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Fusion research: the past is prologue

Description: At this juncture fusion research can be viewed as being at a turning point, a time to review its past and to imagine its future. Today, almost 50 years since the first serious attempts to address the daunting problem of achieving controlled fusion, we have both an opportunity and a challenge. Some predictions place fusion research today at a point midway between its first inception and its eventual maturation - in the middle of the 21st century - when fusion would become a major source of energy. Our opportunity therefore is to assess what we have learned from 50 years of hard work and use that knowledge as a starting point for new and better approaches to solving the fusion problem. Our challenge is to prove the "50 more years" prophesy wrong, by finding ways to shorten the time when fusion power becomes a reality. The thesis will be advanced that in the magnetic confinement approach to fusion open-ended magnetic confinement geometries offer much in responding to the challenge. A major advantage of open systems is that, owing to their theoretically and experimentally demonstrated ability to suppress plasma instabilities of both the MHD and the high-frequency wave-particle variety, the confinement becomes predictable from "classical," i.e., Fokker-Planck-type analysis. In a time of straitened budgetary circumstances for magnetic fusion research now being faced in the United States, the theoretical tractability of mirror-based systems is a substantial asset. In pursuing this avenue it is also necessary to keep an open mind as to the forms that mirror-based fusion power plants might take. For example, one can look to the high-energy physics community for a possible model: This community has shown the feasibility of constructing large and complex particle accelerators using superconducting magnets, vacuum chambers and complicated particle-handling technology, housed in underground tunnels that ...
Date: October 14, 1998
Creator: Post, R F
Partner: UNT Libraries Government Documents Department

Open-ended magnetic confinement systems for fusion

Description: Magnetic confinement systems that use externally generated magnetic fields can be divided topologically into two classes: ``closed`` and `open``. The tokamak, the stellarator, and the reversed-field-pinch approaches are representatives of the first category, while mirror-based systems and their variants are of the second category. While the recent thrust of magnetic fusion research, with its emphasis on the tokamak, has been concentrated on closed geometry, there are significant reasons for the continued pursuit of research into open-ended systems. The paper discusses these reasons, reviews the history and the present status of open-ended systems, and suggests some future directions for the research.
Date: May 1, 1995
Creator: Post, R.F. & Ryutov, D.D.
Partner: UNT Libraries Government Documents Department

Vacuum vessel for the tandem Mirror Fusion Test Facility

Description: In 1980, the US Department of Energy gave the Lawrence Livermore National Laboratory approval to design and build a tandem Mirror Fusion Test Facility (MFTF-B) to support the goals of the National Mirror Program. We designed the MFTF-B vacuum vessel both to maintain the required ultrahigh vacuum environment and to structurally support the 42 superconducting magnets plus auxiliary internal and external equipment. During our design work, we made extensive use of both simple and complex computer models to arrive at a cost-effective final configuration. As part of this work, we conducted a unique dynamic analysis to study the interaction of the 32,000-tonne concrete-shielding vault with the 2850-tonne vacuum vessel system. To maintain a vacuum of 2 x 10/sup -8/ torr during the physics experiments inside the vessel, we designed a vacuum pumping system of enormous capacity. The vacuum vessel (4200-m/sup 3/ internal volume) has been fabricated and erected, and acceptance tests have been completed at the Livermore site. The rest of the machine has been assembled, and individual systems have been successfully checked. On October 1, 1985, we began a series of integrated engineering tests to verify the operation of all components as a complete system.
Date: March 10, 1986
Creator: Gerich, J.W.
Partner: UNT Libraries Government Documents Department

Mechanical considerations for MFTF-B plasma-diagnostic system

Description: The reconfiguration of MFTF to a tandem mirror machine with thermal barriers has caused a significant expansion in the physical scope of plasma diagnostics. From a mechanical perspective, it complicates the plasma access, system interfaces, growth and environmental considerations. Conceptual designs characterize the general scope of the design and fabrication which remains to be done.
Date: October 19, 1981
Creator: Thomas, S.R. Jr. & Wells, C.W.
Partner: UNT Libraries Government Documents Department

Integrated operations plan for the MFTF-B Mirror Fusion Test Facility. Volume I. Organization plan

Description: This plan and the accompanying MFTF-B Integrated Operations Plan are submitted in response to UC/LLNL Purchase Order 3883801, dated July 1981. The organization plan also addresses the specific tasks and trade studies directed by the scope of work. The Integrated Operations Plan, which includes a reliability, quality assurance, and safety plan and an integrated logistics plan, comprises the burden of the report. In the first section of this volume, certain underlying assumptions and observations are discussed setting the requirements and limits for organization. Section B presents the recommended structure itself. Section C Device Availability vs Maintenance and Support Efforts and Section D Staffing Levels and Skills provide backup detail and justification. Section E is a trade study on maintenance and support by LLNL staff vs subcontract and Section F is a plan for transitioning from the construction phase into operation. A brief summary of schedules and estimated costs concludes the volume.
Date: December 1, 1981
Partner: UNT Libraries Government Documents Department

Integrated operations plan for the MFTF-B Mirror Fusion Test Facility. Volume II. Integrated operations plan

Description: This document defines an integrated plan for the operation of the Lawrence Livermore National Laboratory (LLNL) Mirror Fusion Test Facility (MFTF-B). The plan fulfills and further delineates LLNL policies and provides for accomplishing the functions required by the program. This plan specifies the management, operations, maintenance, and engineering support responsibilities. It covers phasing into sustained operations as well as the sustained operations themselves. Administrative and Plant Engineering support, which are now being performed satisfactorily, are not part of this plan unless there are unique needs.
Date: December 1, 1981
Partner: UNT Libraries Government Documents Department

Project planning and management techniques of the fast-paced TMX-Upgrade construction

Description: The Tandem Mirror Experiment-Upgrade (TMX-Upgrade) construction will be completed in 18 months at a total cost of $14.5 million. This paper describes the project planning and the management techniques used to complete the TMX-Upgrade within its allocated cost and schedule. In the planning stages of a project, before approval of the proposal, we define major project objectives, create a work breakdown structure (WBS), detail a technical description for each level of the WBS, and provide detailed bottoms-up cost estimates and summary schedules. In the operating phase, which continues throughout the project, we establish budget and schedule baselines. The reporting phase includes The Department of Energy (DOE) reviews of project status at monthly, quarterly, and semiannual intervals. These reports include cost, schedule, manpower, major procurement, and technical status information.
Date: October 26, 1981
Creator: Seberger, C.D. & Chargin, A.K.
Partner: UNT Libraries Government Documents Department

Control and diagnostic data structures for the MFTF

Description: A Data Base Management System (DBMS) is being written as an integral part of the Supervisory Control and Diagnostics System (SCDS) of programs for control of the Mirror Fusion Test Facility (MFTF). The data upon which the DBMS operates consist of control values and evaluative information required for facilities control, along with control values and disgnostic data acquired as a result of each MFTF shot. The user interface to the DBMS essentially consists of two views: a computer program interface called the Program Level Interface (PLI) and a stand-alone interactive program called the Query Level Interface to support terminal-based queries. This paper deals specifically with the data structure capabilities from the viewpoint of the PLI user.
Date: November 12, 1979
Creator: Wade, J.A. & Choy, J.H.
Partner: UNT Libraries Government Documents Department

MFTF exception handling system

Description: In the design of large experimental control systems, a major concern is ensuring that operators are quickly alerted to emergency or other exceptional conditions and that they are provided with sufficient information to respond adequately. This paper describes how the MFTF exception handling system satisfies these requirements. Conceptually exceptions are divided into one of two classes. Those which affect command status by producing an abort or suspend condition and those which fall into a softer notification category of report only or operator acknowledgement requirement. Additionally, an operator may choose to accept an exception condition as operational, or turn off monitoring for sensors determined to be malfunctioning. Control panels and displays used in operator response to exceptions are described.
Date: November 12, 1979
Creator: Nowell, D.M. & Bridgeman, G.D.
Partner: UNT Libraries Government Documents Department

Design lessons from using programmable controllers in the MFTF-B personnel safety and interlocks system

Description: Applying programmable controllers in critical applications such as personnel safety and interlocks systems requires special considerations in the design of both hardware and software. All modern programmable controller systems feature extensive internal diagnostic capabilities to protect against problems such as program memory errors; however most, if not all present designs lack an intrinsic capability for detecting and countering failures on the field-side of their I/O modules. Many of the most common styles of I/O modules can also introduce potentially dangerous sneak circuits, even without component failure. This paper presents the most significant lessons learned to date in the design of the MFTF-B Personnel Safety and Interlocks System, which utilizes two non-redundant programmable controllers with over 800 I/O points each. Specific problems recognized during the design process as well as those discovered during initial testing and operation are discussed along with their specific solutions in hardware and software.
Date: November 29, 1983
Creator: Branum, J.D.
Partner: UNT Libraries Government Documents Department

Recent experimental progress in the TMX-U thermal barrier tandem mirror experiment

Description: Recent experiments on the TMX-U thermal barrier device at LLNL have achieved the end plugging of axial ion losses up to a central cell density of n/sub c/ = 2 x 10/sup 12/ cm. During these tests, the axial potential profile characteristic of a thermal barrier has been measured experimentally, indicating an ion-confining potential greater than 1.5 kV and a potential depression of 0.45 kV in the barrier region. The average beta of hot electrons in the thermal barrier has been increased to 15% and appears limited only by classical scattering and ECRH pulse duration. Furthermore, deuterium ions in the central cell have been heated with ICRF to an average energy of 1.5 keV, with a heating efficiency of 40%. During strong end plugging, the axial ion confinement time reached 50 to 100 ms while the nonambipolar radial ion confinement time was 5 to 15 ms - independent of end plugging. Radial ion confinement time exceeding 100 ms has been attained on shots without end plugging. Plates, floated electrically on the end walls, have increased the radial ion confinement time by a factor of 1.8. Further improvement in the central cell density during end plugging can be expected by increasing the ICRF, improving the central cell vacuum conditions and beam heating efficiency, and increasing the radial extent of the potential control plates on the end walls.
Date: June 22, 1984
Creator: Turner, W.C.; Allen, S.L.; Casper, T.A.; Clauser, J.F.; Coensgen, F.H.; Correll, D.L. et al.
Partner: UNT Libraries Government Documents Department

Thermal barrier confinement experiments in the TMX-U tandem mirror

Description: In our recent experiments on the TMX-U thermal-barrier device, we achieved the end plugging of axial ion losses up to a central cell density of n/sub c/ = 6 x 10/sup 12/ cm/sup -3/. During lower density experiments, we measured the axial potential profile characteristic of a thermal barrier and found an ion-confining potential greater than 1.5 kV and a potential depression of 0.45 kV in the barrier region. The average beta of hot end plug electrons has reached 15% and of hot central cell ions has reached 6%. In addition, we heated deuterium ions in the central cell with ICRF to an average perpendicular energy of 2 keV. During strong end plugging at low density (7 x 10/sup 11/ cm/sup -3/), the axial ion confinement time tau/sub parallel/ reached 50 to 100 ms while the nonambipolar radial ion confinement time tau/sub perpendicular/ was 14 ms - independent of end plugging. Electrically floating end walls increased the radial ion confinement time by a factor of 1.8. At higher densities and lower potentials, tau/sub parallel/ was 6 to 12 ms and tau/sub perpendicular/ exceeded 100 ms.
Date: July 26, 1984
Creator: Simonen, T.C.; Allen, S.L.; Baldwin, D.E.; Casper, T.A.; Clauser, J.F.; Coensgen, F.H. et al.
Partner: UNT Libraries Government Documents Department

Evaluation and recommendations on U. C. Lawrence Livermore Labortory Quality Assurance Program

Description: A study was conducted of the University of California's Lawrence Livermore Laboratory Quality Assurance Program, which focused on training needs and recommendations tailored to the various on-going programs. Specific attention was directed to an assessment of the quality status for the MFTF facility and the capabilities of assigned quality project engineers. Conclusions and recommendations are presented which not only address the purpose of this study, but extend into other areas to provide insight and needs for a total cost effective application of a quality assurance program.
Date: April 12, 1978
Creator: Carpenter, F.D. & Horner, M.H.
Partner: UNT Libraries Government Documents Department

Coupled transport and heating in EBT and EBS

Description: In ELMO Bumpy Torus (EBT) and EBT-like devices, hot electron rings form at the edge of the warm core plasma. As early as 1975 it was recognized that microwave heating, which plays such a significant role in electron dynamics, should be incorporated into transport models. Recent theoretical microwave heating and transport studies suggest that this is critical for explaining EBT experiments. In particular, descriptions of the electron distribution as a sum of only two distributions (i.e., one for the core and one for the rings) are inadequate to understand either the heating or the losses in any depth. Here we discuss the interplay of heating and transport from a kinetic standpoint and point out phenomena associated with the microwave heating at the fundamental and second harmonic of the electron cyclotron frequency. We also compare and contrast these phenomena for the EBT magnetic configuration to those for a variant of the standard EBT - the ELMO Bumpy Square (EBS).
Date: January 1, 1984
Creator: Hedrick, C.L.; Batchelor, D.B.; Chen, G.L.; Goldfinger, R.C.; Hastings, D.E.; Jaeger, E.F. et al.
Partner: UNT Libraries Government Documents Department

Tandem mirror theory workshop

Description: The workshop was divided into three sections which were constituted according to subject matter: RF Heating, MHD Equilibrium and Stability, and Transport and Microstability. An overview from Livermore's point of view was given at the beginning of each session. Each session was assigned a secretary to take notes. These notes have been used in preparing this report on the workshop. The report includes the activities, conclusions, and recommendations of the workshop.
Date: May 1, 1981
Partner: UNT Libraries Government Documents Department

TMX-U (Tandem Mirror Experiment-Upgrade) tandem-mirror thermal-barrier experiments

Description: Thermal-barrier experiments have been carried out in the Tandem Mirror Experiment-Upgrade (TMX-U). Measurements of nonambipolar and ambipolar radial transport show that these transport processes, as well as end losses, can be controlled at modest densities and durations. Central-cell heating methods using ion-cyclotron heating (ICH) and neutral-beam injection have been demonstrated. Potential mesurements with recently developed methods indicate that deep thermal barriers can be established.
Date: October 29, 1986
Creator: Simonen, T.C.; Allen, S.L.; Baldwin, D.E.; Barter, J.D.; Berzins, L.V.; Carter, M.R. et al.
Partner: UNT Libraries Government Documents Department

Perpendicular electron cyclotron emission from hot electrons in TMX-U

Description: Perpendicular electron cyclotron emission (PECE) from the electron cyclotron resonant heating of hot electrons in TMX-U is measured at 30 to 40 and 50 to 75 GHz. This emission is optically thin and is measured at the midplane, f/sub ce/ approx. = 14 GHz, in either end cell. In the west end cell, the emission can be measured at different axial positions thus yielding the temporal history of the hot electron axial profile. These profiles are in excellent agreement with the axial diamagnetic signals. In addition, the PECE signal level correlates well with the diamagnetic signal over a wide range of hot electron densities. Preliminary results from theoretical modeling and comparisons with other diagnostics are also presented.
Date: September 14, 1984
Creator: James, R.A.; Ellis, R.F.; Lasnier, C.J.; Casper, T.A. & Celata, C.M.
Partner: UNT Libraries Government Documents Department

Seismic analysis of the mirror fusion test facility shielding vault

Description: This report presents a seismic analysis of the vault in Building 431 at Lawrence Livermore National Laboratory which houses the mirror Fusion Test Facility. The shielding vault structure is approximately 120 ft long by 80 ft wide and is constructed of concrete blocks approximately 7 x 7 x 7 ft. The north and south walls are approximately 53 ft high and the east wall is approximately 29 ft high. These walls are supported on a monolithic concrete foundation that surrounds a 21-ft deep open pit. Since the 53-ft walls appeared to present the greatest seismic problem they were the first investigated.
Date: April 1, 1981
Creator: Gabrielsen, B.L. & Tsai, K.
Partner: UNT Libraries Government Documents Department

Analytical theory of interchange and compressional Alfven instabilities in EBT

Description: The local stability of the EBT plasma is analyzed for the long wavelength perturbations in the frequency regime, ..omega.. approx. less than or equal to ..cap omega../sub i/(..cap omega../sub i/ is ion cyclotron frequency). In addition to the low frequency interchange instability, the plasma can be unstable to the compressional Alfven wave. Contrary to the previously obtained quadratic dispersion relation in ..omega.. for the interchange mode, our dispersion relations for both types of instabilities are cubic in ..omega... New stability boundaries are found, for the hot electron interchange mode, to relate to the enhanced compressibility of the core plasma in the presence of hot electrons. The compressional Alfven instability is driven due to the coupling of hot electron magnetic drifts and diamagnetic drift with the compressional Alfven wave. The stability conditions of these two types of instabilities are opposite to each other.
Date: July 1, 1981
Creator: Cheng, C.Z. & Tsang, K.T.
Partner: UNT Libraries Government Documents Department