C<Subscript>60</Subscript>-Fullerene Hyper-Velocity High-Density Plasma Jets for MIF and Disruption Mitigation

We present an innovative idea to use hyper-velocity (>30 km/s) high-density (>10¹⁷ cm⁻³) plasma jets of D-T/H and C₆₀-fullerene for magneto-inertial fusion (MIF), high energy density laboratory plasma (HEDLP), and disruption mitigation in magnetic fusion plasma devices. The mass (~1–2 g) of sublimated C₆₀ and hydrogen (or D-T fuel) produced in a pulsed power source is ionized and accelerated as a plasma slug in a coaxial plasma accelerator. For MIF/HEDLP we propose to create a magnetized plasma target by injecting two high-Mach number high-density jets with fuel (D-T) and liner (C₆₀/C) structure along the axis of a pulsed magnetic mirror. The magnetized target fusion (MTF) plasma created by head-on collision and stagnation of jets is compressed radially by a metallic liner (Z-pinch) and axially by the C₆₀/C liner. For disruption mitigation, the C₆₀ plasma jets were shown to be able to provide the required impurity mass (J Fusion Energy 27:6, 2008).     

Review of the magnetic fusion program by the 1986 ERAB Fusion Panel

The 1986 ERAB Fusion Panel finds that fusion energy continues to be an attractive energy source with great potential for the future, and that the magnetic fusion program continues to make substantial technical progress. In addition, fusion research advances plasma physics, a sophisticated and useful branch of applied science, as well as technologies important to industry and defense. These factors fully justify the substantial expenditures by the Department of Energy in fusion research and development (R&D). The Panel endorses the overall program direction, strategy, and plans, and recognizes the importance and timeliness of proceeding with a burning plasma experiment, such as the proposed Compact Ignition Tokamak (CIT) experiment.Presented to the Magnetic Fusion Advisory Committee (La Jolla, California, December 4, 1986)     

The Report of the Subpanel to FESAC Concerning Alternative Concepts

This is the July 1996 report of a subpanel of the US Department of Energy Fusion Energy Sciences Advisory Committee (FESAC), charged with reviewing the present status of fusion alternative concept development and the prospects for alternative concepts not only as fusion power systems but also the scientific contributions of alternative concept research to the fusion energy sciences program and to plasma science in general.     

Effects of Sputtering of and Radiation by Aluminum on Magnetized Target Fusion Plasmas

We estimate numerically the rate of radiation by aluminum impurities for parameters relevant to magnetized target fusion (MTF) plasmas. We demonstrate that the coronal equilibrium is appropriate for expected MTF plasma parameters. Using the coronal equilibrium, we estimate the power radiated per impurity ion is 0.25–0.5 × 10⁻¹⁶ MW for temperatures and densities relevant to present plasma parameters taken from the FRX-L experiment at Los Alamos National Laboratory and is approximately 75.0 × 10⁻¹⁶ MW for temperatures and densities relevant to anticipated MTF plasmas. We calculate the sputtering rate of aluminum by thermal deuterium and tritium plasma ions is a few percent assuming an impact angle of 45°. Finally, we estimate that with aluminum impurity levels of a few percent, the impurity radiation power density would be approximately 25 kW/cm³ for FRX-L conditions and 2.5 GW/cm³ for anticipated conditions in a MTF plasma. While we have assumed a sputtering model of impurity generation, the results for the power density apply for impurity levels of a few percent, regardless of the generation mechanism.     

Spherical Torus Pathway to Fusion Power

Spherical Torus (ST) as an example of confinement concept innovation to enable a potentially attractive pathway to fusion power is discussed. Given the anticipated high performance in small size, the ST plasma could be used to stimulate innovation also in engineering, technology, and material combinations to provide a smarter, cheaper, faster pathway. This pathway could complement the mainline program based on the tokamak in making the desired progress in fusion energy sciences. The ST pathway could include a small VNS (Volume Neutron Source) with low fusion amplification (Q 1–2) for Fusion Energy Development (energy technology) and a small Pilot Plant with high Q (15–30) to practice Fusion Power Demonstration. Success in these steps also enhances the possibility for competitive non-electric applications of interest to society in time scales shorter than electric power generation. The scientific basis for these possibilities will be tested in the U.S. by the Proof of Principle experiment NSTX (National Spherical Torus Experiment) presently being built, and could be completed by a Proof of Performance and Optimization experiment such as a small DTST (Deuterium-Tritium Spherical Torus). Utilization of facilities and equipment already available in the U.S. would minimize the time and cost for these experiments and accelerate the approach to the stage of Fusion Energy Development.     

Development of Merged Compact Toroids for Use as a Magnetized Target Fusion Plasma

We report on the development of compact toroid (CT) accelerators to create the target plasma for magnetized target fusion (MTF) devices. Due to the requirements of high initial density of ~10¹⁷ cm⁻³, strong internal fields of 5–10 T, and base temperatures of >100 eV, a design based on conical compression electrodes is an effective avenue to pursue. Progress is being made at General Fusion Inc, (Vancouver, Canada) to develop a pair of large CT accelerators for generating an MTF target plasma. In this design, tungsten coated conical electrodes (with a formation diameter of 1.9 m, a radial compression factor of 4, and overall accelerator length of 5 m) will be used to achieve ohmic heating and acceleration of the CT, yet with low wall sputtering rates. A pair of these accelerators can be synchronized and shot at one another, producing a collision and reconnection of the two CTs within the center of an MTF chamber. Depending on the choice of relative helicities, the two CTs will merge to form either a spheromak-like or an FRC-like plasma. ICC 2008 Reno NV, June 25th, IP: 021.     

Report of the FESAC Panel on a Burning Plasma Program Strategy to Advance Fusion Energy

This panel was set up by the U.S. Department of Energy's Fusion Energy Sciences Advisory Committee in response to a request from the department to prepare a strategy for the study of burning fusion plasmas. Experimental study of a burning plasma has long been a goal of the U.S. science-based fusion energy program. There is an overwhelming consensus among fusion scientists that we are now ready scientifically, and have the full technical capability, to embark on this step. The fusion community is prepared to construct a facility that will allow us to produce this new plasma state in the laboratory, uncover the new physics associated with the fusion burn, and develop and test new technology essential for fusion power. Given this background, the panel has produced a strategy to enable the United States to proceed with this crucial next step in fusion energy science. The strategy was constructed with awareness that the burning plasma program is only one major component in a comprehensive development plan for fusion energy. A strong core science and technology program focused on fundamental understanding, confinement configuration optimization, and the development of plasma and fusion technologies essential to the realization of fusion energy. The core program will also be essential to the successful guidance and exploitation of the burning plasma program, providing the necessary knowledge base and scientific workforce.     

Cost Effective Steps to Fusion Power: IFE Target Fabrication, Injection and Tracking

This paper was prepared for the Fusion Power Associates workshop on Cost Effective Steps to Fusion Power, 25–27 January 1999, and summarizes the role of IFE target fabrication, injection and tracking must play in pursuing a cost effective development program for inertial fusion energy that will lead to a cost effective fusion power plant.     

Report of the U.S. Department of Energy Fusion Energy Sciences Advisory Committee (FESAC) Panel Reviewing the Theory and Computing Program

This Panel was set up by the Fusion Energy Sciences Advisory Committee (FESAC) at its November 2000 meeting for the purpose of addressing questions from the Department of Energy concerning the theory and computing/simulation program of the Office of Fusion Energy Sciences. Although the Panel primarily addressed programmatic questions, it acknowledges that the theory and computing in fusion energy sciences has a stellar record of research successes. (A recent FESAC report entitled Opportunities in the Fusion Energy Sciences Program listed a number of theory and computing research highlights.) Last year the National Research Council performed an assessment of the quality of the fusion energy sciences program—including theory and computing—and concluded that the quality of its research is on a par with that of other leading areas of contemporary physical science.     

Reaction balance and efficiency analysis of a D-D fusion/fission hybrid with satellite D-3He reactors

Selected reactor physics and isotope balance characteristics of a fusion hybrid supported D-³He satellite nuclear energy system are formulated and investigated. The system consists of two types of reactors: a parent D-fueled fusion device and a number of smaller reactors optimized for D-³He fusion. The parent hybrid station breeds the helium-3 for the satellites and also breeds fissile fuel for an existing fission reactor economy. Various hybrid operational regimes are examined in order to determine favorable reactorQ values and effective fusion and fission efficiencies. A number of analytical correlations between power output, plasma energetics, blanket neutronics, breeding capacity, and energy conversion cycles are established and evaluated. Numerical examples of performance parameters such as fission-to-fusion power, overall conversion efficiency, and the ratio of satellite to parent fusion power are presented. The range of reactor efficiencies is elucidated as affected by the internal plasma power balances. As an upper bound based on optimistic injection and direct conversion efficiencies, we find the D-³He satellite system power output attaining at best 1/3 of the parent fusion power.     

Study on (n,t) Reactions of Zr, Nb and Ta Nuclei

The world faces serious energy shortages in the near future. To meet the world energy demand, the nuclear fusion with safety, environmentally acceptability and economic is the best suited. Fusion is attractive as an energy source because of the virtually inexhaustible supply of fuel, the promise of minimal adverse environmental impact, and its inherent safety. Fusion will not produce CO₂ or SO₂ and thus will not contribute to global warming or acid rain. Furthermore, there are not radioactive nuclear waste problems in the fusion reactors. Although there have been significant research and development studies on the inertial and magnetic fusion reactor technology, there is still a long way to go to penetrate commercial fusion reactors to the energy market. Because, tritium self-sufficiency must be maintained for a commercial power plant. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. And also, the success of fusion power system is dependent on performance of the first wall, blanket or divertor systems. So, the performance of structural materials for fusion power systems, understanding nuclear properties systematic and working out of (n,t) reaction cross sections are very important. Zirconium (Zr), Niobium (Nb) and Tantal (Ta) containing alloys are important structural materials for fusion reactors, accelerator-driven systems, and many other fields. In this study, (n,t) reactions for some structural fusion materials such as ^{88,90,92,94,96}Zr, ^93,94,95Nb and ^179,181Ta have been investigated. The calculated results are discussed andcompared with the experimental data taken from the literature.     

Numerical Modeling of a Magnetic Flux Compression Experiment

A possible plasma target for Magnetized Target Fusion (MTF) is a stable diffuse z-pinch in a toroidal cavity, like that in MAGO experiments. To examine key phenomena of such MTF systems, a magnetic flux compression experiment with this geometry is under design. The experiment is modeled with 3 codes: a slug model, the 1D Lagrangian RAVEN code, and the 1D or 2D Eulerian Magneto-Hydro-Radiative-Dynamics-Research (MHRDR) MHD simulation. Even without injection of plasma, high-Z wall plasma is generated by eddy-current Ohmic heating from MG fields. A significant fraction of the available liner kinetic energy goes into Ohmic heating and compression of liner and central-core material. Despite these losses, efficiency of liner compression, expressed as compressed magnetic energy relative to liner kinetic energy, can be close to 50%. With initial fluctuations (1%) imposed on the liner and central conductor density, 2D modeling manifests liner intrusions, caused by the m = 0 Rayleigh-Taylor instability during liner deceleration, and central conductor distortions, caused by the m = 0 curvature-driven MHD instability. At many locations, these modes reduce the gap between the liner and the central core by about a factor of two, to of order 1 mm, at the time of peak magnetic field.     

Innovative Fusion Tokamak Powerplant and the Basic Engineering for Mhd Theory

All around the world an endeavour to develop the fusion process as a major alternative energy has been going on for about a half century. Aries-St is the spherical tokamak (St) a innovative fusion reactor engineering. This toroidal reactor is a type of system that facilitates the occurrence of the nuclear fusion and fission events together (Tillack et al. in Fusion Energ Des 65:215–261, 2003; El-Guebaly in Fusion Energ Des 65:263–284, 2003). The Aries-St power core consist of the components directly surrounding the burning plasma and serves important functions. In fusion applications, liquid metals are traditionally considered to be the best working fluids. Sufficient tritium breed amount must be TBR >1.1 for Aries-St fusion tokamak power plant (Tillack et al. in Fusion Energ Des 65:215–261, 2003; El-Guebaly in Fusion Energ Des 65:263–284, 2003). The Aries-St power core has designed for correlation with an optimized St plasma that develop through the investigation of extensive range of plasma magnetohydrodynamic (Mhd) equations. In this study, the engineering design plasma parameters are described with respect to Mhd equilibrium and nuclear analysis, stability, radiation heat transfer conditions, current drive, and safety. In addition, turbulence model extended to an incompressible Mhd flows and monte carlo simulation are used for modeling of low-conductivity fluid. In this study the modeling of aries-st tokamak reactor produced by using aries design technology, has performed by using the monte carlo code and Endf/b-V-VI nuclear data. Monte carlo method is the general name for the solution of experimental and statistical problems with a random approach.     

Enabling Technology in Support of Fusion Science

This paper summarizes remarks made at Fusion Power Associates annual meeting, July 17, 2000 in San Diego. It describes the U.S. Department of Energy Office of Fusion Enegy Sciences programs in plasma and fusion technology in support of the U. S. fusion energy sciences program.     

The three RF additional heating systems for FAST

FAST (Fusion Advanced Studies Torus) is a new tokamak machine proposed by the Italian Fusion Association as a Satellite Tokamak for the ITER programme. FAST will operate with deuterium plasmas to avoid the complexity deriving from the use of tritium. Therefore burning plasma conditions, where energy density of fast ions and of charged fusion products is a significant fraction of the total plasma energy density, will be achieved by accelerating plasma ions above the half-MeV range through an Ion Cyclotron Resonance Heating (ICRH) system (P = 30 MW, f = 60–90 MHz). For long pulse Advanced Tokamak (AT) scenarios, a Lower Hybrid Current Drive (LHCD) system (P = 6 MW, f = 3.7 GHz) has been envisaged to actively control the current profile, whereas an Electron Cyclotron Resonant Heating (ECRH) system (P = 4 MW, f = 170 GHz) will provide enough RF power for MHD control.     

2002 Fusion Summer Study Executive Summary

The 2002 Fusion Summer Study was conducted July 8–19, 2002, in Snowmass, CO, and carried out a critical assessment of major next steps in the fusion energy sciences program in both magnetic fusion energy (MFE) and inertial fusion energy (IFE). The conclusions of this study were based on analysis led by over 60 conveners working with hundreds of members of the fusion energy sciences community extending over eight months. This effort culminated in two weeks of intense discussion by over 250 U.S. and 30 foreign fusion physicists and engineers present at the 2002 Fusion Summer Study. This is the Executive Summary of the study report. Details are posted at http://web.gat.com/snowmass     

Commercial objectives,technology transfer,and systems analysis for fusion power development

Fusion is an essentially inexhaustible source of energy that has the potential for economically attractive commercial applications with excellent safety and environmental characteristics. The primary focus for the fusion-energy development program is the generation of centralstation electricity. Fusion has the potential, however, for many other applications. The fact that a large fraction of the energy released in a DT fusion reaction is carried by high-energy neutrons suggests potentially unique applications. These include breeding of fissile fuels, production of hydrogen and other chemical products, transmutation or burning of various nuclear or chemical wastes, radiation processing of materials, production of radioisotopes, food preservation, medical diagnosis and medical treatment, and space power and space propulsion. In addition, fusion R&D will lead to new products and new markets.Each fusion application must meet certain standards of economic and safety and environmental attractiveness. For this reason, economics on the one hand, and safety and environment and licensing on the other hand, are the two primary criteria for setting long-range commercial fusion objectives. A major function of systems analysis is to evaluate the potential of fusion against these objectives and to help guide the fusion R&D program toward practical applications. The transfer of fusion technology and skills from the national laboratories and universities to industry is the key to achieving the long-range objective of commercial fusion applications.     

A Physics Exploratory Experiment on Plasma Liner Formation

Momentum flux for imploding a target plasma in magnetized target fusion (MTF) may be delivered by an array of plasma guns launching plasma jets that would merge to form an imploding plasma shell (liner). In this paper, we examine what would be a worthwhile experiment to explore the dynamics of merging plasma jets to form a plasma liner as a first step in establishing an experimental database for plasma-jets-driven magnetized target fusion (PJETS-MTF). Using past experience in fusion energy research as a model, we envisage a four-phase program to advance the art of PJETS-MTF to fusion breakeven (Q 1). The experiment (PLX) described in this paper serves as Phase 1 of this four-phase program. The logic underlying the selection of the experimental parameters is presented. The experiment consists of using 12 plasma guns arranged in a circle, launching plasma jets toward the center of a vacuum chamber. The velocity of the plasma jets chosen is 200 km/s, and each jet is to carry a mass of 0.2 mg to 0.4 mg. A candidate plasma accelerator for launching these jets consists of a coaxial plasma gun of the Marshall type.     

Stability of Plasma Configurations During Compression

Magnetized Target Fusion (MTF) efforts are based on calculations showing that the addition of a closed magnetic field relaxes the driver pressure and pulse width requirements for inertial confinement fusion by reducing thermal conductivity. Instabilities that result in convective bulk transport at the Alfven time scale are of particular concern since they are much faster than the implosion time. This paper focuses on the hard-core z-pinch and the field reversed configuration (FRC), two competing geometries presently being explored for MTF. Instabilities during compression may result from a violation of the Kadomstev stability criteria for the former, and increased angular velocity due to angular momentum conservation for the latter. Basic analytic considerations are addressed to provide a baseline for more detailed modeling.     

Two Strategic Decisions Facing Fusion

Two strategic decisions facing the U.S. fusion program are described. The first decision deals with the role and rationale of the tokamak within the U. S. fusion program, and it underlies the debate over our continuing role in the evolving ITER collaboration (mid-1998). The second decision concerns how to include Inertial Fusion Energy (IFE) as a viable part of the national effort to harness fusion energy.