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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,099 records · Page 61
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Oxygen/hydrogen component technology status.

The advanced technology applicable to oxygen/hydrogen systems for auxiliary propulsion systems and other high energy upper stage applications is being developed. Turbopump, propellant conditioner (gas generator and heat exchanger), thruster, igniter, valve, and flow controller components are being evaluated. A brief description of turbopump, conditioner, valve, and thruster experimental programs is presented. Design and hot-firing test data are discussed.

Fulton, D. L.↗
NASA NTRS1984

Selection of burn-resistant materials for oxygen-driven turbopumps

NASA goals for reusable space-based, high-performance orbit transfer vehicle propulsion systems have resulted in a need for oxygen/hydrogen engines which include lightweight, highly reliable, liquid oxygen pumps. The selection of ignition- and burn-resistant materials is a major factor in the design of a compact 75,000-rpm turbopump which can deliver 6 lbM/sec of liquid oxygen at 5,000 psia. The potential operational hazards of rubbing friction and impact of foreign particles at high velocity were investigated experimentally for a wide range of candidate materials, i.e., nickel, copper, monel, 316 Stainless Steel, Hastelloy-X, Invar-36, and silicon carbide. Test parameters included oxygen pressure and temperature up to 5,000 psia and 800 F, respectively. The effect of increasing the O2 pressure from 1000 to 5000 psi is discussed. The applicability of the candidate materials to oxygen pump design was ranked by comparing the experimental results among themselves and with an analytically determined parameter, i.e., the burn factor. Nickel and copper demonstrated superior resistance to ignition and burn in the friction rubbing and particle impact tests relative to monel, stainless steel, and nickel-iron base superalloys.

Schoenman, L.↗
NASA NTRS1985

Dynamic features of combustion

The dynamic features of combustion are discussed for four important cases: ignition, inflammation, explosion, and detonation. Ignition, the initiation of a self-sustained exothermic process, is considered in the simplest case of a closed thermodynamic system and its stochastic distribution. Inflammation, the initiation and propagation of self-sustained flames, is presented for turbulent flow. Explosion, the dynamic effects caused by the deposition of exothermic energy in a compressible medium, is illustrated by self-similar blast waves with energy deposition at the front and the adiabatic non-self-similar wave. Detonation, the most comprehensive illustration of all the dynamic effects of combustion, is discussed with a phenomenological account of the development and structure of the wave.

Oppenheim, A. K.↗
NASA NTRS2015

LOx / LCH4: A Unifying Technology for Future Exploration

Reduced mass due to increasing commonality between spacecraft subsystems such as power and propulsion have been identified as critical to enabling human missions to Mars. This project represents the first ever integrated propulsion and power system testing and lays the foundations for future sounding rocket flight testing, which will yield the first in-space ignition of a LOx / LCH4 rocket engine.

Falker, John↗
NASA NTRS2016

Astronaut Clothing for Exploration Missions

Astronaut clothes for exploration missions beyond low Earth orbit need to satisfy several challenges not met by the currently-used mostly-cotton clothing. A laundering system is not expected to be available, and thus soiled garments must be trashed. Jettisoning waste does not seem feasible at this time. The cabin oxygen concentration is expected to be higher than standard, and thus fabrics must better resist ignition and burning. Fabrics need to be identified that reduce logistical mass, that can be worn longer before disposal, that are at least as comfortable as cotton, and that resist ignition or that char immediately after ignition. Human factors and psychology indicate that crew well-being and morale require a variety of colors and styles to accommodate personal identity and preferences. Over the past four years, the Logistics Reduction Project under NASA's Advanced Exploration Systems Program has sponsored the Advanced Clothing System Task to conduct several ground studies and one ISS study. These studies have evaluated length of wear and personal preferences of commercially-available exercise- and routine-wear garments made from several fabrics (cotton, polyester, Merino wool, and modacrylic), woven and knitted. Note that Merino wool and modacrylic char like cotton in ambient air, while polyester unacceptably melts. This paper focuses on the two components of an International Space Station study, onboard and on the ground, with astronauts and cosmonauts. Fabrics were randomized to participants. Length of wear was assessed by statistical survival analysis, and preference by exact binomial confidence limits. Merino wool and modacrylic t-shirts were worn longer on average than polyester t-shirts. Interestingly, self-assessed preferences were inconsistent with length-of-wear behavior, as polyester was preferred to Merino wool and modacrylic.

Poritz, Darwin H.↗
DOE OSTI2016

FUEL EFFECTS ON COMBUSTION WITH EGR DILUTION IN SPARK IGNITED ENGINES

The use of EGR as a diluent allows operation with an overall stoichiometric charge composition, and the addition of cooled EGR results in well-understood thermodynamic benefits for improved fuel consumption. This study investigates the effect of fuel on the combustion and emission response of EGR dilution in spark ignited engines. A 2.0 L GM Ecotec LNF engine equipped with the production side-mounted direct injection (DI) fueling system is used in this study. Ethanol, isooctane and certified gasoline are investigated with EGR from 0% to the EGR dilution tolerance. Constant BMEP at 2000 rpm was operated with varying CA50 from 8 CAD to 16 CAD aTDCf. The results show that ethanol gives the largest EGR tolerance at a given combustion phasing, engine load and speed. The improved EGR dilution tolerance with ethanol is attributed to a faster flame speed, which manifests itself as shorter combustion duration. Data shows that the combustion stability limit occurs at a critical combustion duration that is fuel independent. Due to different flame speeds, this critical combustion duration occurs at different EGR levels for the different fuels.

COV↗
DOE OSTI2024

Recent Progress on Numerical Modeling for Microgravity Electric Field Flames: Preprint

This paper presents the recent progress on the NASA Physical Science Informatics (PSI) project PeleLM CFD of Ion Driven Winds from Diffusion Flames in simulating the E-FIELD Flames microgravity results. The focus of this project is to comprehensively simulate the behavior of a small diffusion flame under the influence of an externally applied electric field in zero-gravity. To date, the capability of accurately simulating electric field flames has eluded researchers because the system exhibits dramatic ranges of coupled temporal and spatial scales. Moreover, in earth gravity the hot combustion products are subject to buoyancy effects that are difficult to isolate from those generated by the electric field. This work is an implementation in an existing powerful simulation framework (PeleLM) for this problem using PeleLMeX in order to validate the model and investigate the complex coupled system. The current effort includes establishing the domain of a diffusion coflow burner, examining the boundary conditions, flame geometry and ignition with gravitational forces and also with an electric field applied. A detailed model is used that includes the chemistry of charged ions and chemiluminescent flame intermediates to capture any feedback between ion-driven convection and combustion behavior, and to allow quantitative comparisons with experimental measurements.

coflow flames↗
DOE OSTI2026

Automation of Nanoparticle Synthesis Processes in a Plasma Environment Using LabVIEW

This work presents an automated control system for the synthesis of nanomaterials by plasma-enhanced chemical vapor deposition (PECVD), implemented using the LabVIEW software environment. The main objective of the study is to develop an integrated hardware-software platform that enables sequential control of the key stages of the PECVD process, including vacuum chamber preparation, pressure monitoring, working gas supply, plasma ignition, power matching, cyclic nanomaterial growth, and optical monitoring of nanoparticles in the plasma environment. The use of LabVIEW made it possible to integrate actuator control, experimental parameter acquisition, and realtime process visualization within a single automated system. The automated cycle begins with evacuation of the reaction chamber to a predefined base pressure. Transition to the next stage is permitted only after the specified pressure threshold has been reached, ensuring reproducible initial conditions for each experiment. The program then controls the supply of the working gas through mass flow controllers (MFCs). In this work, two gas-flow control modes were considered: analog control using a 0-5 V voltage signal and digital communication via RS-232 interface. It was shown that the analog approach requires accurate scaling of the control voltage, since applying 5 V corresponds to full-scale opening of the controller and results in the maximum gas flow. In contrast, the RS232 interface enables the gas flow rate to be specified directly in sccm, improving the accuracy, flexibility, and convenience of gas-environment control. After pressure stabilization, LabVIEW initiates RF plasma ignition and executes the RF matching algorithm aimed at minimizing reflected power and improving the stability of the plasma process. A separate software module implements the cyclic nanomaterial growth mode, in which the plasma-on time, plasma duration, and total number of synthesis cycles are predefined. This approach makes it possible to control material accumulation on the substrate and to correlate the process parameters with the morphological characteristics of the resulting nanostructures. The final module of the system is designed for optical monitoring of the nanoparticle cloud density in dusty plasma. For this purpose, the change in the intensity of laser radiation passing through the plasma region is recorded using a photodetector and a Keithley 2401 measuring unit connected to LabVIEW via RS-232 interface. The difference between the initial and modified optical signal intensity is used as a diagnostic parameter characterizing the formation and temporal evolution of nanoparticles. The developed system demonstrates that LabVIEW can be effectively applied not only for the automation of individual instruments, but also for the implementation of a complete digital control cycle for PECVD-based nanomaterial synthesis.

PECVD↗
DOE OSTI2024

A numerical study of ignition and flame development characteristics in GCI combustion using large eddy simulations and chemical explosive mode analysis

Here, this work investigates the ignition and flame development processes of low reactivity fuel combustion under compression ignition conditions based on the large eddy simulation approach. The chemical explosive mode analysis (CEMA) is employed to characterize the local combustion features, including gas-liquid fuel zone, auto-ignition, diffusion-assisted, extinction, cool flame and post-ignition zone, among which auto-ignition and post-ignition are found to play a key role in the overall heat release process. The local flame propagation modes in gasoline compression ignition (GCI) are determined by quantifying the relative magnitude of diffusion/chemistry at a representative progress variable in the pre-ignition zone. The results show that autoignition fronts and deflagration waves exist simultaneously in the ignition and intense high temperature heat release (HTHR) stages, but autoignition fronts dominate. In addition, the chemical kinetic processes of four heat release periods are analyzed. The heat release during the ignition period is found to be dominated by the reactions CH 3 + H (+M) <=> CH 4 (+M) and CH 3 CHO + H <=> CH 2 CHO + H 2 . The reaction CH 2 OH + OH <=> CH 2 O + H 2 O always plays an important role in the heat releases during the other three combustion stages including intense HTHR, moderate HTHR and post-combustion.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2023

Plasma-Coupled Flow Reactor Studies of Low-Temperature Plasma Assisted Kinetics of Methanol Blended with CO2

Ignition technologies based on low-temperature plasmas (LTP) have the potential to operate next generation engines at elevated pressures and increased dilution limits promoting higher efficiencies. From a practical standpoint, research on LTP igniters has shown to enhance combustion and ignition, improve flame stability, and extend the dilution limits of combustion. All of the aforementioned gains are complemented with higher ignition efficiencies. However, the biggest challenge with incorporating this technology into engines is the knowledge gap of how exactly plasma chemistry effects can enhance the basic combustion phenomena. This coupled with the lack of validated kinetic mechanisms for plasma-combustion chemistry is the biggest obstruction to recognize efficient ignition, especially for application relevant fuels and biofuels. In order to comprehensively evaluate the effects of LTP on an oxygenated fuel specific system, this present study examines the kinetics of methanol plasma-assisted pyrolysis and oxidation using a custom-built plasma flow reactor (PFR). Experimental regimes are also further extended to understand the effects of adding CO2 to the mixture and its consequence on reaction kinetics. The PFR is installed with a dielectric-barrier discharge (DBD) configuration to induce LTP into the fuel mixture. Non-equilibrium plasmas are generated by high-voltage pulses (nearing 20 KV) administered by a plasma pulser at high-pulse repetition rates (up to 10 kHz). In order to better understand and isolate plasma chemistry and its effect on neutral chemistry, the experiments were carried out by heavily diluting reactive mixtures in nitrogen at near isothermal conditions. This suppresses the effect of exothermic reactions on chemistry allowing stable intermediates and products to be detected and quantified using ex-situ GC/MS diagnostic methods. Experiments were carried out at 0.5 atm pressure and over a wide range of temperatures from 523 K to 1203 K. Experimental results depicted the enhancement in intermediates production as well as overall lower temperatures required for complete fuel consumption in the plasma specific cases as opposed to their pure thermal counterpart. Formation of oxygenated and nitrile compounds specific to plasma assisted pyrolysis cases illustrated the efficacy of LTP to introduce new reaction pathways accelerating fuel decomposition. Increase in reactivity at lower temperatures is sought to be an effect induced by plasma chemistry postulating the acceleration in intermediates production. The onset of thermal ignition in plasma assisted oxidation is seen 200 K earlier than thermal oxidation highlighting efficient fuel conversion to final byproducts. Enhanced collisional processes afforded by LTP is seen to perturb reaction pathways between oxygenated fuel radicals and N-atoms to alter overall chemical reactivity. New insights into kinetics are gained from this study highlighting governing plasma assisted combustion (PAC) pathways for oxygenated fuel reaction chemistry. The results from this study can be used to develop future mechanisms specific to plasma chemistry which can bridge the mechanistic knowledge gap for LTP ignition so that future engines can adopt LTPs in their design for efficient combustion.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2012

Fuel Effects on Combustion and Emissions of a Direct-Inection Diesel Engine Operating at Moderate to High Engine Speed and Load

It is advantageous to increase the specific power output of diesel engines and to operate them at higher load for a greater portion of a driving cycle to achieve better thermal efficiency and thus reduce vehicle fuel consumption. Such operation is limited by excessive smoke formation at retarded injection timing and high rates of cylinder pressure rise at more advanced timing. Given this window of operation, it is desired to understand the influence of fuel properties such that optimum combustion performance and emissions can be retained over the range of fuels commonly available in the marketplace. It has been shown in previous studies that varying cetane number (CN) of diesel fuel has little effect on ignition delay at high engine load due to the domination of high cylinder temperature on ignition kinetics. The work here experimentally confirms that finding but also shows that emissions and combustion performance vary according to fuel reactivity. Data are examined from a direct-injection single cylinder research engine for eight common diesel fuels including soy-based biodiesel blends at two high load operating points with no exhaust gas recirculation (EGR) and at a moderate load with four levels of EGR. It is shown in the work that at high engine load where combustion is controlled by mixing processes, CN and other fuel properties have little effect on engine performance, although lower CN fuels produce a small increase in noise, smoke and CO emissions. Biodiesel blends increase NOX emissions and decreases CO and smoke emissions at high load, but otherwise have little effect on performance. At moderate load, higher CN fuels are more tolerant to EGR due to their better chemical reactivity at retarded injection timing, but all fuels produce comparable thermal efficiency at advanced combustion phasing regardless of EGR. In contrast to the high load conditions, there was no increase in NOX emissions for biodiesel at the moderate load condition. It is concluded that although higher CN does not significantly alter ignition delay at moderate to high loads it has a dominant influence on the acceptable injection timing range. Apart from CN effects, fuel oxygen content plays an independent role in reducing some emissions. It is therefore recommended that compensation for fuel ignitability and oxygen content be included in combustion control strategies to optimize emissions and performance of future diesel engines.

33 ADVANCED PROPULSION SYSTEMS↗
NASA NTRSDate not supplied

The State of NOS3

The NASA Operational Simulator for Small Satellites (NOS3) showcases some of the Jon McBride Software Testing and Research (JSTAR) laboratories technologies on an open-source platform. NOS3 is a software digital twin providing a virtualized platform inside which you have your traditional flight software, ground software, environmental simulators, and middleware to keep all pieces in sync. NOS3 leverages the core Flight System (cFS), OpenC3 COSMOS, and NASA GSFC’s 42 software as the baseline to which additional research technologies can be developed. Current technologies to be demonstrated include NOS3 Igniter, constellation support, NASA JPL’s SYNOPSIS integration, and NASA GSFC’s OnAir. NOS3 Igniter is a GUI in which you can configure, build, and run your simulation. This along with improvements to the documentation and training available open source aims to reduce the ramp up time with new users and improve accessibility. As constellations introduce another level of complexity, it is important to ensure the baseline design reference mission covers all the basics required and allows users to experiment, understand, and test at all levels of the system. The Science Yield improvement via Onboard Prioritization and Summary of Information Systems (SYNOPSIS) is an open-source tool developed by NASA JPL to enable data prioritization and planning. GSFC’s Onboard Artificial Intelligence Research (OnAIR) enables custom algorithm development written in python to interface with the flight software allowing scientists to develop what they need for the next generation of missions and easily interface back to the traditional flight software. During the presentation, a review and demonstration of the above technologies is planned along with a roadmap.

NOS3↗
DOE OSTI2011

A numerical study comparing the combustion and emission characteristics of biodiesel with petrodiesel.

Combustion and emission characteristics of compression ignition engines strongly depend upon inner-nozzle flow and spray behavior. These processes control the fuel-air mixing, which in turn is critical for the combustion process. Previous studies by us highlighted the differences in the physical and chemical properties of petrodiesel and biodiesel, which significantly altered the inner-nozzle flow and spray structure. The current study is another step in this direction to gain a fundamental understanding on the influence of fuel properties on the combustion and emission characteristics of the compression ignition engine. n-Heptane and methyl butanoate were selected as surrogates for diesel and biodiesel fuels, respectively, because the chemical kinetic pathways were well-understood. Liquid length and flame lift-off length for diesel and biodiesel fuels were validated against data available in the literature. Liquid lengths were always higher for biodiesel because of its higher heat of vaporization, which resulted in increased interplay between spray and combustion processes under all conditions investigated. Ambient air entrainment was also lower for biodiesel mainly because of slower atomization and breakup. The mechanism for flame stabilization is further analyzed by estimating the turbulent burning velocity for both of the fuels. This analysis revealed that neither flame propagation nor isolated ignition kernels upstream and detached from high-temperature regions can be the mechanism for flame stabilization. Flame propagation speeds were observed to be similar for both fuels. Biodiesel predicted lower soot concentrations, which were also reflected in reduced C{sub 2}H{sub 2} mole fractions. Although prompt NO{sub x} was higher for biodiesel, total NO{sub x} was lower because of reduced thermal NO{sub x}. The ignition delay and NO{sub x} emissions predicted by these simulations do not agree with trends reported in the literature; hence, this study highlights the need for better fuel surrogates for diesel and biodiesel fuels.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2019

Impact of fuel and engine operating conditions on efficiency of a heavy duty truck engine running compression ignition mode using energy and exergy analysis

Gasoline compression ignition using a single gasoline-type fuel for direct/port injection has been shown as a method to achieve low temperature combustion with low engine-out NO x and soot emissions and high indicated thermal efficiency. However, key technical barriers to achieving low temperature combustion on multi-cylinder engines include the air handling system (limited amount of exhaust gas recirculation) as well as mechanical engine limitations (e.g. peak pressure rise rate). In light of these limitations, high temperature combustion with reduced amounts of exhaust gas recirculation appears more practical. Previous studies by the authors demonstrated that utilizing port and direct injection of E85 gasoline simultaneously resulted in the best performance and the highest brake thermal efficiency of 47.1%, which was 1.2% higher compared to diesel baseline. For further efficiency improvement, a better understanding of energy and exergy loss mechanisms is required. As such, in this work first and second law thermodynamics analysis were applied to experiments with gasoline compression ignition at an engine speed of 1038 rpm and brake mean effective pressure of 1.4 MPa on a 12.4 L multi-cylinder heavy-duty diesel engine. The impact on the efficiency, losses, and irreversibility with respect to various parameters such as fuel, injection strategy, intake condition, and port injected water mass was quantified. The peak efficiency of ideal cycles and the combined efficiency with a waste heat recovery system were also estimated in this study to assess opportunities for further efficiency gains. It was found that the combustion irreversibility was dominated by the combustion temperature rather than the fuel structure. Despite its highest brake thermal efficiency, E85 gasoline generated the highest exergy destruction due to its lowest combustion temperature. For the same reason, retarding the combustion phasing or adopting a port and direct injection strategy increased the exergy destruction. The combustion duration loss was more notable than the phasing loss and was affected by both the combustion duration and shape of heat release profile. Water port injection increased the exhaust energy, but the available energy dropped significantly attributed to the decrease in the exhaust temperature, rendering waste heat recovery ineffective. The second law analysis serves as a helpful tool in conjunction with the first law analysis to explore pathways to maximize engine efficiency.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2011

The LIFE Laser Design in Context: A Comparison to the State-of-the-Art

The current point design for the LIFE laser leverages decades of solid-state laser development in order to achieve the performance and attributes required for inertial fusion energy. This document provides a brief comparison of the LIFE laser point design to other state-of-the-art solid-state lasers. Table I compares the attributes of the current LIFE laser point design to other systems. the state-of-the-art for single-shot performance at fusion-relevant beamline energies is exemplified by performance observed on the National Ignition Facility. The state-of-the-art for high average power is exemplified by the Northrup Grumman JHPSSL laser. Several items in Table I deal with the laser efficiency; a more detailed discussion of efficiency can be found in reference 5. The electrical-to-optical efficiency of the LIFE design exceeds that of reference 4 due to the availability of higher efficiency laser diode pumps (70% vs. {approx}50% used in reference 4). LIFE diode pumps are discussed in greater detail in reference 6. The 'beam steering' state of the art is represented by the deflection device that will be used in the LIFE laser, not a laser system. Inspection of Table I shows that most LIFE laser attributes have already been experimentally demonstrated. The two cases where the LIFE design is somewhat better than prior experimental work do not involve the development of new concepts: beamline power is increased simply by increasing aperture (as demonstrated by the power/aperture comparison in Table I), and efficiency increases are achieved by employing state-of-the-art diode pumps. In conclusion, the attributes anticipated for the LIFE laser are consistent with the demonstrated performance of existing solid-state lasers.

42 ENGINEERING↗
DOE OSTI2024

Demonstration of hot-spot fuel gain exceeding unity in direct-drive inertial confinement fusion implosions

Irradiating a small capsule containing deuterium and tritium fuel directly with intense laser light causes it to implode, which creates a plasma hot enough to initiate fusion reactions between the fuel nuclei. Here we report on such laser direct-drive experiments and observe that the fusion reactions produce more energy than the amount of energy in the central so-called hot-spot plasma. This condition is identified as having a hot-spot fuel gain greater than unity. A hot-spot fuel gain of around four was previously accomplished at the National Ignition Facility in indirect-drive inertial confinement fusion experiments where the capsule is irradiated by X-rays. In that case, up to 1.9 MJ of laser energy was used, but in contrast, our experiments on the OMEGA laser system require as little as 28 kJ. As the hot-spot fuel gain is predicted to grow with laser energy and target size, our work establishes the direct-drive approach to inertial fusion as a promising path towards burning and ignited plasmas in the laboratory. Additionally, we report a record (direct-drive) fusion yield of 0.9 kJ on OMEGA, which we achieved with thin-ice deuterium–tritium liner targets.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2017

Analysis of operator splitting errors for near-limit flame simulations

High-fidelity simulations of ignition, extinction and oscillatory combustion processes are of practical interest in a broad range of combustion applications. Splitting schemes, widely employed in reactive flow simulations, could fail for stiff reaction–diffusion systems exhibiting near-limit flame phenomena. The present work first employs a model perfectly stirred reactor (PSR) problem with an Arrhenius reaction term and a linear mixing term to study the effects of splitting errors on the near-limit combustion phenomena. Analysis shows that the errors induced by decoupling of the fractional steps may result in unphysical extinction or ignition. The analysis is then extended to the prediction of ignition, extinction and oscillatory combustion in unsteady PSRs of various fuel/air mixtures with a 9-species detailed mechanism for hydrogen oxidation and an 88-species skeletal mechanism for n-heptane oxidation, together with a Jacobian-based analysis for the time scales. The tested schemes include the Strang splitting, the balanced splitting, and a newly developed semi-implicit midpoint method. Results show that the semi-implicit midpoint method can accurately reproduce the dynamics of the near-limit flame phenomena and it is second-order accurate over a wide range of time step size. For the extinction and ignition processes, both the balanced splitting and midpoint method can yield accurate predictions, whereas the Strang splitting can lead to significant shifts on the ignition/extinction processes or even unphysical results. With an enriched H radical source in the inflow stream, a delay of the ignition process and the deviation on the equilibrium temperature are observed for the Strang splitting. On the contrary, the midpoint method that solves reaction and diffusion together matches the fully implicit accurate solution. The balanced splitting predicts the temperature rise correctly but with an over-predicted peak. For the sustainable and decaying oscillatory combustion from cool flames, both the Strang splitting and the midpoint method can successfully capture the dynamic behavior, whereas the balanced splitting scheme results in significant errors.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2010

Demonstration of the Highest Deuterium-Tritium Areal Density Using Multiple-Picket Cryogenic Designs on OMEGA

The performance of triple-picket deuterium-tritium cryogenic target designs on the OMEGA Laser System [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] is reported. These designs facilitate control of shock heating in low-adiabat inertial confinement fusion targets. Areal densities up to 300 mg/cm{sup 2} (the highest ever measured in cryogenic deuterium-tritium implosions) are inferred in the experiments with an implosion velocity {approx}3x10{sup 7} cm/s driven at peak laser intensities of 8x10{sup 14} W/cm{sup 2}. Extension of these designs to ignition on the National Ignition Facility [J. A. Paisner et al., Laser Focus World 30, 75 (1994)] is presented.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗