Application of microdosimetry on biological physics for ionizing radiation

NASA Astrophysics Data System (ADS)

Chen, Dandan; Sun, Liang

2018-02-01

Not Available Project supported by the National Natural Science Foundation of China (Grant Nos. 11304212 and 11575124), the Natural Science Foundation of Jiangsu Province, China (Grant Nos. BK20130279), the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD), and the International Thermonuclear Experimental Reactor (ITER) Special Program of China (Grant No. 2014GB112006).

Critical assembly: A technical history of Los Alamos during the Oppenheimer years, 1943--1945

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoddeson, L.; Henriksen, P.W.; Meade, R.A.

1993-11-01

This volume treats the technical research that led to the first atomic bombs. The authors explore how the ``critical assembly`` of scientists, engineers, and military Personnel at Los Alamos collaborated during World War II, blending their traditions to create a new approach to large-scale research. The research was characterized by strong mission orientation, multidisciplinary teamwork, expansion of the scientists` traditional methodology with engineering techniques, and a trail-and-error methodology responding to wartime deadlines. The book opens with an introduction laying out major themes. After a synopsis of the prehistory of the bomb project, from the discovery of nuclear fission to themore » start of the Manhattan Engineer District, and an overview of the early materials program, the book examines the establishment of the Los Alamos Laboratory, the implosion and gun assembly programs, nuclear physics research, chemistry and metallurgy, explosives, uranium and plutonium development, confirmation of spontaneous fission in pile-produced plutonium, the thermonuclear bomb, critical assemblies, the Trinity test, and delivery of the combat weapons.« less

NASA superconducting magnetic mirror facility. [for thermonuclear research

NASA Technical Reports Server (NTRS)

Reinmann, J. J.; Swanson, M. C.; Nichols, C. R.; Bloy, S. J.; Nagy, L. A.; Brady, F. J.

1973-01-01

The design details and initial test results of a superconducting magnetic mirror facility that has been constructed at NASA Lewis Research Center for use in thermonuclear research are summarized. The magnet system consists of four solenoidal coils which are individually rated at 5.0 T. Each coll is composed of an inner, middle, and outer winding. The inner winding is wound of stabilized Nb3Sn superconducting ribbon, and the middle and outer windings are wound of stabilized Nb-Ti superconducting wire. When arranged in the mirror geometry, the four coils will produce 8.7 T at the mirrors and a 1.8 mirror ratio. The magnet has a 41-cm diameter clear bore which is open to atmosphere. Distance between the mirrors is 111 cm. Presently there are only three magnets in the facility; the fourth magnet is being rebuilt.

The choice of the energy embedding law in the design of heavy ionic fusion cylindrical targets

NASA Astrophysics Data System (ADS)

Dolgoleva, GV; Zykova, A. I.

2017-10-01

The paper considers the numerical design of heavy ion fusion (FIHIF) targets, which is one of the branches of controlled thermonuclear fusion (CTF). One of the important tasks in the targets design for controlled thermonuclear fusion is the energy embedding selection whereby it is possible to obtain “burning” (the presence of thermonuclear reactions) of the working DT region. The work is devoted to the rapid ignition of FIHIF targets by means of an additional short-term energy contribution to the DT substance already compressed by massively more longer by energy embedding. This problem has been fairly well studied for laser targets, but this problem is new for heavy ion fusion targets. Maximum momentum increasing is very technically difficult and expensive on modern FIHIF installations. The work shows that the additional energy embedding (“igniting” impulse) reduces the requirements to the maximum impulse. The purpose of this work is to research the ignition impulse effect on the FIHIF target parameters.

Igniting the Light Elements: The Los Alamos Thermonuclear Weapon Project, 1942-1952

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fitzpatrick, Anne C.

1999-07-01

The American system of nuclear weapons research and development was conceived and developed not as a result of technological determinism, but by a number of individual architects who promoted the growth of this large technologically-based complex. While some of the technological artifacts of this system, such as the fission weapons used in World War II, have been the subject of many historical studies, their technical successors--fusion (or hydrogen) devices--are representative of the largely unstudied highly secret realms of nuclear weapons science and engineering. In the postwar period a small number of Los Alamos Scientific Laboratory's staff and affiliates were responsiblemore » for theoretical work on fusion weapons, yet the program was subject to both the provisions and constraints of the US Atomic Energy Commission, of which Los Alamos was a part. The Commission leadership's struggle to establish a mission for its network of laboratories, least of all to keep them operating, affected Los Alamos's leaders' decisions as to the course of weapons design and development projects. Adapting Thomas P. Hughes's ''large technological systems'' thesis, I focus on the technical, social, political, and human problems that nuclear weapons scientists faced while pursuing the thermonuclear project, demonstrating why the early American thermonuclear bomb project was an immensely complicated scientific and technological undertaking. I concentrate mainly on Los Alamos Scientific Laboratory's Theoretical, or T, Division, and its members' attempts to complete an accurate mathematical treatment of the ''Super''--the most difficult problem in physics in the postwar period--and other fusion weapon theories. Although tackling a theoretical problem, theoreticians had to address technical and engineering issues as well. I demonstrate the relative value and importance of H-bomb research over time in the postwar era to scientific, politician, and military participants in this project. I analyze how and when participants in the H-bomb project recognized both blatant and subtle problems facing the project, how scientists solved them, and the relationship this process had to official nuclear weapons policies. Consequently, I show how the practice of nuclear weapons science in the postwar period became an extremely complex, technologically-based endeavor.« less

Schools and Civil Defense.

ERIC Educational Resources Information Center

Office of Civil Defense (DOD), Washington, DC.

Civil defense is a planned, coordinated action to protect the population during any emergency whether arising from thermonuclear attack or natural disaster. The Federal Government has assumed four responsibilities--(1) to keep track of the nature of the threat which the civil defense program must meet, (2) to prepare and disseminate information…

Energy research: accelerator builders eager to aid fusion work.

PubMed

Metz, W D

1976-10-15

Useful fusion energy may be generated by means of heavy ion accelerator driven implosions if the contraints dictated by the physics and economics of thermonuclear targets and reactors can be satisfied.

Gamma Rays from Classical Novae

NASA Technical Reports Server (NTRS)

1997-01-01

NASA at the University of Chicago, provided support for a program of theoretical research into the nature of the thermonuclear outbursts of the classical novae and their implications for gamma ray astronomy. In particular, problems which have been addressed include the role of convection in the earliest stages of nova runaway, the influence of opacity on the characteristics of novae, and the nucleosynthesis expected to accompany nova outbursts on massive Oxygen-Neon-Magnesium (ONeMg) white dwarfs. In the following report, I will identify several critical projects on which considerable progress has been achieved and provide brief summaries of the results obtained:(1) two dimensional simulation of nova runaway; (2) nucleosynthesis of nova modeling; and (3) a quasi-analytic study of nucleosynthesis in ONeMg novae.

Life of War, Death of the Rest: The Shining Path of Cormac McCarthy's Thermonuclear America

ERIC Educational Resources Information Center

Blackmore, Tim

2009-01-01

The Bush Administration's quiet resumption of, or initiation of new, nuclear weapons programs aimed militarizing space, and erecting a missile defense shield that would have the effect of rolling back 19 years of solid detente, has gone largely unnoticed over the last eight years. Weapons makers, government officials and politicians have expressed…

Research activities in nuclear astrophysics and related areas

NASA Technical Reports Server (NTRS)

1996-01-01

NASA/GRO grant NAG 5-2081, at the University of Chicago, has provided support for a broad program of theoretical research in nuclear astrophysics and related areas, with regard to gamma-ray and hard X-ray emission from classical nova explosions. This research emphasized the possible detection of 22Na gamma-ray line emission from nearby novae involving ONeMg white dwarfs, the detailed examination of 26Al production in novae, and the possible detection of the predicted early gamma ray emission from novae that arises from the decay of the short lived, positron emitting isotopes of CNO elements. Studies of nova related problems have consumed an increasing fraction of the Principal Investigator's research efforts over the past decade. Current research addresses problems associated with the standard model for the outbursts of the classical novae: the occurrence of thermonuclear runaways (TNR) in the accreted hydrogen rich envelopes on white dwarfs in close binary systems (see, e.g., the reviews by Truran 1982; and Shara 1989). Research in progress and planned for the next three years has three main objectives: (1) to gain an improved understanding of the early evolution of the light curves of, particularly, the fastest novae; (2) to gain an improved understanding of the relative importance of the various possible mechanisms of envelope hydrogen depletion (e.g. winds, common envelope driven mass loss, and nuclear burning) to the long term evolution of novae in outburst; and (3) to seek to provide a somewhat more definitive statement of the role of classical novae in nucleosynthesis. Our proposed 2-D studies of convection during the early phases of the TNR and our systematic attempt to incorporate an improved treatment of radiation hydrodynamics into the hydrodynamic code utilized in our calculations, are particularly relevant to the first of these objectives. Further 2-D studies of the effects of common envelope evolution are intended to provide more realistic constraints on the mass depletion mechanisms. Finally, detailed calculations of the thermonuclear history of the matter ejected in novae will be carried out for representative nova configurations involving both carbon-oxygen (CO) and oxygen-neon-magnesium (ONeMg) white dwarfs.

FROM THE HISTORY OF PHYSICS: The extraordinarily beautiful physical principle of thermonuclear charge design (on the occasion of the 50th anniversary of the test of RDS-37 — the first Soviet two-stage thermonuclear charge)

NASA Astrophysics Data System (ADS)

Goncharov, German A.

2005-11-01

On 22 November 1955, the Semipalatinsk test site saw the test of the first domestic two-stage thermonuclear RDS-37 charge. The charge operation was based on the principle of radiation implosion. The kernel of the principle consists in the radiation generated in a primary A-bomb explosion and confined by the radiation-opaque casing propagating throughout the interior casing volume and flowing around the secondary thermonuclear unit. The secondary unit experiences a strong compression under the irradiation, with a resulting nuclear and thermonuclear explosion. The RDS-37 explosion was the strongest of all those ever realized at the Semipalatinsk test site. It produced an indelible impression on the participants in the test. This document-based paper describes the genesis of the ideas underlying the RDS-37 design and reflects the critical moments in its development. The advent of RDS-37 was an outstanding accomplishment of the scientists and engineers of our country.

ORNL `90

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, T.; Barnes, D.; Jefferson, J.

1990-12-31

This overview of research conducted at ORNL in 1991 presents information on the subjects of biology, physics, and the environment. Specific topics include gene mutations in kidney disease, technology assessments in thermonuclear fusion, submarine hunting technology, ozone-safe refrigerants, optical data storage via surface enhanced raman spectroscopy, and waste mitigating microbes. (GHH)

ORNL '90

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, T.; Barnes, D.; Jefferson, J.

1990-01-01

This overview of research conducted at ORNL in 1991 presents information on the subjects of biology, physics, and the environment. Specific topics include gene mutations in kidney disease, technology assessments in thermonuclear fusion, submarine hunting technology, ozone-safe refrigerants, optical data storage via surface enhanced raman spectroscopy, and waste mitigating microbes. (GHH)

Nucleosynthesis in Thermonuclear Supernovae

NASA Astrophysics Data System (ADS)

Seitenzahl, Ivo Rolf; Townsley, Dean M.

The explosion energy of thermonuclear (type Ia) supernovae is derived from the difference in nuclear binding energy liberated in the explosive fusion of light "fuel" nuclei, predominantly carbon and oxygen, into more tightly bound nuclear "ash" dominated by iron and silicon group elements. The very same explosive thermonuclear fusion event is also one of the major processes contributing to the nucleosynthesis of the heavy elements, in particular the iron-group elements. For example, most of the iron and manganese in the sun and its planetary system were produced in thermonuclear supernovae. Here, we review the physics of explosive thermonuclear burning in carbon-oxygen white dwarf material and the methodologies utilized in calculating predicted nucleosynthesis from hydrodynamic explosion models. While the dominant explosion scenario remains unclear, many aspects of the nuclear combustion and nucleosynthesis are common to all models and must occur in some form in order to produce the observed yields. We summarize the predicted nucleosynthetic yields for existing explosion models, placing particular emphasis on characteristic differences in the nucleosynthetic signatures of the different suggested scenarios leading to type Ia supernovae. Following this, we discuss how these signatures compare with observations of several individual supernovae, remnants, and the composition of material in our galaxy and galaxy clusters.

Current status of nuclear engineering education

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palladino, N.J.

1975-09-01

The 65 colleges and universities offering undergraduate degrees in nuclear engineering and the 15 schools offering strong nuclear engineering options are, in general, doing a good job to meet the current spectrum of job opportunities. But, nuclear engineering programs are not producing enough graduates to meet growing demands. They currently receive little aid and support from their customers --industry and government--in the form of scholarships, grants, faculty research support, student thesis and project support, or student summer jobs. There is not enough interaction between industry and universities. Most nuclear engineering programs are geared too closely to the technology of themore » present family of reactors and too little to the future breeder reactors and controlled thermonuclear reactors. In addition, nuclear engineering programs attract too few women and members of minority ethnic groups. Further study of the reasons for this fact is needed so that effective corrective action can be taken. Faculty in nuclear engineering programs should assume greater initiative to provide attractive and objective nuclear energy electives for technical and nontechnical students in other disciplines to improve their technical understanding of the safety and environmental issues involved. More aggressive and persistent efforts must be made by nuclear engineering schools to obtain industry support and involvement in their programs. (auth)« less

Peaceful Uses of Fusion

DOE R&D Accomplishments Database

Teller, E.

1958-07-03

Applications of thermonuclear energy for peaceful and constructive purposes are surveyed. Developments and problems in the release and control of fusion energy are reviewed. It is pointed out that the future of thermonuclear power reactors will depend upon the construction of a machine that produces more electric energy than it consumes. The fuel for thermonuclear reactors is cheap and practically inexhaustible. Thermonuclear reactors produce less dangerous radioactive materials than fission reactors and, when once brought under control, are not as likely to be subject to dangerous excursions. The interaction of the hot plasma with magnetic fields opens the way for the direct production of electricity. It is possible that explosive fusion energy released underground may be harnessed for the production of electricity before the same feat is accomplished in controlled fusion processes. Applications of underground detonations of fission devices in mining and for the enhancement of oil flow in large low-specific-yield formations are also suggested.

Mid-Infrared Signatures from Type Ia Supernovae Strongly Interacting with a Circumstellar Medium

NASA Astrophysics Data System (ADS)

Fox, Ori

2015-10-01

Type Ia supernovae (SNe Ia) are well-known for their use as precise cosmological distance indicators due to a standardizable peak luminosity resulting from a thermonuclear explosion. A growing subset of SNe Ia, however, show evidence for interaction with a dense circumstellar medium during the first year post-explosion, and sometimes longer (SNe Ia-CSM). The origin of this dense CSM is unknown and suggests either a) the less typical single-degenerate progenitor scenario must be considered or b) the exploding star was not a thermonuclear explosion of a white dwarf at all (i.e., core-collapse). Mid-infrared (IR) observations, in particular, are critical for tracing the density profile of dust (and hence gas) in the surrounding CSM. Yet no Spitzer light curve exists for this subclass within the first year post-expolosion. Here we propose a 'low-impact' (>8 weeks) ToO to obtain 3 epochs of Spitzer imaging of a SN Ia-CSM within 100 Mpc over 1 year post-explosion. The strength of this program is that it will be in conjunction with pre-approved multi-wavelength programs on HST/STIS/UV (GO 13649), Chandra/ASIS-S (Num: 17500672), the Keck/LRIS optical spectrograph (Num: U037LA), and the RATIR visible/infrared robotic imager. Requiring only 2.1 hours of observation total, this program will not only distinguish between the SN explosion mechanisms, but also trace CSM interaction, constrain the progenitor mass loss history, and identify late-time heating mechanisms of warm dust.

Laser Fusion - A New Thermonuclear Concept

ERIC Educational Resources Information Center

Cooper, Ralph S.

1975-01-01

Describes thermonuclear processes induced by interaction of a laser beam with the surface of a fuel pellet. An expanding plasma is formed which results in compression of the element. Laser and reactor technology are discussed. Pictures and diagrams are included. (GH)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barnett, C.F.; Gauster, W.B.; Ray, J.A.

A graphical compilation is presented of atomic and molecular cross sections of interest to controlled thermonuclear research. The cross sections are shown, as a function of energy, for collision processes involving molecular ion dissociation, charge exchange, excitation, ionization, photoionization, scattering, energy loss, and recombination. Pertinent nuclear cross sections are also included. A bibliography is given covering the literature since 1950. (auth)

FOREWORD: 23rd National Symposium on Plasma Science & Technology (PLASMA-2008)

NASA Astrophysics Data System (ADS)

Das, A. K.

2010-01-01

The Twentieth Century has been a defining period for Plasma Science and Technology. The state of ionized matter, so named by Irving Langmuir in the early part of twentieth century, has now evolved in to a multidisciplinary area with scientists and engineers from various specializations working together to exploit the unique properties of the plasma medium. There have been great improvements in the basic understanding of plasmas as a many body system bound by complex collective Coulomb interactions of charges, atoms, molecules, free radicals and photons. Simultaneously, many advanced plasma based technologies are increasingly being implemented for industrial and societal use. The emergence of the multination collaborative project International Thermonuclear Experimental Reactor (ITER) project has provided the much needed boost to the researchers working on thermonuclear fusion plasmas. In addition, the other plasma applications like MHD converters, hydrogen generation, advanced materials (synthesis, processing and surface modification), environment (waste beneficiation, air and water pollution management), nanotechnology (synthesis, deposition and etching), light production, heating etc are actively being pursued in governmental and industrial sectors. For India, plasma science and technology has traditionally remained an important area of research. It was nearly a century earlier that the Saha ionization relation pioneered the way to interpret experimental data from a vast range of near equilibrium plasmas. Today, Indian research contributions and technology demonstration capabilities encompass thermonuclear fusion devices, nonlinear plasma phenomena, plasma accelerators, beam plasma interactions, dusty and nonneutral plasmas, industrial plasmas and plasma processing of materials, nano synthesis and structuring, astrophysical and space plasmas etc. India's participation in the ITER programme is now reflected in increased interest in the research and development efforts on Tokamak technology and physics of magnetized fusion plasmas. Our industries have already adopted a large number of plasma processes related to manufacturing, lighting and surface engineering. Indian universities and National Institutes have successfully taken up research projects and building of demonstration equipment that are being used in strategic as well as other industrial applications. In addition, and more importantly, plasma science has triggered research and development effort in many related areas like power supplies, specialized instrumentation and controls, magnets, diagnostics and monitoring, lasers, electron beams, vacuum systems, thermal engineering, material science, fluid dynamics, molecular and nano engineering, molecular chemistry etc. In short, plasma science and technology in India has reached a stage of maturity that can be harnessed for industrial and societal use. The expertise and core competence developed over the years need to be sustained through interactions among researchers as well as nurturing of new research efforts. The Annual Plasma Symposiums have eminently worked towards achievement of that purpose. Like all years, Plasma - 2008 is built around the entire national effort in this field with a special focus on 'Plasmas in Nuclear Fuel Cycle (PANFC)'. The program includes several plenary lectures, invited talks and contributed papers. The manuscripts have been peer reviewed and compiled in the form of Conference Proceedings. I am sure that the online proceedings will be useful and serve as a valuable reference material for active researchers in this field. I would like to take this opportunity to gratefully acknowledge the help and guidance of the National Advisory Committee Chaired by Professor P K Kaw, Director, Institute of Plasma Research, Gandhinagar during the organization of this symposium. My sincere thanks to Dr S Banerjee, Director, Bhabha Atomic Research Center, an acknowledged expert in the field of Materials Science and Technology, for delivering the key note address to set the tenor of the symposium. I would also like to thank the Plasma Science Society of India (PSSI) for agreeing to hold this important event at BARC. Thanks are due to Dr L M Gantayet, Director, BTDG, BARC and chairman, Scientific Program Committee and all my colleagues in the Symposium Organizing Committee who have made this symposium possible. Finally, our thanks to all the Funding agencies, Board of Research in Nuclear Science, Department of Science and Technology, The Board of Fusion Research, and all industrial exhibitor and sponsors for their unstinted support and encouragement. Dr A K Das Chairman, Organizing Committee Bhabha Atomic Research Center, Mumbai

University of Rochester, Laboratory for Laser Energetics

NASA Astrophysics Data System (ADS)

1987-01-01

In FY86 the Laboratory has produced a list of accomplishments in which it takes pride. LLE has met every laser-fusion program milestone to date in a program of research for direct-drive ultraviolet laser fusion originally formulated in 1981. LLE scientists authored or co-authored 135 scientific papers during 1985 to 1986. The collaborative experiments with NRL, LANL, and LLNL have led to a number of important ICF results. The cryogenic target system developed by KMS Fusion for LLE will be used in future high-density experiments on OMEGA to demonstrate the compression of thermonuclear fuel to 100 to 200 times that of solid (20 to 40 g/cm) in a test of the direct-drive concept, as noted in the National Academy of Sciences' report. The excellence of the advanced technology efforts at LLE is illustrated by the establishment of the Ultrafast Science Center by the Department of Defense through the Air Force Office of Scientific Research. Research in the Center will concentrate on bridging the gap between high-speed electronics and ultrafast optics by providing education, research, and development in areas critical to future communications and high-speed computer systems. The Laboratory for Laser Energetics continues its pioneering work on the interaction of intense radiation with matter. This includes inertial-fusion and advanced optical and optical electronics research; training people in the technology and applications of high-power, short-pulse lasers; and interacting with the scientific community, business, industry, and government to promote the growth of laser technology.

The effect of relativistic Compton scattering on thermonuclear burn of pure deuterium fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghasemizad, A.; Nazirzadeh, M.; Khanbabaei, B.

The relativistic effects of the Compton scattering on the thermonuclear burn-up of pure deuterium fuel in non-equilibrium plasma have been studied by four temperature (4T) theory. In the limit of low electron temperatures and photon energies, the nonrelativistic Compton scattering is valid and a convenient approximation, but in the high energy exchange rates between electrons and photons, is seen to break down. The deficiencies of the nonrelativistic approximation can be overcome by using the relativistic correction in the photons kinetic equation. In this research, we have utilized the four temperature (4T) theory to calculate the critical burn-up parameter for puremore » deuterium fuel, while the Compton scattering is considered as a relativistic phenomenon. It was shown that the measured critical burn-up parameter in ignition with relativistic Compton scattering is smaller than that of the parameter in the ignition with the nonrelativistic Compton scattering.« less

The simulations of indirect-drive targets for ignition on megajoule lasers.

NASA Astrophysics Data System (ADS)

Lykov, Vladimir; Andreev, Eugene; Ardasheva, Ludmila; Avramenko, Michael; Chernyakov, Valerian; Chizhkov, Maxim; Karlykhanov, Nikalai; Kozmanov, Michael; Lebedev, Serge; Rykovanov, George; Seleznev, Vladimir; Sokolov, Lev; Timakova, Margaret; Shestakov, Alexander; Shushlebin, Aleksander

2013-10-01

The calculations were performed with use of radiation hydrodynamic codes developed in RFNC-VNIITF. The analysis of published calculations of indirect-drive targets to obtain ignition on NIF and LMJ lasers has shown that these targets have very low margins for ignition: according to 1D-ERA code calculations it could not be ignited under decreasing of thermonuclear reaction rate less than in 2 times.The purpose of new calculations is search of indirect-drive targets with the raised margins for ignition. The calculations of compression and thermonuclear burning of targets are carried out for conditions of X-ray flux asymmetry obtained in simulations of Rugby hohlraum that were performed with 2D-SINARA code. The requirements to accuracy of manufacturing and irradiation symmetry of targets were studied with use of 2D-TIGR-OMEGA-3T code. The necessity of performed researches is caused by the construction of magajoule laser in Russia.

Cosmic Chandlery with thermonuclear supernovae

DOE PAGES

Calder, Alan C.; Krueger, Brendan K.; Jackson, A. P.; ...

2017-05-30

Thermonuclear (Type Ia) supernovae are bright stellar explosions, the light curves of which can be calibrated to allow for use as "standard candles" for measuring cosmological distances. Contemporary research investigates how the brightness of an event may be influenced by properties of the progenitor system that follow from properties of the host galaxy such as composition and age. The goals are to better understand systematic effects and to assess the intrinsic scatter in the brightness, thereby reducing uncertainties in cosmological studies. We present the results from ensembles of simulations in the single-degenerate paradigm addressing the influence of age and metallicitymore » on the brightness of an event and compare our results to observed variations of brightness that correlate with properties of the host galaxy. As a result, we also present results from "hybrid" progenitor models that incorporate recent advances in stellar evolution.« less

Current drive at plasma densities required for thermonuclear reactors.

PubMed

Cesario, R; Amicucci, L; Cardinali, A; Castaldo, C; Marinucci, M; Panaccione, L; Santini, F; Tudisco, O; Apicella, M L; Calabrò, G; Cianfarani, C; Frigione, D; Galli, A; Mazzitelli, G; Mazzotta, C; Pericoli, V; Schettini, G; Tuccillo, A A

2010-08-10

Progress in thermonuclear fusion energy research based on deuterium plasmas magnetically confined in toroidal tokamak devices requires the development of efficient current drive methods. Previous experiments have shown that plasma current can be driven effectively by externally launched radio frequency power coupled to lower hybrid plasma waves. However, at the high plasma densities required for fusion power plants, the coupled radio frequency power does not penetrate into the plasma core, possibly because of strong wave interactions with the plasma edge. Here we show experiments performed on FTU (Frascati Tokamak Upgrade) based on theoretical predictions that nonlinear interactions diminish when the peripheral plasma electron temperature is high, allowing significant wave penetration at high density. The results show that the coupled radio frequency power can penetrate into high-density plasmas due to weaker plasma edge effects, thus extending the effective range of lower hybrid current drive towards the domain relevant for fusion reactors.

Method of achieving the controlled release of thermonuclear energy

DOEpatents

Brueckner, Keith A.

1986-01-01

A method of achieving the controlled release of thermonuclear energy by illuminating a minute, solid density, hollow shell of a mixture of material such as deuterium and tritium with a high intensity, uniformly converging laser wave to effect an extremely rapid build-up of energy in inwardly traveling shock waves to implode the shell creating thermonuclear conditions causing a reaction of deuterons and tritons and a resultant high energy thermonuclear burn. Utilizing the resulting energy as a thermal source and to breed tritium or plutonium. The invention also contemplates a laser source wherein the flux level is increased with time to reduce the initial shock heating of fuel and provide maximum compression after implosion; and, in addition, computations and an equation are provided to enable the selection of a design having a high degree of stability and a dependable fusion performance by establishing a proper relationship between the laser energy input and the size and character of the selected material for the fusion capsule.

Thermonuclear Power Engineering: 60 Years of Research. What Comes Next?

NASA Astrophysics Data System (ADS)

Strelkov, V. S.

2017-12-01

This paper summarizes results of more than half a century of research of high-temperature plasmas heated to a temperature of more than 100 million degrees (104 eV) and magnetically insulated from the walls. The energy of light-element fusion can be used for electric power generation or as a source of fissionable fuel production (development of a fusion neutron source—FNS). The main results of studies of tokamak plasmas which were obtained in the Soviet Union with the greatest degree of thermal plasma isolation among all other types of devices are presented. As a result, research programs of other countries were redirected to tokamaks. Later, on the basis of the analysis of numerous experiments, the international fusion community gradually came to an opinion that it is possible to build a tokamak (ITER) with Q > 1 (where Q is the ratio of the fusion power to the external power injected into the plasma). The ITER program objective is to achieve Q = 1-10 for a discharge time of up to 1000 s. The implementation of this goal does not solve the problem of a steadystate operation. The solution to this problem is a reliable first wall and current generation. This is a task of the next fusion power plant construction stage, called DEMO. Comparison of DEMO and FNS parameters shows that, at this development stage, the operating parameters and conditions of these devices are identical.

Contributions to the NUCLEI SciDAC-3 Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bogner, Scott; Nazarewicz, Witek

This is the Final Report for Michigan State University for the NUCLEI SciDAC-3 project. The NUCLEI project, as defined by the scope of work, has developed, implemented and run codes for large-scale computations of many topics in low-energy nuclear physics. Physics studied included the properties of nuclei and nuclear decays, nuclear structure and reactions, and the properties of nuclear matter. The computational techniques used included Configuration Interaction, Coupled Cluster, and Density Functional methods. The research program emphasized areas of high interest to current and possible future DOE nuclear physics facilities, including ATLAS at ANL and FRIB at MSU (nuclear structuremore » and reactions, and nuclear astrophysics), TJNAF (neutron distributions in nuclei, few body systems, and electroweak processes), NIF (thermonuclear reactions), MAJORANA and FNPB (neutrinoless double-beta decay and physics beyond the Standard Model), and LANSCE (fission studies).« less

Nuclear Computational Low Energy Initiative (NUCLEI)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reddy, Sanjay K.

This is the final report for University of Washington for the NUCLEI SciDAC-3. The NUCLEI -project, as defined by the scope of work, will develop, implement and run codes for large-scale computations of many topics in low-energy nuclear physics. Physics to be studied include the properties of nuclei and nuclear decays, nuclear structure and reactions, and the properties of nuclear matter. The computational techniques to be used include Quantum Monte Carlo, Configuration Interaction, Coupled Cluster, and Density Functional methods. The research program will emphasize areas of high interest to current and possible future DOE nuclear physics facilities, including ATLAS andmore » FRIB (nuclear structure and reactions, and nuclear astrophysics), TJNAF (neutron distributions in nuclei, few body systems, and electroweak processes), NIF (thermonuclear reactions), MAJORANA and FNPB (neutrino-less double-beta decay and physics beyond the Standard Model), and LANSCE (fission studies).« less

Where there is a wind, there is a way

NASA Technical Reports Server (NTRS)

Mosher, C. A.

1973-01-01

A shift in USA energy policy from oil or natural gases to thermonuclear fission and solar energy is predicted. A massive diversified energy research and development effort to productively harness the energy in the winds is outlined to develop commercially feasible wind energy conversion systems - considered a form of solar energy - in the near future.

Epidemiology of a thermonuclear bomb-burst over Nashville, Tennessee: a theoretic study.

PubMed

Quinn, R W

1983-07-01

A thermonuclear bomb explosion over any city in the world would have a devastating effect on the population and environment. For those who survive, with or without injuries, life would become primitive with little or no uncontaminated food or water, and with inadequate housing, fuel, and medical care, resulting in a breakdown of family and interpersonal relationships. This theoretic study of the potential outcome of a thermonuclear bomb-burst over Nashville, Tennessee, discusses epidemiologically the wide range of medical and psychologic effects from the direct trauma of blast and fire, widespread epidemics of otherwise controlled disease, long-term chronic illness, genetic damage, and catastrophic environmental havoc.

Merging white dwarfs and thermonuclear supernovae.

PubMed

van Kerkwijk, M H

2013-06-13

Thermonuclear supernovae result when interaction with a companion reignites nuclear fusion in a carbon-oxygen white dwarf, causing a thermonuclear runaway, a catastrophic gain in pressure and the disintegration of the whole white dwarf. It is usually thought that fusion is reignited in near-pycnonuclear conditions when the white dwarf approaches the Chandrasekhar mass. I briefly describe two long-standing problems faced by this scenario, and the suggestion that these supernovae instead result from mergers of carbon-oxygen white dwarfs, including those that produce sub-Chandrasekhar-mass remnants. I then turn to possible observational tests, in particular, those that test the absence or presence of electron captures during the burning.

Outbursts in Symbiotic Binaries

NASA Technical Reports Server (NTRS)

Sonneborn, George (Technical Monitor); Keyes, Charles

2005-01-01

A major question for symbiotic stars concerns the nature and cause of their outbursts. A small subset of symbiotics, the slow novae are fairly well established as thermonuclear events that last on the order of decades. The several symbiotic recurrent novae, which are much shorter and last on the order of months, are also thought to be thermonuclear runaways. Yet the majority of symbiotics are neither slow novae nor recurrent novae. These are the so-called classical symbiotics, many of which show outbursts whose cause is not well understood. In some cases, jets are produced in association with an outburst, therefore an investigation into the causes of outbursts will yield important insights into the production of collimated outflows. To investigate the cause and nature of classical symbiotic outbursts, we initiated a program of multiwavelength observations of these events. In FUSE Cycle 2, we obtained six observational epochs of the 2000-2002 classic symbiotic outburst in the first target of our campaign - class prototype, Z Andromedae. That program was part of a coordinated multi-wavelength Target-of-Opportunity (TOO) campaign with FUSE, XMM, Chandra, MERLIN, the VLA, and ground-based spectroscopic and high time-resolution photometric observations. Our campaign proved the concept, utility, and need for coordinated multi-wavelength observations in order to make progress in understanding the nature of the outburst mechanisms in symbiotic stars. Indeed, the FUSE data were the cornerstone of this project

Epidemiology of a thermonuclear bomb-burst over Nashville, Tennessee: a theoretic study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quinn, R.W.

1983-07-01

A thermonuclear bomb explosion over any city in the world would have a devastating effect on the population and environment. For those who survive, with or without injuries, life would become primitive with little or no uncontaminated food or water, and with inadequate housing, fuel, and medical care, resulting in a breakdown of family and interpersonal relationships. This theoretic study of the potential outcome of a thermonuclear bomb-burst over Nashville, Tennessee, discusses epidemiologically the wide range of medical and psychologic effects from the direct trauma of blast and fire, widespread epidemics of otherwise controlled disease, long-term chronic illness, genetic damage,more » and catastrophic environmental havoc.« less

Thermonuclear 19F(p, {{\\boldsymbol{\\alpha }}}_{0})16O reaction rate

NASA Astrophysics Data System (ADS)

He, Jian-Jun; Lombardo, Ivano; Dell'Aquila, Daniele; Xu, Yi; Zhang, Li-Yong; Liu, Wei-Ping

2018-01-01

The thermonuclear 19F(p, {{{α }}}0)16O reaction rate in the temperature region 0.007-10 GK has been derived by re-evaluating the available experimental data, together with the low-energy theoretical R-matrix extrapolations. Our new rate deviates by up to about 30% compared to the previous results, although all rates are consistent within the uncertainties. At very low temperature (e.g. 0.01 GK) our reaction rate is about 20% lower than the most recently published rate, because of a difference in the low energy extrapolated S-factor and a more accurate estimate of the reduced mass used in the calculation of the reaction rate. At temperatures above ˜1 GK, our rate is lower, for instance, by about 20% around 1.75 GK, because we have re-evaluated the previous data (Isoya et al., Nucl. Phys. 7, 116 (1958)) in a meticulous way. The present interpretation is supported by the direct experimental data. The uncertainties of the present evaluated rate are estimated to be about 20% in the temperature region below 0.2 GK, and are mainly caused by the lack of low-energy experimental data and the large uncertainties in the existing data. Asymptotic giant branch (AGB) stars evolve at temperatures below 0.2 GK, where the 19F(p, {{α }})16O reaction may play a very important role. However, the current accuracy of the reaction rate is insufficient to help to describe, in a careful way, the fluorine over-abundances observed in AGB stars. Precise cross section (or S factor) data in the low energy region are therefore needed for astrophysical nucleosynthesis studies. Supported by National Natural Science Foundation of China (11490562, 11490560, 11675229) and National Key Research and Development Program of China (2016YFA0400503)

Gamma-Ray Effects Testing in Lawrence Livermore National Laboratory’s Nova Upgrade Facility

DTIC Science & Technology

1992-03-01

However, the distribution of energy between neutrons and photons from the ICF pellet will be different then that from a thermonuclear bomb . In a...of the neutron energy to photons. Photons make up most of the energy released from a thermonuclear bomb (Glasstone, S., 1977:340-342). The neutrons

Rocket propulsion by thermonuclear micro-bombs ignited with intense relativistic electron beams.

NASA Technical Reports Server (NTRS)

Winterberg, F.

1971-01-01

Discussion of a method for the ignition of a thermonuclear microbomb by means of an intense relativistic electron beam with regard to its potential application to rocket propulsion. With such a system, exhaust velocities up to 1000 km/sec, corresponding to a specific impulse of 100,000 sec, seem to be within the realm of possibility. The rocket is propelled by a chain of thermonuclear microbombs exploded in a concave magnetic mirror produced by superconducting field coils. The magnetic pressure of the field reflects the fireball generated by the explosion. For the large capacitor bank required to generate the intense relativistic electron beam, a desirable lightweight design may be possible through use of ferroelectric materials. Because of the high cost of the T-D and He 3-D thermonuclear material, the system has to be optimized by minimizing the T-D and He 3-D consumption by a proper TD and He 3-D fuel to hydrogen propellant mass ratio, leading to a larger total system mass than would be absolutely necessary.

The comparison of extraction of energy in two-cascade and one-cascade targets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dolgoleva, G. V., E-mail: dolgg@list.ru; Ponomarev, I. V., E-mail: wingof17@mail.ru

2016-01-15

The paper is devoted to numerical designing of cylindrical microtargets on the basis of shock-free compression. When designing microtargets for the controlled thermonuclear fusion, the core tasks are to select geometry and make-up of layers, and the law of energy embedding as well, which allow receiving of “burning” of deuterium- tritium mix, that is, the existence of thermonuclear reactions of working area. Yet, the energy yield as a result of thermonuclear reactions has to be more than the embedded energy (the coefficient of amplification is more than a unit). So, an important issue is the value of the embedded energy.more » The purpose of the present paper is to study the extraction of energy by working DT area in one-cascade and two-cascade targets. A bigger extraction of energy will contribute to a better burning of DT mix and a bigger energy yield as a result of thermonuclear reactions. The comparison of analytical results to numerical calculations is carried out. The received results show advantages of a two-cascade target compared to a one-cascade one.« less

FAILURE OF A NEUTRINO-DRIVEN EXPLOSION AFTER CORE-COLLAPSE MAY LEAD TO A THERMONUCLEAR SUPERNOVA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kushnir, Doron; Katz, Boaz, E-mail: kushnir@ias.edu

We demonstrate that ∼10 s after the core-collapse of a massive star, a thermonuclear explosion of the outer shells is possible for some (tuned) initial density and composition profiles, assuming that the neutrinos failed to explode the star. The explosion may lead to a successful supernova, as first suggested by Burbidge et al. We perform a series of one-dimensional (1D) calculations of collapsing massive stars with simplified initial density profiles (similar to the results of stellar evolution calculations) and various compositions (not similar to 1D stellar evolution calculations). We assume that the neutrinos escaped with a negligible effect on themore » outer layers, which inevitably collapse. As the shells collapse, they compress and heat up adiabatically, enhancing the rate of thermonuclear burning. In some cases, where significant shells of mixed helium and oxygen are present with pre-collapsed burning times of ≲100 s (≈10 times the free-fall time), a thermonuclear detonation wave is ignited, which unbinds the outer layers of the star, leading to a supernova. The energy released is small, ≲10{sup 50} erg, and negligible amounts of synthesized material (including {sup 56}Ni) are ejected, implying that these 1D simulations are unlikely to represent typical core-collapse supernovae. However, they do serve as a proof of concept that the core-collapse-induced thermonuclear explosions are possible, and more realistic two-dimensional and three-dimensional simulations are within current computational capabilities.« less

Accretion Disks and Coronae in the X-Ray Flashlight

NASA Astrophysics Data System (ADS)

Degenaar, Nathalie; Ballantyne, David R.; Belloni, Tomaso; Chakraborty, Manoneeta; Chen, Yu-Peng; Ji, Long; Kretschmar, Peter; Kuulkers, Erik; Li, Jian; Maccarone, Thomas J.; Malzac, Julien; Zhang, Shu; Zhang, Shuang-Nan

2018-02-01

Plasma accreted onto the surface of a neutron star can ignite due to unstable thermonuclear burning and produce a bright flash of X-ray emission called a Type-I X-ray burst. Such events are very common; thousands have been observed to date from over a hundred accreting neutron stars. The intense, often Eddington-limited, radiation generated in these thermonuclear explosions can have a discernible effect on the surrounding accretion flow that consists of an accretion disk and a hot electron corona. Type-I X-ray bursts can therefore serve as direct, repeating probes of the internal dynamics of the accretion process. In this work we review and interpret the observational evidence for the impact that Type-I X-ray bursts have on accretion disks and coronae. We also provide an outlook of how to make further progress in this research field with prospective experiments and analysis techniques, and by exploiting the technical capabilities of the new and concept X-ray missions ASTROSAT, NICER, Insight-HXMT, eXTP, and STROBE-X.

Terrorist Use of the Internet and Related Information Technologies

DTIC Science & Technology

2002-05-15

the Anarchist, Vol I," 4 January 1985 [online]; available from <http://www.etext.org/CuD/Misc/anarch>. 33 See _____, "How to Build a Thermonuclear Bomb ," About...Development, no date. [Online]; previously available from <http://www.hlf.org> (accessed 6 December 2001). _____. "How to Build a Thermonuclear Bomb ." About

Reaching to a featured formula to deduce the energy of the heaviest particles producing from the controlled thermonuclear fusion reactions

NASA Astrophysics Data System (ADS)

Majeed, Raad H.; Oudah, Osamah N.

2018-05-01

Thermonuclear fusion reaction plays an important role in developing and construction any power plant system. Studying the physical behavior for the possible mechanism governed energies released by the fusion products to precise understanding the related kinematics. In this work a theoretical formula controlled the general applied thermonuclear fusion reactions is achieved to calculating the fusion products energy depending upon the reactants physical properties and therefore, one can calculate other parameters governed a given reaction. By using this formula, the energy spectrum of 4He produced from T-3He fusion reaction has been sketched with respect to reaction angle and incident energy ranged from (0.08-0.6) MeV.

Neutral atom analyzers for diagnosing hot plasmas: A review of research at the ioffe physicotechnical institute

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kislyakov, A. I.; Petrov, M. P.

2009-07-15

Research on neutral particle diagnostics of thermonuclear plasmas that has been carried out in recent years at the Ioffe Physicotechnical Institute of the Russian Academy of Sciences (St. Petersburg, Russia) is reviewed. Work on the creation and improvement of neutral atom analyzers was done in two directions: for potential applications (in particular, on the International Thermonuclear Experimental Reactor, which is now under construction at Cadarache in France) and for investigation of the ion plasma component in various devices (in particular, in the largest tokamaks, such as JET, TFTR, and JT-60). Neutral atom analyzers are the main tool for studying themore » behavior of hydrogen ions and isotopes in magnetic confinement systems. They make it possible to determine energy spectra, to perform the isotope analysis of atom fluxes from the plasma, to measure the absolute intensity of the fluxes, and to record how these parameters vary with time. A comparative description of the analyzers developed in recent years at the Ioffe Institute is given. These are ACORD-12/24 analyzers for recording 0.2-100-keV hydrogen and deuterium atoms with a tunable range of simultaneously measured energies, CNPA compact analyzers for a fixed energy gain in the ranges 80-1000 eV and 0.8-100 keV, an ISEP analyzer for simultaneously recording the atoms of all the three hydrogen isotopes (H, D, and T) in the energy range 5-700 keV, and GEMMA analyzers for recording atom fluxes of hydrogen and helium isotopes in the range 0.1-4 MeV. The scintillating detectors of the ISEP and GEMMA analyzers have a lowered sensitivity to neutrons and thus can operate without additional shielding in neutron fields of up to 10{sup 9} n/(cm{sup 2} s). These two types of analyzers, intended to operate under deuterium-tritium plasma conditions, are prototypes of atom analyzers created at the Ioffe Institute for use in the International Thermonuclear Experimental Reactor. With these analyzers, a number of new results have been obtained in recent years in various devices. Some results are presented from investigation of ions in the Globus-M spherical tokamak, the W7-AS stellarator, and the JET tokamak by means of the analyzers developed at the Ioffe Institute. Challenges and opportunities for applying these diagnostics in the International Thermonuclear Experimental Reactor project are discussed.« less

Chemically ignited thermonuclear reactions—A near-term means for a high specific impulse—High thrust propulsion system

NASA Astrophysics Data System (ADS)

Winterberg, F.

The combination of metallic shells imploded with chemical explosives and the recently proposed magnetic booster target inertial fusion concept, could make possible the fissionless ignition of small thermonuclear explosions. In the magnetic booster concept a very dense but magnetically confined thermonuclear plasma of low yield serves as the trigger for an inertially confined thermonuclear plasma of high yield. For the most easily ignitable fusion reaction, the DT reaction, this could lead to a fissionless bomb propulsion system, with the advantage to have a much smaller yield of the pure fusion bombs as compared to either fission- or fission-induced fusion bombs, previously proposed for propulsion. Typically, the proposed propulsion concept should give a specific impulse of ˜ 3000 secs, corresponding to an exhaust velocity of ˜ 30 km/sec. If the energy released in each pure fusion bomb is of the order of 10 18 erg or the order of 100 tons of TNT, and if one fusion explosion per second takes place, the average thrust is of the order 10 3 tons. The propulsion system appears ideally suited for the fast economical transport of large spacecraft within the solar system.

Use of liquid metals in nuclear and thermonuclear engineering, and in other innovative technologies

NASA Astrophysics Data System (ADS)

Rachkov, V. I.; Arnol'dov, M. N.; Efanov, A. D.; Kalyakin, S. G.; Kozlov, F. A.; Loginov, N. I.; Orlov, Yu. I.; Sorokin, A. P.

2014-05-01

By now, a good deal of experience has been gained with using liquid metals as coolants in nuclear power installations; extensive knowledge has been gained about the physical, thermophysical, and physicochemical properties of these coolants; and the scientific principles and a set of methods and means for handling liquid metals as coolants for nuclear power installations have been elaborated. Prototype and commercialgrade sodium-cooled NPP power units have been developed, including the BOR-60, BN-350, and BN-600 power units (the Soviet Union); the Rapsodie, Phenix, and Superphenix power units (France), the EBR-II power unit (the United States); and the PFR power unit (the United Kingdom). In Russia, dedicated nuclear power installations have been constructed, including those with a lead-bismuth coolant for nuclear submarines and with sodium-potassium alloy for spacecraft (the Buk and Topol installations), which have no analogs around the world. Liquid metals (primarily lithium and its alloy with lead) hold promise for use in thermonuclear power engineering, where they can serve not only as a coolant, but also as tritium-producing medium. In this article, the physicochemical properties of liquid metal coolants, as well as practical experience gained from using them in nuclear and thermonuclear power engineering and in innovative technologies are considered, and the lines of further research works are formulated. New results obtained from investigations carried out on the Pb-Bi and Pb for the SVBR and BREST fast-neutron reactors (referred to henceforth as fast reactors) and for controlled accelerator systems are described.

Oscillations During Thermonuclear X-ray Bursts: A New Probe of Neutron Stars

NASA Technical Reports Server (NTRS)

Strohmayer, Tod E.; White, Nicholas E. (Technical Monitor)

2002-01-01

Observations of thermonuclear (also called Type 1) X-ray bursts from neutron stars in low mass X-ray binaries (LMXB) with the Rossi X-ray Timing Explorer (RXTE) have revealed large amplitude, high coherence X-ray brightness oscillations with frequencies in the 300 - 600 Hz range. Substantial spectral and timing evidence point to rotational modulation of the X-ray burst flux as the cause of these oscillations, and it is likely that they reveal the spin frequencies of neutron stars in LMXB from which they are detected. Here we review the status of our knowledge of these oscillations and describe how they can be used to constrain the masses and radii of neutron stars as well as the physics of thermonuclear burning on accreting neutron stars.

U.S.-Russian Civilian Nuclear Cooperation Agreement: Issues for Congress

DTIC Science & Technology

2010-07-09

for nuclear cooperation in 1973 to allow for cooperation in controlled thermonuclear fusion, fast breeder reactors , and fundamental research. The...that a 123 agreement is needed to implement this action plan—for example, full scale technical cooperation on fast reactors and demonstration of...superpowers convened a Joint Coordinating Committee for Civilian Reactor Safety starting in 1988.10 After the fall of the Soviet Union and prior to July

Outbursts in Symbiotic Binaries: Z and Continued Observation

NASA Technical Reports Server (NTRS)

Sonneborn, George (Technical Monitor); Keyes, Charles

2005-01-01

A major question for symbiotic stars concerns the nature and cause of their outbursts. A small subset of symbiotics, the "slow novae" are fairly well established as thermonuclear events that last on the order of decades. The several symbiotic "recurrent novae", which are much shorter and last on the order of months, are also thought to be thermonuclear runaways. Yet the majority of symbiotics are neither slow novae nor recurrent novae. These are the so-called "classical symbiotics," many of which show outbursts whose cause is not well understood. In some cases, jets are produced in association with an outburst, therefore an investigation into the causes of outbursts will yield important insights into the production of collimated outflows. To investigate the cause and nature of classical symbiotic outbursts, we initiated a program of multi- wavelength observations of these events. First of all in FUSE Cycle 2, we obtained six observational epochs of the 2000-2002 classic symbiotic outburst in the first target of our campaign - class prototype, Z Andromedae. That program was part of a coordinated multi-wavelength Target-of-Opportunity (TOO) campaign with FUSE, XMM, Chandra, MERLIN, the VLA, and ground-based spectroscopic and high time-resolution photometric observations. Our campaign proved the concept, utility, and need for coordinated multi-wavelength observations in order to make progress in understanding the nature of the outburst mechanisms in symbiotic stars. Indeed, the FUSE data were the cornerstone of this project. The present program is a continuation of that cycle 2 effort. Indeed, the observations acquired in this program are vital to the proper interpretation of the material acquired in cycle 2 as the new data cover the critical time period when the star continues to decline from outburst and actually returns to quiescence. The utilization of these data have allowed us to refine and complete description of our new model for classical symbiotic system outbursts.

Shock ignition of thermonuclear fuel with high areal density.

PubMed

Betti, R; Zhou, C D; Anderson, K S; Perkins, L J; Theobald, W; Solodov, A A

2007-04-13

A novel method by C. Zhou and R. Betti [Bull. Am. Phys. Soc. 50, 140 (2005)] to assemble and ignite thermonuclear fuel is presented. Massive cryogenic shells are first imploded by direct laser light with a low implosion velocity and on a low adiabat leading to fuel assemblies with large areal densities. The assembled fuel is ignited from a central hot spot heated by the collision of a spherically convergent ignitor shock and the return shock. The resulting fuel assembly features a hot-spot pressure greater than the surrounding dense fuel pressure. Such a nonisobaric assembly requires a lower energy threshold for ignition than the conventional isobaric one. The ignitor shock can be launched by a spike in the laser power or by particle beams. The thermonuclear gain can be significantly larger than in conventional isobaric ignition for equal driver energy.

A Game Theoretic Model of Thermonuclear Cyberwar

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soper, Braden C.

In this paper we propose a formal game theoretic model of thermonuclear cyberwar based on ideas found in [1] and [2]. Our intention is that such a game will act as a first step toward building more complete formal models of Cross-Domain Deterrence (CDD). We believe the proposed thermonuclear cyberwar game is an ideal place to start on such an endeavor because the game can be fashioned in a way that is closely related to the classical models of nuclear deterrence [4–6], but with obvious modifications that will help to elucidate the complexities introduced by a second domain. We startmore » with the classical bimatrix nuclear deterrence game based on the game of chicken, but introduce uncertainty via a left-of-launch cyber capability that one or both players may possess.« less

Inertial Confinement Fusion Annual Report 1997

DOE Office of Scientific and Technical Information (OSTI.GOV)

Correll, D

The ICF Annual Report provides documentation of the achievements of the LLNL ICF Program during the fiscal year by the use of two formats: (1) an Overview that is a narrative summary of important results for the fiscal year and (2) a compilation of the articles that previously appeared in the ICF Quarterly Report that year. Both the Overview and Quarterly Report are also on the Web at http://lasers.llnl.gov/lasers/pubs/icfq.html. Beginning in Fiscal Year 1997, the fourth quarter issue of the ICF Quarterly was no longer printed as a separate document but rather included in the ICF Annual. This change providedmore » a more efficient process of documenting our accomplishments with-out unnecessary duplication of printing. In addition we introduced a new document, the ICF Program Monthly Highlights. Starting with the September 1997 issue and each month following, the Monthly Highlights will provide a brief description of noteworthy activities of interest to our DOE sponsors and our stakeholders. The underlying theme for LLNL's ICF Program research continues to be defined within DOE's Defense Programs missions and goals. In support of these missions and goals, the ICF Program advances research and technology development in major interrelated areas that include fusion target theory and design, target fabrication, target experiments, and laser and optical science and technology. While in pursuit of its goal of demonstrating thermonuclear fusion ignition and energy gain in the laboratory, the ICF Program provides research and development opportunities in fundamental high-energy-density physics and supports the necessary research base for the possible long-term application of inertial fusion energy for civilian power production. ICF technologies continue to have spin-off applications for additional government and industrial use. In addition to these topics, the ICF Annual Report covers non-ICF funded, but related, laser research and development and associated applications. We also provide a short summary of the quarterly activities within Nova laser operations, Beamlet laser operations, and National Ignition Facility laser design. LLNL's ICF Program falls within DOE's national ICF program, which includes the Nova and Beamlet (LLNL), OMEGA (University of Rochester Laboratory for Laser Energetics), Nike (Naval Research Laboratory), and Trident (Los Alamos National Laboratory) laser facilities. The Particle Beam Fusion Accelerator (Z) and Saturn pulsed-power facilities are at Sandia National Laboratories. General Atomics, Inc., develops and provides many of the targets for the above experimental facilities. Many of the ICF Annual Report articles are co-authored with our colleagues from these other ICF institutions.« less

Thermonuclear runaways in nova outbursts

NASA Technical Reports Server (NTRS)

Shankar, Anurag; Arnett, David; Fryxell, Bruce A.

1992-01-01

Results of exploratory, two-dimensional numerical calculations of a local thermonuclear runaway on the surface of a white dwarf are reported. It is found that the energy released by the runaway can induce a significant amount of vorticity near the burning region. Such mass motions account naturally for mixing of core matter into the envelope during the explosion. A new mechanism for the lateral spread of nuclear burning is also discussed.

AC Josephson effect applications in microwave systems

NASA Astrophysics Data System (ADS)

Larkin, Serguey Y.

1996-12-01

A complication of the tasks solving by the modem radliolocation, radionavigation and communication systems connected with the demand promotion to the resolution and accuracy of coordinates definition and increase in the volumes of transmitted information in satellite communication systems has resulted in boisterous mastering of millimeter wave bands. Success in microwave technology reached in 80' allowed such leading instrument developing companies as Hewlett Packard; EIP, lB millimeter etc. to set up an output of mm- and submm-wave bands devices and systems. It has streamlined Scientific Technological Progress in several spheres, since millimeter, through infra-red frequency range was closed to researchers for a long period of time because of the absence of necessary equipment. At present microwave devices of the short-wave part of mm- wave band and of submm- wave bands are used not only in radiolocation and communications. Unique diagnostic systems based on the analysis of the radiation parameters of different microwave sources were created. They have their application in medicine, thermonuclear energetics, radioastronomy, biology, nuclear physics, the physics of the solid state body, geology, etc. The above circumstances caused the beginning of the measuring microwave technology researches in 60 to 600 GHz frequency range: generators, power and frequency meters, spectrum analyzers. The task of working out equipment and techniques of the effective control as well as frequency and intensity measurements of the microwave signals in the investigated range is of the special interest. Here are some examples. The creation of a thermonuclear reactor in ITER project is considered to be the project of the century in the energetics sphere. One of the basic engineering tasks in the course of project realization is the creation of the diagnostic equipment realizing in real time spectrum analysis of thermonuclear plasma radiation at the so called cyclotron hannonics. Such analysis allow to get the picture of temperature distribution along the plasma cord diameter in accordance with dynamics of thermonuclear process development. Modem raclioastronomic research gives scientists the unique information on the world tructure. It is also necessary to analyze Space microwave radiation providing exclusive sensitivity of the equipment. In both cases equipment is required to be superwide band, to have high sensitivity and ability to operate at more than 300 GHz frequencies. Today all these requirements are met by the devices using the ac Josephson effect. The Josephson junctions are used as an active transforming element in such devices. At the end of 20 century the sphere of their utilization embraces medicine, communications, radiophysics, space exploration, ecology, military use, etc. The State Research Center "Fonon" ( SRC "Fonon") of the State Committee on Science and Technology of Ukraine was founded in 1991. The main aim of its creation was to concentrate the scientific and financial efforts for development and production of unique devices based on the results of fundamental study in physics of high T superconductivity. First of all we were interested in technological research on the obtaining of low impedance Josephson junctions out of the High T thin films. Using such junctions in combination with our original techniques developed in our Center we have succeed in creating the following new generation equipment: industrial set-up of the frequency meter in the range of 60 ... 600 GHz; experimental set-up of the spectrum analyzer operating in the range of 50 250 GHz; experimental model of radiometric receiver in 180...260 GHz range. All the above devices are based on the using ac Josephson effect for the receiving and processing mm- and submm- microwave signals.

Recent progress in understanding the eruptions of classical novae

NASA Technical Reports Server (NTRS)

Shara, Michael M.

1988-01-01

Dramatic progress has occurred in the last two decades in understanding the physical processes and events leading up to, and transpiring during the eruption of a classical nova. The mechanism whereby a white dwarf accreting hydrogen-rich matter from a low-mass main-sequence companion produces a nova eruption has been understood since 1970. The mass-transferring binary stellar configuration leads inexorably to thermonuclear runaways detected at distances of megaparsecs. Summarized here are the efforts of many researchers in understanding the physical processes which generate nova eruptions; the effects upon nova eruptions of different binary-system parameters (e.g., chemical composition or mass of the white dwarf, different mass accretion rates); the possible metamorphosis from dwarf to classical novae and back again; and observational diagnostics of novae, including x ray and gamma ray emission, and the characteristics and distributions of novae in globular clusters and in extragalactic systems. While the thermonuclear-runaway model remains the successful cornerstone of nova simulation, it is now clear that a wide variety of physical processes, and three-dimensional hydrodynamic simulations, will be needed to explain the rich spectrum of behavior observed in erupting novae.

Tokamaks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wesson, J

1987-01-01

The word tokamak derives from the Russian term, toroidalnaya kamera magnitaya (toroidal chamber magnetic). The device was invented in the Soviet Union in 1950 and has since developed into one of the chief ways in which it is hoped to obtain usable power from plasmas through thermonuclear fusion. The present is meant to be an introduction to those entering the field, to those already engaged in research, and to those who want to gain some understanding of what it's all about.

Publicly Released Prompt Radiation Spectra Suitable for Nuclear Detonation Simulations

DTIC Science & Technology

2017-03-01

emission. During the Hiroshima and Nagasaki bombings , the prompt radiation contributed from 40%-70% of the free-in-air dose depending on distance from...intermediate- and low-yield thermonuclear weapons for initial radiation shielding calculations No Gritzner, et al. 1976 ( EM -1, Low, Henre...DNA 4267F ( EM -1 Fission) Neutron Gritzner, et al. 1976 1.00 x 1023 Glasstone (Thermonuclear) Neutron Glasstone & Dolan 1977 1.445 x 1023 ORNL-TM

Fusion yield: Guderley model and Tsallis statistics

NASA Astrophysics Data System (ADS)

Haubold, H. J.; Kumar, D.

2011-02-01

The reaction rate probability integral is extended from Maxwell-Boltzmann approach to a more general approach by using the pathway model introduced by Mathai in 2005 (A pathway to matrix-variate gamma and normal densities. Linear Algebr. Appl. 396, 317-328). The extended thermonuclear reaction rate is obtained in the closed form via a Meijer's G-function and the so-obtained G-function is represented as a solution of a homogeneous linear differential equation. A physical model for the hydrodynamical process in a fusion plasma-compressed and laser-driven spherical shock wave is used for evaluating the fusion energy integral by integrating the extended thermonuclear reaction rate integral over the temperature. The result obtained is compared with the standard fusion yield obtained by Haubold and John in 1981 (Analytical representation of the thermonuclear reaction rate and fusion energy production in a spherical plasma shock wave. Plasma Phys. 23, 399-411). An interpretation for the pathway parameter is also given.

Results from MARBLE DT Experiments on the National Ignition Facility: Implosion of Foam-Filled Capsules for Studying Thermonuclear Burn in the Presence of Heterogeneous Mix

NASA Astrophysics Data System (ADS)

Murphy, T. J.; Douglas, M. R.; Cardenas, T.; Cooley, J. H.; Gunderson, M. A.; Haines, B. M.; Hamilton, C. E.; Kim, Y.; Lee, M. N.; Oertel, J. A.; Olson, R. E.; Randolph, R. B.; Shah, R. C.; Smidt, J. M.

2017-10-01

The MARBLE campaign on NIF investigates the effect of heterogeneous mix on thermonuclear burn for comparison to a probability distribution function (PDF) burn model. MARBLE utilizes plastic capsules filled with deuterated plastic foam and tritium gas. The ratio of DT to DD neutron yield is indicative of the degree to which the foam and the gas atomically mix. Platform development experiments have been performed to understand the behavior of the foam and of the gas separately using two types of capsule. The first experiments using deuterated foam and tritium gas have been performed. Results of these experiments, and the implications for our understanding of thermonuclear burn in heterogeneously mixed separated reactant experiments will be discussed. This work is supported by US DOE/NNSA, performed at LANL, operated by LANS LLC under contract DE-AC52-06NA25396.

On thermonuclear ignition criterion at the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Baolian; Kwan, Thomas J. T.; Wang, Yi-Ming

2014-10-15

Sustained thermonuclear fusion at the National Ignition Facility remains elusive. Although recent experiments approached or exceeded the anticipated ignition thresholds, the nuclear performance of the laser-driven capsules was well below predictions in terms of energy and neutron production. Such discrepancies between expectations and reality motivate a reassessment of the physics of ignition. We have developed a predictive analytical model from fundamental physics principles. Based on the model, we obtained a general thermonuclear ignition criterion in terms of the areal density and temperature of the hot fuel. This newly derived ignition threshold and its alternative forms explicitly show the minimum requirementsmore » of the hot fuel pressure, mass, areal density, and burn fraction for achieving ignition. Comparison of our criterion with existing theories, simulations, and the experimental data shows that our ignition threshold is more stringent than those in the existing literature and that our results are consistent with the experiments.« less

Statistical methods for thermonuclear reaction rates and nucleosynthesis simulations

NASA Astrophysics Data System (ADS)

Iliadis, Christian; Longland, Richard; Coc, Alain; Timmes, F. X.; Champagne, Art E.

2015-03-01

Rigorous statistical methods for estimating thermonuclear reaction rates and nucleosynthesis are becoming increasingly established in nuclear astrophysics. The main challenge being faced is that experimental reaction rates are highly complex quantities derived from a multitude of different measured nuclear parameters (e.g., astrophysical S-factors, resonance energies and strengths, particle and γ-ray partial widths). We discuss the application of the Monte Carlo method to two distinct, but related, questions. First, given a set of measured nuclear parameters, how can one best estimate the resulting thermonuclear reaction rates and associated uncertainties? Second, given a set of appropriate reaction rates, how can one best estimate the abundances from nucleosynthesis (i.e., reaction network) calculations? The techniques described here provide probability density functions that can be used to derive statistically meaningful reaction rates and final abundances for any desired coverage probability. Examples are given for applications to s-process neutron sources, core-collapse supernovae, classical novae, and Big Bang nucleosynthesis.

Future Probes of the Neutron Star Equation of State Using X-ray Bursts

NASA Technical Reports Server (NTRS)

Strohmayer, Tod E.

2004-01-01

Observations with NASA s Rossi X-ray Timing Explorer (RXTE) have resulted in the discovery of fast (200 - 600 Hz), coherent X-ray intensity oscillations (hereafter, %urstoscillations ) during thermonuclear X-ray bursts from 12 low mass X-ray binaries (LMXBs). Although many of their detailed properties remain to be fully understood, it is now beyond doubt that these oscillations result from spin modulation of the thermonuclear burst flux from the neutron star surface. Among the new timing phenomena revealed by RXTE the burst oscillations are perhaps the best understood, in the sense that many of their properties can be explained in the framework of this relatively simple model. Because of this, detailed modelling of burst oscillations can be an extremely powerful probe of neutron star structure, and thus the equation of state (EOS) of supra-nuclear density matter. Both the compactness parameter beta = GM/c(sup 2)R, and the surface velocity, nu(sub rot) = Omega(sub spin)R, are encoded in the energy-dependent amplitude and shape of the modulation pulses. The new discoveries have spurred much new theoretical work on thermonuclear burning and propagation on neutron stars, so that in the near future it is not unreasonable to think that detailed physical models of the time dependent flux from burning neutron stars will be available for comparison with the observed pulse profiles from a future, large collecting area X-ray timing observatory. In addition, recent high resolution burst spectroscopy with XMM/Newton suggests the presence of redshifted absorption lines from the neutron star surface during bursts. This leads to the possibility of using large area, high spectral resolution measurements of X-ray bursts as a precise probe of neutron star structure. In this work I will explore the precision with which constraints on neutron star structure, and hence the dense matter EOS, can be made with the implementation of such programs.

Remote experimental site concept development

NASA Astrophysics Data System (ADS)

Casper, Thomas A.; Meyer, William; Butner, David

1995-01-01

Scientific research is now often conducted on large and expensive experiments that utilize collaborative efforts on a national or international scale to explore physics and engineering issues. This is particularly true for the current US magnetic fusion energy program where collaboration on existing facilities has increased in importance and will form the basis for future efforts. As fusion energy research approaches reactor conditions, the trend is towards fewer large and expensive experimental facilities, leaving many major institutions without local experiments. Since the expertise of various groups is a valuable resource, it is important to integrate these teams into an overall scientific program. To sustain continued involvement in experiments, scientists are now often required to travel frequently, or to move their families, to the new large facilities. This problem is common to many other different fields of scientific research. The next-generation tokamaks, such as the Tokamak Physics Experiment (TPX) or the International Thermonuclear Experimental Reactor (ITER), will operate in steady-state or long pulse mode and produce fluxes of fusion reaction products sufficient to activate the surrounding structures. As a direct consequence, remote operation requiring robotics and video monitoring will become necessary, with only brief and limited access to the vessel area allowed. Even the on-site control room, data acquisition facilities, and work areas will be remotely located from the experiment, isolated by large biological barriers, and connected with fiber-optics. Current planning for the ITER experiment includes a network of control room facilities to be located in the countries of the four major international partners; USA, Russian Federation, Japan, and the European Community.

Improving High-Temperature Measurements in Nuclear Reactors with Mo/Nb Thermocouples

NASA Astrophysics Data System (ADS)

Villard, J.-F.; Fourrez, S.; Fourmentel, D.; Legrand, A.

2008-10-01

Many irradiation experiments performed in research reactors are used to assess the effects of nuclear radiations on material or fuel sample properties, and are therefore a crucial stage in most qualification and innovation studies regarding nuclear technologies. However, monitoring these experiments requires accurate and reliable instrumentation. Among all measurement systems implemented in irradiation devices, temperature—and more particularly high-temperature (above 1000°C)—is a major parameter for future experiments related, for example, to the Generation IV International Forum (GIF) Program or the International Thermonuclear Experimental Reactor (ITER) Project. In this context, the French Commissariat à l’Energie Atomique (CEA) develops and qualifies innovative in-pile instrumentation for its irradiation experiments in current and future research reactors. Logically, a significant part of these research and development programs concerns the improvement of in-pile high-temperature measurements. This article describes the development and qualification of innovative high-temperature thermocouples specifically designed for in-pile applications. This key study has been achieved with technical contributions from the Thermocoax Company. This new kind of thermocouple is based on molybdenum and niobium thermoelements, which remain nearly unchanged by thermal neutron flux even under harsh nuclear environments, whereas typical high-temperature thermocouples such as Type C or Type S are altered by significant drifts caused by material transmutations under the same conditions. This improvement has a significant impact on the temperature measurement capabilities for future irradiation experiments. Details of the successive stages of this development are given, including the results of prototype qualification tests and the manufacturing process.

Dust, Abundances, and the Evolution of Novae

NASA Astrophysics Data System (ADS)

Woodward, Charles; Bode, Michael; Evans, Anuerin; Geballe, Thomas; Gehrz, Robert; Helton, Andrew; Krautter, Joachim; Lynch, David; Ness, Jan-Uwe; Rudy, Richard; Schwarz, Greg; Shore, Steve; Starrfield, Sumner; Truran, James; Vanlandingham, Karen; Wagner, R. Mark

2008-03-01

Evolved stars are the engines of energy production and chemical evolution in our Universe. They deposit radiative and mechanical energy into their environments. They enrich the ambient ISM with elements synthesized in their interiors and dust grains condensed in their atmospheres. Classical novae (CNe) contribute to this cycle of chemical enrichment through explosive nucleosynthesis and the violent ejection of material dredged from the white dwarf progenitor and mixed with the accreted surface layers. Our capstone study of 10 CNe will provide an ensemble of objects, well-populated in CNe parameter space (fast, slow, 'coronal', dusty) for detailed photoionization modeling and analysis. CNe are laboratories in which several poorly-understood astrophysical processes (e.g., mass transfer, thermonuclear runaway, optically thick winds, common envelope evolution, molecule and grain formation, coronal emission) may be observed. With Spitzer's unique wavelength coverage and point-source sensitivity we can: (i) investigate the in situ formation, astromineralogy, and processing of nova dust, (ii) determine the ejecta elemental abundances resulting from thermonuclear runaway, (iii) constrain the correlation of ejecta mass with progenitor type, (iv) measure the bolometric luminosity of the outburst, and (v) characterize the kinematics and structure of the ejected envelopes. Extensive ground-based and space-based (Chandra, Swift, XMM-Newton) programs led by team CoIs will complement Spitzer CNe observations.

FROM THE HISTORY OF PHYSICS: The physics of a thermonuclear explosion of a normal-density liquefied deuterium sphere (On the impossibility of a spherically symmetric thermonuclear explosion in liquid deuterium at normal density)

NASA Astrophysics Data System (ADS)

Marchuk, Gurii I.; Imshennik, Vladimir S.; Basko, Mikhail M.

2009-03-01

The hydrodynamic problem of a thermonuclear explosion in a sphere of normal-density liquid deuterium was solved (Institute for Physics and Power Engineering, Obninsk) in 1952-1954 in the framework of the Soviet Atomic Project. The principal result was that the explosion shockwave in deuterium strongly decayed because of radiation energy loss and nonlocal energy release by fast neutrons. At that time, this negative result implied in essence that the straightforward approach to creating a thermonuclear weapon was in fact a blind alley. This paper describes a numerical solution to the stated problem, obtained with the modern DEIRA code developed for numerical modeling of inertially confined fusion. Detailed numerical calculations have confirmed the above 'historic' result and shed additional light on the physical causes of the detonation wave decay. The most pernicious factor is the radiation energy loss due to the combined effect of bremsstrahlung and the inverse Compton scattering of the emitted photons on the hot electrons. The impact of energy transfer by fast neutrons — which was already quite adequately accounted for in the above-cited historical work — is less significant. We present a more rigorous (compared to that of the 1950s) study of the role of inverse Compton scattering for which, in particular, an independent analytic estimate is obtained.

Thermonuclear Propaganda: Presentations of Nuclear Strategy in the Early Atomic Age

DTIC Science & Technology

2014-06-01

comics .17 One scholar of atomic culture noted the ambiguity of the duality of the atomic age as a central tenant to building the “most powerful of all...2004). 18 Ferenc Morton Szasz, Atomic Comics : Cartoonists Confront the Nuclear World (Reno, NV: University of Nevada Press, 2012), 135. 19 Ibid...research.archives.gov/description/36952. 28 Osgood, Total Cold War; Szasz, Atomic Comics ; Zeman and Amundson, Atomic Culture, 3-4. 10 the most modern

Health consequences and health systems response to the Pacific U.S. Nuclear Weapons Testing Program.

PubMed

Palafox, Neal A; Riklon, Sheldon; Alik, Wilfred; Hixon, Allen L

2007-03-01

Between 1946 and 1958, the United States detonated 67 thermonuclear devices in the Pacific as part of their U.S. Nuclear Weapons Testing Program (USNWTP). The aggregate explosive power was equal to 7,200 Hiroshima atomic bombs. Recent documents released by the U.S. government suggest that the deleterious effects of the nuclear testing were greater and extended farther than previously known. The Republic of the Marshall Islands (RMI) government and affected communities have sought refress through diplomatic routes with the U.S. government, however, existing medical programs and financial reparations have not adequately addressed many of the health consequences of the USNWTP. Since radiation-induced cancers may have a long latency, a healthcare infrastructure is needed to address both cancer and related health issues. This article reviews the health consequences of the Pacific USNWTP and the current health systems ability to respond.

α Heating in a Stagnated Z-pinch

NASA Astrophysics Data System (ADS)

Appelbe, Brian; Chittenden, Jeremy

2009-01-01

A computational investigation of a scheme for magneto-inertial confinement fusion in a Z-pinch is carried out. In the scheme implosion of a deuterium-tritium fuel mass is preceded by formation of a hotspot containing warm, dense plasma on axis. The presence of the hotspot increases energy yield. Compression of the hotspot by the main fuel mass initiates thermonuclear burn. There is significant heating of the plasma by thermonuclear α particles which are confined by the strong magnetic field of the Z-pinch.

The historical record for Sirius - Evidence for a white-dwarf thermonuclear runaway?

NASA Technical Reports Server (NTRS)

Bruhweiler, Frederick C.; Kondo, Yoji; Sion, Edward M.

1986-01-01

Evidence was recently presented that in medieval times Sirius was a bright red star, rather than the present bluish-white star. Here, the results of attempts to detect possible planetary nebula ejecta toward Sirius using data obtained by the IUE are presented. Based on these results and in the light of recent advances in understanding white-dwarf evolution, it is proposed that Sirius B underwent a recent thermonuclear runaway event triggered by a diffusion-induced CN reaction.

The Influence of Stellar Spin on Ignition of Thermonuclear Runaways

NASA Astrophysics Data System (ADS)

Galloway, Duncan K.; in ’t Zand, Jean J. M.; Chenevez, Jérôme; Keek, Laurens; Sanchez-Fernandez, Celia; Worpel, Hauke; Lampe, Nathanael; Kuulkers, Erik; Watts, Anna; Ootes, Laura; The MINBAR collaboration

2018-04-01

Runaway thermonuclear burning of a layer of accumulated fuel on the surface of a compact star provides a brief but intense display of stellar nuclear processes. For neutron stars accreting from a binary companion, these events manifest as thermonuclear (type-I) X-ray bursts, and recur on typical timescales of hours to days. We measured the burst rate as a function of accretion rate, from seven neutron stars with known spin rates, using a burst sample accumulated over several decades. At the highest accretion rates, the burst rate is lower for faster spinning stars. The observations imply that fast (>400 Hz) rotation encourages stabilization of nuclear burning, suggesting a dynamical dependence of nuclear ignition on the spin rate. This dependence is unexpected, because faster rotation entails less shear between the surrounding accretion disk and the star. Large-scale circulation in the fuel layer, leading to enhanced mixing of the burst ashes into the fuel layer, may explain this behavior; further numerical simulations are required to confirm this.

On the implementation of a chain nuclear reaction of thermonuclear fusion on the basis of the p+11B process

NASA Astrophysics Data System (ADS)

Belyaev, V. S.; Krainov, V. P.; Zagreev, B. V.; Matafonov, A. P.

2015-07-01

Various theoretical and experimental schemes for implementing a thermonuclear reactor on the basis of the p+11B reaction are considered. They include beam collisions, fusion in degenerate plasmas, ignition upon plasma acceleration by ponderomotive forces, and the irradiation of a solid-state target from 11B with a proton beam under conditions of a Coulomb explosion of hydrogen microdrops. The possibility of employing ultra-short high-intensity laser pulses to initiate the p+11B reaction under conditions far from thermodynamic equilibrium is discussed. This and some other weakly radioactive thermonuclear reactions are promising owing to their ecological cleanness—there are virtually no neutrons among fusion products. Nuclear reactions that follow the p+11B reaction may generate high-energy protons, sustaining a chain reaction, and this is an advantage of the p+11B option. The approach used also makes it possible to study nuclear reactions under conditions close to those in the early Universe or in the interior of stars.

Astrophysics at RIA (ARIA) Working Group

NASA Astrophysics Data System (ADS)

Smith, Michael S.; Schatz, Hendrik; Timmes, Frank X.; Wiescher, Michael; Greife, Uwe

2006-07-01

The Astrophysics at RIA (ARIA) Working Group has been established to develop and promote the nuclear astrophysics research anticipated at the Rare Isotope Accelerator (RIA). RIA is a proposed next-generation nuclear science facility in the U.S. that will enable significant progress in studies of core collapse supernovae, thermonuclear supernovae, X-ray bursts, novae, and other astrophysical sites. Many of the topics addressed by the Working Group are relevant for the RIKEN RI Beam Factory, the planned GSI-Fair facility, and other advanced radioactive beam facilities.

Computer Code Gives Astrophysicists First Full Simulation of Star's Final Hours

ScienceCinema

Andy Nonaka

2017-12-09

The precise conditions inside a white dwarf star in the hours leading up to its explosive end as a Type Ia supernova are one of the mysteries confronting astrophysicists studying these massive stellar explosions. But now, a team of researchers, composed of three applied mathematicians at the U.S. Department of Energy's (DOE) Lawrence Berkeley National Laboratory and two astrophysicists, has created the first full-star simulation of the hours preceding the largest thermonuclear explosions in the universe.

Nuclear-Physics Aspects of Controlled Thermonuclear Fusion: Analysis of Promising Fuels and Gamma-Ray Diagnostics of Hot Plasma

NASA Astrophysics Data System (ADS)

Voronchev, V. T.; Kukulin, V. I.

2000-12-01

A brief survey of nuclear-physics aspects of the problems of controlled thermonuclear fusion is given. Attention is paid primarily to choosing and analyzing an optimal composition of a nuclear fuel, reliably extrapolating the cross sections for nuclear reactions to the region of low energies, and exploring gamma-ray methods (as a matter of fact, very promising methods indeed) for diagnostics of hot plasmas (three aspects that are often thought to be the most important ones). In particular, a comparative nuclear-physics analysis of hydrogen, DT, and DD thermonuclear fuels and of their alternatives in the form of D3He, D6Li, DT6Li, H6Li, H11B, and H9Be is performed. Their advantages and disadvantages are highlighted; a spin-polarized fuel is considered; and the current status of nuclear data on the processes of interest is analyzed. A procedure for determining cross sections for nuclear reactions in the deep-subbarrier region is discussed. By considering the example of low-energy D+6Li interactions, it is shown that, at ion temperatures below 100 keV, the inclusion of nuclear-structure factors leads to an additional enhancement of the rate parameters <σv> for the ( d, pt) and ( d, nτ) channels by 10-40%. The possibility of using nuclear reactions that lead to photon emission as a means for determining the ion temperature of a thermonuclear plasma is discussed.

CONFERENCES AND SYMPOSIA: Commemoration of the centenary of the birth of Academician L A Artsimovich(Scientific session of the Physical Sciences Division of the Russian Academy of Sciences, 18 February 2009; Joint session of the Research Council of the Russian Research Centre 'Kurchatov Institute', the Presidium of the Russian Academy of Sciences, and the Rosatom State Corporation, 18 March 2009)

NASA Astrophysics Data System (ADS)

Khalatnikov, Isaak M.; Fortov, Vladimir E.; Makarov, Aleksandr A.; Fridman, Aleksei M.; Martynenko, Yurii V.

2009-12-01

The scientific session of the Physical Sciences Division of the Russian Academy of Sciences (RAS) devoted to the centenary of the birth of Academician L A Artsimovich was held on 18 February 2009 in the conference hall of the P N Lebedev Physical Institute, RAS. The following reports were presented at the session: (1) Khalatnikov I M (L D Landau Institute of Theoretical Physics, RAS, Chernogolovka, Moscow region) "Nonaccidental coincidences (Lev Andreevich Artsimovich)"; (2) Pashinin P P (A M Prokhorov Institute of General Physics, RAS, Moscow) "L A Artsimovich and inertial thermonuclear fusion"; (3) Fortov V E (Institute of Thermophysics of Extreme States of the Joint Institute for High Temperatures, RAS, Moscow) "High-power shock waves and extreme states of plasma"; (4) Fridman A M (Institute of Astronomy, RAS, Moscow) "Prediction and discovery of ultrastrong hydrodynamic instabilities caused by a velocity jump: theory and experiment"; (5) Smirnov V P (Russian Research Centre 'Kurchatov Institute', Moscow) "Retracing Artsimovich's path to the thermonuclear source of energy". On 18 March 2009, a joint session of the Learned Council of the Russian Research Centre 'Kurchatov Institute' (RNTsKI in Russ. abbr.), the Presidium of the Russian Academy of Sciences, and the Rosatom State Corporation took place at RNTsKI; the session was devoted to the 100th anniversary of the birth of Academician L A Artsimovich. The following talks were presented at the session: (1) Velikhov E P (Russian Research Centre 'Kurchatov Institute', Moscow) "Academician L A Artsimovich—the founder of our field of science and industry"; (2) Smirnov V P (Russian Research Centre 'Kurchatov Institute', Moscow) "Retracing Artsimovich's path to the thermonuclear source of energy"; (3) Boyarchuk A A (Division of General Physics and Astronomy, RAS, Moscow) "L A Artsimovich and astronomy"; (4) Martynenko Yu V (Institute of Nuclear Fusion, Russian Research Centre 'Kurchatov Institute', Moscow) "Electromagnetic isotope separation method and its heritage"; (5) Strelkov V S (Institute of Nuclear Fusion, Russian Research Centre 'Kurchatov Institute', Moscow) "Our teacher: Lev Andreevich Artsimovich"; (6) Mirnov S V (Institute of Nuclear Fusion, Russian Research Centre 'Kurchatov Institute', Moscow) "L A Artsimovich through the eyes of a former postgraduate student". • Nonaccidental coincidences (Lev Andreevich Artsimovich), I M Khalatnikov Physics-Uspekhi, 2009, Volume 52, Number 12, Pages 1248-1249 • Avenues for the innovative development of energetics in the world and in Russia, V E Fortov, A A Makarov Physics-Uspekhi, 2009, Volume 52, Number 12, Pages 1249-1265 • Lev Andreevich Artsimovich and extremely strong hydrodynamic instabilities, A M Fridman Physics-Uspekhi, 2009, Volume 52, Number 12, Pages 1265-1266 • Electromagnetic isotope separation method and its heritage, Yu V Martynenko Physics-Uspekhi, 2009, Volume 52, Number 12, Pages 1266-1272

Nuclear pursuits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1993-05-01

This table lists quantities of warheads (in stockpile, peak number per year, total number built, number of known test explosions), weapon development milestones (developers of the atomic bomb and hydrogen bomb, date of first operational ICBM, first nuclear-powered naval SSN in service, first MIRVed missile deployed), and testing milestones (first fission test, type of boosted fission weapon, multistage thermonuclear test, number of months from fission bomb to multistage thermonuclear bomb, etc.), and nuclear infrastructure (assembly plants, plutonium production reactors, uranium enrichment plants, etc.). Countries included in the tally are the United States, Soviet Union, Britain, France, and China.

Fusion Safety Program annual report, fiscal year 1994

NASA Astrophysics Data System (ADS)

Longhurst, Glen R.; Cadwallader, Lee C.; Dolan, Thomas J.; Herring, J. Stephen; McCarthy, Kathryn A.; Merrill, Brad J.; Motloch, Chester C.; Petti, David A.

1995-03-01

This report summarizes the major activities of the Fusion Safety Program in fiscal year 1994. The Idaho National Engineering Laboratory (INEL) is the designated lead laboratory and Lockheed Idaho Technologies Company is the prime contractor for this program. The Fusion Safety Program was initiated in 1979. Activities are conducted at the INEL, at other DOE laboratories, and at other institutions, including the University of Wisconsin. The technical areas covered in this report include tritium safety, beryllium safety, chemical reactions and activation product release, safety aspects of fusion magnet systems, plasma disruptions, risk assessment failure rate data base development, and thermalhydraulics code development and their application to fusion safety issues. Much of this work has been done in support of the International Thermonuclear Experimental Reactor (ITER). Also included in the report are summaries of the safety and environmental studies performed by the Fusion Safety Program for the Tokamak Physics Experiment and the Tokamak Fusion Test Reactor and of the technical support for commercial fusion facility conceptual design studies. A major activity this year has been work to develop a DOE Technical Standard for the safety of fusion test facilities.

30S(α , p) Thermonuclear Reaction Rate from Experimental Level Structure of 34Ar

NASA Astrophysics Data System (ADS)

Kahl, D.; Chen, A. A.; Kubono, S.; Yamaguchi, H.; Binh, D. N.; Chen, J.; Cherubini, S.; Duy, N. N.; Hashimoto, T.; Hayakawa, S.; Iwasa, N.; Jung, H. S.; Kato, S.; Kwon, Y. K.; Nishimura, S.; Ota, S.; Setoodehnia, K.; Teranishi, T.; Tokieda, H.; Yamada, T.; Yun, C. C.; Zhang, L. Y.

Type I X-ray bursts are the most frequent thermonuclear explosions in the galaxy. Owing to their recurrence from known astronomical objects, burst morphology is extensively documented, and they are modeled very successfully as neutron-deficient, thermonuclear runaway on the surface of accreting neutron stars. While reaction networks include hundreds of isotopes and thousands of nuclear processes, only a small subset appear to play a pivotal role. One such reaction is the 30S(α , p) reaction, which is believed to be a crucial link in the explosive helium burning which is responsible for the large energy flux. However, very little experimental information is available concerning the cross section itself, nor the 34Ar compound nucleus at the relevant energies. We performed the first study of the entrance channel via 30S alpha resonant elastic scattering using a state-of-the-art, low-energy, 30S radioactive ion beam. The measurement was performed in inverse kinematics using a newly-developed active target. An R-matrix analysis of the excitation function reveals previously unknown resonances, including their quantum properties of spin, parity, width, and energy.

On the implementation of a chain nuclear reaction of thermonuclear fusion on the basis of the p+{sup 11}B process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Belyaev, V. S.; Krainov, V. P., E-mail: vpkrainov@mail.ru; Zagreev, B. V.

2015-07-15

Various theoretical and experimental schemes for implementing a thermonuclear reactor on the basis of the p+{sup 11}B reaction are considered. They include beam collisions, fusion in degenerate plasmas, ignition upon plasma acceleration by ponderomotive forces, and the irradiation of a solid-state target from {sup 11}B with a proton beam under conditions of a Coulomb explosion of hydrogen microdrops. The possibility of employing ultra-short high-intensity laser pulses to initiate the p+{sup 11}B reaction under conditions far from thermodynamic equilibrium is discussed. This and some other weakly radioactive thermonuclear reactions are promising owing to their ecological cleanness—there are virtually no neutrons amongmore » fusion products. Nuclear reactions that follow the p+{sup 11}B reaction may generate high-energy protons, sustaining a chain reaction, and this is an advantage of the p+{sup 11}B option. The approach used also makes it possible to study nuclear reactions under conditions close to those in the early Universe or in the interior of stars.« less

Thermonuclear reactions probed at stellar-core conditions with laser-based inertial-confinement fusion

DOE PAGES

Casey, D. T.; Sayre, D. B.; Brune, C. R.; ...

2017-08-07

Stars are giant thermonuclear plasma furnaces that slowly fuse the lighter elements in the universe into heavier elements, releasing energy, and generating the pressure required to prevent collapse. To understand stars, we must rely on nuclear reaction rate data obtained, up to now, under conditions very different from those of stellar cores. Here we show thermonuclear measurements of the 2H(d, n) 3He and 3H(t,2n) 4He S-factors at a range of densities (1.2–16 g cm –3) and temperatures (2.1–5.4 keV) that allow us to test the conditions of the hydrogen-burning phase of main-sequence stars. The relevant conditions are created using inertial-confinementmore » fusion implosions at the National Ignition Facility. Here, our data agree within uncertainty with previous accelerator-based measurements and establish this approach for future experiments to measure other reactions and to test plasma-nuclear effects present in stellar interiors, such as plasma electron screening, directly in the environments where they occur.« less

Results from the MARBLE Campaign on the National Ignition Facility: Implosion of Foam-Filled Capsules for Studying Thermonuclear Burn in the Presence of Heterogeneous Mix

NASA Astrophysics Data System (ADS)

Murphy, T. J.; Douglas, M. R.; Cardenas, T.; Devolder, B. G.; Fincke, J. R.; Gunderson, M. A.; Haines, B. M.; Hamilton, C. E.; Kim, Y. H.; Lee, M. N.; Oertel, J. A.; Olson, R. E.; Randolph, R. B.; Shah, R. C.; Smidt, J. M.

2016-10-01

The MARBLE campaign on NIF investigates the effect of heterogeneous mix on thermonuclear burn for comparison to a probability distribution function (PDF) burn model. MARBLE utilizes plastic capsules filled with deuterated plastic foam and tritium gas. The ratio of DT to DD neutron yield is indicative of the degree to which the foam and the gas atomically mix. Platform development experiments have been performed to understand the behavior of the foam and of the gas separately using two types of capsule. The first uses partially deuterated foam and hydrogen gas fill to understand the burn in the foam. The second uses undeuterated foam and deuterium gas fill to understand the dynamics of the gas. Experiments using deuterated foam and tritium gas are planned. Results of these experiments, and the implications for our understanding of thermonuclear burn in heterogeneously mixed separated reactant experiments will be discussed. This work is supported by US DOE/NNSA, performed at LANL, operated by LANS LLC under contract DE-AC52-06NA25396.

The LOFT perspective on neutron star thermonuclear bursts: White paper in support of the mission concept of the large observatory for X-ray timing

DOE Office of Scientific and Technical Information (OSTI.GOV)

in't Zand, J. J.M.; Malone, Christopher M.; Altamirano, D.

2015-01-14

The Large Area Detector (LAD) on the Large Observatory For X-ray Timing ( LOFT ), with a 8.5 m 2 photon- collecting area in the 2–30 keV bandpass at CCD-class spectral resolving power (λ/Δλ = 10 – 100), is designed for optimum performance on bright X-ray sources. Thus, it is well-suited to study thermonuclear X-ray bursts from Galactic neutron stars. These bursts will typically yield 2 x 10 5 photon detections per second in the LAD, which is at least 15 times more than with any other instrument past, current or anticipated. The Wide Field Monitor (WFM) foreseen for LOFTmore » uniquely combines 2–50 keV imaging with large (30%) prompt sky coverage. This will enable the detection of tens of thousands of thermonuclear X-ray bursts during a 3-yr mission, including tens of superbursts. Both numbers are similar or more than the current database gathered in 50 years of X-ray astronomy.« less

Studies of high-current relativistic electron beam interaction with gas and plasma in Novosibirsk

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sinitsky, S. L., E-mail: s.l.sinitsky@inp.nsk.su; Arzhannikov, A. V.; Novosibirsk State University, 2 Pirogova St., Novosibirsk, 630090

2016-03-25

This paper presents an overview of the studies on the interaction of a high-power relativistic electron beam (REB) with dense plasma confined in a long open magnetic trap. The main goal of this research is to achieve plasma parameters close to those required for thermonuclear fusion burning. The experimental studies were carried over the course of four decades on various devices: INAR, GOL, INAR-2, GOL-M, and GOL-3 (Budker Institute of Nuclear Physics) for a wide range of beam and plasma parameters.

Computer Code Gives Astrophysicists First Full Simulation of Star's Final Hours

ScienceCinema

Applin, Bradford; Almgren, Ann S.; Nonaka, Andy

2018-05-11

The precise conditions inside a white dwarf star in the hours leading up to its explosive end as a Type Ia supernova are one of the mysteries confronting astrophysicists studying these massive stellar explosions. But now, a team of researchers, composed of three applied mathematicians at the U.S. Department of Energy's (DOE) Lawrence Berkeley National Laboratory and two astrophysicists, has created the first full-star simulation of the hours preceding the largest thermonuclear explosions in the universe. http://www.lbl.gov/cs/Archive/news091509.html

Thermonuclear runaways in thick hydrogen rich envelopes of neutron stars

NASA Technical Reports Server (NTRS)

Starrfield, S. G.; Kenyon, S.; Truran, J. W.; Sparks, W. M.

1981-01-01

A Lagrangian, fully implicit, one dimensional hydrodynamic computer code was used to evolve thermonuclear runaways in the accreted hydrogen rich envelopes of 1.0 Msub solar neutron stars with radii of 10 km and 20 km. Simulations produce outbursts which last from about 750 seconds to about one week. Peak effective temeratures and luninosities were 26 million K and 80 thousand Lsub solar for the 10 km study and 5.3 millison and 600 Lsub solar for the 20 km study. Hydrodynamic expansion on the 10 km neutron star produced a precursor lasting about one ten thousandth seconds.

Burst Oscillations: A New Spin on Neutron Stars

NASA Technical Reports Server (NTRS)

Strohmayer, Tod

2007-01-01

Observations with NASA's Rossi X-ray Timing Explorer (RXTE) have shown that the X-ray flux during thermonuclear X-ray bursts fr-om accreting neutron stars is often strongly pulsed at frequencies as high as 620 Hz. We now know that these oscillations are produced by spin modulation of the thermonuclear flux from the neutron star surface. In addition to revealing the spin frequency, they provide new ways to probe the properties and physics of accreting neutron stars. I will briefly review our current observational and theoretical understanding of these oscillations and discuss what they are telling us about neutron stars.

Review of controlled fusion research using laser heating.

NASA Technical Reports Server (NTRS)

Hertzberg, A.

1973-01-01

Development of methods for generating high laser pulse energy has stimulated research leading to new ideas for practical controlled thermonuclear fusion machines. A review is presented of some important efforts in progress, and two different approaches have been selected as examples for discussion. One involves the concept of very short pulse lasers with power output tailored, in time, to obtain a nearly isentropic compression of a deuterium-tritium pellet to very high densities and temperatures. A second approach utilizing long wavelength, long pulse, efficient gas lasers to heat a column of plasma contained in a solenoidal field is also discussed. The working requirements of the laser and various magnetic field geometries of this approach are described.

Fusion plasma theory project summaries

NASA Astrophysics Data System (ADS)

1993-10-01

This Project Summary book is a published compilation consisting of short descriptions of each project supported by the Fusion Plasma Theory and Computing Group of the Advanced Physics and Technology Division of the Department of Energy, Office of Fusion Energy. The summaries contained in this volume were written by the individual contractors with minimal editing by the Office of Fusion Energy. Previous summaries were published in February of 1982 and December of 1987. The Plasma Theory program is responsible for the development of concepts and models that describe and predict the behavior of a magnetically confined plasma. Emphasis is given to the modelling and understanding of the processes controlling transport of energy and particles in a toroidal plasma and supporting the design of the International Thermonuclear Experimental Reactor (ITER). A tokamak transport initiative was begun in 1989 to improve understanding of how energy and particles are lost from the plasma by mechanisms that transport them across field lines. The Plasma Theory program has actively participated in this initiative. Recently, increased attention has been given to issues of importance to the proposed Tokamak Physics Experiment (TPX). Particular attention has been paid to containment and thermalization of fast alpha particles produced in a burning fusion plasma as well as control of sawteeth, current drive, impurity control, and design of improved auxiliary heating. In addition, general models of plasma behavior are developed from physics features common to different confinement geometries. This work uses both analytical and numerical techniques. The Fusion Theory program supports research projects at U.S. government laboratories, universities and industrial contractors. Its support of theoretical work at universities contributes to the office of Fusion Energy mission of training scientific manpower for the U.S. Fusion Energy Program.

High-Speed Turbulent Reacting Flows: Intrinsic Flame Instability and its Effects on the Turbulent Cascade

NASA Astrophysics Data System (ADS)

Poludnenko, Alexei

2016-11-01

Turbulent reacting flows are pervasive both in our daily lives on Earth and in the Universe. They power modern society being at the heart of many energy generation and propulsion systems, such as gas turbines, internal combustion and jet engines. On astronomical scales, thermonuclear turbulent flames are the driver of some of the most powerful explosions in the Universe, knows as Type Ia supernovae. Despite this ubiquity in Nature, turbulent reacting flows still pose a number of fundamental questions often exhibiting surprising and unexpected behavior. In this talk, we will discuss several such phenomena observed in direct numerical simulations of high-speed, premixed, turbulent flames. We show that turbulent flames in certain regimes are intrinsically unstable even in the absence of the surrounding combustor walls or obstacles, which can support the thermoacoustic feedback. Such instability can fundamentally change the structure and dynamics of the turbulent cascade, resulting in a significant (and anisotropic) redistribution of kinetic energy from small to large scales. In particular, three effects are observed. 1) The turbulent burning velocity can develop pulsations with significant peak-to-peak amplitudes. 2) Unstable burning can result in pressure build-up and the formation of pressure waves or shocks when the flame speed approaches or exceeds the speed of a Chapman-Jouguet deflagration. 3) Coupling of pressure and density gradients across the flame can lead to the anisotropic generation of turbulence inside the flame volume and flame acceleration. We extend our earlier analysis, which relied on a simplified single-step reaction model, by demonstrating existence of these effects in realistic chemical flames (hydrogen and methane) and in thermonuclear flames in degenerate, relativistic plasmas found in stellar interiors. Finally, we discuss the implications of these results for subgrid-scale LES combustion models. This work was supported by the Air Force Office of Scientific Research (AFOSR) under Award No. F4FGA06055G001, and the Department of Defense (DoD) High Performance Computing Modernization Program (HPCMP) under a Frontier project award.

The secret of the Soviet hydrogen bomb

NASA Astrophysics Data System (ADS)

Wellerstein, Alex; Geist, Edward

2017-11-01

Was the first Soviet thermonuclear device really a step in the wrong direction? No bomb design has been as much maligned or otherwise disparaged as the first Soviet thermonuclear weapon. Detonated in August 1953, the bomb, officially tested under the name RDS-6s but usually known as Sloika or "layer cake" (the name Andrei Sakharov coined for it), was nothing to sneeze at. Shown in Figure 1 and able to be dropped from aircraft, it released the explosive equivalent, or yield, of almost half a megaton of TNT. The result was a blazing fireball with 20 times the power of the bomb that leveled Nagasaki, Japan.

Extended fusion yield integral using pathway idea in case of Shock-compressed heated plasma

NASA Astrophysics Data System (ADS)

Kumar, Dilip; Haubold, Hans

The extended non-resonant thermonuclear reaction rate probability integral obtained in Haubold and Kumar [Haubold, H.J. and Kumar, D.: 2008, Extension of thermonuclear functions through the pathway model including Maxwell-Boltzmann and Tsallis distributions, Astroparticle Physics, 29, 70-76] is used to evaluate the fusion energy by itegrating it over temperature. The closed form representation of the extended reaction rate integral via Meijer's G-function is expressed as a solution of a homogeneous differential equation. A physical model of Guderley[Guderley G. :1942, Starke kugelige und zylindrische Verdichtungsstsse in der Nhe des Kugelmittelpunktes bzw. der Zylinderachse, Luftfahrtforschung, 19, 302] has been considered for the laser driven hydrodynamical process in a compressed fusion plasma and heated strong spherical shock wave. The fusion yield integral obtained in the paper is compared with the standard fusion yield ob-tained by Haubold and John [Haubold, H.J. and John, R.W.:1981, Analytical representation of the thermonuclear reaction rate and fusion energy production in a spherical plasma shock wave, Plasma Physics, 5, 399-411]. The pathway parameter used in this paper is given an interpretation in terms of moments.

The classification of magnetohydrodynamic regimes of thermonuclear combustion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Remming, Ian S.; Khokhlov, Alexei M.

2014-10-10

Physical properties of magnetohydrodynamic (MHD) reaction fronts are studied as functions of the thermodynamic conditions, and the strength and orientation of the magnetic field in the unburned matter through which the fronts propagate. We determine the conditions for the existence of the various types of MHD reaction fronts and the character of the changes in physical quantities across these reaction fronts. The analysis is carried out in general for a perfect gas equation of state and a constant energy release, and then extended to thermonuclear reaction fronts in degenerate carbon-oxygen mixtures and degenerate helium in conditions typical of Type Iamore » supernova explosions. We find that as unburned matter enters perpendicular to a reaction front, the release of energy through burning generates shear velocity in the reacting gas that, depending on the type of reaction front, strengthens or weakens the magnetic field. In addition, we find that the steady-state propagation of a reaction front is impossible for certain ranges of magnetic field direction. Our results provide insight into the phenomena of MHD thermonuclear combustion that is relevant to the interpretation of future simulations of SN Ia explosions that have magnetic fields systematically incorporated.« less

Thermonuclear Explosions from Hybrid C/O/Ne White Dwarf Progenitors Ignited Centrally After Interior Mixing

NASA Astrophysics Data System (ADS)

Augustine, Carlyn

2018-01-01

Type Ia Supernovae are thermonuclear explosions of white dwarf (WD) stars. Past studies predict the existence of "hybrid" white dwarfs, made of a C/O/Ne core with a O/Ne shell, and that these are viable progenitors for supernovae. More recent work found that the C/O core is mixed with the surrounding O/Ne while the WD cools. Inspired by this scenario, we performed simulations of thermonuclear supernovae in the single degenerate paradigm from these hybrid progenitors. Our investigation began by constructing a hybrid white dwarf model with the one-dimensional stellar evolution code MESA. The model was allowed to go through unstable interior mixing ignite carbon burning centrally. The MESA model was then mapped to a two-dimensional initial condition and an explosion simulated from that with FLASH. For comparison, a similar simulation of an explosion was performed from a traditional C/O progenitor WD. Comparing the yields produced by explosion simulations allows us to determine which model produces more 56Ni, and therefore brighter events, and how explosions from these models differ from explosions from previous models without the mixing during the WD cooling.

Sandia technology: Engineering and science applications

NASA Astrophysics Data System (ADS)

Maydew, M. C.; Parrot, H.; Dale, B. C.; Floyd, H. L.; Leonard, J. A.; Parrot, L.

1990-12-01

This report discusses: protecting environment, safety, and health; Sandia's quality initiative; Sandia vigorously pursues technology transfer; scientific and technical education support programs; nuclear weapons development; recognizing battlefield targets with trained artificial neural networks; battlefield robotics: warfare at a distance; a spinning shell sizes up the enemy; thwarting would-be nuclear terrorists; unattended video surveillance system for nuclear facilities; making the skies safer for travelers; onboard instrumentation system to evaluate performance of stockpile bombs; keeping track with lasers; extended-life lithium batteries; a remote digital video link acquires images securely; guiding high-performance missiles with laser gyroscopes; nonvolatile memory chips for space applications; initiating weapon explosives with lasers; next-generation optoelectronics and microelectronics technology developments; chemometrics: new methods for improving chemical analysis; research team focuses ion beam to record-breaking intensities; standardizing the volt to quantum accuracy; new techniques improve robotic software development productivity; a practical laser plasma source for generating soft x-rays; exploring metal grain boundaries; massively parallel computing; modeling the amount of desiccant needed for moisture control; attacking pollution with sunshine; designing fuel-conversion catalysts with computers; extending a nuclear power plant's useful life; plasma-facing components for the International Thermonuclear Experimental Reactor.

Nuclear transmutation in steels

NASA Astrophysics Data System (ADS)

Belozerova, A. R.; Shimanskii, G. A.; Belozerov, S. V.

2009-05-01

The investigations of the effects of nuclear transmutation in steels that are widely used in nuclear power and research reactors and in steels that are planned for the application in thermonuclear fusion plants, which are employed under the conditions of a prolonged action of neutron irradiation with different spectra, made it possible to study the effects of changes in the isotopic and chemical composition on the tendency of changes in the structural stability of these steels. For the computations of nuclear transmutation in steels, we used a program complex we have previously developed on the basis of algorithms for constructing branched block-type diagrams of nuclide transformations and for locally and globally optimizing these diagrams with the purpose of minimizing systematic errors in the calculation of nuclear transmutation. The dependences obtained were applied onto a Schaeffler diagram for steels used for structural elements of reactors. For the irradiation in fission reactors, we observed only a weak influence of the effects of nuclear transmutation in steels on their structural stability. On the contrary, in the case of irradiation with fusion neutrons, a strong influence of the effects of nuclear transmutation in steels on their structural stability has been noted.

Future space transport

NASA Technical Reports Server (NTRS)

Grishin, S. D.; Chekalin, S. V.

1984-01-01

Prospects for the mastery of space and the basic problems which must be solved in developing systems for both manned and cargo spacecraft are examined. The achievements and flaws of rocket boosters are discussed as well as the use of reusable spacecraft. The need for orbiting satellite solar power plants and related astrionics for active control of large space structures for space stations and colonies in an age of space industrialization is demonstrated. Various forms of spacecraft propulsion are described including liquid propellant rocket engines, nuclear reactors, thermonuclear rocket engines, electrorocket engines, electromagnetic engines, magnetic gas dynamic generators, electromagnetic mass accelerators (rail guns), laser rocket engines, pulse nuclear rocket engines, ramjet thermonuclear rocket engines, and photon rockets. The possibilities of interstellar flight are assessed.

Laser-fusion targets for reactors

DOEpatents

Nuckolls, John H.; Thiessen, Albert R.

1987-01-01

A laser target comprising a thermonuclear fuel capsule composed of a centrally located quantity of fuel surrounded by at least one or more layers or shells of material for forming an atmosphere around the capsule by a low energy laser prepulse. The fuel may be formed as a solid core or hollow shell, and, under certain applications, a pusher-layer or shell is located intermediate the fuel and the atmosphere forming material. The fuel is ignited by symmetrical implosion via energy produced by a laser, or other energy sources such as an electron beam machine or ion beam machine, whereby thermonuclear burn of the fuel capsule creates energy for applications such as generation of electricity via a laser fusion reactor.

Shock ignition: a new approach to high gain inertial confinement fusion on the national ignition facility.

PubMed

Perkins, L J; Betti, R; LaFortune, K N; Williams, W H

2009-07-24

Shock ignition, an alternative concept for igniting thermonuclear fuel, is explored as a new approach to high gain, inertial confinement fusion targets for the National Ignition Facility (NIF). Results indicate thermonuclear yields of approximately 120-250 MJ may be possible with laser drive energies of 1-1.6 MJ, while gains of approximately 50 may still be achievable at only approximately 0.2 MJ drive energy. The scaling of NIF energy gain with laser energy is found to be G approximately 126E (MJ);{0.510}. This offers the potential for high-gain targets that may lead to smaller, more economic fusion power reactors and a cheaper fusion energy development path.

Carbon 14 measurements in surface water CO{sub 2} from the Atlantic, India, and Pacific Oceans, 1965--1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nydal, R.; Brenkert, A.L.; Boden, T.A.

1998-03-01

In the 1960s, thermonuclear bomb tests released significant pulses of radioactive carbon-14 ({sup 14}C) into the atmosphere. These major perturbations allowed scientists to study the dynamics of the global carbon cycle by calculating rates of isotope exchange between the atmosphere and ocean waters. A total of 950 ocean surface water observations were made from 1965 through 1994. The measurements were taken at 30 stations in the Atlantic Ocean, 14 stations in the Indian Ocean, and 38 stations in the Pacific Ocean. Thirty-two of the 950 samples were taken in the Atlantic Ocean during the R/V Andenes research cruise. {sup 14}Cmore » was measured in 871 of the 950 samples, and those measurements have been corrected ({Delta}{sup 14}C) for isotopic fractionation and radioactive decay. The {Delta}{sup 14}C values range between {minus}113.3 and 280.9 per mille and have a mean value of 101.3 per mille. The highest yearly mean (146.5 per mille) was calculated for 1969, the lowest yearly mean value was calculated for 1990 (67.9 per mille) illustrating a decrease over time. This decrease was to be expected as a result of the ban on atmospheric thermonuclear tests and the slow mixing of the ocean surface waters with the deeper layers.« less

Thermal modeling of W rod armor.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nygren, Richard Einar

2004-09-01

Sandia has developed and tested mockups armored with W rods over the last decade and pioneered the initial development of W rod armor for International Thermonuclear Experimental Reactor (ITER) in the 1990's. We have also developed 2D and 3D thermal and stress models of W rod-armored plasma facing components (PFCs) and test mockups and are applying the models to both short pulses, i.e. edge localized modes (ELMs), and thermal performance in steady state for applications in C-MOD, DiMES testing and ITER. This paper briefly describes the 2D and 3D models and their applications with emphasis on modeling for an ongoingmore » test program that simulates repeated heat loads from ITER ELMs.« less

Final Report on ITER Task Agreement 81-10

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brad J. Merrill

An International Thermonuclear Experimental Reactor (ITER) Implementing Task Agreement (ITA) on Magnet Safety was established between the ITER International Organization (IO) and the Idaho National Laboratory (INL) Fusion Safety Program (FSP) during calendar year 2004. The objectives of this ITA were to add new capabilities to the MAGARC code and to use this updated version of MAGARC to analyze unmitigated superconductor quench events for both poloidal field (PF) and toroidal field (TF) coils of the ITER design. This report documents the completion of the work scope for this ITA. Based on the results obtained for this ITA, an unmitigated quenchmore » event in an ITER larger PF coil does not appear to be as severe an accident as in an ITER TF coil.« less

Effects of Thermonuclear X-Ray Bursts on Non-burst Emissions in the Soft State of 4U 1728–34

NASA Astrophysics Data System (ADS)

Bhattacharyya, Sudip; Yadav, J. S.; Sridhar, Navin; Verdhan Chauhan, Jai; Agrawal, P. C.; Antia, H. M.; Pahari, Mayukh; Misra, Ranjeev; Katoch, Tilak; Manchanda, R. K.; Paul, Biswajit

2018-06-01

It has recently been shown that the persistent emission of a neutron star low-mass X-ray binary (LMXB) evolves during a thermonuclear (type-I) X-ray burst. The reason of this evolution, however, is not fully known. This uncertainty can introduce significant systematics in the neutron star radius measurement using burst spectra, particularly if an unknown but significant fraction of the burst emission, which is reprocessed, contributes to the changes in the persistent emission during the burst. Here, by analyzing individual burst data of AstroSat/LAXPC from the neutron star LMXB 4U 1728–34 in the soft state, we show that the burst emission is not significantly reprocessed by a corona covering the neutron star. Rather, our analysis suggests that the burst emission enhances the accretion disk emission, possibly by increasing the accretion rate via disk. This enhanced disk emission, which is Comptonized by a corona covering the disk, can explain an increased persistent emission observed during the burst. This finding provides an understanding of persistent emission components and their interaction with the thermonuclear burst emission. Furthermore, as burst photons are not significantly reprocessed, non-burst and burst emissions can be reliably separated, which is required to reduce systematic uncertainties in the stellar radius measurement.

Oscillations During Thermonuclear X-ray Bursts

NASA Technical Reports Server (NTRS)

Strohmayer, Tod E.; White, Nicholas E. (Technical Monitor)

2001-01-01

High amplitude, nearly coherent X-ray brightness oscillations during thermonuclear X-ray bursts were discovered with the Rossi X-ray Timing Explorer (RXTE) in early 1996. Spectral and timing evidence strongly supports the conclusion that these oscillations are caused by rotational modulation of the burst emission and that they reveal the spin frequency of neutron stars in low mass X-ray binaries, a long sought goal of X-ray astronomy. Studies carried out over the past year have led to the discovery of burst oscillations in four new sources, bringing to ten the number with confirmed burst oscillations. I review the status of our knowledge of these oscillations and indicate how they can be used to probe the physics of neutron stars. For a few burst oscillation sources it has been proposed that the strongest and most ubiquitous frequency is actually the first overtone of the spin frequency and hence that two nearly antipodal hot spots are present on the neutron star. This inference has important implications for both the physics of thermonuclear burning as well as the mass - radius relation for neutron stars, so its confirmation is crucial. I discuss recent attempts to confirm this hypothesis for 4U 1636-53, the source for which a signal at the putative fundamental (290Hz) has, been claimed.

Search for stellar collapse with the MACRO detector at Gran Sasso

NASA Technical Reports Server (NTRS)

Steinberg, R.

1985-01-01

It is viewed that in stellar evolution stars in the range of 8 to 12 solar masses evolve gradually as increasingly heavier nuclei are produced and then consumed in a series of exothermic thermonuclear processes ultimately leading to the formation of a core composed almost entirely of nickel and iron. When the mass of this hot iron-nickel core reaches the critical value of approximately 1.4 solar masses, electron degeneracy pressure is no longer able to support the outer layers of the star and a collapse process begins. Since the core has exhausted its thermonuclear fuel, further stages of thermonuclear burning cannot prevent a runaway collapse. As the density reaches 10 to the 10th power gm sub/cm at a temperature near 10 to the 10th power k, most of the heavy nuclei are dissociated into free nucleons and electron capture on free protons leads to a decrease in the degeneracy pressure and further acceleration of the collapse process. Although this general picture has received substantial confirmation over the past two decades with the discovery of radio pulsars (neutron stars), X-ray pulsars (accreting binary neutron stars) and Cyg X-1 (probably an accreting black hole), an actual neutrino burst is not yet convincingly detected.

Stabilization of burn conditions in a thermonuclear reactor using artificial neural networks

NASA Astrophysics Data System (ADS)

Vitela, Javier E.; Martinell, Julio J.

1998-02-01

In this work we develop an artificial neural network (ANN) for the feedback stabilization of a thermonuclear reactor at nearly ignited burn conditions. A volume-averaged zero-dimensional nonlinear model is used to represent the time evolution of the electron density, the relative density of alpha particles and the temperature of the plasma, where a particular scaling law for the energy confinement time previously used by other authors, was adopted. The control actions include the concurrent modulation of the D-T refuelling rate, the injection of a neutral He-4 beam and an auxiliary heating power modulation, which are constrained to take values within a maximum and minimum levels. For this purpose a feedforward multilayer artificial neural network with sigmoidal activation function is trained using a back-propagation through-time technique. Numerical examples are used to illustrate the behaviour of the resulting ANN-dynamical system configuration. It is concluded that the resulting ANN can successfully stabilize the nonlinear model of the thermonuclear reactor at nearly ignited conditions for temperature and density departures significantly far from their nominal operating values. The NN-dynamical system configuration is shown to be robust with respect to the thermalization time of the alpha particles for perturbations within the region used to train the NN.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vaswani, A.N.; Howard, J.E.

This is the 17th and final report of the Marshall Islands Medical Program as carried out by the Brookhaven National Laboratory (BNL). The purpose of these publications has been to provide information on the medical status of 253 Marshallese exposed to radiation fallout in 1954. The medical program fulfills a commitment to disclose unique medical information relevant to public health. Details of the Bravo thermonuclear accident that caused the exposure have been published. A 1955 article in the Journal of the American Medical Association, which described the acute medical effects on the population that required special medical care, remains amore » definitive and relevant description of events. Marshallese participation in this Congressionally mandated program is voluntary. Throughout the 44 years of the program, each participating individual`s relevant medical findings, laboratory data, disease morbidity, and mortality have been published in the BNL reports in a manner preserving patient confidentiality. In each report, there has been an attempt to interpret these findings and to infer the role of radiation exposure in their development. An equally important aspect of the reports has been the presentation of data that allows for analyses of the medical consequences of the Marshallese exposure.« less

Present status of MHD research and development in Israel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Branover, H.; Lesin, S.

1994-12-31

As in the previous years the Israel MHD program is concentrating exclusively on Liquid Metal MHD (LMMHD). The main effort is the development of gravitational heavy metal power generation systems with a Faraday type generator (ETGAR-type system). However, in the wake of this main development a number of diverse research projects are also elaborated. Two of those projects are reflected in this paper. First is the direct contact boiling of volatile thermodynamic liquids in hot liquid metals and the second is MHD turbulence with a variety of applications. The LMMHD power generation project is now about to enter the stagemore » of building a semi-commercial scale demonstration plant. The concept and performance parameters of this plant have been presented already at SEAM 30. Direct contact boiling of the volatile liquid in a hot metal leads to a substantial decrease of the cost of a LMMHD power generation system. Indeed, in this case a separate boiler is not needed. Moreover, the overall efficiency of the system is increased through achieving a more desirable two-phase flow pattern. A Special integrated facility for this study is in advanced stage of assembly and it will be put in operation soon. It will work with lead and water at temperatures up to 750{degrees}K. In the field of MHD Turbulence research, studies of two applications are pursued. The first is related to the engineering of liquid metal blankets in thermonuclear reactors. The second is connected with a possibility to simulate large scale atmospheric and oceanic turbulence using a laboratory MHD channel with liquid metal flow.« less

Laser induced sonofusion: A new road toward thermonuclear reactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sadighi-Bonabi, Rasoul, E-mail: Sadighi@sharif.ir; Gheshlaghi, Maryam; Laser and optics research school, Nuclear Science and Technology Research Institute

2016-03-15

The Possibility of the laser assisted sonofusion is studied via single bubble sonoluminescence (SBSL) in Deuterated acetone (C{sub 3}D{sub 6}O) using quasi-adiabatic and hydro-chemical simulations at the ambient temperatures of 0 and −28.5 °C. The interior temperature of the produced bubbles in Deuterated acetone is 1.6 × 10{sup 6} K in hydro-chemical model and it is reached up to 1.9 × 10{sup 6} K in the laser induced SBSL bubbles. Under these circumstances, temperature up to 10{sup 7} K can be produced in the center of the bubble in which the thermonuclear D-D fusion reactions are promising under the controlled conditions.

Evidence for a link between atmospheric thermonuclear detonations and nitric acid.

PubMed

Holdsworth, G

1986-12-11

Suitably located glacier cores, obtained from high-altitude, low-temperature sites, can reveal detailed information about atmospheric air chemistry at sub-annual resolution 1 . Such data may provide input to climate-change models, the study of acid precipitation patterns and many other phenomena. Here I present data from an ice core which show that during the era of intense atmospheric thermonuclear weapons testing (ATWT) a significant part of the nitrate content in the snow was modulated by the intensity of the nuclear detonations. The fixation of nitrogen by nuclear fireballs leads to NO x gases in the atmosphere 2 and ultimately to nitric acid in precipitation. At certain concentrations, these gases and the associated aerosols may perturb the climate 3,4 .

NACRE II: an update of the NACRE compilation of charged-particle-induced thermonuclear reaction rates for nuclei with mass number A<16

NASA Astrophysics Data System (ADS)

Xu, Y.; Takahashi, K.; Goriely, S.; Arnould, M.; Ohta, M.; Utsunomiya, H.

2013-11-01

An update of the NACRE compilation [3] is presented. This new compilation, referred to as NACRE II, reports thermonuclear reaction rates for 34 charged-particle induced, two-body exoergic reactions on nuclides with mass number A<16, of which fifteen are particle-transfer reactions and the rest radiative capture reactions. When compared with NACRE, NACRE II features in particular (1) the addition to the experimental data collected in NACRE of those reported later, preferentially in the major journals of the field by early 2013, and (2) the adoption of potential models as the primary tool for extrapolation to very low energies of astrophysical S-factors, with a systematic evaluation of uncertainties.

A NON-PRE DOUBLE-PEAKED BURST FROM 4U 1636-536: EVIDENCE FOR BURNING FRONT PROPAGATION

NASA Technical Reports Server (NTRS)

Bhattacharyya, Sudip; Strohmayer, Tod E.

2005-01-01

We analyse Rossi X-ray Timing Explorer (RXTE) Proportional Counter Array (PCA) data of a double-peaked burst from the low mass X-ray binary (LMXB) 4U 1636-536 that shows no evidence for photospheric radius expansion (PRE). We find that the X-ray emitting area on the star increases with time as the burst progresses, even though the photosphere does not expand. We argue that this is a strong indication of thermonuclear flame spreading on the stellar surface during such bursts. We propose a model for such double-peaked bursts, based on thermonuclear flame spreading, that can qualitatively explain their essential features, as well as the rarity of these bursts.

Magnetic Reconnection Driven by Thermonuclear Burning

NASA Astrophysics Data System (ADS)

Gatto, R.; Coppi, B.

2017-10-01

Considering that fusion reaction products (e.g. α-particles) deposit their energy on the electrons, the relevant thermal energy balance equation is characterized by a fusion source term, a relatively large longitudinal thermal conductivity and an appropriate transverse thermal conductivity. Then, looking for modes that are radially localized around rational surfaces, reconnected field configurations are found that can be sustained by the electron thermal energy source due to fusion reactions. Then this process can be included in the category of endogenous reconnection processes and may be viewed as a form of the thermonuclear instability that can develop in an ignited inhomogeneous plasma. A complete analysis of the equations supporting the relevant theory is reported. Sponsored in part by the U.S. DoE.

Upgrade of the IGN-14 neutron generator for research on detection of fusion-plasma products

NASA Astrophysics Data System (ADS)

Igielski, Andrzej; Kurowski, Arkadiusz; Janik, Władysław; Gabańska, Barbara; Woźnicka, Urszula

2015-10-01

The fast neutron generator (IGN-14) at the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Kraków (Poland) is a laboratory multi-purpose experimental device. Neutrons are produced in a beam-target D-D or D-T reactions. A new vacuum chamber installed directly to the end of the ion guide of IGN-14 makes it possible to measure not only neutrons but also alpha particles in the presence of a mixed radiation field of other accompanying reaction products. The new experimental setup allows test detectors dedicated to spectrometric measurements of thermonuclear fusion reaction products.

Frontier of Fusion Research: Path to the Steady State Fusion Reactor by Large Helical Device

NASA Astrophysics Data System (ADS)

Motojima, Osamu

2006-12-01

The ITER, the International Thermonuclear Experimental Reactor, which will be built in Cadarache in France, has finally started this year, 2006. Since the thermal energy produced by fusion reactions divided by the external heating power, i.e., the Q value, will be larger than 10, this is a big step of the fusion research for half a century trying to tame the nuclear fusion for the 6.5 Billion people on the Earth. The source of the Sun's power is lasting steadily and safely for 8 Billion years. As a potentially safe environmentally friendly and economically competitive energy source, fusion should provide a sustainable future energy supply for all mankind for ten thousands of years. At the frontier of fusion research important milestones are recently marked on a long road toward a true prototype fusion reactor. In its own merits, research into harnessing turbulent burning plasmas and thereby controlling fusion reaction, is one of the grand challenges of complex systems science. After a brief overview of a status of world fusion projects, a focus is given on fusion research at the National Institute for Fusion Science (NIFS) in Japan, which is playing a role of the Inter University Institute, the coordinating Center of Excellence for academic fusion research and by the Large Helical Device (LHD), the world's largest superconducting heliotron device, as a National Users' facility. The current status of LHD project is presented focusing on the experimental program and the recent achievements in basic parameters and in steady state operations. Since, its start in a year 1998, a remarkable progress has presently resulted in the temperature of 140 Million degree, the highest density of 500 Thousand Billion/cc with the internal density barrier (IDB) and the highest steady average beta of 4.5% in helical plasma devices and the largest total input energy of 1.6 GJ, in all magnetic confinement fusion devices. Finally, a perspective is given of the ITER Broad Approach program as an integrated part of ITER and Development of Fusion Energy project Agreement. Moreover, the relationship with the NIFS' new parent organization the National Institutes of Natural Sciences and with foreign research institutions is briefly explained.

A mixed helium-oxygen shell in some core-collapse supernova progenitors

NASA Astrophysics Data System (ADS)

Gofman, Roni Anna; Gilkis, Avishai; Soker, Noam

2018-04-01

We evolve models of rotating massive stars up to the stage of iron core collapse using the MESA code and find a shell with a mixed composition of primarily helium and oxygen in some cases. In the parameter space of initial masses of 13-40M⊙ and initial rotation velocities of 0-450 kms-1 that we investigate, we find a mixed helium-oxygen (He-O) shell with a significant total He-O mass and with a helium to oxygen mass ratio in the range of 0.5-2 only for a small fraction of the models. While the shell formation due to mixing is instigated by rotation, the pre-collapse rotation rate is not very high. The fraction of models with a shell of He-O composition required for an energetic collapse-induced thermonuclear explosion is small, as is the fraction of models with high specific angular momentum, which can aid the thermonuclear explosion by retarding the collapse. Our results suggest that the collapse-induced thermonuclear explosion mechanism that was revisited recently can account for at most a small fraction of core-collapse supernovae. The presence of such a mixed He-O shell still might have some implications for core-collapse supernovae, such as some nucleosynthesis processes when jets are present, or might result in peculiar sub-luminous core-collapse supernovae.

A mixed helium-oxygen shell in some core-collapse supernova progenitors

NASA Astrophysics Data System (ADS)

Gofman, Roni Anna; Gilkis, Avishai; Soker, Noam

2018-07-01

We evolve models of rotating massive stars up to the stage of iron core collapse using the MESA code and find a shell with a mixed composition of primarily helium and oxygen in some cases. In the parameter space of initial masses of 13-40 M⊙ and initial rotation velocities of 0-450 km s-1 that we investigate, we find a mixed helium-oxygen (He-O) shell with a significant total He-O mass and with a helium to oxygen mass ratio in the range of 0.5-2 only for a small fraction of the models. While the shell formation due to mixing is instigated by rotation, the pre-collapse rotation rate is not very high. The fraction of models with a shell of He-O composition required for an energetic collapse-induced thermonuclear explosion is small, as is the fraction of models with high specific angular momentum, which can aid the thermonuclear explosion by retarding the collapse. Our results suggest that the collapse-induced thermonuclear explosion mechanism that was revisited recently can account for at most a small fraction of core-collapse supernovae. The presence of such a mixed He-O shell still might have some implications for core-collapse supernovae, such as some nucleosynthesis processes when jets are present, or might result in peculiar sub-luminous core-collapse supernovae.

Cloud heights and stratospheric injections resulting from a thermonuclear war

NASA Astrophysics Data System (ADS)

Manins, P. C.

Two consequences of a major thermonuclear war are the injection of fireball material into the atmosphere and the production of vast quantities of dense smoke from fires which are ignited by the blasts. A major concern for assessment of impact on the environment is the height reached by this material. Fireball rise data are presented and a model for the plume rise from large fires in standard ambient conditions is validated with available data. It is concluded that injection of bomb debris into the stratosphere at mid and high latitudes should take place for all explosions with yield greater than approx. 30 kt of TNT equivalent. At low latitudes yields greater than 1 Mt are evidently required. Thus most fireball material would reach into the stratosphere under recently postulated scenarios. Fires would require a power output of 1.5 × 10 7 MW at middle and higher latitudes and 8 × 10 7 MW at low latitudes for significant injection of smoke into the stratosphere in standard conditions. Study of possible fires ignited in a thermonuclear war in rural and urban areas suggests that smoke from rural fires would reach the tropopause but that significant injections into the stratosphere are unlikely. Conflagration of large, medium- and high-density city-centres would, it is predicted, result in much smoke reaching to the tropopause and into the lower stratosphere at higher but not at low latitudes.

Research at the Institute of Astronomy and Astrophysics of the Université Libre de Bruxelles

NASA Astrophysics Data System (ADS)

Karinkuzhi, Drisya; Chamel, Nicolas; Goriely, Stéphane; Jorissen, Alain; Pourbaix, Dimitri; Siess, Lionel; Van Eck, Sophie

2018-04-01

Over the years, a coherent research strategy has developed in the field of stellar physics at the Institute of Astronomy and Astrophysics (IAA). It involves observational studies (chemical composition of giant stars, binary properties, tomography of stellar atmospheres) that make use of the large ESO telescopes as well as of other major instruments. The presence of a high-resolution spectrograph on the 3.6-m Devasthal Optical Telescope (DOT) would therefore be highly beneficial to IAA research. These observations are complemented and supported by theoretical studies of mass transfer in binary systems, of standard and non-standard stellar evolution (including the modelling of stellar hydrodynamical nuclear burning for application to certain thermonuclear supernovae) and of nuclear astrophysics (a field in which IAA has been recognized for a long time as an international centre of excellence), including the theory of nucleosynthesis. IAA also addresses the end-points of stellar evolution as it is carrying out research on the compact remnants of stellar evolution of massive stars: neutron stars.

Dynamic high energy density plasma environments at the National Ignition Facility for nuclear science research

NASA Astrophysics Data System (ADS)

Cerjan, Ch J.; Bernstein, L.; Berzak Hopkins, L.; Bionta, R. M.; Bleuel, D. L.; Caggiano, J. A.; Cassata, W. S.; Brune, C. R.; Frenje, J.; Gatu-Johnson, M.; Gharibyan, N.; Grim, G.; Hagmann, Chr; Hamza, A.; Hatarik, R.; Hartouni, E. P.; Henry, E. A.; Herrmann, H.; Izumi, N.; Kalantar, D. H.; Khater, H. Y.; Kim, Y.; Kritcher, A.; Litvinov, Yu A.; Merrill, F.; Moody, K.; Neumayer, P.; Ratkiewicz, A.; Rinderknecht, H. G.; Sayre, D.; Shaughnessy, D.; Spears, B.; Stoeffl, W.; Tommasini, R.; Yeamans, Ch; Velsko, C.; Wiescher, M.; Couder, M.; Zylstra, A.; Schneider, D.

2018-03-01

The generation of dynamic high energy density plasmas in the pico- to nano-second time domain at high-energy laser facilities affords unprecedented nuclear science research possibilities. At the National Ignition Facility (NIF), the primary goal of inertial confinement fusion research has led to the synergistic development of a unique high brightness neutron source, sophisticated nuclear diagnostic instrumentation, and versatile experimental platforms. These novel experimental capabilities provide a new path to investigate nuclear processes and structural effects in the time, mass and energy density domains relevant to astrophysical phenomena in a unique terrestrial environment. Some immediate applications include neutron capture cross-section evaluation, fission fragment production, and ion energy loss measurement in electron-degenerate plasmas. More generally, the NIF conditions provide a singular environment to investigate the interplay of atomic and nuclear processes such as plasma screening effects upon thermonuclear reactivity. Achieving enhanced understanding of many of these effects will also significantly advance fusion energy research and challenge existing theoretical models.

SPIRAL INSTABILITY CAN DRIVE THERMONUCLEAR EXPLOSIONS IN BINARY WHITE DWARF MERGERS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kashyap, Rahul; Fisher, Robert; García-Berro, Enrique

2015-02-10

Thermonuclear, or Type Ia supernovae (SNe Ia), originate from the explosion of carbon–oxygen white dwarfs, and serve as standardizable cosmological candles. However, despite their importance, the nature of the progenitor systems that give rise to SNe Ia has not been hitherto elucidated. Observational evidence favors the double-degenerate channel in which merging white dwarf binaries lead to SNe Ia. Furthermore, significant discrepancies exist between observations and theory, and to date, there has been no self-consistent merger model that yields a SNe Ia. Here we show that a spiral mode instability in the accretion disk formed during a binary white dwarf mergermore » leads to a detonation on a dynamical timescale. This mechanism sheds light on how white dwarf mergers may frequently yield SNe Ia.« less

A novel digital neutron flux monitor for international thermonuclear experimental reactor

NASA Astrophysics Data System (ADS)

Xiang, ZHOU; Zihao, LIU; Chao, CHEN; Renjie, ZHU; Li, ZHAO; Lingfeng, WEI; Zejie, YIN

2018-04-01

A novel full-digital real-time neutron flux monitor (NFM) has been developed for the International Thermonuclear Experimental Reactor. A measurement range of 109 counts per second is achieved with 3 different sensitive fission chambers. The Counting mode and Campbelling mode have been combined as a means to achieve higher measurement range. The system is based on high speed as well as parallel and pipeline processing of the field programmable gate array and has the ability to upload raw-data of analog-to-digital converter in real-time through the PXIe platform. With the advantages of the measurement range, real time performance and the ability of raw-data uploading, the digital NFM has been tested in HL-2A experiments and reflected good experimental performance.

Fermi Establishes Classical Novae as a Distinct Class of Gamma-ray Sources

NASA Technical Reports Server (NTRS)

Ackermann, M.; Ajello, M.; Albert, A.; Baldini, L.; Ballet, J.; Bastieri, D.; Bellazzini, R.; Bissaldi, E.; Blandford, R. D.; Bloom, E. D.;

Fermi establishes classical novae as a distinct class of gamma-ray sources

DOE PAGES

Cheung, C. C.

2014-07-31

A classical nova results from runaway thermonuclear explosions on the surface of a white dwarf that accretes matter from a low-mass main-sequence stellar companion. In 2012 and 2013, three novae were detected in γ rays and stood in contrast to the first γ-ray detected nova V407 Cygni 2010, which belongs to a rare class of symbiotic binary systems. Despite likely differences in the compositions and masses of their white dwarf progenitors, the three classical novae are similarly characterized as soft spectrum transient γ-ray sources detected over 2-3 week durations. The γ-ray detections point to unexpected high-energy particle acceleration processes linkedmore » to the mass ejection from thermonuclear explosions in an unanticipated class of Galactic γ-ray sources.« less

Method and system to directly produce electrical power within the lithium blanket region of a magnetically confined, deuterium-tritium (DT) fueled, thermonuclear fusion reactor

DOEpatents

Woolley, Robert D.

1999-01-01

A method for integrating liquid metal magnetohydrodynamic power generation with fusion blanket technology to produce electrical power from a thermonuclear fusion reactor located within a confining magnetic field and within a toroidal structure. A hot liquid metal flows from a liquid metal blanket region into a pump duct of an electromagnetic pump which moves the liquid metal to a mixer where a gas of predetermined pressure is mixed with the pressurized liquid metal to form a Froth mixture. Electrical power is generated by flowing the Froth mixture between electrodes in a generator duct. When the Froth mixture exits the generator the gas is separated from the liquid metal and both are recycled.

NASA superconducting magnetic mirror facility

NASA Technical Reports Server (NTRS)

Reinmann, J. J.; Swanson, M. C.; Nichols, C. R.; Obloy, S. J.; Nagy, L. A.; Brady, F. J.

1973-01-01

This report summarizes the design details and initial test results of a superconducting magnetic mirror facility that has been constructed at NASA Lewis Research Center for use in thermonuclear research. The magnet system consists of four solenoidal coils which are individually rated at 5.0 T. Each coil is composed of an inner, middle, and outer winding. The inner winding is wound of stabilized Nb3SN superconducting ribbon, and the middle and outer windings are wound of stabilized Nb-Ti superconducting wire. When arranged in the mirror geometry, the four coils will produce 8.7 T at the mirrors and a 1.8 mirror ratio. The magnet has a 41-cm diameter clear bore which is open to atmosphere. Distance between the mirrors is 111 cm. Presently there are only three magnets in the facility; the fourth magnet is being rebuilt.

Perspectives for the high field approach in fusion research and advances within the Ignitor Program

NASA Astrophysics Data System (ADS)

Coppi, B.; Airoldi, A.; Albanese, R.; Ambrosino, G.; Belforte, G.; Boggio-Sella, E.; Cardinali, A.; Cenacchi, G.; Conti, F.; Costa, E.; D'Amico, A.; Detragiache, P.; De Tommasi, G.; DeVellis, A.; Faelli, G.; Ferraris, P.; Frattolillo, A.; Giammanco, F.; Grasso, G.; Lazzaretti, M.; Mantovani, S.; Merriman, L.; Migliori, S.; Napoli, R.; Perona, A.; Pierattini, S.; Pironti, A.; Ramogida, G.; Rubinacci, G.; Sassi, M.; Sestero, A.; Spillantini, S.; Tavani, M.; Tumino, A.; Villone, F.; Zucchi, L.

2015-05-01

The Ignitor Program maintains the objective of approaching D-T ignition conditions by incorporating systematical advances made with relevant high field magnet technology and with experiments on high density well confined plasmas in the present machine design. An additional objective is that of charting the development of the high field line of experiments that goes from the Alcator machine to the ignitor device. The rationale for this class of experiments, aimed at producing poloidal fields with the highest possible values (compatible with proven safety factors of known plasma instabilities) is given. On the basis of the favourable properties of high density plasmas produced systematically by this line of machines, the envisioned future for the line, based on novel high field superconducting magnets, includes the possibility of investigating more advanced fusion burn conditions than those of the D-T plasmas for which Ignitor is designed. Considering that a detailed machine design has been carried out (Coppi et al 2013 Nucl. Fusion 53 104013), the advances made in different areas of the physics and technology that are relevant to the Ignitor project are reported. These are included within the following sections of the present paper: main components issues, assembly and welding procedures; robotics criteria; non-linear feedback control; simulations with three-dimensional structures and disruption studies; ICRH and dedicated diagnostics systems; anomalous transport processes including self-organization for fusion burning regimes and the zero-dimensional model; tridimensional structures of the thermonuclear instability and control provisions; superconducting components of the present machine; envisioned experiments with high field superconducting magnets.

The 14 MeV Neutron Irradiation Facility in MARIA Reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prokopowicz, R.; Pytel, K.; Dorosz, M.

2015-07-01

The MARIA reactor with thermal neutron flux density up to 3x10{sup 14} cm{sup -2} s{sup -1} and a number of vertical channels is well suited to material testing by thermal neutron treatment. Beside of that some fast neutron irradiation facilities are operated in MARIA reactor as well. One of them is thermal to 14 MeV neutron converter launched in 2014. It is especially devoted to fusion devices material testing irradiation. The ITER and DEMO research thermonuclear facilities are to be run using the deuterium - tritium fusion reaction. Fast neutrons (of energy approximately 14 MeV) resulting from the reaction aremore » essential to carry away the released thermonuclear energy and to breed tritium. However, constructional materials of which thermonuclear reactors are to be built must be specially selected to survive intense fluxes of fast neutrons. Strong sources of 14 MeV neutrons are needed if research on resistance of candidate materials to such fluxes is to be carried out effectively. Nuclear reactor-based converter capable to convert thermal neutrons into 14 MeV fast neutrons may be used to that purpose. The converter based on two stage nuclear reaction on lithium-6 and deuterium compounds leading to 14 MeV neutron production. The reaction chain is begun by thermal neutron capture by lithium-6 nucleus resulted in triton release. The neutron and triton transport calculations have been therefore carried-out to estimate the thermal to 14 MeV neutron conversion efficiency and optimize converter construction. The usable irradiation space of ca. 60 cm{sup 3} has been obtained. The released energy have been calculated. Heat transport has been asses to ensure proper device cooling. A set of thermocouples has been installed in converter to monitor its temperature distribution on-line. Influence of converter on reactor operation has been studied. Safety analyses of steady states and transients have been done. Performed calculations and analyses allow designing the converter and formulate its operation limits and conditions. During first tested operation of the converter the 14 MeV neutron flux density was estimated to 10{sup 9} cm{sup -2} s{sup -1}, whereas fast fission neutrons inside converter achieved 10{sup 12} cm{sup -2} s{sup -1}, and thermal neutrons were reduced down to 109 cm-2 s-1. Taking into account the feasibility of almost incessant converter operation for a number of months, its arisen as one of the most powerful (in terms of fluence), currently available 14 MeV neutron source. Such a converter currently under operation in the MARIA reactor core will be presented. (authors)« less

Application of dynamic mass spectrometers for investigations in the field of thermonuclear synthesis

NASA Astrophysics Data System (ADS)

Aruev, N. N.

2017-04-01

This review discusses the design, analytical characteristics, and some applications of two types of dynamic mass spectrometers that have been developed at the Ioffe Institute, Russian Academy of Sciences: the magnetic resonance mass spectrometer (MRMS) and time-of-flight mass spectrometer (TOFMS), the latter of which the inventors named the mass reflectron. With the aid of an MRMS, it was possible to measure the half-life of tritium, which is a fusion fuel candidate, and to start investigating how deuterium plasma interacts with the structural materials of the spherical tokamak Globus-M. The research done shows that mass reflectrons can be used successfully in the analysis of tritium-containing fusion fuel gas mixtures.

Summary Report on Controlled Thermonuclear Synthesis,

DTIC Science & Technology

stellarator and the tokamak. Adiabatic magnetic traps are also briefly discussed, as well as the plasma focus . The paper is a very brief generalization of the current state of high-temperature plasma physics. (Author)

Lawson criterion in cyclotron heating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demutskii, V.P.; Polovin, R.V.

1975-07-01

Stochastic heating of plasma particles is of great interest for controlled thermonuclear reactions. The ion velocity distribution function is described for the case of cyclotron heating. The Lawson criterion applied to this distribution is described. (MOW)

Advantages of Fast Ignition Scenarios with Two Hot Spots for Space Propulsion Systems

NASA Astrophysics Data System (ADS)

Shmatov, M. L.

The use of the fast ignition scenarios with the attempts to create two hot spots in one blob of the compressed thermonuclear fuel or, briefly, scenarios with two hot spots in space propulsion systems is proposed. The model, predicting that for such scenarios the probability pf of failure of ignition of thermonuclear microexplosion can be significantly less than that for the similar scenarios with the attempts to create one hot spot in one blob of the compressed fuel, is presented. For space propulsion systems consuming a relatively large amount of propellant, a decrease in pf due to the choice of the scenario with two hot spots can result in large, for example, two-fold, increase in the payload mass. Other advantages of the scenarios with two hot spots and some problems related to them are considered.

Gain curves and hydrodynamic modeling for shock ignition

NASA Astrophysics Data System (ADS)

Lafon, M.; Ribeyre, X.; Schurtz, G.

2010-05-01

Ignition of a precompressed thermonuclear fuel by means of a converging shock is now considered as a credible scheme to obtain high gains for inertial fusion energy. This work aims at modeling the successive stages of the fuel time history, from compression to final thermonuclear combustion, in order to provide the gain curves of shock ignition (SI). The leading physical mechanism at work in SI is pressure amplification, at first by spherical convergence, and by collision with the shock reflected at center during the stagnation process. These two effects are analyzed, and ignition conditions are provided as functions of the shock pressure and implosion velocity. Ignition conditions are obtained from a non-isobaric fuel assembly, for which we present a gain model. The corresponding gain curves exhibit a significantly lower ignition threshold and higher target gains than conventional central ignition.

History of 232-F, tritium extraction processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blackburn, G.W.

1994-08-01

In 1950 the Atomic Energy Commission authorized the Savannah River Project principally for the production of tritium and plutonium-239 for use in thermonuclear weapons. 232-F was built as an interim facility in 1953--1954, at a cost of $3.9M. Tritium extraction operations began in October, 1955, after the reactor and separations startups. In July, 1957 a larger tritium facility began operation in 232-H. In 1958 the capacity of 232-H was doubled. Also, in 1957 a new task was assigned to Savannah River, the loading of tritium into reservoirs that would be actual components of thermonuclear weapons. This report describes the historymore » of 232-F, the process for tritium extraction, and the lessons learned over the years that were eventually incorporated into the new Replacement Tritium Facility.« less

Effect of high Z impurities on the ignition and Lawson conditions for a thermonuclear reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meade, D.M.

1973-06-01

The recent advances in plasma heating and confinement using Tokamak devices have produced plasmas which approach thermonuclear conditions. Substantial amounts (0.1 to 1%) of partially stripped high Z impurities have been observed in these discharges. These high Z impurities (Fe,Mo,W) are presumably due to plasma bombardment of the limiter and vacuum chamber wall. Since the plasma energy will be increasing sharply in the next sequence of experiments from approx. =1kJ in ST tokamak to approx. =3MJ in PLT and up to approx. =100MJ in a feasibility experiment, the bombardment of the wall and limiter will become increasingly important. In thismore » paper, the effects of high Z impurities on the ignition and Lawson conditions for a DT reactor are calculated. 7 refs., 2 figs.« less

3D Simulations of Supernova Remnants from Type Ia Supernova Models

NASA Astrophysics Data System (ADS)

Johnson, Heather; Reynolds, S. P.; Frohlich, C.; Blondin, J. M.

2014-01-01

Type Ia supernovae (SNe) originate from thermonuclear explosions of white dwarfs. A great deal is still unknown about the explosion mechanisms, particularly the degree of asymmetry. However, Type Ia supernova remnants (SNRs) can bear the imprint of asymmetry long after the explosion. A SNR of interest is G1.9+0.3, the youngest Galactic SNR, which demonstrates an unusual spatial distribution of elements in the ejecta. While its X-ray spectrum is dominated by synchrotron emission, spectral lines of highly ionized Si, S, and Fe are seen in a few locations, with Fe near the edge of the remnant and with strongly varying Fe/Si ratios. An asymmetric explosion within the white dwarf progenitor may be necessary to explain these unusual features of G1.9+0.3, in particular the shocked Fe at large radii. We use the VH-1 hydrodynamics code to evolve initial Type Ia explosion models in 1, 2, and 3 dimensions at an age of 100 seconds provided by other researchers to study asymmetry, the ignition properties, and the nucleosynthesis resulting from these explosions. We follow the evolution of these models interacting with a uniform external medium to a few hundred years in age. We find the abundance and location of ejecta elements from our models to be inconsistent with the observations of G1.9+0.3; while our models show asymmetric element distributions, we find no tendency for iron-group elements to be found beyond intermediate-mass elements, or for significant iron to be reverse-shocked at all at the age of G1.9+0.3. We compare the amounts of shocked iron-group and intermediate-mass elements as a function of time in the different models. Some new kind of explosion asymmetry may be required to explain G1.9+0.3. This work was performed as part of NC State University's Undergraduate Research in Computational Astrophysics (URCA) program, an REU program supported by the National Science Foundation through award AST-1032736.

Tritium environmental transport studies at TFTR

NASA Astrophysics Data System (ADS)

Ritter, P. D.; Dolan, T. J.; Longhurst, G. R.

1993-06-01

Environmental tritium concentrations will be measured near the Tokamak Fusion Test Reactor (TFTR) to help validate dynamic models of tritium transport in the environment. For model validation the database must contain sequential measurements of tritium concentrations in key environmental compartments. Since complete containment of tritium is an operational goal, the supplementary monitoring program should be able to glean useful data from an unscheduled acute release. Portable air samplers will be used to take samples automatically every 4 hours for a week after an acute release, thus obtaining the time resolution needed for code validation. Samples of soil, vegetation, and foodstuffs will be gathered daily at the same locations as the active air monitors. The database may help validate the plant/soil/air part of tritium transport models and enhance environmental tritium transport understanding for the International Thermonuclear Experimental Reactor (ITER).

A new look at low-energy nuclear reaction research.

PubMed

Krivit, Steven B; Marwan, Jan

2009-10-01

This paper presents a new look at low-energy nuclear reaction research, a field that has developed from one of the most controversial subjects in science, "cold fusion." Early in the history of this controversy, beginning in 1989, a strong polarity existed; many scientists fiercely defended the claim of new physical effects as well as a new process in which like-charged atomic nuclei overcome the Coulomb barrier at normal temperatures and pressures. Many other scientists considered the entire collection of physical observations-along with the hypothesis of a "cold fusion"--entirely a mistake. Twenty years later, some people who had dismissed the field in its entirety are considering the validity of at least some of the reported experimental phenomena. As well, some researchers in the field are wondering whether the underlying phenomena may be not a fusion process but a neutron capture/absorption process. In 2002, a related tabletop form of thermonuclear fusion was discovered in the field of acoustic inertial confinement fusion. We briefly review some of this work, as well.

The status of beryllium technology for fusion

NASA Astrophysics Data System (ADS)

Scaffidi-Argentina, F.; Longhurst, G. R.; Shestakov, V.; Kawamura, H.

2000-12-01

Beryllium was used for a number of years in the Joint European Torus (JET), and it is planned to be used extensively on the lower heat-flux surfaces of the reduced technical objective/reduced cost international thermonuclear experimental reactor (RTO/RC ITER). It has been included in various forms in a number of tritium breeding blanket designs. There are technical advantages but also a number of safety issues associated with the use of beryllium. Research in a variety of technical areas in recent years has revealed interesting issues concerning the use of beryllium in fusion. Progress in this research has been presented at a series of International Workshops on Beryllium Technology for Fusion. The most recent workshop was held in Karlsruhe, Germany on 15-17 September 1999. In this paper, a summary of findings presented there and their implications for the use of beryllium in the development of fusion reactors are presented.

Indirect drive ignition at the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meezan, N. B.; Edwards, M. J.; Hurricane, O. A.

This article reviews scientific results from the pursuit of indirect drive ignition on the National Ignition Facility (NIF) and describes the program's forward looking research directions. In indirect drive on the NIF, laser beams heat an x-ray enclosure called a hohlraum that surrounds a spherical pellet. X-ray radiation ablates the surface of the pellet, imploding a thin shell of deuterium/tritium (DT) that must accelerate to high velocity (v > 350 km s -1) and compress by a factor of several thousand. Since 2009, substantial progress has been made in understanding the major challenges to ignition: Rayleigh Taylor (RT) instability seededmore » by target imperfections; and low-mode asymmetries in the hohlraum x-ray drive, exacerbated by laser-plasma instabilities (LPI). Requirements on velocity, symmetry, and compression have been demonstrated separately on the NIF but have not been achieved simultaneously. We now know that the RT instability, seeded mainly by the capsule support tent, severely degraded DT implosions from 2009–2012. Experiments using a 'high-foot' drive with demonstrated lower RT growth improved the thermonuclear yield by a factor of 10, resulting in yield amplification due to alpha particle heating by more than a factor of 2. However, large time dependent drive asymmetry in the LPI-dominated hohlraums remains unchanged, preventing further improvements. High fidelity 3D hydrodynamic calculations explain these results. In conclusion, future research efforts focus on improved capsule mounting techniques and on hohlraums with little LPI and controllable symmetry. In parallel, we are pursuing improvements to the basic physics models used in the design codes through focused physics experiments.« less

Indirect drive ignition at the National Ignition Facility

DOE PAGES

Meezan, N. B.; Edwards, M. J.; Hurricane, O. A.; ...

2016-10-27

This article reviews scientific results from the pursuit of indirect drive ignition on the National Ignition Facility (NIF) and describes the program's forward looking research directions. In indirect drive on the NIF, laser beams heat an x-ray enclosure called a hohlraum that surrounds a spherical pellet. X-ray radiation ablates the surface of the pellet, imploding a thin shell of deuterium/tritium (DT) that must accelerate to high velocity (v > 350 km s -1) and compress by a factor of several thousand. Since 2009, substantial progress has been made in understanding the major challenges to ignition: Rayleigh Taylor (RT) instability seededmore » by target imperfections; and low-mode asymmetries in the hohlraum x-ray drive, exacerbated by laser-plasma instabilities (LPI). Requirements on velocity, symmetry, and compression have been demonstrated separately on the NIF but have not been achieved simultaneously. We now know that the RT instability, seeded mainly by the capsule support tent, severely degraded DT implosions from 2009–2012. Experiments using a 'high-foot' drive with demonstrated lower RT growth improved the thermonuclear yield by a factor of 10, resulting in yield amplification due to alpha particle heating by more than a factor of 2. However, large time dependent drive asymmetry in the LPI-dominated hohlraums remains unchanged, preventing further improvements. High fidelity 3D hydrodynamic calculations explain these results. In conclusion, future research efforts focus on improved capsule mounting techniques and on hohlraums with little LPI and controllable symmetry. In parallel, we are pursuing improvements to the basic physics models used in the design codes through focused physics experiments.« less

The quest for a z-pinch based fusion energy source—a historical perspective

NASA Astrophysics Data System (ADS)

Sethian, John

1997-05-01

Ever since 1958, when Oscar Anderson observed copious neutrons emanating from a "magnetically self-constricted column of deuterium plasma," scientists have attempted to develop the simple linear pinch into a fusion power source. After all, simple calculations show that if one can pass a current of slightly less than 2 million amperes through a stable D-T plasma, then one could achieve not just thermonuclear break-even, but thermonuclear gain. Moreover, several reactor studies have shown that a simple linear pinch could be the basis for a very attractive fusion system. The problem is, of course, that the seemingly simple act of passing 2 MA through a stable pinch has proven to be quite difficult to accomplish. The pinch tends to disrupt due to instabilities, either by the m=0 (sausage) or m=1 (kink) modes. Curtailing the growth of these instabilities has been the primary thrust of z-pinch fusion research, and over the years a wide variety of formation techniques have been tried. The early pinches were driven by relatively slow capacitive discharges and were formed by imploding a plasma column. The advent of fast pulsed power technology brought on a whole new repertoire of formation techniques, including: fast implosions, laser or field-enhanced breakdown in a uniform volume of gas, a discharge inside a small capillary, a frozen deuterium fiber isolated by vacuum, and staged concepts in which one pinch implodes upon another. And although none of these have yet to be successful, some have come tantalizingly close. This paper will review the history of this four-decade long quest for fusion power.

ON THE EFFECT OF EXPLOSIVE THERMONUCLEAR BURNING ON THE ACCRETED ENVELOPES OF WHITE DWARFS IN CATACLYSMIC VARIABLES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sion, Edward M.; Sparks, Warren, E-mail: edward.sion@villanova.edu, E-mail: warrensparks@comcast.net

2014-11-20

The detection of heavy elements at suprasolar abundances in the atmospheres of some accreting white dwarfs in cataclysmic variables (CVs), coupled with the high temperatures needed to produce these elements, requires explosive thermonuclear burning. The central temperatures of any formerly more massive secondary stars in CVs undergoing hydrostatic CNO burning are far too low to produce these elements. Evidence is presented that at least some CVs contain donor secondaries that have been contaminated by white dwarf remnant burning during the common envelope phase and are transferring this material back to the white dwarf. This scenario does not exclude the channelmore » in which formerly more massive donor stars underwent CNO processing in systems with thermal timescale mass transfer. Implications for the progenitors of CVs are discussed and a new scenario for the white dwarf's accretion-nova-outburst is given.« less

The Dynamic Mutation Characteristics of Thermonuclear Reaction in Tokamak

PubMed Central

Li, Jing; Quan, Tingting; Zhang, Wei; Deng, Wei

2014-01-01

The stability and bifurcations of multiple limit cycles for the physical model of thermonuclear reaction in Tokamak are investigated in this paper. The one-dimensional Ginzburg-Landau type perturbed diffusion equations for the density of the plasma and the radial electric field near the plasma edge in Tokamak are established. First, the equations are transformed to the average equations with the method of multiple scales and the average equations turn to be a Z 2-symmetric perturbed polynomial Hamiltonian system of degree 5. Then, with the bifurcations theory and method of detection function, the qualitative behavior of the unperturbed system and the number of the limit cycles of the perturbed system for certain groups of parameter are analyzed. At last, the stability of the limit cycles is studied and the physical meaning of Tokamak equations under these parameter groups is given. PMID:24892099

Diffuse Galactic antimatter from faint thermonuclear supernovae in old stellar populations

NASA Astrophysics Data System (ADS)

Crocker, Roland M.; Ruiter, Ashley J.; Seitenzahl, Ivo R.; Panther, Fiona H.; Sim, Stuart; Baumgardt, Holger; Möller, Anais; Nataf, David M.; Ferrario, Lilia; Eldridge, J. J.; White, Martin; Tucker, Brad E.; Aharonian, Felix

2017-06-01

Our Galaxy hosts the annihilation of a few 1043 low-energy positrons every second. Radioactive isotopes capable of supplying such positrons are synthesized in stars, stellar remnants and supernovae. For decades, however, there has been no positive identification of a main stellar positron source, leading to suggestions that many positrons originate from exotic sources like the Galaxy's central supermassive black hole or dark matter annihilation. Here we show that a single type of transient source, deriving from stellar populations of age 3-6 Gyr and yielding ∼0.03 M ⊙ of the positron emitter 44Ti, can simultaneously explain the strength and morphology of the Galactic positron annihilation signal and the Solar System abundance of the 44Ti decay product 44Ca. This transient is likely the merger of two low-mass white dwarfs, observed in external galaxies as the sub-luminous, thermonuclear supernova known as SN 1991bg-like.

Burst Oscillation Probes of Neutron Stars and Nuclear Burning with LOFT

NASA Technical Reports Server (NTRS)

Strohmayer, Tod

2012-01-01

X-ray brightness oscillations during thermonuclear X-ray bursts--burst oscillations--have provided a new probe of neutron star spins as well as of the dependent nuclear burning processes. The frequency drift and amplitude evolution of the oscillations observed during bursts can in principle place constraints on the physics of thermonuclear flame spreading and the dynamics of the burning atmosphere. I use simulations appropriate to LOFT to explore the precision with which the time dependence of the oscillation frequency can be inferred. This can test, for example, different models for the frequency drift, such as up-lift versus geostrophic drift. I also explore the precision with which asymptotic frequencies can be constrained in order to estimate the capability for LOFT to detect the Doppler shifts induced by orbital motion of the neutron star from a sample of bursts at different orbital phases.

Thermonuclear 46Cr(p ,γ )47Mn rate in type-I x-ray bursts

NASA Astrophysics Data System (ADS)

He, J. J.; Parikh, A.; Xu, Y.; Zhang, Y. H.; Zhou, X. H.; Xu, H. S.

2017-10-01

The thermonuclear rate of the 46Cr(p ,γ )47Mn reaction has been determined using a newly evaluated proton separation energy of Sp(47Mn) =380 ±30 keV and nuclear structure information from the mirror nucleus 47Ti. The astrophysical impact of this new rate and previously available rates has been investigated through one-zone postprocessing type-I x-ray burst calculations. The present 46Cr(p ,γ )47Mn rate leads to a mass fraction at A =46 that is 60 times larger than that obtained using a statistical model rate. The new results constrain the calculated maximum and minimum mass fractions at A =46 and A =48 to be within factors of 12 and 4, respectively. Experimental studies of the level structure of 47Mn near the proton threshold are required to improve these model predictions.

Stellar dynamics. The fastest unbound star in our Galaxy ejected by a thermonuclear supernova.

PubMed

Geier, S; Fürst, F; Ziegerer, E; Kupfer, T; Heber, U; Irrgang, A; Wang, B; Liu, Z; Han, Z; Sesar, B; Levitan, D; Kotak, R; Magnier, E; Smith, K; Burgett, W S; Chambers, K; Flewelling, H; Kaiser, N; Wainscoat, R; Waters, C

2015-03-06

Hypervelocity stars (HVSs) travel with velocities so high that they exceed the escape velocity of the Galaxy. Several acceleration mechanisms have been discussed. Only one HVS (US 708, HVS 2) is a compact helium star. Here we present a spectroscopic and kinematic analysis of US 708. Traveling with a velocity of ~1200 kilometers per second, it is the fastest unbound star in our Galaxy. In reconstructing its trajectory, the Galactic center becomes very unlikely as an origin, which is hardly consistent with the most favored ejection mechanism for the other HVSs. Furthermore, we detected that US 708 is a fast rotator. According to our binary evolution model, it was spun-up by tidal interaction in a close binary and is likely to be the ejected donor remnant of a thermonuclear supernova. Copyright © 2015, American Association for the Advancement of Science.

Minutes of the third annual meeting of the Panel on Reference Nuclear Data. [BNL, October 5, 1978

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burrows, T.W.; Stewart, L.; Coyne, J.J.

1979-05-01

The major activities of the meeting were as follows: welcome; organization, approval of minutes of the second meeting, and approval of agenda; review of nuclear data compilation and evaluation efforts (national and international efforts, master data files, publications); summary of 1977 panel meeting; definition of reference nuclear data; discussion of specific data needs and possible data center contributions (reactor physics, medicine and biology, controlled thermonuclear reactors and astrophysics); establishment of current interest and future direction of the panel; adjournment. Recommendations and action items are listed. Tables on nuclear data needs in applied physics, medicine and biology, and controlled thermonuclear reactorsmore » and astrophysics are presented. Appendixes include membership lists of various committees, summaries of publication activities, survey results, correspondence, and portions of the documents Proceedings of the Magnetic Fusion Energy Blanket and Shield Workshop and National Needs for Critically Evaluated Physical and Chemical Data. (RWR)« less

Fusion energy

NASA Astrophysics Data System (ADS)

1990-09-01

The main purpose of the International Thermonuclear Experimental Reactor (ITER) is to develop an experimental fusion reactor through the united efforts of many technologically advanced countries. The ITER terms of reference, issued jointly by the European Community, Japan, the USSR, and the United States, call for an integrated international design activity and constitute the basis of current activities. Joint work on ITER is carried out under the auspices of the International Atomic Energy Agency (IAEA), according to the terms of quadripartite agreement reached between the European Community, Japan, the USSR, and the United States. The site for joint technical work sessions is at the Max Planck Institute of Plasma Physics. Garching, Federal Republic of Germany. The ITER activities have two phases: a definition phase performed in 1988 and the present design phase (1989 to 1990). During the definition phase, a set of ITER technical characteristics and supporting research and development (R and D) activities were developed and reported. The present conceptual design phase of ITER lasts until the end of 1990. The objectives of this phase are to develop the design of ITER, perform a safety and environmental analysis, develop site requirements, define future R and D needs, and estimate cost, manpower, and schedule for construction and operation. A final report will be submitted at the end of 1990. This paper summarizes progress in the ITER program during the 1989 design phase.

Students' Knowledge of Nuclear Science and Its Connection with Civic Scientific Literacy in Two European Contexts: The Case of Newspaper Articles

NASA Astrophysics Data System (ADS)

Tsaparlis, Georgios; Hartzavalos, Sotiris; Nakiboğlu, Canan

2013-08-01

Nuclear science has uses and applications that are relevant and crucial for world peace and sustainable development, so knowledge of its basic concepts and topics should constitute an integral part of civic scientific literacy. We have used two newspaper articles that deal with uses of nuclear science that are directly relevant to life, society, economy, and international politics. One article discusses a new thermonuclear reactor, and the second one is about depleted uranium and its danger for health. 189 first-year undergraduate physics and primary education Greek students were given one of the two articles each, and asked to answer a number of accompanying questions dealing with knowledge that is part of the Greek high school curriculum. The study was repeated with 272 first-year undergraduate physics, physics education, science education, and primary education Turkish students. Acceptable or partially acceptable answers were provided on average by around 20 % of Greek and 11 % of Turkish students, while a large proportion (on the average, around 50 % of Greek and 27 % of Turkish students) abstained from answering the questions. These findings are disappointing, but should be seen in the light of the limited or no coverage of the relevant learning material in the Greek and the Turkish high-school programs. Student conceptual difficulties, misconceptions and implications for research and high school curricula are discussed.

A Simulink Library of cryogenic components to automatically generate control schemes for large Cryorefrigerators

NASA Astrophysics Data System (ADS)

Bonne, François; Alamir, Mazen; Hoa, Christine; Bonnay, Patrick; Bon-Mardion, Michel; Monteiro, Lionel

2015-12-01

In this article, we present a new Simulink library of cryogenics components (such as valve, phase separator, mixer, heat exchanger...) to assemble to generate model-based control schemes. Every component is described by its algebraic or differential equation and can be assembled with others to build the dynamical model of a complete refrigerator or the model of a subpart of it. The obtained model can be used to automatically design advanced model based control scheme. It also can be used to design a model based PI controller. Advanced control schemes aim to replace classical user experience designed approaches usually based on many independent PI controllers. This is particularly useful in the case where cryoplants are submitted to large pulsed thermal loads, expected to take place in future fusion reactors such as those expected in the cryogenic cooling systems of the International Thermonuclear Experimental Reactor (ITER) or the Japan Torus-60 Super Advanced Fusion Experiment (JT- 60SA). The paper gives the example of the generation of the dynamical model of the 400W@1.8K refrigerator and shows how to build a Constrained Model Predictive Control for it. Based on the scheme, experimental results will be given. This work is being supported by the French national research agency (ANR) through the ANR-13-SEED-0005 CRYOGREEN program.

Monte Carlo simulation of neutral-beam injection for mirror fusion reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, Ronald Lee

1979-01-01

Computer simulation techniques using the Monte Carlo method have been developed for application to the modeling of neutral-beam intection into mirror-confined plasmas of interest to controlled thermonuclear research. The energetic (10 to 300 keV) neutral-beam particles interact with the target plasma (T i ~ 10 to 100 keV) through electron-atom and ion-atom collisional ionization as well as ion-atom charge-transfer (charge-exchange) collisions to give a fractional trapping of the neutral beam and a loss of charge-transfer-produced neutrals which escape to bombard the reactor first wall. Appropriate interaction cross sections for these processes are calculated for the assumed anisotropic, non-Maxwellian plasma ionmore » phase-space distributions.« less

Dynamic high energy density plasma environments at the National Ignition Facility for nuclear science research

DOE PAGES

Cerjan, Ch J.; Bernstein, L.; Hopkins, L. Berzak; ...

2017-08-16

We present the generation of dynamic high energy density plasmas in the pico- to nano-second time domain at high-energy laser facilities affords unprecedented nuclear science research possibilities. At the National Ignition Facility (NIF), the primary goal of inertial confinement fusion research has led to the synergistic development of a unique high brightness neutron source, sophisticated nuclear diagnostic instrumentation, and versatile experimental platforms. These novel experimental capabilities provide a new path to investigate nuclear processes and structural effects in the time, mass and energy density domains relevant to astrophysical phenomena in a unique terrestrial environment. Some immediate applications include neutron capturemore » cross-section evaluation, fission fragment production, and ion energy loss measurement in electron-degenerate plasmas. More generally, the NIF conditions provide a singular environment to investigate the interplay of atomic and nuclear processes such as plasma screening effects upon thermonuclear reactivity. Lastly, achieving enhanced understanding of many of these effects will also significantly advance fusion energy research and challenge existing theoretical models.« less

Dynamic high energy density plasma environments at the National Ignition Facility for nuclear science research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cerjan, Ch J.; Bernstein, L.; Hopkins, L. Berzak

We present the generation of dynamic high energy density plasmas in the pico- to nano-second time domain at high-energy laser facilities affords unprecedented nuclear science research possibilities. At the National Ignition Facility (NIF), the primary goal of inertial confinement fusion research has led to the synergistic development of a unique high brightness neutron source, sophisticated nuclear diagnostic instrumentation, and versatile experimental platforms. These novel experimental capabilities provide a new path to investigate nuclear processes and structural effects in the time, mass and energy density domains relevant to astrophysical phenomena in a unique terrestrial environment. Some immediate applications include neutron capturemore » cross-section evaluation, fission fragment production, and ion energy loss measurement in electron-degenerate plasmas. More generally, the NIF conditions provide a singular environment to investigate the interplay of atomic and nuclear processes such as plasma screening effects upon thermonuclear reactivity. Lastly, achieving enhanced understanding of many of these effects will also significantly advance fusion energy research and challenge existing theoretical models.« less

Physics and technology of the arms race

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garwin, R.L.

1983-01-01

Traditional military concepts of superiority and effectiveness (as embodied in Lanchester's law) have little relevance to thermonuclear weapons, with their enormous effectiveness in destruction of society. Few are needed to saturate their deterrent effect, but their military effectiveness is limited. The evolution and future of strategic nuclear forces is discussed, and their declining marginal utility emphasized. Some calculations relevant to the nuclear confrontation are presented (Lanchester's Law; skin effect of VLF and ELF signals to submarines; the rocket equation; simple radar-range equation) and recommendations presented for future strategic forces and arms control initiatives. Recommended programs include a silo-based 12-ton single-warheadmore » missile (SICM), the development of buried-bomb defense of individual Minuteman silos, the completion of the deployment of air-launched cruise missiles on the B-52 fleet, and the development of small (1000-ton) submarines for basing ICBM-range missiles.« less

The surgical management of benign and malignant thyroid neoplasms in Marshall Islanders exposed to hydrogen bomb fallout.

PubMed

Dobyns, B M; Hyrmer, B A

1992-01-01

On March 1, 1954, a serious fallout accident occurred during the United States atomic testing program at Bikini in the Trust Territory of the Pacific Islands. Following the detonation of a large thermonuclear device (known as Bravo) an unexpected shift in winds resulted in deposition of radioactive debris on several inhabited atolls in the Marshall Islands. During the early post-detonation period military, sea, and air surveys traced the hottest portion of the parabolic cloud as it drifted in an ever widening pattern of diminishing concentration eastward and southeast of Bikini. The center of the cloud passed North of the Rongelap Atoll, which was the nearest inhabited atoll. This report concerns the development of thyroid lesions, the special circumstances encountered during thyroid surgery, and the results of the surgical management of benign and malignant lesions that were subsequently encountered in this population.

The development of fluorides for high power laser optics

NASA Astrophysics Data System (ADS)

Ready, J. F.; Vora, H.

1980-07-01

The laser assisted thermonuclear fusion program has need for improved optical materials with high transmission in the ultraviolet, and with low values of nonlinear index of refraction. Lithium fluoride possesses a combination of optical properties which are of use. Single crystalline LiF is limited by low mechanical strength. The technique of press forging to increase the mechanical strength is investigated. LiF single crystals were press forged over the temperature range 300 - 600 deg C to produce fine grained polycrystalline material. Optical homogenity at 633, stress birefringence, scattering at 633, residual absorption over the spectral range 339 - 3800 nm, and laser damage thresholds for 1 ns, 1064 nm and 700 ps, 266 nm laser pulses are evaluated. Single crystals can be press forged without seriously degrading their optical properties. Yield strength in compression, proportional limit and fracture strength in 3 and 4 point bending, fracture energy, and threshold for microyield are discussed.

Thermonuclear ignition by Z-pinch X-ray radiation produced by current of an explosive magnetic generator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garanin, S. G.; Ivanovskiy, A. V., E-mail: ivanovsky@elph.vniief.ru

2015-12-15

The scheme of a device based a superpower disk-type magnetic explosion generator to produce a pulse of X-ray radiation with the energy exceeding the target ignition threshold is described and validated.

Thermonuclear ignition by Z-pinch X-ray radiation produced by current of an explosive magnetic generator

NASA Astrophysics Data System (ADS)

Garanin, S. G.; Ivanovskiy, A. V.

2015-12-01

The scheme of a device based a superpower disk-type magnetic explosion generator to produce a pulse of X-ray radiation with the energy exceeding the target ignition threshold is described and validated.

FUSION ENERGY SCIENCES WORKSHOP ON PLASMA MATERIALS INTERACTIONS: Report on Science Challenges and Research Opportunities in Plasma Materials Interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maingi, Rajesh; Zinkle, Steven J.; Foster, Mark S.

2015-05-01

The realization of controlled thermonuclear fusion as an energy source would transform society, providing a nearly limitless energy source with renewable fuel. Under the auspices of the U.S. Department of Energy, the Fusion Energy Sciences (FES) program management recently launched a series of technical workshops to “seek community engagement and input for future program planning activities” in the targeted areas of (1) Integrated Simulation for Magnetic Fusion Energy Sciences, (2) Control of Transients, (3) Plasma Science Frontiers, and (4) Plasma-Materials Interactions aka Plasma-Materials Interface (PMI). Over the past decade, a number of strategic planning activities1-6 have highlighted PMI and plasmamore » facing components as a major knowledge gap, which should be a priority for fusion research towards ITER and future demonstration fusion energy systems. There is a strong international consensus that new PMI solutions are required in order for fusion to advance beyond ITER. The goal of the 2015 PMI community workshop was to review recent innovations and improvements in understanding the challenging PMI issues, identify high-priority scientific challenges in PMI, and to discuss potential options to address those challenges. The community response to the PMI research assessment was enthusiastic, with over 80 participants involved in the open workshop held at Princeton Plasma Physics Laboratory on May 4-7, 2015. The workshop provided a useful forum for the scientific community to review progress in scientific understanding achieved during the past decade, and to openly discuss high-priority unresolved research questions. One of the key outcomes of the workshop was a focused set of community-initiated Priority Research Directions (PRDs) for PMI. Five PRDs were identified, labeled A-E, which represent community consensus on the most urgent near-term PMI scientific issues. For each PRD, an assessment was made of the scientific challenges, as well as a set of actions to address those challenges. No prioritization was attempted amongst these five PRDs. We note that ITER, an international collaborative project to substantially extend fusion science and technology, is implicitly a driver and beneficiary of the research described in these PRDs; specific ITER issues are discussed in the background and PRD chapters. For succinctness, we describe these PRDs directly below; a brief introduction to magnetic fusion and the workshop process/timeline is given in Chapter I, and panelists are listed in the Appendix.« less

Neutron generation from Z-pinches

NASA Astrophysics Data System (ADS)

Vikhrev, V. V.; Korolev, V. D.

2007-05-01

Recent advances in both experimental and theoretical studies on neutron generation in various Z-pinch facilities are reviewed. The main methods for enhancing neutron emission from the Z-pinch plasma are described, and the problems of igniting a thermonuclear burn wave in this plasma are discussed.

Charge exchange system

DOEpatents

Anderson, Oscar A.

1978-01-01

An improved charge exchange system for substantially reducing pumping requirements of excess gas in a controlled thermonuclear reactor high energy neutral beam injector. The charge exchange system utilizes a jet-type blanket which acts simultaneously as the charge exchange medium and as a shield for reflecting excess gas.

Effect of spatial nonuniformity of heating on compression and burning of a thermonuclear target under direct multibeam irradiation by a megajoule laser pulse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bel’kov, S. A.; Bondarenko, S. V.; Vergunova, G. A.

Direct-drive fusion targets are considered at present as an alternative to targets of indirect compression at a laser energy level of about 2 MJ. In this approach, the symmetry of compression and ignition of thermonuclear fuel play the major role. We report on the results of theoretical investigation of compression and burning of spherical direct-drive targets in the conditions of spatial nonuniformity of heating associated with a shift of the target from the beam center of focusing and possible laser radiation energy disbalance in the beams. The investigation involves numerous calculations based on a complex of 1D and 2D codesmore » RAPID, SEND (for determining the target illumination and the dynamics of absorption), DIANA, and NUT (1D and multidimensional hydrodynamics of compression and burning of targets). The target under investigation had the form of a two-layer shell (ablator made of inertial material CH and DT ice) filled with DT gas. We have determined the range of admissible variation of compression and combustion parameters of the target depending on the variation of the spatial nonuniformity of its heating by a multibeam laser system. It has been shown that low-mode (long-wavelength) perturbations deteriorate the characteristics of the central region due to less effective conversion of the kinetic energy of the target shell into the internal energy of the center. Local initiation of burning is also observed in off-center regions of the target in the case of substantial asymmetry of irradiation. In this case, burning is not spread over the entire volume of the DT fuel as a rule, which considerably reduces the thermonuclear yield as compared to that in the case of spherical symmetry and central ignition.« less

A burst from a thermonuclear runaway on an ONeMg white dwarf

NASA Technical Reports Server (NTRS)

Starrfield, S.; Politano, M.; Truran, J. W.; Sparks, W. M.

1992-01-01

Studies which examine the consequences of accretion, at rates of 10(exp -9) solar mass/yr and 10(exp -10) solar mass/yr, onto an ONeMg white dwarf with a mass of 1.35 solar masses are performed. In these studies, a Lagrangian, hydrodynamic, one-dimensional computer code was used. The code now includes a network with 89 nuclei up to Ca-40, elemental diffusion, new opacities, and new equation of state. The initial abundance distribution corresponded to a mixture that was enriched to either 25, 50, or 75 percent in products of carbon burning. The remaining material in each case is assumed to have a solar composition. The evolution of the thermonuclear runaway in the 1.35 solar mass white dwarf, with M = 10(exp -9) solar mass, produced peak temperatures in the shell source exceeding 300 million degrees. The sequence produced significant amounts of Na-22 from proton captures onto Ne-20 and significant amounts of Al-26 from proton captures on Mg-24. This sequence ejected 5.2 x 10(exp -6) solar mass moving with speeds from approximately 100 km/s to 2300 km/s. When the mass accretion rate was decreased to 10(exp -10) solar mass, the resulting thermonuclear runaway produced a shock that moved through the outer envelope of the white dwarf and raised the surface luminosity to L greater than 10(exp 7) solar luminosity and the effective temperature to values exceeding 10(exp 7) K. The interaction of the material expanding from off of the white dwarf with the accretion disk should produce a burst of gamma-rays.

First measurement of 30S+α resonant elastic scattering for the 30S(α ,p ) reaction rate

NASA Astrophysics Data System (ADS)

Kahl, D.; Yamaguchi, H.; Kubono, S.; Chen, A. A.; Parikh, A.; Binh, D. N.; Chen, J.; Cherubini, S.; Duy, N. N.; Hashimoto, T.; Hayakawa, S.; Iwasa, N.; Jung, H. S.; Kato, S.; Kwon, Y. K.; Nishimura, S.; Ota, S.; Setoodehnia, K.; Teranishi, T.; Tokieda, H.; Yamada, T.; Yun, C. C.; Zhang, L. Y.

2018-01-01

Background: Type I x-ray bursts are the most frequently observed thermonuclear explosions in the galaxy, resulting from thermonuclear runaway on the surface of an accreting neutron star. The 30S(α ,p ) reaction plays a critical role in burst models, yet insufficient experimental information is available to calculate a reliable, precise rate for this reaction. Purpose: Our measurement was conducted to search for states in 34Ar and determine their quantum properties. In particular, natural-parity states with large α -decay partial widths should dominate the stellar reaction rate. Method: We performed the first measurement of 30S+α resonant elastic scattering up to a center-of-mass energy of 5.5 MeV using a radioactive ion beam. The experiment utilized a thick gaseous active target system and silicon detector array in inverse kinematics. Results: We obtained an excitation function for 30S(α ,α ) near 150∘ in the center-of-mass frame. The experimental data were analyzed with R -matrix calculations, and we observed three new resonant patterns between 11.1 and 12.1 MeV, extracting their properties of resonance energy, widths, spin, and parity. Conclusions: We calculated the resonant thermonuclear reaction rate of 30S(α ,p ) based on all available experimental data of 34Ar and found an upper limit about one order of magnitude larger than a rate determined using a statistical model. The astrophysical impact of these two rates has been investigated through one-zone postprocessing type I x-ray burst calculations. We find that our new upper limit for the 30S(α ,p )33Cl rate significantly affects the predicted nuclear energy generation rate during the burst.

PLASMA DEVICE

DOEpatents

Baker, W.R.; Brathenahl, A.; Furth, H.P.

1962-04-10

A device for producing a confined high temperature plasma is described. In the device the concave inner surface of an outer annular electrode is disposed concentrically about and facing the convex outer face of an inner annular electrode across which electrodes a high potential is applied to produce an electric field there between. Means is provided to create a magnetic field perpendicular to the electric field and a gas is supplied at reduced pressure in the area therebetween. Upon application of the high potential, the gas between the electrodes is ionized, heated, and under the influence of the electric and magnetic fields there is produced a rotating annular plasma disk. The ionized plasma has high dielectric constant properties. The device is useful as a fast discharge rate capacitor, in controlled thermonuclear research, and other high temperature gas applications. (AEC)

Astrophysics at the future Rare Isotope Accelerator

NASA Astrophysics Data System (ADS)

Smith, Michael; Schatz, Hendrik; Timmes, Frank X.; Wiescher, Michael; Greife, Uwe

PoS(NIC-IX)179 Significant progress in studies of core collapse supernovae, thermonuclear supernovae, X-ray bursts, novae, and other astrophysical phenomena require intense beams of a wide range of unsta- ble nuclei. While some such beams are currently available and being used for important studies in nuclear astrophysics, the beams are often insufficient in intensity, purity, or available isotopes. It is anticipated that a next-generation radioactive beam facility will be built in the U.S. in the next decade to address these shortcomings, and a Working Group has been established to develop and promote nuclear astrophysics research at this new facility. Many of the topics addressed by the Working Group are relevant for the RIKEN RI Beam Factory, the planned GSI-Fair facility, and other advanced radioactive beam facilities around the world.

Alloying of steel and graphite by hydrogen in nuclear reactor

NASA Astrophysics Data System (ADS)

Krasikov, E.

2017-02-01

In traditional power engineering hydrogen may be one of the first primary source of equipment damage. This problem has high actuality for both nuclear and thermonuclear power engineering. Study of radiation-hydrogen embrittlement of the steel raises the question concerning the unknown source of hydrogen in reactors. Later unexpectedly high hydrogen concentrations were detected in irradiated graphite. It is necessary to look for this source of hydrogen especially because hydrogen flakes were detected in reactor vessels of Belgian NPPs. As a possible initial hypothesis about the enigmatical source of hydrogen one can propose protons generation during beta-decay of free neutrons поскольку inasmuch as protons detected by researches at nuclear reactors as witness of beta-decay of free neutrons.

Magnetized target fusion: An ultra high energy approach in an unexplored parameter space

NASA Astrophysics Data System (ADS)

Lindemuth, I. R.

Magnetized target fusion is a concept that may lead to practical fusion applications in a variety of settings. However, the crucial first step is to demonstrate that it works as advertised. Among the possibilities for doing this is an ultrahigh energy approach to magnetized target fusion, one powered by explosive pulsed power generators that have become available for application to thermonuclear fusion research. In a collaborative effort between Los Alamos and the All-Russian Scientific Institute for Experimental Physics (VNIIEF) a very powerful helical generator with explosive power switching has been used to produce an energetic magnetized plasma. Several diagnostics have been fielded to ascertain the properties of this plasma. We are intensively studying the results of the experiments and calculationally analyzing the performance of this experiment.

Dealing With Russian Tactical Nuclear Weapons

DTIC Science & Technology

2004-01-01

the plants, facilities, and equipment necessary to safely secure and store weapons pits (the plutonium “triggers” at the center of a thermonuclear ... bomb , and hence the most critical piece) proffered by either party. Furthermore, the statute requires the IAEA to establish control over the pits until

Controlled Nuclear Fusion.

ERIC Educational Resources Information Center

Glasstone, Samuel

This publication is one of a series of information booklets for the general public published by The United States Atomic Energy Commission. Among the topics discussed are: Importance of Fusion Energy; Conditions for Nuclear Fusion; Thermonuclear Reactions in Plasmas; Plasma Confinement by Magnetic Fields; Experiments With Plasmas; High-Temperature…

CuPb rheocast alloy as joining material for CFC composites

NASA Astrophysics Data System (ADS)

Salvo, M.; Lemoine, P.; Ferraris, M.; Appendino Montorsi, M.; Matera, R.

1995-10-01

High heat flux components for future use in thermonuclear fusion reactors are designed as layered structures. The assembling of the different parts (armour, heat sink and external structure) requires a joint which could withstand large heat loads and thermal stresses. In this paper we examined a 50 wt% PbCu rheocast alloy (RCA) as joining material for the armour/heat sink joint. The alloy was prepared in vacuum in a rotational furnace and was characterized by SEM-EDS analysis and heating microscopy. The obtained microstructure was globular as foreseen and it remained after prolonged heating at 650°C. The alloy showed very good ductility: sheets of about 200 μm were rolled starting from about 1 × 1 × 1 cm 3 cubes. The alloy was successful in joining both the armour and the heat sink materials, respectively, carbon fibre reinforced composites and copper. Initial mechanical testing shows that the technique is viable for the foreseen applications in the field of thermonuclear fusion reactors.

Determination of deuterium–tritium critical burn-up parameter by four temperature theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nazirzadeh, M.; Ghasemizad, A.; Khanbabei, B.

Conditions for thermonuclear burn-up of an equimolar mixture of deuterium-tritium in non-equilibrium plasma have been investigated by four temperature theory. The photon distribution shape significantly affects the nature of thermonuclear burn. In three temperature model, the photon distribution is Planckian but in four temperature theory the photon distribution has a pure Planck form below a certain cut-off energy and then for photon energy above this cut-off energy makes a transition to Bose-Einstein distribution with a finite chemical potential. The objective was to develop four temperature theory in a plasma to calculate the critical burn up parameter which depends upon initialmore » density, the plasma components initial temperatures, and hot spot size. All the obtained results from four temperature theory model are compared with 3 temperature model. It is shown that the values of critical burn-up parameter calculated by four temperature theory are smaller than those of three temperature model.« less

Thermonuclear dynamo inside ultracentrifuge with supersonic plasma flow stabilization

NASA Astrophysics Data System (ADS)

Winterberg, F.

2016-01-01

Einstein's general theory of relativity implies the existence of virtual negative masses in the rotational reference frame of an ultracentrifuge with the negative mass density of the same order of magnitude as the positive mass density of a neutron star. In an ultracentrifuge, the repulsive gravitational field of this negative mass can simulate the attractive positive mass of a mini-neutron star, and for this reason can radially confine a dense thermonuclear plasma placed inside the centrifuge, very much as the positive mass of a star confines its plasma by its own attractive gravitational field. If the centrifuge is placed in an externally magnetic field to act as the seed field of a magnetohydrodynamic generator, the configuration resembles a magnetar driven by the release of energy through nuclear fusion, accelerating the plasma to supersonic velocities, with the magnetic field produced by the thermomagnetic Nernst effect insulating the hot plasma from the cold wall of the centrifuge. Because of the supersonic flow and the high plasma density the configuration is stable.

Efficiency of Tungsten Dust Collection of Different Types of Dust Particles by Electrostatic Probe

NASA Astrophysics Data System (ADS)

Begrambekov, L. B.; Voityuk, A. N.; Zakharov, A. M.; Bidlevich, O. A.; Vechshev, E. A.; Shigin, P. A.; Vayakis, J.; Walsh, M.

2017-12-01

Formation of dust particles and clusters is observed in almost every modern thermonuclear facility. Accumulation of dust in the next generation thermonuclear installations can dramatically affect the plasma parameters and lead to the accumulation of unacceptably large amounts of tritium. Experiments on collection of dust particles by a model of electrostatic probe developed for collection of metallic dust at ITER are described in the article. Experiments on the generation of tungsten dust consisting of flakes formed during the destruction of tungsten layers formed on the walls of the plasma chamber sputtered from the surface of the tungsten target by plasma ions were conducted. The nature of dust degassing at elevated temperatures and the behavior of dust in an electric field were studied. The results obtained are compared with the results of the experiments with dust consisting of crystal particles of simple geometric shapes. The effectiveness of collection of both types of dust using the model of an electrostatic probe is determined.

On the Theory of Type 1 X-Ray Bursts: The Energetics of Bursts and the Nuclear Fuel Reservoir in the Envelope

NASA Technical Reports Server (NTRS)

Fujimoto, Masayuki Y.; Sztajno, Mirek; Lewin, Walter H. G.; Vanparadijs, Jan

1986-01-01

The observed properties of type 1 X-ray bursts from 4U/MXB 1636-53 and those of models of thermonuclear flashes on accreting neutron stars are compared. Ways to explain variations in the burst recurrence properties without an apparent correlation with the accretion rate, including the rapid succession of bursts at intervals 10 min are discussed. The strongest X-ray bursts, which occur after a very long interval, are well described by thermonuclear flash models with simple accumulation of accreted fuel, and a spherically symmetric structure in the burning shell. The majority of observed bursts, however, occur after much shorter intervals, and radiate much smaller amounts of energy, by a factor of up to 10 times that predicted by the spherical models. An ignition mechanism of the bursts is proposed in terms of elemental mixing and dissipative heating associated with hydrodynamical instabilities in the neutron star envelope caused by angular momentum carried inward by accreted gas.

Neutron Generation by Laser-Driven Spherically Convergent Plasma Fusion.

PubMed

Ren, G; Yan, J; Liu, J; Lan, K; Chen, Y H; Huo, W Y; Fan, Z; Zhang, X; Zheng, J; Chen, Z; Jiang, W; Chen, L; Tang, Q; Yuan, Z; Wang, F; Jiang, S; Ding, Y; Zhang, W; He, X T

2017-04-21

We investigate a new laser-driven spherically convergent plasma fusion scheme (SCPF) that can produce thermonuclear neutrons stably and efficiently. In the SCPF scheme, laser beams of nanosecond pulse duration and 10^{14}-10^{15}  W/cm^{2} intensity uniformly irradiate the fuel layer lined inside a spherical hohlraum. The fuel layer is ablated and heated to expand inwards. Eventually, the hot fuel plasmas converge, collide, merge, and stagnate at the central region, converting most of their kinetic energy to internal energy, forming a thermonuclear fusion fireball. With the assumptions of steady ablation and adiabatic expansion, we theoretically predict the neutron yield Y_{n} to be related to the laser energy E_{L}, the hohlraum radius R_{h}, and the pulse duration τ through a scaling law of Y_{n}∝(E_{L}/R_{h}^{1.2}τ^{0.2})^{2.5}. We have done experiments at the ShengGuangIII-prototype facility to demonstrate the principle of the SCPF scheme. Some important implications are discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Casey, D. T.; Sayre, D. B.; Brune, C. R.

Stars are giant thermonuclear plasma furnaces that slowly fuse the lighter elements in the universe into heavier elements, releasing energy, and generating the pressure required to prevent collapse. To understand stars, we must rely on nuclear reaction rate data obtained, up to now, under conditions very different from those of stellar cores. Here we show thermonuclear measurements of the 2H(d, n) 3He and 3H(t,2n) 4He S-factors at a range of densities (1.2–16 g cm –3) and temperatures (2.1–5.4 keV) that allow us to test the conditions of the hydrogen-burning phase of main-sequence stars. The relevant conditions are created using inertial-confinementmore » fusion implosions at the National Ignition Facility. Here, our data agree within uncertainty with previous accelerator-based measurements and establish this approach for future experiments to measure other reactions and to test plasma-nuclear effects present in stellar interiors, such as plasma electron screening, directly in the environments where they occur.« less

Neutron Generation by Laser-Driven Spherically Convergent Plasma Fusion

NASA Astrophysics Data System (ADS)

Ren, G.; Yan, J.; Liu, J.; Lan, K.; Chen, Y. H.; Huo, W. Y.; Fan, Z.; Zhang, X.; Zheng, J.; Chen, Z.; Jiang, W.; Chen, L.; Tang, Q.; Yuan, Z.; Wang, F.; Jiang, S.; Ding, Y.; Zhang, W.; He, X. T.

2017-04-01

We investigate a new laser-driven spherically convergent plasma fusion scheme (SCPF) that can produce thermonuclear neutrons stably and efficiently. In the SCPF scheme, laser beams of nanosecond pulse duration and 1 014- 1 015 W /cm2 intensity uniformly irradiate the fuel layer lined inside a spherical hohlraum. The fuel layer is ablated and heated to expand inwards. Eventually, the hot fuel plasmas converge, collide, merge, and stagnate at the central region, converting most of their kinetic energy to internal energy, forming a thermonuclear fusion fireball. With the assumptions of steady ablation and adiabatic expansion, we theoretically predict the neutron yield Yn to be related to the laser energy EL, the hohlraum radius Rh, and the pulse duration τ through a scaling law of Yn∝(EL/Rh1.2τ0.2 )2.5. We have done experiments at the ShengGuangIII-prototype facility to demonstrate the principle of the SCPF scheme. Some important implications are discussed.

Frequent bursts from the 11 Hz transient pulsar IGR J17480-2446

NASA Astrophysics Data System (ADS)

Chakraborty, Manoneeta; Mukherjee, Arunava; Bhattacharyya, S.

Accreted matter falling on the surface of the neutron star in a Low Mass X-ray Binary (LMXB) system gives rise to intense X-ray bursts originating from unstable thermonuclear conflagration and these bursts can be used as a tool to constrain the equation of state. A series of such X-ray bursts along with millihertz (mHz) quasi-periodic oscillations (QPOs) at the highest source luminosities were observed during the 2010 outburst of the transient LMXB pulsar IGR J17480--2446. The quite diverse burst properties compared to typical type-I bursts suggested them to be the type-II bursts originating from accretion disc instability. We show that the bursts are indeed of thermonuclear origin and thus confirm the quasi-stable burning model for mHz QPOs. Various properties of the bursts such as, peak flux, fluence, periodicity and duration, were highly dependent on the source spectral states and their variation over a large accretion rate range revealed the evolution of the burning process at different accretion rate regimes.

Focused Study of Thermonuclear Bursts on Neutron Stars

NASA Astrophysics Data System (ADS)

Chenevez, Jérôme

2009-05-01

X-ray bursters form a class of Low Mass X-Ray Binaries where accreted material from a donor star undergoes rapid thermonuclear burning in the surface layers of a neutron star. The flux released can temporarily exceed the Eddington limit and drive the photosphere to large radii. Such photospheric radius expansion bursts likely eject nuclear burning ashes into the interstellar medium, and may make possible the detection of photoionization edges. Indeed, theoretical models predict that absorption edges from 58Fe at 9.2 keV, 60Zn and 62Zn at 12.2 keV should be detectable by the future missions Simbol-X and NuSTAR. A positive detection would thus probe the nuclear burning as well as the gravitational redshift from the neutron star. Moreover, likely observations of atomic X-ray spectral components reflected from the inner accretion disk have been reported. The high spectral resolution capabilities of the focusing X-ray telescopes may therefore make possible to differentiate between the potential interpretations of the X-ray bursts spectral features.

Alternative disposal options for transuranic waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loomis, G.G.

1994-12-31

Three alternative concepts are proposed for the final disposal of stored and retrieved buried transuranic waste. These proposed options answer criticisms of the existing U.S. Department of Energy strategy of directly disposing of stored transuranic waste in deep, geological salt formations at the Waste Isolation Pilot Plant (WIPP) in Carlsbad, New Mexico. The first option involves enhanced stabilization of stored waste by thermal treatment followed by convoy transportation and internment in the existing WIPP facility. This concept could also be extended to retrieved buried waste with proper permitting. The second option involves in-state, in situ internment using an encapsulating lensmore » around the waste. This concept applies only to previously buried transuranic waste. The third option involves sending stored and retrieved waste to the Nevada Test Site and configuring the waste around a thermonuclear device from the U.S. or Russian arsenal in a specially designed underground chamber. The thermonuclear explosion would transmute plutonium and disassociate hazardous materials while entombing the waste in a national sacrifice area.« less

Tokamak foundation in USSR/Russia 1950-1990

NASA Astrophysics Data System (ADS)

Smirnov, V. P.

2010-01-01

In the USSR, nuclear fusion research began in 1950 with the work of I.E. Tamm, A.D. Sakharov and colleagues. They formulated the principles of magnetic confinement of high temperature plasmas, that would allow the development of a thermonuclear reactor. Following this, experimental research on plasma initiation and heating in toroidal systems began in 1951 at the Kurchatov Institute. From the very first devices with vessels made of glass, porcelain or metal with insulating inserts, work progressed to the operation of the first tokamak, T-1, in 1958. More machines followed and the first international collaboration in nuclear fusion, on the T-3 tokamak, established the tokamak as a promising option for magnetic confinement. Experiments continued and specialized machines were developed to test separately improvements to the tokamak concept needed for the production of energy. At the same time, research into plasma physics and tokamak theory was being undertaken which provides the basis for modern theoretical work. Since then, the tokamak concept has been refined by a world-wide effort and today we look forward to the successful operation of ITER.

Development of a cryogenic load frame for the neutron diffractometer at Takumi in Japan Proton Accelerator Research Complex

NASA Astrophysics Data System (ADS)

Jin, Xinzhe; Nakamoto, Tatsushi; Harjo, Stefanus; Hemmi, Tsutomu; Umeno, Takahiro; Ogitsu, Toru; Yamamoto, Akira; Sugano, Michinaka; Aizawa, Kazuya; Abe, Jun; Gong, Wu; Iwahashi, Takaaki

2013-06-01

To prepare for projects such as the Large Hadron Collider upgrade, International Thermonuclear Experimental Reactor and Demonstration reactor, it is important to form a clear understanding of stress-strain properties of the materials that make up superconducting magnets. Thus, we have been studying the mechanical properties of superconducting wires using neutron diffraction measurements. To simulate operational conditions such as temperature, stress, and strain, we developed a cryogenic load frame for stress-strain measurements of materials using a neutron diffractometer at Japan Proton Accelerator Research Complex (J-PARC) Takumi beam line. The maximum load that can be applied to a sample using an external driving machine is 50 kN. Using a Gifford-MacMahon cryocooler, samples can be measured down to temperatures below 10 K when loaded. In the present paper, we describe the details of the cryogenic load frame with its test results by using type-304 stainless steel wire.

Development of a cryogenic load frame for the neutron diffractometer at Takumi in Japan Proton Accelerator Research Complex

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Xinzhe; Nakamoto, Tatsushi; Ogitsu, Toru

2013-06-15

To prepare for projects such as the Large Hadron Collider upgrade, International Thermonuclear Experimental Reactor and Demonstration reactor, it is important to form a clear understanding of stress-strain properties of the materials that make up superconducting magnets. Thus, we have been studying the mechanical properties of superconducting wires using neutron diffraction measurements. To simulate operational conditions such as temperature, stress, and strain, we developed a cryogenic load frame for stress-strain measurements of materials using a neutron diffractometer at Japan Proton Accelerator Research Complex (J-PARC) Takumi beam line. The maximum load that can be applied to a sample using an externalmore » driving machine is 50 kN. Using a Gifford-MacMahon cryocooler, samples can be measured down to temperatures below 10 K when loaded. In the present paper, we describe the details of the cryogenic load frame with its test results by using type-304 stainless steel wire.« less

Development of a cryogenic load frame for the neutron diffractometer at Takumi in Japan Proton Accelerator Research Complex.

PubMed

Jin, Xinzhe; Nakamoto, Tatsushi; Harjo, Stefanus; Hemmi, Tsutomu; Umeno, Takahiro; Ogitsu, Toru; Yamamoto, Akira; Sugano, Michinaka; Aizawa, Kazuya; Abe, Jun; Gong, Wu; Iwahashi, Takaaki

2013-06-01

To prepare for projects such as the Large Hadron Collider upgrade, International Thermonuclear Experimental Reactor and Demonstration reactor, it is important to form a clear understanding of stress-strain properties of the materials that make up superconducting magnets. Thus, we have been studying the mechanical properties of superconducting wires using neutron diffraction measurements. To simulate operational conditions such as temperature, stress, and strain, we developed a cryogenic load frame for stress-strain measurements of materials using a neutron diffractometer at Japan Proton Accelerator Research Complex (J-PARC) Takumi beam line. The maximum load that can be applied to a sample using an external driving machine is 50 kN. Using a Gifford-MacMahon cryocooler, samples can be measured down to temperatures below 10 K when loaded. In the present paper, we describe the details of the cryogenic load frame with its test results by using type-304 stainless steel wire.

Evolution of Supernova Remnants

NASA Astrophysics Data System (ADS)

Arbutina, B.

2017-12-01

This book, both a monograph and a graduate textbook, is based on my original research and partly on the materials prepared earlier for the 2007 and 2008 IARS Astrophysics Summer School in Istanbul, AstroMundus course 'Supernovae and Their Remnants' that was held for the first time in 2011 at the Department of Astronomy, Faculty of Mathematics, University of Belgrade, and a graduate course 'Evolution of Supernova Remnants' that I teach at the aforementioned university. The first part Supernovae (introduction, thermonuclear supernovae, core-collapse supernovae) provides introductory information and explains the classification and physics of supernova explosions, while the second part Supernova remnants (introduction, shock waves, cosmic rays and particle acceleration, magnetic fields, synchrotron radiation, hydrodynamic and radio evolution of supernova remnants), which is the field I work in, is more detailed in scope i.e. technical/mathematical. Special attention is paid to details of mathematical derivations that often cannot be found in original works or available literature. Therefore, I believe it can be useful to both, graduate students and researchers interested in the field.

FROM THE HISTORY OF PHYSICS: American and Soviet H-bomb development programmes: historical background

NASA Astrophysics Data System (ADS)

Goncharov, German A.

1996-10-01

The genesis and historical background of the hydrogen bomb are described, with particular emphasis placed on the development of the physical ideas which led to the discovery of the basic principle of thermonuclear charge construction in the USA and USSR.

Iodine Systematics in the Ground Water of a Natural Setting

NASA Astrophysics Data System (ADS)

Renaud, R.; Clark, I. D.; Kotzer, T.; Bottomley, D.

2001-12-01

The transport and partitioning of 129I has been examined for a shallowly circulating ground water system at Sturgeon Falls in eastern Ontario. Vertical recharge occurs in a sandy aquifer with a seasonally inundated boreal forest. Concentrations of stable iodine, 129I, and tritium were measured on samples of ground water, precipitation, and soil litter. The present-day tritium profile delineates the position of the early 1960's thermonuclear bomb-pulse at a depth approximately 12 m. The concentrations of stable iodine for ground waters above, near and below the present-day bomb pulse were largely invariant, at approximately 0.5 ppb, whereas 129I concentrations decreased from 1.9 x 106 atoms/L at 9 m, to approximately 1.9 x 105 atoms/L on tritium-depleted waters occurring below the present-day location of the recharging thermonuclear bomb-test peak at 35 m. No substantial increases in the levels of 129I were evident in waters sampled near the present-day location of the thermonuclear bomb peak. Along a 30 cm soil profile, the concentrations of 129I ranged from approximately 4.3 x 108 atoms/g in the uppermost soil litter layer to 5.6 x 107 atoms/g in the siltier bottom soil horizons. Over that same profile, stable iodine varied from 4.7 ppm in the upper layers to 3.9 ppm in the lower layers. Rao and Fehn, 1999, measured iodine and 129I levels in surface waters and soils in western New York. They found 129I concentrations ranging from 3.5 x 108 atoms/g to 7.1 x 1010 atoms/g in the upper most layers of their soil cores, depending on the site's proximity to a former nuclear fuel reprocessing plant. Similarly, they noticed that the lower layers of their soil cores had 129I concentrations of at least an order of magnitude lower than the upper layers. It is proposed here that the levels of 129I in the deepest, tritium-depleted ground waters reflect the concentrations of 129I during the pre-thermonuclear testing period. However, the lower concentrations of 129I at Sturgeon Falls, compared with those from other studies in central Canada, suggest that the levels of 129I in these ground waters may have been attenuated by ion-exchange with organic materials in the near-surface soil horizons. Such processes have been documented during a previous study on the behavior of 129I in a shallow aquifer near a low-level, radioactive waste management area.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kilkenny, J.; Richau, G.; Sangster, C.

A major goal of the Stockpile Stewardship Program (SSP) is to deliver validated numerical models, benchmarked against experiments that address relevant and important issues and provide data that stress the codes and our understanding. DOENNSA has made significant investments in major facilities and high-performance computing to successfully execute the SSP. The more information obtained about the physical state of the plasmas produced, the more stringent the test of theories, models, and codes can be, leading to increased confidence in our predictive capability. To fully exploit the world-leading capabilities of the ICF program, a multi-year program to develop and deploy advancedmore » diagnostics has been developed by the expert scientific community. To formalize these activities NNSA’s Acting Director for the Inertial Confinement Fusion Program directed the formation and duties of the National Diagnostics Working Group (NDWG) in a Memorandum 11/3/16 (Appendix A). The NDWG identified eight transformational diagnostics, shown in Table 1, that will provide unprecedented information from experiments in support of the SSP at NIF, Z and OMEGA. Table 1 shows how the missions of the SSP experiments including materials, complex hydrodynamics, radiation flow and effects and thermo-nuclear burn and boost will produce new observables, which will be measured using a variety of largely new diagnostic technologies used in the eight transformational diagnostics. The data provided by these diagnostics will validate and improve the physics contained within the SSP’s simulations and both uncover and quantify important phenomena that lie beyond our present understanding.« less

Radiation effects and tritium technology for fusion reactors. Volume I. Proceedings of the international conference, Gatlinburg, Tennessee, October 1--3, 1975

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watson, J.S.; Wiffen, F.W.; Bishop, J.L.

1976-03-01

Separate abstracts were prepared for the 29 included papers in Vol. I. The topics covered in this volume include swelling and microstructures in thermonuclear reactor materials. Some papers on modeling and damage analysis are included. (MOW)

Computational Astrophysics Consortium, University of Minnesota, Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heger, Alexander

During its six year duration the Computational Astrophysics consortium helped to train the next generation of scientists in computational and nuclear astrophysics. A total of five graduate students were supported by the grant at UMN. The major advances at UMN were in the use, testing, and contribution to development of the CASTRO that efficiently scales on over 100,000 CPUs. At UMN it was used for modeling of thermonuclear supernovae (pair instability and supermassive stars) and core-collapse supernovae as well as the final phases of their progenitors, as well as for x-ray bursts from accreting neutron stars. Important secondary advances inmore » the field of nuclear astrophysics included a better understanding of the evolution of massive stars and the origin of the elements. The research resulted in more than 50 publications.« less

Three dimensional calculation of thermonuclear ignition conditions for magnetized targets

NASA Astrophysics Data System (ADS)

Cortez, Ross; Cassibry, Jason; Lapointe, Michael; Adams, Robert

2017-10-01

Fusion power balance calculations, often performed using analytic methods, are used to estimate the design space for ignition conditions. In this paper, fusion power balance is calculated utilizing a 3-D smoothed particle hydrodynamics code (SPFMax) incorporating recent stopping power routines. Effects of thermal conduction, multigroup radiation emission and nonlocal absorption, ion/electron thermal equilibration, and compressional work are studied as a function of target and liner parameters and geometry for D-T, D-D, and 6LI-D fuels to identify the potential ignition design space. Here, ignition is defined as the condition when fusion particle deposition equals or exceeds the losses from heat conduction and radiation. The simulations are in support of ongoing research with NASA to develop advanced propulsion systems for rapid interplanetary space travel. Supported by NASA Innovative Advanced Concepts and NASA Marshall Space Flight Center.

Optimizing pulse shaping and zooming for acceleration to high velocities and fusion neutron production on the Nike laser

NASA Astrophysics Data System (ADS)

Karasik, Max; Weaver, J. L.; Aglitskiy, Y.; Zalesak, S. T.; Velikovich, A. L.; Oh, J.; Obenschain, S. P.; Arikawa, Y.; Watari, T.

2010-11-01

We will present results from follow-on experiments to the record-high velocities of 1000 km/s achieved on Nike [Karasik et al., Phys. Plasmas 17, 056317 (2010) ], in which highly accelerated planar foils of deuterated polystyrene were made to collide with a witness foil to produce extreme shock pressures and result in heating of matter to thermonuclear temperatures. Still higher velocities and higher target densities are required for impact fast ignition. The aim of these experiments is shaping the driving pulse to minimize shock heating of the accelerated target and using the focal zoom capability of Nike to achieve higher densities and velocities. Spectroscopic measurements of electron temperature achieved upon impact will complement the neutron time-of-flight ion temperature measurement. Work is supported by US DOE and Office of Naval Research.

Firework Nova

NASA Image and Video Library

2015-07-02

In Hollywood blockbusters, explosions are often among the stars of the show. In space, explosions of actual stars are a focus for scientists who hope to better understand their births, lives, and deaths and how they interact with their surroundings. Using NASA’s Chandra X-ray Observatory, astronomers have studied one particular explosion that may provide clues to the dynamics of other, much larger stellar eruptions. A team of researchers pointed the telescope at GK Persei, an object that became a sensation in the astronomical world in 1901 when it suddenly appeared as one of the brightest stars in the sky for a few days, before gradually fading away in brightness. Today, astronomers cite GK Persei as an example of a “classical nova,” an outburst produced by a thermonuclear explosion on the surface of a white dwarf star, the dense remnant of a Sun-like star.

Exploring Systematic Effects in Thermonuclear Supernovae

NASA Astrophysics Data System (ADS)

Jackson, Aaron Perry

Type Ia supernovae (SNe) are bright astrophysical explosions that form a remarkably homogeneous class of objects serving as the premier distance indicators for studying the expansion history of the Universe and the nature of dark energy. Despite the widespread acceptance of the surprising discovery of the acceleration of the expansion of the Universe and the existence of the mysterious dark energy driving it that followed from these studies, the progenitor systems of these explosions are unknown. Knowledge of the progenitor system is required to understand possible systematic effects due to properties of the parent stellar population or host galaxy. While several scenarios have been proposed, the most widely accepted one is the thermonuclear explosion of a near-Chandrasekharmass, carbon-oxygen white dwarf (WD). Under this scenario, the explosive burning begins near the center as a deflagration (subsonic burning) that transitions to a detonation (supersonic burning) some time later after the WD has expanded in response to the energy release. Turbulence, either pre-existing or generated by burning, serves to increase the surface area of the burning front, thus enhancing the fuel consumption rate. In addition, turbulence--flame interaction (TFI) may be responsible for deflagration--detonation transition (DDT). Simulations of this explosion scenario typically parameterize the DDT to occur when the flame reaches a particular density. I performed a suite of two-dimensional (2D) simulations with the compressible, hydrodynamics code FLASH to evaluate the influence of the DDT density on the average yield of radioactive 56Ni that powers the SN light curve. In addition, I considered the compositional dependence of the DDT density to explore one way in which metallicity may influence the explosion outcome. My results have confirmed a new pathway to explain observed trends in the average peak brightness of SNe Ia with host galaxy metallicity. In a separate study, I address the basic physics of modeling flames and turbulent combustion. The disparate length scales in the SN necessitate use of a flame model to capture the effect of burning on unresolved scales. I implemented a method to measure the strength of unresolved turbulence, which is used to estimate the amount of wrinkling of the unresolved flame surface. In addition, the measure of turbulent strength may be used to improve the criterion by which DDT is initiated. These improvements will allow three-dimensional (3D) simulations of the early flame evolution in the presence of strong pre-existing turbulence. The research conducted for this dissertation has led to important insights into the explosion mechanism of SNe Ia. In addition, improvements to the model have allowed and will continue to allow simulations of unprecedented realism of the complex process of exploding WDs in a thermonuclear SN.

Physics design of the injector source for ITER neutral beam injector (invited).

PubMed

Antoni, V; Agostinetti, P; Aprile, D; Cavenago, M; Chitarin, G; Fonnesu, N; Marconato, N; Pilan, N; Sartori, E; Serianni, G; Veltri, P

2014-02-01

Two Neutral Beam Injectors (NBI) are foreseen to provide a substantial fraction of the heating power necessary to ignite thermonuclear fusion reactions in ITER. The development of the NBI system at unprecedented parameters (40 A of negative ion current accelerated up to 1 MV) requires the realization of a full scale prototype, to be tested and optimized at the Test Facility under construction in Padova (Italy). The beam source is the key component of the system and the design of the multi-grid accelerator is the goal of a multi-national collaborative effort. In particular, beam steering is a challenging aspect, being a tradeoff between requirements of the optics and real grids with finite thickness and thermo-mechanical constraints due to the cooling needs and the presence of permanent magnets. In the paper, a review of the accelerator physics and an overview of the whole R&D physics program aimed to the development of the injector source are presented.

Plasma kinetic effects on atomistic mix in one dimension and at structured interfaces (II)

NASA Astrophysics Data System (ADS)

Albright, Brian; Yin, Lin; Cooley, James; Haack, Jeffrey; Douglas, Melissa

2017-10-01

The Marble campaign seeks to develop a platform for studying mix evolution in turbulent, inhomogeneous, high-energy-density plasmas at the NIF. Marble capsules contain engineered CD foams, the pores of which are filled with hydrogen and tritium. During implosion, hydrodynamic stirring and plasma diffusivity mix tritium fuel into the surrounding CD plasma, leading to both DD and DT fusion neutron production. In this presentation, building upon prior work, kinetic particle-in-cell simulations using the VPIC code are used to examine kinetic effects on thermonuclear burn in Marble-like settings. Departures from Maxwellian distributions are observed near the interface and TN burn rates and inferred temperatures from synthetic neutron time of flight diagnostics are compared with those from treating the background species as Maxwellian. Work performed under the auspices of the U.S. DOE by the Los Alamos National Security, LLC Los Alamos National Laboratory and supported by the ASC and Science programs.

Final Technical Report for Award DE-FG02-98ER41080

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Alan

The prime motivation of the project at McMaster University was to carry out the critical evaluation and compilation of Nuclear Structure and Decay data, and of nuclear astrophysics data with continued participation in the United States Nuclear Data Program (US-NDP). A large body of evaluated and compiled structure data were supplied for databases such as ENSDF, XUNDL, NSR, etc. residing on webpage of National Nuclear Data Center of the Brookhaven National Laboratory, Upton, New York, USA. Thermonuclear reaction rates of importance to stellar explosions, such as novae, x-ray bursts and supernovae, were evaluated as well. This effort was closely coupledmore » to our ongoing experimental effort, which took advantage of radioactive ion beam and stable beam facilities worldwide to study these key reaction rates. This report contains brief descriptions of the various activities together with references to all the publications in peer-reviewed journals which were the result of work carried out with the award DE-FG02-98-ER41080, during 1998-2013.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boyer, W.H.

The last several centuries have led humanity to believe that each succeeding generation can expect to live better than did the previous generation. But this is no longer true, and, to survive, the human species must successfully face four impending crises: overpopulation, the destruction of the biosphere, the end of cheap and available energy, and the threat of thermonuclear holocaust.

JONAH algorithms: C-2 the ratio option

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rego, J.

1979-02-01

Information concerning input is given first. Then formulas are given for calculation of atoms/millimeter, fissions, kiloton yield, R-value, atoms/fission, fissions/fission, bomb fraction, fissions/atoms, atoms, atoms/atoms, fissions/atoms, atom ratio, total atoms formed, and thermonuclear bomb fraction. Some of the terminology used is elucidated in an appendix. (RWR)

Type I X-Ray Bursts at Low Accretion Rates

NASA Astrophysics Data System (ADS)

Peng, Fang; Brown, E. F.; Truran, J. W.

2006-06-01

Neutron stars, with their strong surface gravity, have interestingly short timescales for the sedimentation of heavy elements. Recent observations of unstable thermonuclear burning (observed as X-ray bursts) on the surfaces of slowly accreting neutron stars (< 0.01 of the Eddington rate) motivate us to examine how sedimentation of CNO isotopes affects the ignition of these bursts. For neutron stars accreting at rates less than 0.1 Eddington, there is sufficient time for CNO to settle out of the accreted envelope. We estimate the burst development using a simple one-zone model with a full reaction network. At the lowest accretion rates, 0.1 Eddington, there can still be an effect. We note that the reduced proton-to-seed ratio favors the production of 12C--an important ingredient for subsequent superbursts.This work is supported by the U.S. DOE under grant B523820 to the Center for Astrophysical Thermonuclear Flashes at the University of Chicago, JINA under NSF-PFC grant PHY 02-16783, NSF under grant AST-0507456 and U.S. DOE under contract No. W-31-109-ENG-38.

Nucleosynthesis during a Thermonuclear Supernova Explosion

NASA Astrophysics Data System (ADS)

Panov, I. V.; Glazyrin, S. I.; Röpke, F. K.; Blinnikov, S. I.

2018-05-01

Supernovae are such bright objects that they can be observed even at high redshifts. Some types of such events, for example, type Ia (thermonuclear), have peculiarities of the light curve, which allows them to be used for cosmological applications. The light curve is determined by the details of the explosion dynamics and nucleosynthesis: in particular, it depends on the amount of iron-peak elements produced during the explosion. We discuss the burning processes in such objects and the peculiarities of turbulence simulations in them, which is needed for a proper hydrodynamic description of the explosion process. A direct nucleosynthesis calculation is performed for the temperature and density profiles derived in the available 3D hydrodynamic explosion simulations. We show that in the supernova progenitor model considered the calculated abundances of elements from carbon to iron-peak elements are in good agreement both with the observations and with the calculations of other authors. At the same time, no r-elements are produced even at the maximum neutron excess for this model ( Y e 0.47) due to the slow evolution of the density and temperature.

Tidal double detonation: a new mechanism for the thermonuclear explosion of a white dwarf induced by a tidal disruption event

NASA Astrophysics Data System (ADS)

Tanikawa, Ataru

2018-03-01

We suggest tidal double detonation as a new mechanism for the thermonuclear explosion of a white dwarf (WD) induced by a tidal disruption event (TDE). Tidal detonation is also a WD explosion induced by a TDE. In this case, helium (He) and carbon-oxygen (CO) detonation waves incinerate He WDs and CO WDs, respectively. On the other hand, for tidal double detonation, He detonation is first excited in the He shell of a CO WD, which then drives CO detonation in the CO core. We name this mechanism after the double detonation scenario in the context of type Ia supernovae. In this paper, by performing numerical simulations for CO WDs of mass 0.60 M⊙ with and without a He shell, we show that tidal double detonation occurs in the shallower encounter of a CO WD with an intermediate-mass black hole (IMBH) compared to simple tidal detonation. We expect tidal double detonation will increase the possibility of the occurrence of WD TDEs, which can help us to understand IMBHs.

Thermonuclear Bursts with Short Recurrence Times from Neutron Stars Explained by Opacity-driven Convection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keek, L.; Heger, A., E-mail: laurens.keek@nasa.gov

Thermonuclear flashes of hydrogen and helium accreted onto neutron stars produce the frequently observed Type I X-ray bursts. It is the current paradigm that almost all material burns in a burst, after which it takes hours to accumulate fresh fuel for the next burst. In rare cases, however, bursts are observed with recurrence times as short as minutes. We present the first one-dimensional multi-zone simulations that reproduce this phenomenon. Bursts that ignite in a relatively hot neutron star envelope leave a substantial fraction of the fuel unburned at shallow depths. In the wake of the burst, convective mixing events drivenmore » by opacity bring this fuel down to the ignition depth on the observed timescale of minutes. There, unburned hydrogen mixes with the metal-rich ashes, igniting to produce a subsequent burst. We find burst pairs and triplets, similar to the observed instances. Our simulations reproduce the observed fraction of bursts with short waiting times of ∼30%, and demonstrate that short recurrence time bursts are typically less bright and of shorter duration.« less

BAYESIAN ESTIMATION OF THERMONUCLEAR REACTION RATES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iliadis, C.; Anderson, K. S.; Coc, A.

The problem of estimating non-resonant astrophysical S -factors and thermonuclear reaction rates, based on measured nuclear cross sections, is of major interest for nuclear energy generation, neutrino physics, and element synthesis. Many different methods have been applied to this problem in the past, almost all of them based on traditional statistics. Bayesian methods, on the other hand, are now in widespread use in the physical sciences. In astronomy, for example, Bayesian statistics is applied to the observation of extrasolar planets, gravitational waves, and Type Ia supernovae. However, nuclear physics, in particular, has been slow to adopt Bayesian methods. We presentmore » astrophysical S -factors and reaction rates based on Bayesian statistics. We develop a framework that incorporates robust parameter estimation, systematic effects, and non-Gaussian uncertainties in a consistent manner. The method is applied to the reactions d(p, γ ){sup 3}He, {sup 3}He({sup 3}He,2p){sup 4}He, and {sup 3}He( α , γ ){sup 7}Be, important for deuterium burning, solar neutrinos, and Big Bang nucleosynthesis.« less

Tridimensional Thermonuclear Instability in Subignited Plasmas and on the Surface of the Pulsars

NASA Astrophysics Data System (ADS)

Cardinali, A.; Coppi, B.

2017-10-01

Tridimensional modes involving an increase of the electron temperature can be excited as a result of alpha-particle heating in subignited D-T fusion burning plasmas when a nearly time- independent external source of heating is applied. The analyzed modes are shown to emerge from an axisymmetric toroidal configurations and are radially localized around rational magnetic surfaces corresponding to q(r =r0) =m0 /n0 where m0 and n0 are the relevant poloidal and toroidal mode numbers. The radial width of the mode is of the order of the thermal scale distance. The mode has a rather severe damping rate, that has to be overcome by the relevant heating rate. Thus the temperature range to be considered is that where the D-T plasma reactivity undergoes a relatively large increase as a function of temperature. This kind of theory has been applied to the plasmas that are envisioned to be associated with surface of pulsar and be subjects to (spatially) inhomogenous thermonuclear burning. Sponsored in part by the U.S. DoE.

Magnetic booster fast ignition macron accelerator

NASA Astrophysics Data System (ADS)

Winterberg, F.

2006-11-01

A new fast ignition scheme was recently proposed where the ignition is done by the impact of a small solid projectile accelerated to velocities in excess of 108cm/s, with the acceleration done in two steps: first, by laser ablation of a flyer plate, and second by injecting the flyer plate into a conical duct. The two principal difficulties of this scheme are as follows: first, the required large mass ratio for the laser ablation rocket propelled flyer plate, and second, the Rayleigh-Taylor instability of the flyer plate during its implosive compression in the conical duct. To overcome these difficulties, it is suggested to accelerate a projectile by a magnetic fusion booster stage, made up of a dense, wall-confined magnetized plasma brought to thermonuclear temperatures. After ignition, this plasma undergoes a thermonuclear excursion greatly increasing its pressure, resulting in the explosion of a weakened segment of the wall, with the segment becoming a fast moving projectile. The maximum velocity this projectile can reach is the velocity of sound of the booster stage plasma, which at a temperature of 108K is of the order 108cm/s.

Thermonuclear Bursts with Short Recurrence Times from Neutron Stars Explained by Opacity-Driven Convection

NASA Technical Reports Server (NTRS)

Keek, L.; Heger, A.

2017-01-01

Thermonuclear flashes of hydrogen and helium accreted onto neutron stars produce the frequently observed Type I X-ray bursts. It is the current paradigm that almost all material burns in a burst, after which it takes hours to accumulate fresh fuel for the next burst. In rare cases, however, bursts are observed with recurrence times as short as minutes. We present the first one-dimensional multi-zone simulations that reproduce this phenomenon. Bursts that ignite in a relatively hot neutron star envelope leave a substantial fraction of the fuel unburned at shallow depths. In the wake of the burst, convective mixing events driven by opacity bring this fuel down to the ignition depth on the observed timescale of minutes. There, unburned hydrogen mixes with the metal-rich ashes, igniting to produce a subsequent burst. We find burst pairs and triplets, similar to the observed instances. Our simulations reproduce the observed fraction of bursts with short waiting times of approximately 30%, and demonstrate that short recurrence time bursts are typically less bright and of shorter duration.

Thermonuclear ignition in inertial confinement fusion and comparison with magnetic confinement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Betti, R.; Chang, P. Y.; Anderson, K. S.

2010-05-15

The physics of thermonuclear ignition in inertial confinement fusion (ICF) is presented in the familiar frame of a Lawson-type criterion. The product of the plasma pressure and confinement time Ptau for ICF is cast in terms of measurable parameters and its value is estimated for cryogenic implosions. An overall ignition parameter chi including pressure, confinement time, and temperature is derived to complement the product Ptau. A metric for performance assessment should include both chi and Ptau. The ignition parameter and the product Ptau are compared between inertial and magnetic-confinement fusion. It is found that cryogenic implosions on OMEGA[T. R. Boehlymore » et al., Opt. Commun. 133, 495 (1997)] have achieved Ptauapprox1.5 atm s comparable to large tokamaks such as the Joint European Torus [P. H. Rebut and B. E. Keen, Fusion Technol. 11, 13 (1987)] where Ptauapprox1 atm s. Since OMEGA implosions are relatively cold (Tapprox2 keV), their overall ignition parameter chiapprox0.02-0.03 is approx5x lower than in JET (chiapprox0.13), where the average temperature is about 10 keV.« less

Outbursts in Symbiotic Binaries

NASA Technical Reports Server (NTRS)

Sonneborn, George (Technical Monitor); Kenyon, Scott J.

2004-01-01

Two models have been proposed for the outbursts of symbiotic stars. In the thermonuclear model, outbursts begin when the hydrogen burning shell of a hot white dwarf reaches a critical mass. After a rapid increase in the luminosity and effective temperature, the white dwarf evolves at constant luminosity to lower effective temperatures, remains at optical maximum for several years, and then returns to quiescence along a white dwarf cooling curve. In disk instability models, the brightness rises when the accretion rate from the disk onto the central white dwarf abruptly increases by factors of 5-20. After a few month to several year period at maximum, both the luminosity and the effective temperature of the disk decline as the system returns to quiescence. If most symbiotic stars undergo thermonuclear eruptions, then symbiotics are probably poor candidates for type I supernovae. However, they can then provide approx. 10% of the material which stars recycle back into the interstellar medium. If disk instabilities are the dominant eruption mechanism, symbiotics are promising type Ia candidates but recycle less material into the interstellar medium.

Thermonuclear dynamo inside ultracentrifuge with supersonic plasma flow stabilization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Winterberg, F.

Einstein's general theory of relativity implies the existence of virtual negative masses in the rotational reference frame of an ultracentrifuge with the negative mass density of the same order of magnitude as the positive mass density of a neutron star. In an ultracentrifuge, the repulsive gravitational field of this negative mass can simulate the attractive positive mass of a mini-neutron star, and for this reason can radially confine a dense thermonuclear plasma placed inside the centrifuge, very much as the positive mass of a star confines its plasma by its own attractive gravitational field. If the centrifuge is placed inmore » an externally magnetic field to act as the seed field of a magnetohydrodynamic generator, the configuration resembles a magnetar driven by the release of energy through nuclear fusion, accelerating the plasma to supersonic velocities, with the magnetic field produced by the thermomagnetic Nernst effect insulating the hot plasma from the cold wall of the centrifuge. Because of the supersonic flow and the high plasma density the configuration is stable.« less

Demonstration of thermonuclear conditions in magnetized liner inertial fusion experiments

DOE PAGES

Gomez, Matthew R.; Slutz, Stephen A.; Sefkow, Adam B.; ...

2015-04-29

In this study, the magnetized liner inertial fusion concept [S. A. Slutz et al., Phys. Plasmas17, 056303 (2010)] utilizes a magnetic field and laser heating to relax the pressure requirements of inertial confinement fusion. The first experiments to test the concept [M. R. Gomez et al., Phys. Rev. Lett. 113, 155003 (2014)] were conducted utilizing the 19 MA, 100 ns Z machine, the 2.5 kJ, 1 TW Z Beamlet laser, and the 10 T Applied B-field on Z system. Despite an estimated implosion velocity of only 70 km/s in these experiments, electron and ion temperatures at stagnation were as highmore » as 3 keV, and thermonuclear deuterium-deuterium neutron yields up to 2 × 10 12 have been produced. X-ray emission from the fuel at stagnation had widths ranging from 50 to 110 μm over a roughly 80% of the axial extent of the target (6–8 mm) and lasted approximately 2 ns. X-ray yields from these experiments are consistent with a stagnation density of the hot fuel equal to 0.2–0.4 g/cm 3. In these experiments, up to 5 ×10 10 secondary deuterium-tritium neutrons were produced. Given that the areal density of the plasma was approximately 1–2 mg/cm 2, this indicates the stagnation plasma was significantly magnetized, which is consistent with the anisotropy observed in the deuterium-tritium neutron spectra. Control experiments where the laser and/or magnetic field were not utilized failed to produce stagnation temperatures greater than 1 keV and primary deuterium-deuterium yields greater than 10 10. An additional control experiment where the fuel contained a sufficient dopant fraction to substantially increase radiative losses also failed to produce a relevant stagnation temperature. The results of these experiments are consistent with a thermonuclear neutron source.« less

Demonstration of thermonuclear conditions in magnetized liner inertial fusion experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gomez, M. R.; Slutz, S. A.; Sefkow, A. B.

2015-05-15

The magnetized liner inertial fusion concept [S. A. Slutz et al., Phys. Plasmas 17, 056303 (2010)] utilizes a magnetic field and laser heating to relax the pressure requirements of inertial confinement fusion. The first experiments to test the concept [M. R. Gomez et al., Phys. Rev. Lett. 113, 155003 (2014)] were conducted utilizing the 19 MA, 100 ns Z machine, the 2.5 kJ, 1 TW Z Beamlet laser, and the 10 T Applied B-field on Z system. Despite an estimated implosion velocity of only 70 km/s in these experiments, electron and ion temperatures at stagnation were as high as 3 keV, and thermonuclear deuterium-deuterium neutronmore » yields up to 2 × 10{sup 12} have been produced. X-ray emission from the fuel at stagnation had widths ranging from 50 to 110 μm over a roughly 80% of the axial extent of the target (6–8 mm) and lasted approximately 2 ns. X-ray yields from these experiments are consistent with a stagnation density of the hot fuel equal to 0.2–0.4 g/cm{sup 3}. In these experiments, up to 5 × 10{sup 10} secondary deuterium-tritium neutrons were produced. Given that the areal density of the plasma was approximately 1–2 mg/cm{sup 2}, this indicates the stagnation plasma was significantly magnetized, which is consistent with the anisotropy observed in the deuterium-tritium neutron spectra. Control experiments where the laser and/or magnetic field were not utilized failed to produce stagnation temperatures greater than 1 keV and primary deuterium-deuterium yields greater than 10{sup 10}. An additional control experiment where the fuel contained a sufficient dopant fraction to substantially increase radiative losses also failed to produce a relevant stagnation temperature. The results of these experiments are consistent with a thermonuclear neutron source.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gorelenkov, Nikolai N

The area of energetic particle (EP) physics of fusion research has been actively and extensively researched in recent decades. The progress achieved in advancing and understanding EP physics has been substantial since the last comprehensive review on this topic by W.W. Heidbrink and G.J. Sadler [1]. That review coincided with the start of deuterium-tritium (DT) experiments on Tokamak Fusion Test reactor (TFTR) and full scale fusion alphas physics studies. Fusion research in recent years has been influenced by EP physics in many ways including the limitations imposed by the "sea" of Alfven eigenmodes (AE) in particular by the toroidicityinduced AEsmore » (TAE) modes and reversed shear Alfven (RSAE). In present paper we attempt a broad review of EP physics progress in tokamaks and spherical tori since the first DT experiments on TFTR and JET (Joint European Torus) including helical/stellarator devices. Introductory discussions on basic ingredients of EP physics, i.e. particle orbits in STs, fundamental diagnostic techniques of EPs and instabilities, wave particle resonances and others are given to help understanding the advanced topics of EP physics. At the end we cover important and interesting physics issues toward the burning plasma experiments such as ITER (International Thermonuclear Experimental Reactor).« less

Normal operation and maintenance safety lessons from the ITER US PbLi test blanket module program for a US FNSF and DEMO

DOE Office of Scientific and Technical Information (OSTI.GOV)

L. C. Cadwallader; C. P. C. Wong; M. Abdou

2014-10-01

A leading power reactor breeding blanket candidate for a fusion demonstration power plant (DEMO) being pursued by the US Fusion Community is the Dual Coolant Lead Lithium (DCLL) concept. The safety hazards associated with the DCLL concept as a reactor blanket have been examined in several US design studies. These studies identify the largest radiological hazards as those associated with the dust generation by plasma erosion of plasma blanket module first walls, oxidation of blanket structures at high temperature in air or steam, inventories of tritium bred in or permeating through the ferritic steel structures of the blanket module andmore » blanket support systems, and the 210Po and 203Hg produced in the PbLi breeder/coolant. What these studies lack is the scrutiny associated with a licensing review of the DCLL concept. An insight into this process was gained during the US participation in the International Thermonuclear Experimental Reactor (ITER) Test Blanket Module (TBM) Program. In this paper we discuss the lessons learned during this activity and make safety proposals for the design of a Fusion Nuclear Science Facility (FNSF) or a DEMO that employs a lead lithium breeding blanket.« less

Studying Turbulence Using Numerical Simulation Databases. No. 7; Proceedings of the Summer Program

NASA Technical Reports Server (NTRS)

1998-01-01

The Seventh Summer Program of the Center for Turbulence Research took place in the four-week period, July 5 to July 31, 1998. This was the largest CTR Summer Program to date, involving thirty-six participants from the U. S. and nine other countries. Thirty-one Stanford and NASA-Ames staff members facilitated and contributed to most of the Summer projects. A new feature, and perhaps a preview of the future programs, was that many of the projects were executed on non-NASA computers. These included supercomputers located in Europe as well as those operated by the Departments of Defense and Energy in the United States. In addition, several simulation programs developed by the visiting participants at their home institutions were used. Another new feature was the prevalence of lap-top personal computers which were used by several participants to carry out some of the work that in the past were performed on desk-top workstations. We expect these trends to continue as computing power is enhanced and as more researchers (many of whom CTR alumni) use numerical simulations to study turbulent flows. CTR's main role continues to be in providing a forum for the study of turbulence for engineering analysis and in facilitating intellectual exchange among the leading researchers in the field. Once again the combustion group was the largest. Turbulent combustion has enjoyed remarkable progress in using simulations to address increasingly complex and practically more relevant questions. The combustion group's studies included such challenging topics as fuel evaporation, soot chemistry, and thermonuclear reactions. The latter study was one of three projects related to the Department of Energy's ASCI Program (www.llnl.gov/asci); the other two (rocket propulsion and fire safety) were carried out in the turbulence modeling group. The flow control and acoustics group demonstrated a successful application of the so-called evolution algorithms which actually led to a previously unknown forcing strategy for jets yielding increased spreading rate. A very efficient algorithm for flow in complex geometries with moving boundaries based on the immersed boundary forcing technique was tested with very encouraging results. Also a new strategy for the destruction of aircraft trailing vortices was introduced and tested. The Reynolds Averaged Modeling (RANS) group demonstrated that the elliptic relaxation concept for RANS calculations is also applicable to transonic flows with shocks; however, prediction of laminar/turbulent transition remains an important pacing item. A large fraction of the LES effort was devoted to the development and testing of a new algorithmic procedure (as opposed to phenomenological model) for subgrid scale modeling based on regularized de-filtering of the flow variables. This appears to be a very promising approach, and a significant effort is currently underway to assess its robustness in high Reynolds number flows and in conjunction with numerical methods for complex flows. As part of the Summer Program two review tutorials were given on Turbulent structures in hydrocarbon pool fires (Sheldon Tieszen), and Turbulent combustion modeling: from RANS to LES via DNS (Luc Vervisch); and two seminars entitled Assessment of turbulence models for engineering applications (Paul Durbin) and Subgrid-scale modeling for non-premixed, turbulent reacting flows (James Riley) were presented. A number of colleagues from universities, government agencies, and industry attended the final presentations of the participants on July 31 and participated in the discussions. There are twenty-six papers in this volume grouped in five areas. Each group is preceded with an overview by its coordinator.

Neoclassical Theory and Its Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shaing, Ker-Chung

2015-11-20

The grant entitled Neoclassical Theory and Its Applications started on January 15 2001 and ended on April 14 2015. The main goal of the project is to develop neoclassical theory to understand tokamak physics, and employ it to model current experimental observations and future thermonuclear fusion reactors. The PI had published more than 50 papers in refereed journals during the funding period.

Water-quality assessment of part of the Upper Mississippi River Basin, Minnesota and Wisconsin - Ground-water quality in an agricultural area of Sherburne County, Minnesota, 1998

USGS Publications Warehouse

Ruhl, James F.; Fong, Alison L.; Hanson, Paul E.; Andrews, William J.

2000-01-01

Tritium concentrations had a range of from 7.5 to 18.8 tritium units (TUs) and a median of 12.5 TUs. These concentrations indicate that the ground water predominantly recharged after testing of thermonuclear weapons during the early 1950's.

The Origin of the United States Security Commitment to the Republic of Korea

DTIC Science & Technology

1987-06-01

and war and of the effect of these objectives on our strategic plans, in the light of the probable fission bomb capability and possible thermonuclear ... bomb capability of the Soviet Union. 226 A special ad hoc working group was formed under Nitze to conduct this study. This group took advantage of the

Beryllium processing technology review for applications in plasma-facing components

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castro, R.G.; Jacobson, L.A.; Stanek, P.W.

1993-07-01

Materials research and development activities for the International Thermonuclear Experimental Reactor (ITER), i.e., the next generation fusion reactor, are investigating beryllium as the first-wall containment material for the reactor. Important in the selection of beryllium is the ability to process, fabricate and repair beryllium first-wall components using existing technologies. Two issues that will need to be addressed during the engineering design activity will be the bonding of beryllium tiles in high-heat-flux areas of the reactor, and the in situ repair of damaged beryllium tiles. The following review summarizes the current technology associated with welding and joining of beryllium to itselfmore » and other materials, and the state-of-the-art in plasma-spray technology as an in situ repair technique for damaged beryllium tiles. In addition, a review of the current status of beryllium technology in the former Soviet Union is also included.« less

Physical Processes in the MAGO/MFT Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garanin, Sergey F; Reinovsky, Robert E.

2015-03-23

The Monograph is devoted to theoretical discussion of the physical effects, which are most significant for the alternative approach to the problem of controlled thermonuclear fusion (CTF): the MAGO/MTF approach. The book includes the description of the approach, its difference from the major CTF systems—magnetic confinement and inertial confinement systems. General physical methods of the processes simulation in this approach are considered, including plasma transport phenomena and radiation, and the theory of transverse collisionless shock waves, the surface discharges theory, important for such kind of research. Different flows and magneto-hydrodynamic plasma instabilities occurring in the frames of this approach aremore » also considered. In virtue of the general physical essence of the considered phenomena the presented results are applicable to a wide range of plasma physics and hydrodynamics processes. The book is intended for the plasma physics and hydrodynamics specialists, post-graduate students, and senior students-physicists.« less

Propagation of Plasma Bunches through a Transverse Magnetic Barrier

NASA Astrophysics Data System (ADS)

Bishaev, A. M.; Gavrikov, M. B.; Kozintseva, M. V.; Savel'ev, V. V.

2018-01-01

The injection of a plasma bunch into a multipolar trap can be applied to fill the trap with a plasma. The injection of the bunch into a tokamak-like trap can be considered an additional means for controlling the processes of plasma heating and fuel delivery to the central zone of a thermonuclear reactor. In both cases, the bunch is injected normally to the magnetic field of the trap. It has been shown theoretically, experimentally, and by numerical simulation that the depth of plasma bunch penetration into the magnetic field varies in direct proportion to the bunch energy and in inverse proportion to the magnetic pressure and the cross-sectional area of the plasma bunch. The data of this work allow researchers to estimate the values of plasma bunch parameters at which the bunch will be trapped. As a result, the process of plasma bunch trapping has been optimized.

Use of zooming and pulseshaping for acceleration to high velocities and fusion neutron production on the Nike laser

NASA Astrophysics Data System (ADS)

Karasik, Max; Weaver, J. L.; Aglitskiy, Y.; Kehne, D. M.; Zalesak, S. T.; Velikovich, A. L.; Oh, J.; Obenschain, S. P.; Arikawa, Y.

2011-10-01

We will present results from follow-on experiments to the record-high velocities of 1000 km/s achieved on Nike [Karasik et al, Phys. Plasmas 17, 056317(2010)], in which highly accelerated planar foils of deuterated polystyrene were made to collide with a witness foil to produce ~ 1 Gbar shock pressures and result in heating of matter to thermonuclear temperatures. Still higher velocities and higher target densities are required for impact fast ignition. The aim of these experiments is using the focal zoom capability of Nike and shaping the driving pulse to minimize shock heating of the accelerated target to achieve higher densities and velocities. In-flight target density is inferred from target heating upon collision via DD neutron time-of-flight ion temperature measurement. Work is supported by US DOE (NNSA) and Office of Naval Research. SAIC

High Energy Density Plasmas (HEDP) for studies of basic nuclear science relevant to Stellar and Big Bang Nucleosynthesis

NASA Astrophysics Data System (ADS)

Frenje, Johan

2014-06-01

Thermonuclear reaction rates and nuclear processes have been explored traditionally by means of conventional accelerator experiments, which are difficult to execute at conditions relevant to stellar nucleosynthesis. Thus, nuclear reactions at stellar energies are often studied through extrapolations from higher-energy data or in low-background underground experiments. Even when measurements are possible using accelerators at relevant energies, thermonuclear reaction rates in stars are inherently different from those in accelerator experiments. The fusing nuclei are surrounded by bound electrons in accelerator experiments, whereas electrons occupy mainly continuum states in a stellar environment. Nuclear astrophysics research will therefore benefit from an enlarged toolkit for studies of nuclear reactions. In this presentation, we report on the first use of High Energy Density Plasmas for studies of nuclear reactions relevant to basic nuclear science, stellar and Big Bang nucleosynthesis. These experiments were carried out at the OMEGA laser facility at University of Rochester and the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory, in which spherical capsules were irradiated with powerful lasers to compress and heat the fuel to high enough temperatures and densities for nuclear reactions to occur. Four experiments will be highlighted in this presentation. In the first experiment, the differential cross section for the elastic neutron-triton (n-T) scattering at 14.1 MeV was measured with significantly higher accuracy than achieved in accelerator experiments. In the second experiment, the T(t,2n)4He reaction, a mirror reaction to the 3He(3He,2p)4He reaction that plays an important role in the proton-proton chain that transforms hydrogen into ordinary 4He in stars like our Sun, was studied at energies in the range 15-40 keV. In the third experiment, the 3He+3He solar fusion reaction was studied directly, and in the fourth experiment, we probed the T+3He reaction, possibly relevant to Big Bang nucleosynthesis.

Design Features of the Neutral Particle Diagnostic System for the ITER Tokamak

NASA Astrophysics Data System (ADS)

Petrov, S. Ya.; Afanasyev, V. I.; Melnik, A. D.; Mironov, M. I.; Navolotsky, A. S.; Nesenevich, V. G.; Petrov, M. P.; Chernyshev, F. V.; Kedrov, I. V.; Kuzmin, E. G.; Lyublin, B. V.; Kozlovski, S. S.; Mokeev, A. N.

2017-12-01

The control of the deuterium-tritium (DT) fuel isotopic ratio has to ensure the best performance of the ITER thermonuclear fusion reactor. The diagnostic system described in this paper allows the measurement of this ratio analyzing the hydrogen isotope fluxes (performing neutral particle analysis (NPA)). The development and supply of the NPA diagnostics for ITER was delegated to the Russian Federation. The diagnostics is being developed at the Ioffe Institute. The system consists of two analyzers, viz., LENPA (Low Energy Neutral Particle Analyzer) with 10-200 keV energy range and HENPA (High Energy Neutral Particle Analyzer) with 0.1-4.0MeV energy range. Simultaneous operation of both analyzers in different energy ranges enables researchers to measure the DT fuel ratio both in the central burning plasma (thermonuclear burn zone) and at the edge as well. When developing the diagnostic complex, it was necessary to account for the impact of several factors: high levels of neutron and gamma radiation, the direct vacuum connection to the ITER vessel, implying high tritium containment, strict requirements on reliability of all units and mechanisms, and the limited space available for accommodation of the diagnostic hardware at the ITER tokamak. The paper describes the design of the diagnostic complex and the engineering solutions that make it possible to conduct measurements under tokamak reactor conditions. The proposed engineering solutions provide a safe—with respect to thermal and mechanical loads—common vacuum channel for hydrogen isotope atoms to pass to the analyzers; ensure efficient shielding of the analyzers from the ITER stray magnetic field (up to 1 kG); provide the remote control of the NPA diagnostic complex, in particular, connection/disconnection of the NPA vacuum beamline from the ITER vessel; meet the ITER radiation safety requirements; and ensure measurements of the fuel isotopic ratio under high levels of neutron and gamma radiation.

PREFACE: IX International Conference on Modern Techniques of Plasma Diagnostics and their Application

NASA Astrophysics Data System (ADS)

Savjolov, A. S.; Dodulad, E. I.

2016-01-01

The IX Conference on ''Modern Techniques of Plasma Diagnosis and their Application'' was held on 5 - 7 November, 2014 at National Research Nuclear University MEPhI (NRNU MEPhI). The goal of the conference was an exchange of information on both high-temperature and low-temperature plasma diagnostics as well as deliberation and analysis of various diagnostic techniques and their applicability in science, industry, ecology, medicine and other fields. The Conference also provided young scientists from scientific centres and universities engaged in plasma diagnostics with an opportunity to attend the lectures given by the leading specialists in this field as well as present their own results and findings. The first workshop titled ''Modern problems of plasma diagnostics and their application for control of chemicals and the environment'' took place at Moscow Engineering and Physics Institute (MEPhI) in June 1998 with the support of the Section on Diagnostics of the Council of Russian Academic of Science on Plasma Physics and since then these forums have been held at MEPhI every two years. In 2008 the workshop was assigned a conference status. More than 150 specialists on plasma diagnostics and students took part in the last conference. They represented leading Russian scientific centres (such as Troitsk Institute of Innovative and Thermonuclear Research, National Research Centre ''Kurchatov Institute'', Russian Federal Nuclear Centre - All-Russian Scientific Research Institute of Experimental Physics and others) and universities from Belarus, Ukraine, Germany, USA, Belgium and Sweden. About 30 reports were made by young researchers, students and post-graduate students. All presentations during the conference were broadcasted online over the internet with viewers in Moscow, Prague, St. Petersburgh and other cities. The Conference was held within the framework of the Centre of Plasma, Laser Research and Technology supported by MEPhI Academic Excellence Project (Russian Ministry of Education and Science contract 02.•03.21.0005 of August 27th 2013). Papers selected by the Program Committee for publishing were reviewed under control of invited editors Prof. Andrey Kukushkin, Dr. Sci. Alexander Kukushkin, Dr. Sci. Elena Baronova, Dr. Emil Dodulad. We would like to thank heartily all of the speakers, participants and organizing committee members for their contribution to the conference

Strategic Bombing and the Thermonuclear Breakthrough: An Example of Disconnected Defense Planning,

DTIC Science & Technology

1981-04-01

30 March 1944 attack against Nuremburg that saw the loss of 94 of about 800 aircraft (with serious damage to 72 others). However, while the British...tested a very powerful fission bomb, with the code name KING, that had an explosive yield of 500 kilotons. Its purpose was to provide the U.S. with an ex

ASTROPHYSICS: Astronomers Spot Their First Carbon Bomb.

PubMed

Irion, R

2000-11-17

Carbon on the surface of an ultradense star detonated in a 3-hour thermonuclear explosion, according to a report at a meeting here last week of the American Astronomical Society's High Energy Astrophysics Division. If confirmed, the burst would be the first known cosmic explosion fueled solely by carbon rather than hydrogen or helium and could verify or revise models of carbon combustion.

Detection of burning ashes from thermonuclear X-ray bursts

NASA Astrophysics Data System (ADS)

Kajava, J. J. E.; Nättilä, J.; Poutanen, J.; Cumming, A.; Suleimanov, V.; Kuulkers, E.

2017-01-01

When neutron stars (NS) accrete gas from low-mass binary companions, explosive nuclear burning reactions in the NS envelope fuse hydrogen and helium into heavier elements. The resulting thermonuclear (type-I) X-ray bursts produce energy spectra that are fit well with black bodies, but a significant number of burst observations show deviations from Planck spectra. Here we present our analysis of RXTE/PCA observations of X-ray bursts from the NS low-mass X-ray binary HETE J1900.1-2455. We have discovered that the non-Planckian spectra are caused by photoionization edges. The anticorrelation between the strength of the edges and the colour temperature suggests that the edges are produced by the nuclear burning ashes that have been transported upwards by convection and become exposed at the photosphere. The atmosphere model fits show that occasionally the photosphere can consist entirely of metals, and that the peculiar changes in blackbody temperature and radius can be attributed to the emergence and disappearance of metals in the photosphere. As the metals are detected already in the Eddington-limited phase, it is possible that a radiatively driven wind ejects some of the burning ashes into the interstellar space.

Theoretical Issues for Plasma Regimes to be Explored by the Ignitor Experiment

NASA Astrophysics Data System (ADS)

Cardinali, A.; Coppi, B.; Sonnino, G.

2014-10-01

At present, the Ignitor experiment is the only one designed and planned to approach and explore ignition regimes under controlled DT burning conditions. The machine parameters have been established on the basis of existing knowledge of the confinement properties of high density plasmas. A variety of improved confinement regimes are expected to be accessible by means of the available ICRH heating power in addition to the prevalent programmable Ohmic heating power and relying on the injection of high velocity pellets for density profile control. The relevance of the various known confinement regimes to the objectives of Ignitor is discussed. Among other theoretical efforts, a non-linear thermal energy balance equation is investigated to study the onset of thermonuclear instability in the plasmas expected to be produced in Ignitor. The equation for the temperature profile in the equilibrium state is solved with the resulting profiles in agreement with those obtained by a full transport code and commonly adopted scalings for them. The evolution of the thermonuclear instability that relies on the solution of the time dependent energy balance equation is obtained. Sponsored in part by the U.S. DOE.

EVIDENCE OF SPREADING LAYER EMISSION IN A THERMONUCLEAR SUPERBURST

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koljonen, K. I. I.; Kajava, J. J. E.; Kuulkers, E., E-mail: karri.koljonen@nyu.edu

2016-10-01

When a neutron star (NS) accretes matter from a companion star in a low-mass X-ray binary, the accreted gas settles onto the stellar surface through a boundary/spreading layer. On rare occasions the accumulated gas undergoes a powerful thermonuclear superburst powered by carbon burning deep below the NS atmosphere. In this paper, we apply the non-negative matrix factorization spectral decomposition technique to show that the spectral variations during a superburst from 4U 1636–536 can be explained by two distinct components: (1) the superburst emission characterized by a variable temperature blackbody radiation component and (2) a quasi-Planckian component with a constant, ∼2.5more » keV, temperature varying by a factor of ∼15 in flux. The spectrum of the quasi-Planckian component is identical in shape and characteristics to the frequency-resolved spectra observed in the accretion/persistent spectrum of NS low-mass X-ray binaries and agrees well with the predictions of the spreading layer model by Inogamov and Sunyaev. Our results provide yet more observational evidence that superbursts—and possibly also normal X-ray bursts—induce changes in the disc–star boundary.« less

Local Thermonuclear Runaways in Dwarf Novae?

NASA Astrophysics Data System (ADS)

Shara, Michael

2012-10-01

We have no hope of understanding the structure and evolution of a class of astrophysical objects if we cannot identify the dominant energy source of those objects.The Disk Instability Model {DIM} postulates that Dwarf Nova {DN} outbursts are powered by runaway accretion from an accretion disk onto a White Dwarf {WD} in a red dwarf-WD mass transferring binary. Ominously, HST observations {e.g. Sion et al. 2001} of WD surface abundances hint at a significant shortcoming of the DIM. The data from the present proposal will be able to unequivocally demonstrate if the observed highly Carbon-depleted and Nitrogen-enhanced abundances on WD surfaces {NOT predicted by DIM} vary with binary orbital phase, or throughout a DN quiescence cycle, or from cycle to cycle. These same data will test if predicted {but never observed} Local Thermonuclear Runaways {"Nuclear-powered mini-novas"} occur on the WDs of DN. Such events could trigger or even power DN, providing the long-sought physical mechanism of DN eruptions that DIM lacks. As a "free" bonus, the same data may also directly detect the diffusion of accreted metals in a WD atmosphere for the first time, or provide significant limits on the diffusion rate.

Tridimensional Thermonuclear Instability in Subignited Plasmas and on the Surface of the Pulsars

NASA Astrophysics Data System (ADS)

Cardinali, A.; Coppi, B.

2016-10-01

Tridimensional modes involving an increase of the electron temperature can be excited as a result of α-particle heating in subignited D-T fusion burning plasmas when a nearly time- independent external source of heating is applied. The analyzed modes are shown to emerge from an axisymmetric toroidal configurations and are radially localized around rational magnetic surfaces corresponding to q(r =r0) =m0 /n0 where m0 and n0 are the relevant poloidal and toroidal mode numbers. The radial width of the mode is of the order of the thermal scale distances δT =D⊥e th /D∥e th 1/4 (R0 /n0) 1/2(dlnq/dr)0-1/2. The mode has a rather severe damping rate, that has to be overcome by the relevant heating rate. Thus the temperature range to be considered is that where the D-T plasma reactivity undergoes a relatively large increase as a function of temperature. This kind of theory has been applied to the plasmas that are envisioned to be associated with surface of pulsar and be subjects to (spatially) inhomogenous thermonuclear burning. Sponsored in part by the US DOE.

A hydrodynamic study of a slow nova outburst. [computerized simulation of thermonuclear runaway in white dwarf envelope

NASA Technical Reports Server (NTRS)

Sparks, W. M.; Starrfield, S.; Truran, J. W.

1978-01-01

The paper reports use of a Lagrangian implicit hydrodynamics computer code incorporating a full nuclear-reaction network to follow a thermonuclear runaway in the hydrogen-rich envelope of a 1.25 solar-mass white dwarf. In this evolutionary sequence the envelope was assumed to be of normal (solar) composition and the resulting outburst closely resembles that of the slow nova HR Del. In contrast, previous CNO-enhanced models resemble fast nova outbursts. The slow-nova model ejects material by radiation pressure when the high luminosity of the rekindled hydrogen shell source exceeds the local Eddington luminosity of the outer layers. This is in contrast to the fast nova outburst where ejection is caused by the decay of the beta(+)-unstable nuclei. Nevertheless, radiation pressure probably plays a major role in ejecting material from the fast nova remnants. Therefore, the sequence from slow to fast novae can be interpreted as a sequence of white dwarfs with increasing amounts of enhanced CNO nuclei in their hydrogen envelopes, although other parameters such as the white-dwarf mass and accretion rate probably contribute to the observed variation between novae.

Evidence for Harmonic Content and Frequency Evolution of Oscillations During the Rising Phase of X-ray Bursts From 4U 1636-536

NASA Technical Reports Server (NTRS)

Bgattacharyya, Sudip; Strohmayer, E.

2005-01-01

We report on a study of the evolution of burst oscillation properties during the rising phase of X-ray bursts from 4U 1636-536 observed with the proportional counter array (PCA) on board the Rossi X-Ray Timing Explorer (RXTE) . We present evidence for significant harmonic structure of burst oscillation pulses during the early rising phases of bursts. This is the first such detection in burst rise oscillations, and is very important for constraining neutron star structure parameters and the equation of state models of matter at the core of a neutron star. The detection of harmonic content only during the initial portions of the burst rise is consistent with the theoretical expectation that with time the thermonuclear burning region becomes larger, and hence the fundamental and harmonic amplitudes both diminish. We also find, for the first time from this source, strong evidence of oscillation frequency increase during the burst rise. The timing behavior of harmonic content, amplitude, and frequency of burst rise oscillations may be important in understanding the spreading of thermonuclear flames under the extreme physical conditions on neutron star surfaces.

Symbiotic stars

NASA Technical Reports Server (NTRS)

Kafatos, M.; Michalitsianos, A. G.

1984-01-01

The physical characteristics of symbiotic star systems are discussed, based on a review of recent observational data. A model of a symbiotic star system is presented which illustrates how a cool red-giant star is embedded in a nebula whose atoms are ionized by the energetic radiation from its hot compact companion. UV outbursts from symbiotic systems are explained by two principal models: an accretion-disk-outburst model which describes how material expelled from the tenuous envelope of the red giant forms an inwardly-spiralling disk around the hot companion, and a thermonuclear-outburst model in which the companion is specifically a white dwarf which superheats the material expelled from the red giant to the point where thermonuclear reactions occur and radiation is emitted. It is suspected that the evolutionary course of binary systems is predetermined by the initial mass and angular momentum of the gas cloud within which binary stars are born. Since red giants and Mira variables are thought to be stars with a mass of one or two solar mass, it is believed that the original cloud from which a symbiotic system is formed can consist of no more than a few solar masses of gas.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jenke, P. A.; Linares, M.; Connaughton, V.

The Fermi Gamma-ray Burst Monitor (GBM) is an all-sky gamma-ray monitor well known in the gamma-ray burst (GRB) community. Although GBM excels in detecting the hard, bright extragalactic GRBs, its sensitivity above 8 keV and its all-sky view make it an excellent instrument for the detection of rare, short-lived Galactic transients. In 2010 March, we initiated a systematic search for transients using GBM data. We conclude this phase of the search by presenting a three-year catalog of 1084 X-ray bursts. Using spectral analysis, location, and spatial distributions we classified the 1084 events into 752 thermonuclear X-ray bursts, 267 transient eventsmore » from accretion flares and X-ray pulses, and 65 untriggered gamma-ray bursts. All thermonuclear bursts have peak blackbody temperatures broadly consistent with photospheric radius expansion (PRE) bursts. We find an average rate of 1.4 PRE bursts per day, integrated over all Galactic bursters within about 10 kpc. These include 33 and 10 bursts from the ultra-compact X-ray binaries 4U 0614+09 and 2S 0918-549, respectively. We discuss these recurrence times and estimate the total mass ejected by PRE bursts in our Galaxy.« less

The Fermi-GBM Three-year X-Ray Burst Catalog

NASA Astrophysics Data System (ADS)

Jenke, P. A.; Linares, M.; Connaughton, V.; Beklen, E.; Camero-Arranz, A.; Finger, M. H.; Wilson-Hodge, C. A.

2016-08-01

The Fermi Gamma-ray Burst Monitor (GBM) is an all-sky gamma-ray monitor well known in the gamma-ray burst (GRB) community. Although GBM excels in detecting the hard, bright extragalactic GRBs, its sensitivity above 8 keV and its all-sky view make it an excellent instrument for the detection of rare, short-lived Galactic transients. In 2010 March, we initiated a systematic search for transients using GBM data. We conclude this phase of the search by presenting a three-year catalog of 1084 X-ray bursts. Using spectral analysis, location, and spatial distributions we classified the 1084 events into 752 thermonuclear X-ray bursts, 267 transient events from accretion flares and X-ray pulses, and 65 untriggered gamma-ray bursts. All thermonuclear bursts have peak blackbody temperatures broadly consistent with photospheric radius expansion (PRE) bursts. We find an average rate of 1.4 PRE bursts per day, integrated over all Galactic bursters within about 10 kpc. These include 33 and 10 bursts from the ultra-compact X-ray binaries 4U 0614+09 and 2S 0918-549, respectively. We discuss these recurrence times and estimate the total mass ejected by PRE bursts in our Galaxy.

Comparison of the recently proposed super-Marx generator approach to thermonuclear ignition with the deuterium-tritium laser fusion-fission hybrid concept by the Lawrence Livermore National Laboratory

DOE PAGES

Winterberg, F.

2009-01-01

The recently proposed super-Marx generator pure deuterium microdetonation ignition concept is compared to the Lawrence Livermore National Ignition Facility (NIF) Laser deuterium-tritium fusion-fission hybrid concept (LIFE). In a super-Marx generator, a large number of ordinary Marx generators charge up a much larger second stage ultrahigh voltage Marx generator from which for the ignition of a pure deuterium microexplosion an intense GeV ion beam can be extracted. Typical examples of the LIFE concept are a fusion gain of 30 and a fission gain of 10, making up a total gain of 300, with about ten times more energy released into fissionmore » as compared to fusion. This means the substantial release of fission products, as in fissionless pure fission reactors. In the super-Marx approach for the ignition of pure deuterium microdetonation, a gain of the same magnitude can, in theory, be reached. If feasible, the super-Marx generator deuterium ignition approach would make lasers obsolete as a means for the ignition of thermonuclear microexplosions.« less

A Remarkable Three Hour Thermonuclear Burst from 4U 1820-30

NASA Technical Reports Server (NTRS)

Strohmayer, Tod E.; Brown, Edward F.; White, Nicholas E. (Technical Monitor)

2002-01-01

We present a detailed observational and theoretical study of an approximately three hour long X-ray burst (the "super burst") observed by the Rossi X-ray Timing Explorer (RXTE) from the low mass X-ray binary (LMXB) 4U 1820-30. This is the longest X-ray burst ever observed from this source, and perhaps one of the longest ever observed in great detail from any source. We show that the super burst is thermonuclear in origin. Its peak luminosity of approximately 3.4 x 10(exp 38) ergs s(exp -1) is consistent with the helium Eddington limit for a neutron star at approximately 7 kpc, as well as the peak luminosity of other, shorter, thermonuclear bursts from the same source. The super burst begins in the decaying tail of a more typical (approximately equal to 20 s duration) thermonuclear burst. These shorter, more frequent bursts are well known helium flashes from this source. The level of the accretion driven flux as well as the observed energy release of upwards of 1.5 x 10(exp 42) ergs indicate that helium could not be the energy source for the super burst. We outline the physics relevant to carbon production and burning on helium accreting neutron stars and present calculations of the thermal evolution and stability of a carbon layer and show that this process is the most likely explanation for the super burst. Ignition at the temperatures in the deep carbon "ocean" requires greater than 30 times the mass of carbon inferred from the observed burst energetics unless the He flash is able to trigger a deflagration from a much smaller mass of carbon. We show, however, that for large columns of accreted carbon fuel, a substantial fraction of the energy released in the carbon burning layer is radiated away as neutrinos, and the heat that is conducted from the burning layer in large part flows inward, only to be released on timescales longer than the observed burst. Thus the energy released during the event possibly exceeds that observed in X-rays by more than a factor of ten, making the scenario of burning a large mass of carbon at great depths consistent with the observed fluence without invoking any additional trigger. A strong constraint on this scenario is the recurrence time: to accrete an ignition column of 1013 g cm (exp -1) takes approximately 13/(M/3 x 10(exp 17) g s(exp -1) yr. Spectral analysis during the super burst reveals the presence of a broad emission line between 5.8 - 6.4 keV and an edge at 8 - 9 keV likely due to reflection of the burst flux from the inner accretion disk in 4U 1820-30. We believe this is the first time such a signature has been unambiguously detected in the spectrum of an X-ray burst.

Probing thermonuclear burning on accreting neutron stars

NASA Astrophysics Data System (ADS)

Keek, L.

2008-12-01

Neutron stars are the most compact stars that can be directly observed, which makes them ideal laboratories to study physics at extreme densities. Neutron stars in low-mass X-ray binaries accrete hydrogen and helium from a lower-mass companion star through Roche lobe overflow. This matter undergoes thermonuclear burning in the neutron star envelope, creating carbon and heavier elements. The fusion process may proceed in an unstable manner, resulting in a thermonuclear runaway. Within one second the entire surface is burned, which is observable as a sharp rise in the emitted X-ray flux: a type I X-ray burst. Afterwards the neutron star surface cools down on a timescale of ten to one hundred seconds. During these bursts the surface of an accreting neutron star can be observed directly, which makes them instrumental for studying this type of stars. We have studied rare kinds of X-ray bursts. One such rare burst is the superburst, which lasts a thousand times longer than an ordinary burst. Superbursts are thought to result from the explosive burning of a thick carbon layer, which lies deeper inside the neutron star, close to a layer known as the crust. A prerequisite for the occurrence of a superburst is a high enough temperature, which is set by the temperature of the crust and the heat conductivity of the envelope. The latter is lowered by the presence of heavy elements that are produced during normal X-ray bursts. Using a large set of observations from the Wide Field Camera's onboard the BeppoSAX satellite, we find that, at high accretion rate, sources which do not exhibit normal bursts likely have a longer superburst recurrence time, than the observed superburst recurrence time of one burster. We analyze in detail the first superburst from a transient source, which went into outburst only 55 days before the superburst. Recent models of the neutron star crust predict that this is too small a time to heat the crust sufficiently for superburst ignition, indicating that the models need to be extended with a new heat source. Another rare phenomenon is the occurrence of bursts with recurrence times of less than 30 minutes. In a long set of observations of the source EXO 0748-676 we find for the first time triple bursts, where three bursts occur within 30 minutes. This time is too short to accrete new fuel for the next burst, which suggests that not all hydrogen and helium is burned during the first burst. Finally, using a hydrodynamic stellar evolution code we create a multi-zone numerical model of the neutron star envelope. For the first time we include mixing due to rotation and a rotationally induced magnetic field. We find that thermonuclear burning proceeds in a stable manner at a lower heat flux of the crust for models including mixing. This may explain the observed transition of stable to unstable burning at a lower mass accretion rate than models previously predicted.

Cryogenic thermonuclear fuel implosions on the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glenzer, S. H.; Callahan, D. A.; MacKinnon, A. J.

2012-05-15

The first inertial confinement fusion implosion experiments with equimolar deuterium-tritium thermonuclear fuel have been performed on the National Ignition Facility. These experiments use 0.17 mg of fuel with the potential for ignition and significant fusion yield conditions. The thermonuclear fuel has been fielded as a cryogenic layer on the inside of a spherical plastic capsule that is mounted in the center of a cylindrical gold hohlraum. Heating the hohlraum with 192 laser beams for a total laser energy of 1.6 MJ produces a soft x-ray field with 300 eV temperature. The ablation pressure produced by the radiation field compresses themore » initially 2.2-mm diameter capsule by a factor of 30 to a spherical dense fuel shell that surrounds a central hot-spot plasma of 50 {mu}m diameter. While an extensive set of x-ray and neutron diagnostics has been applied to characterize hot spot formation from the x-ray emission and 14.1 MeV deuterium-tritium primary fusion neutrons, thermonuclear fuel assembly is studied by measuring the down-scattered neutrons with energies in the range of 10 to 12 MeV. X-ray and neutron imaging of the compressed core and fuel indicate a fuel thickness of (14 {+-} 3) {mu}m, which combined with magnetic recoil spectrometer measurements of the fuel areal density of (1 {+-} 0.09) g cm{sup -2} result in fuel densities approaching 600 g cm{sup -3}. The fuel surrounds a hot-spot plasma with average ion temperatures of (3.5 {+-} 0.1) keV that is measured with neutron time of flight spectra. The hot-spot plasma produces a total fusion neutron yield of 10{sup 15} that is measured with the magnetic recoil spectrometer and nuclear activation diagnostics that indicate a 14.1 MeV yield of (7.5{+-}0.1) Multiplication-Sign 10{sup 14} which is 70% to 75% of the total fusion yield due to the high areal density. Gamma ray measurements provide the duration of nuclear activity of (170 {+-} 30) ps. These indirect-drive implosions result in the highest areal densities and neutron yields achieved on laser facilities to date. This achievement is the result of the first hohlraum and capsule tuning experiments where the stagnation pressures have been systematically increased by more than a factor of 10 by fielding low-entropy implosions through the control of radiation symmetry, small hot electron production, and proper shock timing. The stagnation pressure is above 100 Gbars resulting in high Lawson-type confinement parameters of P{tau} Asymptotically-Equal-To 10 atm s. Comparisons with radiation-hydrodynamic simulations indicate that the pressure is within a factor of three required for reaching ignition and high yield. This will be the focus of future higher-velocity implosions that will employ additional optimizations of hohlraum, capsule and laser pulse shape conditions.« less

Semi-empirical studies of atomic structure. Progress report, 1 July 1982-1 February 1983

DOE Office of Scientific and Technical Information (OSTI.GOV)

Curtis, L.J.

1983-01-01

A program of studies of the properties of the heavy and highly ionized atomic systems which often occur as contaminants in controlled fusion devices is continuing. The project combines experimental measurements by fast-ion-beam excitation with semi-empirical data parametrizations to identify and exploit regularities in the properties of these very heavy and very highly ionized systems. The increasing use of spectroscopic line intensities as diagnostics for determining thermonuclear plasma temperatures and densities requires laboratory observation and analysis of such spectra, often to accuracies that exceed the capabilities of ab initio theoretical methods for these highly relativistic many electron systems. Through themore » acquisition and systematization of empirical data, remarkably precise methods for predicting excitation energies, transition wavelengths, transition probabilities, level lifetimes, ionization potentials, core polarizabilities, and core penetrabilities are being developed and applied. Although the data base for heavy, highly ionized atoms is still sparse, parametrized extrapolations and interpolations along isoelectronic, homologous, and Rydberg sequences are providing predictions for large classes of quantities, with a precision that is sharpened by subsequent measurements.« less

Semiempirical studies of atomic structure. Progress report, 1 July 1983-1 June 1984

DOE Office of Scientific and Technical Information (OSTI.GOV)

Curtis, L.J.

1984-01-01

A program of studies of the properties of the heavy and highly ionized atomic systems which often occur as contaminants in controlled fusion devices is continuing. The project combines experimental measurements by fast ion beam excitation with semiempirical data parametrizations to identify and exploit regularities in the properties of these very heavy and very highly ionized systems. The increasing use of spectroscopic line intensities as diagnostics for determining thermonuclear plasma temperatures and densities requires laboratory observation and analysis of such spectra, often to accuracies that exceed the capabilities of ab initio theoretical methods for these highly relativistic many electron systems.more » Through the acquisition and systematization of empirical data, remarkably precise methods for predicting excitation energies, transition wavelengths, transition probabilities, level lifetimes, ionization potentials, core polarizabilities, and core penetrabilities are being developed and applied. Although the data base for heavy, highly ionized atoms is still sparse, parametrized extrapolations and interpolations along isoelectronic, homologous, and Rydberg sequences are providing predictions for large classes of quantities, with a precision that is sharpened by subsequent measurements.« less

ToO Galactic Nova -- Michelle ``Quick Response''

NASA Astrophysics Data System (ADS)

Helton, L. Andrew; Woodward, Chick; Evans, Nye; Geballe, Tom; Spitzer Nova Team

2006-08-01

Stars are the engines of energy production and chemical evolution in our Universe, depositing radiative and mechanical energy into their environments and enriching the ambient ISM with elements synthesized in their interiors and dust grains condensed in their atmospheres. Classical novae (CN) contribute to this cycle of chemical enrichment through explosive nucleosynthesis and the violent ejection of material dredged from the white dwarf progenitor and mixed with the accreted surface layers. We propose to obtain mid-IR spectra of a new galactic CN in outburst to investigate aspects of the CN phenomenon including the in situ formation and mineralogy of nova dust and the elemental abundances resulting from thermonuclear runaway. Synoptic, high S/N Michelle spectra permit: 1) determination of the grain size distribution and mineral composition of nova dust; 2) estimation of chemical abundances of nova ejecta from coronal and other emission line spectroscopy; and 3) measurement of the density and masses of the ejecta. This Gemini `Target of Opportunity' initiative (trigger K=5- 8 mag, assuming adequate PWFS guide stars exist) complements our extensive Spitzer, Chandra, Swift, XMM-Newton CN DDT/ToO programs.

Synoptic Mid-IR Spectra ToO Novae

NASA Astrophysics Data System (ADS)

Helton, L. Andrew; Woodward, Chick; Evans, Nye; Geballe, Tom; Spitzer Nova Team

2007-02-01

Stars are the engines of energy production and chemical evolution in our Universe, depositing radiative and mechanical energy into their environments and enriching the ambient ISM with elements synthesized in their interiors and dust grains condensed in their atmospheres. Classical novae (CN) contribute to this cycle of chemical enrichment through explosive nucleosynthesis and the violent ejection of material dredged from the white dwarf progenitor and mixed with the accreted surface layers. We propose to obtain mid-IR spectra of a new galactic CN in outburst to investigate aspects of the CN phenomenon including the in situ formation and mineralogy of nova dust and the elemental abundances resulting from thermonuclear runaway. Synoptic, high S/N Michelle spectra permit: 1) determination of the grain size distribution and mineral composition of nova dust; 2) estimation of chemical abundances of nova ejecta from coronal and other emission line spectroscopy; and 3) measurement of the density and masses of the ejecta. This Gemini `Target of Opportunity' initiative (trigger K=5- 8 mag, assuming adequate PWFS guide stars exist) complements our extensive Spitzer, Chandra, Swift, XMM-Newton CN DDT/ToO programs.

Electron Impact Cross Sections for Molecular Lasers

DTIC Science & Technology

1984-04-27

range coumunication and surveillance, isotope separation, and controlled thermonuclear fussion . Among all kinds of lasers, the gaseous discharge...shape resonance of n symmetry (reviewed by Schulz, 1976). Like vibrational excitation from the ground state, such process from nuclear -excited states as...energy range specifically in the 1-4 eV resonant region. 4 - A. Vibrational Excitation of Nuclear -Excited N2 For vibrational excitation by

Protein crystal growth in low gravity

NASA Technical Reports Server (NTRS)

Feigelson, Robert S.

1992-01-01

A study is presented of the crystallization of isocitrate lyase (ICL) and the influence of the lack of thermal solutal convection in microgravity on the morphology of ICL crystals is discussed. The latest results of studies with thermonucleation are presented. These include the nucleation of a protein with retrograde solubility and an unknown solubility curve. A new design for a more microgravity compatible thermonuclear is presented.

REACTOR

DOEpatents

Spitzer, L. Jr.

1962-01-01

The system conteraplates ohmically heating a gas to high temperatures such as are useful in thermonuclear reactors of the stellarator class. To this end the gas is ionized and an electric current is applied to the ionized gas ohmically to heat the gas while the ionized gas is confined to a central portion of a reaction chamber. Additionally, means are provided for pumping impurities from the gas and for further heating the gas. (AEC)

On Coulomb collisions in the solar wind

NASA Astrophysics Data System (ADS)

Hellinger, P.; Travnicek, P. M.

2009-04-01

Collisional transport in anisotropic plasmas is investigated comparing theoretical predictions of the Fokker-Planck equation for bi-Maxwellian particle distribution functions (Kogan, 1961; Lehner, 1967) and results of the corresponding Langevin equation. References: Kogan, V. I., in Plasma Physics and the Problem of Controlled Thermonuclear Reactions, edited by M. A. Leontovich, Pergamon Press, New York, , vol. 1, 153, 1961. Lehner, G., Zeitschrift fur Physik, 206, 284, 1967.

Astrophysical factors: Zero energy vs most effective energy

NASA Astrophysics Data System (ADS)

Liolios, Theodore E.

2001-07-01

Effective astrophysical factors for nonresonant astrophysical nuclear reaction are usually calculated with respect to a zero-energy limit. In the present work that limit is shown to be very disadvantageous compared to the more natural effective-energy limit. The latter is used in order to modify the thermonuclear reaction rate formula in stellar evolution codes so that it takes into account both plasma and laboratory screening effects.

Pulsating Instability of Turbulent Thermonuclear Flames in Type Ia Supernovae

NASA Astrophysics Data System (ADS)

Poludnenko, Alexei Y.

2014-01-01

Presently, one of the main explosion scenarios of type Ia supernovae (SNIa), aimed at explaining both "normal" and subluminous events, is the thermonuclear incineration of a white-dwarf in a single-degenerate system. The underlying engine of such explosions is the turbulent thermonuclear flame. Modern, large-scale, multidimensional simulations of SNIa cannot resolve the internal flame structure, and instead must include a subgrid-scale prescription for the turbulent-flame properties. As a result, development of robust, parameter-free, large-scale models of SNIa crucially relies on the detailed understanding of the turbulent flame properties during each stage of the flame evolution. Due to the complexity of the flame dynamics, such understanding must be validated by the first-principles direct numerical simulations (DNS). In our previous work, we showed that sufficiently fast turbulent flames are inherently susceptible to the development of detonations, which may provide the mechanism for the deflagration-to-detonation transition (DDT) in the delayed-detonation model of SNIa. Here we extend this study by performing detailed analysis of the turbulent flame properties at turbulent intensities below the critical threshold for DDT. We carried out a suite of 3D DNS of turbulent flames for a broad range of turbulent intensities and system sizes using a simplified, single-step, Arrhenius-type reaction kinetics. Our results show that at the later stages of the explosion, as the turbulence intensity increases prior to the possible onset of DDT, the flame front will become violently unstable. We find that the burning rate exhibits periodic pulsations with the energy release rate varying by almost an order of magnitude. Furthermore, such flame pulsations can produce pressure waves and shocks as the flame speed approaches the critical Chapman-Jouguet deflagration speed. Finally, in contrast with the current theoretical understanding, such fast turbulent flames can propagate at speeds, which are much higher than the characteristic speeds of turbulent fluctuations. These effects can qualitatively change the dynamics of the explosion and, therefore, must be properly accounted for in the turbulent-flame subgrid-scale models.

Mission and Objectives for the X-1 Advanced Radiation Source*

NASA Astrophysics Data System (ADS)

Rochau, Gary E.; Ramirez, Juan J.; Raglin, Paul S.

1998-11-01

Sandia National Laboratories PO Box 5800, MS-1178, Albuquerque, NM 87185 The X-1 Advanced Radiation Source represents a next step in providing the U.S. Department of Energy's Stockpile Stewardship Program with the high-energy, large volume, laboratory x-ray source for the Radiation Effects Science and Simulation, Inertial Confinement Fusion, and Weapon Physics Programs. Advances in fast pulsed power technology and in z-pinch hohlraums on Sandia National Laboratories' Z Accelerator provide sufficient basis for pursuing the development of X-1. The X-1 plan follows a strategy based on scaling the 2 MJ x-ray output on Z via a 3-fold increase in z-pinch load current. The large volume (>5 cm3), high temperature (>150 eV), temporally long (>10 ns) hohlraums are unique outside of underground nuclear weapon testing. Analytical scaling arguments and hydrodynamic simulations indicate that these hohlraums at temperatures of 230-300 eV will ignite thermonuclear fuel and drive the reaction to a yield of 200 to 1,200 MJ in the laboratory. Non-ignition sources will provide cold x-ray environments (<15 keV) and high yield fusion burn sources will provide high fidelity warm x-ray environments (15 keV-80 keV). This paper will introduce the X-1 Advanced Radiation Source Facility Project, describe the project mission, objective, and preliminary schedule.

Evolutionary Grids of Accreting White Dwarf Companions in Cataclysmic Variables

NASA Astrophysics Data System (ADS)

Benjamin, J.; Jensen, M.; Nadeau, S.; Nelson, L. A.

2003-12-01

We analyze the evolution of accreting white dwarfs in binary systems for a wide range of initial conditions. Specifically, evolutionary tracks are calculated for CO white dwarfs with masses in the range of 0.6 - 1.3 solar masses and accreting H-rich gas at rates of between 10-6 to 10-10 solar masses per year. Since the white dwarfs in these binaries could be very young or very old at the onset of mass transfer we simulated this possibility by investigating the evolution for a large range of internal temperatures. Thus most of the sequences generated were not thermally relaxed at the onset of mass transfer (and the thermonuclear flashes were not cyclic). We discuss the temporal dependence of the interior properties (envelope readjustment on a thermal timescale and compressional heating) on the initial conditions. Particular attention is paid to the white dwarfs accretors that remained small (relative to the Roche lobe radius) during the shell flash event. Finally, we use the results of these models to comment on the observed properties of Supersoft X-ray sources. This research was supported in part by funds from the Natural Sciences and Engineering Research Council (Canada).

Static magnetic fields: A summary of biological interactions, potential health effects, and exposure guidelines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tenforde, T.S.

1992-05-01

Interest in the mechanisms of interaction and the biological effects of static magnetic fields has increased significantly during the past two decades as a result of the growing number of applications of these fields in research, industry and medicine. A major stimulus for research on the bioeffects of static magnetic fields has been the effort to develop new technologies for energy production and storage that utilize intense magnetic fields (e.g., thermonuclear fusion reactors and superconducting magnet energy storage devices). Interest in the possible biological interactions and health effects of static magnetic fields has also been increased as a result ofmore » recent developments in magnetic levitation as a mode of public transportation. In addition, the rapid emergence of magnetic resonance imaging as a new clinical diagnostic procedure has, in recent years, provided a strong rationale for defining the possible biological effects of magnetic fields with high flux densities. In this review, the principal interaction mechanisms of static magnetic fields will be described, and a summary will be given of the present state of knowledge of the biological, environmental, and human health effects of these fields.« less

Hydrodynamic Simulations of Classical Novae: Accretion onto CO White Dwarfs as SN Ia Progenitors

NASA Astrophysics Data System (ADS)

Starrfield, Sumner; Bose, Maitrayee; Iliadis, Christian; Hix, William R.; José, Jordi; Hernanz, Margarita

2017-06-01

We have continued our studies of accretion onto white dwarfs by following the evolution of thermonuclear runaways on Carbon Oxygen (CO) white dwarfs. We have varied the mass of the white dwarf and the composition of the accreted material but chosen to keep the mass accretion rate at 2 x 10^{-10} solar masses per year to obtain the largest amount of accreted material possible with rates near to those observed. We assume either 25% core material or 50% core material has been mixed into the accreting material prior to the explosion. We use our 1D, lagrangian, hydrodynamic code: NOVA. We will report on the results of these simulations and compare the ejecta abundances to those measured in pre-solar grains that are thought to arise from classical nova explosions. These results will also be compared to recent results with SHIVA (Jose and Hernanz). We find that in all cases and for all white dwarf masses that less mass is ejected than accreted and, therefore, the white dwarf is growing in mass as a result of the accretion and resulting explosion.This work was supported in part by NASA under the Astrophysics Theory Program grant 14-ATP14-0007 and the U.S. DOE under Contract No. DE-FG02- 97ER41041. SS acknowledges partial support from NASA, NSF, and HST grants to ASU and WRH is supported by the U.S. Department of Energy, Office of Nuclear Physics. The results reported herein benefitted from collaborations and/or information exchange within NASA’s Nexus for Exoplanet System Science (NExSS) research coordination network sponsored by NASA’s Science Mission Directorate.

Environmental Assessment: Demolition of Munitions Storage Area Facilities at Ellsworth AFB, South Dakota

DTIC Science & Technology

2009-11-01

Eglin Parkway,Shalimar,FL,32579 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR...separately secured installation between 1950 and 1962 responsible for the storage, maintenance, and loading of atomic and thermonuclear weapons. The...portion of Ellsworth AFB and was operational between 1950 and 1962 (ACC 1997). It was operated by Air Force Materiel Command (AFMC), Armed Forces

Method of producing encapsulated thermonuclear fuel particles

DOEpatents

Smith, Warren H.; Taylor, William L.; Turner, Harold L.

1976-01-01

A method of producing a fuel particle is disclosed, which comprises forming hollow spheroids which have a mass number greater than 50, immersing said spheroids while under the presence of pressure and heat in a gaseous atmosphere containing an isotope, such as deuterium and tritium, so as to diffuse the gas into the spheroid and thereafter cooling said spheroids up to about 77.degree. Kelvin to about 4.degree. Kelvin.

Helium-3 blankets for tritium breeding in fusion reactors

NASA Technical Reports Server (NTRS)

Steiner, Don; Embrechts, Mark; Varsamis, Georgios; Vesey, Roger; Gierszewski, Paul

1988-01-01

It is concluded that He-3 blankets offers considerable promise for tritium breeding in fusion reactors: good breeding potential, low operational risk, and attractive safety features. The availability of He-3 resources is the key issue for this concept. There is sufficient He-3 from decay of military stockpiles to meet the International Thermonuclear Experimental Reactor needs. Extraterrestrial sources of He-3 would be required for a fusion power economy.

Comparisons Of Two- And Three-Dimensional Convection In Type I X-Ray Bursts

DOE PAGES

Zingale, M.; Malone, C. M.; Nonaka, A.; ...

2015-07-01

We perform the first detailed three-dimensional simulation of low Mach number convection preceding runaway thermonuclear ignition in a mixed H/He X-ray burst. Our simulations include a moderate-sized, approximate network that captures hydrogen and helium burning up through rp-process breakout. We look at the difference between two- and three-dimensional convective fields, including the details of the turbulent convection.

Repetitive output laser system and method using target reflectivity

DOEpatents

Johnson, Roy R.

1978-01-01

An improved laser system and method for implosion of a thermonuclear fuel pellet in which that portion of a laser pulse reflected by the target pellet is utilized in the laser system to initiate a succeeding target implosion, and in which the energy stored in the laser system to amplify the initial laser pulse, but not completely absorbed thereby, is used to amplify succeeding laser pulses initiated by target reflection.

APPARATUS FOR HEATING A PLASMA

DOEpatents

Stix, T.H.

1962-01-01

The system contemplates the use of ion cyclotron motions for transferring energy to a plasma immersed in a confining magnetic field such as is found in thermonuclear reactors of the stellarator class. Oppositely directed windings are provided for producing ion-accelerating fields having a time and spatial periodicity and these have the advantage of producing ion cyclotron motions without the development of space charges which preclude the efficient energy transfer to the plasma. (AEC)

APPARATUS FOR THE DENSIFICATION AND ENERGIZATION OF CHARGED PARTICLES

DOEpatents

Post, R.F.; Coensgen, F.H.

1962-12-18

This patent relates to a device for materially increasing the energy and density of a plasma to produce conditions commensurate with the establishment and promotion of controlled thermonuclear reactions. To this end the device employs three successive stages of magnetic compression, each stage having magnetic mirrors to compress a plasma, the mirrors being moveable to transfer the plasma to successive stages for further compression. Accordingly, a plasma introduced to the first stage is increased in density and energy in stepwide fashion by virtue of the magnetic compression in the successive stages such that the plasma upon reaching the last stage is of extremely high energy and density commensurate the plasma particles undergoing thermonuclear reactions. The principal novelty of the device resides in the provision of a unidirectional magnetic field which increases in stepwise fashion in coaxially communicating compression chambers of progressively decreasing lengths and diameters. Pulsed magnetic fields are superimposed upon the undirectional field and are manipulated to establish resultant magnetic compression fields which increase in intensity and progressively move, with respect to time, through the compression chambers in the direction of the smallest one thereof. The resultant field in the last compression chamber is hence of relatively high intensity, and the density and energy of the plasma confined therein are correspondingly high. (AEC)

Comparison of the Recently proposed Super Marx Generator Approach to Thermonuclear Ignition with the DT Laser Fusion-Fission Hybrid Concept (LIFE) by the Lawrence Livermore National Laboratory.

NASA Astrophysics Data System (ADS)

Winterberg, Friedwardt

2009-05-01

The recently proposed Super Marx pure deuterium micro-detonation ignition concept [1] is compared to the Lawrence Livermore National Ignition Facility (NIF) laser DT fusion-fission hybrid concept (LIFE) [2]. A typical example of the LIFE concept is a fusion gain 30, and a fission gain of 10, making up for a total gain of 300, with about 10 times more energy released into fission as compared to fusion. This means a substantial release of fission products, as in fusion-less pure fission reactors. In the Super Marx approach for the ignition of a pure deuterium micro-detonation gains of the same magnitude can in theory be reached. If the theoretical prediction can be supported by more elaborate calculations, the Super Marx approach is likely to make lasers obsolete as a means for the ignition of thermonuclear micro-explosions. [1] ``Ignition of a Deuterium Micro-Detonation with a Gigavolt Super Marx Generator,'' Winterberg, F., Journal of Fusion Energy, Springer, 2008. http://www.springerlink.com/content/r2j046177j331241/fulltext.pdf. [2] ``LIFE: Clean Energy from Nuclear Waste,'' https://lasers.llnl.gov/missions/energy&_slash;for&_slash;the&_slash;future/life/

Effect of particle pinch on the fusion performance and profile features of an international thermonuclear experimental reactor-like fusion reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Shijia, E-mail: wangsg@mail.ustc.edu.cn; Wang, Shaojie

2015-04-15

The evolution of the plasma temperature and density in an international thermonuclear experimental reactor (ITER)-like fusion device has been studied by numerically solving the energy transport equation coupled with the particle transport equation. The effect of particle pinch, which depends on the magnetic curvature and the safety factor, has been taken into account. The plasma is primarily heated by the alpha particles which are produced by the deuterium-tritium fusion reactions. A semi-empirical method, which adopts the ITERH-98P(y,2) scaling law, has been used to evaluate the transport coefficients. The fusion performances (the fusion energy gain factor, Q) similar to the ITERmore » inductive scenario and non-inductive scenario (with reversed magnetic shear) are obtained. It is shown that the particle pinch has significant effects on the fusion performance and profiles of a fusion reactor. When the volume-averaged density is fixed, particle pinch can lower the pedestal density by ∼30%, with the Q value and the central pressure almost unchanged. When the particle source or the pedestal density is fixed, the particle pinch can significantly enhance the Q value by  60%, with the central pressure also significantly raised.« less

Beryllium fabrication/cost assessment for ITER (International Thermonuclear Experimental Reactor)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beeston, J.M.; Longhurst, G.R.; Parsonage, T.

1990-06-01

A fabrication and cost estimate of three possible beryllium shapes for the International Thermonuclear Experimental Reactor (ITER) blanket is presented. The fabrication method by hot pressing (HP), cold isostatic pressing plus sintering (CIP+S), cold isostatic pressing plus sintering plus hot isostatic pressing (CIP+S+HIP), and sphere production by atomization or rotary electrode will be discussed. Conventional hot pressing blocks of beryllium with subsequent machining to finished shapes can be more expensive than production of a net shape by cold isostatic pressing and sintering. The three beryllium shapes to be considered here and proposed for ITER are: (1) cubic blocks (3 tomore » 17 cm on an edge), (2) tubular cylinders (33 to 50 mm i.d. by 62 mm o.d. by 8 m long), and (3) spheres (1--5 mm dia.). A rough cost estimate of the basic shape is presented which would need to be refined if the surface finish and tolerances required are better than the sintering process produces. The final cost of the beryllium in the blanket will depend largely on the machining and recycling of beryllium required to produce the finished product. The powder preparation will be discussed before shape fabrication. 10 refs., 6 figs.« less

Binary Orbits as the Driver of Gamma-Ray Emission and Mass Ejection in Classical Novae

NASA Technical Reports Server (NTRS)

Chomiuk, Laura; Linford, Justin D.; Yang, Jun; O'Brien, T. J.; Paragi, Zsolt; Mioduszewski, Amy J.; Beswick, R. J.; Cheung, C. C.; Mukai, Koji; Nelson, Thomas

2014-01-01

Classical novae are the most common astrophysical thermonuclear explosions, occurring on the surfaces of white dwarf stars accreting gas from companions in binary star systems. Novae typically expel about 10 (sup -4) solar masses of material at velocities exceeding 1,000 kilometers per second.However, the mechanism of mass ejection in novae is poorly understood, and could be dominated by the impulsive flash of thermonuclear energy, prolonged optically thick winds or binary interaction with the nova envelope. Classical novae are now routinely detected at giga-electronvolt gamma-ray wavelengths, suggesting that relativistic particles are accelerated by strong shocks in the ejecta. Here we report high-resolution radio imaging of the gamma-ray-emitting nova V959 Mon. We find that its ejecta were shaped by the motion of the binary system: some gas was expelled rapidly along the poles as a wind from the white dwarf, while denser material drifted out along the equatorial plane, propelled by orbital motion..At the interface between the equatorial and polar regions, we observe synchrotron emission indicative of shocks and relativistic particle acceleration, thereby pinpointing the location of gamma-ray production. Binary shaping of the nova ejecta and associated internal shocks are expected to be widespread among novae, explaining why many novae are gamma-ray emitters.

Pulse Power Compression by Cutting a Dense Z-Pinch with a Laser Beam

NASA Astrophysics Data System (ADS)

Winterberg, F.

1999-07-01

A thin cut made through a z-pinch by an intense laser beam can become a magnetically insulated diode crossed by an intense ion beam. For larger cuts, the gap is crossed by an intense relativistic electron beam, stopped by magnetic bremsstrahlung resulting in a pointlike intense x-ray source. In either case, the impedance of the pinch discharge is increased, with the power delivered rising in the same pro-portion. A magnetically insulated cut is advantageous for three reasons: First, with the ion current com-parable to the Alfvèn ion current, the pinch instabilities are reduced. Second, with the energy deposit-ed into fast ions, a non-Maxwellian velocity distribution is established increasing<σ ν> value for nuclear fusion reactions taking place in the pinch discharge. Third, in a high density z-pinch plasma, the intense ion beam can launch a thermonuclear detonation wave propagating along the pinch discharge channel. For larger cuts the soft x-rays produced by magnetic bremsstrahlung can be used to drive a thermonuclear hohlraum target. Finally, the proposed pulse power compression scheme permits to use a cheap low power d.c. source charging a magnetic storage coil delivering the magnetically stored energy to the pinch discharge load by an exploding wire opening switch.

Developing the Polynomial Expressions for Fields in the ITER Tokamak

NASA Astrophysics Data System (ADS)

Sharma, Stephen

2017-10-01

The two most important problems to be solved in the development of working nuclear fusion power plants are: sustained partial ignition and turbulence. These two phenomena are the subject of research and investigation through the development of analytic functions and computational models. Ansatz development through Gaussian wave-function approximations, dielectric quark models, field solutions using new elliptic functions, and better descriptions of the polynomials of the superconducting current loops are the critical theoretical developments that need to be improved. Euler-Lagrange equations of motion in addition to geodesic formulations generate the particle model which should correspond to the Dirac dispersive scattering coefficient calculations and the fluid plasma model. Feynman-Hellman formalism and Heaviside step functional forms are introduced to the fusion equations to produce simple expressions for the kinetic energy and loop currents. Conclusively, a polynomial description of the current loops, the Biot-Savart field, and the Lagrangian must be uncovered before there can be an adequate computational and iterative model of the thermonuclear plasma.

Expressions for Fields in the ITER Tokamak

NASA Astrophysics Data System (ADS)

Sharma, Stephen

2017-10-01

The two most important problems to be solved in the development of working nuclear fusion power plants are: sustained partial ignition and turbulence. These two phenomenon are the subject of research and investigation through the development of analytic functions and computational models. Ansatz development through Gaussian wave-function approximations, dielectric quark models, field solutions using new elliptic functions, and better descriptions of the polynomials of the superconducting current loops are the critical theoretical developments that need to be improved. Euler-Lagrange equations of motion in addition to geodesic formulations generate the particle model which should correspond to the Dirac dispersive scattering coefficient calculations and the fluid plasma model. Feynman-Hellman formalism and Heaviside step functional forms are introduced to the fusion equations to produce simple expressions for the kinetic energy and loop currents. Conclusively, a polynomial description of the current loops, the Biot-Savart field, and the Lagrangian must be uncovered before there can be an adequate computational and iterative model of the thermonuclear plasma.

Dense Plasma Focus: physics and applications (radiation material science, single-shot disclosure of hidden illegal objects, radiation biology and medicine, etc.)

NASA Astrophysics Data System (ADS)

Gribkov, V. A.; Miklaszewski, R.; Paduch, M.; Zielinska, E.; Chernyshova, M.; Pisarczyk, T.; Pimenov, V. N.; Demina, E. V.; Niemela, J.; Crespo, M.-L.; Cicuttin, A.; Tomaszewski, K.; Sadowski, M. J.; Skladnik-Sadowska, E.; Pytel, K.; Zawadka, A.; Giannini, G.; Longo, F.; Talab, A.; Ul'yanenko, S. E.

2015-03-01

The paper presents some outcomes obtained during the year of 2013 of the activity in the frame of the International Atomic Energy Agency Co-ordinated research project "Investigations of Materials under High Repetition and Intense Fusion-Relevant Pulses". The main results are related to the effects created at the interaction of powerful pulses of different types of radiation (soft and hard X-rays, hot plasma and fast ion streams, neutrons, etc. generated in Dense Plasma Focus (DPF) facilities) with various materials including those that are counted as perspective ones for their use in future thermonuclear reactors. Besides we discuss phenomena observed at the irradiation of biological test objects. We examine possible applications of nanosecond powerful pulses of neutrons to the aims of nuclear medicine and for disclosure of hidden illegal objects. Special attention is devoted to discussions of a possibility to create extremely large and enormously diminutive DPF devices and probabilities of their use in energetics, medicine and modern electronics.

Staged Z-pinch Experiments on Cobra and Zebra

NASA Astrophysics Data System (ADS)

Wessel, Frank J.; Anderson, A.; Banasek, J. T.; Byvank, T.; Conti, F.; Darling, T. W.; Dutra, E.; Glebov, V.; Greenly, J.; Hammer, D. A.; Potter, W. M.; Rocco, S. V.; Ross, M. P.; Ruskov, E.; Valenzuela, J.; Beg, F.; Covington, A.; Narkis, J.; Rahman, H. U.

2017-10-01

A Staged Z-pinch (SZP), configured as a pre-magnetized, high-Z (Ar, or Kr) annular liner imploding onto a low-Z (H, or D) target, was tested on the Cornell University, Cobra Facility and the University of Nevada, Reno, Zebra Facility; each characterized similarly by a nominal 1-MA current and 100-ns risetime while possessing different diagnostic packages. XUV-fast imaging reveals that the SZP implosion dynamics is similar on both machines and that it is more stable with an axial (Bz) magnetic field, a target, or both, than without. On Zebra, where neutron production is possible, reproducible thermonuclear (DD) yields were recorded at levels in excess of 109/shot. Flux compression in the SZP is also expected to produce magnetic field intensities of the order of kilo-Tesla. Thus, the DD reaction produced tritions should also yield secondary DT neutrons. Indeed, secondaries are measured above the noise threshold at levels approaching 106/shot. Funded by the Advanced Research Projects Agency - Energy, under Grant Number DE-AR0000569.

High heat flux burnout in subcooled flow boiling

NASA Astrophysics Data System (ADS)

Celata, G. P.; Cumo, M.; Mariani, A.

1995-09-01

The paper reports the results of an experimental research carried out at the Heat Transfer Division of the Energy Department, C.R. Casaccia, on the thermal hydraulic characterization of subcooled flow boiling CHF under typical conditions of thermonuclear fusion reactors, i.e. high liquid velocity and subcooling. The experiment was carried out exploring the following parameters: channel diameter (from 2.5 to 8.0 mm), heated length (10 and 15 cm), liquid velocity (from 2 to 40 m/s), exit pressure (from atmospheric to 5.0 MPa), inlet temperature (from 30 to 80 °C), channel orientation (vertical and horizontal). A maximum CHF value of 60.6 MW/m2 has been obtained under the following conditions: T in=30°, p=2.5 MPa, u=40 m/s, D=2.5 mm (smooth channel) Turbulence promoters (helically coiled wires) have been employed to further enhance the CHF attainable with subcooled flow boiling. Helically coiled wires allow an increase of 50% of the maximum CHF obtained with smooth channels.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klem, Michael

The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory seeks to achieve thermonuclear ignition through inertial confinement fusion. The accurate assessment of the performance of each implosion experiment is a crucial step. Here we report on work to derive a reliable electron temperature for the cryogenic deuteriumtritium implosions completed on the NIF using the xray signal from the Ross filter diagnostic. These Xrays are dominated by bremsstrahlung emission. By fitting the xray signal measured through each of the individual Ross filters, the source bremsstrahlung spectrum can be inferred, and an electron temperature of the implosion hot spot inferred.more » Currently, each filter is weighted equally in this analysis. We present work quantifying the errors with such a technique and the results from investigating the contribution of each filter to the overall accuracy of the temperature inference. Using this research, we also compare the inferred electron temperature against other measured implosion quantities to develop a more complete understanding of the hotspot physics.« less

The PRIMA Test Facility: SPIDER and MITICA test-beds for ITER neutral beam injectors

NASA Astrophysics Data System (ADS)

Toigo, V.; Piovan, R.; Dal Bello, S.; Gaio, E.; Luchetta, A.; Pasqualotto, R.; Zaccaria, P.; Bigi, M.; Chitarin, G.; Marcuzzi, D.; Pomaro, N.; Serianni, G.; Agostinetti, P.; Agostini, M.; Antoni, V.; Aprile, D.; Baltador, C.; Barbisan, M.; Battistella, M.; Boldrin, M.; Brombin, M.; Dalla Palma, M.; De Lorenzi, A.; Delogu, R.; De Muri, M.; Fellin, F.; Ferro, A.; Fiorentin, A.; Gambetta, G.; Gnesotto, F.; Grando, L.; Jain, P.; Maistrello, A.; Manduchi, G.; Marconato, N.; Moresco, M.; Ocello, E.; Pavei, M.; Peruzzo, S.; Pilan, N.; Pimazzoni, A.; Recchia, M.; Rizzolo, A.; Rostagni, G.; Sartori, E.; Siragusa, M.; Sonato, P.; Sottocornola, A.; Spada, E.; Spagnolo, S.; Spolaore, M.; Taliercio, C.; Valente, M.; Veltri, P.; Zamengo, A.; Zaniol, B.; Zanotto, L.; Zaupa, M.; Boilson, D.; Graceffa, J.; Svensson, L.; Schunke, B.; Decamps, H.; Urbani, M.; Kushwah, M.; Chareyre, J.; Singh, M.; Bonicelli, T.; Agarici, G.; Garbuglia, A.; Masiello, A.; Paolucci, F.; Simon, M.; Bailly-Maitre, L.; Bragulat, E.; Gomez, G.; Gutierrez, D.; Mico, G.; Moreno, J.-F.; Pilard, V.; Kashiwagi, M.; Hanada, M.; Tobari, H.; Watanabe, K.; Maejima, T.; Kojima, A.; Umeda, N.; Yamanaka, H.; Chakraborty, A.; Baruah, U.; Rotti, C.; Patel, H.; Nagaraju, M. V.; Singh, N. P.; Patel, A.; Dhola, H.; Raval, B.; Fantz, U.; Heinemann, B.; Kraus, W.; Hanke, S.; Hauer, V.; Ochoa, S.; Blatchford, P.; Chuilon, B.; Xue, Y.; De Esch, H. P. L.; Hemsworth, R.; Croci, G.; Gorini, G.; Rebai, M.; Muraro, A.; Tardocchi, M.; Cavenago, M.; D'Arienzo, M.; Sandri, S.; Tonti, A.

2017-08-01

The ITER Neutral Beam Test Facility (NBTF), called PRIMA (Padova Research on ITER Megavolt Accelerator), is hosted in Padova, Italy and includes two experiments: MITICA, the full-scale prototype of the ITER heating neutral beam injector, and SPIDER, the full-size radio frequency negative-ions source. The NBTF realization and the exploitation of SPIDER and MITICA have been recognized as necessary to make the future operation of the ITER heating neutral beam injectors efficient and reliable, fundamental to the achievement of thermonuclear-relevant plasma parameters in ITER. This paper reports on design and R&D carried out to construct PRIMA, SPIDER and MITICA, and highlights the huge progress made in just a few years, from the signature of the agreement for the NBTF realization in 2011, up to now—when the buildings and relevant infrastructures have been completed, SPIDER is entering the integrated commissioning phase and the procurements of several MITICA components are at a well advanced stage.

Importance of helium-3 for the future

NASA Technical Reports Server (NTRS)

Kulcinski, Gerald L.

1989-01-01

Relevant plasma physics principles of thermonuclear research; the state of plasma physics as it pertains to the D-He(3) cycle; the technological benefits of the D-He(3) fuel cycle; the availability of He(3); and its location, methods of extraction and cost are discussed. A perspective on the rate of progress toward the goal of heating the confined plasma fuel to sufficiently high temperatures at high enough densities and for long enough times to cause substantial fusion of the atoms to take place is given in graphical form. The main technological advantages resulting from the D-He(3) fuel cycle, when compared with the DT cycle, are as follows: (1) increased electrical conversion efficiency; (2) reduced radiation damage to reactors; (3) reduced radioactive waste; (4) an increased level of safety in case of an accident; (5) the lower cost of electricity; and (6) the shorter time to commercialization. An account is given of mining He(3) on the Moon.

Pulsed Power Science and Technology: A Strategic Outlook for the National Nuclear Security Administration (Summary)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sinars, Daniel; Scott, Kimberly Carole; Edwards, M. John

Major advances in pulsed power technology and applications over the last twenty years have expanded the mission areas for pulsed power and created compelling new opportunities for the Stockpile Stewardship Program (SSP). This summary document is a forward look at the development of pulsed power science and technology (PPS&T) capabilities in support of the next 20 years of the SSP. This outlook was developed during a three-month-long tri-lab study on the future of PPS&T research and capabilities in support of applications to: (1) Dynamic Materials, (2) Thermonuclear Burn Physics and Inertial Confinement Fusion (ICF), and (3) Radiation Effects and Nuclearmore » Survivability. It also considers necessary associated developments in next-generation codes and pulsed power technology as well as opportunities for academic, industry, and international engagement. The document identifies both imperatives and opportunities to address future SSP mission needs. This study was commissioned by the National Nuclear Security Administration (NNSA). A copy of the memo request is contained in the Appendix. NNSA guidance received during this study explicitly directed that it not be constrained by resource limitations and not attempt to prioritize its findings against plans and priorities in other areas of the national weapons program. That prioritization, including the relative balance amongst the three focus areas themselves, must of course occur before any action is taken on the observations presented herein. This unclassified summary document presents the principal imperatives and opportunities identified in each mission and supporting area during this study. Preceding this area-specific outlook, we discuss a cross-cutting opportunity to increase the shot capacity on the Z pulsed power facility as a near-term, cost-effective way to broadly impact PPS&T for SSP as well as advancing the science and technology to inform future SSMP milestones over the next 5-10 years. The final page of the summary presents two timelines that couch the opportunities discussed here in terms of the broader strategic timelines encapsulated in the fiscal year 2017 Stockpile Stewardship Management Plan (SSMP).« less

Bumper wall for plasma device

DOEpatents

Coultas, Thomas A.

1977-01-01

Operation of a plasma device such as a reactor for controlled thermonuclear fusion is facilitated by an improved bumper wall enclosing the plasma to smooth the flow of energy from the plasma as the energy impinges upon the bumper wall. The bumper wall is flexible to withstand unequal and severe thermal shocks and it is readily replaced at less expense than the cost of replacing structural material in the first wall and blanket that surround it.

X-ray bursts: Observation versus theory

NASA Technical Reports Server (NTRS)

Lewin, W. H. G.

1981-01-01

Results of various observations of common type I X-ray bursts are discussed with respect to the theory of thermonuclear flashes in the surface layers of accreting neutron stars. Topics covered include burst profiles; irregular burst intervals; rise and decay times and the role of hydrogen; the accuracy of source distances; accuracy in radii determination; radius increase early in the burst; the super Eddington limit; temperatures at burst maximum; and the role of the magnetic field.

Alternative approaches to fusion. [reactor design and reactor physics for Tokamak fusion reactors

NASA Technical Reports Server (NTRS)

Roth, R. J.

1976-01-01

The limitations of the Tokamak fusion reactor concept are discussed and various other fusion reactor concepts are considered that employ the containment of thermonuclear plasmas by magnetic fields (i.e., stellarators). Progress made in the containment of plasmas in toroidal devices is reported. Reactor design concepts are illustrated. The possibility of using fusion reactors as a power source in interplanetary space travel and electric power plants is briefly examined.

Fusion Reactions and Matter-Antimatter Annihilation for Space Propulsion

DTIC Science & Technology

2005-07-13

shielding. λ D-3He eliminates the need for a complicated tritium-breeding blanked and tritium-processing system. 4 - MAGNETIC FUSION ENERGY (MFE...resulting specific powers. 5 - INERTIAL FUSION ENERGY (IFE) The possibility of igniting thermonuclear micro-explosions with pulsed laser beams was... fusion energy to antimatter rest mass energy, β, of 1.6 × 107. However, energy utilization is also lower due to the isotropic expansion process (ηe ~ 15

Plasmas in compact traps: From ion sources to multidisciplinary research

NASA Astrophysics Data System (ADS)

Mascali, D.; Musumarra, A.; Leone, F.; Galatà, A.; Romano, F. P.; Gammino, S.

2017-09-01

In linear (minimum-B) magneto-static traps dense and hot plasmas are heated by electromagnetic radiation in the GHz domain via the Electron Cyclotron Resonance (ECR). The values of plasma density, temperature and confinement times ( n_eτ_i>10^{13} cm ^{-3} s; T_e>10 keV) are similar to the ones of thermonuclear plasmas. The research in this field -devoted to heating and confinement optimization- has been supported by numerical modeling and advanced diagnostics, for probing the plasma especially in a non-invasive way. ECR-based systems are nowadays able to produce extremely intense (tens or hundreds of mA) beams of light ions (p, d, He), and relevant currents of heavier elements (C, O, N) up to heavy ions like Xe, Pb, U. Such beams can be extracted from the trap by a proper electrostatic system. The above-mentioned properties make these plasmas very attractive for interdisciplinary researches also, such as i) nuclear decays rates measurements in stellar-like conditions, ii) energy conversion studies, being exceptional sources of short-wavelength electromagnetic radiation (EUV, X-rays, hard X-rays and gammas, useful in material science and archaeometry), iii) environments allowing precise spectroscopical measurements as benchmarks for magnetized astrophysical plasmas. The talk will give an overview about the state-of-the-art in the field of intense ion sources, and some new perspectives for interdisciplinary research, with a special attention to the developments based at INFN-LNS.

Tritium proof-of-principle pellet injector: Phase 2

NASA Astrophysics Data System (ADS)

Fisher, P. W.; Gouge, M. J.

1995-03-01

As part of the International Thermonuclear Engineering Reactor (ITER) plasma fueling development program, Oak Ridge National Laboratory (ORNL) has fabricated a pellet injection system to test the mechanical and thermal properties of extruded tritium. This repeating, single-stage, pneumatic injector, called the Tritium-Proof-of-Principle Phase-2 (TPOP-2) Pellet Injector, has a piston-driven mechanical extruder and is designed to extrude hydrogenic pellets sized for the ITER device. The TPOP-II program has the following development goals: evaluate the feasibility of extruding tritium and DT mixtures for use in future pellet injection systems; determine the mechanical and thermal properties of tritium and DT extrusions; integrate, test and evaluate the extruder in a repeating, single-stage light gas gun sized for the ITER application (pellet diameter approximately 7-8 mm); evaluate options for recycling propellant and extruder exhaust gas; evaluate operability and reliability of ITER prototypical fueling systems in an environment of significant tritium inventory requiring secondary and room containment systems. In initial tests with deuterium feed at ORNL, up to thirteen pellets have been extruded at rates up to 1 Hz and accelerated to speeds of order 1.0-1.1 km/s using hydrogen propellant gas at a supply pressure of 65 bar. The pellets are typically 7.4 mm in diameter and up to 11 mm in length and are the largest cryogenic pellets produced by the fusion program to date. These pellets represent about a 11% density perturbation to ITER. Hydrogenic pellets will be used in ITER to sustain the fusion power in the plasma core and may be crucial in reducing first wall tritium inventories by a process called isotopic fueling where tritium-rich pellets fuel the burning plasma core and deuterium gas fuels the edge.

Investigation of heat transfer in liquid-metal flows under fusion-reactor conditions

NASA Astrophysics Data System (ADS)

Poddubnyi, I. I.; Pyatnitskaya, N. Yu.; Razuvanov, N. G.; Sviridov, V. G.; Sviridov, E. V.; Leshukov, A. Yu.; Aleskovskiy, K. V.; Obukhov, D. M.

2016-12-01

The effect discovered in studying a downward liquid-metal flow in vertical pipe and in a channel of rectangular cross section in, respectively, a transverse and a coplanar magnetic field is analyzed. In test blanket modules (TBM), which are prototypes of a blanket for a demonstration fusion reactor (DEMO) and which are intended for experimental investigations at the International Thermonuclear Experimental Reactor (ITER), liquid metals are assumed to fulfil simultaneously the functions of (i) a tritium breeder, (ii) a coolant, and (iii) neutron moderator and multiplier. This approach to testing experimentally design solutions is motivated by plans to employ, in the majority of the currently developed DEMO blanket projects, liquid metals pumped through pipes and/or rectangular channels in a transvers magnetic field. At the present time, experiments that would directly simulate liquid-metal flows under conditions of ITER TBM and/or DEMO blanket operation (irradiation with thermonuclear neutrons, a cyclic temperature regime, and a magnetic-field strength of about 4 to 10 T) are not implementable for want of equipment that could reproduce simultaneously the aforementioned effects exerted by thermonuclear plasmas. This is the reason why use is made of an iterative approach to experimentally estimating the performance of design solutions for liquid-metal channels via simulating one or simultaneously two of the aforementioned factors. Therefore, the investigations reported in the present article are of considerable topical interest. The respective experiments were performed on the basis of the mercury magneto hydrodynamic (MHD) loop that is included in the structure of the MPEI—JIHT MHD experimental facility. Temperature fields were measured under conditions of two- and one-sided heating, and data on averaged-temperature fields, distributions of the wall temperature, and statistical fluctuation features were obtained. A substantial effect of counter thermo gravitational convection (TGC) on averaged and fluctuating quantities were found. The development of TGC in the presence of a magnetic field leads to the appearance of low-frequency fluctuations whose anomalously high intensity exceeds severalfold the level of turbulence fluctuations. This effect manifest itself over a broad region of regime parameters. It was confirmed that low-energy fluctuations penetrate readily through the wall; therefore, it is necessary to study this effect further—in particular, from the point of view of the fatigue strength of the walls of liquid-metal channels.

Investigation of heat transfer in liquid-metal flows under fusion-reactor conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poddubnyi, I. I., E-mail: poddubnyyii@nikiet.ru; Pyatnitskaya, N. Yu.; Razuvanov, N. G.

2016-12-15

The effect discovered in studying a downward liquid-metal flow in vertical pipe and in a channel of rectangular cross section in, respectively, a transverse and a coplanar magnetic field is analyzed. In test blanket modules (TBM), which are prototypes of a blanket for a demonstration fusion reactor (DEMO) and which are intended for experimental investigations at the International Thermonuclear Experimental Reactor (ITER), liquid metals are assumed to fulfil simultaneously the functions of (i) a tritium breeder, (ii) a coolant, and (iii) neutron moderator and multiplier. This approach to testing experimentally design solutions is motivated by plans to employ, in themore » majority of the currently developed DEMO blanket projects, liquid metals pumped through pipes and/or rectangular channels in a transvers magnetic field. At the present time, experiments that would directly simulate liquid-metal flows under conditions of ITER TBM and/or DEMO blanket operation (irradiation with thermonuclear neutrons, a cyclic temperature regime, and a magnetic-field strength of about 4 to 10 T) are not implementable for want of equipment that could reproduce simultaneously the aforementioned effects exerted by thermonuclear plasmas. This is the reason why use is made of an iterative approach to experimentally estimating the performance of design solutions for liquid-metal channels via simulating one or simultaneously two of the aforementioned factors. Therefore, the investigations reported in the present article are of considerable topical interest. The respective experiments were performed on the basis of the mercury magneto hydrodynamic (MHD) loop that is included in the structure of the MPEI—JIHT MHD experimental facility. Temperature fields were measured under conditions of two- and one-sided heating, and data on averaged-temperature fields, distributions of the wall temperature, and statistical fluctuation features were obtained. A substantial effect of counter thermo gravitational convection (TGC) on averaged and fluctuating quantities were found. The development of TGC in the presence of a magnetic field leads to the appearance of low-frequency fluctuations whose anomalously high intensity exceeds severalfold the level of turbulence fluctuations. This effect manifest itself over a broad region of regime parameters. It was confirmed that low-energy fluctuations penetrate readily through the wall; therefore, it is necessary to study this effect further—in particular, from the point of view of the fatigue strength of the walls of liquid-metal channels.« less

Air concentrations of /sup 239/Pu and /sup 240/Pu and potential radiation doses to persons living near Pu-contaminated areas in Palomares, Spain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iranzo, E.; Salvador, S.; Iranzo, C.E.

1987-04-01

On 17 January 1966, an accident during a refueling operation resulted in the destruction of an air force KC-135 tanker and a B-52 bomber carrying four thermonuclear weapons. Two weapons, whose parachutes opened, were found intact. The others experienced non-nuclear explosion with some burning and release of the fissile fuel at impact. Joint efforts by the United States and Spain resulted in remedial action and a long-term program to monitor the effectiveness of the cleanup. Air concentrations of /sup 239/Pu and /sup 240/Pu have been continuously monitored since the accident. The average annual air concentration for each location was usedmore » to estimate committed dose equivalents for individuals living and working around the air sampling stations. The average annual /sup 239/Pu and /sup 240/Pu air concentrations during the 15-y period corresponding to 1966-1980 and the potential committed dose equivalents for various tissues due to the inhalation of the /sup 239/Pu and /sup 240/Pu average annual air concentration during this period are shown and discussed in the report.« less

Physics and technology of the arms race

NASA Astrophysics Data System (ADS)

Garwin, R. L.

1983-10-01

Traditional military concepts of superiority and effectiveness (as embodied in Lanchester's law) have little relevance to thermonuclear weapons, with their enormous effectiveness in destruction of society. Few are needed to saturate their deterrent effect, but their military effectiveness is limited. The evolution and future of strategic nuclear forces is discussed, and their declining marginal utility emphasized. Some calculatons relevant to the nuclear confrontation are presented (Lanchester's Law; skin effect of VLF and ELF signals to submarines; the rocket equation; simple radar-range equation) and recommendations presented for future strategic forces and arms control initiatives. Recommended programs include a silo-based 12-ton single-warhead missile (SICM), the development of buried-bomb defense of individual Minuteman silos, the completion of the deployment of air-launched cruise missiles on the B-52 fleet, and the development of small (1000-ton) submarines for basing ICBM-range missiles. Limiting the threat by arms control should include ratification of SALT II, followed by negotiation of a protrocool to allow a SICM and dedicated silo to be deployed for each two, SALT-II-allowed warheads given up; a ban on weapons in space and anti-satellite tests; and an eventual reduction to 1000 nuclear warheads in U.S. and Soviet inventories.

X-ray emission from high temperature plasmas

NASA Technical Reports Server (NTRS)

Harries, W. L.

1976-01-01

The physical processes occurring in plasma focus devices were studied. These devices produce dense high temperature plasmas, which emit X rays of hundreds of KeV energy and one to ten billion neutrons per pulse. The processes in the devices seem related to solar flare phenomena, and would also be of interest for controlled thermonuclear fusion applications. The high intensity, short duration bursts of X rays and neutrons could also possibly be used for pumping nuclear lasers.

JPRS Report, Soviet Union. USA: Economics, Politics, Ideology, No. 8, August 1987

DTIC Science & Technology

1988-02-03

the willingness to take the risk of thermonuclear war, and on the material level, by build- ing up strength. This kind of intimidation alone is...take certain actions on the grounds that the costs and risks of these actions outweigh the possible gains. But is the existence of rational thinking...will be unavoidably nullified by the constant threat of the unauthorized use of nuclear weapons with the risk of the escalation of an unprovoked

Imaging of high-energy x-ray emission from cryogenic thermonuclear fuel implosions on the NIF.

PubMed

Ma, T; Izumi, N; Tommasini, R; Bradley, D K; Bell, P; Cerjan, C J; Dixit, S; Döppner, T; Jones, O; Kline, J L; Kyrala, G; Landen, O L; LePape, S; Mackinnon, A J; Park, H-S; Patel, P K; Prasad, R R; Ralph, J; Regan, S P; Smalyuk, V A; Springer, P T; Suter, L; Town, R P J; Weber, S V; Glenzer, S H

2012-10-01

Accurately assessing and optimizing the implosion performance of inertial confinement fusion capsules is a crucial step to achieving ignition on the NIF. We have applied differential filtering (matched Ross filter pairs) to provide broadband time-integrated absolute x-ray self-emission images of the imploded core of cryogenic layered implosions. This diagnostic measures the temperature- and density-sensitive bremsstrahlung emission and provides estimates of hot spot mass, mix mass, and pressure.

Production of plasmas by long-wavelength lasers

DOEpatents

Dawson, J.M.

1973-10-01

A long-wavelength laser system for heating low-density plasma to high temperatures is described. In one embodiment, means are provided for repeatedly receiving and transmitting long-wavelength laser light in successive stages to form a laser-light beam path that repeatedly intersects with the equilibrium axis of a magnetically confined toroidal plasma column for interacting the laser light with the plasma for providing controlled thermonuclear fusion. Embodiments for heating specific linear plasmas are also provided. (Official Gazette)

A Waveguide Antenna with an Extended Angular Range for Remote Steering of Wave-Beam Direction

NASA Astrophysics Data System (ADS)

Sobolev, D. I.; Denisov, G. G.

2018-03-01

A new method for increasing the angular range of a waveguide antenna for remote steering of the wave-beam direction in thermonuclear-fusion experimental setups with plasma magnetic confinement is proposed. Characteristics for large beam inclination angles can be improved using the synthesized nonuniform waveguide profile. For small angles, the characteristics remain invariable, the waveguide profile differs only slightly from the regular shape, and can be fit to limited waveguide-channel sizes.

Direct conversion of nuclear radiation energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miley, George H.

1970-01-01

This book presents a comprehensive study of methods for converting nuclear radiationi directly without resorting to a heat cycle. The concepts discussed primarily involve direct collection of charged particles released by radioisotopes and by nuclear and thermonuclear reactors. Areas considered include basic energy conversion, charged-particle transport theory, secondary-electron emission, and leakage currents and associated problems. Applications to both nuclear instrumentaion and power sources are discussed. Problems are also included as an aid to the reader or for classroom use.

Stratospheric ozone - Fragile shield. [SST exhausts and Freons impact

NASA Technical Reports Server (NTRS)

Hoffert, M. I.; Stewart, R. W.

1975-01-01

Atmospheric models that have been used in major studies on the possible impact of SST exhausts and Freons on stratospheric ozone are discussed and compared. An overview is given of ozone-reduction estimates that they produce, together with an assessment of possible effects of atmospheric testing of thermonuclear bombs in an attempt to find direct observational evidence for ozone depletion resulting from human activities. It is concluded that clear validation of atmospheric-model predictions is lacking.

Simulation of the hohlraum for a laser facility of Megajoule scale

NASA Astrophysics Data System (ADS)

Chizhkov, M. N.; Kozmanov, M. Y. U.; Lebedev, S. N.; Lykov, V. A.; Rykovanova, V. V.; Seleznev, V. N.; Selezneva, K. I.; Stryakhnina, O. V.; Shestakov, A. A.; Vronskiy, A. V.

2010-08-01

2D calculations of the promising laser hohlraums were performed with using of the Sinara computer code. These hohlraums are intended for achievement of indirectly-driven thermonuclear ignition at laser energy above 1 MJ. Two calculation variants of the laser assembly with the form close to a rugby ball were carried out: with laser entrance hole shields and without shields. Time dependent hohlraum radiation temperature and x-ray flux asymmetry on a target were obtained.

Spectroscopic Study of Neon Z-Pinch Plasma for Sodium-Neon Photopumping Experiments

DTIC Science & Technology

1992-01-06

enhancement of the 11-A radiation from the n=4 level of neon when the sodium pump was present. For the 25-GV pump power, theoretical calculations predict...when the neon plasma is photopumped. Extensive theoretical analysis has been devoted to establishing the appropriate conditions for these plasmas. 5 ,44...producing thermonuclear neutrons. 63-65 Extensive theoretical modeling of the stability of these plasmas has guided this work.66 An imploding-liner Z

Process for recovering tritium from molten lithium metal

DOEpatents

Maroni, Victor A.

1976-01-01

Lithium tritide (LiT) is extracted from molten lithium metal that has been exposed to neutron irradiation for breeding tritium within a thermonuclear or fission reactor. The extraction is performed by intimately contacting the molten lithium metal with a molten lithium salt, for instance, lithium chloride - potassium chloride eutectic to distribute LiT between the salt and metal phases. The extracted tritium is recovered in gaseous form from the molten salt phase by a subsequent electrolytic or oxidation step.

OPERATION IVY. Report of Commander, Task Group 132.1. Pacific Proving Grounds. Joint Task Force 132

DTIC Science & Technology

1984-10-31

3.4.1 Device Planning One of the major purposes of Operation Greenhouse was to answer key questions relating to the possibility of developing...thermonuclear explosions. The Greenhouse George and Item Shots were Important steps in the investigation of basic problems in the development of a...January 1952, staff studies were made which were based on Greenhouse experience and on the best available estimates of the requirements pe- culiar to

Divertor impurity monitor for the International Thermonuclear Experimental Reactor

NASA Astrophysics Data System (ADS)

Sugie, T.; Ogawa, H.; Nishitani, T.; Kasai, S.; Katsunuma, J.; Maruo, M.; Ebisawa, K.; Ando, T.; Kita, Y.

1999-01-01

The divertor impurity monitoring system of the International Thermonuclear Experimental Reactor has been designed. The main functions of this system are to identify impurity species and to measure the two-dimensional distributions of the particle influxes in the divertor plasmas. The wavelength range is 200-1000 nm. The viewing fans are realized by molybdenum mirrors located in the divertor cassette. With additional viewing fans seeing through the gap between the divertor cassettes, the region approximately from the divertor leg to the x point will be observed. The light from the divertor region passes through the quartz windows on the divertor port plug and the cryostat, and goes through the dog-leg optics in the biological shield. Three different type of spectrometers: (i) survey spectrometers for impurity species monitoring, (ii) filter spectrometers for the particle influx measurement with the spatial resolution of 10 mm and the time resolution of 1 ms, and (iii) high dispersion spectrometers for high resolution wavelength measurements are designed. These spectrometers are installed just behind the biological shield (for λ<450 nm) to prevent the transmission loss in fiber and in the diagnostic room (for λ⩾450 nm) from the point of view of accessibility and flexibility. The optics have been optimized by a ray trace analysis. As a result, 10-15 mm spatial resolution will be achieved in all regions of the divertor.

A Classical Nova Explosion in a Binary System with B[e] Star

NASA Astrophysics Data System (ADS)

Filippova, E.; Revnivtsev, M.; Lutovinov, A.

2011-09-01

The description of a thermonuclear runaway on a white dwarf, which causes a Classical Nova (CN) explosion, has several uncertainties. Observational tests of models are challenging because the majority of CNe are observed in optical and NIR spectral bands days after the onset of the explosion. We propose to use the properties of the X-ray emission of CNe for these tests. We have developed a model for the 1998 CN explosion in the binary system CI Cam. According to the adopted model the stellar wind from the optical component (a B[e] star), heated by a strong shock wave that was produced when matter was ejected from the white dwarf as the result of a thermonuclear explosion on its surface, is the source of X-ray emission in the standard X-ray band (˜ 2 - 10 keV). We use this model to explain the behaviour of the X-ray luminosity and of the mean temperature of the heated material during the explosion, and obtain velocity and mass estimates of the ejected matter from the WD surface. Discrepancies between model and observations, for example the slower decline of the theoretical luminosity compared to the observed one, are likely caused by the rough assumption of spherical symmetry. Using 3D calculations we find possible density perturbations (accretion wakes) that can reconcile theory with observations.

Current drive for stability of thermonuclear plasma reactor

NASA Astrophysics Data System (ADS)

Amicucci, L.; Cardinali, A.; Castaldo, C.; Cesario, R.; Galli, A.; Panaccione, L.; Paoletti, F.; Schettini, G.; Spigler, R.; Tuccillo, A.

2016-01-01

To produce in a thermonuclear fusion reactor based on the tokamak concept a sufficiently high fusion gain together stability necessary for operations represent a major challenge, which depends on the capability of driving non-inductive current in the hydrogen plasma. This request should be satisfied by radio-frequency (RF) power suitable for producing the lower hybrid current drive (LHCD) effect, recently demonstrated successfully occurring also at reactor-graded high plasma densities. An LHCD-based tool should be in principle capable of tailoring the plasma current density in the outer radial half of plasma column, where other methods are much less effective, in order to ensure operations in the presence of unpredictably changes of the plasma pressure profiles. In the presence of too high electron temperatures even at the periphery of the plasma column, as envisaged in DEMO reactor, the penetration of the coupled RF power into the plasma core was believed for long time problematic and, only recently, numerical modelling results based on standard plasma wave theory, have shown that this problem should be solved by using suitable parameter of the antenna power spectrum. We show here further information on the new understanding of the RF power deposition profile dependence on antenna parameters, which supports the conclusion that current can be actively driven over a broad layer of the outer radial half of plasma column, thus enabling current profile control necessary for the stability of a reactor.

Thermonuclear targets for direct-drive ignition by a megajoule laser pulse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bel’kov, S. A.; Bondarenko, S. V.; Vergunova, G. A.

2015-10-15

Central ignition of a thin two-layer-shell fusion target that is directly driven by a 2-MJ profiled pulse of Nd laser second-harmonic radiation has been studied. The parameters of the target were selected so as to provide effective acceleration of the shell toward the center, which was sufficient for the onset of ignition under conditions of increased hydrodynamic stability of the ablator acceleration and compression. The aspect ratio of the inner deuterium-tritium layer of the shell does not exceed 15, provided that a major part (above 75%) of the outer layer (plastic ablator) is evaporated by the instant of maximum compression.more » The investigation is based on two series of numerical calculations that were performed using one-dimensional (1D) hydrodynamic codes. The first 1D code was used to calculate the absorption of the profiled laser-radiation pulse (including calculation of the total absorption coefficient with allowance for the inverse bremsstrahlung and resonance mechanisms) and the spatial distribution of target heating for a real geometry of irradiation using 192 laser beams in a scheme of focusing with a cubo-octahedral symmetry. The second 1D code was used for simulating the total cycle of target evolution under the action of absorbed laser radiation and for determining the thermonuclear gain that was achieved with a given target.« less

Neutron spectra from beam-target reactions in dense Z-pinches

NASA Astrophysics Data System (ADS)

Appelbe, B.; Chittenden, J.

2015-10-01

The energy spectrum of neutrons emitted by a range of deuterium and deuterium-tritium Z-pinch devices is investigated computationally using a hybrid kinetic-MHD model. 3D MHD simulations are used to model the implosion, stagnation, and break-up of dense plasma focus devices at currents of 70 kA, 500 kA, and 2 MA and also a 15 MA gas puff. Instabilities in the MHD simulations generate large electric and magnetic fields, which accelerate ions during the stagnation and break-up phases. A kinetic model is used to calculate the trajectories of these ions and the neutron spectra produced due to the interaction of these ions with the background plasma. It is found that these beam-target neutron spectra are sensitive to the electric and magnetic fields at stagnation resulting in significant differences in the spectra emitted by each device. Most notably, magnetization of the accelerated ions causes the beam-target spectra to be isotropic for the gas puff simulations. It is also shown that beam-target spectra can have a peak intensity located at a lower energy than the peak intensity of a thermonuclear spectrum. A number of other differences in the shapes of beam-target and thermonuclear spectra are also observed for each device. Finally, significant differences between the shapes of beam-target DD and DT neutron spectra, due to differences in the reaction cross-sections, are illustrated.

Vulnerability assessment of a space based weapon platform electronic system exposed to a thermonuclear weapon detonation

NASA Astrophysics Data System (ADS)

Perez, C. L.; Johnson, J. O.

Rapidly changing world events, the increased number of nations with inter-continental ballistic missile capability, and the proliferation of nuclear weapon technology will increase the number of nuclear threats facing the world today. Monitoring these nation's activities and providing an early warning and/or intercept system via reconnaissance and surveillance satellites and space based weapon platforms is a viable deterrent against a surprise nuclear attack. However, the deployment of satellite and weapon platform assets in space will subject the sensitive electronic equipment to a variety of natural and man-made radiation environments. These include Van Allen Belt protons and electrons; galactic and solar flare protons; and neutrons, gamma rays, and x-rays from intentionally detonated fission and fusion weapons. In this paper, the MASH vl.0 code system is used to estimate the dose to the critical electronics components of an idealized space based weapon platform from neutron and gamma-ray radiation emitted from a thermonuclear weapon detonation in space. Fluence and dose assessments were performed for the platform fully loaded, and in several stages representing limited engagement scenarios. The results indicate vulnerabilities to the Command, Control, and Communication bay instruments from radiation damage for a nuclear weapon detonation for certain source/platform orientations. The distance at which damage occurs will depend on the weapon yield (n,(gamma)/kiloton) and size (kilotons).

Fusion materials: Technical evaluation of the technology of vandium alloys for use as blanket structural materials in fusion power systems

NASA Astrophysics Data System (ADS)

1993-08-01

The Committee's evaluation of vanadium alloys as a structural material for fusion reactors was constrained by limited data and time. The design of the International Thermonuclear Experimental Reactor is still in the concept stage, so meaningful design requirements were not available. The data on the effect of environment and irradiation on vanadium alloys were sparse, and interpolation of these data were made to select the V-5Cr-5Ti alloy. With an aggressive, fully funded program it is possible to qualify a vanadium alloy as the principal structural material for the ITER blanket in the available 5 to 8-year window. However, the data base for V-5Cr-5Ti is limited and will require an extensive development and test program. Because of the chemical reactivity of vanadium the alloy will be less tolerant of system failures, accidents, and off-normal events than most other candidate blanket structural materials and will require more careful handling during fabrication of hardware. Because of the cost of the material more stringent requirements on processes, and minimal historical working experience, it will cost an order of magnitude to qualify a vanadium alloy for ITER blanket structures than other candidate materials. The use of vanadium is difficult and uncertain; therefore, other options should be explored more thoroughly before a final selection of vanadium is confirmed. The Committee views the risk as being too high to rely solely on vanadium alloys. In viewing the state and nature of the design of the ITER blanket as presented to the Committee, it is obvious that there is a need to move toward integrating fabrication, welding, and materials engineers into the ITER design team. If the vanadium alloy option is to be pursued, a large program needs to be started immediately. The commitment of funding and other resources needs to be firm and consistent with a realistic program plan.

MUCHFUSS: Status and Highlights

NASA Astrophysics Data System (ADS)

Geier, S.; Kupfer, T.; Barlow, B.; Schaffenroth, V.; Fürst, F.; Heuser, C.; Ziegerer, E.; Heber, U.; Marsh, T.; Maxted, P.; Östensen, R.; O'Toole, S.; Gänsicke, B.; Napiwotzki, R.

2014-04-01

The MUCHFUSS project aims at finding sdBs with massive compact companions. Here we report on the current status of our spectroscopic and photometric follow-up campaigns and present some highlight results. We derive orbital solutions of seven new sdB binaries and estimate the fraction of close substellar companions to sdBs. Finally, we present an ultracompact sdB+WD binary as possible progenitor of a thermonuclear supernova and connect it to the only known hypervelocity subdwarf star, which might be the donor remnant of such an event.

Inertial Confinement Fusion as an Extreme Example of Dynamic Compression

NASA Astrophysics Data System (ADS)

Moses, E.

2013-06-01

Initiating and controlling thermonuclear burn at the national ignition facility (NIF) will require the manipulation of matter to extreme energy densities. We will discuss recent advances in both controlling the dynamic compression of ignition targets and our understanding of the physical states and processes leading to ignition. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory in part under Contract W-7405-Eng-48 and in part under Contract DE-AC52-07NA27344.

Preliminary Failure Modes and Effects Analysis of the US DCLL Test Blanket Module

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee C. Cadwallader

2010-06-01

This report presents the results of a preliminary failure modes and effects analysis (FMEA) of a small tritium-breeding test blanket module design for the International Thermonuclear Experimental Reactor. The FMEA was quantified with “generic” component failure rate data, and the failure events are binned into postulated initiating event families and frequency categories for safety assessment. An appendix to this report contains repair time data to support an occupational radiation exposure assessment for test blanket module maintenance.

Preliminary Failure Modes and Effects Analysis of the US DCLL Test Blanket Module

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee C. Cadwallader

2007-08-01

This report presents the results of a preliminary failure modes and effects analysis (FMEA) of a small tritium-breeding test blanket module design for the International Thermonuclear Experimental Reactor. The FMEA was quantified with “generic” component failure rate data, and the failure events are binned into postulated initiating event families and frequency categories for safety assessment. An appendix to this report contains repair time data to support an occupational radiation exposure assessment for test blanket module maintenance.

Plasma control and utilization

DOEpatents

Ensley, Donald L.

1976-12-28

A plasma is confined and heated by a microwave field resonant in a cavity excited in a combination of the TE and TM modes while responding to the resonant frequency of the cavity as the plasma dimensions change to maintain operation at resonance. The microwave field is elliptically or circularly polarized as to prevent the electromagnetic confining field from going to zero. A high Q chamber having superconductive walls is employed to minimize wall losses while providing for extraction of thermonuclear energy produced by fusion of nuclei in the plasma.

Nuclear Coexistence: Rethinking U.S. Policy to Promote Stability in an Era of Proliferation

DTIC Science & Technology

1994-04-01

The Spread of Nuclear Weapons 1989 -90 (Boulder: Westview Press, 1990). 22. See William C. Martel and Steven E. Miller, "Controlling Borders and Nuclear...Security, Fall 1989 , Vol. 14, No. 2, pp. 140-41, for J. Robert Oppenheimer’s concerns about the dangers of the develop- ment of thermonuclear weapons. 4...Paradox of Technology," International Security, Vol. 14, No. 2 (Fall 1989 ), pp. 198-202. 6. Some argue that the U.S. strategy has relatively little

Science and technology review, July-August 1998 issue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smart, J

On the occasion of Edward Teller's 90th birthday, S&TR has the pleasure of honoring Lawrence Livermore's co-founder and most influential scientist. Teller is known for his inventive work in physics, his concepts leading to thermonuclear explosions, and his strong stands on such issues as science education, the nation's strategic defense, the needs for science in the future, and sharing scientific information. The articles in this issue also show him, as always, tirelessly moving forward with his new and changing interests.

Critical threshold behavior for steady-state internal transport barriers in burning plasmas.

PubMed

García, J; Giruzzi, G; Artaud, J F; Basiuk, V; Decker, J; Imbeaux, F; Peysson, Y; Schneider, M

2008-06-27

Burning tokamak plasmas with internal transport barriers are investigated by means of integrated modeling simulations. The barrier sustainment in steady state, differently from the barrier formation process, is found to be characterized by a critical behavior, and the critical number of the phase transition is determined. Beyond a power threshold, alignment of self-generated and noninductively driven currents occurs and steady state becomes possible. This concept is applied to simulate a steady-state scenario within the specifications of the International Thermonuclear Experimental Reactor.

Energies and transition rates in Ge-like ions between In XVIII and Ce XXVII

NASA Astrophysics Data System (ADS)

Chen, Zhan-Bin; Wang, Kai

2017-03-01

The energy levels, wavelengths, oscillator strengths, and radiative electric dipole (E1), magnetic quadrupole (M2) transition probabilities for Ge-like ions (49 ≤ Z ≤ 58) among the lowest 88 fine-structure levels belonging to the ([Ar] 3d10)4s24p2, ([Ar] 3d10)4s24p4d, ([Ar] 3d10)4s4p3, ([Ar] 3d10)4s4p24d, ([Ar] 3d10)4s24d2, and ([Ar] 3d10)4p4 configurations are calculated using the fully relativistic multiconfiguration Dirac-Fock (MCDF) approach including the correlations within the n = 7 complex, Breit interaction (BI) and quantum electrodynamics (QED) effects. For comparison, an independent calculation using the many-body perturbation theory (MBPT) method is also carried out to confirm the present energy levels accuracy, taking Xe XXIII as an example. The present results are compared with available experimental and theoretical results and good agreement is obtained. These accurate theoretical data are useful for controlled thermonuclear fusion research, plasma physics, and astrophysical applications.

Review of heat transfer problems associated with magnetically-confined fusion reactor concepts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoffman, M.A.; Werner, R.W.; Carlson, G.A.

1976-04-01

Conceptual design studies of possible fusion reactor configurations have revealed a host of interesting and sometimes extremely difficult heat transfer problems. The general requirements imposed on the coolant system for heat removal of the thermonuclear power from the reactor are discussed. In particular, the constraints imposed by the fusion plasma, neutronics, structure and magnetic field environment are described with emphasis on those aspects which are unusual or unique to fusion reactors. Then the particular heat transfer characteristics of various possible coolants including lithium, flibe, boiling alkali metals, and helium are discussed in the context of these general fusion reactor requirements.more » Some specific areas where further experimental and/or theoretical work is necessary are listed for each coolant along with references to the pertinent research already accomplished. Specialized heat transfer problems of the plasma injection and removal systems are also described. Finally, the challenging heat transfer problems associated with the superconducting magnets are reviewed, and once again some of the key unsolved heat transfer problems are enumerated.« less

A dual-PIXE tomography setup for reconstruction of Germanium in ICF target

NASA Astrophysics Data System (ADS)

Guo, N.; Lu, H. Y.; Wang, Q.; Meng, J.; Gao, D. Z.; Zhang, Y. J.; Liang, X. X.; Zhang, W.; Li, J.; Ma, X. J.; Shen, H.

2017-08-01

Inertial Confinement Fusion (ICF) is one type of fusion energy research which could initiate nuclear fusion reactions through heating and compressing thermonuclear fuel. Compared to a pure plastic target, Germanium doping into the CH ablator layer by Glow Discharge Polymer (GDP) technique can increase the ablation velocity and the standoff distance between the ablation front and laser-deposition region. During target fabrication process, quantitative doping of Ge should be accurately controlled. Particle Induced X-ray Emission Tomography (PIXE-T) can make not only quantification of the concentration, but also reconstruction of the spatial distribution of doped element. The Si (Li) detector for PIXE tomography technique had a disadvantage of low counting rate. To make up this deficiency, another detector of Si (Li) with the same configuration positioned at the opposite side with the same detective angle 135° have been implemented. Simultaneously acquired elemental maps of Ge obtained using two detectors may be different because of the X-ray absorption along the X-ray exit route in the target. In this paper, the X-ray detection efficiency is drastically improved by this dual-PIXE tomography system.

A Computational Study of a Circular Interface Richtmyer-Meshkov Instability in MHD

NASA Astrophysics Data System (ADS)

Maxon, William; Black, Wolfgang; Denissen, Nicholas; McFarland, Jacob; Los Alamos National Laboratory Collaboration; University of Missouri Shock Tube Laboratory Team

2017-11-01

The Richtmyer-Meshkov instability (RMI) is a hydrodynamic instability that appears in several high energy density applications such as inertial confinement fusion (ICF). In ICF, as the thermonuclear fuel is being compressed it begins to mix due to fluid instabilities including the RMI. This mixing greatly decreases the energy output. The RMI occurs when two fluids of different densities are impulsively accelerated and the pressure and density gradients are misaligned. In magnetohydrodynamics (MHD), the RMI may be suppressed by introducing a magnetic field in an electrically conducting fluid, such as a plasma. This suppression has been studied as a possible mechanism for improving confinement in ICF targets. In this study,ideal MHD simulations are performed with a circular interface impulsively accelerated by a shock wave in the presence of a magnetic field. These simulations are executed with the research code FLAG, a multiphysics, arbitrary Lagrangian/Eulerian, hydrocode developed and utilized at Los Alamos National Laboratory. The simulation results will be assessed both quantitatively and qualitatively to examine the stabilization mechanism. These simulations will guide ongoing MHD experiments at the University of Missouri Shock Tube Facility.

Robustness of waves with a high phase velocity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tajima, T., E-mail: ttajima@uci.edu; Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, CA 92688; Necas, A., E-mail: anecas@trialphaenergy.com

Norman Rostoker pioneered research of (1) plasma-driven accelerators and (2) beam-driven fusion reactors. The collective acceleration, coined by Veksler, advocates to drive above-ionization plasma waves by an electron beam to accelerate ions. The research on this, among others, by the Rostoker group incubated the idea that eventually led to the birth of the laser wakefield acceleration (LWFA), by which a large and robust accelerating collective fields may be generated in plasma in which plasma remains robust and undisrupted. Besides the emergence of LWFA, the Rostoker research spawned our lessons learned on the importance of adiabatic acceleration of ions in collectivemore » accelerators, including the recent rebirth in laser-driven ion acceleration efforts in a smooth adiabatic fashion by a variety of ingenious methods. Following Rostoker’s research in (2), the beam-driven Field Reversed Configuration (FRC) has accomplished breakthroughs in recent years. The beam-driven kinetic plasma instabilities have been found to drive the reactivity of deuteron-deuteron fusion beyond the thermonuclear yield in C-2U plasma that Rostoker started. This remarkable result in FRCs as well as the above mentioned LWFA may be understood with the aid of the newly introduced idea of the “robustness hypothesis of waves with a high phase velocity”. It posits that when the wave driven by a particle beam (or laser pulse) has a high phase velocity, its amplitude is high without disrupting the supporting bulk plasma. This hypothesis may guide us into more robust and efficient fusion reactors and more compact accelerators.« less

Impacts of Implosion Asymmetry And Hot Spot Shape On Ignition Capsules

NASA Astrophysics Data System (ADS)

Cheng, Baolian; Kwan, Thomas J. T.; Wang, Yi-Ming; Yi, S. Austin; Batha, Steve

2017-10-01

Implosion symmetry plays a critical role in achieving high areal density and internal energy at stagnation during hot spot formation in ICF capsules. Asymmetry causes hot spot irregularity and stagnation de-synchronization that results in lower temperatures and areal densities of the hot fuel. These degradations significantly affect the alpha heating process in the DT fuel as well as on the thermonuclear performance of the capsules. In this work, we explore the physical factors determining the shape of the hot spot late in the implosion and the effects of shape on Î+/-particle transport. We extend our ignition theory [1-4] to include the hot spot shape and quantify the effects of the implosion asymmetry on both the ignition criterion and capsule performance. We validate our theory with the NIF existing experimental data Our theory shows that the ignition criterion becomes more restrictive with the deformation of the hot spot. Through comparison with the NIF data, we demonstrate that the shape effects on the capsules' performance become more explicit as the self-heating and yield of the capsules increases. The degradation of the thermonuclear burn by the hot spot shape for high yield shots to date can be as high as 20%. Our theory is in good agreement with the NIF data. This work was performed under the auspices of the U.S. Department of Energy by the Los Alamos National Laboratory under Contract No. W-7405-ENG-36.

Synthesis of C-rich dust in CO nova outbursts

NASA Astrophysics Data System (ADS)

José, Jordi; Halabi, Ghina M.; El Eid, Mounib F.

2016-09-01

Context. Classical novae are thermonuclear explosions that take place in the envelopes of accreting white dwarfs in stellar binary systems. The material transferred onto the white dwarf piles up under degenerate conditions, driving a thermonuclear runaway. In these outbursts, about 10-7-10-3 M⊙, enriched in CNO and sometimes other intermediate-mass elements (e.g., Ne, Na, Mg, or Al for ONe novae) are ejected into the interstellar medium. The large concentrations of metals spectroscopically inferred in the nova ejecta reveal that the solar-like material transferred from the secondary mixes with the outermost layers of the underlying white dwarf. Aims: Most theoretical models of nova outbursts reported to date yield, on average, outflows characterized by O > C, from which, in principle, only oxidized condensates (e.g., O-rich grains) would be expected. Methods: To specifically address whether CO novae can actually produce C-rich dust, six different hydrodynamic nova models have been evolved, from accretion to the expansion and ejection stages, with different choices for the composition of the substrate with which the solar-like accreted material mixes. Updated chemical profiles inside the H-exhausted core have been used, based on stellar evolution calculations for a progenitor of 8 M⊙ through H- and He-burning phases. Results: We show that these profiles lead to C-rich ejecta after the nova outburst. This extends the possible contribution of novae to the inventory of presolar grains identified in meteorites, particularly in a number of carbonaceous phases (I.e., nanodiamonds, silicon carbides, and graphites).

The Spin Evolution of Fast-rotating, Magnetized Super-Chandrasekhar White Dwarfs in the Aftermath of White Dwarf Mergers

NASA Astrophysics Data System (ADS)

Becerra, L.; Rueda, J. A.; Lorén-Aguilar, P.; García-Berro, E.

2018-04-01

The evolution of the remnant of the merger of two white dwarfs is still an open problem. Furthermore, few studies have addressed the case in which the remnant is a magnetic white dwarf with a mass larger than the Chandrasekhar limiting mass. Angular momentum losses might bring the remnant of the merger to the physical conditions suitable for developing a thermonuclear explosion. Alternatively, the remnant may be prone to gravitational or rotational instabilities, depending on the initial conditions reached after the coalescence. Dipole magnetic braking is one of the mechanisms that can drive such losses of angular momentum. However, the timescale on which these losses occur depends on several parameters, like the strength of the magnetic field. In addition, the coalescence leaves a surrounding Keplerian disk that can be accreted by the newly formed white dwarf. Here we compute the post-merger evolution of a super-Chandrasekhar magnetized white dwarf taking into account all the relevant physical processes. These include magnetic torques acting on the star, accretion from the Keplerian disk, the threading of the magnetic field lines through the disk, and the thermal evolution of the white dwarf core. We find that the central remnant can reach the conditions suitable to develop a thermonuclear explosion before other instabilities (such as the inverse beta-decay instability or the secular axisymmetric instability) are reached, which would instead lead to gravitational collapse of the magnetized remnant.

Thermonuclear runaways in nova outbursts. 2: Effect of strong, instantaneous, local fluctuations

NASA Technical Reports Server (NTRS)

Shankar, Anurag; Arnett, David

1994-01-01

In an attempt to understand the manner in which nova outbursts are initiated on the surface of a white dwarf, we investigate the effects fluctuations have on the evolution of a thermonuclear runaway. Fluctuations in temperature density, or the composition of material in the burning shell may arise due to the chaotic flow field generated by convection when it occurs, or by the accretion process itself. With the aid of two-dimensional reactive flow calculations, we consider cases where a strong fluctutation in temperature arises during the early, quiescent accretion phase or during the later, more dynamic, explosion phase. In all cases we find that an instantaneous, local temperature fluctuation causes the affected material to become Rayleigh-Taylor unstable. The rapid rise and subsequent expansion of matter immediately cools the hot blob, which prevents the lateral propagation of burning. This suggests that local temperature fluctuations do not play a significant role in directly initiating the runaway, especially during the early stages. However, they may provide an efficient mechanism of mixing core material into the envelope (thereby pre-enriching the fuel for subsequent episodes of explosive hydrogen burning) and of mixing substantial amounts of the radioactive nucleus N-13 into the surface layers, making novae potential gamma-ray sources. This suggests that it is the global not the local, evolution of the core-envelope interface to high temperatures which dominates the development of the runaway. We also present a possible new scenario for the initiation of nova outbursts based on our results.

The relationship of thyroid cancer with radiation exposure from nuclear weapon testing in the Marshall Islands.

PubMed

Takahashi, Tatsuya; Schoemaker, Minouk J; Trott, Klaus R; Simon, Steven L; Fujimori, Keisei; Nakashima, Noriaki; Fukao, Akira; Saito, Hiroshi

2003-03-01

The US nuclear weapons testing program in the Pacific conducted between 1946 and 1958 resulted in radiation exposure in the Marshall Islands. The potentially widespread radiation exposure from radio-iodines of fallout has raised concerns about the risk of thyroid cancer in the Marshallese population. The most serious exposures and its health hazards resulted from the hydrogen-thermonuclear bomb test, the Castle BRAVO, on March 1, 1954. Between 1993 and 1997, we screened 3,709 Marshallese for thyroid disease who were born before the BRAVO test. It was 60% of the entire population at risk and who were still alive at the time of our examinations. We diagnosed 30 thyroid cancers and found 27 other study participants who had been operated for thyroid cancer before our screening in this group. Fifty-seven Marshallese born before 1954 (1.5%) had thyroid cancer or had been operated for thyroid cancer. Nearly all (92%) of these cancers were papillary carcinoma. We derived estimates of individual thyroid dose proxy from the BRAVO test in 1954 on the basis of published age-specific doses estimated on Utirik atoll and 137Cs deposition levels on the atolls where the participants came from. There was suggestive evidence that the prevalence of thyroid cancer increased with category of estimated dose to the thyroid.

Numerical Study of High Heat Flux Performances of Flat-Tile Divertor Mock-ups with Hypervapotron Cooling Concept

NASA Astrophysics Data System (ADS)

Chen, Lei; Liu, Xiang; Lian, Youyun; Cai, Laizhong

2015-09-01

The hypervapotron (HV), as an enhanced heat transfer technique, will be used for ITER divertor components in the dome region as well as the enhanced heat flux first wall panels. W-Cu brazing technology has been developed at SWIP (Southwestern Institute of Physics), and one W/CuCrZr/316LN component of 450 mm×52 mm×166 mm with HV cooling channels will be fabricated for high heat flux (HHF) tests. Before that a relevant analysis was carried out to optimize the structure of divertor component elements. ANSYS-CFX was used in CFD analysis and ABAQUS was adopted for thermal-mechanical calculations. Commercial code FE-SAFE was adopted to compute the fatigue life of the component. The tile size, thickness of tungsten tiles and the slit width among tungsten tiles were optimized and its HHF performances under International Thermonuclear Experimental Reactor (ITER) loading conditions were simulated. One brand new tokamak HL-2M with advanced divertor configuration is under construction in SWIP, where ITER-like flat-tile divertor components are adopted. This optimized design is expected to supply valuable data for HL-2M tokamak. supported by the National Magnetic Confinement Fusion Science Program of China (Nos. 2011GB110001 and 2011GB110004)

Numerical computation of gravitational field for general axisymmetric objects

NASA Astrophysics Data System (ADS)

Fukushima, Toshio

2016-10-01

We developed a numerical method to compute the gravitational field of a general axisymmetric object. The method (I) numerically evaluates a double integral of the ring potential by the split quadrature method using the double exponential rules, and (II) derives the acceleration vector by numerically differentiating the numerically integrated potential by Ridder's algorithm. Numerical comparison with the analytical solutions for a finite uniform spheroid and an infinitely extended object of the Miyamoto-Nagai density distribution confirmed the 13- and 11-digit accuracy of the potential and the acceleration vector computed by the method, respectively. By using the method, we present the gravitational potential contour map and/or the rotation curve of various axisymmetric objects: (I) finite uniform objects covering rhombic spindles and circular toroids, (II) infinitely extended spheroids including Sérsic and Navarro-Frenk-White spheroids, and (III) other axisymmetric objects such as an X/peanut-shaped object like NGC 128, a power-law disc with a central hole like the protoplanetary disc of TW Hya, and a tear-drop-shaped toroid like an axisymmetric equilibrium solution of plasma charge distribution in an International Thermonuclear Experimental Reactor-like tokamak. The method is directly applicable to the electrostatic field and will be easily extended for the magnetostatic field. The FORTRAN 90 programs of the new method and some test results are electronically available.

Test facility for investigation of heat transfer of promising coolants for the nuclear power industry

NASA Astrophysics Data System (ADS)

Belyaev, I. A.; Sviridov, V. G.; Batenin, V. M.; Biryukov, D. A.; Nikitina, I. S.; Manchkha, S. P.; Pyatnitskaya, N. Yu.; Razuvanov, N. G.; Sviridov, E. V.

2017-11-01

The results are presented of experimental investigations into liquid metal heat transfer performed by the joint research group consisting of specialist in heat transfer and hydrodynamics from NIU MPEI and JIHT RAS. The program of experiments has been prepared considering the concept of development of the nuclear power industry in Russia. This concept calls for, in addition to extensive application of water-cooled, water-moderated (VVER-type) power reactors and BN-type sodium cooled fast reactors, development of the new generation of BREST-type reactors, fusion power reactors, and thermonuclear neutron sources. The basic coolants for these nuclear power installations will be heavy liquid metals, such as lead and lithium-lead alloy. The team of specialists from NRU MPEI and JIHT RAS commissioned a new RK-3 mercury MHD-test facility. The major components of this test facility are a unique electrical magnet constructed at Budker Nuclear Physics Institute and a pressurized liquid metal circuit. The test facility is designed for investigating upward and downward liquid metal flows in channels of various cross-sections in a transverse magnetic field. A probe procedure will be used for experimental investigation into heat transfer and hydrodynamics as well as for measuring temperature, velocity, and flow parameter fluctuations. It is generally adopted that liquid metals are the best coolants for the Tokamak reactors. However, alternative coolants should be sought for. As an alternative to liquid metal coolants, molten salts, such as fluorides of lithium and beryllium (so-called FLiBes) or fluorides of alkali metals (so-called FLiNaK) doped with uranium fluoride, can be used. That is why the team of specialists from NRU MPEI and JIHT RAS, in parallel with development of a mercury MHD test facility, is designing a test facility for simulating molten salt heat transfer and hydrodynamics. Since development of this test facility requires numerical predictions and verification of numerical codes, all examined configurations of the MHD flow are also investigated numerically.

An Adaptive QSE-reduced Nuclear Reaction Network for Silicon Burning

NASA Astrophysics Data System (ADS)

Parete-Koon, Suzanne; Hix, W.; Thielemann, F.

2008-03-01

The nuclei of the "iron peak" are formed in massive stars shortly before core collapse and during their supernova outbursts as well as during thermonuclear supernovae. Complete and incomplete silicon burning during these events are responsible for the production of a wide range of nuclei with atomic mass numbers from 28 to 64. Because of the large number of nuclei involved, accurate modeling of silicon burning is computationally expensive. However, examination of the physics of silicon burning has revealed that the nuclear evolution is dominated by large groups of nuclei in mutual equilibrium. We present an improvement on our hybrid equilibrium-network scheme which takes advantage of this quasi-equilibrium in order to reduce the number of independent variables calculated. Because the size and membership of these groups vary as the temperature, density and electron faction change, achieving maximal efficiency requires dynamic adjustment of group number and membership. Toward this end, we are implementing a scheme beginning with a single QSE (NSE) group at appropriately high temperature, then progressing through 2, 3 and 4 group stages (with successively more independent variables) as temperature declines. This combination allows accurate prediction of the nuclear abundance evolution, deleptonization and energy generation at a further reduced computational cost when compared to a conventional nuclear reaction network or our previous 3 fixed group QSE-reduced network. During silicon burning, the resultant QSE-reduced network is up to 20 times faster than the full network it replaces without significant loss of accuracy. These reductions in computational cost and the number of species evolved make QSE-reduced networks well suited for inclusion within hydrodynamic simulations, particularly in multi-dimensional applications. This work has been supported by the National Science Foundation, by the Department of Energy's Scientic Discovery through Advanced Computing Programs, and by the Joint Institute for Heavy Ion Research at ORNL.

High School Students Watching Stars Evolve

NASA Astrophysics Data System (ADS)

Percy, J. R.; MacNeil, D.; Meema-Coleman, L.; Morenz, K.

2012-06-01

(Abstract only) Some stars pulsate (vibrate). Their pulsation period depends primarily on their radius. The pulsation period changes if the radius changes, due to evolution, for instance. Even though the evolution is slow, the period change is measurable because it is cumulative. The observed time of maximum brightness (O) minus the calculated time (C), assuming that the period is constant, is plotted against time to produce an (O-C) diagram. If there is a uniform period change, this diagram will be a parabola, whose curvature - positive or negative - is proportional to the rate of period change. In this project, we study the period changes of RR Lyrae stars, old sun-like stars which are in the yellow giant phase, generating energy by thermonuclear fusion of helium into carbon. We chose 59 well-studied stars in the GEOS database, which consists of times of maximum measured by AAVSO and other observers. We included about a dozen RRc (first overtone pulsator) stars, since these have not been as well studied as the RRab (fundamental mode) stars because the maxima in their light curves are not as sharp. We will describe our results: about 2/3 of the stars showed parabolic (O-C) diagrams with period changes of up to 1.0 s/century, some with increasing periods and some with decreasing periods. The characteristic times for period changes (i.e. period divided by rate of change of period) were mostly 5-30 million years. These numbers are consistent with evolutionary models. Some stars showed too much scatter for analysis; we will discuss why. A few stars showed unusual (O-C) diagrams which cannot be explained simply by evolution. This project was carried out by coauthors MacNeil, Meema-Coleman, and Morenz, who were participants in the prestigious University of Toronto Mentorship Program, which enables outstanding senior high school students to participate in research at the university. We thank the AAVSO and other observers who made the measurements which were used in our project.

Swift/XRT detects a new accretion outburst of the Galactic center neutron star transient GRS 1741-2853

NASA Astrophysics Data System (ADS)

Degenaar, N.; Wijnands, R.; Reynolds, M. T.; Miller, J. M.; Kennea, J. A.

2017-10-01

Daily Swift/XRT monitoring observations of the Galactic center (Degenaar et al. 2015) have picked up renewed activity of the transient neutron star low-mass X-ray binary and thermonuclear X-ray burster GRS 1741-2853, which is located 10 arcmin NW of Sgr A*. During a 1 ks PC-mode observation performed on 2017 October 11 the source is detected at a net count rate of 0.015 counts/s and it has been steadily brightening since, indicating the onset of a new accretion outburst.

Sir Fred Hoyle and the theory of the synthesis of the elements

NASA Astrophysics Data System (ADS)

Arnett, David

Some of Fred Hoyle's pioneering ideas about the site and the nature of the synthesis of the elements are examined in a modern context of theory, experiment and observations. Hoyle's ideas concerning the nucleosynthesis cycle of stellar birth and death, rotational instability of supernovae, the onion-skin model of presupernovae, neutronization, nuclear statistical equilibrium and core collapse, thermonuclear supernovae, nucleosynthesis processes and freeze-out are discussed. The history of the clash of theory and experiment on the second excited state of 8Be and helium ignition in red giants is reviewed.

Characterization of the ITER model negative ion source during long pulse operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hemsworth, R.S.; Boilson, D.; Crowley, B.

2006-03-15

It is foreseen to operate the neutral beam system of the International Thermonuclear Experimental Reactor (ITER) for pulse lengths extending up to 1 h. The performance of the KAMABOKO III negative ion source, which is a model of the source designed for ITER, is being studied on the MANTIS test bed at Cadarache. This article reports the latest results from the characterization of the ion source, in particular electron energy distribution measurements and the comparison between positive ion and negative ion extraction from the source.

Thermoelectric generator with hinged assembly for fins

DOEpatents

Purdy, David L.; Shapiro, Zalman M.; Hursen, Thomas F.; Maurer, Gerould W.

1976-11-02

A cylindrical casing has a central shielded capsule of radioisotope fuel. A plurality of thermonuclear modules are axially arranged with their hot junctions resiliently pressed toward the shield and with their cold junctions adjacent a transition member having fins radiating heat to the environment. For each module, the assembly of transition member and fins is hinged to the casing for swinging to permit access to and removal of such module. A ceramic plate having gold layers on opposite faces prevents diffusion bonding of the hot junction to the shield.

Macromolecular Networks Containing Fluorinated Cyclic Moieties

DTIC Science & Technology

2015-12-12

Approved for public release.  Distribution is unlimited.   Cyanate Esters Around the Solar System 4 Images:  courtesy  NASA  (public release) • The...science decks on the Mars Phoenix lander are made from M55J/cyanate ester composites • The solar panel supports on the MESSENGER space probe use cyanate...thermonuclear fusion reactor Fusion reactor, photo  courtesy of Gerritse ((Wikimedia Commons) • Unique cyanate ester composites have been designed by NASA

The LUNA experiment at Gran Sasso Laboratory: Studying stars by going underground

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guglielmetti, Alessandra

2015-10-15

Accurate knowledge of thermonuclear reaction rates is a key issue in nuclear astrophysics: it is important for understanding the energy generation, neutrino production and the synthesis of the elements in stars and during primordial nucleosynthesis. Cross-section measurements are mainly hampered by the very low counting rate and cosmic background. An underground location is extremely advantageous for such studies, as demonstrated by the LUNA experiment in the Gran Sasso Laboratory (Italy). This paper reports on the results recently obtained by this experiment and on the future perspectives in the field.

Supernova explosions.

NASA Technical Reports Server (NTRS)

Cameron, A. G. W.

1971-01-01

The recent history of theoretical investigations of the supernova mechanism is considered, giving attention also to a number of nuclear physical problems which have yet to be solved in connection with the thermonuclear detonation. A variety of different processes of nucleo-synthesis are expected to occur in association with the supernova explosions. Aspects of the chemical evolution of the galaxy are discussed including the cosmic ray production of lithium, beryllium, and boron in the interstellar medium. Various hypotheses to account for the very large amount of light that comes from a supernova explosion are also examined.

Bottlenecks and Waiting Points in Nucleosynthesis in X-ray bursts and Novae

NASA Astrophysics Data System (ADS)

Smith, Michael S.; Sunayama, Tomomi; Hix, W. Raphael; Lingerfelt, Eric J.; Nesaraja, Caroline D.

2010-08-01

To better understand the energy generation and element synthesis occurring in novae and X-ray bursts, we give quantitative definitions to the concepts of ``bottlenecks'' and ``waiting points'' in the thermonuclear reaction flow. We use these criteria to search for bottlenecks and waiting points in post-processing element synthesis explosion simulations. We have incorporated these into the Computational Infrastructure for Nuclear Astrophysics, a suite of nuclear astrophysics codes available online at nucastrodata.org, so that anyone may perform custom searches for bottlenecks and waiting points.

Foam encapsulated targets

DOEpatents

Nuckolls, John H.; Thiessen, Albert R.; Dahlbacka, Glen H.

1983-01-01

Foam encapsulated laser-fusion targets wherein a quantity of thermonuclear fuel is embedded in low density, microcellular foam which serves as an electron conduction channel for symmetrical implosion of the fuel by illumination of the target by one or more laser beams. The fuel, such as DT, is contained within a hollow shell constructed of glass, for example, with the foam having a cell size of preferably no greater than 2 .mu.m, a density of 0.065 to 0.6.times.10.sup.3 kg/m.sup.3, and external diameter of less than 200 .mu.m.

Electron-ion relaxation in a dense plasma. [supernovae core physics

NASA Technical Reports Server (NTRS)

Littleton, J. E.; Buchler, J.-R.

1974-01-01

The microscopic physics of the thermonuclear runaway in highly degenerate carbon-oxygen cores is investigated to determine if and how a detonation wave is generated. An expression for the electron-ion relaxation time is derived under the assumption of large degeneracy and extreme relativity of the electrons in a two-temperature plasma. Since the nuclear burning time proves to be several orders of magnitude shorter than the relaxation time, it is concluded that in studying the structure of the detonation wave the electrons and ions must be treated as separate fluids.

Release and Movement of Radionuclides in Soils Contaminated with Fallout Materials from an Underground Thermonuclear Detonation

DTIC Science & Technology

1962-07-06

Studies The degree of dissolution of the fallout material in H2 0, HCl, DTPA, CDTA, and EDDHA solutions was investigated by the suspension method...days was: EDDHA >DTPA>CDTA>H 2 0. while after 65 days the order of effect was: CDTA> EDDHA >DTPA>H 20. Portions of gamma ray spectra of the 106 day...the same amounts of radionuclides as did H120. The most abundant radio- nuclide was radiotungsten for H120, DTPA, CDTA, and EDDHA supernatant liquids

Bottlenecks and Waiting Points in Nucleosynthesis in X-ray bursts and Novae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Michael S.; Hix, W. Raphael; Nesaraja, Caroline D.

2010-08-12

To better understand the energy generation and element synthesis occurring in novae and X-ray bursts, we give quantitative definitions to the concepts of ''bottlenecks'' and ''waiting points'' in the thermonuclear reaction flow. We use these criteria to search for bottlenecks and waiting points in post-processing element synthesis explosion simulations. We have incorporated these into the Computational Infrastructure for Nuclear Astrophysics, a suite of nuclear astrophysics codes available online at nucastrodata.org, so that anyone may perform custom searches for bottlenecks and waiting points.

ELECTRICAL COIL STRUCTURE

DOEpatents

Baker, W.R.; Hartwig, A.

1962-09-25

A compactly wound electrical coil is designed for carrying intense pulsed currents such as are characteristic of controlled thermonuclear reaction devices. A flat strip of conductor is tightly wound in a spiral with a matching flat strip of insulator. To provide for a high fluid coolant flow through the coil with minimum pumping pressure, a surface of the conductor is scored with parallel transverse grooves which form short longitudinal coolant pasaages when the conductor is wound in the spiral configuration. Owing to this construction, the coil is extremely resistant to thermal and magnetic shock from sudden high currents. (AEC)

Impact of Space Exploration on Biology and Medicine

NASA Technical Reports Server (NTRS)

Randt, Clark T.

1960-01-01

Basic human drives for pioneering and conquest can find acceptable expression in extraterrestrial exploration. It is unmistakably clear that our civilization cannot survive a thermonuclear conflict. The expression of aggressive drives in war has repeatedly supplied an impetus for unusual increments in the growth of the arts and sciences.. A historical review of intellectual progress and concomitant technological advance gives reason to expect that expanded knowledge of the universe will produce an unprecedented burst of creative activity in biology and medicine as well as in the physical sciences and engineering.

Science and Technology Review, July-August 1998: Celebrating Edward Teller at 90

DOE R&D Accomplishments Database

Smart, J.

1998-07-01

On the occasion of Edward Teller's 90th birthday, Science and Technology Review (S&TR) has the pleasure of honoring Lawrence Livermore's co-founder and most influential scientist. Teller is known for his inventive work in physics, his concepts leading to thermonuclear explosions, and his strong stands on such issues as science education, the nation's strategic defense, the needs for science in the future, and sharing scientific information. The articles in this issue also show him, as always, tirelessly moving forward with his new and changing interests.

Role of the ''fountain effect'' in the equatorial ionosphere in the prolonged retention of radioactive products of the ''Starfish'' explosion at F-region altitudes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bolyunova, A.D.

1975-01-01

The effect of prolonged retention of radioactive products (fission fragments) following the ''Starfish'' thermonuclear explosion at F-region altitudes of the ionosphere of lower and middle latitudes discovered on the Kosmos 3, Kosmos 5, and Kosmos 6 satellites is analyzed from the point of view of concepts concerning ion transport processes in the equatorial ionosphere. A qualitative explanation for this phenomenon based on the ''fountain effect'' in the equatorial ionosphere is proposed which is in satisfactory agreement with experiment.

Matching an Inductive Accumulator and a System of Acceleration of a Liner with Limitation of the Breaking Voltage,

DTIC Science & Technology

In this work calculations are made of the efficiencies of acceleration of a liner from an inductive accumulator in the mode theta-pinch and Z-pinch...to the speed of the liner . Estimations have been made of the necessary power at the moment of switching the current on the basis of considerations of...the stability of the pinch effect of the liner . The level of energies necessary for the creation of a thermonuclear reactor on the basis of theta

Simulations of High-Gain Shock-Ignited Inertial-Confinement-Fusion Implosions Using Less Than 1 MJ of Direct KrF Laser Energy

DTIC Science & Technology

2009-05-01

transport, and thermonuclear burn. Using FAST, three classes of shock-ignited targets were designed that achieve one-dimensional fusion - energy gains in the...MJ) G a in Figure 1: Results of one-dimensional simulations showing the fusion energy gain as a function of KrF laser energy for three classes of...rises smoothly (according to a double power (a) Spike width: 160 ps (b) Spike power: 1530 TW Figure 4: Examples of fusion - energy gain contours for a shock

NICER Detection of Strong Photospheric Expansion during a Thermonuclear X-Ray Burst from 4U 1820–30

NASA Astrophysics Data System (ADS)

Keek, L.; Arzoumanian, Z.; Chakrabarty, D.; Chenevez, J.; Gendreau, K. C.; Guillot, S.; Güver, T.; Homan, J.; Jaisawal, G. K.; LaMarr, B.; Lamb, F. K.; Mahmoodifar, S.; Markwardt, C. B.; Okajima, T.; Strohmayer, T. E.; in ’t Zand, J. J. M.

2018-04-01

The Neutron Star Interior Composition Explorer (NICER) on the International Space Station (ISS) observed strong photospheric expansion of the neutron star in 4U 1820–30 during a Type I X-ray burst. A thermonuclear helium flash in the star’s envelope powered a burst that reached the Eddington limit. Radiation pressure pushed the photosphere out to ∼200 km, while the blackbody temperature dropped to 0.45 keV. Previous observations of similar bursts were performed with instruments that are sensitive only above 3 keV, and the burst signal was weak at low temperatures. NICER's 0.2–12 keV passband enables the first complete detailed observation of strong expansion bursts. The strong expansion lasted only 0.6 s, and was followed by moderate expansion with a 20 km apparent radius, before the photosphere finally settled back down at 3 s after the burst onset. In addition to thermal emission from the neutron star, the NICER spectra reveal a second component that is well fit by optically thick Comptonization. During the strong expansion, this component is six times brighter than prior to the burst, and it accounts for 71% of the flux. In the moderate expansion phase, the Comptonization flux drops, while the thermal component brightens, and the total flux remains constant at the Eddington limit. We speculate that the thermal emission is reprocessed in the accretion environment to form the Comptonization component, and that changes in the covering fraction of the star explain the evolution of the relative contributions to the total flux.

Study of Volumetrically Heated Ultra-High Energy Density Plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rocca, Jorge J.

2016-10-27

Heating dense matter to millions of degrees is important for applications, but requires complex and expensive methods. The major goal of the project was to demonstrate using a compact laser the creation of a new ultra-high energy density plasma regime characterized by simultaneous extremely high temperature and high density, and to study it combining experimental measurements and advanced simulations. We have demonstrated that trapping of intense femtosecond laser pulses deep within ordered nanowire arrays can heat near solid density matter into a new ultra hot plasma regime. Extreme electron densities, and temperatures of several tens of million degrees were achievedmore » using laser pulses of only 0.5 J energy from a compact laser. Our x-ray spectra and simulations showed that extremely highly ionized plasma volumes several micrometers in depth are generated by irradiation of gold and Nickel nanowire arrays with femtosecond laser pulses of relativistic intensities. We obtained extraordinarily high degrees of ionization (e.g. we peeled 52 electrons from gold atoms, and up to 26 electrons from nickel atoms). In the process we generated Gigabar pressures only exceeded in the central hot spot of highly compressed thermonuclear fusion plasmas.. The plasma created after the dissolved wires expand, collide, and thermalize, is computed to have a thermal energy density of 0.3 GJ cm -3 and a pressure of 1-2 Gigabar. These are pressures only exceeded in highly compressed thermonuclear fusion plasmas. Scaling these results to higher laser intensities promises to create plasmas with temperatures and pressures exceeding those in the center of the sun.« less

Uncertainties in the production of p nuclides in thermonuclear supernovae determined by Monte Carlo variations

NASA Astrophysics Data System (ADS)

Nishimura, N.; Rauscher, T.; Hirschi, R.; Murphy, A. St J.; Cescutti, G.; Travaglio, C.

2018-03-01

Thermonuclear supernovae originating from the explosion of a white dwarf accreting mass from a companion star have been suggested as a site for the production of p nuclides. Such nuclei are produced during the explosion, in layers enriched with seed nuclei coming from prior strong s processing. These seeds are transformed into proton-richer isotopes mainly by photodisintegration reactions. Several thousand trajectories from a 2D explosion model were used in a Monte Carlo approach. Temperature-dependent uncertainties were assigned individually to thousands of rates varied simultaneously in post-processing in an extended nuclear reaction network. The uncertainties in the final nuclear abundances originating from uncertainties in the astrophysical reaction rates were determined. In addition to the 35 classical p nuclides, abundance uncertainties were also determined for the radioactive nuclides 92Nb, 97, 98Tc, 146Sm, and for the abundance ratios Y(92Mo)/Y(94Mo), Y(92Nb)/Y(92Mo), Y(97Tc)/Y(98Ru), Y(98Tc)/Y(98Ru), and Y(146Sm)/Y(144Sm), important for Galactic Chemical Evolution studies. Uncertainties found were generally lower than a factor of 2, although most nucleosynthesis flows mainly involve predicted rates with larger uncertainties. The main contribution to the total uncertainties comes from a group of trajectories with high peak density originating from the interior of the exploding white dwarf. The distinction between low-density and high-density trajectories allows more general conclusions to be drawn, also applicable to other simulations of white dwarf explosions.

Variable spreading layer in 4U 1608-52 during thermonuclear X-ray bursts in the soft state

NASA Astrophysics Data System (ADS)

Kajava, J. J. E.; Koljonen, K. I. I.; Nättilä, J.; Suleimanov, V.; Poutanen, J.

2017-11-01

Thermonuclear (type-I) X-ray bursts, observed from neutron star (NS) low-mass X-ray binaries (LMXB), provide constraints on NS masses and radii and consequently the equation of state of NS cores. In such analyses, various assumptions are made without knowing if they are justified. We have analysed X-ray burst spectra from the LMXB 4U 1608-52, with the aim of studying how the different persistent emission components react to the bursts. During some bursts in the soft spectral state we find that there are two variable components: one corresponding to the burst blackbody component and another optically thick Comptonized component. We interpret the latter as the spreading layer between the NS surface and the accretion disc, which is not present during the hard-state bursts. We propose that the spectral changes during the soft-state bursts are driven by the spreading layer that could cover almost the entire NS in the brightest phases due to the enhanced radiation pressure support provided by the burst, and that the layer subsequently returns to its original state during the burst decay. When deriving the NS mass and radius using the soft-state bursts two assumptions are therefore not met: the NS is not entirely visible and the burst emission is reprocessed in the spreading layer, causing distortions of the emitted spectrum. For these reasons, the NS mass and radius constraints using the soft-state bursts are different compared to the ones derived using the hard-state bursts.

High-precision Location, Yield and Tectonic Release of North Korea's 3 September 2017 Nuclear Test

NASA Astrophysics Data System (ADS)

Yao, J.; Tian, D.; Wen, L.

2017-12-01

On 3 September 2017, the Democratic People's Republic of Korea (North Korea) announced that it had successfully conducted a thermonuclear (hydrogen bomb) test. The nuclear test was collaborated by reports of a seismic event with a magnitude ranging from 6.1 to 6.3 by many governmental and international agencies, although its thermonuclear nature remains to be confirmed. In this study, by combining modern methods of high-precision relocation and satellite imagery, and using the knowledge of a previous test (North Korea's 9 September 2016 test) as reference, we determine the location and yield of North Korea's 2017 test. The location of the 2017 test is determined by deriving relative location between North Korea's 2017 and 2016 nuclear tests and using the previously determined location of the 2016 nuclear test by our group, while its yield is estimated based on the relative amplitude ratios of the Lg waves recorded for both events, the previously determined Lg-magnitude of the 2016 test and burial depth inferred from satellite imagery. The 2017 nuclear test is determined to be located at (41° 17' 53.52″ N, 129° 4' 27.12″ E) with a geographic precision of 100 m, and its yield is estimated to be 108±48 kt. The 2017 nuclear test and its four previous tests since 2009 are located several hundred meters apart, beneath the same mountain Mantap. We also evaluate the tectonic release by the 2017 nuclear test and discuss its implications for the yield estimation of the test.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Remming, Ian S.; Khokhlov, Alexei M.

We present general equations for non-ideal, reactive flow magnetohydrodynamics (RFMHD) in the form best suited for describing thermonuclear combustion in high-density degenerate matter of SNe Ia. The relative importance of various non-ideal effects is analyzed as a function of characteristic spatial and temporal scales of the problem. From the general RFMHD equations, we derive the one-dimensional ordinary differential equations describing the steady-state propagation of a planar thermonuclear flame front in a magnetic field. The physics of the flame is first studied qualitatively using a simple case of one-step Arrhenius kinetics, a perfect gas equation of state (EOS), and constant thermalmore » conductivity coefficients. After that, the equations are solved, the internal flame front structure is calculated, and the flame velocity, S {sub l} , and flame thickness, δ {sub l} , are found for carbon–oxygen degenerate material of supernovae using a realistic EOS, transport properties, and detailed nuclear kinetics. The magnetic field changes the flame behavior significantly, both qualitatively and quantitatively, as compared to the non-magnetic case of classical combustion. (1) The magnetic field influences the evolutionarity of a flame front and makes it impossible for a flame to propagate steadily in a wide range of magnetic field strengths and orientations relative to the front. (2) When the flame moves steadily, it can propagate in several distinct modes, the most important being the slow C {sub S} and super-Alfvénic C {sub sup} modes. (3) The speed of the flame can be diminished or enhanced by up to several factors relative to the non-magnetic laminar flame speed.« less

X-Ray Reflection and an Exceptionally Long Thermonuclear Helium Burst from IGR J17062-6143

NASA Technical Reports Server (NTRS)

Keek, L.; Iwakiri, W.; Serino, M.; Ballantyne, D. R.; in’t Zand, J. J. M.; Strohmayer, T. E.

2017-01-01

Thermonuclear X-ray bursts from accreting neutron stars power brief but strong irradiation of their surroundings, providing a unique way to study accretion physics. We analyze MAXI/Gas Slit Camera and Swift/XRT spectra of a day-long flash observed from IGR J17062-6143 in 2015. It is a rare case of recurring bursts at a low accretion luminosity of 0.15% Eddington. Spectra from MAXI, Chandra, and NuSTAR observations taken between the 2015 burst and the previous one in 2012 are used to determine the accretion column. We find it to be consistent with the burst ignition column of 5x10(exp 10) g cm (exp -2), which indicates that it is likely powered by burning in a deep helium layer. The burst flux is observed for over a day, and decays as a straight power law: F gamma t (exp -1.15). The burst and persistent spectra are well described by thermal emission from the neutron star, Comptonization of this emission in a hot optically thin medium surrounding the star, and reflection off the photoionized accretion disk. At the burst peak, the Comptonized component disappears, when the burst may dissipate the Comptonizing gas, and it returns in the burst tail. The reflection signal suggests that the inner disk is truncated at approximately 102 gravitational radii before the burst, but may move closer to the star during the burst. At the end of the burst, the flux drops below the burst cooling trend for 2 days, before returning to the pre-burst level.

Fusion Ignition Rocket Engine with Ballistic Ablative Lithium Liner

NASA Technical Reports Server (NTRS)

Martin, Adam; Eskridge, Richard; Fimognari, Peter J., III.

2005-01-01

Thermo-nuclear fusion may be the key to a high Isp, high specific power (low alpha) propulsion system. In a fusion system energy is liberated within, and imparted directly to, the propellant. In principle, this can overcome the performance limitations inherent in systems that require thermal power transfer across a material boundary, and/or multiple power conversion stages (NTR, NEP). A thermo-nuclear propulsion system, which attempts to overcome some of the problems inherent in the ORION concept, is described. A passive tapered liner is launched behind a vehicle, through a hole in a pusher-plate, that is connected to the vehicle by a shock-absorbing mechanism. A dense FRC plasmoid is then accelerated to high velocity (in excess of 1,000 km/s) and shot through the hole into the liner, when it has reached a given point down-range. The kinetic energy of the FRC is converted into thermal and magnetic-field energy, igniting a fusion bum in the magnetically confined plasma. The fusion reaction serves as an ignition source for the liner, which is made out of detonable materials. The energy liberated in this process is converted to thrust by the pusher-plate, as in the classic ORION concept. However with this concept, the vehicle does not carry a magazine of pre-fabricated pulse-units. A magnetic nozzle may also be used, in place of the pusher-plate. Estimates of the conditions needed to achieve a sufficient gain will be presented, along with a description of the driver characteristics. The incorporation of this concept into the propulsion system of a spacecraft will also be discussed.

Medical status of Marshallese accidentally exposed to 1954 Bravo fallout radiation: January 1988 through December 1991

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howard, J.E.; Heotis, P.M.; Scott, W.A.

1995-07-01

The purpose of this report is to disseminate information concerning the medical status of 253 Marshallese exposed to fallout radiation in 1954. This report discusses the medical care provided and the medical findings for the years 1988-1991. Details of the BRAVO thermonuclear accident that caused the exposure have been published, and a 1955 article in the Journal of the American Medical Association describing the acute medical effects in the exposed population remains a definitive and relevant description of events. Participation in the Marshall Islands Medical Program by the exposed Marshallese is voluntary. In the spring and fall of each year,more » medical surveillance is provided to exposed and unexposed cohorts. Examinations performed include: a cancer-related examination as defined by the American Society, an annual thyroid examination and thyroid function testing, serum prolactin testing looking for pituitary tumors, annual blood counts to include platelets, and evaluation for paraneoplastic evidence of neoplasms. This report details the medical program, medical findings, and thyroid surgery findings. Deaths (4 exposed and 10 nonexposed) that occurred during the reporting period are discussed. There is a mild but relatively consistent depression of neutrophil, lymphocyte, and platelet concentrations in the blood of the exposed population. This depression appears to be of no clinical significance. Thyroid hypofunction, either clinical or biochemical, has been documented as a consequence of radiation exposure in 14 exposed individuals. Previously, one other exposed person was diagnosed with basal cell carcinoma. During this reporting period, a thyroid nodule was identified in an individual who was in utero during the exposure. Upon pathologic review, the nodule was diagnosed as occult papillary carcinoma.« less

Staged Z-pinch Experiments at the 1MA Zebra pulsed-power generator: Neutron measurements

NASA Astrophysics Data System (ADS)

Ruskov, Emil; Darling, T.; Glebov, V.; Wessel, F. J.; Anderson, A.; Beg, F.; Conti, F.; Covington, A.; Dutra, E.; Narkis, J.; Rahman, H.; Ross, M.; Valenzuela, J.

2017-10-01

We report on neutron measurements from the latest Staged Z-pinch experiments at the 1MA Zebra pulsed-power generator. In these experiments a hollow shell of argon or krypton gas liner, injected between the 1 cm anode-cathode gap, compresses a deuterium plasma target of varying density. Axial magnetic field Bz <= 2 kGs, applied throughout the pinch region, stabilizes the Rayleigh-Taylor instability. The standard silver activation diagnostics and 4 plastic scintillator neutron Time of Flight (nTOF) detectors are augmented with a large area ( 1400 cm2) liquid scintillator detector to which fast gatedPhotek photomultipliers are attached. Sample data from these neutron diagnostics systems is presented. Consistently high neutron yields YDD >109 are measured, with highest yield of 2.6 ×109 . A pair of horizontally and vertically placed plastic scintillator nTOFs suggest isotropic i.e. thermonuclear origin of the neutrons produced. nTOF data from the liquid scintillator detector was cross-calibrated with the silver activation detector, and can be used for accurate calculation of the neutron yield. Funded by the Advanced Research Projects Agency - Energy, under Grant Number DE-AR0000569.

S-factor for radiative capture reactions for light nuclei at astrophysical energies

NASA Astrophysics Data System (ADS)

Ghasemi, Reza; Sadeghi, Hossein

2018-06-01

The astrophysical S-factors of thermonuclear reactions, including radiative capture reactions and their analysis in the frame of different theoretical models, are the main source of nuclear processes. We have done research on the radiative capture reactions importance in the framework of a potential model. Investigation of the reactions in the astrophysical energies is of great interest in the aspect of astrophysics and nuclear physics for developing correct models of burning and evolution of stars. The experimental measurements are very difficult and impossible because of these reactions occurrence at low-energies. In this paper we do a calculation on radiative capture astrophysical S-factors for nuclei in the mass region A < 17. We calculate the astrophysical factor for the dipole electronic transition E1 and magnetic dipole transition M1 and electric quadrupole transition E2 by using the M3Y potential for non-resonances and resonances captures. Then we have got the parameter of a central part and spin-orbit part of M3Y potential and spectroscopic factor for reaction channels. For the astrophysical S-factor of this article the good agreement is achieved In comparison with experimental data and other theoretical methods.

Control of Warm Compression Stations Using Model Predictive Control: Simulation and Experimental Results

NASA Astrophysics Data System (ADS)

Bonne, F.; Alamir, M.; Bonnay, P.

2017-02-01

This paper deals with multivariable constrained model predictive control for Warm Compression Stations (WCS). WCSs are subject to numerous constraints (limits on pressures, actuators) that need to be satisfied using appropriate algorithms. The strategy is to replace all the PID loops controlling the WCS with an optimally designed model-based multivariable loop. This new strategy leads to high stability and fast disturbance rejection such as those induced by a turbine or a compressor stop, a key-aspect in the case of large scale cryogenic refrigeration. The proposed control scheme can be used to achieve precise control of pressures in normal operation or to avoid reaching stopping criteria (such as excessive pressures) under high disturbances (such as a pulsed heat load expected to take place in future fusion reactors, expected in the cryogenic cooling systems of the International Thermonuclear Experimental Reactor ITER or the Japan Torus-60 Super Advanced fusion experiment JT-60SA). The paper details the simulator used to validate this new control scheme and the associated simulation results on the SBTs WCS. This work is partially supported through the French National Research Agency (ANR), task agreement ANR-13-SEED-0005.

Exploring the universe through Discovery Science on NIF

NASA Astrophysics Data System (ADS)

Remington, Bruce

2017-10-01

New regimes of science are being experimentally studied at high energy density facilities around the world, spanning drive energies from microjoules to megajoules, and time scales from femtoseconds to microseconds. The ability to shock and ramp compress samples to very high pressures and densities allows new states of matter relevant to planetary and stellar interiors to be studied. Shock driven hydrodynamic instabilities evolving into turbulent flows relevant to the dynamics of exploding stars (such as supernovae), accreting compact objects (such as white dwarfs, neutron stars, and black holes), and planetary formation dynamics (relevant to the exoplanets) are being probed. The dynamics of magnetized plasmas relevant to astrophysics, both in collisional and collisionless systems, are starting to be studied. High temperature, high velocity interacting flows are being probed for evidence of astrophysical collisionless shock formation, the turbulent magnetic dynamo effect, magnetic reconnection, and particle acceleration. And new results from thermonuclear reactions in hot dense plasmas relevant to stellar and big bang nucleosynthesis are starting to emerge. A selection of examples of frontier research through NIF Discovery Science in the coming decade will be presented. This work was performed under the auspices of U.S. DOE by LLNL under Contract DE-AC52-07NA27344.

The big contradiction between the perturbation theory and the chaotic state. A detailed mathematical analysis indicates when the plasma is stable or unstable

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xaplanteris, C. L., E-mail: cxaplanteris@yahoo.com; Xaplanteris, S. C.

2016-05-15

In the present manuscript enough observations and interpretations of three issues of Plasma Physics are presented. The first issue is linked to the common experimental confirmation of plasma waves which appear to be repeated in a standard way while there are also cases where plasma waves change to an unstable state or even to chaotic state. The second issue is associated with a mathematical analysis of the movement of a charged particle using the perturbation theory; which could be used as a guide for new researchers on similar issues. Finally, the suitability and applicability of the perturbation theory or themore » chaotic theory is presented. Although this study could be conducted on many plasma phenomena (e.g. plasma diffusion) or plasma quantities (e.g. plasma conductivity), here it was decided this study to be conducted on plasma waves and particularly on drift waves. This was because of the significance of waves on the plasmatic state and especially their negative impact on the thermonuclear fusion, but also due to the long-time experience of the plasma laboratory of Demokritos on drift waves.« less

Simultaneous measurement of the HT and DT fusion burn histories in inertial fusion implosions

DOE PAGES

Zylstra, Alex B.; Herrmann, Hans W.; Kim, Yong Ho; ...

2017-05-23

Measuring the thermonuclear burn history is an important way to diagnose inertial fusion implosions. Here, using the gas Cherenkov detectors at the OMEGA laser facility, we measure the HT fusion burn in a H 2+T 2 gas-fueled implosion for the first time. Then, using multiple detectors with varied Cherenkov thresholds, we demonstrate a technique for simultaneously measuring both the HT and DT burn histories from an implosion where the total reaction yields are comparable. This new technique will be used to study material mixing and kinetic phenomena in implosions.

Space and man. [planetary exploration and energy sources

NASA Technical Reports Server (NTRS)

Kolman, E.

1974-01-01

The effects of man's entry into space on changes in economics and technology, politics and law, science, philosophy, and art are considered. A single world economy, extracting from the natural resources of the moon and other cosmic bodies raw materials and energy, will avoid terrestrial limitations and improve society by eliminating the inequalities of economic and social status. However, a spacecraft for interplanetary travel require thermonuclear engines that achieve an escape velocity of 0.1 times the speed of light in order to allow an astronaut stellar expedition corresponding to the active life of a single generation.

HEDP and new directions for fusion energy

NASA Astrophysics Data System (ADS)

Kirkpatrick, Ronald C.

2010-06-01

Magnetic-confinement fusion energy and inertia-confinement fusion energy (IFE) represent two extreme approaches to the quest for the application of thermonuclear fusion to electrical energy generation. Blind pursuit of these extreme approaches has long delayed the achievement of their common goal. We point out the possibility of an intermediate approach that promises cheaper, and consequently more rapid development of fusion energy. For example, magneto-inertial fusion appears to be possible over a broad range of parameter space. It is further argued that imposition of artificial constraints impedes the discovery of physics solutions for the fusion energy problem.

Review of fusion synfuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fillo, J.A.

1980-01-01

Thermonuclear fusion offers an inexhaustible source of energy for the production of hydrogen from water. Depending on design, electric generation efficiencies of approx. 40 to 60% and hydrogen production efficiencies by high-temperature electrolysis of approx. 50 to 65% are projected for fusion reactors using high-temperatures blankets. Fusion/coal symbiotic systems appear economically promising for the first generation of commercial fusion synfuels plants. Coal production requirements and the environmental effects of large-scale coal usage would be greatly reduced by a fusion/coal system. In the long term, there could be a gradual transition to an inexhaustible energy system based solely on fusion.

Simultaneous measurement of the HT and DT fusion burn histories in inertial fusion implosions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zylstra, Alex B.; Herrmann, Hans W.; Kim, Yong Ho

Measuring the thermonuclear burn history is an important way to diagnose inertial fusion implosions. Here, using the gas Cherenkov detectors at the OMEGA laser facility, we measure the HT fusion burn in a H 2+T 2 gas-fueled implosion for the first time. Then, using multiple detectors with varied Cherenkov thresholds, we demonstrate a technique for simultaneously measuring both the HT and DT burn histories from an implosion where the total reaction yields are comparable. This new technique will be used to study material mixing and kinetic phenomena in implosions.

Nuclear clustering and the electron screening puzzle

NASA Astrophysics Data System (ADS)

Bertulani, C. A.; Spitaleri, C.

2018-01-01

Electron screening changes appreciably the magnitude of astrophysical nuclear reactions within stars. This effect is also observed in laboratory experiments on Earth, where atomic electrons are present in the nuclear targets. Theoretical models were developed over the past 30 years and experimental measurements have been carried out to study electron screening in thermonuclear reactions. None of the theoretical models were able to explain the high values of the experimentally determined screening potentials. We explore the possibility that the "electron screening puzzle" is due to nuclear clusterization and polarization e_ects in the fusion reactions. We will discuss the supporting arguments for this scenario.

The National Ignition Facility: The Path to a Carbon-Free Energy Future

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stolz, C J

2011-03-16

The National Ignition Facility (NIF), the world's largest and most energetic laser system, is now operational at Lawrence Livermore National Laboratory (LLNL). The NIF will enable exploration of scientific problems in national strategic security, basic science and fusion energy. One of the early NIF goals centers on achieving laboratory-scale thermonuclear ignition and energy gain, demonstrating the feasibility of laser fusion as a viable source of clean, carbon-free energy. This talk will discuss the precision technology and engineering challenges of building the NIF and those we must overcome to make fusion energy a commercial reality.

IMPROVEMENTS IN RADIATION SHUTTERS

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1961-07-12

An apparatus for the protection of eyesight from the radiated energy released from a thermonuclear explosion is described. The apparatus consists of a shutter which is opaque to the radiation, an electrically ignitible detonator for blowing the shutter across the path of the radiation, and a phototransistor for igniting the detonator when the radiated energy exceeds a level which is injurious to the eyesight. There may be a second detonator for blowing the shutter away after the explosion has subsided. The second detonator is manually operated. Diagrams show the apparatus attached to a soldier's helmet and a turret. (N.W.R.)

Recent Results on SNRs and PWNe from the Fermi Large Area Telescope

NASA Technical Reports Server (NTRS)

Hays, Elizabeth

2010-01-01

a) Symbiotic Binary System: White dwarf + red giant system. b) Nova: White dwarf builds up mass envelope to the point of thermonuclear fusion. c) Dramatic increase in visual magnitude. d) Recurrent Nova? e) Hints but no strong confirmation of previous nova f) Pre-nova activity: 1) White dwarf shows ongoing variability at level of several in magnitude. 2) V407 Cyg companion is a Mira star showing variability at level of several in magnitude. g) Origin of the gamma rays? 1) Strong shock propagating into dense medium around giant star land stellar wind. 2) Pion decay or electron processes?

Diagnosing magnetized liner inertial fusion experiments on Z

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansen, Stephanie B.; Gomez, Matthew R.; Sefkow, Adam B.

The Magnetized Liner Inertial Fusion experiments performed at Sandia's Z facility have demonstrated significant thermonuclear fusion neutron yields (~10 12 DD neutrons) from multi-keV deuterium plasmasinertially confined by slow (~10 cm/μs), stable, cylindrical implosions. Moreover, effective magnetic confinement of charged fusion reactants and products is signaled by high secondary DT neutron yields above 10 10. Further analysis of extensive power, imaging, and spectroscopicx-ray measurements provides a detailed picture of ~3 keV temperatures, 0.3 g/cm 3 densities, gradients, and mix in the fuel and liner over the 1–2 ns stagnation duration.

Diagnosing magnetized liner inertial fusion experiments on Z

DOE PAGES

Hansen, Stephanie B.; Gomez, Matthew R.; Sefkow, Adam B.; ...

2015-05-14

The Magnetized Liner Inertial Fusion experiments performed at Sandia's Z facility have demonstrated significant thermonuclear fusion neutron yields (~10 12 DD neutrons) from multi-keV deuterium plasmasinertially confined by slow (~10 cm/μs), stable, cylindrical implosions. Moreover, effective magnetic confinement of charged fusion reactants and products is signaled by high secondary DT neutron yields above 10 10. Further analysis of extensive power, imaging, and spectroscopicx-ray measurements provides a detailed picture of ~3 keV temperatures, 0.3 g/cm 3 densities, gradients, and mix in the fuel and liner over the 1–2 ns stagnation duration.

The National Ignition Facility: the path to a carbon-free energy future.

PubMed

Stolz, Christopher J

2012-08-28

The National Ignition Facility (NIF), the world's largest and most energetic laser system, is now operational at Lawrence Livermore National Laboratory. The NIF will enable exploration of scientific problems in national strategic security, basic science and fusion energy. One of the early NIF goals centres on achieving laboratory-scale thermonuclear ignition and energy gain, demonstrating the feasibility of laser fusion as a viable source of clean, carbon-free energy. This talk will discuss the precision technology and engineering challenges of building the NIF and those we must overcome to make fusion energy a commercial reality.

Photometric and Spectroscopic Analysis of Classical Novae: An Examination of Their Observational Characteristics and Greater Astronomical Impact

NASA Astrophysics Data System (ADS)

Helton, Lorren Andrew

2010-12-01

Classical novae (CNe) are violent thermonuclear explosions arising on the surface of white dwarfs in binary systems and are contributors to the chemical evolution of the interstellar medium through the production and ejection of copious amounts of metal-rich material. Observations and modeling of CNe eruptions illuminate numerous fundamental processes of astrophysical interest, including non-equilibrium thermonuclear runaway, radiative processes in dynamic nebular environments, binary star interaction, as well as dust condensation and grain growth. Here I summarize key findings from selected Galactic CNe observed as part of a 5 year, panchromatic optical/infrared observing campaign using Spitzer, Gemini, and other ground based optical facilities. In particular, I present detailed analysis of nova V1065 Centauri, including photoionization analysis of the emission lines, which enabled the derivation of abundances in the ejecta, and radiative transport modeling of the dust emission features, which allowed determination of the composition and characteristics of the dust in this system. I present analysis of three novae, V1974 Cygni, V382 Velorum, and V1494 Aquilae, observed from 4.4--15.5 years after outburst, discuss the characteristics of the nebulae at these late times, and estimate the abundances in their ejecta. In the case of V1494 Aql, I also report the first detection of neon. Finally, I present observations of three novae, DZ Crucis, V2361 Cygni, and V2362 Cygni, that exhibited unidentified infrared (UIR) features in their mid-infrared spectra, which exhibited unusual characteristics. I relate these features to other dusty novae in which features with similar characteristics were observed, and discuss possible sources for the UIR carriers. Analysis of the data obtained in the CNe monitoring campaign presented here highlights the need for synoptic observations obtained with broad wavelength coverage. Observations of V1065 Cen, which exhibited spectra rich in metals (e.g O, Ne, Mg, S, Ar, and Fe) produced during the thermonuclear runaway and through dredge up from the surface layers of the underlying WD, yielded robust estimates of WD composition, ejecta mass, and absolute abundances in the ejecta. Dusty novae such as V1065 Cen, V2362 Cyg, and V2361 Cyg, produced a variety of grain types as revealed by emission features characteristic of silicates, hydrogenated amorphous carbon dust, and PAH-like molecules, often in the same system. This data set is exceptional in that observations of many targets commenced immediately after eruption and followed the development for hundreds of days post-outburst providing unique insight into the evolution of conditions within the ejecta including the complete cycle of growth, processing, and dissipation of dust grains.

The national ignition facility high-energy ultraviolet laser system

NASA Astrophysics Data System (ADS)

Moses, Edward I.

2004-09-01

The National Ignition Facility (NIF), currently under construction at the Lawrence Livermore National Laboratory, is a stadium-sized facility containing a 192-beam, 1.8 MJ, 500 TW, ultraviolet laser system together with a 10-m diameter target chamber with room for nearly 100 experimental diagnostics. When completed, NIF will be the world's largest and most energetic laser experimental system, providing an international center to study inertial confinement fusion and the physics of matter at extreme energy densities and pressures. NIF's 192 energetic laser beams will compress fusion targets to conditions required for thermonuclear burn, liberating more energy than required to initiate the fusion reactions. Other NIF experiments will allow the study of physical processes at temperatures approaching 10 8 K and 10 11 Bar, conditions that exist naturally only in the interior of stars, planets and in nuclear weapons. NIF is now entering the first phases of its laser commissioning program. The first four beams of the NIF laser system have generated 106 kJ of infrared light and over 10 kJ at the third harmonic (351 nm). NIF's target experimental systems are also being installed in preparation for experiments to begin in late 2003. This paper provides a detailed look the NIF laser systems, the significant laser and optical systems breakthroughs that were developed, the results of recent laser commissioning shots, and plans for commissioning diagnostics for experiments on NIF.

OPTICAL THERMONUCLEAR TRANSIENTS FROM TIDAL COMPRESSION OF WHITE DWARFS AS TRACERS OF THE LOW END OF THE MASSIVE BLACK HOLE MASS FUNCTION

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacLeod, Morgan; Ramirez-Ruiz, Enrico; Guillochon, James

In this paper, we model the observable signatures of tidal disruptions of white dwarf (WD) stars using massive black holes (MBHs) of moderate mass, ≈10{sup 3}–10{sup 5} M{sub ⊙}. When the WD passes deep enough within the MBH’s tidal field, these signatures include thermonuclear transients from burning during maximum compression. We combine a hydrodynamic simulation that includes nuclear burning of the disruption of a 0.6 M{sub ⊙} C/O WD with a Monte Carlo radiative transfer calculation to synthesize the properties of a representative transient. The transient’s emission emerges in the optical, with light curves and spectra reminiscent of Type I supernovae. Themore » properties are strongly viewing angle dependent, and key spectral signatures are ≈10,000 km s{sup −1} doppler shifts, due to the orbital motion of the unbound ejecta. Disruptions of He WDs likely produce large quantities of intermediate-mass elements, offering a possible production mechanism for Ca-rich transients. Accompanying multi-wavelength transients are fueled by accretion and arise from the nascent accretion disk and relativistic jet. If MBHs of moderate mass exist with number densities similar to those of supermassive BHs, both high-energy wide-field monitors and upcoming optical surveys should detect tens to hundreds of WD tidal disruptions per year. The current best strategy for their detection may therefore be deep optical follow-up of high-energy transients of unusually long duration. The detection rate or the nondetection of these transients by current and upcoming surveys can thus be used to place meaningful constraints on the extrapolation of the MBH mass function to moderate masses.« less

CXO J004318.8+412016, a steady supersoft X-ray source in M 31

NASA Astrophysics Data System (ADS)

Orio, Marina; Luna, G. J. M.; Kotulla, R.; Gallager, J. S.; Zampieri, L.; Mikolajewska, J.; Harbeck, D.; Bianchini, A.; Chiosi, E.; Della Valle, M.; de Martino, D.; Kaur, A.; Mapelli, M.; Munari, U.; Odendaal, A.; Trinchieri, G.; Wade, J.; Zemko, P.

2017-09-01

We obtained an optical spectrum of a star we identify as the optical counterpart of the M31 Chandra source CXO J004318.8+412016, because of prominent emission lines of the Balmer series, of neutral helium, and a He II line at 4686 Å. The continuum energy distribution and the spectral characteristics demonstrate the presence of a red giant of K or earlier spectral type, so we concluded that the binary is likely to be a symbiotic system. CXO J004318.8+412016 has been observed in X-rays as a luminous supersoft source (SSS) since 1979, with effective temperature exceeding 40 eV and variable X-ray luminosity, oscillating between a few times 1035 erg s-1 and a few times 1037 erg s-1 in the space of a few weeks. The optical, infrared and ultraviolet colours of the optical object are consistent with an an accretion disc around a compact object companion, which may be either a white dwarf or a black hole, depending on the system parameters. If the origin of the luminous supersoft X-rays is the atmosphere of a white dwarf that is burning hydrogen in shell, it is as hot and luminous as post-thermonuclear flash novae, yet no major optical outburst has ever been observed, suggesting that the white dwarf is very massive (m ≥ 1.2 M⊙) and it is accreting and burning at the high rate \\dot{m} > 10^{-8} M⊙ yr-1 expected for Type Ia supernovae progenitors. In this case, the X-ray variability may be due to a very short recurrence time of only mildly degenerate thermonuclear flashes.

Neutrino Signal of Collapse-induced Thermonuclear Supernovae: The Case for Prompt Black Hole Formation in SN 1987A

NASA Astrophysics Data System (ADS)

Blum, Kfir; Kushnir, Doron

2016-09-01

Collapse-induced thermonuclear explosion (CITE) may explain core-collapse supernovae (CCSNe). We analyze the neutrino signal in CITE and compare it to the neutrino burst of SN 1987A. For strong (≳ {10}51 erg) CCSNe, such as SN 1987A, CITE predicts a proto-neutron star (PNS) accretion phase lasting up to a few seconds that is cut off by black hole (BH) formation. The neutrino luminosity can later be revived by accretion disk emission after a dead time of a few to a few tens of seconds. In contrast, the neutrino mechanism for CCSNe predicts a short (≲s) PNS accretion phase, followed by slowly declining PNS cooling luminosity. We repeat statistical analyses used in the literature to interpret the neutrino mechanism, and apply them to CITE. The first 1-2 s of the neutrino burst are equally compatible with CITE and with the neutrino mechanism. However, the data points toward a luminosity drop at t = 2-3 s, which is in some tension with the neutrino mechanism but can be naturally attributed to BH formation in CITE. The occurrence of neutrino signal events at 5 s suggests that, within CITE, the accretion disk formed by that time. We perform two-dimensional numerical simulations showing that CITE may be able to accommodate this disk formation time while reproducing the ejected 56Ni mass and ejecta kinetic energy within factors of 2-3 of observations. We estimate the accretion disk neutrino luminosity, finding it to be on the low side but compatible with the data to a factor of 10. Given comparable uncertainties in the disk luminosity simulation, we conclude that direct BH formation may have occurred in SN 1987A.

X-Ray Reflection and an Exceptionally Long Thermonuclear Helium Burst from IGR J17062-6143

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keek, L.; Strohmayer, T. E.; Iwakiri, W.

Thermonuclear X-ray bursts from accreting neutron stars power brief but strong irradiation of their surroundings, providing a unique way to study accretion physics. We analyze MAXI /Gas Slit Camera and Swift /XRT spectra of a day-long flash observed from IGR J17062-6143 in 2015. It is a rare case of recurring bursts at a low accretion luminosity of 0.15% Eddington. Spectra from MAXI , Chandra , and NuSTAR observations taken between the 2015 burst and the previous one in 2012 are used to determine the accretion column. We find it to be consistent with the burst ignition column of 5×10{sup 10}more » g cm{sup −2}, which indicates that it is likely powered by burning in a deep helium layer. The burst flux is observed for over a day, and decays as a straight power law: F ∝ t {sup −1.15}. The burst and persistent spectra are well described by thermal emission from the neutron star, Comptonization of this emission in a hot optically thin medium surrounding the star, and reflection off the photoionized accretion disk. At the burst peak, the Comptonized component disappears, when the burst may dissipate the Comptonizing gas, and it returns in the burst tail. The reflection signal suggests that the inner disk is truncated at ∼10{sup 2} gravitational radii before the burst, but may move closer to the star during the burst. At the end of the burst, the flux drops below the burst cooling trend for 2 days, before returning to the pre-burst level.« less

Discovery of the Neutron Star Spin Frequency in EXO 0748-676

NASA Technical Reports Server (NTRS)

Villarreal, Adam R.; Strohmayer, Tod E.

2004-01-01

We report the results of a search for burst oscillations during thermonuclear X-ray bursts from the low mass X-ray binary (LMXB) EXO 0748-676. With the proportional counter array (PCA) onboard the Rossi X-ray Timing Explorer (RXTE) we have detected a 45 Hz oscillation in the average power spectrum of 38 thermonuclear X-ray bursts from this source. We computed power spectra with 1 Hz frequency resolution for both the rising and decaying portions of 38 X-ray bursts from the public RXTE archive. We averaged the 1 Hz power spectra and detected a significant signal at 45 Hz in the decaying phases of the bursts. The signal is detected at a significance level of 4 x 10 (exp -8) similar signal was detected in the rising intervals. The oscillation peak is unresolved at 1 Hz frequency resolution, indicating an oscillation quality factor, Q = nu (sub 0)/Delta nu (sub fwhm) greater than 45, and the average signal amplitude is approximately equal to 3% (rms) The detection of 45 Hz burst oscillations from EXO 0748-676 provides compelling evidence that this is the neutron star spin frequency in this system. We use the inferred spin frequency to model the widths of absorption lines from the neutron star surface and show that the widths of the absorption lines from EXO 0748-676 recently reported by Cottam et al. are consistent with a 45 Hz spin frequency as long as the neutron star radius is in the range from about 9.5 - 15 km. With a known spin frequency, precise modelling of the line profiles from EXO 0748-676 holds great promise for constraining the dense matter equation of state.

Three-dimensional simulations of turbulent convective mixing in ONe and CO classical nova explosions

DOE PAGES

Casanova, Jordi; José, Jordi; García-Berro, Enrique; ...

2016-10-25

Classical novae are thermonuclear explosions that take place in the envelopes of accreting white dwarfs in binary systems. The material piles up under degenerate conditions, driving a thermonuclear runaway. The energy released by the suite of nuclear processes operating at the envelope heats the material up to peak temperatures of ~(1-4) × 10 8 K. During these events, about 10 -3-10 -7 M ⊙, enriched in CNO and, sometimes, other intermediate-mass elements (e.g., Ne, Na, Mg, Al) are ejected into the interstellar medium. To account for the gross observational properties of classical novae (in particular, the high concentrations of metalsmore » spectroscopically inferred in the ejecta), models require mixing between the (solar-like) material transferred from the secondary and the outermost layers (CO- or ONe-rich) of the underlying white dwarf. Recent multidimensional simulations have demonstrated that Kelvin-Helmholtz instabilities can naturally produce self-enrichment of the accreted envelope with material from the underlying white dwarf at levels that agree with observations. However, the feasibility of this mechanism has been explored in the framework of CO white dwarfs, while mixing with different substrates still needs to be properly addressed. We performed three-dimensional simulations of mixing at the core-envelope interface during nova outbursts with the multidimensional code FLASH, for two types of substrates: CO- and ONe-rich. We also show that the presence of an ONe-rich substrate, as in “neon novae”, yields higher metallicity enhancements in the ejecta than CO-rich substrates (i.e., non-neon novae). Finally, a number of requirements and constraints for such 3D simulations (e.g., minimum resolution, size of the computational domain) are also outlined.« less

Three-dimensional simulations of the interaction between the nova ejecta, accretion disk, and companion star

NASA Astrophysics Data System (ADS)

Figueira, Joana; José, Jordi; García-Berro, Enrique; Campbell, Simon W.; García-Senz, Domingo; Mohamed, Shazrene

2018-05-01

Context. Classical novae are thermonuclear explosions hosted by accreting white dwarfs in stellar binary systems. Material piles up on top of the white dwarf star under mildly degenerate conditions, driving a thermonuclear runaway. The energy released by the suite of nuclear processes operating at the envelope, mostly proton-capture reactions and β+-decays, heats the material up to peak temperatures ranging from 100 to 400 MK. In these events, about 10-3-10-7 M⊙, enriched in CNO and, sometimes, other intermediate-mass elements (e.g., Ne, Na, Mg, and Al) are ejected into the interstellar medium. Aims: To date, most of the efforts undertaken in the modeling of classical nova outbursts have focused on the early stages of the explosion and ejection, ignoring the interaction of the ejecta, first with the accretion disk orbiting the white dwarf and ultimately with the secondary star. Methods: A suite of 3D, smoothed-particle hydrodynamics (SPH) simulations of the interaction between the nova ejecta, accretion disk, and stellar companion were performed to fill this gap; these simulations were aimed at testing the influence of the model parameters—that is, the mass and velocity of the ejecta, mass and the geometry of the accretion disk—on the dynamical and chemical properties of the system. Results: We discuss the conditions that lead to the disruption of the accretion disk and to mass loss from the binary system. In addition, we discuss the likelihood of chemical contamination of the stellar secondary induced by the impact with the nova ejecta and its potential effect on the next nova cycle. Movies showing the full evolution of several models are available online at http://https://www.aanda.org and at http://www.fen.upc.edu/users/jjose/Downloads.html

Investigation of the thermonuclear 18Ne(α,p)21Na reaction rate via resonant elastic scattering of 21Na + p

NASA Astrophysics Data System (ADS)

Zhang, L. Y.; He, J. J.; Parikh, A.; Xu, S. W.; Yamaguchi, H.; Kahl, D.; Kubono, S.; Mohr, P.; Hu, J.; Ma, P.; Chen, S. Z.; Wakabayashi, Y.; Wang, H. W.; Tian, W. D.; Chen, R. F.; Guo, B.; Hashimoto, T.; Togano, Y.; Hayakawa, S.; Teranishi, T.; Iwasa, N.; Yamada, T.; Komatsubara, T.; Zhang, Y. H.; Zhou, X. H.

2014-01-01

The 18Ne(α,p)21Na reaction is thought to be one of the key breakout reactions from the hot CNO cycles to the rp process in type I x-ray bursts. In this work, the resonant properties of the compound nucleus 22Mg have been investigated by measuring the resonant elastic scattering of 21Na + p. An 89-MeV 21Na radioactive beam delivered from the CNS Radioactive Ion Beam Separator bombarded an 8.8 mg/cm2 thick polyethylene (CH2)n target. The 21Na beam intensity was about 2×105 pps, with a purity of about 70% on target. The recoiled protons were measured at the center-of-mass scattering angles of θc.m.≈175.2∘, 152.2∘, and 150.5∘ by three sets of ΔE-E telescopes, respectively. The excitation function was obtained with the thick-target method over energies Ex(22Mg)=5.5-9.2 MeV. In total, 23 states above the proton-threshold in 22Mg were observed, and their resonant parameters were determined via an R-matrix analysis of the excitation functions. We have made several new Jπ assignments and confirmed some tentative assignments made in previous work. The thermonuclear 18Ne(α,p)21Na rate has been recalculated based on our recommended spin-parity assignments. The astrophysical impact of our new rate has been investigated through one-zone postprocessing x-ray burst calculations. We find that the 18Ne(α,p)21Na rate significantly affects the peak nuclear energy generation rate, reaction fluxes, and onset temperature of this breakout reaction in these astrophysical phenomena.

First operation with the JET International Thermonuclear Experimental Reactor-like walla)

NASA Astrophysics Data System (ADS)

Neu, R.; Arnoux, G.; Beurskens, M.; Bobkov, V.; Brezinsek, S.; Bucalossi, J.; Calabro, G.; Challis, C.; Coenen, J. W.; de la Luna, E.; de Vries, P. C.; Dux, R.; Frassinetti, L.; Giroud, C.; Groth, M.; Hobirk, J.; Joffrin, E.; Lang, P.; Lehnen, M.; Lerche, E.; Loarer, T.; Lomas, P.; Maddison, G.; Maggi, C.; Matthews, G.; Marsen, S.; Mayoral, M.-L.; Meigs, A.; Mertens, Ph.; Nunes, I.; Philipps, V.; Pütterich, T.; Rimini, F.; Sertoli, M.; Sieglin, B.; Sips, A. C. C.; van Eester, D.; van Rooij, G.; JET-EFDA Contributors

2013-05-01

To consolidate International Thermonuclear Experimental Reactor (ITER) design choices and prepare for its operation, Joint European Torus (JET) has implemented ITER's plasma facing materials, namely, Be for the main wall and W in the divertor. In addition, protection systems, diagnostics, and the vertical stability control were upgraded and the heating capability of the neutral beams was increased to over 30 MW. First results confirm the expected benefits and the limitations of all metal plasma facing components (PFCs) but also yield understanding of operational issues directly relating to ITER. H-retention is lower by at least a factor of 10 in all operational scenarios compared to that with C PFCs. The lower C content (≈ factor 10) has led to much lower radiation during the plasma burn-through phase eliminating breakdown failures. Similarly, the intrinsic radiation observed during disruptions is very low, leading to high power loads and to a slow current quench. Massive gas injection using a D2/Ar mixture restores levels of radiation and vessel forces similar to those of mitigated disruptions with the C wall. Dedicated L-H transition experiments indicate a 30% power threshold reduction, a distinct minimum density, and a pronounced shape dependence. The L-mode density limit was found to be up to 30% higher than for C allowing stable detached divertor operation over a larger density range. Stable H-modes as well as the hybrid scenario could be re-established only when using gas puff levels of a few 1021 es-1. On average, the confinement is lower with the new PFCs, but nevertheless, H factors up to 1 (H-Mode) and 1.3 (at βN≈3, hybrids) have been achieved with W concentrations well below the maximum acceptable level.

The Interaction of High-Speed Turbulence with Flames

NASA Astrophysics Data System (ADS)

Poludnenko, Alexei Y.; Oran, E. S.

2010-01-01

Interaction of flames with turbulence occurs in systems ranging from chemical flames on Earth to thermonuclear burning fronts, which are presently believed to be the key component of the explosion mechanism powering the type Ia supernovae. A number of important questions remains concerning the dynamics of turbulent flames in the presence of high-speed turbulence, the flame structure and stability, as well as the ability of the turbulent cascade to penetrate and disrupt the flame creating the distributed mode of burning. We present results of a systematic study of the dynamics and properties of turbulent flames formed under the action of high-speed turbulence using a simplified one-step kinetics similar to the one used to describe hydrogen combustion. This approach makes large-scale highly resolved simulations computationally feasible and it allows one to focus on the process of the turbulence-flame interaction in a simplified controlled setting. Numerical simulations were performed using the massively parallel reactive-flow code Athena-RFX. We discuss global properties of the turbulent flame in this regime (flame width, speed, etc.) and the internal structure of the flame brush. A method is presented for directly reconstructing the internal flame structure and it is shown that correct characterization of the flame regime can be very sensitive to the proper choice of the diagnostic method. We discuss the ability of the turbulent cascade to penetrate the internal flame structure. Finally, we also consider the processes that determine the turbulent burning velocity and identify two distinct regimes of flame evolution. This work was supported in part by the National Research Council, Naval Research Laboratory, and the Office of Naval Research, and by the National Science Foundation through the TeraGrid resources.

Relativistic astrophysics. [design analysis and performance tests of Cerenkov counters for detection of iron isotopes

NASA Technical Reports Server (NTRS)

Price, P. B.

1976-01-01

The design, experimental testing, and calibration (error analysis) of a high resolution Cerenkov-scintillation detector is presented. The detector is capable of detecting iron isotopes and heavy ions of cosmic rays, and of performing direct measurements of individual neighboring isotopes at charge resolution 26. It utilizes Lexan (trademark) sheets, and has been used in flight packages of balloons and on the Skylab. The detector will be able to provide more information on violet astrophysical processes, such as thermonuclear reactions on neutron stars. Ground support and display equipment which are to be used in conjunction with the detector are also discussed.

Stellar nucleosynthesis and chemical evolution of the solar neighborhood

NASA Technical Reports Server (NTRS)

Clayton, Donald D.

1988-01-01

Current theoretical models of nucleosynthesis (N) in stars are reviewed, with an emphasis on their implications for Galactic chemical evolution. Topics addressed include the Galactic population II red giants and early N; N in the big bang; star formation, stellar evolution, and the ejection of thermonuclearly evolved debris; the chemical evolution of an idealized disk galaxy; analytical solutions for a closed-box model with continuous infall; and nuclear burning processes and yields. Consideration is given to shell N in massive stars, N related to degenerate cores, and the types of observational data used to constrain N models. Extensive diagrams, graphs, and tables of numerical data are provided.

Report from solar physics

NASA Technical Reports Server (NTRS)

Walker, A. B. C.; Acton, L.; Brueckner, G.; Chupp, E. L.; Hudson, H. S.; Roberts, W.

1989-01-01

A discussion of the nature of solar physics is followed by a brief review of recent advances in the field. These advances include: the first direct experimental confirmation of the central role played by thermonuclear processes in stars; the discovery that the 5-minute oscillations of the Sun are a global seismic phenomenon that can be used as a probe of the structure and dynamical behavior of the solar interior; the discovery that the solar magnetic field is subdivided into individual flux tubes with field strength exceeding 1000 gauss. Also covered was a science strategy for pure solar physics. Brief discussions are given of solar-terrestrial physics, solar/stellar relationships, and suggested space missions.

Models for Type Ia Supernovae and Related Astrophysical Transients

NASA Astrophysics Data System (ADS)

Röpke, Friedrich K.; Sim, Stuart A.

2018-06-01

We give an overview of recent efforts to model Type Ia supernovae and related astrophysical transients resulting from thermonuclear explosions in white dwarfs. In particular we point out the challenges resulting from the multi-physics multi-scale nature of the problem and discuss possible numerical approaches to meet them in hydrodynamical explosion simulations and radiative transfer modeling. We give examples of how these methods are applied to several explosion scenarios that have been proposed to explain distinct subsets or, in some cases, the majority of the observed events. In case we comment on some of the successes and shortcoming of these scenarios and highlight important outstanding issues.

Theories of white dwarf oscillations

NASA Technical Reports Server (NTRS)

Vanhorn, H. M.

1980-01-01

The current status of theoretical understanding of the oscillations observed in the ZZ Ceti stars and cataclysmic variables is briefly reviewed. Nonradial g-mode oscillations appear to provide a satisfactory explanation for the low amplitude variables such as R548, with periods in the range of approximately 200 to 300 seconds, but for the longer period (800 to 1000 seconds) oscillators, the situation is still unclear. Rotation may play an important role in this problem, and the effects of both slow and fast rotation upon the mode structure are discussed. In the cataclysmic variables, both accretion and thermonuclear burning may act to excite oscillations of the white dwarf.

Fast Ignition Thermonuclear Fusion: Enhancement of the Pellet Gain by the Colossal-Magnetic-Field Shells

NASA Astrophysics Data System (ADS)

Stefan, V. Alexander

2013-10-01

The fast ignition fusion pellet gain can be enhanced by a laser generated B-field shell. The B-field shell, (similar to Earth's B-field, but with the alternating B-poles), follows the pellet compression in a frozen-in B-field regime. A properly designed laser-pellet coupling can lead to the generation of a B-field shell, (up to 100 MG), which inhibits electron thermal transport and confines the alpha-particles. In principle, a pellet gain of few-100s can be achieved in this manner. Supported in part by Nikola Tesla Labs, Stefan University, 1010 Pearl, La Jolla, CA 92038-1007.

Device and method for electron beam heating of a high density plasma

DOEpatents

Thode, L.E.

A device and method for relativistic electron beam heating of a high density plasma in a small localized region are described. A relativistic electron beam generator produces a high voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high density target plasma which typically comprises DT, DD, hydrogen boron or similar thermonuclear gas at a density of 10/sup 17/ to 10/sup 20/.

Scientific millenarianism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weinberg, A.M.

Today, for the first time, scientific concerns are seriously being addressed that span future times--hundreds, even thousands, or more years in the future. One is witnessing what the author calls scientific millenarianism. Are such concerns for the distant future exercises in futility, or are they real issues that, to the everlasting gratitude of future generations, this generation has identified, warned about and even suggested how to cope with in the distant future? Can the four potential catastrophes--bolide impact, CO{sub 2} warming, radioactive wastes and thermonuclear war--be avoided by technical fixes, institutional responses, religion, or by doing nothing? These are themore » questions addressed in this paper.« less

X-ray observations of the burst source MXB 1728 - 34

NASA Technical Reports Server (NTRS)

Basinska, E. M.; Lewin, W. H. G.; Sztajno, M.; Cominsky, L. R.; Marshall, F. J.

1984-01-01

Where sufficient information has been obtained, attention is given to the maximum burst flux, integrated burst flux, spectral hardness, rise time, etc., of 96 X-ray bursts observed from March 1976 to March 1979. The integrated burst flux and the burst frequency appear to be correlated; the longer the burst interval, the larger the integrated burst flux, as expected on the basis of simple thermonuclear flash models. The maximum burst flux and the integrated burst flux are strongly correlated; for low flux levels their dependence is approximately linear, while for increasing values of the integrated burst flux, the flux at burst maximum saturates and reaches a plateau.

Acceleration to high velocities and heating by impact using Nike KrF lasera)

NASA Astrophysics Data System (ADS)

Karasik, Max; Weaver, J. L.; Aglitskiy, Y.; Watari, T.; Arikawa, Y.; Sakaiya, T.; Oh, J.; Velikovich, A. L.; Zalesak, S. T.; Bates, J. W.; Obenschain, S. P.; Schmitt, A. J.; Murakami, M.; Azechi, H.

2010-05-01

The Nike krypton fluoride laser [S. P. Obenschain, S. E. Bodner, D. Colombant, et al., Phys. Plasmas 3, 2098 (1996)] is used to accelerate planar plastic foils to velocities that for the first time reach 1000 km/s. Collision of the highly accelerated deuterated polystyrene foil with a stationary target produces ˜Gbar shock pressures and results in heating of the foil to thermonuclear temperatures. The impact conditions are diagnosed using DD fusion neutron yield, with ˜106 neutrons produced during the collision. Time-of-flight neutron detectors are used to measure the ion temperature upon impact, which reaches 2-3 keV.

Diagnosing magnetized liner inertial fusion experiments on Z

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansen, S. B., E-mail: sbhanse@sandia.gov; Gomez, M. R.; Sefkow, A. B.

Magnetized Liner Inertial Fusion experiments performed at Sandia's Z facility have demonstrated significant thermonuclear fusion neutron yields (∼10{sup 12} DD neutrons) from multi-keV deuterium plasmas inertially confined by slow (∼10 cm/μs), stable, cylindrical implosions. Effective magnetic confinement of charged fusion reactants and products is signaled by high secondary DT neutron yields above 10{sup 10}. Analysis of extensive power, imaging, and spectroscopic x-ray measurements provides a detailed picture of ∼3 keV temperatures, 0.3 g/cm{sup 3} densities, gradients, and mix in the fuel and liner over the 1–2 ns stagnation duration.

An effect of nuclear electric quadrupole moments in thermonuclear fusion plasmas

NASA Technical Reports Server (NTRS)

De, B. R.; Srnka, L. J.

1978-01-01

Consideration of the nuclear electric quadrupole terms in the expression for the fusion Coulomb barrier suggests that this electrostatic barrier may be substantially modified from that calculated under the usual plasma assumption that the nuclei are electric monopoles. This effect is a result of the nonspherical potential shape and the spatial quantization of the nuclear spins of the fully stripped ions in the presence of a magnetic field. For monopole-quadrupole fuel cycles like p-B-11, the fusion cross-section may be substantially increased at low energies if the protons are injected at a small angle relative to the confining magnetic field.

Conceptual design of ACB-CP for ITER cryogenic system

NASA Astrophysics Data System (ADS)

Jiang, Yongcheng; Xiong, Lianyou; Peng, Nan; Tang, Jiancheng; Liu, Liqiang; Zhang, Liang

2012-06-01

ACB-CP (Auxiliary Cold Box for Cryopumps) is used to supply the cryopumps system with necessary cryogen in ITER (International Thermonuclear Experimental Reactor) cryogenic distribution system. The conceptual design of ACB-CP contains thermo-hydraulic analysis, 3D structure design and strength checking. Through the thermohydraulic analysis, the main specifications of process valves, pressure safety valves, pipes, heat exchangers can be decided. During the 3D structure design process, vacuum requirement, adiabatic requirement, assembly constraints and maintenance requirement have been considered to arrange the pipes, valves and other components. The strength checking has been performed to crosscheck if the 3D design meets the strength requirements for the ACB-CP.

Calibration procedures of the Tore-Supra infrared endoscopes

NASA Astrophysics Data System (ADS)

Desgranges, C.; Jouve, M.; Balorin, C.; Reichle, R.; Firdaouss, M.; Lipa, M.; Chantant, M.; Gardarein, J. L.; Saille, A.; Loarer, T.

2018-01-01

Five endoscopes equipped with infrared cameras working in the medium infrared range (3-5 μm) are installed on the controlled thermonuclear fusion research device Tore-Supra. These endoscopes aim at monitoring the plasma facing components surface temperature to prevent their overheating. Signals delivered by infrared cameras through endoscopes are analysed and used on the one hand through a real time feedback control loop acting on the heating systems of the plasma to decrease plasma facing components surface temperatures when necessary, on the other hand for physics studies such as determination of the incoming heat flux . To ensure these two roles a very accurate knowledge of the absolute surface temperatures is mandatory. Consequently the infrared endoscopes must be calibrated through a very careful procedure. This means determining their transmission coefficients which is a delicate operation. Methods to calibrate infrared endoscopes during the shutdown period of the Tore-Supra machine will be presented. As they do not allow determining the possible transmittances evolution during operation an in-situ method is presented. It permits the validation of the calibration performed in laboratory as well as the monitoring of their evolution during machine operation. This is possible by the use of the endoscope shutter and a dedicated plasma scenario developed to heat it. Possible improvements of this method are briefly evoked.

Peculiarities of heat transfer at the liquid metal flow in a vertical channel in a coplanar magnetic field

NASA Astrophysics Data System (ADS)

Razuvanov, N. G.; Poddubnyi, I. I.; Kostychev, P. V.

2017-11-01

The research of hydrodynamics and heat transfer at the liquid metal (LM) downward flow and upflow in a vertical duct of a rectangular cross section with a ratio of sides ˜1/3 in a coplanar magnetic field (MF) under conditions of bilateral symmetrical heating is performed. The problem simulates the LM flow in the heat exchange channels for cooling the liquid metal module of the blanket of the thermonuclear reactor (TNR) of the TOKAMAK type. The experiments were carried out on the basis of the mercury magnetohydrodynamic test-bed (MHD) Moscow Power Engineering Institute (MPEI) - Joint Institute for High Temperatures of the Russian Academy of Sciences (JIHT RAS). The probe measurement technique was used in the flow. Profiles of averaged velocity and averaged temperature, as well as profiles of temperature pulsations in the axial planes of the channel cross-section, are obtained; the distribution of the dimensionless wall temperature along the perimeter unfolding of the channel in the section and along the length of the channel. A significant effect of thermogravitational convection (TGC), which leads to unexpected effects, is found. At the downflow in a magnetic field, in some modes, low-frequency pulsations of anomalously high intensity occur.

The Joint European Torus (JET)

NASA Astrophysics Data System (ADS)

Rebut, Paul-Henri

2017-02-01

This paper addresses the history of JET, the Tokamak that reached the highest performances and the experiment that so far came closest to the eventual goal of a fusion reactor. The reader must be warned, however, that this document is not a comprehensive study of controlled thermonuclear fusion or even of JET. The next step on this road, the ITER project, is an experimental reactor. Actually, several prototypes will be required before a commercial reactor can be built. The fusion history is far from been finalised. JET is still in operation some 32 years after the first plasma and still has to provide answers to many questions before ITER takes the lead on research. Some physical interpretations of the observed phenomena, although coherent, are still under discussion. This paper also recalls some basic physics concepts necessary to the understanding of confinement: a knowledgeable reader can ignore these background sections. This fascinating story, comprising successes and failures, is imbedded in the complexities of twentieth and the early twenty-first centuries at a time when world globalization is evolving and the future seems loaded with questions. The views here expressed on plasma confinement are solely those of the author. This is especially the case for magnetic turbulence, for which other scientists may have different views.

Investigating the Neutral-Gas Manometers in the Wendelstein 7-X Experimental Fusion Reactor

NASA Astrophysics Data System (ADS)

Maisano-Brown, Jeannette; Wenzel, Uwe; Sunn-Pederson, Thomas

2017-01-01

The neutral-gas manometer is a powerful diagnostic tool used in the Wendelstein 7-X stellarator, a magnetized fusion experiment located in Germany. The Wendelstein, produced at a cost of 1.2 billion euros, and 20 years in the making, had its first experimental results in Winter 2016. Initial findings exceeded expectations but further study is still necessary. The particular instrument we examined was a hot-cathode ionization gauge, critical for attaining a quality in-vessel environment and a stable plasma. However, after the winter operation of Wendelstein, we found that some of the gauges had failed the six-second (maximum) plasma runs. Wendelstein is on track for 30-minute operations within three years, so it has become of utmost importance to scrutinize gauge design claims. We therefore subjected the devices to high magnetic field, input current, and temperature, as well as to long operational periods. Our results confirmed that the manometer cannot survive a 30-minute run. Though our findings did motivate promising recommendations for design improvement and for further experimentation so that the gauge can be ready for upcoming operations in Summer 2017 and eventual installment in ITER, the International Thermonuclear Experimental Reactor, currently under construction. This research was graciously supported by the Max Planck Institute and the MIT-Germany Initiative.

Dynamic Confinement of ITER Plasma by O-Mode Driver at Electron Cyclotron Frequency Range

NASA Astrophysics Data System (ADS)

Stefan, V. Alexander

2009-05-01

A low B-field side launched electron cyclotron O-Mode driver leads to the dynamic rf confinement, in addition to rf turbulent heating, of ITER plasma. The scaling law for the local energy confinement time τE is evaluated (τE ˜ 3neTe/2Q, where (3/2) neTe is the local plasma thermal energy density and Q is the local rf turbulent heating rate). The dynamics of unstable dissipative trapped particle modes (DTPM) strongly coupled to Trivelpiece-Gould (T-G) modes is studied for gyrotron frequency 170GHz; power˜24 MW CW; and on-axis B-field ˜ 10T. In the case of dynamic stabilization of DTPM turbulence and for the heavily damped T-G modes, the energy confinement time scales as τE˜(I0)-2, whereby I0(W/m^2) is the O-Mode driver irradiance. R. Prater et. al., Nucl. Fusion 48, No 3 (March 2008). E. P. Velikhov, History of the Russian Tokamak and the Tokamak Thermonuclear Fusion Research Worldwide That Led to ITER (Documentary movie; Stefan Studios Int'l, La Jolla, CA, 2008; E. P. Velikhov, V. Stefan.) M N Rosenbluth, Phys. Scr. T2A 104-109 1982 B. B. Kadomtsev and O. P. Pogutse, Nucl. Fusion 11, 67 (1971).

Development of Field-Reversed Configuration Plasma Gun Formation Techniques for Magnetized Target Fusion

NASA Astrophysics Data System (ADS)

Lynn, Alan; Gilmore, Mark; Wynkoop, Tyler; Intrator, Thomas; Weber, Thomas

2012-10-01

Magnetized Target Fusion (MTF) is an innovative approach for a relatively fast and cheap path to the production of fusion energy that utilizes magnetic confinement to assist in the compression of a hot plasma to thermonuclear conditions by an external driver. Los Alamos National Laboratory (LANL) is currently pursing demonstration of the MTF concept via compression of an FRC (field-reversed configuration) plasma by a metal liner z-pinch in conjunction with the Air Force Research Laboratory in Albuquerque, NM. A key physics issue for the FRC as an MTF target lies in the initial pre-ionization (PI) stage. The PI formation process determines the amount of magnetic flux that can be trapped to form the FRC. This trapped flux plays an important role in the FRC's final equilibrium, transport, and stability properties. It also provides the route to greatest potential gains in FRC lifetime, which is essential to provide enough time to translate and compress the FRC effectively. In conjunction with LANL we plan to test and characterize a new system to improve the initial PI plasma formation. This system will use an array of plasma guns to form the initial plasma. Initial characterization of the plasma gun behavior will be presented.

A Burning Plasma Experiment: the role of international collaboration

NASA Astrophysics Data System (ADS)

Prager, Stewart

2003-04-01

The world effort to develop fusion energy is at the threshold of a new stage in its research: the investigation of burning plasmas. A burning plasma is self-heated. The 100 million degree temperature of the plasma is maintained by the heat generated by the fusion reactions themselves, as occurs in burning stars. The fusion-generated alpha particles produce new physical phenomena that are strongly coupled together as a nonlinear complex system, posing a major plasma physics challenge. Two attractive options are being considered by the US fusion community as burning plasma facilities: the international ITER experiment and the US-based FIRE experiment. ITER (the International Thermonuclear Experimental Reactor) is a large, power-plant scale facility. It was conceived and designed by a partnership of the European Union, Japan, the Soviet Union, and the United States. At the completion of the first engineering design in 1998, the US discontinued its participation. FIRE (the Fusion Ignition Research Experiment) is a smaller, domestic facility that is at an advanced pre-conceptual design stage. Each facility has different scientific, programmatic and political implications. Selecting the optimal path for burning plasma science is itself a challenge. Recently, the Fusion Energy Sciences Advisory Committee recommended a dual path strategy in which the US seek to rejoin ITER, but be prepared to move forward with FIRE if the ITER negotiations do not reach fruition by July, 2004. Either the ITER or FIRE experiment would reveal the behavior of burning plasmas, generate large amounts of fusion power, and be a huge step in establishing the potential of fusion energy to contribute to the world's energy security.

DOE Office of Scientific and Technical Information (OSTI.GOV)

HERRON, ISOM H

Executive summary Two important general problems of interest in plasma physics that may be addressed successfully by Magnetohydrodynamics (MHD) are: (1) Find magnetic field configurations capable of confining a plasma in equilibrium. (2) Study the stability properties of each such an equilibrium. It is often found that the length scale of many instabilities and waves that are able to grow or propagate in a system, are comparable with plasma size, such as in magnetically confined thermonuclear plasmas or in astrophysical accretion disks. Thus MHD is able to provide a good description of such large-scale disturbances. The Magnetorotational instability (MRI) ismore » one particular instance of a potential instability. The project involved theoretical work on fundamental aspects of plasma physics. Researchers at the Princeton Plasma Physics Laboratory (PPPL) began to perform a series of liquid metal Couette flow experiments between rotating cylinders. Their purpose was to produce MRI, which they had predicted theoretically 2002, but was only observed in the laboratory since this project began. The personnel on the project consisted of three persons: (1) The PI, who was partially supported on the budget during each of four summers 2005-2008. (2) Two graduate research assistants, who worked consecutively on the project throughout the years 2005-2009. As a result, the first student, Fritzner Soliman, obtained an M.S. degree in 2006; the second student, Pablo Suarez obtained the Ph.D. degree in 2009. The work was in collaboration with scientists in Princeton, periodic trips were made by the PI as part of the project. There were 4 peer-reviewed publications and one book produced.« less

National Low-Level Waste Management Program Radionuclide Report Series. Volume 10, Nickel-63

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carboneau, M.L.; Adams, J.P.

1995-02-01

This report outlines the basic radiological, chemical, and physical characteristics of nickel-63 ({sup 63}Ni) and examines how these characteristics affect the behavior of {sup 63}Ni in various environmental media, such as soils, groundwater, plants, animals, the atmosphere, and the human body. Discussions also include methods of {sup 63}Ni production, waste types, and waste forms that contain {sup 63}Ni. The primary source of {sup 63}Ni in the environment has been low-level radioactive waste material generated as a result of neutron activation of stable {sup 62}Ni that is present in the structural components of nuclear reactor vessels. {sup 63}Ni enters the environmentmore » from the dismantling activities associated with nuclear reactor decommissioning. However, small amounts of {sup 63}Ni have been detected in the environment following the testing of thermonuclear weapons in the South Pacific. Concentrations as high as 2.7 Bq{sup a} per gram of sample (or equivalently 0.0022 parts per billion) were observed on Bikini Atoll (May 1954). {sup 63}Ni was not created as a fission product species (e.g., from {sup 235}U or {sup 239}Pu fissions), but instead was produced as a result of neutron capture in {sup 63}Ni, a common nickel isotope present in the stainless steel components of nuclear weapons (e.g., stainless-304 contains {approximately}9% total Ni or {approximately}0.3% {sup 63}Ni).« less

Conversion of a room temperature NaK loop to a high temperature MHD facility for Li/V blanket testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reed, C.B.; Haglund, R.C.; Miller, M.E.

1996-12-31

The Vanadium/Lithium system has been the recent focus of ANL`s Blanket Technology Program, and for the last several years, ANL`s Liquid Metal Blanket activities have been carried out in direct support of the ITER (International Thermonuclear Experimental Reactor) breeding blanket task area. A key feasibility issue for the ITER Vanadium/Lithium breeding blanket is the development of insulator coatings. Design calculations, Hua and Gohar, show that an electrically insulating layer is necessary to maintain an acceptably low magnetohydrodynamic (MHD) pressure drop in the current ITER design. Consequently, the decision was made to convert Argonne`s Liquid Metal EXperiment (ALEX) from a 200{degree}Cmore » NaK facility to a 350{degree}C lithium facility. The upgraded facility was designed to produce MHD pressure drop data, test section voltage distributions, and heat transfer data for mid-scale test sections and blanket mockups at Hartmann numbers (M) and interaction parameters (N) in the range of 10{sup 3} to 10{sup 5} in lithium at 350{degree}C. Following completion of the upgrade work, a short performance test was conducted, followed by two longer, multiple-hour, MHD tests, all at 230{degree}C. The modified ALEX facility performed up to expectations in the testing. MHD pressure drop and test section voltage distributions were collected at Hartmann numbers of 1000. 4 refs., 2 figs.« less

The Physics of Advanced High-Gain Targets for Inertial Fusion Energy

NASA Astrophysics Data System (ADS)

Perkins, L. John

2010-11-01

In ca. 2011-2012, the National Ignition Facility is poised to demonstrate fusion ignition and gain in the laboratory for the first time. This key milestone in the development of inertial confinement fusion (ICF) can be expected to engender interest in the development of inertial fusion energy (IFE) and expanded efforts on a number of advanced targets that may achieve high fusion energy gain at lower driver energies. In this tutorial talk, we will discuss the physics underlying ICF ignition and thermonuclear burn, examine the requirements for high gain, and outline candidate R&D programs that will be required to assess the performance of these target concepts under various driver systems including lasers, heavy-ions and pulsed power. Such target concepts include those operating by fast ignition, shock ignition, impact ignition, dual-density, magnetically-insulated, one- and two-sided drive, etc., some of which may have potential to burn advanced, non-DT fusion fuels. We will then delineate the role of such targets in their application to the production of high average fusion power. Here, systems studies of IFE economics suggest that we should strive for target fusion gains of around 100 at drive energies of 1MJ, together with corresponding rep-rates of up to 10Hz and driver electrical efficiencies around 15%. In future years, there may be exciting opportunities to study such ``innovative confinement concepts'' with prospects of fielding them on facilities such as NIF to obtain high fusion energy gains on a single shot basis.

The effects of Q-nuclei on stellar burning

NASA Astrophysics Data System (ADS)

Boyd, R. N.; Turner, R. E.; Sur, B.; Rybarcyk, L.; Joseph, C.

1985-01-01

The effects of anomalous nuclei, Q-nuclei, on stellar burning are examined. The baryon binding energies, beta-decay properties, and thermonuclear reaction rates for the Q-nuclei suggest they could catalyze a cycle in which four protons are combined to form a 4He nucleus. The properties required of the Q-nuclei for them to solve the solar neutrino problem are determined. A solar modelling calculation was performed with Q-nuclei included, and several interesting results therefrom are compared to observations. Finally the solar neutrino detection rates for 71Ga and 115In detectors, in addition to that for 37Cl, are estimated when Q-nuclei are included in the solar burning.

Fusion power for space propulsion.

NASA Technical Reports Server (NTRS)

Roth, R.; Rayle, W.; Reinmann, J.

1972-01-01

Principles of operation, interplanetary orbit-to-orbit mission capabilities, technical problems, and environmental safeguards are examined for thermonuclear fusion propulsion systems. Two systems examined include (1) a fusion-electric concept in which kinetic energy of charged particles from the plasma is converted into electric power (for accelerating the propellant in an electrostatic thrustor) by the van de Graaf generator principle and (2) the direct fusion rocket in which energetic plasma lost from the reactor has a suitable amount of added propellant to obtain the optimum exhaust velocity. The deuterium-tritium and the deuterium/helium-3 reactions are considered as suitable candidates, and attention is given to problems of cryogenic refrigeration systems, magnet shielding, and high-energy particle extraction and guidance.

New methods to detect particle velocity and mass flux in arc-heated ablation/erosion facilities

NASA Technical Reports Server (NTRS)

Brayton, D. B.; Bomar, B. W.; Seibel, B. L.; Elrod, P. D.

1980-01-01

Arc-heated flow facilities with injected particles are used to simulate the erosive and ablative/erosive environments encountered by spacecraft re-entry through fog, clouds, thermo-nuclear explosions, etc. Two newly developed particle diagnostic techniques used to calibrate these facilities are discussed. One technique measures particle velocity and is based on the detection of thermal radiation and/or chemiluminescence from the hot seed particles in a model ablation/erosion facility. The second technique measures a local particle rate, which is proportional to local particle mass flux, in a dust erosion facility by photodetecting and counting the interruptions of a focused laser beam by individual particles.

Linus cycle calculations including plasma transport and resistive flux loss in an incompressible liner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quimby, D.C.; Hoffman, A.L.; Vlases, G.C.

1980-08-01

In the LINUS fusion reactor concept, a rotating liquid metal liner is used for reversible mechanical compression of thermonuclear plasmas, where a vacuum field buffer zone is used between the plasma and wall to reduce transport losses. A one-dimensional plasma transport and burn code, including incompressible liner dynamics with heat transfer and temperature dependent flux diffusion in the liquid metal, is used to model LINUS cycles. The effects of compressibility are treated as a perturbation. Numerical coefficients are derived for simple LINUS scaling laws. The particular case of plasma contact with the liquid metal is studied to determine the effectmore » on LINUS performance.« less

Comparison and analysis of the results of direct-driven targets implosion

NASA Astrophysics Data System (ADS)

Demchenko, N. N.; Dolgoleva, G. V.; Gus'kov, S. Yu; Kuchugov, P. A.; Rozanov, V. B.; Stepanov, R. V.; Zmitrenko, N. V.; Yakhin, R. A.

2017-10-01

The article presents calculation results, which were received for the implosion of the typical cryogenic thermonuclear direct-drive targets that are intended for use at the OMEGA facility, NIF and Russian laser facility. The compression and burning characteristics, which were obtained using various numerical codes of different scientific groups, are compared. The data indicate good agreement between the numerical results. Various sources of target irradiation inhomogeneity and their influence on the implosion parameters are considered. The nominal scales of these disturbances for various facilities are close to each other. The main negative effect on the efficiency of compression and burning is due to the accidental offset of the target from the center of the chamber.

Formation and sustainment of internal transport barriers in the International Thermonuclear Experimental Reactor with the baseline heating mixa)

NASA Astrophysics Data System (ADS)

Poli, Francesca M.; Kessel, Charles E.

2013-05-01

Plasmas with internal transport barriers (ITBs) are a potential and attractive route to steady-state operation in ITER. These plasmas exhibit radially localized regions of improved confinement with steep pressure gradients in the plasma core, which drive large bootstrap current and generate hollow current profiles and negative magnetic shear. This work examines the formation and sustainment of ITBs in ITER with electron cyclotron heating and current drive. The time-dependent transport simulations indicate that, with a trade-off of the power delivered to the equatorial and to the upper launcher, the sustainment of steady-state ITBs can be demonstrated in ITER with the baseline heating configuration.

Scaling laws for ignition at the National Ignition Facility from first principles.

PubMed

Cheng, Baolian; Kwan, Thomas J T; Wang, Yi-Ming; Batha, Steven H

2013-10-01

We have developed an analytical physics model from fundamental physics principles and used the reduced one-dimensional model to derive a thermonuclear ignition criterion and implosion energy scaling laws applicable to inertial confinement fusion capsules. The scaling laws relate the fuel pressure and the minimum implosion energy required for ignition to the peak implosion velocity and the equation of state of the pusher and the hot fuel. When a specific low-entropy adiabat path is used for the cold fuel, our scaling laws recover the ignition threshold factor dependence on the implosion velocity, but when a high-entropy adiabat path is chosen, the model agrees with recent measurements.

ITER Magnet Feeder: Design, Manufacturing and Integration

NASA Astrophysics Data System (ADS)

CHEN, Yonghua; ILIN, Y.; M., SU; C., NICHOLAS; BAUER, P.; JAROMIR, F.; LU, Kun; CHENG, Yong; SONG, Yuntao; LIU, Chen; HUANG, Xiongyi; ZHOU, Tingzhi; SHEN, Guang; WANG, Zhongwei; FENG, Hansheng; SHEN, Junsong

2015-03-01

The International Thermonuclear Experimental Reactor (ITER) feeder procurement is now well underway. The feeder design has been improved by the feeder teams at the ITER Organization (IO) and the Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP) in the last 2 years along with analyses and qualification activities. The feeder design is being progressively finalized. In addition, the preparation of qualification and manufacturing are well scheduled at ASIPP. This paper mainly presents the design, the overview of manufacturing and the status of integration on the ITER magnet feeders. supported by the National Special Support for R&D on Science and Technology for ITER (Ministry of Public Security of the People's Republic of China-MPS) (No. 2008GB102000)

Di(cyanate Ester) Networks Based on Alternative Fluorinated Bisphenols with Extremely Low Water Uptake

DTIC Science & Technology

2013-11-01

radomes6  to magnet casings  for  thermonuclear  fusion  reactors7,8  and  support  structures   for  interplanetary  space  probes.9    These  properties...because  the  conversion  is  relatively  easy  to  quantify via methods such as FT‐IR spectroscopy,17 investiga‐ tions  of  structure ‐property...the  high‐temperature  resistance  and  mechanical  stiffness  associated with aromatic content, which  limits  their poten‐ tial  for high

Mushrooming vulnerability to EMP

NASA Astrophysics Data System (ADS)

Lerner, E. J.

1984-08-01

The electromagnetic pulse (EMP) generated by a single thermonuclear bomb detonated above the continental U.S. could set up electrical fields of 50 kV/m over nearly all of North America. Since the progressively microminiaturized integrated circuits of current military and civilian electronics become more vulnerable with decreasing circuit element size, even shield-protected chips can now be destroyed by the substantially shield-dampened EMP pulses. It is noted as a source of special concern that, as nuclear weapons have evolved, the EMP characteristically generated by them has shifted to increasingly shorter wavelengths, requiring significant redesign of EMP shields devised a decade or more ago. The surge arresters currently employed may not react sufficiently rapidly for existing weapons.

Hydrogen transport behavior of beryllium

NASA Astrophysics Data System (ADS)

Anderl, R. A.; Hankins, M. R.; Longhurst, G. R.; Pawelko, R. J.; Macaulay-Newcombe, R. G.

1992-12-01

Beryllium is being evaluated for use as a plasma-facing material in the International Thermonuclear Experimental Reactor (ITER). One concern in the evaluation is the retention and permeation of tritium implanted into the plasma-facing surface. We performed laboratory-scale studies to investigate mechanisms that influence hydrogen transport and retention in beryllium foil specimens of rolled powder metallurgy product and rolled ingot cast beryllium. Specimen characterization was accomplished using scanning electron microscopy, Auger electron spectroscopy, and Rutherford backscattering spectrometry (RBS) techniques. Hydrogen transport was investigated using ion-beam permeation experiments and nuclear reaction analysis (NRA). Results indicate that trapping plays a significant role in permeation, re-emission, and retention, and that surface processes at both upstream and downstream surfaces are also important.

Outbursts in Symbiotic Binaries

NASA Technical Reports Server (NTRS)

Mushotzky, Richard (Technical Monitor); Kenyon, Scott J.

2003-01-01

Two models have been proposed for the outbursts of symbiotic stars. In the thermonuclear model, outbursts begin when the hydrogen burning shell of a hot white dwarf reaches a critical mass. After a rapid increase in the luminosity and effective temperature, the white dwarf evolves at constant luminosity to lower effective temperatures, remains at optical maximum for several years, and then returns to quiescence along a white dwarf cooling curve. In disk instability models, the brightness rises when the accretion rate from the disk onto the central white dwarf abruptly increases by factors of 5-20. After a few month to several year period at maximum, both the luminosity and the effective temperature of the disk decline as the system returns to quiescence.

Detection of circumstellar material in a normal type Ia supernova.

PubMed

Patat, F; Chandra, P; Chevalier, R; Justham, S; Podsiadlowski, Ph; Wolf, C; Gal-Yam, A; Pasquini, L; Crawford, I A; Mazzali, P A; Pauldrach, A W A; Nomoto, K; Benetti, S; Cappellaro, E; Elias-Rosa, N; Hillebrandt, W; Leonard, D C; Pastorello, A; Renzini, A; Sabbadin, F; Simon, J D; Turatto, M

2007-08-17

Type Ia supernovae are important cosmological distance indicators. Each of these bright supernovae supposedly results from the thermonuclear explosion of a white dwarf star that, after accreting material from a companion star, exceeds some mass limit, but the true nature of the progenitor star system remains controversial. Here we report the spectroscopic detection of circumstellar material in a normal type Ia supernova explosion. The expansion velocities, densities, and dimensions of the circumstellar envelope indicate that this material was ejected from the progenitor system. In particular, the relatively low expansion velocities suggest that the white dwarf was accreting material from a companion star that was in the red-giant phase at the time of the explosion.

Beam limiter for thermonuclear fusion devices

DOEpatents

Kaminsky, Manfred S.

1976-01-01

A beam limiter circumscribes the interior surface of a vacuum vessel to inhibit collisions of contained plasma and the vessel walls. The cross section of the material making up the limiter has a flatsided or slightly concave portion of increased width towards the plasma and portions of decreased width towards the interior surface of the vessel. This configuration is designed to prevent a major fraction of the material sputtered, vaporized and blistered from the limiter from reaching the plasma. It also allows adequate heat transfer from the wider to the narrower portions. The preferred materials for the beam limiter are solids of sintered, particulate materials of low atomic number with low vapor pressure and low sputtering and blistering yields.

Performance of High-Convergence, Layered DT Implosions on Power-Scaling Experiments at National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smalyuk, V. A.; Atherton, L. J.; Benedetti, L. R.

The radiation-driven, low-adiabat, cryogenic DT layered plastic capsule implosions were carried out on the National Ignition Facility (NIF) to study the sensitivity of performance to peak power and drive duration. An implosion with extended drive and at reduced peak power of 350 TW achieved the highest compression with fuel areal density of ~1.3±0.1 g/cm 2, representing a significant step from previously measured ~1.0 g/cm 2 toward a goal of 1.5 g/cm 2. Moreover, for future experiments will focus on understanding and mitigating hydrodynamic instabilities and mix, and improving symmetry required to reach the threshold for thermonuclear ignition on NIF.

Performance of High-Convergence, Layered DT Implosions on Power-Scaling Experiments at National Ignition Facility

DOE PAGES

Smalyuk, V. A.; Atherton, L. J.; Benedetti, L. R.; ...

2013-10-19

The radiation-driven, low-adiabat, cryogenic DT layered plastic capsule implosions were carried out on the National Ignition Facility (NIF) to study the sensitivity of performance to peak power and drive duration. An implosion with extended drive and at reduced peak power of 350 TW achieved the highest compression with fuel areal density of ~1.3±0.1 g/cm 2, representing a significant step from previously measured ~1.0 g/cm 2 toward a goal of 1.5 g/cm 2. Moreover, for future experiments will focus on understanding and mitigating hydrodynamic instabilities and mix, and improving symmetry required to reach the threshold for thermonuclear ignition on NIF.

A route to the brightest possible neutron source?

PubMed

Taylor, Andrew; Dunne, Mike; Bennington, Steve; Ansell, Stuart; Gardner, Ian; Norreys, Peter; Broome, Tim; Findlay, David; Nelmes, Richard

2007-02-23

We review the potential to develop sources for neutron scattering science and propose that a merger with the rapidly developing field of inertial fusion energy could provide a major step-change in performance. In stark contrast to developments in synchrotron and laser science, the past 40 years have seen only a factor of 10 increase in neutron source brightness. With the advent of thermonuclear ignition in the laboratory, coupled to innovative approaches in how this may be achieved, we calculate that a neutron source three orders of magnitude more powerful than any existing facility can be envisaged on a 20- to 30-year time scale. Such a leap in source power would transform neutron scattering science.

Magnetic Flux Compression Concept for Nuclear Pulse Propulsion and Power

NASA Technical Reports Server (NTRS)

Litchford, Ronald J.

2000-01-01

The desire for fast, efficient interplanetary transport requires propulsion systems having short acceleration times and very high specific impulse attributes. Unfortunately, most highly efficient propulsion systems which are within the capabilities of present day technologies are either very heavy or yield very low impulse such that the acceleration time to final velocity is too long to be of lasting interest, One exception, the nuclear thermal thruster, could achieve the desired acceleration but it would require inordinately large mass ratios to reach the range of desired final velocities. An alternative approach, among several competing concepts that are beyond our modern technical capabilities, is a pulsed thermonuclear device utilizing microfusion detonations. In this paper, we examine the feasibility of an innovative magnetic flux compression concept for utilizing microfusion detonations, assuming that such low yield nuclear bursts can be realized in practice. In this concept, a magnetic field is compressed between an expanding detonation driven diamagnetic plasma and a stationary structure formed from a high temperature superconductor (HTSC). In general, we are interested in accomplishing two important functions: (1) collimation of a hot diamagnetic plasma for direct thrust production; and (2) pulse power generation for dense plasma ignition. For the purposes of this research, it is assumed that rnicrofusion detonation technology may become available within a few decades, and that this approach could capitalize on recent advances in inertial confinement fusion ICF) technologies including magnetized target concepts and antimatter initiated nuclear detonations. The charged particle expansion velocity in these detonations can be on the order of 10 (exp 6)- 10 (exp 7) meters per second, and, if effectively collimated by a magnetic nozzle, can yield the Isp and the acceleration levels needed for practical interplanetary spaceflight. The ability to ignite pure fusion micro-bursts with reasonable levels of input energy is an equally challenging scientific problem. It remains to be seen, however, whether an effective ignition driver can be developed which meets the requirements for practical spaceflight application (namely high power density, compactness, low weight, and low cost). In this paper, system level performance and design issues are examined including generator performance, magnetic flux compression processes, magnetic diffusion processes, high temperature superconductor (HTSC) material properties, plasmadynamic processes, detonation plasma expansion processes, magnetohydrodynamic instabilities, magnetic nozzle performance, and thrust production performance. Representative generator performance calculations based on a simplified skin layer formulation are presented as well as the results of exploratory small-scale laboratory experiments on magnetic flux diffusion in HTSC materials. In addition, planned follow-on scientific feasibility experiments are described which utilize high explosive detonations and high energy gas discharges to simulate the plasma conditions associated with thermonuclear micro-detonations.

5 CFR 470.201 - Purposes of research programs.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 5 Administrative Personnel 1 2014-01-01 2014-01-01 false Purposes of research programs. 470.201... PERSONNEL MANAGEMENT RESEARCH PROGRAMS AND DEMONSTRATIONS PROJECTS Regulatory Requirements Pertaining to Research Programs § 470.201 Purposes of research programs. The purposes of research programs undertaken...

5 CFR 470.201 - Purposes of research programs.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Purposes of research programs. 470.201... PERSONNEL MANAGEMENT RESEARCH PROGRAMS AND DEMONSTRATIONS PROJECTS Regulatory Requirements Pertaining to Research Programs § 470.201 Purposes of research programs. The purposes of research programs undertaken...

USAF Summer Research Program - 1993 Graduate Student Research Program Final Reports, Volume 8, Phillips Laboratory

DTIC Science & Technology

1994-12-01

Research Program Phillips Laboratory Kirtland Air Force Base Albuquerque, New Mexico Sponsored by: Air ...Summer Research Program Phillips Laboratory Sponsored by. Air Force Office of Scientific Research Kirtland Air Force Base, Albuquerque, New Mexico...UNITED STATES AIR FORCE SUMMER RESEARCH PROGRAM -- 1993 SUMMER RESEARCH PROGRAM FINAL REPORTS VOLUME 8

Stellar explosions from accreting white dwarfs

NASA Astrophysics Data System (ADS)

Moore, Kevin L.

Unstable thermonuclear burning on accreting white dwarfs (WDs) can lead to a wide variety of outcomes, and induce shock waves in several contexts. In classical and recurrent novae, a WD accreting hydrogen-rich material from a binary companion can experience thermonuclear runaways, ejecting mass into the interstellar/circumbinary environment at ~1000 km/s. This highly supersonic ejecta drives shock waves into the interstellar gas which may be relevant for sweeping out gas from globular clusters or forming circumstellar absorption regions in interacting supernovae. While runaway nuclear burning in novae releases enough energy for these objects to brighten by a factor of ~10 4 over roughly a weeklong outburst, it does not become dynamically unstable. In contrast, certain helium accretion scenarios may allow for dynamical burning modes, in part due to the higher temperature sensitivity of helium burning reactions and larger accreted envelopes. The majority of this thesis involves such dynamical burning modes, specifically detonations - shock waves sustained by nuclear energy release behind the shock front. We investigate when steady-state detonations are realizable in accreted helium layers on WDs, and model their strength and burning products using both semi-analytic and numerical models. We find the minimum helium layer thickness that will sustain a steady laterally propagating detonation and show that it depends on the density and composition of the helium layer, specifically 12 C and 16O. Though gravitationally unbound, the ashes still have unburned helium (~80% in the thinnest cases) and only reach up to heavy elements such as 40Ca, 44Ti, 48Cr, and 52Fe. It is rare for these thin shells to generate large amounts of radioactive isotopes necessary to power light curves, such as 56Ni. This has important implications on whether the unbound helium burning ashes may create faint and fast peculiar supernovae or events with virtually no radioactivity, as well as on off-center ignition of the underlying WD in the double detonation scenario for Type Ia supernovae.

CONDITIONS FOR SUCCESSFUL HELIUM DETONATIONS IN ASTROPHYSICAL ENVIRONMENTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holcomb, Cole; Guillochon, James; De Colle, Fabio

2013-07-01

Several models for Type Ia-like supernova events rely on the production of a self-sustained detonation powered by nuclear reactions. In the absence of hydrogen, the fuel that powers these detonations typically consists of either pure helium (He) or a mixture of carbon and oxygen (C/O). Studies that systematically determine the conditions required to initiate detonations in C/O material exist, but until now no analogous investigation of He matter has been conducted. We perform one-dimensional reactive hydrodynamical simulations at a variety of initial density and temperature combinations and find critical length scales for the initiation of He detonations that range betweenmore » 1 and 10{sup 10} cm. A simple estimate of the length scales over which the total consumption of fuel will occur for steady-state detonations is provided by the Chapman-Jouguet (CJ) formalism. Our initiation lengths are consistently smaller than the corresponding CJ length scales by a factor of {approx}100, providing opportunities for thermonuclear explosions in a wider range of low-mass white dwarfs (WDs) than previously thought possible. We find that virialized WDs with as little mass as 0.24 M{sub Sun} can be detonated, and that even less massive WDs can be detonated if a sizable fraction of their mass is raised to a higher adiabat. That the initiation length is exceeded by the CJ length implies that certain systems may not reach nuclear statistical equilibrium within the time it takes a detonation to traverse the object. In support of this hypothesis, we demonstrate that incomplete burning will occur in the majority of He WD detonations and that {sup 40}Ca, {sup 44}Ti, or {sup 48}Cr, rather than {sup 56}Ni, is the predominant burning product for many of these events. We anticipate that a measure of the quantity of the intermediate-mass elements and {sup 56}Ni produced in a helium-rich thermonuclear explosion can potentially be used to constrain the nature of the progenitor system.« less

Low mass SN Ia and the late light curve

DOE Office of Scientific and Technical Information (OSTI.GOV)

Colgate, S.A.; Fryer, C.L.; Hand, K.P.

1995-12-31

The late bolometric light curves of type Ia supernovae, when measured accurately over several years, show an exponential decay with a 56d half-life over a drop in luminosity of 8 magnitudes (10 half-lives). The late-time light curve is thought to be governed by the decay of Co{sup 56}, whose 77d half-life must then be modified to account for the observed decay time. Two mechanisms, both relying upon the positron fraction of the Co{sup 56} decay, have been proposed to explain this modification. One explanation requires a large amount of emission at infra-red wavelengths where it would not be detected. Themore » other explanation has proposed a progressive transparency or leakage of the high energy positrons (Colgate, Petschek and Kriese, 1980). For the positrons to leak out of the expanding nebula at the required rate necessary to produce the modified 56d exponential, the mass of the ejecta from a one foe (10{sup 51} erg in kinetic energy) explosion must be small, M{sub ejec} = 0.4M{sub {circle_dot}} with M{sub ejec} {proportional_to} KE{sup 0.5}. Thus, in this leakage explanation, any reasonable estimate of the total energy of the explosion requires that the ejected mass be very much less than the Chandrasekhar mass of 1.4M{sub {circle_dot}}. This is very difficult to explain with the ``canonical`` Chandrasekhar-mass thermonuclear explosion that disintegrates the original white dwarf star. This result leads us to pursue alternate mechanisms of type Ia supernovae. These mechanisms include sub-Chandrasekhar thermonuclear explosions and the accretion induced collapse of Chandrasekhar mass white dwarfs. We will summarize the advantages and disadvantages of both mechanisms with considerable detail spent on our new accretion induced collapse simulations. These mechanisms lead to lower Ni{sup 56} production and hence result in type Ia supernovae with luminosities decreased down to {approximately} 50% that predicted by the ``standard`` model.« less

The Impact of Nuclear Reaction Rate Uncertainties on the Evolution of Core-collapse Supernova Progenitors

NASA Astrophysics Data System (ADS)

Fields, C. E.; Timmes, F. X.; Farmer, R.; Petermann, I.; Wolf, William M.; Couch, S. M.

2018-02-01

We explore properties of core-collapse supernova progenitors with respect to the composite uncertainties in the thermonuclear reaction rates by coupling the probability density functions of the reaction rates provided by the STARLIB reaction rate library with MESA stellar models. We evolve 1000 models of 15{M}ȯ from the pre-main sequence to core O-depletion at solar and subsolar metallicities for a total of 2000 Monte Carlo stellar models. For each stellar model, we independently and simultaneously sample 665 thermonuclear reaction rates and use them in a MESA in situ reaction network that follows 127 isotopes from 1H to 64Zn. With this framework we survey the core mass, burning lifetime, composition, and structural properties at five different evolutionary epochs. At each epoch we measure the probability distribution function of the variations of each property and calculate Spearman rank-order correlation coefficients for each sampled reaction rate to identify which reaction rate has the largest impact on the variations on each property. We find that uncertainties in the reaction rates of {}14{{N}}{({{p}},γ )}15{{O}}, triple-α, {}12{{C}}{(α ,γ )}16{{O}}, 12C(12C,p)23Na, 12C(16O, p)27Al, 16O(16O,n)31S, 16O(16O, p)31P, and 16O(16O,α)28Si dominate the variations of the properties surveyed. We find that variations induced by uncertainties in nuclear reaction rates grow with each passing phase of evolution, and at core H-, He-depletion they are of comparable magnitude to the variations induced by choices of mass resolution and network resolution. However, at core C-, Ne-, and O-depletion, the reaction rate uncertainties can dominate the variation, causing uncertainty in various properties of the stellar model in the evolution toward iron core-collapse.

Examination of the role of the O14(α,p)F17 reaction rate in type-I x-ray bursts

NASA Astrophysics Data System (ADS)

Hu, J.; He, J. J.; Parikh, A.; Xu, S. W.; Yamaguchi, H.; Kahl, D.; Ma, P.; Su, J.; Wang, H. W.; Nakao, T.; Wakabayashi, Y.; Teranishi, T.; Hahn, K. I.; Moon, J. Y.; Jung, H. S.; Hashimoto, T.; Chen, A. A.; Irvine, D.; Lee, C. S.; Kubono, S.

2014-08-01

The O14(α,p)F17 reaction is one of the key reactions involved in the breakout from the hot-CNO cycle to the rp-process in type-I x-ray bursts (XRBs). The resonant properties in the compound nucleus Ne18 have been investigated through resonant elastic scattering of F17+p. The radioactive F17 beam was separated by the Center for Nuclear Study radioactive ion beam separator (CRIB) and bombarded a thick H2 gas target at 3.6 MeV/nucleon. The recoiling light particles were measured by three ΔE-E silicon telescopes at laboratory angles of θlab≈3∘,10∘, and 18∘. Five resonances at Ex=6.15, 6.28, 6.35, 6.85, and 7.05 MeV were observed in the excitation functions, and their spin-parities have been determined based on an R-matrix analysis. In particular, Jπ=1- was firmly assigned to the 6.15-MeV state which dominates the thermonuclear O14(α ,p)F17 rate below 2 GK. As well, a possible new excited state in Ne18 was observed at Ex=6.85±0.11 MeV with tentative J =0 assignment. This state could be the analog state of the 6.880 MeV (0-) level in the mirror nucleus O18, or a bandhead state (0+) of the six-particle four-hole (6p-4h) band. A new thermonuclear O14(α ,p)F17 rate has been determined, and the astrophysical impact of multiple recent rates has been examined using an XRB model. Contrary to previous expectations, we find only a modest impact on predicted nuclear energy generation rates from using reaction rates differing by up to several orders of magnitude.

High-Q plasmas in the TFTR tokamak

NASA Astrophysics Data System (ADS)

Jassby, D. L.; Barnes, C. W.; Bell, M. G.; Bitter, M.; Boivin, R.; Bretz, N. L.; Budny, R. V.; Bush, C. E.; Dylla, H. F.; Efthimion, P. C.; Fredrickson, E. D.; Hawryluk, R. J.; Hill, K. W.; Hosea, J.; Hsuan, H.; Janos, A. C.; Jobes, F. C.; Johnson, D. W.; Johnson, L. C.; Kamperschroer, J.; Kieras-Phillips, C.; Kilpatrick, S. J.; LaMarche, P. H.; LeBlanc, B.; Mansfield, D. K.; Marmar, E. S.; McCune, D. C.; McGuire, K. M.; Meade, D. M.; Medley, S. S.; Mikkelsen, D. R.; Mueller, D.; Owens, D. K.; Park, H. K.; Paul, S. F.; Pitcher, S.; Ramsey, A. T.; Redi, M. H.; Sabbagh, S. A.; Scott, S. D.; Snipes, J.; Stevens, J.; Strachan, J. D.; Stratton, B. C.; Synakowski, E. J.; Taylor, G.; Terry, J. L.; Timberlake, J. R.; Towner, H. H.; Ulrickson, M.; von Goeler, S.; Wieland, R. M.; Williams, M.; Wilson, J. R.; Wong, K.-L.; Young, K. M.; Zarnstorff, M. C.; Zweben, S. J.

1991-08-01

In the Tokamak Fusion Test Reactor (TFTR) [Plasma Phys. Controlled Fusion 26, 11 (1984)], the highest neutron source strength Sn and D-D fusion power gain QDD are realized in the neutral-beam-fueled and heated ``supershot'' regime that occurs after extensive wall conditioning to minimize recycling. For the best supershots, Sn increases approximately as P1.8b. The highest-Q shots are characterized by high Te (up to 12 keV), Ti (up to 34 keV), and stored energy (up to 4.7 MJ), highly peaked density profiles, broad Te profiles, and lower Zeff. Replacement of critical areas of the graphite limiter tiles with carbon-fiber composite tiles and improved alignment with the plasma have mitigated the ``carbon bloom.'' Wall conditioning by lithium pellet injection prior to the beam pulse reduces carbon influx and particle recycling. Empirically, QDD increases with decreasing pre-injection carbon radiation, and increases strongly with density peakedness [ne(0)/] during the beam pulse. To date, the best fusion results are Sn=5×1016 n/sec, QDD=1.85×10-3, and neutron yield=4.0×1016 n/pulse, obtained at Ip=1.6-1.9 MA and beam energy Eb=95-103 keV, with nearly balanced co- and counter-injected beam power. Computer simulations of supershot plasmas show that typically 50%-60% of Sn arises from beam-target reactions, with the remainder divided between beam-beam and thermonuclear reactions, the thermonuclear fraction increasing with Pb. The simulations predict that QDT=0.3-0.4 would be obtained for the best present plasma conditions, if half the deuterium neutral beams were to be replaced by tritium beams. Somewhat higher values are calculated if D beams are injected into a predominantly tritium target plasma. The projected central beta of fusion alphas is 0.4%-0.6%, a level sufficient for the study of alpha-induced collective effects.

PREFACE: XV Chilean Physics Symposium, 2006

NASA Astrophysics Data System (ADS)

Soto, Leopoldo; Moreno, José; Ávila, Ricardo; Cubillos, Karla

2008-02-01

The Chilean Physics Symposium is the main gathering of Physics in Chile, and its organization is one of the central activities of the Chilean Physical Society (Sociedad Chilena de Física, SOCHIFI). The Symposium assembles the largest number of Chilean and foreign physicists resident in the country. Recent advances in the various research areas in Physics are presented, by researchers from Universities and national research centres. At the same time this is an occasion for the participation of Physics students from both the pre- and post-graduate programs. The Symposium has gathered continuously every two years, since 1978. The organization of the XV symposium was in charge of the Thermonuclear Plasma Department of the Chilean Nuclear Energy Commission, and it took place on 15-17 November 2006, at La Reina Nuclear Studies Centre, in the city of Santiago, Chile. During this symposium the relation of research in Physics with education and with the productive sector in the country was also analysed. During the Symposium, 121 abstracts were submitted, from 255 authors. All authors were invited to submit articles for publication in the Symposium Proceedings. The articles received were reviewed by the Symposium Scientific Committee and by invited peers. The criteria for review focussed on the demand for a consistent piece of research, and a clear statement of results. Most of the articles received report the work of research groups where advanced students and young investigators are prominent. Thanks to their enthusiasm, 52 articles are presented in this issue. We would like to express our appreciation to their authors. Finally, my personal apology is in order regarding my delay in publishing these proceedings. A sequence of personal and professional highly demanding circumstances have been in the way. I would like to thank Journal of Physics: Conference Series for providing very fast publication of the proceedings, having published them online less than 4 weeks after my initial contact with the journal. Leopoldo Soto President, Chilean Physical Society Head of Plasma Department, Chilean Nuclear Energy Commission Editors: Leopoldo Soto, José Moreno, Ricardo Ávila, Karla Cubillos Scientific Committee Physicists from various research institutions, specialty areas, and regions of the country were invited by the Board of SOCHIFI to join the Symposium Scientific Committee, which was formed by: Julio Yánez, Universidad de Antofagasta Sergio del Campo, Pontificia Universidad Católica de Valparaíso Patricio Vargas, Universidad Técnica Federico Santa María Rodrigo Soto, Universidad de Chile Ulrich Volkmann, Pontificia Universidad Católica de Chile Víctor Muñoz, Universidad de Chile Rodrigo Aros, Universidad Andrés Bello Leopoldo Soto (Chairman), Comisión Chilena de Energía Nuclear Luis Huerta, Universidad de Talca Patricio Salgado, Universidad de Concepción Luis Roa, Universidad de Concepción Asticio Vargas, Universidad de la Frontera, Temuco Cristian Martínez, Centro de Estudios Científicos, Valdivia Organizing Commitee Leopoldo Soto (Chairman), Comisión Chilena de Energía Nuclear Erik Herrera, Comisión Chilena de Energía Nuclear José Moreno, Comisión Chilena de Energía Nuclear Andrea Rozas, Comisión Chilena de Energía Nuclear Rodrigo Aros, Universidad Andrés Bello Gonzalo Gutiérrez, Universidad de Chile Executive Board, Chilean Physical Society April 2006 - April 2008 Leopoldo Soto, President Joel Saavedra, Secretary Rodrigo Aros: Treasurer Rodolfo Figueroa: Director Luis Huerta: Director Conference photograph

Theory of supercompression of vapor bubbles and nanoscale thermonuclear fusion

NASA Astrophysics Data System (ADS)

Nigmatulin, Robert I.; Akhatov, Iskander Sh.; Topolnikov, Andrey S.; Bolotnova, Raisa Kh.; Vakhitova, Nailya K.; Lahey, Richard T.; Taleyarkhan, Rusi P.

2005-10-01

This paper provides the theoretical basis for energetic vapor bubble implosions induced by a standing acoustic wave. Its primary goal is to describe, explain, and demonstrate the plausibility of the experimental observations by Taleyarkhan et al. [Science 295, 1868 (2002); Phys. Rev. E 69, 036109 (2004)] of thermonuclear fusion for imploding cavitation bubbles in chilled deuterated acetone. A detailed description and analysis of these data, including a resolution of the criticisms that have been raised, together with some preliminary HYDRO code simulations, has been given by Nigmatulin et al. [Vestnik ANRB (Ufa, Russia) 4, 3 (2002); J. Power Energy 218-A, 345 (2004)] and Lahey et al. [Adv. Heat Transfer (to be published)]. In this paper a hydrodynamic shock (i.e., HYDRO) code model of the spherically symmetric motion for a vapor bubble in an acoustically forced liquid is presented. This model describes cavitation bubble cluster growth during the expansion period, followed by a violent implosion during the compression period of the acoustic cycle. There are two stages of the bubble dynamics process. The first, low Mach number stage, comprises almost all the time of the acoustic cycle. During this stage, the radial velocities are much less than the sound speeds in the vapor and liquid, the vapor pressure is very close to uniform, and the liquid is practically incompressible. This process is characterized by the inertia of the liquid, heat conduction, and the evaporation or condensation of the vapor. The second, very short, high Mach number stage is when the radial velocities are the same order, or higher, than the sound speeds in the vapor and liquid. In this stage high temperatures, pressures, and densities of the vapor and liquid take place. The model presented herein has realistic equations of state for the compressible liquid and vapor phases, and accounts for nonequilibrium evaporation/condensation kinetics at the liquid/vapor interface. There are interacting shock waves in both phases, which converge toward and reflect from the center of the bubble, causing dissociation, ionization, and other related plasma physics phenomena during the final stage of bubble collapse. For a vapor bubble in a deuterated organic liquid (e.g., acetone), during the final stage of collapse there is a nanoscale region (diameter ˜100nm) near the center of the bubble in which, for a fraction of a picosecond, the temperatures and densities are extremely high (˜108K and ˜10g/cm3, respectively) such that thermonuclear fusion may take place. To quantify this, the kinetics of the local deuterium/deuterium (D/D) nuclear fusion reactions was used in the HYDRO code to determine the intensity of the fusion reactions. Numerical HYDRO code simulations of the bubble implosion process have been carried out for the experimental conditions used by Taleyarkhan et al. [Science 295, 1868 (2002); Phys. Rev. E 69, 036109 (2004)] at Oak Ridge National Laboratory. The results show good agreement with the experimental data on bubble fusion that was measured in chilled deuterated acetone.

Supernovae: lights in the darkness

NASA Astrophysics Data System (ADS)

Every year, at the end of the summer, the Section of Physics and Technique of the "Institut Menorquí d'Estudis" and the "Societat Catalana de Física" organize the "Trobades Científiques de la Mediterrània" with the support of several academic institutions. The 2007 edition has been devoted to stellar explosions, the true evolutionary engines of galaxies. Whenever a star explodes, it injects into the interstellar medium a kinetic energy of 1051 erg and between one and several solar masses of newly synthesized elements as a result of the thermonuclear reactions that have taken place within the stellar interior. Two mechanisms are able to provide these enormous amounts of energy: one of them thermonuclear and the other, gravitational. Thermonuclear supernovae are the result of the incineration of a carbon-oxygen white dwarf that is the compact star of a binary stellar system. If the two stars are sufficiently close to each other, the white dwarf accretes matter from its companion, approaches the mass of Chandrasekhar, and ends up exploding. The processes previous to the explosion, the explosion itself, as well as the exact nature of the double stellar system that explodes, are still a matter of discussion. This point is particularly important because these explosions, known as Type Ia Supernovae, are very homogenous and can be used to measure cosmological distances. The most spectacular result obtained, is the discovery of the accelerated expansion of the Universe, but it still feels uncomfortable that such a fundamental result is based on a "measuring system" whose origin and behaviour in time is unknown. At the end of their lives, massive stars generate an iron nucleus that gets unstable when approaching the Chandrasekhar mass. Its collapse gives rise to the formation of a neutron star or a black hole, and the external manifestation of the energy that is released, about a 1053 erg, consists of a Type II or Ib/c supernova, of a Gamma Ray Burst (GRB) or even of both things. From the beginning of the nineties, when CGRO discovered the cosmological character of these phenomena, the GRB have constituted one of the most exciting problems of modern Astrophysics. The stellar end products that leave supernovae, are as interesting as supernovae themselves. On one hand, as we previously said, they completely determine the chemical evolution of the Galaxy, which is fundamental for the formation of planets or, even, for the appearance of life. On the other hand, they leave collapsed objects such as neutron stars and black holes that give rise to a wide range of violent phenomena: x-rays eruptions, microquasars, acceleration of particles to high energies, etc. The goal of this workshop was to bring together scientists with a deep insight into these topics and advanced PhD students, with the purpose of discussing in depth the remaining problems. The organizers are specially grateful to DIUE-Generalitat de Catalunya, Ministerio de Educación y Ciencia, Balearic Island University, Barcelona University, Polythecnical University of Catalonia, Valencia University, CSIC and IFAE for their economical support.

5 CFR 470.205 - Initiation of research programs.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Initiation of research programs. 470.205... PERSONNEL MANAGEMENT RESEARCH PROGRAMS AND DEMONSTRATIONS PROJECTS Regulatory Requirements Pertaining to Research Programs § 470.205 Initiation of research programs. OPM will announce opportunities for research...

5 CFR 470.205 - Initiation of research programs.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 5 Administrative Personnel 1 2014-01-01 2014-01-01 false Initiation of research programs. 470.205... PERSONNEL MANAGEMENT RESEARCH PROGRAMS AND DEMONSTRATIONS PROJECTS Regulatory Requirements Pertaining to Research Programs § 470.205 Initiation of research programs. OPM will announce opportunities for research...

NASA Lewis Research Center/university graduate research program on engine structures

NASA Technical Reports Server (NTRS)

Chamis, C. C.

1985-01-01

NASA Lewis Research Center established a graduate research program in support of the Engine Structures Research activities. This graduate research program focuses mainly on structural and dynamics analyses, computational mechanics, mechanics of composites and structural optimization. The broad objectives of the program, the specific program, the participating universities and the program status are briefly described.

NASA Lewis Research Center/University Graduate Research Program on Engine Structures

NASA Technical Reports Server (NTRS)

Chamis, C. C.

1985-01-01

NASA Lewis Research Center established a graduate research program in support of the Engine Structures Research activities. This graduate research program focuses mainly on structural and dynamics analyses, computational mechanics, mechanics of composites and structural optimization. The broad objectives of the program, the specific program, the participating universities and the program status are briefly described.

LTRC Annual Research Program : Fiscal Year July 1, 2017 - June 30, 2018.

DOT National Transportation Integrated Search

2017-06-01

FHWA Part II SPR Research Program FAP Number SPR-0010(34) & FHWA Funded Research Program & FHWA LTAP Funded Program & FHWA STP Funded Program & Federal & Self-Generated Funded Research Program & Other DOTD Funded Projects

LTRC Annual Research Program : Fiscal Year July 1, 2012-June 30, 2013

DOT National Transportation Integrated Search

2012-06-01

Contents: Budget Recap Sheets; Project Summary Sheets; FHWA Part II SPR Funded Research Program; FHWA IBRD Funded Research Program; FHWA LTAP Funded Program; FHWA STP Funded Technology Transfer & Education Program; State Funded Research Program; Fede...

LTRC annual research program : fiscal year July 1, 2011-June 30, 2012.

DOT National Transportation Integrated Search

2011-06-01

Contents: Budget Recaps Sheets; Project Summary Sheets; FHWA Part II SPR Funded Research Program; FHWA IBRD Funded Research Program; FHWA LTAP Funded Program; FHWA STP Funded Technology Transfer & Education Program; State Funded Research Program; Sel...

Chandra Observations of New X-ray Supernovae

NASA Astrophysics Data System (ADS)

Pooley, David

2016-09-01

We propose to continue our X-ray studies of all types of supernovae (SNe). The Swift satellite ushered in a new era of studying SNe in the X-rays, obtaining densely sampled observations for nearby SNe, both core collapse and thermonuclear (although no Type Ia has been conclusively detected in X-rays). However, the Swift XRT spatial resolution is often not good enough to definitively associate X-ray emission in the direction of the SN with the SN itself. We propose short Chandra observations to alleviate this. These observations will assess the X-ray environment of newly discovered X-ray SNe to determine any possible source confusion or contamination of the SN flux. Our strategy makes the best use of the capabilities of each observatory.

Chandra Observations of New X-ray Supernovae

NASA Astrophysics Data System (ADS)

Pooley, David

2017-09-01

We propose to continue our X-ray studies of all types of supernovae (SNe). The Swift satellite ushered in a new era of studying SNe in the X-rays, obtaining densely sampled observations for nearby SNe, both core collapse and thermonuclear (although no Type Ia has been conclusively detected in X-rays). However, the Swift XRT spatial resolution is often not good enough to definitively associate X-ray emission in the direction of the SN with the SN itself. We propose short Chandra observations to alleviate this. These observations will assess the X-ray environment of newly discovered X-ray SNe to determine any possible source confusion or contamination of the SN flux. Our strategy makes the best use of the capabilities of each observatory.

Chandra Observations of New X-ray Supernovae

NASA Astrophysics Data System (ADS)

Pooley, David

2015-09-01

We propose to continue our X-ray studies of all types of supernovae (SNe). The Swift satellite ushered in a new era of studying SNe in the X-rays, obtaining densely sampled observations for nearby SNe, both core collapse and thermonuclear (although no Type Ia has been conclusively detected in X-rays). However, the Swift XRT spatial resolution is often not good enough to definitively associate X-ray emission in the direction of the SN with the SN itself. We propose short Chandra observations to alleviate this. These observations will assess the X-ray environment of newly discovered X-ray SNe to determine any possible source confusion or contamination of the SN flux. Our strategy makes the best use of the capabilities of each observatory.

Supernovae, supernebulae, and nucleosynthesis

NASA Astrophysics Data System (ADS)

Wheeler, J. Craig; Harkness, Robert P.; Barkat, Zalman; Swartz, Douglas

1986-10-01

Supernova atmosphere calculations continue to show that variants of previously calculated carbon-deflagration models provide a good representation of the maximum light spectra of classical type Ia supernovae including the ultraviolet deficit. Careful consideration of the conditions leading to central thermonuclear runaway of degenerate carbon shows that runaway can, however, lead to detonation and direct conflict with observations. As witnessed by the spectra of type Ib supernovae, massive stars are expected to be the primary source of oxygen. Estimates of the absolute production of oxygen in massive stars suggest that if all stars more massive than ≡12 M_sun; explode as supernovae, oxygen would be overproduced in the solar neighborhood, an effect exacerbated by the recent increase in the reaction rate for 12C(α, γ)16O.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Libby, S B; Sessler, A M

Edward Teller died on September 9, 2003 in Stanford, California at the age of 95. He was both one of the great theoretical physicists of the twentieth century and a leading figure in the development of nuclear weapons and broader defense advocacy. Teller's work in physics, spanning many decades of the twentieth century, includes some of the most fundamental insights in the quantum behaviors of molecules and their spectra, nuclei, surfaces, solid state and spin systems, and plasmas. In the defense arena, Teller is best known for his key insight that made thermonuclear weapons possible. Teller was both a greatmore » scientific collaborator and physics teacher at all levels, known for his openness, generosity, personal warmth, and powerful physical intuition. Many of his graduate students went on to illustrious careers.« less

Analytical model of brittle destruction based on hypothesis of scale similarity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arakcheev, A. S., E-mail: asarakcheev@gmail.com; Lotov, K. V.

2012-08-15

The size distribution of dust particles in thermonuclear (fusion) devices is closely described by a power law, which may be related to the brittle destruction of materials. The hypothesis of scale similarity leads to the conclusion that the size distribution of particles formed as a result of a brittle destruction is described by a power law with the exponent -{alpha} that can range from -4 to -1. The model of brittle destruction is described in terms of the fractal geometry, and the distribution exponent is expressed via the fractal dimension of packing. Under additional assumptions, it is possible to refinemore » the {alpha} value and, vice versa, to determine the type of destruction using the measured size distribution of particles.« less

Comparison between initial Magnetized Liner Inertial Fusion experiments and integrated simulations

NASA Astrophysics Data System (ADS)

Sefkow, A. B.; Gomez, M. R.; Geissel, M.; Hahn, K. D.; Hansen, S. B.; Harding, E. C.; Peterson, K. J.; Slutz, S. A.; Koning, J. M.; Marinak, M. M.

2014-10-01

The Magnetized Liner Inertial Fusion (MagLIF) approach to ICF has obtained thermonuclear fusion yields using the Z facility. Integrated magnetohydrodynamic simulations provided the design for the first neutron-producing experiments using capabilities that presently exist, and the initial experiments measured stagnation radii rstag < 75 μm, temperatures around 3 keV, and isotropic neutron yields up to YnDD = 2 ×1012 from imploded liners reaching peak velocities around 70 km/s over an implosion time of about 60 ns. We present comparisons between the experimental observables and post-shot degraded integrated simulations. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the National Nuclear Security Administration under Contract DE-AC04-94AL85000.

Deuterium microbomb rocket propulsion

NASA Astrophysics Data System (ADS)

Winterberg, F.

2010-01-01

Large scale manned space flight within the solar system is still confronted with the solution of two problems: (1) A propulsion system to transport large payloads with short transit times between different planetary orbits. (2) A cost effective lifting of large payloads into earth orbit. For the solution of the first problem a deuterium fusion bomb propulsion system is proposed where a thermonuclear detonation wave is ignited in a small cylindrical assembly of deuterium with a gigavolt-multimegaampere proton beam, drawn from the magnetically insulated spacecraft acting in the ultrahigh vacuum of space as a gigavolt capacitor. For the solution of the second problem, the ignition is done by argon ion lasers driven by high explosives, with the lasers destroyed in the fusion explosion and becoming part of the exhaust.

A tandem mirror hybrid plume plasma propulsion facility

NASA Technical Reports Server (NTRS)

Yang, T. F.; Krueger, W. A.; Peng, S.; Urbahn, J.; Chang-Diaz, F. R.

1988-01-01

This paper discusses a novel concept in electrodeless plasma propulsion, in which the materials problems are ameliorated by an electrodeless magnetic confinement scheme borrowed from the tandem mirror approach to controlled thermonuclear fusion. The concept also features a two-stage magnetic nozzle with an annular hypersonic coaxial gas injector near the throat. The nozzle produces hybrid plume by the coaxial injection of hypersonic neutral gas, and the gas layer thus formed protects the material walls from the hot plasma and, through increased collisions, helps detach it from the diverging magnetic field. The tandem mirror plasma propulsion facility is capable of delivering a variable I(sp). The results of numerical simulation of this concept are presented together with those from an experimental tandem-mirror plasma propulsion device.

Three-dimensional analysis of tokamaks and stellarators

PubMed Central

Garabedian, Paul R.

2008-01-01

The NSTAB equilibrium and stability code and the TRAN Monte Carlo transport code furnish a simple but effective numerical simulation of essential features of present tokamak and stellarator experiments. When the mesh size is comparable to the island width, an accurate radial difference scheme in conservation form captures magnetic islands successfully despite a nested surface hypothesis imposed by the mathematics. Three-dimensional asymmetries in bifurcated numerical solutions of the axially symmetric tokamak problem are relevant to the observation of unstable neoclassical tearing modes and edge localized modes in experiments. Islands in compact stellarators with quasiaxial symmetry are easier to control, so these configurations will become good candidates for magnetic fusion if difficulties with safety and stability are encountered in the International Thermonuclear Experimental Reactor (ITER) project. PMID:18768807

Current situation: New enthusiasm. [Nuclear fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

For decades the costly field of controlled nuclear fusion has been rocked by ups and downs, promise and problems. In spite of the many setbacks, scientists and DOE officials are determined to push ahead. [open quotes]We are very confident that by some time after the first decade of the next century, we will have a clear demonstration [of the technology] to give us unlimited energy....We are very excited about it,[close quotes] Energy Secretary Watkins said last spring in proposing a $360 million fusion energy budget for fiscal 1993. This article cites recent hey developments in terms of technical accomplishments, fundingmore » decisions, policy decisions, and efforts to collaborate internationally on controlled nuclear fusion. The International Thermonuclear Experimental Reactor is discussed also.« less

Artificial radionuclides in the surface waters of the Baltic Sea and the North Sea in the fall of 1984

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kadzhene, G.I.; Kleiza, I.V.; Korotkov, V.P.

1987-10-01

The authors compare data from the literature with data taken in the fall of 1984 on the concentrations of cesium 137, strontium 90, cesium 144, and tritium in the waters of the Baltic and North seas. Sampling was conducted along the coastal regions as well as offshore and the consequent concentration and distribution profiles are mapped. They attempt to assess the weight of meteorological and water current as well as seasonal factors on the determined levels and also point to possible sources of the isotopes, including nuclear power plants situated along Baltic and North Sea shorelines and an atmospheric testmore » of a thermonuclear bomb carried out by China.« less

Accreting Millisecond Pulsars: Neutron Star Masses and Radii

NASA Technical Reports Server (NTRS)

Strohmayer, Tod

2004-01-01

High amplitude X-ray brightness oscillations during thermonuclear X-ray bursts were discovered with the Rossi X-ray Timing Explorer (RXTE) in early 1996. Spectral and timing evidence strongly supports the conclusion that these oscillations are caused by rotational modulation of the burst emission and that they reveal the spin frequency of neutron stars in low mass X-ray binaries. The recent discovery of X-ray burst oscillations from two accreting millisecond pulsars has confirmed this basic picture and provided a new route to measuring neutron star properties and constraining the dense matter equation of state. I will briefly summarize the current observational understanding of accreting millisecond pulsars, and describe recent attempts to determine the mass and radius of the neutron star in XTE J1814-338.

A real-time n/γ digital pulse shape discriminator based on FPGA.

PubMed

Li, Shiping; Xu, Xiufeng; Cao, Hongrui; Yuan, Guoliang; Yang, Qingwei; Yin, Zejie

2013-02-01

A FPGA-based real-time digital pulse shape discriminator has been employed to distinguish between neutrons (n) and gammas (γ) in the Neutron Flux Monitor (NFM) for International Thermonuclear Experimental Reactor (ITER). The discriminator takes advantages of the Field Programmable Gate Array (FPGA) parallel and pipeline process capabilities to carry out the real-time sifting of neutrons in n/γ mixed radiation fields, and uses the rise time and amplitude inspection techniques simultaneously as the discrimination algorithm to observe good n/γ separation. Some experimental results have been presented which show that this discriminator can realize the anticipated goals of NFM perfectly with its excellent discrimination quality and zero dead time. Copyright © 2012 Elsevier Ltd. All rights reserved.

Laser or charged-particle-beam fusion reactor with direct electric generation by magnetic flux compression

DOEpatents

Lasche, G.P.

1983-09-29

The invention is a laser or particle-beam-driven fusion reactor system which takes maximum advantage of both the very short pulsed nature of the energy release of inertial confinement fusion (ICF) and the very small volumes within which the thermonuclear burn takes place. The pulsed nature of ICF permits dynamic direct energy conversion schemes such as magnetohydrodynamic (MHD) generation and magnetic flux compression; the small volumes permit very compact blanket geometries. By fully exploiting these characteristics of ICF, it is possible to design a fusion reactor with exceptionally high power density, high net electric efficiency, and low neutron-induced radioactivity. The invention includes a compact blanket design and method and apparatus for obtaining energy utilizing the compact blanket.

NEUTRON SOURCE USING MAGNETIC COMPRESSION OF PLASMA

DOEpatents

Quinn, W.E.; Elmore, W.C.; Little, E.M.; Boyer, K.; Tuck, J.L.

1961-10-31

A fusion reactor is described that utilizes compression and heating of an ionized thermonuclear fuel by an externally applied magnetic field, thus avoiding reliance on the pinch effect and its associated instability problems. The device consists of a gas-confining ceramic container surrounded by a single circumferential coil having a shape such as to produce a magnetic mirror geometry. A sinusoidally-oscillating, exponentially-damped current is passed circumferentially around the container, through the coil, inducing a circumferential current in the gas. Maximum compression and plasma temperature are obtained at the peak of the current oscillations, coinciding with maximum magnetic field intensity. Enhanced temperatures are obtained in the second and succeeding half cycles because the thermal energy accumulates from one half cycle to the next. (AEC)

On a thermonuclear origin for the 1980-81 deep light minimum of the symbiotic nova PU Vul

NASA Technical Reports Server (NTRS)

Sion, Edward M.

1993-01-01

The puzzling 1980-81 deep light minimum of the symbiotic nova PU Vul is discussed in terms of a sequence of quasi-static evolutionary models of a hot, 0.5 solar mass white dwarf accreting H-rich matter at a rate 1 x 10 exp -8 solar mass/yr. On the basis of the morphological behavior of the models, it is suggested that the deep light minimum of PU Vul could have been the result of two successive, closely spaced, hydrogen shell flashes on an accreting white dwarf whose core thermal structure and accreted H-rich envelope was not in a long-term thermal 'cycle-averaged' steady state with the rate of accretion.

Ultraviolet observations of the symbiotic star AS 296

NASA Technical Reports Server (NTRS)

Gutierrez-Moreno, A.; Moreno, H.; Feibelman, W. A.

1992-01-01

AS 296 is a well-known S-type symbiotic star which underwent an optical outburst during 1988. In this paper, UV data based on IUE observations obtained both during the quiescent and outburst stages are presented and discussed, correlating them to observations made in the optical region. It is concluded that the object is a symbiotic nova, in which the outburst is due to a thermonuclear runaway produced in the hydrogen-burning shell of a white dwarf with M of about 0.5 solar masses, accreting from the late-type giant at a rate M(acc) of about 9.7 x 10 exp -9 solar mass/year. It is not possible to determine from the observations if the hydrogen flash is degenerate or nondegenerate.

Work of the Tamm-Sakharov group on the first hydrogen bomb

NASA Astrophysics Data System (ADS)

Ritus, V. I.

2014-09-01

This review is an extended version of a report delivered at a session of the Department of Physical Sciences, the Department of Energetics, Mechanical Engineering, Mechanics, and Control Processes, and the Coordination Council on Technical Sciences of the RAS devoted to the 60th anniversary of the first hydrogen bomb test. The significant physical ideas suggested by A D Sakharov and V L Ginzburg underlying our first hydrogen bomb, RDS-6s, and numerous concrete problems and difficulties that had to be solved and overcome in designing thermonuclear weapons are presented. The understanding of the country's leaders and the Atomic Project managers of the exceptional role of fundamental science in the appearance and implementation of our scientists' concrete ideas and suggestions is emphasized.

Characterization of high flux magnetized helium plasma in SCU-PSI linear device

NASA Astrophysics Data System (ADS)

Xiaochun, MA; Xiaogang, CAO; Lei, HAN; Zhiyan, ZHANG; Jianjun, WEI; Fujun, GOU

2018-02-01

A high-flux linear plasma device in Sichuan University plasma-surface interaction (SCU-PSI) based on a cascaded arc source has been established to simulate the interactions between helium and hydrogen plasma with the plasma-facing components in fusion reactors. In this paper, the helium plasma has been characterized by a double-pin Langmuir probe. The results show that the stable helium plasma beam with a diameter of 26 mm was constrained very well at a magnetic field strength of 0.3 T. The core density and ion flux of helium plasma have a strong dependence on the applied current, magnetic field strength and gas flow rate. It could reach an electron density of 1.2 × 1019 m-3 and helium ion flux of 3.2 × 1022 m-2 s-1, with a gas flow rate of 4 standard liter per minute, magnetic field strength of 0.2 T and input power of 11 kW. With the addition of -80 V applied to the target to increase the helium ion energy and the exposure time of 2 h, the flat top temperature reached about 530 °C. The different sizes of nanostructured fuzz on irradiated tungsten and molybdenum samples surfaces under the bombardment of helium ions were observed by scanning electron microscopy. These results measured in the SCU-PSI linear device provide a reference for International Thermonuclear Experimental Reactor related PSI research.

Constraining Calcium Production in Novae

NASA Astrophysics Data System (ADS)

Tiwari, Pranjal; C. Fry, C. Wrede Team; A. Chen, J. Liang Collaboration; S. Bishop, T. Faestermann, D. Seiler Collaboration; R. Hertenberger, H. Wirth Collaboration

2017-09-01

Calcium is an element that can be produced by thermonuclear reactions in the hottest classical novae. There are discrepancies between the abundance of Calcium observed in novae and expectations based on astrophysical models. Unbound states 1 MeV above the proton threshold affect the production of Calcium in nova models because they act as resonances in the 38 K(p , γ) 39 Ca reaction present. This work describes an experiment to measure the energies of the excited states of 39 Ca . We will bombard a thin target of 40 Ca with a beam of 22 MeV deuterons, resulting in tritons and 39Ca. We will use a Q3D magnetic spectrograph from the MLL in Garching, Germany to momenta analyze the tritons to observe the excitation energies of the resulting 39 Ca states. Simulations have been run to determine the optimal spectrograph settings. We decided to use a chemically stable target composed of CaF2 , doing so resulted in an extra contaminant, Fluorine, which is dealt with by measuring the background from a LiF target. These simulations have led to settings and targets that will result in the observation of the 39 Ca states of interest with minimal interference from contaminants. Preliminary results from this experiment will be presented. National Sciences and Engineering Research Council of Canada and U.S. National Science Foundation.

The progenitors of supernovae Type Ia

NASA Astrophysics Data System (ADS)

Toonen, Silvia

2014-09-01

Despite the significance of Type Ia supernovae (SNeIa) in many fields in astrophysics, SNeIa lack a theoretical explanation. SNeIa are generally thought to be thermonuclear explosions of carbon/oxygen (CO) white dwarfs (WDs). The canonical scenarios involve white dwarfs reaching the Chandrasekhar mass, either by accretion from a non-degenerate companion (single-degenerate channel, SD) or by a merger of two CO WDs (double-degenerate channel, DD). The study of SNeIa progenitors is a very active field of research for binary population synthesis (BPS) studies. The strength of the BPS approach is to study the effect of uncertainties in binary evolution on the macroscopic properties of a binary population, in order to constrain binary evolutionary processes. I will discuss the expected SNeIa rate from the BPS approach and the uncertainties in their progenitor evolution, and compare with current observations. I will also discuss the results of the POPCORN project in which four BPS codes were compared to better understand the differences in the predicted SNeIa rate of the SD channel. The goal of this project is to investigate whether differences in the simulated populations are due to numerical effects or whether they can be explained by differences in the input physics. I will show which assumptions in BPS codes affect the results most and hence should be studied in more detail.

Superconductivity and fusion energy—the inseparable companions

NASA Astrophysics Data System (ADS)

Bruzzone, Pierluigi

2015-02-01

Although superconductivity will never produce energy by itself, it plays an important role in energy-related applications both because of its saving potential (e.g., power transmission lines and generators), and its role as an enabling technology (e.g., for nuclear fusion energy). The superconducting magnet’s need for plasma confinement has been recognized since the early development of fusion devices. As long as the research and development of plasma burning was carried out on pulsed devices, the technology of superconducting fusion magnets was aimed at demonstrations of feasibility. In the latest generation of plasma devices, which are larger and have longer confinement times, the superconducting coils are a key enabling technology. The cost of a superconducting magnet system is a major portion of the overall cost of a fusion plant and deserves significant attention in the long-term planning of electricity supply; only cheap superconducting magnets will help fusion get to the energy market. In this paper, the technology challenges and design approaches for fusion magnets are briefly reviewed for past, present, and future projects, from the early superconducting tokamaks in the 1970s, to the current ITER (International Thermonuclear Experimental Reactor) and W7-X projects and future DEMO (Demonstration Reactor) projects. The associated cryogenic technology is also reviewed: 4.2 K helium baths, superfluid baths, forced-flow supercritical helium, and helium-free designs. Open issues and risk mitigation are discussed in terms of reliability, technology, and cost.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Libby, S B

Much has been written about Edward TEller, but little of it is objective. Given, on the one hand, his position as one of the most inventive theoretical physicists of the 20th century, and on the other, his central role in the development and advocacy of thermonuclear weapons, one might imagine it impossible at this point in history to write a scholarly, impartial account of Teller's life and his impact. Now, however, Istvan Hargittai, a prominent Hungarian physical chemist and historian of science, has written a balanced, thoughtful, and beautifully research biography that comes closest. Hargittai is uniquely qualified for thismore » difficult task. Coming a generation and a half later from a similar Hungarian-Jewish background, Hargittai understands well the influences and terrible events that shaped Teller. The advent of virulent, political anti-Semitism, first in Hungary and then in Germany, made Teller twice a refugee. Both Teller and Hargittai lost close family in the Holocaust; Hargittai was himself liberated from a Nazi concentration camp as a child. While Teller was in the US by then, his and Hargittai's surviving family members in Hungary suffered mistreatment at the hands of the postwar Hungarian Communist dictatorship. Hargittai's informed Eastern European perspective also provides a fresh viewpoint to the cold war context of the second half of Teller's career. Furthermore, Hargittai's own scientific work in molecular structure clearly makes him appreciate of Teller's breakthroughs in that field in the 1930s.« less

Resident research in internal medicine training programs.

PubMed

Alguire, P C; Anderson, W A; Albrecht, R R; Poland, G A

1996-02-01

To determine how well medical residency programs are prepared to meet the new Accreditation Council of Graduate Medical Education (ACGME) accreditation guidelines for resident scholarly activity. Cross-sectional study using a mailed survey. Program directors of all ACGME-accredited internal medicine residency programs. Program directors were asked to list the scholarly activities and products of their residents and their programs' minimal expectations for resident research; available academic, faculty, technical, and personnel support for resident research; perceived barriers to resident research; and the desired educational and skill outcomes of resident research. The responses of university-based training programs were compared with those of non-university-based programs. 271 program directors returned the survey, yielding a response rate of 65%. Ninety-seven percent of all programs have established scholarly guidelines consistent with accreditation requirements. Although only 37% of programs reported having an organized, comprehensive research curriculum, 70% taught skills important to research. Technical support and resources were generally available for resident research; the most frequently cited barrier to resident research was lack of resident time. University-based and non-university-based training programs differed in important ways. Generally, non-university-based programs had more research activity and structure, and they exceeded university-based programs in the number of oral and poster presentations given at local, state, and national professional meetings. Most programs have in place the basic elements conducive to resident research. Program directors have identified and teach educational outcomes and skills that are likely to have lifelong benefits for most of their graduates.

USAF Summer Research Program - 1993 Summer Research Extension Program Final Reports, Volume 2, Phillips Laboratory

DTIC Science & Technology

1994-11-01

Research Extension Program Phillips Laboratory Kirtland Air Force Base Sponsored by: Air Force Office of Scientific Research Boiling Air Force Base...Program Phillips Laboratory Sponsored by: Air Force Office of Scientific Research Bolling Air Force Base, Washington, D.C. and Arkansas Tech University...Summer Research Extension Program (SREP) Phillips

The development of a TED-Ed online resident research training program.

PubMed

Moreau, Katherine A; Pound, Catherine M; Peddle, Beth; Tokarewicz, Jaclyn; Eady, Kaylee

2014-01-01

Pediatric health research is important for improving the health and well-being of children and their families. To foster the development of physicians' research competencies, it is vital to integrate practical and context-specific research training into residency programs. To describe the development of a resident research training program at one tertiary care pediatric academic health sciences center in Ontario, Canada. We surveyed residents and pediatricians/research staff to establish the need and content for a resident research training program. Residents and resident research supervisors agreed or strongly agreed that research training is important for residents. However, few residents and supervisors believed that their academic health sciences center provided adequate training and resources to support resident research. As such, an online resident research training program was established. Residents and supervisors agreed that the program should focus on the following topics: 1) critically evaluating research literature, 2) writing a research proposal, 3) submitting an application for research funding, and 4) writing a manuscript. This highly accessible, context-specific, and inexpensive online program model may be of interest and benefit to other residency programs as a means to enhance residents' scholarly roles. A formal evaluation of the research training program is now underway.

Status of anesthesiology resident research education in the United States: structured education programs increase resident research productivity.

PubMed

Ahmad, Shireen; De Oliveira, Gildasio S; McCarthy, Robert J

2013-01-01

The enhancement of resident research education has been proposed to increase the number of academic anesthesiologists with the skills and knowledge to conduct meaningful research. Program directors (PDs) of the U.S. anesthesiology residency programs were surveyed to evaluate the status of research education during residency training and to test the hypothesis that structured programs result in greater resident research productivity based on resident publications. Survey responses were solicited from 131 anesthesiology residency PDs. Seventy-four percent of PDs responded to the survey. Questions evaluated department demographic information, the extent of faculty research activity, research resources and research funding in the department, the characteristics of resident research education and resident research productivity, departmental support for resident research, and perceived barriers to resident research education. Thirty-two percent of programs had a structured resident research education program. Structured programs were more likely to be curriculum based, require resident participation in a research project, and provide specific training in presentation and writing skills. Productivity expectations were similar between structured and nonstructured programs. Forty percent of structured programs had > 20% of trainees with a publication in the last 2 years compared with 14% of departments with unstructured programs (difference, 26%; 99% confidence interval [CI], 8%-51%; P = 0.01). The percentage of programs that had research rotations for ≥2 months was not different between the structured and the nonstructured programs. A research rotation of >2 months did not increase the percentage of residents who had published an article within the last 2 months compared with a research rotation of <2 months (difference, 13%; 99% CI, 10%-37%; P = 0.14). There was no difference in the percentage of faculty involved in research in structured compared with unstructured research education. In programs with <20% of faculty involved in research, 15% reported >20% of residents with a publication in the last 2 years compared with 36% in programs with >20% of faculty involvement (difference, 21%; 99% CI, -4% to 46%; P = 0.03). Our findings suggest that structured residency research programs are associated with higher resident research productivity. The program duration and the fraction of faculty in resident research education did not significantly increase research productivity. Research training is an integral component of resident education, but the mandatory enhancement of resident research education will require a significant change in the culture of academic anesthesiology leadership and faculty.

LTRC annual research program : fiscal year July 1, 2015 - June 30, 2016.

DOT National Transportation Integrated Search

2015-06-01

Contents: Budget Recap Sheets; Project Summary Sheets; FHWA Part II SPR Funded Research Program; FHWA LTAP Funded Program; FHWA STP Funded Technology Transfer & Education Program; State Funded Research Program; Self-Generated Funded Research; Other D...

History of the State Water Resources Research Institute Program

USGS Publications Warehouse

Burton, J.S.

1984-01-01

The State Water Resources Research Institute Program, established in 1964, consists of 54 Water Resources Research Institutes located at land-grant universities in each of the 50 states and Puerto Rico, the District of Columbia, Guam, and the Virgin Islands. The program evolved from the Water Resources Research Act of 1964, as amended, the Water Research and Development Act of 1978, Public Law 94-457, and the Water Research and Development Act of 1984. These laws authorize the following components of the Institute Program: (1) the annual allotment and matching grants program for the institutes and (2) the additional and saline water research programs for organizations in addition to the State Water Resources Research Institutes. This report summarizes the legislative history, budget history, research program development, and program accomplishments. The State Water Resources Research Program has been administered to by the Office of Water Resources Research (OWRR) (1964-1974), the Office of Water Research and Technology (OWRT) (1974-1982), the Office of Water Policy (OWP) (1982-1983) , and the U.S. Geological Survey (USGS) (1983-present). (USGS)

Real-Time Processing System for the JET Hard X-Ray and Gamma-Ray Profile Monitor Enhancement

NASA Astrophysics Data System (ADS)

Fernandes, Ana M.; Pereira, Rita C.; Neto, André; Valcárcel, Daniel F.; Alves, Diogo; Sousa, Jorge; Carvalho, Bernardo B.; Kiptily, Vasily; Syme, Brian; Blanchard, Patrick; Murari, Andrea; Correia, Carlos M. B. A.; Varandas, Carlos A. F.; Gonçalves, Bruno

2014-06-01

The Joint European Torus (JET) is currently undertaking an enhancement program which includes tests of relevant diagnostics with real-time processing capabilities for the International Thermonuclear Experimental Reactor (ITER). Accordingly, a new real-time processing system was developed and installed at JET for the gamma-ray and hard X-ray profile monitor diagnostic. The new system is connected to 19 CsI(Tl) photodiodes in order to obtain the line-integrated profiles of the gamma-ray and hard X-ray emissions. Moreover, it was designed to overcome the former data acquisition (DAQ) limitations while exploiting the required real-time features. The new DAQ hardware, based on the Advanced Telecommunication Computer Architecture (ATCA) standard, includes reconfigurable digitizer modules with embedded field-programmable gate array (FPGA) devices capable of acquiring and simultaneously processing data in real-time from the 19 detectors. A suitable algorithm was developed and implemented in the FPGAs, which are able to deliver the corresponding energy of the acquired pulses. The processed data is sent periodically, during the discharge, through the JET real-time network and stored in the JET scientific databases at the end of the pulse. The interface between the ATCA digitizers, the JET control and data acquisition system (CODAS), and the JET real-time network is provided by the Multithreaded Application Real-Time executor (MARTe). The work developed allowed attaining two of the major milestones required by next fusion devices: the ability to process and simultaneously supply high volume data rates in real-time.

Model based multivariable controller for large scale compression stations. Design and experimental validation on the LHC 18KW cryorefrigerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bonne, François; Bonnay, Patrick; Alamir, Mazen

2014-01-29

In this paper, a multivariable model-based non-linear controller for Warm Compression Stations (WCS) is proposed. The strategy is to replace all the PID loops controlling the WCS with an optimally designed model-based multivariable loop. This new strategy leads to high stability and fast disturbance rejection such as those induced by a turbine or a compressor stop, a key-aspect in the case of large scale cryogenic refrigeration. The proposed control scheme can be used to have precise control of every pressure in normal operation or to stabilize and control the cryoplant under high variation of thermal loads (such as a pulsedmore » heat load expected to take place in future fusion reactors such as those expected in the cryogenic cooling systems of the International Thermonuclear Experimental Reactor ITER or the Japan Torus-60 Super Advanced fusion experiment JT-60SA). The paper details how to set the WCS model up to synthesize the Linear Quadratic Optimal feedback gain and how to use it. After preliminary tuning at CEA-Grenoble on the 400W@1.8K helium test facility, the controller has been implemented on a Schneider PLC and fully tested first on the CERN's real-time simulator. Then, it was experimentally validated on a real CERN cryoplant. The efficiency of the solution is experimentally assessed using a reasonable operating scenario of start and stop of compressors and cryogenic turbines. This work is partially supported through the European Fusion Development Agreement (EFDA) Goal Oriented Training Program, task agreement WP10-GOT-GIRO.« less

Physical control oriented model of large scale refrigerators to synthesize advanced control schemes. Design, validation, and first control results

NASA Astrophysics Data System (ADS)

Bonne, François; Alamir, Mazen; Bonnay, Patrick

2014-01-01

In this paper, a physical method to obtain control-oriented dynamical models of large scale cryogenic refrigerators is proposed, in order to synthesize model-based advanced control schemes. These schemes aim to replace classical user experience designed approaches usually based on many independent PI controllers. This is particularly useful in the case where cryoplants are submitted to large pulsed thermal loads, expected to take place in the cryogenic cooling systems of future fusion reactors such as the International Thermonuclear Experimental Reactor (ITER) or the Japan Torus-60 Super Advanced Fusion Experiment (JT-60SA). Advanced control schemes lead to a better perturbation immunity and rejection, to offer a safer utilization of cryoplants. The paper gives details on how basic components used in the field of large scale helium refrigeration (especially those present on the 400W @1.8K helium test facility at CEA-Grenoble) are modeled and assembled to obtain the complete dynamic description of controllable subsystems of the refrigerator (controllable subsystems are namely the Joule-Thompson Cycle, the Brayton Cycle, the Liquid Nitrogen Precooling Unit and the Warm Compression Station). The complete 400W @1.8K (in the 400W @4.4K configuration) helium test facility model is then validated against experimental data and the optimal control of both the Joule-Thompson valve and the turbine valve is proposed, to stabilize the plant under highly variable thermals loads. This work is partially supported through the European Fusion Development Agreement (EFDA) Goal Oriented Training Program, task agreement WP10-GOT-GIRO.

Time-resolved record of 236U and 239,240Pu isotopes from a coral growing during the nuclear testing program at Enewetak Atoll (Marshall Islands).

PubMed

Froehlich, M B; Chan, W Y; Tims, S G; Fallon, S J; Fifield, L K

2016-12-01

A comprehensive series of nuclear tests were carried out by the United States at Enewetak Atoll in the Marshall Islands, especially between 1952 and 1958. A Porites Lutea coral that was growing in the Enewetak lagoon within a few km of all of the high-yield tests contains a continuous record of isotopes, which are of interest (e.g. 14 C, 236 U, 239,240 Pu) through the testing period. Prior to the present work, 14 C measurements at ∼2-month resolution had shown pronounced peaks in the Δ 14 C data that coincided with the times at which tests were conducted. Here we report measurements of 236 U and 239,240 Pu on the same coral using accelerator mass spectrometry, and again find prominent peaks in the concentrations of these isotopes that closely follow those in 14 C. Consistent with the 14 C data, the magnitudes of these peaks do not, however, correlate well with the explosive yields of the corresponding tests, indicating that smaller tests probably contributed disproportionately to the debris that fell in the lagoon. Additional information about the different tests can also be obtained from the 236 U/ 239 Pu and 240 Pu/ 239 Pu ratios, which are found to vary dramatically over the testing period. In particular, the first thermonuclear test, Ivy-Mike, has characteristic 236 U/ 239 Pu and 240 Pu/ 239 Pu signatures which are diagnostic of the first arrival of nuclear test material in various archives. Copyright © 2016 Elsevier Ltd. All rights reserved.