaneous combustion was the most likely cause of the fire in this 2000 psig (14 MPa) oxygen-enriched system.

A robust in-situ warp-correction algorithm for VISAR streak camera data at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Labaria, George R.; Warrick, Abbie L.; Celliers, Peter M.; Kalantar, Daniel H.

2015-02-01

The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory is a 192-beam pulsed laser system for high energy density physics experiments. Sophisticated diagnostics have been designed around key performance metrics to achieve ignition. The Velocity Interferometer System for Any Reflector (VISAR) is the primary diagnostic for measuring the timing of shocks induced into an ignition capsule. The VISAR system utilizes three streak cameras; these streak cameras are inherently nonlinear and require warp corrections to remove these nonlinear effects. A detailed calibration procedure has been developed with National Security Technologies (NSTec) and applied to the camera correction analysis in production. However, the camera nonlinearities drift over time affecting the performance of this method. An in-situ fiber array is used to inject a comb of pulses to generate a calibration correction in order to meet the timing accuracy requirements of VISAR. We develop a robust algorithm for the analysis of the comb calibration images to generate the warp correction that is then applied to the data images. Our algorithm utilizes the method of thin-plate splines (TPS) to model the complex nonlinear distortions in the streak camera data. In this paper, we focus on the theory and implementation of the TPS warp-correction algorithm for the use in a production environment.

Electron Shock Ignition of Inertial Fusion Targets

DOE PAGES

Shang, W. L.; Betti, R.; Hu, S. X.; ...

2017-11-07

Here, it is shown that inertial fusion targets designed with low implosion velocities can be shock ignited using laser–plasma interaction generated hot electrons (hot-e) to obtain high-energy gains. These designs are robust to multimode asymmetries and are predicted to ignite even for significantly distorted implosions. Electron shock ignition requires tens of kilojoules of hot-e, which can only be produced on a large laser facility like the National Ignition Facility, with the laser to hot-e conversion efficiency greater than 10% at laser intensities ~10 16 W/cm 2.

Electron Shock Ignition of Inertial Fusion Targets

NASA Astrophysics Data System (ADS)

Shang, W. L.; Betti, R.; Hu, S. X.; Woo, K.; Hao, L.; Ren, C.; Christopherson, A. R.; Bose, A.; Theobald, W.

2017-11-01

It is shown that inertial confinement fusion targets designed with low implosion velocities can be shock-ignited using laser-plasma interaction generated hot electrons (hot-e 's) to obtain high energy gains. These designs are robust to multimode asymmetries and are predicted to ignite even for significantly distorted implosions. Electron shock ignition requires tens of kilojoules of hot-e 's which can be produced only at a large laser facility like the National Ignition Facility, with the laser-to-hot-e conversion efficiency greater than 10% at laser intensities ˜1016 W /cm2 .

Electron Shock Ignition of Inertial Fusion Targets.

PubMed

Shang, W L; Betti, R; Hu, S X; Woo, K; Hao, L; Ren, C; Christopherson, A R; Bose, A; Theobald, W

2017-11-10

It is shown that inertial confinement fusion targets designed with low implosion velocities can be shock-ignited using laser-plasma interaction generated hot electrons (hot-e's) to obtain high energy gains. These designs are robust to multimode asymmetries and are predicted to ignite even for significantly distorted implosions. Electron shock ignition requires tens of kilojoules of hot-e's which can be produced only at a large laser facility like the National Ignition Facility, with the laser-to-hot-e conversion efficiency greater than 10% at laser intensities ∼10^{16}  W/cm^{2}.

LLE 2008 annual report, October 2007 - September 2008

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2009-01-31

The research program at the University of Rochester’s Laboratory for Laser Energetics (LLE) focuses on inertial confinement fusion (ICF) research supporting the goal of achieving ignition on the National Ignition Facility (NIF). This program includes the full use of the OMEGA EP Laser System. Within the National Ignition Campaign (NIC), LLE is the lead laboratory for the validation of the performance of cryogenic target implosions, essential to all forms of ICF ignition. LLE has taken responsibility for a number of critical elements within the Integrated Experimental Teams (IET’s) supporting the demonstration of indirect-drive ignition on the NIF and is themore » lead laboratory for the validation of the polardrive approach to ignition on the NIF. LLE is also developing, testing, and building a number of diagnostics to be deployed on the NIF for the NIC.« less

Development of Augmented Spark Impinging Igniter System for Methane Engines

NASA Technical Reports Server (NTRS)

Marshall, William M.; Osborne, Robin J.; Greene, Sandra E.

2017-01-01

The Lunar Cargo Transportation and Landing by Soft Touchdown (Lunar CATALYST) program is establishing multiple no-funds-exchanged Space Act Agreement (SAA) partnerships with U.S. private sector entities. The purpose of this program is to encourage the development of robotic lunar landers that can be integrated with U.S. commercial launch capabilities to deliver payloads to the lunar surface. NASA can share technology and expertise under the SAA for the benefit of the CATALYST partners. MSFC seeking to vacuum test Augmented Spark Impinging (ASI) igniter with methane and new exciter units to support CATALYST partners and NASA programs. ASI has previously been used/tested successfully at sea-level, with both O2/CH4 and O2/H2 propellants. Conventional ignition exciter systems historically experienced corona discharge issues in vacuum. Often utilized purging or atmospheric sealing on high voltage lead to remedy. Compact systems developed since PCAD could eliminate the high-voltage lead and directly couple the exciter to the spark igniter. MSFC developed Augmented Spark Impinging (ASI) igniter. Successfully used in several sea-level test programs. Plasma-assisted design. Portion of ox flow is used to generate hot plasma. Impinging flows downstream of plasma. Additional fuel flow down torch tube sleeve for cooling near stoichiometric torch flame. Testing done at NASA GRC Altitude Combustion Stand (ACS) facility 2000-lbf class facility with altitude simulation up to around 100,000 ft. (0.2 psia [10 Torr]) via nitrogen driven ejectors. Propellant conditioning systems can provide temperature control of LOX/CH4 up to test article.

Early-time radiation flux symmetry optimization and its effect on gas-filled hohlraum ignition targets on the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milovich, J. L., E-mail: milovich1@llnl.gov; Dewald, E. L.; Pak, A.

2016-03-15

Achieving ignition on the National Ignition Facility (NIF) is tied to our ability to control and minimize deviations from sphericity of the capsule implosion. Low-mode asymmetries of the hot spot result from the combined effect of radiation drive asymmetries throughout the laser pulse and initial roughness on the capsule surface. In this paper, we report on simulations and experiments designed to assess, measure, and correct the drive asymmetries produced by the early-time (≈first 2 ns or “picket”) period of the laser pulse. The drive asymmetry during the picket is commonly thought to introduce distortions in the hot-spot shape at ignition time.more » However, a more subtle effect not previously considered is that it also leads to an asymmetry in shock velocity and timing, thereby increasing the fuel adiabat and reducing the margin for ignition. It is shown via hydrodynamic simulations that minimizing this effect requires that the early-time asymmetry be kept below 7.5% in the second Legendre mode (P{sub 2}), thus keeping the loss of performance margin below ≈10% for a layered implosion. Asymmetries during the picket of the laser pulse are measured using the instantaneous self-emission of a high-Z re-emission sphere in place of an ignition capsule in a hohlraum with large azimuthal diagnostic windows. Three dimensional simulations using the code HYDRA (to capture the effect of non-azimuthal hohlraum features) coupled to a cross-beam energy transfer model [Michel et al., Phys. Plasmas 17, 056305 (2010)] are used to establish the surrogacy of the re-emit target and to assess the early-time drive symmetry. Calculations using this model exhibit the same sensitivity to variations in the relative input powers between the different cones of NIF beams as measured for the “Rev5” CH target [Haan et al., Phys Plasmas 18, 051001 (2011)] and reported by Dewald et al. [Phys. Rev. Lett. 111, 235001 (2013)]. The same methodology applied to recently improved implosions using different hohlraum geometries and picket powers show good agreement with experimental data.« less

Control and Information Systems for the National Ignition Facility

DOE PAGES

Brunton, Gordon; Casey, Allan; Christensen, Marvin; ...

2017-03-23

Orchestration of every National Ignition Facility (NIF) shot cycle is managed by the Integrated Computer Control System (ICCS), which uses a scalable software architecture running code on more than 1950 front-end processors, embedded controllers, and supervisory servers. The ICCS operates laser and industrial control hardware containing 66 000 control and monitor points to ensure that all of NIF’s laser beams arrive at the target within 30 ps of each other and are aligned to a pointing accuracy of less than 50 μm root-mean-square, while ensuring that a host of diagnostic instruments record data in a few billionths of a second.more » NIF’s automated control subsystems are built from a common object-oriented software framework that distributes the software across the computer network and achieves interoperation between different software languages and target architectures. A large suite of business and scientific software tools supports experimental planning, experimental setup, facility configuration, and post-shot analysis. Standard business services using open-source software, commercial workflow tools, and database and messaging technologies have been developed. An information technology infrastructure consisting of servers, network devices, and storage provides the foundation for these systems. Thus, this work is an overview of the control and information systems used to support a wide variety of experiments during the National Ignition Campaign.« less

Control and Information Systems for the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brunton, Gordon; Casey, Allan; Christensen, Marvin

Orchestration of every National Ignition Facility (NIF) shot cycle is managed by the Integrated Computer Control System (ICCS), which uses a scalable software architecture running code on more than 1950 front-end processors, embedded controllers, and supervisory servers. The ICCS operates laser and industrial control hardware containing 66 000 control and monitor points to ensure that all of NIF’s laser beams arrive at the target within 30 ps of each other and are aligned to a pointing accuracy of less than 50 μm root-mean-square, while ensuring that a host of diagnostic instruments record data in a few billionths of a second.more » NIF’s automated control subsystems are built from a common object-oriented software framework that distributes the software across the computer network and achieves interoperation between different software languages and target architectures. A large suite of business and scientific software tools supports experimental planning, experimental setup, facility configuration, and post-shot analysis. Standard business services using open-source software, commercial workflow tools, and database and messaging technologies have been developed. An information technology infrastructure consisting of servers, network devices, and storage provides the foundation for these systems. Thus, this work is an overview of the control and information systems used to support a wide variety of experiments during the National Ignition Campaign.« less

On thermonuclear ignition criterion at the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Baolian; Kwan, Thomas J. T.; Wang, Yi-Ming

2014-10-15

Sustained thermonuclear fusion at the National Ignition Facility remains elusive. Although recent experiments approached or exceeded the anticipated ignition thresholds, the nuclear performance of the laser-driven capsules was well below predictions in terms of energy and neutron production. Such discrepancies between expectations and reality motivate a reassessment of the physics of ignition. We have developed a predictive analytical model from fundamental physics principles. Based on the model, we obtained a general thermonuclear ignition criterion in terms of the areal density and temperature of the hot fuel. This newly derived ignition threshold and its alternative forms explicitly show the minimum requirementsmore » of the hot fuel pressure, mass, areal density, and burn fraction for achieving ignition. Comparison of our criterion with existing theories, simulations, and the experimental data shows that our ignition threshold is more stringent than those in the existing literature and that our results are consistent with the experiments.« less

A technique for extending by ∼10{sup 3} the dynamic range of compact proton spectrometers for diagnosing ICF implosions on the National Ignition Facility and OMEGA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sio, H., E-mail: hsio@mit.edu; Séguin, F. H.; Frenje, J. A.

Wedge Range Filter (WRF) proton spectrometers are routinely used on OMEGA and the NIF for diagnosing ρR and ρR asymmetries in direct- and indirect-drive implosions of D{sup 3}He-, D{sub 2}-, and DT-gas-filled capsules. By measuring the optical opacity distribution in CR-39 due to proton tracks in high-yield applications, as opposed to counting individual tracks, WRF dynamic range can be extended by 10{sup 2} for obtaining the spectral shape, and by 10{sup 3} for mean energy (ρR) measurement, corresponding to proton fluences of 10{sup 8} and 10{sup 9} cm{sup −2}, respectively. Using this new technique, ρR asymmetries can be measured duringmore » both shock and compression burn (proton yield ∼10{sup 8} and ∼10{sup 12}, respectively) in 2-shock National Ignition Facility implosions with the standard WRF accuracy of ±∼10 mg/cm{sup 2}.« less

Machining of Two-Dimensional Sinusoidal Defects on Ignition-Type Capsules to Study Hydrodynamic Instability at the National Ignition Facility

DOE PAGES

Giraldez, E. M.; Hoppe Jr., M. L.; Hoover, D. E.; ...

2016-07-07

Hydrodynamic instability growth and its effects on capsule implosion performance are being studied at the National Ignition Facility (NIF). Experimental results have shown that low-mode instabilities are the primary culprit for yield degradation. Ignition type capsules with machined 2D sinusoidal defects were used to measure low-mode hydrodynamic instability growth in the acceleration phase of the capsule implosion. The capsules were imploded using ignition-relevant laser pulses and the ablation-front modulation growth was measured using x-ray radiography. The experimentally measured growth was in good agreement with simulations.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edward Moses

The National Ignition Facility, the world's largest laser system, was dedicated at a ceremony on May 29, 2009 at Lawrence Livermore National Laboratory. These are the remarks by NIF Director Edward Moses.

Ignition Characterization Tests of the LOX/Ethanol Propellant Combination

NASA Technical Reports Server (NTRS)

Popp, Christopher G.; Robinson, Philip J.; Veith, Eric M.

2004-01-01

A series of contracts have been issued by the Marshall Space Flight Center (MSFC) of the National Aeronautics and Space Administration (NASA) to explore candidate technologies considered to be important for the Next Generation Launch Technology (NGLT) effort. One aspect of the NGLT effort is to explore the potential of incorporating non-toxic propellants for Reaction Control Subsystems (RCS). Contract NAS8-01109 has been issued to Aerojet to develop a dual thrust Reaction Control Engine (RCE) that utilizes liquid oxygen and ethanol as the propellants. The dual thrust RCE incorporates a primary thrust level of 870 lbf, and a vernier thrust level of 10 - 30 lbf. Aerojet has designed and tested a workhorse LOX igniter to determine LOX/Ethanol ignition characteristics as part of a risk mitigation effort for the dual thrust RCE design. The objective of the ignition testing was to demonstrate successfid ignition from GOX to LOX, encompassing potential two-phase flow conditions. The workhorse igniter was designed to accommodate the full LOX design flowrate, as well as a reduced GOX flowrate. It was reasoned that the initial LOX flow through the igniter would flash to GOX due to the inherent heat stored in the hardware, causing a reduced oxygen flowrate because of a choked, or sonic, flow condition through the injection elements. As LOX flow continued, the inherent heat of the test hardware would be removed and the hardware would chill-in, with the injected oxygen flow transitioning from cold GOX through two-phase flow to subcooled LOX. Pressure and temperature instrumentation permitted oxygen state points to be determined, and gas-side igniter chamber thermocouples provided chamber thermal profile characteristics. The cold flow chamber pressure (P(sub c)) for each test was determined and coupled with the igniter chamber diameter (D(sub c)) to calculate the characteristic quench parameter (P(sub c) x D(sub c)), which was plotted as a function of core mixture ratio, MR(sub c). Ignition limits were determined over a broad range of valve inlet conditions, and ignition was demonstrated with oxygen inlet conditions that ranged from subcooled 173 R LOX to 480 R GQX. Once ignited at cold GOX conditions, combustion was continuous as the hardware chilled in and the core mixture ratio transitioned from values near 1.0 to over 12.5.

Combustion characteristics of fine- and micro-pulverized coal in the mixture of O{sub 2}/CO{sub 2}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiangyong Huang; Xiumin Jiang; Xiangxin Han

The effects of oxygen concentration, particle size, and heating rate on the coal combustion characteristics under an O{sub 2}/CO{sub 2} atmosphere were investigated. The results indicated that the oxygen concentration played the most important role. As the oxygen concentration increases, the ignition and burnout temperatures decrease and the comprehensive combustion property index S increases. Moreover, the improvement of the oxygen concentration intensified the effects of the other factors. The ignition mechanism changes from hetero-homogeneous type to homogeneous type as the oxygen concentration increases. The ignition and burnout temperatures decrease slightly as the mean particle size decreases, and the index Smore » increases measurably as the mean particle size decreases. The heating rate has different effects on the ignition temperature, burnout temperature, and index S at different oxygen concentrations. 19 refs., 9 figs., 2 tabs.« less

Short Pulse Laser Applications Design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Town, R J; Clark, D S; Kemp, A J

We are applying our recently developed, LDRD-funded computational simulation tool to optimize and develop applications of Fast Ignition (FI) for stockpile stewardship. This report summarizes the work performed during a one-year exploratory research LDRD to develop FI point designs for the National Ignition Facility (NIF). These results were sufficiently encouraging to propose successfully a strategic initiative LDRD to design and perform the definitive FI experiment on the NIF. Ignition experiments on the National Ignition Facility (NIF) will begin in 2010 using the central hot spot (CHS) approach, which relies on the simultaneous compression and ignition of a spherical fuel capsule.more » Unlike this approach, the fast ignition (FI) method separates fuel compression from the ignition phase. In the compression phase, a laser such as NIF is used to implode a shell either directly, or by x rays generated from the hohlraum wall, to form a compact dense ({approx}300 g/cm{sup 3}) fuel mass with an areal density of {approx}3.0 g/cm{sup 2}. To ignite such a fuel assembly requires depositing {approx}20kJ into a {approx}35 {micro}m spot delivered in a short time compared to the fuel disassembly time ({approx}20ps). This energy is delivered during the ignition phase by relativistic electrons generated by the interaction of an ultra-short high-intensity laser. The main advantages of FI over the CHS approach are higher gain, a lower ignition threshold, and a relaxation of the stringent symmetry requirements required by the CHS approach. There is worldwide interest in FI and its associated science. Major experimental facilities are being constructed which will enable 'proof of principle' tests of FI in integrated subignition experiments, most notably the OMEGA-EP facility at the University of Rochester's Laboratory of Laser Energetics and the FIREX facility at Osaka University in Japan. Also, scientists in the European Union have recently proposed the construction of a new FI facility, called HiPER, designed to demonstrate FI. Our design work has focused on the NIF, which is the only facility capable of forming a full-scale hydro assembly, and could be adapted for full-scale FI by the conversion of additional beams to short-pulse operation.« less

Activation energy of tantalum-tungsten oxide thermite reactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cervantes, Octavio G.; Munir, Zuhair A.; Chemical Engineering and Materials Science, University of California, Davis, CA

2011-01-15

The activation energy of a sol-gel (SG) derived tantalum-tungsten oxide thermite composite was determined using the Kissinger isoconversion method. The SG derived powder was consolidated using the high-pressure spark plasma sintering (HPSPS) technique at 300 and 400 C. The ignition temperatures were investigated under high heating rates (500-2000 C min{sup -1}). Such heating rates were required in order to ignite the thermite composite. Samples consolidated at 300 C exhibit an abrupt change in temperature response prior to the main ignition temperature. This change in temperature response is attributed to the crystallization of the amorphous WO{sub 3} in the SG derivedmore » Ta-WO{sub 3} thermite composite and not to a pre-ignition reaction between the constituents. Ignition temperatures for the Ta-WO{sub 3} thermite ranged from approximately 465 to 670 C. The activation energies of the SG derived Ta-WO{sub 3} thermite composite consolidated at 300 and 400 C were determined to be 38{+-} 2 kJ mol{sup -1} and 57 {+-} 2 kJ mol{sup -1}, respectively. (author)« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shang, W. L.; Betti, R.; Hu, S. X.

Here, it is shown that inertial fusion targets designed with low implosion velocities can be shock ignited using laser–plasma interaction generated hot electrons (hot-e) to obtain high-energy gains. These designs are robust to multimode asymmetries and are predicted to ignite even for significantly distorted implosions. Electron shock ignition requires tens of kilojoules of hot-e, which can only be produced on a large laser facility like the National Ignition Facility, with the laser to hot-e conversion efficiency greater than 10% at laser intensities ~10 16 W/cm 2.

Capsule Performance Optimization in the National Ignition Campaign

DOE Office of Scientific and Technical Information (OSTI.GOV)

Landen, O L; MacGowan, B J; Haan, S W

2009-10-13

A capsule performance optimization campaign will be conducted at the National Ignition Facility to substantially increase the probability of ignition. The campaign will experimentally correct for residual uncertainties in the implosion and hohlraum physics used in our radiation-hydrodynamic computational models before proceeding to cryogenic-layered implosions and ignition attempts. The required tuning techniques using a variety of ignition capsule surrogates have been demonstrated at the Omega facility under scaled hohlraum and capsule conditions relevant to the ignition design and shown to meet the required sensitivity and accuracy. In addition, a roll-up of all expected random and systematic uncertainties in setting themore » key ignition laser and target parameters due to residual measurement, calibration, cross-coupling, surrogacy, and scale-up errors has been derived that meets the required budget.« less

Capsule performance optimization in the national ignition campaign

NASA Astrophysics Data System (ADS)

Landen, O. L.; MacGowan, B. J.; Haan, S. W.; Edwards, J.

2010-08-01

A capsule performance optimization campaign will be conducted at the National Ignition Facility [1] to substantially increase the probability of ignition. The campaign will experimentally correct for residual uncertainties in the implosion and hohlraum physics used in our radiation-hydrodynamic computational models before proceeding to cryogenic-layered implosions and ignition attempts. The required tuning techniques using a variety of ignition capsule surrogates have been demonstrated at the Omega facility under scaled hohlraum and capsule conditions relevant to the ignition design and shown to meet the required sensitivity and accuracy. In addition, a roll-up of all expected random and systematic uncertainties in setting the key ignition laser and target parameters due to residual measurement, calibration, cross-coupling, surrogacy, and scale-up errors has been derived that meets the required budget.

Mitigation of laser damage on National Ignition Facility optics in volume production

NASA Astrophysics Data System (ADS)

Folta, James; Nostrand, Mike; Honig, John; Wong, Nan; Ravizza, Frank; Geraghty, Paul; Taranowski, Mike; Johnson, Gary; Larkin, Glenn; Ravizza, Doug; Peterson, John; Welday, Brian; Wegner, Paul

2013-12-01

The National Ignition Facility has recently achieved the milestone of delivering over 1.8 MJ and 500 TW of 351 nm laser energy and power on target, which required average fluences up to 9 J/cm2 (3 ns equivalent) in the final optics system. Commercial fused silica laser-grade UV optics typically have a maximum operating threshold of 5 J/cm2. We have developed an optics recycling process which enables NIF to operate above the laser damage initiation and growth thresholds. We previously reported a method to mitigate laser damage with laser ablation of the damage site to leave benign cone shaped pits. We have since developed a production facility with four mitigation systems capable of performing the mitigation protocols on full-sized (430 mm) optics in volume production. We have successfully repaired over 700 NIF optics (unique serial numbers), some of which have been recycled as many as 11 times. We describe the mitigation systems, the optics recycle loop process, and optics recycle production data.

A Robust In-Situ Warp-Correction Algorithm For VISAR Streak Camera Data at the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Labaria, George R.; Warrick, Abbie L.; Celliers, Peter M.

2015-01-12

The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory is a 192-beam pulsed laser system for high-energy-density physics experiments. Sophisticated diagnostics have been designed around key performance metrics to achieve ignition. The Velocity Interferometer System for Any Reflector (VISAR) is the primary diagnostic for measuring the timing of shocks induced into an ignition capsule. The VISAR system utilizes three streak cameras; these streak cameras are inherently nonlinear and require warp corrections to remove these nonlinear effects. A detailed calibration procedure has been developed with National Security Technologies (NSTec) and applied to the camera correction analysis in production. However,more » the camera nonlinearities drift over time, affecting the performance of this method. An in-situ fiber array is used to inject a comb of pulses to generate a calibration correction in order to meet the timing accuracy requirements of VISAR. We develop a robust algorithm for the analysis of the comb calibration images to generate the warp correction that is then applied to the data images. Our algorithm utilizes the method of thin-plate splines (TPS) to model the complex nonlinear distortions in the streak camera data. In this paper, we focus on the theory and implementation of the TPS warp-correction algorithm for the use in a production environment.« less

Assessment of multiple DWI offender restrictions

DOT National Transportation Integrated Search

1989-12-01

This report discusses nine new approaches for reducing recidivism among multiple DWI offenders: dedicated detention facilities, diversion programs, electronic monitoring, ignition interlock systems, intensive probation supervision, publishing offende...

Aperture tolerances for neutron-imaging systems in inertial confinement fusion.

PubMed

Ghilea, M C; Sangster, T C; Meyerhofer, D D; Lerche, R A; Disdier, L

2008-02-01

Neutron-imaging systems are being considered as an ignition diagnostic for the National Ignition Facility (NIF) [Hogan et al., Nucl. Fusion 41, 567 (2001)]. Given the importance of these systems, a neutron-imaging design tool is being used to quantify the effects of aperture fabrication and alignment tolerances on reconstructed neutron images for inertial confinement fusion. The simulations indicate that alignment tolerances of more than 1 mrad would introduce measurable features in a reconstructed image for both pinholes and penumbral aperture systems. These simulations further show that penumbral apertures are several times less sensitive to fabrication errors than pinhole apertures.

Improved Performance of High Areal Density Indirect Drive Implosions at the National Ignition Facility using a Four-Shock Adiabat Shaped Drive

DOE PAGES

Casey, D. T.; Milovich, J. L.; Smalyuk, V. A.; ...

2015-09-01

Hydrodynamic instabilities can cause capsule defects and other perturbations to grow and degrade implosion performance in ignition experiments at the National Ignition Facility (NIF). Here, we show the first experimental demonstration that a strong unsupported first shock in indirect drive implosions at the NIF reduces ablation front instability growth leading to a 3 to 10 times higher yield with fuel ρR > 1 g=cm 2. This work shows the importance of ablation front instability growth during the National Ignition Campaign and may provide a path to improved performance at the high compression necessary for ignition.

Demonstration of high-energy 2 omega (526.5 nm) operation on the National Ignition Facility Laser System.

PubMed

Heestand, G M; Haynam, C A; Wegner, P J; Bowers, M W; Dixit, S N; Erbert, G V; Henesian, M A; Hermann, M R; Jancaitis, K S; Knittel, K; Kohut, T; Lindl, J D; Manes, K R; Marshall, C D; Mehta, N C; Menapace, J; Moses, E; Murray, J R; Nostrand, M C; Orth, C D; Patterson, R; Sacks, R A; Saunders, R; Shaw, M J; Spaeth, M; Sutton, S B; Williams, W H; Widmayer, C C; White, R K; Whitman, P K; Yang, S T; Van Wonterghem, B M

2008-07-01

A single beamline of the National Ignition Facility (NIF) has been operated at a wavelength of 526.5 nm (2 omega) by frequency converting the fundamental 1053 nm (1 omega) wavelength with an 18.2 mm thick type-I potassium dihydrogen phosphate (KDP) second-harmonic generator (SHG) crystal. Second-harmonic energies of up to 17.9 kJ were measured at the final optics focal plane with a conversion efficiency of 82%. For a similarly configured 192-beam NIF, this scales to a total 2 omega energy of 3.4 MJ full NIF equivalent (FNE).

Vehicle electrical system state controller

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bissontz, Jay E.

A motor vehicle electrical power distribution system includes a plurality of distribution sub-systems, an electrical power storage sub-system and a plurality of switching devices for selective connection of elements of and loads on the power distribution system to the electrical power storage sub-system. A state transition initiator provides inputs to control system operation of switching devices to change the states of the power distribution system. The state transition initiator has a plurality of positions selection of which can initiate a state transition. The state transition initiator can emulate a four position rotary ignition switch. Fail safe power cutoff switches providemore » high voltage switching device protection.« less

Hydrodynamic scaling of the deceleration-phase Rayleigh–Taylor instability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bose, A., E-mail: abos@lle.rochester.edu; Woo, K. M.; Betti, R.

2015-07-15

The scaling of the deceleration phase of inertial fusion direct-drive implosions is investigated for OMEGA and National Ignition Facility (NIF)-size targets. It is shown that the deceleration-phase Rayleigh–Taylor instability (RTI) does not scale hydro-equivalently with implosion size. This is because ablative stabilization resulting from thermal conduction and radiation transport in a spherically converging geometry is different on the two scales. As a consequence, NIF-scale implosions show lower hot-spot density and mass ablation velocity, allowing for higher RTI growth. On the contrary, stabilization resulting from density-gradient enhancement, caused by reabsorption of radiation emitted from the hot spot, is higher on NIFmore » implosions. Since the RTI mitigation related to thermal conduction and radiation transport scale oppositely with implosion size, the degradation of implosion performance caused by the deceleration RTI is similar for NIF and OMEGA targets. It is found that a minimum threshold for the no-α Lawson ignition parameter of χ{sub Ω} ≈ 0.2 at the OMEGA scale is required to demonstrate hydro-equivalent ignition at the NIF scale for symmetric direct-drive implosions.« less

Scope of Work for Integration Management and Installation Services of the National Ignition Facility Beampath Infrastructure System

NASA Astrophysics Data System (ADS)

Coyle, P. D.

2000-03-01

The goal of the National Ignition Facility (NIF) project is to provide an above ground experimental capability for maintaining nuclear competence and weapons effects simulation and to provide a facility capable of achieving fusion ignition using solid-state lasers as the energy driver. The facility will incorporate 192 laser beams, which will be focused onto a small target located at the center of a spherical target chamber-the energy from the laser beams will be deposited in a few billionths of a second. The target will then implode, forcing atomic nuclei to sufficiently high temperatures and densities necessary to achieve a miniature fusion reaction. The NIF is under construction, at Livermore, California, located approximately 50 miles southeast of San Francisco, California. The University of California, Lawrence Livermore National Laboratory (LLNL), operating under Prime Contract W-7405-ENG. 48 with the U.S. Department of Energy (DOE), shall subcontract for Integration Management and Installation (IMI) Services for the Beampath Infrastructure System (BIS). The BIS includes Beampath Hardware and Beampath Utilities. Conventional Facilities work for the NIF Laser and Target Area Building (LTAB) and Optics Assembly Building (OAB) is over 86 percent constructed. This Scope of Work is for Integration Management and Installation (IMI) Services corresponding to Management Services, Design Integration Services, Construction Services, and Commissioning Services for the NIB BIS. The BIS includes Beampath Hardware and Beampath Utilities. Beampath Hardware and Beampath Utilities include beampath vessels, enclosures, and beam tubes; auxiliary and utility systems; and support structures. A substantial amount of GFE will be provided by the University for installation as part of the infrastructure packages.

Initial Findings on Hydrodynamic Scaling Extrapolations of National Ignition Facility BigFoot Implosions

NASA Astrophysics Data System (ADS)

Nora, R.; Field, J. E.; Peterson, J. Luc; Spears, B.; Kruse, M.; Humbird, K.; Gaffney, J.; Springer, P. T.; Brandon, S.; Langer, S.

2017-10-01

We present an experimentally corroborated hydrodynamic extrapolation of several recent BigFoot implosions on the National Ignition Facility. An estimate on the value and error of the hydrodynamic scale necessary for ignition (for each individual BigFoot implosion) is found by hydrodynamically scaling a distribution of multi-dimensional HYDRA simulations whose outputs correspond to their experimental observables. The 11-parameter database of simulations, which include arbitrary drive asymmetries, dopant fractions, hydrodynamic scaling parameters, and surface perturbations due to surrogate tent and fill-tube engineering features, was computed on the TRINITY supercomputer at Los Alamos National Laboratory. This simple extrapolation is the first step in providing a rigorous calibration of our workflow to provide an accurate estimate of the efficacy of achieving ignition on the National Ignition Facility. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

An Experimental Study of Ignition Effects and Flame Growth Over a Thin Solid Fuel in Low-Speed Concurrent Flow Using Drop-Tower Facilities

NASA Technical Reports Server (NTRS)

Pettegrew, Richard Dale

1996-01-01

An experimental study of ignition and flame growth over a thin solid fuel in oxidizer flow speeds from 0 to 10 cm/sec concurrent flow was performed. This study examined the differences between ignition using a resistively heated wire (woven in a sawtooth pattern over the leading edge of the fuel), and a straight resistively heated wire augmented by a chemical ignitor doped onto the leading edge of the fuel. Results showed that the chemical system yielded non-uniform ignition bursts, while the system using only the hotwire gave more uniform ignition. At speeds up to 2.5 cm/sec, the chemical system yielded non-uniform pyrolysis fronts, while the hotwire system gave more uniform pyrolysis fronts. At speeds of 5 cm/sec or greater, both systems gave uniform pyrolysis fronts. The chemically-ignited flames tended to become too dim to see faster than the hotwire-ignited flames, and the flame lengths were observed to be shorter (after the initial burst subsided) for the chemical system for all speeds. Flame and pyrolysis element velocities were measured. Temperature profiles for selected tests were measured using thermocouples at the fuel surface and in the gas phase. Comparisons between the flame element velocities and peak temperatures recorded in these tests with calculated spread rates and peak temperatures from a steady-state model are presented. Agreement was found to be within 20% for most flame elements for nominal velocities of 5 cm/sec and 7.5 cm/sec.

NIF Target Designs and OMEGA Experiments for Shock-Ignition Inertial Confinement Fusion

NASA Astrophysics Data System (ADS)

Anderson, K. S.

2012-10-01

Shock ignition (SI)footnotetextR. Betti et al., Phys. Rev. Lett. 98, 155001 (2007). is being pursued as a viable option to achieve ignition on the National Ignition Facility (NIF). Shock-ignition target designs require the addition of a high-intensity (˜5 x 10^15 W/cm^2) laser spike at the end of a low-adiabat assembly pulse to launch a spherically convergent strong shock to ignite the imploding capsule. Achieving ignition with SI requires the laser spike to generate an ignitor shock with a launching pressure typically in excess of ˜300 Mbar. At the high laser intensities required during the spike pulse, stimulated Raman (SRS) and Brillouin scattering (SBS) could reflect a significant fraction of the incident light. In addition, SRS and the two-plasmon-decay instability can accelerate hot electrons into the shell and preheat the fuel. Since the high-power spike occurs at the end of the pulse when the areal density of the shell is several tens of mg/cm^2, shock-ignition fuel layers are shielded against hot electrons with energies below 150 keV. This paper will present data for a set of OMEGA experiments that were designed to study laser--plasma interactions during the spike pulse. In addition, these experiments were used to demonstrate that high-pressure shocks can be produced in long-scale-length plasmas with SI-relevant intensities. Within the constraints imposed by the hydrodynamics of strong shock generation and the laser--plasma instabilities, target designs for SI experiments on the NIF will be presented. Two-dimensional radiation--hydrodynamic simulations of SI target designs for the NIF predict ignition in the polar-drive beam configuration at sub-MJ laser energies. Design robustness to various 1-D effects and 2-D nonuniformities has been characterized. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-08NA28302.

Theory of hydro-equivalent ignition for inertial fusion and its applications to OMEGA and the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nora, R.; Betti, R.; Bose, A.

The theory of ignition for inertial confinement fusion capsules [R. Betti et al., Phys. Plasmas 17, 058102 (2010)] is used to assess the performance requirements for cryogenic implosion experiments on the Omega Laser Facility. The theory of hydrodynamic similarity is developed in both one and two dimensions and tested using multimode hydrodynamic simulations with the hydrocode DRACO [P. B. Radha et al., Phys. Plasmas 12, 032702 (2005)] of hydro-equivalent implosions (implosions with the same implosion velocity, adiabat, and laser intensity). The theory is used to scale the performance of direct-drive OMEGA implosions to the National Ignition Facility (NIF) energy scalesmore » and determine the requirements for demonstrating hydro-equivalent ignition on OMEGA. Hydro-equivalent ignition on OMEGA is represented by a cryogenic implosion that would scale to ignition on the NIF at 1.8 MJ of laser energy symmetrically illuminating the target. It is found that a reasonable combination of neutron yield and areal density for OMEGA hydro-equivalent ignition is 3 to 6 × 10{sup 13} and ∼0.3 g/cm{sup 2}, respectively, depending on the level of laser imprinting. This performance has not yet been achieved on OMEGA.« less

Combustion chemistry of ethanol: Ignition and speciation studies in a rapid compression facility [On the combustion chemistry of ethanol: Ignition and speciation studies in a rapid compression facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barraza-Botet, Cesar L.; Wagnon, Scott W.; Wooldridge, Margaret S.

Here, ethanol remains the most important alternative fuel for the transportation sector. This work presents new experimental data on ethanol ignition, including stable species measurements, obtained with the University of Michigan rapid compression facility. Ignition delay times were determined from pressure histories of ignition experiments with stoichiometric ethanol–air mixtures at pressures of ~3–10 atm. Temperatures (880–1150 K) were controlled by varying buffer gas composition (Ar, N 2, CO 2). High-speed imaging was used to record chemiluminescence during the experiments, which showed homogeneous ignition events. The results for ignition delay time agreed well with trends on the basis of previous experimentalmore » measurements. Speciation experiments were performed using fast gas sampling and gas chromatography to identify and quantify ethanol and 11 stable intermediate species formed during the ignition delay period. Simulations were carried out using a chemical kinetic mechanism available in the literature, and the agreement with the experimental results for ignition delay time and the intermediate species measured was excellent for the majority of the conditions studied. From the simulation results, ethanol + HO 2 was identified as an important reaction at the experimental conditions for both the ignition delay time and intermediate species measurements. Further studies to improve the accuracy of the rate coefficient for ethanol + HO 2 would improve the predictive understanding of intermediate and low-temperature ethanol combustion.« less

Combustion chemistry of ethanol: Ignition and speciation studies in a rapid compression facility [On the combustion chemistry of ethanol: Ignition and speciation studies in a rapid compression facility

DOE PAGES

Barraza-Botet, Cesar L.; Wagnon, Scott W.; Wooldridge, Margaret S.

2016-08-31

Here, ethanol remains the most important alternative fuel for the transportation sector. This work presents new experimental data on ethanol ignition, including stable species measurements, obtained with the University of Michigan rapid compression facility. Ignition delay times were determined from pressure histories of ignition experiments with stoichiometric ethanol–air mixtures at pressures of ~3–10 atm. Temperatures (880–1150 K) were controlled by varying buffer gas composition (Ar, N 2, CO 2). High-speed imaging was used to record chemiluminescence during the experiments, which showed homogeneous ignition events. The results for ignition delay time agreed well with trends on the basis of previous experimentalmore » measurements. Speciation experiments were performed using fast gas sampling and gas chromatography to identify and quantify ethanol and 11 stable intermediate species formed during the ignition delay period. Simulations were carried out using a chemical kinetic mechanism available in the literature, and the agreement with the experimental results for ignition delay time and the intermediate species measured was excellent for the majority of the conditions studied. From the simulation results, ethanol + HO 2 was identified as an important reaction at the experimental conditions for both the ignition delay time and intermediate species measurements. Further studies to improve the accuracy of the rate coefficient for ethanol + HO 2 would improve the predictive understanding of intermediate and low-temperature ethanol combustion.« less

Test System to Study the Ignition of Metals by Polymers in Oxygen

NASA Technical Reports Server (NTRS)

Shoffstall, Michael S.; Stoltzfus, Joel M.; Fries, Joseph (Technical Monitor)

2000-01-01

A new test system that uses Laser energy to ignite a polymer promoter has been developed at the NASA White Sands Test Facility. It will facilitate the study of the spread of fire from a burning polymer material to the metal surrounding it. The system can be used to answer questions regarding the effects of configuration on ignition and combustion. The data obtained from this test could also be used to develop mathematical models for analyzing the effects of configuration on ignition and combustion. The system features a 10,000-psi (69-MPa) test chamber with sight glass windows on either end and a 25-watt carbon dioxide Laser for an ignition source. The test system can be used with gaseous oxygen, nitrogen or any mixture of the two gases. To minimize the effect of preheating the metallic, the polymer is ignited with a minimal amount of Laser energy. Igniting the polymer in this fashion also simplifies the thermodynamic analysis of the ignition and propagation reactions. The system is very robust, versatile and straightforward to use. Depending on the test pressure and configuration, the test system operator can perform as many as 20 tests per day. Test results verify that ignition and combustion of the metallic sample is not only dependent on pressure, material type and temperature, but configuration of both the polymer promoter and metallic sample. Both 6061 aluminum and 316 stainless steel 0.25-inch (6.35-mm) diameter rods with a standard 0-ring groove were tested with Buna-N, Silicone, Teflon and Viton 0-rings. The system ignited all four types of 0-rings in oxygen at pressures ranging from ambient to 10,000 psi (69 MPa). However, neither the stainless steel nor the aluminum rods on which the O-rings were mounted ignited in any test conditions. Future testing may be done on the 0.25-inch (6.35-mm) rod and O-ring configuration to evaluate the lack of ignition in these tests. Future configurations may include a plug of polymer in the base of the sample and replicas of fire-damaged components. Furthermore, the test system may be used in the future to analyze the oxidation rate of Laser-heated metals in gaseous oxygen.

Direct numerical simulation of auto-ignition of a hydrogen vortex ring reacting with hot air

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doom, Jeff; Mahesh, Krishnan

2009-04-15

Direct numerical simulation (DNS) is used to study chemically reacting, laminar vortex rings. A novel, all-Mach number algorithm developed by Doom et al. [J. Doom, Y. Hou, K. Mahesh, J. Comput. Phys. 226 (2007) 1136-1151] is used. The chemical mechanism is a nine species, nineteen reaction mechanism for H{sub 2}/air combustion proposed by Mueller et al. [M.A. Mueller, T.J. Kim, R.A. Yetter, F.L. Dryer, Int. J. Chem. Kinet. 31 (1999) 113-125]. Diluted H{sub 2} at ambient temperature (300 K) is injected into hot air. The simulations study the effect of fuel/air ratios, oxidizer temperature, Lewis number and stroke ratio (ratiomore » of piston stroke length to diameter). Results show that auto-ignition occurs in fuel lean, high temperature regions with low scalar dissipation at a 'most reactive' mixture fraction, {zeta}{sub MR} (Mastorakos et al. [E. Mastorakos, T.A. Baritaud, T.J. Poinsot, Combust. Flame 109 (1997) 198-223]). Subsequent evolution of the flame is not predicted by {zeta}{sub MR}; a most reactive temperature T{sub MR} is defined and shown to predict both the initial auto-ignition as well as subsequent evolution. For stroke ratios less than the formation number, ignition in general occurs behind the vortex ring and propagates into the core. At higher oxidizer temperatures, ignition is almost instantaneous and occurs along the entire interface between fuel and oxidizer. For stroke ratios greater than the formation number, ignition initially occurs behind the leading vortex ring, then occurs along the length of the trailing column and propagates toward the ring. Lewis number is seen to affect both the initial ignition as well as subsequent flame evolution significantly. Non-uniform Lewis number simulations provide faster ignition and burnout time but a lower maximum temperature. The fuel rich reacting vortex ring provides the highest maximum temperature and the higher oxidizer temperature provides the fastest ignition time. The fuel lean reacting vortex ring has little effect on the flow and behaves similar to a non-reacting vortex ring. (author)« less

01-NIF Dedication: George Miller

ScienceCinema

George Miller

2017-12-09

The National Ignition Facility, the world's largest laser system, was dedicated at a ceremony on May 29, 2009 at Lawrence Livermore National Laboratory. These are the remarks by Lab Director George Miller.

09-NIF Dedication: Arnold Schwarzenegger

DOE Office of Scientific and Technical Information (OSTI.GOV)

Governor Arnold Schwarzenegger

2009-07-02

The National Ignition Facility, the world's largest laser system, was dedicated at a ceremony on May 29, 2009 at Lawrence Livermore National Laboratory. These are the remarks by California Governor Arnold Schwarzenegger.

09-NIF Dedication: Arnold Schwarzenegger

ScienceCinema

Governor Arnold Schwarzenegger

2017-12-09

The National Ignition Facility, the world's largest laser system, was dedicated at a ceremony on May 29, 2009 at Lawrence Livermore National Laboratory. These are the remarks by California Governor Arnold Schwarzenegger.

01-NIF Dedication: George Miller

DOE Office of Scientific and Technical Information (OSTI.GOV)

George Miller

2009-07-02

The National Ignition Facility, the world's largest laser system, was dedicated at a ceremony on May 29, 2009 at Lawrence Livermore National Laboratory. These are the remarks by Lab Director George Miller.

02-NIF Dedication: Edward Moses

ScienceCinema

Edward Moses

2017-12-09

The National Ignition Facility, the world's largest laser system, was dedicated at a ceremony on May 29, 2009 at Lawrence Livermore National Laboratory. These are the remarks by NIF Director Edward Moses.

Capsule performance optimization in the National Ignition Campaigna)

NASA Astrophysics Data System (ADS)

Landen, O. L.; Boehly, T. R.; Bradley, D. K.; Braun, D. G.; Callahan, D. A.; Celliers, P. M.; Collins, G. W.; Dewald, E. L.; Divol, L.; Glenzer, S. H.; Hamza, A.; Hicks, D. G.; Hoffman, N.; Izumi, N.; Jones, O. S.; Kirkwood, R. K.; Kyrala, G. A.; Michel, P.; Milovich, J.; Munro, D. H.; Nikroo, A.; Olson, R. E.; Robey, H. F.; Spears, B. K.; Thomas, C. A.; Weber, S. V.; Wilson, D. C.; Marinak, M. M.; Suter, L. J.; Hammel, B. A.; Meyerhofer, D. D.; Atherton, J.; Edwards, J.; Haan, S. W.; Lindl, J. D.; MacGowan, B. J.; Moses, E. I.

2010-05-01

A capsule performance optimization campaign will be conducted at the National Ignition Facility [G. H. Miller et al., Nucl. Fusion 44, 228 (2004)] to substantially increase the probability of ignition by laser-driven hohlraums [J. D. Lindl et al., Phys. Plasmas 11, 339 (2004)]. The campaign will experimentally correct for residual uncertainties in the implosion and hohlraum physics used in our radiation-hydrodynamic computational models before proceeding to cryogenic-layered implosions and ignition attempts. The required tuning techniques using a variety of ignition capsule surrogates have been demonstrated at the OMEGA facility under scaled hohlraum and capsule conditions relevant to the ignition design and shown to meet the required sensitivity and accuracy. In addition, a roll-up of all expected random and systematic uncertainties in setting the key ignition laser and target parameters due to residual measurement, calibration, cross-coupling, surrogacy, and scale-up errors has been derived that meets the required budget.

Capsule performance optimization in the National Ignition Campaign

DOE Office of Scientific and Technical Information (OSTI.GOV)

Landen, O. L.; Bradley, D. K.; Braun, D. G.

2010-05-15

A capsule performance optimization campaign will be conducted at the National Ignition Facility [G. H. Miller et al., Nucl. Fusion 44, 228 (2004)] to substantially increase the probability of ignition by laser-driven hohlraums [J. D. Lindl et al., Phys. Plasmas 11, 339 (2004)]. The campaign will experimentally correct for residual uncertainties in the implosion and hohlraum physics used in our radiation-hydrodynamic computational models before proceeding to cryogenic-layered implosions and ignition attempts. The required tuning techniques using a variety of ignition capsule surrogates have been demonstrated at the OMEGA facility under scaled hohlraum and capsule conditions relevant to the ignition designmore » and shown to meet the required sensitivity and accuracy. In addition, a roll-up of all expected random and systematic uncertainties in setting the key ignition laser and target parameters due to residual measurement, calibration, cross-coupling, surrogacy, and scale-up errors has been derived that meets the required budget.« less

Shock ignition: a new approach to high gain inertial confinement fusion on the national ignition facility.

PubMed

Perkins, L J; Betti, R; LaFortune, K N; Williams, W H

2009-07-24

Shock ignition, an alternative concept for igniting thermonuclear fuel, is explored as a new approach to high gain, inertial confinement fusion targets for the National Ignition Facility (NIF). Results indicate thermonuclear yields of approximately 120-250 MJ may be possible with laser drive energies of 1-1.6 MJ, while gains of approximately 50 may still be achievable at only approximately 0.2 MJ drive energy. The scaling of NIF energy gain with laser energy is found to be G approximately 126E (MJ);{0.510}. This offers the potential for high-gain targets that may lead to smaller, more economic fusion power reactors and a cheaper fusion energy development path.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edward Moses

The National Ignition Facility, the world's largest laser system, was dedicated at a ceremony on May 29, 2009 at Lawrence Livermore National Laboratory. These are the concluding remarks by NIF Director Edward Moses, and a brief video presentation.

A low cost igniter utilizing an SCB and titanium sub-hydride potassium perchlorate pyrotechnic

NASA Technical Reports Server (NTRS)

Bickes, R. W., Jr.; Grubelich, M. C.; Hartman, J. K.; McCampbell, C. B.; Churchill, J. K.

1994-01-01

A conventional NSI (NASA Standard Initiator) normally employs a hot-wire ignition element to ignite ZPP (zirconium potassium perchlorate). With minor modifications to the interior of a header similar to an NSI device to accommodate an SCB (semiconductor bridge), a low cost initiator was obtained. In addition, the ZPP was replaced with THKP (titanium sub-hydride potassium perchlorate) to obtain increased overall gas production and reduced static-charge sensitivity. This paper reports on the all-fire and no-fire levels obtained and on a dual mix device that uses THKP as the igniter mix and a thermite as the output mix.

The design of the optical Thomson scattering diagnostic for the National Ignition Facility [The preliminary design of the optical Thomson scattering diagnostic for the National Ignition Facility

DOE PAGES

Datte, P. S.; Ross, J. S.; Froula, D. H.; ...

2016-09-21

Here, the National Ignition Facility (NIF) is a 192 laser beam facility designed to support the Stockpile Stewardship, High Energy Density and Inertial Confinement Fusion (ICF) programs. We report on the design of an Optical Thomson Scattering (OTS) diagnostic that has the potential to transform the community’s understanding of NIF hohlraum physics by providing first principle, local, time-resolved measurements of under-dense plasma conditions. The system design allows operation with different probe laser wavelengths by manual selection of the appropriate beam splitter and gratings before the shot. A deep-UV probe beam (λ 0-210 nm) will be used to optimize the scatteredmore » signal for plasma densities of 5 × 10 20 electrons/cm 3 while a 3ω probe will be used for experiments investigating lower density plasmas of 1 × 10 19 electrons/cm 3. We report the phase I design of a two phase design strategy. Phase I includes the OTS telescope, spectrometer, and streak camera; these will be used to assess the background levels at NIF. Phase II will include the design and installation of a probe laser.« less

The design of the optical Thomson scattering diagnostic for the National Ignition Facility [The preliminary design of the optical Thomson scattering diagnostic for the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Datte, P. S.; Ross, J. S.; Froula, D. H.

Here, the National Ignition Facility (NIF) is a 192 laser beam facility designed to support the Stockpile Stewardship, High Energy Density and Inertial Confinement Fusion (ICF) programs. We report on the design of an Optical Thomson Scattering (OTS) diagnostic that has the potential to transform the community’s understanding of NIF hohlraum physics by providing first principle, local, time-resolved measurements of under-dense plasma conditions. The system design allows operation with different probe laser wavelengths by manual selection of the appropriate beam splitter and gratings before the shot. A deep-UV probe beam (λ 0-210 nm) will be used to optimize the scatteredmore » signal for plasma densities of 5 × 10 20 electrons/cm 3 while a 3ω probe will be used for experiments investigating lower density plasmas of 1 × 10 19 electrons/cm 3. We report the phase I design of a two phase design strategy. Phase I includes the OTS telescope, spectrometer, and streak camera; these will be used to assess the background levels at NIF. Phase II will include the design and installation of a probe laser.« less

Guide for Oxygen Compatibility Assessments on Oxygen Components and Systems

NASA Technical Reports Server (NTRS)

Rosales, Keisa R.; Shoffstall, Michael S.; Stoltzfus, Joel M.

2007-01-01

Understanding and preventing fire hazards is necessary when designing, maintaining, and operating oxygen systems. Ignition risks can be minimized by controlling heat sources and using materials that will not ignite or will not support burning in the end-use environment. Because certain materials are more susceptible to ignition in oxygen-enriched environments, a compatibility assessment should be performed before the component is introduced into an oxygen system. This document provides an overview of oxygen fire hazards and procedures that are consistent with the latest versions of American Society for Testing and Materials (ASTM) Standards G63 (1999) and G94 (2005) to address fire hazards associated with oxygen systems. This document supersedes the previous edition, NASA Technical Memorandum 104823, Guide for Oxygen Hazards Analyses on Components and Systems (1996). The step-by-step oxygen compatibility assessment method described herein (see Section 4) enables oxygen-system designers, system engineers, and facility managers to determine areas of concern with respect to oxygen compatibility and, ultimately, prevent damage to a system or injury to personnel.

Users' guide to new approaches and sanctions for multiple DWI offenders

DOT National Transportation Integrated Search

1989-12-01

This guide describes nine new approaches for reducing recidivism among multiple DWI offenders: dedicated detention facilities, diversion programs, electronic monitoring, ignition interlock systems, intensive probation supervision, publishing offender...

33 CFR 127.1605 - Other sources of ignition.

Code of Federal Regulations, 2011 CFR

2011-07-01

... sources of ignition. Each operator of a waterfront facility handling LHG shall ensure that in the marine... is located where sparks may ignite combustible material; and (d) All rubbish, debris, and waste go...

Consider the DME alternative for diesel engines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fleisch, T.H.; Meurer, P.C.

1996-07-01

Engine tests demonstrate that dimethyl ether (DME, CH{sub 3}OCH{sub 3}) can provide an alternative approach toward efficient, ultra-clean and quiet compression ignition (CI) engines. From a combustion point of view, DME is an attractive alternative fuel for CI engines, primarily for commercial applications in urban areas, where ultra-low emissions will be required in the future. DME can resolve the classical diesel emission problem of smoke emissions, which are completely eliminated. With a properly developed DME injection and combustion system, NO{sub x} emissions can be reduced to 40% of Euro II or U.S. 1998 limits, and can meet the future ULEVmore » standards of California. Simultaneously, the combustion noise is reduced by as much as 15 dB(A) below diesel levels. In addition, the classical diesel advantages such as high thermal efficiency, compression ignition, engine robustness, etc., are retained.« less

High Pressure Quick Disconnect Particle Impact Tests

NASA Technical Reports Server (NTRS)

Rosales, Keisa R.; Stoltzfus, Joel M.

2009-01-01

NASA Johnson Space Center White Sands Test Facility (WSTF) performed particle impact testing to determine whether there is a particle impact ignition hazard in the quick disconnects (QDs) in the Environmental Control and Life Support System (ECLSS) on the International Space Station (ISS). Testing included standard supersonic and subsonic particle impact tests on 15-5 PH stainless steel, as well as tests performed on a QD simulator. This paper summarizes the particle impact tests completed at WSTF. Although there was an ignition in Test Series 4, it was determined the ignition was caused by the presence of a machining imperfection. The sum of all the test results indicates that there is no particle impact ignition hazard in the ISS ECLSS QDs. KEYWORDS: quick disconnect, high pressure, particle impact testing, stainless steel

High Pressure Quick Disconnect Particle Impact Tests

NASA Technical Reports Server (NTRS)

Peralta, Stephen; Rosales, Keisa; Smith, Sarah R.; Stoltzfus, Joel M.

2007-01-01

To determine whether there is a particle impact ignition hazard in the quick disconnects (QDs) in the Environmental Control and Life Support System (ECLSS) on the International Space Station (ISS), NASA Johnson Space Center requested White Sands Test Facility (WSTF) to perform particle impact testing. Testing was performed from November 2006 through May 2007 and included standard supersonic and subsonic particle impact tests on 15-5 PH stainless steel, as well as tests performed on a QD simulator. This report summarizes the particle impact tests completed at WSTF. Although there was an ignition in Test Series 4, it was determined the ignition was caused by the presence of a machining imperfection. The sum of all the test results indicates that there is no particle impact ignition hazard in the ISS ECLSS QDs.

The first experiments on the national ignition facility

NASA Astrophysics Data System (ADS)

Landen, O. L.; Glenzer, S.; Froula, D.; Dewald, E.; Suter, L. J.; Schneider, M.; Hinkel, D.; Fernandez, J.; Kline, J.; Goldman, S.; Braun, D.; Celliers, P.; Moon, S.; Robey, H.; Lanier, N.; Glendinning, G.; Blue, B.; Wilde, B.; Jones, O.; Schein, J.; Divol, L.; Kalantar, D.; Campbell, K.; Holder, J.; McDonald, J.; Niemann, C.; MacKinnon, A.; Collins, R.; Bradley, D.; Eggert, J.; Hicks, D.; Gregori, G.; Kirkwood, R.; Niemann, C.; Young, B.; Foster, J.; Hansen, F.; Perry, T.; Munro, D.; Baldis, H.; Grim, G.; Heeter, R.; Hegelich, B.; Montgomery, D.; Rochau, G.; Olson, R.; Turner, R.; Workman, J.; Berger, R.; Cohen, B.; Kruer, W.; Langdon, B.; Langer, S.; Meezan, N.; Rose, H.; Still, B.; Williams, E.; Dodd, E.; Edwards, J.; Monteil, M.-C.; Stevenson, M.; Thomas, B.; Coker, R.; Magelssen, G.; Rosen, P.; Stry, P.; Woods, D.; Weber, S.; Alvarez, S.; Armstrong, G.; Bahr, R.; Bourgade, J.-L.; Bower, D.; Celeste, J.; Chrisp, M.; Compton, S.; Cox, J.; Constantin, C.; Costa, R.; Duncan, J.; Ellis, A.; Emig, J.; Gautier, C.; Greenwood, A.; Griffith, R.; Holdner, F.; Holtmeier, G.; Hargrove, D.; James, T.; Kamperschroer, J.; Kimbrough, J.; Landon, M.; Lee, D.; Malone, R.; May, M.; Montelongo, S.; Moody, J.; Ng, E.; Nikitin, A.; Pellinen, D.; Piston, K.; Poole, M.; Rekow, V.; Rhodes, M.; Shepherd, R.; Shiromizu, S.; Voloshin, D.; Warrick, A.; Watts, P.; Weber, F.; Young, P.; Arnold, P.; Atherton, L.; Bardsley, G.; Bonanno, R.; Borger, T.; Bowers, M.; Bryant, R.; Buckman, S.; Burkhart, S.; Cooper, F.; Dixit, S.; Erbert, G.; Eder, D.; Ehrlich, B.; Felker, B.; Fornes, J.; Frieders, G.; Gardner, S.; Gates, C.; Gonzalez, M.; Grace, S.; Hall, T.; Haynam, C.; Heestand, G.; Henesian, M.; Hermann, M.; Hermes, G.; Huber, S.; Jancaitis, K.; Johnson, S.; Kauffman, B.; Kelleher, T.; Kohut, T.; Koniges, A. E.; Labiak, T.; Latray, D.; Lee, A.; Lund, D.; Mahavandi, S.; Manes, K. R.; Marshall, C.; McBride, J.; McCarville, T.; McGrew, L.; Menapace, J.; Mertens, E.; Munro, D.; Murray, J.; Neumann, J.; Newton, M.; Opsahl, P.; Padilla, E.; Parham, T.; Parrish, G.; Petty, C.; Polk, M.; Powell, C.; Reinbachs, I.; Rinnert, R.; Riordan, B.; Ross, G.; Robert, V.; Tobin, M.; Sailors, S.; Saunders, R.; Schmitt, M.; Shaw, M.; Singh, M.; Spaeth, M.; Stephens, A.; Tietbohl, G.; Tuck, J.; van Wonterghem, B.; Vidal, R.; Wegner, P.; Whitman, P.; Williams, K.; Winward, K.; Work, K.; Wallace, R.; Nobile, A.; Bono, M.; Day, B.; Elliott, J.; Hatch, D.; Louis, H.; Manzenares, R.; O'Brien, D.; Papin, P.; Pierce, T.; Rivera, G.; Ruppe, J.; Sandoval, D.; Schmidt, D.; Valdez, L.; Zapata, K.; MacGowan, B.; Eckart, M.; Hsing, W.; Springer, P.; Hammel, B.; Moses, E.; Miller, G.

2006-06-01

A first set of shock propagation, laser-plasma interaction, hohlraum energetics and hydrodynamic experiments have been performed using the first 4 beams of the National Ignition Facility (NIF), in support of indirect drive Inertial Confinement Fusion (ICF) and High Energy Density Physics.

Novel Characterization of Capsule X-Ray Drive at the National Ignition Facility [Using ViewFactor Experiments to Measure Hohlraum X-Radiation Drive from the Capsule Point-of-View in Ignition Experiments on the National Ignition Facility

DOE PAGES

MacLaren, S. A.; Schneider, M. B.; Widmann, K.; ...

2014-03-13

Here, indirect drive experiments at the National Ignition Facility are designed to achieve fusion by imploding a fuel capsule with x rays from a laser-driven hohlraum. Previous experiments have been unable to determine whether a deficit in measured ablator implosion velocity relative to simulations is due to inadequate models of the hohlraum or ablator physics. ViewFactor experiments allow for the first time a direct measure of the x-ray drive from the capsule point of view. The experiments show a 15%–25% deficit relative to simulations and thus explain nearly all of the disagreement with the velocity data. In addition, the datamore » from this open geometry provide much greater constraints on a predictive model of laser-driven hohlraum performance than the nominal ignition target.« less

Fill-Tube-Induced Mass Perturbations on X-Ray-Driven, Ignition-Scale, Inertial-Confinement-Fusion Capsule Shells and the Implications for Ignition Experiments

DOE PAGES

Bennett, G. R.; Herrmann, M. C.; Edwards, M. J.; ...

2007-11-13

We present on the first inertial-confinement-fusion ignition facility, the target capsule will be DT filled through a long, narrow tube inserted into the shell. μg-scale shell perturbations Δm' arising from multiple, 10–50 μm-diameter, hollow SiO 2 tubes on x-ray-driven, ignition-scale, 1-mg capsules have been measured on a subignition device. Finally, simulations compare well with observation, whence it is corroborated that Δm' arises from early x-ray shadowing by the tube rather than tube mass coupling to the shell, and inferred that 10–20 μm tubes will negligibly affect fusion yield on a full-ignition facility.

08-NIF Dedication: Zoe Lofgren

ScienceCinema

Congresswoman Zoe Lofgren

2017-12-09

The National Ignition Facility, the world's largest laser system, was dedicated at a ceremony on May 29, 2009 at Lawrence Livermore National Laboratory. These are the remarks by Congresswoman Zoe Lofgren, of California's 16th district.

11-NIF Dedication: Dianne Feinstein

ScienceCinema

U.S. Senator Dianne Feinstein

2017-12-09

The National Ignition Facility, the world's largest laser system, was dedicated at a ceremony on May 29, 2009 at Lawrence Livermore National Laboratory. These are the remarks by U.S. Senator Dianne Feinstein of California.

08-NIF Dedication: Zoe Lofgren

DOE Office of Scientific and Technical Information (OSTI.GOV)

Congresswoman Zoe Lofgren

2009-07-02

The National Ignition Facility, the world's largest laser system, was dedicated at a ceremony on May 29, 2009 at Lawrence Livermore National Laboratory. These are the remarks by Congresswoman Zoe Lofgren, of California's 16th district.

11-NIF Dedication: Dianne Feinstein

DOE Office of Scientific and Technical Information (OSTI.GOV)

U.S. Senator Dianne Feinstein

2009-07-02

The National Ignition Facility, the world's largest laser system, was dedicated at a ceremony on May 29, 2009 at Lawrence Livermore National Laboratory. These are the remarks by U.S. Senator Dianne Feinstein of California.

X-ray transport and radiation response assessment (XTRRA) experiments at the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fournier, K. B., E-mail: fournier2@llnl.gov; Brown, C. G.; Yeoman, M. F.

2016-11-15

Our team has developed an experimental platform to evaluate the x-ray-generated stress and impulse in materials. Experimental activities include x-ray source development, design of the sample mounting hardware and sensors interfaced to the National Ignition Facility’s diagnostics insertion system, and system integration into the facility. This paper focuses on the X-ray Transport and Radiation Response Assessment (XTRRA) test cassettes built for these experiments. The test cassette is designed to position six samples at three predetermined distances from the source, each known to within ±1% accuracy. Built-in calorimeters give in situ measurements of the x-ray environment along the sample lines ofmore » sight. The measured accuracy of sample responses as well as planned modifications to the XTRRA cassette is discussed.« less

Managing NIF safety equipment in a high neutron and gamma radiation environment.

PubMed

Datte, Philip; Eckart, Mark; Jackson, Mark; Khater, Hesham; Manuel, Stacie; Newton, Mark

2013-06-01

The National Ignition Facility (NIF) is a 192 laser beam facility that supports the Inertial Confinement Fusion program. During the ignition experimental campaign, the NIF is expected to perform shots with varying fusion yield producing 14 MeV neutrons up to 20 MJ or 7.1 × 10(18) neutrons per shot and a maximum annual yield of 1,200 MJ. Several infrastructure support systems will be exposed to varying high yield shots over the facility's 30-y life span. In response to this potential exposure, analysis and testing of several facility safety systems have been conducted. A detailed MCNP (Monte Carlo N-Particle Transport Code) model has been developed for the NIF facility, and it includes most of the major structures inside the Target Bay. The model has been used in the simulation of expected neutron and gamma fluences throughout the Target Bay. Radiation susceptible components were identified and tested to fluences greater than 10(13) (n cm(-2)) for 14 MeV neutrons and γ-ray equivalent. The testing includes component irradiation using a 60Co gamma source and accelerator-based irradiation using 4- and 14- MeV neutron sources. The subsystem implementation in the facility is based on the fluence estimates after shielding and survivability guidelines derived from the dose maps and component tests results. This paper reports on the evaluation and implementation of mitigations for several infrastructure safety support systems, including video, oxygen monitoring, pressure monitors, water sensing systems, and access control interfaces found at the NIF.

National Ignition Facility: Experimental plan

NASA Astrophysics Data System (ADS)

1994-05-01

As part of the Conceptual Design Report (CDR) for the National Ignition Facility (NIF), scientists from Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), Sandia National Laboratory (SNL), the University of Rochester's Laboratory for Laser Energetics (UR/LLE), and EG&G formed an NIF Target Diagnostics Working Group. The purpose of the Target Diagnostics Working Group is to prepare conceptual designs of target diagnostics for inclusion in the facility CDR and to determine how these specifications impact the CDR. To accomplish this, a subgroup has directed its efforts at constructing an approximate experimental plan for the ignition campaign of the NIF CDR. The results of this effort are contained in this document, the Experimental Plan for achieving fusion ignition in the NIF. This group initially concentrated on the flow-down requirements of the experimental campaign leading to ignition, which will dominate the initial efforts of the NIF. It is envisaged, however, that before ignition, there will be parallel campaigns supporting weapons physics, weapons effects, and other research. This plan was developed by analyzing the sequence of activities required to finally fire the laser at the level of power and precision necessary to achieve the conditions of an ignition hohlraum target, and to then use our experience in activating and running Nova experiments to estimate the rate of completing these activities.

Combustion and operating characteristics of spark-ignition engines

NASA Technical Reports Server (NTRS)

Heywood, J. B.; Keck, J. C.; Beretta, G. P.; Watts, P. A.

1980-01-01

The spark-ignition engine turbulent flame propagation process was investigated. Then, using a spark-ignition engine cycle simulation and combustion model, the impact of turbocharging and heat transfer variations or engine power, efficiency, and NO sub x emissions was examined.

Final Report - Low Temperature Combustion Chemistry And Fuel Component Interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wooldridge, Margaret

Recent research into combustion chemistry has shown that reactions at “low temperatures” (700 – 1100 K) have a dramatic influence on ignition and combustion of fuels in virtually every practical combustion system. A powerful class of laboratory-scale experimental facilities that can focus on fuel chemistry in this temperature range is the rapid compression facility (RCF), which has proven to be a versatile tool to examine the details of fuel chemistry in this important regime. An RCF was used in this project to advance our understanding of low temperature chemistry of important fuel compounds. We show how factors including fuel molecularmore » structure, the presence of unsaturated C=C bonds, and the presence of alkyl ester groups influence fuel auto-ignition and produce variable amounts of negative temperature coefficient behavior of fuel ignition. We report new discoveries of synergistic ignition interactions between alkane and alcohol fuels, with both experimental and kinetic modeling studies of these complex interactions. The results of this project quantify the effects of molecular structure on combustion chemistry including carbon bond saturation, through low temperature experimental studies of esters, alkanes, alkenes, and alcohols.« less

Impacts assessment for the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bay Area Economics

1996-12-01

This report documents the economic and other impacts that will be created by the National Ignition Facility (NIF) construction and ongoing operation, as well as the impacts that may be created by new technologies that may be developed as a result of NIF development and operation.

Evaluation of the Revolver Ignition Design at the National Ignition Facility Using Polar-Direct-Drive Illumination

NASA Astrophysics Data System (ADS)

McKenty, P. W.; Collins, T. J. B.; Marozas, J. A.; Campbell, E. M.; Molvig, K.; Schmitt, M.

2017-10-01

The direct-drive ignition design Revolver employs a triple-shell target using a beryllium ablator, a copper driver, and an eventual gold pusher. Symmetric numerical calculations indicate that each of the three shells exhibit low convergence ( 3to 5) resulting in a modest gain (G 4) for 1.7 MJ of incident laser energy. Studies are now underway to evaluate the robustness of this design employing polar direct drive (PDD) at the National Ignition Facility. Integral to these calculations is the leveraging of illumination conditioning afforded by research done to demonstrate ignition for a traditional PDD hot-spot target design. Two-dimensional simulation results, employing nonlocal electron-thermal transport and cross-beam energy transport, will be presented that indicate ignition using PDD. A study of the allowed levels of long-wavelength perturbations (target offset and power imbalance) not precluding ignition will also be examined. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

Detecting fiducials affected by trombone delay in ARC and the main laser alignment at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Awwal, Abdul A. S.; Bliss, Erlan S.; Miller Kamm, Victoria; Leach, Richard R.; Roberts, Randy; Rushford, Michael C.; Lowe-Webb, Roger; Wilhelmsen, Karl

2015-09-01

Four of the 192 beams of the National Ignition Facility (NIF) are currently being diverted into the Advanced Radiographic Capability (ARC) system to generate a sequence of short (1-50 picoseconds) 1053 nm laser pulses. When focused onto high Z wires in vacuum, these pulses create high energy x-ray pulses capable of penetrating the dense, imploding fusion fuel plasma during ignition scale experiments. The transmitted x-rays imaged with x-ray diagnostics can create movie radiographs that are expected to provide unprecedented insight into the implosion dynamics. The resulting images will serve as a diagnostic for tuning the experimental parameters towards successful fusion reactions. Beam delays introduced into the ARC pulses via independent, free-space optical trombones create the desired x-ray image sequence, or movie. However, these beam delays cause optical distortion of various alignment fiducials viewed by alignment sensors in the NIF and ARC beamlines. This work describes how the position of circular alignment fiducials is estimated in the presence of distortion.

Star Power on Earth: Path to Clean Energy Future

ScienceCinema

Ed Moses

2017-12-09

Lawrence Livermore National Laboratory's "Science on Saturday" lecture series presents Ed Moses, Director of the National Ignition Facility, discussing the world's largest laser system and its potential impact on society's upcoming energy needs.

Activation Energy of Tantalum-Tungsten Oxide Thermite Reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cervantes, O; Kuntz, J; Gash, A

2010-02-25

The activation energy of a high melting temperature sol-gel (SG) derived tantalum-tungsten oxide thermite composite was determined using the Kissinger isoconversion method. The SG derived powder was consolidated using the High Pressure Spark Plasma Sintering (HPSPS) technique to 300 and 400 C to produce pellets with dimensions of 5 mm diameter by 1.5 mm height. A custom built ignition setup was developed to measure ignition temperatures at high heating rates (500-2000 C {center_dot} min{sup -1}). Such heating rates were required in order to ignite the thermite composite. Unlike the 400 C samples, results show that the samples consolidated to 300more » C undergo an abrupt change in temperature response prior to ignition. This change in temperature response has been attributed to the crystallization of the amorphous WO{sub 3} in the SG derived Ta-WO{sub 3} thermite composite and not to a pre-ignition reaction between the constituents. Ignition temperatures for the Ta-WO{sub 3} thermite ranged from approximately 465-670 C. The activation energy of the SG derived Ta-WO{sup 3} thermite composite consolidated to 300 and 400 C were determined to be 37.787 {+-} 1.58 kJ {center_dot} mol{sup -1} and 57.381 {+-} 2.26 kJ {center_dot} mol{sup -1}, respectively.« less

Investigation of ion kinetic effects in direct-drive exploding-pusher implosions at the NIF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosenberg, M. J., E-mail: mrosenbe@mit.edu; Zylstra, A. B.; Séguin, F. H.

Measurements of yield, ion temperature, areal density (ρR), shell convergence, and bang time have been obtained in shock-driven, D{sub 2} and D{sup 3}He gas-filled “exploding-pusher” inertial confinement fusion (ICF) implosions at the National Ignition Facility to assess the impact of ion kinetic effects. These measurements probed the shock convergence phase of ICF implosions, a critical stage in hot-spot ignition experiments. The data complement previous studies of kinetic effects in shock-driven implosions. Ion temperature and fuel ρR inferred from fusion-product spectroscopy are used to estimate the ion-ion mean free path in the gas. A trend of decreasing yields relative to themore » predictions of 2D DRACO hydrodynamics simulations with increasing Knudsen number (the ratio of ion-ion mean free path to minimum shell radius) suggests that ion kinetic effects are increasingly impacting the hot fuel region, in general agreement with previous results. The long mean free path conditions giving rise to ion kinetic effects in the gas are often prevalent during the shock phase of both exploding pushers and ablatively driven implosions, including ignition-relevant implosions.« less

Two-Dimensional Simulations of Electron Shock Ignition at the Megajoule Scale

NASA Astrophysics Data System (ADS)

Shang, W.; Betti, R.

2016-10-01

Shock ignition uses a late strong shock to ignite the hot spot of an inertial confinement fusion capsule. In the standard shock-ignition scheme, an ignitor shock is launched by the ablation pressure from a spike in laser intensity. Recent experiments on OMEGA have shown that focused beams with intensity up to 6 ×1015 W /cm2 can produce copious amounts of hot electrons. The hot electrons are produced by laser-plasma instabilities (LPI's) and can carry up to 15 % of the instantaneous laser power. Megajoule-scale targets will likely produce even more hot electrons because of the large plasma scale length. We show that it is possible to design ignition targets with low implosion velocities that can be shock ignited using LPI-generated hot electrons to obtain high energy gains. These designs are robust to low-mode asymmetries and they ignite even for highly distorted implosions. Electron shock ignition requires tens of kilojoules of hot electrons, which can only be produced on a large laser facility like the National Ignition Facility. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

Upgrade of the MIT Linear Electrostatic Ion Accelerator (LEIA) for nuclear diagnostics development for Omega, Z and the NIF.

PubMed

Sinenian, N; Manuel, M J-E; Zylstra, A B; Rosenberg, M; Waugh, C J; Rinderknecht, H G; Casey, D T; Sio, H; Ruszczynski, J K; Zhou, L; Gatu Johnson, M; Frenje, J A; Séguin, F H; Li, C K; Petrasso, R D; Ruiz, C L; Leeper, R J

2012-04-01

The MIT Linear Electrostatic Ion Accelerator (LEIA) generates DD and D(3)He fusion products for the development of nuclear diagnostics for Omega, Z, and the National Ignition Facility (NIF). Significant improvements to the system in recent years are presented. Fusion reaction rates, as high as 10(7) s(-1) and 10(6) s(-1) for DD and D(3)He, respectively, are now well regulated with a new ion source and electronic gas control system. Charged fusion products are more accurately characterized, which allows for better calibration of existing nuclear diagnostics. In addition, in situ measurements of the on-target beam profile, made with a CCD camera, are used to determine the metrology of the fusion-product source for particle-counting applications. Finally, neutron diagnostics development has been facilitated by detailed Monte Carlo N-Particle Transport (MCNP) modeling of neutrons in the accelerator target chamber, which is used to correct for scattering within the system. These recent improvements have resulted in a versatile platform, which continues to support the existing nuclear diagnostics while simultaneously facilitating the development of new diagnostics in aid of the National Ignition Campaign at the National Ignition Facility. © 2012 American Institute of Physics

Upgrade of the MIT Linear Electrostatic Ion Accelerator (LEIA) for nuclear diagnostics development for Omega, Z and the NIF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sinenian, N.; Manuel, M. J.-E.; Zylstra, A. B.

2012-04-15

The MIT Linear Electrostatic Ion Accelerator (LEIA) generates DD and D{sup 3}He fusion products for the development of nuclear diagnostics for Omega, Z, and the National Ignition Facility (NIF). Significant improvements to the system in recent years are presented. Fusion reaction rates, as high as 10{sup 7} s{sup -1} and 10{sup 6} s{sup -1} for DD and D{sup 3}He, respectively, are now well regulated with a new ion source and electronic gas control system. Charged fusion products are more accurately characterized, which allows for better calibration of existing nuclear diagnostics. In addition, in situ measurements of the on-target beam profile,more » made with a CCD camera, are used to determine the metrology of the fusion-product source for particle-counting applications. Finally, neutron diagnostics development has been facilitated by detailed Monte Carlo N-Particle Transport (MCNP) modeling of neutrons in the accelerator target chamber, which is used to correct for scattering within the system. These recent improvements have resulted in a versatile platform, which continues to support the existing nuclear diagnostics while simultaneously facilitating the development of new diagnostics in aid of the National Ignition Campaign at the National Ignition Facility.« less

Credit BG. View shows the north and west facades of ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Credit BG. View shows the north and west facades of the building as seen when looking east southeast (124°). Igniters for solid rocket motors were built and tested here. This building was rated for a maximum of 20 pounds (9.1 Kg) of class 1.1 materials and four personnel. Note the lightning rods on roof corners and the exterior electrical system - Jet Propulsion Laboratory Edwards Facility, Igniter Laboratory, Edwards Air Force Base, Boron, Kern County, CA

Development of a short duration backlit pinhole for radiography on the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huntington, C. M.; Krauland, C. M.; Kuranz, C. C.

2010-10-15

Experiments on the National Ignition Facility (NIF) will require bright, short duration, near-monochromatic x-ray backlighters for radiographic diagnosis of many high-energy density systems. This paper details a vanadium pinhole backlighter producing (1.8{+-}0.5)x10{sup 15} x-ray photons into 4{pi} sr near the vanadium He-like characteristic x-ray energy of 5.18 keV. The x-ray yield was quantified from a set of Ross filters imaged to a calibrated image plate, with the Dante diagnostic used to confirm the quasimonochromatic nature of the spectrum produced. Additionally, an x-ray film image shows a source-limited image resolution of 26 {mu}m from a 20 {mu}m diameter pinhole.

High energy chemical laser system

DOEpatents

Gregg, D.W.; Pearson, R.K.

1975-12-23

A high energy chemical laser system is described wherein explosive gaseous mixtures of a reducing agent providing hydrogen isotopes and interhalogen compounds are uniformly ignited by means of an electrical discharge, flash- photolysis or an electron beam. The resulting chemical explosion pumps a lasing chemical species, hydrogen fluoride or deuterium fluoride which is formed in the chemical reaction. The generated lasing pulse has light frequencies in the 3- micron range. Suitable interhalogen compounds include bromine trifluoride (BrF$sub 3$), bromine pentafluoride (BrF$sub 5$), chlorine monofluoride (ClF), chlorine trifluoride (ClF$sub 3$), chlorine pentafluoride (ClF$sub 5$), iodine pentafluoride (IF$sub 5$), and iodine heptafluoride (IF$sub 7$); and suitable reducing agents include hydrogen (H$sub 2$), hydrocarbons such as methane (CH$sub 4$), deuterium (D$sub 2$), and diborane (B$sub 2$H$sub 6$), as well as combinations of the gaseous compound and/or molecular mixtures of the reducing agent.

40 CFR 270.305 - What tank information must I keep at my facility?

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) SOLID WASTES (CONTINUED) EPA ADMINISTERED PERMIT PROGRAMS: THE HAZARDOUS WASTE PERMIT PROGRAM... 267.198. (j) For tank systems in which ignitable, reactive, or incompatible wastes are to be stored or...

10-NIF Dedication: Ellen Tauscher

DOE Office of Scientific and Technical Information (OSTI.GOV)

Congresswoman Ellen Tauscher

2009-07-02

The National Ignition Facility, the world's largest laser system, was dedicated at a ceremony on May 29, 2009 at Lawrence Livermore National Laboratory. These are the remarks by Congresswoman Ellen Tauscher, of California's 10th district, which includes Livermore.

12-NIF Dedication: Concluding remarks and video

ScienceCinema

Edward Moses

2017-12-09

The National Ignition Facility, the world's largest laser system, was dedicated at a ceremony on May 29, 2009 at Lawrence Livermore National Laboratory. These are the concluding remarks by NIF Director Edward Moses, and a brief video presentation.

10-NIF Dedication: Ellen Tauscher

ScienceCinema

Congresswoman Ellen Tauscher

2017-12-09

The National Ignition Facility, the world's largest laser system, was dedicated at a ceremony on May 29, 2009 at Lawrence Livermore National Laboratory. These are the remarks by Congresswoman Ellen Tauscher, of California's 10th district, which includes Livermore.

Progress in Direct-Drive Inertial Confinement Fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCrory, R.L.; Meyerhofer, D.D.; Betti, R.

Significant progress in direct-drive inertial confinement fusion (ICF) research has been made since the completion of the 60-beam, 30-kJ UV OMEGA Laser System [T. R. Boehly, Opt. Commun. 133, 495 (1997)] in 1995. A theory of ignition requirements, applicable to any ICF concept, has been developed. Detailed understanding of laser-plasma coupling, electron thermal transport, and hot-electron preheating has lead to the measurement of neutron-averaged areal densities of ~200 mg/cm^2 in cryogenic target implosions. These correspond to an estimated peak fuel density in excess of 100 g/cm^3 and are in good agreement with hydrodynamic simulations. The implosions were performed using anmore » 18-kJ drive pulse designed to put the converging fuel on an adiabat of two. The polar-drive concept will allow direct-drive-ignition research on the National Ignition Facility while it is configured for indirect drive. Advanced ICF ignition concepts—fast ignition [Tabak et al., Phys. Plasmas 1, 1626 (1994)] and shock ignition [R. Betti et al., Phys. Rev. Lett. 98, 155001 (2007)]—have the potential to significantly reduce ignition driver energies and/or provide higher target gain.« less

Recent advances in automatic alignment system for the National Ignition Facility

NASA Astrophysics Data System (ADS)

Wilhelmsen, Karl; Awwal, Abdul A. S.; Kalantar, Dan; Leach, Richard; Lowe-Webb, Roger; McGuigan, David; Miller Kamm, Vicki

2011-03-01

The automatic alignment system for the National Ignition Facility (NIF) is a large-scale parallel system that directs all 192 laser beams along the 300-m optical path to a 50-micron focus at target chamber in less than 50 minutes. The system automatically commands 9,000 stepping motors to adjust mirrors and other optics based upon images acquired from high-resolution digital cameras viewing beams at various locations. Forty-five control loops per beamline request image processing services running on a LINUX cluster to analyze these images of the beams and references, and automatically steer the beams toward the target. This paper discusses the upgrades to the NIF automatic alignment system to handle new alignment needs and evolving requirements as related to various types of experiments performed. As NIF becomes a continuously-operated system and more experiments are performed, performance monitoring is increasingly important for maintenance and commissioning work. Data, collected during operations, is analyzed for tuning of the laser and targeting maintenance work. Handling evolving alignment and maintenance needs is expected for the planned 30-year operational life of NIF.

Liquid Oxygen/Liquid Methane Test Summary of the RS-18 Lunar Ascent Engine at Simulated Altitude Conditions at NASA White Sands Test Facility

NASA Technical Reports Server (NTRS)

Melcher, John C., IV; Allred, Jennifer K.

2009-01-01

Tests were conducted with the RS18 rocket engine using liquid oxygen (LO2) and liquid methane (LCH4) propellants under simulated altitude conditions at NASA Johnson Space Center White Sands Test Facility (WSTF). This project is part of NASA s Propulsion and Cryogenics Advanced Development (PCAD) project. "Green" propellants, such as LO2/LCH4, offer savings in both performance and safety over equivalently sized hypergolic propellant systems in spacecraft applications such as ascent engines or service module engines. Altitude simulation was achieved using the WSTF Large Altitude Simulation System, which provided altitude conditions equivalent up to approx.120,000 ft (approx.37 km). For specific impulse calculations, engine thrust and propellant mass flow rates were measured. Propellant flow rate was measured using a coriolis-style mass-flow meter and compared with a serial turbine-style flow meter. Results showed a significant performance measurement difference during ignition startup. LO2 flow ranged from 5.9-9.5 lbm/sec (2.7-4.3 kg/sec), and LCH4 flow varied from 3.0-4.4 lbm/sec (1.4-2.0 kg/sec) during the RS-18 hot-fire test series. Thrust was measured using three load cells in parallel. Ignition was demonstrated using a gaseous oxygen/methane spark torch igniter. Data was obtained at multiple chamber pressures, and calculations were performed for specific impulse, C* combustion efficiency, and thrust vector alignment. Test objectives for the RS-18 project are 1) conduct a shakedown of the test stand for LO2/methane lunar ascent engines, 2) obtain vacuum ignition data for the torch and pyrotechnic igniters, and 3) obtain nozzle kinetics data to anchor two-dimensional kinetics codes.

Lawson concepts and criticality in DT fusion reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lartigue, J.G.

1987-12-01

The original Lawson concepts (amplification factor R and parameter n{tau}) as well as their applications in DT reactors are discussed in two cases: the ignition regime and the subignition regime in a self-sufficient plant. The modified Lawson factor or internal amplification factor R{sub a} (a function of alpha power) is proposed as a means to measure the ignition level reached by the plasma, in a more precise way than that given by the collective parameter (n{tau}kT). The self-sufficiency factor ({delta}) is proposed as a means to measure the plant self-sufficiency, {delta} being more significant than the traditional Q factor. Itmore » is stated that the ignition regime (R{sub a} = 1) is equivalent to a critical state (energy equilibrium); then, the corresponding critical mass concept is proposed. The analysis of the R{sub a} relationship with temperature (kT), (n{tau}), and recirculating factor ({var epsilon}) gives the conditions for the reactor to reach ignition or for the plant to reach self-sufficiency; it also shows that an approach to ignition is not improved by heating from 50 to 100 KeV.« less

Progress and prospects for an FI relevant point design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Key, M; Amendt, P; Bellei, C

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.

06-NIF Dedication: Steven Koonin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steven Koonin

2009-07-02

The National Ignition Facility, the world's largest laser system, was dedicated at a ceremony on May 29, 2009 at Lawrence Livermore National Laboratory. These are the remarks by Steven Koonin, the undersecretary for science of the U.S. Department of Energy.

07-NIF Dedication: Jerry McNerney

DOE Office of Scientific and Technical Information (OSTI.GOV)

Congressman Jerry McNerney

2009-07-02

The National Ignition Facility, the world's largest laser system, was dedicated at a ceremony on May 29, 2009 at Lawrence Livermore National Laboratory. These are the remarks by Congressman Jerry McNerney, of California's 11th district, which adjoins Livermore.

07-NIF Dedication: Jerry McNerney

ScienceCinema

Congressman Jerry McNerney

2017-12-09

The National Ignition Facility, the world's largest laser system, was dedicated at a ceremony on May 29, 2009 at Lawrence Livermore National Laboratory. These are the remarks by Congressman Jerry McNerney, of California's 11th district, which adjoins Livermore.

06-NIF Dedication: Steven Koonin

ScienceCinema

Steven Koonin

2017-12-09

The National Ignition Facility, the world's largest laser system, was dedicated at a ceremony on May 29, 2009 at Lawrence Livermore National Laboratory. These are the remarks by Steven Koonin, the undersecretary for science of the U.S. Department of Energy.

Theoretical Prediction of Microgravity Ignition Delay of Polymeric Fuels in Low Velocity Flows

NASA Technical Reports Server (NTRS)

Fernandez-Pello, A. C.; Torero, J. L.; Zhou, Y. Y.; Walther, D.; Ross, H. D.

2001-01-01

A new flammability apparatus and protocol, FIST (Forced Flow Ignition and Flame Spread Test), is under development. Based on the LIFT (Lateral Ignition and Flame Spread Test) protocol, FIST better reflects the environments expected in spacebased facilities. The final objective of the FIST research is to provide NASA with a test methodology that complements the existing protocol and provides a more comprehensive assessment of material flammability of practical materials for space applications. Theoretical modeling, an extensive normal gravity data bank and a few validation space experiments will support the testing methodology. The objective of the work presented here is to predict the ignition delay and critical heat flux for ignition of solid fuels in microgravity at airflow velocities below those induced in normal gravity. This is achieved through the application of a numerical model previously developed of piloted ignition of solid polymeric materials exposed to an external radiant heat flux. The model predictions will provide quantitative results about ignition of practical materials in the limiting conditions expected in space facilities. Experimental data of surface temperature histories and ignition delay obtained in the KC-135 aircraft are used to determine the critical pyrolysate mass flux for ignition and this value is subsequently used to predict the ignition delay and the critical heat flux for ignition of the material. Surface temperature and piloted ignition delay calculations for Polymethylmethacrylate (PMMA) and a Polypropylene/Fiberglass (PP/GL) composite were conducted under both reduced and normal gravity conditions. It was found that ignition delay times are significantly shorter at velocities below those induced by natural convection.

The national ignition facility high-energy ultraviolet laser system

NASA Astrophysics Data System (ADS)

Moses, Edward I.

2004-09-01

The National Ignition Facility (NIF), currently under construction at the Lawrence Livermore National Laboratory, is a stadium-sized facility containing a 192-beam, 1.8 MJ, 500 TW, ultraviolet laser system together with a 10-m diameter target chamber with room for nearly 100 experimental diagnostics. When completed, NIF will be the world's largest and most energetic laser experimental system, providing an international center to study inertial confinement fusion and the physics of matter at extreme energy densities and pressures. NIF's 192 energetic laser beams will compress fusion targets to conditions required for thermonuclear burn, liberating more energy than required to initiate the fusion reactions. Other NIF experiments will allow the study of physical processes at temperatures approaching 10 8 K and 10 11 Bar, conditions that exist naturally only in the interior of stars, planets and in nuclear weapons. NIF is now entering the first phases of its laser commissioning program. The first four beams of the NIF laser system have generated 106 kJ of infrared light and over 10 kJ at the third harmonic (351 nm). NIF's target experimental systems are also being installed in preparation for experiments to begin in late 2003. This paper provides a detailed look the NIF laser systems, the significant laser and optical systems breakthroughs that were developed, the results of recent laser commissioning shots, and plans for commissioning diagnostics for experiments on NIF.

The National Ignition Facility: an experimental platform for studying behavior of matter under extreme conditions

NASA Astrophysics Data System (ADS)

Moses, Edward

2011-11-01

The National Ignition Facility (NIF), a 192-beam Nd-glass laser facility capable of producing 1.8 MJ and 500 TW of ultraviolet light, is now operational at Lawrence Livermore National Laboratory (LLNL). As the world's largest and most energetic laser system, NIF serves as the national center for the U.S. Department of Energy (DOE) and National Nuclear Security Administration to achieve thermonuclear burn in the laboratory and to explore the behavior of matter at extreme temperatures and energy densities. By concentrating the energy from all of its 192 extremely energetic laser beams into a mm3-sized target, NIF can reach the conditions required to initiate fusion reactions. NIF can also provide access to extreme scientific environments: temperatures about 100 million K, densities of 1,000 g/cm3, and pressures 100 billion times atmospheric pressure. These conditions have never been created before in a laboratory and exist naturally only in interiors of the planetary and stellar environments as well as in nuclear weapons. Since August 2009, the NIF team has been conducting experiments in support of the National Ignition Campaign (NIC)—a partnership among LLNL, Los Alamos National Laboratory, General Atomics, the University of Rochester, Sandia National Laboratories, as well as a number of universities and international collaborators. The results from these initial experiments show promise for the relatively near-term achievement of ignition. Capsule implosion experiments at energies up to 1.2 MJ have demonstrated laser energetics, radiation temperatures, and symmetry control that scale to ignition conditions. Of particular importance is the demonstration of peak hohlraum temperatures near 300 eV with overall backscatter less than 10%. Cryogenic target capability and additional diagnostics are being installed in preparation for layered target deuterium-tritium implosions to be conducted later in 2010. Important national security and basic science experiments have also been conducted on NIF. This paper describes the unprecedented experimental capabilities of NIF and the results achieved so far on the path toward ignition, for stockpile stewardship, and the beginning of frontier science experiments. The paper will also address our plans to transition NIF to a national user facility, providing access to NIF for researchers from the DOE laboratories, as well as the national and international academic and fusion energy communities.

No Limit: Exploring the Science of the Universe

ScienceCinema

Meinecke, Jena; Remington, Bruce; Zylstra, Alex; Falcone, Roger; Rinderknecht, Hans; Casner, Alexis

2018-06-13

Scientists who conduct unique, cutting-edge Discovery Science experiments on Lawrence Livermore National Laboratory’s National Ignition Facility (NIF) describe the excitement of doing research on the world’s largest and highest-energy laser system.

A User's Guide for the Spacecraft Fire Safety Facility

NASA Technical Reports Server (NTRS)

Goldmeer, Jeffrey S.

2000-01-01

The Spacecraft Fire Safety Facility (SFSF) is a test facility that can be flown on NASA's reduced gravity aircraft to perform various types of combustion experiments under a variety of experimental conditions. To date, this facility has flown numerous times on the aircraft and has been used to perform experiments ranging from an examination of the effects transient depressurization on combustion, to ignition and flame spread. A list of pubfications/presentations based on experiments performed in the SFSF is included in the reference section. This facility consists of five main subsystems: combustion chamber, sample holders, gas flow system, imaging system, and the data acquisition/control system. Each of these subsystems will be reviewed in more detail. These subsystems provide the experiment operator with the ability to monitor and/or control numerous experimental parameters.

A polar-drive-ignition design for the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collins, T. J. B.; Marozas, J. A.; Anderson, K. S.

2012-05-15

Polar drive [Skupsky et al., Phys. Plasmas 11, 2763 (2004)] will enable direct-drive experiments to be conducted on the National Ignition Facility (NIF) [Miller et al., Opt. Eng. 43, 2841 (2004)], while the facility is configured for x-ray drive. A polar-drive ignition design for the NIF has been developed that achieves a gain of 32 in two-dimensional (2-D) simulations, which include single- and multiple-beam nonuniformities and ice and outer-surface roughness. This design requires both single-beam UV polarization smoothing and one-dimensional (1-D) multi-frequency modulator (MFM) single-beam smoothing to achieve the required laser uniformity. The multi-FM smoothing is employed only during themore » low-intensity portion of the laser pulse, allowing for the use of sufficient smoothing-by-spectral-dispersion bandwidth while maintaining safe laser operations during the high-intensity part of the pulse. This target is robust to all expected sources of perturbations.« less

Requirements and Capabilities for Fielding Cryogenic DT-Containing Fill-Tube Targets for Direct-Drive Experiments on OMEGA

DOE PAGES

Harding, D. R.; Ulreich, J.; Wittman, M. D.; ...

2017-12-06

Improving the performance of direct-drive cryogenic targets at the Omega Laser Facility requires the development of a new cryogenic system to (i) field non permeable targets with a fill tube, and (ii) provide a clean environment around the target. This capability is to demonstrate that imploding a scaled-down version of the direct-drive–ignition target for the National Ignition Facility (NIF) on the OMEGA laser will generate the hot-spot pressure that is needed for ignition; this will justify future cryogenic direct-drive experiments on the NIF. The paper describes the target, the cryogenic equipment that is being constructed to achieve this goal, andmore » the proposed target delivery process. Thermal calculations, fill-tube–based target designs, and structural/vibrational analyses are provided to demonstrate the credibility of the design. This new design will include capabilities not available (or possible) with the existing OMEGA cryogenic system, with the emphasis being to preserve a pristinely clean environment around the target, and to provide upgraded diagnostics to characterize both the ice layer and the target’s surface. The conceptual design is complete and testing of prototypes and subcomponents is underway. The rationale and capabilities of the new design are discussed.« less

Requirements and Capabilities for Fielding Cryogenic DT-Containing Fill-Tube Targets for Direct-Drive Experiments on OMEGA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harding, D. R.; Ulreich, J.; Wittman, M. D.

Improving the performance of direct-drive cryogenic targets at the Omega Laser Facility requires the development of a new cryogenic system to (i) field non permeable targets with a fill tube, and (ii) provide a clean environment around the target. This capability is to demonstrate that imploding a scaled-down version of the direct-drive–ignition target for the National Ignition Facility (NIF) on the OMEGA laser will generate the hot-spot pressure that is needed for ignition; this will justify future cryogenic direct-drive experiments on the NIF. The paper describes the target, the cryogenic equipment that is being constructed to achieve this goal, andmore » the proposed target delivery process. Thermal calculations, fill-tube–based target designs, and structural/vibrational analyses are provided to demonstrate the credibility of the design. This new design will include capabilities not available (or possible) with the existing OMEGA cryogenic system, with the emphasis being to preserve a pristinely clean environment around the target, and to provide upgraded diagnostics to characterize both the ice layer and the target’s surface. The conceptual design is complete and testing of prototypes and subcomponents is underway. The rationale and capabilities of the new design are discussed.« less

On the reactivity of methylbenzenes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silva, Gabriel da; Bozzelli, Joseph W.

2010-11-15

Alkylated aromatic hydrocarbons, including the methylbenzenes, are a major and growing component of liquid transportation fuels. Reactivity (or lack thereof) for the methylbenzenes in combustion systems, measured by octane rating, ignition delay, and laminar flame speed, varies widely with the number and position of methyl substituents. At present this behaviour is not fully understood. This study demonstrates how the low temperature and ignition reactivity of methylbenzenes is controlled by the presence of isolated methyl groups and adjacent methyl pairs (the ortho effect); this allows for the development of octane number correlations. Introduction of an isolated methyl group, adjacent only tomore » CH ring sites, consistently increases the research octane number (RON) by around 26. This phenomenon is explained by the formation of relatively unreactive benzyl free radicals. When an adjacent pair of methyl substituents is present the RON consistently decreases by between 8 and 26, compared to the case when these methyl groups are isolated from each other (this effect generally diminishes with increasing degree of substitution). Research octane numbers for all aromatics with zero to three methyl substituents are accurately described by the empirical relationship RON = 98 + 24.2n{sub m} - 25.8n{sub p}, where n{sub m} is the total number of methyl groups and n{sub p} is the number of contiguous adjacent methyl pairs. The ortho effect is attributed to the unique oxidation chemistry of o-methylbenzyl, o-methylbenzoxyl, and o-methylphenyl type radicals here we provide a preliminary exploration of this chemistry and highlight areas requiring further research. It is shown that the o-methylbenzyl radical can react with two oxygen molecules to form 1,2-diformylbenzene + 2OH + H, a highly chain-branching process. This chemistry is expected to largely explain the two-stage ignition and negative temperature coefficient (NTC) behavior witnessed for polymethylbenzenes with adjacent methyl pairs. Similar chain branching mechanisms exist in the oxidation of o-methylbenzoxyl radicals that also form during o-xylene ignition. (author)« less

The Mini Orange Spectrometer (MOS) for Stellar and Big-Bang Nucleosynthesis studies at OMEGA and the National Ignition Facility

NASA Astrophysics Data System (ADS)

Sutcliffe, G. D.; Frenje, J. A.; Gatu Johnson, M.; Li, C. K.; Parker, C.; Simpson, R.; Sio, H.; Seguin, F. H.; Petrasso, R. D.; Zylstra, A.

2017-10-01

A compact and highly efficient Mini Orange Spectrometer (MOS) is being designed for measurements of energy spectra of protons and alphas in the range of 1-12 MeV in experiments at the OMEGA laser facility and the National Ignition Facility (NIF). The MOS will extend charged-particle spectrometry at these laser facilities to lower energies (<5 MeV) and lower yields (<5×108) than current instrumentation allows. This new spectrometer will enable studies of low-probability stellar nucleosynthesis reactions, including the 3He+3He reaction that is part of the solar proton-proton chain. Its unique capabilities will also be exploited in other basic science experiments, including studies of stopping power in ICF-relevant plasmas, astrophysical shocks and kinetic physics. The MOS design achieves high efficiency by maximizing the solid angle of particle acceptance. The optimization of the MOS design uses simulated magnetic fields and particle tracing. Performance requirements of the MOS system, including desired detection efficiencies and energy resolution, are discussed. This work was supported in part by the U.S. DoE, LLNL, and LLE.

Direct Drive Fusion Energy Shock Ignition Designs for Sub-MJ Lasers

DTIC Science & Technology

2008-09-01

FUSION ENERGY SHOCK IGNITION DESIGNS FOR SUB-MJ LASERS Andrew J. Schmitt, J. W. Bates, S. P. Obenschain, and S. T. Zalesak Plasma Physics Division, Naval Research Laboratory, Washington DC 20375 andrew.schmitt@nrl.navy.mil D. E. Fyfe LCP&FD, Naval Research Laboratory, Washington DC 20375 R. Betti Fusion Science Center and Laboratory for Laser Energetics, University of Rochester, Rochester NY New approaches in target design have increased the pos- sibility that useful fusion power can be generated with sub-MJ lasers. We have performed many 1D and 2D

05-NIF Dedication: Tom D'Agostino

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tom D'Agostino,

2009-07-02

The National Ignition Facility, the world's largest laser system, was dedicated at a ceremony on May 29, 2009 at Lawrence Livermore National Laboratory. These are the remarks by Tom D'Agostino, the administrator of the U.S. Department of Energy's National Nuclear Security Administration.

X-ray driven implosions at ignition relevant velocities on the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meezan, N. B.; MacKinnon, A. J.; Hicks, D. G.

2013-05-15

Backlit convergent ablator experiments on the National Ignition Facility [E. I. Moses et al., Phys. Plasmas 16, 041006 (2009)] are indirect drive implosions that study the inflight dynamics of an imploding capsule. Side-on, backlit radiography provides data used by the National Ignition Campaign to measure time-dependent properties of the capsule ablator including its center of mass radius, velocity, and unablated mass. Previously, Callahan [D. A. Callahan et al., Phys. Plasmas 19, 056305 (2012)] and Hicks [D. H. Hicks et al., Phys. Plasmas 19, 122702 (2012)] reported backlit convergent ablator experiments demonstrating velocities approaching those required for ignition. This paper focusesmore » on implosion performance data in the “rocket curve” plane, velocity vs. ablator mass. These rocket curve data, along with supporting numerical simulations, show that the nominal 195 μm-thick ignition capsule would reach the ignition velocity goal V = 370 km/s with low ablator mass remaining–below the goal of M = 0.25 mg. This finding led to experiments with thicker capsule ablators. A recent symmetry capsule experiment with a 20 μm thicker capsule driven by 520 TW, 1.86 MJ laser pulse (along with a companion backlit convergent ablator experiment) appears to have demonstrated V≥350 km/s with ablator mass remaining above the ignition goal.« less

Method for detection of nuclear-plasma interactions in a 134Xe-doped exploding pusher at the National Ignition Facility

DOE PAGES

Bleuel, Daniel L.; Bernstein, Lee A.; Brand, Christopher A.; ...

2016-06-10

Angular momentum changes due to nuclear-plasma interactions on highly-excited nuclei in high energy density plasmas created at the National Ignition Facility can be measured through a change in isomer feeding following gamma emission. Here, we propose an experiment to detect these effects in 133Xe* in exploding pusher capsules.

Method for detection of nuclear-plasma interactions in a 134Xe-doped exploding pusher at the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bleuel, Daniel L.; Bernstein, Lee A.; Brand, Christopher A.

Angular momentum changes due to nuclear-plasma interactions on highly-excited nuclei in high energy density plasmas created at the National Ignition Facility can be measured through a change in isomer feeding following gamma emission. Here, we propose an experiment to detect these effects in 133Xe* in exploding pusher capsules.

Assessment and Mitigation of Electromagnetic Pulse (EMP) Impacts at Short-pulse Laser Facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Jr., C G; Bond, E; Clancy, T

2009-10-02

The National Ignition Facility (NIF) will be impacted by electromagnetic pulse (EMP) during normal long-pulse operation, but the largest impacts are expected during short-pulse operation utilizing the Advanced Radiographic Capability (ARC). Without mitigation these impacts could range from data corruption to hardware damage. We describe our EMP measurement systems on Titan and NIF and present some preliminary results and thoughts on mitigation.

Assessment and Mitigation of Electromagnetic Pulse (EMP) Impacts at Short-pulse Laser Facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Jr., C G; Bond, E; Clancy, T

2010-02-04

The National Ignition Facility (NIF) will be impacted by electromagnetic pulse (EMP) during normal long-pulse operation, but the largest impacts are expected during short-pulse operation utilizing the Advanced Radiographic Capability (ARC). Without mitigation these impacts could range from data corruption to hardware damage. We describe our EMP measurement systems on Titan and NIF and present some preliminary results and thoughts on mitigation.

Electrostatic hazards of charging of bedclothes and ignition in medical facilities.

PubMed

Endo, Yuta; Ohsawa, Atsushi; Yamaguma, Mizuki

2018-02-26

We investigated the charge generated on bedclothes (cotton and polyester) during bedding exchange with different humidities and the ignitability of an alcohol-based hand sanitizer (72.3 mass% ethanol) due to static spark with different temperatures to identify the hazards of electrostatic shocks and ignitions occurring previously in medical facilities. The results indicated that charging of the polyester bedclothes may induce a human body potential of over about 10 kV, resulting in shocks even at a relative humidity of 50%, and a human body potential of higher than about 8 kV can cause a risk for the ignition of the hand sanitizer. The grounding of human bodies via footwear and flooring, therefore, is essential to avoid such hazards (or to reduce such risks).

40 CFR 264.256 - Special requirements for ignitable or reactive waste.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., AND DISPOSAL FACILITIES Waste Piles § 264.256 Special requirements for ignitable or reactive waste. Ignitable or reactive waste must not be placed in a waste pile unless the waste and waste pile satisfy all... immediately after placement in the pile so that: (1) The resulting waste, mixture, or dissolution of material...

33 CFR 127.1605 - Other sources of ignition.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Other sources of ignition. 127... sources of ignition. Each operator of a waterfront facility handling LHG shall ensure that in the marine transfer area for LHG— (a) There are no open fires or open flame lamps; (b) Heating equipment will not...

360 Video Tour of the World’s Largest Laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

Welcome to the National Ignition Facility at Lawrence Livermore National Laboratory, the world’s largest and most energetic laser system. It draws researchers from around the globe for experiments that can’t be conducted anywhere else on Earth. Let’s take a closer look.

Validating hydrodynamic growth in National Ignition Facility implosions

DOE PAGES

Peterson, J. L.; Casey, D. T.; Hurricane, O. A.; ...

2015-05-12

We present new hydrodynamic growth experiments at the National Ignition Facility, which extend previous measurements up to Legendre mode 160 and convergence ratio 4, continuing the growth factor dispersion curve comparison of the low foot and high foot pulses reported by Casey et al. [Phys. Rev. E 90, 011102(R) (2014)]. We show that the high foot pulse has lower growth factor and lower growth rate than the low foot pulse. Using novel on-capsule fiducial markers, we observe that mode 160 inverts sign (changes phase) for the high foot pulse, evidence of amplitude oscillations during the Richtmyer-Meshkov phase of a sphericallymore » convergent system. Post-shot simulations are consistent with the experimental measurements for all but the shortest wavelength perturbations, reinforcing the validity of radiation hydrodynamic simulations of ablation front growth in inertial confinement fusion capsules.« less

Implementation of ISO 10110 optics drawing standards for the National Ignition Facility

NASA Astrophysics Data System (ADS)

Wang, David Y.; English, R. Edward, Jr.; Aikens, David M.

1999-11-01

The National Ignition Facility (NIF) project elected to implement ISO 10110 standard for the specifications of NIF optics drawings in 1996. More than 7,000 NIF large optics and 20,000 NIF small optics will be manufactured based on ISO 10110 indications. ISO 10110 standard meets many of the needs of the NIF optics specifications. It allows the optical engineer to quantify and clearly communicate the desired optical specifications. While no single drawing standard specifies all the requirements of high energy laser system, a combination of ISO 10110 standard with detailed notes make it possible to apply international drawing standards to the NIF laser system. This paper will briefly describe LLNL's interpretation and implementation of the ISO 10110 drawing standard, present some examples of NIF optics drawings, and discuss pros and cons of the indications from the perspective of this application. Emphasis will be given to the surface imperfection specifications, known as 5/, for the NIF optics.

Low-temperature Ignition-delay Characteristics of Several Rocket Fuels with Mixed Acid in Modified Open-cup-type Apparatus

NASA Technical Reports Server (NTRS)

Miller, Riley O

1950-01-01

Summaries of low-temperature self-ignition data of various rocket fuels with mixed acid (nitric plus sulfuric) are presented. Several fuels are shown to have shorter ignition-delay intervals and less variation in delay intervals at moderate and sub-zero temperatures than crude N-ethylaniline (monoethylaniline),a rocket fuel in current use.

Fuel Effects on Ignition and Their Impact on Advanced Combustion Engines (Poster)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, J.; Li, H.; Neill, S.

The objective of this report is to develop a pathway to use easily measured ignition properties as metrics for characterizing fuels in advanced combustion engine research--correlate IQT{trademark} measured parameters with engine data. In HCCL engines, ignition timing depends on the reaction rates throughout compression stroke: need to understand sensitivity to T, P, and [O{sub 2}]; need to rank fuels based on more than one set of conditions; and need to understand how fuel composition (molecular species) affect ignition properties.

Development of the Los Alamos National Laboratory Cryogenic Pressure Loader

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ebey, Peter S.; Dole, James M.; Hoffer, James K.

2003-05-15

Targets for inertial fusion research and ignition at OMEGA, the National Ignition Facility, LMJ, and future facilities rely on beta-radiation-driven layering of spherical cryogenic DT ice layers contained within plastic or metal shells. Plastic shells will be permeation filled at room temperature then cooled to cryogenic temperatures before removal of the overpressure. The cryogenic pressure loader (CPL) was recently developed at Los Alamos National Laboratory as a testbed for studying the filling and layering of plastic target shells with DT. A technical description of the CPL is provided. The CPL consists of a cryostat, which contains a high-pressure permeation cell,more » and has optical access for investigating beta layering. The cryostat is housed within a tritium glovebox that contains manifolds for supplying high-pressure DT. The CPL shares some design elements with the cryogenic target handling system at the OMEGA facility to allow testing of tritium issues related to that system. The CPL has the capability to fill plastic targets by permeation to pressures up to 100 MPa and to cool them to 15 K. The CPL will accommodate a range of targets and may be modified for future experiments.« less

High-Areal-Density Fuel Assembly in Direct-Drive Cryogenic Implosions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sangster, T. C.; Goncharov, V. N.; Radha, P. B.

The first observation of ignition-relevant areal-density deuterium from implosions of capsules with cryogenic fuel layers at ignition-relevant adiabats is reported. The experiments were performed on the 60-beam, 30-kJ{sub UV} OMEGA Laser System [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. Neutron-averaged areal densities of 202{+-}7 mg/cm{sup 2} and 182{+-}7 mg/cm{sup 2} (corresponding to estimated peak fuel densities in excess of 100 g/cm{sup 3}) were inferred using an 18-kJ direct-drive pulse designed to put the converging fuel on an adiabat of 2.5. These areal densities are in good agreement with the predictions of hydrodynamic simulations indicating that the fuelmore » adiabat can be accurately controlled under ignition-relevant conditions.« less

40 CFR 265.256 - Special requirements for ignitable or reactive waste.

Code of Federal Regulations, 2010 CFR

2010-07-01

... TREATMENT, STORAGE, AND DISPOSAL FACILITIES Waste Piles § 265.256 Special requirements for ignitable or reactive waste. (a) Ignitable or reactive waste must not be placed in a pile unless the waste and pile satisfy all applicable requirements of 40 CFR part 268, and: (1) Addition of the waste to an existing pile...

Shock Timing Plan for the National Ignition Campaign

NASA Astrophysics Data System (ADS)

Munro, D. H.; Robey, H. F.; Spears, B. K.; Boehly, T. R.

2006-10-01

We report progress on the design of the shock timing tuning procedure for the 2010 ignition campaign at the National Ignition Facility. Our keyhole target design provides adequate drive surrogacy for us to time the first three shocks empirically. The major risk to our plan is hard x-ray preheat, which can cause the diagnostic window to become opaque.

03-NIF Dedication: Norm Pattiz

DOE Office of Scientific and Technical Information (OSTI.GOV)

Norm Pattiz

2009-07-02

The National Ignition Facility, the world's largest laser system, was dedicated at a ceremony on May 29, 2009 at Lawrence Livermore National Laboratory. These are the remarks by Norm Pattiz, the chairman of Lawrence Livermore National Security, which manages Lawrence Livermore National Laboratory for the U.S. Department of Energy.

03-NIF Dedication: Norm Pattiz

ScienceCinema

Norm Pattiz

2017-12-09

The National Ignition Facility, the world's largest laser system, was dedicated at a ceremony on May 29, 2009 at Lawrence Livermore National Laboratory. These are the remarks by Norm Pattiz, the chairman of Lawrence Livermore National Security, which manages Lawrence Livermore National Laboratory for the U.S. Department of Energy.

An assessment of the use of antimisting fuel in turbofan engines

NASA Technical Reports Server (NTRS)

Fiorentino, A.; Desaro, R.; Franz, T.

1980-01-01

The effects of antimisting kerosene on the performance of the components from the fuel system and the combustor of a JT8D aircraft engine were evaluated. The problems associated with antimisting kerosene were identified and the extent of shearing or degradation required to allow the engine components to achieve satisfactory operation were determined. The performance of the combustor was assessed in a high pressure facility and in an altitude relight/cold ignition facility. The performance of the fuel pump and control system was evaluated in an open loop simulation.

A 1-D Study of the Ignition Space for Magnetic Indirect (X-ray) Drive Targets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cobble, James Allen; Sinars, Daniel Brian

The ICF program today is investigating three approaches to achieving multi-MJ fusion yields and ignition: (1) laser indirect (x-ray) drive on the National Ignition Facility (NIF), (2) laser direct drive (primarily on the Omega laser facility at the University of Rochester), and (3) magnetic direct drive on the Z pulsed power facility. In this white paper we briefly consider a fourth approach, magnetic indirect drive, in which pulsedpower- driven x-ray sources are used in place of laser driven sources. We first look at some of the x-ray sources studied on Z prior to 2007 before the pulsed power ICF programmore » shifted to magnetic direct drive. We then show results from a series of 1D Helios calculations of double-shell capsules that suggest that these sources, scaled to higher temperatures, could be a promising path to achieving multi-MJ fusion yields and ignition. We advocate here that more detailed design calculations with widely accepted 2D/3D ICF codes should be conducted for a better assessment of the prospects.« less

Progress towards ignition on the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, M. J.; Patel, P. K.; Lindl, J. D.

The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory includes a precision laser system now capable of delivering 1.8 MJ at 500 TW of 0.35-μm light to a target. NIF has been operational since March 2009. A variety of experiments have been completed in support of NIF's mission areas: national security, fundamental science, and inertial fusion energy. NIF capabilities and infrastructure are in place to support its missions with nearly 60 X-ray, optical, and nuclear diagnostic systems. A primary goal of the National Ignition Campaign (NIC) on the NIF was to implode a low-Z capsule filled with ∼0.2 mgmore » of deuterium-tritium (DT) fuel via laser indirect-drive inertial confinement fusion and demonstrate fusion ignition and propagating thermonuclear burn with a net energy gain of ∼5–10 (fusion yield/input laser energy). This requires assembling the DT fuel into a dense shell of ∼1000 g/cm{sup 3} with an areal density (ρR) of ∼1.5 g/cm{sup 2}, surrounding a lower density hot spot with a temperature of ∼10 keV and a ρR ∼0.3 g/cm{sup 2}, or approximately an α-particle range. Achieving these conditions demand precise control of laser and target parameters to allow a low adiabat, high convergence implosion with low ablator fuel mix. We have demonstrated implosion and compressed fuel conditions at ∼80–90% for most point design values independently, but not at the same time. The nuclear yield is a factor of ∼3–10× below the simulated values and a similar factor below the alpha dominated regime. This paper will discuss the experimental trends, the possible causes of the degraded performance (the off-set from the simulations), and the plan to understand and resolve the underlying physics issues.« less

Capsule implosion optimization during the indirect-drive National Ignition Campaign

NASA Astrophysics Data System (ADS)

Landen, O. L.; Edwards, J.; Haan, S. W.; Robey, H. F.; Milovich, J.; Spears, B. K.; Weber, S. V.; Clark, D. S.; Lindl, J. D.; MacGowan, B. J.; Moses, E. I.; Atherton, J.; Amendt, P. A.; Boehly, T. R.; Bradley, D. K.; Braun, D. G.; Callahan, D. A.; Celliers, P. M.; Collins, G. W.; Dewald, E. L.; Divol, L.; Frenje, J. A.; Glenzer, S. H.; Hamza, A.; Hammel, B. A.; Hicks, D. G.; Hoffman, N.; Izumi, N.; Jones, O. S.; Kilkenny, J. D.; Kirkwood, R. K.; Kline, J. L.; Kyrala, G. A.; Marinak, M. M.; Meezan, N.; Meyerhofer, D. D.; Michel, P.; Munro, D. H.; Olson, R. E.; Nikroo, A.; Regan, S. P.; Suter, L. J.; Thomas, C. A.; Wilson, D. C.

2011-05-01

Capsule performance optimization campaigns will be conducted at the National Ignition Facility [G. H. Miller, E. I. Moses, and C. R. Wuest, Nucl. Fusion 44, 228 (2004)] to substantially increase the probability of ignition. The campaigns will experimentally correct for residual uncertainties in the implosion and hohlraum physics used in our radiation-hydrodynamic computational models using a variety of ignition capsule surrogates before proceeding to cryogenic-layered implosions and ignition experiments. The quantitative goals and technique options and down selections for the tuning campaigns are first explained. The computationally derived sensitivities to key laser and target parameters are compared to simple analytic models to gain further insight into the physics of the tuning techniques. The results of the validation of the tuning techniques at the OMEGA facility [J. M. Soures et al., Phys. Plasmas 3, 2108 (1996)] under scaled hohlraum and capsule conditions relevant to the ignition design are shown to meet the required sensitivity and accuracy. A roll-up of all expected random and systematic uncertainties in setting the key ignition laser and target parameters due to residual measurement, calibration, cross-coupling, surrogacy, and scale-up errors has been derived that meets the required budget. Finally, we show how the tuning precision will be improved after a number of shots and iterations to meet an acceptable level of residual uncertainty.

Hohlraum-Driven Ignition-Like Double-Shell Implosion Experiments on Omega: Analysis and Interpretation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amendt, P; Robey, H F; Park, H-S

2003-08-22

An experimental campaign to study hohlraum-driven ignition-like double-shell target performance using the Omega laser facility has begun. These targets are intended to incorporate as many ignition-like properties of the proposed National Ignition Facility (NIF) double-shell ignition design [1,2] as possible, given the energy constraints of the Omega laser. In particular, this latest generation of Omega double-shells is nominally predicted to produce over 99% of the (clean) DD neutron yield from the compressional or stagnation phase of the implosion as required in the NIF ignition design. By contrast, previous double-shell experience on Omega [3] was restricted to cases where a significantmore » fraction of the observed neutron yield was produced during the earlier shock convergence phase where the effects of mix are deemed negligibly small. These new targets are specifically designed to have optimized fall-line behavior for mitigating the effects of pusher-fuel mix after deceleration onset and, thereby, providing maximum neutron yield from the stagnation phase. Experimental results from this recent Omega ignition-like double-shell implosion campaign show favorable agreement with two-dimensional integrated hohlraum simulation studies when enhanced (gold) hohlraum M-band (2-5 keV) radiation is included at a level consistent with observations.« less

The national ignition facility and atomic data

NASA Astrophysics Data System (ADS)

Crandall, David H.

1998-07-01

The National Ignition Facility (NIF) is under construction, capping over 25 years of development of the inertial confinement fusion concept by providing the facility to obtain fusion ignition in the laboratory for the first time. The NIF is a 192 beam glass laser to provide energy controlled in space and time so that a millimeter-scale capsule containing deuterium and tritium can be compressed to fusion conditions. Light transport, conversion of light in frequency, interaction of light with matter in solid and plasma forms, and diagnostics of extreme material conditions on small scale all use atomic data in preparing for use of the NIF. The NIF will provide opportunity to make measurements of atomic data in extreme physical environments related to fusion energy, nuclear weapon detonation, and astrophysics. The first laser beams of NIF should be operational in 2001 and the full facility completed at the end of 2003. NIF is to provide 1.8 megajoule of blue light on fusion targets and is intended to achieve fusion ignition by about the end of 2007. Today's inertial fusion development activities use atomic data to design and predict fusion capsule performance and in non-fusion applications to analyze radiation transport and radiation effects on matter. Conditions investigated involve radiation temperature of hundreds of eV, pressures up to gigabars and time scales of femptoseconds.

Ignition of metals in high pressure oxygen

NASA Technical Reports Server (NTRS)

Bransford, J. W.

1985-01-01

A description of an experimental facility used to determine the ignition and combustion characteristics of metallic materials is given. The results obtained for aluminum 6061, 302 stainless steel, and the nickel alloy - N06625 are presented.

Analysis of stimulated Raman backscatter and stimulated Brillouin backscatter in experiments performed on SG-III prototype facility with a spectral analysis code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hao, Liang; Zhao, Yiqing; Hu, Xiaoyan

2014-07-15

Experiments about the observations of stimulated Raman backscatter (SRS) and stimulated Brillouin backscatter (SBS) in Hohlraum were performed on Shenguang-III (SG-III) prototype facility for the first time in 2011. In this paper, relevant experimental results are analyzed for the first time with a one-dimension spectral analysis code, which is developed to study the coexistent process of SRS and SBS in Hohlraum plasma condition. Spectral features of the backscattered light are discussed with different plasma parameters. In the case of empty Hohlraum experiments, simulation results indicate that SBS, which grows fast at the energy deposition region near the Hohlraum wall, ismore » the dominant instability process. The time resolved spectra of SRS and SBS are numerically obtained, which agree with the experimental observations. For the gas-filled Hohlraum experiments, simulation results show that SBS grows fastest in Au plasma and amplifies convectively in C{sub 5}H{sub 12} gas, whereas SRS mainly grows in the high density region of the C{sub 5}H{sub 12} gas. Gain spectra and the spectra of backscattered light are simulated along the ray path, which clearly show the location where the intensity of scattered light with a certain wavelength increases. This work is helpful to comprehend the observed spectral features of SRS and SBS. The experiments and relevant analysis provide references for the ignition target design in future.« less

Hot-Spot Ignition Mechanisms for Explosives and Propellants

NASA Astrophysics Data System (ADS)

Field, J. E.; Bourne, N. K.; Palmer, S. J. P.; Walley, S. M.

1992-05-01

This paper describes the response of explosives to stress and impact and in particular the mechanisms of `hot-spot' production. Samples in the form of single crystals, powder layers, pressed pellets, gels, polymer bonded explosives (PBXs) and propellants have been studied. Techniques used include a drop-weight facility with transparent anvils which allows photography at microsecond framing intervals, an instrumented drop-weight machine, a miniaturized Hopkinson bar system for high strain rate property measurement, laser speckle for studying the deformation and fracture of PBXs, an automated system for analysing speckle patterns and heat sensitive film for recording the positions and temperatures of hot spots. Polishing and staining methods have been developed to observe the microstructure of PBXs and failure during quasi-static loading. Ignition, when it occurred, took place at local hot-spot sites. Evidence is discussed for a variety of ignition mechanisms including adiabatic shear of the explosive, adiabatic heating of trapped gases during cavity collapse, viscous flow, friction, fracture and shear of added particles and triboluminescent discharge.

Fuel Combustion Laboratory | Transportation Research | NREL

Science.gov Websites

detection of compounds at sub-parts per billion by volume levels. A high-performance liquid chromatograph ) platform; a high-pressure (1,200- bar) direct-injection system to minimize spray physics effects; and an combustion chamber. A high-speed pressure transducer measures chamber pressure to detect fuel ignition. Air

Proton pinhole imaging on the National Ignition Facility

NASA Astrophysics Data System (ADS)

Zylstra, A. B.; Park, H.-S.; Ross, J. S.; Fiuza, F.; Frenje, J. A.; Higginson, D. P.; Huntington, C.; Li, C. K.; Petrasso, R. D.; Pollock, B.; Remington, B.; Rinderknecht, H. G.; Ryutov, D.; Séguin, F. H.; Turnbull, D.; Wilks, S. C.

2016-11-01

Pinhole imaging of large (mm scale) carbon-deuterium (CD) plasmas by proton self-emission has been used for the first time to study the microphysics of shock formation, which is of astrophysical relevance. The 3 MeV deuterium-deuterium (DD) fusion proton self-emission from these plasmas is imaged using a novel pinhole imaging system, with up to five different 1 mm diameter pinholes positioned 25 cm from target-chamber center. CR39 is used as the detector medium, positioned at 100 cm distance from the pinhole for a magnification of 4 ×. A Wiener deconvolution algorithm is numerically demonstrated and used to interpret the images. When the spatial morphology is known, this algorithm accurately reproduces the size of features larger than about half the pinhole diameter. For these astrophysical plasma experiments on the National Ignition Facility, this provides a strong constraint on simulation modeling of the experiment.

Proton pinhole imaging on the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zylstra, Alex B.; Park, H. -S.; Ross, J. S.

Here, pinhole imaging of large (mm scale) carbon-deuterium (CD) plasmas by proton self-emission has been used for the first time to study the microphysics of shock formation, which is of astrophysical relevance. The 3 MeV deuterium-deuterium (DD) fusion proton self-emission from these plasmas is imaged using a novel pinhole imaging system, with up to five different 1 mm diameter pinholes positioned 25 cm from target-chamber center. CR39 is used as the detector medium, positioned at 100 cm distance from the pinhole for a magnification of 4×. A Wiener deconvolution algorithm is numerically demonstrated and used to interpret the images. Whenmore » the spatial morphology is known, this algorithm accurately reproduces the size of features larger than about half the pinhole diameter. For these astrophysical plasma experiments on the National Ignition Facility, this provides a strong constraint on simulation modeling of the experiment.« less

Proton pinhole imaging on the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zylstra, A. B., E-mail: zylstra@lanl.gov; Park, H.-S.; Ross, J. S.

Pinhole imaging of large (mm scale) carbon-deuterium (CD) plasmas by proton self-emission has been used for the first time to study the microphysics of shock formation, which is of astrophysical relevance. The 3 MeV deuterium-deuterium (DD) fusion proton self-emission from these plasmas is imaged using a novel pinhole imaging system, with up to five different 1 mm diameter pinholes positioned 25 cm from target-chamber center. CR39 is used as the detector medium, positioned at 100 cm distance from the pinhole for a magnification of 4 ×. A Wiener deconvolution algorithm is numerically demonstrated and used to interpret the images. Whenmore » the spatial morphology is known, this algorithm accurately reproduces the size of features larger than about half the pinhole diameter. For these astrophysical plasma experiments on the National Ignition Facility, this provides a strong constraint on simulation modeling of the experiment.« less

Proton pinhole imaging on the National Ignition Facility

DOE PAGES

Zylstra, Alex B.; Park, H. -S.; Ross, J. S.; ...

2016-07-29

Here, pinhole imaging of large (mm scale) carbon-deuterium (CD) plasmas by proton self-emission has been used for the first time to study the microphysics of shock formation, which is of astrophysical relevance. The 3 MeV deuterium-deuterium (DD) fusion proton self-emission from these plasmas is imaged using a novel pinhole imaging system, with up to five different 1 mm diameter pinholes positioned 25 cm from target-chamber center. CR39 is used as the detector medium, positioned at 100 cm distance from the pinhole for a magnification of 4×. A Wiener deconvolution algorithm is numerically demonstrated and used to interpret the images. Whenmore » the spatial morphology is known, this algorithm accurately reproduces the size of features larger than about half the pinhole diameter. For these astrophysical plasma experiments on the National Ignition Facility, this provides a strong constraint on simulation modeling of the experiment.« less

eHXI: A permanently installed, hard x-ray imager for the National Ignition Facility

DOE PAGES

Doppner, T.; Bachmann, B.; Albert, F.; ...

2016-06-14

We have designed and built a multi-pinhole imaging system for high energy x-rays (≥ 50 keV) that is permanently installed in the equatorial plane outside of the target chamber at the National Ignition Facility (NIF). It records absolutely-calibrated, time-integrated x-ray images with the same line-of-sight as the multi-channel, spatially integrating hard x-ray detector FFLEX [McDonald et al., Rev. Sci. Instrum. 75 (2004) 3753], having a side view of indirect-drive inertial confinement fusion (ICF) implosion targets. The equatorial hard x-ray imager (eHXI) has recorded images on the majority of ICF implosion experiments since May 2011. Lastly, eHXI provides valuable information onmore » hot electron distribution in hohlraum experiments, target alignment, potential hohlraum drive asymmetries and serves as a long term reference for the FFLEX diagnostics.« less

Proton pinhole imaging on the National Ignition Facility.

PubMed

Zylstra, A B; Park, H-S; Ross, J S; Fiuza, F; Frenje, J A; Higginson, D P; Huntington, C; Li, C K; Petrasso, R D; Pollock, B; Remington, B; Rinderknecht, H G; Ryutov, D; Séguin, F H; Turnbull, D; Wilks, S C

2016-11-01

Pinhole imaging of large (mm scale) carbon-deuterium (CD) plasmas by proton self-emission has been used for the first time to study the microphysics of shock formation, which is of astrophysical relevance. The 3 MeV deuterium-deuterium (DD) fusion proton self-emission from these plasmas is imaged using a novel pinhole imaging system, with up to five different 1 mm diameter pinholes positioned 25 cm from target-chamber center. CR39 is used as the detector medium, positioned at 100 cm distance from the pinhole for a magnification of 4 ×. A Wiener deconvolution algorithm is numerically demonstrated and used to interpret the images. When the spatial morphology is known, this algorithm accurately reproduces the size of features larger than about half the pinhole diameter. For these astrophysical plasma experiments on the National Ignition Facility, this provides a strong constraint on simulation modeling of the experiment.

High-energy (>70 keV) x-ray conversion efficiency measurement on the ARC laser at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Chen, Hui; Hermann, M. R.; Kalantar, D. H.; Martinez, D. A.; Di Nicola, P.; Tommasini, R.; Landen, O. L.; Alessi, D.; Bowers, M.; Browning, D.; Brunton, G.; Budge, T.; Crane, J.; Di Nicola, J.-M.; Döppner, T.; Dixit, S.; Erbert, G.; Fishler, B.; Halpin, J.; Hamamoto, M.; Heebner, J.; Hernandez, V. J.; Hohenberger, M.; Homoelle, D.; Honig, J.; Hsing, W.; Izumi, N.; Khan, S.; LaFortune, K.; Lawson, J.; Nagel, S. R.; Negres, R. A.; Novikova, L.; Orth, C.; Pelz, L.; Prantil, M.; Rushford, M.; Shaw, M.; Sherlock, M.; Sigurdsson, R.; Wegner, P.; Widmayer, C.; Williams, G. J.; Williams, W.; Whitman, P.; Yang, S.

2017-03-01

The Advanced Radiographic Capability (ARC) laser system at the National Ignition Facility (NIF) is designed to ultimately provide eight beamlets with a pulse duration adjustable from 1 to 30 ps, and energies up to 1.5 kJ per beamlet. Currently, four beamlets have been commissioned. In the first set of 6 commissioning target experiments, the individual beamlets were fired onto gold foil targets with energy up to 1 kJ per beamlet at 20-30 ps pulse length. The x-ray energy distribution and pulse duration were measured, yielding energy conversion efficiencies of 4-9 × 10-4 for x-rays with energies greater than 70 keV. With greater than 3 J of such x-rays, ARC provides a high-precision x-ray backlighting capability for upcoming inertial confinement fusion and high-energy-density physics experiments on NIF.

Oxygen-hydrogen thrusters for Space Station auxiliary propulsion systems

NASA Technical Reports Server (NTRS)

Berkman, D. K.

1984-01-01

The feasibility and technology requirements of a low-thrust, high-performance, long-life, gaseous oxygen (GO2)/gaseous hydrogen (GH2) thruster were examined. Candidate engine concepts for auxiliary propulsion systems for space station applications were identified. The low-thrust engine (5 to 100 lb sub f) requires significant departure from current applications of oxygen/hydrogen propulsion technology. Selection of the thrust chamber material and cooling method needed or long life poses a major challenge. The use of a chamber material requiring a minimum amount of cooling or the incorporation of regenerative cooling were the only choices available with the potential of achieving very high performance. The design selection for the injector/igniter, the design and fabrication of a regeneratively cooled copper chamber, and the design of a high-temperature rhenium chamber were documented and the performance and heat transfer results obtained from the test program conducted at JPL using the above engine components presented. Approximately 115 engine firings were conducted in the JPL vacuum test facility, using 100:1 expansion ratio nozzles. Engine mixture ratio and fuel-film cooling percentages were parametrically investigated for each test configuration.

Assessing the prospects for achieving double-shell ignition on the National Ignition Facility using vacuum hohlraums

NASA Astrophysics Data System (ADS)

Amendt, Peter

2006-10-01

The goal of demonstrating ignition on the National Ignition Facility (NIF) has motivated a revisit of double-shell (DS) [1] targets as a complementary path to the baseline cryogenic single-shell approach [2]. Benefits of DS targets include room-temperature deuterium-tritium (DT) fuel preparation, minimal hohlraum-plasma-mediated laser backscatter, low threshold-ignition temperatures (4 keV) for relaxed hohlraum x-ray flux asymmetry tolerances [3], and loose shock timing requirements. On the other hand, DS ignition presents several challenges, including room-temperature containment of high-pressure DT (790 atm) in the inner shell; strict concentricity requirements on the two shells; development of nanoporous, low-density, metallic foams for structural support of the inner shell and hydrodynamic instability mitigation; and effective control of perturbation growth on the high-Atwood number interface between the DT fuel and the high-Z inner shell. Recent progress in DS ignition target designs using vacuum hohlraums is described, offering the potential for low levels of laser backscatter from stimulated Raman and Brillouin processes. In addition, vacuum hohlraums have the operational advantages of room temperature fielding and fabrication simplicity, as well as benefiting from extensive benchmarking on the Nova and Omega laser facilities. As an alternative to standard cylindrical hohlraums, a rugby-shaped geometry is also introduced that may provide energetics and symmetry tuning benefits for more robust DS designs with yields exceeding 10 MJ for 2 MJ of 3w laser energy. The recent progress in hohlraum designs and required advanced materials development are scheduled to culminate in a prototype demonstration of a NIF-scale ignition-ready DS in 2007. [1] P. Amendt et al., PoP 9, 2221 (2002). [2] J.D. Lindl et al., PoP 11, 339 (2004). [3] M.N. Chizhkov et al., Laser Part. Beams 23, 261 (2005). In collaboration with C. Cerjan, A. Hamza, J. Milovich and H. Robey.

Transport Simulations for Fast Ignition on NIF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strozzi, D J; Tabak, M; Grote, D P

2009-10-26

We are designing a full hydro-scale cone-guided, indirect-drive FI coupling experiment, for NIF, with the ARC-FIDO short-pulse laser. Current rad-hydro designs with limited fuel jetting into cone tip are not yet adequate for ignition. Designs are improving. Electron beam transport simulations (implicit-PIC LSP) show: (1) Magnetic fields and smaller angular spreads increase coupling to ignition-relevant 'hot spot' (20 um radius); (2) Plastic CD (for a warm target) produces somewhat better coupling than pure D (cryogenic target) due to enhanced resistive B fields; and (3) The optimal T{sub hot} for this target is {approx} 1 MeV; coupling falls by 3x asmore » T{sub hot} rises to 4 MeV.« less

Diagnosing and controlling mix in National Ignition Facility implosion experiments a)

NASA Astrophysics Data System (ADS)

Hammel, B. A.; Scott, H. A.; Regan, S. P.; Cerjan, C.; Clark, D. S.; Edwards, M. J.; Epstein, R.; Glenzer, S. H.; Haan, S. W.; Izumi, N.; Koch, J. A.; Kyrala, G. A.; Landen, O. L.; Langer, S. H.; Peterson, K.; Smalyuk, V. A.; Suter, L. J.; Wilson, D. C.

2011-05-01

High mode number instability growth of "isolated defects" on the surfaces of National Ignition Facility [Moses et al., Phys. Plasmas 16, 041006 (2009)] capsules can be large enough for the perturbation to penetrate the imploding shell, and produce a jet of ablator material that enters the hot-spot. Since internal regions of the CH ablator are doped with Ge, mixing of this material into the hot-spot results in a clear signature of Ge K-shell emission. Evidence of jets entering the hot-spot has been recorded in x-ray images and spectra, consistent with simulation predictions [Hammel et al., High Energy Density Phys. 6, 171 (2010)]. Ignition targets have been designed to minimize instability growth, and capsule fabrication improvements are underway to reduce "isolated defects." An experimental strategy has been developed where the final requirements for ignition targets can be adjusted through direct measurements of mix and experimental tuning.

Performance of High-Convergence, Layered DT Implosions on Power-Scaling Experiments at National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smalyuk, V. A.; Atherton, L. J.; Benedetti, L. R.

The radiation-driven, low-adiabat, cryogenic DT layered plastic capsule implosions were carried out on the National Ignition Facility (NIF) to study the sensitivity of performance to peak power and drive duration. An implosion with extended drive and at reduced peak power of 350 TW achieved the highest compression with fuel areal density of ~1.3±0.1 g/cm 2, representing a significant step from previously measured ~1.0 g/cm 2 toward a goal of 1.5 g/cm 2. Moreover, for future experiments will focus on understanding and mitigating hydrodynamic instabilities and mix, and improving symmetry required to reach the threshold for thermonuclear ignition on NIF.

Performance of High-Convergence, Layered DT Implosions on Power-Scaling Experiments at National Ignition Facility

DOE PAGES

Smalyuk, V. A.; Atherton, L. J.; Benedetti, L. R.; ...

2013-10-19

The radiation-driven, low-adiabat, cryogenic DT layered plastic capsule implosions were carried out on the National Ignition Facility (NIF) to study the sensitivity of performance to peak power and drive duration. An implosion with extended drive and at reduced peak power of 350 TW achieved the highest compression with fuel areal density of ~1.3±0.1 g/cm 2, representing a significant step from previously measured ~1.0 g/cm 2 toward a goal of 1.5 g/cm 2. Moreover, for future experiments will focus on understanding and mitigating hydrodynamic instabilities and mix, and improving symmetry required to reach the threshold for thermonuclear ignition on NIF.

Progress Toward Ignition on the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kauffman, R L

2011-10-17

The principal approach to ignition on the National Ignition Facility (NIF) is indirect drive. A schematic of an ignition target is shown in Figure 1. The laser beams are focused through laser entrance holes at each end of a high-Z cylindrical case, or hohlraum. The lasers irradiate the hohlraum walls producing x-rays that ablate and compress the fuel capsule in the center of the hohlraum. The hohlraum is made of Au, U, or other high-Z material. For ignition targets, the hohlraum is {approx}0.5 cm diameter by {approx}1 cm in length. The hohlraum absorbs the incident laser energy producing x-rays formore » symmetrically imploding the capsule. The fuel capsule is a {approx}2-mm-diameter spherical shell of CH, Be, or C filled with DT fuel. The DT fuel is in the form of a cryogenic layer on the inside of the capsule. X-rays ablate the outside of the capsule, producing a spherical implosion. The imploding shell stagnates in the center, igniting the DT fuel. NIC has overseen installation of all of the hardware for performing ignition experiments, including commissioning of approximately 50 diagnostic systems in NIF. The diagnostics measure scattered optical light, x-rays from the hohlraum over the energy range from 100 eV to 500 keV, and x-rays, neutrons, and charged particles from the implosion. An example of a diagnostic is the Magnetic Recoil Spectrometer (MRS) built by a collaboration of scientists from MIT, UR-LLE, and LLNL shown in Figure 2. MRS measures the neutron spectrum from the implosion, providing information on the neutron yield and areal density that are metrics of the quality of the implosion. Experiments on NIF extend ICF research to unexplored regimes in target physics. NIF can produce more than 50 times the laser energy and more than 20 times the power of any previous ICF facility. Ignition scale hohlraum targets are three to four times larger than targets used at smaller facilities, and the ignition drive pulses are two to five times longer. The larger targets and longer pulse lengths produce unique plasma conditions for laser-plasma instabilities that could reduce hohlraum coupling efficiency. Initial experiments have demonstrated efficient coupling of laser energy to x-rays. X-ray drive greater than 300 eV has been measured in gas-filled ignition hohlraum and shows the expected scaling with laser energy and hohlraum scale size. Experiments are now optimizing capsule implosions for ignition. Ignition conditions require assembling the fuel with sufficient density and temperature for thermonuclear burn. X-rays ablate the outside of the capsule, accelerating and spherically compressing the capsule for assembling the fuel. The implosion stagnates, heating the central core and producing a hot spot that ignites and burns the surrounding fuel. The four main characteristics of the implosion are shell velocity, central hot spot shape, fuel adiabat, and mix. Experiments studying these four characteristics of implosions are used to optimize the implosion. Integrated experiments using cryogenic fuel layer experiments demonstrate the quality of the implosion as the optimization experiments progress. The final compressed fuel conditions are diagnosed by measuring the x-ray emission from the hot core and the neutrons and charged particles produced in the fusion reactions. Metrics of the quality of the implosion are the neutron yield and the shell areal density, as well as the size and shape of the core. The yield depends on the amount of fuel in the hot core and its temperature and is a gauge of the energy coupling to the fuel. The areal density, the density of the fuel times its thickness, diagnoses the fuel assembly, which is measured using the fraction of neutrons that are down scattered passing through the dense shell. The yield and fraction of down scattered neutrons, or shell rho-r, from the cryogenic layered implosions are shown in Figure 3. The different sets of data represent results after a series of implosion optimization experiments. Both yield and areal density show significant increases as a result of the optimization. The experimental Ignition Threshold Factor (ITFX) is a measure of the progress toward ignition. ITFX is analogous to the Lawson Criterion in Magnetic Fusion. Implosions have improved by over a factor of 50 since the first cryogenic layered experiments were done in September 2010. This increase is a measure of the progress made toward the ignition goal in the past year. Optimization experiments are planned in the coming year for continued improvement in implosion performance to achieve the ignition goal. In summary, NIF has made significant progress toward ignition in the 30 months since project completion. Diagnostics and all of the supporting equipment are in place for ignition experiments. The Ignition Campaign is under way as a national collaborative effort of all the National Nuclear Security Administration (NNSA) science laboratories as well as international partners.« less

Design of the opacity spectrometer for opacity measurements at the National Ignition Facility

DOE PAGES

Ross, P. W.; Heeter, R. F.; Ahmed, M. F.; ...

2016-10-03

Recent experiments at the Sandia National Laboratory Z facility have called into question models used in calculating opacity, of importance for modeling stellar interiors. An effort is being made to reproduce these results at the National Ignition Facility (NIF). These experiments require a new X-ray opacity spectrometer (OpSpec) spanning 540 eV–2100 eV with a resolving power E/ΔE > 700. The design of the OpSpec is presented. Photometric calculations based on expected opacity data are also presented in this paper. First use on NIF is expected in September 2016.

Design of the opacity spectrometer for opacity measurements at the National Ignition Facility.

PubMed

Ross, P W; Heeter, R F; Ahmed, M F; Dodd, E; Huffman, E J; Liedahl, D A; King, J A; Opachich, Y P; Schneider, M B; Perry, T S

2016-11-01

Recent experiments at the Sandia National Laboratory Z facility have called into question models used in calculating opacity, of importance for modeling stellar interiors. An effort is being made to reproduce these results at the National Ignition Facility (NIF). These experiments require a new X-ray opacity spectrometer (OpSpec) spanning 540 eV-2100 eV with a resolving power E/ΔE > 700. The design of the OpSpec is presented. Photometric calculations based on expected opacity data are also presented. First use on NIF is expected in September 2016.

The design of the optical Thomson scattering diagnostic for the National Ignition Facility.

PubMed

Datte, P S; Ross, J S; Froula, D H; Daub, K D; Galbraith, J; Glenzer, S; Hatch, B; Katz, J; Kilkenny, J; Landen, O; Manha, D; Manuel, A M; Molander, W; Montgomery, D; Moody, J; Swadling, G F; Weaver, J

2016-11-01

The National Ignition Facility (NIF) is a 192 laser beam facility designed to support the Stockpile Stewardship, High Energy Density and Inertial Confinement Fusion (ICF) programs. We report on the design of an Optical Thomson Scattering (OTS) diagnostic that has the potential to transform the community's understanding of NIF hohlraum physics by providing first principle, local, time-resolved measurements of under-dense plasma conditions. The system design allows operation with different probe laser wavelengths by manual selection of the appropriate beam splitter and gratings before the shot. A deep-UV probe beam (λ 0 -210 nm) will be used to optimize the scattered signal for plasma densities of 5 × 10 20 electrons/cm 3 while a 3ω probe will be used for experiments investigating lower density plasmas of 1 × 10 19 electrons/cm 3 . We report the phase I design of a two phase design strategy. Phase I includes the OTS telescope, spectrometer, and streak camera; these will be used to assess the background levels at NIF. Phase II will include the design and installation of a probe laser.

Capsule implosion optimization during the indirect-drive National Ignition Campaign

DOE Office of Scientific and Technical Information (OSTI.GOV)

Landen, O. L.; Edwards, J.; Haan, S. W.

2011-05-15

Capsule performance optimization campaigns will be conducted at the National Ignition Facility [G. H. Miller, E. I. Moses, and C. R. Wuest, Nucl. Fusion 44, 228 (2004)] to substantially increase the probability of ignition. The campaigns will experimentally correct for residual uncertainties in the implosion and hohlraum physics used in our radiation-hydrodynamic computational models using a variety of ignition capsule surrogates before proceeding to cryogenic-layered implosions and ignition experiments. The quantitative goals and technique options and down selections for the tuning campaigns are first explained. The computationally derived sensitivities to key laser and target parameters are compared to simple analyticmore » models to gain further insight into the physics of the tuning techniques. The results of the validation of the tuning techniques at the OMEGA facility [J. M. Soures et al., Phys. Plasmas 3, 2108 (1996)] under scaled hohlraum and capsule conditions relevant to the ignition design are shown to meet the required sensitivity and accuracy. A roll-up of all expected random and systematic uncertainties in setting the key ignition laser and target parameters due to residual measurement, calibration, cross-coupling, surrogacy, and scale-up errors has been derived that meets the required budget. Finally, we show how the tuning precision will be improved after a number of shots and iterations to meet an acceptable level of residual uncertainty.« less

Determination of the relative resistance to ignition of selected turbopump materials in high-pressure, high-temperature, oxygen environments, volume 1

NASA Technical Reports Server (NTRS)

Stoltzfus, Joel M.; Benz, Frank J.

1986-01-01

Advances in the design of the liquid oxygen, liquid hydrogen engines for the Space Transportation System call for the use of warm, high-pressure oxygen as the driving gas in the liquid oxygen turbopump. The NASA Lewis Research Center requested the NASA White Sands Test Facility (WSTF) to design a test program to determine the relative resistance to ignition of nine selected turbopump materials: Hastelloy X, Inconel 600, Invar 36, Monel K-500, nickel 200, silicon carbide, stainless steel 316, and zirconium copper. The materials were subjected to particle impact and to frictional heating in high-pressure oxygen.

THE ANALYSIS OF URANIUM-ZIRCONIUM ALLOYS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milner, G.W.C.; Skewies, A.F.

1953-03-01

A satisfactory procedure is described for the analysis of uranium-zirconium alloys containing up to 25% zirconium. It is based on the separation of the zirconium from the uranium by dissolving the cupferron complex of the former element into chloroform. After the evaporation of the solvent from the combined organic extracts, the residue is ignited to zirconium oxide. The latter is then re-dissolved and zirconium is separated from other elements co-extracted in the solvent extraction procedure by precipitation with mandelic acid. The zirconium mandelate is finally ignited to oxide at 960 deg C. The uranium is separated from the aqueous solutionmore » remaining from the cupferron extraction by precipitating with tannin at a pH of 8; the precipitate being removed by filtration and then ignited a t 800 deg C. The residue is dissolved in nitric acid and the uranium is finally determined by precipitating as ammonium diuranate and then igniting to U{sub 3}O{sub 8}. (auth)« less

Wavefront control of high-power laser beams in the National Ignition Facility (NIF)

NASA Astrophysics Data System (ADS)

Zacharias, Richard A.; Bliss, Erlan S.; Winters, Scott; Sacks, Richard A.; Feldman, Mark; Grey, Andrew; Koch, Jeffrey A.; Stolz, Christopher J.; Toeppen, John S.; Van Atta, Lewis; Woods, Bruce W.

2000-04-01

The use of lasers as the driver for inertial confinement fusion and weapons physics experiments is based on their ability to produce high-energy short pulses in a beam with low divergence. Indeed, the focusability of high quality laser beams far exceeds alternate technologies and is a major factor in the rationale for building high power lasers for such applications. The National Ignition Facility (NIF) is a large, 192-beam, high-power laser facility under construction at the Lawrence Livermore National Laboratory for fusion and weapons physics experiments. Its uncorrected minimum focal spot size is limited by laser system aberrations. The NIF includes a Wavefront Control System to correct these aberrations to yield a focal spot small enough for its applications. Sources of aberrations to be corrected include prompt pump-induced distortions in the laser amplifiers, previous-shot thermal distortions, beam off-axis effects, and gravity, mounting, and coating-induced optic distortions. Aberrations from gas density variations and optic-manufacturing figure errors are also partially corrected. This paper provides an overview of the NIF Wavefront Control System and describes the target spot size performance improvement it affords. It describes provisions made to accommodate the NIF's high fluence (laser beam and flashlamp), large wavefront correction range, wavefront temporal bandwidth, temperature and humidity variations, cleanliness requirements, and exception handling requirements (e.g. wavefront out-of-limits conditions).

Generalized Lawson Criteria for Inertial Confinement Fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tipton, Robert E.

2015-08-27

The Lawson Criterion was proposed by John D. Lawson in 1955 as a general measure of the conditions necessary for a magnetic fusion device to reach thermonuclear ignition. Over the years, similar ignition criteria have been proposed which would be suitable for Inertial Confinement Fusion (ICF) designs. This paper will compare and contrast several ICF ignition criteria based on Lawson’s original ideas. Both analytical and numerical results will be presented which will demonstrate that although the various criteria differ in some details, they are closely related and perform similarly as ignition criteria. A simple approximation will also be presented whichmore » allows the inference of each ignition parameter directly from the measured data taken on most shots fired at the National Ignition Facility (NIF) with a minimum reliance on computer simulations. Evidence will be presented which indicates that the experimentally inferred ignition parameters on the best NIF shots are very close to the ignition threshold.« less

NIF featured on BBC "Horizon"

ScienceCinema

Brian Cox

2017-12-09

The National Ignition Facility, the world's largest laser system, located at Lawrence Livermore National Laboratory, was featured in the BBC broadcast "Horizon" hosted by physicist Brian Cox. Here is the NIF portion of the program, which was entitled "Can We Make A Star On Earth?" This video is used with the express permission of the BBC.

NIF featured on BBC "Horizon"

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brian Cox

2010-01-12

The National Ignition Facility, the world's largest laser system, located at Lawrence Livermore National Laboratory, was featured in the BBC broadcast "Horizon" hosted by physicist Brian Cox. Here is the NIF portion of the program, which was entitled "Can We Make A Star On Earth?" This video is used with the express permission of the BBC.

Ignition Temperatures of Metals in Oxygen Atmospheres

NASA Technical Reports Server (NTRS)

Laurendeau, N. M.; Glassman, I.

1971-01-01

The ignition temperature of ten common non-toxic metals has been determined experimentally in an oxygen environment. In this investigation a induction furnace facility that emphasized the preignition surface.oxidation effects upon the ignition temperature was used. The bulk ignition temperatures of barium, bismuth, calcium, iron, lead, magnesium, molybdenum, strontium, tin, and zinc were found and compared to the previous results of Grosse and Conway. The differences in the results are attributed to how the heating cycle is carried out and how the cycle affects the surface oxide coat.

Nitrogen enriched combustion of a natural gas internal combustion engine to reduce NO.sub.x emissions

DOEpatents

Biruduganti, Munidhar S.; Gupta, Sreenath Borra; Sekar, R. Raj; McConnell, Steven S.

2008-11-25

A method and system for reducing nitrous oxide emissions from an internal combustion engine. An input gas stream of natural gas includes a nitrogen gas enrichment which reduces nitrous oxide emissions. In addition ignition timing for gas combustion is advanced to improve FCE while maintaining lower nitrous oxide emissions.

The Nova Upgrade Facility for ICF ignition and gain

NASA Astrophysics Data System (ADS)

Lowdermilk, W. H.; Campbell, E. M.; Hunt, J. T.; Murray, J. R.; Storm, E.; Tobin, M. T.; Trenholme, J. B.

1992-01-01

Research on Inertial Confinement Fusion (ICF) is motivated by its potential defense and civilian applications, including ultimately the generation of electric power. The U.S. ICF Program was reviewed recently by the National Academy of Science (NAS) and the Fusion Policy Advisory Committee (FPAC). Both committees issued final reports in 1991 which recommended that first priority in the ICF program be placed on demonstrating fusion ignition and modest gain (G less than 10). The U.S. Department of Energy and Lawrence Livermore National Laboratory (LLNL) have proposed an upgrade of the existing Nova Laser Facility at LLNL to accomplish these goals. Both the NAS and FPAC have endorsed the upgrade of Nova as the optimal path to achieving ignition and gain. Results from Nova Upgrade Experiments will be used to define requirements for driver and target technology both for future high-yield military applications, such as the Laboratory Microfusion Facility (LMF) proposed by the Department of Energy, and for high-gain energy applications leading to an ICF engineering test facility. The central role and modifications which Nova Upgrade would play in the national ICF strategy are described.

Science & Technology Review June 2012

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poyneer, L A

2012-04-20

This month's issue has the following articles: (1) A New Era in Climate System Analysis - Commentary by William H. Goldstein; (2) Seeking Clues to Climate Change - By comparing past climate records with results from computer simulations, Livermore scientists can better understand why Earth's climate has changed and how it might change in the future; (3) Finding and Fixing a Supercomputer's Faults - Livermore experts have developed innovative methods to detect hardware faults in supercomputers and help applications recover from errors that do occur; (4) Targeting Ignition - Enhancements to the cryogenic targets for National Ignition Facility experiments aremore » furthering work to achieve fusion ignition with energy gain; (5) Neural Implants Come of Age - A new generation of fully implantable, biocompatible neural prosthetics offers hope to patients with neurological impairment; and (6) Incubator Busy Growing Energy Technologies - Six collaborations with industrial partners are using the Laboratory's high-performance computing resources to find solutions to urgent energy-related problems.« less

Demonstration of Fuel Hot-Spot Pressure in Excess of 50 Gbar for Direct-Drive, Layered Deuterium-Tritium Implosions on OMEGA

NASA Astrophysics Data System (ADS)

Regan, S. P.; Goncharov, V. N.; Igumenshchev, I. V.; Sangster, T. C.; Betti, R.; Bose, A.; Boehly, T. R.; Bonino, M. J.; Campbell, E. M.; Cao, D.; Collins, T. J. B.; Craxton, R. S.; Davis, A. K.; Delettrez, J. A.; Edgell, D. H.; Epstein, R.; Forrest, C. J.; Frenje, J. A.; Froula, D. H.; Gatu Johnson, M.; Glebov, V. Yu.; Harding, D. R.; Hohenberger, M.; Hu, S. X.; Jacobs-Perkins, D.; Janezic, R.; Karasik, M.; Keck, R. L.; Kelly, J. H.; Kessler, T. J.; Knauer, J. P.; Kosc, T. Z.; Loucks, S. J.; Marozas, J. A.; Marshall, F. J.; McCrory, R. L.; McKenty, P. W.; Meyerhofer, D. D.; Michel, D. T.; Myatt, J. F.; Obenschain, S. P.; Petrasso, R. D.; Radha, P. B.; Rice, B.; Rosenberg, M. J.; Schmitt, A. J.; Schmitt, M. J.; Seka, W.; Shmayda, W. T.; Shoup, M. J.; Shvydky, A.; Skupsky, S.; Solodov, A. A.; Stoeckl, C.; Theobald, W.; Ulreich, J.; Wittman, M. D.; Woo, K. M.; Yaakobi, B.; Zuegel, J. D.

2016-07-01

A record fuel hot-spot pressure Phs=56 ±7 Gbar was inferred from x-ray and nuclear diagnostics for direct-drive inertial confinement fusion cryogenic, layered deuterium-tritium implosions on the 60-beam, 30-kJ, 351-nm OMEGA Laser System. When hydrodynamically scaled to the energy of the National Ignition Facility, these implosions achieved a Lawson parameter ˜60 % of the value required for ignition [A. Bose et al., Phys. Rev. E 93, LM15119ER (2016)], similar to indirect-drive implosions [R. Betti et al., Phys. Rev. Lett. 114, 255003 (2015)], and nearly half of the direct-drive ignition-threshold pressure. Relative to symmetric, one-dimensional simulations, the inferred hot-spot pressure is approximately 40% lower. Three-dimensional simulations suggest that low-mode distortion of the hot spot seeded by laser-drive nonuniformity and target-positioning error reduces target performance.

Demonstration of fuel hot-spot pressure in excess of 50 Gbar for direct-drive, layered deuterium-tritium implosions on OMEGA

DOE PAGES

Regan, S. P.; Goncharov, V. N.; Igumenshchev, I. V.; ...

2016-07-07

A record fuel hot-spot pressure P hs = 56±7 Gbar was inferred from x-ray and nuclear diagnostics for direct-drive inertial confinement fusion cryogenic, layered deuterium–tritium implosions on the 60-beam, 30-kJ, 351-nm OMEGA Laser System. When hydrodynamically scaled to the energy of the National Ignition Facility (NIF), these implosions achieved a Lawson parameter ~60% of the value required for ignition [A. Bose et al., Phys. Rev. E (in press)], similar to indirect-drive implosions [R. Betti et al., Phys. Rev. Lett. 114, 255003 (2015)], and nearly half of the direct-drive ignition-threshold pressure. Relative to symmetric, one-dimensional simulations, the inferred hot-spot pressure ismore » ~40% lower. Furthermore, three-dimensional simulations suggest that low-mode distortion of the hot spot seeded by laser-drive nonuniformity and target-positioning error reduces target performance.« less

Demonstration of fuel hot-spot pressure in excess of 50 Gbar for direct-drive, layered deuterium-tritium implosions on OMEGA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Regan, S. P.; Goncharov, V. N.; Igumenshchev, I. V.

A record fuel hot-spot pressure P hs = 56±7 Gbar was inferred from x-ray and nuclear diagnostics for direct-drive inertial confinement fusion cryogenic, layered deuterium–tritium implosions on the 60-beam, 30-kJ, 351-nm OMEGA Laser System. When hydrodynamically scaled to the energy of the National Ignition Facility (NIF), these implosions achieved a Lawson parameter ~60% of the value required for ignition [A. Bose et al., Phys. Rev. E (in press)], similar to indirect-drive implosions [R. Betti et al., Phys. Rev. Lett. 114, 255003 (2015)], and nearly half of the direct-drive ignition-threshold pressure. Relative to symmetric, one-dimensional simulations, the inferred hot-spot pressure ismore » ~40% lower. Furthermore, three-dimensional simulations suggest that low-mode distortion of the hot spot seeded by laser-drive nonuniformity and target-positioning error reduces target performance.« less

Radiation effects on active camera electronics in the target chamber at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Dayton, M.; Datte, P.; Carpenter, A.; Eckart, M.; Manuel, A.; Khater, H.; Hargrove, D.; Bell, P.

2017-08-01

The National Ignition Facility's (NIF) harsh radiation environment can cause electronics to malfunction during high-yield DT shots. Until now there has been little experience fielding electronic-based cameras in the target chamber under these conditions; hence, the performance of electronic components in NIF's radiation environment was unknown. It is possible to purchase radiation tolerant devices, however, they are usually qualified for radiation environments different to NIF, such as space flight or nuclear reactors. This paper presents the results from a series of online experiments that used two different prototype camera systems built from non-radiation hardened components and one commercially available camera that permanently failed at relatively low total integrated dose. The custom design built in Livermore endured a 5 × 1015 neutron shot without upset, while the other custom design upset at 2 × 1014 neutrons. These results agreed with offline testing done with a flash x-ray source and a 14 MeV neutron source, which suggested a methodology for developing and qualifying electronic systems for NIF. Further work will likely lead to the use of embedded electronic systems in the target chamber during high-yield shots.

Validating Inertial Confinement Fusion (ICF) predictive capability using perturbed capsules

NASA Astrophysics Data System (ADS)

Schmitt, Mark; Magelssen, Glenn; Tregillis, Ian; Hsu, Scott; Bradley, Paul; Dodd, Evan; Cobble, James; Flippo, Kirk; Offerman, Dustin; Obrey, Kimberly; Wang, Yi-Ming; Watt, Robert; Wilke, Mark; Wysocki, Frederick; Batha, Steven

2009-11-01

Achieving ignition on NIF is a monumental step on the path toward utilizing fusion as a controlled energy source. Obtaining robust ignition requires accurate ICF models to predict the degradation of ignition caused by heterogeneities in capsule construction and irradiation. LANL has embarked on a project to induce controlled defects in capsules to validate our ability to predict their effects on fusion burn. These efforts include the validation of feature-driven hydrodynamics and mix in a convergent geometry. This capability is needed to determine the performance of capsules imploded under less-than-optimum conditions on future IFE facilities. LANL's recently initiated Defect Implosion Experiments (DIME) conducted at Rochester's Omega facility are providing input for these efforts. Recent simulation and experimental results will be shown.

Thin Shell, High Velocity Inertial Confinement Fusion Implosions on the National Ignition Facility

NASA Astrophysics Data System (ADS)

Ma, T.; Hurricane, O. A.; Callahan, D. A.; Barrios, M. A.; Casey, D. T.; Dewald, E. L.; Dittrich, T. R.; Döppner, T.; Haan, S. W.; Hinkel, D. E.; Berzak Hopkins, L. F.; Le Pape, S.; MacPhee, A. G.; Pak, A.; Park, H.-S.; Patel, P. K.; Remington, B. A.; Robey, H. F.; Salmonson, J. D.; Springer, P. T.; Tommasini, R.; Benedetti, L. R.; Bionta, R.; Bond, E.; Bradley, D. K.; Caggiano, J.; Celliers, P.; Cerjan, C. J.; Church, J. A.; Dixit, S.; Dylla-Spears, R.; Edgell, D.; Edwards, M. J.; Field, J.; Fittinghoff, D. N.; Frenje, J. A.; Gatu Johnson, M.; Grim, G.; Guler, N.; Hatarik, R.; Herrmann, H. W.; Hsing, W. W.; Izumi, N.; Jones, O. S.; Khan, S. F.; Kilkenny, J. D.; Knauer, J.; Kohut, T.; Kozioziemski, B.; Kritcher, A.; Kyrala, G.; Landen, O. L.; MacGowan, B. J.; Mackinnon, A. J.; Meezan, N. B.; Merrill, F. E.; Moody, J. D.; Nagel, S. R.; Nikroo, A.; Parham, T.; Ralph, J. E.; Rosen, M. D.; Rygg, J. R.; Sater, J.; Sayre, D.; Schneider, M. B.; Shaughnessy, D.; Spears, B. K.; Town, R. P. J.; Volegov, P. L.; Wan, A.; Widmann, K.; Wilde, C. H.; Yeamans, C.

2015-04-01

Experiments have recently been conducted at the National Ignition Facility utilizing inertial confinement fusion capsule ablators that are 175 and 165 μ m in thickness, 10% and 15% thinner, respectively, than the nominal thickness capsule used throughout the high foot and most of the National Ignition Campaign. These three-shock, high-adiabat, high-foot implosions have demonstrated good performance, with higher velocity and better symmetry control at lower laser powers and energies than their nominal thickness ablator counterparts. Little to no hydrodynamic mix into the DT hot spot has been observed despite the higher velocities and reduced depth for possible instability feedthrough. Early results have shown good repeatability, with up to 1 /2 the neutron yield coming from α -particle self-heating.

Scalable Sub-micron Patterning of Organic Materials Toward High Density Soft Electronics.

PubMed

Kim, Jaekyun; Kim, Myung-Gil; Kim, Jaehyun; Jo, Sangho; Kang, Jingu; Jo, Jeong-Wan; Lee, Woobin; Hwang, Chahwan; Moon, Juhyuk; Yang, Lin; Kim, Yun-Hi; Noh, Yong-Young; Jaung, Jae Yun; Kim, Yong-Hoon; Park, Sung Kyu

2015-09-28

The success of silicon based high density integrated circuits ignited explosive expansion of microelectronics. Although the inorganic semiconductors have shown superior carrier mobilities for conventional high speed switching devices, the emergence of unconventional applications, such as flexible electronics, highly sensitive photosensors, large area sensor array, and tailored optoelectronics, brought intensive research on next generation electronic materials. The rationally designed multifunctional soft electronic materials, organic and carbon-based semiconductors, are demonstrated with low-cost solution process, exceptional mechanical stability, and on-demand optoelectronic properties. Unfortunately, the industrial implementation of the soft electronic materials has been hindered due to lack of scalable fine-patterning methods. In this report, we demonstrated facile general route for high throughput sub-micron patterning of soft materials, using spatially selective deep-ultraviolet irradiation. For organic and carbon-based materials, the highly energetic photons (e.g. deep-ultraviolet rays) enable direct photo-conversion from conducting/semiconducting to insulating state through molecular dissociation and disordering with spatial resolution down to a sub-μm-scale. The successful demonstration of organic semiconductor circuitry promise our result proliferate industrial adoption of soft materials for next generation electronics.

Scalable Sub-micron Patterning of Organic Materials Toward High Density Soft Electronics

NASA Astrophysics Data System (ADS)

Kim, Jaekyun; Kim, Myung-Gil; Kim, Jaehyun; Jo, Sangho; Kang, Jingu; Jo, Jeong-Wan; Lee, Woobin; Hwang, Chahwan; Moon, Juhyuk; Yang, Lin; Kim, Yun-Hi; Noh, Yong-Young; Yun Jaung, Jae; Kim, Yong-Hoon; Kyu Park, Sung

2015-09-01

The success of silicon based high density integrated circuits ignited explosive expansion of microelectronics. Although the inorganic semiconductors have shown superior carrier mobilities for conventional high speed switching devices, the emergence of unconventional applications, such as flexible electronics, highly sensitive photosensors, large area sensor array, and tailored optoelectronics, brought intensive research on next generation electronic materials. The rationally designed multifunctional soft electronic materials, organic and carbon-based semiconductors, are demonstrated with low-cost solution process, exceptional mechanical stability, and on-demand optoelectronic properties. Unfortunately, the industrial implementation of the soft electronic materials has been hindered due to lack of scalable fine-patterning methods. In this report, we demonstrated facile general route for high throughput sub-micron patterning of soft materials, using spatially selective deep-ultraviolet irradiation. For organic and carbon-based materials, the highly energetic photons (e.g. deep-ultraviolet rays) enable direct photo-conversion from conducting/semiconducting to insulating state through molecular dissociation and disordering with spatial resolution down to a sub-μm-scale. The successful demonstration of organic semiconductor circuitry promise our result proliferate industrial adoption of soft materials for next generation electronics.

Heavy-Duty Stoichiometric Compression Ignition Engine with Improved Fuel Economy over Alternative Technologies for Meeting 2010 On-Highway Emission

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kirby J. Baumgard; Richard E. Winsor

2009-12-31

The objectives of the reported work were: to apply the stoichiometric compression ignition (SCI) concept to a 9.0 liter diesel engine; to obtain engine-out NO{sub x} and PM exhaust emissions so that the engine can meet 2010 on-highway emission standards by applying a three-way catalyst for NO{sub x} control and a particulate filter for PM control; and to simulate an optimize the engine and air system to approach 50% thermal efficiency using variable valve actuation and electric turbo compounding. The work demonstrated that an advanced diesel engine can be operated at stoichiometric conditions with reasonable particulate and NOx emissions atmore » full power and peak torque conditions; calculated that the SCI engine will operate at 42% brake thermal efficiency without advanced hardware, turbocompounding, or waste heat recovery; and determined that EGR is not necessary for this advanced concept engine, and this greatly simplifies the concept.« less

Collision of plane thermonuclear detonation waves in a preliminarily compressed DT mixture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khishchenko, K. V., E-mail: konst@ihed.ras.ru; Charakhch’yan, A. A., E-mail: chara@ccas.ru

2015-03-15

The paper deals with a one-dimensional problem on symmetric irradiation of a plane DT fuel layer with a thickness 2H and density ρ{sub 0} ⩽ 100ρ{sub s} (where ρ{sub s} is the density of the DT fuel in the solid state at atmospheric pressure and a temperature of 4 K) by two identical monoenergetic proton beams with a kinetic energy of 1 MeV, an intensity of 10{sup 19} W/cm{sup 2}, and a duration of 50 ps. The problem is solved in the framework of one-fluid two-temperature hydrodynamic model that takes into account the equation of state for hydrogen, electron andmore » ion heat conductivities, kinetics of the DT reaction, plasma self-radiation, and plasma heating by α-particles. The irradiation of the fuel results in the appearance of two counterpropagating detonation waves to the fronts of which rarefaction waves are adjacent. The efficiency of the DT reaction after the collision (reflection from the plane of symmetry) of the detonation waves depends on the spatial homogeneity of thermodynamic functions between the fronts of the reflected detonation waves. At Hρ{sub 0} ≈ 1 g/cm{sup 2}, the gain factor is G ≈ 200, whereas at Hρ{sub 0} ≈ 5 g/cm{sup 2}, it is G > 2000. As applied to a cylindrical target that is ignited from ends and in which the cylinder with the fuel is surrounded by a heavy magnetized shell, the obtained values of the burn-up and gain factors are maximum possible. To estimate the ignition energy E{sub ig} of a cylindrical target by using solutions to the one-dimensional problem, a quasi-one-dimensional model is developed. The model assumes that the main mechanism of target ignition is fuel heating by α-particles. The trajectories of α-particles are limited by a cylindrical surface with a given radius, which is a parameter of the model and is identified with the fuel radius in the target and the radii of the irradiating proton beams. This model reproduces the well-known theoretical dependence E{sub ig} ∼ ρ{sub 0}{sup −2} and yields E{sub ig} = 160 kJ as a lower estimate of the ignition energy for ρ{sub 0} = 100ρ{sub s} ≈ 22 g/cm{sup 3}.« less

Rocket Launch-Induced Vibration and Ignition Overpressure Response

NASA Technical Reports Server (NTRS)

Caimi, Raoul; Margasahayam, Ravi; Nayfeh, Jamal; Thompson, Karen (Technical Monitor)

2001-01-01

Rocket-induced vibration and ignition overpressure response environments are predicted in the low-frequency (5 to 200 hertz) range. The predictions are necessary to evaluate their impact on critical components, structures, and facilities in the immediate vicinity of the rocket launch pad.

Recent advances and results from the solid radiochemistry nuclear diagnostic at the National Ignition Facility

DOE PAGES

Gharibyan, N.; Shaughnessy, D. A.; Moody, K. J.; ...

2016-08-05

The solid debris collection capability at the National Ignition Facility has been expanded to include a third line-of-sight assembly. The solid radiochemistry nuclear diagnostic measurement of the ratio of gold isotopes is dependent on the efficient collection of neutron-activated hohlraum debris by passive metal disks. As a result, the collection of target debris at this new location is more reliable in comparison to the historic locations, and it appears to be independent of collector surface ablation.

Recent advances and results from the solid radiochemistry nuclear diagnostic at the National Ignition Facility.

PubMed

Gharibyan, N; Shaughnessy, D A; Moody, K J; Grant, P M; Despotopulos, J D; Faye, S A; Jedlovec, D R; Yeamans, C B

2016-11-01

The solid debris collection capability at the National Ignition Facility has been expanded to include a third line-of-sight assembly. The solid radiochemistry nuclear diagnostic measurement of the ratio of gold isotopes is dependent on the efficient collection of neutron-activated hohlraum debris by passive metal disks. The collection of target debris at this new location is more reliable in comparison to the historic locations, and it appears to be independent of collector surface ablation.

Assessment and Mitigation of Diagnostic-Generated Electromagnetic Interference at the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, C G; Ayers, M J; Felker, B

2012-04-20

Electromagnetic interference (EMI) is an ever-present challenge at laser facilities such as the National Ignition Facility (NIF). The major source of EMI at such facilities is laser-target interaction that can generate intense electromagnetic fields within, and outside of, the laser target chamber. In addition, the diagnostics themselves can be a source of EMI, even interfering with themselves. In this paper we describe EMI generated by ARIANE and DIXI, present measurements, and discuss effects of the diagnostic-generated EMI on ARIANE's CCD and on a PMT nearby DIXI. Finally we present some of the efforts we have made to mitigate the effectsmore » of diagnostic-generated EMI on NIF diagnostics.« less

ICF quarterly report January - March 1997 volume 7, number 3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murray, J

The National Ignition Facility Project The mission of the National Ignition Facility (NIF) is to produce ignition and modest energy gain in inertial confinement fusion (ICF) targets. Achieving these goals will maintain U.S. world leadership in ICF and will directly benefit the U.S. Department of Energy (DOE) missions in national security, science and technology, energy resources, and industrial competitiveness. Development and operation of the NIF are consistent with DOE goals for environmental quality, openness to the community, and nuclear nonproliferation and arms control. Although the primary mission of inertial fusion is for defense applications, inertial fusion research will provide criticalmore » information for the development of inertial fusion energy. The NIF, under construction at Lawrence Livermore National Laboratory (LLNL), is a cornerstone of the DOE's science-based Stockpile Stewardship Program for addressing high-energy-density physics issues in the absence of nuclear weapons testing. In pursuit of this mission, the DOE's Defense Programs has developed a state-of-the-art capability with the NIF to investigate high-energy-density physics in the laboratory with a microfusion capability for defense and energy applications. As a Strategic System Acquisition, the NIF Project has a separate and disciplined reporting chain to DOE as shown below.« less

Scaling laws for ignition at the National Ignition Facility from first principles.

PubMed

Cheng, Baolian; Kwan, Thomas J T; Wang, Yi-Ming; Batha, Steven H

2013-10-01

We have developed an analytical physics model from fundamental physics principles and used the reduced one-dimensional model to derive a thermonuclear ignition criterion and implosion energy scaling laws applicable to inertial confinement fusion capsules. The scaling laws relate the fuel pressure and the minimum implosion energy required for ignition to the peak implosion velocity and the equation of state of the pusher and the hot fuel. When a specific low-entropy adiabat path is used for the cold fuel, our scaling laws recover the ignition threshold factor dependence on the implosion velocity, but when a high-entropy adiabat path is chosen, the model agrees with recent measurements.

Liquid Oxygen/Liquid Methane Test Results of the RS-18 Lunar Ascent Engine at Simulated Altitude Conditions at NASA White Sands Test Facility

NASA Technical Reports Server (NTRS)

Melcher, John C., IV; Allred, Jennifer K.

2009-01-01

Tests were conducted with the RS-18 rocket engine using liquid oxygen (LO2) and liquid methane (LCH4) propellants under simulated altitude conditions at NASA Johnson Space Center White Sands Test Facility (WSTF). This project is part of NASA's Propulsion and Cryogenics Advanced Development (PCAD) project. "Green" propellants, such as LO2/LCH4, offer savings in both performance and safety over equivalently sized hypergolic propulsion systems in spacecraft applications such as ascent engines or service module engines. Altitude simulation was achieved using the WSTF Large Altitude Simulation System, which provided altitude conditions equivalent up to 122,000 ft (37 km). For specific impulse calculations, engine thrust and propellant mass flow rates were measured. LO2 flow ranged from 5.9 - 9.5 lbm/sec (2.7 - 4.3 kg/sec), and LCH4 flow varied from 3.0 - 4.4 lbm/sec (1.4 - 2.0 kg/sec) during the RS-18 hot-fire test series. Propellant flow rate was measured using a coriolis mass-flow meter and compared with a serial turbine-style flow meter. Results showed a significant performance measurement difference during ignition startup due to two-phase flow effects. Subsequent cold-flow testing demonstrated that the propellant manifolds must be adequately flushed in order for the coriolis flow meters to give accurate data. The coriolis flow meters were later shown to provide accurate steady-state data, but the turbine flow meter data should be used in transient phases of operation. Thrust was measured using three load cells in parallel, which also provides the capability to calculate thrust vector alignment. Ignition was demonstrated using a gaseous oxygen/methane spark torch igniter. Test objectives for the RS-18 project are 1) conduct a shakedown of the test stand for LO2/methane lunar ascent engines, 2) obtain vacuum ignition data for the torch and pyrotechnic igniters, and 3) obtain nozzle kinetics data to anchor two-dimensional kinetics codes. All of these objectives were met with the RS-18 data and additional testing data from subsequent LO2/methane test programs in 2009 which included the first simulated-altitude pyrotechnic ignition demonstration of LO2/methane.

Catalytic Microtube Rocket Igniter

NASA Technical Reports Server (NTRS)

Schneider, Steven J.; Deans, Matthew C.

2011-01-01

Devices that generate both high energy and high temperature are required to ignite reliably the propellant mixtures in combustion chambers like those present in rockets and other combustion systems. This catalytic microtube rocket igniter generates these conditions with a small, catalysis-based torch. While traditional spark plug systems can require anywhere from 50 W to multiple kW of power in different applications, this system has demonstrated ignition at less than 25 W. Reactants are fed to the igniter from the same tanks that feed the reactants to the rest of the rocket or combustion system. While this specific igniter was originally designed for liquid methane and liquid oxygen rockets, it can be easily operated with gaseous propellants or modified for hydrogen use in commercial combustion devices. For the present cryogenic propellant rocket case, the main propellant tanks liquid oxygen and liquid methane, respectively are regulated and split into different systems for the individual stages of the rocket and igniter. As the catalyst requires a gas phase for reaction, either the stored boil-off of the tanks can be used directly or one stream each of fuel and oxidizer can go through a heat exchanger/vaporizer that turns the liquid propellants into a gaseous form. For commercial applications, where the reactants are stored as gases, the system is simplified. The resulting gas-phase streams of fuel and oxidizer are then further divided for the individual components of the igniter. One stream each of the fuel and oxidizer is introduced to a mixing bottle/apparatus where they are mixed to a fuel-rich composition with an O/F mass-based mixture ratio of under 1.0. This premixed flow then feeds into the catalytic microtube device. The total flow is on the order of 0.01 g/s. The microtube device is composed of a pair of sub-millimeter diameter platinum tubes connected only at the outlet so that the two outlet flows are parallel to each other. The tubes are each approximately 10 cm long and are heated via direct electric resistive heating. This heating brings the gasses to their minimum required ignition temperature, which is lower than the auto-thermal ignition temperature, and causes the onset of both surface and gas phase ignition producing hot temperatures and a highly reacting flame. The combustion products from the catalytic tubes, which are below the melting point of platinum, are injected into the center of another combustion stage, called the primary augmenter. The reactants for this combustion stage come from the same source but the flows of non-premixed methane and oxygen gas are split off to a secondary mixing apparatus and can be mixed in a near-stoichiometric to highly lean mixture ratio. The primary augmenter is a component that has channels venting this mixed gas to impinge on each other in the center of the augmenter, perpendicular to the flow from the catalyst. The total crosssectional area of these channels is on a similar order as that of the catalyst. The augmenter has internal channels that act as a manifold to distribute equally the gas to the inward-venting channels. This stage creates a stable flame kernel as its flows, which are on the order of 0.01 g/s, are ignited by the combustion products of the catalyst. This stage is designed to produce combustion products in the flame kernel that exceed the autothermal ignition temperature of oxygen and methane.

40 CFR 264.229 - Special requirements for ignitable or reactive waste.

Code of Federal Regulations, 2010 CFR

2010-07-01

... reactive waste. 264.229 Section 264.229 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Surface Impoundments § 264.229 Special requirements for ignitable or reactive...

40 CFR 264.281 - Special requirements for ignitable or reactive waste.

Code of Federal Regulations, 2014 CFR

2014-07-01

... reactive waste. 264.281 Section 264.281 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Land Treatment § 264.281 Special requirements for ignitable or reactive waste...

40 CFR 264.281 - Special requirements for ignitable or reactive waste.

Code of Federal Regulations, 2012 CFR

2012-07-01

... reactive waste. 264.281 Section 264.281 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Land Treatment § 264.281 Special requirements for ignitable or reactive waste...

40 CFR 264.281 - Special requirements for ignitable or reactive waste.

Code of Federal Regulations, 2011 CFR

2011-07-01

... reactive waste. 264.281 Section 264.281 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Land Treatment § 264.281 Special requirements for ignitable or reactive waste...

40 CFR 264.281 - Special requirements for ignitable or reactive waste.

Code of Federal Regulations, 2013 CFR

2013-07-01

... reactive waste. 264.281 Section 264.281 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Land Treatment § 264.281 Special requirements for ignitable or reactive waste...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bozkurt, Y.; Misirlioglu, Z.; Sinag, A.

The reactivities of chars obtained by pyrolysis of Bursa Mustafa Kemal Pasa Alpagut lignite and Balkesir Dursunbey Cakiirca lignite (Turkey) at different temperatures were determined by CO{sub 2} gasification and by combustion with O{sub 2}. Catalytic effect of Na{sub 2}CO{sub 3} on the CO{sub 2} and O{sub 2} gasification reactivity of chars was investigated. Gasification tests were performed in the fixed bed reactors operating at ambient pressure. Reactivity of chars during the CO{sub 2} gasification reactions was determined by calculating the reaction rate constants and reactivity of chars during the O{sub 2} gasification was determined by using ignition temperatures ofmore » the samples. Activation energies and Arrhenius constants of the chars on the CO{sub 2} gasification reactions were also calculated by the help of Arrhenius curves. The activation energy for CO{sub 2} gasification was generally decreased with pyrolysis temperature, due to the different surface characteristics and different nature of carbon atoms gasified as the gasification reactions proceed. Generally, the increase in pyrolysis temperature leads to an increase in gasification reactivity with CO{sub 2}. The reactivity of chars in catalytic gasification was higher than the corresponding non-catalytic reactivity of the same chars. Ignition temperature increased with increasing pyrolysis temperature.« less

X-ray diffraction diagnostic design for the National Ignition Facility

NASA Astrophysics Data System (ADS)

Ahmed, Maryum F.; House, Allen; Smith, R. F.; Ayers, Jay; Lamb, Zachary S.; Swift, David W.

2013-09-01

This paper describes the design considerations for Target Diffraction In-Situ (TARDIS), an x-ray diffraction diagnostic at the National Ignition Facility. A crystal sample is ramp-compressed to peak pressures between 10 and 30 Mbar and, during a pressure hold period, is probed with quasi-monochromatic x-rays emanating from a backlighter source foil. The crystal spectrography diffraction lines are recorded onto image plates. The crystal sample, filter, and image plates are packaged into one assembly, allowing for accurate and repeatable target to image plate registration. Unconverted laser light impinges upon the device, generating debris, the effects of which have been mitigated. Dimpled blast shields, high strength steel alloy, and high-z tungsten are used to shield and protect the image plates. A tapered opening was designed to provide adequate thickness of shielding materials without blocking the drive beams or x-ray source from reaching the crystal target. The high strength steel unit serves as a mount for the crystal target and x-ray source foil. A tungsten body contains the imaging components. Inside this sub-assembly, there are three image plates: a 160 degree field of view curved plate directly opposite the target opening and two flat plates for the top and bottom. A polycarbonate frame, coated with the appropriate filter material and embedded with registration features for image plate location, is inserted into the diagnostic body. The target assembly is metrologized and then the diagnostic assembly is attached.

Laser-Plasma Interaction Experiments at Direct-Drive Ignition-Relevant Plasma Conditions at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Solodov, A. A.; Rosenberg, M. J.; Myatt, J. F.; Shaw, J. G.; Seka, W.; Epstein, R.; Short, R. W.; Follett, R. K.; Regan, S. P.; Froula, D. H.; Radha, P. B.; Michel, P.; Chapman, T.; Hohenberger, M.

2017-10-01

Laser-plasma interaction (LPI) instabilities, such as stimulated Raman scattering (SRS) and two-plasmon decay, can be detrimental for direct-drive inertial confinement fusion because of target preheat by the high-energy electrons they generate. The radiation-hydrodynamic code DRACO was used to design planar-target experiments at the National Ignition Facility that generated plasma and interaction conditions relevant to ignition direct-drive designs (IL 1015W/cm2 , Te > 3 keV, density gradient scale lengths of Ln 600 μm). Laser-energy conversion efficiency to hot electrons of 0.5% to 2.5% with temperature of 45 to 60 keV was inferred from the experiment when the laser intensity at the quarter-critical surface increased from 6 to 15 ×1014W/cm2 . LPI was dominated by SRS, as indicated by the measured scattered-light spectra. Simulations of SRS using the LPI code LPSE have been performed and compared with predictions of theoretical models. Implications for ignition-scale direct-drive experiments will be discussed. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

360 Video Tour of the World’s Largest Laser

ScienceCinema

None

2018-01-16

Welcome to the National Ignition Facility at Lawrence Livermore National Laboratory, the world’s largest and most energetic laser system. It draws researchers from around the globe for experiments that can’t be conducted anywhere else on Earth. Let’s take a closer look.

Thin shell, high velocity inertial confinement fusion implosions on the national ignition facility.

PubMed

Ma, T; Hurricane, O A; Callahan, D A; Barrios, M A; Casey, D T; Dewald, E L; Dittrich, T R; Döppner, T; Haan, S W; Hinkel, D E; Berzak Hopkins, L F; Le Pape, S; MacPhee, A G; Pak, A; Park, H-S; Patel, P K; Remington, B A; Robey, H F; Salmonson, J D; Springer, P T; Tommasini, R; Benedetti, L R; Bionta, R; Bond, E; Bradley, D K; Caggiano, J; Celliers, P; Cerjan, C J; Church, J A; Dixit, S; Dylla-Spears, R; Edgell, D; Edwards, M J; Field, J; Fittinghoff, D N; Frenje, J A; Gatu Johnson, M; Grim, G; Guler, N; Hatarik, R; Herrmann, H W; Hsing, W W; Izumi, N; Jones, O S; Khan, S F; Kilkenny, J D; Knauer, J; Kohut, T; Kozioziemski, B; Kritcher, A; Kyrala, G; Landen, O L; MacGowan, B J; Mackinnon, A J; Meezan, N B; Merrill, F E; Moody, J D; Nagel, S R; Nikroo, A; Parham, T; Ralph, J E; Rosen, M D; Rygg, J R; Sater, J; Sayre, D; Schneider, M B; Shaughnessy, D; Spears, B K; Town, R P J; Volegov, P L; Wan, A; Widmann, K; Wilde, C H; Yeamans, C

2015-04-10

Experiments have recently been conducted at the National Ignition Facility utilizing inertial confinement fusion capsule ablators that are 175 and 165  μm in thickness, 10% and 15% thinner, respectively, than the nominal thickness capsule used throughout the high foot and most of the National Ignition Campaign. These three-shock, high-adiabat, high-foot implosions have demonstrated good performance, with higher velocity and better symmetry control at lower laser powers and energies than their nominal thickness ablator counterparts. Little to no hydrodynamic mix into the DT hot spot has been observed despite the higher velocities and reduced depth for possible instability feedthrough. Early results have shown good repeatability, with up to 1/2 the neutron yield coming from α-particle self-heating.

The National Direct-Drive Program: OMEGA to the National Ignition Facility

DOE PAGES

Regan, S. P.; Goncharov, V. N.; Sangster, T. C.; ...

2017-12-28

The goal of the National Direct-Drive Program is to demonstrate and understand the physics of laser direct drive (LDD). Efforts are underway on OMEGA for the 100-Gbar Campaign to demonstrate and understand the physics for hot-spot conditions and formation relevant for ignition at the 1-MJ scale, and at the National Ignition Facility to develop an understanding of the direct-drive physics at long scale lengths for the MJ Direct-Drive Campaign. For this paper the strategy of the National Direct-Drive Program is described; the requirements for the DT cryogenic fill-tube target being developed for OMEGA are presented; and preliminary LDD implosion measurementsmore » of hydrodynamic mixing seeded by laser imprint, the target-mounting stalk, and microscopic surface debris are reported.« less

The National Direct-Drive Program: OMEGA to the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Regan, S. P.; Goncharov, V. N.; Sangster, T. C.

The goal of the National Direct-Drive Program is to demonstrate and understand the physics of laser direct drive (LDD). Efforts are underway on OMEGA for the 100-Gbar Campaign to demonstrate and understand the physics for hot-spot conditions and formation relevant for ignition at the 1-MJ scale, and at the National Ignition Facility to develop an understanding of the direct-drive physics at long scale lengths for the MJ Direct-Drive Campaign. For this paper the strategy of the National Direct-Drive Program is described; the requirements for the DT cryogenic fill-tube target being developed for OMEGA are presented; and preliminary LDD implosion measurementsmore » of hydrodynamic mixing seeded by laser imprint, the target-mounting stalk, and microscopic surface debris are reported.« less

Novel characterization of capsule x-ray drive at the National Ignition Facility.

PubMed

MacLaren, S A; Schneider, M B; Widmann, K; Hammer, J H; Yoxall, B E; Moody, J D; Bell, P M; Benedetti, L R; Bradley, D K; Edwards, M J; Guymer, T M; Hinkel, D E; Hsing, W W; Kervin, M L; Meezan, N B; Moore, A S; Ralph, J E

2014-03-14

Indirect drive experiments at the National Ignition Facility are designed to achieve fusion by imploding a fuel capsule with x rays from a laser-driven hohlraum. Previous experiments have been unable to determine whether a deficit in measured ablator implosion velocity relative to simulations is due to inadequate models of the hohlraum or ablator physics. ViewFactor experiments allow for the first time a direct measure of the x-ray drive from the capsule point of view. The experiments show a 15%-25% deficit relative to simulations and thus explain nearly all of the disagreement with the velocity data. In addition, the data from this open geometry provide much greater constraints on a predictive model of laser-driven hohlraum performance than the nominal ignition target.

Early-Time Symmetry Tuning in the Presence of Cross-Beam Energy Transfer in ICF Experiments on the National Ignition Facility

DOE PAGES

Dewald, E. L.; Milovich, J. L.; Michel, P.; ...

2013-12-01

At the National Ignition Facility (NIF) we have successfully tuned the early time (~2 ns) lowest order Legendre mode (P 2) of the incoming radiation drive asymmetry of indirectly driven ignition capsule implosions by varying the inner power cone fraction. The measured P 2/P 0 sensitivity vs come fraction is similar to calculations, but a significant -15 to -20% P 2/P 0 offset was observed. This can be explained by a considerable early time laser energy transfer from the outer to the inner beams during the laser burn-through of the Laser Entrance Hole (LEH) windows and hohlraum fill gas whenmore » the LEH plasma is still dense and relatively cold.« less

Thin Shell, High Velocity Inertial Confinement Fusion Implosions on the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, T.; Hurricane, O. A.; Callahan, D. A.

Experiments have recently been conducted at the National Ignition Facility utilizing inertial confinement fusion capsule ablators that are 175 and 165 μm in thickness, 10% and 15% thinner, respectively, than the nominal thickness capsule used throughout the high foot and most of the National Ignition Campaign. These three-shock, high-adiabat, high-foot implosions have demonstrated good performance, with higher velocity and better symmetry control at lower laser powers and energies than their nominal thickness ablator counterparts. Little to no hydrodynamic mix into the DT hot spot has been observed despite the higher velocities and reduced depth for possible instability feedthrough. Earlier resultsmore » have shown good repeatability, with up to 1/2 the neutron yield coming from α-particle self-heating.« less

Precision shock tuning on the national ignition facility.

PubMed

Robey, H F; Celliers, P M; Kline, J L; Mackinnon, A J; Boehly, T R; Landen, O L; Eggert, J H; Hicks, D; Le Pape, S; Farley, D R; Bowers, M W; Krauter, K G; Munro, D H; Jones, O S; Milovich, J L; Clark, D; Spears, B K; Town, R P J; Haan, S W; Dixit, S; Schneider, M B; Dewald, E L; Widmann, K; Moody, J D; Döppner, T D; Radousky, H B; Nikroo, A; Kroll, J J; Hamza, A V; Horner, J B; Bhandarkar, S D; Dzenitis, E; Alger, E; Giraldez, E; Castro, C; Moreno, K; Haynam, C; LaFortune, K N; Widmayer, C; Shaw, M; Jancaitis, K; Parham, T; Holunga, D M; Walters, C F; Haid, B; Malsbury, T; Trummer, D; Coffee, K R; Burr, B; Berzins, L V; Choate, C; Brereton, S J; Azevedo, S; Chandrasekaran, H; Glenzer, S; Caggiano, J A; Knauer, J P; Frenje, J A; Casey, D T; Johnson, M Gatu; Séguin, F H; Young, B K; Edwards, M J; Van Wonterghem, B M; Kilkenny, J; MacGowan, B J; Atherton, J; Lindl, J D; Meyerhofer, D D; Moses, E

2012-05-25

Ignition implosions on the National Ignition Facility [J. D. Lindl et al., Phys. Plasmas 11, 339 (2004)] are underway with the goal of compressing deuterium-tritium fuel to a sufficiently high areal density (ρR) to sustain a self-propagating burn wave required for fusion power gain greater than unity. These implosions are driven with a very carefully tailored sequence of four shock waves that must be timed to very high precision to keep the fuel entropy and adiabat low and ρR high. The first series of precision tuning experiments on the National Ignition Facility, which use optical diagnostics to directly measure the strength and timing of all four shocks inside a hohlraum-driven, cryogenic liquid-deuterium-filled capsule interior have now been performed. The results of these experiments are presented demonstrating a significant decrease in adiabat over previously untuned implosions. The impact of the improved shock timing is confirmed in related deuterium-tritium layered capsule implosions, which show the highest fuel compression (ρR~1.0 g/cm(2)) measured to date, exceeding the previous record [V. Goncharov et al., Phys. Rev. Lett. 104, 165001 (2010)] by more than a factor of 3. The experiments also clearly reveal an issue with the 4th shock velocity, which is observed to be 20% slower than predictions from numerical simulation.

Spreaders, igniters, and burning shrubs: plant flammability explains novel fire dynamics in grass-invaded deserts.

PubMed

Fuentes-Ramirez, Andres; Veldman, Joseph W; Holzapfel, Claus; Moloney, Kirk A

2016-10-01

Novel fire regimes are an important cause and consequence of global environmental change that involve interactions among biotic, climatic, and human components of ecosystems. Plant flammability is key to these interactions, yet few studies directly measure flammability or consider how multiple species with different flammabilities interact to produce novel fire regimes. Deserts of the southwestern United States are an ideal system for exploring how novel fire regimes can emerge when fire-promoting species invade ecosystems comprised of species that did not evolve with fire. In these deserts, exotic annual grasses provide fuel continuity across landscapes that did not historically burn. These fires often ignite a keystone desert shrub, the fire-intolerant creosote bush, Larrea tridentata (DC.) Coville. Ignition of Larrea is likely catalyzed by fuels produced by native plants that grow beneath the shrubs. We hypothesize that invasive and native species exhibit distinct flammability characteristics that in combination determine spatial patterns of fire spread and intensity. We measured flammability metrics of Larrea, two invasive grasses, Schismus arabicus and Bromus madritensis, and two native plants, the sub-shrub Ambrosia dumosa and the annual herb Amsinckia menziesii. Results of laboratory experiments show that the grasses carry fire quickly (1.32 cm/s), but burn for short duration (0.5 min) at low temperatures. In contrast, native plants spread fire slowly (0.12 cm/s), but burn up to eight times longer (4 min) and produced hotter fires. Additional experiments on the ignition requirements of Larrea suggest that native plants burn with sufficient temperature and duration to ignite dead Larrea branches (time to ignition, 2 min; temperature at ignition 692°C). Once burning, these dead branches ignite living branches in the upper portions of the shrub. Our study provides support for a conceptual model in which exotic grasses are "spreaders" of fire and native plants growing beneath shrubs are "igniters" of dead Larrea branches. Once burning, flames produced by dead branches engulf the entire shrub, resulting in locally intense fires without historical precedent in this system. We suggest that fire models and conservation-focused management could be improved by incorporating the distinct flammability characteristics and spatial distributions of spreaders, igniters, and keystone shrubs. © 2016 by the Ecological Society of America.

14 CFR 23.1165 - Engine ignition systems.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Controls and Accessories § 23.1165 Engine ignition systems. (a) Each battery ignition system must be... ignition. (e) Each turbine engine ignition system must be independent of any electrical circuit that is not... commuter category airplanes, each turbine engine ignition system must be an essential electrical load. [Doc...

14 CFR 23.1165 - Engine ignition systems.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Controls and Accessories § 23.1165 Engine ignition systems. Link to an amendment published at 76 FR 75759... discharge of any battery used for engine ignition. (e) Each turbine engine ignition system must be... ignition systems. (f) In addition, for commuter category airplanes, each turbine engine ignition system...

The issue of FM to AM conversion on the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Browning, D F; Rothenberg, J E; Wilcox, R B

1998-08-13

The National Ignition Facility (NIF) baseline configuration for inertial confinement fusion requires phase modulation for two purposes. First, ~ 1Å of frequency modulation (FM) bandwidth at low modulation frequency is required to suppress buildup of Stimulated Brioullin Scattering (SBS) in the large aperture laser optics. Also ~ 3 Å or more bandwidth at high modulation frequency is required for smoothing of the speckle pattern illuminating the target by the smoothing by spectral dispersion method (SSD). Ideally, imposition of bandwidth by pure phase modulation does not affect the beam intensity. However, as a result of a large number of effects, themore » FM converts to amplitude modulation (AM). In general this adversely affects the laser performance, e.g. by reducing the margin against damage to the optics. In particular, very large conversion of FM to AM has been observed in the NIF all-fiber master oscillator and distribution systems. The various mechanisms leading to AM are analyzed and approaches to minimizing their effects are discussed.« less

A neutron activation spectrometer and neutronic experimental platform for the National Ignition Facility (invited)

NASA Astrophysics Data System (ADS)

Yeamans, C. B.; Gharibyan, N.

2016-11-01

At the National Ignition Facility, the diagnostic instrument manipulator-based neutron activation spectrometer is used as a diagnostic of implosion performance for inertial confinement fusion experiments. Additionally, it serves as a platform for independent neutronic experiments and may be connected to fast recording systems for neutron effect tests on active electronics. As an implosion diagnostic, the neutron activation spectrometers are used to quantify fluence of primary DT neutrons, downscattered neutrons, and neutrons above the primary DT neutron energy created by reactions of upscattered D and T in flight. At a primary neutron yield of 1015 and a downscattered fraction of neutrons in the 10-12 MeV energy range of 0.04, the downscattered neutron fraction can be measured to a relative uncertainty of 8%. Significant asymmetries in downscattered neutrons have been observed. Spectrometers have been designed and fielded to measure the tritium-tritium and deuterium-tritium neutron outputs simultaneously in experiments using DT/TT fusion ratio as a direct measure of mix of ablator into the gas.

High-energy (> 70 KeV) x-ray conversion efficiency measurement on the ARC laser at the National Ignition Facility

DOE PAGES

Chen, Hui; Hermann, M. R.; Kalantar, D. H.; ...

2017-03-16

Here, the Advanced Radiographic Capability (ARC) laser system at the National Ignition Facility (NIF) is designed to ultimately provide eight beamlets with a pulse duration adjustable from 1 to 30 ps, and energies up to 1.5 kJ per beamlet. Currently, four beamlets have been commissioned. In the first set of 6 commissioning target experiments, the individual beamlets were fired onto gold foil targets with energy up to 1 kJ per beamlet at 20–30 ps pulse length. The x-ray energy distribution and pulse duration were measured, yielding energy conversion efficiencies of 4–9 × 10 –4 for x-rays with energies greater thanmore » 70 keV. With greater than 3 J of such x-rays, ARC provides a high-precision x-ray backlighting capability for upcoming inertial confinement fusion and high-energy-density physics experiments on NIF.« less

Simulated performance of the optical Thomson scattering diagnostic designed for the National Ignition Facility.

PubMed

Ross, J S; Datte, P; Divol, L; Galbraith, J; Froula, D H; Glenzer, S H; Hatch, B; Katz, J; Kilkenny, J; Landen, O; Manuel, A M; Molander, W; Montgomery, D S; Moody, J D; Swadling, G; Weaver, J

2016-11-01

An optical Thomson scattering diagnostic has been designed for the National Ignition Facility to characterize under-dense plasmas. We report on the design of the system and the expected performance for different target configurations. The diagnostic is designed to spatially and temporally resolve the Thomson scattered light from laser driven targets. The diagnostic will collect scattered light from a 50 × 50 × 200 μm volume. The optical design allows operation with different probe laser wavelengths. A deep-UV probe beam (λ 0 = 210 nm) will be used to Thomson scatter from electron plasma densities of ∼5 × 10 20 cm -3 while a 3ω probe will be used for plasma densities of ∼1 × 10 19 cm -3 . The diagnostic package contains two spectrometers: the first to resolve Thomson scattering from ion acoustic wave fluctuations and the second to resolve scattering from electron plasma wave fluctuations. Expected signal levels relative to background will be presented for typical target configurations (hohlraums and a planar foil).

A neutron activation spectrometer and neutronic experimental platform for the National Ignition Facility (invited).

PubMed

Yeamans, C B; Gharibyan, N

2016-11-01

At the National Ignition Facility, the diagnostic instrument manipulator-based neutron activation spectrometer is used as a diagnostic of implosion performance for inertial confinement fusion experiments. Additionally, it serves as a platform for independent neutronic experiments and may be connected to fast recording systems for neutron effect tests on active electronics. As an implosion diagnostic, the neutron activation spectrometers are used to quantify fluence of primary DT neutrons, downscattered neutrons, and neutrons above the primary DT neutron energy created by reactions of upscattered D and T in flight. At a primary neutron yield of 10 15 and a downscattered fraction of neutrons in the 10-12 MeV energy range of 0.04, the downscattered neutron fraction can be measured to a relative uncertainty of 8%. Significant asymmetries in downscattered neutrons have been observed. Spectrometers have been designed and fielded to measure the tritium-tritium and deuterium-tritium neutron outputs simultaneously in experiments using DT/TT fusion ratio as a direct measure of mix of ablator into the gas.

Performance evaluation of bimodal thermite composites : nano- vs miron-scale particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, K. M.; Pantoya, M.; Son, S. F.

2004-01-01

In recent years many studies of metastable interstitial composites (MIC) have shown vast combustion improvements over traditional thermite materials. The main difference between these two materials is the size of the fuel particles in the mixture. Decreasing the fuel size from the micron to nanometer range significantly increases the combustion wave speed and ignition sensitivity. Little is known, however, about the critical level of nano-sized fuel particles needed to enhance the performance of the traditional thermite. Ignition sensitivity experiments were performed using Al/MoO{sub 3} pellets at a theoretical maximum density of 50% (2 g/cm{sup 3}). The Al fuel particles weremore » prepared as bi-modal size distributions with micron (i.e., 4 and 20 {micro}m diameter) and nano-scale Al particles. The micron-scale Al was replaced in 10% increments by 80 nm Al particles until the fuel was 100% 80 nm Al. These bi-modal distributions allow the unique characteristics of nano-scale materials to be better understood. The pellets were ignited using a 50-W CO{sub 2} laser. High speed imaging diagnostics were used to measure ignition delay times, and micro-thermocouples were used to measure ignition temperatures. Combustion wave speeds were also examined.« less

National Ignition Facility project acquisition plan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Callaghan, R.W.

The purpose of this National Ignition Facility Acquisition Plan is to describe the overall procurement strategy planned for the National Ignition Facility (NIF) Project. The scope of the plan describes the procurement activities and acquisition strategy for the following phases of the NIF Project, each of which receives either plant and capital equipment (PACE) or other project cost (OPC) funds: Title 1 and 2 design and Title 3 engineering (PACE); Optics manufacturing facilitization and pilot production (OPC); Convention facility construction (PACE); Procurement, installation, and acceptance testing of equipment (PACE); and Start-up (OPC). Activities that are part of the base Inertialmore » Confinement Fusion (ICF) Program are not included in this plan. The University of California (UC), operating Lawrence Livermore National Laboratory (LLNL) and Los Alamos National Laboratory, and Lockheed-Martin, which operates Sandia National Laboratory (SNL) and the University of Rochester Laboratory for Laser Energetics (UR-LLE), will conduct the acquisition of needed products and services in support of their assigned responsibilities within the NIF Project structure in accordance with their prime contracts with the Department of Energy (DOE). LLNL, designated as the lead Laboratory, will have responsibility for all procurements required for construction, installation, activation, and startup of the NIF.« less

Scientific and technological advancements in inertial fusion energy

DOE PAGES

Hinkel, D. E.

2013-09-26

Scientific advancements in inertial fusion energy (IFE) were reported on at the IAEA Fusion Energy Conference, October 2012. Results presented transect the different ways to assemble the fuel, different scenarios for igniting the fuel, and progress in IFE technologies. The achievements of the National Ignition Campaign within the USA, using the National Ignition Facility (NIF) to indirectly drive laser fusion, have found beneficial the achievements in other IFE arenas such as directly driven laser fusion and target fabrication. Moreover, the successes at NIF have pay-off to alternative scenarios such as fast ignition, shock ignition, and heavy-ion fusion as well asmore » to directly driven laser fusion. As a result, this synergy is summarized here, and future scientific studies are detailed.« less

Assessment and mitigation of diagnostic-generated electromagnetic interference at the National Ignition Facilitya)

NASA Astrophysics Data System (ADS)

Brown, C. G.; Ayers, J.; Felker, B.; Ferguson, W.; Holder, J. P.; Nagel, S. R.; Piston, K. W.; Simanovskaia, N.; Throop, A. L.; Chung, M.; Hilsabeck, T.

2012-10-01

Electromagnetic interference (EMI) is an ever-present challenge at laser facilities such as the National Ignition Facility (NIF). The major source of EMI at such facilities is laser-target interaction that can generate intense electromagnetic fields within, and outside of, the laser target chamber. In addition, the diagnostics themselves can be a source of EMI, even interfering with themselves. In this paper we describe EMI generated by ARIANE and DIXI, present measurements, and discuss effects of the diagnostic-generated EMI on ARIANE's CCD and on a PMT nearby DIXI. Finally we present some of the efforts we have made to mitigate the effects of diagnostic-generated EMI on NIF diagnostics.

124Xe(n,γ)125Xe and 124Xe(n,2n)123Xe measurements for National Ignition Facility

NASA Astrophysics Data System (ADS)

Bhike, Megha; Ludin, Nurin; Tornow, Werner

2015-05-01

The cross section for the 124Xe(n,γ)125Xe reaction has been measured for the first time for neutron energies above 100 keV. In addition, the 124Xe(n,2n)123Xe reaction has been studied between threshold and 14.8 MeV. The results of these measurements provide sensitive diagnostic tools for investigating properties of the inertial confinement fusion plasma in Deuterium-Tritium (DT) capsules at the National Ignition Facility (NIF) located at Lawrence Livermore National Laboratory.

H_Hyd_Shktub_Mshock_III, JJJ, KKK (S01,S02,S03) on the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Desjardins, Tiffany; Schmidt, Derek William; Di Stefano, Carlos

2017-12-15

These experiments are the first experiments in the Mshock campaign at the National Ignition Facility. The experiment is scheduled to be conducted on Dec. 14, 2017. The goal of the Mshock campaign is to study feedthrough dynamics of the Richtmyer- Meshkov instability in a thin layer. These dynamics will be studied in both a reshock configuration (initially) and then in a multi-shock configuration where it is planned to reshock the RM instability up to 3 times (four shocks total).

Modeling the National Ignition Facility neutron imaging system.

PubMed

Wilson, D C; Grim, G P; Tregillis, I L; Wilke, M D; Patel, M V; Sepke, S M; Morgan, G L; Hatarik, R; Loomis, E N; Wilde, C H; Oertel, J A; Fatherley, V E; Clark, D D; Fittinghoff, D N; Bower, D E; Schmitt, M J; Marinak, M M; Munro, D H; Merrill, F E; Moran, M J; Wang, T-S F; Danly, C R; Hilko, R A; Batha, S H; Frank, M; Buckles, R

2010-10-01

Numerical modeling of the neutron imaging system for the National Ignition Facility (NIF), forward from calculated target neutron emission to a camera image, will guide both the reduction of data and the future development of the system. Located 28 m from target chamber center, the system can produce two images at different neutron energies by gating on neutron arrival time. The brighter image, using neutrons near 14 MeV, reflects the size and symmetry of the implosion "hot spot." A second image in scattered neutrons, 10-12 MeV, reflects the size and symmetry of colder, denser fuel, but with only ∼1%-7% of the neutrons. A misalignment of the pinhole assembly up to ±175 μm is covered by a set of 37 subapertures with different pointings. The model includes the variability of the pinhole point spread function across the field of view. Omega experiments provided absolute calibration, scintillator spatial broadening, and the level of residual light in the down-scattered image from the primary neutrons. Application of the model to light decay measurements of EJ399, BC422, BCF99-55, Xylene, DPAC-30, and Liquid A suggests that DPAC-30 and Liquid A would be preferred over the BCF99-55 scintillator chosen for the first NIF system, if they could be fabricated into detectors with sufficient resolution.

The physics basis for ignition using indirect-drive targets on the National Ignition Facility

NASA Astrophysics Data System (ADS)

Lindl, John D.; Amendt, Peter; Berger, Richard L.; Glendinning, S. Gail; Glenzer, Siegfried H.; Haan, Steven W.; Kauffman, Robert L.; Landen, Otto L.; Suter, Laurence J.

2004-02-01

The 1990 National Academy of Science final report of its review of the Inertial Confinement Fusion Program recommended completion of a series of target physics objectives on the 10-beam Nova laser at the Lawrence Livermore National Laboratory as the highest-priority prerequisite for proceeding with construction of an ignition-scale laser facility, now called the National Ignition Facility (NIF). These objectives were chosen to demonstrate that there was sufficient understanding of the physics of ignition targets that the laser requirements for laboratory ignition could be accurately specified. This research on Nova, as well as additional research on the Omega laser at the University of Rochester, is the subject of this review. The objectives of the U.S. indirect-drive target physics program have been to experimentally demonstrate and predictively model hohlraum characteristics, as well as capsule performance in targets that have been scaled in key physics variables from NIF targets. To address the hohlraum and hydrodynamic constraints on indirect-drive ignition, the target physics program was divided into the Hohlraum and Laser-Plasma Physics (HLP) program and the Hydrodynamically Equivalent Physics (HEP) program. The HLP program addresses laser-plasma coupling, x-ray generation and transport, and the development of energy-efficient hohlraums that provide the appropriate spectral, temporal, and spatial x-ray drive. The HEP experiments address the issues of hydrodynamic instability and mix, as well as the effects of flux asymmetry on capsules that are scaled as closely as possible to ignition capsules (hydrodynamic equivalence). The HEP program also addresses other capsule physics issues associated with ignition, such as energy gain and energy loss to the fuel during implosion in the absence of alpha-particle deposition. The results from the Nova and Omega experiments approach the NIF requirements for most of the important ignition capsule parameters, including drive temperature, drive symmetry, and hydrodynamic instability. This paper starts with a review of the NIF target designs that have formed the motivation for the goals of the target physics program. Following that are theoretical and experimental results from Nova and Omega relevant to the requirements of those targets. Some elements of this work were covered in a 1995 review of indirect-drive [J. D. Lindl, ``Development of the indirect-drive approach to inertial confinement fusion and the target physics basis for ignition and gain,'' Phys. Plasmas 2, 3933 (1995)]. In order to present as complete a picture as possible of the research that has been carried out on indirect drive, key elements of that earlier review are also covered here, along with a review of work carried out since 1995.

A fail safe laser activated switch used as an emergency control link at the Langley Vortex Research Facility

NASA Technical Reports Server (NTRS)

Kassel, P. C., Jr.

1978-01-01

A fail safe light activated switch was used as an emergency control link at the Langley Vortex Research Facility. In this facility aircraft models were towed through a still air test chamber by a gasoline powered vehicle which was launched from one end of a 427-meter track and attained velocities to 31 m/sec in the test chamber. A 5 mW HeNe laser with a mechanical copper provided a connecting link with the moving tow vehicle on which a silicon photodiode receiver with a specially designed amplifier provided a fail safe switching action. This system provided an emergency means of stopping the vehicle by turning off the laser to interrupt the power to the vehicle ignition and brake release systems.

Inertial Confinement Fusion as an Extreme Example of Dynamic Compression

NASA Astrophysics Data System (ADS)

Moses, E.

2013-06-01

Initiating and controlling thermonuclear burn at the national ignition facility (NIF) will require the manipulation of matter to extreme energy densities. We will discuss recent advances in both controlling the dynamic compression of ignition targets and our understanding of the physical states and processes leading to ignition. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory in part under Contract W-7405-Eng-48 and in part under Contract DE-AC52-07NA27344.

Atomic Scale Mixing for Inertial Confinement Fusion Associated Hydro Instabilities

DTIC Science & Technology

2013-01-26

observe that the obvious step of RT validation using NIF or Omega laser data does not address themultimode, mode coupling RTgrowth stage, as the...ignition facility, Phys. Plasmas 18 (2011) 051001. [2] W. Goldstein, R. Rosner, Workshop on the Science of Fusion Ignition on NIF , Technical Report LLNL-TR...11 (2004) 339e491. [6] S.P. Regan, R. Epstein, B.A. Hammel, L.J. Suter, J. Ralph, et al., Hot-spot mix in ignition-scale implosions on the NIF , Phys

Development of an Aerosol Loading Technique for Ignition Time Measurements in Shock Tubes

DTIC Science & Technology

2007-08-01

authors do not follow the 200 word limit 14. SUBJECT TERMS Aerosol Shock Tube, Ignition Delay Time, n -Dodecane, Aerosol 17. SECURITY CLASSIFICATION...time measurements of n -dodecane/O2/argon mixtures. These measurements are found to be consistent with those made in our heated shock tube facility. (a...Papers published in peer-reviewed journals ( N /A for none) S. S. Vasu, D. F. Davidson, R. K. Hanson, “Shock Tube Measurements of Jet Fuel Ignition

Electrical Arc Ignition Testing for Constellation Program

NASA Technical Reports Server (NTRS)

Sparks, Kyle; Gallus, Timothy; Smith, Sarah

2009-01-01

NASA Johnson Space Center (JSC) Materials and Processes Branch requested that NASA JSC White Sands Test Facility (WSTF) perform testing for the Constellation Program to evaluate the hazard of electrical arc ignition of materials that could be in close proximity to batteries. Specifically, WSTF was requested to perform wire-break electrical arc tests to determine the current threshold for ignition of generic cotton woven fabric samples with a fixed voltage of 3.7 V, a common voltage for hand-held electrical devices. The wire-break test was developed during a previous test program to evaluate the hazard of electrical arc ignition inside the Extravehicular Mobility Unit [1].

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rozanov, V. B., E-mail: rozanov@sci.lebedev.ru; Vergunova, G. A., E-mail: verg@sci.lebedev.ru

The main parameters of compression of a target and tendencies at change in the irradiation conditions are determined by analyzing the published results of experiments at the megajoule National Ignition Facility (NIF) on the compression of capsules in indirect-irradiation targets by means of the one-dimensional RADIAN program in the spherical geometry. A possible version of the “failure of ignition” of an indirect-irradiation target under the NIF conditions is attributed to radiation transfer. The application of onedimensional model to analyze the National Ignition Campaign (NIC) experiments allows identifying conditions corresponding to the future ignition regime and distinguishing them from conditions undermore » which ignition does not occur.« less

Combined neutron and x-ray imaging at the National Ignition Facility (invited)

DOE PAGES

Danly, C. R.; Christensen, K.; Fatherley, Valerie E.; ...

2016-10-11

X-ray and neutrons are commonly used to image Inertial Confinement Fusion implosions, providing key diagnostic information on the fuel assembly of burning DT fuel. The x-ray and neutron data provided are complementary as the production of neutrons and x-rays occur from different physical processes, but typically these two images are collected from different views with no opportunity for co-registration of the two images. Neutrons are produced where the DT fusion fuel is burning; X-rays are produced in regions corresponding to high temperatures. Processes such as mix of ablator material into the hotspot can result in increased x-ray production and decreasedmore » neutron production but can only be confidently observed if the two images are collected along the same line of sight and co-registered. To allow direct comparison of x-ray and neutron data, a Combined Neutron X-ray Imaging system has been tested at Omega and installed at the National Ignition Facility to collect an x-ray image along the currently installed neutron imaging line-of-sight. Here, this system is described, and initial results are presented along with prospects for definitive coregistration of the images.« less

Combined neutron and x-ray imaging at the National Ignition Facility (invited).

PubMed

Danly, C R; Christensen, K; Fatherley, V E; Fittinghoff, D N; Grim, G P; Hibbard, R; Izumi, N; Jedlovec, D; Merrill, F E; Schmidt, D W; Simpson, R A; Skulina, K; Volegov, P L; Wilde, C H

2016-11-01

X-ray and neutrons are commonly used to image inertial confinement fusion implosions, providing key diagnostic information on the fuel assembly of burning deuterium-tritium (DT) fuel. The x-ray and neutron data provided are complementary as the production of neutrons and x-rays occurs from different physical processes, but typically these two images are collected from different views with no opportunity for co-registration of the two images. Neutrons are produced where the DT fusion fuel is burning; X-rays are produced in regions corresponding to high temperatures. Processes such as mix of ablator material into the hotspot can result in increased x-ray production and decreased neutron production but can only be confidently observed if the two images are collected along the same line of sight and co-registered. To allow direct comparison of x-ray and neutron data, a combined neutron x-ray imaging system has been tested at Omega and installed at the National Ignition Facility to collect an x-ray image along the currently installed neutron imaging line of sight. This system is described, and initial results are presented along with prospects for definitive coregistration of the images.

Capsule physics comparison of National Ignition Facility implosion designs using plastic, high density carbon, and beryllium ablators

NASA Astrophysics Data System (ADS)

Clark, D. S.; Kritcher, A. L.; Yi, S. A.; Zylstra, A. B.; Haan, S. W.; Weber, C. R.

2018-03-01

Indirect drive implosion experiments on the National Ignition Facility (NIF) [E. I. Moses et al., Phys. Plasmas 16, 041006 (2009)] have now tested three different ablator materials: glow discharge polymer plastic, high density carbon, and beryllium. How do these different ablators compare in current and proposed implosion experiments on NIF? What are the relative advantages and disadvantages of each? This paper compares these different ablator options in capsule-only simulations of current NIF experiments and potential future designs. The simulations compare the impact of the capsule fill tube, support tent, and interface surface roughness for each case, as well as all perturbations in combination. According to the simulations, each ablator is impacted by the various perturbation sources differently, and each material poses unique challenges in the pursuit of ignition on NIF.

Benefits of Moderate-Z Ablators for Direct-Drive Inertial Confinement Fusion

NASA Astrophysics Data System (ADS)

Lafon, M.; Betti, R.; Anderson, K. S.; Collins, T. J. B.; Skupsky, S.; McKenty, P. W.

2014-10-01

Control of hydrodynamic instabilities and DT-fuel preheating by hot electrons produced by laser-plasma interaction is crucial in inertial confinement fusion. Moderate- Z ablators have been shown to reduce the laser imprinting on target and suppress the generation of hot electrons from the two-plasmon-decay instability. These results have motivated the use of ablators of higher- Z than pure plastic in direct-drive-ignition target designs for the National Ignition Facility (NIF). Two-dimensional radiation-hydrodynamic simulations assess the robustness of these ignition designs to laser imprint and capsule nonuniformities. The complex behavior of the hydrodynamic stability of mid- Z ablators is investigated through single and multimode simulations. A polar-drive configuration is developed within the NIF Laser System specifications for each ablator material. The use of multilayer ablators is also investigated to enhance the hydrodynamic stability. Results indicate that ignition target designs using mid- Z ablators exhibit good hydrodynamic properties, leading to high target gain for direct-drive implosions on the NIF. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944 and the Office of Fusion Energy Sciences Number DE-FG02-04ER54786.

Effects of H{sub 2} enrichment on the propagation characteristics of CH{sub 4}-air triple flames

DOE Office of Scientific and Technical Information (OSTI.GOV)

Briones, Alejandro M.; Aggarwal, Suresh K.; Katta, Viswanath R.

The effects of H{sub 2} enrichment on the propagation of laminar CH{sub 4}-air triple flames in axisymmetric coflowing jets are numerically investigated. A comprehensive, time-dependent computational model, which employs a detailed description of chemistry and transport, is used to simulate the transient ignition and flame propagation phenomena. Flames are ignited in a jet-mixing layer far downstream of the burner. Following ignition, a well-defined triple flame is formed that propagates upstream along the stoichiometric mixture fraction line with a nearly constant displacement velocity. As the flame approaches the burner, it transitions to a double flame, and subsequently to a burner-stabilized nonpremixedmore » flame. Predictions are validated using measurements of the displacement flame velocity. As the H{sub 2} concentration in the fuel blend is increased, the displacement flame velocity and local triple flame speed increase progressively due to the enhanced chemical reactivity, diffusivity, and preferential diffusion caused by H{sub 2} addition. In addition, the flammability limits associated with the triple flames are progressively extended with the increase in H{sub 2} concentration. The flame structure and flame dynamics are also markedly modified by H{sub 2} enrichment, which substantially increases the flame curvature and mixture fraction gradient, as well as the hydrodynamic and curvature-induced stretch near the triple point. For all the H{sub 2}-enriched methane-air flames investigated in this study, there is a negative correlation between flame speed and stretch, with the flame speed decreasing almost linearly with stretch, consistent with previous studies. The H{sub 2} addition also modifies the flame sensitivity to stretch, as it decreases the Markstein number (Ma), implying an increased tendency toward diffusive-thermal instability (i.e. Ma {yields} 0). These results are consistent with the previously reported experimental results for outwardly propagating spherical flames burning a mixture of natural gas and hydrogen. (author)« less

Computational Analyses in Support of Sub-scale Diffuser Testing for the A-3 Facility. Part 2; Unsteady Analyses and Risk Assessment

NASA Technical Reports Server (NTRS)

Ahuja, Vineet; Hosangadi, Ashvin; Allgood, Daniel

2008-01-01

Simulation technology can play an important role in rocket engine test facility design and development by assessing risks, providing analysis of dynamic pressure and thermal loads, identifying failure modes and predicting anomalous behavior of critical systems. This is especially true for facilities such as the proposed A-3 facility at NASA SSC because of a challenging operating envelope linked to variable throttle conditions at relatively low chamber pressures. Design Support of the feasibility of operating conditions and procedures is critical in such cases due to the possibility of startup/shutdown transients, moving shock structures, unsteady shock-boundary layer interactions and engine and diffuser unstart modes that can result in catastrophic failure. Analyses of such systems is difficult due to resolution requirements needed to accurately capture moving shock structures, shock-boundary layer interactions, two-phase flow regimes and engine unstart modes. In a companion paper, we will demonstrate with the use of CFD, steady analyses advanced capability to evaluate supersonic diffuser and steam ejector performance in the sub-scale A-3 facility. In this paper we will address transient issues with the operation of the facility especially at startup and shutdown, and assess risks related to afterburning due to the interaction of a fuel rich plume with oxygen that is a by-product of the steam ejectors. The primary areas that will be addressed in this paper are: (1) analyses of unstart modes due to flow transients especially during startup/ignition, (2) engine safety during the shutdown process (3) interaction of steam ejectors with the primary plume i.e. flow transients as well as probability of afterburning. In this abstract we discuss unsteady analyses of the engine shutdown process. However, the final paper will include analyses of a staged startup, drawdown of the engine test cell pressure, and risk assessment of potential afterburning in the facility. Unsteady simulations have been carried out to study the engine shutdown process in the facility and understand the physics behind the interactions between the steam ejectors, the test cell and the supersonic diffuser. As a first approximation, to understand the dominant unsteady mechanisms in the engine test cell and the supersonic diffuser, the turning duct in the facility was removed. As the engine loses power a rarefaction wave travels downstream that disrupts the shock cell structure in the supersonic diffuser. Flow from the test cell is seen to expand into the supersonic diffuser section and re-pressurizes the area around the nozzle along with a upstream traveling compression wave that emanates from near the first stage ejectors. Flow from the first stage ejector expands to the center of the duct and a new shock train is formed between the first and second stage ejectors. Both stage ejectors keep the facility pressurized and prevent any large amplitude pressure fluctuations from affecting the engine nozzle. The resultant pressure loads the nozzle experiences in the shutdown process are small.

Transient Pressure Test Article Test Program

NASA Technical Reports Server (NTRS)

Vibbart, Charles M.

1989-01-01

The Transient Pressure Test Article (TPTA) test program is being conducted at a new test facility located in the East Test Area at the National Aeronautics and Space Administration's (NASA's) Marshall Space Flight Center (MSFC) in Huntsville, Alabama. This facility, along with the special test equipment (STE) required for facility support, was constructed specifically to test and verify the sealing capability of the Redesigned Solid Rocket Motor (RSRM) field, igniter, and nozzle joints. The test article consists of full scale RSRM hardware loaded with inert propellant and assembled in a short stack configuration. The TPTA is pressurized by igniting a propellant cartridge capable of inducing a pressure rise rate which stimulates the ignition transient that occurs during launch. Dynamic loads are applied during the pressure cycle to simulate external tank attach (ETA) strut loads present on the ETA ring. Sealing ability of the redesigned joints is evaluated under joint movement conditions produced by these combined loads since joint sealing ability depends on seal resilience velocity being greater than gap opening velocity. Also, maximum flight dynamic loads are applied to the test article which is either pressurized to 600 psia using gaseous nitrogen (GN2) or applied to the test article as the pressure decays inside the test article on the down cycle after the ignition transient cycle. This new test facility is examined with respect to its capabilities. In addition, both the topic of test effectiveness versus space vehicle flight performance and new aerospace test techniques, as well as a comparison between the old SRM design and the RSRM are presented.

Auto-ignitions of a methane/air mixture at high and intermediate temperatures

NASA Astrophysics Data System (ADS)

Leschevich, V. V.; Martynenko, V. V.; Penyazkov, O. G.; Sevrouk, K. L.; Shabunya, S. I.

2016-09-01

A rapid compression machine (RCM) and a shock tube (ST) have been employed to study ignition delay times of homogeneous methane/air mixtures at intermediate-to-high temperatures. Both facilities allow measurements to be made at temperatures of 900-2000 K, at pressures of 0.38-2.23 MPa, and at equivalence ratios of 0.5, 1.0, and 2.0. In ST experiments, nitrogen served as a diluent gas, whereas in RCM runs the diluent gas composition ranged from pure nitrogen to pure argon. Recording pressure, UV, and visible emissions identified the evolution of chemical reactions. Correlations of ignition delay time were generated from the data for each facility. At temperatures below 1300 K, a significant reduction of average activation energy from 53 to 15.3 kcal/mol was obtained. Moreover, the RCM data showed significant scatter that dramatically increased with decreasing temperature. An explanation for the abnormal scatter in the data was proposed based on the high-speed visualization of auto-ignition phenomena and experiments performed with oxygen-free and fuel-free mixtures. It is proposed that the main reason for such a significant reduction of average activation energy is attributable to the premature ignition of ultrafine particles in the reactive mixture.

The National Ignition Facility Diagnostic Set at the Completion of the National Ignition Campaign, September 2012

DOE PAGES

Kilkenny, J. D.; Bell, P. M.; Bradley, D. K.; ...

2016-01-06

At the completion of the National Ignition Campaign (NIC), the National Ignition Facility (NIF) had about 36 different types of diagnostics. These were based on several decades of development on Nova and OMEGA and involved the whole U.S. inertial confinement fusion community. In 1994, the Joint Central Diagnostic Team documented a plan for a limited set of NIF diagnostics in the NIF Conceptual Design Report. Two decades later, these diagnostics, and many others, were installed workhorse tools for all users of NIF. We give a short description of each of the 36 different types of NIC diagnostics grouped by themore » function of the diagnostics, namely, target drive, target response and target assembly, stagnation, and burn. A comparison of NIF diagnostics with the Nova diagnostics shows that the NIF diagnostic capability is broadly equivalent to that of Nova in 1999. Although NIF diagnostics have a much greater degree of automation and rigor than Nova’s, new diagnostics are limited such as the higher-speed X-ray imager. Lastly, recommendations for future diagnostics on the NIF are discussed.« less

Advances in NIF Shock Timing Experiments

NASA Astrophysics Data System (ADS)

Robey, Harry

2012-10-01

Experiments are underway to tune the shock timing of capsule implosions on the National Ignition Facility (NIF). These experiments use a modified cryogenic hohlraum geometry designed to precisely match the performance of ignition hohlraums. The targets employ a re-entrant Au cone to provide optical access to multiple shocks as they propagate in the liquid deuterium-filled capsule interior. The strength and timing of all four shocks is diagnosed with VISAR (Velocity Interferometer System for Any Reflector). Experiments are now routinely conducted in a mirrored keyhole geometry, which allows for simultaneous diagnosis of the shock timing at both the hohlraum pole and equator. Further modifications are being made to improve the surrogacy to ignition hohlraums by replacing the standard liquid deuterium (D2) capsule fill with a deuterium-tritium (DT) ice layer. These experiments will remove any possible surrogacy difference between D2 and DT as well as incorporate the physics of shock release from the ice layer, which is absent in current experiments. Experimental results and comparisons with numerical simulation are presented.

Demonstration of Fuel Hot-Spot Pressure in Excess of 50 Gbar for Direct-Drive, Layered Deuterium-Tritium Implosions on OMEGA.

PubMed

Regan, S P; Goncharov, V N; Igumenshchev, I V; Sangster, T C; Betti, R; Bose, A; Boehly, T R; Bonino, M J; Campbell, E M; Cao, D; Collins, T J B; Craxton, R S; Davis, A K; Delettrez, J A; Edgell, D H; Epstein, R; Forrest, C J; Frenje, J A; Froula, D H; Gatu Johnson, M; Glebov, V Yu; Harding, D R; Hohenberger, M; Hu, S X; Jacobs-Perkins, D; Janezic, R; Karasik, M; Keck, R L; Kelly, J H; Kessler, T J; Knauer, J P; Kosc, T Z; Loucks, S J; Marozas, J A; Marshall, F J; McCrory, R L; McKenty, P W; Meyerhofer, D D; Michel, D T; Myatt, J F; Obenschain, S P; Petrasso, R D; Radha, P B; Rice, B; Rosenberg, M J; Schmitt, A J; Schmitt, M J; Seka, W; Shmayda, W T; Shoup, M J; Shvydky, A; Skupsky, S; Solodov, A A; Stoeckl, C; Theobald, W; Ulreich, J; Wittman, M D; Woo, K M; Yaakobi, B; Zuegel, J D

2016-07-08

A record fuel hot-spot pressure P_{hs}=56±7  Gbar was inferred from x-ray and nuclear diagnostics for direct-drive inertial confinement fusion cryogenic, layered deuterium-tritium implosions on the 60-beam, 30-kJ, 351-nm OMEGA Laser System. When hydrodynamically scaled to the energy of the National Ignition Facility, these implosions achieved a Lawson parameter ∼60% of the value required for ignition [A. Bose et al., Phys. Rev. E 93, 011201(R) (2016)], similar to indirect-drive implosions [R. Betti et al., Phys. Rev. Lett. 114, 255003 (2015)], and nearly half of the direct-drive ignition-threshold pressure. Relative to symmetric, one-dimensional simulations, the inferred hot-spot pressure is approximately 40% lower. Three-dimensional simulations suggest that low-mode distortion of the hot spot seeded by laser-drive nonuniformity and target-positioning error reduces target performance.

Deuterium-Tritium Beta-Layering Within a National Ignition Facility Scale Polymer Target in the LANL Cryogenic Pressure Loader

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ebey, Peter S.; Dole, James M.; Geller, Drew A.

2005-11-15

Beta-layering, the process of beta-decay heat-driven mass redistribution, has been demonstrated in a deuterium-tritium (D-T)-filled polymer sphere of the type required for fusion ignition experiments at the National Ignition Facility. This is the first report, to the best of the authors' knowledge, of a D-T layer formed in a permeation-filled sphere. The 2-mm-diam sphere was filled with D-T by permeation; cooled to cryogenic temperatures while in the high-pressure permeation vessel; and, while cold, removed to an optical axis where the D-T was frozen, melted, and beta-layered in a series of experiments over several weeks' time. This work was performed inmore » the Los Alamos National Laboratory cryogenic pressure loader system. The beta-layering time constant was 24.0 {+-} 2.5 min, less than the theoretical value of 26.8 min, and not showing the significant increase due to build-up of {sup 3}He often observed in beta-layered samples. Supercooling of the liquid D-T was observed. Neither the polymer target nor its tenting material showed visual signs of degradation after 5 weeks of exposure to D-T. Small external thermal gradients were used to shift the D-T material back and forth within the sphere.« less

Recent progress on the National Ignition Facility advanced radiographic capability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wegner, P.; Bowers, M.; Chen, H.

2016-01-08

The National Ignition Facility (NIF) is a megajoule (million-joule)-class laser and experimental facility built for Stockpile Stewardship and High Energy Density (HED) science research [1]. Up to several times a day, 192 laser pulses from NIF's 192 laser beamlines converge on a millimeter-scale target located at the center of the facility's 10-meter diameter target chamber. The carefully synchronized pulses, typically a few nanoseconds (billionths of a second) in duration and co-times to better than 20 picoseconds (trillionths of a second), a deliver a combined energy of up to 1.8 megajoules and a peak power of 500 terawatts (trillion watts). Furthermore,more » this drives temperatures inside the target to tens of millions of degrees and pressures to many billion times greater than Earth's atmosphere.« less

The US ICF Ignition Program and the Inertial Fusion Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lindl, J D; Hammel, B A; Logan, B G

2003-07-02

There has been rapid progress in inertial fusion in the past few years. This progress spans the construction of ignition facilities, a wide range of target concepts, and the pursuit of integrated programs to develop fusion energy using lasers, ion beams and z-pinches. Two ignition facilities are under construction (NIF in the U.S. and LMJ in France) and both projects are progressing toward an initial experimental capability. The LIL prototype beamline for LMJ and the first 4 beams of NIF will be available for experiments in 2003. The full 192 beam capability of NIF will be available in 2009 andmore » ignition experiments are expected to begin shortly after that time. There is steady progress in the target science and target fabrication in preparation for indirect drive ignition experiments on NIF. Advanced target designs may lead to 5-10 times more yield than initial target designs. There has also been excellent progress on the science of ion beam and z-pinch driven indirect drive targets. Excellent progress on direct-drive targets has been obtained on the Omega laser at the University of Rochester. This includes improved performance of targets with a pulse shape predicted to result in reduced hydrodynamic instability. Rochester has also obtained encouraging results from initial cryogenic implosions. There is widespread interest in the science of fast ignition because of its potential for achieving higher target gain with lower driver energy and relaxed target fabrication requirements. Researchers from Osaka have achieved outstanding implosion and heating results from the Gekko XII Petawatt facility and implosions suitable for fast ignition have been tested on the Omega laser. A broad based program to develop lasers and ions beams for IFE is under way with excellent progress in drivers, chambers, target fabrication and target injection. KrF and Diode Pumped Solid-State lasers (DPSSL) are being developed in conjunction with drywall chambers and direct drive targets. Induction accelerators for heavy ions are being developed in conjunction with thick-liquid protected wall chambers and indirect-drive targets.« less

X-ray source development for EXAFS measurements on the National Ignition Facility.

PubMed

Coppari, F; Thorn, D B; Kemp, G E; Craxton, R S; Garcia, E M; Ping, Y; Eggert, J H; Schneider, M B

2017-08-01

Extended X-ray absorption Fine Structure (EXAFS) measurements require a bright, spectrally smooth, and broad-band x-ray source. In a laser facility, such an x-ray source can be generated by a laser-driven capsule implosion. In order to optimize the x-ray emission, different capsule types and laser irradiations have been tested at the National Ignition Facility (NIF). A crystal spectrometer is used to disperse the x-rays and high efficiency image plate detectors are used to measure the absorption spectra in transmission geometry. EXAFS measurements at the K-edge of iron at ambient conditions have been obtained for the first time on the NIF laser, and the requirements for optimization have been established.

High-Speed RaPToRS

NASA Astrophysics Data System (ADS)

Henchen, Robert; Esham, Benjamin; Becker, William; Pogozelski, Edward; Padalino, Stephen; Sangster, Thomas; Glebov, Vladimir

2008-11-01

The High-Speed Rapid Pneumatic Transport of Radioactive Samples (HS-RaPToRS) system, designed to quickly and safely move radioactive materials, was assembled and tested at the Mercury facility of the Naval Research Laboratory (NRL) in Washington D.C. A sample, which is placed inside a four-inch-diameter carrier, is activated before being transported through a PVC tube via airflow. The carrier travels from the reaction chamber to the end station where it pneumatically brakes prior to the gate. A magnetic latch releases the gate when the carrier arrives and comes to rest. The airflow, optical carrier-monitoring devices, and end gate are controlled manually or automatically with LabView software. The installation and testing of the RaPToRS system at NRL was successfully completed with transport times of less than 3 seconds. The speed of the carrier averaged 16 m/s. Prospective facilities for similar systems include the Laboratory for Laser Energetics and the National Ignition Facility.

Experimental study on the minimum ignition temperature of coal dust clouds in oxy-fuel combustion atmospheres.

PubMed

Wu, Dejian; Norman, Frederik; Verplaetsen, Filip; Van den Bulck, Eric

2016-04-15

BAM furnace apparatus tests were conducted to investigate the minimum ignition temperature of coal dusts (MITC) in O2/CO2 atmospheres with an O2 mole fraction from 20 to 50%. Three coal dusts: Indonesian Sebuku coal, Pittsburgh No.8 coal and South African coal were tested. Experimental results showed that the dust explosion risk increases significantly with increasing O2 mole fraction by reducing the minimum ignition temperature for the three tested coal dust clouds dramatically (even by 100°C). Compared with conventional combustion, the inhibiting effect of CO2 was found to be comparatively large in dust clouds, particularly for the coal dusts with high volatile content. The retardation effect of the moisture content on the ignition of dust clouds was also found to be pronounced. In addition, a modified steady-state mathematical model based on heterogeneous reaction was proposed to interpret the observed experimental phenomena and to estimate the ignition mechanism of coal dust clouds under minimum ignition temperature conditions. The analysis revealed that heterogeneous ignition dominates the ignition mechanism for sub-/bituminous coal dusts under minimum ignition temperature conditions, but the decrease of coal maturity facilitates homogeneous ignition. These results improve our understanding of the ignition behaviour and the explosion risk of coal dust clouds in oxy-fuel combustion atmospheres. Copyright © 2015 Elsevier B.V. All rights reserved.

Scalable Sub-micron Patterning of Organic Materials Toward High Density Soft Electronics

PubMed Central

Kim, Jaekyun; Kim, Myung-Gil; Kim, Jaehyun; Jo, Sangho; Kang, Jingu; Jo, Jeong-Wan; Lee, Woobin; Hwang, Chahwan; Moon, Juhyuk; Yang, Lin; Kim, Yun-Hi; Noh, Yong-Young; Yun Jaung, Jae; Kim, Yong-Hoon; Kyu Park, Sung

2015-01-01

The success of silicon based high density integrated circuits ignited explosive expansion of microelectronics. Although the inorganic semiconductors have shown superior carrier mobilities for conventional high speed switching devices, the emergence of unconventional applications, such as flexible electronics, highly sensitive photosensors, large area sensor array, and tailored optoelectronics, brought intensive research on next generation electronic materials. The rationally designed multifunctional soft electronic materials, organic and carbon-based semiconductors, are demonstrated with low-cost solution process, exceptional mechanical stability, and on-demand optoelectronic properties. Unfortunately, the industrial implementation of the soft electronic materials has been hindered due to lack of scalable fine-patterning methods. In this report, we demonstrated facile general route for high throughput sub-micron patterning of soft materials, using spatially selective deep-ultraviolet irradiation. For organic and carbon-based materials, the highly energetic photons (e.g. deep-ultraviolet rays) enable direct photo-conversion from conducting/semiconducting to insulating state through molecular dissociation and disordering with spatial resolution down to a sub-μm-scale. The successful demonstration of organic semiconductor circuitry promise our result proliferate industrial adoption of soft materials for next generation electronics. PMID:26411932

Scalable sub-micron patterning of organic materials toward high density soft electronics

DOE PAGES

Kim, Jaekyun; Kim, Myung -Gil; Kim, Jaehyun; ...

2015-09-28

The success of silicon based high density integrated circuits ignited explosive expansion of microelectronics. Although the inorganic semiconductors have shown superior carrier mobilities for conventional high speed switching devices, the emergence of unconventional applications, such as flexible electronics, highly sensitive photosensors, large area sensor array, and tailored optoelectronics, brought intensive research on next generation electronic materials. The rationally designed multifunctional soft electronic materials, organic and carbon-based semiconductors, are demonstrated with low-cost solution process, exceptional mechanical stability, and on-demand optoelectronic properties. Unfortunately, the industrial implementation of the soft electronic materials has been hindered due to lack of scalable fine-patterning methods. Inmore » this report, we demonstrated facile general route for high throughput sub-micron patterning of soft materials, using spatially selective deep-ultraviolet irradiation. For organic and carbon-based materials, the highly energetic photons (e.g. deep-ultraviolet rays) enable direct photo-conversion from conducting/semiconducting to insulating state through molecular dissociation and disordering with spatial resolution down to a sub-μm-scale. As a result, the successful demonstration of organic semiconductor circuitry promise our result proliferate industrial adoption of soft materials for next generation electronics.« less

The impact of physicochemical property interactions of iso -octane/ethanol blends on ignition timescales

DOE PAGES

Barraza-Botet, Cesar L.; Luecke, Jon; Zigler, Bradley T.; ...

2018-03-20

This work presents new measurements of liquid fuel ignition delay times of iso-octane and ethanol fuel blends obtained from an ignition quality tester at the National Renewable Energy Laboratory (NREL IQT), which are compared to previous ignition delay data from the University of Michigan rapid compression facility (UM RCF), at the same experimental conditions. Pressure-time histories were used to determine liquid fuel ignition delays at global stoichiometric non-premixed conditions for iso-octane, ethanol and iso-octane/ethanol blends of 25, 50, 75% by volume in mixtures of 10% oxygen diluted in nitrogen. Temperatures ranging from 880 to 970 K were studied at amore » pressure of 10 atm. By comparing total ignition delay times from the NREL IQT with chemical ignition delay times from the UM RCF, the contributions of physical phenomena were quantified as representative time scales for spray injection, breakup and evaporation processes, and for gas-phase turbulent mixing. Regression analyses were developed for ignition time scales as function of blend level and charge temperature. Non-dimensional analyses were also carried out to determine the relative effects of physical time scales with respect to chemical ignition delay times.« less

The impact of physicochemical property interactions of iso -octane/ethanol blends on ignition timescales

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barraza-Botet, Cesar L.; Luecke, Jon; Zigler, Bradley T.

This work presents new measurements of liquid fuel ignition delay times of iso-octane and ethanol fuel blends obtained from an ignition quality tester at the National Renewable Energy Laboratory (NREL IQT), which are compared to previous ignition delay data from the University of Michigan rapid compression facility (UM RCF), at the same experimental conditions. Pressure-time histories were used to determine liquid fuel ignition delays at global stoichiometric non-premixed conditions for iso-octane, ethanol and iso-octane/ethanol blends of 25, 50, 75% by volume in mixtures of 10% oxygen diluted in nitrogen. Temperatures ranging from 880 to 970 K were studied at amore » pressure of 10 atm. By comparing total ignition delay times from the NREL IQT with chemical ignition delay times from the UM RCF, the contributions of physical phenomena were quantified as representative time scales for spray injection, breakup and evaporation processes, and for gas-phase turbulent mixing. Regression analyses were developed for ignition time scales as function of blend level and charge temperature. Non-dimensional analyses were also carried out to determine the relative effects of physical time scales with respect to chemical ignition delay times.« less

A sustained-arc ignition system for internal combustion engines

NASA Technical Reports Server (NTRS)

Birchenough, A. G.

1977-01-01

A sustained-arc ignition system was developed for internal combustion engines. It produces a very-long-duration ignition pulse with an energy in the order of 100 millijoules. The ignition pulse waveform can be controlled to predetermined actual ignition requirements. The design of the sustained-arc ignition system is presented in the report.

Mach-Zehnder Fiber-Optic Links for ICF Diagnostics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, E. K., Hermann, H. W.

2012-11-01

This article describes the operation and evolution of Mach-Zehnder links for single-point detectors in inertial confinement fusion experimental facilities, based on the Gamma Reaction History (GRH) diagnostic at the National Ignition Facility.

Thermite combustion enhancement resulting from biomodal luminum distribution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, K. M.; Pantoya, M.; Son, S. F.

2004-01-01

In recent years many studies that incorporated nano-scale or ultrafine aluminum (Al) as part of an energetic formulation and demonstrated significant performance enhancement. Decreasing the fuel particle size from the micron to nanometer range alters the material's chemical and thermal-physical properties. The result is increased particle reactivity that translates to an increase in the combustion wave speed and ignition sensitivity. Little is known, however, about the critical level of nano-sized fuel particles needed to enhance the performance of the energetic composite. Ignition sensitivity and combustion wave speed experiments were performed using a thermite composite of Al and MoO{sub 3} pressedmore » to a theoretical maximum density of 50% (2 g/cm{sup 3}). A bimodal Al particle size distribution was prepared using 4 or 20 {mu}m Al fuel particles that were replaced in 10% increments by 80 nm Al particles until the fuel was 100% 80 nm Al. These bimodal distributions allow the unique characteristics of nano-scale materials to be better understood. The pellets were ignited using a 50W CO{sub 2} laser. High speed imaging diagnostics were used to measure the ignition delay time and combustion wave speed.« less

Spectroscopic and chemical-kinetic analysis of the phases of HCCI autoignition and combustion for single- and two-stage ignition fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hwang, Wontae; Dec, John; Sjoeberg, Magnus

The temporal phases of autoignition and combustion in an HCCI engine have been investigated in both an all-metal engine and a matching optical engine. Gasoline, a primary reference fuel mixture (PRF80), and several representative real-fuel constituents were examined. Only PRF80, which is a two-stage ignition fuel, exhibited a ''cool-flame'' low-temperature heat-release (LTHR) phase. For all fuels, slow exothermic reactions occurring at intermediate temperatures raised the charge temperature to the hot-ignition point. In addition to the amount of LTHR, differences in this intermediate-temperature heat-release (ITHR) phase affect the fuel ignition quality. Chemiluminescence images of iso-octane show a weak and uniform lightmore » emission during this phase. This is followed by the main high-temperature heat-release (HTHR) phase. Finally, a ''burnout'' phase was observed, with very weak uniform emission and near-zero heat-release rate (HRR). To better understand these combustion phases, chemiluminescence spectroscopy and chemical-kinetic analysis were applied for the single-stage ignition fuel, iso-octane, and the two-stage fuel, PRF80. For both fuels, the spectrum obtained during the ITHR phase was dominated by formaldehyde chemiluminescence. This was similar to the LTHR spectrum of PRF80, but the emission intensity and the temperature were much higher, indicating differences between the ITHR and LTHR phases. Chemical-kinetic modeling clarified the differences and similarities between the LTHR and ITHR phases and the cause of the enhanced ITHR with PRF80. The HTHR spectra for both fuels were dominated by a broad CO continuum with some contribution from bands of HCO, CH, and OH. The modeling showed that the CO+ O{yields}CO{sub 2}+h{nu} reaction responsible for the CO continuum emission tracks the HTHR well, explaining the strong correlation observed experimentally between the total chemiluminescence and HRR during the HTHR phase. It also showed that the CO continuum does not contribute to the ITHR and LTHR chemiluminescence. Bands of H{sub 2}O and O{sub 2} in the red and IR regions were also detected during the HTHR, which the data indicated were most likely due to thermal excitation. The very weak light emission in the ''burnout'' phase also appeared to be thermal emission from H{sub 2}O and O{sub 2}. (author)« less

Nova Upgrade: A proposed ICF facility to demonstrate ignition and gain, revision 1

NASA Astrophysics Data System (ADS)

1992-07-01

The present objective of the national Inertial Confinement Fusion (ICF) Program is to determine the scientific feasibility of compressing and heating a small mass of mixed deuterium and tritium (DT) to conditions at which fusion occurs and significant energy is released. The potential applications of ICF will be determined by the resulting fusion energy yield (amount of energy produced) and gain (ratio of energy released to energy required to heat and compress the DT fuel). Important defense and civilian applications, including weapons physics, weapons effects simulation, and ultimately the generation of electric power will become possible if yields of 100 to 1,000 MJ and gains exceeding approximately 50 can be achieved. Once ignition and propagating bum producing modest gain (2 to 10) at moderate drive energy (1 to 2 MJ) has been achieved, the extension to high gain (greater than 50) is straightforward. Therefore, the demonstration of ignition and modest gain is the final step in establishing the scientific feasibility of ICF. Lawrence Livermore National Laboratory (LLNL) proposes the Nova Upgrade Facility to achieve this demonstration by the end of the decade. This facility would be constructed within the existing Nova building at LLNL for a total cost of approximately $400 M over the proposed FY 1995-1999 construction period. This report discusses this facility.

Laser ignition of an experimental combustion chamber with a multi-injector configuration at low pressure conditions

NASA Astrophysics Data System (ADS)

Börner, Michael; Manfletti, Chiara; Kroupa, Gerhard; Oschwald, Michael

2017-09-01

In search of reliable and light-weight ignition systems for re-ignitable upper stage engines, a laser ignition system was adapted and tested on an experimental combustion chamber for propellant injection into low combustion chamber pressures at 50-80 mbar. The injector head pattern consisted of five coaxial injector elements. Both, laser-ablation-driven ignition and laser-plasma-driven ignition were tested for the propellant combination liquid oxygen and gaseous hydrogen. The 122 test runs demonstrated the reliability of the ignition system for different ignition configurations and negligible degradation due to testing. For the laser-plasma-driven scheme, minimum laser pulse energies needed for 100% ignition probability were found to decrease when increasing the distance of the ignition location from the injector faceplate with a minimum of 2.6 mJ. For laser-ablation-driven ignition, the minimum pulse energy was found to be independent of the ablation material tested and was about 1.7 mJ. The ignition process was characterized using both high-speed Schlieren and OH* emission diagnostics. Based on these findings and on the increased fiber-based pulse transport capabilities recently published, new ignition system configurations for space propulsion systems relying on fiber-based pulse delivery are formulated. If the laser ignition system delivers enough pulse energy, the laser-plasma-driven configuration represents the more versatile configuration. If the laser ignition pulse power is limited, the application of laser-ablation-driven ignition is an option to realize ignition, but implies restrictions concerning the location of ignition.

Inertial Confinement Fusion and the National Ignition Facility (NIF)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ross, P.

2012-08-29

Inertial confinement fusion (ICF) seeks to provide sustainable fusion energy by compressing frozen deuterium and tritium fuel to extremely high densities. The advantages of fusion vs. fission are discussed, including total energy per reaction and energy per nucleon. The Lawson Criterion, defining the requirements for ignition, is derived and explained. Different confinement methods and their implications are discussed. The feasibility of creating a power plant using ICF is analyzed using realistic and feasible numbers. The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory is shown as a significant step forward toward making a fusion power plant based on ICF.more » NIF is the world’s largest laser, delivering 1.8 MJ of energy, with a peak power greater than 500 TW. NIF is actively striving toward the goal of fusion energy. Other uses for NIF are discussed.« less

14 CFR 33.37 - Ignition system.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Ignition system. 33.37 Section 33.37... STANDARDS: AIRCRAFT ENGINES Design and Construction; Reciprocating Aircraft Engines § 33.37 Ignition system. Each spark ignition engine must have a dual ignition system with at least two spark plugs for each...

Flow Effects on the Flammability Diagrams of Solid Fuels

NASA Technical Reports Server (NTRS)

Cordova, J. L.; Ceamanos, J.; Fernandez-Pello, A. C.; Long, R. T.; Torero, J. L.; Quintiere, J. G.

1997-01-01

A research program is currently underway with the final objective of developing a fundamental understanding of the controlling mechanisms underlying the flammability diagrams of solid combustible materials and their derived fire properties. Given that there is a high possibility of an accidental fire occurring in a space-based facility, understanding the fire properties of materials that will be used in such facilities is of critical importance. With this purpose, the flammability diagrams of the materials, as those produced by the Lateral Ignition and Flame Spread Test (LIFT) apparatus and by a new forced flow device, the Forced Flow Ignition and Flame Spread Test (FIST) apparatus, will be obtained. The specific objective of the program is to apply the new flammability apparatus, which will more accurately reflect the potential ambient conditions of space-based environments, to the characterization of the materials for space applications. This paper presents a parametric study of oxidizer flow effects on the ignition curve of the flammability diagrams of PMMA. The dependence of the ignition delay time on the external radiant flux and either the sample width (LIFT) or the flow velocity (FIST) has been studied. Although preliminary, the results indicate that natural and forced convection flow changes, affect the characteristics of the ignition curves of the flammability diagrams. The major effect on the ignition time appears to be due to convective transfer variations at the fuel surface. At high radiant fluxes or high flow velocities, however, it appears that gas phase processes become increasingly important, affecting the overall ignition delay time. A numerical analysis of the solid fuel heating and pyrolysis has also been developed. The theoretical predictions approximate the experiments well for conditions in which the gas phase induction time is negligible.

Test methods for determining the suitability of metal alloys for use in oxygen-enriched environments

NASA Technical Reports Server (NTRS)

Stoltzfus, Joel M.; Gunaji, Mohan V.

1991-01-01

Materials are more flammable in oxygen rich environments than in air. When the structural elements of a system containing oxygen ignite and burn, the results are often catastrophic, causing loss of equipment and perhaps even human lives. Therefore, selection of the proper metallic and non-metallic materials for use in oxygen systems is extremely important. While test methods for the selection of non-metallic materials have been available for years, test methods for the selection of alloys have not been available until recently. Presented here are several test methods that were developed recently at NASA's White Sands Test Facility (WSTF) to study the ignition and combustion of alloys, including the supersonic and subsonic speed particle impact tests, the frictional heating and coefficient of friction tests, and the promoted combustion test. These test methods are available for commercial use.

Cross section measurements in the 12C+12C system

NASA Astrophysics Data System (ADS)

Courtin, S.; Jiang, C. L.; Fruet, G.; Heine, M.; Jenkins, D. G.; Adsley, P.; Morris, L. G.; Regan, P. H.; Rudigier, M.; Montanari, D.; Della Negra, S.; de Séréville, N.; Haas, F.; Hammache, F.; Kirsebom, O. S.; Lesrel, J.; Meyer, A.; Montanari, D.; Auranen, K.; Avila, M. L.; Ayangeakaa, A. D.; Back, B. B.; Bottoni, S.; Carpenter, M.; Dickerson, C.; DiGiovine, B.; Greene, J. P.; Henderson, D. J.; Hoffman, C. R.; Janssens, R. V. F.; Kay, B. P.; Kuvin, S. A.; Lauritsen, T.; Pardo, R. C.; Rehm, K. E.; Santiago-Gonzalez, D.; Sethi, J.; Seweryniak, D.; Talwar, R.; Ugalde, C.; Zhu, S.; Deibel, C. M.; Marley, S. T.; Bourgin, D.; Stodel, C.; Lefebvre-Schuhl, A.; Almaraz-Calderon, S.; Fang, X.; Tang, X. D.; Alcorta, M.; Bucher, B.; Albers, M.; Bertone, P.

2018-01-01

The 12C+12C fusion reaction is one of the most important for nuclear astrophysics since it determines the carbon ignition in stellar environments. Two experiments which make use of the gamma-particle coincidence technique to measure the 12C+12C S-factors at deep sub barrier energies are discussed. Results are presented showing a decrease of the S-factor below Ec.m. = 3 MeV.

30 CFR 56.4430 - Storage facilities.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Storage facilities. 56.4430 Section 56.4430... Control Flammable and Combustible Liquids and Gases § 56.4430 Storage facilities. (a) Storage tanks for... changes. Vents for storage of Class I, II, or IIIA liquids shall be isolated or separated from ignition...

30 CFR 56.4430 - Storage facilities.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Storage facilities. 56.4430 Section 56.4430... Control Flammable and Combustible Liquids and Gases § 56.4430 Storage facilities. (a) Storage tanks for... changes. Vents for storage of Class I, II, or IIIA liquids shall be isolated or separated from ignition...

30 CFR 56.4430 - Storage facilities.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Storage facilities. 56.4430 Section 56.4430... Control Flammable and Combustible Liquids and Gases § 56.4430 Storage facilities. (a) Storage tanks for... changes. Vents for storage of Class I, II, or IIIA liquids shall be isolated or separated from ignition...

30 CFR 56.4430 - Storage facilities.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Storage facilities. 56.4430 Section 56.4430... Control Flammable and Combustible Liquids and Gases § 56.4430 Storage facilities. (a) Storage tanks for... changes. Vents for storage of Class I, II, or IIIA liquids shall be isolated or separated from ignition...

The use of tritium rich capsules with 25-35% deuterium to achieve ignition at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Wilson, D. C.; Spears, B. K.; Hatchett, S. P., Ii; Cerjan, C. J.; Springer, P. T.; Clark, D. S.; Edwards, M. J.; Salmonson, J. D.; Weber, S. V.; Hammel, B. A.; Grim, G. P.; Herrmann, H. W.; Wilke, M. D.

2010-08-01

Diagnostics such as neutron yield, ion temperature, image size and shape, and bang time in capsules with >~25 % deuterium fuel show changes due to burn product heating. The comparison of performance between a THD(2%) and THD(35%) can help predict ignition in a TD(50%) capsule. Surrogacy of THD capsules to TD(50%) is incomplete due to variations in fuel molecular vapour pressures. TD(25-35%) capsules might be preferred to study hot spot heating, but at the risk of increased fuel/ablator mixing.

Demonstration of Ignition Radiation Temperatures in Indirect-Drive Inertial Confinement Fusion Hohlraums

NASA Astrophysics Data System (ADS)

Glenzer, S. H.; MacGowan, B. J.; Meezan, N. B.; Adams, P. A.; Alfonso, J. B.; Alger, E. T.; Alherz, Z.; Alvarez, L. F.; Alvarez, S. S.; Amick, P. V.; Andersson, K. S.; Andrews, S. D.; Antonini, G. J.; Arnold, P. A.; Atkinson, D. P.; Auyang, L.; Azevedo, S. G.; Balaoing, B. N. M.; Baltz, J. A.; Barbosa, F.; Bardsley, G. W.; Barker, D. A.; Barnes, A. I.; Baron, A.; Beeler, R. G.; Beeman, B. V.; Belk, L. R.; Bell, J. C.; Bell, P. M.; Berger, R. L.; Bergonia, M. A.; Bernardez, L. J.; Berzins, L. V.; Bettenhausen, R. C.; Bezerides, L.; Bhandarkar, S. D.; Bishop, C. L.; Bond, E. J.; Bopp, D. R.; Borgman, J. A.; Bower, J. R.; Bowers, G. A.; Bowers, M. W.; Boyle, D. T.; Bradley, D. K.; Bragg, J. L.; Braucht, J.; Brinkerhoff, D. L.; Browning, D. F.; Brunton, G. K.; Burkhart, S. C.; Burns, S. R.; Burns, K. E.; Burr, B.; Burrows, L. M.; Butlin, R. K.; Cahayag, N. J.; Callahan, D. A.; Cardinale, P. S.; Carey, R. W.; Carlson, J. W.; Casey, A. D.; Castro, C.; Celeste, J. R.; Chakicherla, A. Y.; Chambers, F. W.; Chan, C.; Chandrasekaran, H.; Chang, C.; Chapman, R. F.; Charron, K.; Chen, Y.; Christensen, M. J.; Churby, A. J.; Clancy, T. J.; Cline, B. D.; Clowdus, L. C.; Cocherell, D. G.; Coffield, F. E.; Cohen, S. J.; Costa, R. L.; Cox, J. R.; Curnow, G. M.; Dailey, M. J.; Danforth, P. M.; Darbee, R.; Datte, P. S.; Davis, J. A.; Deis, G. A.; Demaret, R. D.; Dewald, E. L.; di Nicola, P.; di Nicola, J. M.; Divol, L.; Dixit, S.; Dobson, D. B.; Doppner, T.; Driscoll, J. D.; Dugorepec, J.; Duncan, J. J.; Dupuy, P. C.; Dzenitis, E. G.; Eckart, M. J.; Edson, S. L.; Edwards, G. J.; Edwards, M. J.; Edwards, O. D.; Edwards, P. W.; Ellefson, J. C.; Ellerbee, C. H.; Erbert, G. V.; Estes, C. M.; Fabyan, W. J.; Fallejo, R. N.; Fedorov, M.; Felker, B.; Fink, J. T.; Finney, M. D.; Finnie, L. F.; Fischer, M. J.; Fisher, J. M.; Fishler, B. T.; Florio, J. W.; Forsman, A.; Foxworthy, C. B.; Franks, R. M.; Frazier, T.; Frieder, G.; Fung, T.; Gawinski, G. N.; Gibson, C. R.; Giraldez, E.; Glenn, S. M.; Golick, B. P.; Gonzales, H.; Gonzales, S. A.; Gonzalez, M. J.; Griffin, K. L.; Grippen, J.; Gross, S. M.; Gschweng, P. H.; Gururangan, G.; Gu, K.; Haan, S. W.; Hahn, S. R.; Haid, B. J.; Hamblen, J. E.; Hammel, B. A.; Hamza, A. V.; Hardy, D. L.; Hart, D. R.; Hartley, R. G.; Haynam, C. A.; Heestand, G. M.; Hermann, M. R.; Hermes, G. L.; Hey, D. S.; Hibbard, R. L.; Hicks, D. G.; Hinkel, D. E.; Hipple, D. L.; Hitchcock, J. D.; Hodtwalker, D. L.; Holder, J. P.; Hollis, J. D.; Holtmeier, G. M.; Huber, S. R.; Huey, A. W.; Hulsey, D. N.; Hunter, S. L.; Huppler, T. R.; Hutton, M. S.; Izumi, N.; Jackson, J. L.; Jackson, M. A.; Jancaitis, K. S.; Jedlovec, D. R.; Johnson, B.; Johnson, M. C.; Johnson, T.; Johnston, M. P.; Jones, O. S.; Kalantar, D. H.; Kamperschroer, J. H.; Kauffman, R. L.; Keating, G. A.; Kegelmeyer, L. M.; Kenitzer, S. L.; Kimbrough, J. R.; King, K.; Kirkwood, R. K.; Klingmann, J. L.; Knittel, K. M.; Kohut, T. R.; Koka, K. G.; Kramer, S. W.; Krammen, J. E.; Krauter, K. G.; Krauter, G. W.; Krieger, E. K.; Kroll, J. J.; La Fortune, K. N.; Lagin, L. J.; Lakamsani, V. K.; Landen, O. L.; Lane, S. W.; Langdon, A. B.; Langer, S. H.; Lao, N.; Larson, D. W.; Latray, D.; Lau, G. T.; Le Pape, S.; Lechleiter, B. L.; Lee, Y.; Lee, T. L.; Li, J.; Liebman, J. A.; Lindl, J. D.; Locke, S. F.; Loey, H. K.; London, R. A.; Lopez, F. J.; Lord, D. M.; Lowe-Webb, R. R.; Lown, J. G.; Ludwigsen, A. P.; Lum, N. W.; Lyons, R. R.; Ma, T.; MacKinnon, A. J.; Magat, M. D.; Maloy, D. T.; Malsbury, T. N.; Markham, G.; Marquez, R. M.; Marsh, A. A.; Marshall, C. D.; Marshall, S. R.; Maslennikov, I. L.; Mathisen, D. G.; Mauger, G. J.; Mauvais, M.-Y.; McBride, J. A.; McCarville, T.; McCloud, J. B.; McGrew, A.; McHale, B.; Macphee, A. G.; Meeker, J. F.; Merill, J. S.; Mertens, E. P.; Michel, P. A.; Miller, M. G.; Mills, T.; Milovich, J. L.; Miramontes, R.; Montesanti, R. C.; Montoya, M. M.; Moody, J.; Moody, J. D.; Moreno, K. A.; Morris, J.; Morriston, K. M.; Nelson, J. R.; Neto, M.; Neumann, J. D.; Ng, E.; Ngo, Q. M.; Olejniczak, B. L.; Olson, R. E.; Orsi, N. L.; Owens, M. W.; Padilla, E. H.; Pannell, T. M.; Parham, T. G.; Patterson, R. W., Jr.; Pavel, G.; Prasad, R. R.; Pendlton, D.; Penko, F. A.; Pepmeier, B. L.; Petersen, D. E.; Phillips, T. W.; Pigg, D.; Piston, K. W.; Pletcher, K. D.; Powell, C. L.; Radousky, H. B.; Raimondi, B. S.; Ralph, J. E.; Rampke, R. L.; Reed, R. K.; Reid, W. A.; Rekow, V. V.; Reynolds, J. L.; Rhodes, J. J.; Richardson, M. J.; Rinnert, R. J.; Riordan, B. P.; Rivenes, A. S.; Rivera, A. T.; Roberts, C. J.; Robinson, J. A.; Robinson, R. B.; Robison, S. R.; Rodriguez, O. R.; Rogers, S. P.; Rosen, M. D.; Ross, G. F.; Runkel, M.; Runtal, A. S.; Sacks, R. A.; Sailors, S. F.; Salmon, J. T.; Salmonson, J. D.; Saunders, R. L.; Schaffer, J. R.; Schindler, T. M.; Schmitt, M. J.; Schneider, M. B.; Segraves, K. S.; Shaw, M. J.; Sheldrick, M. E.; Shelton, R. T.; Shiflett, M. K.; Shiromizu, S. J.; Shor, M.; Silva, L. L.; Silva, S. A.; Skulina, K. M.; Smauley, D. A.; Smith, B. E.; Smith, L. K.; Solomon, A. L.; Sommer, S.; Soto, J. G.; Spafford, N. I.; Speck, D. E.; Springer, P. T.; Stadermann, M.; Stanley, F.; Stone, T. G.; Stout, E. A.; Stratton, P. L.; Strausser, R. J.; Suter, L. J.; Sweet, W.; Swisher, M. F.; Tappero, J. D.; Tassano, J. B.; Taylor, J. S.; Tekle, E. A.; Thai, C.; Thomas, C. A.; Thomas, A.; Throop, A. L.; Tietbohl, G. L.; Tillman, J. M.; Town, R. P. J.; Townsend, S. L.; Tribbey, K. L.; Trummer, D.; Truong, J.; Vaher, J.; Valadez, M.; van Arsdall, P.; van Prooyen, A. J.; Vergel de Dios, E. O.; Vergino, M. D.; Vernon, S. P.; Vickers, J. L.; Villanueva, G. T.; Vitalich, M. A.; Vonhof, S. A.; Wade, F. E.; Wallace, R. J.; Warren, C. T.; Warrick, A. L.; Watkins, J.; Weaver, S.; Wegner, P. J.; Weingart, M. A.; Wen, J.; White, K. S.; Whitman, P. K.; Widmann, K.; Widmayer, C. C.; Wilhelmsen, K.; Williams, E. A.; Williams, W. H.; Willis, L.; Wilson, E. F.; Wilson, B. A.; Witte, M. C.; Work, K.; Yang, P. S.; Young, B. K.; Youngblood, K. P.; Zacharias, R. A.; Zaleski, T.; Zapata, P. G.; Zhang, H.; Zielinski, J. S.; Kline, J. L.; Kyrala, G. A.; Niemann, C.; Kilkenny, J. D.; Nikroo, A.; van Wonterghem, B. M.; Atherton, L. J.; Moses, E. I.

2011-02-01

We demonstrate the hohlraum radiation temperature and symmetry required for ignition-scale inertial confinement fusion capsule implosions. Cryogenic gas-filled hohlraums with 2.2 mm-diameter capsules are heated with unprecedented laser energies of 1.2 MJ delivered by 192 ultraviolet laser beams on the National Ignition Facility. Laser backscatter measurements show that these hohlraums absorb 87% to 91% of the incident laser power resulting in peak radiation temperatures of TRAD=300eV and a symmetric implosion to a 100μm diameter hot core.

Irradiated ignition of solid materials in reduced pressure atmosphere with various oxygen concentrations for fire safety in space habitats

NASA Astrophysics Data System (ADS)

Nakamura, Y.; Aoki, A.

Effects of sub-atmospheric ambient pressure and oxygen content on irradiated ignition characteristics of solid combustibles were examined experimentally in order to elucidate the flammability and chance of fire in depressurized systems and give ideas for the fire safety and fire fighting strategies for such environments. Thin cellulosic paper was used as the solid combustible since cellulose is one of major organic compounds and flammables in the nature. Applied atmospheres consisted of inert gases (either CO 2 or N 2) and oxygen at various mixture ratios. Total ambient pressure ( P) was varied from 101 kPa (standard atmospheric pressure, P0) to 20 kPa. Ignition was initiated by external thermal radiation with CO 2 laser (10 W total; 21.3 W/cm 2 of the corresponding peak flux) onto the solid surface. Thermal degradation of the solid produced combustible gaseous products (e.g. CO, H 2, or other low weight of HCs) and these products mixed with ambient oxygen to form the combustible mixture over the solid. Heat transfer from the irradiated surface into the mixture accelerated the exothermic reaction in the gas phase and finally thermal runaway (ignition) was achieved. A digital video camera was used to analyze the ignition characteristics. Flammability maps in partial pressure of oxygen (ppO 2) and normalized ambient pressure ( P/ P0) plane were made to reveal the fire hazard in depressurized environments. Results showed that a wider flammable range was obtained in sub-atmospherics conditions. In middle pressure range (101-40 kPa), the required ppO 2 for ignition decreased almost linearly as the total pressure decreased, indicating that higher fire risk is expected. In lower pressure range (<40 kPa), the required partial pressure of oxygen increased dramatically, then ignition was eventually not achieved at pressures less than 20 kPa under the conditions studied here. The findings suggest that it might be difficult to satisfy safety in space agriculture since it has been reported that higher oxygen concentrations are preferable for plant growth in depressurized environments. Our results imply that there is an optimum pressure level to achieve less fire chance with acceptable plant growth. An increase of the flammable range in middle pressure level might be explained by following two effects: one is a physical effect, such as a weak convective thermal removal from ignitable domain (near the hot surface) to the ambient of atmosphere, and the other is chemical effect which causes so-called "explosion peninsula" as a result of depleting radical consumption due to third-body recombination reaction. Further studies are necessary to determine the controlling factor on the observed flammable trend in depressurized conditions.

Implementation of the next-generation Gas Cherenkov Detector at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Carrera, J. A.; Herrmann, H. W.; Khater, H. Y.; Carpenter, A. C.; Beeman, B. V.; Hernandez, J. E.; Sitaraman, S.; Lopez, F. E.; Zylstra, A. B.; Griego, J. R.; Kim, Y. H.; Gales, S. A.; Horsfield, C. J.; Milnes, J. S.; Hares, J. D.

2017-08-01

The newest Gas Cherenkov Detector (GCD-3) diagnostic has completed its Phase I commissioning/milestone at the National Ignition Facility (NIF). GCD-3 was fielded for several years at the Omega Laser Facility in its initial configuration, before being moved to the NIF. Installation at the NIF involved optimization of GCD-3 for the higher background environment and designing a new insertion carrier assembly. GCD-3 serves as the initial phase towards the implementation of the "Super GCD" (SGCD) at the NIF. During this phase of development GCD-3 took measurements from a re-entrant well, 3.9 meters from target chamber center (TCC). Plans to insert GCD-3 within 20 cm of TCC with a Target and Diagnostic Manipulator (TANDM) will be discussed. Data was collected using a Photomultiplier Tube (PMT) in combination with a Mach-Zehnder based recording system. These measurements were used to aid in shielding analysis, validate MCNP models, and fuel design efforts for the SGCD. Findings from the initial data will be covered extensively, including an in-depth look into sources of background and possible mitigation strategies. Ongoing development of phase two, the addition of an ultra-high bandwidth Pulse Dilatation Photomultiplier Tube (PD-PMT), will also be presented.

Simulated performance of the optical Thomson scattering diagnostic designed for the National Ignition Facility

DOE PAGES

Ross, J. S.; Datte, P.; Divol, L.; ...

2016-07-28

An optical Thomson scattering diagnostic has been designed for the National Ignition Facility to characterize under-dense plasmas. Here, we report on the design of the system and the expected performance for different target configurations. The diagnostic is designed to spatially and temporally resolve the Thomson scattered light from laser driven targets. The diagnostic will collect scattered light from a 50 × 50 × 200 μm volume. The optical design allows operation with different probe laser wavelengths. A deep-UV probe beam (λ 0 = 210 nm) will be used to Thomson scatter from electron plasma densities of ~5 × 10 20more » cm -3 while a 3ω probe will be used for plasma densities of ~1 × 10 19 cm -3. The diagnostic package contains two spectrometers: the first to resolve Thomson scattering from ion acoustic wave fluctuations and the second to resolve scattering from electron plasma wave fluctuations. Expected signal levels relative to background will be presented for typical target configurations (hohlraums and a planar foil).« less

Optical smoothing of laser imprinting in planar-target experiments on OMEGA EP using multi-FM 1-D smoothing by spectral dispersion

DOE PAGES

Hohenberger, M.; Shvydky, A.; Marozas, J. A.; ...

2016-09-07

Direct-drive ignition on the National Ignition Facility (NIF) requires single-beam smoothing to minimize imprinting of laser nonuniformities that can negatively affect implosion performance. One-dimensional, multi-FM smoothing by spectral dispersion (SSD) has been proposed to provide the required smoothing [J. A. Marozas, J. D. Zuegel, and T. J. B. Collins, Bull. Am. Phys. Soc. 55, 294 (2010)]. A prototype multi-FM SSD system has been integrated into the NIF-like beamline of the OMEGA EP Laser System. Experiments have been performed to verify the smoothing performance by measuring Rayleigh–Taylor growth rates in planar targets of laser-imprinted and preimposed surface modulations. Multi-FM 1-D SSDmore » has been observed to reduce imprint levels by ~50% compared to the nominal OMEGA EP SSD system. In conclusion, the experimental results are in agreement with 2-D DRACO simulations using realistic, time-dependent far-field spot-intensity calculations that emulate the effect of SSD.« less

Optical smoothing of laser imprinting in planar-target experiments on OMEGA EP using multi-FM 1-D smoothing by spectral dispersion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hohenberger, M., E-mail: mhoh@lle.rochester.edu; Shvydky, A.; Marozas, J. A.

Direct-drive ignition on the National Ignition Facility (NIF) requires single-beam smoothing to minimize imprinting of laser nonuniformities that can negatively affect implosion performance. One-dimensional, multi-FM smoothing by spectral dispersion (SSD) has been proposed to provide the required smoothing [Marozas et al., Bull. Am. Phys. Soc. 55, 294 (2010)]. A prototype multi-FM SSD system has been integrated into the NIF-like beamline of the OMEGA EP Laser System. Experiments have been performed to verify the smoothing performance by measuring Rayleigh–Taylor growth rates in planar targets of laser-imprinted and preimposed surface modulations. Multi-FM 1-D SSD has been observed to reduce imprint levels bymore » ∼50% compared to the nominal OMEGA EP SSD system. The experimental results are in agreement with 2-D DRACO simulations using realistic, time-dependent far-field spot-intensity calculations that emulate the effect of SSD.« less

Optical smoothing of laser imprinting in planar-target experiments on OMEGA EP using multi-FM 1-D smoothing by spectral dispersion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hohenberger, M.; Shvydky, A.; Marozas, J. A.

Direct-drive ignition on the National Ignition Facility (NIF) requires single-beam smoothing to minimize imprinting of laser nonuniformities that can negatively affect implosion performance. One-dimensional, multi-FM smoothing by spectral dispersion (SSD) has been proposed to provide the required smoothing [J. A. Marozas, J. D. Zuegel, and T. J. B. Collins, Bull. Am. Phys. Soc. 55, 294 (2010)]. A prototype multi-FM SSD system has been integrated into the NIF-like beamline of the OMEGA EP Laser System. Experiments have been performed to verify the smoothing performance by measuring Rayleigh–Taylor growth rates in planar targets of laser-imprinted and preimposed surface modulations. Multi-FM 1-D SSDmore » has been observed to reduce imprint levels by ~50% compared to the nominal OMEGA EP SSD system. In conclusion, the experimental results are in agreement with 2-D DRACO simulations using realistic, time-dependent far-field spot-intensity calculations that emulate the effect of SSD.« less

Reaction path in the formation of titanium diboride by a magnesium thermite process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sundaram, V.; Logan, K.V.; Speyer, R.F.

1995-12-31

TiB{sub 2} was formed by a thermite reaction amongst Mg, amorphous B{sub 2}O{sub 3} and TiO{sub 2} powders. Mixtures consisting of 2Mg-TiO{sub 2}, 3Mg-B{sub 2}O{sub 3} and 5Mg-TiO{sub 2}-B{sub 2}O{sub 3} were heat treated using DTA and separately via ignition with a nichrome wire; product phases were identified using XRD. MgO and Ti were products from the first mixture reacted in argon, whereas an incomplete transformation forming Mg{sub 3}TiO{sub 4} occurred in air. For the second mixture, a reaction forming Mg{sub 3}B{sub 2}O{sup 6} occurred in air, but no reaction occurred in argon due to deficiency of oxygen. Minor amountsmore » Of Mg{sub 3}B{sub 2}O{sub 6} and Mg{sub 2}TiO{sub 4} were detected in addition to the predicted product phases of MgO and TiB{sub 2} for the third mixture ignited both in air and argon. Based on available evidence, a path for this reaction was deduced; Mg particles in contact with TiO{sub 2} reacted to form Ti, which in turn reacted with B{sub 2}O{sub 3} to form TiB{sub 2}. TiB{sub 2} product particles from the reaction in argon had a more faceted appearance than those formed during the reaction in air. This was interpreted to be the result of glassy B{sub 2}O{sub 3} surface layer formation on TiB{sub 2} particles in air.« less

National direct-drive program on OMEGA and the National Ignition Facility

NASA Astrophysics Data System (ADS)

Goncharov, V. N.; Regan, S. P.; Campbell, E. M.; Sangster, T. C.; Radha, P. B.; Myatt, J. F.; Froula, D. H.; Betti, R.; Boehly, T. R.; Delettrez, J. A.; Edgell, D. H.; Epstein, R.; Forrest, C. J.; Glebov, V. Yu; Harding, D. R.; Hu, S. X.; Igumenshchev, I. V.; Marshall, F. J.; McCrory, R. L.; Michel, D. T.; Seka, W.; Shvydky, A.; Stoeckl, C.; Theobald, W.; Gatu-Johnson, M.

2017-01-01

A major advantage of the laser direct-drive (DD) approach to ignition is the increased fraction of laser drive energy coupled to the hot spot and relaxed hot-spot requirements for the peak pressure and convergence ratios relative to the indirect-drive approach at equivalent laser energy. With the goal of a successful ignition demonstration using DD, the recently established national strategy has several elements and involves multiple national and international institutions. These elements include the experimental demonstration on OMEGA cryogenic implosions of hot-spot conditions relevant for ignition at MJ-scale energies available at the National Ignition Facility (NIF) and developing an understanding of laser-plasma interactions and laser coupling using DD experiments on the NIF. DD designs require reaching central stagnation pressures in excess of 100 Gbar. The current experiments on OMEGA have achieved inferred peak pressures of 56 Gbar (Regan et al 2016 Phys. Rev. Lett. 117 025001). Extensive analysis of the cryogenic target experiments and two- and three-dimensional simulations suggest that power balance, target offset, and target quality are the main limiting factors in target performance. In addition, cross-beam energy transfer (CBET) has been identified as the main mechanism reducing laser coupling. Reaching the goal of demonstrating hydrodynamic equivalence on OMEGA includes improving laser power balance, target position, and target quality at shot time. CBET must also be significantly reduced and several strategies have been identified to address this issue.

Time-resolved measurements of the hot-electron population in ignition-scale experiments on the National Ignition Facility (invited)

NASA Astrophysics Data System (ADS)

Hohenberger, M.; Albert, F.; Palmer, N. E.; Lee, J. J.; Döppner, T.; Divol, L.; Dewald, E. L.; Bachmann, B.; MacPhee, A. G.; LaCaille, G.; Bradley, D. K.; Stoeckl, C.

2014-11-01

In laser-driven inertial confinement fusion, hot electrons can preheat the fuel and prevent fusion-pellet compression to ignition conditions. Measuring the hot-electron population is key to designing an optimized ignition platform. The hot electrons in these high-intensity, laser-driven experiments, created via laser-plasma interactions, can be inferred from the bremsstrahlung generated by hot electrons interacting with the target. At the National Ignition Facility (NIF) [G. H. Miller, E. I. Moses, and C. R. Wuest, Opt. Eng. 43, 2841 (2004)], the filter-fluorescer x-ray (FFLEX) diagnostic-a multichannel, hard x-ray spectrometer operating in the 20-500 keV range-has been upgraded to provide fully time-resolved, absolute measurements of the bremsstrahlung spectrum with ˜300 ps resolution. Initial time-resolved data exhibited significant background and low signal-to-noise ratio, leading to a redesign of the FFLEX housing and enhanced shielding around the detector. The FFLEX x-ray sensitivity was characterized with an absolutely calibrated, energy-dispersive high-purity germanium detector using the high-energy x-ray source at NSTec Livermore Operations over a range of K-shell fluorescence energies up to 111 keV (U Kβ). The detectors impulse response function was measured in situ on NIF short-pulse (˜90 ps) experiments, and in off-line tests.

Planar Laser-Plasma Interaction Experiments at Direct-Drive Ignition-Relevant Scale Lengths at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Rosenberg, M. J.; Solodov, A. A.; Seka, W.; Myatt, J. F.; Regan, S. P.; Hohenberger, M.; Epstein, R.; Froula, D. H.; Radha, P. B.; Michel, P. A.; Moody, J. D.; Masse, L.; Goyon, C.; Turnbull, D. P.; Barrios, M. A.; Bates, J. W.; Schmitt, A. J.

2016-10-01

The first experiments at the National Ignition Facility to probe laser-plasma interactions and the hot electron production at scale lengths relevant to direct-drive ignition are reported. The irradiation on one side of planar CH foils generated a plasma at the quarter-critical surface with predicted density scale lengths of Ln 600 μm, measured electron temperatures of Te 3.5 to 4.0 keV, and overlapped laser intensities of I 6 to 15 ×1014W/cm2. Optical emission from stimulated Raman scattering (SRS) and at ω/2 are correlated with the time-dependent hard x-ray signal. The fraction of laser energy converted to hot electrons increased from 0.5 % to 2.3 % as the laser intensity increased from 6 to 15 ×1014W/cm2, while the hot electron temperature was nearly constant around 40 to 50 keV. Only a sharp red-shifted feature is observed around ω/2, and both refracted and sidescattered SRS are detected, suggesting that multibeam SRS contributes to, and may even dominate, hot-electron production. These results imply a diminished presence of two-plasmon decay relative to SRS at these conditions, which has implications for hot-electron preheat mitigation strategies for direct-drive ignition. This work is supported by the DOE NNSA under Award Number DE-NA0001944.

Planar Two-Plasmon-Decay Experiments at Polar-Direct-Drive Ignition-Relevant Scale Lengths at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Rosenberg, M. J.; Solodov, A. A.; Seka, W.; Myatt, J. F.; Regan, S. P.; Hohenberger, M.; Epstein, R.; Collins, T. J. B.; Turnbull, D. P.; Ralph, J. E.; Barrios, M. A.; Moody, J. D.

2015-11-01

Results from the first experiments at the National Ignition Facility (NIF) to probe two-plasmon -decay (TPD) hot-electron production at scale lengths relevant to polar-direct-drive (PDD) ignition are reported. The irradiation on one side of a planar CH foil generated a plasma at the quarter-critical surface with a predicted density gradient scale length of Ln ~ 600 μm , a measured electron temperature of Te ~ 3 . 5 to 4.0 keV, an overlapped laser intensity of I ~ 6 ×1014 W/cm2, and a predicted TPD threshold parameter of η ~ 4 . The hard x-ray spectrum and the Kα emission from a buried Mo layer were measured to infer the hot-electron temperature and the fraction of total laser energy converted to TPD hot electrons. Optical emission at ω/2 correlated with the time-dependent hard x-ray signal confirms that TPD is responsible for the hot-electron generation. The effect of laser beam angle of incidence on TPD hot-electron generation was assessed, and the data show that the beam angle of incidence did not have a strong effect. These results will be used to benchmark simulations of TPD hot-electron production at conditions relevant to PDD ignition-scale implosions. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

An in-flight radiography platform to measure hydrodynamic instability growth in inertial confinement fusion capsules at the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raman, K. S.; Smalyuk, V. A.; Casey, D. T.

2014-07-15

A new in-flight radiography platform has been established at the National Ignition Facility (NIF) to measure Rayleigh–Taylor and Richtmyer–Meshkov instability growth in inertial confinement fusion capsules. The platform has been tested up to a convergence ratio of 4. An experimental campaign is underway to measure the growth of pre-imposed sinusoidal modulations of the capsule surface, as a function of wavelength, for a pair of ignition-relevant laser drives: a “low-foot” drive representative of what was fielded during the National Ignition Campaign (NIC) [Edwards et al., Phys. Plasmas 20, 070501 (2013)] and the new high-foot [Dittrich et al., Phys. Rev. Lett. 112,more » 055002 (2014); Park et al., Phys. Rev. Lett. 112, 055001 (2014)] pulse shape, for which the predicted instability growth is much lower. We present measurements of Legendre modes 30, 60, and 90 for the NIC-type, low-foot, drive, and modes 60 and 90 for the high-foot drive. The measured growth is consistent with model predictions, including much less growth for the high-foot drive, demonstrating the instability mitigation aspect of this new pulse shape. We present the design of the platform in detail and discuss the implications of the data it generates for the on-going ignition effort at NIF.« less

X-ray source development for EXAFS measurements on the National Ignition Facility

DOE PAGES

Coppari, F.; Thorn, D. B.; Kemp, G. E.; ...

2017-08-28

We present that extended X-ray absorption Fine Structure (EXAFS) measurements require a bright, spectrally smooth, and broad-band x-ray source. In a laser facility, such an x-ray source can be generated by a laser-driven capsule implosion. In order to optimize the x-ray emission, different capsule types and laser irradiations have been tested at the National Ignition Facility (NIF). A crystal spectrometer is used to disperse the x-rays and high efficiency image plate detectors are used to measure the absorption spectra in transmission geometry. Finally, EXAFS measurements at the K-edge of iron at ambient conditions have been obtained for the first timemore » on the NIF laser, and the requirements for optimization have been established.« less

Wavelength Detuning Cross-Beam Energy Transfer Mitigation Scheme for Direct-Drive: Modeling and Evidence from National Ignition Facility Implosions

NASA Astrophysics Data System (ADS)

Marozas, J. A.

2017-10-01

Cross-beam energy transfer (CBET) has been shown to significantly reduce the laser absorption and implosion speed in direct-drive implosion experiments on OMEGA and the National Ignition Facility (NIF). Mitigating CBET assists in achieving ignition-relevant hot-spot pressures in deuterium-tritium cryogenic OMEGA implosions. In addition, reducing CBET permits lower, more hydrodynamically stable, in-flight aspect ratio ignition designs with smaller nonuniformity growth during the acceleration phase. Detuning the wavelengths of the crossing beams is one of several techniques under investigation at the University of Rochester to mitigate CBET. This talk will describe these techniques with an emphasis on wavelength detuning. Recent experiments designed and predicted using multidimensional hydrodynamic simulations including CBET on the NIF have exploited the wavelength arrangement of the NIF beam geometry to demonstrate CBET mitigation through wavelength detuning in polar-direct-drive (PDD) implosions. Shapes and trajectories inferred from time-resolved x-ray radiography of the imploding shell, scattered-light spectra, and hard x-ray spectra generated by suprathermal electrons all indicate a reduction in CBET. These results and their implications for direct-drive ignition will be presented and discussed. In addition, hydrodynamically scaled ignition-relevant designs for OMEGA implosions exploiting wavelength detuning will be presented. Changes required to the OMEGA laser to permit wavelength detuning will be discussed. Future plans for PDD on the NIF including more-uniform implosions with CBET mitigation will be explored. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

Ignition of steel alloys by impact of low-velocity iron/inert particles in gaseous oxygen

NASA Technical Reports Server (NTRS)

Benz, Frank J.; Mcilroy, Kenneth; Williams, Ralph E.

1988-01-01

The ignition of carbon steel and 316 and 304 stainless steels caused by the impact of low-velocity particles (a standard mixture consisting of 2 g of iron and 3 g of inert materials) in gaseous oxygen was investigated using NASA/White Sands Test Facility for the ignition test, and a subsonic particle impact chamber to accelerate the particles that were injected into flowing oxygen upstream of the target specimen. It was found that the oxygen velocities required to ignite the three alloys were the same as that required to ignite the particle mixture. Ignition occurred at oxygen velocities greater than 45 m/sec at 20 to 24 MPa and was found to be independent of pressure between 2 and 30 MPa. Comparison of the present results and the past results from Wegener (1964) with the Compressed Gas Association (CGA) oxygen velocity limits for safe operations indicates that the CGA limits may be excessively conservative at high pressures and too liberal at low pressures.

Passive, Low Cost Neutron Detectors for Neutron Diagnostics at the National Ignition Facility

DTIC Science & Technology

2013-03-01

Facility PTFE Polytetrafluoroethylene TLD Thermoluminescent Dosimeter α Conversion Coefficient (Conversion...because they required a large investment in automated track counting equipment. Thermoluminescent dosimeters ( TLDs ) remained as a viable option. They...necessary to predict radiation damage to measurement electronics . Due to programmatic and facility limitations, traditional neutron measurement

Dual coil ignition system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huberts, Garlan J.; Qu, Qiuping; Czekala, Michael Damian

2017-03-28

A dual coil ignition system is provided. The dual coil ignition system includes a first inductive ignition coil including a first primary winding and a first secondary winding, and a second inductive ignition coil including a second primary winding and a second secondary winding, the second secondary winding connected in series to the first secondary winding. The dual coil ignition system further includes a diode network including a first diode and a second diode connected between the first secondary winding and the second secondary winding.

Automated analysis of hot spot X-ray images at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Khan, S. F.; Izumi, N.; Glenn, S.; Tommasini, R.; Benedetti, L. R.; Ma, T.; Pak, A.; Kyrala, G. A.; Springer, P.; Bradley, D. K.; Town, R. P. J.

2016-11-01

At the National Ignition Facility, the symmetry of the hot spot of imploding capsules is diagnosed by imaging the emitted x-rays using gated cameras and image plates. The symmetry of an implosion is an important factor in the yield generated from the resulting fusion process. The x-ray images are analyzed by decomposing the image intensity contours into Fourier and Legendre modes. This paper focuses on the additional protocols for the time-integrated shape analysis from image plates. For implosions with temperatures above ˜4 keV, the hard x-ray background can be utilized to infer the temperature of the hot spot.

Observation of a reflected shock in an indirectly driven spherical implosion at the national ignition facility.

PubMed

Le Pape, S; Divol, L; Berzak Hopkins, L; Mackinnon, A; Meezan, N B; Casey, D; Frenje, J; Herrmann, H; McNaney, J; Ma, T; Widmann, K; Pak, A; Grimm, G; Knauer, J; Petrasso, R; Zylstra, A; Rinderknecht, H; Rosenberg, M; Gatu-Johnson, M; Kilkenny, J D

2014-06-06

A 200  μm radius hot spot at more than 2 keV temperature, 1  g/cm^{3} density has been achieved on the National Ignition Facility using a near vacuum hohlraum. The implosion exhibits ideal one-dimensional behavior and 99% laser-to-hohlraum coupling. The low opacity of the remaining shell at bang time allows for a measurement of the x-ray emission of the reflected central shock in a deuterium plasma. Comparison with 1D hydrodynamic simulations puts constraints on electron-ion collisions and heat conduction. Results are consistent with classical (Spitzer-Harm) heat flux.

High-resolution measurements of the DT neutron spectrum using new CD foils in the Magnetic Recoil neutron Spectrometer (MRS) on the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gatu Johnson, M., E-mail: gatu@psfc.mit.edu; Frenje, J. A.; Li, C. K.

2016-11-15

The Magnetic Recoil neutron Spectrometer (MRS) on the National Ignition Facility measures the DT neutron spectrum from cryogenically layered inertial confinement fusion implosions. Yield, areal density, apparent ion temperature, and directional fluid flow are inferred from the MRS data. This paper describes recent advances in MRS measurements of the primary peak using new, thinner, reduced-area deuterated plastic (CD) conversion foils. The new foils allow operation of MRS at yields 2 orders of magnitude higher than previously possible, at a resolution down to ∼200 keV FWHM.

Variable convergence liquid layer implosions on the National Ignition Facility

NASA Astrophysics Data System (ADS)

Zylstra, A. B.; Yi, S. A.; Haines, B. M.; Olson, R. E.; Leeper, R. J.; Braun, T.; Biener, J.; Kline, J. L.; Batha, S. H.; Berzak Hopkins, L.; Bhandarkar, S.; Bradley, P. A.; Crippen, J.; Farrell, M.; Fittinghoff, D.; Herrmann, H. W.; Huang, H.; Khan, S.; Kong, C.; Kozioziemski, B. J.; Kyrala, G. A.; Ma, T.; Meezan, N. B.; Merrill, F.; Nikroo, A.; Peterson, R. R.; Rice, N.; Sater, J. D.; Shah, R. C.; Stadermann, M.; Volegov, P.; Walters, C.; Wilson, D. C.

2018-05-01

Liquid layer implosions using the "wetted foam" technique, where the liquid fuel is wicked into a supporting foam, have been recently conducted on the National Ignition Facility for the first time [Olson et al., Phys. Rev. Lett. 117, 245001 (2016)]. We report on a series of wetted foam implosions where the convergence ratio was varied between 12 and 20. Reduced nuclear performance is observed as convergence ratio increases. 2-D radiation-hydrodynamics simulations accurately capture the performance at convergence ratios (CR) ˜ 12, but we observe a significant discrepancy at CR ˜ 20. This may be due to suppressed hot-spot formation or an anomalous energy loss mechanism.

Laser-direct-drive program: Promise, challenge, and path forward

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, E. M.; Goncharov, V. N.; Sangster, T. C.

Along with laser-indirect (x-ray)-drive and magnetic-drive target concepts, laser direct drive is a viable approach to achieving ignition and gain with inertial confinement fusion. In the United States, a national program has been established to demonstrate and understand the physics of laser direct drive. The program utilizes the Omega Laser Facility to conduct implosion and coupling physics at the nominally 30-kJ scale and laser–plasma interaction and coupling physics at the MJ scale at the National Ignition Facility. This paper will discuss the motivation and challenges for laser direct drive and the broad-based program presently underway in the United States.

Automated analysis of hot spot X-ray images at the National Ignition Facility

DOE PAGES

Khan, S. F.; Izumi, N.; Glenn, S.; ...

2016-09-02

At the National Ignition Facility, the symmetry of the hot spot of imploding capsules is diagnosed by imaging the emitted x-rays using gated cameras and image plates. The symmetry of an implosion is an important factor in the yield generated from the resulting fusion process. The x-ray images are analyzed by decomposing the image intensity contours into Fourier and Legendre modes. This paper focuses on the additional protocols for the time-integrated shape analysis from image plates. Here, for implosions with temperatures above ~4keV, the hard x-ray background can be utilized to infer the temperature of the hot spot.

High-resolution measurements of the DT neutron spectrum using new CD foils in the Magnetic Recoil neutron Spectrometer (MRS) on the National Ignition Facility

DOE PAGES

Gatu Johnson, M.; Frenje, J. A.; Bionta, R. M.; ...

2016-08-09

The Magnetic Recoil neutron Spectrometer (MRS) on the National Ignition Facility measures the DT neutron spectrum from cryogenically layered inertial confinement fusion implosions. Yield, areal density, apparent ion temperature, and directional fluid flow are inferred from the MRS data. Here, this paper describes recent advances in MRS measurements of the primary peak using new, thinner, reduced-area deuterated plastic (CD) conversion foils. The new foils allow operation of MRS at yields 2 orders of magnitude higher than previously possible, at a resolution down to ~200 keV FWHM.

Laser-direct-drive program: Promise, challenge, and path forward

DOE PAGES

Campbell, E. M.; Goncharov, V. N.; Sangster, T. C.; ...

2017-03-19

Along with laser-indirect (x-ray)-drive and magnetic-drive target concepts, laser direct drive is a viable approach to achieving ignition and gain with inertial confinement fusion. In the United States, a national program has been established to demonstrate and understand the physics of laser direct drive. The program utilizes the Omega Laser Facility to conduct implosion and coupling physics at the nominally 30-kJ scale and laser–plasma interaction and coupling physics at the MJ scale at the National Ignition Facility. This paper will discuss the motivation and challenges for laser direct drive and the broad-based program presently underway in the United States.

Automated analysis of hot spot X-ray images at the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khan, S. F., E-mail: khan9@llnl.gov; Izumi, N.; Glenn, S.

At the National Ignition Facility, the symmetry of the hot spot of imploding capsules is diagnosed by imaging the emitted x-rays using gated cameras and image plates. The symmetry of an implosion is an important factor in the yield generated from the resulting fusion process. The x-ray images are analyzed by decomposing the image intensity contours into Fourier and Legendre modes. This paper focuses on the additional protocols for the time-integrated shape analysis from image plates. For implosions with temperatures above ∼4 keV, the hard x-ray background can be utilized to infer the temperature of the hot spot.

High-resolution measurements of the DT neutron spectrum using new CD foils in the Magnetic Recoil neutron Spectrometer (MRS) on the National Ignition Facility.

PubMed

Gatu Johnson, M; Frenje, J A; Bionta, R M; Casey, D T; Eckart, M J; Farrell, M P; Grim, G P; Hartouni, E P; Hatarik, R; Hoppe, M; Kilkenny, J D; Li, C K; Petrasso, R D; Reynolds, H G; Sayre, D B; Schoff, M E; Séguin, F H; Skulina, K; Yeamans, C B

2016-11-01

The Magnetic Recoil neutron Spectrometer (MRS) on the National Ignition Facility measures the DT neutron spectrum from cryogenically layered inertial confinement fusion implosions. Yield, areal density, apparent ion temperature, and directional fluid flow are inferred from the MRS data. This paper describes recent advances in MRS measurements of the primary peak using new, thinner, reduced-area deuterated plastic (CD) conversion foils. The new foils allow operation of MRS at yields 2 orders of magnitude higher than previously possible, at a resolution down to ∼200 keV FWHM.

Automated analysis of hot spot X-ray images at the National Ignition Facility.

PubMed

Khan, S F; Izumi, N; Glenn, S; Tommasini, R; Benedetti, L R; Ma, T; Pak, A; Kyrala, G A; Springer, P; Bradley, D K; Town, R P J

2016-11-01

At the National Ignition Facility, the symmetry of the hot spot of imploding capsules is diagnosed by imaging the emitted x-rays using gated cameras and image plates. The symmetry of an implosion is an important factor in the yield generated from the resulting fusion process. The x-ray images are analyzed by decomposing the image intensity contours into Fourier and Legendre modes. This paper focuses on the additional protocols for the time-integrated shape analysis from image plates. For implosions with temperatures above ∼4 keV, the hard x-ray background can be utilized to infer the temperature of the hot spot.

Characterization of x-ray framing cameras for the National Ignition Facility using single photon pulse height analysis.

PubMed

Holder, J P; Benedetti, L R; Bradley, D K

2016-11-01

Single hit pulse height analysis is applied to National Ignition Facility x-ray framing cameras to quantify gain and gain variation in a single micro-channel plate-based instrument. This method allows the separation of gain from detectability in these photon-detecting devices. While pulse heights measured by standard-DC calibration methods follow the expected exponential distribution at the limit of a compound-Poisson process, gain-gated pulse heights follow a more complex distribution that may be approximated as a weighted sum of a few exponentials. We can reproduce this behavior with a simple statistical-sampling model.

Proton Radiography of a Thermal Explosion in PBX9501

NASA Astrophysics Data System (ADS)

Smilowitz, L.; Henson, B. F.; Romero, J. J.; Sandstrom, M. M.; Asay, B. W.; Schwartz, C.; Saunders, A.; Merrill, F.; Morris, C.; Murray, M. M.; McNeil, W. V.; Marr-Lyon, M.; Rightley, P. M.

2007-12-01

The understanding of thermal explosions and burn propagation lags that of detonations and shock propagation. Diagnostics such as high energy radiography have been used to image shocks, but have been previously precluded from use in thermal explosions due to their stringent timing requirements: shock propagation can be synchronized to an external diagnostic while thermal explosion can not. This issue is solved by following the evolution of the ignition volume in a thermal explosion and using a laser pulse to provide a temperature jump in that central volume during the final thermal runaway leading to ignition. Thermal explosion experiments have been conducted at the Los Alamos Proton Radiography facility and have yielded images of the evolution of ignition, post-ignition burn propagation, and case failure in a radially confined cylinder of PBX 9501. This paper presents images taken during the hours long quasistatic heating, the final minutes of thermal runaway, and the post ignition burn propagation.

X-33 Combustion-Wave Ignition System Tested

NASA Technical Reports Server (NTRS)

Liou, Larry C.

1999-01-01

The NASA Lewis Research Center, in cooperation with Rocketdyne, the Boeing Company, tested a novel rocket engine ignition system, called the combustion-wave ignition system, in its Research Combustion Laboratory. This ignition system greatly simplifies ignition in rocket engines that have a large number of combustors. The particular system tested was designed and fabricated by Rocketdyne for the national experimental spacecraft, X-33, which uses Rocketdyne s aerospike rocket engines. The goal of the tests was to verify the system design and define its operational characteristics. Results will contribute to the eventual successful flight of X-33. Furthermore, the combustion-wave ignition system, after it is better understood and refined on the basis of the test results and, later, flight-proven onboard X-33, could become an important candidate engine ignition system for our Nation s next-generation reusable launch vehicle.

Cryogenci DT and D2 Targets for Inertial Confinement Fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sangster, T.C.; Betti, R.; Craxton, R.S.

Ignition target designs for inertial confinement fusion on the National Ignition Facility (NIF) are based on a spherical ablator containing a solid, cryogenic-fuel layer of deuterium and tritium. The need for solid-fuel layers was recognized more than 30 years ago and considerable effort has resulted in the production of cryogenic targets that meet most of the critical fabrication tolerances for ignition on the NIf. Significant progress with the formation and characterization of cryogenic targets for both direct and x-ray drive will be described. Results from recent cryogenic implosions will also be presented.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Jaekyun; Kim, Myung -Gil; Kim, Jaehyun

The success of silicon based high density integrated circuits ignited explosive expansion of microelectronics. Although the inorganic semiconductors have shown superior carrier mobilities for conventional high speed switching devices, the emergence of unconventional applications, such as flexible electronics, highly sensitive photosensors, large area sensor array, and tailored optoelectronics, brought intensive research on next generation electronic materials. The rationally designed multifunctional soft electronic materials, organic and carbon-based semiconductors, are demonstrated with low-cost solution process, exceptional mechanical stability, and on-demand optoelectronic properties. Unfortunately, the industrial implementation of the soft electronic materials has been hindered due to lack of scalable fine-patterning methods. Inmore » this report, we demonstrated facile general route for high throughput sub-micron patterning of soft materials, using spatially selective deep-ultraviolet irradiation. For organic and carbon-based materials, the highly energetic photons (e.g. deep-ultraviolet rays) enable direct photo-conversion from conducting/semiconducting to insulating state through molecular dissociation and disordering with spatial resolution down to a sub-μm-scale. As a result, the successful demonstration of organic semiconductor circuitry promise our result proliferate industrial adoption of soft materials for next generation electronics.« less

Development and use of hydrogen-air torches in an altitude facility

NASA Technical Reports Server (NTRS)

Lottig, Roy A.; Huber, Gary T.

1993-01-01

A hydrogen-air ignition torch concept that had been used successfully in two rocket engine test facilities to consume excess hydrogen in their exhausters at atmospheric conditions was experimentally evaluated and developed in an altitude test facility at NASA Lewis Research Center. The idea was to use several of these torches in conjunction with hydrogen detectors and dilution air to prevent excess accumulation of unburned hydrogen or mixtures of hydrogen and air exceeding the sea-level lower flammability limit in the altitude facility exhaust system during hydrogen-fueled propulsion system tests. The torches were evaluated for a range of fuel-to-air ratios from 0.09 to 0.39 and for a range of exit diameters from 19/64 to 49/64 in. From the results of these tests a torch geometry and a fuel-to-air ratio were selected that produced a reasonably sized torch exhaust flame for consumption of unburned hydrogen at altitude pressures from sea level to 4 psia.

Measurement of Preheat and Shock Melting in Be Ablators During the First Few ns of the NIF Ignition Pulse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bradley, D K; Prisbrey, S T; Page, R H

2008-05-28

We have developed a scaled hohlraum platform to experimentally measure preheat in ablator materials during the first few nanoseconds of the radiation drive proposed for ignition experiments at the National Ignition Facility [J. A. Paisner, J. D. Boyes, S. A. Kumpan, et al., Laser Focus World 30, 75 (1994)]. The platform design approximates the radiation environment of the pole of the capsule by matching both the laser spot intensity and illuminated hohlraum wall fraction in scaled halfraums driven by the OMEGA laser system [T. R. Boehly, D. L. Brown, R. S. Craxton, et al., Optics Communications 133, 495 (1997)]. Amore » VISAR reflecting from the rear surface of the sample was used to measure sample motion prior to shock breakout. The experiments show that the first {approx}20 {micro}m of a Be ablator will be melted by radiation preheat, with subsequent material melted by the initial shock, in agreement with simulations. The experiments also show no evidence of anomalous heating of buried high-z doped layers in the ablator.« less

33 CFR 183.440 - Secondary circuits of ignition systems.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Requirements § 183.440 Secondary circuits of ignition systems. (a) Each conductor in a secondary circuit of an ignition system must meet SAE Standard J557. (b) The connection of each ignition conductor to a spark plug...

33 CFR 183.440 - Secondary circuits of ignition systems.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Requirements § 183.440 Secondary circuits of ignition systems. (a) Each conductor in a secondary circuit of an ignition system must meet SAE Standard J557. (b) The connection of each ignition conductor to a spark plug...

Improved Confinement Regimes and the Ignitor Experiment

NASA Astrophysics Data System (ADS)

Bombarda, F.; Coppi, B.; Detragiache, P.

2013-10-01

The Ignitor experiment is the only one designed and planned to reach ignition under controlled DT burning conditions. The machine prameters have been established on the basis of existing knowledge of the confinement properties of high density plasmas. The optimal plasma evolution in order to reach ignition by means of Ohmic heating only, without the contribution of transport barriers has been identified. Improved confinement regimes are expected to be accessible by means of the available ICRH additional heating power and the injection of pellets for density profile control. Moreover, ECRH of the outer edge of the (toroidal) plasma column has been proposed using very high frequency sources developed in Russia. Ignition can then be reached at slightly reduced machine parameters. Significant exploration of the behavior of burning, sub-ignited plasmas can be carried out in less demanding operational conditions than those needed for ignition with plasmas accessing the I or H-regimes. These conditions will be discussed together with the provisions made in order to maintain the required (for ignition) degree of plasma purity. Sponsored in part by the U.S. DOE.

Aerospace Laser Ignition/Ablation Variable High Precision Thruster

NASA Technical Reports Server (NTRS)

Campbell, Jonathan W. (Inventor); Edwards, David L. (Inventor); Campbell, Jason J. (Inventor)

2015-01-01

A laser ignition/ablation propulsion system that captures the advantages of both liquid and solid propulsion. A reel system is used to move a propellant tape containing a plurality of propellant material targets through an ignition chamber. When a propellant target is in the ignition chamber, a laser beam from a laser positioned above the ignition chamber strikes the propellant target, igniting the propellant material and resulting in a thrust impulse. The propellant tape is advanced, carrying another propellant target into the ignition chamber. The propellant tape and ignition chamber are designed to ensure that each ignition event is isolated from the remaining propellant targets. Thrust and specific impulse may by precisely controlled by varying the synchronized propellant tape/laser speed. The laser ignition/ablation propulsion system may be scaled for use in small and large applications.

Internal combustion engine controls for reduced exhausts contaminants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matthews, D.R. Jr.

1974-06-04

An electrochemical control system for achieving optimum efficiency in the catalytic conversion of hydrocarbon and carbon monoxide emissions from internal combustion engines is described. The system automatically maintains catalyst temperature at a point for maximum pollutant conversion by adjusting ignition timing and fuel/air ratio during warm-up and subsequent operation. Ignition timing is retarded during engine warm-up to bring the catalytic converter to an efficient operating temperature within a minimum period of time. After the converter reaches a predetermined minimum temperature, the spark is advanced to within its normal operating range. A needle-valve adjustment during warm-up is employed to enrich themore » fuel/air mixture by approximately 10 percent. Following warm-up and attainment of a predetermined catalyst temperature, the needle valve is moved automatically to its normal position (e.g., a fuel/air ratio of 16:1). Although the normal lean mixture causes increased amounts of nitrogen oxide emissions, present NO/sub x/ converters appear capable of handling the increased emissions under normal operating conditions.« less

Cherenkov radiation conversion and collection considerations for a gamma bang time/reaction history diagnostic for the NIF.

PubMed

Herrmann, Hans W; Mack, Joseph M; Young, Carlton S; Malone, Robert M; Stoeffl, Wolfgang; Horsfield, Colin J

2008-10-01

Bang time and reaction history measurements are fundamental components of diagnosing inertial confinement fusion (ICF) implosions and will be essential contributors to diagnosing attempts at ignition on the National Ignition Facility (NIF). Fusion gammas provide a direct measure of fusion interaction rate without being compromised by Doppler spreading. Gamma-based gas Cherenkov detectors that convert fusion gamma rays to optical Cherenkov photons for collection by fast recording systems have been developed and fielded at Omega. These systems have established their usefulness in illuminating ICF physics in several experimental campaigns. Bang time precision better than 25 ps has been demonstrated, well below the 50 ps accuracy requirement defined by the NIF system design requirements. A comprehensive, validated numerical study of candidate systems is providing essential information needed to make a down selection based on optimization of sensitivity, bandwidth, dynamic range, cost, and NIF logistics. This paper presents basic design considerations arising from the two-step conversion process from gamma rays to relativistic electrons to UV/visible Cherenkov radiation.

14 CFR 33.69 - Ignitions system.

Code of Federal Regulations, 2013 CFR

2013-01-01

... STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.69 Ignitions system. Each..., except that only one igniter is required for fuel burning augmentation systems. [Amdt. 33-6, 39 FR 35466... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Ignitions system. 33.69 Section 33.69...

14 CFR 33.69 - Ignitions system.

Code of Federal Regulations, 2014 CFR

2014-01-01

... STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.69 Ignitions system. Each..., except that only one igniter is required for fuel burning augmentation systems. [Amdt. 33-6, 39 FR 35466... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Ignitions system. 33.69 Section 33.69...

14 CFR 33.69 - Ignitions system.

Code of Federal Regulations, 2012 CFR

2012-01-01

... STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.69 Ignitions system. Each..., except that only one igniter is required for fuel burning augmentation systems. [Amdt. 33-6, 39 FR 35466... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Ignitions system. 33.69 Section 33.69...

14 CFR 23.1165 - Engine ignition systems.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Engine ignition systems. 23.1165 Section 23... Controls and Accessories § 23.1165 Engine ignition systems. (a) Each battery ignition system must be... allow continued engine operation if any battery becomes depleted. (b) The capacity of batteries and...

14 CFR 29.1165 - Engine ignition systems.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Engine ignition systems. 29.1165 Section 29... Engine ignition systems. (a) Each battery ignition system must be supplemented with a generator that is automatically available as an alternate source of electrical energy to allow continued engine operation if any...

14 CFR 23.1165 - Engine ignition systems.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Engine ignition systems. 23.1165 Section 23... Controls and Accessories § 23.1165 Engine ignition systems. (a) Each battery ignition system must be... allow continued engine operation if any battery becomes depleted. (b) The capacity of batteries and...

14 CFR 29.1165 - Engine ignition systems.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Engine ignition systems. 29.1165 Section 29... Engine ignition systems. (a) Each battery ignition system must be supplemented with a generator that is automatically available as an alternate source of electrical energy to allow continued engine operation if any...

14 CFR 23.1165 - Engine ignition systems.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Engine ignition systems. 23.1165 Section 23... Controls and Accessories § 23.1165 Engine ignition systems. (a) Each battery ignition system must be... allow continued engine operation if any battery becomes depleted. (b) The capacity of batteries and...

14 CFR 29.1165 - Engine ignition systems.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Engine ignition systems. 29.1165 Section 29... Engine ignition systems. (a) Each battery ignition system must be supplemented with a generator that is automatically available as an alternate source of electrical energy to allow continued engine operation if any...

14 CFR 25.1165 - Engine ignition systems.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Engine ignition systems. 25.1165 Section 25... Engine ignition systems. (a) Each battery ignition system must be supplemented by a generator that is automatically available as an alternate source of electrical energy to allow continued engine operation if any...

First Liquid Layer Inertial Confinement Fusion Implosions at the National Ignition Facility

DOE PAGES

Olson, R. E.; Leeper, R. J.; Kline, J. L.; ...

2016-12-07

The first cryogenic deuterium and deuterium-tritium liquid layer implosions at the National Ignition Facility (NIF) demonstrate D 2 and DT layer Inertial Confinement Fusion (ICF) implosions that can access low-to-moderate hot spot convergence ratio (1230) DT ice layer implosions. Although high CR is desirable in an idealized 1D sense, it amplifies the deleterious effects of asymmetries. To date, these asymmetries prevented the achievement of ignition at the NIF and are the major cause of simulation-experiment disagreement. In the initial liquid layer experiments, high neutron yields were achieved with CR’s of 12-17, and the hot spot formation is well understood, demonstratedmore » by good agreement between the experimental data and the radiation hydrodynamic simulations. These initial experiments open a new NIF experimental capability that provides an opportunity to explore the relationship between hot-spot convergence ratio and the robustness of hot-spot formation during ICF implosions.« less

First Liquid Layer Inertial Confinement Fusion Implosions at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Olson, R. E.; Leeper, R. J.; Kline, J. L.; Zylstra, A. B.; Yi, S. A.; Biener, J.; Braun, T.; Kozioziemski, B. J.; Sater, J. D.; Bradley, P. A.; Peterson, R. R.; Haines, B. M.; Yin, L.; Berzak Hopkins, L. F.; Meezan, N. B.; Walters, C.; Biener, M. M.; Kong, C.; Crippen, J. W.; Kyrala, G. A.; Shah, R. C.; Herrmann, H. W.; Wilson, D. C.; Hamza, A. V.; Nikroo, A.; Batha, S. H.

2016-12-01

The first cryogenic deuterium and deuterium-tritium liquid layer implosions at the National Ignition Facility (NIF) demonstrate D2 and DT layer inertial confinement fusion (ICF) implosions that can access a low-to-moderate hot-spot convergence ratio (12 30 ) DT ice layer implosions. Although high CR is desirable in an idealized 1D sense, it amplifies the deleterious effects of asymmetries. To date, these asymmetries prevented the achievement of ignition at the NIF and are the major cause of simulation-experiment disagreement. In the initial liquid layer experiments, high neutron yields were achieved with CRs of 12-17, and the hot-spot formation is well understood, demonstrated by a good agreement between the experimental data and the radiation hydrodynamic simulations. These initial experiments open a new NIF experimental capability that provides an opportunity to explore the relationship between hot-spot convergence ratio and the robustness of hot-spot formation during ICF implosions.

ICF Annual Report 1997

DOE Office of Scientific and Technical Information (OSTI.GOV)

Correll, D

The continuing objective of Lawrence Livermore National Laboratory's (LLNL's) Inertial Confinement Fusion (ICF) Program is the demonstration of thermonuclear fusion ignition and energy gain in the laboratory and to support the nuclear weapons program in its use of ICF facilities. The underlying theme of all ICF activities as a science research and development program is the Department of Energy's (DOE's) Defense Programs (DP) science-based Stockpile Stewardship Program (SSP). The mission of the US Inertial Fusion Program is twofold: (1) to address high-energy-density physics issues for the SSP and (2) to develop a laboratory microfusion capability for defense and energy applications.more » In pursuit of this mission, the ICF Program has developed a state-of-the-art capability to investigate high-energy-density physics in the laboratory. The near-term goals pursued by the ICF Program in support of its mission are demonstrating fusion ignition in the laboratory and expanding the Program's capabilities in high-energy-density science. The National Ignition Facility (NIF) project is a cornerstone of this effort.« less

Exploring the limits of case-to-capsule ratio, pulse length, and picket energy for symmetric hohlraum drive on the National Ignition Facility Laser

NASA Astrophysics Data System (ADS)

Callahan, D. A.; Hurricane, O. A.; Ralph, J. E.; Thomas, C. A.; Baker, K. L.; Benedetti, L. R.; Berzak Hopkins, L. F.; Casey, D. T.; Chapman, T.; Czajka, C. E.; Dewald, E. L.; Divol, L.; Döppner, T.; Hinkel, D. E.; Hohenberger, M.; Jarrott, L. C.; Khan, S. F.; Kritcher, A. L.; Landen, O. L.; LePape, S.; MacLaren, S. A.; Masse, L. P.; Meezan, N. B.; Pak, A. E.; Salmonson, J. D.; Woods, D. T.; Izumi, N.; Ma, T.; Mariscal, D. A.; Nagel, S. R.; Kline, J. L.; Kyrala, G. A.; Loomis, E. N.; Yi, S. A.; Zylstra, A. B.; Batha, S. H.

2018-05-01

We present a data-based model for low mode asymmetry in low gas-fill hohlraum experiments on the National Ignition Facility {NIF [Moses et al., Fusion Sci. Technol. 69, 1 (2016)]} laser. This model is based on the hypothesis that the asymmetry in these low fill hohlraums is dominated by the hydrodynamics of the expanding, low density, high-Z (gold or uranium) "bubble," which occurs where the intense outer cone laser beams hit the high-Z hohlraum wall. We developed a simple model which states that the implosion symmetry becomes more oblate as the high-Z bubble size becomes large compared to the hohlraum radius or the capsule size becomes large compared to the hohlraum radius. This simple model captures the trends that we see in data that span much of the parameter space of interest for NIF ignition experiments. We are now using this model as a constraint on new designs for experiments on the NIF.

Three-Dimensional Simulations of Flat-Foil Laser-Imprint Experiments at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Shvydky, A.; Radha, P. B.; Rosenberg, M. J.; Anderson, K. S.; Goncharov, V. N.; Marozas, J. A.; Marshall, F. J.; McKenty, P. W.; Regan, S. P.; Sangster, T. C.; Hohenberger, M.; di Nicola, J. M.; Koning, J. M.; Marinak, M. M.; Masse, L.; Karasik, M.

2017-10-01

Control of shell nonuniformities imprinted by the laser and amplified by hydrodynamic instabilities in the imploding target is critical for the success of direct-drive ignition at the National Ignition Facility (NIF). To measure a level of imprint and its reduction by the NIF smoothing by spectral dispersion (SSD), we performed experiments that employed flat CH foils driven with a single NIF beam with either no SSD or the NIF indirect-drive SSD applied to the laser pulse. Face-on x-ray radiography was used to measure optical depth variations, from which the amplitudes of the foil areal-density modulations were obtained. Results of 3-D, radiation-hydrodynamic code HYDRA simulations of the growth of the imprint-seeded perturbations are presented and compared with the experimental data. This work was supported by the U.S. Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944 and under the auspices of the Lawrence Livermore National Security, LLC, (LLNS) under Contract Number DE-AC52-07NA27344.

First Liquid Layer Inertial Confinement Fusion Implosions at the National Ignition Facility.

PubMed

Olson, R E; Leeper, R J; Kline, J L; Zylstra, A B; Yi, S A; Biener, J; Braun, T; Kozioziemski, B J; Sater, J D; Bradley, P A; Peterson, R R; Haines, B M; Yin, L; Berzak Hopkins, L F; Meezan, N B; Walters, C; Biener, M M; Kong, C; Crippen, J W; Kyrala, G A; Shah, R C; Herrmann, H W; Wilson, D C; Hamza, A V; Nikroo, A; Batha, S H

2016-12-09

The first cryogenic deuterium and deuterium-tritium liquid layer implosions at the National Ignition Facility (NIF) demonstrate D_{2} and DT layer inertial confinement fusion (ICF) implosions that can access a low-to-moderate hot-spot convergence ratio (1230) DT ice layer implosions. Although high CR is desirable in an idealized 1D sense, it amplifies the deleterious effects of asymmetries. To date, these asymmetries prevented the achievement of ignition at the NIF and are the major cause of simulation-experiment disagreement. In the initial liquid layer experiments, high neutron yields were achieved with CRs of 12-17, and the hot-spot formation is well understood, demonstrated by a good agreement between the experimental data and the radiation hydrodynamic simulations. These initial experiments open a new NIF experimental capability that provides an opportunity to explore the relationship between hot-spot convergence ratio and the robustness of hot-spot formation during ICF implosions.

Capsule Performance Optimization for the National Ignition Facility

NASA Astrophysics Data System (ADS)

Landen, Otto

2009-11-01

The overall goal of the capsule performance optimization campaign is to maximize the probability of ignition by experimentally correcting for likely residual uncertainties in the implosion and hohlraum physics used in our radiation-hydrodynamic computational models before proceeding to cryogenic-layered implosions and ignition attempts. This will be accomplished using a variety of targets that will set key laser, hohlraum and capsule parameters to maximize ignition capsule implosion velocity, while minimizing fuel adiabat, core shape asymmetry and ablator-fuel mix. The targets include high Z re-emission spheres setting foot symmetry through foot cone power balance [1], liquid Deuterium-filled ``keyhole'' targets setting shock speed and timing through the laser power profile [2], symmetry capsules setting peak cone power balance and hohlraum length [3], and streaked x-ray backlit imploding capsules setting ablator thickness [4]. We will show how results from successful tuning technique demonstration shots performed at the Omega facility under scaled hohlraum and capsule conditions relevant to the ignition design meet the required sensitivity and accuracy. We will also present estimates of all expected random and systematic uncertainties in setting the key ignition laser and target parameters due to residual measurement, calibration, cross-coupling, surrogacy, and scale-up errors, and show that these get reduced after a number of shots and iterations to meet an acceptable level of residual uncertainty. Finally, we will present results from upcoming tuning technique validation shots performed at NIF at near full-scale. Prepared by LLNL under Contract DE-AC52-07NA27344. [4pt] [1] E. Dewald, et. al. Rev. Sci. Instrum. 79 (2008) 10E903. [0pt] [2] T.R. Boehly, et. al., Phys. Plasmas 16 (2009) 056302. [0pt] [3] G. Kyrala, et. al., BAPS 53 (2008) 247. [0pt] [4] D. Hicks, et. al., BAPS 53 (2008) 2.

Hot-spot mix in ignition-scale implosions on the NIF [Hot-spot mix in ignition-scale implosions on the National Ignition Facility (NIF)

DOE PAGES

Regan, S. P.; Epstein, R.; Hammel, B. A.; ...

2012-03-30

Ignition of an inertial confinement fusion (ICF) target depends on the formation of a central hot spot with sufficient temperature and areal density. Radiative and conductive losses from the hot spot can be enhanced by hydrodynamic instabilities. The concentric spherical layers of current National Ignition Facility (NIF) ignition targets consist of a plastic ablator surrounding 2 a thin shell of cryogenic thermonuclear fuel (i.e., hydrogen isotopes), with fuel vapor filling the interior volume. The Rev. 5 ablator is doped with Ge to minimize preheat of the ablator closest to the DT ice caused by Au M-band emission from the hohlraummore » x-ray drive. Richtmyer–Meshkov and Rayleigh–Taylor hydrodynamic instabilities seeded by high-mode (50 < t < 200) ablator-surface perturbations can cause Ge-doped ablator to mix into the interior of the shell at the end of the acceleration phase. As the shell decelerates, it compresses the fuel vapor, forming a hot spot. K-shell line emission from the ionized Ge that has penetrated into the hot spot provides an experimental signature of hot-spot mix. The Ge emission from tritium–hydrogen–deuterium (THD) and DT cryogenic targets and gas-filled plastic shell capsules, which replace the THD layer with a massequivalent CH layer, was examined. The inferred amount of hot-spot mix mass, estimated from the Ge K-shell line brightness using a detailed atomic physics code, is typically below the 75 ng allowance for hot-spot mix. Furthermore, predictions of a simple mix model, based on linear growth of the measured surface-mass modulations, are consistent with the experimental results.« less

Hot-spot mix in ignition-scale implosions on the NIF [Hot-spot mix in ignition-scale implosions on the National Ignition Facility (NIF)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Regan, S. P.; Epstein, R.; Hammel, B. A.

Ignition of an inertial confinement fusion (ICF) target depends on the formation of a central hot spot with sufficient temperature and areal density. Radiative and conductive losses from the hot spot can be enhanced by hydrodynamic instabilities. The concentric spherical layers of current National Ignition Facility (NIF) ignition targets consist of a plastic ablator surrounding 2 a thin shell of cryogenic thermonuclear fuel (i.e., hydrogen isotopes), with fuel vapor filling the interior volume. The Rev. 5 ablator is doped with Ge to minimize preheat of the ablator closest to the DT ice caused by Au M-band emission from the hohlraummore » x-ray drive. Richtmyer–Meshkov and Rayleigh–Taylor hydrodynamic instabilities seeded by high-mode (50 < t < 200) ablator-surface perturbations can cause Ge-doped ablator to mix into the interior of the shell at the end of the acceleration phase. As the shell decelerates, it compresses the fuel vapor, forming a hot spot. K-shell line emission from the ionized Ge that has penetrated into the hot spot provides an experimental signature of hot-spot mix. The Ge emission from tritium–hydrogen–deuterium (THD) and DT cryogenic targets and gas-filled plastic shell capsules, which replace the THD layer with a massequivalent CH layer, was examined. The inferred amount of hot-spot mix mass, estimated from the Ge K-shell line brightness using a detailed atomic physics code, is typically below the 75 ng allowance for hot-spot mix. Furthermore, predictions of a simple mix model, based on linear growth of the measured surface-mass modulations, are consistent with the experimental results.« less

Plasma mirror implementation on LFEX laser for ion and fast electron fast ignition

NASA Astrophysics Data System (ADS)

Morace, A.; Kojima, S.; Arikawa, Y.; Fujioka, S.; Yogo, A.; Tosaki, S.; Sakata, S.; Abe, Y.; Lee, S. H.; Matsuo, K.; Sagisaka, A.; Kondo, K.; Pirozhkov, A. S.; Norimatsu, T.; Jitsuno, T.; Miyanaga, N.; Shiraga, H.; Nakai, M.; Nishimura, H.; Azechi, H.

2017-12-01

In this work we report the successful implementation of plasma mirror (PM) technology on an LFEX laser facility at the Institute of Laser Engineering, Osaka University. The LFEX laser pulse was successfully refocused at the target chamber center (TCC) by means of a spherical plasma mirror, resulting in 5  ×  1018 W cm-2 laser intensity, with 45% reflectivity at a laser flux of about 90 J cm-2 on the PM. Experimental results show stable focusing and pointing of the LFEX pulse after PM refocusing. The contrast improvement was demonstrated by both cooler fast electron slope temperature distribution as well as by the ability to shoot sub-µm plastic foils obtaining proton beams with maximum energy exceeding 20 MeV. Experimental results are qualitatively reproduced by 2D particle in cell simulations.

Flow Effects on the Flammability Diagrams of Solid Fuels: Microgravity Influence on Ignition Delay

NASA Technical Reports Server (NTRS)

Cordova, J. L.; Walther, D. C.; Fernandez-Pello, A. C.; Steinhaus, T.; Torero, J. L.; Quintere, J. G.; Ross, H. D.

1999-01-01

The possibility of an accidental fire in space-based facilities is a primary concern of space exploration programs. Spacecraft environments generally present low velocity air currents produced by ventilation and heating systems (of the order of 0.1 m/s), and fluctuating oxygen concentrations around that of air due to CO2 removal systems. Recent experiments of flame spread in microgravity show the spread rate to be faster and the limiting oxygen concentration lower than in normal-gravity. To date, there is not a material flammability-testing protocol that specifically addresses issues related to microgravity conditions. The present project (FIST) aims to establish a testing methodology that is suitable for the specific conditions of reduced gravity. The concepts underlying the operation of the LIFT apparatus, ASTM-E 1321-93, have been used to develop the Forced-flow Ignition and flame-Spread Test (FIST). As in the LIFT, the FIST is used to obtain the flammability diagrams of the material, i.e., graphs of ignition delay time and flame spread rate as a function of the externally applied radiant flux, but under forced flow rather than natural convection conditions, and for different oxygen concentrations. Although the flammability diagrams are similar, the flammability properties obtained with the FIST are found to depend on the flow characteristics. A research program is currently underway with the purpose of implementing the FIST as a protocol to characterize the flammability performance of solid materials to be used in microgravity facilities. To this point, tests have been performed with the FIST apparatus in both normal-gravity and microgravity conditions to determine the effects of oxidizer flow characteristics on the flammability diagrams of polymethylmethacrylate (PMMA) fuel samples. The experiments are conducted at reduced gravity in a KC- 135 aircraft following a parabolic flight trajectory that provides up to 25 seconds of low gravity. The objective of the experiments is to obtain data of ignition delay and flame spread rate at low flow velocities (0.1 to 0.2 m/s), which cannot be obtained under normal gravity because of the natural convection induced flows (approx. 0.5 m/s). Due to the limited reduced gravity time, the data can only be obtained for high radiant fluxes, and are consequently limited in scope. These tests do, however, provide insight into the flammability diagram characteristics at low velocity and reduced gravity, and also into the implications of the flow-dependence of the flammability properties under environments similar to those encountered in space facilities.

Comparison of the recently proposed super-Marx generator approach to thermonuclear ignition with the deuterium-tritium laser fusion-fission hybrid concept by the Lawrence Livermore National Laboratory

DOE PAGES

Winterberg, F.

2009-01-01

The recently proposed super-Marx generator pure deuterium microdetonation ignition concept is compared to the Lawrence Livermore National Ignition Facility (NIF) Laser deuterium-tritium fusion-fission hybrid concept (LIFE). In a super-Marx generator, a large number of ordinary Marx generators charge up a much larger second stage ultrahigh voltage Marx generator from which for the ignition of a pure deuterium microexplosion an intense GeV ion beam can be extracted. Typical examples of the LIFE concept are a fusion gain of 30 and a fission gain of 10, making up a total gain of 300, with about ten times more energy released into fissionmore » as compared to fusion. This means the substantial release of fission products, as in fissionless pure fission reactors. In the super-Marx approach for the ignition of pure deuterium microdetonation, a gain of the same magnitude can, in theory, be reached. If feasible, the super-Marx generator deuterium ignition approach would make lasers obsolete as a means for the ignition of thermonuclear microexplosions.« less

Calibration of scintillation-light filters for neutron time-of-flight spectrometers at the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sayre, D. B., E-mail: sayre4@llnl.gov; Barbosa, F.; Caggiano, J. A.

Sixty-four neutral density filters constructed of metal plates with 88 apertures of varying diameter have been radiographed with a soft x-ray source and CCD camera at National Security Technologies, Livermore. An analysis of the radiographs fits the radial dependence of the apertures’ image intensities to sigmoid functions, which can describe the rapidly decreasing intensity towards the apertures’ edges. The fitted image intensities determine the relative attenuation value of each filter. Absolute attenuation values of several imaged filters, measured in situ during calibration experiments, normalize the relative quantities which are now used in analyses of neutron spectrometer data at the Nationalmore » Ignition Facility.« less

Calibration of scintillation-light filters for neutron time-of-flight spectrometers at the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sayre, D. B.; Barbosa, F.; Caggiano, J. A.

Sixty-four neutral density filters constructed of metal plates with 88 apertures of varying diameter have been radiographed with a soft x-ray source and CCD camera at National Security Technologies, Livermore. An analysis of the radiographs fits the radial dependence of the apertures’ image intensities to sigmoid functions, which can describe the rapidly decreasing intensity towards the apertures’ edges. Here, the fitted image intensities determine the relative attenuation value of each filter. Absolute attenuation values of several imaged filters, measured in situ during calibration experiments, normalize the relative quantities which are now used in analyses of neutron spectrometer data at themore » National Ignition Facility.« less

Three- and two-dimensional simulations of counter-propagating shear experiments at high energy densities at the National Ignition Facility

DOE PAGES

Wang, Ping; Zhou, Ye; MacLaren, Stephan A.; ...

2015-11-06

Three- and two-dimensional numerical studies have been carried out to simulate recent counter-propagating shear flow experiments on the National Ignition Facility. A multi-physics three-dimensional, time-dependent radiation hydrodynamics simulation code is used. Using a Reynolds Averaging Navier-Stokes model, we show that the evolution of the mixing layer width obtained from the simulations agrees well with that measured from the experiments. A sensitivity study is conducted to illustrate a 3D geometrical effect that could confuse the measurement at late times, if the energy drives from the two ends of the shock tube are asymmetric. Implications for future experiments are discussed.

Calibration of scintillation-light filters for neutron time-of-flight spectrometers at the National Ignition Facility

DOE PAGES

Sayre, D. B.; Barbosa, F.; Caggiano, J. A.; ...

2016-07-26

Sixty-four neutral density filters constructed of metal plates with 88 apertures of varying diameter have been radiographed with a soft x-ray source and CCD camera at National Security Technologies, Livermore. An analysis of the radiographs fits the radial dependence of the apertures’ image intensities to sigmoid functions, which can describe the rapidly decreasing intensity towards the apertures’ edges. Here, the fitted image intensities determine the relative attenuation value of each filter. Absolute attenuation values of several imaged filters, measured in situ during calibration experiments, normalize the relative quantities which are now used in analyses of neutron spectrometer data at themore » National Ignition Facility.« less

Signal and background considerations for the MRSt on the National Ignition Facility (NIF).

PubMed

Wink, C W; Frenje, J A; Hilsabeck, T J; Bionta, R; Khater, H Y; Gatu Johnson, M; Kilkenny, J D; Li, C K; Séguin, F H; Petrasso, R D

2016-11-01

A Magnetic Recoil Spectrometer (MRSt) has been conceptually designed for time-resolved measurements of the neutron spectrum at the National Ignition Facility. Using the MRSt, the goals are to measure the time-evolution of the spectrum with a time resolution of ∼20-ps and absolute accuracy better than 5%. To meet these goals, a detailed understanding and optimization of the signal and background characteristics are required. Through ion-optics, MCNP simulations, and detector-response calculations, it is demonstrated that the goals and a signal-to background >5-10 for the down-scattered neutron measurement are met if the background, consisting of ambient neutrons and gammas, at the MRSt is reduced 50-100 times.

Determination of relative krypton fission product yields from 14 MeV neutron induced fission of 238U at the National Ignition Facility

DOE PAGES

Edwards, E. R.; Cassata, W. S.; Velsko, C. A.; ...

2016-09-22

Precisely-known fission yield distributions are needed to determine a fissioning isotope and the incident neutron energy in nuclear security applications. 14 MeV neutrons from DT fusion at the National Ignition Facility (NIF) induce fission in depleted uranium (DU) contained in the target assembly hohlraum. The fission yields of Kr isotopes (85m, 87, 88, and 89) are measured relative to the cumulative yield of 88Kr and compared to previously tabulated values. Here, the results from this experiment and England and Rider are in agreement, except for the 85mKr/ 88Kr ratio, which may be the result of incorrect nuclear data.

Demonstration of a long pulse X-ray source at the National Ignition Facility

NASA Astrophysics Data System (ADS)

May, M. J.; Opachich, Y. P.; Kemp, G. E.; Colvin, J. D.; Barrios, M. A.; Widmann, K. W.; Fournier, K. B.; Hohenberger, M.; Albert, F.; Regan, S. P.

2017-04-01

A long duration high fluence x-ray source has been developed at the National Ignition Facility (NIF). The target was a 14.4 mm tall, 4.1 mm diameter, epoxy walled, gas filled pipe. Approximately 1.34 MJ from the NIF laser was used to heat the mixture of (55:45) Kr:Xe at 1.2 atm (˜5.59 mg/cm3) to emit in a fairly isotropic radiant intensity of 400-600 GW/sr from the Ephoton = 3-7 keV spectral range for a duration of ≈ 14 ns. The HYDRA simulated radiant intensities were in reasonable agreement with experiments but deviated at late times.

Note: Radiochemical measurement of fuel and ablator areal densities in cryogenic implosions at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Hagmann, C.; Shaughnessy, D. A.; Moody, K. J.; Grant, P. M.; Gharibyan, N.; Gostic, J. M.; Wooddy, P. T.; Torretto, P. C.; Bandong, B. B.; Bionta, R.; Cerjan, C. J.; Bernstein, L. A.; Caggiano, J. A.; Herrmann, H. W.; Knauer, J. P.; Sayre, D. B.; Schneider, D. H.; Henry, E. A.; Fortner, R. J.

2015-07-01

A new radiochemical method for determining deuterium-tritium (DT) fuel and plastic ablator (CH) areal densities (ρR) in high-convergence, cryogenic inertial confinement fusion implosions at the National Ignition Facility is described. It is based on measuring the 198Au/196Au activation ratio using the collected post-shot debris of the Au hohlraum. The Au ratio combined with the independently measured neutron down scatter ratio uniquely determines the areal densities ρR(DT) and ρR(CH) during burn in the context of a simple 1-dimensional capsule model. The results show larger than expected ρR(CH) values, hinting at the presence of cold fuel-ablator mix.

Variable convergence liquid layer implosions on the National Ignition Facility

DOE PAGES

Zylstra, A. B.; Yi, S. A.; Haines, B. M.; ...

2018-03-19

Liquid layer implosions using the “wetted foam” technique, where the liquid fuel is wicked into a supporting foam, have been recently conducted on the National Ignition Facility for the first time [Olson et al., Phys. Rev. Lett. 117, 245001 (2016)]. In this paper, we report on a series of wetted foam implosions where the convergence ratio was varied between 12 and 20. Reduced nuclear performance is observed as convergence ratio increases. 2-D radiation-hydrodynamics simulations accurately capture the performance at convergence ratios (CR) ~ 12, but we observe a significant discrepancy at CR ~ 20. Finally, this may be due tomore » suppressed hot-spot formation or an anomalous energy loss mechanism.« less

Variable convergence liquid layer implosions on the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zylstra, A. B.; Yi, S. A.; Haines, B. M.

Liquid layer implosions using the “wetted foam” technique, where the liquid fuel is wicked into a supporting foam, have been recently conducted on the National Ignition Facility for the first time [Olson et al., Phys. Rev. Lett. 117, 245001 (2016)]. In this paper, we report on a series of wetted foam implosions where the convergence ratio was varied between 12 and 20. Reduced nuclear performance is observed as convergence ratio increases. 2-D radiation-hydrodynamics simulations accurately capture the performance at convergence ratios (CR) ~ 12, but we observe a significant discrepancy at CR ~ 20. Finally, this may be due tomore » suppressed hot-spot formation or an anomalous energy loss mechanism.« less

Calibration of scintillation-light filters for neutron time-of-flight spectrometers at the National Ignition Facility.

PubMed

Sayre, D B; Barbosa, F; Caggiano, J A; DiPuccio, V N; Eckart, M J; Grim, G P; Hartouni, E P; Hatarik, R; Weber, F A

2016-11-01

Sixty-four neutral density filters constructed of metal plates with 88 apertures of varying diameter have been radiographed with a soft x-ray source and CCD camera at National Security Technologies, Livermore. An analysis of the radiographs fits the radial dependence of the apertures' image intensities to sigmoid functions, which can describe the rapidly decreasing intensity towards the apertures' edges. The fitted image intensities determine the relative attenuation value of each filter. Absolute attenuation values of several imaged filters, measured in situ during calibration experiments, normalize the relative quantities which are now used in analyses of neutron spectrometer data at the National Ignition Facility.

Determination of relative krypton fission product yields from 14 MeV neutron induced fission of 238U at the National Ignition Facility.

PubMed

Edwards, E R; Cassata, W S; Velsko, C A; Yeamans, C B; Shaughnessy, D A

2016-11-01

Precisely-known fission yield distributions are needed to determine a fissioning isotope and the incident neutron energy in nuclear security applications. 14 MeV neutrons from DT fusion at the National Ignition Facility induce fission in depleted uranium contained in the target assembly hohlraum. The fission yields of Kr isotopes (85m, 87, 88, and 89) are measured relative to the cumulative yield of 88 Kr and compared to previously tabulated values. The results from this experiment and England and Rider are in agreement, except for the 85m Kr/ 88 Kr ratio, which may be the result of incorrect nuclear data.

Development of the CD symcap platform to study gas-shell mix in implosions at the National Ignition Facility

DOE PAGES

Casey, D. T.; Smalyuk, V. A.; Tipton, R. E.; ...

2014-09-09

Surrogate implosions play an important role at the National Ignition Facility (NIF) for isolating aspects of the complex physical processes associated with fully integrated ignition experiments. The newly developed CD Symcap platform has been designed to study gas-shell mix in indirectly driven, pure T₂-gas filled CH-shell implosions equipped with 4 μm thick CD layers. This configuration provides a direct nuclear signature of mix as the DT yield (above a characterized D contamination background) is produced by D from the CD layer in the shell, mixing into the T-gas core. The CD layer can be placed at different locations within themore » CH shell to probe the depth and extent of mix. CD layers placed flush with the gas-shell interface and recessed up to 8 μm have shown that most of the mix occurs at the inner-shell surface. In addition, time-gated x-ray images of the hotspot show large brightly-radiating objects traversing through the hotspot around bang-time, which are likely chunks of CH/CD plastic. This platform is a powerful new capability at the NIF for understanding mix, one of the key performance issues for ignition experiments.« less

ASTM Committee G-4 metals flammability test program - Data and discussion

NASA Technical Reports Server (NTRS)

Stoltzfus, Joel M.; Homa, John M.; Williams, Ralph E.; Benz, Frank J.

1988-01-01

Results of metals flammability tests performed on twenty-six metals in the NASA/White Sands Test Facility are discussed together with the test systems. The promoted combustion and ignition characteristics of these metals are described, and the metals are ranked according to their suitability for use in oxygen systems. In general, alloys with high copper and nickel contents and low iron content were found to rank higher than those that had high iron content, while alloys that had high aluminum content were ranked the lowest.

Development and Testing of a Green Monopropellant Ignition System

NASA Technical Reports Server (NTRS)

Whitmore, Stephen A.; Merkley, Daniel P.; Eilers, Shannon D.; Judson, Michael I.; Taylor, Terry L.

2013-01-01

This paper will detail the development and testing of a "green" monopropellant booster ignition system. The proposed booster ignition technology eliminates the need for a pre-heated catalyst bed, a high wattage power source, toxic pyrophoric ignition fluids, or a bi-propellant spark ignitor. The design offers the simplicity of a monopropellant feed system features non-hazardous gaseous oxygen (GOX) as the working fluid. The approach is fundamentally different from all other "green propellant" solutions in the aerospace in the industry. Although the proposed system is more correctly a "hybrid" rocket technology, since only a single propellant feed path is required, it retains all the simple features of a monopropellant system. The technology is based on the principle of seeding an oxidizing flow with a small amount of hydrocarbon.1 The ignition is initiated electrostatically with a low-wattage inductive spark. Combustion gas byproducts from the hydrocarbon-seeding ignition process can exceed 2400 C and the high exhaust temperature ensures reliable main propellant ignition. The system design is described in detail in the Hydrocarbon-Seeded Ignition System Design subsection.

Technology Development of a Fiber Optic-Coupled Laser Ignition System for Multi-Combustor Rocket Engines

NASA Technical Reports Server (NTRS)

Trinh, Huu P.; Early, Jim; Osborne, Robin; Thomas, Matthew E.; Bossard, John A.

2002-01-01

This paper addresses the progress of technology development of a laser ignition system at NASA Marshall Space Flight Center (MSFC). The first two years of the project focus on comprehensive assessments and evaluations of a novel dual-pulse laser concept, flight- qualified laser system, and the technology required to integrate the laser ignition system to a rocket chamber. With collaborations of the Department of Energy/Los Alamos National Laboratory (LANL) and CFD Research Corporation (CFDRC), MSFC has conducted 26 hot fire ignition tests with lab-scale laser systems. These tests demonstrate the concept feasibility of dual-pulse laser ignition to initiate gaseous oxygen (GOX)/liquid kerosene (RP-1) combustion in a rocket chamber. Presently, a fiber optic- coupled miniaturized laser ignition prototype is being implemented at the rocket chamber test rig for future testing. Future work is guided by a technology road map that outlines the work required for maturing a laser ignition system. This road map defines activities for the next six years, with the goal of developing a flight-ready laser ignition system.

Propulsion system ignition overpressure for the Space Shuttle

NASA Technical Reports Server (NTRS)

Ryan, R. S.; Jones, J. H.; Guest, S. H.; Struck, H. G.; Rheinfurth, M. H.; Verferaime, V. S.

1981-01-01

Liquid and solid rocket motor propulsion systems create an overpressure wave during ignition, caused by the accelerating gas particles pushing against or displacing the air contained in the launch pad or launch facility and by the afterburning of the fuel-rich gases. This wave behaves as a blast or shock wave characterized by a positive triangular-shaped first pulse and a negative half-sine wave second pulse. The pulse travels up the space vehicle and has the potential of either overloading individual elements or exciting overall vehicle dynamics. The latter effect results from the phasing difference of the wave from one side of the vehicle to the other. This overpressure phasing, or delta P environment, because of its frequency content as well as amplitude, becomes a design driver for certain panels (e.g., thermal shields) and payloads for the Space Shuttle. The history of overpressure effects on the Space Shuttle, the basic overpressure phenomenon, Space Shuttle overpressure environment, scale model overpressure testing, and techniques for suppressing the overpressure environments are considered.

Mishaps with Oxygen in NASA Operations

NASA Technical Reports Server (NTRS)

Ordin, Paul M.

1971-01-01

Data from a substantial number of oxygen mishaps obtained from NASA and contractor records are presented. Information from several Air Force records, concerning oxygen accidents involving aircraft operations, are also included. Descriptions of the mishaps and their causes, for both liquid and gaseous oxygen in ground test facilities and space vehicle systems, are given. A number of safety regulations aimed at reducing the accident probability is discussed. The problems related to material compatibility and materials testing are considered, and the limited information on factors affecting the ignition of materials in oxygen is presented. In addition, details are given of several of the accident/incidents listed in order to define the combination of conditions causing the mishap. In addition to propellant system mishaps, accident/incidents which occurred in space and ground system structures were included, as well as those in electrical systems, ground support facilities, ordnance, and related operations.

A Comparative Study of Cycle Variability of Laser Plug Ignition vs Classical Spark Plug Ignition in Combustion Engines

NASA Astrophysics Data System (ADS)

Done, Bogdan

2017-10-01

Over the past 30 years numerous studies and laboratory experiments have researched the use of laser energy to ignite gas and fuel-air mixtures. The actual implementation of this laser application has still to be fully achieved in a commercial automotive application. Laser Plug Ignition as a replacement for Spark Plug Ignition in the internal combustion engines of automotive vehicles, offers several potential benefits such as extending lean burn capability, reducing the cyclic variability between combustion cycles and decreasing the total amount of ignition costs, and implicitly weight and energy requirements. The paper presents preliminary results of cycle variability study carried on a SI Engine equipped with laser Plug Ignition system. Versus classic ignition system, the use of the laser Plug Ignition system assures the reduction of the combustion process variability, reflected in the lower values of the coefficient of variability evaluated for indicated mean effective pressure, maximum pressure, maximum pressure angle and maximum pressure rise rate. The laser plug ignition system was mounted on an experimental spark ignition engine and tested at the regime of 90% load and 2800 rev/min, at dosage of λ=1.1. Compared to conventional spark plug, laser ignition assures the efficiency at lean dosage.

14 CFR 33.37 - Ignition system.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ignition system. 33.37 Section 33.37 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Reciprocating Aircraft Engines § 33.37 Ignition system. Each spark ignition engine must have a...

Compressed Natural Gas Vehicle Maintenance Facility Modification Handbook

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelly, Kay L.; Ramsden, Margo M.; Gonzales, John E.

To ensure the safety of personnel and facilities, vehicle maintenance facilities are required by law and by guidelines of the National Fire Protection Association (NFPA) and the International Fire Code (IFC) to exhibit certain design features. They are also required to be fitted with certain fire protection equipment and devices because of the potential for fire or explosion in the event of fuel leakage or spills. All fuels have an explosion or fire potential if specific conditions are present. The hazard presented by liquid fuels, such as gasoline and diesel, results from the spillage of these liquids and subsequent ignitionmore » of vapors, causing a fire or explosion. Facilities that maintain liquid-fueled vehicles and implement appropriate safety measures are protected with ventilation systems designed to capture liquid fuel vapors at or near floor level. To minimize the potential for ignition in the event of a spill, receptacles, electrical fixtures, and hot-work operations, such as welding, are located outside of these areas. Compressed natural gas (CNG) is composed of methane with slight amounts of heavier simple hydrocarbons. Maintenance facilities that maintain CNG vehicles indoors must be protected against fire and explosion. However, the means of ensuring safety are different from those employed for liquid fuels because of the gaseous nature of methane and the fact that it is lighter than air. Because CNG is lighter than air, a release will rise to the ceiling of the maintenance facility and quickly dissipate rather than remaining at or near floor level like liquid fuel vapors. Although some of the means of protection for CNG vehicle maintenance facilities are similar to those used for liquid-fueled vehicles (ventilation and elimination of ignition sources), the types and placement of the protection equipment are different because of the behavior of the different fuels. The nature of gaseous methane may also require additional safeguards, such as combustible gas detectors and control systems, or specialized space heating, which are not needed in facilities servicing liquid-fuel vehicles. This handbook covers maintenance facilities that service CNG-fueled vehicles. Although similar requirements are mandated for liquefied natural gas (LNG) or liquefied petroleum gas (LPG) fueled vehicles, LNG and LPG are not covered in this handbook.« less

The National Ignition Facility (NIF) as a User Facility

NASA Astrophysics Data System (ADS)

Keane, Christopher; NIF Team

2013-10-01

The National Ignition Facility (NIF) has made significant progress towards operation as a user facility. Through June 2013, NIF conducted over 1200 experiments in support of ICF, HED science, and development of facility capabilities. The NIF laser has met or achieved all specifications and a wide variety of diagnostic and target fabrication capabilities are in place. A NIF User Group and associated Executive Board have been formed. Two User Group meetings have been conducted since formation of the User Group. NIF experiments in fundamental science have provided important new results. NIF ramp compression experiments have been conducted using diamond and iron, with EOS results obtained at pressures up to approximately 50 Mbar and 8 Mbar, respectively. Initial experiments in supernova hydrodynamics, the fundamental physics of the Rayleigh-Taylor instability, and equation of state in the Gbar pressure regime have also been conducted. This presentation will discuss the fundamental science program at NIF, including the proposal solicitation and scientific review processes and other aspects of user facility operation. This work was performed under the auspices of the Lawrence Livermore National Security, LLC, (LLNS) under Contract No. DE-AC52-07NA27344.

National Ignition Facility, High-Energy-Density and Inertial Confinement Fusion, Peer-Review Panel (PRP) Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keane, C. J.

2014-01-28

The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) is operated as a National Nuclear Security Administration (NNSA) user facility in accordance with Department of Energy (DOE) best practices, including peer-reviewed experiments, regular external reviews of performance, and the use of a management structure that facilitates user and stakeholder feedback. NIF facility time is managed using processes similar to those in other DOE science facilities and is tailored to meet the mix of missions and customers that NIF supports. The NIF Governance Plan describes the process for allocating facility time on NIF and for creating the shot schedule.more » It also includes the flow of responsibility from entity to entity. The plan works to ensure that NIF meets its mission goals using the principles of scientific peer review, including transparency and cooperation among the sponsor, the NIF staff, and the various user communities. The NIF Governance Plan, dated September 28, 2012, was accepted and signed by LLNL Director Parney Albright, NIF Director Ed Moses, and Don Cook and Thomas D’Agostino of NNSA. Figure 1 shows the organizational structure for NIF Governance.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Opachich, Y.P.; Koch, J.A.; Haugh, M. J.

A multi wavelength, high contrast contact radiography system has been developed to characterize density variations in ultra-low density aerogel foams. These foams are used to generate a ramped pressure drive in materials strength experiments at the National Ignition Facility (NIF) and require precision characterization in order to reduce errors in measurements. The system was used to characterize density variations in carbon and silicon based aerogels to ~10.3% accuracy with ~30 μm spatial resolution. The system description, performance and measurement results collected using a 17.8 mg/cc carbon based JX–6 (C 20H 30) aerogel are discussed in this manuscript.

Design and Fabrication of Opacity Targets for the National Ignition Facility

DOE PAGES

Cardenas, Tana; Schmidt, Derek William; Dodd, Evan S.; ...

2017-12-22

Accurate models for opacity of partially ionized atoms are important for modeling and understanding stellar interiors and other high-energy-density phenomena such as inertial confinement fusion. Lawrence Livermore National Laboratory is leading a multilaboratory effort to conduct experiments on the National Ignition Facility (NIF) to try to reproduce recent opacity tests at the Sandia National Laboratory Z-facility. Since 2015, the NIF effort has evolved several hohlraum designs that consist of multiple pieces joined together. The target also has three components attached to the main stalk over a long distance with high tolerances that have resulted in several design iterations. The targetmore » has made use of rapid prototyped features to attach a capsule and collimator under the hohlraum while avoiding interference with the beams. Furthermore, this paper discusses the evolution of the hohlraum and overall target design and the challenges involved with fabricating and assembling these targets.« less

Design and Fabrication of Opacity Targets for the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cardenas, Tana; Schmidt, Derek William; Dodd, Evan S.

Accurate models for opacity of partially ionized atoms are important for modeling and understanding stellar interiors and other high-energy-density phenomena such as inertial confinement fusion. Lawrence Livermore National Laboratory is leading a multilaboratory effort to conduct experiments on the National Ignition Facility (NIF) to try to reproduce recent opacity tests at the Sandia National Laboratory Z-facility. Since 2015, the NIF effort has evolved several hohlraum designs that consist of multiple pieces joined together. The target also has three components attached to the main stalk over a long distance with high tolerances that have resulted in several design iterations. The targetmore » has made use of rapid prototyped features to attach a capsule and collimator under the hohlraum while avoiding interference with the beams. Furthermore, this paper discusses the evolution of the hohlraum and overall target design and the challenges involved with fabricating and assembling these targets.« less

High-resolution spectroscopy for Doppler-broadening ion temperature measurements of implosions at the National Ignition Facility.

PubMed

Koch, J A; Stewart, R E; Beiersdorfer, P; Shepherd, R; Schneider, M B; Miles, A R; Scott, H A; Smalyuk, V A; Hsing, W W

2012-10-01

Future implosion experiments at the national ignition facility (NIF) will endeavor to simultaneously measure electron and ion temperatures with temporal and spatial resolution in order to explore non-equilibrium temperature distributions and their relaxation toward equilibrium. In anticipation of these experiments, and with understanding of the constraints of the NIF facility environment, we have explored the use of Doppler broadening of mid-Z dopant emission lines, such as krypton He-α at 13 keV, as a diagnostic of time- and potentially space-resolved ion temperature. We have investigated a number of options analytically and with numerical raytracing, and we have identified several promising candidate spectrometer designs that meet the expected requirements of spectral and temporal resolution and data signal-to-noise ratio for gas-filled exploding pusher implosions, while providing maximum flexibility for use on a variety of experiments that potentially include burning plasma.

Processing method for superconducting ceramics

DOEpatents

Bloom, Ira D.; Poeppel, Roger B.; Flandermeyer, Brian K.

1993-01-01

A process for preparing a superconducting ceramic and particularly YBa.sub.2 Cu.sub.3 O.sub.7-.delta., where .delta. is in the order of about 0.1-0.4, is carried out using a polymeric binder which decomposes below its ignition point to reduce carbon residue between the grains of the sintered ceramic and a nonhydroxylic organic solvent to limit the problems with water or certain alcohols on the ceramic composition.

Processing method for superconducting ceramics

DOEpatents

Bloom, Ira D.; Poeppel, Roger B.; Flandermeyer, Brian K.

1993-02-02

A process for preparing a superconducting ceramic and particularly YBa.sub.2 Cu.sub.3 O.sub.7-.delta., where .delta. is in the order of about 0.1-0.4, is carried out using a polymeric binder which decomposes below its ignition point to reduce carbon residue between the grains of the sintered ceramic and a nonhydroxylic organic solvent to limit the problems with water or certain alcohols on the ceramic composition.

Characterization of HANARO neutron radiography facility in accordance with ASTM standard E545-91/E803-91 for KOLAS/ISO17025.

PubMed

Cheul-Muu, Sim; Ki-Yong, Nam; In-Cheol, Lim; Chang-Hee, Lee; Ha-Lim, Choi

2004-10-01

As neutron radiography is even more in demand for industrial applications of aircraft, turbine blade, automobile, explosive igniters, etc, it is necessary to review the standards which are the most appropriate for preparing the procedures for setting up the QA system. Recently, Korea Of Lab Accreditation Scheme (KOLAS) was originated from ISO 17025. It is widely recognized by research peer groups for conducting valid tests. The neutron radiography facility (NRF) of High Flux Advanced Neutron Application Reactor (HANARO), which started ion 1996, is the preliminary stages of KOLAS. The HANARO NRF is not only characterized using ASTM standards E545-91/E803-91 to satisfy the requirements of KOLAS, but in the design phase of the tomography system.

Wavelength-detuning cross-beam energy transfer mitigation scheme for direct drive: Modeling and evidence from National Ignition Facility implosions

NASA Astrophysics Data System (ADS)

Marozas, J. A.; Hohenberger, M.; Rosenberg, M. J.; Turnbull, D.; Collins, T. J. B.; Radha, P. B.; McKenty, P. W.; Zuegel, J. D.; Marshall, F. J.; Regan, S. P.; Sangster, T. C.; Seka, W.; Campbell, E. M.; Goncharov, V. N.; Bowers, M. W.; Di Nicola, J.-M. G.; Erbert, G.; MacGowan, B. J.; Pelz, L. J.; Moody, J.; Yang, S. T.

2018-05-01

Cross-beam energy transfer (CBET) results from two-beam energy exchange via seeded stimulated Brillouin scattering, which detrimentally reduces laser-energy absorption for direct-drive inertial confinement fusion. Consequently, ablation pressure and implosion velocity suffer from the decreased absorption, reducing target performance in both symmetric and polar direct drive. Additionally, CBET alters the time-resolved scattered-light spectra and redistributes absorbed and scattered-light-changing shell morphology and low-mode drive symmetry. Mitigating CBET is demonstrated in inertial confinement implosions at the National Ignition Facility by detuning the laser-source wavelengths (±2.3 Å UV) of the interacting beams. In polar direct drive, wavelength detuning was shown to increase the equatorial region velocity experimentally by 16% and to alter the in-flight shell morphology. These experimental observations are consistent with design predictions of radiation-hydrodynamic simulations that indicate a 10% increase in the average ablation pressure. These results indicate that wavelength detuning successfully mitigates CBET. Simulations predict that optimized phase plates and wavelength-detuning CBET mitigation utilizing the three-legged beam layout of the OMEGA Laser System significantly increase absorption and achieve >100-Gbar hot-spot pressures in symmetric direct drive.

Inertial Fusion and High-Energy-Density Science in the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tarter, C B

2001-09-06

Inertial fusion and high-energy density science worldwide is poised to take a great leap forward. In the US, programs at the University of Rochester, Sandia National Laboratories, Los Alamos National Laboratory, Lawrence Livermore National Laboratory (LLNL), the Naval Research Laboratory, and many smaller laboratories have laid the groundwork for building a facility in which fusion ignition can be studied in the laboratory for the first time. The National Ignition Facility (NIF) is being built by the Department of Energy's National Nuclear Security Agency to provide an experimental test bed for the US Stockpile Stewardship Program (SSP) to ensure the dependabilitymore » of the country's nuclear deterrent without underground nuclear testing. NIF and other large laser systems being planned such as the Laser MegaJoule (LMJ) in France will also make important contributions to basic science, the development of inertial fusion energy, and other scientific and technological endeavors. NIF will be able to produce extreme temperatures and pressures in matter. This will allow simulating astrophysical phenomena (on a tiny scale) and measuring the equation of state of material under conditions that exist in planetary cores.« less

Ignitability test method and apparatus

NASA Technical Reports Server (NTRS)

Bement, Laurence J. (Inventor); Bailey, James W. (Inventor); Schimmel, Morry L. (Inventor)

1991-01-01

An apparatus for testing ignitability of an initiator includes a body having a central cavity, an initiator holder for holding the initiator over the central cavity of the body, an ignition material holder disposed in the central cavity of the body and having a cavity facing the initiator holder which receives a measured quantity of ignition material to be ignited by the initiator. It contains a chamber in communication with the cavity of the ignition material and the central cavity of the body, and a measuring system for analyzing pressure characteristics generated by ignition of the ignition material by the initiator. The measuring system includes at least one transducer coupled with an oscillograph for recording pressure traces generated by ignition.

Shock ignition targets: gain and robustness vs ignition threshold factor

NASA Astrophysics Data System (ADS)

Atzeni, Stefano; Antonelli, Luca; Schiavi, Angelo; Picone, Silvia; Volponi, Gian Marco; Marocchino, Alberto

2017-10-01

Shock ignition is a laser direct-drive inertial confinement fusion scheme, in which the stages of compression and hot spot formation are partly separated. The hot spot is created at the end of the implosion by a converging shock driven by a final ``spike'' of the laser pulse. Several shock-ignition target concepts have been proposed and relevant gain curves computed (see, e.g.). Here, we consider both pure-DT targets and more facility-relevant targets with plastic ablator. The investigation is conducted with 1D and 2D hydrodynamic simulations. We determine ignition threshold factors ITF's (and their dependence on laser pulse parameters) by means of 1D simulations. 2D simulations indicate that robustness to long-scale perturbations increases with ITF. Gain curves (gain vs laser energy), for different ITF's, are generated using 1D simulations. Work partially supported by Sapienza Project C26A15YTMA, Sapienza 2016 (n. 257584), Eurofusion Project AWP17-ENR-IFE-CEA-01.

Design of the polar neutron-imaging aperture for use at the National Ignition Facility.

PubMed

Fatherley, V E; Barker, D A; Fittinghoff, D N; Hibbard, R L; Martinez, J I; Merrill, F E; Oertel, J A; Schmidt, D W; Volegov, P L; Wilde, C H

2016-11-01

The installation of a neutron imaging diagnostic with a polar view at the National Ignition Facility (NIF) required design of a new aperture, an extended pinhole array (PHA). This PHA is different from the pinhole array for the existing equatorial system due to significant changes in the alignment and recording systems. The complex set of component requirements, as well as significant space constraints in its intended location, makes the design of this aperture challenging. In addition, lessons learned from development of prior apertures mandate careful aperture metrology prior to first use. This paper discusses the PHA requirements, constraints, and the final design. The PHA design is complex due to size constraints, machining precision, assembly tolerances, and design requirements. When fully assembled, the aperture is a 15 mm × 15 mm × 200 mm tungsten and gold assembly. The PHA body is made from 2 layers of tungsten and 11 layers of gold. The gold layers include 4 layers containing penumbral openings, 4 layers containing pinholes and 3 spacer layers. In total, there are 64 individual, triangular pinholes with a field of view (FOV) of 200 μm and 6 penumbral apertures. Each pinhole is pointed to a slightly different location in the target plane, making the effective FOV of this PHA a 700 μm square in the target plane. The large FOV of the PHA reduces the alignment requirements both for the PHA and the target, allowing for alignment with a laser tracking system at NIF.

Development and Testing of a Methane/Oxygen Catalytic Microtube Ignition System for Rocket Propulsion

NASA Technical Reports Server (NTRS)

Deans, Matthew

2012-01-01

This study sought to develop a catalytic ignition advanced torch system with a unique catalyst microtube design that could serve as a low energy alternative or redundant system for the ignition of methane and oxygen rockets. Development and testing of iterations of hardware was carried out to create a system that could operate at altitude and produce a torch. A unique design was created that initiated ignition via the catalyst and then propagated into external staged ignition. This system was able to meet the goals of operating across a range of atmospheric and altitude conditions with power inputs on the order of 20 to 30 watts with chamber pressures and mass flow rates typical of comparable ignition systems for a 100 lbf engine.

Development and Testing of a Methane/Oxygen Catalytic Microtube Ignition System for Rocket Propulsion

NASA Technical Reports Server (NTRS)

Deans, Matthew C.; Schneider, Steven J.

2012-01-01

This study sought to develop a catalytic ignition advanced torch system with a unique catalyst microtube design that could serve as a low energy alternative or redundant system for the ignition of methane and oxygen rockets. Development and testing of iterations of hardware was carried out to create a system that could operate at altitude and produce a torch. A unique design was created that initiated ignition via the catalyst and then propagated into external staged ignition. This system was able to meet the goals of operating across a range of atmospheric and altitude conditions with power inputs on the order of 20 to 30 watts with chamber pressures and mass flow rates typical of comparable ignition systems for a 100 Ibf engine.

Catalyzed Ignition of Bipropellants in Microtubes

NASA Technical Reports Server (NTRS)

Schneider, Steven J.; Boyarko, George A.; Sung, Chih-Jen

2003-01-01

This paper addresses the need to understand the physics and chemistry involved in propellant combustion processes in micro-scale combustors for propulsion systems on micro-spacecraft. These spacecraft are planned to have a mass less than 50 kilograms with attitude control estimated to be in the 10 milli-Newton thrust class. These combustors are anticipated to be manufactured using Micro Electrical Mechanical Systems (MEMS) technology and are expected to have diameters approaching the quenching diameter of the propellants. Combustors of this size are expected to benefit significantly from surface catalysis processes. Miniature flame tube apparatus is chosen for this study because microtubes can be easily fabricated from known catalyst materials and their simplicity in geometry can be used in fundamental simulations to more carefully characterize the measured heat transfer and pressure losses for validation purposes. Experimentally, we investigate the role of catalytically active surfaces within 0.4 and 0.8 mm internal diameter micro-tubes, with special emphases on ignition and extinction processes in fuel rich gaseous hydrogen and gaseous oxygen. Flame thickness and reaction zone thickness calculations predict that the diameters of our test apparatus are below the quenching diameter of the propellants in sub-atmospheric tests. Temperature and pressure rises in resistively heated platinum and palladium micro-tubes are used as an indication of exothermic reactions. Specific data on mass flow versus preheat temperature required to achieve ignition are presented.

The National Ignition Facility modular Kirkpatrick-Baez microscope.

PubMed

Pickworth, L A; Ayers, J; Bell, P; Brejnholt, N F; Buscho, J G; Bradley, D; Decker, T; Hau-Riege, S; Kilkenny, J; McCarville, T; Pardini, T; Vogel, J; Walton, C

2016-11-01

Current two-dimensional X-ray imaging at the National Ignition Facility (NIF) uses time resolved pinhole cameras with ∼10-25 μm pinholes. This method has limitations in the smallest resolvable features that can be imaged with reasonable photon statistics for inertial confinement fusion (ICF) applications. ICF sources have a broadband self-emission spectrum that causes the pinhole images obtained, through thin foil filters, to contain a similarly broadband spectrum complicating the interpretation of structure in the source. In order to study phenomena on the scale of ∼5 μm, such as dopant mix in the ICF capsule, a narrow energy band, higher spatial resolution microscope system with improved signal/noise has been developed using X-ray optics. Utilizing grazing incidence mirrors in a Kirkpatrick-Baez microscope (KBM) configuration [P. Kirkpatrick and A. V. Baez, J. Opt. Soc. Am. 38, 766-774 (1948)], an X-ray microscope has been designed and fielded on NIF with four imaging channels. The KBM has ∼12 × magnification, <8 μm resolution, and higher throughput in comparison to similar pinhole systems. The first KBM mirrors are coated with a multilayer mirror to allow a "narrow band" energy response at 10.2 keV with ΔE ∼ 3 keV. By adjusting the mirror coating only, the energy response can be matched to the future experimental requirements. Several mirror packs have been commissioned and are interchangeable in the diagnostic snout.

Combustion-wave ignition for rocket engines

NASA Technical Reports Server (NTRS)

Liou, Larry C.

1992-01-01

The combustion wave ignition concept was experimentally studied in order to verify its suitability for application in baffled sections of a large booster engine combustion chamber. Gaseous oxygen/gaseous methane (GOX/GH4) and gaseous oxygen/gaseous hydrogen (GOX/GH2) propellant combinations were evaluated in a subscale combustion wave ignition system. The system included four element tubes capable of carrying ignition energy simultaneously to four locations, simulating four baffled sections. Also, direct ignition of a simulated Main Combustion Chamber (MCC) was performed. Tests were conducted over a range of mixture ratios and tube geometries. Ignition was consistently attained over a wide range of mixture ratios. And at every ignition, the flame propagated through all four element tubes. For GOX/GH4, the ignition system ignited the MCC flow at mixture ratios from 2 to 10 and for GOX/GH2 the ratios is from 2 to 13. The ignition timing was found to be rapid and uniform. The total ignition delay when using the MCC was under 11 ms, with the tube-to-tube, as well as the run-to-run, variation under 1 ms. Tube geometries were found to have negligible effect on the ignition outcome and timing.

Development of Cryogenic Engine for GSLV MkIII: Technological Challenges

NASA Astrophysics Data System (ADS)

Praveen, RS; Jayan, N.; Bijukumar, KS; Jayaprakash, J.; Narayanan, V.; Ayyappan, G.

2017-02-01

Cryogenic engine capable of delivering 200 kN thrust is being developed for the first time in the country by ISRO for powering the upper stage of GSLV Mk-III, the next generation launch vehicle of ISRO capable of launching four tonne class satellites to Geo-synchronous Transfer Orbit(GTO). Development of this engine started a decade ago when various sub-systems development and testing were taken up. Starting with injector element development, the design, realization and testing of the major sub-systems viz the gas generator, turbopumps, start-up system and thrust chamber have been successfully done in a phased manner before conducting a series of developmental tests in the integrated engine mode. Apart from the major sub-systems, many critical components like the igniter, control components etc were independently developed and qualified. During the development program many challenges were faced in almost all areas of propulsion engineering. Systems engineering of the engine was another key challenge in the realization. This paper gives an outlook on various technological challenges faced in the key areas related to the engine development, insight to the solutions and measures taken to overcome the challenges.

Indirect drive ignition at the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meezan, N. B.; Edwards, M. J.; Hurricane, O. A.

This article reviews scientific results from the pursuit of indirect drive ignition on the National Ignition Facility (NIF) and describes the program's forward looking research directions. In indirect drive on the NIF, laser beams heat an x-ray enclosure called a hohlraum that surrounds a spherical pellet. X-ray radiation ablates the surface of the pellet, imploding a thin shell of deuterium/tritium (DT) that must accelerate to high velocity (v > 350 km s -1) and compress by a factor of several thousand. Since 2009, substantial progress has been made in understanding the major challenges to ignition: Rayleigh Taylor (RT) instability seededmore » by target imperfections; and low-mode asymmetries in the hohlraum x-ray drive, exacerbated by laser-plasma instabilities (LPI). Requirements on velocity, symmetry, and compression have been demonstrated separately on the NIF but have not been achieved simultaneously. We now know that the RT instability, seeded mainly by the capsule support tent, severely degraded DT implosions from 2009–2012. Experiments using a 'high-foot' drive with demonstrated lower RT growth improved the thermonuclear yield by a factor of 10, resulting in yield amplification due to alpha particle heating by more than a factor of 2. However, large time dependent drive asymmetry in the LPI-dominated hohlraums remains unchanged, preventing further improvements. High fidelity 3D hydrodynamic calculations explain these results. In conclusion, future research efforts focus on improved capsule mounting techniques and on hohlraums with little LPI and controllable symmetry. In parallel, we are pursuing improvements to the basic physics models used in the design codes through focused physics experiments.« less

Indirect drive ignition at the National Ignition Facility

DOE PAGES

Meezan, N. B.; Edwards, M. J.; Hurricane, O. A.; ...

2016-10-27

This article reviews scientific results from the pursuit of indirect drive ignition on the National Ignition Facility (NIF) and describes the program's forward looking research directions. In indirect drive on the NIF, laser beams heat an x-ray enclosure called a hohlraum that surrounds a spherical pellet. X-ray radiation ablates the surface of the pellet, imploding a thin shell of deuterium/tritium (DT) that must accelerate to high velocity (v > 350 km s -1) and compress by a factor of several thousand. Since 2009, substantial progress has been made in understanding the major challenges to ignition: Rayleigh Taylor (RT) instability seededmore » by target imperfections; and low-mode asymmetries in the hohlraum x-ray drive, exacerbated by laser-plasma instabilities (LPI). Requirements on velocity, symmetry, and compression have been demonstrated separately on the NIF but have not been achieved simultaneously. We now know that the RT instability, seeded mainly by the capsule support tent, severely degraded DT implosions from 2009–2012. Experiments using a 'high-foot' drive with demonstrated lower RT growth improved the thermonuclear yield by a factor of 10, resulting in yield amplification due to alpha particle heating by more than a factor of 2. However, large time dependent drive asymmetry in the LPI-dominated hohlraums remains unchanged, preventing further improvements. High fidelity 3D hydrodynamic calculations explain these results. In conclusion, future research efforts focus on improved capsule mounting techniques and on hohlraums with little LPI and controllable symmetry. In parallel, we are pursuing improvements to the basic physics models used in the design codes through focused physics experiments.« less

Analysis of the National Ignition Facility Ignition Hohlraum Energetics Experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Town, R J; Rosen, M D; Michel, P A

2010-11-22

A series of forty experiments on the National Ignition Facility (NIF) [E. I. Moses et al., Phys. Plasmas 16, 041006 (2009)] to study energy balance and implosion symmetry in reduced- and full-scale ignition hohlraums was shot at energies up to 1.3 MJ. This paper reports the findings of the analysis of the ensemble of experimental data obtained that has produced an improved model for simulating ignition hohlraums. Last year the first observation in a NIF hohlraum of energy transfer between cones of beams as a function of wavelength shift between those cones was reported [P. Michel, et al, Phys ofmore » Plasmas, 17, 056305, (2010)]. Detailed analysis of hohlraum wall emission as measured through the laser entrance hole (LEH) has allowed the amount of energy transferred versus wavelength shift to be quantified. The change in outer beam brightness is found to be quantitatively consistent with LASNEX [G. B. Zimmerman and W. L. Kruer, Comments Plasma Phys. Control. Fusion 2, 51 (1975)] simulations using the predicted energy transfer when possible saturation of the plasma wave mediating the transfer is included. The effect of the predicted energy transfer on implosion symmetry is also found to be in good agreement with gated x-ray framing camera images. Hohlraum energy balance, as measured by x-ray power escaping the LEH, is quantitatively consistent with revised estimates of backscatter and incident laser energy combined with a more rigorous non-local-thermodynamic-equilibrium atomic physics model with greater emissivity than the simpler average-atom model used in the original design of NIF targets.« less

YALINA facility a sub-critical Accelerator- Driven System (ADS) for nuclear energy research facility description and an overview of the research program (1997-2008).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gohar, Y.; Smith, D. L.; Nuclear Engineering Division

2010-04-28

The YALINA facility is a zero-power, sub-critical assembly driven by a conventional neutron generator. It was conceived, constructed, and put into operation at the Radiation Physics and Chemistry Problems Institute of the National Academy of Sciences of Belarus located in Minsk-Sosny, Belarus. This facility was conceived for the purpose of investigating the static and dynamic neutronics properties of accelerator driven sub-critical systems, and to serve as a neutron source for investigating the properties of nuclear reactions, in particular transmutation reactions involving minor-actinide nuclei. This report provides a detailed description of this facility and documents the progress of research carried outmore » there during a period of approximately a decade since the facility was conceived and built until the end of 2008. During its history of development and operation to date (1997-2008), the YALINA facility has hosted several foreign groups that worked with the resident staff as collaborators. The participation of Argonne National Laboratory in the YALINA research programs commenced in 2005. For obvious reasons, special emphasis is placed in this report on the work at YALINA facility that has involved Argonne's participation. Attention is given here to the experimental program at YALINA facility as well as to analytical investigations aimed at validating codes and computational procedures and at providing a better understanding of the physics and operational behavior of the YALINA facility in particular, and ADS systems in general, during the period 1997-2008.« less

Overview of the National Ignition Campaign (NIC)

NASA Astrophysics Data System (ADS)

Moses, Edward

2010-11-01

The 192-beam National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) is now operational. NIF has conducted 192-beam implosion experiments with energies as high as 1.2 MJ and has also demonstrated the unprecedented energy and pulse shaping control required for ignition experiments. The successful commissioning of the NIF laser is the first step in demonstrating inertial confinement fusion (ICF) ignition in the laboratory. The NIF ignition program is executed via the National Ignition Campaign (NIC)---a partnership between Los Alamos National Laboratory, Lawrence Berkeley Laboratory, LLNL, General Atomics, the University of Rochester Laboratory for Laser Energetics, Sandia National Laboratories, the Massachusetts Institute of Technology, and other national and international partners. The NIC relies on a novel integrated experimental and computational program to tune the target to the conditions required for indirect-drive ignition. This approach breaks the tuning process into four phases. The first two phases involve tuning of the hohlraum and capsule to produce the correct radiation drive, symmetry, and shock timing conditions. The third phase consists of layered cryogenic implosions conducted with a 50%/49%/1% mixture of tritium, hydrogen, and deuterium (THD) respectively. The reduced yield from these THD targets allows the full diagnostic suite to be employed and the presence of the required temperature and fuel areal density to be verified. The final step is DT ignition implosions with expected gains of 10-20. DT ignition experiments will be conducted with Elaser ˜1.2 MJ. Laser energies of 1.8 MJ should be available for subsequent experiments. This talk will review the multi-phase tuning approach to the ignition effort, including the physics issues associated with the various steps, and current and future plans for the NIF ignition program.

[Exposure to electrocution by automotive ignition system in the work environment of car service employees].

PubMed

Fryśkowski, Bernard; Swiatek-Fryśkowska, Dorota

2014-01-01

Automotive ignition system diagnostic procedures involve a specific kind of action due to the presence of high voltage pulses rated of roughly several dozen kilovolts. Therefore, the repairers employed at car service coming into direct contact with electrical equipment of ignition systems are exposed to risk of electric shock. Typically, the electric discharge energy of automotive ignition systems is not high enough to cause fibrillation due to the electric effect on the heart. Nevertheless, there are drivers and car service employees who use electronic cardiac pacemakers susceptible to high voltage pulses. The influence of high-voltage ignition systems on the human body, especially in case of electric injury, has not been comprehensively elucidated. Therefore, relatively few scientific papers address this problem. The aim of this paper is to consider the electrical injury danger from automotive ignition systems, especially in people suffering from cardiac diseases. Some examples of the methods to reduce electric shock probability during diagnostic procedures of spark-ignition combustion engines are presented and discussed.

An assessment of the use of antimisting fuel in turbofan engines

NASA Technical Reports Server (NTRS)

Fiorentino, A. J.; Planell, J. R.

1983-01-01

An evaluation was made on the effects of using antimisting kerosene (AMK) on the performance of the components from the fuel system and the combustor of current in service JT8D aircraft engines. The objectives were to identify if there were any problems associated with using antimisting kerosene and to determine the extent of shearing or degradation required to allow the engine components to achieve satisfactory operation. The program consisted of a literature survey and a test program which evaluated the antimisting kerosene fuel in laboratory and bench component testing, and assessed the performance of the combustor in a high pressure facility and in an altitude relight/cold ignition facility.

Signal and background considerations for the MRSt on the National Ignition Facility (NIF)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wink, C. W., E-mail: cwink@mit.edu; Frenje, J. A.; Gatu Johnson, M.

2016-11-15

A Magnetic Recoil Spectrometer (MRSt) has been conceptually designed for time-resolved measurements of the neutron spectrum at the National Ignition Facility. Using the MRSt, the goals are to measure the time-evolution of the spectrum with a time resolution of ∼20-ps and absolute accuracy better than 5%. To meet these goals, a detailed understanding and optimization of the signal and background characteristics are required. Through ion-optics, MCNP simulations, and detector-response calculations, it is demonstrated that the goals and a signal-to background >5–10 for the down-scattered neutron measurement are met if the background, consisting of ambient neutrons and gammas, at the MRStmore » is reduced 50–100 times.« less

First Observation of Cross-Beam Energy Transfer Mitigation for Direct-Drive Inertial Confinement Fusion Implosions Using Wavelength Detuning at the National Ignition Facility.

PubMed

Marozas, J A; Hohenberger, M; Rosenberg, M J; Turnbull, D; Collins, T J B; Radha, P B; McKenty, P W; Zuegel, J D; Marshall, F J; Regan, S P; Sangster, T C; Seka, W; Campbell, E M; Goncharov, V N; Bowers, M W; Di Nicola, J-M G; Erbert, G; MacGowan, B J; Pelz, L J; Yang, S T

2018-02-23

Cross-beam energy transfer (CBET) results from two-beam energy exchange via seeded stimulated Brillouin scattering, which detrimentally reduces ablation pressure and implosion velocity in direct-drive inertial confinement fusion. Mitigating CBET is demonstrated for the first time in inertial-confinement implosions at the National Ignition Facility by detuning the laser-source wavelengths (±2.3  Å UV) of the interacting beams. We show that, in polar direct-drive, wavelength detuning increases the equatorial region velocity experimentally by 16% and alters the in-flight shell morphology. These experimental observations are consistent with design predictions of radiation-hydrodynamic simulations that indicate a 10% increase in the average ablation pressure.

First results of radiation-driven, layered deuterium-tritium implosions with a 3-shock adiabat-shaped drive at the National Ignition Facility

DOE PAGES

Smalyuk, V. A.; Robey, H. F.; Döppner, T.; ...

2015-08-27

Radiation-driven, layered deuterium-tritium plastic capsule implosions were carried out using a new, 3-shock “adiabat-shaped” drive on the National Ignition Facility. The purpose of adiabat shaping is to use a stronger first shock, reducing hydrodynamic instability growth in the ablator. The shock can decay before reaching the deuterium-tritium fuel leaving it on a low adiabat and allowing higher fuel compression. The fuel areal density was improved by ~25% with this new drive compared to similar “high-foot” implosions, while neutron yield was improved by more than 4 times, compared to “low-foot” implosions driven at the same compression and implosion velocity.

View Factor and Radiation-Hydrodynamic Simulations of Gas-Filled Outer-Quad-Only Hohlraums at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Young, Christopher; Meezan, Nathan; Landen, Otto

2017-10-01

A cylindrical National Ignition Facility hohlraum irradiated exclusively by NOVA-like outer quads (44 .5° and 50° beams) is proposed to minimize laser plasma interaction (LPI) losses and avoid problems with propagating the inner (23 .5° and 30°) beams. Symmetry and drive are controlled by shortening the hohlraum, using a smaller laser entrance hole (LEH), beam phasing the 44 .5° and 50° beams, and correcting the remaining P4 asymmetry with a capsule shim. Ensembles of time-resolved view factor simulations help narrow the design space of the new configuration, with fine tuning provided by the radiation-hydrodynamic code HYDRA. Prepared by LLNL under Contract DE-AC52-07NA27344.

High-density carbon capsule experiments on the national ignition facility

DOE PAGES

Ross, J. S.; Ho, D.; Milovich, J.; ...

2015-02-25

Indirect-drive implosions with a high-density carbon (HDC) capsule were conducted on the National Ignition Facility (NIF) to test HDC properties as an ablator material for inertial confinement fusion. In this study, a series of five experiments were completed with 76-μm-thick HDC capsules using a four-shock laser pulse optimized for HDC. The pulse delivered a total energy of 1.3 MJ with a peak power of 360 TW. The experiment demonstrated good laser to target coupling (~90 %) and excellent nuclear performance. Lastly, a deuterium and tritium gas-filled HDC capsule implosion produced a neutron yield of 1.6×10 15 ± 3×10 13, amore » yield over simulated in one dimension of 70%.« less

Signal and background considerations for the MRSt on the National Ignition Facility (NIF)

DOE PAGES

Wink, C. W.; Frenje, J. A.; Hilsabeck, T. J.; ...

2016-08-03

A Magnetic Recoil Spectrometer (MRSt) has been conceptually designed for time-resolved measurements of the neutron spectrum at the National Ignition Facility. Using the MRSt, the goals are to measure the time-evolution of the spectrum with a time resolution of ~20-ps and absolute accuracy better than 5%. To meet these goals, a detailed understanding and optimization of the signal and background characteristics are required. Through ion-optics, MCNP simulations, and detector-response calculations, we demonstrate that the goals and a signal-to background >5-10 for the down-scattered neutron measurement are met if the background, consisting of ambient neutrons and gammas, at the MRSt ismore » reduced 50-100 times.« less

First Iron Opacity Experiments on the National Ignition Facility

NASA Astrophysics Data System (ADS)

Perry, Theodore; Dodd, Evan; Cardenas, Tana; Devolder, Barbara; Flippo, Kirk; Johns, Heather; Kline, John; Sherrill, Manolo; Urbatsch, Todd; Heeter, Robert; Ahmed, Maryum; Emig, James; Iglesias, Carlos; Liedahl, Duane; London, Richard; Martin, Madison; Schneider, Marilyn; Thompson, Nathaniel; Wilson, Brian; Opachich, Yekaterina; King, James; Huffman, Eric; Knight, Russel; Bailey, James; Rochau, Gregory

2017-10-01

Iron opacity experiments on the Sandia National Laboratories Z machine have shown up to factors of two discrepancies between theory and experiment. To help resolve these discrepancies an experimental platform for doing comparable opacity experiments is being developed on the National Ignition Facility (NIF). Initial iron data has been taken at a temperature of 150 eV and an electron density of 6x1021/cm3, but higher temperatures and densities will be required to address the discrepancies that have been observed in the Z experiments. The plans to go to higher temperatures and densities and how to deal with current issues with instrumental backgrounds will be discussed. Performed under the auspices of USDOE LANL Contract DE-AC52-06NA25396.

A recoverable gas-cell diagnostic for the National Ignition Facility.

PubMed

Ratkiewicz, A; Berzak Hopkins, L; Bleuel, D L; Bernstein, L A; van Bibber, K; Cassata, W S; Goldblum, B L; Siem, S; Velsko, C A; Wiedeking, M; Yeamans, C B

2016-11-01

The high-fluence neutron spectrum produced by the National Ignition Facility (NIF) provides an opportunity to measure the activation of materials by fast-spectrum neutrons. A new large-volume gas-cell diagnostic has been designed and qualified to measure the activation of gaseous substances at the NIF. This in-chamber diagnostic is recoverable, reusable and has been successfully fielded. Data from the qualification of the diagnostic have been used to benchmark an Monte Carlo N-Particle Transport Code simulation describing the downscattered neutron spectrum seen by the gas cell. We present early results from the use of this diagnostic to measure the activation of nat Xe and discuss future work to study the strength of interactions between plasma and nuclei.

First Observation of Cross-Beam Energy Transfer Mitigation for Direct-Drive Inertial Confinement Fusion Implosions Using Wavelength Detuning at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Marozas, J. A.; Hohenberger, M.; Rosenberg, M. J.; Turnbull, D.; Collins, T. J. B.; Radha, P. B.; McKenty, P. W.; Zuegel, J. D.; Marshall, F. J.; Regan, S. P.; Sangster, T. C.; Seka, W.; Campbell, E. M.; Goncharov, V. N.; Bowers, M. W.; Di Nicola, J.-M. G.; Erbert, G.; MacGowan, B. J.; Pelz, L. J.; Yang, S. T.

2018-02-01

Cross-beam energy transfer (CBET) results from two-beam energy exchange via seeded stimulated Brillouin scattering, which detrimentally reduces ablation pressure and implosion velocity in direct-drive inertial confinement fusion. Mitigating CBET is demonstrated for the first time in inertial-confinement implosions at the National Ignition Facility by detuning the laser-source wavelengths (±2.3 Å UV) of the interacting beams. We show that, in polar direct-drive, wavelength detuning increases the equatorial region velocity experimentally by 16% and alters the in-flight shell morphology. These experimental observations are consistent with design predictions of radiation-hydrodynamic simulations that indicate a 10% increase in the average ablation pressure.

Particle damage sources for fused silica optics and their mitigation on high energy laser systems.

PubMed

Bude, J; Carr, C W; Miller, P E; Parham, T; Whitman, P; Monticelli, M; Raman, R; Cross, D; Welday, B; Ravizza, F; Suratwala, T; Davis, J; Fischer, M; Hawley, R; Lee, H; Matthews, M; Norton, M; Nostrand, M; VanBlarcom, D; Sommer, S

2017-05-15

High energy laser systems are ultimately limited by laser-induced damage to their critical components. This is especially true of damage to critical fused silica optics, which grows rapidly upon exposure to additional laser pulses. Much progress has been made in eliminating damage precursors in as-processed fused silica optics (the advanced mitigation process, AMP3), and very high damage resistance has been demonstrated in laboratory studies. However, the full potential of these improvements has not yet been realized in actual laser systems. In this work, we explore the importance of additional damage sources-in particular, particle contamination-for fused silica optics fielded in a high-performance laser environment, the National Ignition Facility (NIF) laser system. We demonstrate that the most dangerous sources of particle contamination in a system-level environment are laser-driven particle sources. In the specific case of the NIF laser, we have identified the two important particle sources which account for nearly all the damage observed on AMP3 optics during full laser operation and present mitigations for these particle sources. Finally, with the elimination of these laser-driven particle sources, we demonstrate essentially damage free operation of AMP3 fused silica for ten large optics (a total of 12,000 cm 2 of beam area) for shots from 8.6 J/cm 2 to 9.5 J/cm 2 of 351 nm light (3 ns Gaussian pulse shapes). Potentially many other pulsed high energy laser systems have similar particle sources, and given the insight provided by this study, their identification and elimination should be possible. The mitigations demonstrated here are currently being employed for all large UV silica optics on the National Ignition Facility.

Thermal ignition combustion system

DOEpatents

Kamo, R.; Kakwani, R.M.; Valdmanis, E.; Woods, M.E.

1988-04-19

The thermal ignition combustion system comprises means for providing walls defining an ignition chamber, the walls being made of a material having a thermal conductivity greater than 20 W/m C and a specific heat greater than 480 J/kg C with the ignition chamber being in constant communication with the main combustion chamber, means for maintaining the temperature of the walls above a threshold temperature capable of causing ignition of a fuel, and means for conducting fuel to the ignition chamber. 8 figs.

Thermal ignition combustion system

DOEpatents

Kamo, Roy; Kakwani, Ramesh M.; Valdmanis, Edgars; Woods, Melvins E.

1988-01-01

The thermal ignition combustion system comprises means for providing walls defining an ignition chamber, the walls being made of a material having a thermal conductivity greater than 20 W/m.degree. C. and a specific heat greater than 480 J/kg.degree. C. with the ignition chamber being in constant communication with the main combustion chamber, means for maintaining the temperature of the walls above a threshold temperature capable of causing ignition of a fuel, and means for conducting fuel to the ignition chamber.

Oxygen Handling and Cooling Options in High Temperature Electrolysis Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manohar S. Sohal; J. Stephen Herring

2008-07-01

Idaho National Laboratory is working on a project to generate hydrogen by high temperature electrolysis (HTE). In such an HTE system, safety precautions need to be taken to handle high temperature oxygen at ~830°C. This report is aimed at addressing oxygen handling in a HTE plant.. Though oxygen itself is not flammable, most engineering material, including many gases and liquids, will burn in the presence of oxygen under some favorable physicochemical conditions. At present, an absolute set of rules does not exist that can cover all aspects of oxygen system design, material selection, and operating practices to avoid subtle hazardsmore » related to oxygen. Because most materials, including metals, will burn in an oxygen-enriched environment, hazards are always present when using oxygen. Most materials will ignite in an oxygen-enriched environment at a temperature lower than that in air, and once ignited, combustion rates are greater in the oxygen-enriched environment. Even many metals, if ignited, burn violently in an oxygen-enriched environment. However, these hazards do not preclude the operations and systems involving oxygen. Oxygen can be safely handled and used if all the materials in a system are not flammable in the end-use environment or if ignition sources are identified and controlled. In fact, the incidence of oxygen system fires is reported to be low with a probability of about one in a million. This report is a practical guideline and tutorial for the safe operation and handling of gaseous oxygen in high temperature electrolysis system. The intent is to provide safe, practical guidance that permits the accomplishment of experimental operations at INL, while being restrictive enough to prevent personnel endangerment and to provide reasonable facility protection. Adequate guidelines are provided to govern various aspects of oxygen handling associated with high temperature electrolysis system to generate hydrogen. The intent here is to present acceptable oxygen standards and practices for minimum safety requirements. A summary of operational hazards, along with oxygen safety and emergency procedures, are provided.« less

Ignitability test method and apparatus

NASA Technical Reports Server (NTRS)

Bement, Laurence J. (Inventor); Bailey, James W. (Inventor); Schimmel, Morry L. (Inventor)

1989-01-01

An apparatus for testing ignitability of an initiator includes a body with a central cavity, initiator holder for holding the initiator over the central cavity of the body, an ignition material holder disposed in the central cavity of the body and a cavity facing the initiator holder which receives a measured quantity of ignition material to be ignited by the initiator and a chamber in communication with the cavity of the ignition material holder and the central cavity of the body. A measuring system for analyzing pressure characteristics is generated by ignition material by the initiator. The measuring system includes at least one transducer coupled to an oscillograph for recording pressure traces generated by ignition.

Demonstration of High Performance in Layered Deuterium-Tritium Capsule Implosions in Uranium Hohlraums at the National Ignition Facility.

PubMed

Döppner, T; Callahan, D A; Hurricane, O A; Hinkel, D E; Ma, T; Park, H-S; Berzak Hopkins, L F; Casey, D T; Celliers, P; Dewald, E L; Dittrich, T R; Haan, S W; Kritcher, A L; MacPhee, A; Le Pape, S; Pak, A; Patel, P K; Springer, P T; Salmonson, J D; Tommasini, R; Benedetti, L R; Bond, E; Bradley, D K; Caggiano, J; Church, J; Dixit, S; Edgell, D; Edwards, M J; Fittinghoff, D N; Frenje, J; Gatu Johnson, M; Grim, G; Hatarik, R; Havre, M; Herrmann, H; Izumi, N; Khan, S F; Kline, J L; Knauer, J; Kyrala, G A; Landen, O L; Merrill, F E; Moody, J; Moore, A S; Nikroo, A; Ralph, J E; Remington, B A; Robey, H F; Sayre, D; Schneider, M; Streckert, H; Town, R; Turnbull, D; Volegov, P L; Wan, A; Widmann, K; Wilde, C H; Yeamans, C

2015-07-31

We report on the first layered deuterium-tritium (DT) capsule implosions indirectly driven by a "high-foot" laser pulse that were fielded in depleted uranium hohlraums at the National Ignition Facility. Recently, high-foot implosions have demonstrated improved resistance to ablation-front Rayleigh-Taylor instability induced mixing of ablator material into the DT hot spot [Hurricane et al., Nature (London) 506, 343 (2014)]. Uranium hohlraums provide a higher albedo and thus an increased drive equivalent to an additional 25 TW laser power at the peak of the drive compared to standard gold hohlraums leading to higher implosion velocity. Additionally, we observe an improved hot-spot shape closer to round which indicates enhanced drive from the waist. In contrast to findings in the National Ignition Campaign, now all of our highest performing experiments have been done in uranium hohlraums and achieved total yields approaching 10^{16} neutrons where more than 50% of the yield was due to additional heating of alpha particles stopping in the DT fuel.

Development of Modeling Capabilities for Launch Pad Acoustics and Ignition Transient Environment Prediction

NASA Technical Reports Server (NTRS)

West, Jeff; Strutzenberg, Louise L.; Putnam, Gabriel C.; Liever, Peter A.; Williams, Brandon R.

2012-01-01

This paper presents development efforts to establish modeling capabilities for launch vehicle liftoff acoustics and ignition transient environment predictions. Peak acoustic loads experienced by the launch vehicle occur during liftoff with strong interaction between the vehicle and the launch facility. Acoustic prediction engineering tools based on empirical models are of limited value in efforts to proactively design and optimize launch vehicles and launch facility configurations for liftoff acoustics. Modeling approaches are needed that capture the important details of the plume flow environment including the ignition transient, identify the noise generation sources, and allow assessment of the effects of launch pad geometric details and acoustic mitigation measures such as water injection. This paper presents a status of the CFD tools developed by the MSFC Fluid Dynamics Branch featuring advanced multi-physics modeling capabilities developed towards this goal. Validation and application examples are presented along with an overview of application in the prediction of liftoff environments and the design of targeted mitigation measures such as launch pad configuration and sound suppression water placement.

Hydro-scaling of DT implosions on the National Ignition Facility

NASA Astrophysics Data System (ADS)

Patel, Pravesh; Spears, Brian; Clark, Dan

2017-10-01

Recent implosion experiments on the National Ignition Facility (NIF) exceed 50 kJ in fusion yield and exhibit yield amplifications of >2.5-3x due to alpha-particle self-heating of the hot-spot. Two methods to increase the yield are (i) to improve the implosion quality, or stagnation pressure, at fixed target scale (by increasing implosion velocity, reducing 3D effects, etc.), and (ii) to hydrodynamically scale the capsule and absorbed energy. In the latter case the stagnation pressure remains constant, but the yield-in the absence of alpha-heating-increases as Y S 4 . 5 , where the capsule radius is increased by S, and the absorbed energy by S3 . With alpha-heating the increase with scale is considerably stronger. We present projections in the performance of current DT experiments, and the extrapolations to ignition, based on applying hydro-scaling theory and accounting for the effect of alpha-heating. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Demonstration of High Performance in Layered Deuterium-Tritium Capsule Implosions in Uranium Hohlraums at the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Döppner, T.; Callahan, D. A.; Hurricane, O. A.

We report on the first layered deuterium-tritium (DT) capsule implosions indirectly driven by a “highfoot” laser pulse that were fielded in depleted uranium hohlraums at the National Ignition Facility. Recently, high-foot implosions have demonstrated improved resistance to ablation-front Rayleigh-Taylor instability induced mixing of ablator material into the DT hot spot [Hurricane et al., Nature (London) 506, 343 (2014)]. Uranium hohlraums provide a higher albedo and thus an increased drive equivalent to an additional 25 TW laser power at the peak of the drive compared to standard gold hohlraums leading to higher implosion velocity. Additionally, we observe an improved hot-spot shapemore » closer to round which indicates enhanced drive from the waist. In contrast to findings in the National Ignition Campaign, now all of our highest performing experiments have been done in uranium hohlraums and achieved total yields approaching 10 16 neutrons where more than 50% of the yield was due to additional heating of alpha particles stopping in the DT fuel.« less

Demonstration of High Performance in Layered Deuterium-Tritium Capsule Implosions in Uranium Hohlraums at the National Ignition Facility

DOE PAGES

Döppner, T.; Callahan, D. A.; Hurricane, O. A.; ...

2015-07-28

We report on the first layered deuterium-tritium (DT) capsule implosions indirectly driven by a “highfoot” laser pulse that were fielded in depleted uranium hohlraums at the National Ignition Facility. Recently, high-foot implosions have demonstrated improved resistance to ablation-front Rayleigh-Taylor instability induced mixing of ablator material into the DT hot spot [Hurricane et al., Nature (London) 506, 343 (2014)]. Uranium hohlraums provide a higher albedo and thus an increased drive equivalent to an additional 25 TW laser power at the peak of the drive compared to standard gold hohlraums leading to higher implosion velocity. Additionally, we observe an improved hot-spot shapemore » closer to round which indicates enhanced drive from the waist. In contrast to findings in the National Ignition Campaign, now all of our highest performing experiments have been done in uranium hohlraums and achieved total yields approaching 10 16 neutrons where more than 50% of the yield was due to additional heating of alpha particles stopping in the DT fuel.« less

Experimental Investigation of Laser-sustained Plasma in Supersonic Argon Flow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sperber, David; Eckel, Hans-Albert; Moessinger, Peter

Laser-induced energy deposition is widely discussed as a flow control technique in supersonic transportation. In case of thermal laser-plasma upstream of a blunt body, a substantial adaptation of shock wave geometry and magnitude of wave drag is predicted. Related to the research on laser supported detonation, the paper describes the implementation of laser-sustained plasma in a supersonic Argon jet. The stable plasma state is generated by the intersection of a Q-switched Nd:YAG-laser and a continuous wave CO{sub 2}-laser beams, for ignition and maintenance of the plasma respectively. A miniature supersonic Ludwieg tube test facility generates a supersonic jet at velocitiesmore » of Mach 2.1. Modifications of the flow and plasma conditions are investigated and characterized by Schlieren flow visualisation, laser energy transmission and plasma radiation measurements. The results include the discussions of the flow field as well as the required laser and gas parameters.« less

Hot-spot mix in ignition-scale inertial confinement fusion targets.

PubMed

Regan, S P; Epstein, R; Hammel, B A; Suter, L J; Scott, H A; Barrios, M A; Bradley, D K; Callahan, D A; Cerjan, C; Collins, G W; Dixit, S N; Döppner, T; Edwards, M J; Farley, D R; Fournier, K B; Glenn, S; Glenzer, S H; Golovkin, I E; Haan, S W; Hamza, A; Hicks, D G; Izumi, N; Jones, O S; Kilkenny, J D; Kline, J L; Kyrala, G A; Landen, O L; Ma, T; MacFarlane, J J; MacKinnon, A J; Mancini, R C; McCrory, R L; Meezan, N B; Meyerhofer, D D; Nikroo, A; Park, H-S; Ralph, J; Remington, B A; Sangster, T C; Smalyuk, V A; Springer, P T; Town, R P J

2013-07-26

Mixing of plastic ablator material, doped with Cu and Ge dopants, deep into the hot spot of ignition-scale inertial confinement fusion implosions by hydrodynamic instabilities is diagnosed with x-ray spectroscopy on the National Ignition Facility. The amount of hot-spot mix mass is determined from the absolute brightness of the emergent Cu and Ge K-shell emission. The Cu and Ge dopants placed at different radial locations in the plastic ablator show the ablation-front hydrodynamic instability is primarily responsible for hot-spot mix. Low neutron yields and hot-spot mix mass between 34(-13,+50)  ng and 4000(-2970,+17 160)  ng are observed.

Capsule Ablator Inflight Performance Measurements Via Streaked Radiography Of ICF Implosions On The NIF*

NASA Astrophysics Data System (ADS)

Dewald, E. L.; Tommasini, R.; Mackinnon, A.; MacPhee, A.; Meezan, N.; Olson, R.; Hicks, D.; LePape, S.; Izumi, N.; Fournier, K.; Barrios, M. A.; Ross, S.; Pak, A.; Döppner, T.; Kalantar, D.; Opachich, K.; Rygg, R.; Bradley, D.; Bell, P.; Hamza, A.; Dzenitis, B.; Landen, O. L.; MacGowan, B.; LaFortune, K.; Widmayer, C.; Van Wonterghem, B.; Kilkenny, J.; Edwards, M. J.; Atherton, J.; Moses, E. I.

2016-03-01

Streaked 1-dimensional (slit imaging) radiography of 1.1 mm radius capsules in ignition hohlraums was recently introduced on the National Ignition Facility (NIF) and gives an inflight continuous record of capsule ablator implosion velocities, shell thickness and remaining mass in the last 3-5 ns before peak implosion time. The high quality data delivers good accuracy in implosion metrics that meets our requirements for ignition and agrees with recently introduced 2-dimensional pinhole radiography. Calculations match measured trajectory across various capsule designs and laser drives when the peak laser power is reduced by 20%. Furthermore, calculations matching measured trajectories give also good agreement in ablator shell thickness and remaining mass.

A simple method to prevent hard X-ray-induced preheating effects inside the cone tip in indirect-drive fast ignition implosions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Dongxiao; Shan, Lianqiang; Zhou, Weimin

During fast-ignition implosions, preheating of inside the cone tip caused by hard X-rays can strongly affect the generation and transport of hot electrons in the cone. Although indirect-drive implosions have a higher implosion symmetry, they cause stronger preheating effects than direct-drive implosions. To control the preheating of the cone tip, we propose the use of indirect-drive fast-ignition targets with thicker tips. Experiments carried out at the ShenGuang-III prototype laser facility confirmed that thicker tips are effective for controlling preheating. Moreover, these results were consistent with those of 1D radiation hydrodynamic simulations.

Hot-spot mix in ignition-scale inertial confinement fusion targets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Regan, S. P.; Epstein, R.; Hammel, B. A.

Mixing of plastic ablator material, doped with Cu and Ge dopants, deep into the hot spot of ignition-scale inertial confinement fusion implosions by hydrodynamic instabilities is diagnosed with x-ray spectroscopy on the National Ignition Facility. The amount of hot-spot mix mass is determined from the absolute brightness of the emergent Cu and Ge K-shell emission. The Cu and Ge dopants placed at different radial locations in the plastic ablator show the ablation-front hydrodynamic instability is primarily responsible for hot-spot mix. As a result, low neutron yields and hot-spot mix mass between 34(–13,+50) ng and 4000(–2970,+17 160) ng are observed.

Hot-spot mix in ignition-scale inertial confinement fusion targets

DOE PAGES

Regan, S. P.; Epstein, R.; Hammel, B. A.; ...

2013-07-22

Mixing of plastic ablator material, doped with Cu and Ge dopants, deep into the hot spot of ignition-scale inertial confinement fusion implosions by hydrodynamic instabilities is diagnosed with x-ray spectroscopy on the National Ignition Facility. The amount of hot-spot mix mass is determined from the absolute brightness of the emergent Cu and Ge K-shell emission. The Cu and Ge dopants placed at different radial locations in the plastic ablator show the ablation-front hydrodynamic instability is primarily responsible for hot-spot mix. As a result, low neutron yields and hot-spot mix mass between 34(–13,+50) ng and 4000(–2970,+17 160) ng are observed.

Repetitive laser ignition by optical breakdown of a LOX/H2 rocket combustion chamber with multi-injector head configuration

NASA Astrophysics Data System (ADS)

Börner, Michael; Manfletti, Chiara; Kroupa, Gerhard; Oschwald, Michael

2017-09-01

This paper reports on the repetitive laser ignition by optical breakdown within an experimental rocket combustion chamber. Ignition was performed by focusing a laser pulse generated by a miniaturized diode-pumped Nd:YAG laser system. The system, which delivers 33.2 mJ in 2.3 ns, was mounted directly to the combustion chamber. The ignition process and flame stabilization was investigated using an optical probe system monitoring the flame attachment across the 15 coaxial injector configuration. 1195 successful ignitions were performed proving the reliability of this laser ignition system and its applicability to the propellant combination LOX/hydrogen at temperatures of T_{{{H}_{ 2} }} = 120-282 K and T_{{{O}_{ 2} }} = 110-281 K.

Ignition improvement by injector arrangement in a multi-fuel combustor for micro gas turbine

NASA Astrophysics Data System (ADS)

Antoshkiv, O.; Poojitganont, T.; Jeansirisomboon, S.; Berg, H. P.

2018-01-01

The novel combustor design also has an impact on the ignitor arrangement. The conventional ignitor system cannot guarantee optimal ignition performance in the usual radial position. The difficult ignitability of gaseous fuels was the main challenge for the ignitor system improvement. One way to improve the ignition performance significantly is a torch ignitor system in which the gaseous fuel is directly mixed with a large amount of the combustor air. To reach this goal, the ignition process was investigated in detail. The micro gas turbine (MGT) ignition was optimised considering three main procedures: torch ignitor operation, burner ignition and flame propagation between the neighbour injectors. A successful final result of the chain of ignition procedures depends on multiple aspects of the combustor design. Performed development work shows an important step towards designing modern high-efficiency low-emission combustors.

Fuelling the palaeoatmospheric oxygen debate: how much atmospheric oxygen is required for ignition and propagation of smouldering fires?

NASA Astrophysics Data System (ADS)

Belcher, Claire M.; Hadden, Rory; McElwain, Jennifer C.; Rein, Guillermo

2010-05-01

Fire is a natural process integral to ecosystems at a wide range of temporal and spatial scales and is a key driver of change in the Earth system. Fire has been a major influence on Earth's systems since the Carboniferous. Whilst, climate is considered the ultimate control on global vegetation, fire is now known to play a key role in determining vegetation structure and composition, such that many of the world's ecosystems can be considered fire-dependant. Products of fire include chars, soots and aromatic hydrocarbon species all of which can be traced in ancient through to modern sediments. Atmospheric oxygen has played a key role in the development of life on Earth, with the rise of oxygen in the Precambrian being closely linked to biological evolution. Variations in the concentration of atmospheric oxygen throughout the Phanerozoic are predicted from models based on geochemical cycling of carbon and sulphur. Such models predict that low atmospheric oxygen concentrations prevailed in the Mesozoic (251-65ma) and have been hypothesised to be the primary driver of at least two of the ‘big five' mass extinction events in the Phanerozoic. Here we assess the levels of atmospheric oxygen required to ignite a fire and infer the likely levels of atmospheric oxygen to support smouldering combustion. Smouldering fire dynamics and its effects on ecosystems are very different from flaming fires. Smouldering fires propagate slowly, are usually low in temperature and represent a flameless form of combustion. These fires creep through organic layers of forest ground and peat lands and are responsible for a large fraction of the total biomass consumed in wildfires globally and are also a major contributor of carbon dioxide to the atmosphere. Once ignited, they can persist for long periods of time (months, years) spreading over very extensive areas of forest and deep into soil. Smouldering fires are therefore, the oldest continuously burning fires on Earth. We have combined expertise from both the Earth science and fire engineering disciplines to develop realistic ignition mechanisms and measurements of fire propagation within different levels of atmospheric oxygen. We present data from experimental burns run in the fully controlled and realistic atmospheric environment of the UCD PÉAC facility. The burns are designed to develop our understanding of ignition of fires in the natural world. We have studied ignition and propagation of fire in peat, a natural and highly flammable substance. Peat samples of approximately 100mm by 100mm in cross section and 50mm in depth were exposed to an ignition source (~100W of electric power) for 30 minutes. Thermocouples were placed throughout the sample to measure temperature changes during the initial 30 minute ignition phase and in order to observe ignition of the peat, intensity of combustion and spread of the smouldering front within the different atmospheric oxygen settings. We show that ignition and propagation of smouldering in peat does not occur below 16% atmospheric oxygen and that smouldering combustion continues for long periods (~4 hours in the size sample used) at 18% atmospheric oxygen and above. This suggests that atmospheric levels above 16% atmospheric are required to allow ignition and propagation of smouldering fires and that frequent occurrences of wildfires might only be expected in the geological past when atmospheric levels were above 18% oxygen. Fires play an important role in Earth's biogeochemical cycles; this work suggests that fire feedbacks into the Earth system would likely have been suppressed during periods of low atmospheric oxygen.

Scaling of Energy Deposition in Fast Ignition Targets

NASA Astrophysics Data System (ADS)

Campbell, R. B.; Welch, Dale

2005-10-01

We examine the scaling to ignition of the energy deposition of laser generated electrons in compressed fast ignition cores. Relevant cores have densities of several hundred g/cm^3, with a few keV initial temperature. As the laser intensities increase approaching ignition systems, on the order of a few 10^21W/cm^2, the hot electron energies expected to approach 100MeV[1]. Most certainly anomalous processes must play a role in the energy transfer, but the exact nature of these processes, as well as a practical way to model them, remain open issues. Traditional PIC explicit methods are limited to low densities on current and anticipated computing platforms, so the study of relevant parameter ranges has received so far little attention. We use LSP[2] to examine a relativistic electron beam (presumed generated from a laser plasma interaction) of legislated energy and angular distribution is injected into a 3D block of compressed DT. Collective effects will determine the stopping, most likely driven by magnetic field filamentation. The scaling of the stopping as a function of block density and temperature, as well as hot electron current and laser intensity is presented. Sub-grid models may be profitably used and degenerate effects included in the solution of this problem. Sandia is operated by Sandia Corporation, for the USDOE. [1] A. Pukhov, et. al., Phys. Plas. 6, p2847 (1999) [2] D. R. Welch et al., Comput. Phys.Commun. 164, p183 (2004).

Experimental and numerical investigation on the ignition and combustion stability in solid fuel ramjet with swirling flow

NASA Astrophysics Data System (ADS)

Musa, Omer; Xiong, Chen; Changsheng, Zhou

2017-08-01

The present article investigates experimentally and numerically the ignition and flame stability of high-density polyethylene solid fuel with incoming swirling air through a solid fuel ramjet (SFRJ). A new design of swirler is proposed and used in this work. Experiments on connected pipes test facility were performed for SFRJ with and without swirl. An in-house code has been developed to simulate unsteady, turbulent, reacting, swirling flow in the SFRJ. Four different swirl intensities are utilized to study experimentally and numerically the effect of swirl number on the transient regression, ignition of the solid fuel in a hot-oxidizing flow and combustion phenomenon in the SFRJ. The results showed that using swirl flow decreases the ignition time delay, recirculation zone length, and the distance between the flame and the wall, meanwhile, increases the residence time, heat transfer, regression rate and mixing degree, thus, improving the combustion efficiency and stability.

Stabilization of high-compression, indirect-drive inertial confinement fusion implosions using a 4-shock adiabat-shaped drive

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacPhee, A. G.; Peterson, J. L.; Casey, D. T.

Hydrodynamic instabilities and poor fuel compression are major factors for capsule performance degradation in ignition experiments on the National Ignition Facility. Using a recently developed laser drive profile with a decaying first shock to tune the ablative Richtmyer-Meshkov (ARM) instability and subsequent in-flight Rayleigh-Taylor growth, we have demonstrated reduced growth compared to the standard ignition pulse whilst maintaining conditions for a low fuel adiabat needed for increased compression. Using in-flight x-ray radiography of pre-machined modulations, the first growth measurements using this new ARM-tuned drive have demonstrated instability growth reduction of ∼4× compared to the original design at a convergence ratiomore » of ∼2. Corresponding simulations give a fuel adiabat of ∼1.6, similar to the original goal and consistent with ignition requirements.« less

Stabilization of high-compression, indirect-drive inertial confinement fusion implosions using a 4-shock adiabat-shaped drive

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacPhee, A. G.; Peterson, J. L.; Casey, D. T.

Hydrodynamic instabilities and poor fuel compression are major factors for capsule performance degradation in ignition experiments on the National Ignition Facility. Using a recently developed laser drive profile with a decaying first shock to tune the ablative Richtmyer-Meshkov (ARM) instability and subsequent in-flight Rayleigh-Taylor growth, we have demonstrated reduced growth compared to the standard ignition pulse whilst maintaining conditions for a low fuel adiabat needed for increased compression. Here, using in-flight x-ray radiography of pre-machined modulations, the first growth measurements using this new ARM-tuned drive have demonstrated instability growth reduction of ~4× compared to the original design at a convergencemore » ratio of ~2. Corresponding simulations give a fuel adiabat of ~1.6, similar to the original goal and consistent with ignition requirements.« less

Stabilization of high-compression, indirect-drive inertial confinement fusion implosions using a 4-shock adiabat-shaped drive

DOE PAGES

MacPhee, A. G.; Peterson, J. L.; Casey, D. T.; ...

2015-08-01

Hydrodynamic instabilities and poor fuel compression are major factors for capsule performance degradation in ignition experiments on the National Ignition Facility. Using a recently developed laser drive profile with a decaying first shock to tune the ablative Richtmyer-Meshkov (ARM) instability and subsequent in-flight Rayleigh-Taylor growth, we have demonstrated reduced growth compared to the standard ignition pulse whilst maintaining conditions for a low fuel adiabat needed for increased compression. Here, using in-flight x-ray radiography of pre-machined modulations, the first growth measurements using this new ARM-tuned drive have demonstrated instability growth reduction of ~4× compared to the original design at a convergencemore » ratio of ~2. Corresponding simulations give a fuel adiabat of ~1.6, similar to the original goal and consistent with ignition requirements.« less

High-density carbon ablator ignition path with low-density gas-filled rugby hohlraum

NASA Astrophysics Data System (ADS)

Amendt, Peter; Ho, Darwin D.; Jones, Ogden S.

2015-04-01

A recent low gas-fill density (0.6 mg/cc 4He) cylindrical hohlraum experiment on the National Ignition Facility has shown high laser-coupling efficiency (>96%), reduced phenomenological laser drive corrections, and improved high-density carbon capsule implosion symmetry [Jones et al., Bull. Am. Phys. Soc. 59(15), 66 (2014)]. In this Letter, an ignition design using a large rugby-shaped hohlraum [Amendt et al., Phys. Plasmas 21, 112703 (2014)] for high energetics efficiency and symmetry control with the same low gas-fill density (0.6 mg/cc 4He) is developed as a potentially robust platform for demonstrating thermonuclear burn. The companion high-density carbon capsule for this hohlraum design is driven by an adiabat-shaped [Betti et al., Phys. Plasmas 9, 2277 (2002)] 4-shock drive profile for robust high gain (>10) 1-D ignition performance and large margin to 2-D perturbation growth.

Evaluation and Characterization Study of Dual Pulse Laser-Induced Spark (DPLIS) for Rocket Engine Ignition System Application

NASA Technical Reports Server (NTRS)

Osborne, Robin; Wehrmeyer, Joseph; Trinh, Huu; Early, James

2003-01-01

This paper addresses the progress of technology development of a laser ignition system at NASA Marshall Space Flight Center (MSFC). Laser ignition has been used at MSFC in recent test series to successfully ignite RP1/GOX propellants in a subscale rocket chamber, and other past studies by NASA GRC have demonstrated the use of laser ignition for rocket engines. Despite the progress made in the study of this ignition method, the logistics of depositing laser sparks inside a rocket chamber have prohibited its use. However, recent advances in laser designs, the use of fiber optics, and studies of multi-pulse laser formats3 have renewed the interest of rocket designers in this state-of the-art technology which offers the potential elimination of torch igniter systems and their associated mechanical parts, as well as toxic hypergolic ignition systems. In support of this interest to develop an alternative ignition system that meets the risk-reduction demands of Next Generation Launch Technology (NGLT), characterization studies of a dual pulse laser format for laser-induced spark ignition are underway at MSFC. Results obtained at MSFC indicate that a dual pulse format can produce plasmas that absorb the laser energy as efficiently as a single pulse format, yet provide a longer plasma lifetime. In an experiments with lean H2/air propellants, the dual pulse laser format, containing the same total energy of a single laser pulse, produced a spark that was superior in its ability to provide sustained ignition of fuel-lean H2/air propellants. The results from these experiments are being used to optimize a dual pulse laser format for future subscale rocket chamber tests. Besides the ignition enhancement, the dual pulse technique provides a practical way to distribute and deliver laser light to the combustion chamber, an important consideration given the limitation of peak power that can be delivered through optical fibers. With this knowledge, scientists and engineers at Los Alamos National Laboratory and CFD Research Corporation have designed and fabricated a miniaturized, first-generation optical prototype of a laser ignition system that could be the basis for a laser ignition system for rocket applications. This prototype will be tested at MSFC in future subscale rocket ignition tests.

Experimental demonstration of low laser-plasma instabilities in gas-filled spherical hohlraums at laser injection angle designed for ignition target

NASA Astrophysics Data System (ADS)

Lan, Ke; Li, Zhichao; Xie, Xufei; Chen, Yao-Hua; Zheng, Chunyang; Zhai, Chuanlei; Hao, Liang; Yang, Dong; Huo, Wen Yi; Ren, Guoli; Peng, Xiaoshi; Xu, Tao; Li, Yulong; Li, Sanwei; Yang, Zhiwen; Guo, Liang; Hou, Lifei; Liu, Yonggang; Wei, Huiyue; Liu, Xiangming; Cha, Weiyi; Jiang, Xiaohua; Mei, Yu; Li, Yukun; Deng, Keli; Yuan, Zheng; Zhan, Xiayu; Zhang, Haijun; Jiang, Baibin; Zhang, Wei; Deng, Xuewei; Liu, Jie; Du, Kai; Ding, Yongkun; Wei, Xiaofeng; Zheng, Wanguo; Chen, Xiaodong; Campbell, E. M.; He, Xian-Tu

2017-03-01

Octahedral spherical hohlraums with a single laser ring at an injection angle of 55∘ are attractive concepts for laser indirect drive due to the potential for achieving the x-ray drive symmetry required for high convergence implosions. Laser-plasma instabilities, however, are a concern given the long laser propagation path in such hohlraums. Significant stimulated Raman scattering has been observed in cylindrical hohlraums with similar laser propagation paths during the ignition campaign on the National Ignition Facility (NIF). In this Rapid Communication, experiments demonstrating low levels of laser-driven plasma instability (LPI) in spherical hohlraums with a laser injection angle of 55∘ are reported and compared to that observed with cylindrical hohlraums with injection angles of 28 .5∘ and 55∘, similar to that of the NIF. Significant LPI is observed with the laser injection of 28 .5∘ in the cylindrical hohlraum where the propagation path is similar to the 55∘ injection angle for the spherical hohlraum. The experiments are performed on the SGIII laser facility with a total 0.35 -μ m incident energy of 93 kJ in a 3 nsec pulse. These experiments demonstrate the role of hohlraum geometry in LPI and demonstrate the need for systematic experiments for choosing the optimal configuration for ignition studies with indirect drive inertial confinement fusion.

Validating Hydrodynamic Growth in National Ignition Facility Implosions

NASA Astrophysics Data System (ADS)

Peterson, J. Luc

2014-10-01

The hydrodynamic growth of capsule imperfections can threaten the success of inertial confinement fusion implosions. Therefore, it is important to design implosions that are robust to hydrodynamic instabilities. However, the numerical simulation of interacting Rayleigh-Taylor and Richtmyer-Meshkov growth in these implosions is sensitive to modeling uncertainties such as radiation drive and material equations of state, the effects of which are especially apparent at high mode number (small perturbation wavelength) and high convergence ratio (small capsule radius). A series of validation experiments were conducted at the National Ignition Facility to test the ability to model hydrodynamic growth in spherically converging ignition-relevant implosions. These experiments on the Hydro-Growth Radiography platform constituted direct measurements of the growth of pre-imposed imperfections up to Legendre mode 160 and a convergence ratio of greater than four using two different laser drives: a ``low-foot'' drive used during the National Ignition Campaign and a larger adiabat ``high-foot'' drive that is modeled to be relatively more robust to ablation front hydrodynamic growth. We will discuss these experiments and how their results compare to numerical simulations and analytic theories of hydrodynamic growth, as well as their implications for the modeling of future designs. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Experimental demonstration of low laser-plasma instabilities in gas-filled spherical hohlraums at laser injection angle designed for ignition target.

PubMed

Lan, Ke; Li, Zhichao; Xie, Xufei; Chen, Yao-Hua; Zheng, Chunyang; Zhai, Chuanlei; Hao, Liang; Yang, Dong; Huo, Wen Yi; Ren, Guoli; Peng, Xiaoshi; Xu, Tao; Li, Yulong; Li, Sanwei; Yang, Zhiwen; Guo, Liang; Hou, Lifei; Liu, Yonggang; Wei, Huiyue; Liu, Xiangming; Cha, Weiyi; Jiang, Xiaohua; Mei, Yu; Li, Yukun; Deng, Keli; Yuan, Zheng; Zhan, Xiayu; Zhang, Haijun; Jiang, Baibin; Zhang, Wei; Deng, Xuewei; Liu, Jie; Du, Kai; Ding, Yongkun; Wei, Xiaofeng; Zheng, Wanguo; Chen, Xiaodong; Campbell, E M; He, Xian-Tu

2017-03-01

Octahedral spherical hohlraums with a single laser ring at an injection angle of 55^{∘} are attractive concepts for laser indirect drive due to the potential for achieving the x-ray drive symmetry required for high convergence implosions. Laser-plasma instabilities, however, are a concern given the long laser propagation path in such hohlraums. Significant stimulated Raman scattering has been observed in cylindrical hohlraums with similar laser propagation paths during the ignition campaign on the National Ignition Facility (NIF). In this Rapid Communication, experiments demonstrating low levels of laser-driven plasma instability (LPI) in spherical hohlraums with a laser injection angle of 55^{∘} are reported and compared to that observed with cylindrical hohlraums with injection angles of 28.5^{∘} and 55^{∘}, similar to that of the NIF. Significant LPI is observed with the laser injection of 28.5^{∘} in the cylindrical hohlraum where the propagation path is similar to the 55^{∘} injection angle for the spherical hohlraum. The experiments are performed on the SGIII laser facility with a total 0.35-μm incident energy of 93 kJ in a 3 nsec pulse. These experiments demonstrate the role of hohlraum geometry in LPI and demonstrate the need for systematic experiments for choosing the optimal configuration for ignition studies with indirect drive inertial confinement fusion.

The physics of sub-critical lattices in accelerator driven hybrid systems: The MUSE experiments in the MASURCA facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chauvin, J. P.; Lebrat, J. F.; Soule, R.

Since 1991, the CEA has studied the physics of hybrid systems, involving a sub-critical reactor coupled with an accelerator. These studies have provided information on the potential of hybrid systems to transmute actinides and, long lived fission products. The potential of such a system remains to be proven, specifically in terms of the physical understanding of the different phenomena involved and their modelling, as well as in terms of experimental validation of coupled systems, sub-critical environment/accelerator. This validation must be achieved through mock-up studies of the sub-critical environments coupled to a source of external neutrons. The MUSE-4 mock-up experiment ismore » planed at the MASURCA facility and will use an accelerator coupled to a tritium target. The great step between the generator used in the past and the accelerator will allow to increase the knowledge in hybrid physic and to decrease the experimental biases and the measurement uncertainties.« less

Precision Robotic Assembly Machine

ScienceCinema

None

2017-12-09

The world's largest laser system is the National Ignition Facility (NIF), located at Lawrence Livermore National Laboratory. NIF's 192 laser beams are amplified to extremely high energy, and then focused onto a tiny target about the size of a BB, containing frozen hydrogen gas. The target must be perfectly machined to incredibly demanding specifications. The Laboratory's scientists and engineers have developed a device called the "Precision Robotic Assembly Machine" for this purpose. Its unique design won a prestigious R&D-100 award from R&D Magazine.

Laser ignition application in a space experiment

NASA Technical Reports Server (NTRS)

Liou, Larry C.; Culley, Dennis E.

1993-01-01

A laser ignition system is proposed for the Combustion Experiment Module on an orbiting spacecraft. The results of a design study are given using the scheduled 'Flame Ball Experiment' as the design guidelines. Three laser ignition mechanisms and wavelengths are evaluated. A prototype laser is chosen and its specifications are given, followed by consideration of the beam optical arrangement, the ignition power requirement, the laser ignition system weight, size, reliability, and laser cooling and power consumption. Electromagnetic interference to the onboard electronics caused by the laser ignition process is discussed. Finally, ground tests are suggested.

X-ray transport and radiation response assessment (XTRRA) experiments at the National Ignition Facility

DOE PAGES

Fournier, K. B.; Brown, Jr., C. G.; Yeoman, M. F.; ...

2016-08-10

Our team has developed an experimental platform to evaluate the x-ray-generated stress and impulse in materials. Experimental activities include x-ray source development, design of the sample mounting hardware and sensors interfaced to the NIF’s diagnostics insertion system, and system integration into the facility. This paper focuses on the X-ray Transport and Radiation Response Assessment (XTRRA) test cassettes built for these experiments. The test cassette is designed to position six samples at three predetermined distances from the source, each known to within ±1% accuracy. Built in calorimeters give in situ measurements of the x-ray environment along the sample lines of sight.more » We discuss the measured accuracy of sample responses, as well as planned modifications to the XTRRA cassette.« less

Early-time radiation flux symmetry optimization and its effect on gas-filled hohlraum ignition targets on the National Ignition Facility

NASA Astrophysics Data System (ADS)

Milovich, J. L.; Dewald, E. L.; Pak, A.; Michel, P.; Town, R. P. J.; Bradley, D. K.; Landen, O.; Edwards, M. J.

2016-03-01

Achieving ignition on the National Ignition Facility (NIF) is tied to our ability to control and minimize deviations from sphericity of the capsule implosion. Low-mode asymmetries of the hot spot result from the combined effect of radiation drive asymmetries throughout the laser pulse and initial roughness on the capsule surface. In this paper, we report on simulations and experiments designed to assess, measure, and correct the drive asymmetries produced by the early-time (≈first 2 ns or "picket") period of the laser pulse. The drive asymmetry during the picket is commonly thought to introduce distortions in the hot-spot shape at ignition time. However, a more subtle effect not previously considered is that it also leads to an asymmetry in shock velocity and timing, thereby increasing the fuel adiabat and reducing the margin for ignition. It is shown via hydrodynamic simulations that minimizing this effect requires that the early-time asymmetry be kept below 7.5% in the second Legendre mode (P2), thus keeping the loss of performance margin below ≈10% for a layered implosion. Asymmetries during the picket of the laser pulse are measured using the instantaneous self-emission of a high-Z re-emission sphere in place of an ignition capsule in a hohlraum with large azimuthal diagnostic windows. Three dimensional simulations using the code HYDRA (to capture the effect of non-azimuthal hohlraum features) coupled to a cross-beam energy transfer model [Michel et al., Phys. Plasmas 17, 056305 (2010)] are used to establish the surrogacy of the re-emit target and to assess the early-time drive symmetry. Calculations using this model exhibit the same sensitivity to variations in the relative input powers between the different cones of NIF beams as measured for the "Rev5" CH target [Haan et al., Phys Plasmas 18, 051001 (2011)] and reported by Dewald et al. [Phys. Rev. Lett. 111, 235001 (2013)]. The same methodology applied to recently improved implosions using different hohlraum geometries and picket powers show good agreement with experimental data.

Facile Thermal and Optical Ignition of Silicon Nanoparticles and Micron Particles.

PubMed

Huang, Sidi; Parimi, Venkata Sharat; Deng, Sili; Lingamneni, Srilakshmi; Zheng, Xiaolin

2017-10-11

Silicon (Si) particles are widely utilized as high-capacity electrodes for Li-ion batteries, elements for thermoelectric devices, agents for bioimaging and therapy, and many other applications. However, Si particles can ignite and burn in air at elevated temperatures or under intense illumination. This poses potential safety hazards when handling, storing, and utilizing these particles for those applications. In order to avoid the problem of accidental ignition, it is critical to quantify the ignition properties of Si particles such as their sizes and porosities. To do so, we first used differential scanning calorimetry to experimentally determine the reaction onset temperature of Si particles under slow heating rates (∼0.33 K/s). We found that the reaction onset temperature of Si particles increased with the particle diameter from 805 °C at 20-30 nm to 935 °C at 1-5 μm. Then, we used a xenon (Xe) flash lamp to ignite Si particles under fast heating rates (∼10 3 to 10 6 K/s) and measured the minimum ignition radiant fluence (i.e., the radiant energy per unit surface area of Si particle beds required for ignition). We found that the measured minimum ignition radiant fluence decreased with decreasing Si particle size and was most sensitive to the porosity of the Si particle bed. These trends for the Xe flash ignition experiments were also confirmed by our one-dimensional unsteady simulation to model the heat transfer process. The quantitative information on Si particle ignition included in this Letter will guide the safe handling, storage, and utilization of Si particles for diverse applications and prevent unwanted fire hazards.

Characteristics and performance of a two-lens slit spatial filter for high power lasers

NASA Astrophysics Data System (ADS)

Xiong, Han; Gao, Fan; Zhang, Xiang; Zhuang, Zhenwu; Zhao, Jianjun; Yuan, Xiao

2017-05-01

The characteristics of a two-lens slit spatial filtering system on image relay and spatial filtering are discussed with detailed theoretical calculation and numerical simulation. The slit spatial filter can be used as the cavity spatial filter in large laser systems, such as National Ignition Facility, which can significantly decrease the focal intensity in cavity spatial filter and suppress or even avoid the pinhole (slit) closure while keeping the output power and beam quality. Additionally, the overall length of the cavity spatial filter can be greatly reduced with the use of the two-lens slit spatial filter.

Research on measurement of aviation magneto ignition strength and balance

NASA Astrophysics Data System (ADS)

Gao, Feng; He, Zhixiang; Zhang, Dingpeng

2017-12-01

Aviation magneto ignition system failure accounted for two-thirds of the total fault aviation piston engine and above. At present the method used for this failure diagnosis is often depended on the visual inspections in the civil aviation maintenance field. Due to human factors, the visual inspections cannot provide ignition intensity value and ignition equilibrium deviation value among the different spark plugs in the different cylinder of aviation piston engine. So air magneto ignition strength and balance testing has become an aviation piston engine maintenance technical problem needed to resolve. In this paper, the ultraviolet sensor with detection wavelength of 185~260nm and driving voltage of 320V DC is used as the core of ultraviolet detection to detect the ignition intensity of Aviation magneto ignition system and the balance deviation of the ignition intensity of each cylinder. The experimental results show that the rotational speed within the range 0 to 3500 RPM test error less than 0.34%, ignition strength analysis and calculation error is less than 0.13%, and measured the visual inspection is hard to distinguish between high voltage wire leakage failure of deviation value of 200 pulse ignition strength balance/Sec. The method to detect aviation piston engine maintenance of magneto ignition system fault has a certain reference value.

Ignition and Performance Tests of Rocket-Based Combined Cycle Propulsion System

NASA Technical Reports Server (NTRS)

Anderson, William E.

2005-01-01

The ground testing of a Rocket Based Combined Cycle engine implementing the Simultaneous Mixing and Combustion scheme was performed at the direct-connect facility of Purdue University's High Pressure Laboratory. The fuel-rich exhaust of a JP-8/H2O2 thruster was mixed with compressed, metered air in a constant area, axisymmetric duct. The thruster was similar in design and function to that which will be used in the flight test series of Dryden's Ducted-Rocket Experiment. The determination of duct ignition limits was made based on the variation of secondary air flow rates and primary thruster equivalence ratios. Thrust augmentation and improvements in specific impulse were studied along with the pressure and temperature profiles of the duct to study mixing lengths and thermal choking. The occurrence of ignition was favored by lower rocket equivalence ratios. However, among ignition cases, better thrust and specific impulse performance were seen with higher equivalence ratios owing to the increased fuel available for combustion. Thrust and specific impulse improvements by factors of 1.2 to 1.7 were seen. The static pressure and temperature profiles allowed regions of mixing and heat addition to be identified. The mixing lengths were found to be shorter at lower rocket equivalence ratios. Total pressure measurements allowed plume-based calculation of thrust, which agreed with load-cell measured values to within 6.5-8.0%. The corresponding Mach Number profile indicated the flow was not thermally choked for the highest duct static pressure case.

Three-dimensional simulations of low foot and high foot implosion experiments on the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, D. S.; Weber, C. R.; Milovich, J. L.

In order to achieve the several hundred Gbar stagnation pressures necessary for inertial confinement fusion ignition, implosion experiments on the National Ignition Facility (NIF) [E. I. Moses et al., Phys. Plasmas 16, 041006 (2009)] require the compression of deuterium-tritium fuel layers by a convergence ratio as high as forty. Such high convergence implosions are subject to degradation by a range of perturbations, including the growth of small-scale defects due to hydrodynamic instabilities, as well as longer scale modulations due to radiation flux asymmetries in the enclosing hohlraum. Due to the broad range of scales involved, and also the genuinely three-dimensionalmore » (3D) character of the flow, accurately modeling NIF implosions remains at the edge of current simulation capabilities. This study describes the current state of progress of 3D capsule-only simulations of NIF implosions aimed at accurately describing the performance of specific NIF experiments. Current simulations include the effects of hohlraum radiation asymmetries, capsule surface defects, the capsule support tent and fill tube, and use a grid resolution shown to be converged in companion two-dimensional simulations. The results of detailed simulations of low foot implosions from the National Ignition Campaign are contrasted against results for more recent high foot implosions. While the simulations suggest that low foot performance was dominated by ablation front instability growth, especially the defect seeded by the capsule support tent, high foot implosions appear to be dominated by hohlraum flux asymmetries, although the support tent still plays a significant role. Finally, for both implosion types, the simulations show reasonable, though not perfect, agreement with the data and suggest that a reliable predictive capability is developing to guide future implosions toward ignition.« less

Three-dimensional simulations of low foot and high foot implosion experiments on the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, D. S.; Weber, C. R.; Milovich, J. L.

In order to achieve the several hundred Gbar stagnation pressures necessary for inertial confinement fusion ignition, implosion experiments on the National Ignition Facility (NIF) [E. I. Moses et al., Phys. Plasmas 16, 041006 (2009)] require the compression of deuterium-tritium fuel layers by a convergence ratio as high as forty. Such high convergence implosions are subject to degradation by a range of perturbations, including the growth of small-scale defects due to hydrodynamic instabilities, as well as longer scale modulations due to radiation flux asymmetries in the enclosing hohlraum. Due to the broad range of scales involved, and also the genuinely three-dimensionalmore » (3D) character of the flow, accurately modeling NIF implosions remains at the edge of current simulation capabilities. This paper describes the current state of progress of 3D capsule-only simulations of NIF implosions aimed at accurately describing the performance of specific NIF experiments. Current simulations include the effects of hohlraum radiation asymmetries, capsule surface defects, the capsule support tent and fill tube, and use a grid resolution shown to be converged in companion two-dimensional simulations. The results of detailed simulations of low foot implosions from the National Ignition Campaign are contrasted against results for more recent high foot implosions. While the simulations suggest that low foot performance was dominated by ablation front instability growth, especially the defect seeded by the capsule support tent, high foot implosions appear to be dominated by hohlraum flux asymmetries, although the support tent still plays a significant role. For both implosion types, the simulations show reasonable, though not perfect, agreement with the data and suggest that a reliable predictive capability is developing to guide future implosions toward ignition.« less

Three-dimensional simulations of low foot and high foot implosion experiments on the National Ignition Facility

DOE PAGES

Clark, D. S.; Weber, C. R.; Milovich, J. L.; ...

2016-03-14

In order to achieve the several hundred Gbar stagnation pressures necessary for inertial confinement fusion ignition, implosion experiments on the National Ignition Facility (NIF) [E. I. Moses et al., Phys. Plasmas 16, 041006 (2009)] require the compression of deuterium-tritium fuel layers by a convergence ratio as high as forty. Such high convergence implosions are subject to degradation by a range of perturbations, including the growth of small-scale defects due to hydrodynamic instabilities, as well as longer scale modulations due to radiation flux asymmetries in the enclosing hohlraum. Due to the broad range of scales involved, and also the genuinely three-dimensionalmore » (3D) character of the flow, accurately modeling NIF implosions remains at the edge of current simulation capabilities. This study describes the current state of progress of 3D capsule-only simulations of NIF implosions aimed at accurately describing the performance of specific NIF experiments. Current simulations include the effects of hohlraum radiation asymmetries, capsule surface defects, the capsule support tent and fill tube, and use a grid resolution shown to be converged in companion two-dimensional simulations. The results of detailed simulations of low foot implosions from the National Ignition Campaign are contrasted against results for more recent high foot implosions. While the simulations suggest that low foot performance was dominated by ablation front instability growth, especially the defect seeded by the capsule support tent, high foot implosions appear to be dominated by hohlraum flux asymmetries, although the support tent still plays a significant role. Finally, for both implosion types, the simulations show reasonable, though not perfect, agreement with the data and suggest that a reliable predictive capability is developing to guide future implosions toward ignition.« less

Polar-Drive Experiments at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Hohenberger, M.

2014-10-01

To support direct-drive inertial confinement fusion (ICF) experiments at the National Ignition Facility (NIF) in its indirect-drive beam configuration, the polar-drive (PD) concept has been proposed. It requires direct-drive-specific beam smoothing, phase plates, and repointing the NIF beams toward the equator to ensure symmetric target irradiation. First experiments testing the performance of ignition-relevant PD implosions at the NIF have been performed. The goal of these early experiments was to develop a stable, warm implosion platform to investigate laser deposition and laser-plasma instabilities at ignition-relevant plasma conditions, and to develop and validate ignition-relevant models of laser deposition and heat conduction. These experiments utilize the NIF in its current configuration, including beam geometry, phase plates, and beam smoothing. Warm, 2.2-mm-diam plastic shells were imploded with total drive energies ranging from ~ 350 to 750 kJ with peak powers of 60 to 180 TW and peak on-target intensities from 4 ×1014 to 1 . 2 ×1015 W/cm2. Results from these initial experiments are presented, including the level of hot-electron preheat, and implosion symmetry and shell trajectory inferred via self-emission imaging and backlighting. Experiments are simulated with the 2-D hydrodynamics code DRACO including a full 3-D ray trace to model oblique beams, and a model for cross-beam energy transfer (CBET). These simulations indicate that CBET affects the shell symmetry and leads to a loss of energy imparted onto the shell, consistent with the experimental data. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

A recoverable gas-cell diagnostic for the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ratkiewicz, A., E-mail: ratkiewicz1@llnl.gov; Berzak Hopkins, L.; Bleuel, D. L.

2016-11-15

The high-fluence neutron spectrum produced by the National Ignition Facility (NIF) provides an opportunity to measure the activation of materials by fast-spectrum neutrons. A new large-volume gas-cell diagnostic has been designed and qualified to measure the activation of gaseous substances at the NIF. This in-chamber diagnostic is recoverable, reusable and has been successfully fielded. Data from the qualification of the diagnostic have been used to benchmark an Monte Carlo N-Particle Transport Code simulation describing the downscattered neutron spectrum seen by the gas cell. We present early results from the use of this diagnostic to measure the activation of {sup nat}Xemore » and discuss future work to study the strength of interactions between plasma and nuclei.« less

Advances in shock timing experiments on the National Ignition Facility

NASA Astrophysics Data System (ADS)

Robey, H. F.; Celliers, P. M.; Moody, J. D.; Sater, J.; Parham, T.; Kozioziemski, B.; Dylla-Spears, R.; Ross, J. S.; LePape, S.; Ralph, J. E.; Hohenberger, M.; Dewald, E. L.; Berzak Hopkins, L.; Kroll, J. J.; Yoxall, B. E.; Hamza, A. V.; Boehly, T. R.; Nikroo, A.; Landen, O. L.; Edwards, M. J.

2016-03-01

Recent advances in shock timing experiments and analysis techniques now enable shock measurements to be performed in cryogenic deuterium-tritium (DT) ice layered capsule implosions on the National Ignition Facility (NIF). Previous measurements of shock timing in inertial confinement fusion (ICF) implosions were performed in surrogate targets, where the solid DT ice shell and central DT gas were replaced with a continuous liquid deuterium (D2) fill. These previous experiments pose two surrogacy issues: a material surrogacy due to the difference of species (D2 vs. DT) and densities of the materials used and a geometric surrogacy due to presence of an additional interface (ice/gas) previously absent in the liquid-filled targets. This report presents experimental data and a new analysis method for validating the assumptions underlying this surrogate technique.

A recoverable gas-cell diagnostic for the National Ignition Facility

DOE PAGES

Ratkiewicz, A.; Hopkins, L. Berzak; Bleuel, D. L.; ...

2016-08-22

Here, the high-fluence neutron spectrum produced by the National Ignition Facility (NIF) provides an opportunity to measure the activation of materials by fast-spectrum neutrons. A new large-volume gas-cell diagnostic has been designed and qualified to measure the activation of gaseous substances at the NIF. This in-chamber diagnostic is recoverable, reusable and has been successfully fielded. Data from the qualification of the diagnostic have been used to benchmark an Monte Carlo N-Particle Transport Code simulation describing the downscattered neutron spectrum seen by the gas cell. We present early results from the use of this diagnostic to measure the activation of natXemore » and discuss future work to study the strength of interactions between plasma and nuclei.« less

Time-of-Flight Measurements of Neutron Yields from Implosions at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Caggaino, Joseph

2014-10-01

Three 20-m time-of-flight detectors measure neutron spectra from implosions of deuterium-tritium targets at the National Ignition Facility. Two prominent peaks appear in the spectra from the T(d, n) and D(d, n) reactions. The ratio of yields extracted from the peaks depend on the DT and DD reaction rates and attenuation from the compressed DT fuel, which makes the ratio a diagnostic of the hotspot thermodynamics and fuel areal density. The measured peak widths provide additional constraints on reactant temperature. Recent measurements from a high-yield campaign will be presented and compared to radiation-hydrodynamic simulations of similar implosions. This research is supported by the Department of Energy National Nuclear Security Administration under Contract DE-NA0001944.

First Observation of Cross-Beam Energy Transfer Mitigation for Direct-Drive Inertial Confinement Fusion Implosions Using Wavelength Detuning at the National Ignition Facility

DOE PAGES

Marozas, J. A.; Hohenberger, M.; Rosenberg, M. J.; ...

2018-02-22

Cross-beam energy transfer (CBET) results from two-beam energy exchange via seeded stimulated Brillouin scattering, which detrimentally reduces ablation pressure and implosion velocity in direct-drive inertial confinement fusion. Direct-drive implosions at the National Ignition Facility were conducted to reduce CBET by detuning the laser-source wavelengths (±2.3 Å UV) of the interacting beams over the equatorial region of the target. For the first time, wavelength detuning was shown to increase the equatorial region velocity experimentally by 16% and to alter the in-flight shell morphology. These experimental observations are consistent with design predictions of radiation–hydrodynamic simulations that indicate a 10% increase in themore » average ablation pressure.« less

First Observation of Cross-Beam Energy Transfer Mitigation for Direct-Drive Inertial Confinement Fusion Implosions Using Wavelength Detuning at the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marozas, J. A.; Hohenberger, M.; Rosenberg, M. J.

Cross-beam energy transfer (CBET) results from two-beam energy exchange via seeded stimulated Brillouin scattering, which detrimentally reduces ablation pressure and implosion velocity in direct-drive inertial confinement fusion. Direct-drive implosions at the National Ignition Facility were conducted to reduce CBET by detuning the laser-source wavelengths (±2.3 Å UV) of the interacting beams over the equatorial region of the target. For the first time, wavelength detuning was shown to increase the equatorial region velocity experimentally by 16% and to alter the in-flight shell morphology. These experimental observations are consistent with design predictions of radiation–hydrodynamic simulations that indicate a 10% increase in themore » average ablation pressure.« less

Computational Analyses in Support of Sub-scale Diffuser Testing for the A-3 Facility. Part 1; Steady Predictions

NASA Technical Reports Server (NTRS)

Allgood, Daniel C.; Graham, Jason S.; Ahuja, Vineet; Hosangadi, Ashvin

2010-01-01

Simulation technology can play an important role in rocket engine test facility design and development by assessing risks, providing analysis of dynamic pressure and thermal loads, identifying failure modes and predicting anomalous behavior of critical systems. Advanced numerical tools assume greater significance in supporting testing and design of high altitude testing facilities and plume induced testing environments of high thrust engines because of the greater inter-dependence and synergy in the functioning of the different sub-systems. This is especially true for facilities such as the proposed A-3 facility at NASA SSC because of a challenging operating envelope linked to variable throttle conditions at relatively low chamber pressures. Facility designs in this case will require a complex network of diffuser ducts, steam ejector trains, fast operating valves, cooling water systems and flow diverters that need to be characterized for steady state performance. In this paper, we will demonstrate with the use of CFD analyses s advanced capability to evaluate supersonic diffuser and steam ejector performance in a sub-scale A-3 facility at NASA Stennis Space Center (SSC) where extensive testing was performed. Furthermore, the focus in this paper relates to modeling of critical sub-systems and components used in facilities such as the A-3 facility. The work here will address deficiencies in empirical models and current CFD analyses that are used for design of supersonic diffusers/turning vanes/ejectors as well as analyses for confined plumes and venting processes. The primary areas that will be addressed are: (1) supersonic diffuser performance including analyses of thermal loads (2) accurate shock capturing in the diffuser duct; (3) effect of turning duct on the performance of the facility (4) prediction of mass flow rates and performance classification for steam ejectors (5) comparisons with test data from sub-scale diffuser testing and assessment of confidence levels in CFD based flowpath modeling of the facility. The analyses tools used here expand on the multi-element unstructured CFD which has been tailored and validated for impingement dynamics of dry plumes, complex valve/feed systems, and high pressure propellant delivery systems used in engine and component test stands at NASA SSC. The analyses performed in the evaluation of the sub-scale diffuser facility explored several important factors that influence modeling and understanding of facility operation such as (a) importance of modeling the facility with Real Gas approximation, (b) approximating the cluster of steam ejector nozzles as a single annular nozzle, (c) existence of mixed subsonic/supersonic flow downstream of the turning duct, and (d) inadequacy of two-equation turbulence models in predicting the correct pressurization in the turning duct and expansion of the second stage steam ejectors. The procedure used for modeling the facility was as follows: (i) The engine, test cell and first stage ejectors were simulated with an axisymmetric approximation (ii) the turning duct, second stage ejectors and the piping downstream of the second stage ejectors were analyzed with a three-dimensional simulation utilizing a half-plane symmetry approximation. The solution i.e. primitive variables such as pressure, velocity components, temperature and turbulence quantities were passed from the first computational domain and specified as a supersonic boundary condition for the second simulation. (iii) The third domain comprised of the exit diffuser and the region in the vicinity of the facility (primary included to get the correct shock structure at the exit of the facility and entrainment characteristics). The first set of simulations comprising the engine, test cell and first stage ejectors was carried out both as a turbulent real gas calculation as well as a turbulent perfect gas calculation. A comparison for the two cases (Real Turbulent and Perfect gas turbulent) of the Ma Number distribution and temperature distributions are shown in Figures 1 and 2 respectively.

14 CFR 25.1165 - Engine ignition systems.

Code of Federal Regulations, 2010 CFR

2010-01-01

... automatically available as an alternate source of electrical energy to allow continued engine operation if any... simultaneous demands of the engine ignition system and the greatest demands of any electrical system components that draw electrical energy from the same source. (c) The design of the engine ignition system must...

14 CFR 25.1165 - Engine ignition systems.

Code of Federal Regulations, 2011 CFR

2011-01-01

... automatically available as an alternate source of electrical energy to allow continued engine operation if any... simultaneous demands of the engine ignition system and the greatest demands of any electrical system components that draw electrical energy from the same source. (c) The design of the engine ignition system must...

Experimental investigation of the auto-ignition characteristics of oxygenated reference fuel compounds

NASA Astrophysics Data System (ADS)

Walton, Stephen Michael

The increased use of biofuels presents an opportunity to improve combustion performance while simultaneously reducing greenhouse gases and pollutant emissions. This work focused on improving the fundamental understanding of the auto-ignition chemistry of oxygenated reference fuel compounds. A systematic study of the effects of ester structure on ignition chemistry was performed using the University of Michigan Rapid Compression Facility. The ignition properties of the ester compounds were investigated over a broad range of pressures (P=5-20 atm) and temperatures (T=850-1150 K) which are directly relevant to advanced combustion engine strategies. Ignition delay times for five esters were determined using the RCF. The esters were selected to systematically consider the chemical structure of the compounds. Three esters were saturated: methyl butanoate, butyl methanoate, and ethyl propanoate; and two were unsaturated: methyl crotonate and methyl trans-3-hexenoate. The unsaturated esters were more reactive than their saturated counterparts, with the largest unsaturated ester, methyl trans-3-hexenoate having the highest reactivity. Two isomers of the saturated esters, butyl methanoate and ethyl propanoate, were more reactive than the isomer methyl butanoate. The results are explained if we assume that butyl methanoate and ethyl propanoate form intermediate ring structures which decompose more rapidly than esters such as methyl butanoate, which do not form ring structures. Modeling studies of the reaction chemistry were conducted for methyl butanoate and ethyl propanoate, for which detailed mechanisms were available in the literature. The new experimental data indicated that literature rate coefficients for some of the methyl butanoate/HO2 reactions were too fast. Modifying these within the theoretical uncertainties for the reaction rates, led to excellent agreement between the model predictions and the experimental data. Comparison of the modeling results with the intermediates measured during methyl butanoate ignition indicated that pathways leading to the formation of small hydrocarbons are relatively well represented in the reaction mechanism. The results of this work provide archival benchmark data for improved understanding of the dominant reaction pathways and species controlling the auto-ignition of oxygenated reference fuel compounds. These data also provide a path for continued development of chemical kinetic models to optimize practical combustion systems.

14 CFR 33.37 - Ignition system.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Ignition system. 33.37 Section 33.37 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Reciprocating Aircraft Engines § 33.37 Ignition system...

14 CFR 33.69 - Ignitions system.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.69 Ignitions system. Each engine must be equipped with an ignition system for starting the engine on the ground and in flight. An...

14 CFR 33.69 - Ignitions system.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.69 Ignitions system. Each engine must be equipped with an ignition system for starting the engine on the ground and in flight. An...

Next generation gamma-ray Cherenkov detectors for the National Ignition Facility.

PubMed

Herrmann, H W; Kim, Y H; McEvoy, A M; Zylstra, A B; Young, C S; Lopez, F E; Griego, J R; Fatherley, V E; Oertel, J A; Stoeffl, W; Khater, H; Hernandez, J E; Carpenter, A; Rubery, M S; Horsfield, C J; Gales, S; Leatherland, A; Hilsabeck, T; Kilkenny, J D; Malone, R M; Hares, J D; Milnes, J; Shmayda, W T; Stoeckl, C; Batha, S H

2016-11-01

The newest generation of Gas Cherenkov Detector (GCD-3) employed in Inertial Confinement Fusion experiments at the Omega Laser Facility has provided improved performance over previous generations. Comparison of reaction histories measured using two different deuterium-tritium fusion products, namely gamma rays using GCD and neutrons using Neutron Temporal Diagnostic (NTD), have provided added credibility to both techniques. GCD-3 is now being brought to the National Ignition Facility (NIF) to supplement the existing Gamma Reaction History (GRH-6m) located 6 m from target chamber center (TCC). Initially it will be located in a reentrant well located 3.9 m from TCC. Data from GCD-3 will inform the design of a heavily-shielded "Super" GCD to be located as close as 20 cm from TCC. It will also provide a test-bed for faster optical detectors, potentially lowering the temporal resolution from the current ∼100 ps state-of-the-art photomultiplier tubes (PMT) to ∼10 ps Pulse Dilation PMT technology currently under development.

The first target experiments on the National Ignition Facility

NASA Astrophysics Data System (ADS)

Landen, O. L.; Glenzer, S. H.; Froula, D. H.; Dewald, E. L.; Suter, L. J.; Schneider, M. B.; Hinkel, D. E.; Fernandez, J. C.; Kline, J. L.; Goldman, S. R.; Braun, D. G.; Celliers, P. M.; Moon, S. J.; Robey, H. S.; Lanier, N. E.; Glendinning, S. G.; Blue, B. E.; Wilde, B. H.; Jones, O. S.; Schein, J.; Divol, L.; Kalantar, D. H.; Campbell, K. M.; Holder, J. P.; McDonald, J. W.; Niemann, C.; MacKinnon, A. J.; Collins, G. W.; Bradley, D. K.; Eggert, J. H.; Hicks, D. G.; Gregori, G.; Kirkwood, R. K.; Young, B. K.; Foster, J. M.; Hansen, J. F.; Perry, T. S.; Munro, D. H.; Baldis, H. A.; Grim, G. P.; Heeter, R. F.; Hegelich, M. B.; Montgomery, D. S.; Rochau, G. A.; Olson, R. E.; Turner, R. E.; Workman, J. B.; Berger, R. L.; Cohen, B. I.; Kruer, W. L.; Langdon, A. B.; Langer, S. H.; Meezan, N. B.; Rose, H. A.; Still, C. H.; Williams, E. A.; Dodd, E. S.; Edwards, M. J.; Monteil, M.-C.; Stevenson, R. M.; Thomas, B. R.; Coker, R. F.; Magelssen, G. R.; Rosen, P. A.; Stry, P. E.; Woods, D.; Weber, S. V.; Young, P. E.; Alvarez, S.; Armstrong, G.; Bahr, R.; Bourgade, J.-L.; Bower, D.; Celeste, J.; Chrisp, M.; Compton, S.; Cox, J.; Constantin, C.; Costa, R.; Duncan, J.; Ellis, A.; Emig, J.; Gautier, C.; Greenwood, A.; Griffith, R.; Holdner, F.; Holtmeier, G.; Hargrove, D.; James, T.; Kamperschroer, J.; Kimbrough, J.; Landon, M.; Lee, F. D.; Malone, R.; May, M.; Montelongo, S.; Moody, J.; Ng, E.; Nikitin, A.; Pellinen, D.; Piston, K.; Poole, M.; Rekow, V.; Rhodes, M.; Shepherd, R.; Shiromizu, S.; Voloshin, D.; Warrick, A.; Watts, P.; Weber, F.; Young, P.; Arnold, P.; Atherton, L.; Bardsley, G.; Bonanno, R.; Borger, T.; Bowers, M.; Bryant, R.; Buckman, S.; Burkhart, S.; Cooper, F.; Dixit, S. N.; Erbert, G.; Eder, D. C.; Ehrlich, R. E.; Felker, B.; Fornes, J.; Frieders, G.; Gardner, S.; Gates, C.; Gonzalez, M.; Grace, S.; Hall, T.; Haynam, C. A.; Heestand, G.; Henesian, M. A.; Hermann, M.; Hermes, G.; Huber, S.; Jancaitis, K.; Johnson, S.; Kauffman, B.; Kelleher, T.; Kohut, T.; Koniges, A. E.; Labiak, T.; Latray, D.; Lee, A.; Lund, D.; Mahavandi, S.; Manes, K. R.; Marshall, C.; McBride, J.; McCarville, T.; McGrew, L.; Menapace, J.; Mertens, E.; Murray, J.; Neumann, J.; Newton, M.; Opsahl, P.; Padilla, E.; Parham, T.; Parrish, G.; Petty, C.; Polk, M.; Powell, C.; Reinbachs, I.; Rinnert, R.; Riordan, B.; Ross, G.; Robert, V.; Tobin, M.; Sailors, S.; Saunders, R.; Schmitt, M.; Shaw, M.; Singh, M.; Spaeth, M.; Stephens, A.; Tietbohl, G.; Tuck, J.; van Wonterghem, B. M.; Vidal, R.; Wegner, P. J.; Whitman, P.; Williams, K.; Winward, K.; Work, K.; Wallace, R.; Nobile, A.; Bono, M.; Day, B.; Elliott, J.; Hatch, D.; Louis, H.; Manzenares, R.; O'Brien, D.; Papin, P.; Pierce, T.; Rivera, G.; Ruppe, J.; Sandoval, D.; Schmidt, D.; Valdez, L.; Zapata, K.; MacGowan, B. J.; Eckart, M. J.; Hsing, W. W.; Springer, P. T.; Hammel, B. A.; Moses, E. I.; Miller, G. H.

2007-08-01

A first set of shock timing, laser-plasma interaction, hohlraum energetics and hydrodynamic experiments have been performed using the first 4 beams of the National Ignition Facility (NIF), in support of indirect drive Inertial Confinement Fusion (ICF) and High Energy Density Physics (HEDP). In parallel, a robust set of optical and X-ray spectrometers, interferometer, calorimeters and imagers have been activated. The experiments have been undertaken with laser powers and energies of up to 8 TW and 17 kJ in flattop and shaped 1 9 ns pulses focused with various beam smoothing options. The experiments have demonstrated excellent agreement between measured and predicted laser-target coupling in foils and hohlraums, even when extended to a longer pulse regime unattainable at previous laser facilities, validated the predicted effects of beam smoothing on intense laser beam propagation in long scale-length plasmas and begun to test 3D codes by extending the study of laser driven hydrodynamic jets to 3D geometries.

Standard design for National Ignition Facility x-ray streak and framing cameras.

PubMed

Kimbrough, J R; Bell, P M; Bradley, D K; Holder, J P; Kalantar, D K; MacPhee, A G; Telford, S

2010-10-01

The x-ray streak camera and x-ray framing camera for the National Ignition Facility were redesigned to improve electromagnetic pulse hardening, protect high voltage circuits from pressure transients, and maximize the use of common parts and operational software. Both instruments use the same PC104 based controller, interface, power supply, charge coupled device camera, protective hermetically sealed housing, and mechanical interfaces. Communication is over fiber optics with identical facility hardware for both instruments. Each has three triggers that can be either fiber optic or coax. High voltage protection consists of a vacuum sensor to enable the high voltage and pulsed microchannel plate phosphor voltage. In the streak camera, the high voltage is removed after the sweep. Both rely on the hardened aluminum box and a custom power supply to reduce electromagnetic pulse/electromagnetic interference (EMP/EMI) getting into the electronics. In addition, the streak camera has an EMP/EMI shield enclosing the front of the streak tube.