L. John Perkins

Submegajoule liner implosion of a closed field line configuration

The adiabatic compression of a preformed closed field line configuration by an imploding liner is considered. Three configurations are discussed: the field-reversed configuration, the spheromak, and the Z-pinch. It is shown that by employing a two-dimensional compression, one can reach a breakeven condition with an energy input into the plasma as low as 100 kJ. A brief discussion of various phenomena affecting the plasma wall confinement is presented. It is shown that heat losses to the walls are modest and do not limit the plasma enhancement factor Q. The derived scaling law for Q versus the input parameters of the system shows a relatively weak dependence of Q on the input energy. 34 refs., 9 figs., 2 tabs.

Assessment of Potential for Ion-Driven Fast Ignition

Abstract Critical issues and ion beam requirements are explored for fast ignition using ion beams to provide fuel compression using indirect drive and to provide separate short-pulse ignition heating using direct drive. Several ion species with different hohlraum geometries are considered for both accelerator-produced and laser-produced ion ignition beams. Ion-driven fast ignition targets are projected to have modestly higher gains than with conventional heavy ion fusion and may offer some other advantages for target fabrication and for use of advanced fuels. However, much more analysis and additional experiments are needed before conclusions can be drawn regarding the feasibility for meeting the ion beam transverse and longitudinal emittances, focal spots, pulse lengths, and target standoff distances required for ion-driven fast ignition.

Quasispherical fuel compression and fast ignition in a heavy-ion-driven X-target with one-sided illumination

The HYDRA radiation-hydrodynamics code [M. M. Marinak et al., Phys. Plasmas 8, 2275 (2001)] is used to explore one-sided axial target illumination with annular and solid-profile uranium ion beams at 60 GeV to compress and ignite deuterium-tritium fuel filling the volume of metal cases with cross sections in the shape of an “X” (X-target). Quasi-three-dimensional, spherical fuel compression of the fuel toward the X-vertex on axis is obtained by controlling the geometry of the case, the timing, power, and radii of three annuli of ion beams for compression, and the hydroeffects of those beams heating the case as well as the fuel. Scaling projections suggest that this target may be capable of assembling large fuel masses resulting in high fusion yields at modest drive energies. Initial two-dimensional calculations have achieved fuel compression ratios of up to 150X solid density, with an areal density ρR of about 1 g/cm2. At these currently modest fuel densities, fast ignition pulses of 3 MJ, 60 GeV, 50 ps, a...

Design of a deuterium and tritium-ablator shock ignition target for the National Ignition Facility

Shock ignition presents a viable path to ignition and high gain on the National Ignition Facility (NIF). In this paper, we describe the development of the 1D design of 0.5 MJ class, all-deuterium and tritium (fuel and ablator) shock ignition target that should be reasonably robust to Rayleigh-Taylor fluid instabilities, mistiming, and hot electron preheat. The target assumes “day one” NIF hardware and produces a yield of 31 MJ with reasonable allowances for laser backscatter, absorption efficiency, and polar drive power variation. The energetics of polar drive laser absorption require a beam configuration with half of the NIF quads dedicated to launching the ignitor shock, while the remaining quads drive the target compression. Hydrodynamic scaling of the target suggests that gains of 75 and yields 70 MJ may be possible.

An indirect-drive non-cryogenic double-shell path to 1ω Nd-laser hybrid inertial fusion–fission energy

A high-yield, room temperature, double-shell target design using a Nd : glass laser driver at the fundamental frequency 1ω is developed for hybrid inertial fusion–fission energy generation (Moses et al 2009 Fusion Sci. Technol. 56 547). The associated 4–10× fission energy gain relaxes the gain requirements of the fusion driver, enabling the prospect of a volume-ignition target with high thermonuclear burn fraction, simplified (1ω) laser operations from a quasi-impulsive power history, room temperature fielding, minimal shock-timing requirements and reduced risk of plasma-mediated laser backscatter with a vacuum hohlraum.

Optimization of a CNG Series Hybrid Concept Vehicle

Compressed Natural Gas (CNG) has favorable characteristics as a vehicular fuel, in terms of fuel economy as well as emissions. Using CNG as a fuel in a series hybrid vehicle has the potential of resulting in very high fuel economy (between 26 and 30 km/liter, 60 to 70 mpg) and very low emissions (substantially lower than Federal Tier II or CARB ULEV). This paper uses a vehicle evaluation code and an optimizer to find a set of vehicle parameters that result in optimum vehicle fuel economy. The vehicle evaluation code used in this analysis estimates vehicle power performance, including engine efficiency and power, generator efficiency, energy storage device efficiency and state-of-charge, and motor and transmission efficiencies. Eight vehicle parameters are selected as free variables for the optimization. The optimum vehicle must also meet two perfect requirements: accelerate to 97 km/h in less than 10 s, and climb an infinitely long hill with a 6% slope at 97 km/h with a 272 kg (600 lb.) payload. The optimizer used in this work was originally developed in the magnetic fusion energy program, and has been used to optimize complex systems, such as magnetic and inertial fusion devices, neutron sources, and mil guns. The optimizer consists of two parts: an optimization package for minimizing non-linear functions of many variables subject to several non-linear equality and/or inequality constraints and a programmable shell that allows interactive configuration and execution of the optimizer. The results of the analysis indicate that the CNG series hybrid vehicle has a high efficiency and low emissions. These results emphasize the advantages of CNG as a near-term alternative fuel for vehicles.

THE ROLE OF INERTIAL FUSION ENERGY IN THE ENERGY MARKETPLACE OF THE 21ST CENTURY AND BEYOND

Abstract The viability of inertial fusion in the 21st century and beyond will be determined by its ultimate cost, complexity, and development path relative to other competing, long term, primary energy sources. We examine this potential marketplace in terms of projections for population growth, energy demands, competing fuel sources and environmental constraints (CO 2 ), and show that the two competitors for inertial fusion energy (IFE) in the medium and long term are methane gas hydrates and advanced, breeder fission; both have potential fuel reserves that will last for thousands of years. Relative to other classes of fusion concepts, we argue that the single largest advantage of the inertial route is the perception by future customers that the IFE fusion power core could achieve credible capacity factors, a result of its relative simplicity, the decoupling of the driver and reactor chamber, and the potential to employ thick liquid walls. In particular, we show that the size, cost and complexity of the IFE reactor chamber is little different to a fission reactor vessel of the same thermal power. Therefore, relative to fission, because of IFEs tangible advantages in safety, environment, waste disposal, fuel supply and proliferation, our research in advanced targets and innovative drivers can lead to a certain, reduced-size driver at which future utility executives will be indifferent to the choice of an advanced fission plant or an advanced IFE power plant; from this point on, we have a competitive commercial product. Finally, given that the major potential customer for energy in the next century is the present developing world, we put the case for future IFE “reservations” which could be viable propositions providing sufficient reliability and redundancy can be realized for each modular reactor unit.

Fusion, the Competition, and the Prospects for Alternative Fusion Concepts

Although we have achieved great progress in the scientific understanding of fusion, there is some question whether our present, mainline approach to a fusion reactor will lead to a sufficiently attractive commercial product able to compete in the energy market place of the 21st century. This is a result of the projected low power density, high complexity, large unit sizes, and very high development costs. We assess these attributes relative to other future competitive energy sources and offer the thesis that any step change in the reactor product may lie in the exploration of novel, relatively unexplored or revisited physics concepts rather than in refined engineering for the present single approach. We then provide an overview of potential alternative fusion concepts under the following classification system: (1) Low density magnetic confinement, (2) Inertial confinement concepts, (3) High density magnetic confinement schemes, (4) Non-thermonuclear concepts, and (5) Coulomb barrier reduction concepts. To be considered a serious contender, any new candidate fusion scheme must point the way to an engineering realization that is a step- change in reactor attractiveness from our present approach. Specifically, this means we must clearly identify the potential for significantly lower capital costs, complexity, and development costs relative to those projected for the conventional tokamak.

Development of Fusion Power Seen as Essential to World's Energy Future; Critics Respond

This letter notes the progress in plasma physics and device engineering required to make fusion power a viable option for electric power generation in the 21st century. (AIP) {copyright} {ital 1997 American Institute of Physics.}

Mars Axicell Radiation Damage and Shielding Analysis

Radiation effects and shield requirements are analyzed for the MARS axicell region. Dominant coil life limiting effects in the normal insert coils are found to be swelling in the spinel insulation and resistivity changes of the conductor due to transmutations. The shield between the insert and superconducting coils is optimized and reduces all radiation responses to acceptable levels. However, streaming in the neutral beam duct resulted in an unacceptable dpa rate in the Cu stabilizer and has resulted in a redesign of this region without a neutral beam and with a single insert coil.