WorldWideScience

Sample records for spontaneous toroidal moment

  1. Toroidal Dipole Moment of a Massless Neutrino

    International Nuclear Information System (INIS)

    Cabral-Rosetti, L. G.; Mondragon, M.; Perez, E. Reyes

    2009-01-01

    We obtain the toroidal dipole moment of a massless neutrino τ v l M using the results for the anapole moment of a massless Dirac neutrino a v l D , which was obtained in the context of the Standard Model of the electroweak interactions (SM)SU(2) L x U(1) Y .

  2. Absence of toroidal moments in 'aromagnetic' anthracene

    Energy Technology Data Exchange (ETDEWEB)

    Alborghetti, S; Coey, J M D [School of Physics, Trinity College, Dublin 2 (Ireland); Puppin, E; Brenna, M; Pinotti, E; Zanni, P [Dipartimento di Fisica, Politecnico di Milano, Milano (Italy)], E-mail: alborgs@tcd.ie

    2008-06-15

    Colloidal suspensions of anthracene and other aromatic compounds have been shown to respond to a magnetic field as if they possessed a permanent magnetic moment. This phenomenon was named 'aromagnetism' by Spartakov and Tolstoi, and it was subsequently attributed to the interaction of an electric toroidal moment with a time-varying magnetic field. However, there has been no independent confirmation of the original work. Here, we have selected purified anthracene crystallites which respond to a low magnetic field and investigate how this response depends on the gradient and the time derivative of the field. We conclude that the anomaly cannot be attributed to a toroidal interaction but is due to a constant magnetic moment of the particles. Close examinations using magnetometry and scanning electron microscopy reveal metallic clusters of Fe and Ni up to a few hundred nanometres in size embedded in the anomalous crystallites. These inclusions represent 1.8 ppm by weight of the sample. The observed presence of ferromagnetic inclusions in the ppm range is sufficient to explain the anomalous magnetic properties of micron-sized anthracene crystals, including the reported optical properties of the colloidal suspensions.

  3. Toroidal Dipole Moment of the Lightest Neutralino in the MSSM

    International Nuclear Information System (INIS)

    Cabral-Rosetti, L G; Mondragon, M; Perez, E Reyes

    2011-01-01

    In order to characterize one of the most favored candidates for dark matter, we calculate the anapole form factor of the lightest neutralino in the Minimal Supersymmetric Standard Model (MSSM) at the one-loop level. As a Majorana fermion, this particle only shows one electromagnetic property, the toroidal dipole moment, which is directly related to the anapole form factor. We obtain the result analitically in terms of two- and three-points Passarino-Veltman scalar functions and evaluate it for a given spectrum of supersymmetric masses and matrix elements. This work is part of a broader project still in progress.

  4. Manifestation of the cyclo-toroid nuclear moment in anomalous conversion and Lamb shift

    OpenAIRE

    Tkalya, E. V.

    2005-01-01

    We offer the hypothesis that atomic nuclei, nucleons, and atoms possess a new type of electromagnetic moment, that we call a ``cyclo-toroid moment''. In nuclei, this moment arises when the toroid dipole (anapole) moments are arrayed in the form of a ring, or, equivalently, when the magnetic moments of the nucleons are arranged in the form of rings which, in turn, constitute the surface of a torus. We establish theoretically that the cyclo-toroid moment plays a role in the processes of the ato...

  5. Theory and applications of toroidal moments in electrodynamics: their emergence, characteristics, and technological relevance

    Science.gov (United States)

    Talebi, Nahid; Guo, Surong; van Aken, Peter A.

    2018-01-01

    Dipole selection rules underpin much of our understanding in characterization of matter and its interaction with external radiation. However, there are several examples where these selection rules simply break down, for which a more sophisticated knowledge of matter becomes necessary. An example, which is increasingly becoming more fascinating, is macroscopic toroidization (density of toroidal dipoles), which is a direct consequence of retardation. In fact, dissimilar to the classical family of electric and magnetic multipoles, which are outcomes of the Taylor expansion of the electromagnetic potentials and sources, toroidal dipoles are obtained by the decomposition of the moment tensors. This review aims to discuss the fundamental and practical aspects of the toroidal multipolar moments in electrodynamics, from its emergence in the expansion set and the electromagnetic field associated with it, the unique characteristics of their interaction with external radiations and other moments, to the recent attempts to realize pronounced toroidal resonances in smart configurations of meta-molecules. Toroidal moments not only exhibit unique features in theory but also have promising technologically relevant applications, such as data storage, electromagnetic-induced transparency, unique magnetic responses and dichroism.

  6. The toroidal moment in condensed-matter physics and its relation to the magnetoelectric effect

    NARCIS (Netherlands)

    Spaldin, Nicola A.; Fiebig, Manfred; Mostovoy, Maxim

    2008-01-01

    The concept of toroidal moments in condensed-matter physics and their long-range ordering in a so-called ferrotoroidic state is reviewed. We show that ferrotoroidicity as a form of primary ferroic order can be understood both from microscopic (multipole expansion) and macroscopic (symmetry-based

  7. Structure of the radial electric field and toroidal/poloidal flow in high temperature toroidal plasma

    International Nuclear Information System (INIS)

    Ida, Katsumi

    2001-01-01

    The structure of the radial electric field and toroidal/poloidal flow is discussed for the high temperature plasma in toroidal systems, tokamak and Heliotron type magnetic configurations. The spontaneous toroidal and poloidal flows are observed in the plasma with improved confinement. The radial electric field is mainly determined by the poloidal flow, because the contribution of toroidal flow to the radial electric field is small. The jump of radial electric field and poloidal flow are commonly observed near the plasma edge in the so-called high confinement mode (H-mode) plasmas in tokamaks and electron root plasma in stellarators including Heliotrons. In general the toroidal flow is driven by the momentum input from neutral beam injected toroidally. There is toroidal flow not driven by neutral beam in the plasma and it will be more significant in the plasma with large electric field. The direction of these spontaneous toroidal flows depends on the symmetry of magnetic field. The spontaneous toroidal flow driven by the ion temperature gradient is in the direction to increase the negative radial electric field in tokamak. The direction of spontaneous toroidal flow in Heliotron plasmas is opposite to that in tokamak plasma because of the helicity of symmetry of the magnetic field configuration. (author)

  8. New material equations for electromagnetism with toroid polarizations

    International Nuclear Information System (INIS)

    Dubovik, V.M.; Martsenyuk, M.A.; Saha, B.

    1999-09-01

    With regard to the toroid contributions, a modified system of equations of electrodynamics moving continuous media has been obtained. Alternative formalisms to introduce the toroid moment contributions in the equations of electromagnetism has been worked out. The two four-potential formalism has been developed. Lorentz transformation laws for the toroid polarizations has been given. Covariant form of equations of electrodynamics of continuous media with toroid polarizations has been written. (author)

  9. [Role of host in spontaneous recovery from viral hepatitis C: the body's condition at the moment of infection].

    Science.gov (United States)

    Isaguliants, M G; Ozeretskovskaia, N N; Znoĭko, O O; Tsyganova, E V

    2008-01-01

    The condition of the host at the moment of infection is that its immune competence largely determines the efficiency, kinetics, and profile (Thl/Th2) of a further specific immunity response and, accordingly, the outcome of penetration of hepatitis C virus (HCV) into the body and subsequent acute infection (if it occurs). The parameters determining immune competence may include age, traumatizing exposures (operations, burns, wounds, and fractures), immunosuppressive therapy, stresses, con-infections, and alcohol use. The highest rates of spontaneous convalescence from HCV infection are observed in children and adolescents. Other human conditions are much shorter, transient; their impact is difficult to determine in the retrospective review and therefore it has not been adequately studied. Previous operations, posttransplantation immune suppression, immune modulation after blood transfusion, alcohol-induced immune imbalance, drug and narcotic intoxication are poor predictors. Immunosuppression and immune imbalance caused by viral and parasitic infections are observed among the host's temporary conditions affecting the outcome of HCV infection. The authors have analyzed the sequels of superinfections in patients with chronic hepatitis C, other hepatotropic viruses and the common liver fluke Schistosoma mansoni. The interesting therapeutic activities against HCV and parasitic infection (contamination with Echinococcus granulosus in particular), which are shown in the treatment of co-infection patients with alpha-interferon preparations that ensure normalization of immune deficiency caused by each of the infections and their increased combination. A deeper insight into the correlation between the condition of the host and its ability to eliminate the virus may be one more step on the road to the prevention of the infection and to the designing an effective vaccine against HCV.

  10. Toroid magnet test facility

    CERN Multimedia

    2002-01-01

    Because of its exceptional size, it was not feasible to assemble and test the Barrel Toroid - made of eight coils - as an integrated toroid on the surface, prior to its final installation underground in LHC interaction point 1. It was therefore decided to test these eight coils individually in a dedicated test facility.

  11. Toroidal helical fields

    International Nuclear Information System (INIS)

    Kucinski, M.Y.; Caldas, I.L.

    1986-08-01

    Using the conventional toroidal coordinate system Laplace's equation for the magnetic scalar potential due to toroidal helical currents is solved. The potential is written as a sum of an infinite series of functions. Each partial sum represents the potential within some accuracy. The effect of the winding law is analysed in the case of small curvature. (Author) [pt

  12. New Toroid shielding design

    CERN Multimedia

    Hedberg V

    On the 15th of June 2001 the EB approved a new conceptual design for the toroid shield. In the old design, shown in the left part of the figure above, the moderator part of the shielding (JTV) was situated both in the warm and cold areas of the forward toroid. It consisted both of rings of polyethylene and hundreds of blocks of polyethylene (or an epoxy resin) inside the toroid vacuum vessel. In the new design, shown to the right in the figure above, only the rings remain inside the toroid. To compensate for the loss of moderator in the toroid, the copper plug (JTT) has been reduced in radius so that a layer of borated polyethylene can be placed around it (see figure below). The new design gives significant cost-savings and is easier to produce in the tight time schedule of the forward toroid. Since the amount of copper is reduced the weight that has to be carried by the toroid is also reduced. Outgassing into the toroid vacuum was a potential problem in the old design and this is now avoided. The main ...

  13. Samus Toroid Installation Fixture

    Energy Technology Data Exchange (ETDEWEB)

    Stredde, H.; /Fermilab

    1990-06-27

    The SAMUS (Small Angle Muon System) toroids have been designed and fabricated in the USSR and delivered to D0 ready for installation into the D0 detector. These toroids will be installed into the aperture of the EF's (End Toroids). The aperture in the EF's is 72-inch vertically and 66-inch horizontally. The Samus toroid is 70-inch vertically by 64-inch horizontally by 66-inch long and weighs approximately 38 tons. The Samus toroid has a 20-inch by 20-inch aperture in the center and it is through this aperture that the lift fixture must fit. The toroid must be 'threaded' through the EF aperture. Further, the Samus toroid coils are wound about the vertical portion of the aperture and thus limit the area where a lift fixture can make contact and not damage the coils. The fixture is designed to lift along a surface adjacent to the coils, but with clearance to the coil and with contact to the upper steel block of the toroid. The lift and installation will be done with the 50 ton crane at DO. The fixture was tested by lifting the Samus Toroid 2-inch off the floor and holding the weight for 10 minutes. Deflection was as predicted by the design calculations. Enclosed are sketches of the fixture and it relation to both Toroids (Samus and EF), along with hand calculations and an Finite Element Analysis. The PEA work was done by Kay Weber of the Accelerator Engineering Department.

  14. Quantum electron transport in toroidal carbon nanotubes

    Science.gov (United States)

    Jack, Mark; Encinosa, Mario

    2008-03-01

    Electron transport under bias is treated in tight-binding approximation using a non-equilibrium Green's function approach. Density-of-states D(E), transmissivity T(E), and current ISD are calculated through a (3,3) armchair nanotorus with laterally attached metallic leads and a magnetic field penetrating the toroidal plane. Plateaus in T(E) through the torus are observed as a function of both the relative angle between leads and magnetic flux. Initial computational studies performed with 1800 atoms and attached leads show substantial computational slowdown when increasing the system size by a factor of two. Results are generated by inverting the device Hamiltonian with a standard recursion method extended to account for unit cell toroidal closure. Significant computational speed-up is expected for a parallelized code on a multiprocessor computer cluster. The dependence of electronic features on torus size and torus curvature is tested for three tori with 900, 1800 and 3600 carbon atoms, respectively. References: 1. M. Jack and M. Encinosa, Quantum electron transport in toroidal carbon nanotubes with metallic leads. ArXiv: quant-ph/0709.0760. 2. M. Encinosa and M. Jack, Dipole and solenoidal magnetic moments of electronic surface currents on toroidal nanostructures. J. Comp.-Aided Mat. Design (Springer), 14 (1) (2007) 65 -- 71.

  15. Toroidal nuclear fusion device

    International Nuclear Information System (INIS)

    Ito, Yutaka; Kasahara, Tatsuo; Takizawa, Teruhiro.

    1975-01-01

    Object: To design a device so as to be formed into a large-size and to arrange ports, through which neutral particles enter, in inclined fashion. Structure: Toroidal coils are wound about vacuum vessels which are divided into plural number. In the outer periphery of the vacuum vessels, ports are disposed inclined in the peripheral direction of the vacuum vessels and communicated with the vacuum vessels, and wall surfaces opposed to the ports of the toroidal coils adjacent at least the inclined sides of the ports are inclined substantially simularly to the port wall surfaces. (Kamimura, M.)

  16. Toroidal drift magnetic pumping

    International Nuclear Information System (INIS)

    Canobbio, E.

    1977-01-01

    A set of azimuthal coils which carry properly dephased rf-currents in the KHz frequency range can be used to heat toroidal plasmas by perpendicular Landau damping of subsonic Alfven waves. The heating mechanism and the rf-field structure are discussed in some detail

  17. Toroidal high-spin isomers in the nucleus 304120

    Science.gov (United States)

    Staszczak, A.; Wong, Cheuk-Yin; Kosior, A.

    2017-05-01

    Background: Strongly deformed oblate superheavy nuclei form an intriguing region where the toroidal nuclear structures may bifurcate from the oblate spheroidal shape. The bifurcation may be facilitated when the nucleus is endowed with a large angular moment about the symmetry axis with I =Iz . The toroidal high-K isomeric states at their local energy minima can be theoretically predicted using the cranked self-consistent Skyrme-Hartree-Fock method. Purpose: We use the cranked Skyrme-Hartree-Fock method to predict the properties of the toroidal high-spin isomers in the superheavy nucleus 120304184. Method: Our method consists of three steps: First, we use the deformation-constrained Skyrme-Hartree-Fock-Bogoliubov approach to search for the nuclear density distributions with toroidal shapes. Next, using these toroidal distributions as starting configurations, we apply an additional cranking constraint of a large angular momentum I =Iz about the symmetry z axis and search for the energy minima of the system as a function of the deformation. In the last step, if a local energy minimum with I =Iz is found, we perform at this point the cranked symmetry- and deformation-unconstrained Skyrme-Hartree-Fock calculations to locate a stable toroidal high-spin isomeric state in free convergence. Results: We have theoretically located two toroidal high-spin isomeric states of 120304184 with an angular momentum I =Iz=81 ℏ (proton 2p-2h, neutron 4p-4h excitation) and I =Iz=208 ℏ (proton 5p-5h, neutron 8p-8h) at the quadrupole moment deformations Q20=-297.7 b and Q20=-300.8 b with energies 79.2 and 101.6 MeV above the spherical ground state, respectively. The nuclear density distributions of the toroidal high-spin isomers 120304184(Iz=81 ℏ and 208 ℏ ) have the maximum density close to the nuclear matter density, 0.16 fm-3, and a torus major to minor radius aspect ratio R /d =3.25 . Conclusions: We demonstrate that aligned angular momenta of Iz=81 ℏ and 208 ℏ arising from

  18. Tokamak with liquid metal toroidal field coil

    International Nuclear Information System (INIS)

    Ohkawa, T.; Schaffer, M.J.

    1981-01-01

    Tokamak apparatus includes a pressure vessel for defining a reservoir and confining liquid therein. A toroidal liner disposed within the pressure vessel defines a toroidal space within the liner. Liquid metal fills the reservoir outside said liner. Electric current is passed through the liquid metal over a conductive path linking the toroidal space to produce a toroidal magnetic field within the toroidal space about the major axis thereof. Toroidal plasma is developed within the toroidal space about the major axis thereof

  19. Anomalous transport in toroidal plasmas

    International Nuclear Information System (INIS)

    Punjabi, A.

    1989-12-01

    When the magnetic moment of particle is conserved, there are three mechanisms which cause anomalous transport. These are: variation of magnetic field strength in flux surface, variation of electrostatic potential in flux surface, and destruction of flux surface. The anomalous transport of different groups of particles resulting from each of these mechanisms is different. This fact can be exploited to determine the cause of transport operative in an experimental situation. This approach can give far more information on the transport than the standard confinement time measurements. To implement this approach, we have developed Monte Carlo codes for toroidal geometries. The equations of motion are developed in a set of non-canonical, practical Boozer co-ordinates by means of Jacobian transformations of the particle drift Hamiltonian equations of motion. Effects of collisions are included by appropriate stochastic changes in the constants of motion. Effects of the loop voltage on particle motions are also included. We plan to apply our method to study two problems: the problem of the hot electron tail observed in edge region of ZT-40, and the energy confinement time in TOKAPOLE II. For the ZT-40 problem three situations will be considered: a single mode in the core, a stochastic region that covers half the minor radius, a stochastic region that covers the entire plasma. A turbulent spectrum of perturbations based on the experimental data of TOKAPOLE II will be developed. This will be used to simulate electron transport resulting from ideal instabilities and resistive instabilities in TOKAPOLE II

  20. Toroidal rotation studies in KSTAR

    Science.gov (United States)

    Lee, S. G.; Lee, H. H.; Yoo, J. W.; Kim, Y. S.; Ko, W. H.; Terzolo, L.; Bitter, M.; Hill, K.; KSTAR Team

    2014-10-01

    Investigation of the toroidal rotation is one of the most important topics for the magnetically confined fusion plasma researches since it is essential for the stabilization of resistive wall modes and its shear plays an important role to improve plasma confinement by suppressing turbulent transport. The most advantage of KSTAR tokamak for toroidal rotation studies is that it equips two main diagnostics including the high-resolution X-ray imaging crystal spectrometer (XICS) and charge exchange spectroscopy (CES). Simultaneous core toroidal rotation and ion temperature measurements of different impurity species from the XICS and CES have shown in reasonable agreement with various plasma discharges in KSTAR. It has been observed that the toroidal rotation in KSTAR is faster than that of other tokamak devices with similar machine size and momentum input. This may due to an intrinsically low toroidal field ripple and error field of the KSTAR device. A strong braking of the toroidal rotation by the n = 1 non-resonant magnetic perturbations (NRMPs) also indicates these low toroidal field ripple and error field. Recently, it has been found that n = 2 NRMPs can also damp the toroidal rotation in KSTAR. The detail toroidal rotation studies will be presented. Work supported by the Korea Ministry of Science, ICT and Future Planning under the KSTAR project.

  1. Toroidal simulation magnet tests

    International Nuclear Information System (INIS)

    Walstrom, P.L.; Domm, T.C.

    1975-01-01

    A number of different schemes for testing superconducting coils in a simulated tokamak environment are analyzed for their merits relative to a set of test criteria. Two of the concepts are examined in more detail: the so-called cluster test scheme, which employs two large background field coils, one on either side of the test coil, and the compact torus, a low-aspect ratio toroidal array of a small number of coils in which all of the coils are essentially test coils. Simulation of the pulsed fields of the tokamak is discussed briefly

  2. Fixed boundary toroidal plasma equilibria with toroidal flows

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Yanqiang [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Center for Magnetic Fusion Theory, Chinese Academy of Sciences, Hefei 230031 (China); Hu, Yemin; Xiang, Nong [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Center for Magnetic Fusion Theory, Chinese Academy of Sciences, Hefei 230031 (China)

    2016-04-15

    The fixed boundary toroidal plasma equilibria with toroidal flows are investigated by solving the modified Grad-Shafranov equation numerically in the cylindrical coordinate system. For normal equilibrium configurations with geometry and profiles similar to usual tokamaks with no flow, it is found that the effect of flow is to lead to an outward shift of the magnetic flux surfaces, together with the profiles of pressure, and mass and current densities. The shifts could become significant when the toroidal flow Mach number exceeds 0.5. For non-conventional current profiles, even for the usual tokamak geometry, novel current reversal equilibrium configurations may result, sometimes with changed topology in the poloidal flux function. This change in the topology of plasma equilibrium can be attributed to the large toroidal flow. The computed results may correspond to situations of intense tangential injection during the low toroidal current phase in expected experimental situations.

  3. Quantum mechanics of toroidal anions

    International Nuclear Information System (INIS)

    Afanas'ev, G.N.

    1990-01-01

    We consider a toroidal solenoid with an electric charge attached to it. It turns out that statistical properties of the wave function describing interacting toroidal anions depend on both their relative position and orientation. The influence of the particular gauge choice on the exchange properties of the wave function is studied. 30 refs.; 6 figs

  4. Device for supporting a toroidal coil in a toroidal type nuclear fusion device

    International Nuclear Information System (INIS)

    Kitazawa, Hakaru; Sato, Hiroshi.

    1975-01-01

    Object: To easily manufacture a center block having a strength sufficient to withstand an electromagnetic force exerted on the center of toroidal of a toroidal coil and to increase its reliability. Structure: In a device for supporting toroidal coils wherein the electromagnetic force exerted on the center of toroidal of a plurality of toroidal coils arranged in toroidal fashion, the contact surface between the toroidal coil and the center block is arranged parallel to the center axis of toroidal so as to receive the electromagnetic force exerted on the center of toroidal of the toroidal coil as the component of force in a radial direction. (Taniai, N.)

  5. Nuclear moments

    CERN Document Server

    Kopferman, H; Massey, H S W

    1958-01-01

    Nuclear Moments focuses on the processes, methodologies, reactions, and transformations of molecules and atoms, including magnetic resonance and nuclear moments. The book first offers information on nuclear moments in free atoms and molecules, including theoretical foundations of hyperfine structure, isotope shift, spectra of diatomic molecules, and vector model of molecules. The manuscript then takes a look at nuclear moments in liquids and crystals. Discussions focus on nuclear paramagnetic and magnetic resonance and nuclear quadrupole resonance. The text discusses nuclear moments and nucl

  6. Saddle-splay screening and chiral symmetry breaking in toroidal nematics

    OpenAIRE

    Koning, Vinzenz; van Zuiden, Benjamin C.; Kamien, Randall D.; Vitelli, Vincenzo

    2013-01-01

    We present a theoretical study of director fields in toroidal geometries with degenerate planar boundary conditions. We find spontaneous chirality: despite the achiral nature of nematics the director configuration show a handedness if the toroid is thick enough. In the chiral state the director field displays a double twist, whereas in the achiral state there is only bend deformation. The critical thickness increases as the difference between the twist and saddle-splay moduli grows. A positiv...

  7. Equivelar toroids with few flag-orbits

    OpenAIRE

    Collins, José; Montero, Antonio

    2018-01-01

    An $(n+1)$-toroid is a quotient of a tessellation of the $n$-dimensional Euclidean space with a lattice group. Toroids are generalizations of maps in the torus on higher dimensions and also provide examples of abstract polytopes. Equivelar toroids are those that are induced by regular tessellations. In this paper we present a classification of equivelar $(n+1)$-toroids with at most $n$ flag-orbits; in particular, we discuss a classification of $2$-orbit toroids of arbitrary dimension.

  8. Next generation toroidal devices

    International Nuclear Information System (INIS)

    Yoshikawa, Shoichi

    1998-10-01

    A general survey of the possible approach for the next generation toroidal devices was made. Either surprisingly or obviously (depending on one's view), the technical constraints along with the scientific considerations lead to a fairly limited set of systems for the most favorable approach for the next generation devices. Specifically if the magnetic field strength of 5 T or above is to be created by superconducting coils, it imposes minimum in the aspect ratio for the tokamak which is slightly higher than contemplated now for ITER design. The similar technical constraints make the minimum linear size of a stellarator large. Scientifically, it is indicated that a tokamak of 1.5 times in the linear dimension should be able to produce economically, especially if a hybrid reactor is allowed. For the next stellarator, it is strongly suggested that some kind of helical axis is necessary both for the (almost) absolute confinement of high energy particles and high stability and equilibrium beta limits. The author still favors a heliac most. Although it may not have been clearly stated in the main text, the stability afforded by the shearless layer may be exploited fully in a stellarator. (author)

  9. Private Moments

    OpenAIRE

    Paul R. Reed; Carol J. Cumber

    2000-01-01

    In October, 1996 Private Moments, an adult novelty store, opened for business in Huntsville, Texas. Huntsville had no ordinances in place to prevent the opening of this type of business. In fact, the local Small Business Development Center provided guidance and assistance to Edward Delagarza, the founder and owner of Private Moments. Many of the Huntsville citizens, unhappy with the opening of Private Moments, approached the City Council requesting that it be closed immediately and asked for ...

  10. Toroidal helical quartz forming machine

    International Nuclear Information System (INIS)

    Hanks, K.W.; Cole, T.R.

    1977-01-01

    The Scyllac fusion experimental machine used 10 cm diameter smooth bore discharge tubes formed into a simple toroidal shape prior to 1974. At about that time, it was discovered that a discharge tube was required to follow the convoluted shape of the load coil. A machine was designed and built to form a fused quartz tube with a toroidal shape. The machine will accommodate quartz tubes from 5 cm to 20 cm diameter forming it into a 4 m toroidal radius with a 1 to 5 cm helical displacement. The machine will also generate a helical shape on a linear tube. Two sets of tubes with different helical radii and wavelengths have been successfully fabricated. The problems encountered with the design and fabrication of this machine are discussed

  11. Toroidal Trivelpiece-Gould modes

    International Nuclear Information System (INIS)

    Stoessel, F.P.

    1979-01-01

    Electron plasma waves are treated in quasi-electrostatic approximation in a toroidal cavity of rectangular cross-section in an infinitely strong azimuthal magnetic field. The differential equation for the electrostatic potential, derived from fluid equations, can be separated using cylindrical coordinates. The eigenvalue problem for the radial dependence is solved numerically by a shooting method. Eigenvalues are given for different aspect ratios. Comparison with appropriate modes of the straight geometry shows that the toroidal frequencies generally lie some percent above those for the straight case. Plots of the eigenfunctions demonstrate clearly the influence of toroidicity. The deviation from symmetry (which should appear for straight geometry) depends not only on the aspect ratio but also strongly on the mode numbers. (author)

  12. The complex and unique ATLAS Toroid family

    CERN Multimedia

    2002-01-01

    Big parts for the toroid magnets that will be used in the ATLAS experiment have been continuously arriving at CERN since March. These structures will create the largest superconducting toroid magnet ever.

  13. Lowering the first ATLAS toroid

    CERN Document Server

    Maximilien Brice

    2004-01-01

    The ATLAS detector on the LHC at CERN will consist of eight toroid magnets, the first of which was lowered into the cavern in these images on 26 October 2004. The coils are supported on platforms where they will be attached to form a giant torus. The platforms will hold about 300 tonnes of ATLAS' muon chambers and will envelop the inner detectors.

  14. RF breakdown by toroidal helicons

    Indian Academy of Sciences (India)

    Abstract. Bounded whistlers are well-known for their efficient plasma production capabilities in thin cylindrical tubes. In this paper we shall present their radio frequency (RF) breakdown and discharge sustaining capabilities in toroidal systems. Pulsed RF power in the electronmagnetohy- drodynamic (EMHD) frequency ...

  15. RF breakdown by toroidal helicons

    Indian Academy of Sciences (India)

    Bounded whistlers are well-known for their efficient plasma production capabilities in thin cylindrical tubes. In this paper we shall present their radio frequency (RF) breakdown and discharge sustaining capabilities in toroidal systems. Pulsed RF power in the electronmagnetohydrodynamic (EMHD) frequency regime is fed to ...

  16. Onsager relaxation of toroidal plasmas

    International Nuclear Information System (INIS)

    Samain, A.; Nguyen, F.

    1997-01-01

    The slow relaxation of isolated toroidal plasmas towards their thermodynamical equilibrium is studied in an Onsager framework based on the entropy metric. The basic tool is a variational principle, equivalent to the kinetic equation, involving the profiles of density, temperature, electric potential, electric current. New minimization procedures are proposed to obtain entropy and entropy production rate functionals. (author)

  17. Collapse analysis of toroidal shell

    International Nuclear Information System (INIS)

    Pomares, R.J.

    1990-01-01

    This paper describes a study performed to determine the collapse characteristics of a toroidal shell using finite element method (FEM) analysis. The study also included free drop testing of a quarter scale prototype to verify the analytical results. The full sized toroidal shell has a 24-inch toroidal diameter with a 24-inch tubal diameter. The shell material is type 304 strainless steel. The toroidal shell is part of the GE Model 2000 transportation packaging, and acts as an energy absorbing device. The analyses performed were on a full sized and quarter scaled models. The finite element program used in all analyses was the LIBRA code. The analytical procedure used both the elasto-plastic and large displacement options within the code. The loading applied in the analyses corresponded to an impact of an infinite rigid plane oriented normal to the drop direction vector. The application of the loading continued incrementally until the work performed by the deforming structure equalled the kinetic energy developed in the free fall. The comparison of analysis and test results showed a good correlation

  18. Hybrid winding concept for toroids

    DEFF Research Database (Denmark)

    Schneider, Henrik; Andersen, Thomas; Knott, Arnold

    2013-01-01

    and placement machinery. This opens up the possibility for both an automated manufacturing process and an automated production process of toroidal magnetics such as power inductors, filtering inductors, air core inductors, transformers etc. Both the proposed hybrid and the common wire wound winding...

  19. Classification of symmetric toroidal orbifolds

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Maximilian; Ratz, Michael; Torrado, Jesus [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Vaudrevange, Patrick K.S. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2012-09-15

    We provide a complete classification of six-dimensional symmetric toroidal orbifolds which yield N{>=}1 supersymmetry in 4D for the heterotic string. Our strategy is based on a classification of crystallographic space groups in six dimensions. We find in total 520 inequivalent toroidal orbifolds, 162 of them with Abelian point groups such as Z{sub 3}, Z{sub 4}, Z{sub 6}-I etc. and 358 with non-Abelian point groups such as S{sub 3}, D{sub 4}, A{sub 4} etc. We also briefly explore the properties of some orbifolds with Abelian point groups and N=1, i.e. specify the Hodge numbers and comment on the possible mechanisms (local or non-local) of gauge symmetry breaking.

  20. Experimental studies of compact toroids

    International Nuclear Information System (INIS)

    1991-01-01

    The Berkeley Compact Toroid Experiment (BCTX) device is a plasma device with a Marshall-gun generated, low aspect ratio toroidal plasma. The device is capable of producing spheromak-type discharges and may, with some modification, produce low-aspect ratio tokamak configurations. A unique aspect of this experimenal devie is its large lower hybrid (LH) heating system, which consists of two 450MHz klystron tubes generating 20 megawatts each into a brambilla-type launching structure. Successful operation with one klystron at virtually full power (18 MW) has been accomplished with 110 μs pulse length. A second klystron is currently installed in its socket and magnet but has not been added to the RF drive system. This report describes current activities and accomplishments and describes the anticipated results of next year's activity

  1. Transporting the first ATLAS toroid

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    The first coil for the ATLAS toroid magnet is transported from its assembly hall at the CERN Meyrin site to the storage hall above the ATLAS cavern. This involves driving the massive transportation vehicle first through the Meyrin site and then across a main road only metres from the France-Swiss border. Eight magnets in total will be transported in this way before being lowered into the experimental cavern where they will be mounted in a huge ring surrounding the detector.

  2. Heating of toroidal plasmas by neutral injection

    International Nuclear Information System (INIS)

    Stix, T.H.

    1971-08-01

    This paper presents a brief review of the physics of ion acceleration, charge exchange and ionization, trajectories for fast ions in toroidal magnetic fields, and fast-ion thermalization. The injection of fast atoms is found to be a highly competitive method both for heating present-day experimental toroidal plasmas and for bringing full-scale toroidal CTR plasmas to low-density ignition. 13 refs., 9 figs

  3. Teachable Moment: Google Earth Takes Us There

    Science.gov (United States)

    Williams, Ann; Davinroy, Thomas C.

    2015-01-01

    In the current educational climate, where clearly articulated learning objectives are required, it is clear that the spontaneous teachable moment still has its place. Authors Ann Williams and Thomas Davinroy think that instructors from almost any discipline can employ Google Earth as a tool to take advantage of teachable moments through the…

  4. Up-down symmetry of the turbulent transport of toroidal angular momentum in tokamaks

    International Nuclear Information System (INIS)

    Parra, Felix I.; Barnes, Michael; Peeters, Arthur G.

    2011-01-01

    Two symmetries of the local nonlinear δf gyrokinetic system of equations in tokamaks in the high flow regime are presented. The turbulent transport of toroidal angular momentum changes sign under an up-down reflection of the tokamak and a sign change of both the rotation and the rotation shear. Thus, the turbulent transport of toroidal angular momentum must vanish for up-down symmetric tokamaks in the absence of both rotation and rotation shear. This has important implications for the modeling of spontaneous rotation.

  5. Fast Dump of the ATLAS Toroids

    CERN Document Server

    Dudarev, A; Volpini, Giovanni; Dudarev, Alexey; Kate, Herman Ten

    2010-01-01

    The toroidal magnet system of the ATLAS Detector at CERN consists of a Barrel Toroid (BT) and two End Cap Toroids (ECT-A and ECT-C). Each toroid is built up from eight racetrack coils wound with an aluminum stabilized NbTi conductor and indirectly cooled by forced flow liquid helium. The three toroids operate in series at 20.5 kA with a total stored energy of 1.5 GJ. In order to verify the reliability and effectiveness of the quench protection system, series of fast dump tests have been performed first of the single toroids and finally of the entire toroidal magnet system. In this paper a model to simulate the fast dump of the ATLAS toroids in single mode operation and in full system configuration is presented. The model is validated through comparison with measured data extracted from the ramp-and-quench runs. The calculated energy dissipation in the various coils is in very good agreement (within 1-2\\%) with the enthalpy changes estimated from the temperature measurements of the different parts of the cold ...

  6. Electrostatics of a Family of Conducting Toroids

    Science.gov (United States)

    Lekner, John

    2009-01-01

    An exact solution is found for the electrostatic potential of a family of conducting charged toroids. The toroids are characterized by two lengths "a" and "b", with "a" greater than or equal to "2b". They are closed, with no hole in the "doughnut". The results are obtained by considering the potential of two equal charges, displaced from the…

  7. Collaborative Moments

    DEFF Research Database (Denmark)

    Hastrup, Kirsten Blinkenberg

    2017-01-01

    as an experiment in real time, where insights gained intersubjectively gradually shape up as knowledge through analysis. This line of thought is brought to bear on a discussion of collaboration between anthropologists, archaeologists, and biologists in North West Greenland. Through actual experiences from...... the field, this article shows how knowledge generated on the edge of one’s familiar disciplinary territory may both expand and intensify the anthropological field. Collaborative moments are seen to make new anthropological insights emerge through the co-presence of several analytical perspectives...

  8. Toroidal effects on drift wave turbulence

    Energy Technology Data Exchange (ETDEWEB)

    LeBrun, M.J.; Tajima, T.; Gray, M.G.; Furnish, G.; Horton, W.

    1992-09-23

    The universal drift instability and other drift instabilities driven by density and temperature gradients in a toroidal system are investigated in both linear and nonlinear regimes via particle simulation. Runs in toroidal and cylindrical geometry show dramatic differences in plasma behavior, primarily due to the toroidicity-induced coupling of rational surfaces through the poloidal mode number m. In the toroidal system studied, the eigenmodes are seen to possess (i) an elongated, nearly global radial extent (ii) a higher growth rate than in the corresponding cylindrical system, (iii) an eigenfrequency nearly constant with radius, (iv) a global temperature relaxation and enhancement of thermal heat conduction. Most importantly, the measured Xi shows an increase with radius and an absolute value on the order of that observed in experiment. On the basis of our observations, we argue that the increase in Xi with radius observed in experiment is caused by the global nature of heat convection in the presence of toroidicity-induced mode coupling.

  9. Development of Toroidal Core Transformers

    Energy Technology Data Exchange (ETDEWEB)

    de Leon, Francisco [New York Univ. (NYU), Brooklyn, NY (United States). Dept. of Electrical and Computer Engineering

    2014-08-01

    The original objective of this project was to design, build and test a few prototypes of single-phase dry-type distribution transformers of 25 kVA, 2.4 kV primary to 120 V transformers using cores made of a continuous steel strip shaped like a doughnut (toroid). At different points during the development of the project, the scope was enhanced to include the more practical case of a 25 kVA transformer for a 13.8 kV primary system voltage. Later, the scope was further expanded to design and build a 50 kVA unit to transformer voltage from 7.62 kV to 2x120 V. This is a common transformer used by Con Edison of New York and they are willing to test it in the field. The project officially started in September 2009 and ended in May 2014. The progress was reported periodically to DOE in eighteen quarterly reports. A Continuation Application was submitted to DOE in June 2010. In May 2011 we have requested a non-cost extension of the project. In December 2011, the Statement of Project Objectives (SOPO) was updated to reflect the real conditions and situation of the project as of 2011. A second Continuation Application was made and funding was approved in 2013 by DOE and the end date was extended to May 2014. The technical challenges that were overcome in this project include: the development of the technology to pass the impulse tests, derive a model for the thermal performance, produce a sound mechanical design, and estimate the inrush current. However, the greatest challenge that we faced during the development of the project was the complications of procuring the necessary parts and materials to build the transformers. The actual manufacturing process is relatively fast, but getting all parts together is a very lengthy process. The main products of this project are two prototypes of toroidal distribution transformers of 7.62 kV (to be used in a 13.8 kV system) to 2x120 V secondary (standard utilization voltage); one is rated at 25 kVA and the other at 50 kVA. The 25 k

  10. Quasistatic evolution of compact toroids

    International Nuclear Information System (INIS)

    Sgro, A.G.; Spencer, R.L.; Lilliequist, C.

    1981-01-01

    Some results are presented of simulations of the post formation evolution of compact toroids. The simulations were performed with a 1-1/2 D transport code. Such a code makes explicit use of the fact that the shapes of the flux surfaces in the plasma change much more slowly than do the profiles of the physical variables across the flux surfaces. Consequently, assuming that the thermodynamic variables are always equilibrated on a flux surface, one may calculate the time evolution of these profiles as a function of a single variable that labels the flux surfaces. Occasionally, during the calculation these profiles are used to invert the equilibrium equation to update the shapes of the flux surfaces. In turn, these shapes imply certain geometric cofficients, such as A = 2 >, which contain the geometric information required by the 1-D equations

  11. Numerical determination of axisymmetric toroidal magnetohydrodynamic equilibria

    International Nuclear Information System (INIS)

    Johnson, J.L.; Dalhed, H.E.; Greene, J.M.

    1978-07-01

    Numerical schemes for the determination of stationary axisymmetric toroidal equilibria appropriate for modeling real experimental devices are given. Iterative schemes are used to solve the elliptic nonlinear partial differential equation for the poloidal flux function psi. The principal emphasis is on solving the free boundary (plasma-vacuum interface) equilibrium problem where external current-carrying toroidal coils support the plasma column, but fixed boundary (e.g., conducting shell) cases are also included. The toroidal current distribution is given by specifying the pressure and either the poloidal current or the safety factor profiles as functions of psi. Examples of the application of the codes to tokamak design at PPPL are given

  12. Toroidal field ripple effects in large tokamaks

    International Nuclear Information System (INIS)

    Uckan, N.A.; Tsang, K.T.; Callen, J.D.

    1975-01-01

    In an experimental power reactor, the ripple produced by the finite number of toroidal field coils destroys the ideal axisymmetry of the configuration and is responsible for additional particle trapping, loss regions and plasma transport. The effects of toroidal field ripple on the plasma transport coefficient, the loss of alpha particles and energetic injection ions, and the relaxation of toroidal flows are investigated in a new and systematic way. The relevant results are applied to the ORNL-EPR reference design; the maximum ripple there of about 2.2 percent at the outer edge of the plasma column is found to be tolerable from plasma physics considerations

  13. Rotating bubble and toroidal nuclei and fragmentation

    International Nuclear Information System (INIS)

    Royer, G.; Haddad, F.; Jouault, B.

    1995-01-01

    The energy of rotating bubble and toroidal nuclei predicted to be formed in central heavy-ion collisions at intermediate energies is calculated within the generalized rotating liquid drop model. The potential barriers standing in these exotic deformation paths are compared with the three dimensional and plane fragmentation barriers. In the toroidal deformation path of the heaviest systems exists a large potential pocket localised below the plane fragmentation barriers. This might allow the temporary survival of heavy nuclear toroids before the final clusterization induced by the surface and proximity tension. (author)

  14. Influence of toroidal rotation on tearing modes

    Science.gov (United States)

    Cai, Huishan; Cao, Jintao; Li, Ding

    2017-10-01

    Tearing modes stability analysis including toroidal rotation is studied. It is found that rotation affects the stability of tearing modes mainly through the interaction with resistive inner region of tearing mode. The coupling of magnetic curvature with centrifugal force and Coriolis force provides a perturbed perpendicular current, and a return parallel current is induced to affect the stability of tearing modes. Toroidal rotation plays a stable role, which depends on the magnitude of Mach number and adiabatic index Γ, and is independent on the direction of toroidal rotation. For Γ >1, the scaling of growth rate is changed for typical Mach number in present tokamaks. For Γ = 1 , the scaling keeps unchanged, and the effect of toroidal rotation is much less significant, compared with that for Γ >1. National Magnetic Confinement Fusion Science Program and National Science Foundation of China under Grants No. 2014GB106004, No. 2013GB111000, No. 11375189, No. 11075161 and No. 11275260, and Youth Innovation Promotion Association CAS.

  15. LASL toroidal reversed-field pinch programme

    International Nuclear Information System (INIS)

    Baker, D.A.; Buchenauer, C.J.; Burkhardt, L.C.

    1979-01-01

    The determination of the absolute energy loss due to radiation from impurities in the LASL toroidal reversed-field pinch experiment ZT-S is reported. The measurements show that over half the energy loss is accounted for by this mechanism. Thomson-scattering electron density measurements indicate only a gradual increase in temperature as the filling pressure is reduced, indicating an increased energy loss at lower pressures. Cylindrical and toroidal simulations of the experiment indicate either that a highly radiative pinch boundary or anomalous transport is needed to match the experimental results. New effects on the equilibrium due to plasma flows induced by the toroidal geometry are predicted by the toroidal simulations. The preliminary results on the low-temperature discharge cleaning of the ZT-S torus are reported. A description of the upgrade of the ZT-S experiment and the objectives, construction and theoretical predictions for the new ZT-40 experiment are given. (author)

  16. Steady state compact toroidal plasma production

    Science.gov (United States)

    Turner, William C.

    1986-01-01

    Apparatus and method for maintaining steady state compact toroidal plasmas. A compact toroidal plasma is formed by a magnetized coaxial plasma gun and held in close proximity to the gun electrodes by applied magnetic fields or magnetic fields produced by image currents in conducting walls. Voltage supply means maintains a constant potential across the electrodes producing an increasing magnetic helicity which drives the plasma away from a minimum energy state. The plasma globally relaxes to a new minimum energy state, conserving helicity according to Taylor's relaxation hypothesis, and injecting net helicity into the core of the compact toroidal plasma. Controlling the voltage so as to inject net helicity at a predetermined rate based on dissipative processes maintains or increases the compact toroidal plasma in a time averaged steady state mode.

  17. Bow-shaped toroidal field coils

    International Nuclear Information System (INIS)

    Bonanos, P.

    1981-05-01

    Design features of Bow-Shaped Toroidal Field Coils are described and compared with circular and D shaped coils. The results indicate that bow coils can produce higher field strengths, store more energy and be made demountable. The design offers the potential for the production of ultrahigh toroidal fields. Included are representative coil shapes and their engineering properties, a suggested structural design and an analysis of a specific case

  18. Relationships between solid spherical and toroidal harmonics

    OpenAIRE

    Majic, Matt; Ru, Eric C. Le

    2018-01-01

    We derive new relationships expressing solid spherical harmonics as series of toroidal harmonics and vice versa. The expansions include regular and irregular spherical harmonics, ring and axial toroidal harmonics of even and odd parity about the plane of the torus. The expansion coefficients are given in terms of a recurrence relation. As an example application we apply one of the expansions to express the potential of a charged conducting torus on a basis of spherical harmonics.

  19. Low-n shear Alfven spectra in axisymmetric toroidal plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, C.Z.; Chance, M.S.

    1985-11-01

    In toroidal plasmas, the toroidal magnetic field is nonuniform over a magnetic surface and causes coupling of different poloidal harmonics. It is shown both analytically and numerically that the toroidicity not only breaks up the shear Alfven continuous spectrum, but also creates new, discrete, toroidicity-induced shear Alfven eigenmodes with frequencies inside the continuum gaps. Potential applications of the low-n toroidicity-induced shear Alfven eigenmodes on plasma heating and instabilities are addressed. 17 refs., 4 figs.

  20. Low-n shear Alfven spectra in axisymmetric toroidal plasmas

    International Nuclear Information System (INIS)

    Cheng, C.Z.; Chance, M.S.

    1985-11-01

    In toroidal plasmas, the toroidal magnetic field is nonuniform over a magnetic surface and causes coupling of different poloidal harmonics. It is shown both analytically and numerically that the toroidicity not only breaks up the shear Alfven continuous spectrum, but also creates new, discrete, toroidicity-induced shear Alfven eigenmodes with frequencies inside the continuum gaps. Potential applications of the low-n toroidicity-induced shear Alfven eigenmodes on plasma heating and instabilities are addressed. 17 refs., 4 figs

  1. Toroidal Nuclear Matter Distributions of Superheavy Nuclei from Constrained Skyrme-HFB Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Kosior, Amelia [Maria Curie-Sklodowska University, Poland; Staszczak, A. [Maria Curie-Sklodowska University, Poland; Wong, Cheuk-Yin [ORNL

    2017-01-01

    Using the Hartree Fock Bogoliubov (HFB) self-consistent mean-field theory with the SkM* Skyrme energy-density functional, we study nuclear structure properties of even even superheavy nuclei (SHN) of Z = 120 isotopes and N = 184 isotones. The shape of the nucleus along the lowest energy curve as a function of the quadrupole moment Q20 makes a sud- den transition from the oblate spheroids (biconcave discs) to the toroidal shapes, in the region of large oblate quadrupole moments.

  2. Celebrating the Barrel Toroid commissioning

    CERN Multimedia

    Peter Jenni

    ATLAS invited Funding Agency representatives and Laboratory Heads directly related to the funding and construction of the Barrel Toroid for a small ceremony on 13th December 2006 at Point 1, in order to mark the successful first full excitation of the BT (see last eNews). On that date, which was during the December CERN Council week, several of the Funding Agency Heads or their representatives could be present, representing CEA France, INFN Italy, BMBF Germany, Spain, Sweden, Switzerland, Russia, JINR Dubna and CERN. Speeches were delivered by the ATLAS spokesperson Peter Jenni thanking the Funding Partners in the name of the Collaboration, by Magnet Project Leader Herman ten Kate tracing the BT construction history, and by the CERN Director-General Robert Aymar congratulating all those who have contributed to the successful project. Herman ten Kate addressing the delegates. The text of the introductory address by Peter Jenni is reproduced here. "It is a great pleasure for me to welcome you all here...

  3. Toroidal field coil torque structure

    International Nuclear Information System (INIS)

    Gaines, A.L.

    1983-01-01

    A torque structure is disclosed particularly suitable for utilization in a power reactor of the Tokamak-type, and operable therein for purposes of providing support for the toroidal field (TF) coils that comprise one of the major operating components of such a Tokamak power reactor. The subject torque structure takes the form of a frame structure that is operable to enable torque loads acting on the TF coils to be equilibrated as close to the area of force application as feasible. The aforesaid torque structure includes an intercoil structure composed of spacer wedges that are interposed between each adjacent pair of TF coils. The spacer wedges, in turn, consist of bearing plates positioned between the TF coils so as to be in contacting relation therewith and a number of cross plates that are cooperatively associated with the bearing plates so as to form therewith a rigid assembly. The intercoil structure is affixed to a segmented, membrane shell that surrounds, encloses and supports the TF coil frames. Access is had to the interior of the shell through an opening formed for this purpose in a reinforced portion of the shell. Eddy current losses are minimized by insulating the joints formed at the juncture of adjoining segments of the shell

  4. Long-wavelength microinstabilities in toroidal plasmas

    International Nuclear Information System (INIS)

    Tang, W.W.; Rewoldt, G.

    1993-01-01

    Realistic kinetic toroidal eigenmode calculations have been carried out to support a proper assessment of the influence of long-wavelength microturbulence on transport in tokamak plasmas. In order to efficiently evaluate large-scale kinetic behavior extending over many rational surfaces, significant improvements have been made to a toroidal finite element code used to analyze the fully two-dimensional (r,θ) mode structures of trapped-ion and toroidal ion temperature gradient (ITG) instabilities. It is found that even at very long wavelengths, these eigenmodes exhibit a strong ballooning character with the associated radial structure relatively insensitive to ion Landau damping at the rational surfaces. In contrast to the long-accepted picture that the radial extent of trapped-ion instabilities is characterized by the ion-gyroradius-scale associated with strong localization between adjacent rational surfaces, present results demonstrate that under realistic conditions, the actual scale is governed by the large-scale variations in the equilibrium gradients. Applications to recent measurements of fluctuation properties in TFTR L-mode plasmas indicate that the theoretical trends appear consistent with spectral characteristics as well as rough heuristic estimates of the transport level. Benchmarking calculations in support of the development of a three-dimensional toroidal gyrokinetic code indicate reasonable agreement with respect to both the properties of the eigenfunctions and the magnitude of the eigenvalues during the linear phase of the simulations of toroidal ITG instabilities

  5. Effects of toroidicity on resistive tearing modes

    International Nuclear Information System (INIS)

    Izzo, R.; Monticello, D.A.; Manickam, J.; Strauss, H.R.; Grimm, R.; McGuire, K.

    1983-03-01

    A reduced set of resistive MHD equations is solved numerically in three dimensions to study the stability of tokamak plasmas. Toroidal effects are included self-consistently to leading and next order in inverse aspect ratio, epsilon. The equations satisfy an energy integral. In addition, the momentum equation yields the Grad-Shafranov equation correct to all orders in epsilon. Low beta plasma are studied using several different q-profiles. In all cases, the linear growth rates are reduced by finite toroidicity. Excellent agreement with resistive PEST is obtianed. In some cases, toroidal effects lead to complete stabilization of the mode. Nonlinear results show smaller saturated island widths for finite aspect ratio compared to the cylindrical limit. If the current channel is wide enough so as to produce steep gradients towards the outside of the plasma, both the finite aspect ratio cases and cylindrical cases disrupt

  6. PDX toroidal field coils stress analysis

    International Nuclear Information System (INIS)

    Nikodem, Z.D.; Smith, R.A.

    1975-01-01

    A method used in the stress analysis of the PDX toroidal field coil is developed. A multilayer coil design of arbitrary dimensions in the shape of either a circle or an oval is considered. The analytical model of the coil and the supporting coil case with connections to the main support structure is analyzed using the finite element technique. The three dimensional magnetic fields and the non-uniform body forces which are a loading condition on a coil due to toroidal and poloidal fields are calculated. The method of analysis permits rapid and economic evaluations of design changes in coil geometry as well as in coil support structures. Some results pertinent to the design evolution and their comparison are discussed. The results of the detailed stress analysis of the final coil design due to toroidal field, poloidal field and temperature loads are presented

  7. Current control necessary for toroidal plasma equilibrium

    International Nuclear Information System (INIS)

    Nagao, S.

    1987-01-01

    It is shown that a significant amount of dipole current is necessary for the plasma equilibrium of toroidal configurations in general. Through the vector product with the poloidal field, this dipole current force has to balance with the hoop force of plasma pressure itself of the annular shape. The measurement of such a current of dipole type may be interesting for the confirmation of the plasma equilibrium in the toroidal system. Moreover it is certained that there is a new mode of a tokamak operation with such a dipole current component and with smaller vertical field than that based on the classical tokamak theory. (author) [pt

  8. Models for large superconducting toroidal magnet systems

    International Nuclear Information System (INIS)

    Arendt, F.; Brechna, H.; Erb, J.; Komarek, P.; Krauth, H.; Maurer, W.

    1976-01-01

    Prior to the design of large GJ toroidal magnet systems it is appropriate to procure small scale models, which can simulate their pertinent properties and allow to investigate their relevant phenomena. The important feature of the model is to show under which circumstances the system performance can be extrapolated to large magnets. Based on parameters such as the maximum magnetic field and the current density, the maximum tolerable magneto-mechanical stresses, a simple method of designing model magnets is presented. It is shown how pertinent design parameters are changed when the toroidal dimensions are altered. In addition some conductor cost estimations are given based on reactor power output and wall loading

  9. Toroidal Precession as a Geometric Phase

    Energy Technology Data Exchange (ETDEWEB)

    J.W. Burby and H. Qin

    2012-09-26

    Toroidal precession is commonly understood as the orbit-averaged toroidal drift of guiding centers in axisymmetric and quasisymmetric configurations. We give a new, more natural description of precession as a geometric phase effect. In particular, we show that the precession angle arises as the holonomy of a guiding center's poloidal trajectory relative to a principal connection. The fact that this description is physically appropriate is borne out with new, manifestly coordinate-independent expressions for the precession angle that apply to all types of orbits in tokamaks and quasisymmetric stellarators alike. We then describe how these expressions may be fruitfully employed in numerical calculations of precession.

  10. The effect of sheared toroidal rotation on pressure driven magnetic islands in toroidal plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Hegna, C. C. [Departments of Engineering Physics and Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

    2016-05-15

    The impact of sheared toroidal rotation on the evolution of pressure driven magnetic islands in tokamak plasmas is investigated using a resistive magnetohydrodynamics model augmented by a neoclassical Ohm's law. Particular attention is paid to the asymptotic matching data as the Mercier indices are altered in the presence of sheared flow. Analysis of the nonlinear island Grad-Shafranov equation shows that sheared flows tend to amplify the stabilizing pressure/curvature contribution to pressure driven islands in toroidal tokamaks relative to the island bootstrap current contribution. As such, sheared toroidal rotation tends to reduce saturated magnetic island widths.

  11. Extreme black hole with an electric dipole moment

    International Nuclear Information System (INIS)

    Horowitz, G.T.; Tada, T.

    1996-01-01

    We construct a new extreme black hole solution in a toroidally compactified heterotic string theory. The black hole saturates the Bogomol close-quote nyi bound, has zero angular momentum, but a nonzero electric dipole moment. It is obtained by starting with a higher-dimensional rotating charged black hole, and compactifying one direction in the plane of rotation. copyright 1996 The American Physical Society

  12. Assembling Transgender Moments

    Science.gov (United States)

    Greteman, Adam J.

    2017-01-01

    In this article, the author seeks to assemble moments--scholarly, popular, and aesthetic--in order to explore the possibilities that emerge as moments collect in education's encounters with the needs, struggles, and possibilities of transgender lives and practices. Assembling moments, the author argues, illustrates the value of "moments"…

  13. Toroidal groups line bundles, cohomology and quasi-Abelian varieties

    CERN Document Server

    Kopfermann, Klaus

    2001-01-01

    Toroidal groups are the connecting link between torus groups and any complex Lie groups. Many properties of complex Lie groups such as the pseudoconvexity and cohomology are determined by their maximal toroidal subgroups. Quasi-Abelian varieties are meromorphically separable toroidal groups. They are the natural generalisation of the Abelian varieties. Nevertheless, their behavior can be completely different as the wild groups show.

  14. An integral equation-based numerical solver for Taylor states in toroidal geometries

    Science.gov (United States)

    O'Neil, Michael; Cerfon, Antoine J.

    2018-04-01

    We present an algorithm for the numerical calculation of Taylor states in toroidal and toroidal-shell geometries using an analytical framework developed for the solution to the time-harmonic Maxwell equations. Taylor states are a special case of what are known as Beltrami fields, or linear force-free fields. The scheme of this work relies on the generalized Debye source representation of Maxwell fields and an integral representation of Beltrami fields which immediately yields a well-conditioned second-kind integral equation. This integral equation has a unique solution whenever the Beltrami parameter λ is not a member of a discrete, countable set of resonances which physically correspond to spontaneous symmetry breaking. Several numerical examples relevant to magnetohydrodynamic equilibria calculations are provided. Lastly, our approach easily generalizes to arbitrary geometries, both bounded and unbounded, and of varying genus.

  15. On the stabilization of toroidal pinches by finite larmor radius effects and toroidal magnetic field

    International Nuclear Information System (INIS)

    Singh, R.; Weiland, J.

    1989-01-01

    The radial eigenvalue problem for internal modes in a large aspect ratio toriodal pinch has been solved. A particularly stable regime for a weak but nonzero toroidal magnetic field has been found. (31 refs.)

  16. ATLAS: Full power for the toroid magnet

    CERN Multimedia

    2006-01-01

    The 9th of November was a memorable day for ATLAS. Just before midnight, the gigantic Barrel toroid magnet reached its nominal field of 4 teslas in the coil windings, with an electrical current of 21000 amperes (21 kA) passing through the eight superconducting coils (as seen on the graph). This achievement was obtained after several weeks of commissioning. The ATLAS Barrel Toroid was first cooled down for about six weeks in July-August to -269°C (4.8 K) and then powered up step-by-step in successive test sessions to 21 kA. This is 0.5 kA above the current required to produce the nominal magnetic field. Afterwards, the current was safely switched off and the stored magnetic energy of 1.1 gigajoules was dissipated in the cold mass, raising its temperature to a safe -218°C (55 K). 'We can now say that the ATLAS Barrel Toroid is ready for physics,' said Herman ten Kate, project leader for the ATLAS magnet system. The ATLAS barrel toroid magnet is the result of a close collaboration between the magnet la...

  17. Celebration for the ATLAS Barrel Toroid magnet

    CERN Multimedia

    2007-01-01

    Representatives from Funding Agencies and Barrel Toroid Magnet Laboratories during the ceremony. From left to right: Jean Zinn-Justin (Head of DAPNIA/CEA/Saclay), CERN Director-General Robert Aymar, and Roberto Petronzio (President INFN).Allan Clark (DPNC University Geneva) and Enrique Fernandez (IFAE Barcelona) were among the guests visiting the ATLAS cavern. The barrel toroid is visible in the background. A celebration took place at Point 1 on 13 December to toast the recent powering-up of the ATLAS barrel toroid magnet to full field (Bulletin No. 47-48/06). About 70 guests were invited to attend, mainly composed of representatives from funding partners and key members of the laboratory management teams of the barrel toroid magnet, representing CEA France, INFN Italy, BMBF Germany, Spain, Sweden, Switzerland, Russia, JINR Dubna and CERN. An introductory speech by ATLAS spokesperson Peter Jenni the scene for evening. This was followed by the ATLAS magnet system project leader Herman Ten Kate's account of the...

  18. ATLAS Barrel Toroid magnet reached nominal field

    CERN Multimedia

    2006-01-01

     On 9 November the barrel toroid magnet reached its nominal field of 4 teslas, with an electrical current of 21 000 amperes (21 kA) passing through the eight superconducting coils as shown on this graph

  19. Design of the TPX outboard toroidal limiters

    International Nuclear Information System (INIS)

    Schaubel, K.M.; Anderson, P.M.; Baxi, C.B.

    1995-01-01

    The Tokamak Physics Experiment outboard limiter system incorporates the passive stabilizer plates, the ripple armor, the toroidal break and the support structures. These components are designed to withstand substantial steady state heat loads and high mechanical forces caused by plasma disruptions. The design of these components has been developed to deal with the challenging thermal, structural and remote handling requirements

  20. Curvature driven instabilities in toroidal plasmas

    International Nuclear Information System (INIS)

    Andersson, P.

    1986-11-01

    The electromagnetic ballooning mode, the curvature driven trapped electron mode and the toroidally induced ion temperature gradient mode have been studies. Eigenvalue equations have been derived and solved both numerically and analytically. For electromagnetic ballooning modes the effects of convective damping, finite Larmor radius, higher order curvature terms, and temperature gradients have been investigated. A fully toroidal fluid ion model has been developed. It is shown that a necessary and sufficient condition for an instability below the MHD limit is the presence of an ion temperature gradient. Analytical dispersion relations giving results in good agreement with numerical solutions are also presented. The curvature driven trapped electron modes are found to be unstable for virtually all parameters with growth rates of the order of the diamagnetic drift frequency. Studies have been made, using both a gyrokinetic ion description and the fully toroidal ion model. Both analytical and numerical results are presented and are found to be in good agreement. The toroidally induced ion temperature gradients modes are found to have a behavior similar to that of the curvature driven trapped electron modes and can in the electrostatic limit be described by a simple quadratic dispersion equation. (author)

  1. Toroidal 12 cavity klystron : a novel approach

    International Nuclear Information System (INIS)

    Hazarika, A.B.R.

    2013-01-01

    A toroidal 12 cavity klystron is designed to provide with high energy power with the high frequency microwave RF- plasma generated from it. The cavities are positioned in clock hour positions. The theoretical modeling and designing is done to study the novel approach. (author)

  2. Spontaneous pneumothorax

    Directory of Open Access Journals (Sweden)

    Davari R

    1996-07-01

    Full Text Available A case with bilateral spontaneous pneumothorax was presented. Etiology, mechanism, and treatment were discussed on the review of literature. Spontaneous Pneumothorax is a clinical entity resulting from a sudden non traumatic rupture of the lung. Biach reported in 1880 that 78% of 916 patients with spontaneous pneumothorax had tuberculosis. Kjergaard emphasized 1932 the primary importance of subpleural bleb disease. Currently the clinical spectrum of spontaneous pneumothorax seems to have entered a third era with the recognition of the interstitial lung disease and AIDS as a significant etiology. Standard treatment is including: observation, thoracocentesis, tube thoracostomy. Chemical pleurodesis, bullectomy or wedge resection of lung with pleural abrasion and occasionally pleurectomy. Little information has been reported regarding the efficacy of such treatment in spontaneous pneumothorax secondary to non bleb disease

  3. Shielding and synchrotron radiation in toroidal waveguide

    Directory of Open Access Journals (Sweden)

    G. V. Stupakov

    2003-03-01

    Full Text Available We develop a new approach to the calculation of the synchrotron radiation in a toroidal vacuum chamber. Using a small parameter ϵ=sqrt[a/R], where a is the characteristic size of the cross section of the toroid and R is the bending radius, we simplify Maxwell’s equations assuming that the characteristic frequency of the modes ω∼c/aϵ and neglect terms of higher order in ϵ. For a rectangular cross section of the waveguide, we find an analytical solution of the equations and analyze their asymptotics at very high frequency. We then obtain an equation which gives radiation into each synchronous mode. We demonstrate the flexibility of the new method by calculating the frequencies and the loss factors for the lowest modes in square and round waveguides.

  4. Form coefficient of helical toroidal solenoids

    International Nuclear Information System (INIS)

    Amelin, V.Z.; Kunchenko, V.B.

    1982-01-01

    For toroidal solenoids with continuous spiral coil, winded according to the laws of equiinclined and simple cylindrical spirals with homogeneous, linearly increasing to the coil periphery and ''Bitter'' distribution of current density, the analytical expressions for the dependence between capacity consumed and generated magnetic field, expressions for coefficients of form similar to Fabry coefficient for cylindrical solenoids are obtained and dependence of the form coefficient and relative volume of solenoid conductor on the number of revolutions of screw line per one circumvention over the large torus radius is also investigated. Analytical expressions of form coefficients and graphical material permit to select the optimum geometry as to capacity consumed both for spiral (including ''force-free'') and conventional toroidal solenoids of magnetic systems in thermonulear installations

  5. Toroidal plasma response to external fields

    International Nuclear Information System (INIS)

    Storer, R.G.

    1998-01-01

    Toroidal plasmas respond to external driving fields in a way which is determined by the coupling of these fields to the spectrum of the plasma. We have extended the toroidal resistive magnetohydrodynamic spectral code, SPECTOR, to include the effects of external fields on tokamak-like plasmas. The code is capable of determining both the stable and unstable modes and also the response to helical applied fields with arbitrary mode structure. Resistivity changes the continuous regions of the ideal MHD spectrum into a set of discrete eigenvalues lying along lines in the complex frequency plane with a spacing which is related to the inverse of the square root of the magnetic Reynolds number. Results are presented which relate the spectral distribution to the plasma response as a function of frequency. (author)

  6. METHODS TO DEVELOP A TOROIDAL SURFACE

    Directory of Open Access Journals (Sweden)

    DANAILA Ligia

    2017-05-01

    Full Text Available The paper work presents two practical methods to draw the development of a surface unable to be developed applying classical methods of Descriptive Geometry, the toroidal surface, frequently met in technical practice. The described methods are approximate ones; the development is obtained with the help of points. The accuracy of the methods is given by the number of points used when drawing. As for any other approximate method, when practically manufactured the development may need to be adjusted on site.

  7. Stellarator approach to toroidal plasma confinement

    International Nuclear Information System (INIS)

    Johnson, J.L.

    1981-12-01

    An overview is presented of the development and current status of the stellarator approach to controlled thermonuclear confinement. Recent experimental, theoretical, and systems developments have made this concept a viable option for the evolution of the toroidal confinement program. Some experimental study of specific problems associated with departure from two-dimensional symmetry must be undertaken before the full advantages and opportunities of steady-state, net-current-free operation can be realized

  8. Kinetic Damping of Toroidal Alfven Eigenmodes

    International Nuclear Information System (INIS)

    Fu, G.Y.; Berk, H.L.; Pletzer, A.

    2005-01-01

    The damping of Toroidal Alfven Eigenmodes in JET plasmas is investigated by using a reduced kinetic model. Typically no significant damping is found to occur near the center of the plasma due to mode conversion to kinetic Alfven waves. In contrast, continuum damping from resonance near the plasma edge may be significant, and when it is, it gives rise to damping rates that are compatible with the experimental observations

  9. Mirror theory applied to toroidal systems

    International Nuclear Information System (INIS)

    Cohen, R.H.

    1987-01-01

    Central features of a mirror plasma are strong departures from Maxwellian distribution functions, ambipolar potentials and densities which vary along a field line, end losses, and the mirror field itself. To examine these features, mirror theorists have developed analytical and numerical techniques to solve the Fokker-Planck equation, evaluate the potentials consistent with the resulting distribution functions, and assess the microstability of these distributions. Various combinations of mirror-plasma features are present and important in toroidal plasmas as well, particularly in the edge region and in plasmas with strong rf heating. In this paper we survey problems in toroidal plasmas where mirror theory and computational techniques are applicable, and discuss in more detail three specific examples: calculation of the toroidal generalization of the Spitzer-Haerm distribution function (from which trapped-particle effects on current drive can be calculated), evaluation of the nonuniform potential and density set up by pulsed electron-cyclotron heating, and calculation of steady-state distribution functions in the presence of strong rf heating and collisions. 37 refs

  10. ISX toroidal field coil design and analysis

    International Nuclear Information System (INIS)

    Hussung, R.O.; Lousteau, D.C.; Johnson, N.E.; Weed, R.A.

    1975-01-01

    Structural design and analysis aspects of the toroidal field coils for the Impurity Study Experiment (ISX) tokamak are discussed. The overall mechanical design of ISX is predicated on the ability to remove the upper segment of the toroidal field coils to allow access to the toroidal vacuum vessel. The high current, 120 kA, capability of the new 74 MW power supply, coupled with the modest field requirement of ISX, allows the use of room temperature copper coils. Seventy-two turns, grouped into 18 coils, generate a magnet field of 18 kG at the major radius of 90 cm. Finite element structural analysis codes were utilized to determine the distribution of stresses and deflections around a typical turn. Initial material distribution on a coil was sized using the two-dimensional program FEATS. The resulting coil design was then coupled to the center bucking and out-of-plane restraint systems utilizing the NASTRAN code. The boundary conditions for the analytical models used in the two programs were then iterated, reaching satisfactory agreement as to stress contours and location for the joints

  11. Magnetic moments of baryons

    International Nuclear Information System (INIS)

    Lipkin, H.J.

    1983-06-01

    The new experimental values of hyperon magnetic moments are compared with sum rules predicted from general quark models. Three difficulties are encountered which are not easily explained by simple models. The isovector contributions of nonstrange quarks to hyperon moments are smaller than the corresponding contribution to nucleon moments, indicating either appreciable configuration mixing present in hyperon wave functions and absent in nucleons or an additional isovector contribution beyond that of valence quarks; e.g. from a pion cloud. The large magnitude of the ω - moment may indicate that the strange quark contribution to the ω moments is considerably larger than the value μ(#betta#) predicted by simple models which have otherwise been very successful. The set of controversial values from different experiments of the μ - moment include a value very close to -(1/2)μ(μ + ) which would indicate that strange quarks do not contribute at all to the μ moments. (author)

  12. Solvents level dipole moments.

    Science.gov (United States)

    Liang, Wenkel; Li, Xiaosong; Dalton, Larry R; Robinson, Bruce H; Eichinger, Bruce E

    2011-11-03

    The dipole moments of highly polar molecules measured in solution are usually smaller than the molecular dipole moments that are calculated with reaction field methods, whereas vacuum values are routinely calculated in good agreement with available vapor phase data. Whether from Onsager's theory (or variations thereof) or from quantum mechanical methods, the calculated molecular dipoles in solution are found to be larger than those measured. The reason, of course, is that experiments measure the net dipole moment of solute together with the polarized (perturbed) solvent "cloud" surrounding it. Here we show that the reaction field charges that are generated in the quantum mechanical self-consistent reaction field (SCRF) method give a good estimate of the net dipole moment of the solute molecule together with the moment arising from the reaction field charges. This net dipole is a better description of experimental data than the vacuum dipole moment and certainly better than the bare dipole moment of the polarized solute molecule.

  13. Fluid models for kinetic effects in toroidal plasmas

    International Nuclear Information System (INIS)

    Smolyakov, A.I.; Hirose, A.; Yagi, M.; Callen, J.D.

    1995-01-01

    Fluid models for toroidal plasma are considered paying particular attention to the effects of particle motion along the equilibrium magnetic field. It is shown that the basic fluid equations can be obtained either as moments of the drift-kinetic equation, or from the standard fluid equations by expanding them in 1/B small parameter. It is shown that the collisionless gyroviscosity accounts for the effects of the particle magnetic drift in the parallel component of the momentum balance equation. Simple truncated model of the plasma response for arbitrary ω D (magnetic drift frequency) and k parallel V t (parallel transit frequency) is proposed. In the absence of resonances, which can be inhibited by the particle magnetic drift, this model recovers the exact kinetic results with satisfactory accuracy. In general case, the kinetic closure for the effects of the particle motion along the magnetic field is suggested in terms of the parallel viscosity and the heat flux. They are directly calculated from the linear drift-kinetic equation. Simplified expressions in the different asymptotic limits are derived

  14. Noteworthy moments and people!

    CERN Multimedia

    Claudia Marcelloni de Oliveira

    The man with nerves of steel and one steady finger: Gerard Mouquin operating the main crane with a joy-stick-like remote control while the 220-ton End-Cap Toroid Magnet is suspended mid-air above the access shaft. His job was hanging by a thread... The woman with nerves of steel: Sylvie Prodon, head of the logistic section responsible for all transport at CERN was supervising the delicate operation of taking the first End-Cap Toroid down to the ATLAS cavern. The sight from Side A after complete insertion of the Inner Detector End-Cap A and pushing back the End-Cap Calorimeter into place, making room for the Toroid End-Cap A. Lots of pondering took place during the testing of the pixel insertion procedure. The tooling which will be used in the cavern to insert the pixel within the silicon detector was fully tested at the surface in the SR1 building by having the whole detector passing through the insertion template when the pixel detector was placed within its transportation carriage. The...

  15. Application of plasma focus device to compression of toroidal plasma

    International Nuclear Information System (INIS)

    Ikuta, Kazunari

    1980-01-01

    A new concept of compressing a toroidal plasma using a plasma focus device is considered. Maximum compression ratio of toroidal plasma is determined merely by the initial density ratio of the toroidal plasma to a sheet plasma in a focus device because of the Rayleigh-Taylor instability. An initiation senario of plasma-linear is also proposed with a possible application of this concepts to the creation of a burning plasma in reversed field configurations, i.e., burning plasma vortex. (author)

  16. A 'rational' explanation of resonant surfaces in toroidal plasmas

    International Nuclear Information System (INIS)

    Cross, R.C.

    1983-05-01

    Resonant surfaces are of fundamental importance in toroidal plasmas, particularly in relation to stability theory. A simple explanation as to why these surfaces are 'resonant' is given in terms of the propagation of localized torsional Alfven and ion acoustic wave packets. These packets are guided along helical field lines in toroidal plasmas, leading to the formation of unstable standing waves on those field lines which close on themselves after one or more toroidal revolutions

  17. Toroidal magnetic detector for high resolution measurement of muon momenta

    Science.gov (United States)

    Bonanos, Peter

    1992-01-01

    A muon detector system including central and end air-core superconducting toroids and muon detectors enclosing a central calorimeter/detector. Muon detectors are positioned outside of toroids and all muon trajectory measurements are made in a nonmagnetic environment. Internal support for each magnet structure is provided by sheets, located at frequent and regularly spaced azimuthal planes, which interconnect the structural walls of the toroidal magnets. In a preferred embodiment, the shape of the toroidal magnet volume is adjusted to provide constant resolution over a wide range of rapidity.

  18. Spontaneous deregulation

    NARCIS (Netherlands)

    Edelman, Benjamin; Geradin, Damien

    Platform businesses such as Airbnb and Uber have risen to success partly by sidestepping laws and regulations that encumber their traditional competitors. Such rule flouting is what the authors call “spontaneous private deregulation,” and it’s happening in a growing number of industries. The authors

  19. Lepton dipole moments

    CERN Document Server

    Marciano, William J

    2010-01-01

    This book provides a self-contained description of the measurements of the magnetic dipole moments of the electron and muon, along with a discussion of the measurements of the fine structure constant, and the theory associated with magnetic and electric dipole moments. Also included are the searches for a permanent electric dipole moment of the electron, muon, neutron and atomic nuclei. The related topic of the transition moment for lepton flavor violating processes, such as neutrinoless muon or tauon decays, and the search for such processes are included as well. The papers, written by many o

  20. General Atomic's superconducting toroidal field coil concept

    International Nuclear Information System (INIS)

    Alcorn, J.; Purcell, J.

    1978-01-01

    General Atomic's concept for a superconducting toroidal field coil is presented. The concept is generic for large tokamak devices, while a specific design is indicated for a 3.8 meter (major radius) ignition/burn machine. The concept utilizes bath cooled NbTi conductor to generate a peak field of 10 tesla at 4.2 K. The design is simple and straightforward, requires a minimum of developmental effort, and draws extensively upon the perspective of past experience in the design and construction of large superconducting magnets for high energy physics. Thus, the primary emphasis is upon economy, reliability, and expeditious construction scheduling. (author)

  1. Electrical disruption in toroidal plasma of hydrogen

    International Nuclear Information System (INIS)

    Roberto, M.; Silva, C.A.B.; Goes, L.C.S.; Sudano, J.P.

    1991-01-01

    The initial phase of ionization of a toroidal plasma produced in hydrogen was investigated using zero-dimensional model. The model describes the temporal evolution of plasma by spatial medium of particle density and temperature, on whole plasma volume. The energy and particle (electrons and ions) balance equations are considered. The electron loss is due to ambipolar diffusion in the presence of magnetic field. The electron energy loss involves ionization, Coulomb interaction and diffusion. The ohmic heating converter gives the initial voltage necessary to disruption. (M.C.K.)

  2. 3D Printing the ATLAS' barrel toroid

    CERN Document Server

    Goncalves, Tiago Barreiro

    2016-01-01

    The present report summarizes my work as part of the Summer Student Programme 2016 in the CERN IR-ECO-TSP department (International Relations – Education, Communication & Outreach – Teacher and Student Programmes). Particularly, I worked closely with the S’Cool LAB team on a science education project. This project included the 3D designing, 3D printing, and assembling of a model of the ATLAS’ barrel toroid. A detailed description of the project' development is presented and a short manual on how to use 3D printing software and hardware is attached.

  3. Toroidal magnetic field system for 2-MA reversed-field pinch experiment

    Science.gov (United States)

    Melton, J. G.; Linton, T. W.

    The engineering design of the toroidal magnetic field (TF) system for a 2-MA Reversed Field Pinch experiment (ZT-H) is described. ZT-H is designed with major radius 2.15 meters, minor radius 0.40 meters, and a peak toroidal magnetic field of 0.85 Tesla. The requirement for highly uniform fields, with spatial ripple 0.2% leads to a design with 72 equally spaced circular TF coils, located at minor radius 0.6 meters, carrying a maximum current of 9.0 MA. The coils are driven by a 12-MJ capacitor bank which is allowed to ring in order to aid the reversal of magnetic field. A stress analysis is presented, based upon calculated loop tension, centering force, and overturning moment, treating these as a combination of static loads and considering that the periodic nature of the loading causes little amplification. The load transfer of forces and moments is considered as a stress distribution resisted by the coils, support structures, wedges, and the structural shell.

  4. Nuclear Anapole Moments

    International Nuclear Information System (INIS)

    Michael Ramsey-Musolf; Wick Haxton; Ching-Pang Liu

    2002-01-01

    Nuclear anapole moments are parity-odd, time-reversal-even E1 moments of the electromagnetic current operator. Although the existence of this moment was recognized theoretically soon after the discovery of parity nonconservation (PNC), its experimental isolation was achieved only recently, when a new level of precision was reached in a measurement of the hyperfine dependence of atomic PNC in 133Cs. An important anapole moment bound in 205Tl also exists. In this paper, we present the details of the first calculation of these anapole moments in the framework commonly used in other studies of hadronic PNC, a meson exchange potential that includes long-range pion exchange and enough degrees of freedom to describe the five independent S-P amplitudes induced by short-range interactions. The resulting contributions of pi-, rho-, and omega-exchange to the single-nucleon anapole moment, to parity admixtures in the nuclear ground state, and to PNC exchange currents are evaluated, using configuration-mixed shell-model wave functions. The experimental anapole moment constraints on the PNC meson-nucleon coupling constants are derived and compared with those from other tests of the hadronic weak interaction. While the bounds obtained from the anapole moment results are consistent with the broad ''reasonable ranges'' defined by theory, they are not in good agreement with the constraints from the other experiments. We explore possible explanations for the discrepancy and comment on the potential importance of new experiments

  5. Nuclear Anapole Moments

    Energy Technology Data Exchange (ETDEWEB)

    Michael Ramsey-Musolf; Wick Haxton; Ching-Pang Liu

    2002-03-29

    Nuclear anapole moments are parity-odd, time-reversal-even E1 moments of the electromagnetic current operator. Although the existence of this moment was recognized theoretically soon after the discovery of parity nonconservation (PNC), its experimental isolation was achieved only recently, when a new level of precision was reached in a measurement of the hyperfine dependence of atomic PNC in 133Cs. An important anapole moment bound in 205Tl also exists. In this paper, we present the details of the first calculation of these anapole moments in the framework commonly used in other studies of hadronic PNC, a meson exchange potential that includes long-range pion exchange and enough degrees of freedom to describe the five independent S-P amplitudes induced by short-range interactions. The resulting contributions of pi-, rho-, and omega-exchange to the single-nucleon anapole moment, to parity admixtures in the nuclear ground state, and to PNC exchange currents are evaluated, using configuration-mixed shell-model wave functions. The experimental anapole moment constraints on the PNC meson-nucleon coupling constants are derived and compared with those from other tests of the hadronic weak interaction. While the bounds obtained from the anapole moment results are consistent with the broad ''reasonable ranges'' defined by theory, they are not in good agreement with the constraints from the other experiments. We explore possible explanations for the discrepancy and comment on the potential importance of new experiments.

  6. Electric dipole moments reconsidered

    International Nuclear Information System (INIS)

    Rupertsberger, H.

    1989-01-01

    The electric dipole moments of elementary particles, atoms, molecules and their connection to the electric susceptibility are discussed for stationary states. Assuming rotational invariance it is emphasized that for such states only in the case of a parity and time reversal violating interaction the considered particles can obtain a nonvanishing expectation value for the electric dipole moment. 1 fig., 13 refs. (Author)

  7. Moment graphs and representations

    DEFF Research Database (Denmark)

    Jantzen, Jens Carsten

    2012-01-01

    Moment graphs and sheaves on moment graphs are basically combinatorial objects that have be used to describe equivariant intersectiion cohomology. In these lectures we are going to show that they can be used to provide a direct link from this cohomology to the representation theory of simple Lie...

  8. Compact toroid formation, compression, and acceleration

    International Nuclear Information System (INIS)

    Degnan, J.H.; Bell, D.E.; Baca, G.P.; Dearborn, M.E.; Douglas, M.R.; Englert, S.E.; Englert, T.J.; Holmes, J.H.; Hussey, T.W.; Kiuttu, G.F.; Lehr, F.M.; Marklin, G.J.; Mullins, B.W.; Peterkin, R.E.; Price, D.W.; Roderick, N.F.; Ruden, E.L.; Turchi, P.J.; Coffey, S.K.; Seiler, S.W.; Bird, G.

    1992-01-01

    Research on the formation, compression, and acceleration of milligram Compact Toroids (CTs) will be discussed. This includes experiments with 2-stage coaxial gun discharges and calculations including 2D- MHD. The CTs are formed by 110 μf, 70 KV, 2 MA, 3 μs rise time discharges into 2 mg gas puffs in a 90 cm inner diameter, 7.6 cm gap coaxial gun with approximately 0.15 Tesla of radial-axial initial magnetic field. Reconnection at the neck of the toroidal magnetized plasma bubble extracted from the first stage gun forms the CT. Trapping, relaxation to a minimum energy Taylor state is observed with magnetic probe arrays. Low energy (few hundred KJ, 2 MA) acceleration in straight coaxial geometry, and high energy acceleration using a conical compression stage are discussed. The Phillips Laboratory 1,300 μf, 120 KV, 9.4 MJ SHIVA STAR capacitor bank is used for the acceleration discharge. The charging and triggering of the 36-module bank has been modified to permit use of any multiple of three modules. Highlights of fast photography, current, voltage, magnetic probe array, optical spectroscopy, interferometry, VUV, and higher energy radiation data and 2D-MHD calculations will be presented. Considerably more detail is presented in companion papers

  9. Transport and Dynamics in Toroidal Fusion Systems

    Energy Technology Data Exchange (ETDEWEB)

    Schnack, Dalton D

    2006-05-16

    This document reports the successful completion of the OFES Theory Milestone for FY2005, namely, Perform parametric studies to better understand the edge physics regimes of laboratory experiments. Simulate at increased resolution (up to 20 toroidal modes), with density evolution, late into the nonlinear phase and compare results from different types of edge modes. Simulate a single case including a study of heat deposition on nearby material walls. The linear stability properties and nonlinear evolution of Edge Localized Modes (ELMs) in tokamak plasmas are investigated through numerical computation. Data from the DIII-D device at General Atomics (http://fusion.gat.com/diii-d/) is used for the magnetohydrodynamic (MHD) equilibria, but edge parameters are varied to reveal important physical effects. The equilibrium with very low magnetic shear produces an unstable spectrum that is somewhat insensitive to dissipation coefficient values. Here, linear growth rates from the non-ideal NIMROD code (http://nimrodteam.org) agree reasonably well with ideal, i.e. non-dissipative, results from the GATO global linear stability code at low toroidal mode number (n) and with ideal results from the ELITE edge linear stability code at moderate to high toroidal mode number. Linear studies with a more realistic sequence of MHD equilibria (based on DIII-D discharge 86166) produce more significant discrepancies between the ideal and non-ideal calculations. The maximum growth rate for the ideal computations occurs at toroidal mode index n=10, whereas growth rates in the non-ideal computations continue to increase with n unless strong anisotropic thermal conduction is included. Recent modeling advances allow drift effects associated with the Hall electric field and gyroviscosity to be considered. A stabilizing effect can be observed in the preliminary results, but while the distortion in mode structure is readily apparent at n=40, the growth rate is only 13% less than the non-ideal MHD

  10. The moment problem

    CERN Document Server

    Schmüdgen, Konrad

    2017-01-01

    This advanced textbook provides a comprehensive and unified account of the moment problem. It covers the classical one-dimensional theory and its multidimensional generalization, including modern methods and recent developments. In both the one-dimensional and multidimensional cases, the full and truncated moment problems are carefully treated separately. Fundamental concepts, results and methods are developed in detail and accompanied by numerous examples and exercises. Particular attention is given to powerful modern techniques such as real algebraic geometry and Hilbert space operators. A wide range of important aspects are covered, including the Nevanlinna parametrization for indeterminate moment problems, canonical and principal measures for truncated moment problems, the interplay between Positivstellensätze and moment problems on semi-algebraic sets, the fibre theorem, multidimensional determinacy theory, operator-theoretic approaches, and the existence theory and important special topics of multidime...

  11. Toroidal asymmetries in divertor impurity influxes in NSTX

    Directory of Open Access Journals (Sweden)

    F. Scotti

    2017-08-01

    Full Text Available Toroidal asymmetries in divertor carbon and lithium influxes were observed in NSTX, due to toroidal differences in surface composition, tile leading edges, externally-applied three-dimensional (3D fields and toroidally-localized edge plasma modifications due to radio frequency heating. Understanding toroidal asymmetries in impurity influxes is critical for the evaluation of total impurity sources, often inferred from measurements with a limited toroidal coverage. The toroidally-asymmetric lithium deposition induced asymmetries in divertor lithium influxes. Enhanced impurity influxes at the leading edge of divertor tiles were the main cause of carbon toroidal asymmetries and were enhanced during edge localized modes. Externally-applied 3D fields led to strike point splitting and helical lobes observed in divertor impurity emission, but marginal changes to the toroidally-averaged impurity influxes. Power coupled to the scrape-off layer SOL plasma during radio frequency (RF heating of H-mode discharges enhanced impurity influxes along the non-axisymmetric divertor footprint of flux tubes connecting to plasma in front of the RF antenna.

  12. Low-frequency fluctuations in a pure toroidal magnetized plasma

    Indian Academy of Sciences (India)

    Abstract. A magnetized, low-β plasma in pure toroidal configuration is formed and ex- tensively studied with ion mass as control parameter. Xenon, krypton and argon plasmas are formed at a fixed toroidal magnetic field of 0.024 T, with a peak density of ~1011 cm−3, ~4 × 1010 cm −3 and ~2 × 1010 cm −3 respectively.

  13. Formation of a compact toroid for enhanced efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Mozgovoy, A. G. [P.N. Lebedev Physical Institute, Moscow 119991 (Russian Federation); Romadanov, I. V.; Ryzhkov, S. V., E-mail: ryzhkov@power.bmstu.ru [Bauman Moscow State Technical University, Moscow 105005 (Russian Federation)

    2014-02-15

    We report here our results on the formation of a plasma configuration with the generic name of compact toroid (CT). A method of compact toroid formation to confine, heat and compress a plasma is investigated. Formation of a compact torus using an additional toroidal magnetic field helps to increase the plasma current to a maintainable level of the original magnetic field. We design the Compact Toroid Challenge (CTC) experiment in order to improve the magnetic flux trapping during field reversal in the formation of a compact toroid. The level of the magnetic field immersed in the plasma about 70% of the primary field is achieved. The CTC device and scheme of high level capturing of magnetic flux are presented.

  14. Mechanical Commissioning of the ATLAS Barrel Toroid Magnet

    CERN Document Server

    Foussat, A; Dudarev, A; Bajas, H; Védrine, P; Berriaud, C; Sun, Z; Sorbi, M

    2008-01-01

    ATLAS is a general-purpose detector designed to run at the highest luminosity at the CERN Large Hadron Collider. Its features include the 4 T Barrel Toroid magnet, the largest superconducting magnet (25 m long, 20 m diameter) that provides the magnetic field for the ATLAS muon spectrometer. The coils integrated at CERN, were tested individually at maximum current of 22 kA in 2005. Following the mechanical assembly of the Barrel Toroid in the ATLAS underground cavern, the test of the full Barrel Toroid was performed in October 2006. Further tests are foreseen at the end 2007 when the system will include the two End Cap Toroids (ECT). The paper gives an overview of the good mechanical test results achieved in comparison with model predictions and the experience gained in the mechanical behavior of the ATLAS Toroidal coils is discussed.

  15. Perturbing macroscopic magnetohydrodynamic stability for toroidal plasmas

    Science.gov (United States)

    Comer, Kathryn J.

    We have introduced a new perturbative technique to rapidly explore the dependence of long wavelength ideal magnetohydrodynamic (MHD) instabilities on equilibrium profiles, shaping properties, and wall parameters. Traditionally, these relations are studied with numerical parameter scans using computationally intensive stability codes. Our perturbative technique first finds the equilibrium and stability using traditional methods. Subsequent small changes in the original equilibrium parameters change the stability. We quickly find the new stability with an expansion of the energy principle, rather than with another run of the stability codes. We first semi-analytically apply the technique to the screw pinch after eliminating compressional Alfven wave effects. The screw pinch results validate the approach, but also indicate that allowable perturbations to equilibria with certain features may be restricted. Next, we extend the approach to toroidal geometry using experimental equilibria and a simple constructed equilibrium, with the ideal MHD stability code GATO. Stability properties are successfully predicted from perturbed toroidal equilibria when only the vacuum beyond the plasma is perturbed (through wall parameter variations), rather than the plasma itself. Small plasma equilibrium perturbations to both experimental and simple equilibria result in very large errors to the predicted stability, and valid results are found only over a narrow range of most perturbations. Despite the large errors produced when changing plasma parameters, the wall perturbations revealed two useful applications of this technique. Because the calculations are non-iterative matrix multiplications, the convergence issues that can disrupt a full MHD stability code are absent. Marginal stability, therefore, is much easier to find with the perturbative technique. Also, the perturbed results can be input as the initial guess for the eigenvalue for a full stability code, and improve subsequent

  16. ATF [Advanced Toroidal Facility] data management

    International Nuclear Information System (INIS)

    Kannan, K.L.; Baylor, L.R.

    1988-01-01

    Data management for the Advanced Toroidal Facility (ATF), a stellarator located at Oak Ridge National Laboratory (ORNL), is provided by DMG, a locally developed, VAX-based software system. DMG is a data storage and retrieval software system that provides the user interface to ATF raw and analyzed data. Data are described in terms of data models and data types and are organized as signals into files, which are internally documented. The system was designed with user accessibility, software maintainability, and extensibility as primary goals. Extensibility features include compatibility with ATF as it moves from pulsed to steady-state operation and capability for use of the DMG system with experiments other than ATF. DMG is implemented as a run-time library of routines available as a shareable image. General-purpose and specialized data acquisition and analysis applications have been developed using the DMG system. This paper describes the DMG system and the interfaces to it. 4 refs., 2 figs

  17. The theory of toroidally confined plasmas

    CERN Document Server

    White, Roscoe B

    2014-01-01

    This graduate level textbook develops the theory of magnetically confined plasma, with the aim of bringing the reader to the level of current research in the field of thermonuclear fusion. It begins with the basic concepts of magnetic field description, plasma equilibria and stability, and goes on to derive the equations for guiding center particle motion in an equilibrium field. Topics include linear and nonlinear ideal and resistive modes and particle transport. It is of use to workers in the field of fusion both for its wide-ranging account of tokamak physics and as a kind of handbook or formulary. This edition has been extended in a number of ways. The material on mode-particle interactions has been reformulated and much new information added, including methodology for Monte Carlo implementation of mode destabilization. These results give explicit means of carrying out mode destabilization analysis, in particular for the dangerous fishbone mode. A new chapter on cyclotron motion in toroidal geometry has ...

  18. Isomorphic routing on a toroidal mesh

    Science.gov (United States)

    Mao, Weizhen; Nicol, David M.

    1993-01-01

    We study a routing problem that arises on SIMD parallel architectures whose communication network forms a toroidal mesh. We assume there exists a set of k message descriptors (xi, yi), where (xi, yi) indicates that the ith message's recipient is offset from its sender by xi hops in one mesh dimension, and yi hops in the other. Every processor has k messages to send, and all processors use the same set of message routing descriptors. The SIMD constraint implies that at any routing step, every processor is actively routing messages with the same descriptors as any other processor. We call this isomorphic routing. Our objective is to find the isomorphic routing schedule with least makespan. We consider a number of variations on the problem, yielding complexity results from O(k) to NP-complete. Most of our results follow after we transform the problem into a scheduling problem, where it is related to other well-known scheduling problems.

  19. Distance statistics in large toroidal maps

    Science.gov (United States)

    Guitter, E.

    2010-04-01

    We compute a number of distance-dependent universal scaling functions characterizing the distance statistics of large maps of genus one. In particular, we obtain explicitly the probability distribution for the length of the shortest non-contractible loop passing via a random point in the map, and that for the distance between two random points. Our results are derived in the context of bipartite toroidal quadrangulations, using their coding by well-labeled 1-trees, which are maps of genus one with a single face and appropriate integer vertex labels. Within this framework, the distributions above are simply obtained as scaling limits of appropriate generating functions for well-labeled 1-trees, all expressible in terms of a small number of basic scaling functions for well-labeled plane trees.

  20. Advanced toroidal facility vaccuum vessel stress analyses

    International Nuclear Information System (INIS)

    Hammonds, C.J.; Mayhall, J.A.

    1987-01-01

    The complex geometry of the Advance Toroidal Facility (ATF) vacuum vessel required special analysis techniques in investigating the structural behavior of the design. The response of a large-scale finite element model was found for transportation and operational loading. Several computer codes and systems, including the National Magnetic Fusion Energy Computer Center Cray machines, were implemented in accomplishing these analyses. The work combined complex methods that taxed the limits of both the codes and the computer systems involved. Using MSC/NASTRAN cyclic-symmetry solutions permitted using only 1/12 of the vessel geometry to mathematically analyze the entire vessel. This allowed the greater detail and accuracy demanded by the complex geometry of the vessel. Critical buckling-pressure analyses were performed with the same model. The development, results, and problems encountered in performing these analyses are described. 5 refs., 3 figs

  1. Advanced Toroidal Facility vacuum vessel stress analyses

    International Nuclear Information System (INIS)

    Hammonds, C.J.; Mayhall, J.A.

    1987-01-01

    The complex geometry of the Advanced Toroidal Facility (ATF) vacuum vessel required special analysis techniques in investigating the structural behavior of the design. The response of a large-scale finite element model was found for transportation and operational loading. Several computer codes and systems, including the National Magnetic Fusion Energy Computer Center Cray machines, were implemented in accomplishing these analyses. The work combined complex methods that taxed the limits of both the codes and the computer systems involved. Using MSC/NASTRAN cyclic-symmetry solutions permitted using only 1/12 of the vessel geometry to mathematically analyze the entire vessel. This allowed the greater detail and accuracy demanded by the complex geometry of the vessel. Critical buckling-pressure analyses were performed with the same model. The development, results, and problems encountered in performing these analyses are described

  2. Shear-dependant toroidal vortex flow

    Energy Technology Data Exchange (ETDEWEB)

    Khorasani, Nariman Ashrafi; Haghighi, Habib Karimi [Payame Noor University, Tehran (Iran, Islamic Republic of)

    2013-01-15

    Pseudoplastic circular Couette flow in annulus is investigated. The flow viscosity is dependent on the shear rate, which directly affects the conservation equations that are solved in the present study by the spectral method in the present study. The pseudoplastic model adopted here is shown to be a suitable representative of nonlinear fluids. Unlike the previous studies, where only the square of shear rate term in the viscosity expression was considered to ease the numerical manipulations, in the present study takes the term containing the quadratic power into account. The curved streamlines of the circular Couette flow can cause a centrifugal instability leading to toroidal vortices, known as Taylor vortices. It is further found that the critical Taylor number becomes lower as the pseudoplastic effect increases. Comparison with existing measurements on pseudoplastic circular Couette flow results in good agreement.

  3. Nonideal magnetohydrodynamic instabilities and toroidal magnetic confinement

    Energy Technology Data Exchange (ETDEWEB)

    Furth, H.P.

    1985-05-01

    The marked divergence of experimentally observed plasma instability phenomena from the predictions of ideal magnetohydrodynamics led in the early 1960s to the formulations of finite-resistivity stability theory. Beginning in the 1970s, advanced plasma diagnostics have served to establish a detailed correspondence between the predictions of the finite-resistivity theory and experimental plasma behavior - particularly in the case of the resistive kink mode and the tokamak plasma. Nonlinear resistive-kink phenomena have been found to govern the transport of magnetic flux and plasma energy in the reversed-field pinch. The other predicted finite-resistivity instability modes have been more difficult to identify directly and their implications for toroidal magnetic confinement are still unresolved.

  4. Design considerations for ITER toroidal field coils

    International Nuclear Information System (INIS)

    Kalsi, S.S.; Lousteau, D.C.; Miller, J.R.

    1987-01-01

    The International Thermonuclear Experimental Reactor (ITER) is a new tokamak design project with joint participation from Europe, Japan, the Union of Soviet Socialist Republics (U.S.S.R.), and the United States. This paper describes a magnetic and mechanical design methodology for toroidal field (TF) coils that employs Nb 3 Sn superconductor technology. Coil winding is sized by using conductor concepts developed for the U.S. TIBER concept. Manifold concepts are presented for the complete cooling system. Also included are concepts for the coil structural arrangement. The effects of in-plane and out-of-plane loads are included in the design considerations for the windings and case. Concepts are presented for reacting these loads with a minimum amount of additional structural material. Concepts discussed in this paper could be considered for the ITER TF coils

  5. Toroidal microinstability studies of high temperature tokamaks

    International Nuclear Information System (INIS)

    Rewoldt, G.; Tang, W.M.

    1989-07-01

    Results from comprehensive kinetic microinstability calculations are presented showing the effects of toroidicity on the ion temperature gradient mode and its relationship to the trapped-electron mode in high-temperature tokamak plasmas. The corresponding particle and energy fluxes have also been computed. It is found that, although drift-type microinstabilities persist over a wide range of values of the ion temperature gradient parameter η i ≡ (dlnT i /dr)/(dlnn i /dr), the characteristic features of the dominant mode are those of the η i -type instability when η i > η ic ∼1.2 to 1.4 and of the trapped-electron mode when η i ic . 16 refs., 7 figs

  6. Compact toroid development, activity plan for spheromaks

    International Nuclear Information System (INIS)

    1984-06-01

    This document contains the description, goals, status, plans, and approach for the investigation of the properties of a magnetic configuration for plasma confinement identified as the spheromak. This component of the magnetic fusion development program has been characterized by its potential for physical compactness and a flexible range of output power. The included material represents the second phase of spheromak program planning. The first was completed in February 1983 and was reported in DOE/ER-0160, Compact Toroid Development. This planning builds on that previous report and concentrates on the detailed plans for the next several years of the current DOE sponsored program. It has been deliberately restricted to the experimental and theoretical efforts possible within the present scale of effort. A third phase of this planning exercise will examine the subsequent effort and resources needed to achieve near-term (1987 to 1990) spheromak technical objectives

  7. Progress on large superconducting toroidal field coils

    International Nuclear Information System (INIS)

    Haubenreich, P.N.; Luton, J.N.; Thompson, P.B.; Beard, D.S.

    1979-01-01

    Large superconducting toroidal field coils of competing designs are being produced by six major industrial teams. In the US, teams headed by General Dynamics Convair, General Electric, and Westinghouse are under contract to design and fabricate one coil each to specifications established by the Large Coil Program. A facility for testing 6 coils in a toroidal array at fields to 8 to 12 tesla is under construction at Oak Ridge. Through an international agreement, EURATOM, Japan, and Switzerland will produce one coil each for testing with the US coils. Each test coil will have a 2.5 x 3.5 m D-shape winding bore and is designed to operate at a current of 10 to 18 kA at a peak field of 8T while subjected to pulsed fields of 0.14 T applied in 1.0 s. There are significant differences among the six coil designs: five use NbTi, one Nb 3 Sn; three are cooled by pool boiling helium, three by forced flow; five have welded or bolted stainless steel coil cases, one has aluminum plate structure. All are designed to be cryostable at 8T, with structural margin for extended operation. The three US coil teams are almost or completely finished with detailed design and are now procuring materials and setting up manufacturing equipment. The non-US teams are at various stages of verification testing and design. The GDC and GE coils are scheduled for delivery in the spring of 1981 and the others will be completed a year later. The 11-m diameter vessel at the test facility has been completed and major components of the test stand are being procured. Engineering and procurement to upgrade the helium liquifier-refrigerator system are under way

  8. Petascale Parallelization of the Gyrokinetic Toroidal Code

    Energy Technology Data Exchange (ETDEWEB)

    Ethier, Stephane; Adams, Mark; Carter, Jonathan; Oliker, Leonid

    2010-05-01

    The Gyrokinetic Toroidal Code (GTC) is a global, three-dimensional particle-in-cell application developed to study microturbulence in tokamak fusion devices. The global capability of GTC is unique, allowing researchers to systematically analyze important dynamics such as turbulence spreading. In this work we examine a new radial domain decomposition approach to allow scalability onto the latest generation of petascale systems. Extensive performance evaluation is conducted on three high performance computing systems: the IBM BG/P, the Cray XT4, and an Intel Xeon Cluster. Overall results show that the radial decomposition approach dramatically increases scalability, while reducing the memory footprint - allowing for fusion device simulations at an unprecedented scale. After a decade where high-end computing (HEC) was dominated by the rapid pace of improvements to processor frequencies, the performance of next-generation supercomputers is increasingly differentiated by varying interconnect designs and levels of integration. Understanding the tradeoffs of these system designs is a key step towards making effective petascale computing a reality. In this work, we examine a new parallelization scheme for the Gyrokinetic Toroidal Code (GTC) [?] micro-turbulence fusion application. Extensive scalability results and analysis are presented on three HEC systems: the IBM BlueGene/P (BG/P) at Argonne National Laboratory, the Cray XT4 at Lawrence Berkeley National Laboratory, and an Intel Xeon cluster at Lawrence Livermore National Laboratory. Overall results indicate that the new radial decomposition approach successfully attains unprecedented scalability to 131,072 BG/P cores by overcoming the memory limitations of the previous approach. The new version is well suited to utilize emerging petascale resources to access new regimes of physical phenomena.

  9. Quadrupole moments of hadrons

    International Nuclear Information System (INIS)

    Krivoruchenko, M.I.

    1985-01-01

    In chiral bag model an expression is obtained for the quark wave functions with account of color and pion interaction of quarks. The quadrupole moments of nonstrange hadrons are calculated. Quadrupole moment of nucleon isobar is found to be Q(Δ)=-6.3x10 -28 esub(Δ)(cm)sup(2). Fredictions of the chiral bag model are in strong disagreement with the non-relativistic quark model

  10. Commissioning Test of ATLAS End-Cap Toroidal Magnets

    CERN Document Server

    Dudarev, A; Foussat, A; Benoit, P; Jeckel, M; Olyunin, A; Kopeykin, N; Stepanov, V; Deront, L; Olesen, G; Ponts, X; Ravat, S; Sbrissa, K; Barth, J; Bremer, J; Delruelle, J; Metselaar, J; Pengo, R; Pirotte, O; Buskop, J; Baynham, D E; Carr, F S; Holtom, E

    2009-01-01

    The system of superconducting toroids in the ATLAS experiment at CERN consists of three magnets. The Barrel Toroid was assembled and successfully tested in 2006. Next, two End-Cap Toroids have been tested on surface at 77 K and installed in the cavern, 100-m underground. The End Cap Toroids are based on Al stabilized Nb-Ti/Cu Rutherford cables, arranged in double pancake coils and conduction cooled at 4.6 K. The nominal current is 20.5 kA at 4.1 T peak field in the windings and the stored energy is 250 MJ per toroid. Prior to final testing of the entire ATLAS Toroidal system, each End Cap Toroid passed a commissioning test up to 21 kA to guarantee a reliable performance in the final assembly. In this paper the test results are described. It includes the stages of test preparation, isolation vacuum pumping and leak testing, cooling down, step-by-step charging to full current, training quenches and quench recovery. By fast discharges the quench detection and protection system was checked to demonstrate a safe e...

  11. Spontaneous magnetization in high-density quark matter

    DEFF Research Database (Denmark)

    Tsue, Yasuhiko; da Providência, João; Providência, Constanca

    2015-01-01

    It is shown that spontaneous magnetization occurs due to the anomalous magnetic moments of quarks in high-density quark matter under the tensor-type four-point interaction. The spin polarized condensate for each flavor of quark appears at high baryon density, which leads to the spontaneous...

  12. 1D equation for toroidal momentum transport in a tokamak

    International Nuclear Information System (INIS)

    Rozhansky, V A; Senichenkov, I Yu

    2010-01-01

    A 1D equation for toroidal momentum transport is derived for a given set of turbulent transport coefficients. The averaging is performed taking account of the poloidal variation of the toroidal fluxes and is based on the ambipolar condition of the zero net radial current through the flux surface. It is demonstrated that taking account of the Pfirsch-Schlueter fluxes leads to a torque in the toroidal direction which is proportional to the gradient of the ion temperature. This effect is new and has not been discussed before. The boundary condition at the separatrix, which is based on the results of the 2D simulations of the edge plasma, is formulated.

  13. Performance of a Folded-Strip Toroidally Wound Induction Machine

    DEFF Research Database (Denmark)

    Jensen, Bogi Bech; Jack, Alan G.; Atkinson, Glynn J.

    2011-01-01

    This paper presents the measured experimental results from a four-pole toroidally wound induction machine, where the stator is constructed as a pre-wound foldable strip. It shows that if the machine is axially restricted in length, the toroidally wound induction machine can have substantially...... shorter stator end-windings than conventionally wound induction machines, and hence that a toroidally wound induction machine can have lower losses and a higher efficiency. The paper also presents the employed construction method, which emphasizes manufacturability, and highlights the advantages...

  14. Deformation energy of a toroidal nucleus and plane fragmentation barriers

    International Nuclear Information System (INIS)

    Fauchard, C.; Royer, G.

    1996-01-01

    The path leading to pumpkin-like configurations and toroidal shapes is investigated using a one-parameter shape sequence. The deformation energy is determined within the analytical expressions obtained for the various shape-dependent functions and the generalized rotating liquid drop model taking into account the proximity energy and the temperature. With increasing mass and angular momentum, a potential well appears in the toroidal shape path. For the heaviest systems, the pocket is large and locally favourable with respect to the plane fragmentation barriers which might allow the formation of evanescent toroidal systems which would rapidly decay in several fragments to minimize the surface tension. (orig.)

  15. Progress in gyrokinetic simulations of toroidal ITG turbulence

    International Nuclear Information System (INIS)

    Nevins, W.M.; Dimits, A.M.; Cohen, B.I.; Shumaker, D.E.

    2001-01-01

    The 3-D nonlinear toroidal gyrokinetic simulation code PG3EQ is used to study toroidal ion temperature gradient (ITG) driven turbulence - a key cause of the anomalous transport that limits tokamak plasma performance. Systematic studies of the dependence of ion thermal transport on various parameters and effects are presented, including dependence on E-vectorxB-vector and toroidal velocity shear, sensitivity to the force balance in simulations with radial temperature gradient variation, and the dependences on magnetic shear and ion temperature gradient. (author)

  16. Laser-induced production of large carbon-based toroids

    International Nuclear Information System (INIS)

    Lyn, M. Elizabeth; He Jibao; Koplitz, Brent

    2005-01-01

    We report on the production of large carbon-based toroids (CBTs) from fullerenes. The process involves two-step laser irradiation of a mixed fullerene target (76% C 60 , 22% C 70 ). Transmission electron microscopy (TEM) clearly identifies toroidal-shaped structures as well as Q-shaped constructs. The typical diameters of the CBTs are ∼0.2-0.3 μm with tubular diameters of ∼50-100 nm, but toroids as wide as 0.5 μm are observed making them nanostructures on the verge of being microstructures

  17. Gaseous toroid around Saturn. [Saturnian ring system for atomic hydrogen trapping in Titan atmospheric model

    Science.gov (United States)

    Mcdonough, T. R.

    1974-01-01

    The trapping of Titan's escaping atmosphere in the Saturnian system by a toroidal ring is discussed. The radius of the toroid is comparable to Titan's orbit, or about ten times larger than the visible rings. Theoretical atmospheric models are formulated that consider Saturn's gravitational attraction and magnetospheric properties in forming this toroid and in protecting toroid particles from direct ionization by solar wind particles.

  18. Tau magnetic moment

    Science.gov (United States)

    González-Sprinberg, G. A.; Vidal, J.

    2017-10-01

    The τ lepton magnetic moment theoretical predictions and measurements are reviewed. While it is believed that such a high mass particle is a good candidate to show up new physics, this is not the case up to now. The magnetic moment of elementary fermions, and in particular the anomalous magnetic moment of the electron, had an historical impact both in relativistic quantum mechanics and in quantum field theories. Besides, many new physics models were discarded when confronted with these magnitudes. More recently, the discrepancy of the experiments and the theoretical predictions for the muon anomalous magnetic moment is still an open issue. For the τ lepton, instead, while the theoretical prediction is well known for the standard model and some new physics models, the data are very far of determining even its sign or the first figure. We will discuss the most important theoretical aspects of the τ magnetic moment, and also the current accepted measurements and future perspectives, in particular related to B-factories.

  19. Influence of toroidal rotation on resistive tearing modes in tokamaks

    International Nuclear Information System (INIS)

    Wang, S.; Ma, Z. W.

    2015-01-01

    Influence of toroidal equilibrium plasma rotation on m/n = 2/1 resistive tearing modes is studied numerically using a 3D toroidal MHD code (CLT). It is found that the toroidal rotation with or without shear can suppress the tearing instability and the Coriolis effect in the toroidal geometry plays a dominant role on the rotation induced stabilization. For a high viscosity plasma (τ R /τ V  ≫ 1, where τ R and τ V represent resistive and viscous diffusion time, respectively), the effect of the rotation shear combined with the viscosity appears to be stabilizing. For a low viscosity plasmas (τ R /τ V  ≪ 1), the rotation shear shows a destabilizing effect when the rotation is large

  20. Influence of toroidal rotation on resistive tearing modes in tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S.; Ma, Z. W., E-mail: zwma@zju.edu.cn [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China)

    2015-12-15

    Influence of toroidal equilibrium plasma rotation on m/n = 2/1 resistive tearing modes is studied numerically using a 3D toroidal MHD code (CLT). It is found that the toroidal rotation with or without shear can suppress the tearing instability and the Coriolis effect in the toroidal geometry plays a dominant role on the rotation induced stabilization. For a high viscosity plasma (τ{sub R}/τ{sub V} ≫ 1, where τ{sub R} and τ{sub V} represent resistive and viscous diffusion time, respectively), the effect of the rotation shear combined with the viscosity appears to be stabilizing. For a low viscosity plasmas (τ{sub R}/τ{sub V} ≪ 1), the rotation shear shows a destabilizing effect when the rotation is large.

  1. Toroidal and rotating bubble nuclei and the nuclear fragmentation

    International Nuclear Information System (INIS)

    Royer, G.; Fauchard, C.; Haddad, F.; Jouault, B.

    1997-01-01

    The energy of rotating bubble and toroidal nuclei predicted to be formed in central heavy ion collisions at intermediate energies is calculated within the generalized rotating liquid drop model. Previously, a one-parameter shape sequence has been defined to describe the path leading to pumpkin-like configurations and toroidal shapes. New analytical expressions for the shape dependent functions have been obtained. The potential barriers standing in these exotic deformation paths are compared with the three-dimensional and plane-fragmentation barriers. Metastable bubble-like minima only appear at very high angular momentum and above the three dimensional fragmentation barriers. In the toroidal deformation path of the heaviest systems exists a large potential pocket localized below the plane-fragmentation barriers. This might allow the temporary survival of heavy nuclear toroids before the final clusterization induced by the surface and proximity tension

  2. System and method of operating toroidal magnetic confinement devices

    Science.gov (United States)

    Chance, M.S.; Jardin, S.C.; Stix, T.H.; Grimm, R.C.; Manickam, J.; Okabayashi, M.

    1984-08-30

    This invention pertains to methods and arrangements for attaining high beta values in plasma confinement devices. More specifically, this invention pertains to methods for accessing the second stability region of operation in toroidal magnetic confinement devices.

  3. Effect of toroidicity during lower hybrid mode conversion

    International Nuclear Information System (INIS)

    Riyopoulos, S.; Mahajan, S.

    1985-11-01

    The effect of toroidicity during lower hybrid mode conversion is examined by treating the wave propagation in an inhomogeneous medium as an eigenvalue problem for ω 2 (m,n),m,n poloidal and toroidal wave numbers. Since the frequency regime near ω 2 = ω/sub LH/ 2 is an accumulation point for the eigenvalue spectrum, the degenerate perturbation technique must be applied. The toroidal eigenmodes are constructed by a zeroth order superposition of monochromatic solutions with different poloidal dependence m, thus they generically exhibit a wide spectrum in k/sub parallel/ for given fixed ω 2 even for small inverse aspect ratio epsilon. In case that the average is in the neighborhood of k/sub min/, the minimum wave number for accessibility of the mode conversion regime, it is expected that excitation of toroidal modes rather than geometric optics will determine the wave coupling to the plasma

  4. Structural design of the superconducting toroidal field coils for ITER

    International Nuclear Information System (INIS)

    Wong, F.M.G.; Sborchia, C.; Thome, R.J.; Malkov, A.; Titus, P.H.

    1995-01-01

    Structural design issues and features of the superconducting toroidal field (TF) coils for the International Thermonuclear Experimental Reactor (ITER) will be discussed. Selected analyses of the structural and mechanical behavior of the ITER TF coils will also be presented. (orig.)

  5. Turbulent and neoclassical toroidal momentum transport in tokamak plasmas

    International Nuclear Information System (INIS)

    Abiteboul, J.

    2012-10-01

    The goal of magnetic confinement devices such as tokamaks is to produce energy from nuclear fusion reactions in plasmas at low densities and high temperatures. Experimentally, toroidal flows have been found to significantly improve the energy confinement, and therefore the performance of the machine. As extrinsic momentum sources will be limited in future fusion devices such as ITER, an understanding of the physics of toroidal momentum transport and the generation of intrinsic toroidal rotation in tokamaks would be an important step in order to predict the rotation profile in experiments. Among the mechanisms expected to contribute to the generation of toroidal rotation is the transport of momentum by electrostatic turbulence, which governs heat transport in tokamaks. Due to the low collisionality of the plasma, kinetic modeling is mandatory for the study of tokamak turbulence. In principle, this implies the modeling of a six-dimensional distribution function representing the density of particles in position and velocity phase-space, which can be reduced to five dimensions when considering only frequencies below the particle cyclotron frequency. This approximation, relevant for the study of turbulence in tokamaks, leads to the so-called gyrokinetic model and brings the computational cost of the model within the presently available numerical resources. In this work, we study the transport of toroidal momentum in tokamaks in the framework of the gyrokinetic model. First, we show that this reduced model is indeed capable of accurately modeling momentum transport by deriving a local conservation equation of toroidal momentum, and verifying it numerically with the gyrokinetic code GYSELA. Secondly, we show how electrostatic turbulence can break the axisymmetry and generate toroidal rotation, while a strong link between turbulent heat and momentum transport is identified, as both exhibit the same large-scale avalanche-like events. The dynamics of turbulent transport are

  6. Polymer- and salt-induced toroids of hexagonal DNA.

    OpenAIRE

    Ubbink, J; Odijk, T

    1995-01-01

    A model is proposed for polymer- and salt-induced toroidal condensates of DNA, based on a recent theory of the undulation enhancement of the electrostatic interaction in the bulk hexagonal phase of semiflexible polyions. In a continuum approximation, the thermodynamic potential of a monomolecular toroid may be split up in bulk, surface, and curvature contributions. With the help of an approximate analytical minimization procedure, the optimal torus dimensions are calculated as a function of t...

  7. Transport in the high temperature core of toroidal confinement systems

    International Nuclear Information System (INIS)

    Weiland, J.

    1994-01-01

    Recent theoretical and experimental results on confinement of hot plasmas in toroidal devices, particularly tokamaks, are discussed from general principal points of view and related to predictions from a toroidal drift wave model using a full transport matrix including off diagonal terms. A reactive fluid model corresponding to a two pole approximation of the kinetic response is used. This model has the ability to reproduce both adiabatic and isothermal limits of the perpendicular dynamics. 106 refs, 8 figs, 1 tab

  8. Moment magnitude scale

    Energy Technology Data Exchange (ETDEWEB)

    Hanks, T.C.; Kanamori, H.

    1979-05-10

    The nearly conincident forms of the relations between seismic moment M/sub o/ and the magnitudes M/sub L/, M/sub s/, and M/sub w/ imply a moment magnitude scale M=2/3 log M/sub o/-10.7 which is uniformly valid for 3< or approx. =M/sub L/< or approx. = 7, 5 < or approx. =M/sub s/< or approx. =7 1/2 and M/sub w/> or approx. = 7 1/2.

  9. An important step for the ATLAS toroid magnet

    CERN Multimedia

    2000-01-01

    The ATLAS experiment's prototype toroid coil arrives at CERN from the CEA laboratory in Saclay on 6 October. The world's largest superconducting toroid magnet is under construction for the ATLAS experiment. A nine-metre long fully functional prototype coil was delivered to CERN at the beginning of October and has since been undergoing tests in the West Area. Built mainly by companies in France and Italy under the supervision of engineers from the CEA-Saclay laboratory near Paris and Italy's INFN-LASA, the magnet is a crucial step forward in the construction of the ATLAS superconducting magnet system. Unlike any particle detector that has gone before, the ATLAS detector's magnet system consists of a large toroidal system enclosing a small central solenoid. The barrel part of the toroidal system will use eight toroid coils, each a massive 25 metres in length. These will dwarf the largest toroids in the world when ATLAS was designed, which measure about six metres. So the ATLAS collaboration decided to build a...

  10. Dynamics of accelerated compact toroidal plasmas

    International Nuclear Information System (INIS)

    McLean, H.S.; Eddleman, J.L.; Hammer, J.H.; Hartman, C.W.; Molvik, A.W.

    1990-01-01

    Previous work on the RACE experiment has demonstrated acceleration and focusing of spheromak-type compact toroids of low mass (10 μg), low density (10 13 cm -3 ), and low magnetic field (2 KG). Computer modeling and measurements give reasonably good accounting of ring mass, momentum, and energy. Present work has been toward increasing the ring magnetic field and utilizing inductive storage by compressing similar plasma rings prior to acceleration. The precompression, followed by acceleration has been performed. Ring density and magnetic field have increased (n e ∼ 10 15 cm -3 , B ∼ 4 KG) in the precompression cone, and magnetic field increases (B ∼ 8--12 KG) after compression and during acceleration, however, trajectory measurements have shown an increase in drag or possibly ring mass above that accounted for by the density measurements in the precompression cone. For the low mass/density/field rings, drag forces did not need to be invoked for agreement between modeling and experiment and mass was consistent with electron density measurements. Drag and/or mass change is now apparently important in this higher mass/density/field regime

  11. Toroidal regularization of the guiding center Lagrangian

    Science.gov (United States)

    Burby, J. W.; Ellison, C. L.

    2017-11-01

    In the Lagrangian theory of guiding center motion, an effective magnetic field B*=B +(m /e )v∥∇× b appears prominently in the equations of motion. Because the parallel component of this field can vanish, there is a range of parallel velocities where the Lagrangian guiding center equations of motion are either ill-defined or very badly behaved. Moreover, the velocity dependence of B* greatly complicates the identification of canonical variables and therefore the formulation of symplectic integrators for guiding center dynamics. This letter introduces a simple coordinate transformation that alleviates both these problems simultaneously. In the new coordinates, the Liouville volume element is equal to the toroidal contravariant component of the magnetic field. Consequently, the large-velocity singularity is completely eliminated. Moreover, passing from the new coordinate system to canonical coordinates is extremely simple, even if the magnetic field is devoid of flux surfaces. We demonstrate the utility of this approach in regularizing the guiding center Lagrangian by presenting a new and stable one-step variational integrator for guiding centers moving in arbitrary time-dependent electromagnetic fields.

  12. Compact toroid injection into C-2U

    Science.gov (United States)

    Roche, Thomas; Gota, H.; Garate, E.; Asai, T.; Matsumoto, T.; Sekiguchi, J.; Putvinski, S.; Allfrey, I.; Beall, M.; Cordero, M.; Granstedt, E.; Kinley, J.; Morehouse, M.; Sheftman, D.; Valentine, T.; Waggoner, W.; the TAE Team

    2015-11-01

    Sustainment of an advanced neutral beam-driven FRC for a period in excess of 5 ms is the primary goal of the C-2U machine at Tri Alpha Energy. In addition, a criteria for long-term global sustainment of any magnetically confined fusion reactor is particle refueling. To this end, a magnetized coaxial plasma-gun has been developed. Compact toroids (CT) are to be injected perpendicular to the axial magnetic field of C-2U. To simulate this environment, an experimental test-stand has been constructed. A transverse magnetic field of B ~ 1 kG is established (comparable to the C-2U axial field) and CTs are fired across it. As a minimal requirement, the CT must have energy density greater than that of the magnetic field it is to penetrate, i.e., 1/2 ρv2 >=B2 / 2μ0 . This criteria is easily met and indeed the CTs traverse the test-stand field. A preliminary experiment on C-2U shows the CT also capable of penetrating into FRC plasmas and refueling is observed resulting in a 20 - 30% increase in total particle number per single-pulsed CT injection. Results from test-stand and C-2U experiments will be presented.

  13. Collisionless two-fluid theory of toroidal ηi stability

    International Nuclear Information System (INIS)

    Mondt, J.; Weiland, J.

    1989-01-01

    A collisionless two-fluid theory based on a fourteen-moment generalization of the 'double-adiabatic' equations is developed to lowest order in the Larmor radius parameter, and applied to derive the toroidal η i stability boundary for all values of the ratio of the density gradient scale length divided by the field curvature length. The present model is an improvement over existing collisional two-fluid models in view of the collisionless nature of the η i instability, while retaining the advantage over kinetic theory of the practability of mode-coupling simulations. The linear stability boundary, linear growth rate and real frequency agree fairly accurately with draft-kinetic theory

  14. Neutrino magnetic moment

    International Nuclear Information System (INIS)

    Vysotsky, M.I.

    1990-03-01

    I would like to discuss the problem of a neutrino magnetic moment which is of interest since it deals with the probable time anticorrelation of the solar v flux with the Sun magnetic activity. (author). 19 refs, 2 figs, 1 tab

  15. Magnetic moments revisited

    International Nuclear Information System (INIS)

    Towner, I.S.; Khanna, F.C.

    1984-01-01

    Consideration of core polarization, isobar currents and meson-exchange processes gives a satisfactory understanding of the ground-state magnetic moments in closed-shell-plus (or minus)-one nuclei, A = 3, 15, 17, 39 and 41. Ever since the earliest days of the nuclear shell model the understanding of magnetic moments of nuclear states of supposedly simple configurations, such as doubly closed LS shells +-1 nucleon, has been a challenge for theorists. The experimental moments, which in most cases are known with extraordinary precision, show a small yet significant departure from the single-particle Schmidt values. The departure, however, is difficult to evaluate precisely since, as will be seen, it results from a sensitive cancellation between several competing corrections each of which can be as large as the observed discrepancy. This, then, is the continuing fascination of magnetic moments. In this contribution, we revisit the subjet principally to identify the role played by isobar currents, which are of much concern at this conference. But in so doing we warn quite strongly of the dangers of considering just isobar currents in isolation; equal consideration must be given to competing processes which in this context are the mundane nuclear structure effects, such as core polarization, and the more popular meson-exchange currents

  16. Multi-moment maps

    DEFF Research Database (Denmark)

    Madsen, T. B.; Swann, A.

    2012-01-01

    and third Lie algebra Betti numbers are zero. We show that these form a special class of solvable Lie groups and provide a structural characterisation. We provide many examples of multi-moment maps for different geometries and use them to describe manifolds with holonomy contained in G(2) preserved by a two...

  17. The Humanist Moment

    Science.gov (United States)

    Higgins, Chris

    2014-01-01

    In "The Humanist Moment," Chris Higgins sets out to recover a tenable, living humanism, rejecting both the version vilified by the anti-humanists and the one sentimentalized by the reactionary nostalgists. Rescuing humanism from such polemics is only the first step, as we find at least nine rival, contemporary definitions of humanism.…

  18. Projective moment invariants

    Czech Academy of Sciences Publication Activity Database

    Suk, Tomáš; Flusser, Jan

    2004-01-01

    Roč. 26, č. 10 (2004), s. 1364-1367 ISSN 0162-8828 R&D Projects: GA ČR GA201/03/0675 Institutional research plan: CEZ:AV0Z1075907 Keywords : projective transform * moment invariants * object recognition Subject RIV: JD - Computer Applications, Robotics Impact factor: 4.352, year: 2004 http://library.utia.cas.cz/prace/20040112.pdf

  19. Distributions on unbounded moment spaces and random moment sequences

    OpenAIRE

    Dette, Holger; Nagel, Jan

    2012-01-01

    In this paper we define distributions on moment spaces corresponding to measures on the real line with an unbounded support. We identify these distributions as limiting distributions of random moment vectors defined on compact moment spaces and as distributions corresponding to random spectral measures associated with the Jacobi, Laguerre and Hermite ensemble from random matrix theory. For random vectors on the unbounded moment spaces we prove a central limit theorem where the centering vecto...

  20. Physics models in the toroidal transport code PROCTR

    Energy Technology Data Exchange (ETDEWEB)

    Howe, H.C.

    1990-08-01

    The physics models that are contained in the toroidal transport code PROCTR are described in detail. Time- and space-dependent models are included for the plasma hydrogenic-ion, helium, and impurity densities, the electron and ion temperatures, the toroidal rotation velocity, and the toroidal current profile. Time- and depth-dependent models for the trapped and mobile hydrogenic particle concentrations in the wall and a time-dependent point model for the number of particles in the limiter are also included. Time-dependent models for neutral particle transport, neutral beam deposition and thermalization, fusion heating, impurity radiation, pellet injection, and the radial electric potential are included and recalculated periodically as the time-dependent models evolve. The plasma solution is obtained either in simple flux coordinates, where the radial shift of each elliptical, toroidal flux surface is included to maintain an approximate pressure equilibrium, or in general three-dimensional torsatron coordinates represented by series of helical harmonics. The detailed coupling of the plasma, scrape-off layer, limiter, and wall models through the neutral transport model makes PROCTR especially suited for modeling of recycling and particle control in toroidal plasmas. The model may also be used in a steady-state profile analysis mode for studying energy and particle balances starting with measured plasma profiles.

  1. Toroidal Plasma Thruster for Interplanetary and Interstellar Space Flights

    International Nuclear Information System (INIS)

    Gorelenkov, N.N.; Zakharov, L.E.; Gorelenkova, M.V.

    2001-01-01

    This work involves a conceptual assessment for using the toroidal fusion reactor for deep space interplanetary and interstellar missions. Toroidal thermonuclear fusion reactors, such as tokamaks and stellarators, are unique for space propulsion, allowing for a design with the magnetic configuration localized inside toroidal magnetic field coils. Plasma energetic ions, including charged fusion products, can escape such a closed configuration at certain conditions, a result of the vertical drift in toroidal rippled magnetic field. Escaping particles can be used for direct propulsion (since toroidal drift is directed one way vertically) or to create and heat externally confined plasma, so that the latter can be used for propulsion. Deuterium-tritium fusion neutrons with an energy of 14.1 MeV also can be used for direct propulsion. A special design allows neutrons to escape the shield and the blanket of the tokamak. This provides a direct (partial) conversion of the fusion energy into the directed motion of the propellant. In contrast to other fusion concepts proposed for space propulsion, this concept utilizes the natural drift motion of charged particles out of the closed magnetic field configuration

  2. Structural analysis of TFTR toroidal field coil conceptual design

    International Nuclear Information System (INIS)

    Smith, R.A.

    1975-10-01

    The conceptual design evaluation of the V-shaped toroidal field coils on the Tokamak Fusion Test Reactor has been performed by detailed structural analysis with the finite element method. The innovation provided by this design and verified in this work is the capability to support toroidal field loads while simultaneously performing the function of twist restraint against the device axial torques resulting from the vertical field loads. The evaluations made for the conceptual design provide predictions for coil deflections and stresses. The results are available for the separate effects from toroidal fields, poloidal fields, and the thermal expansion of the coils as well as for the superposition of the primary loads and the primary plus thermal loads

  3. Vlasov tokamak equilibria with sheared toroidal flow and anisotropic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Kuiroukidis, Ap, E-mail: kouirouki@astro.auth.gr [Technological Education Institute of Serres, 62124 Serres (Greece); Throumoulopoulos, G. N., E-mail: gthroum@uoi.gr [Department of Physics, University of Ioannina, GR 451 10 Ioannina (Greece); Tasso, H., E-mail: het@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik, D-85748 Garching (Germany)

    2015-08-15

    By choosing appropriate deformed Maxwellian ion and electron distribution functions depending on the two particle constants of motion, i.e., the energy and toroidal angular momentum, we reduce the Vlasov axisymmetric equilibrium problem for quasineutral plasmas to a transcendental Grad-Shafranov-like equation. This equation is then solved numerically under the Dirichlet boundary condition for an analytically prescribed boundary possessing a lower X-point to construct tokamak equilibria with toroidal sheared ion flow and anisotropic pressure. Depending on the deformation of the distribution functions, these steady states can have toroidal current densities either peaked on the magnetic axis or hollow. These two kinds of equilibria may be regarded as a bifurcation in connection with symmetry properties of the distribution functions on the magnetic axis.

  4. Modal analysis of a stiffened toroidal shell sector

    International Nuclear Information System (INIS)

    Cerreta, R.; Di Pietro, E.; Pizzuto, A.

    1987-01-01

    This paper presents the results of the modal analysis of a sector of the toroidal vacuum vessel of a new experimental machine for research in the field of controlled thermonuclear fusion (FTU - Frascati Tokamak Upgrade). The vacuum vessel, one of the most critical components of the experimental device, consist of 12 stainless steel toroidal sectors, and it is designed to withstand pulsed electromagnetic loads during operation. Results of the modal analysis of the stiffened toroidal shell sector are compared and discussed with regard to the experimental data. Theoretical eigenvalues and eigenvectors have been predicted by means of ABAQUS finite element code. Experimental analysis has been carried out on a full scale model and natural frequencies have been measured. Satisfactory agreement between experimental and theoretical eigenvalues has been found

  5. Toroidal Superheavy Nuclei in Skyrme-Hartree-Fock Approach

    International Nuclear Information System (INIS)

    Staszczak, A.; Wong, Cheuk-Yin

    2009-01-01

    Within the self-consistent constraint Skyrme-Hartree-Fock+BCS model (SHF+BCS), we found equilibrium toroidal nuclear density distributions in the region of superheavy elements. For nuclei with a sufficient oblate deformation (Q 20 < -200 b), it becomes energetically favorable to change the genus of nuclear surface from 0 to 1, i.e., to switch the shape from a biconcave disc to a torus. The energy of the toroidal (genus=1) SHF+BCS solution relative to the compact (genus=0) ground state energy is strongly dependent both on the atomic number Z and the mass number A. We discuss the region of Z and A where the toroidal SHF+BCS total energy begins to be a global minimum

  6. Linear wave propagation in a hot axisymmetric toroidal plasma

    Energy Technology Data Exchange (ETDEWEB)

    Jaun, A. [Ecole Polytechnique Federale, Lausanne (Switzerland). Centre de Recherche en Physique des Plasma (CRPP)

    1995-03-01

    Kinetic effects on the propagation of the Alfven wave are studied for the first time in a toroidal plasma relevant for experiments. This requires the resolution of a set of coupled partial differential equations whose coefficients depend locally on the plasma parameters. For this purpose, a numerical wave propagation code called PENN has been developed using either a bilinear or a bicubic Hermite finite element discretization. It solves Maxwell`s equations in toroidal geometry, with a dielectric tensor operator that takes into account the linear response of the plasma. Two different models have been implemented and can be used comparatively to describe the same physical case: the first treats the plasma as resistive fluids and gives results which are in good agreement with toroidal fluid codes. The second is a kinetic model and takes into account the finite size of the Larmor radii; it has successfully been tested against a kinetic plasma model in cylindrical geometry. New results have been obtained when studying kinetic effects in toroidal geometry. Two different conversion mechanisms to the kinetic Alfven wave have been described: one occurs at toroidally coupled resonant surfaces and is the kinetic counterpart of the fluid models` resonance absorption. The other has no such correspondence and results directly from the toroidal coupling between the kinetic Alfven wave and the global wavefield. An analysis of a heating scenario suggests that it might be difficult to heat a plasma with Alfven waves up to temperatures that are relevant for a tokamak reactor. Kinetic effects are studied for three types of global Alfven modes (GAE, TAE, BAE) and a new class of kinetic eigenmodes is described which appear inside the fluid gap: it could be related to recent observations in the JET (Joint European Torus) tokamak. (author) 56 figs., 6 tabs., 58 refs.

  7. Face recognition using Krawtchouk moment

    Indian Academy of Sciences (India)

    Abstract. Feature extraction is one of the important tasks in face recognition. Moments are widely used feature extractor due to their superior discriminatory power and geometrical invariance. Moments generally capture the global features of the image. This paper proposes Krawtchouk moment for feature extraction in face ...

  8. Face recognition using Krawtchouk moment

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... Feature extraction is one of the important tasks in face recognition. Moments are widely used feature extractor due to their superior discriminatory power and geometrical invariance. Moments generally capture the global features of the image. This paper proposes Krawtchouk moment for feature extraction ...

  9. Paul Callaghan luminous moments

    CERN Document Server

    Callaghan, Paul

    2013-01-01

    Acknowledged internationally for his ground-breaking scientific research in the field of magnetic resonance, Sir Paul Callaghan was a scientist and visionary with a rare gift for promoting science to a wide audience. He was named New Zealander of the Year in 2011. His death in early 2012 robbed New Zealand of an inspirational leader. Paul Callaghan: Luminous Moments brings together some of his most significant writing. Whether he describes his childhood in Wanganui, reflects on discovering the beauty of science, sets out New Zealand's future potential or discusses the experience of fa

  10. Induction Motor with Switchable Number of Poles and Toroidal Winding

    Directory of Open Access Journals (Sweden)

    MUNTEANU, A.

    2011-05-01

    Full Text Available This paper presents a study of an induction motor provided with toroidal stator winding. The ring-type coils offer a higher versatility in obtaining a different number of pole pairs by means of delta/star and series/parallel connections respectively. As consequence, the developed torque can vary within large limits and the motor can be utilized for applications that require, for example, high load torque values for a short time. The study involves experimental tests and FEM simulation for an induction machine with three configurations of pole pairs. The conclusions attest the superiority of the toroidal winding for certain applications such as electric vehicles or lifting machines.

  11. On the longitudinal coupling impedance of a toroidal beam tube

    International Nuclear Information System (INIS)

    Hahn, H.; Tepikian, S.

    1990-01-01

    In this paper, the longitudinal coupling impedance of a smooth toroidal beam tube is derived. By treating the torus as a slow-wave structure, the well-known method of describing the impedance in terms of cavity resonances can be used. A simple analytical expression for the coupling impedance of a toroidal beam tube with square cross section valid in the low-frequency limit is obtained. The results from the present study are compared with previously published solutions and qualitative differences are pointed out. 16 refs., 3 figs., 1 tab

  12. Tokamak configuration analysis with the method of toroidal multipoles

    International Nuclear Information System (INIS)

    Micozzi, P.; Alladio, F.; Crisanti, F.; Marinucci, M.; Tanga, A.

    1989-01-01

    In the study of tokamak machines able to sustain plasmas of thermonuclear interest (JIT, IGNITOR, NET, CIT, ET), there is a strong quest for engineering optimization of the circuital components close to the plasma. We have developed a semianalytical axisymmetric MHD equilibrium code based on the technique of the poloidal ψ flux function expansion in toroidal harmonic series. This code is able to optimize the necessary currents in the poloidal circuits in order to sustain a plasma of fixed shape (also x-point configuration), toroidal current and poloidal β. (author) 4 refs., 4 figs

  13. Development and verification of printed circuit board toroidal transformer model

    DEFF Research Database (Denmark)

    Pejtersen, Jens; Mønster, Jakob Døllner; Knott, Arnold

    2013-01-01

    by comparing calculated parameters with 3D finite element simulations and experimental measurement results. The developed transformer model shows good agreement with the simulated and measured results. The model can be used to predict the parameters of printed circuit board toroidal transformer configurations......An analytical model of an air core printed circuit board embedded toroidal transformer configuration is presented. The transformer has been developed for galvanic isolation of very high frequency switch-mode dc-dc power converter applications. The theoretical model is developed and verified...

  14. Heat removal in INTOR via a toroidal limiter

    International Nuclear Information System (INIS)

    Mioduszewski, P.

    1981-01-01

    In the present paper the potential of removing about 100 MW of thermal plasma power via a toroidal limiter in INTOR is studied. The heat flux distributions on various limiter configurations are calculated and the thermal response of a graphite tile limiter is estimated on the base of a one-dimensional heat conduction approach. The evaporation rates which have to be expected for the given energy flux densities and radiation cooled graphite tiles are evaluated. According to the present understanding it should be possible to remove 100 MW power from the INTOR plasma via a radiation cooled toroidal limiter. (author)

  15. Neoclassical diffusion in toroidal three-cut magnetic field

    International Nuclear Information System (INIS)

    Nemov, V.V.; Shishkin, A.A.

    1975-01-01

    Quasi-classical diffusion is investigated in the regime of toroidal drift of 'bananas' in a three cut magnetic field. Unlike previous papers, it is supposed that the inhomogeneity of a helical magnetic field epsilonsub(k) is of the same order or less than that of the toroidal inhomogeneity epsilonsub(t). The case is considered when the efficient frequency of particle collisions exceeds that of the 'banana' precession around the magnetic axis. Expressions for diffusion flows and coefficients are obtained that transform into available ones at epsilonsub(h) > > epsilonsub(t) [ru

  16. A direct calculation of current drive in toroidal geometry

    International Nuclear Information System (INIS)

    Wright, J.C.; Phillips, C.K.; Bonoli, P.T.

    1998-01-01

    The magnitude and radial profiles of noninductive currents driven by fast magnetosonic waves in tokamaks have been calculated directly from the wave-induced quasilinear flux in a toroidal geometry and a Green's function for the current. An expression for the quasilinear flux has been derived which accounts for coupling between modes in the spectrum of waves launched from the antenna. A Fokker-Planck code for the Green's function and a full wave code for the electric field in the quasilinear flux are used to evaluate the current in a specified toroidal geometry

  17. Current drive by asymmetrical heating in a toroidal plasma

    International Nuclear Information System (INIS)

    Gahl, J.M.

    1986-01-01

    This report describes the first experimental observation of current generation by asymmetrical heating of ions. A unidirectional fast Alfven wave launched by a slow-wave antenna inside the Texas Tech Tokamak, asymmetrically heated the ions. Measurements of the asymmetry of the toroidal plasma current with probes at the top and bottom of the toroidal plasma column confirmed the current generation indirectly. Current generation, obtained in a one-species, hydrogen plasma, is a phenomenon which had not been predicted previously. Calculations of the dispersion relation for the fast Alfven wave near the fundamental cyclotron resonance in a one-species, hydrogen plasma, using warm plasma theory, support the experimental results

  18. Initial temperature profiles of the PDX inner toroidal limiter

    International Nuclear Information System (INIS)

    Ulrickson, M.; Kugel, H.W.

    1983-01-01

    The temperature profiles resulting from plasma operation on the PDX vertical, large area, inner toroidal limiter have been measured during both ohmic and neutral beam heated discharges using a scanning infrared camera. An asymmetric double peaked temperature profile is seen after neutral beam heated discharges. Disruptions in ohmically heated discharges are found to be preceded by a single peaked deposition and succeeded by a initially symmetric double peaked deposition. The results were compared with the Schmidt model for scrapeoff at a toroidal limiter and it was found that the measured double peaked temperature profiles yielded scrape-off lengths consistent with previous measurements

  19. Effects of 3D magnetic perturbations on toroidal plasmas

    International Nuclear Information System (INIS)

    Callen, J.D.

    2011-01-01

    Small three-dimensional (3D) magnetic field perturbations have many interesting and possibly useful effects on tokamak and quasi-symmetric stellarator plasmas. Plasma transport equations that include these effects, most notably on diamagnetic-level toroidal plasma flows, have recently been developed. The 3D field perturbations and their plasma effects can be classified according to their toroidal mode number n: low n (say 1-5) resonant (with field line pitch, q = m/n) and non-resonant fields, medium n (∼20, due to toroidal field ripple) and high n (due to microturbulence). Low n non-resonant fields induce a neoclassical toroidal viscosity (NTV) that damps toroidal rotation throughout the plasma towards an offset rotation in the counter-current direction. Recent tokamak experiments have generally confirmed and exploited these predictions by applying external low n non-resonant magnetic perturbations. Medium n toroidal field ripple produces similar effects plus possible ripple-trapping NTV effects and ion direct losses in the edge. A low n (e.g. n = 1) resonant field is mostly shielded by the toroidally rotating plasma at and inside the resonant (rational) surface. If it is large enough it can stop plasma rotation at the rational surface, facilitate magnetic reconnection there and lead to a growing stationary magnetic island (locked mode), which often causes a plasma disruption. Externally applied 3D magnetic perturbations usually have many components. In the plasma their lowest n (e.g. n = 1) externally resonant components can be amplified by kink-type plasma responses, particularly at high β. Low n plasma instabilities (e.g. resistive wall modes, neoclassical tearing modes) cause additional 3D magnetic perturbations in tokamak plasmas. Tearing modes in their nonlinear (Rutherford) regime bifurcate the topology and form magnetic islands. Finally, multiple resonant magnetic perturbations (RMPs) can, if not shielded by plasma rotation effects, cause local magnetic

  20. Electron diamagnetism and toroidal coupling of tearing modes

    International Nuclear Information System (INIS)

    Cowley, S.C.; Hastie, R.J.

    1987-10-01

    Using a simple model for the layer of the tearing mode, we demonstrate that toroidally coupled tearing modes with two rational surfaces are most unstable when the ω*'s of the electrons at the rational surfaces are equal. The onset of instability may then occur because of the tuning of ω* rather than the passage of Δ'-like quantities through zero. This mechanism for the onset of instability is sharp since the resonance is narrow. The effect of toroidal rotation is also discussed. 7 refs., 2 figs

  1. Compression of toroidal plasma by imploding plasma-liner

    International Nuclear Information System (INIS)

    Ikuta, Kazunari.

    1979-07-01

    A new concept of compressing a plasma in a closed magnetic configuration by a version of liner implosion flux compression technique is considered. The liner consists of a dense plasma cylinder, i.e. the plasma-liner. Maximum compression ratio of toroidal plasma is determined just by the initial density ratio of the toroidal plasma to the liner plasma because of the Rayleigh-Taylor instability. A start-up senario of plasma-liner is also proposed with a possible application of this concept to the creation of a burning plasma in reversed field configurations, i.e. burning plasma vortex. (author)

  2. Transient eddy currents on finite plane and toroidal conducting surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Weissenburger, D.W.; Christensen, U.R.

    1979-04-01

    this report applies a previously presented mesh analysis method to calculate transient eddy currents in conducting surfaces. Example calculations are presented for a planar conducting sheet of finite dimensions and also for a toroidal conducting surface which represents the vacuum vessel of the TFTR. For the toroidal sheet, branch inductances are initially calculated by num erically integrating the vector potential function, then the branch matrix is transformed into a mesh matrix. For the flat sheet, an analytic expression is given which enables direct calculation of the mesh inductance matrix. Streamline plots of the eddy current distributions are shown at successive time steps for each example.

  3. The forming of a superconductor cable during the winding of a large toroidal field coil

    International Nuclear Information System (INIS)

    Messemer, G.; Zehlein, H.

    1984-01-01

    The feasible range for the tension force which acts on a superconductor cable during the winding of a large D-shaped toroidal field coil depends strongly on the mechanical properties of the cable, on the geometry of the winding pack and on the arrangement of the equipment. The upper limit is imposed by possible damage within the cable. The lower limit is set by the need to assure enough compaction and to overcome the friction forces between the layers. Within this 'corridor' optimal control of elastic prestresses is desirable: this may be chosen with regard to the residual stresses and/or the elastic springback after removal of the coil former. This paper presents a simplified elastica conductor model built by a finite chain of intervals with constant bending moment and curvature. This paper describes the discrete model as well as the iterative shooting method, which finds the equilibrium shape of the conductor. The distributions of bending moment and shear forces around the D-shaped contour, as well as along the conductor, are given. Desirable improvements are outlined. In particular, the possibility of mitigating the stress concentration effect by supporting rollers suitably placed along the 'free' conductor near the bobbin is discussed. (author)

  4. Effects of Toroidal Rotation Sshear on Toroidicity-induced Alfven Eigenmodes in the National Spherical Torus Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Podesta, M; Fredrickson, E D; Gorelenkov, N N; LeBlanc, B P; Heidbrink, W W; Crocker, N A; Kubota, S

    2010-08-19

    The effects of a sheared toroidal rotation on the dynamics of bursting Toroidicity-induced Alfven eigenmodes are investigated in neutral beam heated plasmas on the National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 40 557 (2000)]. The modes have a global character, extending over most of the minor radius. A toroidal rotation shear layer is measured at the location of maximum drive for the modes. Contrary to results from other devices, no clear evidence of increased damping is found. Instead, experiments with simultaneous neutral beam and radio-frequency auxiliary heating show a strong correlation between the dynamics of the modes and the instability drive. It is argued that kinetic effects involving changes in the mode drive and damping mechanisms other than rotation shear, such as continuum damping, are mostly responsible for the bursting dynamics of the modes.

  5. Effects of Toroidal Rotation Shear on Toroidicity-induced Alfven Eigenmodes in the National Spherical Torus Experiment

    International Nuclear Information System (INIS)

    Podesta, M.; Bell, R.E.; Fredrickson, E.D.; Gorelenkov, N.N.; LeBlanc, B.P.; Heidbrink, W.W.; Crocker, N.A.; Kubota, S.; Yuh, H.

    2010-01-01

    The effects of a sheared toroidal rotation on the dynamics of bursting Toroidicity-induced Alfven eigenmodes are investigated in neutral beam heated plasmas on the National Spherical Torus Experiment (NSTX) (M. Ono et al., Nucl. Fusion 40 557 (2000)). The modes have a global character, extending over most of the minor radius. A toroidal rotation shear layer is measured at the location of maximum drive for the modes. Contrary to results from other devices, no clear evidence of increased damping is found. Instead, experiments with simultaneous neutral beam and radio-frequency auxiliary heating show a strong correlation between the dynamics of the modes and the instability drive. It is argued that kinetic effects involving changes in the mode drive and damping mechanisms other than rotation shear, such as continuum damping, are mostly responsible for the bursting dynamics of the modes.

  6. Transport and Dynamics in Toroidal Fusion Systems

    International Nuclear Information System (INIS)

    Sovinec, Carl

    2016-01-01

    The study entitled, 'Transport and Dynamics in Toroidal Fusion Systems,' (TDTFS) applied analytical theory and numerical computation to investigate topics of importance to confining plasma, the fourth state of matter, with magnetic fields. A central focus of the work is how non-thermal components of the ion particle distribution affect the 'sawtooth' collective oscillation in the core of the tokamak magnetic configuration. Previous experimental and analytical research had shown and described how the oscillation frequency decreases and amplitude increases, leading to 'monster' or 'giant' sawteeth, when the non-thermal component is increased by injecting particle beams or by exciting ions with imposed electromagnetic waves. The TDTFS study applied numerical computation to self-consistently simulate the interaction between macroscopic collective plasma dynamics and the non-thermal particles. The modeling used the NIMROD code [Sovinec, Glasser, Gianakon, et al., J. Comput. Phys. 195, 355 (2004)] with the energetic component represented by simulation particles [Kim, Parker, Sovinec, and the NIMROD Team, Comput. Phys. Commun. 164, 448 (2004)]. The computations found decreasing growth rates for the instability that drives the oscillations, but they were ultimately limited from achieving experimentally relevant parameters due to computational practicalities. Nonetheless, this effort provided valuable lessons for integrated simulation of macroscopic plasma dynamics. It also motivated an investigation of the applicability of fluid-based modeling to the ion temperature gradient instability, leading to the journal publication [Schnack, Cheng, Barnes, and Parker, Phys. Plasmas 20, 062106 (2013)]. Apart from the tokamak-specific topics, the TDTFS study also addressed topics in the basic physics of magnetized plasma and in the dynamics of the reversed-field pinch (RFP) configuration. The basic physics work contributed to a study of two

  7. Transport and Dynamics in Toroidal Fusion Systems

    Energy Technology Data Exchange (ETDEWEB)

    Sovinec, Carl [Univ. of Wisconsin, Madison, WI (United States)

    2016-09-07

    The study entitled, "Transport and Dynamics in Toroidal Fusion Systems," (TDTFS) applied analytical theory and numerical computation to investigate topics of importance to confining plasma, the fourth state of matter, with magnetic fields. A central focus of the work is how non-thermal components of the ion particle distribution affect the "sawtooth" collective oscillation in the core of the tokamak magnetic configuration. Previous experimental and analytical research had shown and described how the oscillation frequency decreases and amplitude increases, leading to "monster" or "giant" sawteeth, when the non-thermal component is increased by injecting particle beams or by exciting ions with imposed electromagnetic waves. The TDTFS study applied numerical computation to self-consistently simulate the interaction between macroscopic collective plasma dynamics and the non-thermal particles. The modeling used the NIMROD code [Sovinec, Glasser, Gianakon, et al., J. Comput. Phys. 195, 355 (2004)] with the energetic component represented by simulation particles [Kim, Parker, Sovinec, and the NIMROD Team, Comput. Phys. Commun. 164, 448 (2004)]. The computations found decreasing growth rates for the instability that drives the oscillations, but they were ultimately limited from achieving experimentally relevant parameters due to computational practicalities. Nonetheless, this effort provided valuable lessons for integrated simulation of macroscopic plasma dynamics. It also motivated an investigation of the applicability of fluid-based modeling to the ion temperature gradient instability, leading to the journal publication [Schnack, Cheng, Barnes, and Parker, Phys. Plasmas 20, 062106 (2013)]. Apart from the tokamak-specific topics, the TDTFS study also addressed topics in the basic physics of magnetized plasma and in the dynamics of the reversed-field pinch (RFP) configuration. The basic physics work contributed to a study of two-fluid effects on interchange dynamics, where

  8. The Superconducting Toroid for the New International AXion Observatory (IAXO)

    CERN Document Server

    Shilon, I.; Silva, H.; Wagner, U.; ten Kate, H.H.J.

    2013-01-01

    IAXO, the new International AXion Observatory, will feature the most ambitious detector for solar axions to date. Axions are hypothetical particles which were postulated to solve one of the puzzles arising in the standard model of particle physics, namely the strong CP (Charge conjugation and Parity) problem. This detector aims at achieving a sensitivity to the coupling between axions and photons of one order of magnitude beyond the limits of the current detector, the CERN Axion Solar Telescope (CAST). The IAXO detector relies on a high-magnetic field distributed over a very large volume to convert solar axions to detectable X-ray photons. Inspired by the ATLAS barrel and end-cap toroids, a large superconducting toroid is being designed. The toroid comprises eight, one meter wide and twenty one meters long racetrack coils. The assembled toroid is sized 5.2 m in diameter and 25 m in length and its mass is about 250 tons. The useful field in the bores is 2.5 T while the peak magnetic field in the windings is 5....

  9. Toroidal and poloidal momentum transport studies in Tokamaks

    DEFF Research Database (Denmark)

    Tala, T.; Andrew, Y.; Giroud, C.

    2007-01-01

    The present status of understanding of toroidal and poloidal momentum transport in tokamaks is presented in this paper. Similar energy confinement and momentum confinement times, i.e. τE/τφ ≈ 1 have been reported on several tokamaks. It is more important though, to study the local transport both ...

  10. Toroidal and poloidal momentum transport studies in JET

    DEFF Research Database (Denmark)

    Tala, T.; Andrew, Y.; Crombe, K.

    2007-01-01

    This paper reports on the recent studies of toroidal and poloidal momentum transport in JET. The ratio of the global energy confinement time to the momentum confinement is found to be close to tau(E)/tau(phi) = 1 except for the low density or low collisionality discharges where the ratio is tau(E...

  11. Toroidal bubbles with circulation in ideal hydrodynamics: A variational approach

    DEFF Research Database (Denmark)

    Ruban, V.P.; Juul Rasmussen, J.

    2003-01-01

    Incompressible, inviscid, irrotational, unsteady flows with circulation Gamma around a distorted toroidal bubble are considered. A general variational principle that determines the evolution of the bubble shape is formulated. For a two-dimensional (2D) cavity with a constant area A, exact...

  12. Preparing an ATLAS toroid magnet end-cap for lowering

    CERN Multimedia

    Claudia Marcelloni

    2007-01-01

    One of the two 13-m high toroid magnet end-caps for the ATLAS experiment being transported from the construction hall to the experimental area. The end-cap will be lowered into the ATLAS cavern and attached to an end of the detector.

  13. First ATLAS Barrel Toroid coil casing arrives at CERN

    CERN Multimedia

    2002-01-01

    The first of eight 25-metre long coil casings for the ATLAS experiment's barrel toroid magnet system arrived at CERN on Saturday 2 March by road from Heidelberg. This structure will be part of the largest superconducting toroid magnet ever made.   The first coil casing for the toroidal magnets of Atlas arrives at Building 180. This is the start of an enormous three-dimensional jigsaw puzzle. Each of the eight sets of double pancake coils will be housed inside aluminium coil casings, which in turn will be held inside a stainless steel vacuum vessel. A huge construction, the casing that arrived at CERN measures 25 metres in length and 5 metres in width. It weighs 20 tones. And this is just the beginning of the toroid jigsaw: by early April a batch of four double pancake coils, which altogether weighs 65 tones, will arrive from Ansaldo in Italy. The first vacuum vessel will also be arriving from Felguera in Spain this month. It will take about two years for all these 25 m long structures of casings, coils a...

  14. The problem of evolution of toroidal plasma equilibrium

    International Nuclear Information System (INIS)

    Kostomarov, D.; Zaitsev, F.; Shishkin, A.

    1999-03-01

    This paper is devoted to an advanced mathematical model for a self-consistent description of the evolution of free boundary toroidal plasmas, with a description of numerical algorithms for the solution of the appropriate non-linear system of integro-differential equations, and discussion of some results from the model. (author)

  15. Barrel Toroid fully charged to nominal field, and it works!

    CERN Multimedia

    Herman ten Kate

    After a few weeks of testing up to intermediate currents, finally, on Thursday evening November 9, the current in the Barrel Toroid was pushed up to its nominal value of 20500 A and even 500 A beyond this value to prove that we have some margin. It went surprisingly well. Of course, the 8 coils forming the toroid were already tested individually at the surface but still, some surprise may have come from those parts added to the toroid in the cavern for the first time like the 8 cryoring sections linking the coils as well as the valve box at the bottom in sector 13 regulating the helium flow or the current lead cryostat on the top in sector 5. No training quenches, nothing to worry about, and the test was concluded with a fast dump triggered at 00:40 in the very early morning of November 10. (left) The toroid current during the evening and night of November 9. (right) The test crew oscillated between fear and hope while looking at the control panels as the current approached 21kA. Big relief was in the...

  16. Low-frequency fluctuations in a pure toroidal magnetized plasma

    Indian Academy of Sciences (India)

    Xenon, krypton and argon plasmas are formed at a fixed toroidal magnetic field of 0.024 T, with a peak density of ~1011 cm−3, ~4 × 1010 cm −3 and ~2 × 1010 cm −3 respectively. The experimental investiga- tion of time-averaged plasma parameter reveals that their profiles remain insensitive to ion mass and suggests that ...

  17. Construction and initial operation of the Advanced Toroidal Facility

    Energy Technology Data Exchange (ETDEWEB)

    Lyon, J.F.; Bigelow, T.S.; Colchin, R.J.; Crume, E.C.; Dunlop, J.L.; England, A.C.; Glowienka, J.C.; Goulding, R.H.; Harris, J.H.; Hills, D.L.; Hiroe, S.; Horton, L.D.; Howe, H.C.; Isler, R.C.; Jernigan, T.C.; Langley, R.A.; Menon, M.M.; Mioduszewski, P.K.; Murakami, M.; Neilson, G.H.; Rasmussen, D.A.; Rome, J.A.; Saltmarsh, M.J.; White, T.L.; Wilgen, J.B.; Wing, W.R. (Oak Ridge National Lab., TN (USA)); Bell, G.L. (Auburn Univ., AL (USA)); Bell, J.D.; Morris, R.N.; Whitson, J.C. (Martin Marietta Energy Systems, Inc., Computing and Telecommunications Div., Oak Ridge, TN (US)); Benson, R.D.; Chipley, K.K.; Cole, M.J.; Johnson, R.L.; Nelson, B.E.; Thompson, P.B.; White, J.A. (Martin Marietta Energy Systems, Inc., Engineering Div., Oak Ridge, TN (US)); Wade, M.R. (Georgia Inst. of Tech., Atlanta, GA (USA))

    1990-01-01

    The Advanced Toroidal Facility (ATF) torsatron was designed on a physics basis for access to the second stability regime and on an engineering basis for independent fabrication of high-accuracy components. The actual construction, assembly, and initial operation of ATF are compared with the characteristics expected during the design phase.

  18. Evidence of Inward Toroidal Momentum Convection in the JET Tokamak

    DEFF Research Database (Denmark)

    Tala, T.; Zastrow, K.-D.; Ferreira, J.

    2009-01-01

    Experiments have been carried out on the Joint European Torus tokamak to determine the diffusive and convective momentum transport. Torque, injected by neutral beams, was modulated to create a periodic perturbation in the toroidal rotation velocity. Novel transport analysis shows the magnitude an...

  19. Feedback control of resistive wall modes in toroidal devices

    International Nuclear Information System (INIS)

    Liu, Y.Q.

    2002-01-01

    Active feedback of resistive wall modes is investigated using cylindrical theory and toroidal calculations. For tokamaks, good performance is obtained by using active coils with one set of coils in the poloidal direction and sensors detecting the poloidal field inside the first wall, located at the outboard mid-plane. With suitable width of the feedback coil such a system can give robust control with respect to variations in plasma current, pressure and rotation. Calculations are shown for ITER-like geometry with a double wall. The voltages and currents in the active coils are well within the design limits for ITER. Calculations for RFP's are presented for a finite number of coils both in the poloidal and toroidal directions. With 4 coils in the poloidal and 24 coils in the toroidal direction, all non-resonant modes can be stabilized both at high and low theta. Several types of sensors, including radial and internal poloidal or toroidal sensors, can stabilize the RWM, but poloidal sensors give the most robust performance. (author)

  20. Theoretical studies of non inductive current drive in compact toroids

    NARCIS (Netherlands)

    Farengo, R; Lifschitz, AF; Caputi, KI; Arista, NR; Clemente, RA

    Three non inductive current drive methods that can be applied to compact toroids axe studied. The use of neutral beams to drive current in field reversed configurations and spheromaks is studied using a Monte Carlo code that includes a complete ionization package and follows the exact particle

  1. Toroidal and poloidal momentum transport studies in tokamaks

    DEFF Research Database (Denmark)

    Tala, T.; Crombé, K.; Vries, P.C. de

    2007-01-01

    The present status of understanding of toroidal and poloidal momentum transport in tokamaks is presented in this paper. Similar energy confinement and momentum confinement times, i.e. τE/τφ ≈ 1 have been reported on several tokamaks. It is more important though, to study the local transport both ...

  2. Calculation of quasispherical liner compression in a compact toroid

    International Nuclear Information System (INIS)

    Belikov, V.V.; Goloviznin, V.M.; Kurtmullaev, R.Kh.; Semenov, V.N.

    This work considers the evolution of a compact toroid as the volume and shape of the cavity changes, all the way up to the values of the degree of compression K which are of practical interest, i.e., K approx. = 1000, at which thermonuclear plasma parameters can be achieved

  3. NIMROD calculations of energetic particle driven toroidal Alfvén eigenmodes

    Science.gov (United States)

    Hou, Yawei; Zhu, Ping; Kim, Charlson C.; Hu, Zhaoqing; Zou, Zhihui; Wang, Zhengxiong; Nimrod Team

    2018-01-01

    Toroidal Alfvén eigenmodes (TAEs) are gap modes induced by the toroidicity of tokamak plasmas in the absence of continuum damping. They can be excited by energetic particles (EPs) when the EP drive exceeds other dampings, such as electron and ion Landau damping, and collisional and radiative damping. A TAE benchmark case, which was proposed by the International Tokamak Physics Activity group, is studied in this work. The numerical calculations of linear growth of TAEs driven by EPs in a circular-shaped, large aspect ratio tokamak have been performed using the Hybrid Kinetic-MHD (HK-MHD) model implemented in the NIMROD code. This HK-MHD model couples a δf particle-in-cell representation of EPs with the 3D MHD representation of the bulk plasma through moment closure for the momentum conservation equation. Both the excitation of TAEs and their transition to energetic particle modes (EPMs) have been observed. The influence of EP density, temperature, density gradient, and position of the maximum relative density gradient, on the frequency and the growth rate of TAEs are obtained, which are consistent with those from the eigen-analysis calculations, kinetic-MHD, and gyrokinetic simulations for an initial Maxwellian distribution of EPs. The relative pressure gradient of EP at the radial location of the TAE gap, which represents the drive strength of EPs, can strongly affect the growth rate of TAEs. It is demonstrated that the mode transition due to EP drive variation leads to not only the change of frequency but also the change of the mode structure. This mechanism can be helpful in understanding the nonlinear physics of TAE/EPM, such as frequency chirping.

  4. SELECTION MOMENTS AND GENERALIZED METHOD OF MOMENTS FOR HETEROSKEDASTIC MODELS

    Directory of Open Access Journals (Sweden)

    Constantin ANGHELACHE

    2016-06-01

    Full Text Available In this paper, the authors describe the selection methods for moments and the application of the generalized moments method for the heteroskedastic models. The utility of GMM estimators is found in the study of the financial market models. The selection criteria for moments are applied for the efficient estimation of GMM for univariate time series with martingale difference errors, similar to those studied so far by Kuersteiner.

  5. Dynamical conservation of invariants by toroidal trajectories of guiding centres

    International Nuclear Information System (INIS)

    Misguich, J.H.

    1992-03-01

    The classical problem of calculating toroidal trajectories is treated here by comparing the results of two different methods in a given magnetic configuration, a standard divergence-free magnetic field model. The present work consists of adapting the analytical criteria of MERCIER et al. for classical toroidal trajectories, and to examine numerically the dynamical conservation of the toroidal invariant. The first method is based on the evolution equations for the guiding centres. These equations are then solved numerically (code TRATORIA) and the trajectories are drawn for different initial conditions. We use a modified standard model for the magnetic field, which insures a manifestly divergence-free field. Moreover we take into account the contribution of the poloidal field to the total strength of the magnetic field. These corrections contribute to the analytical expression of the conserved toroidal momentum. The latter is verified to be conserved by the present numerical simulation with a precision generally of the order of 10 -14 . The second method is based on the analytical treatment of the invariants to yield a semi-analytical (semi graphical) determination of the intersection point of a given trajectory with the equatorial plane. Both methods allows one to recover well-known toroidal trajectories with passing and trapped particles (bananas). The present analysis brings a clear description of some other, less well-known types of trajectories, namely the stagnation orbits, the smallest D-shape banana, some small circulating de-flated bananas, some huge classical bananas (potatoes), and the largest puffed bananas which exhibit only local mirroring, along with several kind of escaping or open trajectories which are of importance for fast ion losses and target damages in the machines

  6. Spontaneous pneumothorax in weightlifters.

    Science.gov (United States)

    Marnejon, T; Sarac, S; Cropp, A J

    1995-06-01

    Spontaneous pneumothorax is infrequently caused by strenuous exertion. To our knowledge there has only been one case of spontaneous pneumothorax associated with weightlifting reported in the medical literature. We describe three consecutive cases of spontaneous pneumothorax associated with weightlifting. We postulate that spontaneous pneumothorax in these patients may be secondary to improper breathing techniques. It is important that physicians and weight trainers be aware of the association between weight lifting and spontaneous pneumothorax and assure that proper instruction is given to athletes who work with weights.

  7. Achieving a high-Q response in metamaterials by manipulating the toroidal excitations

    Science.gov (United States)

    Fan, Yuancheng; Zhang, Fuli; Shen, Nian-Hai; Fu, Quanhong; Wei, Zeyong; Li, Hongqiang; Soukoulis, Costas M.

    2018-03-01

    The excitation of toroidal multipoles in metamaterials is investigated for a high-Q response at a subwavelength scale. In this paper, we explore the optimization of toroidal excitations in a planar metamaterial comprised of asymmetric split ring resonators (ASRRs). It is found that the scattering power of a toroidal dipole can be remarkably strengthened by adjusting the characteristic parameter of ASRRs: an asymmetric factor. Interestingly, the improvement in toroidal excitation accompanies an increment of the Q factor of the toroidal metamaterial; it is shown that both the scattering power of the toroidal dipole and the Q factor increase more than one order by changing the asymmetric factor of ASRRs. The optimization in the excitation of a toroidal multipole provides an opportunity to further increase the Q factor of the metamaterial and boost light-matter interactions at the subwavelength scale for potential applications in low-power nonlinear processing and sensitive photonic applications.

  8. Magnetic Moment of $^{59}$Cu

    CERN Multimedia

    2002-01-01

    Experiment IS358 uses the intense and pure beams of copper isotopes provided by the ISOLDE RILIS (resonance ionization laser ion source). The isotopes are implanted and oriented in the low temperature nuclear orientation set-up NICOLE. Magnetic moments are measured by $\\beta$-NMR. Copper (Z=29), with a single proton above the proton-magic nickel isotopes provides an ideal testground for precise shell model calculations of magnetic moments and their experimental verification. In the course of our experiments we already determined the magnetic moments of $^{67}$Ni, $^{67}$Cu, $^{68g}$Cu, $^{69}$Cu and $^{71}$Cu which provide important information on the magicity of the N=40 subshell closure. In 2001 we plan to conclude our systematic investigations by measuring the magnetic moment of the neutron-deficient isotope $^{59}$Cu. This will pave the way for a subsequent study of the magnetic moment of $^{57}$Cu with a complementary method.

  9. Stabilization of ballooning modes with sheared toroidal rotation

    International Nuclear Information System (INIS)

    Miller, R.L.; Waelbroeck, F.L.; Hassam, A.B.; Waltz, R.E.

    1995-01-01

    Stabilization of magnetohydrodynamic ballooning modes by sheared toroidal rotation is demonstrated using a shifted circle equilibrium model. A generalized ballooning mode representation is used to eliminate the fast Alfven wave, and an initial value code solves the resulting equations. The s-α diagram (magnetic shear versus pressure gradient) of ballooning mode theory is extended to include rotational shear. In the ballooning representation, the modes shift periodically along the field line to the next point of unfavorable curvature. The shift frequency (dΩ/dq, where Ω is the angular toroidal velocity and q is the safety factor) is proportional to the rotation shear and inversely proportional to the magnetic shear. Stability improves with increasing shift frequency and direct stable access to the second stability regime occurs when this frequency is approximately one-quarter to one-half the Alfven frequency, ω A =V A /qR. copyright 1995 American Institute of Physics

  10. Shock absorbing properties of toroidal shells under compression, 3

    International Nuclear Information System (INIS)

    Sugita, Yuji

    1985-01-01

    The author has previously presented the static load-deflection relations of a toroidal shell subjected to axisymmetric compression between rigid plates and those of its outer half when subjected to lateral compression. In both these cases, the analytical method was based on the incremental Rayleigh-Ritz method. In this paper, the effects of compression angle and strain rate on the load-deflection relations of the toroidal shell are investigated for its use as a shock absorber for the radioactive material shipping cask which must keep its structural integrity even after accidental falls at any angle. Static compression tests have been carried out at four angles of compression, 10 0 , 20 0 , 50 0 , 90 0 and the applications of the preceding analytical method have been discussed. Dynamic compression tests have also been performed using the free-falling drop hammer. The results are compared with those in the static compression tests. (author)

  11. Toroidal coupling in the kinetic response to edge magnetic perturbations

    Science.gov (United States)

    Spizzo, G.; Agostini, M.; Scarin, P.; White, R. B.; Schmitz, O.; Spolaore, M.; Terranova, D.; Veranda, M.; Vianello, N.

    2017-12-01

    The magnetic topology of the stochastic edge of a helical reversed-field pinch, with helicity m/n , shows to be deeply influenced by higher harmonics (m +/- 1)/ n , with the same n, due to toroidal coupling. As a consequence, by measuring kinetic quantities in a particular θ, φ location, one can incur in substantial errors or mis-interpretations of the kinetic plasma response: only a full 3D coverage of θ, φ angles can reveal the real topology of the plasma. This can be a caveat for MP application in tokamaks, because it shows that toroidal and poloidal sidebands, though smaller than the base mode by a factor  ∼ \

  12. Compact toroid injection experiment in JFT-2M

    International Nuclear Information System (INIS)

    Ogawa, T.; Fukumoto, N.; Nagata, M.

    2001-01-01

    Compact toroid (CT)injection experiments with H-mode plasmas were carried out for the first time in JFT-2M. The soft x-ray emission profile shows central penetration of CT in H-mode plasma heated by 1.2 MW NBI as well as in OH plasmas, with toroidal magnetic field of 0.8 T. The line-averaged electron density rapidly increased by Δn-bar e ∝0.2x10 19 m -3 at a rate of 4x10 21 m -3 /s in H-mode and the fuelling efficiency was roughly 20%.The asymmetrical radial profile in the soft x-ray emission was produced for ∝ 50 μs by the central penetration of CT. (author)

  13. Magnetohydrodynamic equilibrium of axisymmetric systems with toroidal rotation

    International Nuclear Information System (INIS)

    Mansur, N.L.P.

    1986-01-01

    A model for studying magnetohydrodynamic equilibrium of axisymetrically confined plasma with toroidal rotation, extended to the Grad. Shafranov equation is presented. The expression used for the scalar pressure is modifiec, and the influence of toroidal magnetic field is included, The equation for general motion of axisymetrically confined plasma, particularizing for rotation movements is described. Two cases are compared: one supposes the entropy as a function of poloidal magnetic flux and other supposes the temperature as a function of flux. The equations for these two cases obtaining a simplified expression by others approximations are established. The proposed model is compared with Shibata model, which uses density as function of flux, and with the ideal spheromak model. A set of cases taking in account experimental data is studied. (M.C.K.) [pt

  14. A toroidal inductor integrated in a standard CMOS process

    DEFF Research Database (Denmark)

    Vandi, Luca; Andreani, Pietro; Temporiti, Enrico

    2007-01-01

    This paper presents a toroidal inductor integrated in a standard 0.13 um CMOS process. Finite-elements preliminary simulations are provided to prove the validity of the concept. In order to extract fundamental parameters by means of direct calculations, two different and well-known approaches are......H and 1.1 nH up to 20 GHz (physical limit for the measurement equipment) and a quality factor approaching 10 at 15 GHz. No self-resonance is observed within the measurement range.......This paper presents a toroidal inductor integrated in a standard 0.13 um CMOS process. Finite-elements preliminary simulations are provided to prove the validity of the concept. In order to extract fundamental parameters by means of direct calculations, two different and well-known approaches...

  15. A comparison between linear and toroidal Extrap systems

    International Nuclear Information System (INIS)

    Lehnert, B.

    1988-09-01

    The Extrap scheme consists of a Z-pinch immersed in an octupole field generated by currents in a set of external conductors. A comparison between linear and toroidal Extrap geometry is made in this paper. As compared to toroidal systems, linear geometry has the advantages of relative simplicity and of a current drive by means of electrodes. Linear devices are convenient for basic studies of Extrap, at moderately high pinch currents and plasma temperatures. Within the parameter ranges of experiments at high pinch currents and plasma temperatures, linear systems have on the other hand some substantial disadvantages, on account of the plasma interaction with the end regions. This results in a limitation of the energy confinement time, and leads in the case of an ohmically heated plasma to excessively high plasma densities and small pinch radii which also complicate the introduction of the external conductors. (author)

  16. Kinetic global analysis of Alfven eigenmodes in toroidal plasmas

    International Nuclear Information System (INIS)

    Fukuyama, A.

    2002-01-01

    Systematic study on low to medium n (toroidal mode number) Alfven eigenmodes (AE) in tokamaks and helical systems is presented. Linear stability of AE in the presence of energetic ions was studied using the kinetic full-wave code TASK/WM.We have reproduced the destabilizing effect of toroidal co-rotation on TAE for JT-60U parameters. We have found the existence of reversed-shear-induced Alfven eigenmode (RSAE) which localizes near the q minimum in a reversed magnetic shear configuration. Two kinds of mode structures are identified for energetic particle mode (EPM) below the TAE frequency gap. The coupling to lower-frequency modes such as drift waves and MHD modes as well as the effect of trapped particles are also taken into account. For a helical plasma, the existence of GAE in the central region and TAE in the off-axis region was confirmed. (author)

  17. Control and monitoring of the Tore Supra toroidal superconducting coils

    International Nuclear Information System (INIS)

    Prou, M.

    1989-07-01

    Light nuclei controlled fusion reactions are seen as a possible way to produce nuclear energy. For this reason, the interest in hot plasma researches in tokamaks has increased. The Tore Supra main characteristic is related to the superconducting magnet coils. They allow a suitable energy balance, however, they require an accurate and preventive fault detection. The Tore Supra machine and the different methods to detect a transition (from superconducting to normal mode) in the toroidal coils are described. The voltage of the coils, the pressure of the helium superfluid at 1.8 K and the electric current in the circuit parallel resistances, are measured. A computer aided control system allows the toroidal field monitoring (current in the coils, fault detection). The superconducting magnet configuration chosen for Tore Supra seems to be suitable for future large Tokamak devices [fr

  18. ATLAS barrel toroid integration and test area in building 180

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    The ATLAS barrel toroid system consists of eight coils, each of axial length 25.3 m, assembled radially and symmetrically around the beam axis. The coils are of a flat racetrack type with two 'double-pancake' windings made of 20.5 kA aluminium-stabilized niobium-titanium superconductor. The barrel toroid is being assembled in building 180 on the Meyrin site. In the first phase of assembly, the coils are packed into their aluminium-alloy casing. These photos show the double-pancake coils from ANSALDO and the coil casings from ALSTOM. In the foreground is the tooling from COSMI used to turn over the coil casings during this first phase. In the right background is the yellow lifting gantry manufactured at JINR-Dubna, Russia which will transport the coil casings to a heating table for prestressing. Two test benches with magnetic mirror are also visible.

  19. Generation of DC toroidal current by a travelling wave

    International Nuclear Information System (INIS)

    Matsuura, K.; Fukuda, M.; Hirano, K.; Mohri, A.; Fukao, M.; Midzuno, Y.

    1974-01-01

    An rf field travelling along the torus is observed to induce a dc toroidal current in a magnetized plasma. The travelling field is applied to the plasma by employing a delay-line wound around the toroidal glass discharge tube. The phase velocity of the field is approximately equal to the electron thermal velocity. The direction of the current is opposite to that of the wave, indicating that the electrons are trapped in the magnetic mirrors composed of the travelling wave. The density of the trapped electrons reaches 10 percent of the background plasma density at an optimum condition. On the basis of the electron trapping model, the required rf power for current sustaining in a Tokamak fusion reactor is estimated and found to be reasonably small in comparison with the output power of the reactor

  20. Broadening of the lower hybrid kparallel spectrum by toroidal effects

    International Nuclear Information System (INIS)

    Barbato, E.; Romanelli, F.

    1990-01-01

    Toroidal geometry affects the evolution of k parallel (the component of the wave vector parallel to the magnetic field) along the lower hybrid, (LH) wave trajectories. In this paper such variations are investigated both analytically and numerically. The main parameters governing this phenomenon are found and how k parallel upshift can occur within this scheme is elucidated. As a figure of merit a k parallel - upshift factor is defined and discussed in a dimensionless parameter space in which all the LH experiments can be represented. Finally, a discussion of whether and when toroidal effects can fill the gap between the high phase velocity of the injected LH waves and the electron thermal velocity is presented by analyzing different experimental situations

  1. Internal transport barrier triggered by non-linear lower hybrid wave deposition under condition of beam-driven toroidal rotation

    International Nuclear Information System (INIS)

    Gao, Q. D.; Budny, R. V.

    2015-01-01

    By using gyro-Landau fluid transport model (GLF23), time-dependent integrated modeling is carried out using TRANSP to explore the dynamic process of internal transport barrier (ITB) formation in the neutral beam heating discharges. When the current profile is controlled by LHCD (lower hybrid current drive), with appropriate neutral beam injection, the nonlinear interplay between the transport determined gradients in the plasma temperature (T i,e ) and toroidal velocity (V ϕ ) and the E×B flow shear (including q-profile) produces transport bifurcations, generating spontaneously a stepwise growing ITB. In the discharge, the constraints imposed by the wave propagation condition causes interplay of the LH driven current distribution with the plasma configuration modification, which constitutes non-linearity in the LH wave deposition. The non-linear effects cause bifurcation in LHCD, generating two distinct quasi-stationary reversed magnetic shear configurations. The change of current profile during the transition period between the two quasi-stationary states results in increase of the E×B shearing flow arising from toroidal rotation. The turbulence transport suppression by sheared E×B flow during the ITB development is analysed, and the temporal evolution of some parameters characterized the plasma confinement is examined. Ample evidence shows that onset of the ITB development is correlated with the enhancement of E×B shearing rate caused by the bifurcation in LHCD. It is suggested that the ITB triggering is associated with the non-linear effects of the LH power deposition

  2. Variation of magnetic properties of toroidal cores with magnetizing frequency

    International Nuclear Information System (INIS)

    Derebasi, N.; Rygal, R.; Moses, A.J.; Fox, D.

    2000-01-01

    AC magnetic properties of toroidal cores made from six different soft magnetic materials were measured. A solid steel core exhibited the highest remanance, coercivity and core loss as expected whereas a nanocrystalline core had the lowest remanance of the cores tested. Increase in dynamic core loss with frequency in steel particle and iron powder cores was low compared with the other cores but was low in permeability

  3. Force-free field inside a toroidal magnetic cloud

    Czech Academy of Sciences Publication Activity Database

    Romashets, E. P.; Vandas, Marek

    2003-01-01

    Roč. 30, č. 20 (2003), s. 2065, /SSC 8-1 - SSC 8-4/ ISSN 0094-8276 R&D Projects: GA AV ČR IBS1003006; GA ČR GA205/03/0953 Institutional research plan: CEZ:AV0Z1003909 Keywords : magnetic clouds * toroid al flux rope * analytical solution Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 2.422, year: 2003

  4. A numerical solution for a toroidal plasma in equilibrium

    International Nuclear Information System (INIS)

    Hintz, E.; Sudano, J.P.

    1982-01-01

    The iterative techniques alternating direction implicit (ADI), sucessive ove-relaxation (SOR) and Gauss-Seidel are applied to a nonlinear elliptical second order differential equation (Grand-Shafranov). This equation was solve with the free boundary conditions plasma-vacuum interface over a rectangular section in cylindrical coordinates R and Z. The current density profile, plasma pressure profile, magnetic and isobaric surfaces are numerically determined for a toroidal plasma in equilibrium. (L.C.) [pt

  5. Theory of the rippling instability in toroidal devices

    International Nuclear Information System (INIS)

    Rogister, A.

    1985-04-01

    The theory of the rippling instability is developed for axisymmetric toroidal plasmas including ion viscosity and parallel electron heat conduction, but assuming that the growth rate is small compared to the wave angular frequency. Parallel electron heat conduction is stabilizing but ion viscosity broadens the instability domain. Under certain conditions, an important top-bottom asymmetry of the density fluctuation spectrum may arise. (orig./GG)

  6. Goya - an MHD equilibrium code for toroidal plasmas

    International Nuclear Information System (INIS)

    Scheffel, J.

    1984-09-01

    A description of the GOYA free-boundary equilibrium code is given. The non-linear Grad-Shafranov equation of ideal MHD is solved in a toroidal geometry for plasmas with purely poloidal magnetic fields. The code is based on a field line-tracing procedure, making storage of a large amount of information on a grid unnecessary. Usage of the code is demonstrated by computations of equi/libria for the EXTRAP-T1 device. (Author)

  7. Operating tokamaks with steady-state toroidal current

    International Nuclear Information System (INIS)

    Fisch, N.J.

    1981-04-01

    Continuous operation of a tokamak requires, among other things, a means of continuously providing the toroidal current. Various methods have been proposed to provide this current including methods which utilize radio-frequency waves in any of several frequency regimes. Here we elaborate on the prospects of incorporating these current-drive techniques in tokamak reactors, concentrating on the theoretical minimization of the power requirements

  8. Modular invariant partition functions for toroidally compactified bosonic string

    International Nuclear Information System (INIS)

    Ardalan, F.; Arfaei, H.

    1988-06-01

    We systematically find all the modular invariant partition functions for the toroidally compactified closed bosonic string defined on a subset of a simply laced simple Lie algebra lattice, or equivalently for the closed bosonic string moving on a group manifold with the WZW coefficient k=1. We examine the relation between modular invariance of partition function and the possibility of describing it by an even Lorentzian self dual lattice in our context. (author). 23 refs

  9. The control system of the RFX toroidal power supply

    International Nuclear Information System (INIS)

    Toigo, V.; Piovan, R.; Zanotto, L.; Perna, M.; Coffetti, A.; Freghieri, M.; Povolero, M.

    2005-01-01

    This paper describes the control system of the toroidal power supply of the RFX experiment and outlines its specific hardware and software structure, which allowed to cope with the numerous requirements of the application with a compact hardware arrangement. The active fault protection strategies, implemented in the control system, are also discussed; finally, a special part of the control, which greatly simplified the long and complex commissioning of the power section of the system, is described

  10. Miniature anastigmatic spectrometer design with a concave toroidal mirror.

    Science.gov (United States)

    Dong, Jianing; Chen, He; Zhang, Yinchao; Chen, Siying; Guo, Pan

    2016-03-01

    An advanced optical design for a low-cost and astigmatism-corrected spectrometer with a high resolution is presented. The theory and method of astigmatism correction are determined with the use of a concave toroidal mirror. The performances of a modified spectrometer and a traditional spectrometer are compared, and the analysis is verified. Experimentally, the limiting resolution of our spectrometer is 0.1 nm full width at half-maximum, as measured for 579.1 nm.

  11. CPRF/ZTH toroidal conducting shell design and fabrication considerations

    International Nuclear Information System (INIS)

    Ballard, E.O.; Gomez, T.; Smith, R.L.; Weldon, D.M.

    1987-01-01

    The authors discuss design in progress of a new generation Reversed Field Pinch (RFP) machine to be fabricated and assembled at Los Alamos National Laboratory during FY 86-92. The Confinement Physics Research Facility (CPRF) houses the front-end ZTH torus. The ZTH consists oof an Inconel 625 vacuum liner supported by an external electrically conducting shell. The shell also supports 48 toroidal field coils that are mounted to the shells external surface

  12. Curvature-induced electrostatic drift modes in a toroidal plasma

    International Nuclear Information System (INIS)

    Venema, M.

    1985-01-01

    This thesis deals with a number of problems in the theory of linear stability of a hot, fully ionized plasma immersed in a strong magnetic field. The most widely used system to magnetically confine a plasma is the tokamak. This is a toroidal, current carrying device with a strong, externally imposed, magnetic field. The author discusses the linear theory of unstable, low-frequency waves in the gradient region, restricted to electrostatic waves. In that case the resulting radial fluxes of particles and energy are due to electric cross-field drifts. In the presence of magnetic fluctuations and small-scale reconnection phenomena, radial transport could also be predominantly along field lines. At present, it is not clear which of the two mechanisms is the dominant feature of the observed anomalous transport. First, the author introduces the theory of drift waves in toroidal geometry. Next, the electrostratic drift modes in toroidal geometry (weakly collisional regime), the equations for low-frequency waves in the strongly collisional regime and the electrostatic drift modes (strongly collisional regime) are discussed. (Auth.)

  13. Plasma confinement of Nagoya high beta toroidal pinch experiments

    International Nuclear Information System (INIS)

    Hirano, K.; Kitagawa, S.; Wakatani, M.; Kita, Y.; Yamada, S.; Yamaguchi, S.; Sato, K.; Aizawa, T.; Osanai, Y.; Noda, N.

    1976-01-01

    Two different types of high β toroidal pinch experiments, STP and CCT, have been done to study the confinement of the plasma produced by theta-pinch. The STP is an axisymmetric toroidal pinch of high β tokamak type, while the CCT is multiply connected periodic toroidal traps. Internal current carrying copper rings are essential to the CCT. Since both apparatuses use the same fast capacitor bank system, they produce not so different plasma temperatures and densities. The observed laser scattering temperature and density is about 50 eV and 4 x 10 15 /cm 3 , respectively, when the filling pressure is 5 m torr. In the experiment of STP, strong correlations are found between the βsub(p) value and the amplitude of m = 2 mode. It has a minimum around the value of βsub(p) of 0.8. The disruptive instability is observed to expand the pinched plasma column without lowering the plasma temperature. Just before the distruption begins, the q value around the magnetic axis becomes far less than 1 and an increase of the amplitude of m = 2 mode is seen. The CCT also shows rapid plasma expansion just before the magnetic field reaches its maximum. Then the trap is filled up with the plasma by this irreversible expansion and the stable plasma confinement is achieved. The energy confinement time of the CCT is found to be about 35 μsec. (orig.) [de

  14. Toroidal Continuously Variable Transmission Systems: Terminology and Present Studies

    Directory of Open Access Journals (Sweden)

    Ahmet YILDIZ

    2014-04-01

    Full Text Available The use of continuously variable transmission systems in many different areas such as aerospace, robotics, machinery and automotive industries as an alternative to conventional speed changers with constant ratio becomes widely.Especially in the automotive industry, these systems have been used increasingly, since they enable that internal combustion engines in vehicles run at optimal speeds, and consequently provide considerable fuel savings and therefore lower emission values and also they provide powerful acceleration and quiet working. CVT systems have several constructive variants such as belted, chained, balled, toroidal etc. In this paper, toroidal CVT systems based on elastohydrodynamic principles are concerned with, and fundamental works of last two decades in this field are reviewed. However, the relevant terminology and dynamics along with the control of these systems are briefly treated for better understanding of the literature mentioned. Attention is drawn to the lack of some significant issues in present research works, and potential future works are pointed out. This paper, to the authors’ knowledge, will be the first review on toroidal CVT systems in Turkish literature

  15. Toroidal plasma reactor with low external magnetic field

    International Nuclear Information System (INIS)

    Beklemishev, A.D.; Khayrutdinov, R.R.; Petviashvili, V.I.; Tajima, T.; Gordin, V.A.; Tajima, T.

    1991-01-01

    A toroidal pinch configuration with safety factor q < 0.5 decreasing from the center to periphery without field reversal is proposed. This is capable of containing high pressure plasma with only small toroidal external magnetic field. Sufficient conditions for magnetohydrodynamic stability are fulfilled in this configuration. The stability is studied by constructing the Lyapunov functional and investigating its extrema both analytically and numerically. Comparison of the Lyapunov stability conditions with the conventional linear theory is carried out. Stable configurations are found with average β near 15%, with magnetic field associated mainly with plasma current. The β value calculated with the external magnetic field can be over 100%. Fast charged particles produced by fusion reactions are asymmetrically confined by the poloidal magnetic field (and due to the lack of strong toroidal field). They thus generate a current in the noncentral part of plasma to reinforce the poloidal field. This current drive can sustain the monotonic decrease of q with radius. 20 refs., 9 figs

  16. Spontaneous sensorimotor coupling with multipart music.

    Science.gov (United States)

    Hurley, Brian K; Martens, Peter A; Janata, Petr

    2014-08-01

    Music often evokes spontaneous movements in listeners that are synchronized with the music, a phenomenon that has been characterized as being in "the groove." However, the musical factors that contribute to listeners' initiation of stimulus-coupled action remain unclear. Evidence suggests that newly appearing objects in auditory scenes orient listeners' attention, and that in multipart music, newly appearing instrument or voice parts can engage listeners' attention and elicit arousal. We posit that attentional engagement with music can influence listeners' spontaneous stimulus-coupled movement. Here, 2 experiments-involving participants with and without musical training-tested the effect of staggering instrument entrances across time and varying the number of concurrent instrument parts within novel multipart music on listeners' engagement with the music, as assessed by spontaneous sensorimotor behavior and self-reports. Experiment 1 assessed listeners' moment-to-moment ratings of perceived groove, and Experiment 2 examined their spontaneous tapping and head movements. We found that, for both musically trained and untrained participants, music with more instruments led to higher ratings of perceived groove, and that music with staggered instrument entrances elicited both increased sensorimotor coupling and increased reports of perceived groove. Although untrained participants were more likely to rate music as higher in groove, trained participants showed greater propensity for tapping along, and they did so more accurately. The quality of synchronization of head movements with the music, however, did not differ as a function of training. Our results shed new light on the relationship between complex musical scenes, attention, and spontaneous sensorimotor behavior.

  17. Transport processes and entropy production in toroidally rotating plasmas with electrostatic turbulence

    International Nuclear Information System (INIS)

    Sugama, H.; Horton, W.

    1996-08-01

    Transport processes and resultant entropy production in magnetically confined plasmas are studied in detail for toroidally rotating systems with electrostatic turbulence. A new gyrokinetic equation is derived for rotating plasmas with large flow velocities on the order of the ion thermal speed. Neoclassical and anomalous transport of particles, energy, and toroidal momentum are systematically formulated from the ensemble-averaged kinetic equation with the gyrokinetic equation. As a conjugate pair of the thermodynamic force and the transport flux, the shear of the toroidal flow, which is caused by the radial electric field shear, and the toroidal viscosity enter both the neoclassical and anomalous entropy production. The interaction between the fluctuations and the sheared toroidal flow is self-consistently described by the gyrokinetic equation containing the flow shear as the thermodynamic force and by the toroidal momentum balance equation including the anomalous viscosity. Effects of the toroidal flow shear on the toroidal ion temperature gradient driven modes are investigated. Linear and quasilinear analyses of the modes show that the toroidal flow shear decreases the growth rates and reduces the anomalous toroidal viscosity. (author)

  18. Moment Magnitude discussion in Austria

    Science.gov (United States)

    Weginger, Stefan; Jia, Yan; Hausmann, Helmut; Lenhardt, Wolfgang

    2017-04-01

    We implemented and tested the Moment Magnitude estimation „dbmw" from the University of Trieste in our Antelope near real-time System. It is used to get a fast Moment Magnitude solutions and Ground Motion Parameter (PGA, PGV, PSA 0.3, PSA 1.0 and PSA 3.0) to calculate Shake and Interactive maps. A Moment Magnitude Catalogue was generated and compared with the Austrian Earthquake Catalogue and all available Magnitude solution of the neighbouring agencies. Relations of Mw to Ml and Ground Motion to Intensity are presented.

  19. Dimensional reduction and moment maps

    Science.gov (United States)

    Nagatomo, Yasuyuki

    2002-03-01

    We give a unified viewpoint of moment maps in the case of symplectic, hyper-Kähler, quaternion-Kähler and holomorphic contact manifolds. The Higgs field can be regarded as a moment map under some additional conditions in each case. Using dimensional reductions and moment maps, we reduce the standard 1 instanton on HP 1≅S 4 to an SO(3) instanton on CP 1× CP 1 and the standard 1 instanton on HP n to the standard 1 instanton on Gr 2( Cn+1) .

  20. Magnetic moment of 33Cl

    International Nuclear Information System (INIS)

    Matsuta, K.; Arimura, K.; Nagatomo, T.; Akutsu, K.; Iwakoshi, T.; Kudo, S.; Ogura, M.; Takechi, M.; Tanaka, K.; Sumikama, T.; Minamisono, K.; Miyake, T.; Minamisono, T.; Fukuda, M.; Mihara, M.; Kitagawa, A.; Sasaki, M.; Kanazawa, M.; Torikoshi, M.; Suda, M.; Hirai, M.; Momota, S.; Nojiri, Y.; Sakamoto, A.; Saihara, M.; Ohtsubo, T.; Alonso, J.R.; Krebs, G.F.; Symons, T.J.M.

    2004-01-01

    The magnetic moment of 33 Cl (Iπ=3/2+, T1/2=2.51s) has been re-measured precisely by β-NMR method. The obtained magnetic moment |μ|=0.7549(3)μN is consistent with the old value 0.7523(16)μN, but is 5 times more accurate. The value is well reproduced by the shell model calculation, μSM=0.70μN. Combined with the magnetic moment of the mirror partner 33 S, the nuclear matrix elements , , , and were derived

  1. Compact toroidal energy storage device with relativistically densified electrons through the use of travelling magnetic waves

    International Nuclear Information System (INIS)

    Peter, W.; Faehl, R.J.

    1983-01-01

    A new concept for a small compact multimegajoule energy storage device utilizing relativistically densified electron beam circulating in a torus is presented. The electron cloud is produced through inductive charge injection by a travelling magnetic wave circulating the torus. Parameters are given for two representative toroidal energy storage devices, consisting of 1 m and 32 m in radius respectively, which could store more than 4 x 10 17 electrons and 30' MJ in energy. The concept utilizes the idea that large electric and magnetic fields can be produced by a partially space-charge neutralized intense relativistic electron beam which could become many orders of magnitude greater than the externally applied field confining the beam. In the present approach, the electron cloud densification can be achieved gradually by permitting multiple traversals of the magnetic wave around the torus. The magnetic mirror force acts on the orbital magnetic electron dipole moment and completely penetrates the entire electron cloud. As the electrons gain relativistic energies, the beam can be continuously densified at the front of the travelling wave, where the magnetic field is rising with time. The use of travelling magnetic wave to accelerate an electron cloud and the use of large electric field at the thusly accelerated cloud form the basis for a high beam intensity and hence high energy storage. Technical considerations and several potential applications, which include the driving of a powerful gyrotron, are discussed

  2. Electrically Controllable Spontaneous Magnetism in Nanoscale Mixed Phase Multiferroics

    Energy Technology Data Exchange (ETDEWEB)

    He, Q.; Chu, Y. H.; Heron, J. T.; Yang, S. Y.; Wang, C. H.; Kuo, C. Y.; Lin, H. J.; Yu, P.; Liang, C. W.; Zeches, R. J.; Chen, C. T.; Arenholz, E.; Scholl, A.; Ramesh, R.

    2010-08-02

    The emergence of enhanced spontaneous magnetic moments in self-assembled, epitaxial nanostructures of tetragonal (T-phase) and rhombohedral phases (R-phase) of the multiferroic BiFeO{sub 3} system is demonstrated. X-ray magnetic circular dichroism based photoemission electron microscopy (PEEM) was applied to investigate the local nature of this magnetism. We find that the spontaneous magnetization of the R-phase is significantly enhanced above the canted antiferromagnetic moment in the bulk phase, as a consequence of a piezomagnetic coupling to the adjacent T-phase and the epitaxial constraint. Reversible electric field control and manipulation of this magnetic moment at room temperature is shown using a combination of piezoresponse force microscopy and PEEM studies.

  3. Fast computation of Krawtchouk moments

    Czech Academy of Sciences Publication Activity Database

    Honarvar Shakibaei Asli, B.; Flusser, Jan

    2014-01-01

    Roč. 288, č. 1 (2014), s. 73-86 ISSN 0020-0255 R&D Projects: GA ČR GAP103/11/1552 Institutional support: RVO:67985556 Keywords : Krawtchouk polynomial * Krawtchouk moment * Geometric moment * Impulse response * Fast computation * Digital filter Subject RIV: JD - Computer Applications, Robotics Impact factor: 4.038, year: 2014 http://library.utia.cas.cz/separaty/2014/ZOI/flusser-0432452.pdf

  4. Moment Distributions of Phase Type

    DEFF Research Database (Denmark)

    Bladt, Mogens; Nielsen, Bo Friis

    2011-01-01

    Moment distributions of phase-type and matrix-exponential distributions are shown to remain within their respective classes. We provide a probabilistic phase-type representation for the former case and an alternative representation, with an analytically appealing form, for the latter. First order...... moment distributions are of special interest in areas like demography and economics, and we calculate explicit formulas for the Lorenz curve and Gini index used in these disciplines....

  5. Spontaneous uterine rupture

    African Journals Online (AJOL)

    ABSTRACT. Rupture of a gravid uterus is a surgical emergency. Predisposing factors include a scarred uterus. Spontaneous rupture of an unscarred uterus during pregnancy is a rare occurrence. We hereby present the case of a spontaneous complete uterine rupture at a gestational age of 34 weeks in a 35 year old patient ...

  6. Spontaneous intracranial hypotension.

    LENUS (Irish Health Repository)

    Fullam, L

    2012-01-31

    INTRODUCTION: Spontaneous\\/primary intracranial hypotension is characterised by orthostatic headache and is associated with characteristic magnetic resonance imaging findings. CASE REPORT: We present a case report of a patient with typical symptoms and classical radiological images. DISCUSSION: Spontaneous intracranial hypotension is an under-recognised cause of headache and can be diagnosed by history of typical orthostatic headache and findings on MRI brain.

  7. Microscopic Description of Electric and Magnetic Toroidal Multipoles in Hybrid Orbitals

    Science.gov (United States)

    Hayami, Satoru; Kusunose, Hiroaki

    2018-03-01

    We derive the quantum-mechanical operator expressions of multipoles under the space-time inversion group. We elucidate that electric and magnetic toroidal multipoles, in addition to ordinary non-toroidal ones, are fundamental pieces to express arbitrary electronic degrees of freedom. We show that electric (magnetic) toroidal multipoles higher than the dipole (monopole) can become active in a hybridized-orbital system. We also demonstrate emergent cross-correlated couplings between the electric, magnetic, and elastic degrees of freedom, such as magneto-electric and magneto(electro)-elastic coupling, under toroidal multipole orders.

  8. The comparative analysis of the different mechanisms of toroidal rotation in tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Sabot, R. [Association Euratom-CEA, Centre d`Etudes Nucleaires de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Parail, V. [Kurchatov Institute, Moscow (Russian Federation)

    1994-07-01

    The toroidal plasma rotation appears as one the possible mechanism for suppression of plasma turbulence. Several mechanisms are believed to contribute to the toroidal plasma rotation. The results of numerical simulation of the toroidal rotation on JET are presented, where are taken into consideration the following effects: the neoclassical viscosity due to banana and ripple trapped particles, the anomalous viscosity due to plasma turbulence, the momentum input by NBI (neutron beam injection) and ion momentum loss near the separatrix due to prompt ion losses. The NBI appeared to be the principal source of toroidal plasma rotation. 6 refs., 2 figs.

  9. Modeling the shape of a noncircular toroidal field coil

    International Nuclear Information System (INIS)

    Shah, V.N.; Marshall, N.H.

    1983-01-01

    Operating and transient forces acting on toroidal field coils may cause conductors and insulation to slide or break and may lead to quenching of the coil. Therefore, it is essential that each individual turn of the coil be modeled for detailed analysis of the coil structure. For this, a special purpose computer program is needed. As a first step in developing such a computer program, the authors present a finite element analysis of a turn of noncircular coil subjected to electromagnetic loading. A turn of superconducting coil is represented by a thin ring modeled by curved finite elements. Of the several curved beam elements reported in the literature, the strain element with two nodes, six degrees-of-freedom, and constant radius of curvature converges fastest for thin-deep arches whose geometrical characteristics are similar to those of a turn of toroidal field coil. They present an algorithm to model a noncircular ring using the number of strain elements satisfying the continuity of slopes at their nodes. This paper verifies the finite element model of a coil shape subjected to a toroidal magnetic field by solving three problems: circular and elliptic coils with the same inner and outer radii, a D-shaped coil, and a compound coil consisting of C- and D-shaped segments. The first problem shows that the resultant vertical force in the upper half of the coil is independent of coil shape. The remaining two problems calculate stresses that represent the constant tension in the D-shaped coil and in each segment of the compound coil. The results of the three problems compare well with the analytical results

  10. Spontaneous and artificial generation of sheared flow in oblate FRCs in TS-3 and 4 FRC experiments

    International Nuclear Information System (INIS)

    Matsuyama, T.; Kawamori, E.; Ono, Y.; Tsuruda, M.; Sato, K.; Yamanoue, T.; Arimoto, K.; Itagaki, T.; Katsurai, M.

    2003-01-01

    Spontaneous formation of toroidal flow was measured for the first time in oblate FRCs produced in TS-3 and 4 experiments. The toroidal ion flow (V i ∼10km/sec) was found to peak around the magnetic axis, indicating formation of high flow shear inside the separatrix. The toroidal flow was observed to deform the magnetic field lines of the FRC, producing bipolar toroidal field profile. In high-s FRC (averaged number of ion gyro-radius 's'=4.5) with slow flow, its n=1 mode kept growing, causing collapse of the whole configuration. However, in low-s FRC (s=3) with fast flow, the rotating n=2 mode (saturated) became dominant after n=1 mode saturation. The spontaneous formation of flow shear possibly transformed the n=1 mode into the n=2 mode, suggesting a new sheared flow stabilization of n=1 mode. The flow shear was also generated artificially using the 'sling shot' effect of the counter helicity reconnection. The n=1 and 2 mode amplitudes were reduced down to 1/5-1/10 due to the generated flow shear. A new method for continuous sheared-flow generation was proposed for stabilization and heating of FRC by use of intermittent merging of spheromaks with opposing B t . (author)

  11. Image Recognition Using Modified Zernike Moments

    Directory of Open Access Journals (Sweden)

    Min HUANG

    2014-03-01

    Full Text Available Zernike moments are complex moments with the orthogonal Zernike polynomials as kernel function, compared with other moments; Zernike moments have greater advantages in image rotation and low noise sensitivity. Because of the Zernike moments have image rotation invariance, and can construct arbitrary high order moments, it can be used for target recognition. In this paper, the Zernike moment algorithm is improved, which makes it having scale invariance in the processing of digital image. At last, an application of the improved Zernike moments in image recognition is given.

  12. Direct measurement of the damping of toroidicity induced Alfven eigenmodes

    International Nuclear Information System (INIS)

    Fasoli, A.; Lister, J.B.; Moret, J.M.; Lavanchy, P.; Marmillod, P.; Sharapov, S.; Borba, D.; Bosia, G.; Campbell, D.J.; Dobbing, J.A.; Gormezano, C.; Jacquinot, J.; Santagiustina, A.

    1995-01-01

    This paper presents the first direct experimental measurements of the damping of toroidicity induced Alfven eigenmodes (TAE), carried out in the JET tokamak. These measurements were obtained during the first experiments to drive these modes with antennas external to a tokamak plasma. Different regimes corresponding to different dominant TAE absorption mechanisms with a wide range of damping rates, 10 -3 ≤γ/ω≤10 -1 , have been identified in ohmically heated plasma discharges using this new active diagnostic for Alfven eigenmodes. (author) 5 figs., tabs., 25 refs

  13. Transport mechanisms acting in toroidal devices: a theoretician's view

    International Nuclear Information System (INIS)

    Carreras, B.A.

    1992-01-01

    Understanding the basic mechanisms of transport in toroidal confinement devices remains one of the more challenging scientific issues in magnetic confinement. At the same time, it is a critical issue for the magnetic fusion program. Recent progress in understanding fluctuations and transport has been fostered by the development and use of new diagnostics, bringing new perspectives on these studies. This has stimulated new theoretical developments. A view of the most recent issues and progress in this area is given. The role of long wavelengths in core transport and the relation between shear flows and turbulence at the plasma edge are the primary topics considered. (Author)

  14. Simulated and experimental compression of a compact toroid

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J N; Hwang, D Q; Horton, R D; Evans, R W; Owen, J M

    2009-05-06

    We present simulation results and experimental data for the compression of a compact toroid by a conducting nozzle without a center electrode. In both simulation and experiment, the flow of the plasma is greatly obstructed by even modest magnetic fields. A simple mechanism for this obstruction is suggested by our simulations. In particular, the configuration of the plasmoid's magnetic field plays a significant role in the success of the experiment. We analyze two types of plasma configurations under compression and demonstrate that the results from the simulations matches those from the experiments, and that the mechanism predicts the different behaviors observed in the two cases.

  15. Experimental progress on zonal flow physics in toroidal plasmas

    International Nuclear Information System (INIS)

    Fujisawa, A.; Ido, T.; Shimizu, A.; Okamura, S.; Matsuoka, K.; Hamada, Y.; Nakano, H.; Ohshima, S.; Hoshino, Katsumichi; Shinohara, Koji; Miura, Yukitoshi

    2006-10-01

    Present status of experiments on zonal flows is overviewed. Innovative use of traditional and modern diagnostics has revealed unambiguously the existence of zonal flows, their spatio-temporal characteristics, their relationship with turbulence, and their effects on confinement. Particularly, a number of observations have been accumulated on the oscillatory branch of zonal flows, dubbed geodesic acoustic modes, suggesting necessity of theories to give their proper description. In addition to these basic properties of zonal flows, several new methods have elucidated the zonal flow generation processes from turbulence. Further investigation of relationship between zonal flows and confinement is strongly encouraged as cross-device activity including low temperature toroidal and linear devices. (author)

  16. Toroidal transformer design program with application to inverter circuitry

    Science.gov (United States)

    Dayton, J. A., Jr.

    1972-01-01

    Estimates of temperature, weight, efficiency, regulation, and final dimensions are included in the output of the computer program for the design of transformers for use in the basic parallel inverter. The program, written in FORTRAN 4, selects a tape wound toroidal magnetic core and, taking temperature, materials, core geometry, skin depth, and ohmic losses into account, chooses the appropriate wire sizes and number of turns for the center tapped primary and single secondary coils. Using the program, 2- and 4-kilovolt-ampere transformers are designed for frequencies from 200 to 3200 Hz and the efficiency of a basic transistor inverter is estimated.

  17. Analytical solution of the toroidal constant tension solenoid

    International Nuclear Information System (INIS)

    Gralnick, S.L.; Tenney, F.H.

    1975-01-01

    The coil shape is determined by requiring that the curvature of the flexible conductor be proportional to the distance from the toroidal axis. The resulting second order differential equation for the coil coordinates can be integrated once but for the second and final integration no closed form has been found and the integration has been done numerically. This solution of this differential equation is analytical in terms of an absolutely and uniformly convergent infinite series. The series converges quite rapidly and in practice ignoring all but the first five terms of the series introduces an error of less than 2 percent

  18. Theory and application of maximum magnetic energy in toroidal plasmas

    International Nuclear Information System (INIS)

    Chu, T.K.

    1992-02-01

    The magnetic energy in an inductively driven steady-state toroidal plasma is a maximum for a given rate of dissipation of energy (Poynting flux). A purely resistive steady state of the piecewise force-free configuration, however, cannot exist, as the periodic removal of the excess poloidal flux and pressure, due to heating, ruptures the static equilibrium of the partitioning rational surfaces intermittently. The rupture necessitates a plasma with a negative q'/q (as in reverse field pinches and spheromaks) to have the same α in all its force-free regions and with a positive q'/q (as in tokamaks) to have centrally peaked α's

  19. Position indicating split toroid for the RACE experiment

    International Nuclear Information System (INIS)

    Hurst, B.; Folkman, K.

    2007-01-01

    Aspects of the recent reactor accelerator coupled experiments (RACE) carried out at University of Texas Nuclear Engineering Teaching Laboratory will be discussed. In particular, a compact instrument that allowed a continuous non-invasive means of determining the relative electron beam position was developed. The operation of the instrument is similar to an inductive current pick up toroid except that the core is sectioned radially, which allows spatial information to be derived from the induced voltages. Results of initial tests, both in beam and with a pulser, will be presented along with plans to optimize future designs

  20. Fluctuations and stability in the Advanced Toroidal Facility (ATF) torsatron

    International Nuclear Information System (INIS)

    Harris, J.H.; Charlton, L.A.; Bell, J.D.; Bigelow, T.S.; Carreras, B.A.; Colchin, R.J.; Crume, E.C.; Dominguez, N.; Dunlap, J.L.; Dyer, G.R.; England, A.C.; Glowienka, J.C.; Hillis, D.L.; Hiroe, S.; Horton, L.D.; Howe, H.C.; Isler, R.C.; Jernigan, T.C.; Leboeuf, J.N.; Lee, D.K.; Lynch, V.E.; Lyon, J.F.; Menon, M.M.; Murakami, M.; Rasmussen, D.A.; Uckan, T.; Wilgen, J.B.; Wing, W.R.; Bell, G.L.; Crocker, N.A.; Hanson, G.R.; Thomas, C.E.; Wade, M.R.; Ritz, C.P.

    1990-01-01

    We present the results of experimental and theoretical studies of fluctuations and instabilities in the ATF torsatron, a type of stellarator. Measurements of globally coherent magnetic fluctuations in high-β plasmas with narrow pressure profiles produced by a field error show evidence of self-stabilization ('second stability'); the trends are compatible with theoretical analysis of self-stabilization of resistive curvature-driven instabilities, but there are discrepancies between the absolute experimental and theoretical fluctuation amplitudes. Fluctuation measurements in plasma with broad pressure profiles reveal new phenomena--specifically, toroidally localized magnetic fluctuations, whose amplitudes increase with plasma pressure, and coherent density fluctuations with significant radial width

  1. Atomic physics effects on dissipative toroidal drift wave stability

    International Nuclear Information System (INIS)

    Beer, M.A.; Hahm, T.S.

    1992-02-01

    The effects of atomic physics processes such as ionization, charge exchange, and radiation on the linear stability of dissipative drift waves are investigated in toroidal geometry both numerically and analytically. For typical TFTR and TEXT edge parameters, overall linear stability is determined by the competition between the destabilizing influence of ionization and the stabilizing effect due to the electron temperature gradient. An analytical expression for the linear marginal stability condition, η e crit , is derived. The instability is most likely to occur at the extreme edge of tokamaks with a significant ionization source and a steep electron density gradient

  2. System design of toroidal field power supply of CDD tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zheng Zhi

    1996-12-01

    This report deals with system design of Toroidal Field Power Supply of CDD tokamak (CDD-TFPS). The general design philosophy and design variations are introduced. After the outline of CDD-TFPS, the short-circuit calculation, the evaluation of converter parameters, the compatibility of converter and line are carried out. the specifications of major components, semi-conductor devices and accessories are given. High attention is paid to protection system. The design of sub-control and grounding system are described too. Some more general material for power supply design are attached in appendices for reference. (author). 30 tabs., 21 figs.

  3. Components and system tests on the RFX toroidal power supply

    International Nuclear Information System (INIS)

    Toigo, V.; Zanotto, L.; Gaio, E.; Perna, M.; Bordignon, P.; Coffetti, A.; Novaro, R.; Bertolotto, P.; Rinaldi, E.; Villa, G.

    2005-01-01

    The paper deals with the component and system tests performed on the new toroidal power supply system of the RFX experiment. The high technological innovation of the system required a deep experimental characterization and validation campaign; special factory tests were performed on prototypes of single components aimed at verifying the most critical design aspects. Consequently an articulated series of tests were performed, based on a step-by-step approach to achieve the desired coordinate operation of the whole system. The test procedures and the most significant results are described in the paper

  4. Toroidal mesoporous silica nanoparticles (TMSNPs) and related protocells

    Energy Technology Data Exchange (ETDEWEB)

    Brinker, C. Jeffrey; Lin, Yu-Shen

    2018-01-02

    In one aspect, the invention provides novel monodisperse, colloidally-stable, toroidal mesoporous silica nanoparticles (TMSNPs) which are synthesized from ellipsoid-shaped mesoporous silica nanoparticles (MSNPs) which are prepared using an ammonia basecatalyzed method under a low surfactant conditions. Significantly, the TMSNPs can be loaded simultaneously with a small molecule active agent, a siRNA, a mRNA, a plasmid and other cargo and can be used in the diagnosis and/or treatment of a variety of disorders, including a cancer, a bacterial infection and/or a viral infection, among others. Related protocells, pharmaceutical compositions and therapeutic and diagnostic methods are also provided.

  5. Nonlinear hybrid simulation of toroidicity-induced alfven eigenmode

    International Nuclear Information System (INIS)

    Fu, G.Y.; Park, W.

    1994-11-01

    Gyrokinetic/Magnetohydrodynamics hybrid simulations have been carried out using MH3D-K code to study the nonlinear saturation of the toroidicity-induced Alfven eigenmode driven by energetic particles in a tokamak plasma. It is shown that the wave particle trapping is the nonlinear saturation mechanism for the parameters considered. The corresponding density profile flattening of hot particles is observed. The saturation amplitude is proportional to the square of linear growth rate. In addition to TAE modes, a new n = 1, m = 0 global Alfven eigenmode is shown to be excited by the energetic particles

  6. Coupling to fast MHD eigenmodes in a toroidal cavity

    International Nuclear Information System (INIS)

    Paoloni, F.J.

    1975-05-01

    The coupling to fast MHD waves in toroidal-like geometry is calculated when eigenmodes exist in the plasma. The torus is considered to be a resonant cavity into which energy is coupled by a half turn loop. The cavity Q is calculated for the minority heating process, for cyclotron harmonic damping, electron transit-time magnetic pumping, wall loading, and Coulomb collisional damping. The problem of sustaining the eigenmode as the plasma conditions change with time is also discussed. One method that seems to be practical is a feedback scheme that varies the plasma major radius by a small amount as the conditions change. (U.S.)

  7. Acquisition system for the diagnostics data from a toroidal machine

    International Nuclear Information System (INIS)

    Moulin, B.

    1976-01-01

    The data acquisition system 'ARIANE' has been conceived by the SIG (Service d'Ionique Generale), for physical measurements on the toroidal machines PETULA and WEGA, which were designed to study the H.F. heating of pulsed plasmas. These systems are constitued of electronic modules which permit them to be adapted to different kinds of measurements, either by analogue channels or by pulse counting. The programmation of these systems, are achieved, either by multiswitches accessible manually on front panels, or by a computer which performs the numerical computations [fr

  8. Implications of polarized DT plasmas for toroidal fusion reactors

    International Nuclear Information System (INIS)

    Micklich, B.J.; Jassby, D.L.

    1983-05-01

    Spin polarization of the deuterons and tritons in a reacting plasma can result in an increase in the fusion reactivity and variation of the angular distribution of emission of the fusion neutrons. The increased fusion reactivity relaxes the confinement-temperature conditions for breakeven and ignition. We have determined the effect of varying the angular distribution of the fusion neutrons on the spatial distribution of fusion neturon current and flux at the first wall, on the global tritium breeding ratio, and on the first-wall radiation damage in low-aspect-ratio toroidal geometry

  9. Stochastic Generalized Method of Moments

    KAUST Repository

    Yin, Guosheng

    2011-08-16

    The generalized method of moments (GMM) is a very popular estimation and inference procedure based on moment conditions. When likelihood-based methods are difficult to implement, one can often derive various moment conditions and construct the GMM objective function. However, minimization of the objective function in the GMM may be challenging, especially over a large parameter space. Due to the special structure of the GMM, we propose a new sampling-based algorithm, the stochastic GMM sampler, which replaces the multivariate minimization problem by a series of conditional sampling procedures. We develop the theoretical properties of the proposed iterative Monte Carlo method, and demonstrate its superior performance over other GMM estimation procedures in simulation studies. As an illustration, we apply the stochastic GMM sampler to a Medfly life longevity study. Supplemental materials for the article are available online. © 2011 American Statistical Association.

  10. Characterizing flow fluctuations with moments

    Directory of Open Access Journals (Sweden)

    Rajeev S. Bhalerao

    2015-03-01

    Full Text Available We present a complete set of multiparticle correlation observables for ultrarelativistic heavy-ion collisions. These include moments of the distribution of the anisotropic flow in a single harmonic and also mixed moments, which contain the information on correlations between event planes of different harmonics. We explain how all these moments can be measured using just two symmetric subevents separated by a rapidity gap. This presents a multi-pronged probe of the physics of flow fluctuations. For instance, it allows to test the hypothesis that event-plane correlations are generated by non-linear hydrodynamic response. We illustrate the method with simulations of events in A MultiPhase Transport (AMPT model.

  11. Compact toroid injection system for JFT-2M

    Energy Technology Data Exchange (ETDEWEB)

    Fukumoto, N. [University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280 (Japan)]. E-mail: fukumotn@eng.u-hyogo.ac.jp; Ogawa, H. [Japan Atomic Energy Agency (JAEA), 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan); Nagata, M. [University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280 (Japan); Uyama, T. [University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280 (Japan); Shibata, T. [Japan Atomic Energy Agency (JAEA), 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan); Kashiwa, Y. [Japan Atomic Energy Agency (JAEA), 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan); Suzuki, S. [Japan Atomic Energy Agency (JAEA), 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan); Kusama, Y. [Japan Atomic Energy Agency (JAEA), 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan)

    2006-11-15

    The compact toroid (CT) injection system for JFT-2M is composed of a CT injector, a gas delivery and vacuum system, a power supply system, and a diagnostics system. In particular, the power supply system delivers high performance for CT formation and acceleration. The CT formation capacitor bank unit achieved a formation current of 350 kA with a rise time less than 10 {mu}s. Although the CT acceleration bank units are equipped with 14 ignitron switches instead of gap switches to attenuate the discharge noise level, an acceleration current of 400 kA with a short rise time of 9 {mu}s is controlled within a jitter of much less than 1 {mu}s. The resulting CT velocity and mass density satisfy the requirements for CT penetration into the tokamak plasma core at a toroidal field of 1 T. This CT injection system is thus suitable for CT injection in a middle-sized tokamak plasma such as the JFT-2M tokamak.

  12. Pareto optimal design of sectored toroidal superconducting magnet for SMES

    International Nuclear Information System (INIS)

    Bhunia, Uttam; Saha, Subimal; Chakrabarti, Alok

    2014-01-01

    Highlights: • The optimization approach minimizes both the magnet size and necessary cable length of a sectored toroidal SMES unit. • Design approach is suitable for low temperature superconducting cable suitable for medium size SMES unit. • It investigates coil parameters with respect to practical engineering aspects. - Abstract: A novel multi-objective optimization design approach for sectored toroidal superconducting magnetic energy storage coil has been developed considering the practical engineering constraints. The objectives include the minimization of necessary superconductor length and torus overall size or volume, which determines a significant part of cost towards realization of SMES. The best trade-off between the necessary conductor length for winding and magnet overall size is achieved in the Pareto-optimal solutions, the compact magnet size leads to increase in required superconducting cable length or vice versa The final choice among Pareto optimal configurations can be done in relation to other issues such as AC loss during transient operation, stray magnetic field at outside the coil assembly, and available discharge period, which is not considered in the optimization process. The proposed design approach is adapted for a 4.5 MJ/1 MW SMES system using low temperature niobium–titanium based Rutherford type cable. Furthermore, the validity of the representative Pareto solutions is confirmed by finite-element analysis (FEA) with a reasonably acceptable accuracy

  13. Influence of toroidal magnetic field in multi-accreting tori

    Science.gov (United States)

    Pugliese, D.; Montani, G.

    2018-02-01

    We analyzed the effects of a toroidal magnetic field in the formation of several magnetized accretion tori, dubbed as ringed accretion disks (RADs), orbiting around one central Kerr supermassive Black Hole (SMBH) in AGNs, where both corotating and counterotating disks are considered. Constraints on tori formation and emergence of RADs instabilities, accretion onto the central attractor and tori collision emergence, are investigated. The results of this analysis show that the role of the central BH spin-mass ratio, the magnetic field and the relative fluid rotation and tori rotation with respect the central BH, are crucial elements in determining the accretion tori features, providing ultimately evidence of a strict correlation between SMBH spin, fluid rotation and magnetic fields in RADs formation and evolution. More specifically we proved that magnetic field and disks rotation are in fact strongly constrained, as tori formation and evolution in RADs depend on the toroidal magnetic fields parameters. Eventually this analysis identifies specific classes of tori, for restrict ranges of magnetic field parameter, that can be observed around some specific SMBHs identified by their dimensionless spin.

  14. Studies of plasma self-organization in toroidal pinches

    International Nuclear Information System (INIS)

    Tamano, T.; Bard, W.D.; LaHaye, R.J.; Schaffer, M.J.; Taylor, P.L.

    1987-01-01

    Plasma self-organizations of toroidal pinch plasmas were observed in the OHTE device. The reversed field pinch discharges were sustained for about 15 ms longer than the shell time constant of 1.5 ms although linear MHD theories predict that MHD instabilities grow on the resistive shell time scale. Detailed studies of MHD activities led to the discovery of a toroidally localized kink mode. The slinky mode is the result of the phase locking of several internal kink modes due to non-linear coupling, and plays an important role in achieving the Taylor relaxed state. This is described in the first part of this lecture. Such phase lockings were observed not only for poloidal mode number m = -1 modes, but also for m = 0 and m = 1 modes. This provides some insight into how a tangled discharge can be formed. Tangled discharge models have been discussed by Rusbridge and others. However, the models do not provide a clean picture. The introduction of localized plasma deformation due to phase locking gives a simplified view of a tangled discharge. This is discussed in the second part of this lecture. The third part of this lecture describes another interesting plasma self-organization observed in the ultra low q regime. The plasma tend to maintain a constant current and shows a ''staircase''-like current behavior. 9 refs., 10 figs

  15. Protection of toroidal field coils using multiple circuits

    International Nuclear Information System (INIS)

    Thome, R.J.; Langton, W.G.; Mann, W.R.; Pillsbury, R.D.; Tarrh, J.M.

    1983-01-01

    The protection of toroidal field (TF) coils using multiple circuits is described. The discharge of a single-circuit TF system is given for purposes of definition. Two-circuit TF systems are analyzed and the results presented analytically and graphically. Induced currents, maximum discharge voltages, and discharge time constants are compared to the single-circuit system. Three-circuit TF systems are analyzed. In addition to induced currents, maximum discharge voltages, and time constants, several different discharge scenarios are included. The impacts of having discharge rates versus final maximum coil temperatures as requirements are examined. The out-of-plane forces which occur in the three-circuit system are analyzed using an approximate model. The analysis of multiplecircuit TF systems is briefly described and results for a Toroidal Fusion Core Experiment (TFCX) scale device are given based on computer analysis. The advantages and disadvantages of using multiple-circuit systems are summarized and discussed. The primary disadvantages of multiple circuits are the increased circuit complexity and potential for out-of-plane forces. These are offset by the substantial reduction in maximum discharge voltages, as well as other design options which become available when using multiple circuits

  16. Last End Cap Toroid installation : The Pharaonic enterprise

    CERN Document Server

    Arnaud Foussat

    After the successful and impressive transport feat from Building 191 to Point 1 was carried out by the Friderici crew on 28th June, the second and last Toroid End Cap, ECT-C, was transferred into the surface building, SX1, on 2nd July. The ECT-C was installed in the ATLAS cavern on the C-side on 12th July. As the person responsible for the project, in my opinion, one of the crucial points of this project was to design all the tooling and installation sequences taking into account the building infrastructure dimensional constraints. View of the ECT installation tooling and preparation for the ECT-C descent into the ATLAS 80m-shaft by the ATLAS magnet group and DBS teams. The movement of the 240-ton magnet and 12-m diameter toroid end-cap was achieved in collaboration with SCALES, a subcontractor company, using a hydraulic gantry able to lower the ECT inside the shaft by 5m below the floor level . This allowed the DBS team to attach the end-cap with the 2 x 140 tons overhead crane and lower it onto the c...

  17. The toroidal field magnet concept of ASDEX Upgrade

    International Nuclear Information System (INIS)

    Jandl, O.; Kollotzek, H.; Springmann, E.; Streibl, B.

    1983-01-01

    ASDEX Upgrade (UG), a divertor tokamak with a minor plasma radius of a = 0.5 m and a plasma current of 1.2 to 1.5 MA, is intended to succeed ASDEX. A major target of this experiment is to investigate a reactor-compatible plasma boundary. This requires according to a toroidal field (B 0 ) at the plasma centre normalized to the aspect ratio (A) of B 0 /A approximately = 1.2. The optimum with due allowance for physical requirements and technical constraints of the complete tokamak system was obtained in this case for B 0 = 3.9 T (A = 3.25) and a plasma radius of 1.63 m. The toroidal field (TF) magnet designed to meet these requirements is presented. Aspects of its turnover structure such as force transfer, coil housing and access to the plasma vessel are described. The coil concept developed in collaboration with industry is also presented, in particular the conductor concept and the current terminals and water manifold designs. Finally, the results of the cooling and stress analysis are summarized. (author)

  18. Cryogenic Characteristics of the ATLAS Barrel Toroid Superconducting Magnet

    CERN Document Server

    Pengo, R; Delruelle, N; Pezzetti, M; Pirotte, O; Passardi, Giorgio; Dudarev, A; ten Kate, H

    2008-01-01

    ATLAS, one of the experiments of the LHC accelerator under commissioning at CERN, is equipped with a large superconducting magnet the Barrel Toroid (BT) that has been tested at nominal current (20500 A). The BT is composed of eight race-track superconducting coils (each one weights about 45 tons) forming the biggest air core toroidal magnet ever built. By means of a large throughput centrifugal pump, a forced flow (about 10 liter/second at 4.5 K) provides the indirect cooling of the coils in parallel. The paper describes the results of the measurements carried out on the complete cryogenic system assembled in the ATLAS cavern situated 100 m below the ground level. The measurements include, among other ones, the static heat loads, i.e., with no or constant current in the magnet, and the dynamic ones, since additional heat losses are produced, during the current ramp-up or slow dump, by eddy currents induced on the coil casing.

  19. Advanced transport modeling of toroidal plasmas with transport barriers

    International Nuclear Information System (INIS)

    Fukuyama, A.; Murakami, S.; Honda, M.; Izumi, Y.; Yagi, M.; Nakajima, N.; Nakamura, Y.; Ozeki, T.

    2005-01-01

    Transport modeling of toroidal plasmas is one of the most important issue to predict time evolution of burning plasmas and to develop control schemes in reactor plasmas. In order to describe the plasma rotation and rapid transition self-consistently, we have developed an advanced scheme of transport modeling based on dynamical transport equation and applied it to the analysis of transport barrier formation. First we propose a new transport model and examine its behavior by the use of conventional diffusive transport equation. This model includes the electrostatic toroidal ITG mode and the electromagnetic ballooning mode and successfully describes the formation of internal transport barriers. Then the dynamical transport equation is introduced to describe the plasma rotation and the radial electric field self-consistently. The formation of edge transport barriers is systematically studied and compared with experimental observations. The possibility of kinetic transport modeling in velocity space is also examined. Finally the modular structure of integrated modeling code for tokamaks and helical systems is discussed. (author)

  20. Photoelastic analyses of stresses in toroidal magnetic field coils

    International Nuclear Information System (INIS)

    Pih, H.

    1977-02-01

    Several two-dimensional photoelastic stress analyses were made on models of circular and oval toroidal magnetic field coils for fusion reactors. The circumferential variation of each coil's in-plane magnetic force was simulated by applying different pressures to 16 segmented regions of the inner surface of the models. One special loading fixture was used for the model of each shape and size. Birefringence and isoclinic angles were measured in a transmission polariscope at selected points on the loaded model. Boundary stresses in the cases of known boundary conditions were determined directly from the isochromatics. Separate principal stresses were calculated using the combination of photoelastic information and isopachic data obtained by the electrical analogy method from the solution of Laplace's equation. Comparisons were made between experimental results and those computed using the finite element method. The stress distribution between theoretical and experimental agrees very well, although the finite element method yielded slightly higher stresses than the photoelastic method; further work is needed to resolve this difference. In this investigation several variations of coil geometry and methods of support were evaluated. Based on experimental results, optimum structural designs of toroidal field coils were recommended

  1. Method of moments in electromagnetics

    CERN Document Server

    Gibson, Walton C

    2007-01-01

    Responding to the need for a clear, up-to-date introduction to the field, The Method of Moments in Electromagnetics explores surface integral equations in electromagnetics and presents their numerical solution using the method of moments (MOM) technique. It provides the numerical implementation aspects at a nuts-and-bolts level while discussing integral equations and electromagnetic theory at a higher level. The author covers a range of topics in this area, from the initial underpinnings of the MOM to its current applications. He first reviews the frequency-domain electromagnetic theory and t

  2. Toroidal hollow-core microcavities produced by self-rolling of strained polymer bilayer films

    Science.gov (United States)

    Luchnikov, V.; Kumar, K.; Stamm, M.

    2008-03-01

    Hollow-core toroidal micro-cavities are obtained by self-rolling of double-layer (polyvinyl pyridine/polystyrole) polymer films. Rolling of the bilayer is due to preferential swelling of polyvinyl pyridine in water solution of dodecyl benzene sulfonic acid. The tube formation proceeds from a circular opening in the film made by photolithography or by mechanical scratching. Toroid equilibrium dimensions are determined by the balance of the elastic energy relaxation via the film scrolling and the work of the in-plane stretching that is due to increasing radius of the toroid. The principle features of the micro-toroid formation process are captured by a simple analytical model. The inner walls of the cavities can be made metal coated. For this aim, the polymer bilayer can be metallized by vacuum sputtering prior to lithographic patterning and rolling of the bilayer. The toroids with metallic inner surfaces are promising for the future research as IR-frequency range resonators.

  3. Quiet Moment around the Campfire

    Centers for Disease Control (CDC) Podcasts

    2014-06-18

    Byron Breedlove reads his essay, "Quiet Moment around the Campfire," about the art of Frederic Remington and the transmission of pathogens as frontiers expand.  Created: 6/18/2014 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 6/19/2014.

  4. Updating neutrino magnetic moment constraints

    Directory of Open Access Journals (Sweden)

    B.C. Cañas

    2016-02-01

    Full Text Available In this paper we provide an updated analysis of the neutrino magnetic moments (NMMs, discussing both the constraints on the magnitudes of the three transition moments Λi and the role of the CP violating phases present both in the mixing matrix and in the NMM matrix. The scattering of solar neutrinos off electrons in Borexino provides the most stringent restrictions, due to its robust statistics and the low energies observed, below 1 MeV. Our new limit on the effective neutrino magnetic moment which follows from the most recent Borexino data is 3.1×10−11μB at 90% C.L. This corresponds to the individual transition magnetic moment constraints: |Λ1|≤5.6×10−11μB, |Λ2|≤4.0×10−11μB, and |Λ3|≤3.1×10−11μB (90% C.L., irrespective of any complex phase. Indeed, the incoherent admixture of neutrino mass eigenstates present in the solar flux makes Borexino insensitive to the Majorana phases present in the NMM matrix. For this reason we also provide a global analysis including the case of reactor and accelerator neutrino sources, presenting the resulting constraints for different values of the relevant CP phases. Improved reactor and accelerator neutrino experiments will be needed in order to underpin the full profile of the neutrino electromagnetic properties.

  5. Moment methods and Lanczos methods

    International Nuclear Information System (INIS)

    Whitehead, R.R.

    1980-01-01

    In contrast to many of the speakers at this conference I am less interested in average properties of nuclei than in detailed spectroscopy. I will try to show, however, that the two are very closely connected and that shell-model calculations may be used to give a great deal of information not normally associated with the shell-model. It has been demonstrated clearly to us that the level spacing fluctuations in nuclear spectra convey very little physical information. This is true when the fluctuations are averaged over the entire spectrum but not if one's interest is in the lowest few states, whose spacings are relatively large. If one wishes to calculate a ground state (say) accurately, that is with an error much smaller than the excitation energy of the first excited state, very high moments, μ/sub n/, n approx. 200, are needed. As I shall show, we use such moments as a matter of course, albeit without actually calculating them; in fact I will try to show that, if at all possible, the actual calculations of moments is to be avoided like the plague. At the heart of the new shell-model methods embodied in the Glasgow shell-model program and one or two similar ones is the so-called Lanczos method and this, it turns out, has many deep and subtle connections with the mathematical theory of moments. It is these connections that I will explore here

  6. Moment Invariants in Image Analysis

    Czech Academy of Sciences Publication Activity Database

    Flusser, Jan

    2006-01-01

    Roč. 11, č. 2 (2006), s. 196-201 ISSN 1305-5313 R&D Projects: GA MŠk 1M0572; GA ČR GA102/04/0155 Institutional research plan: CEZ:AV0Z10750506 Keywords : moment invariants * pattern recognition Subject RIV: JD - Computer Applications, Robotics

  7. Face recognition using Krawtchouk moment

    Indian Academy of Sciences (India)

    Artificial Intelligence 17(1): 41–62. Hu M K 1962 Visual pattern recognition by moment invariants. IRE Trans. on Information Theory, IT-8,. 179–187. Huang F T, Zhou Z, Zhang H-J and Chen T 2000 Pose invariant face recognition, Proc. Fourth IEEE. International Conference on Automatic Face and Gesture Recognition, ...

  8. Particle electric dipole-moments

    Energy Technology Data Exchange (ETDEWEB)

    Pendlebury, J.M. [Sussex Univ., Brighton (United Kingdom)

    1997-04-01

    The incentive to detect particle electric dipole-moments, as a window on time-reversal violation, remains undiminished. Efforts to improve the measurements for the neutron, the electron and some nuclei are still making rapid progress as more powerful experimental methods are brought to bear. A new measurement for the neutron at ILL is presented. (author). 7 refs.

  9. Slow magnetic relaxation and single-molecule toroidal behaviour in a family of heptanuclear {Cr"I"I"ILn"I"I"I_6} (Ln=Tb, Ho, Er) complexes

    Energy Technology Data Exchange (ETDEWEB)

    Vignesh, Kuduva R. [IITB-Monash Research Academy, IIT Bombay, Powai, Mumbai (India); Langley, Stuart K. [School of Science and the Environment, Division of Chemistry, Manchester Metropolitan University, Manchester (United Kingdom); Swain, Abinash; Rajaraman, Gopalan [Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai (India); Moubaraki, Boujemaa; Murray, Keith S. [School of Chemistry, Monash University, Clayton, VIC (Australia); Damjanovic, Marko; Wernsdorfer, Wolfgang [Institute Neel, CNRS, Universite Grenoble Alpes, Grenoble (France); Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen (Germany)

    2018-01-15

    The synthesis, magnetic properties, and theoretical studies of three heterometallic {Cr"I"I"ILn"I"I"I_6} (Ln=Tb, Ho, Er) complexes, each containing a metal topology consisting of two Ln{sub 3} triangles connected via a Cr{sup III} linker, are reported. The {CrTb_6} and {CrEr_6} analogues display slow relaxation of magnetization in a 3000 Oe static magnetic field. Single-crystal measurements reveal opening up of the hysteresis loop for {CrTb_6} and {CrHo_6} molecules at low temperatures. Ab initio calculations predict toroidal magnetic moments in the two Ln{sub 3} triangles, which are found to couple, stabilizing a con-rotating ferrotoroidal ground state in Tb and Ho examples and extend the possibility of observing toroidal behaviour in non Dy{sup III} complexes for the first time. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Proceedings of the third symposium on the physics and technology of compact toroids in the magnetic fusion energy program

    International Nuclear Information System (INIS)

    Siemon, R.E.

    1981-03-01

    This document contains papers contributed by the participants of the Third Symposium on Physics and Technology of Compact Toroids in the Magnetic Fusion Energy Program. Subjects include reactor aspects of compact toroids, energetic particle rings, spheromak configurations (a mixture of toroidal and poloidal fields), and field-reversed configurations

  11. ALT-II toroidal belt pump limiter performance in TEXTOR

    Energy Technology Data Exchange (ETDEWEB)

    Goebel, D.M.; Conn, R.W.; Corbett, W.J.; Moyer, R.; Dippel, K.H.; Finken, K.H.; Hardtke, A.; Kohlhaas, W.; Wolf, G.; Gauster, W.B.

    1989-04-01

    The Advanced Limiter Test (ALT-II) is a toroidal belt pump limiter in the TEXTOR tokamak. ALT-II is composed of 8 blade segments which form an axisymmetric toroidal belt of 3.4 m/sup 2/ exposed surface area, located on the outside of the torus at 45/sup 0/ below the horizontal midplane. Ohmic plasma operation with ALT-II as the main limiter is characterized by a line-averaged density range of 5x10/sup 12/ to 5.5x10/sup 13/ cm/sup -3/ at B/sub T/=2 T and I/sub p/=340 kA, Z/sub eff/=1.1 to 2 and typically 40 to 95% of the power radiated depending on the plasma density. ICRH heating of the plasma with up to 2.6 MW of incident power has been achieved, which modifies the scrape-off layer (SOL) and the pump limiter performance. The recycling coefficient in TEXTOR is normally close to one, but helium RG conditioning and baking of the limiter at 400/sup 0/C is found to lower the recycling coefficient to 0.8 for the order of 10 shots. Measurements by arrays of probes in the SOL and thermocouples in the limiter tiles indicate the flow to the limiter is toroidally symmetric and poloidally asymmetric. The asymmetries result in different power and particle fluxes to the ion and electron drift sides of the limiter. The density and power scrape-off lengths are on the order of 1 cm and significantly longer on the outside of the torus. In spite of the flow asymmetry favoring the ion drift side near the tangency point, the longer e-folding lengths on the electron side in the SOL result in equal or higher particle collection by the electron side. The probe arrays indicate that during ohmic heating a total of 15 to 20% of the core efflux is incident on the neutralizer plates located in scoops beneath the blades. More particles are collected during ICRH auxiliary heating due to changes in the SOL profiles and shorter particle confinement times. (Abstract Truncated)

  12. Instability of Toroidal Magnetic Field in Jets and Plerions

    Science.gov (United States)

    Begelman, Mitchell C.

    1998-01-01

    Astrophysical jets and pulsar-fed supernova remnants (plerions) are expected to develop highly organized magnetic structures dominated by concentric loops of toroidal field, Bφ. It has been argued that such structures could explain the polarization properties of some jets and contribute to their lateral confinement through magnetic tension forces. A concentric toroidal field geometry is also central to the Rees-Gunn model for the Crab Nebula, the archetypal plerion, and leads to the deduction that the Crab pulsar's wind must have a weak magnetic field. Yet this kind of equilibrium between magnetic and gas pressure forces, the ``equilibrium Z-pinch'' of the controlled fusion literature, is well known to be susceptible to disruptive localized instabilities, even when the magnetic field is weak and/or boundary conditions (e.g., a dense external medium) slow or suppress global modes. Thus, the magnetic field structures imputed to the interiors of jets and plerions are unlikely to persist for very long. To determine the growth rates of Z-pinch instabilities under astrophysical conditions, I derive a dispersion relation that is valid for the relativistic fluids of which jets and plerions may be composed, in the ideal magnetohydrodynamics (MHD) limit. The dominant instabilities are kink (m = 1) and pinch (m = 0) modes. The former generally dominate, destroying the concentric field structure and probably driving the system toward a more chaotic state in which the mean field strength is independent of radius (and in which resistive dissipation of the field may be enhanced). I estimate the timescales over which the field structure is likely to be rearranged and relate these to distances along relativistic jets and radii from the central pulsar in a plerion. I conclude that the central tenet of the Rees-Gunn model for the Crab Nebula, the existence of a concentric toroidal field well outside the pulsar wind's termination shock, is physically unrealistic. With this assumption

  13. Toroidal and poloidal momentum transport studies in tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Tala, T [Association EURATOM-Tekes, VTT, PO Box 1000, FIN-02044 VTT (Finland); Crombe, K [Department of Applied Physics, Ghent University (Belgium); Vries, P C de [EURATOM/UKAEA Fusion Association, Culham Science Centre, Oxon, OX14 3DB (United Kingdom)] (and others)

    2007-12-15

    The present status of understanding of toroidal and poloidal momentum transport in tokamaks is presented in this paper. Similar energy confinement and momentum confinement times, i.e. {tau}{sub E}/{tau}{sub {phi}} {approx} 1 have been reported on several tokamaks. It is more important though, to study the local transport both in the core and edge plasma separately as, for example, in the core plasma, a large scatter in the ratio of the local effective momentum diffusivity to the ion heat diffusivity {chi}{sub {phi}}{sub eff}/{chi}{sub i,eff} among different tokamaks can be found. For example, the value of effective Prandtl number is typically around {chi}{sub {phi}}{sub eff}/{chi}{sub i,eff} {approx} 0.2 on JET while still {tau}{sub E}/{tau}{sub {phi}} {approx} 1 holds. Perturbative NBI modulation experiments on JET have shown, however, that a Prandtl number {chi}{sub {phi}}{sub /}{chi}{sub i} of around 1 is valid if there is an additional, significant inward momentum pinch which is required to explain the amplitude and phase behaviour of the momentum perturbation. The experimental results, i.e. the high Prandtl number and pinch, are in good qualitative and to some extent also in quantitative agreement with linear gyro-kinetic simulations. In contrast to the toroidal momentum transport which is clearly anomalous, the poloidal velocity is usually believed to be neo-classical. However, experimental measurements on JET show that the carbon poloidal velocity can be an order of magnitude above the predicted value by the neo-classical theory within the ITB. These large measured poloidal velocities, employed for example in transport simulations, significantly affect the calculated radial electric field and therefore the E x B flow shear and hence modify and can significantly improve the simulation predictions. Several fluid turbulence codes have been used to identify the mechanism driving the poloidal velocity to such high values. CUTIE and TRB turbulence codes and also

  14. Toroidal and poloidal momentum transport studies in tokamaks

    Science.gov (United States)

    Tala, T.; Crombé, K.; de Vries, P. C.; Ferreira, J.; Mantica, P.; Peeters, A. G.; Andrew, Y.; Budny, R.; Corrigan, G.; Eriksson, A.; Garbet, X.; Giroud, C.; Hua, M.-D.; Nordman, H.; Naulin, V.; Nave, M. F. F.; Parail, V.; Rantamäki, K.; Scott, B. D.; Strand, P.; Tardini, G.; Thyagaraja, A.; Weiland, J.; Zastrow, K.-D.; Contributors, JET-EFDA

    2007-12-01

    The present status of understanding of toroidal and poloidal momentum transport in tokamaks is presented in this paper. Similar energy confinement and momentum confinement times, i.e. τE/τphi ≈ 1 have been reported on several tokamaks. It is more important though, to study the local transport both in the core and edge plasma separately as, for example, in the core plasma, a large scatter in the ratio of the local effective momentum diffusivity to the ion heat diffusivity χphieff/χi,eff among different tokamaks can be found. For example, the value of effective Prandtl number is typically around χphieff/χi,eff ≈ 0.2 on JET while still τE/τphi ≈ 1 holds. Perturbative NBI modulation experiments on JET have shown, however, that a Prandtl number χphi/χi of around 1 is valid if there is an additional, significant inward momentum pinch which is required to explain the amplitude and phase behaviour of the momentum perturbation. The experimental results, i.e. the high Prandtl number and pinch, are in good qualitative and to some extent also in quantitative agreement with linear gyro-kinetic simulations. In contrast to the toroidal momentum transport which is clearly anomalous, the poloidal velocity is usually believed to be neo-classical. However, experimental measurements on JET show that the carbon poloidal velocity can be an order of magnitude above the predicted value by the neo-classical theory within the ITB. These large measured poloidal velocities, employed for example in transport simulations, significantly affect the calculated radial electric field and therefore the E × B flow shear and hence modify and can significantly improve the simulation predictions. Several fluid turbulence codes have been used to identify the mechanism driving the poloidal velocity to such high values. CUTIE and TRB turbulence codes and also the Weiland model predict the existence of an anomalous poloidal velocity, peaking in the vicinity of the ITB and driven dominantly

  15. Maximal Electric Dipole Moments of Nuclei with Enhanced Schiff Moments

    CERN Document Server

    Ellis, John; Pilaftsis, Apostolos

    2011-01-01

    The electric dipole moments (EDMs) of heavy nuclei, such as 199Hg, 225Ra and 211Rn, can be enhanced by the Schiff moments induced by the presence of nearby parity-doublet states. Working within the framework of the maximally CP-violating and minimally flavour-violating (MCPMFV) version of the MSSM, we discuss the maximal values that such EDMs might attain, given the existing experimental constraints on the Thallium, neutron and Mercury EDMs. The maximal EDM values of the heavy nuclei are obtained with the help of a differential-geometrical approach proposed recently that enables the maxima of new CP-violating observables to be calculated exactly in the linear approximation. In the case of 225Ra, we find that its EDM may be as large as 6 to 50 x 10^{-27} e.cm.

  16. Commercial tokamak reactors with resistive toroidal field magnets

    International Nuclear Information System (INIS)

    Bombery, L.; Cohn, D.R.; Jassby, D.L.

    1984-01-01

    Scaling relations and design concepts are developed for commercial tokamak reactors that use watercooled copper toroidal field (TF) magnets. Illustrative parameters are developed for reactors that are scaled up in size from LITE test reactor designs, which use quasi-continuous copper plate magnets. Acceptably low magnet power requirements may be attainable in a moderate beta (β = 0.065) commercial reactor with a major radius of 6.2 m. The shielding thickness and magnet size are substantially reduced relative to values in commercial reactors with superconducting magnets. Operation at high beta (β = 0.14) leads to a reduction in reactor size, magnet-stored energy, and recirculating power. Reactors using resistive TF magnets could provide advantages of physically smaller devices, improved maintenance features, and increased ruggedness and reliability

  17. Ballooning instabilities in tokamaks with sheared toroidal flows

    International Nuclear Information System (INIS)

    Waelbroeck, F.L.; Chen, L.

    1990-11-01

    The stability of ballooning modes in the presence of sheared toroidal flows is investigated. The eigenmodes are shown to be related by a Fourier transformation to the non-exponentially growing Floquet solutions found by Cooper. It is further shown that the problem cannot be reduced further than to a two dimensional partial differential equation. Next, the generalized ballooning equation is solved analytically for a circular tokamak equilibrium with sonic flows, but with a small rotation shear compared to the sound speed. With this ordering, the centrifugal forces are comparable to the pressure gradient forces driving the instability, but coupling of the mode with the sound wave is avoided. A new stability criterion is derived which explicitly demonstrates that flow shear is stabilizing at constant centrifugal force gradient. 34 refs

  18. Fabrication of the KSTAR toroidal field coil structure

    International Nuclear Information System (INIS)

    Choi, C.H.; Sa, J.W.; Park, H.K.; Hong, K.H.; Shin, H.; Kim, H.T.; Bak, J.S.; Lee, G.S.; Kwak, J.H.; Moon, H.G.; Yoon, H.H.; Lee, J.W.; Lee, S.K.; Song, J.Y.; Nam, K.M.; Byun, S.E.; Kim, H.C.; Ha, E.T.; Ahn, H.J.; Kim, D.S.; Lee, J.S.; Park, K.H.; Hong, C.D.

    2005-01-01

    The KSTAR toroidal field (TF) coil structure is under fabrication upon completion of engineering design and prototype construction. The prototype TF coil structure has been fabricated within allowable tolerances. Encasing of the prototype TF coil (TF00) in the prototype structure has been carried out through major processes involving a coil encasing, an enclosing weld, a vacuum pressure impregnation, and an outer surface machining. During the enclosing weld of the TF00 coil structure, we have measured temperatures and stresses on the coil surface. Assembly test had been performed with the TF00 coil structure. We have chosen Type 316LN as material of the TF coil structure. We used the narrow-gap TIG welding method. Doosan Heavy Industries and Construction Company (DHI) will complete the fabrication of the TF coil structure in Feb. 2006. (author)

  19. MHD Stability of Free Boundary Toroidal Z Pinch

    Science.gov (United States)

    Sugisaki, Kiwamu

    1990-06-01

    The Magnetohydrodynamic (MHD) stability of a free boundary toroidal Z pinch plasma is investigated. Equilibrium field profiles are chosen so that μ is nearly uniform in the central region, μ and dμ/dr vanish on the boundary and Suydam’s criterion is satisfied throughout the plasma. The stability of the equilibrium is examined for the ratio b of the conducting wall radius to the plasma radius and plasma pressure. The stability of non-resonant ideal modes is determined mainly from the safty factor on the axis. Non-resonant modes are dominant for low plasma pressure, whereas resonant modes are dominant for high plasma pressure. Tearing modes are stable only for b below 1.04. The width of the magnetic islands produced from the tearing modes is evaluated. As b increases, overlap of the magnetic islands occurs over a wide area in the plasma.

  20. Electron cyclotron heating and current drive in toroidal geometry

    Energy Technology Data Exchange (ETDEWEB)

    Kritz, A.H.

    1993-03-01

    The Principal Investigator has continued to work on problems associated both with the deposition and with the emission of electron cyclotron heating power electron cyclotron heating in toroidal plasmas. Inparticular, the work has focused on the use of electron cyclotron heating to stabilize q = 1 and q = 2 instabilities in tokamaks and on the use of electron cyclotron emission as a plasma diagnostic. The research described in this report has been carried out in collaboration with scientists at Princeton, MIT and Livermore. The Principal Investigator is now employed at Lehigh University, and a small group effort on electron cyclotron heating in plasmas has begun to evolve at Lehigh involving undergraduate and graduate students. Work has also been done in support of the electron cyclotron heating and current drive program at the Center for Research in Plasma Physics in Lausanne, Switzerland.

  1. Interactions of toroidally coupled tearing modes in the KSTAR tokamak

    Science.gov (United States)

    Kim, Gnan; Yun, Gunsu S.; Woo, Minho; Park, Hyeon K.; KSTAR team2, the

    2018-03-01

    The evolutions of toroidally coupled radially-distant and radially-adjacent tearing modes are visualized in 2D in detail on the Korea superconducting tokamak for advanced research. The coupled tearing modes are in-phase on the out-board mid-plane and become destabilized or compete with each other depending on their spatial separation. When two coupled tearing modes are far apart, both are increasingly destabilized. On the other hand, when they become close to each other, one becomes stabilized while the other becomes destabilized. In such cases, an additional tearing mode is often formed on outer rational flux surface and the three tearing modes compete. The competitions suggest that spatial overlap (merging) of coupled magnetic islands is difficult.

  2. Characteristics of toroidal energy deposition asymmetries in ASDEX

    International Nuclear Information System (INIS)

    Evans, T.E.; Neuhauser, J.; Leuterer, F.; Mueller, E.R.

    1990-01-01

    Large toroidal and poloidal asymmetries with characteristics which are sensitively dependent on q a , the vertical position of the plasma, and the type of additional heating are observed in the energy flow to the ASDEX divertor target plates. The largest asymmetries and total energy depositions are observed during lower hybrid wave injection experiments with approximately 50% of the input energy going to the combined divertor targets and shields. A maximum localized energy density loading of 10 MJ/m 2 is typical under these conditions. Measurements of the asymmetries are consistent with a model in which magnetic islands and ergodicity due to intrinsic magnetic perturbations dominate the energy transpot across the primary magnetic separatrix. The results emphasize the essential role of resonant magnetic perturbations in determining the performance of tokamaks and demonstrate that non-axisymmetric effects caused by small perturbations become increasingly important in determining the transport properties as the injected power is increased. (orig.)

  3. Effect of loss cone on confinement in toroidal helical device

    International Nuclear Information System (INIS)

    Itoh, K.; Itoh, S.-I.; Fukuyama, A.; Hanatani, K.

    1988-12-01

    Analytical estimation is given on the loss cone in the toroidal helical devices in the presence of the radial electric field and the modulation of the helical ripple. The minimum energy of particles entering the loss cone is calculated. The modulation is not always effective in reducing the loss in the presence of the radial electric field. The plasma loss due to the loss cone is estimated in the collisionless limit. The radial electric field is estimated in the presence of the loss cone. It is found that the transition to the solution with positive radial electric field, which is necessary to achieve the high-ion-temperature mode, becomes difficult. This difficulty is large for the systems with the small helical ripple. (author)

  4. Manufacturing aspects of toroidal field magnets for tokamak power reactors

    International Nuclear Information System (INIS)

    Smith, G.E.

    1977-01-01

    The manufacturing aspects of two different toroidal field (TF) coils are discussed briefly. The first of these is the Tokamak Fusion Test Reactor (TFTR) TF coil, which is presently in the design phase at the Princeton Plasma Physics Laboratory. The second coil configuration reflects a reference design for a large experimental power reactor (EPR) which originated at the Oak Ridge National Laboratory. This configuration was used by the Grumman Aerospace Corporation of Bethpage, N.Y. as the basis for an investigation of the manufacturing aspects of a large superconducting TF coil, the results of which are summarized. For each of these coils, the major characteristics of the design are first briefly described and the significant manufacturing aspects are then summarized

  5. Elastomer seal for a large toroidal vacuum chamber

    International Nuclear Information System (INIS)

    Skellett, S.; Casey, F.; Blake, H.

    1978-07-01

    An aluminium toroidal vacuum chamber for use at 10(-6) torr, whose overall diameter is in the region of 5 metres, was built from 4 component parts which resulted in joint lines in the horizontal and vertical planes crossing each other in 4 places. A viton seal was developed which allows a vacuum tight joint to be made without the need for tightly toleranced fitting of the mating faces and also overcomes the difficulty of ensuring a reliable seal at cross-over joints. Ease of maintenance and repair in situ are important factors of the design. An assembly which presented the geometry of the sealing problem was tested and is described here. Various adhesives for bonding viton were examined for the manufacture of the seal. The most suitable adhesive was found to be Loctite S496, chosen for its bond strength and convenience in use. A device for preparing and bonding the viton in situ is described. (author)

  6. Defects in an active nematic confined to a toroid

    Science.gov (United States)

    Ellis, Perry; Pearce, Dan; Giomi, Luca; Fernandez-Nieves, Alberto

    Active materials are driven far from the ground state by the motion of their constituent particles, thereby making them inherently non-equilibrium materials. For an active nematic, this results in a continuous creation and annihilation of +/- 1 / 2 defect pairs. Here, we confine an active nematic to the surface of a toroid and show that the topological charge of the defects couples to the Gaussian curvature of the underlying surface. However, in our experiments this defect unbinding happens on average, illustrating that despite subtle differences, the role of activity is reminiscent of the role of temperature in conventional nematics. This is confirmed by computer simulations which clearly illustrate that defect unbinding depends on activity. Overall, our results illustrate the role of confinement and curvature on the defect behavior of active nematic liquid crystals. PWE is supported by FLAMEL under Grant NSF 1258425.

  7. Manufacturing aspects of the ATLAS barrel toroid double pancakes

    CERN Document Server

    Drago, G; Gagliardi, P; Laurenti, A; Marabotto, R; Penco, R

    2002-01-01

    In 1999 INFN (Istituto Nazionale di Fisica Nucleare) ordered to ANSALDO the manufacturing of 16 double pancakes for the ATLAS BARREL TOROID. In July 2001 four Double Pancakes have already been completed and shipped to the integration site. In this paper the main aspects of the manufacturing of the largest superconducting coils ever built (5*25 m) are described. The main phases of the manufacturing procedure are reviewed starting from the conductor preparation to the VPI impregnation, including references to the materials used as well as to the relevant customer's requirements. In particular the special winding form and the winding technique are treated. For each phase the most critical aspects and the relevant solutions are pointed out. Particular details about the technical solutions adopted for the impregnation and curing of the Double Pancake, which could not be performed inside an autoclave due to the huge dimension of the coil itself, are reported. Finally the methods used for the dimensional and electri...

  8. First assembly phase for the ATLAS toroid coils

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    The ATLAS barrel toroid system consists of eight coils, each of axial length 25.3 m, assembled radially and symmetrically around the beam axis. The coils are of a flat racetrack type with two double-pancake windings made of 20.5 kA aluminium-stabilized niobium-titanium superconductor. In the first phase of assembly, the two 'pancakes' are packed into their vacuum vessel. This is done using bladders filled with resin and glass microbeads under pressure. The resin is heated and, once cooled, holds the pancakes in place. The operation has to be performed on both sides of the coil, which necessitated a special technique to turn the coils over and then transport them to the heating table. Photos 01, 02, 03: Transporting the coil to the heating table using a special lifting gantry manufactured at JINR-Dubna, Russia in preparation for the 'bladderisation' operation.

  9. Density Measurement of Compact Toroid with Mach-Zehnder Interferometer

    Science.gov (United States)

    Laufman-Wollitzer, Lauren; Endrizzi, Doug; Brookhart, Matt; Flanagan, Ken; Forest, Cary

    2016-10-01

    Utilizing a magnetized coaxial plasma gun (MCPG) built by Tri Alpha Energy, a dense compact toroid (CT) is created and injected at high speed into the Wisconsin Plasma Astrophysics Laboratory (WiPAL) vessel. A modified Mach-Zehnder interferometer from the Line-Tied Reconnection Experiment (LTRX) provides an absolute measurement of electron density. The interferometer is located such that the beam intersects the plasma across the diameter of the MCPG drift region before the CT enters the vessel. This placement ensures that the measurement is taken before the CT expand. Results presented will be used to further analyze characteristics of the CT. Funding provided by DoE, NSF, and WISE Summer Research.

  10. Overview, Progress, and Plans for the Compact Toroidal Hybrid Experiment

    Science.gov (United States)

    Hartwell, G. J.; Allen, N. R.; Ennis, D. A.; Hanson, J. D.; Howell, E. C.; Johnson, C. A.; Knowlton, S. F.; Kring, J. D.; Ma, X.; Maurer, D. A.; Ross, K. G.; Schmitt, J. C.; Traverso, P. J.; Williamson, E. N.

    2017-10-01

    The Compact Toroidal Hybrid (CTH) is an l = 2 , m = 5 torsatron/tokamak hybrid (R0 = 0.75 m, ap 0.2 m, and | B | plasma current for heating and disruption studies. The main goals of the CTH experiment are to study disruptive behavior as a function of applied 3D magnetic shaping, and to test and advance the V3FIT reconstruction code and NIMROD modeling of CTH. The disruptive density limit is observed to exceed the Greenwald limit as the vacuum transform is increased with no observed threshold for avoidance. Low-q operations (1.1 eliminate the vertical drift of elongated discharges. Internal SXR diagnostics, in conjunction with external magnetics, extend the range of reconstruction accuracy into the plasma core. This work is supported by U.S. Department of Energy Grant No. DE-FG02-00ER54610.

  11. Roles of electric field on toroidal magnetic confinement

    International Nuclear Information System (INIS)

    Itoh, Kimitaka; Itoh, Sanae; Sanuki, Heiji; Fukuyama, Atsushi.

    1992-11-01

    Theoretical research on the influence of the electric field on the toroidal magnetic confinement is surveyed. The static electric field is first described. Physics pictures on the generation of the radial electric field and the influence on the confinement are shown. Neoclassical effects as well as the nonclassical processes are discussed. Emphasis is made on the connection with the improved confinement. Convective cell, i.e. the nonuniform potential on the magnetic surface is also discussed. The roles of the fluctuating electric field are then reviewed. The progress in the recent theories on the anomalous transport is addressed. Through these surveys, the impact of the experiments using the heavy ion beam probes on the modern plasma physics is illustrated. (author) 66 refs

  12. Toroidal and poloidal momentum transport studies in JET

    Science.gov (United States)

    Tala, T.; Andrew, Y.; Crombé, K.; de Vries, P. C.; Garbet, X.; Hawkes, N.; Nordman, H.; Rantamäki, K.; Strand, P.; Thyagaraja, A.; Weiland, J.; Asp, E.; Baranov, Y.; Challis, C.; Corrigan, G.; Eriksson, A.; Giroud, C.; Hua, M.-D.; Jenkins, I.; Knoops, H. C. M.; Litaudon, X.; Mantica, P.; Naulin, V.; Parail, V.; Zastrow, K.-D.; contributors, JET-EFDA

    2007-08-01

    This paper reports on the recent studies of toroidal and poloidal momentum transport in JET. The ratio of the global energy confinement time to the momentum confinement is found to be close to τE/τphi = 1 except for the low density or low collisionality discharges where the ratio is τE/τphi = 2-3. On the other hand, local transport analysis of around 40 discharges shows that the ratio of the local effective momentum diffusivity to the ion heat diffusivity is χphi/χi ap 0.1-0.4 (averaged over the radial region r/a = 0.4-0.7) rather than unity, as expected from the global confinement times and used often in ITER predictions. The apparent discrepancy in the global and local momentum versus ion heat transport can be at least partly explained by the fact that momentum confinement within edge pedestal is worse than that of the ion heat and thus, momentum pedestal is weaker than that of ion temperature. In addition, while the ion temperature profile shows clearly strong profile stiffness, the toroidal velocity profile does not exhibit stiffness, as exemplified here during a giant ELM crash. Predictive transport simulations with the self-consistent modelling of toroidal velocity using the Weiland model and GLF23 also confirm that the ratio χphi/χi ap 0.4 reproduces the core toroidal velocity profiles well and similar accuracy with the ion temperature profiles. Concerning poloidal velocities on JET, the experimental measurements show that the carbon poloidal velocity can be an order of magnitude above the neo-classical estimate within the ITB. This significantly affects the calculated radial electric field and therefore, the E × B flow shear used for example in transport simulations. Both the Weiland model and GLF23 reproduce the onset, location and strength of the ITB well when the experimental poloidal velocity is used while they do not predict the formation of the ITB using the neo-classical poloidal velocity in time-dependent transport simulation. The most

  13. Toroidal deuteron accelerator for Mo-98 neutron activation

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Wagner L., E-mail: wagner.leite@ifnmg.edu.br, E-mail: tprcampos@pq.cnpq.br [Instituto Federal do Norte de Minas Gerais (IFN-MG), Montes Claros, MG (Brazil); Campos, Tarcisio P.R. Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear

    2017-07-01

    The radionuclide Tc-{sup 99m} is the most useful radioisotope in nuclear medicine. It can be produced by the Mo-99 beta minus decay. Mo-99 has often been produced in a high- flux nuclear reactor through radioactive neutron capture reactions on Mo-98. The present paper provides a preliminary design of a toroidal transmutation system (TTS) based on a toroidal compact deuteron accelerator, which can provide the Mo-98 transmutation into Mo-99. This system is essentially composed of a multi-aperture plasma electrode and a target, submitted to 180 kV, where a positive deuteron beam is accelerated toward a titanium-target loaded with deuterium in which nuclear d-d fusion reactions are induced. The Particle Studio package of the Computer Simulation Technology (CST) software was applied to design, simulate and optimize the deuteron beam on the target. MCNP code provided to neutronic analysis. Based on electromagnetic and neutronic simulations, the neutron yield and reaction rates were estimated. The simulated data allowed appraising the Mo-99 activity. A TTS, in a specific configuration, could produce a total deuterium current of 1.6 A at the target and a neutron yield of 10{sup 13} n.s{sup -1}. In a arrangement of 30 column samples, TTS provides 230 mCi s{sup -1} Mo{sup 99} in each column, which represents 80% of Tc-99m in secular equilibrium. As conclusion, the system holds potential for generating Mo-99 and Tc-99m in a suitable activity in secular equilibrium. (author)

  14. Parametric design studies of toroidal magnetic energy storage units

    International Nuclear Information System (INIS)

    Herring, J.S.

    1990-01-01

    Superconducting magnetic energy storage (SMES) units have a number of advantages as storage devices. Electrical current is the input, output and stored medium, allowing for completely solid-state energy conversion. The magnets themselves have no moving parts. The round-trip efficiency is higher than those for batteries, compressed air or pumped hydro. Output power can be very high, allowing complete discharge of the unit within a few seconds. Finally, the unit can be designed for a very large number of cycles, limited basically by fatigue in the structural components. A small systems code has been written to produce and evaluate self-consistent designs for toroidal superconducting energy storage units. The units can use either low temperature or high temperature superconductors. The coils have 'D' shape where the conductor and its stabilizer/structure is loaded only in tension and the centering forces are borne by a bucking cylinder. The coils are convectively cooled from a cryogenic reservoir in the bore of the coils. The coils are suspended in a cylindrical metal shell which protects the magnet during rail, automotive or shipboard use. It is important to note that the storage unit does not rely on its surroundings for structural support, other than normal gravity and inertial loads. This paper presents designs for toroidal energy storage units produced by the systems code. A wide range of several parameters have been considered, resulting in units storing from 1 MJ to 72 GJ. Maximum fields range from 5 t to 20 T. The masses and volumes of the coils, bucking cylinder, coolant, insulation and outer shell are calculated. For unattended use, the allowable operating time using only the boiloff of the cryogenic fluid for refrigeration is calculated. For larger units, the coils have been divided into modules suitable for normal truck or rail transport. 8 refs., 5 tabs

  15. Spontaneous Atraumatic Mediastinal Hemorrhage

    Directory of Open Access Journals (Sweden)

    Morkos Iskander BSc, BMBS, MRCS, PGCertMedEd

    2013-04-01

    Full Text Available Spontaneous atraumatic mediastinal hematomas are rare. We present a case of a previously fit and well middle-aged lady who presented with acute breathlessness and an increasing neck swelling and spontaneous neck bruising. On plain chest radiograph, widening of the mediastinum was noted. The bruising was later confirmed to be secondary to mediastinal hematoma. This life-threatening diagnostic conundrum was managed conservatively with a multidisciplinary team approach involving upper gastrointestinal and thoracic surgeons, gastroenterologists, radiologists, intensivists, and hematologists along with a variety of diagnostic modalities. A review of literature is also presented to help surgeons manage such challenging and complicated cases.

  16. Moment of truth for CMS

    CERN Multimedia

    2006-01-01

    One of the first events reconstructed in the Muon Drift Tubes, the Hadron Calorimeter and elements of the Silicon Tracker (TK) at 3 Tesla. The atmosphere in the CMS control rooms was electric. Everbody was at the helm for the first full-scale testing of the experiment. This was a crunch moment for the entire collaboration. On Tuesday, 22 August the magnet attained almost its nominal power of 4 Tesla! At the same moment, in a tiny improvised control room, the physicists were keyed up to test the entire detector system for the first time. The first cosmic ray tracks appeared on their screens in the week of 15 August. The tests are set to continue for several weeks more until the first CMS components are lowered into their final positions in the cavern.

  17. New type of wavelet-based spectral analysis by which modes with different toroidal mode number are separated

    Science.gov (United States)

    Ohdachi, S.

    2016-11-01

    A new type of wavelet-based analysis for the magnetic fluctuations by which toroidal mode number can be resolved is proposed. By using a wavelet, having a different phase toroidally, a spectrogram with a specific toroidal mode number can be obtained. When this analysis is applied to the measurement of the fluctuations observed in the large helical device, MHD activities having similar frequency in the laboratory frame can be separated from the difference of the toroidal mode number. It is useful for the non-stationary MHD activity. This method is usable when the toroidal magnetic probes are not symmetrically distributed.

  18. Program for development of toroidal superconducting magnets for fusion research, May 1975

    International Nuclear Information System (INIS)

    Long, H.M.; Lubell, M.S.

    1975-11-01

    The objective of this program is a tested magnet design which demonstrates the suitability and reliability needed to qualify toroidal superconducting magnets for fusion research devices in a time compatible with the D-T burning experiments time frame. The overall applied development program including tasks, manpower, and cost estimates is detailed here, but for the full toroidal system only the cost and time frame are outlined to show compatibility with the present program. The details of the full toroidal system fall under major device fabrication and will be included in a subsequent document

  19. Theoretical studies of possible toroidal high-spin isomers in the light-mass region

    Directory of Open Access Journals (Sweden)

    Staszczak Andrzej

    2016-01-01

    Full Text Available We review our theoretical knowledge of possible toroidal high-spin isomers in the light mass region in 28≤A≤52 obtained previously in cranked Skyrme-Hartree-Fock calculations. We report additional toroidal high-spin isomers in 56Ni with I=114ħ and 140ħ, which follow the same (multi-particle–(multi-hole systematics as other toroidal high-spin isomers. We examine the production of these exotic nuclei by fusion of various projectiles on 20Ne or 28Si as an active target in time-projection-chamber (TPC experiments.

  20. Identification of Optical Component of North Toroidal Source of Sporadic Meteors and its Origin

    Science.gov (United States)

    Hashimoto, T.; Watanabe, J.; Sato, M.; Ishiguro, M.

    2011-01-01

    We succeeded to identify the North Toroidal source by optical observations performed by the SonotaCo Network, which is a TV observation network coordinated by Japanese amateurs. This source has been known only for radar observations until now. The orbits of the optical meteors in the North Toroidal source are relatively large eccentricity and semi-major axis, compared with those of the radar meteors. In this paper, we report the characteristics of this North Toroidal source detected by optical observations, and discuss the possible origin and evolution of this source.

  1. Spontaneous Appendicocutaneous Fistula I

    African Journals Online (AJOL)

    M T0k0de* MB, BS and. Dr 0. A. AWOj0bi+ FMCS (Nig). ABSTRACT. Ruptured appendicitis is not a common cause of spontaneous enterocutaneous fistula. A case of ruptured retrocaecal appendicitis presenting as an enterocutaneous fistula in a Nigerian woman is presented. The literature on this disorder is also reviewed.

  2. [Spontaneous bacterial peritonitis].

    Science.gov (United States)

    Strauss, Edna; Caly, Wanda Regina

    2003-01-01

    Spontaneous bacterial peritonitis occurs in 30% of patients with ascites due to cirrhosis leading to high morbidity and mortality rates. The pathogenesis of spontaneous bacterial peritonitis is related to altered host defenses observed in end-stage liver disease, overgrowth of microorganisms, and bacterial translocation from the intestinal lumen to mesenteric lymph nodes. Clinical manifestations vary from severe to slight or absent, demanding analysis of the ascitic fluid. The diagnosis is confirmed by a number of neutrophils over 250/mm3 associated or not to bacterial growth in culture of an ascites sample. Enterobacteriae prevail and Escherichia coli has been the most frequent bacterium reported. Mortality rates decreased markedly in the last two decades due to early diagnosis and prompt antibiotic treatment. Third generation intravenous cephalosporins are effective in 70% to 95% of the cases. Recurrence of spontaneous bacterial peritonitis is common and can be prevented by the continuous use of oral norfloxacin. The development of bacterial resistance demands the search for new options in the prophylaxis of spontaneous bacterial peritonitis; probiotics are a promising new approach, but deserve further evaluation. Short-term antibiotic prophylaxis is recommended for patients with cirrhosis and ascites shortly after an acute episode of gastrointestinal bleeding.

  3. Spontaneous Grammar Explanations.

    Science.gov (United States)

    Tjoo, Hong Sing; Lewis, Marilyn

    1998-01-01

    Describes one New Zealand university language teacher's reflection on her own grammar explanations to university-level students of Bahasa Indonesian. Examines form-focused instruction through the teacher's spontaneous answers to students' questions about the form of the language they are studying. The teacher's experiences show that it takes time…

  4. EDITORIAL SPONTANEOUS BACTERIAL PERITONITIS ...

    African Journals Online (AJOL)

    hi-tech

    Spontaneous bacterial peritonitis (SBP) frequent]y occurs in patients with liver cirrhosis and ascites. It is defined as an infection of previously sterile ascitic fluid without any demonstrable intrabdominal source of infection. It is now internationally agreed that a polymorphonuclear (PMN) cell count in the ascitic fluid of over 250 ...

  5. Spontaneous dimensional reduction?

    Science.gov (United States)

    Carlip, Steven

    2012-10-01

    Over the past few years, evidence has begun to accumulate suggesting that spacetime may undergo a "spontaneous dimensional reduction" to two dimensions near the Planck scale. I review some of this evidence, and discuss the (still very speculative) proposal that the underlying mechanism may be related to short-distance focusing of light rays by quantum fluctuations.

  6. Moment Closure for the Stochastic Logistic Model

    National Research Council Canada - National Science Library

    Singh, Abhyudai; Hespanha, Joao P

    2006-01-01

    ..., which we refer to as the moment closure function. In this paper, a systematic procedure for constructing moment closure functions of arbitrary order is presented for the stochastic logistic model...

  7. Wild bootstrap versus moment-oriented bootstrap

    OpenAIRE

    Sommerfeld, Volker

    1997-01-01

    We investigate the relative merits of a “moment-oriented” bootstrap method of Bunke (1997) in comparison with the classical wild bootstrap of Wu (1986) in nonparametric heteroscedastic regression situations. The “moment-oriented” bootstrap is a wild bootstrap based on local estimators of higher order error moments that are smoothed by kernel smoothers. In this paper we perform an asymptotic comparison of these two dierent bootstrap procedures. We show that the moment-oriented bootstrap is in ...

  8. On the interpretation of the support moment

    NARCIS (Netherlands)

    Hof, AL

    2000-01-01

    It has been suggested by Winter (J. Biomech. 13 (1980) 923-927) that the 'support moment', the sum of the sagittal extension moments, shows less variability in walking than any of the joint moments separately. A simple model is put forward to explain this finding. It is proposed to reformulate the

  9. some deficiencies in using moment generating functions

    African Journals Online (AJOL)

    Two deficiencies in using moment-generating functions are given and illustrated with examples. Many distributions do not have moment generating functions, but every distribution has a unique characteristic function. The use of characteristic functions is preferred to moment-generating functions. KEY WORDS: ...

  10. Electromagnetic moments of 22F

    Science.gov (United States)

    Mihara, M.; Matsuta, K.; Komurasaki, J.; Hirano, H.; Nishimura, D.; Momota, S.; Ohtsubo, T.; Izumikawa, T.; Shimbara, Y.; Kubo, T.; Kameda, D.; Zhou, Dongmei; Zheng, Yongnan; Yuan, Daqing; Zhu, Shengyun; Kitagawa, A.; Kanazawa, M.; Torikoshi, M.; Sato, S.; Nagatomo, T.; Matsumiya, R.; Ishikawa, D.; Fukuda, M.; Minamisono, T.; Nojiri, Y.; Alonso, J. R.; Crebs, G. F.; Symons, T. J. M.

    2010-03-01

    The magnetic dipole (μ) and electric quadrupole (Q) moments of short-lived nucleus 22F (Iπ=4+, T=4.2s) have been measured for the first time by means of the β-NMR technique. A spin polarized 22F beam was produced through the charge exchange reaction of 22Ne and was implanted into single crysltals of NaF and MgF2 for μ and Q measurements, respectively. As a result, |μ(F22)|=(2.69443±0.00039)μ and |Q(F22)|=(3±2)mb was obtained. These values are well reproduced by the shell model calculations.

  11. Electric and Magnetic Dipole Moments

    CERN Multimedia

    CERN. Geneva

    2005-01-01

    The stringent limit on the electric dipole moment of the neutron forced the issue on the strong CP-problem. The most elegant solution of which is the axion field proposed by Peccei and Quinn. The current limit on the QCD parameter theta coming from the limit on the neutron EDM is of order 10-10. I am going to describe the present status on the neutron EDM searches and further prospects on getting down to theta_qcd sensitivity of 10-13 with the new deuteron EDM in storage rings proposal. For completeness the current status and prospects of the muon g-2 experiment will also be given.

  12. Toroidal electric field in front of the lower hybrid grill of the castor tokamak

    International Nuclear Information System (INIS)

    Zacek, F.; Petrzilka, V.; Devynck, P.; Goniche, M.

    2003-01-01

    A small tokamak Castor (R/a = 0.4/0.85 m) with low plasma energy density and short pulses (20 ms) offers a unique possibility to carry out probe measurements in front of the grill antenna and as a consequence to provide direct information about the local electric fields in this region. For measurements of the toroidal electrical field, a small double probe with 2 tips separated by 3.5 mm in the toroidal direction has been used. The tips are oriented in the radial direction. The probe is radially movable in front of the central grill waveguide. Cross-correlations and FFT (fast Fourier transform) analysis of the measured V fl signals are given together with an attempt to investigate characteristics of toroidal electric field E tor (up to 500 kHz), derived from V fl measured by 2 toroidally separated tips

  13. On the Ideal Boundary Condition in a General Toroidal Geometry for a Mixed Magnetic Field Representation

    International Nuclear Information System (INIS)

    Tang, X. Z.

    2000-01-01

    Subtleties of implementing the standard perfectly conducting wall boundary condition in a general toroidal geometry are clarified for a mixed scalar magnetic field representation. An iterative scheme based on Ohm's law is given

  14. Current generation by unidirectional lower hybrid waves in the ACT-1 toroidal device

    International Nuclear Information System (INIS)

    Wong, K.L.; Horton, R.; Ono, M.

    1980-05-01

    An unambiguious experimental observation of current generation by unidirectional lower hybrid waves in a toroidal plasma is reported. Up to 10 amperes of current was driven by 500 watts of rf power at 160 MHz

  15. Calculation of modification to the toroidal magnetic field of the Tokamak Novillo. Part II

    International Nuclear Information System (INIS)

    Melendez L, L.; Chavez A, E.; Colunga S, S.; Valencia A, R.; Lopez C, R.; Gaytan G, E.

    1992-03-01

    In a cylindrical magnetic topology. the confined plasma experiences 'classic' collisional transport phenomena. When bending the cylinder with the purpose of forming a toro, the magnetic field that before was uniform now it has a radial gradient which produces an unbalance in the magnetic pressure that is exercised on the plasma in the transverse section of the toro. This gives place to transport phenomena call 'neo-classicist'. In this work the structure of the toroidal magnetic field produced by toroidal coils of triangular form, to which are added even of coils of compensation with form of half moon is analyzed. With this type of coils it is looked for to minimize the radial gradient of the toroidal magnetic field. The values and characteristics of B (magnetic field) in perpendicular planes to the toro in different angular positions in the toroidal direction, looking for to cover all the cases of importance are exhibited. (Author)

  16. Engineering status of the superconducting end cap toroid magnets for the ATLAS experiment at LHC

    CERN Document Server

    Baynham, D Elwyn; Carr, F S; Courthold, M J D; Cragg, D A; Densham, C J; Evans, D; Holtom, E; Rochford, J; Sole, D; Towndrow, Edwin F; Warner, G P

    2000-01-01

    The ATLAS experiment at LHC, CERN will utilise a large, superconducting, air-cored toroid magnet system for precision muon measurements. The magnet system will consist of a long barrel and two end-cap toroids. Each end-cap toroid will contain eight racetrack coils mounted as a single cold mass in cryostat vessel of ~10 m diameter. The project has now moved from the design/specification stage into the fabrication phase. This paper presents the engineering status of the cold masses and vacuum vessels that are under fabrication in industry. Final designs of cold mass supports, cryogenic systems and control/protection systems are presented. Planning for toroid integration, test and installation is described. (3 refs).

  17. How to calculate the neoclassical viscosity, diffusion, and current coefficients in general toroidal plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Sugama, H.; Nishimura, S.

    2002-05-01

    A novel method to obtain the full neoclassical transport matrix for general toroidal plasmas by using the solution of the linearized drift kinetic equation with the pitch-angle-scattering collision operator is shown. In this method, the neoclassical coefficients for both poloidal and toroidal viscosities in toroidal helical systems can be obtained, and the neoclassical transport coefficients for the radial particle and heat fluxes and the bootstrap current with the non-diagonal coupling between unlike-species particles are derived from combining the viscosity-flow relations, the friction-flow relations, and the parallel momentum balance equations. Since the collisional momentum conservation is properly retained, the well-known intrinsic ambipolar condition of the neoclassical particle fluxes in symmetric systems is recovered. Thus, these resultant neoclassical diffusion and viscosity coefficients are applicable to evaluating accurately how the neoclassical transport in quasi-symmetric toroidal systems deviates from that in exactly-symmetric systems. (author)

  18. Spontaneous healing of spontaneous coronary artery dissection.

    Science.gov (United States)

    Almafragi, Amar; Convens, Carl; Heuvel, Paul Van Den

    2010-01-01

    Spontaneous coronary artery dissection (SCAD) is a rare cause of acute coronary syndrome and sudden cardiac death. It should be suspected in every healthy young woman without cardiac risk factors, especially during the peripartum or postpartum periods. It is important to check for a history of drug abuse, collagen vascular disease or blunt trauma of the chest. Coronary angiography is essential for diagnosis and early management. We wonder whether thrombolysis might aggravate coronary dissection. All types of treatment (medical therapy, percutaneous intervention or surgery) improve the prognosis without affecting survival times if used appropriately according to the clinical stability and the angiographic features of the involved coronary arteries. Prompt recognition and targeted treatment improve outcomes. We report a case of SCAD in a young female free of traditional cardiovascular risk factors, who presented six hours after thrombolysis for ST elevation myocardial infarction. Coronary angiography showed a dissection of the left anterior descending and immediate branch. She had successful coronary artery bypass grafting, with complete healing of left anterior descending dissection.

  19. Safety analysis of superconducting toroidal field magnet for tokamak experimental fusion reactor

    International Nuclear Information System (INIS)

    1979-02-01

    Safety analysis of the superconducting toroidal field magnet for a Tokamak experimental fusion reactor has been carried out. Works were accident classification, FMEA and FTA analyses, coil stability and quench behavior calculations, failure detection and coil protection system designs, structure analysis, fracture and fatigue studies, and earthquake response analysis. Accident analysis of cryostat and refrigeration system was also performed. The objective of this work is to reveal technological problems of the toroidal field magnet by safety analysis. (author)

  20. Calculation about a modification to the toroidal magnetic field of the Tokamak Novillo. Part I; Calculo sobre una modificacion al campo magnetico toroidal del Tokamak Novillo. Parte I

    Energy Technology Data Exchange (ETDEWEB)

    Chavez A, E.; Melendez L, L.; Colunga S, S.; Valencia A, R.; Lopez C, R.; Gaytan G, E

    1991-07-15

    The charged particles that constitute the plasma in the tokamaks are located in magnetic fields that determine its behavior. The poloidal magnetic field of the plasma current and the toroidal magnetic field of the tokamak possess relatively big gradients, which produce drifts on these particles. These drifts are largely the cause of the continuous lost of particles and of energy of the confinement region. In this work the results of numerical calculations of a modification to the 'traditional' toroidal magnetic field that one waits it diminishes the drifts by gradient and improve the confinement properties of the tokamaks. (Author)

  1. Reconstruction of convex bodies from moments

    DEFF Research Database (Denmark)

    Hörrmann, Julia; Kousholt, Astrid

    We investigate how much information about a convex body can be retrieved from a finite number of its geometric moments. We give a sufficient condition for a convex body to be uniquely determined by a finite number of its geometric moments, and we show that among all convex bodies, those which......- rithm that approximates a convex body using a finite number of its Legendre moments. The consistency of the algorithm is established using the stabil- ity result for Legendre moments. When only noisy measurements of Legendre moments are available, the consistency of the algorithm is established under...

  2. Field Induced Magnetic Moments in a Metastable Iron-Mercury Alloy

    DEFF Research Database (Denmark)

    Pedersen, M.S.; Mørup, Steen; Linderoth, Søren

    1996-01-01

    The magnetic properties of a metastable iron-mercury alloy have been investigated in the temperature range from 5 to 200 K by Mossbauer spectroscopy and magnetization measurements. At low temperature the magnetic moment per iron atom is larger than af alpha-Fe. The effective spontaneous magnetic ....... It was found that the field-induced increase of the magnetic moment in the metastable iron-mecury alloy was about 0.06 Bohr magnetons per iron atom in the temperature range from 5 to 200 K for a field change from 6 to 12 T....

  3. Predicting Robust Learning with the Visual Form of the Moment-by-Moment Learning Curve

    Science.gov (United States)

    Baker, Ryan S.; Hershkovitz, Arnon; Rossi, Lisa M.; Goldstein, Adam B.; Gowda, Sujith M.

    2013-01-01

    We present a new method for analyzing a student's learning over time for a specific skill: analysis of the graph of the student's moment-by-moment learning over time. Moment-by-moment learning is calculated using a data-mined model that assesses the probability that a student learned a skill or concept at a specific time during learning (Baker,…

  4. Spontaneous spinal epidural abscess.

    LENUS (Irish Health Repository)

    Ellanti, P

    2011-10-01

    Spinal epidural abscess is an uncommon entity, the frequency of which is increasing. They occur spontaneously or as a complication of intervention. The classical triad of fever, back pain and neurological symptoms are not always present. High index of suspicion is key to diagnosis. Any delay in diagnosis and treatment can have significant neurological consequences. We present the case of a previously well man with a one month history of back pain resulting from an epidural abscess.

  5. First End Cap Toroid knocking on the door of SX1

    CERN Multimedia

    Herman Ten Kate

    On Tuesday May 29, the first Toroid End Cap for the A-side was transported from its test station next to B180 to the front of the ATLAS surface building SX1. The 240-ton and 12-m high toroid end-cap moved on a special trailer at walking speed, got over various slopes and survived the difficult turn left in front of the entrance at gate B. The toroid had to wait for almost two months to commence its journey to its destination as the cryogenic test down to 80K was already successfully completed by early April. In the next days, the toroid will slide into the SX1 building, turn around its axes by 90 degrees and then gently slide over the first shaft and land on top of the A-side shaft on Wednesday. There, it will descend by 5 m into the shaft using special lifting tooling before it can be connected to the 2x140 tons overhead cranes which will let the toroid go further down to the cavern. End Cap Toroid A on the trailer on its way to the cavern at Point 1. Crossing the main road near entrance A while t...

  6. Dielectric tensor operator of hot plasmas in toroidal axisymmetric systems

    International Nuclear Information System (INIS)

    Brunner, S.; Vaclavik, J.

    1992-08-01

    Kinetic theory is used to develop equations describing dynamics of small-amplitude electromagnetic perturbations in toroidal axisymmetric plasmas. The closed Vlasov-Maxwell equations are first solved for a hot stationary plasma using the expansion in the small parameter ε e =ρ/L, where ρ is the Larmor radius and L a characteristic length scale of the stationary state. The ordering and additional assumptions are specified so as to obtain the well-known Grad-Shafranov equation. The dielectric tensor of such a plasma is then derived. The Vlasov equation for the perturbed distribution function is solved by the expansion in the small parameters ε e and ε p =ρ/λ, where λ is a characteristic wavelength of the perturbing electromagnetic field. The solution is obtained up to the first order in ε e and the second order in ε p . By integrating the resulting distribution function over velocity space, an explicit expression for the tensor is derived in the form of a two-dimensional partial differential operator. The operator is shown to possess the proper symmetry corresponding to the energy conservation law. (author) 6 refs

  7. Design study of toroidal magnets for tokamak experimental power reactors

    International Nuclear Information System (INIS)

    Stekly, Z.J.J.; Lucas, E.J.

    1976-12-01

    This report contains the results of a six-month study of superconducting toroidal field coils for a Tokamak Experimental Power Reactor to be built in the late 1980s. The designs are for 8 T and 12 T maximum magnetic field at the superconducting winding. At each field level two main concepts were generated; one in which each of the 16 coils comprising the system has an individual vacuum vessel and the other in which all the coils are contained in a single vacuum vessel. The coils have a D shape and have openings of 11.25 m x 7.5 m for the 8 T coils and 10.2 m x 6.8 m for the 12 T coils. All the designs utilize rectangular cabled conductor made from copper stabilized Niobium Titanium composite which operates at 4.2 K for the 8 T design and at 2.5 K for the 12 T design. Manufacturing procedures, processes and schedule estimates are also discussed

  8. Rotating liquid blanket for a toroidal fusion reator

    International Nuclear Information System (INIS)

    Moir, R.W.

    1987-01-01

    A novel blanket concept is presented for toroidal geometry in which many of the limitations imposed by a first wall are avoided by not having a first wall in the usual sense. The blanket consists of a rapidly rotating, low-vapor-pressure liquid that has a sharp boundary with the vacuum region. Nozzles inject ja continuous layer of cool liquid on the inner surface. The noncentricity of the plasma is maintained so that the plasma scrape-off region intersects the rotating liqid in a localized region. This noncentricity allows sufficient space so that the scrape-off plasma layer will not bombard the nozzles, whch penetrate through the rotating liquid. This liquid ''first wall'' is bombarded by the plasma, resulting in heat deposition, sputtering, and evaporation during the short time before the exposed liquid is covered by fresh, cool liquid from the nozzles. The advantages of this reactor concept appear to be very high wall loadings (speculated to be over 10 MW/m 2 ) and long component lifetime, both crucial economic factors. The nozzles are designed for easy replacement. The reactor's disatvantage is its enormous potential for plasma contamination by impurities. (orig.)

  9. Linear theory of the tearing instability in axisymmetric toroidal devices

    International Nuclear Information System (INIS)

    Rogister, A.; Singh, R.

    1988-08-01

    We derive a very general kinetic equation describing the linear evolution of low m/l modes in axisymmetric toroidal plasmas with arbitrary cross sections. Included are: Ion sound, inertia, diamagnetic drifts, finite poloidal beta, and finite ion Larmor radius effects. Assuming the magnetic surfaces to form a set of nested tori with circular cross sections of shifted centers, and introducing adequate simplifications justified by our knowledge of experimental tokamak plasmas, we then obtain explicitely the sets of equations describing the coupling of the quasimodes 0/1, 1/1, 2/1, and, for m≥2, m/1, (m+1)/1. By keeping finite aspect ratio effects into account when calculating the jump of the derivative of the eigenfunction, it is shown that the theory can explain the rapid evolution, within one sawtooth period, of the growth rate of the sawteeth precursors from resistive values to magnetohydrodynamic ones. The characteristics thus theoretically required from current profiles in sawtoothing discharges have clearly been observed. Other aspects of the full theory could be relevant to the phenomenon of major disruptions. (orig.)

  10. Structural analysis of the NET toroidal field coils and conductor

    International Nuclear Information System (INIS)

    Mitchell, N.; Collier, D.; Gori, R.

    1989-01-01

    The NET toroidal field coils will utilise A15-type superconductor at 4.2 K to generate fields up to 11.5 T. The superconductor strands themselves are sensitive to strain, which causes degradation of their current carrying capacity, and thus the detailed behaviour of the coil conductor must be analysied so that the strian can be minimised. This analysis must include the manufacturing processes of the conductor as well as the normal and abnormal loperational loads. The conductor will be insulated and bonded by glass fibre reinforced epoxy resin, with limited bonding shear strength, and the overall support of the complete coil system must be designed to reduce these shear stresses. The coils will be subjected to pulse loads form the poloidal field coils, and analysis of the slip between the various coil components, such as conductors and the coil case, giving rise to frictional heating and possible loss of superconducting properties is another important factor, which has been investigated by a number of stress analyses. The manufacturing, thermal and normal magnetic loads on the coils and the analysis leading to the proposed structural design are described. In addition to the normal operating conditions, there is a range of abnormal load conditions which could result from electrical or mechanical faults on the coils. The effect of these potential faults has been analysed and the coil design modified to prevent catastrophic structural failure. (author). 13 refs.; 8 figs.; 1 tab

  11. Wall conditioning and leak localization in the Advanced Toroidal Facility

    International Nuclear Information System (INIS)

    Langley, R.A.; Glowienka, J.C.; Mioduszewski, P.K.; Murakami, M.; Rayburn, T.F.; Simpkins, J.E.; Schwenterly, S.W.; Yarber, J.L.

    1990-01-01

    The Advanced Toroidal Facility (ATF) vacuum vessel and its internal components have been conditioned for plasma operation by baking, discharge cleaning with hydrogen and helium, and gettering with chromium and titanium. The plasma-facing surface of ATF consists mainly of stainless steel with some graphite; the outgassing area is dominated by the graphite because of its open porosity. Since this situation is somewhat different from that in other fusion plasma experiments, in which a single material dominates both the outgassing area and the plasma-facing area, different cleaning and conditioning techniques are required. The situation was aggravated by air leaks in the vacuum vessel, presumably resulting from baking and from vibration during plasma operation. The results of the various cleaning and conditioning techniques used are presented and compared on the basis of residual gas analysis and plasma performance. A technique for detecting leaks from the inside of the vacuum vessel is described. This technique was developed because access to the outside of the vessel is severely restricted by external components

  12. Progress on Thomson scattering in the Pegasus Toroidal Experiment

    Science.gov (United States)

    Schlossberg, D. J.; Bongard, M. W.; Fonck, R. J.; Schoenbeck, N. L.; Winz, G. R.

    2013-11-01

    A novel Thomson scattering system has been implemented on the Pegasus Toroidal Experiment where typical densities of 1019 m-3 and electron temperatures of 10 to 500 eV are expected. The system leverages technological advances in high-energy pulsed lasers, volume phase holographic (VPH) diffraction gratings, and gated image intensified (ICCD) cameras to provide a relatively low-maintenance, economical, robust diagnostic system. Scattering is induced by a frequency-doubled, Q-switched Nd:YAG laser (2 J at 532 nm, 7 ns FWHM pulse) directed to the plasma over a 7.7 m long beam path, and focused to VPH transmission gratings (eff. > 80%) and fast-gated ICCDs (gate > 2 ns, Gen III intensifier) with high-throughput (F/1.8), achromatic lensing. A stray light mitigation facility has been implemented, consisting of a multi-aperture optical baffle system and a simple beam dump. Successful stray light reduction has enabled detection of scattered signal, and Rayleigh scattering has been used to provide a relative calibration. Initial temperature measurements have been made and data analysis algorithms are under development.

  13. First assembly phase for the ATLAS toroid coils

    CERN Multimedia

    Patrice Loïez

    2003-01-01

    The ATLAS barrel toroid system consists of eight coils, each of axial length 25.3 m, assembled radially and symmetrically around the beam axis. The coils are of a flat racetrack type with two double-pancake windings made of 20.5 kA aluminium-stabilized niobium-titanium superconductor. In the first phase of assembly, the two 'pancakes' are packed into their vacuum vessel. This is done using bladders filled with resin and glass microbeads under pressure. The resin is heated and, once cooled, holds the pancakes in place. The operation has to be performed on both sides of the coil, which necessitated a special technique to turn the coils over and then transport them to the heating table. Photos 01, 02, 03: Use of the overhead travelling crane to hoist the coil up and then tilt it over, the coil frame's metal feet being used as rotational pivots, supporting half the coil's weight. Once it has been turned over, the coil, now with only half the frame, is transported to the heating table using a special lifting gant...

  14. Ballooning modes or Fourier modes in a toroidal plasma?

    International Nuclear Information System (INIS)

    Connor, J.W.; Taylor, J.B.

    1987-01-01

    The relationship between two different descriptions of eigenmodes in a torus is investigated. In one the eigenmodes are similar to Fourier modes in a cylinder and are highly localized near a particular rational surface. In the other they are the so-called ballooning modes that extend over many rational surfaces. Using a model that represents both drift waves and resistive interchanges the transition from one of these structures to the other is investigated. In this simplified model the transition depends on a single parameter which embodies the competition between toroidal coupling of Fourier modes (which enhances ballooning) and variation in frequency of Fourier modes from one rational surface to another (which diminishes ballooning). As the coupling is increased each Fourier mode acquires a sideband on an adjacent rational surface and these sidebands then expand across the radius to form the extended mode described by the conventional ballooning mode approximation. This analysis shows that the ballooning approximation is appropriate for drift waves in a tokamak but not for resistive interchanges in a pinch. In the latter the conventional ballooning effect is negligible but they may nevertheless show a ballooning feature. This is localized near the same rational surface as the primary Fourier mode and so does not lead to a radially extended structure

  15. MHD simulation study of compact toroid injection into magnetized plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Yoshio; Kishimoto, Yasuaki [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Hayashi, Takaya [National Inst. for Fusion Science, Toki, Gifu (Japan)

    2000-06-01

    To understand the fuelling process in a fusion device by a compact toroid (CT) plasmoid injection method, we have carried out MHD numerical simulations where a spheromak-like CT (SCT) is injected into a magnetized target plasma region. So far, we revealed that the penetration depth of the SCT plasma becomes shorter than that estimated from the conducting sphere (CS) model, because in the simulation the Lorentz force of the target magnetic field sequentially decelerates the injected SCT while in the CS model only the magnetic pressure force acts as the deceleration mechanism. In this study, we represent the new theoretical model where the injected SCT is decelerated by both the magnetic pressure force and the magnetic tension force (we call it the non-slipping sphere (NS) model) and investigate in detail the deceleration mechanism of the SCT by comparison with simulation results. As a result, it is found that the decrease of the SCT kinetic energy in the simulation coincides with that in the NS model more than in the CS model. It means that not only the magnetic pressure force but also the magnetic tension force acts as the deceleration mechanism of the SCT. Furthermore, it is revealed that magnetic reconnection between the SCT magnetic field and the target magnetic field plays a role to relax the SCT deceleration. (author)

  16. Toroidal coil for torus type nuclear fusion device

    International Nuclear Information System (INIS)

    Nagata, Daisaburo; Jinbo, Kensaku.

    1976-01-01

    Object: To facilitate clamping operation in the joint section of a toroidal coil in the nuclear fusion device even if the device has a narrow central space. Structure: A clamp bolt for joining upper and lower coil conductors comprises a first bolt, which is provided in one end portion with a thread for fitting a clamp nut, has a hollow intermediate portion and is provided at the other end with an opening of a smaller diameter than that of the hollow intermediate portion and also with an inner receiving surface, and a second bolt, which is provided in one end portion with a thread for fitting a clamp nut and in the other end portion with a raised portion and is adapted to be inserted on the raised portion side into the hollow intermediate portion of the first bolt such that it is extendable in the axial direction. When inserting this clamp bolt into a see-through hole in the conductor joint section its length is reduced, and at the time of clamping it is extended with the raised portion of the second bolt locked by the receiving surface of the first bolt. (Horiuchi, T.)

  17. Control of Compact-Toroid Characteristics by External Copper Shell

    Science.gov (United States)

    Matsumoto, T.; Sekiguchi, J.; Asai, T.; Gota, H.; Roche, T.; Allfrey, I.; Cordero, M.; Garate, E.; Kinley, J.; Valentine, T.; Waggoner, W.; the TAE Team

    2015-11-01

    A collaborative research project by Tri Alpha Energy and Nihon University has been conducted for several years, which led to the development of a new compact toroid (CT) injector for efficient FRC particle refueling in the C-2U experiment. The CT is formed by a magnetized coaxial plasma gun (MCPG), consisting of coaxial cylindrical electrodes. In CT formation via MCPG, the magnetic helicity content of the generated CT is one of the critical parameters. A bias coil is inserted into the inner electrode to generate a poloidal flux. The resultant bias magnetic field is spread out of MCPG with time due to its low-frequency bias current. To obtain a more effectively distributed bias magnetic field as well as to improve the voltage breakdown between electrodes, the MCPG incorporates a novel ~ 1 mm thick copper shell mounted outside of the outer electrode. This allows for reliable and controlled operation and more robust CT generation. A detailed discussion of the copper shell and experimental test results will be presented.

  18. Development of Compact Toroid Injector for C-2 FRCs

    Science.gov (United States)

    Matsumoto, Tadafumi; Sekiguchi, Junichi; Asai, Tomohiko; Gota, Hiroshi; Garate, Eusebio; Allfrey, Ian; Valentine, Travis; Smith, Brett; Morehouse, Mark; TAE Team

    2014-10-01

    Collaborative research project with Tri Alpha Energy has been started and we have developed a new compact toroid (CT) injector for the C-2 device, mainly for fueling field-reversed configurations (FRCs). The CT is formed by a magnetized coaxial plasma-gun (MCPG), which consists of coaxial cylinder electrodes; a spheromak-like plasma is generated by discharge and pushed out from the gun by Lorentz force. The inner diameter of outer electrode is 83.1 mm and the outer diameter of inner electrode is 54.0 mm. The surface of the inner electrode is coated with tungsten in order to reduce impurities coming out from the electrode. The bias coil is mounted inside of the inner electrode. We have recently conducted test experiments and achieved a supersonic CT translation speed of up to ~100 km/s. Other typical plasma parameters are as follows: electron density ~ 5 × 1021 m-3, electron temperature ~ 40 eV, and the number of particles ~0.5-1.0 × 1019. The CT injector is now planned to be installed on C-2 and the first CT injection experiment will be conducted in the near future. The detailed MCPG design as well as the test experimental results will be presented.

  19. Studies on Plasmoid Merging using Compact Toroid Injectors

    Science.gov (United States)

    Allfrey, Ian; Matsumoto, Tadafumi; Roche, Thomas; Gota, Hiroshi; Edo, Takahiro; Asai, Tomohiko; Sheftman, Daniel; Osin Team; Dima Team

    2017-10-01

    C-2 and C-2U experiments have used magnetized coaxial plasma guns (MCPG) to inject compact toroids (CTs) for refueling the long-lived advanced beam-driven field-reversed configuration (FRC) plasma. This refueling method will also be used for the C-2W experiment. To minimize momentum transfer from the CT to the FRC two CTs are injected radially, diametrically opposed and coincident in time. To improve understanding of the CT characteristics TAE has a dedicated test bed for the development of CT injectors (CTI), where plasmoid merging experiments are performed. The test bed has two CTIs on axis with both axial and transverse magnetic fields. The 1 kG magnetic fields, intended to approximate the magnetic field strength and injection angle on C-2W, allow studies of cross-field transport and merging. Both CTIs are capable of injecting multiple CTs at up to 1 kHz. The resulting merged CT lives >100 μs with a radius of 25 cm. More detailed results of CT parameters will be presented.

  20. Validation of Helium Inlet Design for ITER Toroidal Field Coil

    CERN Document Server

    Boyer, C; Hamada, K; Foussat, A; Le Rest, M; Mitchell, N; Decool, P; Savary, F; Sgobba, S; Weiss, K-P

    2014-01-01

    The ITER organization has performed design and its validation tests on a helium inlet structure for the ITER Toroidal Field (TF) coil under collaboration with CERN, KIT, and CEA-Cadarache. Detailed structural analysis was performed in order to optimize the weld shape. A fatigue resistant design on the fillet weld between the shell covers and the jacket is an important point on the helium inlet structure. A weld filler material was selected based on tensile test at liquid helium temperature after Nb3Sn reaction heat treatment. To validate the design of the weld joint, fatigue tests at 7 K were performed using heat-treated butt weld samples. A pressure drop measurement of a helium inlet mock-up was performed by using nitrogen gas at room temperature in order to confirm uniform flow distribution and pressure drop characteristic. These tests have validated the helium inlet design. Based on the validation, Japanese and European Union domestic agencies, which have responsibilities of the TF coil procurement, are pr...

  1. Superconducting toroidal field coil current densities for the TFCX

    International Nuclear Information System (INIS)

    Kalsi, S.S.; Hooper, R.J.

    1985-04-01

    A major goal of the Tokamak Fusion Core Experiment (TFCX) study was to minimize the size of the device and achieve lowest cost. Two key factors influencing the size of the device employing superconducting magnets are toroidal field (TF) winding current density and its nuclear heat load withstand capability. Lower winding current density requires larger radial build of the winding pack. Likewise, lower allowable nuclear heating in the winding requires larger shield thickness between the plasma and coil. In order to achieve a low-cost device, it is essential to maximize the winding's current density and nuclear heating withhstand capability. To meet the above objective, the TFCX design specification adopted as goals a nominal winding current density of 3500 A/cm 2 with 10-T peak field at the winding and peak nuclear heat load limits of 1 MW/cm 3 for the nominal design and 50 MW/cm 3 for an advanced design. This study developed justification for these current density and nuclear heat load limits

  2. Harmonic moment dynamics in Laplacian growth

    Science.gov (United States)

    Leshchiner, Alexander; Thrasher, Matthew; Mineev-Weinstein, Mark B.; Swinney, Harry L.

    2010-01-01

    Harmonic moments are integrals of integer powers of z=x+iy over a domain. Here, the domain is an exterior of a bubble of air growing in an oil layer between two horizontal closely spaced plates. Harmonic moments are a natural basis for such Laplacian growth phenomena because, unlike other representations, these moments linearize the zero surface tension problem [S. Richardson, J. Fluid Mech. 56, 609 (1972)], so that all moments except the lowest one (the area of the bubble) are conserved in time. In our experiments, we directly determine the harmonic moments and show that for nonzero surface tension, all moments (except the lowest one) decay in time rather than exhibiting the divergences of other representations. Further, we derive an expression that relates the derivative of the kth harmonic moment Mk to measurable quantities (surface tension, viscosity, the distance between the plates, and a line integral over the contour encompassing the growing bubble). The laboratory observations are in good accord with the expression we derive for dMk/dt , which is proportional to the surface tension; thus in the zero surface tension limit, the moments (above k=0 ) are all conserved, in accord with Richardson’s theory. In addition, from the measurements of the time evolution of the harmonic moments we obtain a value for the surface tension that is within 20% of the accepted value. In conclusion, our analysis and laboratory observations demonstrate that an interface dynamics description in terms of harmonic moments is physically realizable and robust.

  3. Inductive Eigenmodes of a resistive toroidal surface in vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Lo Surdo, C. [ENEA, Centro Ricerche Frascati, Rome (Italy). Dipt. Innovazione

    1999-07-01

    In this paper it has been studied the Electro-Magnetic (EM) Eigenmodes, sufficiently slow as to legitimate the pre-Maxwell approximation of Maxwell's system (or inductive Eigenmodes), of a given smooth, toroidal-un knotted, electrically resistive surface {tau} with given smooth (surface) resistivity 0 < {rho}{sub d}egree < {infinity}, and lying in the (empty) R{sup 3}. Within the above limitations (to be made more precise), the geometry of {tau} is arbitrary. With the eigenvalue associated with the generic Eigenmode being defined as the opposite of its logarithmic time-derivative, one expects that the resulting spectrum be discrete and strictly positive. It shall be interested into the degenerate case where {tau} be cut (i.e. electrically broken) along one or more of its irreducible cycles. This case will be analyzed autonomously, rather than as a limit (for {rho}{sub d}egree {yields} {infinity} along the cuts) of the regular case. Without cuts, the Eigenproblem under consideration is nothing but the two-dimensional (2-dim) generalization of the classical case of a smooth, unknotted, electrically conductive, simple coil in infinite vacuum. Its analysis hinges on the classical potential theory, and turns out to be a special application of the linear, integrodifferential (elliptic) equation theory on a compact, multiply connected, 2-dim manifold. The attention and approach will be confined to strong (or classical) solutions, both in {tau} and C {tau} = R{sup 3} / {tau}. This study is divided in two parts: a General Part (Sects 1 divided 4) is devoted to the case of generic {tau} and {rho}{sub d}egree (within the convenient smoothness requirements), whereas a Special Part (Sects 5 divided 7) deals with the (more or less formal) discussion of a couple of particular cases ({tau} {identical_to} a canonical torus), both of which with uniform {rho}{sub d}egree. Some propaedeutical/supplementary information is provided in a number of Appendices. [Italian] Il presente

  4. JT-60SA Toroidal Field Coils test cryostat development

    Energy Technology Data Exchange (ETDEWEB)

    Jamotton, Pierre, E-mail: pjamotton@ulg.ac.be [Centre Spatial de Liège (CSL), Université de Liège Avenue du Pré-Aily, B-4031 Angleur (Belgium); Wanner, Manfred [F4E Broader Fusion Development Dept., Boltzmannstr. 2, D-85748 Garching (Germany); Massaut, Vincent [SCK/CEN, Boeretang 200 2400 Mol (Belgium); Génini, Laurent; Maksoud, Walid Abdel [CEA/DSM/IRFU CEA-Saclay, F-91191 Gif-sur-Yvette Cedex (France); Collin, Bill; Delrez, Christophe [Ateliers de la Meuse (ALM), Rue Ernest Solvay, 107, B-4000 Sclessin (Belgium)

    2013-10-15

    Highlights: ► Large vacuum vessels. ► FEM mechanical design. ► Cryogenic thermal design. ► Full development process: design, manufacturing, assembly, test. -- Abstract: Within the Broader Approach Agreement, Fusion for Energy will deliver to the Japanese Atomic Energy Association, amongst other components, the 18 Toroidal Field Coils (TFCs) for the superconducting Tokamak JT-60SA [1]. These coils will be individually tested at cryogenic temperatures and at the nominal current in a test cryostat. This cryostat is provided as an in-kind contribution by Belgium and is being developed jointly with CEA-Saclay/France. The vessel is large, oval shaped with an overall length of 11 m, a width of 7.2 m and a height of 6.5 m. To reduce the heat load to the coils the cryostat is covered by LN{sub 2} cooled thermal shields. In addition to the cryostat, three test frames for the coils, the valve box vessel and the insulation vacuum system are also provided by Belgium. The Belgian contribution is design, manufacturing, assembly and test of the vacuum chamber, thermal shield and test frames by the Belgian company Ateliers de la Meuse (ALM), with the support of Centre Spatial de Liège (CSL). The TF coil test facility is assembled and the coil tests are performed by CEA/Saclay. The Belgian contribution, namely the design, manufacturing, assembly and test of the vacuum vessel, the thermal shields, and the test frames as well as of the vacuum pumping system are described in the presentation.

  5. Inductive Eigenmodes of a resistive toroidal surface in vacuum

    International Nuclear Information System (INIS)

    Lo Surdo, C.

    1999-01-01

    In this paper it has been studied the Electro-Magnetic (EM) Eigenmodes, sufficiently slow as to legitimate the pre-Maxwell approximation of Maxwell's system (or inductive Eigenmodes), of a given smooth, toroidal-unknotted, electrically resistive surface Τ with given smooth (surface) resistivity 0 d egree 3 . Within the above limitations (to be made more precise), the geometry of Τ is arbitrary. With the eigenvalue associated with the generic Eigenmode being defined as the opposite of its logarithmic time-derivative, one expects that the resulting spectrum be discrete and strictly positive. It shall be interested into the degenerate case where Τ be cut (i.e. electrically broken) along one or more of its irreducible cycles. This case will be analyzed autonomously, rather than as a limit (for ρ d egree → ∞ along the cuts) of the regular case. Without cuts, the Eigenproblem under consideration is nothing but the two-dimensional (2-dim) generalization of the classical case of a smooth, unknotted, electrically conductive, simple coil in infinite vacuum. Its analysis hinges on the classical potential theory, and turns out to be a special application of the linear, integrodifferential (elliptic) equation theory on a compact, multiply connected, 2-dim manifold. The attention and approach will be confined to strong (or classical) solutions, both in Τ and C Τ = R 3 / Τ. This study is divided in two parts: a General Part (Sects 1 divided 4) is devoted to the case of generic Τ and ρ d egree (within the convenient smoothness requirements), whereas a Special Part (Sects 5 divided 7) deals with the (more or less formal) discussion of a couple of particular cases (Τ ≡ a canonical torus), both of which with uniform ρ d egree. Some propaedeutical/supplementary information is provided in a number of Appendices [it

  6. Toroidal reactor designs as a function of aspect ratio

    International Nuclear Information System (INIS)

    Wong, C.P.C.; Wesley, J.C.; Stambaugh, R.D.; Cheng, E.T.

    2001-01-01

    This paper presents a 'common basis' systems study of superconducting (SC) and normal-conducting (NC) DT-burning fusion power and materials testing reactor designs. Figures-of-merit for power and materials-testing reactors are respectively; projected cost-of-electricity (COE) and direct cost (DC). A common 0-D plasma modeling basis is used and the plasma geometry and engineering aspects of the SC and NC designs are treated in an equivalent manner that is consistent with the limitations of their respective magnet technologies and other design constraints. Aspect ratios A in the range 1.2≤A≤6 and plasma elongations in the range 1≤κ≤3 are explored and a MHD stability (beta limit) physics basis that accurately describes the increase of normalized beta β N and toroidal beta β T with a decreasing A and/or increasing κ is incorporated. With this MHD basis taken into account and with the usual reactor geometry, physics and engineering constraints and costing bases applied, the results of the study show that for power reactors the minimum COE is pointing towards lower A∼2 than generally found in previous studies. The minimum is broader with higher κ. For test reactors with similar fusion power output, the direct cost for NC options is significantly lower than for SC coil options. With the NC category, testing designs that combine intermediate A and higher elongation show promise as a D-T burn next step device that could provide scientific and testing data to support future SC and NC reactors. For example, a NC coil design with A∼2, κ=3 could produce 200 MW fusion power at 1.23MW/m 2 average neutron wall loading at a total direct cost of about $643 M. This NC design with a fissile blanket could also convert ∼1270kg of fission reactor waste per full power year. (author)

  7. Flow balancing orifice for ITER toroidal field coil

    Science.gov (United States)

    Litvinovich, A. V.; Y Rodin, I.; Kovalchuk, O. A.; Safonov, A. V.; Stepanov, D. B.; Guryeva, T. M.

    2017-12-01

    Flow balancing orifices (FBOs) are used in in International thermonuclear experimental reactor (ITER) Toroidal Field coil to uniform flow rate of cooling gas in the side double pancakes which have a different conductor length: 99 m and 305 m, respectively. FBOs consist of straight parts, elbows produced from a 316L stainless steel tube 21.34 x 2.11 mm and orifices made from a 316L stainless steel rod. Each of right and left FBOs contains 6 orifices, straight FBOs contain 4 and 6 orifices. Before manufacturing of qualification samples D.V. Efremov Institute of Electrophysical Apparatus (JSC NIIEFA) proposed to ITER a new approach to provide the seamless connection between a tube and a plate therefore the most critical weld between the orifice with 1 mm thickness and the tube removed from the FBOs final design. The proposed orifice diameter is three times less than the minimum requirement of the ISO 5167, therefore it was tasked to define accuracy of calculation flow characteristics at room temperature and compare with the experimental data. In 2015 the qualification samples of flow balancing orifices were produced and tested. The results of experimental data showed that the deviation of calculated data is less than 7%. Based on this result and other tests ITER approved the design of FBOs, which made it possible to start the serial production. In 2016 JSC NIIEFA delivered 50 FBOs to ITER, i.e. 24 left side, 24 right side and 2 straight FBOs. In order to define the quality of FBOs the test facility in JSC NIIEFA was prepared. The helium tightness test at 10-9 m3·Pa/s the pressure up to 3 MPa, flow rate measuring at the various pressure drops, the non-destructive tests of orifices and weld seams (ISO 5817, class B) were conducted. Other tests such as check dimensions and thermo cycling 300 - 80 - 300 K also were carried out for each FBO.

  8. Pinch effects and chaotic motion in toroidal confinement devices

    Energy Technology Data Exchange (ETDEWEB)

    Spizzo, G.; White, R. B.; Cappello, S.; Marrelli, L.; Sattin, F.

    2007-07-01

    Particle transport in toroidal confinement devices is often described in terms of a diffusion constant and an inward pinch velocity: this phenomenological description can be justified by a probabilistic approach (random walk) that simplifies the particle dynamics when the orbits are small enough compared to the system size. This results in a diffusive expression for particle flux. Then, the convective part of the particle flux can be related, for example, to spatial inhomogeneities in temperature or field curvature. When magnetic chaos is present, but the system is not too far from the stochastic threshold, diffusion and pinch can be actually an expression of the sub diffusive nature of the transport, brought about by the presence of a spectrum of long-distance Levy flights. This effect is shown by numerical modelling of the magnetic structure and associated particle transport in conditions relevant for the reversed-field pinch experiment RFX-mod based at Consorzio RFX, Padova. Simulations reproduce the particle motion through guiding center calculations of particle orbits embedded in the magnetic topology, obtained by 3D MHD simulations (code SpeCyl). Results have been used to produce the probability distribution functions (p.d.f.) of jump lengths and waiting times, providing the kernel to integrate in the Montroll equation, which governs the evolution of particle density in the Continuous-time random walk (CTRW) approach. This means that we obtain a transport equation using the knowledge of the kernel which comes directly from the actual particle dynamics. The difference of behavior between trapped and passing particles has also been considered, and has a relevance comparable to sub diffusion in determining the pinch effect. Similar results can be applied to other systems with chaos induces particle transport, e.g. electron transport in Tokamaks. This work was partially supported by DoE contract No. DE-FG03-94ER54271. (Author)

  9. Spontaneous Thigh Compartment Syndrome

    Directory of Open Access Journals (Sweden)

    Khan, Sameer K

    2011-02-01

    Full Text Available A young man presented with a painful and swollen thigh, without any history of trauma, illness, coagulopathic medication or recent exertional exercise. Preliminary imaging delineated a haematoma in the anterior thigh, without any fractures or muscle trauma. Emergent fasciotomies were performed. No pathology could be identified intra-operatively, or on follow-up imaging. A review of thigh compartment syndromes described in literature is presented in a table. Emergency physicians and traumatologists should be cognisant of spontaneous atraumatic presentations of thigh compartment syndrome, to ensure prompt referral and definitive management of this limb-threatening condition. [West J Emerg Med. 2011;12(1:134-138].

  10. Solving moment hierarchies for chemical reaction networks

    Science.gov (United States)

    Krishnamurthy, Supriya; Smith, Eric

    2017-10-01

    The study of chemical reaction networks (CRN’s) is a very active field. Earlier well-known results (Feinberg 1987 Chem. Enc. Sci. 42 2229, Anderson et al 2010 Bull. Math. Biol. 72 1947) identify a topological quantity called deficiency, for any CRN, which, when exactly equal to zero, leads to a unique factorized steady-state for these networks. No results exist however for the steady states of non-zero-deficiency networks. In this paper, we show how to write the full moment-hierarchy for any non-zero-deficiency CRN obeying mass-action kinetics, in terms of equations for the factorial moments. Using these, we can recursively predict values for lower moments from higher moments, reversing the procedure usually used to solve moment hierarchies. We show, for non-trivial examples, that in this manner we can predict any moment of interest, for CRN’s with non-zero deficiency and non-factorizable steady states.

  11. Solving moment hierarchies for chemical reaction networks.

    Science.gov (United States)

    Krishnamurthy, Supriya; Smith, Eric

    2017-10-20

    The study of chemical reaction networks (CRN's) is a very active field. Earlier well-known results (Feinberg 1987 Chem. Enc. Sci . 42 2229, Anderson et al 2010 Bull. Math. Biol . 72 1947) identify a topological quantity called deficiency, for any CRN, which, when exactly equal to zero, leads to a unique factorized steady-state for these networks. No results exist however for the steady states of non-zero-deficiency networks. In this paper, we show how to write the full moment-hierarchy for any non-zero-deficiency CRN obeying mass-action kinetics, in terms of equations for the factorial moments. Using these, we can recursively predict values for lower moments from higher moments, reversing the procedure usually used to solve moment hierarchies. We show, for nontrivial examples, that in this manner we can predict any moment of interest, for CRN's with non-zero deficiency and non-factorizable steady states.

  12. Muon Dipole Moment Experiments Interpretation and Prospects

    CERN Document Server

    Feng, J L; Shadmi, Y; Feng, Jonathan L; Matchev, Konstantin T.; Shadmi, Yael

    2001-01-01

    We examine the prospects for discovering new physics through muon dipole moments. The current deviation in $g_{\\mu}-2$ may be due entirely to the muon's {\\em electric} dipole moment. We note that the precession frequency in the proposed BNL muon EDM experiment is also subject to a similar ambiguity, but this can be resolved by up-down asymmetry measurements. We then review the theoretical expectations for the muon's electric dipole moment in supersymmetric models.

  13. Electric dipole moment of diatomic molecules

    International Nuclear Information System (INIS)

    Rosato, A.

    1983-01-01

    The electric dipole moment of some diatomic molecules is calculated using the Variational Cellular Method. The results obtained for the CO, HB, HF and LiH molecules are compared with other calculations and with experimental data. It is shown that there is strong dependence of the electric dipole moment with respect to the geometry of the cells. The possibility of fixing the geometry of the problem by giving the experimental value of the dipole moment is discussed. (Author) [pt

  14. Electric dipole moment of diatomic molecules

    International Nuclear Information System (INIS)

    Rosato, A.

    1983-01-01

    The electric dipole moment of some diatomic molecules is calculated using the Variational Cellular Method. The results obtained for the molecules CO, HB, HF and LiH are compared with other calculations and with experimental data. It is shown that there is strong dependence of the electric dipole moment with respect to the geometry of the cells. It is discussed the possibility of fixing the geometry of the problem by giving the experimental value of the dipole moment. (Author) [pt

  15. Resistive toroidal-field coils for tokamak reactors

    International Nuclear Information System (INIS)

    Kalnavarns, J.; Jassby, D.L.

    1980-11-01

    This paper analyzes the optimization of the geometry of resistive TF coils of rectangular bore for tokamak fusion test reactors and practical neutron generators. In examining the trade-offs between geometric parameters and magnetic field for reactors giving a specified neutron wall loading, either the resistive power loss or the lifetime coil cost can be minimized. Aspects of cooling, magnetic stress, and construction are addressed for several reference designs. Bending moment distributions in closed form have been derived for rectangular coils on the basis of the theory of rigid frames. Candidate methods of fabrication and of implementing demountable joints are summarized

  16. Spontaneous Tumor Lysis Syndrome

    Directory of Open Access Journals (Sweden)

    Alicia C. Weeks MD

    2015-08-01

    Full Text Available Tumor lysis syndrome (TLS is a known complication of malignancy and its treatment. The incidence varies on malignancy type, but is most common with hematologic neoplasms during cytotoxic treatment. Spontaneous TLS is thought to be rare. This case study is of a 62-year-old female admitted with multisystem organ failure, with subsequent diagnosis of aggressive B cell lymphoma. On admission, laboratory abnormalities included renal failure, elevated uric acid (20.7 mg/dL, and 3+ amorphous urates on urinalysis. Oliguric renal failure persisted despite aggressive hydration and diuretic use, requiring initiation of hemodialysis prior to chemotherapy. Antihyperuricemic therapy and hemodialysis were used to resolve hyperuricemia. However, due to multisystem organ dysfunction syndrome with extremely poor prognosis, the patient ultimately expired in the setting of a terminal ventilator wean. Although our patient did not meet current TLS criteria, she required hemodialysis due to uric acid nephropathy, a complication of TLS. This poses the clinical question of whether adequate diagnostic criteria exist for spontaneous TLS and if the lack of currently accepted guidelines has resulted in the underestimation of its incidence. Allopurinol and rasburicase are commonly used for prevention and treatment of TLS. Although both drugs decrease uric acid levels, allopurinol mechanistically prevents formation of the substrate rasburicase acts to solubilize. These drugs were administered together in our patient, although no established guidelines recommend combined use. This raises the clinical question of whether combined therapy is truly beneficial or, conversely, detrimental to patient outcomes.

  17. Representation of magnetic fields with toroidal topology in terms of field-line invariants

    International Nuclear Information System (INIS)

    Lewis, H.R.

    1990-01-01

    Beginning with Boozer's representation of magnetic fields with toroidal topology [Phys. Fluids 26, 1288 (1983)], a general formalism is presented for the representation of any magnetic field with toroidal topology in terms of field-line invariants. The formalism is an application to the magnetic field case of results developed recently by Lewis et al. (submitted for publication to J. Phys. A) for arbitrary time-dependent Hamiltonian systems with one degree of freedom. Every magnetic field with toroidal topology can be associated with time-dependent Hamiltonian systems with one degree of freedom and every time-dependent Hamiltonian system with one degree of freedom can be associated with magnetic fields with toroidal topology. In the Hamiltonian context, given any particular function I(q,p,t), Lewis et al. derived those Hamiltonians for which I(q,p,t) is an invariant. In addition, for each of those Hamiltonians, they derived a function canonically conjugate to I(q,p,t) that is also an invariant. They applied this result to the case where I(q,p,t) is expressed as a function of two canonically conjugate functions. This general Hamiltonian formalism provides a basis for representing magnetic fields with toroidal topology in terms of field-line invariants. The magnetic fields usually contain plasma with flow and anisotropic pressure. A class of fields with or without rotational symmetry is identified for which there are magnetic surfaces. The formalism is developed for application to the case of vacuum magnetic fields

  18. Air core poloidal magnetic field system for a toroidal plasma producing device

    International Nuclear Information System (INIS)

    Marcus, F.B.

    1978-01-01

    A poloidal magnetics system for a plasma producing device of toroidal configuration is provided that reduces both the total volt-seconds requirement and the magnitude of the field change at the toroidal field coils. The system utilizes an air core transformer wound between the toroidal field (TF) coils and the major axis outside the TF coils. Electric current in the primary windings of this transformer is distributed and the magnetic flux returned by air core windings wrapped outside the toroidal field coils. A shield winding that is closely coupled to the plasma carries a current equal and opposite to the plasma current. This winding provides the shielding function and in addition serves in a fashion similar to a driven conducting shell to provide the equilibrium vertical field for the plasma. The shield winding is in series with a power supply and a decoupling coil located outside the TF coil at the primary winding locations. The present invention requires much less energy than the usual air core transformer and is capable of substantially shielding the toroidal field coils from poloidal field flux

  19. Approximations to the non-adiabatic particle response in toroidal geometry

    International Nuclear Information System (INIS)

    Schep, T.J.; Braams, B.J.

    1981-08-01

    The non-adiabatic part of the particle response to low-frequency electromagnetic modes with long parallel wavelengths is discussed. Analytic approximations to the kernels of the integrals that relate the amplitudes of the perturbed potentials to the non-adiabatic part of the perturbed density in an axisymmetric toroidal configuration are presented and the results are compared with numerical calculations. It is shown that both in the plane slab and in toroidal geometry the kernel contains a logarithmic singularity. This singularity is associated with particles with vanishing parallel velocity so that, in toroidal geometry, it is related with the behaviour of trapped particles near their turning points. In contrast to the plane slab, in toroidal geometry this logarithmic singularity is mainly real and associated with non-resonant particles. Apart from this logarithmic term, the kernel contains a complex regular part arising from resonant as well as from non-resonant particles. The analytic approximations that will be presented make the dispersion relation of drift-type modes in toroidal geometry amenable to analytic as well as to simpler numerical calculation of the growth rate and of the spatial mode structure

  20. INSTABILITY OF NON-UNIFORM TOROIDAL MAGNETIC FIELDS IN ACCRETION DISKS

    Energy Technology Data Exchange (ETDEWEB)

    Hirabayashi, Kota; Hoshino, Masahiro, E-mail: hirabayashi-k@eps.s.u-tokyo.ac.jp [Department of Earth and Planetary Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2016-05-10

    We present a new type of instability that is expected to drive magnetohydrodynamic (MHD) turbulence from a purely toroidal magnetic field in an accretion disk. It is already known that in a differentially rotating system, the uniform toroidal magnetic field is unstable due to magnetorotational instability (MRI) under a non-axisymmetric and vertical perturbation, while it is stable under a purely vertical perturbation. Contrary to the previous study, this paper proposes an unstable mode completely confined to the equatorial plane, driven by the expansive nature of the magnetic pressure gradient force under a non-uniform toroidal field. The basic nature of this growing eigenmode, which we name “magneto-gradient driven instability,” is studied using linear analysis, and the corresponding nonlinear evolution is then investigated using two-dimensional ideal MHD simulations. Although a single localized magnetic field channel alone cannot provide sufficient Maxwell stress to contribute significantly to the angular momentum transport, we find that the mode coupling between neighboring toroidal fields under multiple localized magnetic field channels drastically generates a highly turbulent state and leads to the enhanced transport of angular momentum, which is comparable to the efficiency seen in previous studies on MRIs. This horizontally confined mode may play an important role in the saturation of an MRI through complementray growth with the toroidal MRIs and coupling with magnetic reconnection.

  1. Observations of toroidal and poloidal rotation in the high beta tokamak Torus II

    International Nuclear Information System (INIS)

    Kostek, C.A.

    1983-01-01

    The macroscopic rotation of plasma in a toroidal containment device is an important feature of the equilibrium. Toroidal and poloidal rotation in the high beta tokamak Torus II is measured experimentally by examining the Doppler shift of the 4685.75 A He II line emitted from the plasma. The toroidal flow at an average velocity of 1.6 x 10 6 cm/sec, a small fraction of the ion thermal speed, moves in the same direction as the toroidal plasma current. The poloidal flow follows the ion diamagnetic current direction, also at an average speed of 1.6 x 10 6 cm/sec. In view of certain ordering parameters, the toroidal flow is compared with predictions from neoclassical theory in the collosional, Pfirsch-Schluter regime. The poloidal motion, however results from an E x B drift in a positive radial electric field, approaching a stable ambipolar state. This radial electric field is determined from theory by using the measured poloidal velocity. Mechanisms for the time evolution of rotation are also examined. It appears that the circulation damping is governed by a global decay of the temperature and density gradients which, in turn, may be functions of radiative cooling, loss of equilibrium due to external field decay, or the emergence of a growing instability, occasionally observed in CO 2 interferometry measurements

  2. The neutron electric dipole moment

    International Nuclear Information System (INIS)

    He, X.G.; McKellar, B.H.J.; Pakvasa, S.

    1989-01-01

    A systematic study was made of the electric dipole moment (EDM) of neutron D n in various models of CP violation. It was found that in the standard KM model with 3 families the neutron EDM is in the range 1.4x10 -33 ≤ D n ≤ 1.6x10 -31 ecm; that the two Higgs doublet model has approximately the same value of D n as the standard model; that D n in the Weinberg model is predicted to satisfy D n > 10 -25 ecm; that in a class of left-right symmetric models D n is of the order of 10 -26-11 ecm; that in supersymmetric models D n is of the order 10 -22 φ ecm with φ being the possible phase difference of the phases of gluino mass and the gluino-quark-smark mixing matrix and that the strong CP parameter θ is found to be θ -9 , using the present experimental limit that D n -25 ecm with 90% confidence. 65 refs., 10 figs

  3. Stereo Correspondence Using Moment Invariants

    Science.gov (United States)

    Premaratne, Prashan; Safaei, Farzad

    Autonomous navigation is seen as a vital tool in harnessing the enormous potential of Unmanned Aerial Vehicles (UAV) and small robotic vehicles for both military and civilian use. Even though, laser based scanning solutions for Simultaneous Location And Mapping (SLAM) is considered as the most reliable for depth estimation, they are not feasible for use in UAV and land-based small vehicles due to their physical size and weight. Stereovision is considered as the best approach for any autonomous navigation solution as stereo rigs are considered to be lightweight and inexpensive. However, stereoscopy which estimates the depth information through pairs of stereo images can still be computationally expensive and unreliable. This is mainly due to some of the algorithms used in successful stereovision solutions require high computational requirements that cannot be met by small robotic vehicles. In our research, we implement a feature-based stereovision solution using moment invariants as a metric to find corresponding regions in image pairs that will reduce the computational complexity and improve the accuracy of the disparity measures that will be significant for the use in UAVs and in small robotic vehicles.

  4. An Evolutionary Game Theory Model of Spontaneous Brain Functioning.

    Science.gov (United States)

    Madeo, Dario; Talarico, Agostino; Pascual-Leone, Alvaro; Mocenni, Chiara; Santarnecchi, Emiliano

    2017-11-22

    Our brain is a complex system of interconnected regions spontaneously organized into distinct networks. The integration of information between and within these networks is a continuous process that can be observed even when the brain is at rest, i.e. not engaged in any particular task. Moreover, such spontaneous dynamics show predictive value over individual cognitive profile and constitute a potential marker in neurological and psychiatric conditions, making its understanding of fundamental importance in modern neuroscience. Here we present a theoretical and mathematical model based on an extension of evolutionary game theory on networks (EGN), able to capture brain's interregional dynamics by balancing emulative and non-emulative attitudes among brain regions. This results in the net behavior of nodes composing resting-state networks identified using functional magnetic resonance imaging (fMRI), determining their moment-to-moment level of activation and inhibition as expressed by positive and negative shifts in BOLD fMRI signal. By spontaneously generating low-frequency oscillatory behaviors, the EGN model is able to mimic functional connectivity dynamics, approximate fMRI time series on the basis of initial subset of available data, as well as simulate the impact of network lesions and provide evidence of compensation mechanisms across networks. Results suggest evolutionary game theory on networks as a new potential framework for the understanding of human brain network dynamics.

  5. Spontaneous Intracranial Hypotension

    International Nuclear Information System (INIS)

    Joash, Dr.

    2015-01-01

    Epidemiology is not only rare but an important cause of new daily persistent headaches among young & middle age individuals. The Etiology & Pathogenesis is generally caused by spinal CSF leak. Precise cause remains largely unknown, underlying structural weakness of spinal meninges is suspected. There are several MR Signs of Intracranial Hypotension that include:- diffuse pachymeningeal (dural) enhancement; bilateral subdural, effusion/hematomas; Downward displacement of brain; enlargement of pituitary gland; Engorgement of dural venous sinuses; prominence of spinal epidural venous plexus and Venous sinus thrombosis & isolated cortical vein thrombosis. The sum of volumes of intracranial blood, CSF & cerebral tissue must remain constant in an intact cranium. Treatment in Many cases can be resolved spontaneously or by use Conservative approach that include bed rest, oral hydration, caffeine intake and use of abdominal binder. Imaging Modalities for Detection of CSF leakage include CT myelography, Radioisotope cisternography, MR myelography, MR imaging and Intrathecal Gd-enhanced MR

  6. Spontaneous wave packet reduction

    International Nuclear Information System (INIS)

    Ghirardi, G.C.

    1994-06-01

    There are taken into account the main conceptual difficulties met by standard quantum mechanics in dealing with physical processes involving macroscopic system. It is stressed how J.A.Wheeler's remarks and lucid analysis have been relevant to pinpoint and to bring to its extreme consequences the puzzling aspects of quantum phenomena. It is shown how the recently proposed models of spontaneous dynamical reduction represent a consistent way to overcome the conceptual difficulties of the standard theory. Obviously, many nontrivial problems remain open, the first and more relevant one being that of generalizing the model theories considered to the relativistic case. This is the challenge of the dynamical reduction program. 43 refs, 2 figs

  7. Statistical Inference Based on L-Moments

    Directory of Open Access Journals (Sweden)

    Tereza Šimková

    2017-03-01

    Full Text Available To overcome drawbacks of central moments and comoment matrices usually used to characterize univariate and multivariate distributions, respectively, their generalization, termed L-moments, has been proposed. L-moments of all orders are defined for any random variable or vector with finite mean. L-moments have been widely employed in the past 20 years in statistical inference. The aim of the paper is to present the review of the theory of L-moments and to illustrate their application in parameter estimating and hypothesis testing. The problem of estimating the three-parameter generalized Pareto distribution’s (GPD parameters that is generally used in modelling extreme events is considered. A small simulation study is performed to show the superiority of the L-moment method in some cases. Because nowadays L-moments are often employed in estimating extreme events by regional approaches, the focus is on the key assumption of index-flood based regional frequency analysis (RFA, that is homogeneity testing. The benefits of the nonparametric L-moment homogeneity test are implemented on extreme meteorological events observed in the Czech Republic.

  8. 6-quark contribution to nuclear magnetic moments

    International Nuclear Information System (INIS)

    Ito, H.

    1985-01-01

    The magnetic moments of nuclei with LS closed shell +/-1 particle are calculated. Core polarization and meson exchange current are treated realistically in order to single out the 6-quark contribution. Overall agreement with experimental values is quite good. It is shown that the 6-quark system contributes to the respective iso-vector and iso-scalar moments with reasonable magnitudes

  9. Closed forms and multi-moment maps

    DEFF Research Database (Denmark)

    Madsen, Thomas Bruun; Swann, Andrew Francis

    We extend the notion of multi-moment map to geometries defined by closed forms of arbitrary degree. We give fundamental existence and uniqueness results and discuss a number of essential examples, including geometries related to special holonomy. For forms of degree four, multi-moment maps...

  10. Fixed-J moments: exact calculations

    International Nuclear Information System (INIS)

    Jacquemin, C.

    1980-01-01

    We show that the two first fixed J moments of the Hamiltonian operator can be easily calculated over the whole fixed particle number shell model space as well as over configurations. The method may be extended to higher moments of H and to include the isotopic spin T

  11. Closed forms and multi-moment maps

    DEFF Research Database (Denmark)

    Madsen, T. B.; Swann, A.

    2013-01-01

    We extend the notion of multi-moment map to geometries defined by closed forms of arbitrary degree. We give fundamental existence and uniqueness results and discuss a number of essential examples, including geometries related to special holonomy. For forms of degree four, multi-moment maps are gu...

  12. Real object recognition using moment invariants

    Indian Academy of Sciences (India)

    contour-based shape descriptors and region-based shape descriptors (Kim & Sung 2000). Regular moment invariants are one of the most popular and widely used contour-based shape descriptors is a set of derived by Hu (1962). These geometrical moment invariants have been then extended to larger sets by Wong & Siu ...

  13. Optimization of Shielded PCB Air-Core Toroids for High-Efficiency DC-DC Converters

    CERN Document Server

    Orlandi, S; Buso, S; Michelis, S; Fuentes, C A; Kayal, M; Faccio, F; Spiazzi, G

    2011-01-01

    The paper describes the design of optimized printed circuit board (PCB) air-core toroids for high-frequency dc-dc converters with strict requirements in terms of volume and noise. The effect of several design parameters on the overall inductor volume, on dc and ac winding resistance, and on the radiated noise will be investigated. PCB toroids are compared to standard air-core solenoids and other state-of-the-art air-core toroids both theoretically and experimentally: at first, using ANSOFT Maxwell and ANSOFT Q3D simulation tools, and subsequently, with laboratory measurements (irradiated noise, efficiency, and frequency response) on several prototypes. These very flexible and rather easy to manufacture inductors appear very attractive for compact high-frequency dc-dc converters where high efficiency, low volume, and low noise are of primary concern.

  14. Neoclassical Drift of Circulating Orbits Due toToroidal Electric Field in Tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Qin; Guan, Xiaoyin; Fisch, Nathaniel J.

    2011-07-19

    In tokamaks, Ware pinch is a well known neoclassical effect for trapped particles in response to a toroidal electric field. It is generally believed that there exists no similar neoclassical effect for circulating particles without collisions. However, this belief is erroneous, and misses an important effect. We show both analytically and numerically that under the influence of a toroidal electric field parallel to the current, the circulating orbits drift outward toward the outer wall with a characteristic velocity O ({var_epsilon}{sup -1}) larger than the E x B velocity, where {var_epsilon} is the inverse aspect-ratio of a tokamak. During a RF overdrive, the toroidal electric field is anti-parallel to the current. As a consequence, all charged particles, including backward runaway electrons, will drift inward towards the inner wall.

  15. Co-toroidal plasma rotation with electron cyclotron power in DIII-D

    International Nuclear Information System (INIS)

    Grassie, J.S. de; Baker, D.R.; Luce, T.C.; Petty, C.C.; Prater, R.; Brennan, D.

    2001-01-01

    RF electron heating and current drive in DIII-D are observed to typically reduce the core toroidal rotation velocity and core ion temperature when added to target discharges with rotation established by neutral beam heating. Two cases are noted here in which electron cyclotron heating and current drive are observed to increase co-toroidal rotation in different discharge regimes. In the first case electron cyclotron current drive (ECCD) is used to stabilize a 3/2 neoclassical tearing mode (NTM) and the stabilization is accompanied by an increase in rotation, ion temperature and plasma beta. In the second case electron cyclotron heating (ECH) added to a nominally Ohmic target discharge results in an increase in the co-toroidal rotation

  16. Passing particle toroidal precession induced by electric field in a tokamak

    International Nuclear Information System (INIS)

    Andreev, V. V.; Ilgisonis, V. I.; Sorokina, E. A.

    2013-01-01

    Characteristics of a rotation of passing particles in a tokamak with radial electric field are calculated. The expression for time-averaged toroidal velocity of the passing particle induced by the electric field is derived. The electric-field-induced additive to the toroidal velocity of the passing particle appears to be much smaller than the velocity of the electric drift calculated for the poloidal magnetic field typical for the trapped particle. This quantity can even have the different sign depending on the azimuthal position of the particle starting point. The unified approach for the calculation of the bounce period and of the time-averaged toroidal velocity of both trapped and passing particles in the whole volume of plasma column is presented. The results are obtained analytically and are confirmed by 3D numerical calculations of the trajectories of charged particles

  17. Neoclassical Drift of Circulating Orbits Due toToroidal Electric Field in Tokamaks

    International Nuclear Information System (INIS)

    Qin, Hong; Guan, Xiaoyin; Fisch, Nathaniel J.

    2011-01-01

    In tokamaks, Ware pinch is a well known neoclassical effect for trapped particles in response to a toroidal electric field. It is generally believed that there exists no similar neoclassical effect for circulating particles without collisions. However, this belief is erroneous, and misses an important effect. We show both analytically and numerically that under the influence of a toroidal electric field parallel to the current, the circulating orbits drift outward toward the outer wall with a characteristic velocity O ((var e psilon) -1 ) larger than the E x B velocity, where (var e psilon) is the inverse aspect-ratio of a tokamak. During a RF overdrive, the toroidal electric field is anti-parallel to the current. As a consequence, all charged particles, including backward runaway electrons, will drift inward towards the inner wall.

  18. Stabilization of pressure-driven external modes in tokamaks with a resistive wall and toroidal rotation

    International Nuclear Information System (INIS)

    Ward, D.J.; Bondeson, A.

    1994-01-01

    In recent work we have shown that it is possible to completely stabilize low n, pressure-driven external modes in tokamaks by the combined effect of resistive walls and toroidal plasma rotation. We have used numerical computation to study the wall stabilization in toroidal geometry. The spectral codes MARS and NOVA have been modified to include a resistive shell in the vacuum region surrounding the plasma. Rigid toroidal rotation was modeled by making the resistive shell rotate with an externally imposed frequency ω rot while the equilibrium was static. The plasma was treated as ideally conducting and ω rot was some fraction of the sound frequency. Furthermore, the time-constant of the resistive wall, τ ω , was taken much larger than any ideal-MHD timescale. (author) 4 figs., 6 refs

  19. The control on the deformation of the ATLAS barrel toroid warm structure

    CERN Document Server

    Bauer, F; Giraud, P F; Védrine, P; Guyot, C; Levesy, B; Ponsot, P; Schune, P; Sun, Z

    2007-01-01

    The ATLAS barrel toroid warm structure supports the barrel toroid and the muon detectors. The warm structure is about 26 meters long with an outer diameter of 20 meters. In order to ensure the physics performance of the muon detectors, the deformation of the warm structure is minimised during the design phase. The barrel toroid assembly has been carried out in the cavern of the ATLAS experiment since end of 2004. In September 2005, the warm structure has been completely released. The release has been followed-up in real time using optical alignment sensors. Good agreement has been found within 1 mm, between the alignment system measurement, the geometer survey and the predicted values according to the finite element analyses results.

  20. A Mathematical Method for Eliminating Spin Losses in Toroidal Traction Drives

    Directory of Open Access Journals (Sweden)

    Qingtao Li

    2015-01-01

    Full Text Available The efficiency of the original Toroidal continuously variable transmission (CVT is limited due to the spin losses caused by the different speed distribution in the contact area. To overcome this drawback, this paper replaces the original working surface with a new surface derived from a differential equation and proposes a novel Logarithmic CVT. Equations and ranges of the transmission ratio range, half-cone-angle, and conformity ratio, which are essential geometrical parameters of the Logarithmic CVT, are derived. A set of geometrical parameters is further recommended. With such geometrical parameters, the transmission ratio range of the Logarithmic CVT is as wide as that of the Half-Toroidal CVT. The two types of CVTs are compared with each other in terms of efficiency based on a widely accepted computational model. The results show that efficiency of the Logarithmic CVT is higher than that of Half-Toroidal CVT except for some particular situations because of the thrust bearing losses.

  1. Blurred image recognition by legendre moment invariants

    Science.gov (United States)

    Zhang, Hui; Shu, Huazhong; Han, Guo-Niu; Coatrieux, Gouenou; Luo, Limin; Coatrieux, Jean-Louis

    2010-01-01

    Processing blurred images is a key problem in many image applications. Existing methods to obtain blur invariants which are invariant with respect to centrally symmetric blur are based on geometric moments or complex moments. In this paper, we propose a new method to construct a set of blur invariants using the orthogonal Legendre moments. Some important properties of Legendre moments for the blurred image are presented and proved. The performance of the proposed descriptors is evaluated with various point-spread functions and different image noises. The comparison of the present approach with previous methods in terms of pattern recognition accuracy is also provided. The experimental results show that the proposed descriptors are more robust to noise and have better discriminative power than the methods based on geometric or complex moments. PMID:19933003

  2. Measurement of excited state static moments

    International Nuclear Information System (INIS)

    Sergolle, Henri

    Electric quadrupole and magnetic dipole moments are defined from a classical description of the nucleus and a quantum expression is given for the operators. The principal characteristics of the moment interaction with an outer electric or magnetic field are recalled. The study of the perturbed angular distributions of nuclear reaction products allows half-lives of high spin isomer states to be measured (from a few ps to several hours). The decay gamma rays present, under certain conditions, a strong anisotropy; in principle only one detector is sufficient to observe the angular distribution; coincidences are unnecessary and a high counting rate becomes possible. The measurement of the Coulomb excitation probabilities give the electric (dynamic and static) moments and indirectly quadrupolar moments; two techniques are used: the analysis of elastically and inelastically scattered particles and measurement of the deexcitation γ rays in coincidence with the scattered ions. Quadrupole moments can be measured from the precession of the angular distribution [fr

  3. Spontaneous compactification to homogeneous spaces

    International Nuclear Information System (INIS)

    Mourao, J.M.

    1988-01-01

    The spontaneous compactification of extra dimensions to compact homogeneous spaces is studied. The methods developed within the framework of coset space dimensional reduction scheme and the most general form of invariant metrics are used to find solutions of spontaneous compactification equations

  4. Screening for spontaneous preterm birth

    NARCIS (Netherlands)

    van Os, M.A.; van Dam, A.J.E.M.

    2015-01-01

    Preterm birth is the most important cause of perinatal morbidity and mortality worldwide. In this thesis studies on spontaneous preterm birth are presented. The main objective was to investigate the predictive capacity of mid-trimester cervical length measurement for spontaneous preterm birth in a

  5. Hamiltonian guiding center drift orbit calculation for toroidal plasmas of arbitrary cross section

    Energy Technology Data Exchange (ETDEWEB)

    White, R.B.; Chance, M.S.

    1984-02-01

    A Hamiltonian guiding center drift orbit formalism is developed which permits the efficient calculation of particle trajectories in toroidal devices of arbitrary cross section with arbitrary plasma ..beta... The magnetic field is assumed to be a small perturbation from a zero order toroidal equilibrium field possessing either axial or helical symmetry. The equilibrium field can be modelled analytically or obtained numerically from equilibrium codes. A numerical code based on the formalism is used to study particle orbits in circular and bean-shaped tokamak configurations.

  6. Tokamak equilibria with non-parallel flow in a triangularity-deformed axisymmetric toroidal coordinate system

    Directory of Open Access Journals (Sweden)

    Ap Kuiroukidis

    2018-01-01

    Full Text Available We consider a generalized Grad–Shafranov equation (GGSE in a triangularity-deformed axisymmetric toroidal coordinate system and solve it numerically for the generic case of ITER-like and JET-like equilibria with non-parallel flow. It turns out that increase of the triangularity improves confinement by leading to larger values of the toroidal beta and the safety factor. This result is supported by the application of a criterion for linear stability valid for equilibria with flow parallel to the magnetic field. Also, the parallel flow has a weaker stabilizing effect.

  7. High #betta# and toroidal effects on the internal kink mode in tokamaks

    International Nuclear Information System (INIS)

    Schmalz, R.

    1982-09-01

    The inclusion of high-#betta# and first-order toroidal terms in the reduced set of (resistive) MHD equations affords the possibility of improving the study of tokamak plasma behaviour by three-dimensional numerical simulation. A new code, GALA, based on the reduced equations is developed. It is used to analyse the linear and nonlinear behaviour of the internal kink mode in equilibria which are generated by a simple relaxation procedure. We find that the inclusion of toroidal effects in high-#betta# equilibria provides considerable stabilization. (orig.)

  8. A flexible code based on a scalar representation of toroidal MHD

    International Nuclear Information System (INIS)

    Denton, R.E.; Maschke, E.K.; Urquijo, G.

    1994-01-01

    An exact representation of magneto-hydrodynamics in terms of stream functions and potentials allows to write systems of reduced MHD equations of various complexity, depending on the problem to be investigated. Using this feature of the scalar representation, we develop a code for the nonlinear evolution of solutions of arbitrary reduced systems or of the complete MHD equations. The equations are written in general toroidal flux coordinates r, θ, C. In the present phase of development the code solves three evolutions equations for the vorticity density w, the flux Ψ and the pressure p in toroidal or cylindrical geometry. First results on tearing modes will be presented. (authors). 8 refs., 2 figs

  9. Perturbation treatment of the longitudinal coupling impedance of a toroidal beam tube

    International Nuclear Information System (INIS)

    Hahn, H.; Tepikian, S.

    1991-01-01

    A simple analytical expression for the longitudinal coupling impedance of a toroidal beam tube below the resonance region has been derived by expanding the electromagnetic fields of the toroidal beam tube in a power series in curvature and substituting directly into Maxwell's equations. The resulting expression consists of the impedance of the straight beam pipe plus a correction terms due to the curvature. It has been verified that this result gives excellent agreement to the exact solution below the first resonance. 5 refs., 2 figs., 3 tabs

  10. Effect of toroidal plasma flow and flow shear on global MHD modes

    International Nuclear Information System (INIS)

    Chu, M.S.; Greene, J.M.; Jensen, T.H.; Miller, R.L.; Bondeson, A.; Johnson, R.W.; Mauel, M.E.

    1995-01-01

    The effect of a subsonic toroidal flow on the linear magnetohydrodynamic stability of a tokamak plasma surrounded by an external resistive wall is studied. A complex non-self-adjoint eigenvalue problem for the stability of general kink and tearing modes is formulated, solved numerically, and applied to high β tokamaks. Results indicate that toroidal plasma flow, in conjunction with dissipation in the plasma, can open a window of stability for the position of the external wall. In this window, stable plasma beta values can significantly exceed those predicted by the Troyon scaling law with no wall. Computations utilizing experimental data indicate good agreement with observations

  11. Observation of Cocurrent Toroidal Rotation in the EAST Tokamak with Lower-Hybrid Current Drive

    International Nuclear Information System (INIS)

    Shi Yuejiang; Xu Guosheng; Wang Fudi; Wang Mao; Fu Jia; Li Yingying; Zhang Wei; Zhang Wei; Chang Jiafeng; Lv Bo; Qian Jinping; Shan Jiafang; Liu Fukun; Ding Siye; Wan Baonian; Lee, Sang-Gon; Bitter, Manfred; Hill, Kenneth

    2011-01-01

    Lower-hybrid waves have been shown to induce a cocurrent change in toroidal rotation of up to 40 km/s in the L-mode plasma core region and 20 km/s in the edge of the EAST tokamak. This modification of toroidal rotation develops on different time scales. For the edge, the time scale is no more than 100 ms, but for the core the time scale is around 1 s. A simple model based on turbulent equipartition and thermoelectric pinch predicts the experimental results.

  12. Hydrogen transport in a toroidal plasma using multigroup discrete-ordinates methodology

    International Nuclear Information System (INIS)

    Wienke, B.R.; Miller, W.F. Jr.; Seed, T.J.

    1979-01-01

    Neutral hydrogen transport in a fully ionized two-dimensional tokamak plasma was examined using discrete ordinates and contrasted with earlier analyses. In particular, curvature effects induced by toroidal geometries and ray effects caused by possible source localization were investigated. From an overview of the multigroup discrete-ordinates approximation, methodology in two-dimensional cylindrical geometry is detailed, mesh and plasma zoning procedures are sketched, and the piecewise polynomial solution algorithm on a triangular domain is obtained. Toroidal effects and comparisons as related to reaction rates and perticle spectra are examined for various model and source configurations

  13. Considerations of coil protection and electrical connection schemes in large superconducting toroidal magnet system

    International Nuclear Information System (INIS)

    Yeh, H.T.

    1976-03-01

    A preliminary comparison of several different coil protection and electrical connection schemes for large superconducting toroidal magnet systems (STMS) is carried out. The tentative recommendation is to rely on external dump resistors for coil protection and to connect the coils in the toroidal magnet in several parallel loops (e.g., every fourth coil is connected into a single series loop). For the fault condition when a single coil quenches, the quenched coil should be isolated from its loop by switching devices. The magnet, as a whole, should probably be discharged if more than a few coils have quenched

  14. Stability properties of a toroidal z-pinch in an external magnetic multipole field

    International Nuclear Information System (INIS)

    Eriksson, H.G.

    1987-01-01

    MHD stability of m=1, axisymmetric, external modes of a toroidal z-pinch immersed in an external multipole field (Extrap configuration) is studied. The description includes the effects of a weak toroidicity, a non-circular plasma cross-section and the influence of induced currents in the external conductors. It is found that the non-circularity of the plasma cross-section always has a destabilizing effect but that the m=1 mode can be stabilized by the external feedback if the non-circularity is small. (author)

  15. Toroidal Alfvén eigenmode triggered by trapped anisotropic energetic particles in a toroidal resistive plasma with free boundary

    Science.gov (United States)

    Yang, S. X.; Hao, G. Z.; Liu, Y. Q.; Wang, Z. X.; Hu, Y. J.; Zhu, J. X.; He, H. D.; Wang, A. K.

    2018-04-01

    The toroidal Alfvén eigenmode (TAE), excited by trapped energetic particles (EPs), is numerically investigated in a tokamak plasma, using the non-perturbative magnetohydrodynamic-kinetic hybrid formulation based MARS-K code (Liu et al 2008 Phys. Plasmas 15 112503). Compared with the fixed boundary condition at the plasma edge, a free boundary enhances the critical value of the EPs kinetic contribution for driving the TAE. Free boundary also induces finite perturbations at the plasma edge as expected. An anisotropic distribution of EPs, in the particle pitch angle space, strongly enhances the instability and results in a more global mode structure, compared with the isotropic case. The plasma resistivity is also found to play a role in the EPs-destabilized TAE. In particular, the mode stability domain is mapped out, in the 2D parameter space of the plasma resistivity and a quantity defining the width of the particle distribution in pitch angle (for anisotropic distribution). A resonance layer in the poloidal mode structure, with the layer width increasing with the plasma resistivity, appears at the large width of the particle distribution in pitch angle space. A mode conversion, from the modified ideal kink by the EPs kinetic effect to the TAE, is also observed while increasing the birth energy of EPs. Computational results suggest that the TAE mode structure can be modified by certain key plasma parameters, such as the EPs kinetic contribution, the equilibrium pressure, the plasma resistivity, the distribution of EPs, as well as the birth energy of EPs. Such modification of the eigenmode structure can only be obtained following the non-perturbative hybrid approach (Wang et al 2013 Phys. Rev. Lett. 111 145003, Wang et al 2015 Phys. Plasmas 22 022509), as adopted in this study. More importantly, numerical results show that near the marginal stability point, the dominant poloidal harmonics of the TAE overlap with each other, and are localized at the tip positions of

  16. A feasibility study of developing toroidal tanks for a spinning spacecraft. Part 2: Evaluation of fluid behavior in spinning toroidal tanks

    Science.gov (United States)

    Anderson, J. E.

    1974-01-01

    An experimental program was conducted for the purpose of evaluating propellant behavior characteristics in spinning toroidal tanks. The effects of typical mission requirements, and related phenomena upon propellant slosh and settling, and orientation and stability of the ullage were investigated in a subscale model tank under both one-g and low-g acceleration environments. Specific conditions included were axial acceleration, spin rate, spinrate change, and spacecraft wobble, both singly and in combination. Methanol and water in combination with appropriate spin-rates and accelerations of the scale model system were used to simulate the behavior of fluorine, nitrogen tetroxide, monomethylhydrazine, and hydrazine. The experimental results indicate that no major fluid behavior problems would be encountered with the use of toroidal tanks containing any of the four propellants in a proposed spin-stabilized orbiter spacecraft.

  17. Spontaneous Pneumomediastinum: Hamman Syndrome

    Directory of Open Access Journals (Sweden)

    Tushank Chadha, BS

    2018-04-01

    significant fat stranding. The image also showed an intraluminal stent traversing the gastric antrum and gastric pylorus with no indication of obstruction. Circumferential mural thickening of the gastric antrum and body were consistent with the patient’s history of gastric adenocarcinoma. The shotty perigastric lymph nodes with associated fat stranding, along the greater curvature of the distal gastric body suggested local regional nodal metastases and possible peritoneal carcinomatosis. The thoracic CT scans showed extensive pneumomediastinum that tracked into the soft tissues of the neck, which given the history of vomiting also raised concern for esophageal perforation. There was still no evidence of mediastinal abscess or fat stranding. Additionally, a left subclavian vein port catheter, which terminates with tip at the cavoatrial junction of the superior vena cava can also be seen on the image. Discussion: Spontaneous Pneumomediastinum, also known as Hamman syndrome, is defined by the uncommon incidence of free air in the mediastinum due to the bursting of alveoli, as a result of extended spells of shouting, coughing, or vomiting.1,2 The condition is diagnosed when a clear cause (aerodigestive rupture, barotrauma, infection secondary to gas-forming organisms3 for pneumomediastinum cannot be clearly identified on diagnostic studies. Macklin and Macklin were the first to note the pathogenesis of the syndrome and explained that the common denominator to spontaneous pneumomediastinum was that increased alveolar pressure leads to alveolar rupture.3 Common clinical findings for spontaneous pneumomediastinum include: chest pain, dyspnea, cough, and emesis.4 The condition is not always readily recognized on initial presentation in part for its rare incidence, estimated to be approximately 1 in every 44,500 ED patients3and also because of the non-specific presenting symptoms. For this patient, there was no clear singular cause, and therefore she received care for spontaneous

  18. International school of plasma physics course on instabilities and confinement in toroidal plasmas. Varenna (Italy), September 27-October 9, 1971

    International Nuclear Information System (INIS)

    1974-11-01

    The lectures of a Varenna Summer School about the theme Instabilities and Confinement in toroidal Plasmas are given. The topics included are: high-beta toroidal pinches, non-MHD instabilities and anomalous transport, analogy between turbulent transfer in velocity space and plasma collisioned transport in real space, the magnetohydrodynamic approach of plasma confinement in closed magnetic configurations, properties of isodynamical equilibrium configurations and their generalization, transport theory for toroidal plasmas, plasma physics, low-β toroidal machines, the neoclassical theory of transit time magnetic pumping, radio frequency heating of toroidal plasmas, plasma heating at lower hybrid frequency, RF-plasma heating with L-structures, numerical simulation, dynamical stabilization of low frequency waves in inhomogeneous plasmas, dynamic and feedback stabilization of plasmas and problems with nuclear fusion reactors

  19. Toroidally symmetric/asymmetric effect on the divertor flux due to neon/nitrogen seeding in LHD

    Directory of Open Access Journals (Sweden)

    H. Tanaka

    2017-08-01

    Full Text Available Toroidal distributions of divertor particle flux during neon (Ne and nitrogen (N2 seeded discharges were investigated in the Large Helical Device (LHD. By using 14 toroidally distributed divertor probe arrays, which were positioned at radially inner side where the divertor flux concentrates in the inward-shifted magnetic axis configuration, it is found that Ne puffing leads to toroidally quasi-uniform reduction of divertor particle fluxes; whereas toroidally localized reductions were observed with N2 puffing. The toroidally asymmetric reduction pattern with N2 puffing is strongly related to the magnetic field structure around the N2 puffing port. Assuming that nitrogen particles do not recycle, EMC3-EIRENE simulation shows similar reduction pattern with the experiment around the N2 puffing port.

  20. Study of spontaneous fission lifetimes using nuclear density functional theory

    Directory of Open Access Journals (Sweden)

    Sadhukhan Jhilam

    2013-12-01

    Full Text Available The spontaneous fission lifetimes have been studied microscopically by minimizing the collective action integral in a two-dimensional collective space of quadrupole moments (Q20, Q22 representing elongation and triaxiality. The microscopic collective potential and inertia tensor are obtained by solving the self-consistent Hartree-Fock-Bogoliubov (HFB equations with the Skyrme energy density functional and mixed pairing interaction. The mass tensor is computed within the perturbative Adiabatic Time-Dependent HFB (ATDHFB approach in the cranking approximation. The dynamic fission trajectories have been obtained by minimizing the collective action using two different numerical techniques. The values of spontaneous fission lifetimes obtained in this way are compared with the static results.

  1. Toroidal-Core Microinductors Biased by Permanent Magnets

    Science.gov (United States)

    Lieneweg, Udo; Blaes, Brent

    2003-01-01

    The designs of microscopic toroidal-core inductors in integrated circuits of DC-to-DC voltage converters would be modified, according to a proposal, by filling the gaps in the cores with permanent magnets that would apply bias fluxes (see figure). The magnitudes and polarities of the bias fluxes would be tailored to counteract the DC fluxes generated by the DC components of the currents in the inductor windings, such that it would be possible to either reduce the sizes of the cores or increase the AC components of the currents in the cores without incurring adverse effects. Reducing the sizes of the cores could save significant amounts of space on integrated circuits because relative to other integrated-circuit components, microinductors occupy large areas - of the order of a square millimeter each. An important consideration in the design of such an inductor is preventing magnetic saturation of the core at current levels up to the maximum anticipated operating current. The requirement to prevent saturation, as well as other requirements and constraints upon the design of the core are expressed by several equations based on the traditional magnetic-circuit approximation. The equations involve the core and gap dimensions and the magnetic-property parameters of the core and magnet materials. The equations show that, other things remaining equal, as the maximum current is increased, one must increase the size of the core to prevent the flux density from rising to the saturation level. By using a permanent bias flux to oppose the flux generated by the DC component of the current, one would reduce the net DC component of flux in the core, making it possible to reduce the core size needed to prevent the total flux density (sum of DC and AC components) from rising to the saturation level. Alternatively, one could take advantage of the reduction of the net DC component of flux by increasing the allowable AC component of flux and the corresponding AC component of current

  2. Blur invariants constructed from arbitrary moments.

    Science.gov (United States)

    Kautsky, Jaroslav; Flusser, Jan

    2011-12-01

    This paper deals with moment invariants with respect to image blurring. It is mainly a reaction to the works of Zhang and Chen , recently published in these Transactions. We present a general method on how to construct blur invariants from arbitrary moments and show that it is no longer necessary to separately derive the invariants for each polynomial basis. We show how to discard dependent terms in blur invariants definition and discuss a proper implementation of the invariants in orthogonal bases using recurrent relations. An example for Legendre moments is given. © 2011 IEEE

  3. Making Knowledge Actionable: Three Key Translation Moments

    Directory of Open Access Journals (Sweden)

    John R. Austin

    2013-12-01

    Full Text Available Leaders regularly experience pressure to move innovation and change initiatives through their organizations. They face the challenge of transforming organizational changes and innovations from ideas into sustained behavior. In this commentary, I argue that successful implementation requires leaders to engage in a translation process that contains three key translation “moments”. The challenges presented by these translation moments are magnified by the difficulty leaders often have in shifting from one moment to the next. Techniques for handling each translation moment are discussed.

  4. Spontaneous breaking of supersymmetry

    Energy Technology Data Exchange (ETDEWEB)

    Zumino, B.

    1981-12-01

    There has been recently a revival of interest in supersymmetric gauge theories, stimulated by the hope that supersymmetry might help in clarifying some of the questions which remain unanswered in the so called Grand Unified Theories and in particular the gauge hierarchy problem. In a Grand Unified Theory one has two widely different mass scales: the unification mass M approx. = 10/sup 15/GeV at which the unification group (e.g. SU(5)) breaks down to SU(3) x SU(2) x U(1) and the mass ..mu.. approx. = 100 GeV at which SU(2) x U(1) is broken down to the U(1) of electromagnetism. There is at present no theoretical understanding of the extreme smallness of the ratio ..mu../M of these two numbers. This is the gauge hierarchy problem. This lecture attempts to review the various mechanisms for spontaneous supersymmetry breaking in gauge theories. Most of the discussions are concerned with the tree approximation, but what is presently known about radiative correction is also reviewed.

  5. Spontaneous intracranial hypotension

    International Nuclear Information System (INIS)

    Haritanti, A.; Karacostas, D.; Drevelengas, A.; Kanellopoulos, V.; Paraskevopoulou, E.; Lefkopoulos, A.; Economou, I.; Dimitriadis, A.S.

    2009-01-01

    Spontaneous intracranial hypotension (SIH) is an uncommon but increasingly recognized syndrome. Orthostatic headache with typical findings on magnetic resonance imaging (MRI) are the key to diagnosis. Delayed diagnosis of this condition may subject patients to unnecessary procedures and prolong morbidity. We describe six patients with SIH and outline the important clinical and neuroimaging findings. They were all relatively young, 20-54 years old, with clearly orthostatic headache, minimal neurological signs (only abducent nerve paresis in two) and diffuse pachymeningeal gadolinium enhancement on brain MRI, while two of them presented subdural hygromas. Spinal MRI was helpful in detecting a cervical cerebrospinal fluid leak in three patients and dilatation of the vertebral venous plexus with extradural fluid collection in another. Conservative management resulted in rapid resolution of symptoms in five patients (10 days-3 weeks) and in one who developed cerebral venous sinus thrombosis, the condition resolved in 2 months. However, this rapid clinical improvement was not accompanied by an analogous regression of the brain MR findings that persisted on a longer follow-up. Along with recent literature data, our patients further point out that SIH, to be correctly diagnosed, necessitates increased alertness by the attending physician, in the evaluation of headaches

  6. Spontaneous lateral temporal encephalocele.

    Science.gov (United States)

    Tuncbilek, Gokhan; Calis, Mert; Akalan, Nejat

    2013-01-01

    A spontaneous encephalocele is one that develops either because of embryological maldevelopment or from a poorly understood postnatal process that permits brain herniation to occur. We here report a rare case of lateral temporal encephalocele extending to the infratemporal fossa under the zygomatic arch. At birth, the infant was noted to have a large cystic mass in the right side of the face. After being operated on initially in another center in the newborn period, the patient was referred to our clinic with a diagnosis of temporal encephalocele. He was 6 months old at the time of admission. Computerized tomography scan and magnetic resonance imaging studies revealed a 8 × 9 cm fluid-filled, multiloculated cystic mass at the right infratemporal fossa. No intracranial pathology or connection is seen. The patient was operated on to reduce the distortion effect of the growing mass. The histopathological examination of the sac revealed well-differentiated mature glial tissue stained with glial fibrillary acid protein. This rare clinical presentation of encephaloceles should be taken into consideration during the evaluation of the lateral facial masses in the infancy period, and possible intracranial connection should be ruled out before surgery to avoid complications.

  7. Center for Gyrokinetic/MHD Hybrid Simulation of Energetic Particle Physics in Toroidal Plasmas (CSEPP). Final report

    International Nuclear Information System (INIS)

    Chen, Yang

    2012-01-01

    At Colorado University-Boulder the primary task is to extend our gyrokinetic Particle-in-Cell simulation of tokamak micro-turbulence and transport to the area of energetic particle physics. We have implemented a gyrokinetic ion/massless fluid electron hybrid model in the global δf-PIC code GEM, and benchmarked the code with analytic results on the thermal ion radiative damping rate of Toroidal Alfven Eigenmodes (TAE) and with mode frequency and spatial structure from eigenmode analysis. We also performed nonlinear simulations of both a single-n mode (n is the toroidal mode number) and multiple-n modes, and in the case of single-n, benchmarked the code on the saturation amplitude vs. particle collision rate with analytical theory. Most simulations use the f method for both ions species, but we have explored the full-f method for energetic particles in cases where the burst amplitude of the excited instabilities is large as to cause significant re-distribution or loss of the energetic particles. We used the hybrid model to study the stability of high-n TAEs in ITER. Our simulations show that the most unstable modes in ITER lie in the rage of 10 α (0) = 0.7% for the fully shaped ITER equilibrium. We also carried nonlinear simulations of the most unstable n = 15 mode and found that the saturation amplitude for the nominal ITER discharge is too low to cause large redistribution or loss of alpha particles. To include kinetic electron effects in the hybrid model we have studied a kinetic electron closure scheme for the fluid electron model. The most important element of the closure scheme is a complete Ohm's law for the parallel electric field E || , derived by combining the quasi-neutrality condition, the Ampere's equation and the v || moment of the gyrokinetic equations. A discretization method for the closure scheme is studied in detail for a three-dimensional shear-less slab plasma. It is found that for long-wavelength shear Alfven waves the kinetic closure scheme

  8. Bilateral spontaneous carotid artery dissection.

    Science.gov (United States)

    Townend, Bradley Scott; Traves, Laura; Crimmins, Denis

    2005-06-01

    Bilateral internal carotid artery dissections have been reported, but spontaneous bilateral dissections are rare. Internal carotid artery dissection can present with a spectrum of symptoms ranging from headache to completed stroke. Two cases of spontaneous bilateral carotid artery dissection are presented, one with headache and minimal symptoms and the other with a stroke syndrome. No cause could be found in either case, making the dissections completely spontaneous. Bilateral internal carotid artery dissection (ICAD) should be considered in young patients with unexplained head and neck pain with or without focal neurological symptoms and signs. The increasing availability of imaging would sustain the higher index of suspicion.

  9. Toroidal rotation braking with n = 1 magnetic perturbation field on JET

    DEFF Research Database (Denmark)

    Sun, Y; Liang, Y; Koslowski, H R

    2010-01-01

    A strong toroidal rotation braking has been observed in plasmas with application of an n = 1 magnetic perturbation field on the JET tokamak. Calculation results from the momentum transport analysis show that the torque induced by the n = 1 perturbation field has a global profile. The maximal value...

  10. Conceptual Design of a New Large Superconducting Toroid for IAXO, the New International AXion Observatory

    CERN Document Server

    Shilon, I.; Silva, H.; ten Kate, H.H.J.

    2013-01-01

    The International AXion Observatory (IAXO) will incorporate a new generation detector for axions, a hypothetical particle, which was postulated to solve one of the puzzles arising in the standard model of particle physics, namely the strong CP problem. The new IAXO experiment is aiming at achieving a sensitivity to the coupling between axions and photons of one order of magnitude beyond the limits of the current state-of-the-art detector, represented by the CERN Axion Solar Telescope (CAST). The IAXO detector relies on a high-magnetic field distributed over a very large volume to convert solar axions into x-ray photons. Utilizing the designs of the ATLAS barrel and end-cap toroids, a large superconducting toroidal magnet is currently being designed at CERN to provide the required magnetic field. The new toroid will be built up from eight, one meter wide and 20 m long, racetrack coils. The toroid is sized about 4 m in diameter and 22 m in length. It is designed to realize a peak magnetic field of 5.4 T with a ...

  11. Optimizing dc-resistance of a foil wounded toroidal inductor combining matlab and comsol

    DEFF Research Database (Denmark)

    Schneider, Henrik; Andersen, Thomas; Knott, Arnold

    2013-01-01

    An optimization routine is presented to optimize the shape of a foil winding of a toroid inductor in terms of the DC resistance. MATLAB was used to define the geometry of the foil winding and COMSOL was used to import the geometry and create a 3D finite element model. The initial parameters...

  12. Excitation adjustable system of toroidal field waveform for tokamak HL-1

    International Nuclear Information System (INIS)

    Ren Juqian; Yu Xianrong; Xie Yongzhong

    1989-11-01

    The closed-loop adjusting system of the toroidal field waveform is described. Technical measures have been taken to improve the stability of the system and the repetitiveness of wave adjustment. Meanwhile the wiring and technical characteristics of the system are discussed and the level of the system attained is compared with that of the original system

  13. Collisional boundary layer analysis for neoclassical toroidal plasma viscosity in tokamaks

    Czech Academy of Sciences Publication Activity Database

    Shaing, K.C.; Cahyna, Pavel; Bécoulet, M.; Park, J.-K.; Sabbagh, S.A.; Chu, M.S.

    2008-01-01

    Roč. 15, č. 8 (2008), 082506-1-7 ISSN 1070-664X Institutional research plan: CEZ:AV0Z20430508 Keywords : plasma boundary layers * plasma toroidal confinement * Tokamak devices Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.427, year: 2008 http://dx.doi.org/10.1063/1.2969434

  14. Internal Field of Homogeneously Magnetized Toroid Sensor for Proton Free Precession Magnetometer

    DEFF Research Database (Denmark)

    Primdahl, Fritz; Merayo, José M.G.; Brauer, Peter

    2005-01-01

    The shift of the NMR spectral line frequency in a proton free precession absolute scalar magnetometer using the omni-directional toroid container for a proton-rich liquid depends on the magnetic susceptibility of the liquid and on the direction of the external field relative to the axis of the to......The shift of the NMR spectral line frequency in a proton free precession absolute scalar magnetometer using the omni-directional toroid container for a proton-rich liquid depends on the magnetic susceptibility of the liquid and on the direction of the external field relative to the axis...... of the toroid. The theoretical shift is estimated for water by computing the additional magnetic field from the magnetization of the liquid and comparing it to the theoretical field in a spherical container. Along the axis the estimated average shift is -0.08 nT and perpendicular to the axis the shift is +0.......08 nT relative to that of a spherical sensor. The field inhomogeneity introduced by the toroid shape amounts to 0.32 nT over the volume of the sensor and is not expected to significantly affect the signal decay time, when considering the typical water line width of about 2.5 InT....

  15. On the fundamental mode of the optical resonator with toroidal mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Serednyakov, S.S.; Vinokurov, N.A. [Budker Institute of Nuclear Physics, Novosibirsk (Russian Federation)

    1995-12-31

    The fundamental mode of the optical resonator with the toroidal mirrors is investigated. The losses in such resonator with the on-axis holes are low in compare with the case of spherical mirrors. The use of this type of optical resonator is briefly discussed.

  16. The effect of toroidal plasma rotation on low-frequency reversed shear Alfven eigenmodes in tokamaks

    NARCIS (Netherlands)

    Haverkort, J. W.

    2012-01-01

    The influence of toroidal plasma rotation on the existence of reversed shear Alfven eigenmodes (RSAEs) near their minimum frequency is investigated analytically. An existence condition is derived showing that a radially decreasing kinetic energy density is unfavourable for the existence of RSAEs.

  17. Momentum transport studies in JET H-mode discharges with an enhanced toroidal field ripple

    NARCIS (Netherlands)

    de Vries, P. C.; Versloot, T. W.; Salmi, A.; Hua, M. D.; Howell, D. H.; Giroud, C.; Parail, V.; Saibene, G.; Tala, T.

    2010-01-01

    In this study, enhancement of the toroidal field (TF) ripple has been used as a tool in order to reveal the impact of the momentum pinch on the rotation profiles in H-mode JET discharges. The analysis showed that flatter rotation profiles were obtained in discharges with a high TF ripple, attributed

  18. Vortex-vortex interactions in toroidally trapped Bose-Einstein condensates

    OpenAIRE

    Schulte, T.; Santos, L.; Sanpera, A.; Lewenstein, M.

    2002-01-01

    We analyze the vortex dynamics and vortex-vortex interactions in Bose-Einstein condensates confined in toroidal traps. We show that this particular geometry strongly distorts the vortex dynamics. The numerically calculated vortex trajectories are well explained by an analytical calculation based on image method and conformal mapping. Finally, the dissipation effects are discussed.

  19. Elastic stability and vibration of toroidal magnets for fusion reactors. Final report

    International Nuclear Information System (INIS)

    Moon, F.C.; Swanson, C.

    1975-09-01

    The vibration and elastic stability of a set of discrete superconducting toroidal field magnets arranged to form a ''bumpy'' torus is examined. The mutual destabilizing magnetic forces between magnet pairs are calculated using a numerical differential inductance technique. It is shown that the mutual attractive magnetic forces can produce elastic buckling of the entire toroidal set. The vibration modes of the set are also found as functions of the coil current. The response of the set of magnets to an earthquake type motion of the toroidal base is calculated. The calculations have been incorporated in a computer code which accompanies the report. Measurements are made of the lateral stiffness of a flexible, planar, superconducting coil between two rigid coils in series. These tests show a dramatic decrease in the natural bending frequency with subsequent elastic instability or ''buckling'' at a critical value of the current in the coils. These observations support a magnetoelastic analysis which shows that proposed designs, of toroidal field coils for Tokamak fusion reactors, have insufficient lateral support for mechanical stability of the magnets

  20. STRESS DISTRIBUTION IN A TOROIDAL RING SECTOR SUBJECTED TO BENDING AND TWISTING

    Directory of Open Access Journals (Sweden)

    Yaşar PALA

    1997-03-01

    Full Text Available In this study, stress analysis in a toroidal ring sector with an elliptical cross section composed of two confocal ellipses is considered. Göhner's method is used in the analysis. The results obtained for the case of pure torsion is superposed with those corresponding to pure bending in order to reach to the case of combined loading.

  1. Los Alamos compact toroid, fast-liner, and high-density Z-pinch programs

    Energy Technology Data Exchange (ETDEWEB)

    Linford, R.K.; Sherwood, A.R.; Hammel, J.E.

    1981-03-01

    The Compact Toroid (CT) and High Density Z-Pinch (HDZP) are two of the plasma configurations presently being studied at Los Alamos. The purpose of these two programs, plus the recently terminated (May 1979) Fast Liner (FL) program, is summarized in this section along with a brief description of the experimental facilities. The remaining sections summarize the recent results and the experimental status.

  2. Comment on radial structure of high-mode-number toroidal modes in general equilibrium profiles

    International Nuclear Information System (INIS)

    Zhang, Y.Z.; Mahajan, S.M.

    1995-01-01

    The comment express the disagreement of the authors with the results claimed in the paper 'Radial Structure of High-Mode-Number Toroidal Modes in General Equilibrium Profiles' by J-Y.Kim and M.Wakatani, Phys.Rev.Lett.73, 2200 (1994) concerning the 2D structure (ballooning theory) of the modes in an axisymmetric torus. 5 refs

  3. Investigation of a Hybrid Winding Concept for Toroidal Inductors using 3D Finite Element Modeling

    DEFF Research Database (Denmark)

    Schneider, Henrik; Andersen, Thomas; Mønster, Jakob Døllner

    2013-01-01

    This paper investigates a hybrid winding concept for a toroidal inductor by simulating the winding resistance as a function of frequency. The problem of predicting the resistance of a non-uniform and complex winding shape is solved using 3D Finite Element Modeling. A prototype is built and tested...

  4. An analysis of plasma ion toroidal rotation during large amplitude MHD activity in JET

    International Nuclear Information System (INIS)

    Snipes, J.A.; Esch, H.P.L. de; Lazzaro, E.; Stork, D.; Hellermann, M. von; Galvao, R.; Hender, T.C.; Zasche, D.

    1989-01-01

    A detailed study of plasma ion toroidal rotation in JET during large amplitude MHD activity has revealed a strong viscous force that couples plasma ions to MHD modes. Depending on the MHD modes present, this force can couple across all of the plasma cross section, across only the central region, roughly within the q=1 surface, or across only the outer region outside the q=1.5 surface. The force acts to flatten the ion toroidal rotation frequency profile, measured by the JET active charge exchange spectroscopy diagnostic, across the coupled region of plasma. The frequency of rotation in this region agrees with the MHD oscillation frequency measured by magnetic pick-up coils at the wall. The strength of the force between the ions and modes becomes evident during high power NBI when the mode locks and drags the ion toroidal rotation frequency to zero, within the errors of the measurements. The present theories of plasma rotation either ignore MHD effects entirely, consider only moderate n toroidal field ripple, or low n ripple effects. (author) 7 refs., 3 figs

  5. Effect of continuous eigenvalue spectrum on plasma transport in toroidal systems

    International Nuclear Information System (INIS)

    Yamagishi, Tomejiro

    1993-03-01

    The effect of the continuous eigenvalue of the Vlasov equation on the cross field ion thermal flux is investigated. The continuum contribution due to the toroidal drift resonance is found to play an important role in ion transport particularly near the edge, which may apply to the interpretation of the sharp increase of ion heat conductivity near the periphery observed in large tokamaks. (author)

  6. Effects of Toroidal Magnetic Fields on the Thermal Instability of Thin ...

    Indian Academy of Sciences (India)

    Effects of Toroidal Magnetic Fields on the Thermal Instability of Thin Accretion Disks. Sheng-Ming Zheng1, Feng Yuan2, Wei-Min Gu1,∗. & Ju-Fu Lu1. 1Department of Physics and Institute of Theoretical Physics and Astrophysics,. Xiamen University, Xiamen, Fujian 361005, China. 2Key Laboratory for Research in Galaxies ...

  7. Some characteristics of the superconducting magnetic system of toroidal spectrometer STORS

    International Nuclear Information System (INIS)

    Andreev, S.V.; Vorozhtsov, S.B.; Kakurin, S.I.

    1993-01-01

    A superconducting toroidal spectrometer (STORS) has been suggested to provide precision measurements of structure functions in muon beams. In this paper we present the calculation of the magnet induction and forces influencing the elements of the magnet, requirements to the reliability and rigidity of the carrying elements of the magnet construction. (author.) 14 refs.; 50 figs.; 4 tabs

  8. Performance assessment and optimization of the ITER toroidal field coil joints

    NARCIS (Netherlands)

    Rolando, G.; Foussat, A.; Knaster, J.; Ilyin, Y.; Nijhuis, Arend

    2013-01-01

    The ITER toroidal field (TF) system features eighteen coils that will provide the magnetic field necessary to confine the plasma. Each winding pack is composed of seven double pancakes (DP) connected through praying hands joints. Shaking hands joints are used to interface the terminals of the

  9. Aurora T: a Monte Carlo code for transportation of neutral atoms in a toroidal plasma

    International Nuclear Information System (INIS)

    Bignami, A.; Chiorrini, R.

    1982-01-01

    This paper contains a short description of Aurora code. This code have been developed at Princeton with Monte Carlo method for calculating neutral gas in cylindrical plasma. In this work subroutines such one can take in account toroidal geometry are developed

  10. On recursive relations and moment problems

    International Nuclear Information System (INIS)

    El Wahbi, B.; Rachidi, M.; Zerouali, E.H.

    2001-09-01

    We investigate in this paper the link between the moment problem for sequences, the associated Jacobi matrices and the Pade approximants of the associated analytic functions. We generalize some classical results by providing simple proofs that use functional calculus. (author)

  11. Moments of inertia in a semiclassical approach

    International Nuclear Information System (INIS)

    Benchein, K.

    1993-01-01

    Semiclassical calculations have been performed for 31 nuclei. As a result of preliminary non-fully self-consistent calculations, the moments of inertia in investigated nuclei abd spin degrees of freedom are found

  12. Moments of the very high multiplicity distributions

    International Nuclear Information System (INIS)

    Nechitailo, V.A.

    2004-01-01

    In experiment, the multiplicity distributions of inelastic processes are truncated due to finite energy, insufficient statistics, or special choice of events. It is shown that the moments of such truncated multiplicity distributions possess some typical features. In particular, the oscillations of cumulant moments at high ranks and their negative values at the second rank can be considered as ones most indicative of the specifics of these distributions. They allow one to distinguish between distributions of different type

  13. Affine Moment Invariants Generated by Graph Method

    Czech Academy of Sciences Publication Activity Database

    Suk, Tomáš; Flusser, Jan

    2011-01-01

    Roč. 44, č. 9 (2011), 2047 – 2056 ISSN 0031-3203 R&D Projects: GA ČR(CZ) GA102/08/1593 Institutional research plan: CEZ:AV0Z10750506 Keywords : Image moments * Object recognition * Affine transformation * Affine moment invariants * Pseudoinvariants * Graph representation * Irreducibility * Independence Subject RIV: IN - Informatics, Computer Science Impact factor: 2.292, year: 2011 http://library.utia.cas.cz/separaty/2011/ZOI/suk-0359752.pdf

  14. Moment approach to tandem mirror radial transport

    International Nuclear Information System (INIS)

    Siebert, K.D.; Callen, J.D.

    1986-02-01

    A moment approach is proposed for the study of tandem mirror radial transport in the resonant plateau regime. The salient features of the method are described with reference to axisymmetric tokamak transport theory. In particular, the importance of momentum conservation to the establishment of the azimuthal variations in the electrostatic potential is demonstrated. Also, an ad hoc drift kinetic equation is solved to determine parallel viscosity coefficients which are required to close the moment system

  15. Toroidally asymmetric particle transport caused by phase-locking of MHD modes in RFX-mod

    International Nuclear Information System (INIS)

    Lorenzini, R.; Terranova, D.; Auriemma, F.; Cavazzana, R.; Innocente, P.; Martini, S.; Serianni, G.; Zuin, M.

    2007-01-01

    The particle and energy transport in reversed field pinch experiments is affected by the locking in phase of the tearing modes, also dubbed dynamo modes, that sustain the magnetic configuration. In standard RFP pulses many m = 1 and m = 0 resonant modes have a relatively large amplitude (a spectrum dubbed MH for multiple helicity). The locking in phase of m = 1 tearing modes produces a helical deformation (locked mode (LM)) of the magnetic surfaces in a region of approximately 40 toroidal degrees. The region of the LM is characterized by a strong plasma-wall interaction and by high losses of energy and particles that account for a significant fraction of the input power and of the total particle outflux. The locking in phase of m = 0 modes modifies the plasma radius, shrinking and enlarging the plasma cross section in two wide toroidal regions of about 100 0 . The purpose of this paper is to investigate to what extent the locking in phase of m = 0 modes introduces toroidal asymmetries in the transport properties of the plasma. This study has been carried out investigating the shape of the density profile in the RFX-mod experiment. The analyses show that the profile exhibits a dependence on the toroidal angle, which is related to the deformation of the plasma column due to the locking in phase of m = 0 modes: the least steep density gradients at the edge are found in the region where the plasma column is shrunk, entailing that in this region the particle transport is enhanced. An analogous asymmetry also characterizes the density and magnetic fluctuations at the edge, which are enhanced in the same toroidal region where the particle transport also is enhanced. This result can be considered the first experimental evidence of an instability localized where the plasma column is shrunk

  16. Structure and damping of toroidal drift waves (and their implications for anomalous transport)

    International Nuclear Information System (INIS)

    Taylor, J.B.; Connor, J.; Wilson, H.R.

    1993-05-01

    The conventional theory of high-n toroidal drift waves, based on the ballooning representation, indicates that shear-damping is generally reduced in a torus compared to its plane-slab value. It therefore describes the most unstable class of toroidal drift waves. However, modes of this type occur only i f the diamagnetic frequency ω*(r) has a maximum in r, and they affect only a small fraction, Ο(1/n l/2 ), of the plasma radius around this maximum. Consequently they may produce little anomalous transport. In the present work we show that, within the ballooning description, there is another class of toroidal drift waves with very different properties to the conventional ones. The new modes have greater shear-damping (closer to that in a plane-slab) than the conventional ones and so have a higher instability threshold. However, they occur for any plasma profile and at all radii, and they have larger radial extent. Consequently they may produce much greater anomalous transport than the possibly benign conventional modes. This suggests a picture of anomalous transport in which the plasma profile is determined by marginal stability, but marginal to the new class of modes not to the conventional ones. This might explain why marginally stable profiles calculated for drift waves with plane-slab damping sometimes agree well with the profiles in toroidal experiments. It is also consistent with the fact that experimental profiles may exceed conventional toroidal instability thresholds. The new modes may also be related to the tong radial structures which appear in some plasma simulations and in experiments

  17. Suppression of m = 0 in a RFP by toroidal field coils

    International Nuclear Information System (INIS)

    Alexander, D.; Robertson, S.

    1993-01-01

    The Reversatron RFP is normally operated with the toroidal field coils connected in series. The time-integrated voltage applied to the circuit determines the sum of the fluxes linking each turn but not the flux within each turn. Each winding may have a different flux determined by the external drive and by currents within the plasma. A parallel connection of the field coils results in the flux within each coil being determined by the volt-seconds applied to the windings; thus the toroidal flux is the same within each coil. This configuration suppresses any toroidal variation in the toroidal flux and effectively reduces the level of the m = 0 component of the radial field. The m = 0 fluctuations are expected to arise due to nonlinear coupling of the m = 1 modes. A parallel connection of field coils is impractical due to the low impedance required for driving the coils. The authors have tested the effect of parallel connected coils by adding an auxiliary set of 36 coils. These are connected in parallel but are not connected to any supply. The toroidal flux is generated by the series-connected coils which generate voltage but not current in the parallel-connected coils. With the auxiliary coils, the discharge duration is increased from 500 to 550 μsec, the plasma current is increased from 50 kA to 60 kA, F is more negative, Θ is larger, and there is less shot-to-shot variation in the discharges. The m = 0 fluctuations measured by 43 surface coils are, however, only slightly reduced

  18. Spontaneous intraorbital hematoma: case report

    Directory of Open Access Journals (Sweden)

    Vinodan Paramanathan

    2010-12-01

    Full Text Available Vinodan Paramanathan, Ardalan ZolnourianQueen's Hospital NHS Foundation Trust, Burton on Trent, Staffordshire DE13 0RB, UKAbstract: Spontaneous intraorbital hematoma is an uncommon clinical entity seen in ophthalmology practice. It is poorly represented in the literature. Current evidence attributes it to orbital trauma, neoplasm, vascular malformations, acute sinusitis, and systemic abnormalities. A 65-year-old female presented with spontaneous intraorbital hematoma manifesting as severe ocular pains, eyelid edema, proptosis, and diplopia, without a history of trauma. Computer tomography demonstrated a fairly well defined extraconal lesion with opacification of the paranasal sinuses. The principal differential based on all findings was that of a spreading sinus infection and an extraconal tumor. An unprecedented finding of a spontaneous orbital hematoma was discovered when the patient was taken to theater. We discuss the rarity of this condition and its management.Keywords: hemorrhage, ophthalmology, spontaneous, intra-orbital, hematoma

  19. Spontaneous ischaemic stroke in dogs

    DEFF Research Database (Denmark)

    Gredal, Hanne Birgit; Skerritt, G. C.; Gideon, P.

    2013-01-01

    Translation of experimental stroke research into the clinical setting is often unsuccessful. Novel approaches are therefore desirable. As humans, pet dogs suffer from spontaneous ischaemic stroke and may hence offer new ways of studying genuine stroke injury mechanisms.......Translation of experimental stroke research into the clinical setting is often unsuccessful. Novel approaches are therefore desirable. As humans, pet dogs suffer from spontaneous ischaemic stroke and may hence offer new ways of studying genuine stroke injury mechanisms....

  20. Spontaneity and international marketing performance

    OpenAIRE

    Souchon, Anne L.; Hughes, Paul; Farrell, Andrew M.; Nemkova, Ekaterina; Oliveira, Joao S.

    2016-01-01

    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link. Purpose – The purpose of this paper is to ascertain how today’s international marketers can perform better on the global scene by harnessing spontaneity. Design/methodology/approach – The authors draw on contingency theory to develop a model of the spontaneity – international marketing performance relationship, and identify three potential m...

  1. Performance Evaluation of Moment Connections of Moment Resisting Frames Against Progressive Collapse

    Directory of Open Access Journals (Sweden)

    M. Mahmoudi

    2017-02-01

    Full Text Available When a primary structural element fails due to sudden load such as explosion, the building undergoes progressive collapse. The method for design of moment connections during progressive collapse is different to seismic design of moment connections. Because in this case, the axial force on the connections makes it behave differently. The purpose of this paper is to evaluate the performance of a variety of moment connections in preventing progressive collapse in steel moment frames. To achieve this goal, three prequalified moment connections (BSEEP, BFP and WUP-W were designed according seismic codes. These moment connections were analyzed numerically using ABAQUS software for progressive collapse. The results show that the BFP connection (bolted flange plate has capacity much more than other connections because of the use of plates at the junction of beam-column.

  2. Effect of torsion moment on failure bending moment for circumferentially cracked pipe

    International Nuclear Information System (INIS)

    Li, Yinsheng; Hasegawa, Kunio; Ida, Wataru; Hoang, Phuong H.; Bezensek, Bostjan

    2010-01-01

    When a crack is detected in a stainless steel pipe during in-service inspection, the limit load criterion given in the codes such as JSME Rules on Fitness-for-Service for Nuclear Power Plants or ASME Boiler and Pressure Vessel Code Section XI can be applied to evaluate the integrity of the pipe. However, in the current codes, the limit load criterion is only provided considering pressure and bending moment. The torsion moment is not considered, although torsion moment does exist in the nuclear power piping system. In this paper, finite element analyses are carried out for stainless steel pipe containing a circumferential surface crack under the combination of bending moment and torsion moment, considering different pipe dimensions and flaw sizes. Based upon the analysis results, a plastic collapse estimation method is proposed considering the existence of the torsion moment and its magnitude, and this method make it possible to evaluate the integrity of the pipe for general loading conditions. (author)

  3. Baroclinic Instability in the Solar Tachocline for Continuous Vertical Profiles of Rotation, Effective Gravity, and Toroidal Field

    Energy Technology Data Exchange (ETDEWEB)

    Gilman, Peter A., E-mail: gilman@ucar.edu [High Altitude Observatory, National Center for Atmospheric Research, 3080 Center Green, Boulder, CO 80307-3000 (United States)

    2017-06-20

    We present results from an MHD model for baroclinic instability in the solar tachocline that includes rotation, effective gravity, and toroidal field that vary continuously with height. We solve the perturbation equations using a shooting method. Without toroidal fields but with an effective gravity declining linearly from a maximum at the bottom to much smaller values at the top, we find instability at all latitudes except at the poles, at the equator, and where the vertical rotation gradient vanishes (32.°3) for longitude wavenumbers m from 1 to >10. High latitudes are much more unstable than low latitudes, but both have e -folding times that are much shorter than a sunspot cycle. The higher the m and the steeper the decline in effective gravity, the closer the unstable mode peak to the top boundary, where the energy available to drive instability is greatest. The effect of the toroidal field is always stabilizing, shrinking the latitude ranges of instability as the toroidal field is increased. The larger the toroidal field, the smaller the longitudinal wavenumber of the most unstable disturbance. All latitudes become stable for a toroidal field exceeding about 4 kG. The results imply that baroclinic instability should occur in the tachocline at latitudes where the toroidal field is weak or is changing sign, but not where the field is strong.

  4. Predictions of toroidal rotation and torque sources arising in non-axisymmetric perturbed magnetic fields in tokamaks

    Science.gov (United States)

    Honda, M.; Satake, S.; Suzuki, Y.; Shinohara, K.; Yoshida, M.; Narita, E.; Nakata, M.; Aiba, N.; Shiraishi, J.; Hayashi, N.; Matsunaga, G.; Matsuyama, A.; Ide, S.

    2017-11-01

    Capabilities of the integrated framework consisting of TOPICS, OFMC, VMEC and FORTEC-3D, have been extended to calculate toroidal rotation in fully non-axisymmetric perturbed magnetic fields for demonstrating operation scenarios in actual tokamak geometry and conditions. The toroidally localized perturbed fields due to the test blanket modules and the tangential neutral beam ports in ITER augment the neoclassical toroidal viscosity (NTV) substantially, while do not significantly influence losses of beam ions and alpha particles in an ITER L-mode discharge. The NTV takes up a large portion of total torque in ITER and fairly decelerates toroidal rotation, but the change in toroidal rotation may have limited effectiveness against turbulent heat transport. The error field correction coils installed in JT-60SA can externally apply the perturbed fields, which may alter the NTV and the resultant toroidal rotation profiles. However, the non-resonant n=18 components of the magnetic fields arising from the toroidal field ripple mainly contribute to the NTV, regardless of the presence of the applied field by the coil current of 10 kA , where n is the toroidal mode number. The theoretical model of the intrinsic torque due to the fluctuation-induced residual stress is calibrated by the JT-60U data. For five JT-60U discharges, the sign of the calibration factor conformed to the gyrokinetic linear stability analysis and a range of the amplitude thereof was revealed. This semi-empirical approach opens up access to an attempt on predicting toroidal rotation in H-mode plasmas.

  5. Constraints on the scale of toroidal-fusion experiments with application to the design of a helical-axis stellarator

    International Nuclear Information System (INIS)

    Noterdaeme, J.M.

    1983-05-01

    Applying the constraints to the design of a helical axis stellarator we find a limit on the combination of toroidal field, current density and major radius. Another major constraint for this concept is the ability to obtain the plasma physics parameters dictated by similarity considerations. This depends on the heating method used. A minimum scale experiment with 2 periods and no linkage of the toroidal and poloidal coils, would have a major radius of 1.2m, a toroidal field of 3.5T and 2MW of ECRH power (for β = 1% nu 2 = 10)

  6. Spontaneous emission of an atom in the presence of nanobodies

    International Nuclear Information System (INIS)

    Klimov, Vasilii V; Ducloy, M; Letokhov, V S

    2001-01-01

    The effect of nanobodies, i.e., the bodies whose size is small compared to the emission wavelength, on spontaneous emission of an atom located near them is considered. The results of calculations performed within the framework of quantum and classical electrodynamics are presented both in analytic and graphical forms and can be readily used for planning experiments and analysis of experimental data. It is shown that nanobodies can be used to control efficiently the rate of spontaneous transitions. Thus, an excited atom located near a nanocylinder or a nanospheroid pole, whose transition dipole moment is directed normally to the nanobody surface, can decay with the rate that is tens and hundreds times higher than the decay rate in a free space. In the case of some (negative) dielectric constants, the decay rate can increase by a factor of 10 5 -10 6 and more. On the other hand, the decay of an excited atom whose transition dipole moment is directed tangentially to the nanobody surface substantially slows down. The probability of nonradiative decay of the excited state is shown to increase substantially in the presence of na-nobodies possessing losses. (review)

  7. Electric multipole moments, topological multipole moment pumping, and chiral hinge states in crystalline insulators

    Science.gov (United States)

    Benalcazar, Wladimir A.; Bernevig, B. Andrei; Hughes, Taylor L.

    2017-12-01

    We extend the theory of dipole moments in crystalline insulators to higher multipole moments. As first formulated in Benalcazar et al. [Science 357, 61 (2017), 10.1126/science.aah6442], we show that bulk quadrupole and octupole moments can be realized in crystalline insulators. In this paper, we expand in great detail the theory presented previously [Benalcazar et al., Science 357, 61 (2017), 10.1126/science.aah6442] and extend it to cover associated topological pumping phenomena, and a class of three-dimensional (3D) insulator with chiral hinge states. We start by deriving the boundary properties of continuous classical dielectrics hosting only bulk dipole, quadrupole, or octupole moments. In quantum mechanical crystalline insulators, these higher multipole bulk moments manifest themselves by the presence of boundary-localized moments of lower dimension, in exact correspondence with the electromagnetic theory of classical continuous dielectrics. In the presence of certain symmetries, these moments are quantized, and their boundary signatures are fractionalized. These multipole moments then correspond to new symmetry-protected topological phases. The topological structure of these phases is described by "nested" Wilson loops, which we define. These Wilson loops reflect the bulk-boundary correspondence in a way that makes evident a hierarchical classification of the multipole moments. Just as a varying dipole generates charge pumping, a varying quadrupole generates dipole pumping, and a varying octupole generates quadrupole pumping. For nontrivial adiabatic cycles, the transport of these moments is quantized. An analysis of these interconnected phenomena leads to the conclusion that a new kind of Chern-type insulator exists, which has chiral, hinge-localized modes in 3D. We provide the minimal models for the quantized multipole moments, the nontrivial pumping processes, and the hinge Chern insulator, and describe the topological invariants that protect them.

  8. A case of spontaneous ventriculocisternostomy

    International Nuclear Information System (INIS)

    Yamane, Kanji; Yoshimoto, Hisanori; Harada, Kiyoshi; Uozumi, Tohru; Kuwabara, Satoshi.

    1983-01-01

    The authors experienced a case of spontaneous ventriculocisternostomy diagnosed by CT scan with metrizamide and Conray. Patient was 23-year-old male who had been in good health until one month before admission, when he began to have headache and tinnitus. He noticed bilateral visual acuity was decreased about one week before admission and vomiting appeared two days before admission. He was admitted to our hospital because of bilateral papilledema and remarkable hydrocephalus diagnosed by CT scan. On admission, no abnormal neurological signs except for bilateral papilledema were noted. Immediately, right ventricular drainage was performed. Pressure of the ventricle was over 300mmH 2 O and CSF was clear. PVG and PEG disclosed an another cavity behind the third ventricle, which was communicated with the third ventricle, and occlusion of aqueduct of Sylvius. Metrizamide CT scan and Conray CT scan showed a communication between this cavity and quadrigeminal and supracerebellar cisterns. On these neuroradiological findings, the diagnosis of obstructive hydrocephalus due to benign aqueduct stenosis accompanied with spontaneous ventriculocisternostomy was obtained. Spontaneous ventriculocisternostomy was noticed to produce arrest of hydrocephalus, but with our case, spontaneous regression of such symptoms did not appeared. By surgical ventriculocisternostomy (method by Torkildsen, Dandy, or Scarff), arrest of hydrocephalus was seen in about 50 to 70 per cent, which was the same results as those of spontaneous ventriculocisternostomy. It is concluded that VP shunt or VA shunt is thought to be better treatment of obstructive hydrocephalus than the various kinds of surgical ventriculocisternostomy. (J.P.N.)

  9. Optical antenna enhanced spontaneous emission.

    Science.gov (United States)

    Eggleston, Michael S; Messer, Kevin; Zhang, Liming; Yablonovitch, Eli; Wu, Ming C

    2015-02-10

    Atoms and molecules are too small to act as efficient antennas for their own emission wavelengths. By providing an external optical antenna, the balance can be shifted; spontaneous emission could become faster than stimulated emission, which is handicapped by practically achievable pump intensities. In our experiments, InGaAsP nanorods emitting at ∼ 200 THz optical frequency show a spontaneous emission intensity enhancement of 35 × corresponding to a spontaneous emission rate speedup ∼ 115 ×, for antenna gap spacing, d = 40 nm. Classical antenna theory predicts ∼ 2,500 × spontaneous emission speedup at d ∼ 10 nm, proportional to 1/d(2). Unfortunately, at d antenna efficiency drops below 50%, owing to optical spreading resistance, exacerbated by the anomalous skin effect (electron surface collisions). Quantum dipole oscillations in the emitter excited state produce an optical ac equivalent circuit current, I(o) = qω|x(o)|/d, feeding the antenna-enhanced spontaneous emission, where q|x(o)| is the dipole matrix element. Despite the quantum-mechanical origin of the drive current, antenna theory makes no reference to the Purcell effect nor to local density of states models. Moreover, plasmonic effects are minor at 200 THz, producing only a small shift of antenna resonance frequency.

  10. Dipole moment dark matter at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Barger, Vernon [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Keung, Wai-Yee [Department of Physics, University of Illinois at Chicago, IL 60607 (United States); Marfatia, Danny, E-mail: marfatia@ku.edu [Department of Physics and Astronomy, University of Kansas, Lawrence, KS 66045 (United States); Tseng, Po-Yan [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Department of Physics, National Tsing Hua University, Hsinchu 300, Taiwan (China)

    2012-10-22

    Monojet and monophoton final states with large missing transverse energy (E/{sub T}) are important for dark matter (DM) searches at colliders. We present analytic expressions for the differential cross sections for the parton-level processes, qq{sup Macron }(qg){yields}g(q){chi}{chi}{sup Macron} and qq{sup Macron }{yields}{gamma}{chi}{chi}{sup Macron }, for a neutral DM particle with a magnetic dipole moment (MDM) or an electric dipole moment (EDM). We collectively call such DM candidates dipole moment dark matter (DMDM). We also provide monojet cross sections for scalar, vector and axial-vector interactions. We then use ATLAS/CMS monojet+E/{sub T} data and CMS monophoton+E/{sub T} data to constrain DMDM. We find that 7 TeV LHC bounds on the MDM DM-proton scattering cross section are about six orders of magnitude weaker than on the conventional spin-independent cross section.

  11. The moments of inertia of mars

    International Nuclear Information System (INIS)

    Bills, B.G.

    1989-01-01

    The mean moment of inertia of Mars is, at present, very poorly constrained. The generally accepted value of 0.365 MR 2 is obtained by assuming that the observed second degree gravity field can be decomposed into a hydrostatic oblate spheroid and a nonhydrostatic prolate spheroid with an equatorial axis of symmetry. An alternative decomposition is advocated in the present analysis. If the nonhydrostatic component is a maximally triaxial ellipsoid (intermediate moment midway between greatest and least) the hydrostatic component is consistent with a mean moment of 0.345 MR 2 . The plausibility of this decomposition is supported by statistical arguments and comparison with the Earth, Moon and Venus. If confirmed, this new value would have significant implications for the inferred composition and climatic history of Mars. The Mars Observer mission may help resolve this issue

  12. The anomalous magnetic moment of the muon

    CERN Document Server

    Jegerlehner, Friedrich

    2017-01-01

    This research monograph covers extensively the theory of the muon anomalous magnetic moment and provides estimates of the theoretical uncertainties. The muon anomalous magnetic moment is one of the most precisely measured quantities in elementary particle physics and provides one of the most stringent tests of relativistic quantum field theory as a fundamental theoretical framework. It allows for an extremely precise check of the standard model of elementary particles and of its limitations. This book reviews the present state of knowledge of the anomalous magnetic moment a=(g-2)/2 of the muon. Recent experiments at the Brookhaven National Laboratory now reach the unbelievable precision of 0.5 parts per million, improving the accuracy of previous g-2 experiments at CERN by a factor of 14. In addition, quantum electrodynamics and electroweak and hadronic effects are reviewed. Since non-perturbative hadronic effects play a key role for the precision test, their evaluation is described in detail. Perspectives fo...

  13. A corrector for spacecraft calculated electron moments

    Directory of Open Access Journals (Sweden)

    J. Geach

    2005-03-01

    Full Text Available We present the application of a numerical method to correct electron moments calculated on-board spacecraft from the effects of potential broadening and energy range truncation. Assuming a shape for the natural distribution of the ambient plasma and employing the scalar approximation, the on-board moments can be represented as non-linear integral functions of the underlying distribution. We have implemented an algorithm which inverts this system successfully over a wide range of parameters for an assumed underlying drifting Maxwellian distribution. The outputs of the solver are the corrected electron plasma temperature Te, density Ne and velocity vector Ve. We also make an estimation of the temperature anisotropy A of the distribution. We present corrected moment data from Cluster's PEACE experiment for a range of plasma environments and make comparisons with electron and ion data from other Cluster instruments, as well as the equivalent ground-based calculations using full 3-D distribution PEACE telemetry.

  14. Baryon magnetic moments: Symmetries and relations

    Energy Technology Data Exchange (ETDEWEB)

    Parreno, Assumpta [University of Barcelona; Savage, Martin [Univ. of Washington, Seattle, WA (United States); Tiburzi, Brian [City College of New York, NY (United States); City Univ. (CUNY), NY (United States); Wilhelm, Jonas [Justus-Liebig-Universitat Giessen, Giessen, Germany; Univ. of Washington, Seattle, WA (United States); Chang, Emmanuel [Univ. of Washington, Seattle, WA (United States); Detmold, William [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Orginos, Kostas [College of William and Mary, Williamsburg, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2018-04-01

    Magnetic moments of the octet baryons are computed using lattice QCD in background magnetic fields, including the first treatment of the magnetically coupled Σ0- Λ system. Although the computations are performed for relatively large values of the up and down quark masses, we gain new insight into the symmetries and relations between magnetic moments by working at a three-flavor mass-symmetric point. While the spinflavor symmetry in the large Nc limit of QCD is shared by the naïve constituent quark model, we find instances where quark model predictions are considerably favored over those emerging in the large Nc limit. We suggest further calculations that would shed light on the curious patterns of baryon magnetic moments.

  15. Nuclear moments of nuclei near sphericity

    International Nuclear Information System (INIS)

    El Hajjaji, O.

    1987-05-01

    Magnetic and electric hyperfine interactions are studied by means of low temperature nuclear orientation. The magnetic moment of the 149 Gd isotope and that of 151 Gd are determined. The values follow the same trend as literature values of neighbouring nuclei. The calculated moments of the 7/2 - states using the Mottelson-Nilsson model without configuration mixing are nearly independent of deformation. Thus we assign the decrease of the magnetic moment versus neutron number to many particle coupling in the f shell. The Moessbauer effect detection of nuclear orientation is discussed. Two series of experiences are performed with different finalities. In the first one we determined the electric quadrupole moments of 125m Te and 129 Te. The quadrupole moments confirm the nearly spherical shape of these nuclei. In the second series we describe the Moessbauer effect of the radiation emitted by the daigleter nucleus of 125 I, implanted in two semiconductor matrices, locally oriented at low temperature by the electric field gradient of impurity-vacancy coupling. Despite the difficulty of the cooling down of Te nuclei to lattice temperature, we have shown the existence of the electric field gradient of implanted I into Si and α-Sn and determined their signs. The level mixing resonance is applied on oriented nuclei technique to determine the weak prolate deformation of silver nuclei. Studying the Δm = 3 resonance of 107 Ag m , we etablished the quadrupole moment of this state, which is in good agreement with the theoretical estimations of Moeller and Nix [fr

  16. Scale invariants from Gaussian-Hermite moments

    Czech Academy of Sciences Publication Activity Database

    Yang, B.; Kostková, Jitka; Flusser, Jan; Suk, Tomáš

    2017-01-01

    Roč. 132, č. 1 (2017), s. 77-84 ISSN 0165-1684 R&D Projects: GA ČR GA15-16928S Institutional support: RVO:67985556 Keywords : Scale invariants * Gaussian–Hermite moments * Variable modulation * Normalization * Zernike moments Subject RIV: JD - Computer Applications, Robotics OBOR OECD: Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8) Impact factor: 3.110, year: 2016 http://library.utia.cas.cz/separaty/2016/ZOI/flusser-0466031.pdf

  17. Practical method for balancing airplane moments

    Science.gov (United States)

    Hamburger, H

    1924-01-01

    The present contribution is the sequel to a paper written by Messrs. R. Fuchs, L. Hopf, and H. Hamburger, and proposes to show that the methods therein contained can be practically utilized in computations. Furthermore, the calculations leading up to the diagram of moments for three airplanes, whose performance in war service gave reason for complaint, are analyzed. Finally, it is shown what conclusions can be drawn from the diagram of moments with regard to the defects in these planes and what steps may be taken to remedy them.

  18. Nuclear moments of inertia at high spin

    International Nuclear Information System (INIS)

    Deleplanque, M.A.

    1982-10-01

    The competition between collective motion and alignment at high spin can be evaluated by measuring two complementary dynamic moments of inertia. The first, I band, measured in γ-γ correlation experiments, relates to the collective properties of the nucleus. A new moment of inertia I/sub eff/ is defined here, which contains both collective and alignment effects. Both of these can be measured in continuum γ-ray spectra of rotational nuclei up to high frequencies. The evolution of γ-ray spectra for Er nuclei from mass 160 to 154 shows that shell effects can directly be observed in the spectra of the lighter nuclei

  19. Macroscopic quantum tunneling of the magnetic moment

    Science.gov (United States)

    Tejada, J.; Hernandez, J. M.; del Barco, E.

    1999-05-01

    In this paper we review the work done on magnetic relaxation during the last 10 years on both single-domain particles and magnetic molecules and its contribution to the discovery of quantum tunneling of the magnetic moment (Chudnovsky and Tejada, Macroscopic Quantum tunneling of the Magnetic moment, Cambridge University press, Cambridge, 1998). We present first the theoretical expressions and their connection to quantum relaxation and secondly, we show and discuss the experimental results. Finally, we discuss very recent hysteresis data on Mn 12Ac molecules at extremely large sweeping rate for the external magnetic field which suggest the existence of quantum spin—phonon avalanches.

  20. Spin and orbital moments in actinide compounds

    DEFF Research Database (Denmark)

    Lebech, B.; Wulff, M.; Lander, G.H.

    1991-01-01

    experiments designed to determine the magnetic moments at the actinide and transition-metal sublattice sites in compounds such as UFe2, NpCo2, and PuFe2 and to separate the spin and orbital components at the actinide sites. The results show, indeed, that the ratio of the orbital to spin moment is reduced......The extended spatial distribution of both the transition-metal 3d electrons and the actinide 5f electrons results in a strong interaction between these electron states when the relevant elements are alloyed. A particular interesting feature of this hybridization, which is predicted by single...

  1. In-the-plane design of an off-axis ophthalmic adaptive optics system using toroidal mirrors.

    Science.gov (United States)

    Liu, Zhuolin; Kocaoglu, Omer P; Miller, Donald T

    2013-01-01

    Adaptive optics (AO) ophthalmoscopes have garnered increased clinical and scientific use for imaging the microscopic retina. Unlike conventional ophthalmoscopes, however, AO systems are commonly designed with spherical mirrors that must be used off-axis. This arrangement causes astigmatism to accumulate at the retina and pupil conjugate planes, degrading AO performance. To mitigate this effect and more fully tap the benefit of AO, we investigated a novel solution based on toroidal mirrors. Derived 2(nd) order analytic solutions along with commercial ray tracing predict performance benefit of toroidal mirrors for ophthalmoscopic use. For the Indiana AO ophthalmoscope, a minimum of three toroids is required to achieve performance criteria for retinal image quality, beam displacement, and beam ellipticity. Measurements with fabricated toroids and retinal imaging on subjects substantiate the theoretical predictions. Comparison to off-the-plane method is also presented.

  2. Toroidally Resolved Structure of Divertor Heat Flux in RMP H-mode Discharges on DIII-D

    International Nuclear Information System (INIS)

    Jakubowski, M.W.; Evans, T.E.; Fenstermacher, M.E.; Lasnier, C.J.; Wolf, R.C.; Baylor, Larry R.; Boedo, J.A.; Burrell, K.H.; DeGrassie, J.S.; Gohil, P.; Mordijck, S.; Laengner, R.; Leonard, A.W.; Moyer, R.A.; Petrie, T.W.; Petty, C.C.; Pinsker, R.I.; Rhodes, T.L.; Schaffer, M.J.; Schmitz, O.; Snyder, P.B.; Stoschus, H.; Osborne, T.H.; Orlov, D.M.; Unterberg, Ezekial A.; Watkins, J.G.

    2011-01-01

    As shown on DIII-D edge localized modes (ELMs) can be either completely eliminated or mitigated with resonant magnetic perturbation (RMP) fields. Two infrared cameras, separated 105 degrees toroidally, were used to make simultaneous measurements of ELM heat loads with high frame rates. Without the RMP fields ELMs display a variety of different heat load dynamics and a range of toroidal variability that is characteristic of their 3D structure. Comparing radial averages there is no asymmetry between two toroidal locations. With RMP-mitigated ELMs, the variability in the radially averaged power loads is significantly reduced and toroidal asymmetries in power loads are introduced. In addition to RMP ELM suppression scenarios an RMP scenario with only very small ELMs and very good confinement has been achieved.

  3. Spontaneous subcapsular and perirrenal hemorrhage

    International Nuclear Information System (INIS)

    Fuster, M.J.; Saez, J.; Perez-Paya, F.J.; Fernandez, F.

    1997-01-01

    To assess the role of CT in the etiologic diagnosis of spontaneous subcapsular and perirrenal hemorrhage. The CT findings are described in 13 patients presenting subcapsular and perirrenal hemorrhage. Those patients in whom the bleeding was not spontaneous were excluded. Surgical confirmation was obtained in nine cases. In 11 of the 13 cases (84.6%), involving five adenocarcinomas, five angiomyolipoma, two complicated cysts and one case of panarterities nodosa, CT disclosed the underlying pathology. In two cases (15.4%), it only revealed the extension of the hematoma, but gave no clue to its origin. CT is the technique of choice when spontaneous subcapsular and perirrenal hemorrhage is suspected since, in most cases, it reveals the underlying pathology. (Author)

  4. Looped star polymers show conformational transition from spherical to flat toroidal shapes

    Science.gov (United States)

    Reiss, Pascal; Fritsche, Miriam; Heermann, Dieter W.

    2011-11-01

    Inspired by the topological organization of the circular Escherichia coli chromosome, which is compacted by separate domains, we study a polymer architecture consisting of a central ring to which either looped or linear side chains are grafted. A shape change from a spherical to a toroidal organization takes place as soon as the inner ring becomes large enough for the attached arms to fit within its circumference. Building up a torus, the system flattens, depending on the effective bending rigidity of the chain induced by entropic repulsion of the attached loops and, to a lesser extent, linear arms. Our results suggest that the natural formation of a toroidal structure with a decreased amount of writhe induced by a specific underlying topology could be one driving force, among others, that nature exploits to ensure proper packaging of the genetic material within a rod-shaped, bacterial envelope.

  5. Using numerical simulations to extract parameters of toroidal electron plasmas from experimental data

    DEFF Research Database (Denmark)

    Ha, B. N.; Stoneking,, M. R.; Marler, Joan

    2009-01-01

    Measurements of the image charge induced on electrodes provide the primary means of diagnosing plasmas in the Lawrence Non-neutral Torus II (LNT II) [Phys. Rev. Lett. 100, 155001 (2008)]. Therefore, it is necessary to develop techniques that determine characteristics of the electron plasma from...... features of the induced image charge signal. This paper presents a numerical study which finds that the frequency of the image charge signal due to the toroidal version of the m=1 diocotron mode is proportional to the total trapped charge and inversely proportional to magnetic field strength......, as in the cylindrical case. In the toroidal case, additional information about the m=1 motion of the plasma can be obtained by analysis of the image charge signal amplitude and shape. Finally, results from the numerical simulations are compared to experimental data from the LNT II and plasma characteristics...

  6. Modeling and control of plasma rotation for NSTX using neoclassical toroidal viscosity and neutral beam injection

    Energy Technology Data Exchange (ETDEWEB)

    Goumiri, I. R. [Princeton Univ., NJ (United States). Mechanical and Aerospace Dept.; Rowley, C. W. [Princeton Univ., NJ (United States). Mechanical and Aerospace Dept.; Sabbagh, S. A. [Columbia Univ., New York, NY (United States). Dept. of Applied Physics and Applied Mathematics; Gates, D. A. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Gerhardt, S. P. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Boyer, M. D. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Andre, R. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Kolemen, E. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Taira, K. [Florida State Univ, Dept Mech Engn, Tallahassee, FL USA.

    2016-02-19

    A model-based feedback system is presented to control plasma rotation in a magnetically confined toroidal fusion device, to maintain plasma stability for long-pulse operation. This research uses experimental measurements from the National Spherical Torus Experiment (NSTX) and is aimed at controlling plasma rotation using two different types of actuation: momentum from injected neutral beams and neoclassical toroidal viscosity generated by three-dimensional applied magnetic fields. Based on the data-driven model obtained, a feedback controller is designed, and predictive simulations using the TRANSP plasma transport code show that the controller is able to attain desired plasma rotation profiles given practical constraints on the actuators and the available measurements of rotation.

  7. Transport through dissipative trapped electron mode and toroidal ion temperature gradient mode in TEXTOR

    International Nuclear Information System (INIS)

    Rogister, A.; Hasselberg, G.; Waelbroeck, F.; Weiland, J.

    1987-12-01

    A self-consistent transport code is used to evaluate how plasma confinement in tokamaks is influenced by the microturbulent fields which are excited by the dissipative trapped electron (DTE) instability. As shown previously, the saturation theory on which the code is based has been developed from first principles. The toroidal coupling resulting from the ion magnetic drifts is neglected; arguments are presented to justify this approximation. The numerical results reproduce well the neo-Alcator scaling law observed experimentally - e.g. in TEXTOR - in non detached ohmic discharges, the confinement degradation which results when auxiliary heating is applied, as well as a large number of other experimental observations. We also assess the possible impact of the toroidal ion temperature gradient mode on energy confinement by estimating the ion thermal flux with the help of the mixing length approximation. (orig./GG)

  8. Influence of the magnetic toroidal field on the design of magnet systems for future fusion reactors

    International Nuclear Information System (INIS)

    Duchateau, J.L.

    2006-01-01

    It is often stated that an increase of the toroidal magnetic field on the plasma axis of tokamaks could be beneficial for future fusion reactors and will help in the economic viability of this new source of energy. After the development associated with ITER magnets regarding prototype conductors, joints and model coils, it is now possible to have a realistic approach of the design of magnet systems for fusion application and in particular of the toroidal field (TF) conductor design. This approach is meaningful since the ITER size is relevant to that of future fusion reactors. A demonstration reactor, the construction of which is supposed to start in 20 years would likely not be very different of ITER as for the magnet system

  9. MHD equilibrium of toroidal fusion plasma with stationary flows; Rownowaga MHD toroidalnej plazmy termojadrowej z przeplywami

    Energy Technology Data Exchange (ETDEWEB)

    Galkowski, A. [Institute of Atomic Energy, Otwock-Swierk (Poland)

    1994-12-31

    Non-linear ideal MHD equilibria in axisymmetric system with flows are examined, both in 1st and 2nd ellipticity regions. Evidence of the bifurcation of solutions is provided and numerical solutions of several problems in a tokamak geometry are given, exhibiting bifurcation phenomena. Relaxation of plasma in the presence of zero-order flows is studied in a realistic toroidal geometry. The field aligned flow allows equilibria with finite pressure gradient but with homogeneous temperature distribution. Numerical calculations have been performed for the 1st and 2nd ellipticity regimes of the extended Grad-Shafranov-Schlueter equation. Numerical technique, alternative to the well-known Grad`s ADM methods has been proposed to deal with slow adiabatic evolution of toroidal plasma with flows. The equilibrium problem with prescribed adiabatic constraints may be solved by simultaneous calculations of flux surface geometry and original profile functions. (author). 178 refs, 37 figs, 5 tabs.

  10. Photoelastic and analytical investigation of stress in toroidal magnetic field coils

    International Nuclear Information System (INIS)

    Pih, H.; Gray, W.H.

    1975-01-01

    A series of two-dimensional photoelastic stress analyses on circular and oval toroidal magnetic field coils for fusion reactors were made. The circumferential variation of the coil's magnetic force was simulated by applying different pressures to sixteen segmented regions of the inner surface of the models. Isochromatics and isoclinics were measured at selected points on the loaded model in a transmission polariscope using a microphotometer. Separate principal stresses were obtained using the combination of photoelastic information and isopachic data measured from the solution of Laplace's equation by the electrical analog method. Analysis of the same coil geometries, loadings, and boundary conditions were made using the finite element method. General agreement between theory and experiment was realized. From this investigation several variations of coil geometry and methods of support were evaluated. Based upon this experiment, suggestions for optimum structural design of toroidal field coils are presented

  11. Conceptual design of a high heat flux toroidal pumped limiter for Tore Supra

    International Nuclear Information System (INIS)

    Doceul, L.; Schlosser, J.; Chappuis, Ph.; Chatelier, M.; Cocat, J.P.; Deck, C.; Faisse, F.; Grosman, A.; Mitteau, R.; Tonon, G.

    1994-01-01

    In the frame of the Tore-Supra upgrade, where it is planned to inject up to 25 MW during a time up to 1000 s, a complete toroidal pumped limiter covered of CFC (Carbon Fiber Composite) tiles is being designed. The design is based on the important experience gained from the operation on Tore Supra of actively cooled plasma facing components and pumped limiters. This toroidal limiter covers 7.5 m 2 of the bottom part of the inner vessel and is composed of 576 elementary components. Each element is built from dispersion strengthened copper (DSCu) protected by brazed CFC flat tiles and cooled by pressurised water at 150 deg C. This limiter is designed to sustain 15 MW of convective power. (author) 7 refs.; 5 figs., 3 tabs

  12. Theoretical studies of the heating of toroidal plasmas with radio frequency electromagnetic radiation. Final report

    International Nuclear Information System (INIS)

    Glasser, A.H.; Swanson, D.G.; Wersinger, J.M.

    1982-01-01

    The continuation of a program of theoretical studies of the heating of toroidal plasmas with radio frequency (RF) electromagnetic radiation is proposed. Funding for this project first began on September 3, 1981, and will expire on April 2, 1982. A summary of the principal accomplishments of the first five months of the project is presented. These include the acquisition of computer terminals and modems, the implementation of existing codes on the MFECC C Cray Computer, the extension of the LHTOR lower hybrid toroidal ray tracing code to the full electromagnetic dispersion relation, the implementation of graphic output from the code, the beginning of extensive parameter studies, the beginning of an analytical treatment of the mode conversion layer associated with singular harmonic absorption, and the introduction of a graduate student into the program

  13. Physical mechanism determining the radial electric field and its radial structure in a toroidal plasma

    International Nuclear Information System (INIS)

    Ida, Katsumi; Miura, Yukitoshi; Itoh, Sanae

    1994-10-01

    Radial structures of plasma rotation and radial electric field are experimentally studied in tokamak, heliotron/torsatron and stellarator devices. The perpendicular and parallel viscosities are measured. The parallel viscosity, which is dominant in determining the toroidal velocity in heliotron/torsatron and stellarator devices, is found to be neoclassical. On the other hand, the perpendicular viscosity, which is dominant in dictating the toroidal rotation in tokamaks, is anomalous. Even without external momentum input, both a plasma rotation and a radial electric field exist in tokamaks and heliotrons/torsatrons. The observed profiles of the radial electric field do not agree with the theoretical prediction based on neoclassical transport. This is mainly due to the existence of anomalous perpendicular viscosity. The shear of the radial electric field improves particle and heat transport both in bulk and edge plasma regimes of tokamaks. (author) 95 refs

  14. Diocotron and Trivelpiece-Gould mode behavior in toroidal electron plasma

    Science.gov (United States)

    Stoneking, M. R.; Darrell, J. W.; Exarhos, S. A.; Patterson, A. S.; Price, M. J.; Wright, A. H.

    2013-03-01

    Electron plasma confined in a purely toroidal magnetic field supports analogs of the electrostatic normal modes observed in cylindrical traps - namely diocotron and Trivelpiece-Gould waves. The Lawrence Non-neutral Torus II (LNT II) device is used to study such waves. Electron plasma with densities in the range of 107 cm-3 persisting for about 1 second are produced in LNT II with high vacuum conditions (G. The plasma is diagnosed by monitoring image charge flow to sectors of the symmetric conducting boundary (major radius of 18 cm and minor radius of 3.8 cm). Damping of the m=1 (k=0) diocotron mode is explored to assess the extent to which rotational and/or magnetic pumping transport mechanisms are operative in toroidal electron plasma. Resonant standing wave plasma modes (m=0) are excited in order to determine the Trivelpiece-Gould dispersion relation. This work is supported by the National Science Foundation Grant PHY-0812893.

  15. Experimental study of toroidicity-induced Alfven eigenmode (TAE) stability at high q(0)

    Energy Technology Data Exchange (ETDEWEB)

    Batha, S.H.; Levinton, F.M. [Fusion Physics and Technology, Torrance, CA (United States); Spong, D.A. [Oak Ridge National Lab., TN (United States)] [and others

    1995-07-01

    Experiments to destabilize the Toroidicity-induced Alfven Eigenmode (TAE) by energetic alpha particles were performed on the Tokamak Fusion Test Reactor using deuterium and tritium fuel. To decrease the alpha particle pressure instability threshold, discharges with an elevated value of q(0) > 1.5 were used. By raising q(0), the radial location of the low toroidal-mode-number TAE gaps moves toward the magnetic axis and into alignment with the region of maximum alpha pressure gradient, thereby (in theory) lowering the value of {beta}{sub {alpha}}(0) required for instability. No TAE activity was observed when the central alpha particle {beta}{sub {alpha}} reached 0.08% in a discharge with fusion power of 2.4 MW. Calculations show that the fusion power is within a factor of 1.5 to 3 of the instability threshold.

  16. Highlights from the assembly of the helical field coils for the Advanced Toroidal Facility

    International Nuclear Information System (INIS)

    Benson, R.D.

    1985-01-01

    The helical field (HF) coils in the Advanced Toroidal Facility (ATF) device consist of a set of 24 identical segments connected to form a continuous pair of helical coils wrapped around a toroidal vacuum vessel. Each segment weighs approximately 1364 kg (3000 lb) and is composed of 14 water-cooled copper plate conductors bolted to a cast stainless steel structural support member with a T-shape cross section (known as the structural tee). The segment components are electrically insulated with Kapton adhesive tape, G-10, Tefzel, and rubber to withstand 2.5 kV. As a final insulator and structural support, the entire segment is vacuum impregnated with epoxy. This paper offers a brief overview of the processes used to assemble the component parts into a completed segment, including identification of items that required special attention. 4 figs

  17. Transport and dynamcis in toroidal fusion systems. Final report, 1992--1995

    International Nuclear Information System (INIS)

    Schnack, D.D.

    1995-01-01

    This document is organized as follows. Discussions are presented on the properties of structured and unstructured meshes, and the data structures useful for describing them. Issues related to the triangulation of an arbitrary set of points in a plane are also discussed. A derivation is made of a finite volume approximation to the resistive MHD equations suitable for use on an unstructured, triangular mesh in toroidal geometry. Boundary conditions are discussed. The specific MHD model, and its implementation on the unstructured mesh, is discussed. A discussion is presented of methods of time integration, and descriptions are given for implementation of semi-implicit and fully implicit algorithms. Examples of the application of the method are given. Included are standard, two- dimensional hydrodynamic and MHD shock problems, as well as applications of the method to the equilibrium and stability of toroidal fusion plasmas in two and three dimensions. The initial results with mesh adaptation are also described

  18. Observation of a new toroidally localized kink mode and its role in reverse-field--pinch plasmas

    International Nuclear Information System (INIS)

    Tamano, T.; Bard, W.D.; Chu, C.; Kondoh, Y.; La Haye, R.J.; Lee, P.S.; Saito, M.; Schaffer, M.J.; Taylor, P.L.

    1987-01-01

    A new type of toroidally localized kink instability, which we named the ''slinky mode,'' was observed in a reversed-field--pinch plasma in the OHTE (Ohmic heating toroidal experiment) device. It is found that the slinky mode is the result of the phase locking of several internal kink modes due to nonlinear coupling and is an effective way to approach the Taylor relaxed state

  19. Relativistic expressions for current electric moments of nuclei

    International Nuclear Information System (INIS)

    Silenko, A.J.

    2000-01-01

    Relativistic expressions for the operators of current electric moments caused by electromagnetic spin-orbit interaction are obtained. Formulas for the matrix elements of the current electric moments of nuclei are derived. The contributions of the current electric moments to the quadrupole moment of the deuteron and to its root-mean-square radius are calculated with allowance for relativistic effects

  20. Relativistic expressions for electric current moments of nuclei

    International Nuclear Information System (INIS)

    Silenko, A.Ya.

    2000-01-01

    The relativistic expressions for electric current moments operators, due to the electromagnetic spin-orbital interaction, are obtained. The formulae for matrix elements of nuclear electric current moments are deduced. The contributions of electric current moments to both quadrupole moment and root-mean-square radius of deuteron are calculated with the account of the relativistic effects [ru