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The role of the NIF in the development of inertial fusion energy

Description: Recent decisions by DOE to proceed with the National Ignition Facility (NIF) and the first half of the Induction Systems Linac Experiments (ILSE) can provide the scientific basis for inertial fusion ignition and high-repetition heavy-ion driver physics, respectively. Both are critical to Inertial Fusion Energy (IFE). A conceptual design has been completed for a 1.8-MJ, 500-TW, 0.35-{micro}m-solid-state laser system, the NIF. The NIF will demonstrate inertial fusion ignition and gain for national security applications, and for IFE development. It will support science applications using high-power lasers. The demonstration of inertial fusion ignition and gain, along with the parallel demonstration of the feasibility of an efficient, high-repetition-rate driver, would provide the basis for a follow-on Engineering Test Facility (ETF) identified in the National Energy Policy Act of 1992. The ETF would provide an integrated testbed for the development and demonstration of the technologies needed for IFE power plants. In addition to target physics of ignition, the NIF will contribute important data on IFE target chamber issues, including neutron damage, activation, target debris clearing, operational experience in many areas prototypical to future IFE power plants, and an opportunity to provide tests of candidate low-cost IFE targets and injection systems. An overview of the NIF design and the target area environments relevant to conducting IFE experiments are described in Section 2. In providing this basic data for IFE, the NIF will provide confidence that an ETF can be successful in the integration of drivers, target chambers, and targets for IFE.
Date: March 16, 1995
Creator: Logan, B.G.
Partner: UNT Libraries Government Documents Department

Relevance of the U.S. National Ignition Facility for driver and target options to next-step inertial fusion test facilities

Description: Achievement of inertial fusion ignition and energy gain in the proposed U.S. National Ignition Facility is a prerequisite for decisions to build next-step U.S. inertial fusion facilities for either high yield or high pulse-rate. There are a variety of target and driver options for such next-step inertial fusion test facilities, and this paper discusses possible ways that the NIF, using a 1.8 MJ glass laser in both direct and indirect-drive configurations, can provide target physics data relevant to several next-step facility options. Next step facility options include the Engineering Test Facility (ETF), which needs several-Hz pulse-rates for testing relevant to Inertial Fusion Energy (IFE) development. An option for high yield, called the Laboratory Microfusion Facility (LMF), does not require such high pulse-rates, but may still benefit from driver technologies capable of much higher shot rates than possible with glass lasers. A high-pulse-rate driver could also be used for a combined ETF/LMF facility, driving multiple target chambers with a common driver. Driver technologies that could support high-pulse rates for next-step options include heavy-ion and light-ion accelerators, diode-pumped solid-state lasers (DPSSL), and krypton-flouride gas lasers. The NIF could be used to provide important data for IFE in generic areas of target chamber damage and materials responses, neutron activation and heating, tritium recovery and safety, and in performance tests of prototypical IFE targets and injection systems. In the study of ignition in both direct and indirect-drive, the NIF would explore generic ICF fuel capsule implosion physics common to all driver and target options for next-step facilities. In the following, we point out specific ways in which the NIF could be used to study target physics specifically relevant to the above-mentioned driver options for such next-step facilities, as well as how the NIF laser system itself could be relevant to the DPSSL option.
Date: April 10, 1995
Creator: Logan, B.G.
Partner: UNT Libraries Government Documents Department

Exploring a unique vision for heavy ion fusion

Description: A quest for more efficient beam-to-fuel energy coupling via polar direct drive (30% overall), to enable: (1) Self-T-breeding, self-neutron-energy-absorbing, large {pi}r, T-Lean targets {at} < 4 MJ driver energies; (2) Efficient fusion energy coupling into plasma for direct MHD conversion with moderate yields < 1 GJ; (3) Balance-of-plant costs 10X lower than steam cycle (e.g., < 80 $/kWe instead of 800 $/kWe); (4) CoE low enough (<3 cts/kWehr) for affordable water and H{sub 2} fuel for 10 B people on a hot planet; and (5) Enough fissile fuel production for 38 LWR's per GW{sub fusion} if uranium gets too expensive meantime.
Date: August 6, 2007
Creator: LOGAN, B.G. & Logan, B.G.
Partner: UNT Libraries Government Documents Department

Beam charge and current neutralization of high-charge-state heavy ions

Description: High-charge-state heavy-ions may reduce the accelerator voltage and cost of heavy-ion inertial fusion drivers, if ways can be found to neutralize the space charge of the highly charged beam ions as they are focused to a target in a fusion chamber. Using 2-D Particle-In- Cell simulations, we have evaluated the effectiveness of two different methods of beam neutralization: (1) by redistribution of beam charge in a larger diameter, preformed plasma in the chamber, and (2), by introducing a cold-electron-emitting source within the beam channel at the beam entrance into the chamber. We find the latter method to be much more effective for high-charge-state ions.
Date: October 29, 1997
Creator: Logan, B.G. & Callahan, D.A.
Partner: UNT Libraries Government Documents Department

Inertial fusion energy development approaches for direct and indirect-drive

Description: Consideration of different driver and target requirements for inertial fusion energy (IFE) power plants together with the potential energy gains of direct and indirect-drive targets leads to different optimal combinations of driver and target options for each type of target. In addition, different fusion chamber concepts are likely to be most compatible with these different driver and target combinations. For example, heavy-ion drivers appear to be well matched to indirect=drive targets with all-liquid-protected-wall chambers requiring two-sided illuminations, while diode-pumped, solid- state laser drivers are better matched to direct-drive targets with chambers using solid walls or flow-guiding structures to allow spherically symmetric illuminations. R&D on the critical issues of drivers, targets, and chambers for both direct and indirect-drive options should be pursued until the ultimate gain of either type of target for IFE is better understood.
Date: August 20, 1996
Creator: Logan, B.G.; Lindl, J.D. & Meier, W.R.
Partner: UNT Libraries Government Documents Department

Concept for high-charge-state ion induction accelerators

Description: This work describes a particular concept for ion induction linac accelerators using high-charge-state ions produced by an intense, short pulse laser, and compares the costs of a modular driver system producing 6.5 MJ for a variety of ion masses and charge states using a simple but consistent cost model.
Date: November 15, 1996
Creator: Logan, B.G.; Perry, M.D. & Caporaso, G.J.
Partner: UNT Libraries Government Documents Department

Nonuniformity for rotated beam illumination in directly driven heavy-ion fusion

Description: A key issue in heavy-ion beam inertial confinement fusion is target interaction, especially implosion symmetry. In this paper the 2D beam irradiation nonuniformity on the surface of a spherical target is studied. This is a first step to studies of 3D dynamical effects on target implosion. So far non-rotated beams have been studied. Because normal incidence may increase Rayleigh-Taylor instabilities, it has been suggested to rotate beams (to increase average uniformity) and hit the target tangentially. The level of beam irradiation uniformity, beam spill and normal incidence is calculated in this paper. In Mathematica the rotated beams are modeled as an annular integrated Gaussian beam. To simplify the chamber geometry, the illumination scheme is not a 4{pi} system, but the beams are arranged on few polar rings around the target. The position of the beam spot rings is efficiently optimized using the analytical model. The number of rings and beams, rotation radii and widths are studied to optimize uniformity and spilled intensity. The results demonstrate that for a 60-beam system on four rings Peak-To-Valley nonuniformities of under 0.5% are possible.
Date: January 2, 2009
Creator: Runge, J. & Logan, B.G.
Partner: UNT Libraries Government Documents Department

Overview of US heavy-ion fusion progress and plans

Description: Significant experimental and theoretical progress has been made in the U.S. heavy ion fusion program on high-current sources, transport, final focusing, chambers and targets for inertial fusion energy (IFE) driven by induction linac accelerators seek to provide the scientific and technical basis for the Integrated Beam Experiment (IBX), an integrated source-to-target physics experiment recently included in the list of future facilities planned by the U.S. Department of Energy. To optimize the design of IBX and future inertial fusion energy drivers, current HIF-VNL research is addressing several key issues (representative, not inclusive): gas and electron cloud effects which can exacerbate beam loss at high beam perveance and magnet aperture fill factors; ballistic neutralized and assisted-pinch focusing of neutralized heavy ion beams; limits on longitudinal compression of both neutralized and un-neutralized heavy ion bunches; and tailoring heavy ion beams for uniform target energy deposition for high energy density physics (HEDP) studies.
Date: June 1, 2004
Creator: Logan, B.G.
Partner: UNT Libraries Government Documents Department

Direct drive heavy-ion-beam inertial fusion at high coupling efficiency

Description: Issues with coupling efficiency, beam illumination symmetry, and Rayleigh-Taylor instability are discussed for spherical heavy-ion-beam-driven targets with and without hohlraums. Efficient coupling of heavy-ion beams to compress direct-drive inertial fusion targets without hohlraums is found to require ion range increasing several-fold during the drive pulse. One-dimensional implosion calculations using the LASNEX inertial confinement fusion target physics code shows the ion range increasing fourfold during the drive pulse to keep ion energy deposition following closely behind the imploding ablation front, resulting in high coupling efficiencies (shell kinetic energy/incident beam energy of 16% to 18%). Ways to increase beam ion range while mitigating Rayleigh-Taylor instabilities are discussed for future work.
Date: May 16, 2008
Creator: Logan, B.G.; Perkins, L.J. & Barnard, J.J.
Partner: UNT Libraries Government Documents Department

Acceleration of compact toruses and fusion applications

Description: The Compact Torus (Spheromak-type) is a near ideal plasma confinement configuration for acceleration. The fields are mostly generated by internal plasma currents, plasma confinement is toroidal, and the compact torus exhibits resiliency and stability in virtue of the ``rugged`` helicity invariant. Based on these considerations we are developing a coaxial rail-gun type Compact Torus Accelerator (CTA). In the CTA, the CT ring is formed between coaxial electrodes using a magnetized Marshall gun, it is quasistatically ``precompressed`` in a conical electrode section for inductive energy storage, it is accelerated in a straight-coaxial electrode section as in a conventional rail-gun, and it is focused to small size and high energy and power density in a final ``focus`` cone section. The dynamics of slow precompression and acceleration have been demonstrated experimentally in the RACE device with results in good agreement with 2-D MHD code calculations. CT plasma rings with 100 {micro}gms mass have been accelerated to 40 Kj kinetic energy at 20% efficiency with final velocity = 1 X 10{sup 8} cm/s (= 5 KeV/H{sup +}). Preliminary focus tests exhibi dynamics of radius compression, deceleration, and bouncing. Compression ratios of 2-3 have been achieved. A scaled-up 10-100 MJ CTA is predicted to achieve a focus radius of several cm to deliver = 30 MJ ring kinetic energy in 5-10 nsec. This is sufficient energy, power, and power density to enable the CTA to act as a high efficiency, low cost ICF driver. Alternatively, the focused CT can form the basis for an magnetically insulated, inertial confinement fusion (MICF) system. Preliminary calculations of these fusion systems will be discussed.
Date: October 11, 1990
Creator: Hartman, C.W.; Eddleman, J.L.; Hammer, J.H.; Logan, B.G.; McLean, H.S. & Molvik, A.W.
Partner: UNT Libraries Government Documents Department

Design choices for the integrated beam experiment (IBX)

Description: Over the next three years the research program of the Heavy Ion Fusion Virtual National Laboratory (HIF-VNL), a collaboration among LBNL, LLNL, and PPPL, is focused on separate scientific experiments in the injection, transport and focusing of intense heavy ion beams at currents from 100 mA to 1 A. As a next major step in the HIF-VNL program, they aim for a complete ''source-to-target'' experiment, the Integrated Beam Experiment (IBX). By combining the experience gained in the current separate beam experiments IBX would allow the integrated scientific study of the evolution of a high current ({approx}1 A) single heavy ion beam through all sections of a possible heavy ion fusion accelerator: the injection, acceleration, compression, and beam focusing. This paper describes the main parameters and technology choices of the proposed IBX experiment. IBX will accelerate singly charged potassium or argon ion beams up to 10 MeV final energy and a longitudinal beam compression ratio of 10, resulting in a beam current at the target of more than 10 Amperes. The different accelerator cell design options are described in detail, in particular the induction core modules incorporating either room temperature pulsed focusing-magnets or superconducting magnets.
Date: May 2003
Creator: Leitner, M. A.; Celata, C. M.; Lee, E. P.; Logan, B. G.; Sabbi, G.; Waldron, W. L. et al.
Partner: UNT Libraries Government Documents Department

ECR plasma source for heavy ion beam charge neutralization

Description: Highly ionized plasmas are being considered as a medium for charge neutralizing heavy ion beams in order to focus beyond the space-charge limit. Calculations suggest that plasma at a density of 1-100 times the ion beam density and at a length {approx} 0.1-2 m would be suitable for achieving a high level of charge neutralization. An ECR source has been built at the Princeton Plasma Physics Laboratory (PPPL) to support a joint Neutralized Transport Experiment (NTX) at the Lawrence Berkeley National Laboratory (LBNL) to study ion beam neutralization with plasma. The ECR source operates at 13.6 MHz and with solenoid magnetic fields of 1-10 gauss. The goal is to operate the source at pressures {approx} 10{sup -6} Torr at full ionization. The initial operation of the source has been at pressures of 10{sup -4}-10{sup -1} Torr. Electron densities in the range of 10{sup 8}-10{sup 11} cm{sup -3} have been achieved. Low-pressure operation is important to reduce ion beam ionization. A cusp magnetic field has been installed to improve radial confinement and reduce the field strength on the beam axis. In addition, axial confinement is believed to be important to achieve lower-pressure operation. To further improve breakdown at low pressure, a weak electron source will be placed near the end of the ECR source.
Date: May 1, 2002
Creator: Efthimion, P.C.; Gilson, E.; Grisham, L.; Kolchin, P.; Davidson, E.C.; Yu, S.S. et al.
Partner: UNT Libraries Government Documents Department

The Heavy Ion Fusion Program in the U.S.A.

Description: Inertial fusion energy research has enjoyed increased interest and funding. This has allowed expanded programs in target design, target fabrication, fusion chamber research, target injection and tracking, and accelerator research. The target design effort examines ways to minimize the beam power and energy and increase the allowable focal spot size while preserving target gain. Chamber research for heavy ion fusion emphasizes the use of thick liquid walls to serve as the coolant, breed tritium, and protect the structural wall from neutrons, photons, and other target products. Several small facilities are now operating to model fluid chamber dynamics. A facility to study target injection and tracking has been built and a second facility is being designed. Improved economics is an important goal of the accelerator research. The accelerator research is also directed toward the design of an Integrated Research Experiment (IRE). The IRE is being designed to accelerate ions to >100 MeV, enabling experiments in beam dynamics, focusing, and target physics. Activities leading to the IRE include ion source development and a High Current Experiment (HCX) designed to transport and accelerate a single beam of ions with a beam current of approximately 1 A, the initial current required for each beam of a fusion driver. In terms of theory, the program is developing a source-to-target numerical simulation capability. The goal of the entire program is to enable an informed decision about the promise of heavy ion fusion in about a decade.
Date: October 3, 2000
Creator: Bangerter, R.O.; Davidson, R.C.; Herrmannsfeldt, W.B.; Lindl, J.D.; Logan, B.G. & Meier, W.R.
Partner: UNT Libraries Government Documents Department

Safety and environmental advantages of using tritium-lean targets for inertial fusion

Description: While traditional inertial fusion energy target designs typically use equimolar portions of deuterium and tritium and have areal densities ({rho}r) of {approx} 3 g/cm{sup 2}, significant safety and environmental (S and E) advantages may be obtained through the use of high-density ({rho}r {approx} 10 g/cm{sup 2}) targets with tritium components as low as 0.5%. Such targets would absorb much of the neutron energy within the target and could be self-sufficient from a tritium breeding point of view. Tritium self-sufficiency within the target would free target chamber designers from the need to use lithium-bearing blanket materials, while low inventories within each target would translate into low inventories in target fabrication facilities. Absorption of much of the neutron energy within the target, the extremely low tritium inventories, and the greatly moderated neutron spectrum, make ''tritium-lean'' targets appear quite attractive from an S and E perspective.
Date: August 9, 1999
Creator: Arzeni, S; Latkowski, J F; Logan, B G; Meier, W R; Moir, R W; Perkins, L J et al.
Partner: UNT Libraries Government Documents Department

Beam Interaction Measurements with a Retarding Field Analyzer in a High-Current High-Vacuum Positively-Charged Particle Accelerator

Description: A Retarding Field Analyzer (RFA) was inserted in a drift region of a magnetic transport section of the high-current experiment (HCX) that is at high-vacuum to measure ions and electrons resulting from beam interaction with background gas and walls. The ions are expelled during the beam by the space-charge potential and the electrons are expelled mainly at the end of the beam, when the beam potential decays. The ion energy distribution shows the beam potential of {approx} 2100 V and the beam-background gas total cross-section of 1.6x10{sup -20} m{sup 2}. The electron energy distribution reveals that the expelled electrons are mainly desorbed from the walls and gain {approx} 22 eV from the beam potential decaying with time before entering the RFA. Details of the RFA design and of the measured energy distributions are presented and discussed.
Date: July 11, 2006
Creator: Covo, M. K.; Molvik, A. W.; Friedman, A.; Barnard, J. J.; Seidl, P. A.; Logan, B. G. et al.
Partner: UNT Libraries Government Documents Department

US Heavy Ion Beam Research for High Energy Density Physics Applications and Fusion

Description: Key scientific results from recent experiments, modeling tools, and heavy ion accelerator research are summarized that explore ways to investigate the properties of high energy density matter in heavy-ion-driven targets, in particular, strongly-coupled plasmas at 0.01 to 0.1 times solid density for studies of warm dense matter, which is a frontier area in high energy density physics. Pursuit of these near-term objectives has resulted in many innovations that will ultimately benefit heavy ion inertial fusion energy. These include: neutralized ion beam compression and focusing, which hold the promise of greatly improving the stage between the accelerator and the target chamber in a fusion power plant; and the Pulse Line Ion Accelerator (PLIA), which may lead to compact, low-cost modular linac drivers.
Date: September 19, 2005
Creator: Davidson, R.C.; Logan, B.G.; Barnard, J.J.; Bieniosek, F.M.; Briggs, R.J. & al., et
Partner: UNT Libraries Government Documents Department

Absolute Measurement of Electron Cloud Density in a Positively-Charged Particle Beam

Description: Clouds of stray electrons are ubiquitous in particle accelerators and frequently limit the performance of storage rings. Earlier measurements of electron energy distribution and flux to the walls provided only a relative electron cloud density. We have measured electron accumulation using ions expelled by the beam. The ion energy distribution maps the depressed beam potential and gives the dynamic cloud density. Clearing electrode current reveals the static background cloud density, allowing the first absolute measurement of the time-dependent electron cloud density during the beam pulse.
Date: May 18, 2006
Creator: Covo, M K; Molvik, A W; Friedman, A; Vay, J; Seidl, P A; Logan, B G et al.
Partner: UNT Libraries Government Documents Department

Beam interaction measurements with a Retarding Field Analyzer

Description: A Retarding Field Analyzer (RFA) was designed and inserted in a drift region of a magnetic transport section of the High Current Experiment (HCX). It measures ions or electrons resulting from the beam interaction with the background gas and walls. The ions are expelled during the beam by the space-charge beam potential, and the electrons are expelled mainly at the end of the beam, when the beam potential decays. The measured electrons have a Maxwellian energy distribution and the measured ions have an energy distribution that gives the information of the beam profile, details will be presented and discussed.
Date: March 28, 2006
Creator: Covo, M K; Molvik, A W; Friedman, A; Barnard, J J; Seidl, P; Logan, B G et al.
Partner: UNT Libraries Government Documents Department

Long Plasma Source for Heavy Ion Beam Charge Neutralization

Description: Plasmas are a source of unbound electrons for charge neutralizing intense heavy ion beams to focus them to a small spot size and compress their axial length. The plasma source should operate at low neutral pressures and without strong externally-applied fields. To produce long plasma columns, sources based upon ferroelectric ceramics with large dielectric coefficients have been developed. The source utilizes the ferroelectric ceramic BaTiO{sub 3} to form metal plasma. The drift tube inner surface of the Neutralized Drift Compression Experiment (NDCX) is covered with ceramic material. High voltage ({approx} 8 kV) is applied between the drift tube and the front surface of the ceramics. A BaTiO{sub 3} source comprised of five 20-cm-long sources has been tested and characterized, producing relatively uniform plasma in the 5 x 10{sup 10} cm{sup -3} density range. The source was integrated into the NDCX device for charge neutralization and beam compression experiments, and yielded current compression ratios {approx} 120. Present research is developing multi-meter-long and higher density sources to support beam compression experiments for high energy density physics applications.
Date: June 1, 2008
Creator: Efthimion, P.C.; Gilson, E.P.; Grisham, L.; Davidson, R.C.; Logan, B.G.; Seidl, P.A. et al.
Partner: UNT Libraries Government Documents Department

Heavy Ion Inertial Fusion Energy: Summaries of Program Elements

Description: The goal of the Heavy Ion Fusion (HIF) Program is to apply high-current accelerator technology to IFE power production. Ion beams of mass {approx}100 amu and kinetic energy {>=} 1 GeV provide efficient energy coupling into matter, and HIF enjoys R&D-supported favorable attributes of: (1) the driver, projected to be robust and efficient; see 'Heavy Ion Accelerator Drivers.'; (2) the targets, which span a continuum from full direct to full indirect drive (and perhaps fast ignition), and have metal exteriors that enable injection at {approx}10 Hz; see 'IFE Target Designs'; (3) the near-classical ion energy deposition in the targets; see 'Beam-Plasma Interactions'; (4) the magnetic final lens, robust against damage; see 'Final Optics-Heavy Ion Beams'; and (5) the fusion chamber, which may use neutronically-thick liquids; see 'Liquid-Wall Chambers.' Most studies of HIF power plants have assumed indirect drive and thick liquid wall protection, but other options are possible.
Date: February 28, 2011
Creator: Friedman, A; Barnard, J J; Kaganovich, I; Seidl, P A; Briggs, R J; Faltens, A et al.
Partner: UNT Libraries Government Documents Department