The Experts below are selected from a list of 81828 Experts worldwide ranked by ideXlab platform
J D Sethian - One of the best experts on this subject based on the ideXlab platform.
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krypton fluoride krf laser driver for inertial Fusion Energy
Fusion Science and Technology, 2013Co-Authors: M F Wolford, J D Sethian, M C Myers, F Hegeler, J L Giuliani, Stephen P ObenschainAbstract:AbstractThe United States Naval Research Laboratory (NRL) is developing the krypton fluoride (KrF) laser technology for a direct drive laser inertial Fusion Energy (IFE) power plant. The overall projected wall plug efficiency for KrF laser system is ~7%, including thermal management and optical losses. There are two KrF lasers at NRL. The first, Nike, provides up to 3 kJ of laser light per shot for experimental research in KrF laser-target interactions. The Electra Laser at NRL is a repetitively pulsed electron beam pumped 700 Joule KrF laser facility. The objective with Electra is to develop technologies to meet the IFE requirements for repetition rate, efficiency, and durability. Electra produces over 750 Joules in oscillator mode. Based on experiments, there is expected to be virtually no degradation in the laser focal profile, even at 5 Hz, high efficiency operation. Progress in durability has lead to achievement of KrF laser runs for 10 continuous hours at 2.5 Hz (90,000 shots) and 100 minutes at 5 H...
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laser requirements for a laser Fusion Energy power plant
High Power Laser Science and Engineering, 2013Co-Authors: S E Bodner, A J Schmitt, J D SethianAbstract:We will review some of the requirements for a laser that would be used with a laser Fusion Energy power plant, including frequency, spatial beam smoothing, bandwidth, temporal pulse shaping, efficiency, repetition rate, and reliability. The lowest risk and optimum approach uses a krypton fluoride gas laser. A diode-pumped solid-state laser is a possible contender.
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the science and technologies for Fusion Energy with lasers and direct drive targets
IEEE Transactions on Plasma Science, 2010Co-Authors: J D Sethian, M F Wolford, M C Myers, J L Giuliani, Stephen P Obenschain, R H Lehmberg, A J Schmitt, D G Colombant, J L Weaver, F HegelerAbstract:We are carrying out a multidisciplinary multi-institutional program to develop the scientific and technical basis for inertial Fusion Energy (IFE) based on laser drivers and direct-drive targets. The key components are developed as an integrated system, linking the science, technology, and final application of a 1000-MWe pure-Fusion power plant. The science and technologies developed here are flexible enough to be applied to other size systems. The scientific justification for this work is a family of target designs (simulations) that show that direct drive has the potential to provide the high gains needed for a pure-Fusion power plant. Two competing lasers are under development: the diode-pumped solid-state laser (DPPSL) and the electron-beam-pumped krypton fluoride (KrF) gas laser. This paper will present the current state of the art in the target designs and lasers, as well as the other IFE technologies required for Energy, including final optics (grazing incidence and dielectrics), chambers, and target fabrication, injection, and tracking technologies. All of these are applicable to both laser systems and to other laser IFE-based concepts. However, in some of the higher performance target designs, the DPPSL will require more Energy to reach the same yield as with the KrF laser.
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electron beam pumped krypton fluoride lasers for Fusion Energy
Proceedings of the IEEE, 2004Co-Authors: J D Sethian, M F Wolford, M C Myers, F Hegeler, J L Giuliani, Stephen P Obenschain, M Friedman, R H Lehmberg, P Kepple, R V SmilgysAbstract:High-Energy electron beam pumped krypton fluoride (KrF) gas lasers are an attractive choice for inertial Fusion Energy (IFE). Their short wavelength and demonstrated high beam uniformity optimizes the laser-target physics, and their pulsed power technology scales to a large system. This paper presents the principals of this type of laser and the progress toward developing technologies that can meet the IFE requirements for repetition rate (5 Hz), efficiency (>6%), and durability (>3/spl times/10/sup 8/ shots). The Electra laser at the Naval Research Laboratory (NRL) has produced >500 J of laser light in short 5-Hz bursts. Research on Electra and the NRL Nike laser (3000 J, single shot) has shown that the overall efficiency should be greater than 7%. This is based on recent advances in electron beam stabilization and transport, electron beam deposition, KrF laser physics, and pulsed power. The latter includes the development of a new solid-state laser triggered switch that will be the basis for a pulsed power system that can meet the IFE requirements for efficiency, durability, and cost. The major remaining challenge is to develop long-lived hibachi foils (e-beam transmission windows). Based on recent experiments, this may be achievable by periodically deflecting the laser gas.
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Fusion Energy with lasers direct drive targets and dry wall chambers
Nuclear Fusion, 2003Co-Authors: J D Sethian, M C Myers, J L Giuliani, Stephen P Obenschain, M Friedman, R H Lehmberg, P Kepple, A J Schmitt, D G Colombant, J H GardnerAbstract:A coordinated, focused effort is underway to develop Laser Inertial Fusion Energy. The key components are developed in concert with one another and the science and engineering issues are addressed concurrently. Recent advances include: target designs have been evaluated that show it could be possible to achieve the high gains (>100) needed for a practical Fusion system.These designs feature a low-density CH foam that is wicked with solid DT and over-coated with a thin high-Z layer. These results have been verified with three independent one-dimensional codes, and are now being evaluated with two- and three-dimensional codes. Two types of lasers are under development: Krypton Fluoride (KrF) gas lasers and Diode Pumped Solid State Lasers (DPSSL). Both have recently achieved repetitive 'first light', and both have made progress in meeting the Fusion Energy requirements for durability, efficiency, and cost. This paper also presents the advances in development of chamber operating windows (target survival plus no wall erosion), final optics (aluminium at grazing incidence has high reflectivity and exceeds the required laser damage threshold), target fabrication (demonstration of smooth DT ice layers grown over foams, batch production of foam shells, and appropriate high-Z overcoats), and target injection (new facility for target injection and tracking studies).
W F Krupke - One of the best experts on this subject based on the ideXlab platform.
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recent advances and challenges for diode pumped solid state lasers as an inertial Fusion Energy driver candidate
IEEE NPSS Symposium on Fusion Engineering, 1997Co-Authors: S A Payne, R J Beach, C Bibeau, C A Ebbers, M A Emanual, Eric C Honea, W F Krupke, C D Marshall, C Orth, H T PowellAbstract:We discuss how solid-state laser technology can serve in the interests of Fusion Energy beyond the goals of the National Ignition Facility (NIF), which is now being constructed to ignite a deuterium-tritium target to Fusion conditions in the laboratory for the first time. We think that advanced solid-state laser technology can offer the repetition-rate and efficiency needed to drive a Fusion power plant, in contrast to the single-shot character of NIF. As discussed below, we propose that a gas-cooled, diode-pumped Yb:S-FAP laser can provide new paradigm for Fusion laser technology leading into the next century.
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a diode pumped solid state laser driver for inertial Fusion Energy
Nuclear Fusion, 1996Co-Authors: C D Orth, S A Payne, W F KrupkeAbstract:A comprehensive conceptual design for a diode pumped solid state laser (DPSSL) as a driver for an inertial Fusion Energy (IFE) power plant is presented. This design is based on recent technical advances that offer potential solutions to difficulties previously associated with the use of a laser for IFE applications. The design was selected by using a systems analysis code that optimizes a DPSSL configuration by minimizing the calculated cost of electricity (COE). The code contains the significant physics relevant to the DPSSL driver, but treats the target chamber and balance of plant costs generically using scaling relations published for the Sombrero KrF laser concept. The authors describe the physics incorporated in the code, predict DPSSL performance and its variations with changes in the major parameters, discuss IFE economics and technical risk, and identify the high leverage development efforts that can make DPSSL driven IFE plants more economically competitive. It is believed that this study is a significant advance over previous conceptual studies of DPSSLs for IFE because it incorporates a new cost effective gain medium, applies a potential solution to the `final optics` problem, and considers the laser physics in substantially greater detail. The result is the introduction of an option for an IFE driver that has relatively low development costs and that builds upon the mature laser technology base already developed for Nova and being developed for the proposed National Ignition Facility. The baseline design of the paper has a product of laser efficiency and target gain of ηG~6.6 and a COE of 8.6 cents/kW.h for a 1 GW(e) plant with a target gain of 76 at 3.7 MJ. Higher ηG(11) and lower COEs (6.6 cents/kW.h) can be achieved with target gains twice as high
R W Petzoldt - One of the best experts on this subject based on the ideXlab platform.
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a cost effective target supply for inertial Fusion Energy
Nuclear Fusion, 2004Co-Authors: D T Goodin, N B Alexander, C R Gibson, A Nobile, C L Olson, L C Brown, D T Frey, R Gallix, James L Maxwell, R W PetzoldtAbstract:A central feature of an inertial Fusion Energy (IFE) power plant is a target that has been compressed and heated to Fusion conditions by the Energy input of the driver. This is true whether the driver is a laser system, heavy ion beams or Z-pinch system. The IFE target fabrication, injection and tracking programmes are focusing on methods that will scale to mass production. We are working closely with target designers, and power plant systems specialists, to make specifications and material selections that will satisfy a wide range of required and desirable target characteristics. One-of-a-kind capsules produced for today’s inertial confinement Fusion experiments are estimated to cost about US$2500 each. Design studies of cost-effective power production from laser and heavy-ion driven IFE have suggested a cost goal of about $0.25–0.30 for each injected target (corresponding to ∼10% of the ‘electricity value’ in a target). While a four orders of magnitude cost reduction may seem at first to be nearly impossible, there are many factors that suggest this is achievable. This paper summarizes the design, specifications, requirements and proposed manufacturing processes for the future for laser Fusion, heavy ion Fusion and Z-pinch driven targets. These target manufacturing processes have been developed—and are proposed—based on the unique materials science and technology programmes that are ongoing for each of the target concepts. We describe the paradigm shifts in target manufacturing methodologies that will be needed to achieve orders of magnitude reductions in target costs, and summarize the results of ‘nth-of-a-kind’ plant layouts and cost estimates for future IFE power plant fuelling. These engineering studies estimate the cost of the target supply in a Fusion economy, and show that costs are within the range of commercial feasibility for electricity production.
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direct drive target survival during injection in an inertial Fusion Energy power plant
Nuclear Fusion, 2002Co-Authors: R W Petzoldt, D T Goodin, A Nikroo, Elizabeth H Stephens, Nathan P Siegel, N B Alexander, A R Raffray, T K Mau, M S Tillack, F NajmabadiAbstract:In inertial Fusion Energy (IFE) power plant designs, the fuel is a spherical layer of frozen DT contained in a target that is injected at high velocity into the reaction chamber. For direct drive, typically laser beams converge at the centre of the chamber (CC) to compress and heat the target to Fusion conditions. To obtain the maximum Energy yield from the Fusion reaction, the frozen DT layer must be at about 18.5 K and the target must maintain a high degree of spherical symmetry and surface smoothness when it reaches the CC. During its transit in the chamber the cryogenic target is heated by radiation from the hot chamber wall. The target is also heated by convection as it passes through the rarefied fill-gas used to control chamber wall damage by x-rays and debris from the target explosion. This article addresses the temperature limits at the target surface beyond which target uniformity may be damaged. It concentrates on direct drive targets because fuel warm up during injection is not currently thought to be an issue for present indirect drive designs and chamber concepts. Detailed results of parametric radiative and convective heating calculations are presented for direct-drive targets during injection into a dry-wall reaction chamber. The baseline approach to target survival utilizes highly reflective targets along with a substantially lower chamber wall temperature and fill-gas pressure than previously assumed. Recently developed high-Z material coatings with high heat reflectivity are discussed and characterized. The article also presents alternate target protection methods that could be developed if targets with inherent survival features cannot be obtained within a reasonable time span.
A J Bayramian - One of the best experts on this subject based on the ideXlab platform.
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comparison of nd phosphate glass yb yag and yb s fap laser beamlines for laser inertial Fusion Energy life invited
Optical Materials Express, 2011Co-Authors: A C Erlandson, R J Beach, Sal Aceves, A J Bayramian, Charles D Boley, Amber L Bullington, J A Caird, R J Deri, A M Dunne, Daniel L FlowersAbstract:We present the results of performance modeling of diode-pumped solid state laser beamlines designed for use in Laser Inertial Fusion Energy (LIFE) power plants. Our modeling quantifies the efficiency increases that can be obtained by increasing peak diode power and reducing pump-pulse duration, to reduce decay losses. At the same efficiency, beamlines that use laser slabs of Yb:YAG or Yb:S-FAP require lower diode power than beamlines that use laser slabs of Nd:phosphate glass, since Yb:YAG and Yb:S-FAP have longer storage lifetimes. Beamlines using Yb:YAG attain their highest efficiency at a temperature of about 200K. Beamlines using Nd:phosphate glass or Yb:S-FAP attain high efficiency at or near room temperature.
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compact efficient laser systems required for laser inertial Fusion Energy
Fusion Science and Technology, 2011Co-Authors: A J Bayramian, Sal Aceves, T Anklam, K L Baker, Erlan S Bliss, Charles D Boley, Amber L Bullington, J A Caird, D Chen, R J DeriAbstract:This paper presents our conceptual design for laser drivers used in Laser Inertial Fusion Energy (LIFE) power plants. Although we have used only modest extensions of existing laser technology to en...
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compact efficient laser systems required for laser inertial Fusion Energy
Fusion Science and Technology, 2011Co-Authors: A J Bayramian, Sal Aceves, T Anklam, K L Baker, Erlan S Bliss, Charles D Boley, Amber L Bullington, J A Caird, D Chen, R J DeriAbstract:AbstractThis paper presents our conceptual design for laser drivers used in Laser Inertial Fusion Energy (LIFE) power plants. Although we have used only modest extensions of existing laser technology to ensure near-term feasibility, predicted performance meets or exceeds plant requirements: 2.2 MJ pulse Energy produced by 384 beamlines at 16 Hz, with 18% wall-plug efficiency. High reliability and maintainability are achieved by mounting components in compact line-replaceable units that can be removed and replaced rapidly while other beamlines continue to operate, at up to ˜13% above normal Energy, to compensate for neighboring beamlines that have failed. Statistical modeling predicts that laser-system availability can be greater than 99% provided that components meet reasonable mean-time-between-failure specifications.
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the mercury project a high average power gas cooled laser for inertial Fusion Energy development
Fusion Science and Technology, 2007Co-Authors: A J Bayramian, C Bibeau, J A Caird, P Armstrong, E Ault, Raymond J Beach, R Campbell, B Chai, Jay W Dawson, C A EbbersAbstract:Hundred-joule, kilowatt-class lasers based on diode-pumped solid-state technologies, are being developed worldwide for laser-plasma interactions and as prototypes for Fusion Energy drivers. The goal of the Mercury Laser Project is to develop key technologies within an architectural framework that demonstrates basic building blocks for scaling to larger multi-kilojoule systems for inertial Fusion Energy (IFE) applications. Mercury has requirements that include: scalability to IFE beamlines, 10 Hz repetition rate, high efficiency, and 10 9 shot reliability. The Mercury laser has operated continuously for several hours at 55 J and 10 Hz with fourteen 4 x 6 cm 2 ytterbium doped strontium fluoroapatite amplifier slabs pumped by eight 100 kW diode arrays. A portion of the output 1047 nm was converted to 523 nm at 160 W average power with 73% conversion efficiency using yttrium calcium oxy-borate (YCOB).
D T Goodin - One of the best experts on this subject based on the ideXlab platform.
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target tracking and engagement for inertial Fusion Energy a tabletop demonstration
Fusion Science and Technology, 2007Co-Authors: L Carlson, D T Goodin, N B Alexander, M S Tillack, Thomas Lorentz, Jon Spalding, G W Flint, Ronald W PetzoldtAbstract:In the High Average Power Laser program, we have developed an integrated target tracking and engagement system designed to track an inertial Fusion Energy target traveling 50-100 m/s in three dimensions and to steer driver beams so as to engage it with ±20 μm accuracy. The system consists of separate axial and transverse detection techniques to pre-steer individual beamlet mirrors, and a final fine-correction technique using a short-pulse laser "glint" from the target itself. Transverse tracking of the target uses the Poisson spot diffraction phenomenon, which lies exactly on axis to the centroid of the target. The spot is imaged on a digital video camera and its centroid is calculated in ∼10 ms with 5 μm precision. In our tabletop demonstration, we have been able to continuously track a target falling at 5 m/s and provide a fast steering mirror with steering commands. We are on the verge of intercepting the target on-the-fly and of verifying the accuracy of engagement. Future work entails combining transverse tracking, axial tracking, triggering and the final "glint" system. We also will implement a verification technique that confirms successful target engagement with a simulated driver beam. Results and integration progress are reported.
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a cost effective target supply for inertial Fusion Energy
Nuclear Fusion, 2004Co-Authors: D T Goodin, N B Alexander, C R Gibson, A Nobile, C L Olson, L C Brown, D T Frey, R Gallix, James L Maxwell, R W PetzoldtAbstract:A central feature of an inertial Fusion Energy (IFE) power plant is a target that has been compressed and heated to Fusion conditions by the Energy input of the driver. This is true whether the driver is a laser system, heavy ion beams or Z-pinch system. The IFE target fabrication, injection and tracking programmes are focusing on methods that will scale to mass production. We are working closely with target designers, and power plant systems specialists, to make specifications and material selections that will satisfy a wide range of required and desirable target characteristics. One-of-a-kind capsules produced for today’s inertial confinement Fusion experiments are estimated to cost about US$2500 each. Design studies of cost-effective power production from laser and heavy-ion driven IFE have suggested a cost goal of about $0.25–0.30 for each injected target (corresponding to ∼10% of the ‘electricity value’ in a target). While a four orders of magnitude cost reduction may seem at first to be nearly impossible, there are many factors that suggest this is achievable. This paper summarizes the design, specifications, requirements and proposed manufacturing processes for the future for laser Fusion, heavy ion Fusion and Z-pinch driven targets. These target manufacturing processes have been developed—and are proposed—based on the unique materials science and technology programmes that are ongoing for each of the target concepts. We describe the paradigm shifts in target manufacturing methodologies that will be needed to achieve orders of magnitude reductions in target costs, and summarize the results of ‘nth-of-a-kind’ plant layouts and cost estimates for future IFE power plant fuelling. These engineering studies estimate the cost of the target supply in a Fusion economy, and show that costs are within the range of commercial feasibility for electricity production.
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direct drive target survival during injection in an inertial Fusion Energy power plant
Nuclear Fusion, 2002Co-Authors: R W Petzoldt, D T Goodin, A Nikroo, Elizabeth H Stephens, Nathan P Siegel, N B Alexander, A R Raffray, T K Mau, M S Tillack, F NajmabadiAbstract:In inertial Fusion Energy (IFE) power plant designs, the fuel is a spherical layer of frozen DT contained in a target that is injected at high velocity into the reaction chamber. For direct drive, typically laser beams converge at the centre of the chamber (CC) to compress and heat the target to Fusion conditions. To obtain the maximum Energy yield from the Fusion reaction, the frozen DT layer must be at about 18.5 K and the target must maintain a high degree of spherical symmetry and surface smoothness when it reaches the CC. During its transit in the chamber the cryogenic target is heated by radiation from the hot chamber wall. The target is also heated by convection as it passes through the rarefied fill-gas used to control chamber wall damage by x-rays and debris from the target explosion. This article addresses the temperature limits at the target surface beyond which target uniformity may be damaged. It concentrates on direct drive targets because fuel warm up during injection is not currently thought to be an issue for present indirect drive designs and chamber concepts. Detailed results of parametric radiative and convective heating calculations are presented for direct-drive targets during injection into a dry-wall reaction chamber. The baseline approach to target survival utilizes highly reflective targets along with a substantially lower chamber wall temperature and fill-gas pressure than previously assumed. Recently developed high-Z material coatings with high heat reflectivity are discussed and characterized. The article also presents alternate target protection methods that could be developed if targets with inherent survival features cannot be obtained within a reasonable time span.
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developing the basis for target injection and tracking in inertial Fusion Energy power plants
Fusion Engineering and Design, 2002Co-Authors: D T Goodin, Nathan P Siegel, C R Gibson, Ronald W Petzoldt, L Thompson, A Nobile, G E Besenbruch, K R SchultzAbstract:Abstract Fueling of a commercial Inertial Fusion Energy (IFE) power plant consists of supplying about 500,000 Fusion targets each day. The most challenging type of target in this regard is for laser-driven, direct drive IFE. Spherical capsules with cryogenic DT fuel must be injected into the center of a reaction chamber operating at temperatures as high as 1500 °C and possibly containing as much as 0.5 Torr of xenon fill gas. The DT layer must remain highly symmetric, have a smooth inner ice surface finish, and reach the chamber center at a temperature of about 18.5 K. This target must be positioned at the center of the chamber with a placement accuracy of ±5 mm. The accuracy of alignment of the laser driver beams and the target in its final position must be within ±20 μm. All this must be repeated six times per second. The method proposed to meet these requirements is injecting the targets into the reaction chamber at high speed (∼400 m/s), tracking them, and hitting them on the fly with steerable driver beams. The challenging scientific and technological issues associated with this task are being addressed through a combination of analyses, modeling, materials property measurements, and demonstration tests with representative injection equipment. Measurements of relevant DT properties are planned at Los Alamos National Laboratory. An experimental target injection and tracking system is now being designed to support the development of survivable targets and demonstrate successful injection scenarios. Analyses of target heating are underway. Calculations have shown that the direct drive target must have a highly reflective outer surface to prevent excess heating by thermal radiation. In addition, heating by hot chamber fill gas during injection far outweighs the thermal radiation. It is concluded that the dry-wall, gas-filled reaction chambers must have gas pressures less than previously assumed in order to prevent excessive heating in the current direct drive target designs. An integrated power plant systems study to address this issue has been initiated.
