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.     

A programmatic framework for the Tokamak Physics Experiment (TPX)

Significant advances have been made in the confinement of reactor-grade plasmas, so that we are now preparing for experiments at the power breakeven level in the JET and TFTR experiments. In ITER we will extend the performance of tokamaks into the burning plasma regime, develop the technology of fusion reactors, and produce over a gigawatt of fusion power. Besides taking these crucial steps toward the technical feasibility of fusion, we must also take steps to ensure its economic acceptability. The broad requirements for economically attractive tokamak reactors based on physics advancements have been set forth in a number of studies. An advanced physics data base is emerging from a physics program of concept improvement using existing tokamaks around the world. This concept improvements program is emerging as the primary focus of the U.S. domestic tokamak program, and a key element of that program is the proposed Tokamak Physics Experiment (TPX). With TPX we can develop the scientific data base for compact, continuously-operating fusion reactors, using advanced steady-state control techniques to improve plasma performance. We can develop operating techniques needed to ensure the success of ITER and provide first-time experience with several key fusion reactor technologies. This paper explains the relationships of TPX to the current U.S. fusion physics program, to the ITER program, and to the development of an attractive tokamak demonstration plant for this next stage in the fusion program.Abbreviations used TFTR Tokamak Fusion Test Reactor - JET Joint European Torus - ARIES Advanced Reactor Innovations Evaluation Study - SSTR Steady State Tokamak Reactor - PBXM Princeton Beta Experiment-Modified - DIII-D Doublet III—Dee - JT60-U Japanese Tokamak 60-Upgrade     

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)     

Near Term Applications of Plasma Science and Fusion Research: National Laboratory Perspectives

This paper describes some of the near-term practical applications of plasma science from the perspective of National Laboratories involved with fusion research for many years. The first half of the paper presents suggestions for maintaining a healthy national program in this area. The second part of the paper gives specific examples of near-term plasma applications research at our laboratories.     

Why Compact Tori for Fusion?

A compact torus (CT) has a toroidal magnetic and plasma geometry, but is contained within a simply-connected vacuum vessel such as a cylinder. Spheromaks and field-reversed configurations fall into this category. Compact tori are translatable and have a high engineering beta. The primary benefit of CTs for fusion is the absence of toroidal field and Ohmic Heating coils and the many problems brought on by them. Studying fusion-relevant plasma in simply-connected geometries affords the world fusion program both physics and technology opportunities not found in other configurations. This paper outlines the technology and physics opportunities of compact tori, and presents a cost model based on geometry for comparison with less compact configurations.     

Three Game Changing Discoveries: A Simpler Fusion Concept?

This paper encourages exploration of a broad range of magnetic fusion concepts in parallel with mainline tokamak development. Such exploration will certainly lead to increased understanding of fusion science and possibly to an attractive fusion energy concept. As an example, this paper describes three discoveries which greatly increase the attractiveness of the magnetic mirror plasma confinement concept. The mirror concept is thought to have three unattractive characteristics. The magnets are complex, the plasma is plagued with micro-instabilities and the electron temperature would never approach required keV levels. Persistent research on the gas dynamic trap device at the Budker Institute of Nuclear Physics in Russia and elsewhere have overcome these three deficiencies. Stable high energy density plasma can be confined with simple circular magnets, micro-instabilities can be tamed, and electron temperatures reaching a keV have been measured. These three accomplishments provide a basis to reconsider the mirror concept as a neutron source for medical applications, fusion materials development, nuclear fuel production, and fusion energy production.     

Could Advanced Fusion Fuels Be Used with Today's Technology?

Could today's technology suffice for engineering advanced-fuel, magnetic-fusion power plants, thus making fusion development primarily a physics problem? Such a path would almost certainly cost far less than the present D-T development program, which is driven by daunting engineering challenges as well as physics questions. Advanced fusion fuels, in contrast to D-T fuel, produce a smaller fraction of the fusion power as neutrons but have lower fusion reactivity, leading to a trade-off between engineering and physics. This paper examines the critical fusion engineering issues and related technologies with an eye to their application in tokamak and alternate-concept D-³He power plants. These issues include plasma power balance, magnets, surface heat flux, input power, fuel source, radiation damage, radioactive waste disposal, and nuclear proliferation.     

Future directions in inertial fusion research

Conclusions The inertial fusion program has shown great progress over the past year. In the present program plan (for 1987–1991), the program was focused on an early 1990s decision date, as suggested by the National Academy of Sciences report. While the exact nature of the decision was not defined, it was generally considered to be a go/no go with regard to a new major facility to achieve high gain. The program's emphasis during this period was consistent with the priorities enumerated by the NAS (Happer) panel and focused on elucidating the conditions needed to achieve high gain. With the progress in target physics that has been made to date, we believe we are rapidly approaching a point when we will be able to say with confidence that a 5–10-MJ facility will provide high gain. Because we are not quite there yet, we believe we must continue to pursue target physics issues vigorously. But, the IF program also needs to accelerate the pace of driver development because in this past year the inertial fusion program has made large strides in showing the feasibility of a high-gain facility.We now believe with the progress that has been made to date that the question is no longer if inertial fusion can be made to work, but when and for how much.     

Revamping Fusion Research

A fundamental revamping of magnetic plasma fusion research is needed, because the current focus of world fusion research—the ITER-tokamak concept—is virtually certain to be a commercial failure. Towards that end, a number of technological considerations are described, believed important to successful fusion research. Beyond critical attention to plasma physics challenges, there must be a much sharper focus on electric utility acceptance criteria, which strongly reflect the public interest. While the ITER-tokamak experience has provided important understanding of a variety of technology issues, it is expensive and time-consuming. Engineers with commercial-world experience must become involved in future fusion research and must have a major influence on program decision-making and evaluation. Fusion engineers will have to be imaginative while being rooted in an understanding of fission reactor development, nuclear regulation, and electric utility realities, the proper consideration of which will impact fusion program success. Properly developed, fusion power holds great promise as an attractive electric power source for the long-term future.     

The physics of ion beam fusion

A broad review of inertial confinement fusion shows how ion beam driven fusion has a number of important advantages over other fusion concepts such as laser driven fusion. The requirements of the beams for target compression are obtained and a discussion is given of the problems of focussing and transporting such beams. Finally, an outline is given of the major areas of current research in the atomic physics required for this field.     

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.     

Frontiers in Fusion Research

Presentations that were made at a Fusion Power Associates symposium, Frontiers in Fusion Research, are summarized. Discussions include the science frontiers of burning plasma physics, magnetic fusion concepts, inertial fusion concepts, and fusion technology.     

Applications of plasma and fusion research

Plasma and other technologies developed in part by fusion energy research programs are being used in a wide variety of commerical and other applications. Applications include efficient production of advanced semiconductor chips and integrated circuits; deposition of anticorrosion and other types of coating; improvements in materials for a wide variety of applications; new techniques for cleaning up and biological applications; improvements in a wide variety of related technologies, such as isotope separation, microwave sources, cryogenics and superconductivity, and optics; new technologies, such as light sources and digital radar; and contributions to many areas of basis science, such as space physics and supercomputing.     

Smaller & Sooner: Exploiting High Magnetic Fields from New Superconductors for a More Attractive Fusion Energy Development Path

The current fusion energy development path, based on large volume moderate magnetic B field devices is proving to be slow and expensive. A modest development effort in exploiting new superconductor magnet technology development, and accompanying plasma physics research at high-B, could open up a viable and attractive path for fusion energy development. This path would feature smaller volume, fusion capable devices that could be built more quickly than low-to-moderate field designs based on conventional superconductors. Fusion’s worldwide development could be accelerated by using several small, flexible devices rather than relying solely on a single, very large device. These would be used to obtain the acknowledged science and technology knowledge necessary for fusion energy beyond achievement of high gain. Such a scenario would also permit the testing of multiple confinement configurations while distributing technical and scientific risk among smaller devices. Higher field and small size also allows operation away from well-known operational limits for plasma pressure, density and current. The advantages of this path have been long recognized—earlier US plans for burning plasma experiments (compact ignition tokamak, burning plasma experiment, fusion ignition research experiment) featured compact high-field designs, but these were necessarily pulsed due to the use of copper coils. Underpinning this new approach is the recent industrial maturity of high-temperature, high-field superconductor tapes that would offer a truly “game changing” opportunity for magnetic fusion when developed into large-scale coils. The superconductor tape form and higher operating temperatures also open up the possibility of demountable superconducting magnets in a fusion system, providing a modularity that vastly improves simplicity in the construction, maintenance, and upgrade of the coils and the internal nuclear engineering components required for fusion’s development. Our conclusion is that while tradeoffs exist in design choices, for example coil, cost and stress limits versus size, the potential physics and technology advantages of high-field superconductors are attractive and they should be vigorously pursued for magnetic fusion’s development.     

Explicit structure-preserving geometric particle-in-cell algorithm in curvilinear orthogonal coordinate systems and its applications to whole-device 6D kinetic simulations of tokamak physics

Explicit structure-preserving geometric particle-in-cell(PIC) algorithm in curvilinear orthogonal coordinate systems is developed. The work reported represents a further development of the structure-preserving geometric PIC algorithm achieving the goal of practical applications in magnetic fusion research. The algorithm is constructed by discretizing the field theory for the system of charged particles and electromagnetic field using Whitney forms, discrete exterior calculus, and explicit non-canonical symplectic integration. In addition to the truncated infinitely dimensional symplectic structure, the algorithm preserves exactly many important physical symmetries and conservation laws, such as local energy conservation, gauge symmetry and the corresponding local charge conservation. As a result, the algorithm possesses the long-term accuracy and fidelity required for first-principles-based simulations of the multiscale tokamak physics. The algorithm has been implemented in the Sym PIC code, which is designed for highefficiency massively-parallel PIC simulations in modern clusters. The code has been applied to carry out whole-device 6 D kinetic simulation studies of tokamak physics. A self-consistent kinetic steady state for fusion plasma in the tokamak geometry is numerically found with a predominately diagonal and anisotropic pressure tensor. The state also admits a steady-state subsonic ion flow in the range of 10 km s~(-1), agreeing with experimental observations and analytical calculations Kinetic ballooning instability in the self-consistent kinetic steady state is simulated.It is shown that high-n ballooning modes have larger growth rates than low-n global modes, and in the nonlinear phase the modes saturate approximately in 5 ion transit times at the 2% level by the E × B flow generated by the instability. These results are consistent with early and recent electromagnetic gyrokinetic simulations.     

X-rays Production by 15-55 MeV Carbon Ions Striking Metal Surfaces

A-100区奇奇核存在着丰富的核结构信息，例如形状共存、三轴形变、带终结以及磁转动带与手征二重带等。在前人的实验结果中，^112In的高自旋态信息很少，仅观测到10ˉh。本次实验的目的是为进一步研究^112In的高自旋态结构，并且寻找其可能存在的磁转动带与手征二重带。     

Summary of US–Japan Exchange 2004: New Directions and Physics for Compact Toroids

Scientists from research institutions in the United States of America and Japan attended a USA Department of Energy sponsored joint international workshop on the subject of Compact Toroids (CT) in Santa Fe, NM, USA in September 2004. We outline here a summary of the topics that were discussed, some of the implications, and new directions that are likely to follow from this research. Experimental, theoretical and computational results were presented. The experimental devices and concepts, along with the theory and computational models comprise investigations of fundamental plasma physics, fusion science, and approaches to fusion energy that require magnetized plasmas.     

The TEXTOR program at the KFA,Jülich

The problem of impurity generation in fusion devices has, as a consequence of rapid development in the confinement sector, reached a high priority level. In collaboration with the KFA institutes for surface and vacuum physics, nuclear chemistry, solid state physics, reactor development, reactor materials, and others, the Institute for Plasma Physics of the KFA has initiated a program for a systematic study of the interaction of hot confined plasmas with the surrounding first wall. Because of the nonlinear character of the problem, not only simulation measurements but also the availability of a tokamaktype flexible confinement device, TEXTOR, with adequate access to all domains of relevance is held indispensible. Essential parameters of TEXTOR are major and minor plasma radii 175 and 50 cm, toroidal field 2 T initially, 2.6 T later, flux swing 4.1 Vs, wall temperature up to 600°C, and easy exchange ability of first wall.     

A Fusion Development Facility Based on the Spherical Torus

The Fusion community could soon have available an opportunity to significantly advance fusion development, an opportunity afforded by the potential of the spherical torus as a plasma confinement system. That opportunity is, in a single device at an affordable price and at a suitable site, to move sequentially through the major fusion objectives of advanced confinement physics, burning plasma and DT physics, blanket and other fusion nuclear technology development, tritium self-sufficiency, and, perhaps at the end with an upside performance outcome, a chance at net electric breakeven. Meeting this set of objectives would dramatically advance the development of fusion.     

Controlling Fusion Yield in Tokamaks with Spin Polarized Fuel,and Feasibility Studies on the DIII-D Tokamak

The march towards electricity production through tokamaks requires the construction of new facilities and the inevitable replacement of the previous generation. There are, however, research topics that are better suited to the existing tokamaks, areas of great potential that are not sufficiently mature for implementation in high power machines, and these provide strong support for a balanced policy that includes the redirection of existing programs. Spin polarized fusion, in which the nuclei of tokamak fuel particles are spin-aligned and favorably change both the fusion cross-section and the distribution of initial velocity vectors of charged fusion products, is described here as an example of a technological and physics topic that is ripe for development in a machine such as the DIII-D tokamak. Such research and development experiments may not be efficient at the ITER-scale, while the plasma performance, diagnostic access, and collaborative personnel available within the United States’ magnetic fusion research program, and at the DIII-D facility in particular, provide a unique opportunity to further fusion progress.