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Sample records for axisymmetric tandem mirror

  1. Axisymmetric Tandem Mirrors: Stabilization and Confinement Studies

    International Nuclear Information System (INIS)

    The 'Kinetic Stabilizer' has been proposed as a means of MHD stabilizing an axisymmetric tandem mirror system. The K-S concept is based on theoretical studies by Ryutov, confirmed experimentally in the Gas Dynamic Trap experiment in Novosibirsk. In the K-S beams of ions are directed into the end of an 'expander' region outside the outer mirror of a tandem mirror. These ions, slowed, stagnated, and reflected as they move up the magnetic gradient, produce a low-density stabilizing plasma.At the Lawrence Livermore National Laboratory we have been conducting theoretical and computational studies of the K-S Tandem Mirror. These studies have employed a low-beta code written especially to analyze the beam injection/stabilization process,and a new code SYMTRAN (by Hua and Fowler)that solves the coupled radial and axial particle and energy transport in a K-S T-M. Also, a 'legacy' MHD stability code, FLORA, has been upgraded and employed to benchmark the injection/stabilization code and to extend its results to high beta values.The FLORA code studies so far have confirmed the effectiveness of the K-S in stabilizing high-beta (40%) plasmas with stabilizer plasmas the peak pressures of which are several orders of magnitude smaller than those of the confined plasma.Also the SYMTRAN code has shown D-T plasma ignition from alpha particle energy deposition in T-M regimes with strong end plugging.Our studies have confirmed the viability of the K-S T-M concept with respect to MHD stability and radial and axial confinement. We are continuing these studies in order to optimize the parameters and to examine means for the stabilization of possible residual instability modes, such as drift modes and 'trapped-particle' modes. These modes may in principle be controlled by tailoring the stabilizer plasma distribution and/or the radial potential distribution.In the paper the results to date of our studies are summarized and projected to scope out possible fusion-power versions of the K-S T-M

  2. Axisymmetric Tandem Mirrors: Stabilization and Confinement Studies

    International Nuclear Information System (INIS)

    The 'Kinetic Stabilizer' has been proposed as a means of MHD stabilizing an axisymmetric tandem mirror system. The K-S concept is based on theoretical studies by Ryutov, confirmed experimentally in the Gas Dynamic Trap experiment in Novosibirsk. In the K-S beams of ions are directed into the end of an 'expander' region outside the outer mirror of a tandem mirror. These ions, slowed, stagnated, and reflected as they move up the magnetic gradient, produce a low-density stabilizing plasma. At the Lawrence Livermore National Laboratory we have been conducting theoretical and computational studies of the K-S Tandem Mirror. These studies have employed a low-beta code written especially to analyze the beam injection/stabilization process, and a new code SYMTRAN (by Hua and Fowler) that solves the coupled radial and axial particle and energy transport in a K-S TM. Also, a 'legacy' MHD stability code, FLORA, has been upgraded and employed to benchmark the injection/stabilization code and to extend its results to high beta values. The FLORA code studies so far have confirmed the effectiveness of the K-S in stabilizing high-beta (40%) plasmas with stabilizer plasmas the peak pressures of which are several orders of magnitude smaller than those of the confined plasma. Also the SYMTRAN code has shown D-T plasma ignition from alpha particle energy deposition in T-M regimes with strong end plugging. Our studies have confirmed the viability of the K-S-T-M concept with respect to MHD stability and radial and axial confinement. We are continuing these studies in order to optimize the parameters and to examine means for the stabilization of possible residual instability modes, such as drift modes and 'trapped-particle' modes. These modes may in principle be controlled by tailoring the stabilizer plasma distribution and/or the radial potential distribution. In the paper the results to date of our studies are summarized and projected to scope out possible fusion-power versions of the K

  3. Potential formation in axisymmetrized tandem mirror GAMMA 10

    International Nuclear Information System (INIS)

    The paper reports experimental results on potential formation and end plugging in the axisymmetrized tandem mirror GAMMA 10. The plugging at both ends has been achieved by a combination of neutral beams and gyrotrons. The presence of a plug potential with a thermal barrier in an axisymmetric mirror has been confirmed by direct measurement of the axial potential profile. Enhancement of axial particle confinement has been observed during the end plugging. Non-ambipolar radial transport has been greatly reduced in the axisymmetrized magnetic configuration. The potentials measured by beam probes and end loss analysers are 0.7, 0.4 and 1.1 kV in the central, barrier and plug regions, respectively. Strong end plugging is observed when the central-cell density is higher than the densities in the plug and the barrier, and the plug density remains higher than the barrier density. The plug electron temperature is higher than the central temperature. Hot electrons forming a football-shaped profile have been stably produced in the axisymmetric mirror. The beta value and the fraction of the hot electrons reach up to 5% and 0.8, respectively. Central-cell ion-cyclotron resonance heating can sustain a stable plasma with higher density and ion temperature when resonance surfaces exist in both the anchor and the central cells. (author)

  4. The Axisymmetric Tandem Mirror: A Magnetic Mirror Concept Game Changer Magnet Mirror Status Study Group

    Energy Technology Data Exchange (ETDEWEB)

    Simonen, T; Cohen, R; Correll, D; Fowler, K; Post, D; Berk, H; Horton, W; Hooper, E B; Fisch, N; Hassam, A; Baldwin, D; Pearlstein, D; Logan, G; Turner, B; Moir, R; Molvik, A; Ryutov, D; Ivanov, A A; Kesner, J; Cohen, B; McLean, H; Tamano, T; Tang, X Z; Imai, T

    2008-10-24

    Experimental results, theory and innovative ideas now point with increased confidence to the possibility of a Gas Dynamic Trap (GDT) neutron source which would be on the path to an attractively simple Axisymmetric Tandem Mirror (ATM) power plant. Although magnetic mirror research was terminated in the US 20 years ago, experiments continued in Japan (Gamma 10) and Russia (GDT), with a very small US effort. This research has now yielded data, increased understanding, and generated ideas resulting in the new concepts described here. Early mirror research was carried out with circular axisymmetric magnets. These plasmas were MHD unstable due to the unfavorable magnetic curvature near the mid-plane. Then the minimum-B concept emerged in which the field line curvature was everywhere favorable and the plasma was situated in a MHD stable magnetic well (70% average beta in 2XII-B). The Ioffe-bar or baseball-coil became the standard for over 40 years. In the 1980's, driven by success with minimum-B stabilization and the control of ion cyclotron instabilities in PR6 and 2XII-B, mirrors were viewed as a potentially attractive concept with near-term advantages as a lower Q neutron source for applications such as a hybrid fission fuel factory or toxic waste burner. However there are down sides to the minimum-B geometry: coil construction is complex; restraining magnetic forces limit field strength and mirror ratios. Furthermore, the magnetic field lines have geodesic curvature which introduces resonant and neoclassical radial transport as observed in early tandem mirror experiments. So what now leads us to think that simple axisymmetric mirror plasmas can be stable? The Russian GDT experiment achieves on-axis 60% beta by peaking of the kinetic plasma pressure near the mirror throat (where the curvature is favorable) to counter-balance the average unfavorable mid-plane curvature. Then a modest augmentation of plasma pressure in the expander results in stability. The GDT

  5. The Axisymmetric Tandem Mirror: A Magnetic Mirror Concept Game Changer Magnet Mirror Status Study Group

    International Nuclear Information System (INIS)

    Experimental results, theory and innovative ideas now point with increased confidence to the possibility of a Gas Dynamic Trap (GDT) neutron source which would be on the path to an attractively simple Axisymmetric Tandem Mirror (ATM) power plant. Although magnetic mirror research was terminated in the US 20 years ago, experiments continued in Japan (Gamma 10) and Russia (GDT), with a very small US effort. This research has now yielded data, increased understanding, and generated ideas resulting in the new concepts described here. Early mirror research was carried out with circular axisymmetric magnets. These plasmas were MHD unstable due to the unfavorable magnetic curvature near the mid-plane. Then the minimum-B concept emerged in which the field line curvature was everywhere favorable and the plasma was situated in a MHD stable magnetic well (70% average beta in 2XII-B). The Ioffe-bar or baseball-coil became the standard for over 40 years. In the 1980's, driven by success with minimum-B stabilization and the control of ion cyclotron instabilities in PR6 and 2XII-B, mirrors were viewed as a potentially attractive concept with near-term advantages as a lower Q neutron source for applications such as a hybrid fission fuel factory or toxic waste burner. However there are down sides to the minimum-B geometry: coil construction is complex; restraining magnetic forces limit field strength and mirror ratios. Furthermore, the magnetic field lines have geodesic curvature which introduces resonant and neoclassical radial transport as observed in early tandem mirror experiments. So what now leads us to think that simple axisymmetric mirror plasmas can be stable? The Russian GDT experiment achieves on-axis 60% beta by peaking of the kinetic plasma pressure near the mirror throat (where the curvature is favorable) to counter-balance the average unfavorable mid-plane curvature. Then a modest augmentation of plasma pressure in the expander results in stability. The GDT

  6. Magnetic design of the axisymmetric throttle-coil addition to the tandem mirror experiment-upgrade

    International Nuclear Information System (INIS)

    The TMX-U magnet set has incorporated new axisymmetric throttle coils and fan-reversing transition magnets. This new magnet geometry, which will allow for the experimental verification of new physics issues related to axicell tandem mirrors, encompasses both engineering and physics considerations. Engineering considerations include structural integrity plus neutral beam and diagnostic access. Physics issues include the stability and radial transport of the confined plasma. We have calculated the magnetic field using the magnetic field code, EFFI, and the plasma stability and surface curvatures using the plasma stability code, TEBASCO. Our magnet design allows the axisymmetric throttle mirror to be varied from the end-cell mirror value of 2 to a peak of 6 T

  7. Alpha particle confinement in tandem mirrors

    International Nuclear Information System (INIS)

    Mechanisms leading to loss of alpha particles from non-axisymmetric tandem mirrors are considered. Stochastic diffusion due to bounce-drift resonances, which can cause rapid radial losses of high-energy alpha particles, can be suppressed by imposing a 20% rise in axisymmetric fields before the quadrupole transition sections. Alpha particles should then be well-confined until thermal energies when they enter the resonant plateau require. A fast code for computation of drift behavior in reactors is described. Sample calculations are presented for resonant particles in a proposed coil set for the Tandem Mirror Next Step

  8. Tandem mirror fusion research

    International Nuclear Information System (INIS)

    The tandem mirror program has evolved considerably in the last decade. Of significance is the viable reactor concept embodied in the MARS design. An aggressive experimental program, culminating in the operation of MFTF-B in late 1986, will provide a firm basis for refining the MARS design as necessary for constructing a reactor prototype in the 1990s

  9. Negative tandem mirror

    International Nuclear Information System (INIS)

    A tandem mirror configuration can be created by combining hot electron end cell plasmas with neutral beam pumping. A region of large negative potential formed in each end cell confines electrons in the central cell. The requirement of charge neutrality causes the central cell potential to become negative with respect to ground in order to confine ions as well as electrons. We discuss the method of producing and calculating the desired axial potential profile, and show the calculated axial potential profile and plasma parameters for a negative configuration of TMX-Upgrade

  10. Compact neutron imaging system using axisymmetric mirrors

    Science.gov (United States)

    Khaykovich, Boris; Moncton, David E; Gubarev, Mikhail V; Ramsey, Brian D; Engelhaupt, Darell E

    2014-05-27

    A dispersed release of neutrons is generated from a source. A portion of this dispersed neutron release is reflected by surfaces of a plurality of nested, axisymmetric mirrors in at least an inner mirror layer and an outer mirror layer, wherein the neutrons reflected by the inner mirror layer are incident on at least one mirror surface of the inner mirror layer N times, wherein N is an integer, and wherein neutrons reflected by the outer mirror are incident on a plurality of mirror surfaces of the outer layer N+i times, where i is a positive integer, to redirect the neutrons toward a target. The mirrors can be formed by a periodically reversed pulsed-plating process.

  11. Magneto-hydrodynamically stable axisymmetric mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Ryutov, D. D.; Cohen, B. I.; Molvik, A. W. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Berk, H. L. [University of Texas, Austin, Texas 78712 (United States); Simonen, T. C. [University of California, Berkeley, California 94720 (United States)

    2011-09-15

    Making axisymmetric mirrors magnetohydrodynamically (MHD) stable opens up exciting opportunities for using mirror devices as neutron sources, fusion-fission hybrids, and pure-fusion reactors. This is also of interest from a general physics standpoint (as it seemingly contradicts well-established criteria of curvature-driven instabilities). The axial symmetry allows for much simpler and more reliable designs of mirror-based fusion facilities than the well-known quadrupole mirror configurations. In this tutorial, after a summary of classical results, several techniques for achieving MHD stabilization of the axisymmetric mirrors are considered, in particular: (1) employing the favorable field-line curvature in the end tanks; (2) using the line-tying effect; (3) controlling the radial potential distribution; (4) imposing a divertor configuration on the solenoidal magnetic field; and (5) affecting the plasma dynamics by the ponderomotive force. Some illuminative theoretical approaches for understanding axisymmetric mirror stability are described. The applicability of the various stabilization techniques to axisymmetric mirrors as neutron sources, hybrids, and pure-fusion reactors are discussed; and the constraints on the plasma parameters are formulated.

  12. SYMTRAN - A Time-dependent Symmetric Tandem Mirror Transport Code

    International Nuclear Information System (INIS)

    A time-dependent version of the steady-state radial transport model in symmetric tandem mirrors in Ref. [1] has been coded up and first tests performed. Our code, named SYMTRAN, is an adaptation of the earlier SPHERE code for spheromaks, now modified for tandem mirror physics. Motivated by Post's new concept of kinetic stabilization of symmetric mirrors, it is an extension of the earlier TAMRAC rate-equation code omitting radial transport [2], which successfully accounted for experimental results in TMX. The SYMTRAN code differs from the earlier tandem mirror radial transport code TMT in that our code is focused on axisymmetric tandem mirrors and classical diffusion, whereas TMT emphasized non-ambipolar transport in TMX and MFTF-B due to yin-yang plugs and non-symmetric transitions between the plugs and axisymmetric center cell. Both codes exhibit interesting but different non-linear behavior

  13. Fueling of tandem mirror reactors

    International Nuclear Information System (INIS)

    This paper summarizes the fueling requirements for experimental and demonstration tandem mirror reactors (TMRs), reviews the status of conventional pellet injectors, and identifies some candidate accelerators that may be needed for fueling tandem mirror reactors. Characteristics and limitations of three types of accelerators are described; neutral beam injectors, electromagnetic rail guns, and laser beam drivers. Based on these characteristics and limitations, a computer module was developed for the Tandem Mirror Reactor Systems Code (TMRSC) to select the pellet injector/accelerator combination which most nearly satisfies the fueling requirements for a given machine design

  14. Introduction to tandem mirror physics

    International Nuclear Information System (INIS)

    This monograph, prepared jointly by the MIT Plasma Fusion Center Mirror Fusion group and SAI, Boulder, Colorado, presents a review of the development of mirror fusion theory from its conception some thirty years ago to the present. Pertinent historic experiments and their contribution are discussed to set the stage for a detailed analysis of current experiments and the problems which remain to be solved in bringing tandem mirror magnetic confinement fusion to fruition. In particular, Chapter III discusses in detail the equilibrium and stability questions which must be dealt with before tandem mirror reactors become feasible, while Chapters IV and V discuss some of the current machines and those under construction which will help to resolve critical issues in both physics and engineering whose solutions are necessary to the commercialization of tandem mirror fusion

  15. TARA tandem mirror reactor design study

    International Nuclear Information System (INIS)

    A point design is presented for a tandem mirror reactor based upon a TARA plug configuration in which a potential plug for center cell ions is created in an axisymmetric cell adjacent to the center cell. We will incorporate the same center cell as the MARS design, allowing a direct comparison of the different plug configurations. The study will include a magnet design that satisfied the reactor criteria for circular flux surfaces at the center cell plasma edge, stability against ballooning, trapped particle and interchange modes, and zero net parallel currents. We will also present a self-consistent power balance of the reactor, and compare the reactor's energy amplification factor Q and technological requirements with the MARS design

  16. Theoretical studies in tandem mirror physics

    International Nuclear Information System (INIS)

    Recent developments in six areas of tandem-mirror theory are explored. Specifically, FLR terms (including electric-field drift) have been added to our 3-D paraxial MHD equilibrium code. Our low-frequency MHD stability analysis with FLR, which previously included only m/sub theta/ = 1 rigid perturbations, has been extended to incorporate moderate m/sub theta/, rotational drive, finite-beta effects on wall stabilization, and the well-digging effect of energetic electrons by using three computational techniques. In addition, we have examined the microstability of relativistic electrons with a loss-cone distribution, emphasizing the whistler and cyclotron-maser instabilities. We have also studied techniques for controlling radial transport, including the floating of segmented end plates and the tuning of transition-region coils, and have quantified the residual transport in a tandem mirror with axisymmetric throttle coils. Earlier work on the effect of ECRH on potentials in thermal-barrier cells has been extended. The transition between the weak- and strong-heating regimes has been examined using Fokker-Planck and Monte Carlo codes; an analytic model for the potentials relative to the end wall has been developed. Finally, our investigation of drift-frequency pumping of thermal-barrier ions has demonstrated that pumping is optimized when the magnetic fluctuation is perpendicular to both the unperturbed field and the thin fan, and that an adequate pumping rate is obtainable in future machines

  17. Tandem mirror technology demonstration facility

    International Nuclear Information System (INIS)

    This report describes a facility for generating engineering data on the nuclear technologies needed to build an engineering test reactor (ETR). The facility, based on a tandem mirror operating in the Kelley mode, could be used to produce a high neutron flux (1.4 MW/M2) on an 8-m2 test area for testing fusion blankets. Runs of more than 100 h, with an average availability of 30%, would produce a fluence of 5 mW/yr/m2 and give the necessary experience for successful operation of an ETR

  18. Tandem mirror technology demonstration facility

    Energy Technology Data Exchange (ETDEWEB)

    1983-10-01

    This report describes a facility for generating engineering data on the nuclear technologies needed to build an engineering test reactor (ETR). The facility, based on a tandem mirror operating in the Kelley mode, could be used to produce a high neutron flux (1.4 MW/M/sup 2/) on an 8-m/sup 2/ test area for testing fusion blankets. Runs of more than 100 h, with an average availability of 30%, would produce a fluence of 5 mW/yr/m/sup 2/ and give the necessary experience for successful operation of an ETR.

  19. Small, octopole-stabilized tandem mirror reactor

    International Nuclear Information System (INIS)

    It is shown that the use of octopole stabilization in a tandem mirror allows a large reduction in end-cell length. A novel feature of the method proposed in this report is the placement of the minimum IBI region coonsiderably off axis, thus rendering the core plasma more axisymmetric. The region from the core to the field minimum is bridged by a mirror-confined hot-electron mantle. Low β, ideal magnetohydrodynamic stability, as evaluated with the interchange criterion, yields an upper limit to the required mantle peak β of 78% for a center-cell peak β of 75% and barrier peak β of 30%. Estimates for the worst type of classical radial diffusion - with stochastic displacements per bounce - show that such radial losses are negligible for this configuration. First estimates of power balance indicate Q approx. 10 for a reactor producing 500 MW of fusion power and Q approx. 25 for one producing 1000 MW, using conservative assumptions regarding mantle β requirements and synchrotron radiation losses

  20. Parametric studies of tandem mirror reactors

    International Nuclear Information System (INIS)

    This report, along with its companion, An Improved Tandem Mirror Reactor, discusses the recent progress and present status of our tandem mirror reactor studies. This report presents the detailed results of parametric studies up to, but not including, the very new ideas involving thermal barriers

  1. Tandem mirror next step conceptual design

    International Nuclear Information System (INIS)

    A study was made to define the features of the experimental mirror fusion device - The Tandem Mirror Next Step, or TMNS - that will bridge the gap between present mirror confinement experiments and a power-producing reactor. We outline the project goals, describe some initial device parameters, and relate the technological requirements to ongoing development programs

  2. The Kinetic Stabilizer: A Route to Simpler Tandem Mirror Systems?

    Energy Technology Data Exchange (ETDEWEB)

    Post, R

    2001-05-30

    This paper discusses a new approach to an MHD stabilizing technique for magnetic fusion systems of the axisymmetric ''open-ended'' variety. The concept is adaptable to tandem-mirror systems and would result in a major simplification of such systems, accompanied by a substantial improvement in their confinement characteristics, The paper first discusses the present impetus to find a simpler and less expensive route to fusion than that offered by the mainline approach, the tokamak. The history of magnetic fusion research shows that closed and open systems exhibit very different confinement characteristics. Closed systems, such as the tokamak, the stellarator, or the reversed-field pinch have cross-field transport that is dominated by plasma turbulence. By contrast, there are examples of open-systems where turbulence, if present at all, was at such low levels that the transport agreed with ''classical'' predictions. The clearest examples are ones in which the field geometry was axiymmetric. However axisymmetric mirror systems are subject to MHD instability. Thus in the years following the famous Ioffe experiment, most open systems have employed asymmetric magnetic fields, with attendant problems of complexity and enhanced cross-field transport. This paper proposes a new means of stabilizing axisymmetric mirror-based systems. The idea, called the ''Kinetic Stabilizer'' has roots in experiments performed with the axisymmetric Gas Dynamic Trap at Novosibirsk. In these experiments, performed in a high collisionality plasma regime, it was shown that the presence of the effluent plasma in the positive-curvature expanding-field region outside the mirrors was effective in stabilizing a high-beta (30 percent) confined plasma against MHD modes. In the plasmas of tandem-mirror systems the density of the effluent plasma is too low to employ this method of stabilization. The Kinetic Stabilizer solves this problem by using

  3. ICRF wave propagation and absorption in axisymmetric mirrors. Progress report, July 1-November 30, 1985

    International Nuclear Information System (INIS)

    A numerical code called GARFIELD has been developed to calculate the structure of ICRF electric fields in axisymmetric mirrors. It is being used to investigate ICRF wave structure of central cells of tandem mirror experiments. Fields are solved on a 2-D grid in the axial and radial directions. This permits us to study the effect that axial as well as radial variations of the magnetic field and density have on ICRF wave propagation and absorption. Much of this time frame was spent writing the code and refining the numerics. Initial calculations have been completed for the Phaedrus tandem mirror. These show that there is an evanescent fast wave structure in the radial direction, a standing wave formation in the axial direction, and a small amount of propagating ion cyclotron wave towards a shallow magnetic beach in the center of the mirror

  4. Tandem Mirror Reactor Systems Code (Version I)

    International Nuclear Information System (INIS)

    A computer code was developed to model a Tandem Mirror Reactor. Ths is the first Tandem Mirror Reactor model to couple, in detail, the highly linked physics, magnetics, and neutronic analysis into a single code. This report describes the code architecture, provides a summary description of the modules comprising the code, and includes an example execution of the Tandem Mirror Reactor Systems Code. Results from this code for two sensitivity studies are also included. These studies are: (1) to determine the impact of center cell plasma radius, length, and ion temperature on reactor cost and performance at constant fusion power; and (2) to determine the impact of reactor power level on cost

  5. Tandem mirror plasma confinement apparatus

    International Nuclear Information System (INIS)

    Apparatus and method are described for confining a plasma in a center mirror cell by use of two end mirror cells as positively charged end stoppers to minimize leakage of positive particles from the ends of the center mirror cell

  6. Plasma performance study for the tandem mirror reactor

    International Nuclear Information System (INIS)

    A computer code was developed for assessing the performance of new variations on the thermal barrier idea for tandem mirror reactors (TMR's). The code solves the particle and energy balance equations simultaneously for each species of particles in each portion of the machine. The code is thus able to determine the neutral beam and ECRH injection powers that are required to sustain an equilibrium situation, and, from these, to determine the machine's Q value. This paper focuses on the methodology and numerical algorithms used in accomplishing this solution. We plan to use this code to compare the A-cell barrier TMR with axisymmetric TMR's

  7. Tandem mirror and field-reversed mirror experiments

    Energy Technology Data Exchange (ETDEWEB)

    Coensgen, F.H.; Simonen, T.C.; Turner, W.C.

    1979-08-21

    This paper is largely devoted to tandem mirror and field-reversed mirror experiments at the Lawrence Livermore Laboratory (LLL), and briefly summarizes results of experiments in which field-reversal has been achieved. In the tandem experiment, high-energy, high-density plasmas (nearly identical to 2XIIB plasmas) are located at each end of a solenoid where plasma ions are electrostatically confined by the high positive poentials arising in the end plug plasma. End plug ions are magnetically confined, and electrons are electrostatically confined by the overall positive potential of the system. The field-reversed mirror reactor consists of several small field-reversed mirror plasmas linked together for economic reasons. In the LLL Beta II experiment, generation of a field-reversed plasma ring will be investigated using a high-energy plasma gun with a transverse radial magnetic field. This plasma will be further heated and sustained by injection of intense, high-energy neutral beams.

  8. Plasma confinement in the GAMMA 10 tandem mirror

    International Nuclear Information System (INIS)

    The central-cell density and the diamagnetic signal were doubled due to plug potential formation by ECRH in the hot ion mode experiments on the GAMMA 10 tandem mirror. In order to obtain these remarkable results, the axisymmetrized heating patterns of ECRH and ICRF were optimized. Furthermore, conducting plates were installed adjacent to the surface of the plasma along the flat shaped magnetic flux tube located at the anchor transition regions; the plates may contribute to reduce some irregular electric fields produced possibly with ECRH in these thin flux tube regions. The conducting plates contributed to the reduction of the radial loss rate to be less than 3% of the total particle losses along with the improvements in the reproducibility of the experiments and the controllability of the potential confinement. The increases in the central-cell density and the diamagnetism in association with the increase in the plug potentials scaled well with increasing the ECRH powers. A plug potential of 0.6 kV and a density increase of 100% were achieved using an ECRH power of 140 kW injected into both plug regions. The plasma confinement was improved by an order of magnitude over a simple mirror confinement due to the tandem mirror potential formation. (author)

  9. From x-ray telescopes to neutron scattering: using axisymmetric mirrors to focus a neutron beam

    OpenAIRE

    Khaykovich, B.; Gubarev, M. V.; Bagdasarova, Y.; Ramsey, B. D.; Moncton, D.E.

    2012-01-01

    We demonstrate neutron beam focusing by axisymmetric mirror systems based on a pair of mirrors consisting of a confocal ellipsoid and hyperboloid. Such a system, known as a Wolter mirror configuration, is commonly used in x-ray telescopes. The axisymmetric Wolter geometry allows nesting of several mirror pairs to increase collection efficiency. We have implemented a system containing four nested Ni mirror pairs, which was tested by focusing a polychromatic neutron beam at the MIT Reactor. In ...

  10. The ''Kinetic Stabilizer'': A Simpler Tandem Mirror Confinement?

    International Nuclear Information System (INIS)

    ion beams are injected along the field lines in such a way as to be reflected before they reach the mirrors, thus forming a localized peak in the plasma density. It will be shown that the power required to produce these stabilizing plasmas is much less than the power per meter of fusion power systems that might employ this technique. Use of the Kinetic Stabilizer idea may therefore permit the construction of tandem mirror fusion power systems that are much smaller and simpler than those based on the use of non-axisymmetric fields to achieve MHD stability

  11. Current results of the tandem mirror experiment

    International Nuclear Information System (INIS)

    The basic operating characteristics of the Tandem Mirror Experiment, (TMX) at the Lawrence Livermore Laboratory in the USA have been established. Tandem-mirror plasmas have been produced using neutral-beam-fueled end plugs and a gas-fueled center cell. An axial potential well between the end plugs has been measured. There is direct evidence that this potential well enhances the axial confinement of the center-cell ions. The observed densities and loss currents are consistent with preliminary studies of the particle sources and losses near the magnetic axis. The observed confinement is consistent with theory when plasma fluctuations are low. When the requirement of drift-cyclotron loss-cone mode stability is violated, the plasma fluctuations degrade the center-cell confinement

  12. Progress in the tandem mirror program

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, T.K.; Borchers, R.R.

    1981-09-13

    Experimental results in TMX have confirmed the basic principles of the tandem-mirror concept. A center-cell particle confinement parameter eta tau approx. 10/sup 11/ cm/sup -3/ s has been obtained at ion temperatures around 100 eV, which is a hundred-fold improvement over single mirrors at the same temperatures. For TMX these results have been obtained at peak beta values in the center cell in the range 10 to 40%, not yet limited by MHD activity; and ion-cyclotron resonant heating (ICRH) in the Phaedrus tandem-mirror experiment has produced beta values approx. 25%, which is several times the ideal MHD limit for that device. In addition, it has been demonstrated that the end fan chambers of TMX simultaneously isolate the hot electrons from the end walls, provide adequate pumping and conveniently dispose of the exhaust plasma energy either by thermal deposition on the end wall or by direct conversion to electricity (at 48% efficiency in agreement with calculations). Also, evidence was obtained for inherent divertor action in TMX, presumably in part responsible for the observed low impurity level (<0.5% low-Z ions in the center cell).

  13. Recent results from the Tara tandem mirror and the Constance-B mirror

    International Nuclear Information System (INIS)

    The Tara tandem mirror program has studied anchor and ponderomotive stabilization, axicell plugging with ECH and ICRF, sloshing ion buildup in the axicells, and halo formation and stabilization by an axisymmetric divertor. Central cell plasma parameters achieved by midplane fueling and slow wave ICRF heating from a local magnetic hill are β = 1.2%, ne = 3x1012cm-3. The plasma is stabilized both by anchor ion β and by ponderomotive stabilization with the central cell ICRF in combination with a magnetic divertor, realizing a completely axisymmetric configuration. Anchor ICRF creates non-Boltzmann potential plugging of central cell ions. Neutral beam injection establishes a sloshing ion distribution for a cold dense cell stream; the hot ion confinement is classical and dominated by electron drag. Axicell ECH plugging experiments lead to near total reduction in endloss, but also to a decrease in the central cell density, indicating increased radial losses. Single ended ECH plugging shows no increase in opposite endloss. Single-ended plugging with axicell ICRF produces 50% reduction in ion endloss, with about half of the reflected ions observed in the opposite endloss. In the Constance-B quadrupole mirror the hot electron pressure profile is peaked off-axis and has the shape of a baseball seam. (author)

  14. Some new ideas for Tandem Mirror blankets

    International Nuclear Information System (INIS)

    The Tandem Mirror Reactor, with its cylindrical central cell, has led to numerous blanket designs taking advantage of the simple geometry. Also many new applications for fusion neutrons are now being considered. To the pure fusion electricity producers and hybrids producing fissile fuel, we are adding studies of synthetic fuel producers and fission-suppressed hybrids. The three blanket concepts presented are new ideas and should be considered illustrative of the breadth of Livermore's application studies. They are not meant to imply fully analyzed designs

  15. Stabilization of axisymmetric mirror plasmas by energetic ion injection

    International Nuclear Information System (INIS)

    Plasmas in axisymmetric mirror devices can be made stable to MHD interchange modes by injecting energetic ions which contribute significantly to the pressure and spend a sufficiently large fraction of a bounce time in regions of favorable curvature. Pitch-angle scattering adversely affects the method by reducing this fraction. The ions must be sufficiently energetic that pitch-angle scattering is not detrimental for that part of a slowing-down time during which they contribute significantly to the pressure. We have solved the bounce-averaged Fokker-Planck equation, including drag and pitch-angle scattering, and calculated the energetic ion contribution to the stability integral. With specially tailored magnetic fields, the required injection energy and power drain are found to be reasonable

  16. Remote maintenance of tandem mirror hybrid coils

    International Nuclear Information System (INIS)

    Hybrid Coils (superconducting coils with normal conducting inserts) are being employed with increasing frequency on Tandem Mirror Devices to obtain high field strengths. The normal conducting copper inserts are short lived in comparison to their encircling superconductors. It becomes desirable, therefore, to devise design features and maintenance procedures to replace the inner normal conducting coils without simultaneously replacing the longer lived (and significantly more costly) superconducting coils. The high neutron wall loadings require that the task be accomplished by remote control. The approach is to permanently mount the coil assemblies on track mounted carriages which serve, during machine operation merely as structural supports, but during maintenance procedures as moveable transport devices. The carriages incorporate all necessary provisions to facilitate remote maintenance operations and to adjust and align the coil assemblies with respect to adjacent machine components. The vacuum vessel is severed on both sides of the hybrid coil by means of a remote cutting machine. The entire coil is transported horizontally, normal to the machine axis to a nearby repair station. Prepositioned carriage mounted repair equipment at the repair station withdraws the damaged normal coil as a single entity and inserts a preassembled spare unit. The repaired hybrid coil is reassembled to the reactor. A cost and risk effective procedure has been evolved to maintain one of the more critical components of a Tandem Mirror Machine

  17. MHD-Stabilization of Axisymmetric Mirror Systems Using Pulsed ECRH

    Energy Technology Data Exchange (ETDEWEB)

    Post, R F

    2009-11-20

    This paper, part of a continuing study of means for the stabilization of MHD interchange modes in axisymmertric mirror-based plasma confinement systems, is aimed at a preliminary look at a technique that would employ a train of plasma pressure pulses produced by ECRH to accomplish the stabilization. The purpose of using sequentially pulsed ECRH rather than continuous-wave ECRH is to facilitate the localization of the heated-electron plasma pulses in regions of the magnetic field with a strong positive field-line curvature, e. g. in the 'expander' region of the mirror magnetic field, outside the outermost mirror, or in other regions of the field with positive field-line curvature. The technique proposed, of the class known as 'dynamic stabilization,' relies on the time-averaged effect of plasma pressure pulses generated in regions of positive field-line curvature to overcome the destabilizing effect of plasma pressure in regions of negative field-line curvature within the confinement region. As will also be discussed in the paper, the plasma pulses, when produced in regions of the confining having a negative gradient, create transient electric potentials of ambipolar origin, an effect that was studied in 1964 in The PLEIDE experiment in France. These electric fields preserve the localization of the hot-electron plasma pulses for a time determined by ion inertia. It is suggested that it may be possible to use this result of pulsed ECRH not only to help to stabilize the plasma but also to help plug mirror losses in a manner similar to that employed in the Tandem Mirror.

  18. Tandem mirror magnet system for the mirror fusion test facility

    International Nuclear Information System (INIS)

    The Tandem Mirror Fusion Test Facility (MFTF-B) will be a large magnetic fusion experimental facility containing 22 supercounducting magnets including solenoids and C-coils. State-of-the-art technology will be used extensively to complete this facility before 1985. Niobium titanium superconductor and stainless steel structural cases will be the principle materials of construction. Cooling will be pool boiling and thermosiphon flow of 4.5 K liquid helium. Combined weight of the magnets will be over 1500 tonnes and the stored energy will be over 1600 MJ. Magnetic field strength in some coils will be more than 8 T. Detail design of the magnet system will begin early 1981. Basic requirements and conceptual design are disclosed in this paper

  19. Tandem mirror magnet system for the mirror fusion test facility

    Energy Technology Data Exchange (ETDEWEB)

    Bulmer, R.H.; Van Sant, J.H.

    1980-10-14

    The Tandem Mirror Fusion Test Facility (MFTF-B) will be a large magnetic fusion experimental facility containing 22 supercounducting magnets including solenoids and C-coils. State-of-the-art technology will be used extensively to complete this facility before 1985. Niobium titanium superconductor and stainless steel structural cases will be the principle materials of construction. Cooling will be pool boiling and thermosiphon flow of 4.5 K liquid helium. Combined weight of the magnets will be over 1500 tonnes and the stored energy will be over 1600 MJ. Magnetic field strength in some coils will be more than 8 T. Detail design of the magnet system will begin early 1981. Basic requirements and conceptual design are disclosed in this paper.

  20. Catalyzed deuterium fueled tandem mirror reactor assessment

    International Nuclear Information System (INIS)

    This study was part of a Department of Energy supported alternate fusion fuels program at Science Applications International Corp. The purpose of this portion of the study is to perform an assessment of a conceptual tandem mirror reactor (TMR) that is fueled by the catalyzed-deuterium (Cat-d) fuel cycle with respect to the physics, technology, safety, and cost. Achievable stable betas and magnet configurations are found to be comparable for the Cat-d and d-t fueled TMR. A comparison with respect to cost, reactor performance, and technology requirements for a Cat-d fueled reactor and a comparable d-t fueled reactor such as MARS is also made

  1. Vacuum system for the Tandem Mirror Experiment

    International Nuclear Information System (INIS)

    This paper is a sequel to the one prepared by Atkinson, et al., in which the authors described the vacuum system of Lawrence Livermore Laboratory's Tandem Mirror Experiment (TMX). We discuss here the final configuration, liquid nitrogen (LN2) supply, and operation of the complete TMX vacuum system. The assembled vacuum system consists of two plug tanks with a volume of approximately 60 m3 each and a center cell tank with a volume of approximately 10 m3. In each plug tank there are 145 m2 of titanium-gettered, LN2-filled panels, which allow a pumping speed calculated to be 5 x 107 l/s for a period of 50 ms. The system maintains an operating pressure in the plasma chamber on the order of 10-6 Torr while 24 neutral-beam injectors are introducing 700 Torr l/s of hydrogen into the vacuum chamber

  2. Status of tandem-mirror confinement

    International Nuclear Information System (INIS)

    Recent end-stopping experiments in TMX-Upgrade show strong plugging of the central cell by lower-density plugs, requiring both electron-cyclotron heating (ECRH) and 470 neutral-beam injection, consistent with the thermal-barrier concept. These experiments have low density (n 12 cm-3) due to inefficient ECRH power coupling. Hot-ion and hot-electron buildup are consistent with Fokker-Planck calculations. No ion-cyclotron activity is observed in the plugs; occasional electron-cyclotron activity is observed. With plugging, axial lifetimes (tau/sub parallel/ > 40 ms) are larger than radial (tau/sub perpendicular/ = 5 to 10 ms) due to observed non-ambipolar ion transport. Recent tandem-mirror theoretical activities are also surveyed

  3. Preliminary design of a tandem mirror reactor

    International Nuclear Information System (INIS)

    The purpose of this thesis is to examine the TARA mirror experiment as a possible tandem mirror reactor configuration. This is a preliminary study to size the coil structure based on using the smallest end cell axial length that physics and engineering allow, zeroing the central cell parallel currents and having interchange stability. The input powers are estimated for the final reactor design so a Q value may be estimated. The Q value is defined as the fusion power divided by the total injected power absorbed by the plasma. A computer study was performed on the effect of the transition size, the transition vertical spacing and transition current. These parameters affect the central cell parallel currents, the recircularization of the flux tube and the ratio of central cell beta to anchor beta needed for marginal stability. Two designs were identified. The first uses 100 keV and 13 keV neutral beams to pump the ions that trap in the thermal barrier. The Q value of this reactor is 11.3. The second reactor uses a pump beam at 40 keV. This energy is chosen because there is a resonance for the charge exchange cross section between D0 and He2+ at this energy, thus the alpha ash will be pumped along with the deuterium and tritium. The Q value of this reactor is 11.6

  4. Charge exchange cooling in the tandem mirror plasma confinement apparatus

    International Nuclear Information System (INIS)

    A method and apparatus are described for cooling a plasma confined in the center mirror cell of the tandem mirror apparatus by injecting cold neutral species of the plasma into at least one mirroring region of the center mirror cell. The cooling is due to the loss of warm charged species through charge exchange with the cold neutral species with resulting diffusion of the warm neutral species out of the plasma

  5. From x-ray telescopes to neutron scattering: Using axisymmetric mirrors to focus a neutron beam

    Energy Technology Data Exchange (ETDEWEB)

    Khaykovich, B., E-mail: bkh@mit.ed [Nuclear Reactor Laboratory, Massachusetts Institute of Technology, 138 Albany Street, Cambridge, MA 02139 (United States); Gubarev, M.V. [Marshall Space Flight Center, NASA, VP62, Huntsville, AL 35812 (United States); Bagdasarova, Y. [Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Ramsey, B.D. [Marshall Space Flight Center, NASA, VP62, Huntsville, AL 35812 (United States); Moncton, D.E. [Nuclear Reactor Laboratory, Massachusetts Institute of Technology, 138 Albany Street, Cambridge, MA 02139 (United States); Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)

    2011-03-01

    We demonstrate neutron beam focusing by axisymmetric mirror systems based on a pair of mirrors consisting of a confocal ellipsoid and hyperboloid. Such a system, known as a Wolter mirror configuration, is commonly used in X-ray telescopes. The axisymmetric Wolter geometry allows nesting of several mirror pairs to increase collection efficiency. We implemented a system containing four nested Ni mirror pairs, which was tested by the focusing of a polychromatic neutron beam at the MIT Reactor. In addition, we have carried out extensive ray-tracing simulations of the mirrors and their performance in different situations. The major advantages of the Wolter mirrors are nesting for large angular collection and aberration-free performance. We discuss how these advantages can be utilized to benefit various neutron scattering methods, such as imaging, SANS, and time-of-flight spectroscopy.

  6. From x-ray telescopes to neutron scattering: Using axisymmetric mirrors to focus a neutron beam

    International Nuclear Information System (INIS)

    We demonstrate neutron beam focusing by axisymmetric mirror systems based on a pair of mirrors consisting of a confocal ellipsoid and hyperboloid. Such a system, known as a Wolter mirror configuration, is commonly used in X-ray telescopes. The axisymmetric Wolter geometry allows nesting of several mirror pairs to increase collection efficiency. We implemented a system containing four nested Ni mirror pairs, which was tested by the focusing of a polychromatic neutron beam at the MIT Reactor. In addition, we have carried out extensive ray-tracing simulations of the mirrors and their performance in different situations. The major advantages of the Wolter mirrors are nesting for large angular collection and aberration-free performance. We discuss how these advantages can be utilized to benefit various neutron scattering methods, such as imaging, SANS, and time-of-flight spectroscopy.

  7. Results from the Tara tandem mirror experiment

    International Nuclear Information System (INIS)

    A summary of the experimental results from the Tara tandem mirror experiment is presented. Optimization of the fueling configuration, slow wave ion cyclotron heating from a magnetic ''plateau'' using an aperture antenna design, and enhanced stabilization from a magnetic divertor have allowed the attainment of a stable start up plasma (T/sub i,perpendicular/ = 800 - 1500 eV, n/sub e/ = 4 - 5 x 1012 cm-3, T/sub e/ = 70 - 80 eV). Plugging experiments using radiofrequency waves near the plug midplane ion cyclotron frequency have proved successful in reducing endloss, while simultaneously leading to an increase in central cell density. The plugging potentials have been limited to approximately the ion parallel temperature. This limitation is due to low frequency instabilities localized in the plug. Axial plugging experiments using electron cyclotron (ECH) resonant microwave radiation in the plug cells have had ambiguous results. Endloss reductions up to 100% have been achieved without build-up of central cell densities or the appearance of the reflected particles at the other end of the machine. We conjecture that rapid radial losses accompany the use of ECH, although the mechanisms for this loss remain unidentified. 9 refs., 9 figs

  8. Characteristics of hot ions with a strong RF heating in the gamma 10 tandem mirror

    International Nuclear Information System (INIS)

    Radio frequency waves in the ion cyclotron range of frequency (ICRF) are mainly used for the plasma production and heating in the central cell of the GAMMA 10 tandem mirror. The GAMMA 10 has minimum-B anchor cells with a non-axisymmetric magnetic field configuration. The ICRF heating system in the central cell has been improved to create a more axisymmetric plasma. A high ion temperature is attained with the system and high energy ions more than 50 keV are detected in both parallel and perpendicular directions to the magnetic field line. Strong temperature anisotropy is observed and strong Alfven ion cyclotron (AIC) modes are excited due to the anisotropy. With the AIC modes, high energy ions detected at the end increase and high energy ions with nearly 90 degrees pitch angle in the central cell decrease. (author)

  9. A tandem mirror hybrid plume plasma propulsion facility

    Science.gov (United States)

    Yang, T. F.; Krueger, W. A.; Peng, S.; Urbahn, J.; Chang-Diaz, F. R.

    1988-01-01

    This paper discusses a novel concept in electrodeless plasma propulsion, in which the materials problems are ameliorated by an electrodeless magnetic confinement scheme borrowed from the tandem mirror approach to controlled thermonuclear fusion. The concept also features a two-stage magnetic nozzle with an annular hypersonic coaxial gas injector near the throat. The nozzle produces hybrid plume by the coaxial injection of hypersonic neutral gas, and the gas layer thus formed protects the material walls from the hot plasma and, through increased collisions, helps detach it from the diverging magnetic field. The tandem mirror plasma propulsion facility is capable of delivering a variable I(sp). The results of numerical simulation of this concept are presented together with those from an experimental tandem-mirror plasma propulsion device.

  10. Comparative end-plug study for tandem mirror reactors

    International Nuclear Information System (INIS)

    A comparative evaluation was made of several end plug configurations for tandem mirror fusion reactors with thermal barriers. The axicell configuration has been selected for further study and will be the basis for a detailed conceptual design study to be carried out over the next two years. The axicell end plug has a simple mirror cell produced by two circular coils followed by a transition coil and a yin-yang pair, which provides for MHD stability

  11. Interim report on the tandem mirror hybrid design study

    International Nuclear Information System (INIS)

    The initial phase of a 2-year design study of a tandem mirror fusion reactor is presented. The following chapters are included: (1) mechanical design of the plant; (2) plasma physics; (3) blanket design; (4) magnet design; (5) injector design; (6) direct convertor design; (7) balance of plant design; (8) fission burner reactor; (9) environment and safety; and (10) economic analysis

  12. Interim report on the tandem mirror hybrid design study

    Energy Technology Data Exchange (ETDEWEB)

    Moir, R.W. (ed.)

    1979-08-01

    The initial phase of a 2-year design study of a tandem mirror fusion reactor is presented. The following chapters are included: (1) mechanical design of the plant; (2) plasma physics; (3) blanket design; (4) magnet design; (5) injector design; (6) direct convertor design; (7) balance of plant design; (8) fission burner reactor; (9) environment and safety; and (10) economic analysis. (MOW)

  13. Impurity diagnostics in the GAMMA 10 tandem mirror

    International Nuclear Information System (INIS)

    We have constructed spectroscopic measurement systems in the wavelength range from soft X-ray to visible lights. We observed absolute impurity line intensities, Doppler line broadenings and Doppler shifts of impurity lines and time dependent radial profiles of the impurity lines in the GAMMA 10 tandem mirror. (author)

  14. Stochastic motion of particles in tandem mirror devices

    International Nuclear Information System (INIS)

    Stochastic motion of particles in tandem mirror devices is examined on basis of a nonlinear mapping of particle positions on the equatorial plane. Local stability analysis provides detailed informations on particle trajectories. The rate of stochastic plasma diffusion is estimated from numerical observations of motions of particles over a large number of time steps. (author)

  15. Trapped Particle Instability in Kinetic Stabilized Tandem Mirror

    Science.gov (United States)

    Berk, Herbert; Pratt, Jane

    2009-11-01

    The kinetic stabilizer tandem mirror (KSTM) devised by R. F. Post (J. Fus. Energy 2007) is an innovative concept devised to stabilize a symmetric tandem mirror machines using a concept devised by D. Ryutov (Proc. of Course and Workshop, Varenna, Italy, 1987) and empirically verified in the Gas Dynamic Trap (Ivanov, et. al. Trans. Fusion Technology 39, 127, 2001). The KSTM uses the momentum flux of unconfined particles that only sample the outer end regions of the mirror where there is very favorable field line curvature. Charged ion beams at relatively low energy are externally injected into the ends and reflected out from the ends. MHD stability with a power drain less than the fusion power production can be achieved. We examine the effect of fast growing trapped particle instability (Berk et. al. Sov J. Plasma Phys. 1983) on the overall stability. In this case stability is very sensitive to the electron connection between the stabilizer and end plug.

  16. Emission spectroscopy of ECRH non-axisymmetric helium mirror plasmas

    International Nuclear Information System (INIS)

    In this experiment emission spectroscopy in the 3000 to 5000 Angstrom range has been utilized to determine the electron temperature of helium plasmas produced by the Michigan Mirror Machine (MIMI). The plasma is generated and heated by whistler-mode electron-cyclotron resonance waves at 7.43 GHz and 500 Watts power in 400 μs pulses. Gas is puffed into the mid-plane region where a quartz window is used to observe the plasma. The plasma is viewed in a direction perpendicular to the mirror axis

  17. The ''Kinetic Stabilizer'': A Simpler Tandem Mirror Confinement?

    Energy Technology Data Exchange (ETDEWEB)

    Post, R.F.

    2000-06-15

    ;'stabilizer plasma'' outside a mirror, will be discussed. To create this plasma ion beams are injected along the field lines in such a way as to be reflected before they reach the mirrors, thus forming a localized peak in the plasma density. It will be shown that the power required to produce these stabilizing plasmas is much less than the power per meter of fusion power systems that might employ this technique. Use of the Kinetic Stabilizer idea may therefore permit the construction of tandem mirror fusion power systems that are much smaller and simpler than those based on the use of non-axisymmetric fields to achieve MHD stability.

  18. Summary of results from the Tandem Mirror Experiment (TMX)

    International Nuclear Information System (INIS)

    This report summarizes results from the successful experimental operation of the Tandem Mirror Experiment (TMX) over the period October 1978 through September 1980. The experimental program, summarized by the DOE milestones given in Table 1-1, had three basic phases: (1) an 8-month checkout period, October 1978 through May 1979; (2) a 6-month initial period of operation, June through November 1979, during which the basic principles of the tandem configuration were demonstrated (i.e., plasma confinement was improved over that of a single-cell mirror); and (3) a 10-month period, December 1979 through September 1980, during which the initial TMX results were corroborated by additional diagnostic measurements and many detailed physics investigations were carried out. This report summarizes the early results, presents results of recent data analysis, and outlines areas of ongoing research and data analysis which will be reported in future journal publications

  19. TMX-U Tandem-Mirror thermal-barrier experiments

    International Nuclear Information System (INIS)

    Thermal-barrier experiments have been carried out in the Tandem Mirror Experiment-Upgrade (TMX-U). Measurements of nonambipolar and ambipolar radial transport show that these transport processes, as well as end losses, can be controlled at modest densities and durations. Central-cell heating methods using ion-cyclotron heating (ICH) and neutral-beam injection have been demonstrated. Potential measurements with recently developed methods indicate that deep thermal barriers can be established

  20. Neutral beam control systems for the Tandem Mirror Experiment

    International Nuclear Information System (INIS)

    The Tandem Mirror Experiment (TMX) is presently developing the technology and approaches which will be used in larger fusion systems. This paper describes some of the designs which were used in creating the control system for the TMX neutral beams. To create a system of controls that would work near these large, rapid switching current sources required a mixture of different technologies: fiberoptic data transmission, printed circuit and wirewrap techniques, etc

  1. Time-of-flight potential diagnostics for tandem mirrors

    International Nuclear Information System (INIS)

    Two time-of-flight potential diagnostics for tandem mirrors are investigated. These diagnostics are designed to measure axial potential variations in tandem-mirror plasma geometries. One approach investigated employs an electron beam as a potential probe, and the other employs a helium ion beam. In each case, a modulated beam is injected along the magnetic axis of the magnetic field into the plasma confinement region. The velocity of the beam particles varies as the beam moves through variations in the electrostatic potential. Since the beam is modulated, variations in beam velocity modify the modulation phase of the beam along the beam trajectory. In the case of the electron beam, the phase of the beam is remotely detected by using a Rogowski loop that encircles the plasma. The phase of the helium ion beam can be measured by observing the light emitted by the helium ions. A theoretical study was made regarding the feasibility of the modulated ion beam concept for measuring potentials in the TMX-U and MFTF-B tandem mirrors machines at the Lawrence Livermore National Laboratory. The estimated potential uncertainties for these machines appear quite small, provided an ion beam of the required quality can be modulated at a high enough frequency. In order to address this concern, a 5-k-V, 10-mA ion beam was designed, fabricated, and tested

  2. Preliminary design of a Tandem-Mirror-Next-Step facility

    International Nuclear Information System (INIS)

    The Tandem-Mirror-Next-Step (TMNS) facility is designed to demonstrate the engineering feasibility of a tandem-mirror reactor. The facility is based on a deuterium-tritium (D-T) burning, tandem-mirror device with a fusion power output of 245 MW. The fusion power density in the central cell is 2.1 MW/m3, with a resultant neutron wall loading of 0.5 MW/m2. Overall machine length is 116 m, and the effective central-cell length is 50.9 m. The magnet system includes end cells with yin-yang magnets to provide magnetohydrodynamic (MHD) stability and thermal-barrier cells to help achieve a plasma Q of 4.7 (where Q = fusion power/injected power). Neutral beams at energies up to 200 keV are used for plasma heating, fueling, and barrier pumping. Electron cyclotron resonant heating at 50 and 100 GHz is used to control the electron temperature in the barriers. Based on the resulting engineering design, the overall cost of the facility is estimated to be just under $1 billion. Unresolved physics issues include central-cell β-limits against MHD ballooning modes (the assumed reference value of β exceeds the current theory-derived limit), and the removal of thermalized α-particles from the plasma

  3. Efficient trap of a coaxial gun plasma in an axisymmetric mirror with an internal hoop

    International Nuclear Information System (INIS)

    A method to trap a high temperature and high density plasma from a coaxial gun in a mirror machine is described. The method is to inject plasma parallel to the axis from a coaxial gun located off the axis. The validity of the method is experimentally demonstrated with an MHD-stabilized axisymmetric mirror with an internal hoop. Density, electron and ion temperatures and their time behaviors were measured and it was made clear that a high density high temperature plasma was well trapped in the mirror by the parallel off-axis injection while the plasma was little trapped by on-axis injection. The plasma parameters obtained were also compared with those of a conventional titanium washer gun plasma. The causes to restrict the maximum ion temperature and of its quick decay are discussed. (author)

  4. Magnetic ripple correction in tandem mirrors by ferromagnetic inserts

    International Nuclear Information System (INIS)

    Magnetic ripple of 1% or more caused by discrete solenoid coils in the central cells of tandem mirrors may severely affect the MHD stability. The ripple amplitude can be reduced by an order of magnitude by ferromagnetic annuli inserted within the coils at the regions of ripple maxima. The inserts need not affect the accessibility, coil diameter, or capital cost, since large quantities of steel are required within the coils for the neutron blanket and shield. Design of the ripple correction is simplified and linearized by the cylindrical geometry and by the saturation of the ferromagnetic steel

  5. Configuration and layout of the tandem mirror Fusion Power Demonstrator

    International Nuclear Information System (INIS)

    Studies have been performed during the past year to determine the configuration of a tandem mirror Fusion Power Demonstrator (FPD) machine capable of producing 1750 MW of fusion power. The FPD is seen as the next logical step after the Mirror Fusion Test Facility-B (MFTF-B) toward operation of a power reactor. The design of the FPD machine allows a phased construction: Phase I, a hydrogen or deuterium checkout machine; Phase 2, a DT breakeven machine; Phase 3, development of the Phase 2 machine to provide net power and act as a reactor demonstrator. These phases are essential to the development of remote handling equipment and the design of components that will ultimately be remotely handled. Phasing also permits more modes funding early in the program with some costs committed only after reaching major milestones

  6. Orbit averaged radial buildup code for tandem mirror geometry

    International Nuclear Information System (INIS)

    The radial Fokker-Planck (RFP) model of A. Futch was modified to treat plasma buildup in the tandem mirror plug and center cell with a self-consistent model (TOARBUC). Two major changes have been made to the original version of this code. First, the center cell is treated as having separate electron and ion confining potentials with the ion potential having the opposite sign of that in a conventional mirror. Second, a two-electron-temperature treatment derived by R. Cohen was included in the present model to allow the plug and center cell to have different T/sub e/'s as observed in the experiment. The following sections explain these changes in greater detail

  7. Investigation of barrier cell and auxilliary heating in a tandem mirror. Annual progress report, October 1, 1979-September 30, 1980

    International Nuclear Information System (INIS)

    A number of areas relating to RF heating and thermal barrier formation in a tandem mirror have been investigated. The possibility of creating axisymmetric confinement through the use of sloshing-ions has been investigated. We have also suggested the complimentary concept of sloshing-electrons. Self-consistent thermal barrier formation has been studied and ion drift orbits in non-axisymmetric barriers are being investigated. The study of dynamic stabilization of the DCLC by RF fields has been extended to ω near 2 ω/sub ci/; significant stabilization is found. Fast and slow wave heating have been extensively studied using single particle theory. A new theory of relativistic ECH is under development

  8. Mechanical design aspects of a tandem mirror fusion reactor

    Energy Technology Data Exchange (ETDEWEB)

    Neef, W.S. Jr.

    1977-04-25

    Two ''plugs'' of dense plasma at either end of a central solenoid cell form the basis of a new mirror fusion power plant concept. A central cell blanket design is presented. Modules on crawler tracks serviced by remote welding and handling machines of very simple design are important features resulting from linear axisymmetric geometry. Three blanket designs are considered and the best one presented in some detail. It has lithium as the breeder material, helium cooled. ''Plug'' magnet field strengths must be high. A novel magnet is presented to satisfy the physics of the end plugs. Beam sources at 1,200 KV present special problems. Methods of voltage standoff, arc damage control, and neutralization are discussed. New secondary containment ideas are presented to allow removable roof sections of balanced design.

  9. Mechanical design aspects of a tandem mirror fusion reactor

    International Nuclear Information System (INIS)

    Two ''plugs'' of dense plasma at either end of a central solenoid cell form the basis of a new mirror fusion power plant concept. A central cell blanket design is presented. Modules on crawler tracks serviced by remote welding and handling machines of very simple design are important features resulting from linear axisymmetric geometry. Three blanket designs are considered and the best one presented in some detail. It has lithium as the breeder material, helium cooled. ''Plug'' magnet field strengths must be high. A novel magnet is presented to satisfy the physics of the end plugs. Beam sources at 1,200 KV present special problems. Methods of voltage standoff, arc damage control, and neutralization are discussed. New secondary containment ideas are presented to allow removable roof sections of balanced design

  10. Trapped Particle Instabilities in the Kinetically Stabilized Tandem Mirror

    Science.gov (United States)

    Pratt, J.; Berk, H. L.; Horton, W.

    2009-05-01

    The kinetically stabilized tandem mirror (KSTM) is an innovative design to stabilize MHD modes in an axially symmetric tandem mirror machine (Post, J. Fus. Energy 2007). Originally proposed by Ryutov (Ryutov, Proc. of Course and Workshop, Varenna, Italy, 1987), this stabilizer has been empirically verified in the Gas Dynamic Trap (Ivanov, Anakeev et.al. Trans. Fusion Technology. 39, 127, 2001). The KSTM uses the momentum flux of escaping particles that sample good magnetic-field-line-curvature region outside the central confinement region. Charged ion beams at relatively low energy are externally injected from the ends into the expander region at an energy that is consistent with a stable MHD prediction and acceptable power loss for fusion. If stable, the KSTM would be extremely useful for limiting radial diffusion since the chaotic step size is minimized. We confirm that MHD stability is achieved in the KSTM. We examine the effect of the trapped particle instability discussed in Berk, Rosenbluth, et al. Sov. J. Plasma Phys. 1983 on overall stability. In this case stability is very sensitive to the electron connection between the stabilizer and the end plug.

  11. SOFTWARE-CONTROLLED SYSTEM OF ULTRA-PRECISION MACHINING AXISYMMETRIC ASPHERIC MIRROR

    Institute of Scientific and Technical Information of China (English)

    GUO Yinbiao; WEI Lizhen

    2006-01-01

    In order to improve machining accuracy and efficiency, a software-controlled system of ultra-precision machining for axisymmetric aspheric mirror, using techniques of error compensation,remote transmission and modularization, is designed based on industrial PC, Windows 2000 work platform and Visual Basic 6.0. By experiments, this system realizes functions of ultra-precision machining, machining error compensation, remote data transmission and automatic data transformation among first machining, compensation machining and accuracy measurement. The actual application shows that error compensation improves machining accuracy, remote transmission improves machining efficiency while modularization avoids repeated work and improves design efficiency. Therefore, the system has met ultra-precision machining need for aspheric mirror.

  12. Studies in tandem mirror theory. Paper IAEA-CN-38/F-4

    International Nuclear Information System (INIS)

    This paper discusses the formation, maintenance, and microstability of thermal barriers, which have been introduced as a means for improving tandem mirror reactor performance at reduced technological demands. It also describes calculations of tandem mirror central-cell β limits due to MHD ballooning modes

  13. Calculation of density profiles in tandem mirrors fueled by pellets

    International Nuclear Information System (INIS)

    We have modified the LLNL radial transport code TMT to model reactor regime plasmas, fueled by pellets. The source profiles arising from pellet fueling are obtained from existing pellet ablation models. Because inward radial diffusion due to inverted profiles must compete with trapping of central cell ions in the transition region for tandem mirrors, pellets must penetrate fairly far into the plasma. In fact, based on our radial calculations, a pellet with a velocity of 10 km/sec cannot sustain the central flux tubes; a velocity more like 100 km/sec will be necessary. We also find that the central cell radial diffusion must exceed classical by about a factor of 100

  14. Physics-magnetics trade studies for tandem mirror reactors

    International Nuclear Information System (INIS)

    We describe and present results obtained from the optimization package of the Tandem Mirror Reactor Systems Code. We have found it to be very useful in searching through multidimensional parameter space, and have applied it here to study the effect of choke coil field strength and net electric power on cost of electricity (COE) and mass utilization factor (MUF) for MINIMARS type reactors. We have found that a broad optimum occurs at B/sub choke/ = 26 T for both COE and MUF. The COE economy of scale approaches saturation at quite low powers, around 600 MW(e). The saturation is mainly due to longer construction times for large plants, and the associated time related costs. The MUF economy of scale does not saturate, at least for powers up to 2400 MW(e)

  15. Gas box control system for Tandem Mirror Experiment-Upgrade

    International Nuclear Information System (INIS)

    The Tandem Mirror Experiment-Upgrade (TMX-U) uses several methods to feed gas (usually deuterium) at different energies into the plasma region of the machine. One is an arrangement of eight high-speed piezo-electric valves mounted on special manifolds (gas box) that feed cold gas directly to the plasma. This paper describes the electronic valve control and data acquisition portions of the gas box, which are controlled by a desk-top computer. Various flow profiles have been developed and stored in the control computer for ready access by the operator. The system uses two modes of operation, one that exercises and characterizes the valves and one that operates the valves with the rest of the experiment. Both the valve control signals and the pressure transducers data are recorded on the diagnostics computer so that they are available for experiment analysis

  16. Vacuum vessel for the tandem Mirror Fusion Test Facility

    International Nuclear Information System (INIS)

    In 1980, the US Department of Energy gave the Lawrence Livermore National Laboratory approval to design and build a tandem Mirror Fusion Test Facility (MFTF-B) to support the goals of the National Mirror Program. We designed the MFTF-B vacuum vessel both to maintain the required ultrahigh vacuum environment and to structurally support the 42 superconducting magnets plus auxiliary internal and external equipment. During our design work, we made extensive use of both simple and complex computer models to arrive at a cost-effective final configuration. As part of this work, we conducted a unique dynamic analysis to study the interaction of the 32,000-tonne concrete-shielding vault with the 2850-tonne vacuum vessel system. To maintain a vacuum of 2 x 10-8 torr during the physics experiments inside the vessel, we designed a vacuum pumping system of enormous capacity. The vacuum vessel (4200-m3 internal volume) has been fabricated and erected, and acceptance tests have been completed at the Livermore site. The rest of the machine has been assembled, and individual systems have been successfully checked. On October 1, 1985, we began a series of integrated engineering tests to verify the operation of all components as a complete system

  17. Safety assessment of the MARS tandem mirror reactor

    International Nuclear Information System (INIS)

    The safety of the Mirror Advanced Reactor Study (MARS) tandem mirror reactor is assessed. Only prompt consequences to the public at the plant boundary, which is taken to be 1000m, are considered. The major radioactive inventories in MARS reside in the first-wall/blanket structure, coolant, and tritium. The greatest radioactivity resides in the HT-9 first-wall/ blanket structure. The only accident scenario identified that could lead to a first-wall meltdown was a loss-of-coolant accident (LOCA) accompanied by the inability to shut off the plasma. However, since only oxides of molybdenum are expected to be volatized from the hot HT-9 structure, the public consequences are found to be low. A LOCA can result in large doses if the activity in the activated corrosion products and LiPb coolant can be transported outside the reactor containment building. However, most of the LiPb would be expected to solidify, and any aerosols that are produced will likely plate out on surfaces or settle. Various tritium accident scenarios were considered. Release of all the tritium in the reactor building (51 g) leads to a dose of 21 rem. A much more likely accident involves partial leakage due to some reactor containment damage

  18. Synfuels from fusion: producing hydrogen with the Tandem Mirror Reactor and thermochemical cycles

    International Nuclear Information System (INIS)

    This volume contains the following sections: (1) the Tandem Mirror fusion driver, (2) the Cauldron blanket module, (3) the flowing microsphere, (4) coupling the reactor to the process, (5) the thermochemical cycles, and (6) chemical reactors and process units

  19. TMX-U [Tandem Mirror Experiment-Upgrade]: Final report, Volume 1

    International Nuclear Information System (INIS)

    This paper discusses the plasma control and the physics accomplishments of the Tandem Mirror Experiment-Upgrade. This particular volume discusses potential measurements, plasma confinement, and hot electron and ion physics. 230 refs

  20. Synfuels from fusion: producing hydrogen with the Tandem Mirror Reactor and thermochemical cycles

    Energy Technology Data Exchange (ETDEWEB)

    Werner, R.W.; Ribe, F.L.

    1981-01-21

    This volume contains the following sections: (1) the Tandem Mirror fusion driver, (2) the Cauldron blanket module, (3) the flowing microsphere, (4) coupling the reactor to the process, (5) the thermochemical cycles, and (6) chemical reactors and process units. (MOW)

  1. TMX-U [Tandem Mirror Experiment-Upgrade]: Final report, Volume 2

    International Nuclear Information System (INIS)

    This paper discusses the plasma control and the physics accomplishments of the Tandem Mirror Experiment-Upgrade. This particular volume discusses fueling, ion heating, Fokker-Planck modeling, plasma stability and technical development. 270 refs

  2. Mechanical design of the Tandem Mirror Experiment Upgrade vacuum system

    International Nuclear Information System (INIS)

    The Tandem Mirror Experiment Upgrade (TMX Upgrade) vacuum system uses most of the vacuum system from the original TMX and substantially increases its capabilities. The vacuum system provides the main structure for the experimental apparatus, as well as providing and maintaining the vacuum environment. The vacuum vessel provides the structure supporting all magnets, as they are contained inside the vacuum vessel, all of the neutral-beam injectors, and the various diagnostics. The vessel provides the main vacuum enclosure and the various access ports required by the magnet system, injector system, internal vacuum system, and plasma diagnostics. The vacuum environment is created and maintained by two systems, the external vacuum system and the internal vacuum system. The external system consists of mechanical pumps, turbopumps, and cryopumps, and creates a vacuum inside the vessel down to a minimum pressure of 10-6 Torr. The internal vacuum system further reduces the pressure into the 10-8 Torr range and provides the fast pumping required to handle the excess gas from the neutral-beam injector system during a plasma shot. The internal vacuum system consists of titanium sublimators and liquid nitrogen (LN) liners that separate the vacuum vessel into various pumping regions

  3. Mechanical design of the Tandem Mirror Experiment Upgrade vacuum system

    Energy Technology Data Exchange (ETDEWEB)

    Lang, D.D.; Calderon, M.O.; Thomas, S.R.; Garner, D.R.

    1981-09-24

    The Tandem Mirror Experiment Upgrade (TMX Upgrade) vacuum system uses most of the vacuum system from the original TMX and substantially increases its capabilities. The vacuum system provides the main structure for the experimental apparatus, as well as providing and maintaining the vacuum environment. The vacuum vessel provides the structure supporting all magnets, as they are contained inside the vacuum vessel, all of the neutral-beam injectors, and the various diagnostics. The vessel provides the main vacuum enclosure and the various access ports required by the magnet system, injector system, internal vacuum system, and plasma diagnostics. The vacuum environment is created and maintained by two systems, the external vacuum system and the internal vacuum system. The external system consists of mechanical pumps, turbopumps, and cryopumps, and creates a vacuum inside the vessel down to a minimum pressure of 10/sup -6/ Torr. The internal vacuum system further reduces the pressure into the 10/sup -8/ Torr range and provides the fast pumping required to handle the excess gas from the neutral-beam injector system during a plasma shot. The internal vacuum system consists of titanium sublimators and liquid nitrogen (LN) liners that separate the vacuum vessel into various pumping regions.

  4. TMRBAR power balance code for tandem mirror reactors

    International Nuclear Information System (INIS)

    A revised version of the tandem mirror multi-point code TMRBAR developed at LLNL has been used to examine various reactor designs using MARS-like ''c'' coils. We solve 14 to 16 non-linear equations to obtain the densities, temperatures, plasma potential and magnetic field on axis at the cardinal points. Since ICRH, ECRH, and neutral beams may be used to stabilize the central cell, various combinations of rf and neutral beam powers may satisfy the physics. To select a desired set of physics parameters, we use nonlinear optimization techniques. Whit these routines, we minimize or maximize a physics variable subject to the physics constraints being satisfied. For example, for a given fusion power we may find the minimum length needed to have an ignited central cell or the maximum fusion Q. Finally, we have coupled this physics model to the LLNL magnetics-MHD code. This code runs the EFFI magnetic field generator and uses TEBASCO to calculate 1-D MHD equilibria and stability

  5. Model for ion confinement in a hot-electron tandem mirror anchor

    International Nuclear Information System (INIS)

    Anisotropic, hot electrons trapped in local minimum-B wells have been proposed as MHD-stabilizing anchors to an otherwise axisymmetric tandem configuration. This work describes a model for plasma confinement between the anchors and the remainder of the system and calcuates the power loss implied by maintenance of this plasma

  6. Electron and ion cyclotron heating calculations in the tandem-mirror modeling code MERTH

    International Nuclear Information System (INIS)

    To better understand and predict tandem-mirror experiments, we are building a comprehensive Mirror Equilibrium Radial Transport and Heating (MERTH) code. In this paper we first describe our method for developing the code. Then we report our plans for the installation of physics packages for electron- and ion-cyclotron heating of the plasma

  7. A d-d tandem mirror reactor assessment

    International Nuclear Information System (INIS)

    A conceptual tandem mirror reactor (TMR) that is fueled by the catalyzed-deuterium fuel cycle is assessed with respect to physics, technology, safety, and cost. A comparison with respect to these issues is made between this reactor and a deuterium-tritium fueled TMR similar to that developed for the MARS study. Both designs have ends stoppered by a combination of magnetic and electrostatic fields and fusion takes place within the solenoid. The magnetic field end plugs are formed by a combination of 24 Tesla coils and a system of 8 Tesla yin-yang coils to provide stability. The ambipolar potential electron and ion plugs are formed in the yin-yangs and are created by a combination of neutral beams and electron cyclotron resonance heating (ECRH). Fusion power is converted to electricity in a TMR by two methods: by volumetric heat generation from neutron bombardment in the blanket and by direct conversion of the energy from changed particles escaping from the ends of the TMR. Thermal energy from neutrons is converted more efficiently for a Cat-d TMR because of relative blanket simplicity. Both Cat-d and d-t TMRs can utilize high efficiency direct conversion, but the former has a greater percentage of fusion power in charge particles. The total activation of the first wall and blanket due to neutron bombardment is similar for the Cat-d and d-t TMRs, but the tritium inventory is about three orders of magnitude greater in the latter. It is determined that although the Cat-d TMR operates at a higher ion temperature and is generally larger than a d-t TMR, the first wall and blanket lifetimes are an order of magnitude larger, and the capital costs are comparable for the same net power output

  8. Review of electron-beam heating of magnetic-mirror confined plasmas, with application to the Tandem Mirror Experiment

    International Nuclear Information System (INIS)

    This report reviews results from early electron-beam heating experiments and more recent basic beam-plasma physics experiments as well as present theoretical understanding. We find tha rather simple electron-beams could be employed on the Tandem Mirror Experiment (TMX) at Lawrence Livermore Laboratory to carry out electron heating experiments

  9. Construction and operational experience of the Tandem Mirror Experiment-Upgrade (TMX-U)

    International Nuclear Information System (INIS)

    The Tandem Mirror Experiment-Upgrade (TMX-U) incorporates two new features at Lawrence Livermore National Laboratory (LLNL) tandem mirror program, thermal barriers in the end plugs and injection of the neutral beams at several oblique angles. The thermal barriers isolate the electrons in the end plugs from those in the central cell, making it possible to heat them independently with microwaves. In addition, this innovation produces a large potential gradient in the end plugs with lower magnetic fields and lower neutral-beam energies than would be possible in a conventional tandem mirror device. The TMX-U is also designed to test neutral-beam-injection angles as an experimental parameter. We use angles other than 900 to produce a plasma with improved microstability

  10. Small-scale experimental tests of tandem mirror machines with thermal barriers

    International Nuclear Information System (INIS)

    A summary is given of current physical understanding of tandem mirrors with thermal barriers. Physicists who understand tandem mirrors can use this document as a preliminary guide to the physical issues and experimental problems involved. This report will focus upon the issues that can be tested experimentally, and on the areas needing experimental and theoretical inventions. The next section discusses the plasma potentials and plasma confinement which correspond to a tandem mirror with thermal barriers, assuming the barriers exist in steady-state. The creation of a barrier is discussed, i.e., the natural tendency of the barrier cell to fill with plasma must be countered by pumping ions out of the barrier. The design of a barrier-pumping experiment for TMX is described

  11. Studies of rf tandem mirror heating. Annual progress report, October 1, 1978-September 30, 1979

    International Nuclear Information System (INIS)

    During the first 8 months of this project the questions of primary interest have been centered on the use of Ion Cyclotron Resonance Frequency range (ICRF) wave heating in tandem mirror plugs. In particular we have been engaged in examining the following questions: (1) the use of ICRF to provide partial plug fueling in a tandem mirror, (2) the effect on spatial density and ambipolar potential distribution of the location of the wave-particle resonance zone, (3) dynamic stabilization of the Drift Cyclotron Loss-Cone instability due to the imposed ICRF

  12. Influence of the shear flow on electron cyclotron resonance plasma confinement in an axisymmetric magnetic mirror trap of the electron cyclotron resonance ion source

    International Nuclear Information System (INIS)

    Influence of shear flows of the dense plasma created under conditions of the electron cyclotron resonance (ECR) gas breakdown on the plasma confinement in the axisymmetric mirror trap (''vortex'' confinement) was studied experimentally and theoretically. A limiter with bias potential was set inside the mirror trap for plasma rotation. The limiter construction and the optimal value of the potential were chosen according to the results of the preliminary theoretical analysis. This method of ''vortex'' confinement realization in an axisymmetric mirror trap for non-equilibrium heavy-ion plasmas seems to be promising for creation of ECR multicharged ion sources with high magnetic fields, more than 1 T.

  13. Plasma diagnostic techniques in thermal-barrier tandem-mirror fusion experiments

    Energy Technology Data Exchange (ETDEWEB)

    Silver, E.H.; Clauser, J.F.; Carter, M.R.; Failor, B.H.; Foote, J.H.; Hornady, R.S.; James, R.A.; Lasnier, C.J.; Perkins, D.E.

    1986-08-29

    We review two classes of plasma diagnostic techniques used in thermal-barrier tandem-mirror fusion experiments. The emphasis of the first class is to study mirror-trapped electrons at the thermal-barrier location. The focus of the second class is to measure the spatial and temporal behavior of the plasma space potential at various axial locations. The design and operation of the instruments in these two categories are discussed and data that are representative of their performance is presented.

  14. Plasma diagnostic techniques in thermal-barrier tandem-mirror fusion experiments

    International Nuclear Information System (INIS)

    We review two classes of plasma diagnostic techniques used in thermal-barrier tandem-mirror fusion experiments. The emphasis of the first class is to study mirror-trapped electrons at the thermal-barrier location. The focus of the second class is to measure the spatial and temporal behavior of the plasma space potential at various axial locations. The design and operation of the instruments in these two categories are discussed and data that are representative of their performance is presented

  15. Design for the magnetic field requirements of the tandem mirror experiment

    International Nuclear Information System (INIS)

    The tandem mirror magnetic geometry is described, followed by an analysis of the magnet set designed to meet the requirements of the TMX experiment. The final magnet line-up is composed of a baseball coil with two C coils for each plug, six solenoidal coils for the central cell, and two RC coils plus one octupole coil for each transition

  16. Monte Carlo particle simulation and finite-element techniques for tandem mirror transport

    International Nuclear Information System (INIS)

    A description is given of numerical methods used in the study of axial transport in tandem mirrors owing to Coulomb collisions and rf diffusion. The methods are Monte Carlo particle simulations and direct solution to the Fokker-Planck equations by finite-element expansion. (author)

  17. Focusing twist reflector for electron-cyclotron resonance heating in the Tandem Mirror Experiment-Upgrade

    International Nuclear Information System (INIS)

    A twist reflector plate is described that linearly polarizes and focuses the TE/sub O1/ circular waveguide mode for heating hot electrons in the thermal barrier of the Tandem Mirror Experiment-Upgrade (TMX-U). The plate polarizing efficiency is 95%, and it has operated satisfactorily at 150 kW power level

  18. Design of an 18 Tesla, tandem mirror, fusion reactor, hybrid choke coil

    International Nuclear Information System (INIS)

    A hybrid, part normal part superconducting 18-Tesla solenoid choke coil is designed for a tandem mirror fusion reactor. The present state of the art is represented by the 12-Tesla, superconducting NbSn coil. Future applications other than tandem mirror fusion devices needing high field solenoids might require hybrid magnets of the type described herein. The hybrid design was generated because of critical field performance limitations on present, practical superconducting wires. A hybrid design might be required (due to structural limits) even if the critical field were higher. Also, hybrids could be a cost-effective way of getting very high fields for certain applications. The 18-Tesla solenoid described is composed of an inner coil made of water-cooled, high-strength zirconium copper which generates 3 Tesla. A superconducting NbSn background coil contributes the remaining 15 Tesla. The focus of the design study was on the inner coil. Demonstration fabrication and testing was performed

  19. Fusion plasma theory. Task III. Auxiliary heating in tokamaks and tandem mirrors. Final report

    International Nuclear Information System (INIS)

    The research we have accomplished with this contract has focused on ICRF coupling, heating and breakeven studies for tokamaks and ECRF fundamental and second harmonic heating in tandem mirrors. The highlights include reviewed publication of ICRF Fokker-Planck heating and breakeven studies with international collaboration with the JET group, fundamental work on a differential equation for wave fields and a new wave power absorption and conservation relation for ICRF in inhomogeneous plasmas and a formulation and code development of slab matrix and differential equation solutions for ICRF waveguide coupling in tokamak edge regions. ECRF ray tracing studies have been carried out, and a reviewed paper published for fundamental and second harmonic propagation, absorption and whistler microinstabilities in tandem mirror plug and barrier regions of Phaedrus, TMX-U and TASKA

  20. Annual progress report on fusion plasma theory task III: auxiliary heating in tokamaks and tandem mirrors

    International Nuclear Information System (INIS)

    The research we have accomplished during the past year has focussed on ICRF coupling, heating and breakeven studies for tokamaks and ECRF fundamental second harmonic heating in tandem mirrors. The studies have included ICRF Fokker-Planck heating and breakeven studies for large tokamaks such as JET, fundamental work on a new wave power absorption and conservation relation for ICRF in inhomogeneous plasmas, a formulation and code development for ICRF waveguide coupling in tokamak edge regions. ECRF ray tracing studies have been carried out for fundamental and second harmonic propagation, absorption and whistler microinstabilities in tandem mirror plug and barrier regions of Phaedrus, TMX-U and TASKA. The two-dimensional velocity space, time dependent Fokker-Planck heating studies have concentrated on D-T breakeven scenarios for fundamental minority deuterium and second harmonic tritium regimes

  1. Synfuels from fusion: using the tandem mirror reactor and a thermochemical cycle to produce hydrogen

    International Nuclear Information System (INIS)

    This study is concerned with the following area: (1) the tandem mirror reactor and its physics; (2) energy balance; (3) the lithium oxide canister blanket system; (4) high-temperature blanket; (5) energy transport system-reactor to process; (6) thermochemical hydrogen processes; (7) interfacing the GA cycle; (8) matching power and temperature demands; (9) preliminary cost estimates; (10) synfuels beyond hydrogen; and (11) thermodynamics of the H2SO4-H2O system

  2. Feasibility study of a fission-suppressed tandem-mirror hybrid reactor

    International Nuclear Information System (INIS)

    Results of a conceptual design study of a U-233 producing fusion breeder consisting of a tandem mirror fusion device and two types of fission-suppressed blankets are presented. The majority of the study was devoted to the conceptual design and evaluation of the two blankets. However, studies in the areas of fusion engineering, reactor safety, fuel reprocessing, other fuel cycle issues, economics, and deployment were also performed

  3. Application of power-factor correction in the Tandem Mirror Experiment Upgrade magnet power supply

    International Nuclear Information System (INIS)

    The magnet power supply for the Tandem Mirror Experiment Upgrade (TMX Upgrade) contains 24 groups of dc rectifiers that feed the water-cooled magnets. Each group consists of five or less rectifiers, connected in series. All 24 are current-regulating, using phase-controlled bilateral thyristors in the rectifier transformer primaries. The electric utility system must furnish reactive power to these phase-controlled thyristors as well as to the cmmutating diodes in the rectifier bridges

  4. Materials considerations for the coupling of thermochemical hydrogen cycles to tandem mirror reactors

    International Nuclear Information System (INIS)

    Candidate materials are discussed and initial choices made for the critical elements in a liquid Li-Na Cauldron Tandem Mirror blanket and the General Atomic Sulfur-Iodine Cycle for thermochemical hydrogen production. V and Ti alloys provide low neutron activation, good radiation damage resistance, and good chemical compatibility for the Cauldron design. Aluminide coated In-800H and siliconized SiC are materials choices for heat exchanger components in the thermochemical cycle interface

  5. Synfuels from fusion: using the tandem mirror reactor and a thermochemical cycle to produce hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Werner, R.W. (ed.)

    1982-11-01

    This study is concerned with the following area: (1) the tandem mirror reactor and its physics; (2) energy balance; (3) the lithium oxide canister blanket system; (4) high-temperature blanket; (5) energy transport system-reactor to process; (6) thermochemical hydrogen processes; (7) interfacing the GA cycle; (8) matching power and temperature demands; (9) preliminary cost estimates; (10) synfuels beyond hydrogen; and (11) thermodynamics of the H/sub 2/SO/sub 4/-H/sub 2/O system. (MOW)

  6. Materials considerations for the coupling of thermochemical hydrogen cycles to tandem mirror reactors

    Energy Technology Data Exchange (ETDEWEB)

    Krikorian, O.H.

    1980-10-10

    Candidate materials are discussed and initial choices made for the critical elements in a liquid Li-Na Cauldron Tandem Mirror blanket and the General Atomic Sulfur-Iodine Cycle for thermochemical hydrogen production. V and Ti alloys provide low neutron activation, good radiation damage resistance, and good chemical compatibility for the Cauldron design. Aluminide coated In-800H and siliconized SiC are materials choices for heat exchanger components in the thermochemical cycle interface.

  7. An alpha loss-cone instability in the central cell of a tandem mirror reactor

    International Nuclear Information System (INIS)

    D-T fusion-born alpha particles are mirror-confined in the central cell of a tandem mirror reactor. The resulting anisotropic loss-cone distribution of the alpha particles in velocity space is capable of destabilizing low frequency plasma waves, thus affecting the energy balance in a tandem mirror plasma. The low frequency waves of a cold, cylindrical, sharp-boundary, D-T plasma are studied. Techniques have been developed to trace the wave propagation regions and search the wave eigenfrequencies. Three branches of waves are found, namely the Alfven, hybrid, and fast waves; but only the Alfven wave is destabilized by the alpha loss-cone instability. The modeling of the alpha distribution function for the linear and quasi-linear instability calculations is done by a diffusion-front method and a numerical finite difference method, respectively. Their validity is established by comparing them with a converged 80-term Legendre function expansion model of the alpha distribution. The growth rate of the instability is basically determined by the alpha number density, the loss-cone angle, and the polarization of the wave. These quantities are in turn mainly affected by the density and temperature of the plasma ions and electrons, the mirror ratio, and the plasma radius. 83 refs., 58 figs

  8. Demonstration of Achromatic Cold-Neutron Microscope Utilizing Axisymmetric Focusing Mirrors

    OpenAIRE

    Liu, D.; Hussey, D; Gubarev, M. V.; Ramsey, B. D.; Jacobson, D.; Arif, M.; Moncton, D.E.; Khaykovich, B.

    2013-01-01

    An achromatic cold-neutron microscope with magnification 4 is demonstrated. The image-forming optics is composed of nested coaxial mirrors of full figures of revolution, so-called Wolter optics. The spatial resolution, field of view, and depth of focus are measured and found consistent with ray-tracing simulations. Methods of increasing the resolution and magnification are discussed, as well as the scientific case for the neutron microscope. In contrast to traditional pinhole-camera neutron i...

  9. Emission spectroscopy measurements on an ECRH non-axisymmetric mirror plasma

    International Nuclear Information System (INIS)

    Time resolved visible emission spectroscopy (300-700 nm) has been performed on ECr heated He, N/sub 2/, and Ar plasmas in the Michigan Mirror Machine (MIMI). The plasma is generated and heated by whistler-mode ECRH at 7.43 GHz and 500W power in 400 μs pulses. Gas is puffed into the mid-plane region where a 2.5 cm quartz window is used to observe the plasma. The plasma is viewed in a direction perpendicular to the mirror axis. Emission spectra are obtained in 100 μs sampling periods starting from the microwave turn-on time using a 0.275 meter spectrograph coupled to a gated, intensified diode array. The majority of light is found to occur from 200-300 μs from microwave turn-on time. Thermal electron temperatures are inferred from the electronic temperature of Ar and He obtained from Atomic Boltzmann plots. Electron temperature varies from 1 eV to 50 eV depending upon gas pressure, microwave power, and mirror and quadrupole field strengths

  10. Hot-electron plasma formation and confinement in the tandem mirror experiment-upgrade

    International Nuclear Information System (INIS)

    The tandem mirror experiment-upgrade (TMX-U) at the Lawrence Livermore National Laboratory (LLNL) is the first experiment to investigate the thermal-barrier tandem-mirror concept. One attractive feature of the tandem magnetic mirror as a commercial power reactor is that the fusion reactions occur in an easily accessible center-cell. On the other hand, complicated end-cells are necessary to provide magnetohydrodynamic (MHD) stability and improved particle confinement of the center-cell plasma. In these end-cells, enhanced confinement is achieved with a particular axial potential profile that is formed with electron-cyclotron range-of-frequency heating (ECRF heating, ECRH). By modifying the loss rates of electrons at spatially distinct locations within the end-cells, the ECRH can tailor the plasma potential profile in the desired fashion. Specifically, the thermal-barrier concept requires generation of a population of energetic electrons near the midplane of each end-cell. To be effective, the transverse (to the magnetic field) spatial structure of the hot-electron plasma must be fairly uniform. In this dissertation we characterize the spatial structure of the ECRH-generated plasma, and determine how the structure builds up in time. Furthermore, the plasma should efficiently absorb the ECRF power, and a large fraction of the electrons must be well confined near the end-cell midplane. Therefore, we also examine in detail the ECRH power balance, determining how the ECRF power is absorbed by the plasma, and the processes through which that power is confined and lost. 43 refs., 69 figs., 6 tabs

  11. Four years of magnet system operation on the Tandem Mirror Experiment-Upgrade (TMX-U)

    Energy Technology Data Exchange (ETDEWEB)

    Pedrotti, L.R.; Jackson, M.C.; Bell, H.H.; Heefner, J.W.; Wong, R.L.

    1985-11-14

    During the past four years, the Tandem Mirror Experiment-Upgrade (TMX-U) magnet system has operated successfully, delivering more than 13,300 full-power shots. This paper presents the expanded physics criteria and how they affect the magnetic field design. It compares our operational results with previously defined criteria for current repeatability, cooling, duty cycle and vacuum integrity. It also details the solutions to a few operational problems, including the discovery and repair of a ground fault in the east plug Ioffe and another in an east plug cee circuit power supply. 14 refs.

  12. Updated reference design of a liquid metal cooled tandem mirror fusion breeder

    International Nuclear Information System (INIS)

    Detailed studies of key techinical issues for liquid metal cooled fusion breeder (fusion-fission hybrid blankets) have been performed during the period 1983-4. Based upon the results of these studies, the 1982 reference liquid metal cooled tandem mirror fusion breeder blanket design was updated and is described. The updated reference blankets provides increased breeding and lower technological risk in comparison with the original reference blanket. In addition to the blanket design revisions, a plant concept, cost, and fuel cycle economics assessment is provided. The fusion breeder continues to promise an economical source of fissile fuel for the indefinite future

  13. Cross-polarization scattering from low-frequency waves in a tandem mirror plasma

    Energy Technology Data Exchange (ETDEWEB)

    Kogi, Yuichiro; Mase, Atsushi; Bruskin, L.G.; Oyama, Naoyuki; Tokuzawa, Tokihiko; Itakura, Akiyosi; Hojo, Hitoshi; Tamano, Teruo [Tsukuba Univ., Ibaraki (Japan). Plasma Research Center

    1997-05-01

    Cross-polarization scattering (CPS) diagnostic was applied to the central-cell plasma of the GAMMA 10 tandem mirror in order to study electromagnetic plasma waves with frequencies of less than 200 kHz. In the CPS process, an incident ordinary (extraordinary) wave is converted to an extraordinary (ordinary) wave by magnetic fluctuations in a plasma. The converted wave propagates through the cutoff layer and reaches the opposite diagnostic port. The experimental data suggest that the power spectral density of the CPS signal satisfies the Bragg condition, while the reflectometer detects the waves near the cutoff layer where the wave number cannot be resolved. (author)

  14. Measurement of ultrashort-pulse cross-polarization scattering in a tandem mirror

    Energy Technology Data Exchange (ETDEWEB)

    Kogi, Yuichiro; Mase, Atsushi [Advanced Science and Technology Center for Cooperative Research, Kyushu University, Kasuga, Fukuoka (Japan); Hojo, Hitoshi; Itakura, Akiyoshi; Ichimura, Makoto; Yatsu, Kiyoshi [Plasma Research Center, Tsukuba Univ., Tsukuba, Ibaraki (Japan)

    2001-08-01

    Cross-polarization scattering (CPS) diagnostics using ultrashort pulse microwaves is applied to the GAMMA 10 tandem mirror for the measurement of internal magnetic fluctuations. The CPS process uses the mode conversion effect of electromagnetic waves by means of magnetic fluctuations in a plasma. The mode contamination of antennas and multiple reflections from the vacuum vessel make the CPS measurement difficult since they easily mask the CPS signal. By using polarizers and performing time-of-flight measurement on the ultrashort pulse, the spurious electromagnetic waves are eliminated and the identification of the CPS process is successful. (author)

  15. Four years of magnet system operation on the Tandem Mirror Experiment Upgrade

    International Nuclear Information System (INIS)

    During the past four years, the Tandem Mirror Experiment-Upgrade (TMX-U) magnet system has operated successfully, delivering more than 13,300 full-power shots. This paper presents the expanded physics criteria and how they affect the magnetic field design. It compares our operational results with previously defined criteria for current repeatability, cooling, duty cycle and vacuum integrity. It also details the solutions to a few operational problems, including the discovery and repair of a ground fault in the east plug Ioffe and another in an east plug cee circuit power supply

  16. Four years of magnet system operation on the Tandem Mirror Experiment-Upgrade (TMX-U)

    International Nuclear Information System (INIS)

    During the past four years, the Tandem Mirror Experiment-Upgrade (TMX-U) magnet system has operated successfully, delivering more than 13,300 full-power shots. This paper presents the expanded physics criteria and how they affect the magnetic field design. It compares our operational results with previously defined criteria for current repeatability, cooling, duty cycle and vacuum integrity. It also details the solutions to a few operational problems, including the discovery and repair of a ground fault in the east plug Ioffe and another in an east plug cee circuit power supply. 14 refs

  17. Studies of plasma transport relevant to tandem mirrors. Final technical report, March 1, 1982-February 28, 1985

    International Nuclear Information System (INIS)

    Experiments were performed on a pure electron plasma device. These plasmas are exceptionally well confined and their low background loss rate makes them well suited for controlled transport experiments. The confinement of electrons in these devices is similar to the confinement of ions in the central cell of a tandem mirror, i.e., the radial confinement is provided by a solenoidal magnetic field while the axial confinement is provided by electrostatic potentials. In addition, the various scaled parameters which are thought to determine the nature of the radial transport are similar for the two devices. However, the construction, operation, and understanding of the pure electron plasma is relatively simple compared to a tandem mirror machine. These considerations suggest that the pure electron plasma can be effectively employed to study the basic elements of the plasma transport theory used to describe radial particle losses in tandem mirrors

  18. Neutronics shielding analysis for the end plug of a tandem mirror fusion reactor

    Science.gov (United States)

    Ragheb, Magdi M. H.; Maynard, Charles W.

    1981-10-01

    A neutronics analysis using the Monte Carlo method is carried out for the end-plug penetration and magnet system of a tandem mirror fusion reactor. Detailed penetration and the magnets' three-dimensional configurations are modeled. A method of position dependent angular source biasing is developed to adequately sample the DT fusion source in the central cell region and obtain flux contributions at the penetration components. To assure cryogenic stability, the barrier cylindrical solenoid is identified as needing substantial shielding of about 1 m of a steel-lead-boron-carbide-water mixture. Heating rates there would require a thermal-hydraulic design similar to that in the central cell blanket region. The transition coils, however, need a minimal 0.2 m thickness shield. The leakage neutron flux at the direct converters is estimated at 1.3×1015 n/(m2·s), two orders of magnitude lower than that reported at the neutral beam injectors for tokamaks around 1017 n/(m2·s) for a 1 MW/m2 14 MeV neutron wall loading. This result is obtained through a coupling between the nuclear and plasma physics designs in which hydrogen ions rather than deuterium atoms are used for energy injection at the end plug, to avoid creating a neutron source there. This lower and controllable radiation leakage problem is perceived as a potential major advantage of tandem mirrors compared to tokamaks and laser reactor systems.

  19. Divertor simulation experiment and its future research plan making use of a large tandem mirror device

    International Nuclear Information System (INIS)

    Divertor simulation study has been started as a new research plan, by making best use of a large linear plasma device. The experiment of generating the plasma flow with high heat and particle flux was successfully performed at an end-mirror exit of the GAMMA 10 tandem mirror. In typical hot-ion-mode plasmas, the heat-flux density of 0.6 MW/m2 and the particle-flux density of 1022 particles/s m2 were simultaneously achieved in the case of only ICRF heating and superimposing the 300 kW ECH pulse attained the peak value of the net heat-flux up to 8 MW/m2 on axis. The above experimental results and the simulation analysis of ICRF heating using the Fokker-Planck code give a clear prospect of generating the required performance for divertor studies by building up the plasma heating systems to the end-mirror cell. Detailed behavior of the plasma flow and the future research plan are also described.

  20. Chemical engineering challenges in driving thermochemical hydrogen processes with the tandem mirror reactor

    International Nuclear Information System (INIS)

    The Tandem Mirror Reactor is described and compared with Tokamaks, both from a basic physics viewpoint and from the suitability of the respective reactor for synfuel production. Differences and similarities between the TMR as an electricity producer or a synfuel producer are also cited. The Thermochemical cycle chosen to link with the fusion energy source is the General Atomic Sulfur-Iodine Cycle, which is a purely thermal-driven process with no electrochemical steps. There are real chemical engineering challenges of getting this high quality heat into the large thermochemical plant in an efficient manner. We illustrate with some of our approaches to providing process heat via liquid sodium to drive a 1050 K, highly-endothermic, catalytic and fluidized-bed SO3 Decomposition Reactor. The technical, economic, and safety tradeoffs that arise are discussed

  1. ION cyclotron radio frequency systems and performance on the Tandem Mirror Experiment-Upgrade

    International Nuclear Information System (INIS)

    High power ion cyclotron radio frequency (ICRF) systems are now gaining greater attention than before as prime driver ion heating systems. Lawrence Livermore National Laboratory (LLNL) has installed a 200 kW high frequency (HF) transmitter system on its Tandem Mirror Experiment-Upgrade (TMX-U). This paper describes the system, antenna, controls, and monitoring apparatus. The transmitter operates into a high Q antenna installed in the central cell region of the experiment. It incorporates a dual-port feedback system to automatically adjust the transmitter's output power and allow the maximum consistent with the plasma loading of the antenna. Special techniques have been used to measure, in real-time, the dynamically changing loading values presented by the plasma. From the measurements, the antenna impedance can be optimized for specified plasma density

  2. Applications of small computers for systems control on the Tandem Mirror Experiment-Upgrade

    International Nuclear Information System (INIS)

    Desktop computers operating into a CAMAC-based interface are used to control and monitor the operation of the various subsystems on the Tandem Mirror Experiment-Upgrade (TMX-U) at Lawrence Livermore National Laboratory (LLNL). These systems include: shot sequencer/master timing, neutral beam control (four consoles), magnet power system control, ion-cyclotron resonant heating (ICRH) control, thermocouple monitoring, getter system control, gas fueling system control, and electron-cyclotron resonant heating (ECRH) monitoring. Two additional computers are used to control the TMX-U neutral beam test stand and provide computer-aided repair/test and development of CAMAC modules. These machines are usually programmed in BASIC, but some codes have been interpreted into assembly language to increase speed. Details of the computer interfaces and system complexity are described as well as the evolution of the systems to their present states

  3. TASKA-M - a low cost, near term tandem mirror device for fusion technology testing

    International Nuclear Information System (INIS)

    TASKA-M (Modifizierte Tandem Spiegelmaschine Karlsruhe) is a study of a dedicated fusion technology device based on the mirror principle, in continuation of the 1981/82 TASKA study. The main objective is to minimize cost while retaining key requirements of neutron flux and fluence for blanket and material development and for component testing in a nuclear environment. Direct costs are reduced to about 400 M$ by dropping reactor-relevant aspects not essential to technology testing: No thermal barrier and electrostatic plugging of the plasma; fusion power of 7 MW at an injected power of 44 MW; tritium supply from external sources. All technologies for operating the machine are expected to be available by 1990; the plasma physics relies on microstabilization in a sloshing ion population. (orig.)

  4. Plasma engineering for MINIMARS: a small commercial tandem mirror reactor with octopole plugs

    International Nuclear Information System (INIS)

    With the employment of a novel octopole end plug scheme, we examine the plasma engineering design of MINIMARS, a small compact fusion reactor based on the tandem mirror principle. With a net electric output of 600 MW/sub e/, MINIMARS is expressly designed for short construction times, factory built modules, and a passively safe blanket system. We show that the compact octopole/mantle provides several distinct improvements over the more conventional quadrupole (yin-yang) end plugs and enables ignition to be obtained with much shorter central cell length. In this way we can design economic small reactors which will minimize utility financial risk and provide attractive alternatives to the conventional larger fusion plants encountered to date

  5. Synfuels from fusion: producing hydrogen with the tandem mirror reactor and thermochemical cycles

    International Nuclear Information System (INIS)

    This report examines, for technical merit, the combination of a fusion reactor driver and a thermochemical plant as a means for producing synthetic fuel in the basic form of hydrogen. We studied: (1) one reactor type - the Tandem Mirror Reactor - wishing to use to advantage its simple central cell geometry and its direct electrical output; (2) two reactor blanket module types - a liquid metal cauldron design and a flowing Li2O solid microsphere pellet design so as to compare the technology, the thermal-hydraulics, neutronics and tritium control in a high-temperature operating mode (approx. 1200 K); (3) three thermochemical cycles - processes in which water is used as a feedstock along with a high-temperature heat source to produce H2 and O2

  6. Magnet power control system for the Tandem Mirror Experiment-Upgrade

    International Nuclear Information System (INIS)

    This paper describes the desktop computer/CAMAC-based system that controls the power source for the Tandem Mirror Experiment-Upgrade (TMX-U) magnet power system. Presently it contains 42 dc rectifier power supplies connected to 24 magnet coils arranged in 17 circuits. During each shot, the system delivers 22.6 MW dc to the magnets for about 3 s. The system is presently being changed to add six power supplies, two solenoidal throttle coils, and two reverse C-coils. When complete, the delivered power will increase to 36.9 MW. The closed-loop control system usually provides current (and thus, magnetic field) that is within 1% of the requested current. Achieving this accuracy required using grounding, shielding, and isolation methods to reduce noise and related problems. These are also discussed

  7. The time-of-flight neutral particle analyzer on the Tandem Mirror Experiment-Upgrade

    International Nuclear Information System (INIS)

    The authors have recently installed a time-of-flight (TOF) neutral particle analyzer on the east end cell of the Tandem Mirror Experiment-Upgrade (TMX-U). The TOF analyzer consists of a modified turbo-molecular pump for use as a particle chopper, a 7-meter flight path and a secondary emission type particle detector. The TOF analyzer is designed to measure the velocity distribution of escaping charge exchange neutral particles (D0) with energies between 20 and 5000eV. The analyzer is presently viewing the midplane of the east plug at an angle of 22.6 degrees with respect to the magnetic field. This location and orientation is within the magnetic loss cone of the end cell. This allows study of the velocity distribution of the potentially confined ions. Initial data have shown an increase in signal magnitude during operation with end plugging

  8. Utilizing subcooled, superfluid He-II in the design of a 12-Tesla tandem mirror experiment

    International Nuclear Information System (INIS)

    A design study of 12-T yin-yang coils for a conceptual Tandem Mirror Next Step facility has been recently performed by Lawrence Livermore National Laboratory in conjunction with the Convair Division of General Dynamics. The large magnets have major and mirror radii of 3.7 and 1.5 m, 0.70 x 3.75 m2 cross section, 46.3 MA turns, and an overall current density of 1765 A/cm2, obtained by the use of Nb3Sn and Nb-Ti superconductors. Each coil is composed of several subcoils separated by internal strengthening substructure to react the enormous electromagnetic forces. The size of the yin-yang coils, and hence the current density, was reduced by utilizing subcooled, superfluid He-II at 1.8 K for the coolant. This paper reviews the design study, with emphasis on He-II heat transport and conductor stability. Methods are also presented which allow the extension of Gorter-Mellink-channel calculations to encompass multiple, interconnecting coolant channels

  9. Design, construction, and testing of the vacuum vessel for the tandem Mirror Fusion Test Facility

    International Nuclear Information System (INIS)

    In 1980, the US Department of Energy gave the Lawrence Livermore National Laboratory approval to design and build a tandem Mirror Fusion Test Facility (MFTF-B) to support the goals of the National Mirror Program. We designed the MFTF-B vacuum vessel both to maintain the required ultrahigh vacuum environment and to structurally support the 42 superconducting magnets plus auxiliary internal and external equipment. During our design work, we made extensive use of both simple and complex computer models to arrive at a cost-effective final configuration. As part of this work, we conducted a unique dynamic analysis to study the interaction of the 32,000-tonne concrete-shielding vault with the 2850-tonne vacuum vessel system. To maintain a vacuum of 2 x 10-8 Torr during the physics experiments inside the vessel, we designed a vacuum pumping system of enormous capacity. The vacuum vessel (4200 m3) has been fabricated, erected, and acceptance tests have been completed at the Livermore site. The rest of the machine has been assembled, and individual systems have been successfully checked. On October 1, 1985, we began a series of integrated engineering tests to verify the operation of all components as a complete system

  10. Design, construction, and testing of the vacuum vessel for the tandem Mirror Fusion Test Facility

    International Nuclear Information System (INIS)

    In 1980, the U.S. Department of Energy gave the Lawrence Livermore National Laboratory approval to design and build a tandem Mirror Fusion Test Facility (MFTF-B) to support the goals of the National Mirror Program. We designed the MFTF-B vacuum vessel both to maintain the required ultrahigh vacuum environment and to structurally support the 42 superconducting magnets plus auxiliary internal and external equipment. During our design work, we made extensive use of both simple and complex computer models to arrive at a cost-effective final configuration. As part of this work, we conducted a unique dynamic analysis to study the interaction of the 32 000 tonne concrete-shielding vault with the 2850 tonne vacuum vessel system. To maintain a vacuum of 2 x 10-8 Torr during the physics experiments inside the vessel, we designed a vacuum pumping system of enormous capacity. The vacuum vessel (4200 m3) has been fabricated, erected, and acceptance tests have been completed at the Livermore site. The rest of the machine has been assembled, and individual systems have been successfully checked. On October 1, 1985, we began a series of integrated engineering tests to verify the operation of all components as a complete system

  11. Problems of gas control and fueling in the Tara tandem mirror

    International Nuclear Information System (INIS)

    Control of the edge neutral pressure is critical for successful thermal barrier operation of tandem mirrors. High neutral pressures lead to substantial charge exchange losses of plasma ions as well as creating a population of cold ions and electrons which may be electrostatically trapped in the negative and positive confining potentials in the end cells. The primary sources of neutral gas in Tara are central cell and transition gas injection, and neutral beam injection in the plugs. In the central cell, the region of ionization is separated from the mirror-trapped hot ion region. Gettering in the region of hot ions, controls reflux and reduces the central cell gas contribution to the plug. During end plugging, the plasma stream from the central cell which is used to fuel the minimum B anchor cells is cut off, so that gas fueling must be supplied in the transition region. The beamlines and dumps use LN/Ti pumps, baffling and bakeable dumps and scrapers to limit gas penetration to the plug plasma. Gettering of the plug wall and geometric considerations are used to control reflux from charge exchange. Monte-Carlo simulations are used to analyze the plug and central cell reflux. A new central cell configuration employing a midplane magnetic divertor is now being evaluated. The halo plasma produced in the diverted magnetic flux will be used to improve shielding of the core plasma from charge exchange

  12. START/TM: a study of start-up and fractional power operation of tandem mirror fusion reactors

    International Nuclear Information System (INIS)

    Start-up, shutdown and fractional power operation are important parts of power reactor operation. Special requirements for operation during these phases often place design constraints on key subsystems and can influence the fundamental design approach. This report presents investigations of these problems for tandem mirror fusion reactors (TMR's) and is referred to as the START/TM study. As a basis for the work, the MARS conceptual tandem mirror reactor design is used as the general reactor model. An overall framework is developed for start-up and fractional power increases to full power, applicable to any fusion reactor. Five phases are identified that include initial commissioning, cold or hot shutdown, system testing and plasma initiation to a standby mode, staged power increases, and rated power operation. Both general and specific constraints associated with these phases are identified and a plasma shutdown scenario is developed

  13. Conceptual design study FY 1981: synfuels from fusion - using the tandem mirror reactor and a thermochemical cycle to produce hydrogen

    International Nuclear Information System (INIS)

    This report represents the second year's effort of a scoping and conceptual design study being conducted for the express purpose of evaluating the engineering potential of producing hydrogen by thermochemical cycles using a tandem mirror fusion driver. The hydrogen thus produced may then be used as a feedstock to produce fuels such as methane, methanol, or gasoline. The main objective of this second year's study has been to obtain some approximate cost figures for hydrogen production through a conceptual design study

  14. Computer aided design on the Tandem Mirror Experiment Upgrade (TMX-U)

    International Nuclear Information System (INIS)

    The Tandem Mirror Experiment-Upgrade (TMX-U) at Lawrence Livermore National Laboratory (LLNL) has been using a Computer Aided Design (CAD) graphics system to enhance its design capabilities since November of 1984. Three-dimensional models of the TMX-U magnet set, neutral beams, plasma, and containment vessel have been modeled on the system. These models are used for location verification, diagnostic placement, interference checking, and visualization of complex shapes generated on the Magnetic Fusion Energy Computer Center (MFECC) mainframes. The graphics system used at LLNL is a Computervision multi-application graphics system. Four other fusion laboratories, Princeton, Oak Ridge, General Atomic, and Los Alamos, have purchased this same CAD system. These sites are linked through the MFE computer network to allow for the exchange of design files and the transfer of physics and engineering data to and from the CAD systems. This paper gives examples of how the CAD system has been used to solve design and engineering problems for the TMX-U

  15. Trapped particle instability and flute instability in tandem mirror; scale separation closure in Alfven wave turbulence

    International Nuclear Information System (INIS)

    We have constructed a quadratic dispersion relation, in which various MHD and kinetic effects like ion diamagnetism, electron diamagnetism, electron-electron electron-ion collisions, ion Landau-damping, E x B drift and energetic particles are included and treated in a systematic way. The numerical study in which we use the formalism to investigate the two most likely instabilities in tandem mirror machines produced many quantitative and qualitative results about the two modes. We have proposed a physically motivated, non-perturbative closure scheme to deal with some problems in plasma or fluid turbulence. After discussing a few simple analytically tractable applications, we have applied our formalism to a model problem: the shear-Alfven turbulence. The problem is readily solved numerically to obtain the turbulent spectrum with the following features: the calculated spectrum has explicit frequency shift from the linear theory as well as explicit band-broadening in k, ω space; the frequency integrated spectrum obeys a power law in the intermediate k range, i.e., I/sub k/ /approximately/ K/sup -α/, where α approaches the value 2 in the case we studied; and the form of the power law is hardly influenced by changing low-k, high-k damping effects, or by changing the strength of the turbulence. It is very encouraging that this closure scheme is capable of producing essential features associated with a turbulence spectrum. 66 refs., 38 figs

  16. Influence of anisotropic ion heating on confinement of the tandem mirror

    International Nuclear Information System (INIS)

    Ion transport in the velocity space due to the Alfven ion-cyclotron (AIC) fluctuation was investigated using a developed diagnostic device ELECA (end-loss energy component analyzer) in the tandem mirror. The AIC waves are excited spontaneously in the central cell by carrying out anisotropic ion heating with injection of the ion-cyclotron range of frequency (ICRF) wave. Hump structure was observed on the energy distribution function of the end-loss ions, and was correlated with the excitation of the AIC wave. A remarkable feature is that trapped ions with characteristic energy flow selectively into the loss region so as to cause the hump structure which appears in the energy region (1.0-5.0) keV. The AIC waves enhance the ion diffusion from the trapped region to the loss region in the velocity space, and decrease the confinement. However, it was found that the hump structure decreased in the high potential mode and the high confining potential more than 3 kV could confine a large mount of loss energy flux due to the AIC fluctuations because of the existence of the upper limit of the hump energy, even in strong excitation of the AIC wave caused by high anisotropy. (author)

  17. A tandem mirror plasma source for a hybrid plume plasma propulsion concept

    Science.gov (United States)

    Yang, T. F.; Miller, R. H.; Wenzel, K. W.; Krueger, W. A.; Chang, F. R.

    1985-01-01

    This paper describes a tandem mirror magnetic plasma confinement device to be considered as a hot plasma source for the hybrid plume rocket concept. The hot plasma from this device is injected into an exhaust duct, which will interact with an annular layer of hypersonic neutral gas. Such a device can be used to study the dynamics of the hybrid plume and to experimentally verify the numerical predictions obtained with computer codes. The basic system design is also geared toward being lightweight and compact, as well as having high power density (i.e., several kW/sq cm) at the exhaust. This feature is aimed toward the feasibility of 'space testing'. The plasma is heated by microwaves. A 50 percent heating efficiency can be obtained by using two half-circle antennas. The preliminary Monte Carlo modeling of test particles result reported here indicates that interaction does take place in the exhaust duct. Neutrals gain energy from the ion, which confirms the hybrid plume concept.

  18. Generation of sloshing ions in a tandem mirror by ion cyclotron resonance heating

    International Nuclear Information System (INIS)

    Experimental results indicate that ion cyclotron resonance heating at omega = omega/sub C1/ can create a population of sloshing ions in a minimum /B/ end cell of a tandem mirror. This effect can be mathematically modeled by a kick-per-pass operator which strongly heats the cold and warm ions. An anisotropy is seen in the pitch-angle distribution of the warm (over 200 eV) ions as obtained from measurements by arrays of secondary emission detectors. The various issues involved in the creation of such a sloshing population are examined, including charge exchange losses, radial profile effects, Coulomb scattering and RF diffusion. The author presents the functional dependence of this anisotropy with RF resonance position, radius, RF power level, and background neutral gas density. He finds that the interaction of the ICRF waves with the warm to hot RF sustained plasma distribution can be approximately modeled with RF quasi-linear theory or with Monte Carlo kick-per-pass operators. The ion pitch angle distribution is modeled by assuming an initial distribution narrowly centered at the RF pitch angle. This distribution is then predominantly diffused by ICRF to a wider distribution. The midplane pitch-angle standard deviation is measured to be 15 to 250 from a mean at 700, a distribution obtained by placing the ICRF resonance 19-20 centimeters off midplane

  19. Parametric study of axisymmetric fusion devices

    International Nuclear Information System (INIS)

    Three different axisymmetric magnetic mirror fusion machines are examined in order to optimize the ratio the fusion power produced by them to the power injected into them to maintain the plasma. These three devices were chosen to study the continuum between a simple mirror and a tandem mirror. This allowed the evolutionary process leading from the simple to the tandem mirror to be examined in detail. The Kelley mirror, which corresponds to the middle step, was examined in depth for the first time. A computer code that models the plasma in these machines was written to investigate the steady-state operation of these machines. The balance equations are solved by using an ordinary differential equation solver, LSODE, to numerically solve the system of differential equations. The computer model was used to examine parameter space to optimize Q for each of the three machines. When feasible, a comparison with a Fokker-Planck code was made for the optimal Q case for each machine. Finally, the possible roles these devices might fill was discussed

  20. Measurements of radial profiles of ion cyclotron resonance heating on the Tandem Mirror Experiment-Upgrade

    International Nuclear Information System (INIS)

    A small Radial Energy Analyzer (REA) was used on the Tandem Mirror Experiment-Upgrade (TMX-U), at Lawerence Livermore National Laboratory, to investigate the radial profiles of ion temperature, density, and plasma potential during Ion Cyclotron Resonance Heating (ICRH). The probe has been inserted into the central-cell plasma at temperatures of 200 eV and densities of 3 x 1012cm/sup /minus 3// without damage to the probe, or major degradation of the plasma. This analyzer has indicated an increase in ion temperature from near 20 eV before ICRH to near 150 eV during ICRH, with about 60 kW of broadcast power. The REA measurements were cross-checked against other diagnostics on TMX-U and found to be consistent. The ion density measurement was compared to the line-density measured by microwave interferometry and found to agree within 10 to 20%. A radial intergral of n/sub i/T/sub i/ as measured by the REA shows good agreement with the diamagnetic loop measurement of plasma energy. The radial density profile is observed to broaden during the RF heating pulses, without inducing additional radial losses in the core plasma. The radial profile of plasma is seen to vary from axially peaked, to nearly flat as the plasma conditions carried over the series of experiments. To relate the increase in ion temperature to power absorbed by the plasma, a power balance as a function of radius was performed. The RF power absorbed is set equal to the sum of the losses during ICRH, minus those without ICRH. This method accounts for more than 70% of the broadcast power using a simple power balance model. The measured radial profile of the RF heating was compared to the calculations of two codes, ANTENA and GARFIELD, to test their effectiveness as predictors of power absorption profiles for TMX-U. 62 refs., 63 figs., 7 tabs

  1. Development of procedures to ensure quality and integrity in Tandem Mirror Experiment-Upgrade (TMX-U) diagnostics systems

    International Nuclear Information System (INIS)

    The diagnostic systems for Tandem Mirror Experiment-Upgrade (TMX-U) have grown from eleven initial systems to more than twenty systems. During operation, diagnostic system modifications are sometimes required to complete experimental objectives. Also, during operations new diagnostic systems are being developed and implemented. To ensure and maintain the quality and integrity of the data signals, a set of plans and systematic actions are being developed. This paper reviews the procedures set in place to maintain the integrity of existing data systems and ensure the performance objectives of new diagnostics being added

  2. Polarizing holographic reflector for electron cyclotron resonant heating (ECRH) on the Tandem Mirror Experiment Upgrade (TMX-U)

    International Nuclear Information System (INIS)

    A reflector for electron cyclotron resonant heating on the Tandem Mirror Experiment Upgrade has been designed to convert the high-power TE01 output of the circular waveguide system into a linearly polarized gaussian intensity pattern in the plasma. The reflector is a computer-generated holographic optical element with a twist polarizer. Its design, fabrication, and performance are discussed. Results of the low- and high-power tests are presented. Low-power tests were used to determine the beam pattern and the degree of cross-polarization. High-power tests verified that arcing across the grooves of the twist polarizer does not occur

  3. Technician support for operation and maintenance of large fusion experiments: the tandem mirror experiment upgrade (TMX-U) approach

    International Nuclear Information System (INIS)

    As experiments continue to grow in size and complexity, a few technicians will no longer be able to maintain and operate the complete experiment. Specialization is becoming the norm. Subsystems are becoming very large and complex, requiring a great deal of experience and training for technicians to become qualified maintenance/operation personnel. Formal in-house and off-site programs supplement on-the-job training to fulfill the qualification criteria. This paper presents the Tandem Mirror Experiment-Upgrade (TMX-U) approach to manpower staffing, some problems encountered, possible improvements, and safety considerations for the successful operation of a large experimental facility

  4. Conceptual design study FY 1981: synfuels from fusion - using the tandem mirror reactor and a thermochemical cycle to produce hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Krikorian, O.H. (ed.)

    1982-02-09

    This report represents the second year's effort of a scoping and conceptual design study being conducted for the express purpose of evaluating the engineering potential of producing hydrogen by thermochemical cycles using a tandem mirror fusion driver. The hydrogen thus produced may then be used as a feedstock to produce fuels such as methane, methanol, or gasoline. The main objective of this second year's study has been to obtain some approximate cost figures for hydrogen production through a conceptual design study.

  5. TMRBAR: a code to calculate plasma parameters for tandem-mirror reactors operating in the MARS mode

    International Nuclear Information System (INIS)

    The purpose of this report is to document the plasma power balance model currently used by LLNL to calculate steady state operating points for tandem mirror reactors. The code developed from this model, TMRBAR, has been used to predict the performance and define supplementary heating requirements for drivers used in the Mirror Advanced Reactor Study (MARS) and for the Fusion Power Demonstration (FPD) study. The equations solved included particle and energy balance for central cell and end cell species, quasineutrality at several cardinal points in the end cell region, as well as calculations of volumes, densities and average energies based on given constraints of beta profiles and fusion power output. Alpha particle ash is treated self-consistently, but no other impurity species is treated

  6. Magnetic mirror confinement concepts system studies

    International Nuclear Information System (INIS)

    This report discusses the following topics: world survey of mirror confinement research facilities; data base on mirror confinement program budget milestone; Fokker-Planck modeling of tandem mirror confinement; review of diagnostic capabilities for tandem mirror research; tandem mirror reactor concept development; tandem mirror data base; and primer on tokamak confinement

  7. TANDEM

    Data.gov (United States)

    Federal Laboratory Consortium — The Tandem Van de Graaff facility provides researchers with beams of more than 40 different types of ions - atoms that have been stripped of their electrons. One of...

  8. Mirror fusion reactors

    International Nuclear Information System (INIS)

    Conceptual design studies were made of fusion reactors based on the three current mirror-confinement concepts: the standard mirror, the tandem mirror, and the field-reversed mirror. Recent studies of the standard mirror have emphasized its potential as a fusion-fission hybrid reactor, designed to produce fuel for fission reactors. We have designed a large commercial hybrid and a small pilot-plant hybrid based on standard mirror confinement. Tandem mirror designs include a commercial 1000-MWe fusion power plant and a nearer term tandem mirror hybrid. Field-reversed mirror designs include a multicell commercial reactor producing 75 MWe and a single-cell pilot plant

  9. Ion cyclotron radio frequency systems and performance on the tandem mirror experiment-upgrade (TMX-U)

    International Nuclear Information System (INIS)

    High power ion cyclotron radio frequency (ICRF) systems are now gaining greater attention than before as prime driver ion heating systems. Lawrence Livermore National Laboratory (LLNL) has installed a 200 kW high frequency (HF) transmitter system on its Tandem Mirror Experiment-Upgrade (TMX-U). This paper describes the system, antenna, controls, and monitoring apparatus. The transmitter operates into a high Q antenna installed in the central cell region of the experiment. It incorporates a dual-port feedback system to automatically adjust the transmitter's output power and allow the maximum consistent with the plasma loading of the antenna. Special techniques have been used to measure, in real-time, the dynamically changing loading values presented by the plasma. From the measurements, the antenna impedance can be optimized for specified plasma density

  10. Description of the Plasma Potential Control (PPC) System on the Tandem Mirror Experiment-Upgrade (TMX-U)

    International Nuclear Information System (INIS)

    A set of 18 separately controlled plates have been added to each end of the Tandem Mirror Experiment Upgrade (TMX-U) vessel to allow measurement of end-wall currents and to provide a means of plasma potential control (PPC). These plates are shaped to form elliptical rings separated into quadrants. Each plate can be individually grounded, float at plasma potentials, or be actively biased to control the plasma. Voltage and current monitoring are provided for each of the plates, and the control and monitoring functions are controlled by the PPC system computer. The details of the field line mapping and the plate shapes are discussed, and the control architecture and performance are presented. 1 ref., 5 figs

  11. Mirroring

    DEFF Research Database (Denmark)

    Wegener, Charlotte; Wegener, Gregers

    2016-01-01

    Most definitions of creativity emphasise originality. The creative product is recognised as distinct from other products and the creative person as someone who stands out from the crowd. What tend to be overlooked are acts of mirroring as a crucial element of the creative process. The human abili...

  12. Extended consolidation of scaling laws of potentials covering over the representative tandem-mirror operations in GAMMA 10

    International Nuclear Information System (INIS)

    Scaling laws of potential formation and associated effects are constructed in the GAMMA 10 tandem mirror. A novel proposal of extended consolidation and generalization of the two major theories of (i) Cohen's strong electron cyclotron heating (ECH) theory for the formation physics of plasma confining potentials, and (ii) the generalized Pastukhov theory for the effectiveness of the produced potentials on plasma confinement is made through the use of the energy-balance equation. This proposal is then followed by the verification from experimental data in two representative operational modes, characterized in terms of (i) a high-potential mode having kV-order plasma-confining potentials, and (ii) a hot-ion mode yielding fusion neutrons with 10-20 keV bulk-ion temperatures. The importance of the validity of the proposed consolidated physics-based scaling is highlighted by a possibility of extended capability inherent in Pastukhov's prediction of requiring ion-confining potential (φc) of 30 kV for a fusion Q value of unity on the basis of an application of Cohen's potential formation method. In addition to the above potential physics scaling, an externally controllable parameter scaling including both plug and barrier ECH powers for potential formation is investigated. The combination of (i) the physics scaling of the above-proposed consolidation over potential formation and effects with (ii) the externally controllable practical ECH power scaling provides a scalable way for the future tandem-mirror researches. Under the assumption of the validity of the extension of the present theoretically well interpreted scaling, the formation of Pastukhov's predicted φc for confining Q=1 plasmas is scaled to require total plug with barrier ECH powers of 3 MW. (author)

  13. Monte Carlo studies of tandem-mirror plasmas interacting with waves in the ion-cyclotron range of frequencies (ICRF). Annual report, October 1, 1982-September 30, 1983

    International Nuclear Information System (INIS)

    A study of RF start-up, RF Fueling, and RF Anchor operation in Tandem Mirrors has been completed. Significant results include finding little performance difference between inboard and outboard antennas, and an optimum central-cell electron-to-ion-temperature ratio of between one and two. Several variance-reduction techniques, improved RF operators and a Monte Carlo neutral model have been incorporated in the code. Ongoing activities include studies of central-cell ICRF heating and hot-electron anchor operation of Tandem Mirrors, and Development of Monte Carlo non-maxwellian scattering operators. Completion of these ongoing activities, conversion of our Monte Carlo ICRF code to the NMECC CRAYS, and initial development of a new Monte Carlo RF code for 3-D mirror equilibrium geometries comprises our proposed program for FY '84

  14. Plasma characteristics of the end-cell of the GAMMA 10 tandem mirror for the divertor simulation experiment

    International Nuclear Information System (INIS)

    In this paper, detailed characteristics and controllability of plasmas emitted from the end-cell of the GAMMA 10 tandem mirror are described from the viewpoint of divertor simulation studies. The energy analysis of ion flux by using end-loss ion energy analyzer (ELIEA) proved that the obtained high ion temperature (100 - 400 eV) was comparable to SOL plasma parameters in toroidal devices and was controlled by changing the ICRF power. Parallel ion temperature Ti∥ determined from the probe and calorimeter shows a linear relationship with the ICRF power in the central-cell and agrees with the results of ELIEA. Additional ICRF heating revealed a significant enhancement of particle flux, which indicated an effectiveness of additional plasma heating in adjacent cells toward the improvement of the performance. Superimposing the ECH pulse of 380 kW, 5 ms attained the maximum heat-flux more than 10 MW/m2 on axis. This value comes up to the heat-load of the divertor plate of ITER, which gives a clear prospect of generating the required heat density for divertor studies by building up heating systems to the end-mirror cell. Initial results of plasma irradiation experiment and construction of new divertor module are also described. (author)

  15. Tandem mirror experiment upgrade (TMX-U) throttle, mechanical design, construction, installation, and alignment

    International Nuclear Information System (INIS)

    We will soon add a high-field axisymmetric throttle region to the central cell of the TMX-U. Field amplitude will be adjusted between 2.25 and 6.0 T. This field is produced by adding a high-field solenoid and a cee coil to each end of the central cell. We describe these coils as well as the additions to the restraint structure. We analyzed the stresses within the solenoid using the STANSOL code. In addition, we performed a finite-element structural analysis of the complete magnet set with the SAP4 code. Particular attention was paid to the transition section where the new magnets were added and where the currents in the existing magnets were increased. The peak temperature rise in the throttle coil was calculated to be 410C above ambient

  16. Special topics reports for the reference tandem mirror fusion breeder. Volume 4. Structural analysis

    Energy Technology Data Exchange (ETDEWEB)

    Orient, G.; Westmann, R.A.; Ghoniem, N.M.; Garner, J.K.; Gromada, R.G.

    1984-12-01

    This report presents a structural analysis of the reference fission suppressed fusion breeder blanket. An axisymmetric structural model is used to analyze thermal and pressure stresses in the blanket. Results indicate that the first wall must be decoupled from the back of the blanket to avoid large thermal stresses. The composite first wall appears to be adequate to resist buckling, and is further strengthened by radial diaphragms. Semieliptical closures for the module ends appear to be feasible, although the attachment of these end closures to the composite first wall has not been analyzed. Radiation effects have not been included in the structural model, but an assessment of creep and swelling indicates a 4 to 5 year blanket life at an assumed strain limit of 2%. Design modifications which will reduce thermal stresses and simplify manufacturing are recommended.

  17. Fusion plasma theory. Task II. ECRH and transport modeling in tandem mirrors and divertor physics. Annual progress report, January 1, 1984-September 30, 1984

    International Nuclear Information System (INIS)

    The research performed under Tank II of this contract has focused on (1) the coupling of an ECRH ray tracing and absorption code to a tandem mirror transport code in order to self-consistently model the temporal and spatial evolution of the plasma, and (2) the further development of semi-analytical models for plasma flow in divertors and pumped limiters. Work on these topics is briefly summarized in this progress report

  18. Task II: ECRH and transport modeling in tandem mirrors and divertor physics. Annual progress report on fusion plasma theory, January 1, 1983-December 31, 1983

    International Nuclear Information System (INIS)

    The research performed under Task II of this contract has focused on (1) the coupling of an ECRH ray tracing and absorption code to a tandem mirror transport code in order to self-consistently model the temporal and spatial evolution of the plasma, and (2) the further development of a semi-analytical kinetic model for plasma flow in divertors and pumped limiters. Work on these topics is briefly summarized in this progress report

  19. Design and fabrication of circular and rectangular components for electron-cyclotron-resonant heating of tandem mirror experiment-upgrade

    International Nuclear Information System (INIS)

    The electron-cyclotron-resonant heating (ECRH) systems of rectangular waveguides on Tandem Mirror Experiment-Upgrade (TMX-U) operated with a overall efficiency of 50%, each system using a 28-GHz, 200-kW pulsed gyrotron. We designed and built four circular-waveguide systems with greater efficiency and greater power-handling capabilities to replace the rectangular waveguides. Two of these circular systems, at the 5-kG second-harmonic heating locations, have a total transmission efficiency of >90%. The two systems at the 10-kG fundamental heating locations have a total transmission efficiency of 80%. The difference in efficiency is due to the additional components required to launch the microwaves in the desired orientation and polarization with respect to magnetic-field lines at the 10-kG points. These systems handle the total power available from each gyrotron but do not have the arcing limitation problem of the rectangular waveguide. Each system requires several complex components. The overall physical layout and the design considerations for the rectangular and circular waveguide components are described here

  20. Organization and performance of the neutral beam system for the Tandem Mirror Experiment-Upgrade (TMX-U)

    International Nuclear Information System (INIS)

    The Tandem Mirror Experiment-Upgrade (TMX-U) at Lawrence Livermore National Laboratory (LLNL) uses 24 neutral-beam injectors to heat and fuel the experimental plasmas. This system is unique because TMX-U operates four times more injectors than any other fusion experiment. These injectors deliver an average of 50 A (accel) at 17 keV for 75 ms. Source conditioning time has been reduced to approximately four days for the entire system after extended machine air cycles. TMX-U is also unique because it has 35 usable injector assemblies for the 24 power systems. This quantity of injectors makes possible the development of new hardware and injector modifications, and the reconditioning of damaged sources without affecting machine operation. Efficient operation of a system of this size requires coordinated interaction between the injector service groups and the physics organization. We describe the current state of TMX-U performance and the aspects of group interaction essential to a project of this size

  1. Tandem mirror experiment-upgrade neutral beam test stand: a powerful tool for development and quality assurance

    International Nuclear Information System (INIS)

    During construction of the Tandem Mirror Experiment-Upgrade (TMX-U), we assembled a test stand to develop electronics for the neutral beam system. In the first six months of test stand use we operated a few neutral beam injector modules and directed considerable effort toward improving the electronic system. As system development progressed, our focus turned toward improving the injector modules themselves. The test stand has proved to be the largest single contributor to the successful operation of neutral beams on TMX-U, primarily because it provides quality assurance andd development capability in conjunction with the scheduled activities of the main experiment. This support falls into five major categories: (1) electronics development, (2) operator training, (3) injector module testing and characterization, (4) injector module improvements, and (5) physics improvements (through areas affected by injector operation). Normal day-to-day operation of the test stand comes under the third category, testing and characterization, and comprises our final quality assurance activity for newly assembled or repaired modules before they are installed on TMX-U

  2. Tandem Mirror Experiment-Upgrade neutral beam test stand: A powerful tool for development and quality assurance

    International Nuclear Information System (INIS)

    During construction of the Tandem Mirror Experiment-Upgrade (TMX-U), a test stand was assembled to develop electronics for the neutral beam system. In the first six months of test stand use the authors operated a few neutral beam injector modules and directed considerable effort toward improving the electronic system. As system development progressed, the focus turned toward improving the injector modules themselves. The test stand has proved to be the largest single contributor to the successful operation of neutral beams on TMX-U, primarily because it provides quality assurance and development capability in conjunction with the scheduled activities of the main experiment. This support falls into five major categories: (1) electronics development, (2) operator training, (3) injector module testing and characterization, (4) injector module improvements, and (5) physics improvements (through areas affected by injector operation). Normal day-to-day operation of the test stand comes under the third category, testing and characterization, and comprises the final quality assurance activity for newly assembled or repaired modules before they are installed on TMX-U. They have also used the test stand to perform a series of physics experiments, including: reducing gas flow through valve and arc chamber characterization, reducing impurities by titanium gettering, and reducing streaming gas using apertures and collisional gas dynamics

  3. Metal-oxide insulating materials for an 18T resistive insert coil for a tandem mirror fusion reactor

    International Nuclear Information System (INIS)

    18- to 30-tesla solenoids are used in the end cell of a tandem mirror reactor to prevent plasma from leaking out of the central reaction chamber. Superconductors can carry current only up to 16 tesla, so the solenoid would be a hybrid that is part superconducting and part normal conducting. The normal conducting part is water-cooled coil insert that is subjected to intense neutron irradiation. Organic electrical insulators would break down under these radiation conditions, losing both mechanical and dielectric strength. In order to alleviate this problem, we developed and tested three possibilities for an electrical insulation for a double pancake magnet design configuration. We (1) tested thin anodized strips of four metal alloys under simulated insulator load and slippage conditions, (2) co-wound and tested strips of anodized aluminum and titanium with the copper conductur, and (3) ion-vapor deposited and anodized a coating of aluminum on titanium, then tested this composite. This paper records the results, conclusions, and recommendations of our efforts. (author). 2 refs.; 1 fig.; 3 tabs

  4. Neutronic evaluation of fissile fuel breeding blankets for the fission-suppressed Tandem-Mirror Hybrid Reactor

    International Nuclear Information System (INIS)

    A computational study was performed on the blanket design of the Lawrence Livermore National Laboratory (LLNL) fission-suppressed Tandem Mirror Hybrid Reactor (TMHR) to qualify the methods and data bases available at Oak Ridge National Laboratory (ORNL) for use in analyzing the neutronic performance of fissile fuel breeding blankets. The eventual goal of the study was to establish the capability for analysis and optimization of advanced fissile fuel production blanket designs. Discrete ordinates radiation transport calculations were performed in one-dimensional cylindrical geometry to obtain the blanket spatial distribution and energy spectra of the neutron and gamma-ray fluxes resulting from the monoenergetic (14.1 MeV) fusion first wall source. Key macroscopic cross sections of the blanket materials were then folded with the flux spectra to obtain reaction rates critical to evaluating blanket feasibility. Finally, a time-dependent depletion analysis was performed to evaluate the blanket performance during equilibrium cycle conditions. The results of the study are presented both as graphs and tables

  5. X-ray detection system development for tandem mirror experiment upgrade (TMX-U): hardware and software

    International Nuclear Information System (INIS)

    This x-ray detection system measures the electron Bremsstrahlung spectrum from the Tandem Mirror Experiment-Upgrade (TMX-U). From this spectrum, we can calculate the electron temperature. The low energy portion of the spectrum (0.5 to 40 keV) is measured by a liquid-nitrogen-cooled, lithium-drifted silicon detector. The higher energy spectrometer uses an intrinsic germanium detector to accommodate the 100 to 200 keV spectra. The system proceeds as follows. The preamplified detector signals are digitized by a high-speed A-to-D converter located in a Computer Automated Measurement and Control (CAMAC) crate. The data is then stored in a histogramming memory via a data router. The CAMAC crate interfaces with a local desktop computer or the main data acquisition computer that stores the data. The software sets up the modules, acquires the energy spectra (with sample times as short as 2 ms) and plots it. Up to 40 time-resolved spectra are available during one plasma cycle. The actual module configuration, CAMAC interfacing and software that runs the system are the subjects of this paper

  6. X-ray imaging studies of electron cyclotron microwave-heated plasmas in the Tandem Mirror Experiment-Upgrade

    International Nuclear Information System (INIS)

    An x-ray pinhole camera designed to efficiently detect photons with energies between 5 and 250 keV was built to image bremsstrahlung emission from a microwave-heated hot electron plasma. This plasma is formed at one of the thermal barrier locations in the Tandem Experiment-Upgrade at Lawrence Livermore National Laboratory. The instrument consists of a lead aperture, an x-ray converter in the form of a sodium-activated cesium iodide scintillator, light intensifier electronics, and a recording medium that may either be high speed film or a CCD array. The nominal spatial and temporal resolutions are one part in 40 and 17 msec, respectively. The component requirements for optimum performance were determined both analytically and by computer simulation, and were verified experimentally. The details of these results are presented. The instrument has been used to measure x-ray emission from the TMX-U west end cell. Data acquired with the x-ray camera has allowed us to infer the temporal evolution of the mirror-trapped electron radial profile

  7. Investigation of auxiliary heating in tandem mirrors and tokamaks and barrier cell pumping. Annual progress report, October 1, 1980 to December 31, 1981

    International Nuclear Information System (INIS)

    The research has focussed on physics questions concerned with ECRH heating in tandem mirror plugs, pumping of tandem mirror thermal barriers by drift orbits, ICRH heating in tokamaks, and bundle divertors. We have concluded that drift-orbit pumping of thermal barriers is not feasible because the azimuthal E Vector X B Vector drift limits the excursion of trapped ions from a flux surface. We have developed a three-dimensional weakly relativistic (T/sub e/ less than or equal to 50 keV) ray tracing and absorption code for electron cyclotron heating in tandem mirror plugs and barriers. Cases run for TMX, MFTF-B and reactors at T/sub e/ > 10 keV show that strong absorption per pass is present and a careful choice of wave frequency and launch angle is required to ensure wave penetration and absorption in the plasma core. In the area of ion cyclotron frequency range heating in tokamaks, a three-dimensional hot plasma ray tracing theory and code has been developed to handle rays launched from any poloidal angle in the tokamak cross section. Wave heating in the central strong absorption zones is currently being investigated using a full wave solution for the various heating regimes

  8. Application of structural-mechanics methods to the design of large tandem-mirror fusion devices (MFTF-B). Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Karpenko, V.N.; Ng, D.S.

    1985-08-15

    The Mirror Fusion Test Facility (MFTF-B) at Lawrence Livermore National Laboratory requires state-of-the-art structural-mechanics methods to deal with access constraints for plasma heating and diagnostics, alignment requirements, and load complexity and variety. Large interactive structures required an integrated analytical approach to achieve a reasonable level of overall system optimization. The Tandem Magnet Generator (TMG) creates a magnet configuration for the EFFI calculation of electromagnetic-field forces that, coupled with other loads, form the input loading to magnet and vessel finite-element models. The analytical results provide the data base for detailed design of magnet, vessel, foundation, and interaction effects. 13 refs.

  9. Tandem mirror theory workshop

    International Nuclear Information System (INIS)

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

  10. Magneto-hydrodynamically stable axisymmetric mirrorsa)

    Science.gov (United States)

    Ryutov, D. D.; Berk, H. L.; Cohen, B. I.; Molvik, A. W.; Simonen, T. C.

    2011-09-01

    Making axisymmetric mirrors magnetohydrodynamically (MHD) stable opens up exciting opportunities for using mirror devices as neutron sources, fusion-fission hybrids, and pure-fusion reactors. This is also of interest from a general physics standpoint (as it seemingly contradicts well-established criteria of curvature-driven instabilities). The axial symmetry allows for much simpler and more reliable designs of mirror-based fusion facilities than the well-known quadrupole mirror configurations. In this tutorial, after a summary of classical results, several techniques for achieving MHD stabilization of the axisymmetric mirrors are considered, in particular: (1) employing the favorable field-line curvature in the end tanks; (2) using the line-tying effect; (3) controlling the radial potential distribution; (4) imposing a divertor configuration on the solenoidal magnetic field; and (5) affecting the plasma dynamics by the ponderomotive force. Some illuminative theoretical approaches for understanding axisymmetric mirror stability are described. The applicability of the various stabilization techniques to axisymmetric mirrors as neutron sources, hybrids, and pure-fusion reactors are discussed; and the constraints on the plasma parameters are formulated.

  11. Microwave measurement test results of circular waveguide components for electron cyclotron resonant heating (ECRH) of the Tandem Mirror Experiment-Upgrade (TMX-U)

    International Nuclear Information System (INIS)

    Development of high-power components for electron cyclotron resonant heating (ECRH) applications requires extensive testing. In this paper we describe the high-power testing of various circular waveguide components designed for application on the Tandem Mirror Experiment-Upgrade (TMX-U). These include a 2.5-in. vacuum valve, polarizing reflectors, directional couplers, mode converters, and flexible waveguides. All of these components were tested to 200 kW power level with 40-ms pulses. Cold tests were used to determine field distribution. The techniques used in these tests are illustrated. The new high-power test facility at Lawrence Livermore National Laboratory (LLNL) is described and test procedures are discussed. We discuss the following test results: efficiency at high power of mode converters, comparison of high power vs low power for waveguide components, and full power tests of the waveguide system. We also explain the reasons behind selection of these systems for use on TMX-U

  12. Proposed tandem mirror research program for FY87 presented to the MFAC subcommittee on mirror research, July 8-9, 1986

    International Nuclear Information System (INIS)

    We have reexamined the goal of approx.1013 cm-3 central-cell density with end-plugging and reconfirmed its importance as a test of thermal barrier end-plugging performance in either Tara or TMX-U. We conclude that, when all factors are considered including the impact on other programs interlinked with LLNL in the present OFE budget, the lowest cost approach to have a fair chance to meet this goal is to extend Tara operation for the full FY87. Continuation of TMX-U operation in FY87, in addition to the full year of Tara operation, would greatly improve the chance of success. Continuation of the mirror program into FY88 and beyond would be based on an experimental program in TMX-U and Tara at a minimum budget level of $25M/y, with restart of MFTF-B requiring an increase in the national fusion budget. The experimental program to be investigated by TMX-U and Tara would include improvement in the mgnetic geometry (stability, beta limits, and transport), continued plug studies (longer pulse length, impurities, drift pumping, and ECH efficiency), and transport studies (chi/sub e/, fueling, and halo formation)

  13. Design scoping study of the 12T Yin-Yang magnet system for the Tandem Mirror Next Step (TMNS). Final report

    Energy Technology Data Exchange (ETDEWEB)

    1981-09-01

    The overall objective of this engineering study was to determine the feasibility of designing a Yin-Yang magnet capable of producing a peak field in the windings of 12T for the Tandem Mirror Next Step (TMNS) program. As part of this technical study, a rough order of magnitude (ROM) cost estimate of the winding for this magnet was undertaken. The preferred approach to the winding design of the TMNS plug coil utilizes innovative design concepts to meet the structural, electrical and thermodynamic requirements of the magnet system. Structurally, the coil is radially partitioned into four sections, preventing the accumulation of the radial loads and reacting them into the structural case. To safely dissipate the 13.34 GJ of energy stored in each Yin-Yang magnet, the winding has been electrically subdivided into parallel or nested coils, each having its own power supply and protection circuitry. This arrangement effectively divides the total stored energy of the coils into manageable subsystems. The windings are cooled with superfluid helium II, operated at 1.8K and 1.2 atmospheres. The superior cooling capabilities of helium II have enabled the overall winding envelope to be minimized, providing a current density of 2367 A/CM/sup 2/, excluding substructure.

  14. Special topics reports for the reference tandem mirror fusion breeder: liquid metal MHD pressure drop effects in the packed bed blanket. Vol. 1

    International Nuclear Information System (INIS)

    Magnetohydrodynamic (MHD) effects which result from the use of liquid metal coolants in magnetic fusion reactors include the modification of flow profiles (including the suppression of turbulence) and increases in the primary loop pressure drop and the hydrostatic pressure at the first wall of the blanket. In the reference fission-suppressed tandem mirror fusion breeder design concept, flow profile modification is a relatively minor concern, but the MHD pressure drop in flowing the liquid lithium coolant through an annular packed bed of beryllium/thorium pebbles is directly related to the required first wall structure thickness. As such, it is a major concern which directly impacts fissile breeding efficiency. Consequently, an improved model for the packed bed pressure drop has been developed. By considering spacial averages of electric fields, currents, and fluid flow velocities the general equations have been reduced to simple expressions for the pressure drop. The averaging approach results in expressions for the pressure drop involving a constant which reflects details of the flow around the pebbles. Such details are difficult to assess analytically, and the constant may eventually have to be evaluated by experiment. However, an energy approach has been used in this study to bound the possible values of the constant, and thus the pressure drop. In anticipation that an experimental facility might be established to evaluate the undetermined constant as well as to address other uncertainties, a survey of existing facilities is presented

  15. Design scoping study of the 12T Yin-Yang magnet system for the Tandem Mirror Next Step (TMNS). Final report

    International Nuclear Information System (INIS)

    The overall objective of this engineering study was to determine the feasibility of designing a Yin-Yang magnet capable of producing a peak field in the windings of 12T for the Tandem Mirror Next Step (TMNS) program. As part of this technical study, a rough order of magnitude (ROM) cost estimate of the winding for this magnet was undertaken. The preferred approach to the winding design of the TMNS plug coil utilizes innovative design concepts to meet the structural, electrical and thermodynamic requirements of the magnet system. Structurally, the coil is radially partitioned into four sections, preventing the accumulation of the radial loads and reacting them into the structural case. To safely dissipate the 13.34 GJ of energy stored in each Yin-Yang magnet, the winding has been electrically subdivided into parallel or nested coils, each having its own power supply and protection circuitry. This arrangement effectively divides the total stored energy of the coils into manageable subsystems. The windings are cooled with superfluid helium II, operated at 1.8K and 1.2 atmospheres. The superior cooling capabilities of helium II have enabled the overall winding envelope to be minimized, providing a current density of 2367 A/CM2, excluding substructure

  16. Development of 1 MW gyrotron and progress of ECH system for the GAMMA 10 tandem mirror in Tsukuba

    International Nuclear Information System (INIS)

    High power gyrotrons with TE4,2 cavity at 28 GHz and with TE18,6 cavity and a diamond window at 77 GHz have been developed for GAMMA 10 and LHD in the joint program of NIFS and University of Tsukuba. The maximum outputs of 570 kW at 28 GHz and 1.1 MW at 77 GHz were obtained corresponding to each design. The operations of more than 750 kW for 5 sec. and 810 kW for 3.5 sec. were achieved in the developing tubes at 77 GHz, which is the first high power-long pulse result of the 77 GHz tube. The experimental simulation of the effect of the stray RF in the 28 GHz tube indicates the stray RF is the one of the major causes limiting gyrotron performance. The output of more than 1 MW with 40% oscillation efficiency is expected from the design of the next 28 GHz gyrotron for GAMMA 10. Installation of the polarizer in the transmission line enhanced the performance of the ECH system in GAMMA 10, that is the first result which clearly showed ∼100% X mode excitation is a key to design the efficient fundamental ECH system of strong field side injection in mirror devices. (author)

  17. Calibration experiments of 3He neutron detectors for analyzing neutron emissivity in the hot-ion mode on the GAMMA 10 tandem mirror

    Science.gov (United States)

    Kohagura, J.; Cho, T.; Hirata, M.; Watanabe, H.; Minami, R.; Numakura, T.; Yoshida, M.; Ito, H.; Tatematsu, Y.; Yatsu, K.; Miyoshi, S.; Ogura, K.; Kondoh, T.; Nishitani, T.; Kwon, M.; England, A. C.

    2003-03-01

    Under the international fusion cooperating research, 3He neutron detectors in the GAMMA 10 tandem mirror are calibrated by the use of a 252Cf spontaneous fission neutron source (8.96×104 n/s). The calibration experiments are carried out with a "rail system" placed along the magnetic axis of the GAMMA 10 central-cell region, where hot ions in the plasma experiments with the bulk temperatures of ˜10 keV are produced. As compared to a previous neutron monitoring system with a BF3 detector in GAMMA 10, the present 3He systems are designed with about two orders-of-magnitude higher neutron-counting efficiency for analyzing a neutron emissivity from the plasmas in a single plasma discharge alone. Two 3He systems are installed near the middle and the end of the central cell so as to identify the central-cell hot-ion axial profile. The filling pressure of 3He, the effective length, and the diameter of the detector are designed as 5 bar, 300 mm, and 50 mm, respectively. The detector output spectra are carefully analyzed by the use of a preamplifier, a shaping amplifier, as well as a multichannel analyzer for each 3He detector. In the present article, the neutron-counting data from the two 3He detectors due to the on-axis 252Cf scan are interpreted in terms of the d-2 intensity dependence (d being the distance between the detector and the neutron source) as well as the effects of the central-cell magnetic coils and the other machine structural components.

  18. Addition of trim coils to the Tandem Mirror Experiment Upgrade (TMX-U) magnet system to improve the magnetic field mapping

    International Nuclear Information System (INIS)

    The mapping of the magnetic flux bundle from the center cell to the Plasma Potential Control plates (PPC) on the end fan of the Tandem Mirror Experiment Upgrade (TMX-U), was improved by the addition of trim coils (12,000 amp-turns) on each side of each end fan next to the pump beam magnetic shields. The coils' axes are oriented perpendicular to the machine centerline. These coils made the necessary corrections to the field-line mapping, while keeping the field in the nearby pump beam magnetic shield below the saturation threshold. This paper briefly describes the problem, discusses the design as it evolved, and presents the results of the field testing. The disturbance to the field mapping and the appropriate corrections were determined using the code GFUN (a three dimensional electromagnetic field analysis code that includes the presence of permeable materials). The racetrack-shaped coils have dimensions of 1.5 feet by 3 feet and are powered by a renovated 600 kW Bart-Messing power supply controlled by the machine's magnet control system. The magnets were fabricated from polyimide-coated magnet wire. They are rated to 2000C, although in pulsed operation they rise only a few degrees centigrade. The coils are placed outside of the vacuum system, and thus are considerably simpler than the other machine magnets. The restraints are designed to withstand a force of 1000 pounds per coil and a turning moment of 1000 foot pounds. The calculated field strengths were verified on the machine by inserting a Hall probe along the axis. The perturbations to the neutral beam magnetic shields were also measured. A brief description of the improvement in the machine performance is also included

  19. Small mirror fusion reactors

    International Nuclear Information System (INIS)

    Basic requirements for the pilot plants are that they produce a net product and that they have a potential for commercial upgrade. We have investigated a small standard mirror fusion-fission hybrid, a two-component tandem mirror hybrid, and two versions of a field-reversed mirror fusion reactor--one a steady state, single cell reactor with a neutral beam-sustained plasma, the other a moving ring field-reversed mirror where the plasma passes through a reaction chamber with no energy addition

  20. The Status of Research Regarding Magnetic Mirrors as a Fusion Neutron Source or Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Simonen, T

    2008-12-23

    Experimental results, theory and innovative ideas now point with increased confidence to the possibility of a Gas Dynamic Trap (GDT) neutron source which would be on the path to an attractively simple Axisymmetric Tandem Mirror (ATM) power plant. Although magnetic mirror research was terminated in the US 20 years ago, experiments continued in Japan (Gamma 10) and Russia (GDT), with a very small US effort. This research has now yielded data, increased understanding, and generated ideas resulting in the new concepts described here. Early mirror research was carried out with circular axisymmetric magnets. These plasmas were MHD unstable due to the unfavorable magnetic curvature near the mid-plane. Then the minimum-B concept emerged in which the field line curvature was everywhere favorable and the plasma was situated in a MHD stable magnetic well (70% average beta in 2XII-B). The Ioffe-bar or baseball-coil became the standard for over 40 years. In the 1980's, driven by success with minimum-B stabilization and the control of ion cyclotron instabilities in PR6 and 2XII-B, mirrors were viewed as a potentially attractive concept with near-term advantages as a lower Q neutron source for applications such as a hybrid fission fuel factory or toxic waste burner. However there are down sides to the minimum-B geometry: coil construction is complex; restraining magnetic forces limit field strength and mirror ratios. Furthermore, the magnetic field lines have geodesic curvature which introduces resonant and neoclassical radial transport as observed in early tandem mirror experiments. So what now leads us to think that simple axisymmetric mirror plasmas can be stable? The Russian GDT experiment achieves on-axis 60% beta by peaking of the kinetic plasma pressure near the mirror throat (where the curvature is favorable) to counter-balance the average unfavorable mid-plane curvature. Then a modest augmentation of plasma pressure in the expander results in stability. The GDT

  1. The Status of Research Regarding Magnetic Mirrors as a Fusion Neutron Source or Power Plant

    International Nuclear Information System (INIS)

    Experimental results, theory and innovative ideas now point with increased confidence to the possibility of a Gas Dynamic Trap (GDT) neutron source which would be on the path to an attractively simple Axisymmetric Tandem Mirror (ATM) power plant. Although magnetic mirror research was terminated in the US 20 years ago, experiments continued in Japan (Gamma 10) and Russia (GDT), with a very small US effort. This research has now yielded data, increased understanding, and generated ideas resulting in the new concepts described here. Early mirror research was carried out with circular axisymmetric magnets. These plasmas were MHD unstable due to the unfavorable magnetic curvature near the mid-plane. Then the minimum-B concept emerged in which the field line curvature was everywhere favorable and the plasma was situated in a MHD stable magnetic well (70% average beta in 2XII-B). The Ioffe-bar or baseball-coil became the standard for over 40 years. In the 1980's, driven by success with minimum-B stabilization and the control of ion cyclotron instabilities in PR6 and 2XII-B, mirrors were viewed as a potentially attractive concept with near-term advantages as a lower Q neutron source for applications such as a hybrid fission fuel factory or toxic waste burner. However there are down sides to the minimum-B geometry: coil construction is complex; restraining magnetic forces limit field strength and mirror ratios. Furthermore, the magnetic field lines have geodesic curvature which introduces resonant and neoclassical radial transport as observed in early tandem mirror experiments. So what now leads us to think that simple axisymmetric mirror plasmas can be stable? The Russian GDT experiment achieves on-axis 60% beta by peaking of the kinetic plasma pressure near the mirror throat (where the curvature is favorable) to counter-balance the average unfavorable mid-plane curvature. Then a modest augmentation of plasma pressure in the expander results in stability. The GDT

  2. Superconducting magnets for mirror machines

    International Nuclear Information System (INIS)

    The simple mirror configuration, consisting of a long solenoid with increased field strength at the ends (magnetic mirrors), proved to be an unstable plasma container and was replaced by the minimum absolute value of B mirror configuration. The Yin-Yang minimum absolute value of B coil was chosen for the Mirror Fusion Test Facility (MFTF) experiment and recent conceptual designs of standard mirror reactors. For the multicell field-reversed mirror reactor concept we returned to the long solenoid configuration, augmented by normal copper mirror coils and Ioffe bars placed at the first wall radius to provide a shallow magnetic well for each field-reversed plasma layer. The central cell of the tandem mirror is also a long solenoid while the end plug cells require a minimum absolute value of B configuration

  3. Axisymmetric Grazing-Incidence Focusing Optics for Small-Angle Neutron Scattering

    OpenAIRE

    Liu, Dazhi; Gubarev, Mikhail V.; Resta, Giacomo; Ramsey, Brian D.; Moncton, David E.; Khaykovich, Boris

    2012-01-01

    We propose and design novel axisymmetric focusing mirrors, known as Wolter optics, for small-angle neutron scattering instruments. Ray-tracing simulations show that using the mirrors can result in more than an order-of-magnitude increase in the neutron flux reaching detectors, while decreasing the minimum wave vector transfer. Such mirrors are made of Ni using a mature technology. They can be coated with neutron supermirror multilayers, and multiple mirrors can be nested to improve their flux...

  4. Physics of mirror systems

    International Nuclear Information System (INIS)

    In recent years the emphasis in research on the magnetic mirror approach to fusion has been shifted to address what are essentially economically-motivated issues. The introduction of the Tandem Mirror idea solved in principal the problem of low Q (low fusion power gain) of mirror-based fusion systems. In order to optimize the tandem mirror idea from an economic standpoint, some important improvements have been suggested. These improvements include the thermal barrier idea of Baldwin and Logan and the axicell concept of Kesner. These new modifications introduce some special physics considerations. Among these are (1) The MHD stability properties of high energy electron components in the end cells; (2) The optimization of end-cell magnetic field configurations with the objective of minimizing equilibrium parallel currents; (3) The suppression of microstabilities by use of sloshing ion distributions. Following a brief outline of tandem mirror concepts, the above three topics are discussed, with illustrative examples taken from earlier work or from recent design studies

  5. Novel neutron focusing mirrors for compact neutron sources

    OpenAIRE

    Gubarev, M. V.; Zavlin, V. E.; Katz, R.; Resta, G.; Robertson, L; Crow, L.; Ramsey, B. D.; Khaykovich, Boris; Liu, DaZhi; Moncton, David E.

    2012-01-01

    We demonstrated neutron beam focusing and neutron imaging using axisymmetric optics, based on pairs of confocal ellipsoid and hyperboloid mirrors. Such systems, known as Wolter mirrors, are commonly used in x-ray telescopes. A system containing four nested Ni mirror pairs was implemented and tested by focusing a polychromatic neutron beam at the MIT Reactor and conducting an imaging experiment at HFIR. The major advantage of the Wolter mirrors is the possibility of nesting for large angular c...

  6. Helically linked mirror arrangement

    International Nuclear Information System (INIS)

    A scheme is described for helical linking of mirror sections, which endeavors to combine the better features of toroidal and mirror devices by eliminating the longitudinal loss of mirror machines, having moderately high average β and steady state operation. This scheme is aimed at a device, with closed magnetic surfaces having rotational transform for equilibrium, one or more axisymmetric straight sections for reduced radial loss, a simple geometrical axis for the links and an overall positive magnetic well depth for stability. We start by describing several other attempts at linking of mirror sections, made both in the past and the present. Then a description of our helically linked mirror scheme is given. This example has three identical straight sections connected by three sections having helical geometric axes. A theoretical analysis of the magnetic field and single-particle orbits in them leads to the conclusion that most of the passing particles would be confined in the device and they would have orbits independent of pitch angle under certain conditions. Numerical results are presented, which agree well with the theoretical results as far as passing particle orbits are concerned

  7. Axisymmetric multiwormholes revisited

    Science.gov (United States)

    Clément, Gérard

    2016-06-01

    The construction of stationary axisymmetric multiwormhole solutions to gravitating field theories admitting toroidal reductions to three-dimensional gravitating sigma models is reviewed. We show that, as in the multi-black hole case, strut singularities always appear in this construction, except for very special configurations with an odd number of centers. We also review the analytical continuation of the multicenter solution across the n cuts associated with the wormhole mouths. The resulting Riemann manifold has 2^n sheets interconnected by 2^{n-1}n wormholes. We find that the maximally extended multicenter solution can never be asymptotically locally flat in all the Riemann sheets.

  8. Axisymmetric multiwormholes revisited

    CERN Document Server

    Clément, Gérard

    2015-01-01

    The construction of stationary axisymmetric multiwormhole solutions to gravitating field theories admitting toroidal reductions to three-dimensional gravitating sigma models is reviewed. We show that, as in the multi-black hole case, strut singularities always appear in this construction, except for very special configurations with an odd number of centers. We also review the analytical continuation of the multicenter solution across the $n$ cuts associated with the wormhole mouths. The resulting Riemann manifold has $2^n$ sheets interconnected by $2^{n-1}n$ wormholes. We find that the maximally extended multicenter solution can never be asymptotically locally flat in all the Riemann sheets.

  9. Axisymmetric control in tokamaks

    International Nuclear Information System (INIS)

    Vertically elongated tokamak plasmas are intrinsically susceptible to vertical axisymmetric instabilities as a result of the quadrupole field which must be applied to produce the elongation. The present work analyzes the axisymmetric control necessary to stabilize elongated equilibria, with special application to the Alcator C-MOD tokamak. A rigid current-conserving filamentary plasma model is applied to Alcator C-MOD stability analysis, and limitations of the model are addressed. A more physically accurate nonrigid plasma model is developed using a perturbed equilibrium approach to estimate linearized plasma response to conductor current variations. This model includes novel flux conservation and vacuum vessel stabilization effects. It is found that the nonrigid model predicts significantly higher growth rates than predicted by the rigid model applied to the same equilibria. The nonrigid model is then applied to active control system design. Multivariable pole placement techniques are used to determine performance optimized control laws. Formalisms are developed for implementing and improving nominal feedback laws using the C-MOD digital-analog hybrid control system architecture. A proportional-derivative output observer which does not require solution of the nonlinear Ricatti equation is developed to help accomplish this implementation. The nonrigid flux conserving perturbed equilibrium plasma model indicates that equilibria with separatrix elongation of at least sep = 1.85 can be stabilized robustly with the present control architecture and conductor/sensor configuration

  10. Mirror agnosia.

    OpenAIRE

    Ramachandran, V. S.; Altschuler, E. L.; Hillyer, S

    1997-01-01

    Normal people rarely confuse the mirror image of an object with a real object so long as they realize they are looking into a mirror. We report a new neurological sign, 'mirror agnosia', following right parietal lesions in which this ability is severely compromised. We studied four right hemisphere stroke patients who had left visual field 'neglect'. i.e. they were indifferent to objects in their left visual field even though they were not blind. We then placed a vertical parasagittal mirror ...

  11. Einstein's Mirror

    Science.gov (United States)

    Gjurchinovski, Aleksandar; Skeparovski, Aleksandar

    2008-01-01

    Reflection of light from a plane mirror in uniform rectilinear motion is a century-old problem, intimately related to the foundations of special relativity. The problem was first investigated by Einstein in his famous 1905 paper by using the Lorentz transformations to switch from the mirror's rest frame to the frame where the mirror moves at a…

  12. Evolution of the mirror machine

    International Nuclear Information System (INIS)

    The history of the magnetic-mirror approach to a fusion reactor is primarily the history of our understanding and control of several crucial physics issues, coupled with progress in the technology of heating and confining a reacting plasma. The basic requirement of an MHD-stable plasma equilibrium was achieved following the early introduction of minimum-B multipolar magnetic fields. In refined form, the same magnetic-well principle carries over to our present experiments and to reactor designs. The higher frequency microinstabilities, arising from the non-Maxwellian particle distributions inherent in mirror machines, have gradually come under control as theoretical prescriptions for distribution functions have been applied in the experiments. Even with stability, the classical plasma leakage through the mirrors posed a serious question for reactor viability until the principle of electrostatic axial stoppering was applied in the tandem mirror configuration. Experiments to test this principle successfully demonstrated the substantial improvement in confinement predicted. Concurrent with advances in mirror plasma physics, development of both high-power neutral beam injectors and high-speed vacuum pumping techniques has played a crucial role in ongoing experiments. Together with superconducting magnets, cryogenic pumping, and high-power radiofrequency heating, these technologies have evolved to a level that extrapolates readily to meet the requirements of a tandem mirror fusion reactor

  13. Chiral mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Plum, Eric, E-mail: erp@orc.soton.ac.uk [Optoelectronics Research Centre and Centre for Photonic Metamaterials, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); Zheludev, Nikolay I., E-mail: niz@orc.soton.ac.uk [Optoelectronics Research Centre and Centre for Photonic Metamaterials, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); The Photonics Institute and Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore 637378 (Singapore)

    2015-06-01

    Mirrors are used in telescopes, microscopes, photo cameras, lasers, satellite dishes, and everywhere else, where redirection of electromagnetic radiation is required making them arguably the most important optical component. While conventional isotropic mirrors will reflect linear polarizations without change, the handedness of circularly polarized waves is reversed upon reflection. Here, we demonstrate a type of mirror reflecting one circular polarization without changing its handedness, while absorbing the other. The polarization-preserving mirror consists of a planar metasurface with a subwavelength pattern that cannot be superimposed with its mirror image without being lifted out of its plane, and a conventional mirror spaced by a fraction of the wavelength from the metasurface. Such mirrors enable circularly polarized lasers and Fabry-Pérot cavities with enhanced tunability, gyroscopic applications, polarization-sensitive detectors of electromagnetic waves, and can be used to enhance spectroscopies of chiral media.

  14. Three-Dimensional Electromagnetic High Frequency Axisymmetric Cavity Scars.

    Energy Technology Data Exchange (ETDEWEB)

    Warne, Larry Kevin; Jorgenson, Roy Eberhardt

    2014-10-01

    This report examines the localization of high frequency electromagnetic fi elds in three-dimensional axisymmetric cavities along periodic paths between opposing sides of the cavity. The cases where these orbits lead to unstable localized modes are known as scars. This report treats both the case where the opposing sides, or mirrors, are convex, where there are no interior foci, and the case where they are concave, leading to interior foci. The scalar problem is treated fi rst but the approximations required to treat the vector fi eld components are also examined. Particular att ention is focused on the normalization through the electromagnetic energy theorem. Both projections of the fi eld along the scarred orbit as well as point statistics are examined. Statistical comparisons are m ade with a numerical calculation of the scars run with an axisymmetric simulation. This axisymmetric cas eformstheoppositeextreme(wherethetwomirror radii at each end of the ray orbit are equal) from the two -dimensional solution examined previously (where one mirror radius is vastly di ff erent from the other). The enhancement of the fi eldontheorbitaxiscanbe larger here than in the two-dimensional case. Intentionally Left Blank

  15. Mirror matter

    OpenAIRE

    Ignatiev, A. Yu.; Volkas, R. R.

    2003-01-01

    One of the deepest unsolved puzzles of subatomic physics is why Nature prefers the left particles to the right ones. Mirror matter is an attempt to understand this mystery by assuming the existence of a "parallel''world where this preference is exactly opposite. Thus in the Universe consisting of the ordinary and the mirror matter the symmetry between the left and right is completely restored. Mirror matter is constrained to interact with us only very weakly. Still, its existence can be infer...

  16. Stability of Axisymmetric Liquid Bridges

    CERN Document Server

    Rubinstein, Boris

    2016-01-01

    We study stability of axisymmetric liquid bridges between two axisymmetric solid bodies in the absence of gravity under arbitrary asymmetric perturbations which are expanded into a set of angular Fourier modes. We determine the stability region boundary for every angular mode in case of both fixed and free contact lines. Application of this approach allows us to demonstrate existence of stable convex nodoid menisci between two spheres.

  17. Tandem mirror reactor with thermal barriers

    International Nuclear Information System (INIS)

    This report gives detailed information in the form of the following chapters: (1) overview, (2) plasma physics, (3) magnets, (4) end-plug neutral beams, (5) barrier pump neutral beams, (6) ecr heating, (7) plasma direct converter, and (8) central cell

  18. Phaedrus tandem mirror. Status report, Spring 1983

    International Nuclear Information System (INIS)

    During the spring of 1983, the Phaedrus group undertook a major up to air to improve diagnostic capabilities, modify RF antennas and clean up the inner vacuum surfaces of accumulated getter material. This time was also used to analyze more thoroughly our present data base and correlate it with relevant theoretical predictions. A neutral beam build up code has been developed to model RF central stream trapping and heating, neutral gas charge exchange losses with finite gyroradius effects, and beam aiming sensitivity. MHD stability of the central cell stand alone operation has been explained by a radial ponderomotive force which opposes the centrifugal force due to bad field line curvature. First drafts of research papers on RF trapping, electron cyclotron heating, the stand alone mode, and MHD instability studies were completed. All of these papers require more experiments to tie up loose ends but the loose ends were identified more clearly by this process. The remainder of this report will be organized by experimental area, describing in limited detail the status of current research, recent modifications to diagnostic and machine hardware and immediate future experimental objectives

  19. Mirror Advanced Reactor Study (MARS) final report summary

    International Nuclear Information System (INIS)

    The Mirror Advanced Reactor Study (MARS) has resulted in an overview of a first-generation tandem mirror reactor. The central cell fusion plasma is self-sustained by alpha heating (ignition), while electron-cyclotron resonance heating and negative ion beams maintain the electrostatic confining potentials in the end plugs. Plug injection power is reduced by the use of high-field choke coils and thermal barriers, concepts to be tested in the Tandem Mirror Experiment-Upgrade (TMX-U) and Mirror Fusion Test Facility (MFTF-B) at Lawrence Livermore National Laboratory

  20. Axisymmetric annular curtain stability

    International Nuclear Information System (INIS)

    A temporal stability analysis was carried out to investigate the stability of an axially moving viscous annular liquid jet subject to axisymmetric disturbances in surrounding co-flowing viscous gas media. We investigated in this study the effects of inertia, surface tension, the gas-to-liquid density ratio, the inner-to-outer radius ratio and the gas-to-liquid viscosity ratio on the stability of the jet. With an increase in inertia, the growth rate of the unstable disturbances is found to increase. The dominant (or most unstable) wavenumber decreases with increasing Reynolds number for larger values of the gas-to-liquid viscosity ratio. However, an opposite tendency for the most unstable wavenumber is predicted for small viscosity ratio in the same inertia range. The surrounding gas density, in the presence of viscosity, always reduces the growth rate, hence stabilizing the flow. There exists a critical value of the density ratio above which the flow becomes stable for very small viscosity ratio, whereas for large viscosity ratio, no stable flow appears in the same range of the density ratio. The curvature has a significant destabilizing effect on the thin annular jet, whereas for a relatively thick jet, the maximum growth rate decreases as the inner radius increases, irrespective of the surrounding gas viscosity. The degree of instability increases with Weber number for a relatively large viscosity ratio. In contrast, for small viscosity ratio, the growth rate exhibits a dramatic dependence on the surface tension. There is a small Weber number range, which depends on the viscosity ratio, where the flow is stable. The viscosity ratio always stabilizes the flow. However, the dominant wavenumber increases with increasing viscosity ratio. The range of unstable wavenumbers is affected only by the curvature effect. (paper)

  1. Magic Mirrors

    Science.gov (United States)

    Mills, Allan

    2011-01-01

    "Magic mirrors" were so named because, when they were positioned to throw a reflected patch of sunlight on a nearby wall, this area contained an outline of a design cast on the back of the (bronze) mirror. Investigations begun in the 19th century showed that this was a response to heavy localized pressures exerted on the face of the thin mirror…

  2. Magnetic mirror fusion: status and prospects

    International Nuclear Information System (INIS)

    Two improved mirror systems, the tandem mirror (TM) and the field-reversed mirror (FRM) are being intensively studied. The twin practical aims of these studies: to improve the economic prospects for mirror fusion power plants and to reduce the size and/or complexity of such plants relative to earlier approaches to magnetic fusion. While at the present time the program emphasis is still strongly oriented toward answering scientific questions, the emphasis is shifting as the data accumulates and as larger facilities - ones with a heavy technological and engineering orientation - are being prepared. The experimental and theoretical progress that led to the new look in mirror fusion research is briefly reviewed, the new TM and the FRM ideas are outlined, and the projected future course of mirror fusion research is discussed

  3. Magnetic mirror fusion: status and prospects

    Energy Technology Data Exchange (ETDEWEB)

    Post, R.F.

    1980-02-11

    Two improved mirror systems, the tandem mirror (TM) and the field-reversed mirror (FRM) are being intensively studied. The twin practical aims of these studies: to improve the economic prospects for mirror fusion power plants and to reduce the size and/or complexity of such plants relative to earlier approaches to magnetic fusion. While at the present time the program emphasis is still strongly oriented toward answering scientific questions, the emphasis is shifting as the data accumulates and as larger facilities - ones with a heavy technological and engineering orientation - are being prepared. The experimental and theoretical progress that led to the new look in mirror fusion research is briefly reviewed, the new TM and the FRM ideas are outlined, and the projected future course of mirror fusion research is discussed.

  4. Mirror Advanced Reactor Study interim design report

    International Nuclear Information System (INIS)

    The status of the design of a tenth-of-a-kind commercial tandem-mirror fusion reactor is described at the midpoint of a two-year study. When completed, the design is to serve as a strategic goal for the mirror fusion program. The main objectives of the Mirror Advanced Reactor Study (MARS) are: (1) to design an attractive tandem-mirror fusion reactor producing electricity and synfuels (in alternate versions), (2) to identify key development and technology needs, and (3) to exploit the potential of fusion for safety, low activation, and simple disposal of radioactive waste. In the first year we have emphasized physics and engineering of the central cell and physics of the end cell. Design optimization and trade studies are continuing, and we expect additional modifications in the end cells to further improve the performance of the final design

  5. Mirror Advanced Reactor Study interim design report

    Energy Technology Data Exchange (ETDEWEB)

    1983-04-01

    The status of the design of a tenth-of-a-kind commercial tandem-mirror fusion reactor is described at the midpoint of a two-year study. When completed, the design is to serve as a strategic goal for the mirror fusion program. The main objectives of the Mirror Advanced Reactor Study (MARS) are: (1) to design an attractive tandem-mirror fusion reactor producing electricity and synfuels (in alternate versions), (2) to identify key development and technology needs, and (3) to exploit the potential of fusion for safety, low activation, and simple disposal of radioactive waste. In the first year we have emphasized physics and engineering of the central cell and physics of the end cell. Design optimization and trade studies are continuing, and we expect additional modifications in the end cells to further improve the performance of the final design.

  6. TASKA - Tandem Spiegelmaschine Karlsruhe. Vol. 2

    International Nuclear Information System (INIS)

    TASKA (Tandem Spiegelmaschine Karlsruhe) is a near term engineering test facility based on a tandem mirror concept with thermal barriers. The main objectives of this study were to develop a preconceptual design of a facility that could provide engineering design information for a Demonstration Fusion Power Reactor. Thus TASKA has to serve as testbed for technologies of plasma engineering, superconducting magnets, materials, plasma heating, breeding and test blankets, tritium technology, and remote handling. (orig.)

  7. TASKA - Tandem Spiegelmaschine Karlsruhe. Vol. 1

    International Nuclear Information System (INIS)

    TASKA (Tandem Spiegelmaschine Karlsruhe) is a near term engineering test facility based on a tandem mirror concept with thermal barriers. The main objectives of this study were to develop a preconceptual design of a facility that could provide engineering design information for a Demonstration Fusion Power Reactor. Thus TASKA has to serve as testbed for technologies of plasma engineering, superconducting magnets, materials, plasma heating, breeding and test blankets, tritium technology, and remote handling. (orig.)

  8. Mirror, mirror on the wall

    CERN Multimedia

    2005-01-01

    RICH 2, one of the two Ring Imaging Cherenkov detectors of the LHCb experiment, is being prepared to join the other detector elements ready for the first proton-proton collisions at LHC. The mirrors of the RICH2 detector are meticulously assembled in a clean room.In a large dark room, men in white move around an immense structure some 7 metres high, 10 metres wide and nearly 2.5 metres deep. Apparently effortlessly, they are installing the two large high-precision spherical mirrors. These mirrors will focus Cherenkov light, created by the charged particles that will traverse this detector, onto the photon detectors. Each spherical mirror wall is made up of facets like a fly's eye. Twenty-eight individual thin glass mirrors will all point to the same point in space to within a few micro-radians. The development of these mirrors has been technically demanding : Ideally they should be massless, sturdy, precise and have high reflectivity. In practice, though not massless, they are made from a mere 6 mm thin gl...

  9. Options for axisymmetric operation of MFTF-B

    International Nuclear Information System (INIS)

    The flexibility of MFTF-B for axisymmetric experiments has been investigated. Interhcanging the axicell coils and increasing their separation results in an axisymmetric plug cell with 12:1 and 6:1 inner and outer mirror ratios, respectively. For axisymmetric operation, the sloshing-ion neutral beams, ECRH gyrotrons, and the pumping system would be moved to the axicell. Stabilization by E-rings could be explored in this configuration. With the addition of octopole magnets, off-axis multipole stabilization could also be tested. Operating points for octopole and E-ring-stabilized configurations with properties similar to those of the quadrupole MFTF-B, namely T/sub ic/ = 10 - 15 keV and n/sub c/ approx. = 3 x 1013 cm-3, have been obtained. Because of the negligible radial transport of central-cell ions, the required neutral-beam power in the central cell has been dramatically reduced. In addition, because MHD stabilization is achieved by off-axis hot electrons in both cases, much lower barrier beta is possible, which aids in reducing the barrier ECRH power. Total ECRH power in the end cell is projected to be approx. =1 MW. Possible operating points for both octopole and E-ring configurations are described along with the stability considerations involved

  10. Mirror Technology

    Science.gov (United States)

    1992-01-01

    Under a NASA contract, MI-CVD developed a process for producing bulk silicon carbide by means of a chemical vapor deposition process. The technology allows growth of a high purity material with superior mechanical/thermal properties and high polishability - ideal for mirror applications. The company employed the technology to develop three research mirrors for NASA Langley and is now marketing it as CVD SILICON CARBIDE. Its advantages include light weight, thermal stability and high reflectivity. The material has nuclear research facility applications and is of interest to industrial users of high power lasers.

  11. Experiments in axisymmetric supersonic jets

    Science.gov (United States)

    Moore, Cyrille Dennis

    An experimental study of the effects of exit Mach number and density ratio on the development of axisymmetric jets is described in this thesis. Jet exit Mach numbers of 1.41, 2.0, and 3.0, were studied for jets of helium, argon, and nitrogen. The jets exit into a gas at rest (velocity ratio = 0), in order to better isolate the effects of compressibility and density ratio. Density ratios vary from 0.23 to 5.5.In order to generate shock free-jets, unique nozzles were designed and constructed for each gas and Mach number combination. A plating method for the construction of the nozzles was developed to ensure high-accuracy and a good surface finish at a cost significantly less than direct-machining techniques.The spreading rate of the jet for several downstream locations is measured with a pitot probe. Centerline data are used to characterise the length of the potential core of the jet, which correlates well with the relative spreading rates. Limited frequency data is obtained through the use of piezo-resistive pressure probes. This method is promising for flows that are not conducive to hot-wire probes.Spark shadography is used to visualize both the mean and instantaneous flow, with the minimum spark time being 20 nanoseconds. The convection velocity of large-scale disturbances is estimated from the visible Mach-type acoustic waves emanating from the jet.For a wide range of jet Mach and Reynolds numbers, the convection velocity of the large scale disturbances in the potential core region of the jet is approximately 0.8 times the jet velocity, the approximate velocity of the first helical instability mode of the jet.The main objectives of the present work were to investigate the effects of compressibility and density on the initial development of the axisymmetric jet. Although the data are not sufficient to determine if the convective Mach number concept used in 2-d shear layer research will work in the case of an axisymmetric jet, it is clear that the axisymmetric

  12. Mirror monochromator

    Energy Technology Data Exchange (ETDEWEB)

    Mankos, Marian [Electron Optica, Inc., Palo Alto, CA (United States); Shadman, Khashayar [Electron Optica, Inc., Palo Alto, CA (United States)

    2014-12-02

    In this SBIR project, Electron Optica, Inc. (EOI) is developing a mirror electron monochromator (MirrorChrom) attachment to new and retrofitted electron microscopes (EMs) for improving the energy resolution of the EM from the characteristic range of 0.2-0.5 eV to the range of 10-50 meV. This improvement will enhance the characterization of materials by imaging and spectroscopy. In particular, the monochromator will refine the energy spectra characterizing materials, as obtained from transmission EMs [TEMs] fitted with electron spectrometers, and it will increase the spatial resolution of the images of materials taken with scanning EMs (SEMs) operated at low voltages. EOI’s MirrorChrom technology utilizes a magnetic prism to simultaneously deflect the electron beam off the axis of the microscope column by 90° and disperse the electrons in proportional to their energies into a module with an electron mirror and a knife-edge. The knife-edge cuts off the tails of the energy distribution to reduce the energy spread of the electrons that are reflected, and subsequently deflected, back into the microscope column. The knife-edge is less prone to contamination, and thereby charging, than the conventional slits used in existing monochromators, which improves the reliability and stability of the module. The overall design of the MirrorChrom exploits the symmetry inherent in reversing the electron trajectory in order to maintain the beam brightness – a parameter that impacts how well the electron beam can be focused downstream onto a sample. During phase I, EOI drafted a set of candidate monochromator architectures and evaluated the trade-offs between energy resolution and beam current to achieve the optimum design for three particular applications with market potential: increasing the spatial resolution of low voltage SEMs, increasing the energy resolution of low voltage TEMs (beam energy of 5-20 keV), and increasing the energy resolution of conventional TEMs (beam

  13. Stability of the field-reversed mirror

    International Nuclear Information System (INIS)

    The stability of a field reversed mirror plasma configuration is studied with an energy principle derived from the Vlasov equation. Because of finite orbit effects, the stability properties of a field-reversed mirror are different from the stability properties of similar magnetohydrodynamic equilibria. The Vlasov energy principle developed here is applied to a computer simulation of an axisymmetric field-reversed mirror state. It has been possible to prove that the l = 0 modes, called tearing modes, satisfy a sufficient condition for stability. Precessional modes, with l = 1, 2, are found to be unstable at low growth rate. This suggests possible turbulent behavior (Bohm confinement) in the experimental devices aiming at field reversal. Techniques for suppressing these instabilities are outlined, and the applicability of the Vlasov energy principle to more complicated equilibrium models is shown

  14. Tandem accelerators

    International Nuclear Information System (INIS)

    After the installation of Ti-acceleration tubes and substantial modifications and additions to the EN tandem accelerator the performance of the machine has stabilized. The voltage behaviour of the tubes obviously improves as conditioning times necessary to run up to 6 MV decrease. A gridded lens has been added at the entrance of the first acceleration tube, and a second foil stripper is now installed in the short dead section between the high-energy tubes. The MP tandem also has been running stably during most of the year. However, beam instabilities originating from the last tube section and wear problems at the low-energy set of pelletron-chains caused some loss of beam time. During the fall, one set of pelletron charging chains has to be replaced after 49,000 hours of operation. In the course of the year, the MP and the EN tandem accelerators finished their 100,000th and 150,000th hours of operations, respectively. Preparations for the installation of the 3 MV negative heavy ion injector for the MP are progressing steadily. External beam transport, terminal ion optics, and data acquisition and control systems are to a major extent completed; the integration of the terminal power supplies has started. After the final assembly of the accelerator column structure, first voltage runs can be performed. (orig.)

  15. Axisymmetric Coanda-Assisted Vectoring

    OpenAIRE

    Allen, Dustin S

    2008-01-01

    An examination of parameters affecting the control of a jet vectoring technique used in the Coanda-assisted Spray Manipulation (CSM) is presented. The CSM makes use of an enhanced Coanda effect on axisymmetric geometries through the interaction of a high volume primary jet flowing through the center of a collar and a secondary high-momentum jet parallel to the first and adjacent to the convex collar. The control jet attaches to the convex wall and vectors according to known Coanda effect prin...

  16. Stability of Axisymmetric Pendular Rings

    CERN Document Server

    Fel, Leonid G

    2014-01-01

    Based on the Weierstrass representation of second variation we develop a non-spectral theory of stability for isoperimetric problem with minimized and constrained two-dimensional functionals of general type and free endpoints allowed to move along two given planar curves. We apply this theory to the axisymmetric pendular ring between two solid bodies without gravity to determine the stability of menisci with free contact lines. For catenoid and cylinder menisci and different solid shapes we determine the stability domain. The other menisci (unduloid, nodoid and sphere) are considered in a simple setup between two plates. We find the existence conditions of stable unduloid menisci with and without inflection points.

  17. Mirror advanced reactor study (MARS)

    International Nuclear Information System (INIS)

    The agenda for the meeting is as follows: (1) basic Tandem Mirror approach, (2) baseline design, (3) transition and Yin-Yang coils, (4) drift pump physics, (5) drift pump coil, (6) Fokker-Planck analysis, (7) ignition-alpha pumping, (8) neutral beam status, (9) axicell layout, (10) axicell radiation levels, (11) ICRH system, (12) central cell cost optimization, (13) central cell coil design, (14) gridless direct converter, (15) direct converter directions, (16) end cell structure, (17) corrosion-double wall HX, (18) central cell maintenance, (19) radioactivity, (20) PbLi blanket design, and (21) MARS schedule

  18. Magnetic-mirror principle as applied to fusion research

    International Nuclear Information System (INIS)

    A tutorial account is given of the key physics issues in the confinement of high temperature plasma in magnetic mirror systems. The role of adiabatic invariants and particle drifts and their relationship to equilibrium and stability are discussed, in the context of the various forms of mirror field geometry. Collisional effects and the development and the control of ambipolar potentials are reviewed. The topic of microinstabilities is discussed together with the means for their control. The properties and advantages for fusion power purposes of various special embodiments of the mirror idea, including tandem mirrors, are discussed

  19. Magnetic mirror fusion-fission early history and applicability to other systems

    International Nuclear Information System (INIS)

    In the mid 1970s to mid 1980s the mirror program was stuck with a concept, the Standard Mirror that was Q ∼ 1 where Q=Pfusion/Pinjection. Heroic efforts were put into hybridizing thinking added energy and fuel sales would make a commercial product. At the same time the tokamak was thought to allow ignition and ultrahigh Q values of 20 or even higher. There was an effort to use neutral beams to drive the tokamak just like the mirror machines were driven in which case the Q value plunged to a few, however this was thought to be achievable decades earlier than the high Q versions. Meanwhile current drive and other features of the tokamak have seen the projected Q values come down to the range of 10. Meanwhile the mirror program got Q enhancement into high gear and various tandem mirrors projected Q values up towards 10 and with advanced features over 10 with axi-symmetric magnets (See R. F. Post papers), however the experimental program is all but non-existent. Meanwhile, the gas dynamic trap mirror system which is present day state-of-the-art can with low risk produce Q of ∼0.1 useful for a low risk, low cost neutron source for materials development useful for the development of materials for all fusion concepts (see Simonen white paper: 'A Physics-Based Strategy to Develop a Mirror Fusion-Fission Hybrid' and D.D. Ryutov, 'Axisymmetric MHD-stable mirror as a neutron source and a driver for a fusion-fission hybrid'). Many early hybrid designs with multi-disciplinary teams were carried out in great detail for the mirror system with its axi-symmetric blanket modules. It is recognized that most of these designs are adaptable to tokamak or inertial fusion geometry. When Q is low (1 to 2) economics gives a large economic penalty for high recirculating power. These early studies covered the three design types: Power production, fuel production and waste burning. All three had their place but power production fell away because every study showed fusion machines that were

  20. Properties of High Beta, Quasi-Axisymmetric NCSX Stellarator Configurations

    International Nuclear Information System (INIS)

    Quasi-axisymmetry, external kinks and ballooning stability are studied with respect to the plasma shaping and the variation in the pressure and current profiles for NCSX. We show that while the kink stability may require a delicate boundary shaping, most quasi-axisymmetry may be achieved using a few low order modes that eliminate the large mirror fields arising partly from boundary shaping for the kink stability. In addition, we demonstrate that the kink and ballooning instability may be improved in the NCSX configurations by a more peaked pressure profile or a broader current profile. Finally, we show numerically that it is possible to construct a quasi-axisymmetric configuration that is stable to the external kink at all current levels for which the edge rotational transform is less than 0.5

  1. Properties of High Beta, Quasi-Axisymmetric NCSX Stellarator Configurations

    International Nuclear Information System (INIS)

    Quasi-axisymmetry, external kinks and ballooning stability are studied with respect to the plasma shaping and variation in the pressure and current profiles for NCSX. We show that while the kink stability may require a delicate boundary shaping, most quasi-axisymmetry may be achieved using a few low order modes that eliminate the large mirror fields arising partly from boundary shaping for the kink stability. In addition, we demonstrate that the kink and ballooning instability may be improved in the NCSX configurations by a more peaked pressure profile or a broader current profile. Finally, we show numerically that it is possible to construct a quasi-axisymmetric configuration that is stable to the external kink at all current levels for which the edge rotational transform is less than 0.5

  2. Streamline topology of axisymmetric flows

    DEFF Research Database (Denmark)

    Brøns, Morten

    , which to the authors knowledge has not been used systematically to high orders in topological fluid mechanics. We compare the general results with experimental and computational results on the Vogel-Ronneberg flow. We show that the topology changes observed when recirculating bubbles on the vortex axis......Topological fluid mechanics in the sense of the present paper is the study and classification of flow patterns close to a critical point. Here we discuss the topology of steady viscous incompressible axisymmetric flows in the vicinity of the axis. Following previous studies the velocity field $v......$ is expanded in a Taylor series at a point on the axis, and the expansion coefficients are considered as bifurcation parameters. After a normal form transformation we easily obtain the most common bifurcations of the flow patterns. The use of non-linear normal forms provide a gross simplification...

  3. Beam splitting mirror for advanced photon source sector 34

    International Nuclear Information System (INIS)

    The insertion device beamline at APS sector 34 is intended for tandem operation of two, high brilliance, experimental stations. Each station will require only a small fraction of the total cross-sectional area of the undulator beam, allowing both to operate simultaneously without compromise. A Coherent X-ray Diffraction (CXD) station will be supplied with pink beam from a horizontally reflecting, beam splitting mirror, while a Micro-Focus Diffraction (MFD) station will operate with white beam that passes beside the mirror. Use of a mirror as a beam splitter requires good thermal and mechanical stability from the mirror and its associated positioning system. The mirror substrate is liquid nitrogen cooled to minimize the thermal bump and increase its thermal conductivity. The principal motions of the mirror (2 translations, 2 rotations) are handled outside the chamber and passed into vacuum via two sets of bellows

  4. Mirror Fusion Test Facility: an intermediate device to a mirror fusion reactor

    International Nuclear Information System (INIS)

    The Mirror Fusion Test Facility (MFTF-B) now under construction at Lawrence Livermore National Laboratory represents more than an order-of-magnitude step from earlier magnetic-mirror experiments toward a future mirror fusion reactor. In fact, when the device begins operating in 1986, the Lawson criteria of ntau = 1014 cm-3.s will almost be achieved for D-T equivalent operation, thus signifying scientific breakeven. Major steps have been taken to develop MFTF-B technologies for tandem mirrors. Steady-state, high-field, superconducting magnets at reactor-revelant scales are used in the machine. The 30-s beam pulses, ECRH, and ICRH will also introduce steady-state technologies in those systems

  5. Axisymmetric Coanda-assisted vectoring

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Dustin; Smith, Barton L. [Utah State University, Mechanical and Aerospace Engineering, Logan, UT (United States)

    2009-01-15

    An experimental demonstration of a jet vectoring technique used in our novel spray method called Coanda-assisted Spray Manipulation (CSM) is presented. CSM makes use of the Coanda effect on axisymmetric geometries through the interaction of two jets: a primary jet and a control jet. The primary jet has larger volume flow rate but generally a smaller momentum flux than the control jet. The primary jet flows through the center of a rounded collar. The control jet is parallel to the primary and is adjacent to the convex collar. The Reynolds number range for the primary jet at the exit plane was between 20,000 and 80,000. The flow was in the incompressible Mach number range (Mach<0.3). The control jet attaches to the convex wall and vectors according to known Coanda effect principles, entraining and vectoring the primary jet, resulting in controllable r-{theta} directional spraying. Several annular control slots and collar radii were tested over a range of momentum flux ratios to determine the effects of these variables on the vectored jet angle and spreading. Two and Three-component Particle Image Velocimetry systems were used to determine the vectoring angle and the profile of the combined jet in each experiment. The experiments show that the control slot and expansion radius, along with the momentum ratios of the two jets predominantly affected the vectoring angle and profile of the combined jets. (orig.)

  6. Axisymmetric Coanda-assisted vectoring

    Science.gov (United States)

    Allen, Dustin; Smith, Barton L.

    2009-01-01

    An experimental demonstration of a jet vectoring technique used in our novel spray method called Coanda-assisted Spray Manipulation (CSM) is presented. CSM makes use of the Coanda effect on axisymmetric geometries through the interaction of two jets: a primary jet and a control jet. The primary jet has larger volume flow rate but generally a smaller momentum flux than the control jet. The primary jet flows through the center of a rounded collar. The control jet is parallel to the primary and is adjacent to the convex collar. The Reynolds number range for the primary jet at the exit plane was between 20,000 and 80,000. The flow was in the incompressible Mach number range (Mach Coanda effect principles, entraining and vectoring the primary jet, resulting in controllable r - θ directional spraying. Several annular control slots and collar radii were tested over a range of momentum flux ratios to determine the effects of these variables on the vectored jet angle and spreading. Two and Three-component Particle Image Velocimetry systems were used to determine the vectoring angle and the profile of the combined jet in each experiment. The experiments show that the control slot and expansion radius, along with the momentum ratios of the two jets predominantly affected the vectoring angle and profile of the combined jets.

  7. Standard mirror fusion reactor design study

    International Nuclear Information System (INIS)

    This report covers the work of the Magnetic Fusion Energy Division's reactor study group during FY 1976 on the standard mirror reactor. The ''standard'' mirror reactor is characterized as a steady state, neutral beam sustained, D-T fusioning plasma confined by a Yin-Yang magnetic mirror field. The physics parameters are obtained from the same physics model that explains the 2XIIB experiment. The model assumes that the drift cyclotron loss cone mode occurs on the boundary of the plasma, and that it is stabilized by warm plasma with negligible energy investment. The result of the study was a workable mirror fusion power plant, steady-state blanket removal made relatively simple by open-ended geometry, and no impurity problem due to the positive plasma potential. The Q (fusion power/injected beam power) turns out to be only 1.1 because of loss out the ends from Coulomb collisions, i.e., classical losses. This low Q resulted in 77% of the gross electrical power being used to power the injectors, thereby causing the net power cost to be high. The low Q stimulated an intensive search for Q-enhancement concepts, resulting in the LLL reactor design effort turning to the field reversal mirror and the tandem mirror, each having Q of order 5

  8. Experimental progress in magnetic-mirror fusion research

    Science.gov (United States)

    Simonen, T. C.

    1981-08-01

    This paper discusses experimental progress in the control, confinement, and understanding of magnetic-mirror confined plasmas. A summary is given of the data base established in previous experiments on which magnetic-mirror principles are based. It includes a detailed description of present tandem and field-reversed mirror experimental results. The discussion also includes the concepts and parameters of experiments now under construction; it is shown how these experiments can both test new thermal-barrier concepts and bridge the gap between existing facilities and eventual power producers. Consideration is given to small-scale physics-oriented experiments, aimed at testing new ideas and refining the knowledge of mirror confinement. The paper concludes with an extensive bibliography of reports from the field of magnetic-mirror fusion.

  9. Structural design considerations in the Mirror Fusion Test Facility (MFTF-B) vacuum vessel

    Energy Technology Data Exchange (ETDEWEB)

    Vepa, K.; Sterbentz, W.H.

    1981-02-10

    In view of favorable results from the Tandem Mirror Experiment (TMX) also at LLNL, the MFTF project is now being rescoped into a large tandem mirror configuration (MFTF-B), which is the mainline approach to a mirror fusion reactor. This paper concerns itself with the structural aspects of the design of the vessel. The vessel and its intended functions are described. The major structural design issues, especially those influenced by the analysis, are described. The objectives of the finite element analysis and their realization are discussed at length.

  10. Multiple mirror plasma confinement

    International Nuclear Information System (INIS)

    Multiple mirror plasma confinement concept is considered. A theory of plasma diffusion through a corrugated magnetic field is developed. It is shown, that multiple mirror devices hold considerable promise for confining fusion plasmas. 75 refs.; 8 figs.; 4 tabs

  11. Light, Color, and Mirrors.

    Science.gov (United States)

    Tiburzi, Brian; Tamborino, Laurie; Parker, Gordon A.

    2000-01-01

    Describes an exercise in which students can use flashlights, mirrors, and colored paper to discover scientific principles regarding optics. Addresses the concepts of angles of incidence and reflection, colored vs. white light, and mirror images. (WRM)

  12. Boundary element method for internal axisymmetric flow

    Directory of Open Access Journals (Sweden)

    Gokhman Alexander

    1999-01-01

    Full Text Available We present an accurate fast method for the computation of potential internal axisymmetric flow based on the boundary element technique. We prove that the computed velocity field asymptotically satisfies reasonable boundary conditions at infinity for various types of inlet/exit. Computation of internal axisymmetric potential flow is an essential ingredient in the three-dimensional problem of computation of velocity fields in turbomachines. We include the results of a practical application of the method to the computation of flow in turbomachines of Kaplan and Francis types.

  13. Structure of stationary and axisymmetric metrics

    International Nuclear Information System (INIS)

    We study the structure of stationary and axisymmetric metrics solving the vacuum Einstein equations of general relativity in four and higher dimensions, building on recent work in Phys. Rev. D 70, 124002 (2004). We write the Einstein equations in a new form that naturally identifies the sources for such metrics. The sources live in a one-dimensional subspace and the entire metric is uniquely determined by them. We study in detail the structure of stationary and axisymmetric metrics in four dimensions, and consider as an example the sources of the Kerr black hole

  14. The TESS [Tandem Experiment Simulation Studies] computer code user's manual

    International Nuclear Information System (INIS)

    TESS (Tandem Experiment Simulation Studies) is a one-dimensional, bounded particle-in-cell (PIC) simulation code designed to investigate the confinement and transport of plasma in a magnetic mirror device, including tandem mirror configurations. Mirror plasmas may be modeled in a system which includes an applied magnetic field and/or a self-consistent or applied electrostatic potential. The PIC code TESS is similar to the PIC code DIPSI (Direct Implicit Plasma Surface Interactions) which is designed to study plasma transport to and interaction with a solid surface. The codes TESS and DIPSI are direct descendants of the PIC code ES1 that was created by A. B. Langdon. This document provides the user with a brief description of the methods used in the code and a tutorial on the use of the code. 10 refs., 2 tabs

  15. Mirrors as power filters

    International Nuclear Information System (INIS)

    Multilayer mirrors offer advantages in power filtering compared to total reflection mirrors in both wiggler and undulator beams at third generation synchrotron radiation sources currently under construction. These advantages come at the expense of increased absorbed power in the mirror itself, and of added complexity of beamline optical design. This paper discusses these aspects

  16. Recent Progress in Mirror Studies in Novosibirsk

    International Nuclear Information System (INIS)

    At present, in the Budker Institute of Nuclear Physics there is in operation the most complete set of modern mirror machines based on different principles of plasma confinement. This set includes the multi-mirror system GOL-3 for confinement of dense plasma heated by relativistic electron beam, the gas dynamic trap (GDT) for confinement of collisional plasma and anisotropic fast ions, and the ambipolar trap AMBAL-M.Mirrors have a number of advantages in comparison with the closed magnetic systems like tokamak, stellarator, etc. The most important are the following. The effects of disruptions are not appeared in mirrors. There are no divertor problems in them. Plasma pressure in a mirror device can be comparable with magnetic field pressure. As to the multi-mirror system, in this case, the β value can be even significantly higher than unity (the so called >). At last, mirrors are convenient for direct conversion of energy of charged particles leaving out the ends. This circumstance can turn out to be especially important in future > schemes of fusion reactors.In principle, mirrors are very attractive from the engineering point of view, if the plasma confined in axisymmetric magnetic systems would be MHD stable. At present, the problem of MHD stability has already been solved for all axisymmetric traps designed in Novosibirsk. At least, the value β [approximately or equal to] 0.4 was obtained in these traps without any indications of macroscopic instability development.Some important results were obtained recently in the GOL-3 experiments. A specific mechanism of reduction of longitudinal electron thermal conductivity was detected. Recently, the magnetic system of the GOL-3 device was reconstructed into multi-mirror configuration. In this configuration, a new mechanism of fast ion heating was observed. As a result, the ion temperature was increased from a few eV up to 1 keV and the confinement time significantly increased (up to 1ms). These results were obtained

  17. Water Cooled Mirror Design

    Energy Technology Data Exchange (ETDEWEB)

    Dale, Gregory E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Holloway, Michael Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pulliam, Elias Noel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-03-30

    This design is intended to replace the current mirror setup being used for the NorthStar Moly 99 project in order to monitor the target coupon. The existing setup has limited movement for camera alignment and is difficult to align properly. This proposed conceptual design for a water cooled mirror will allow for greater thermal transfer between the mirror and the water block. It will also improve positioning of the mirror by using flexible vacuum hosing and a ball head joint capable of a wide range of motion. Incorporating this design into the target monitoring system will provide more efficient cooling of the mirror which will improve the amount of diffraction caused by the heating of the mirror. The process of aligning the mirror for accurate position will be greatly improved by increasing the range of motion by offering six degrees of freedom.

  18. Upgrading of the tandem

    International Nuclear Information System (INIS)

    The program of the tandem-linac accelerator system is summarized under the following headings: operating experience for the tandem, operation of the superconducting linac, upgrading of the tandem (ion sources, vacuum systems, terminal box, stripping foils, beam bunching), installation of the booster, planned accelerator system improvements, experimental facilities development at the super conducting-linac booster (new beam line, layout and installation of the 00 beam line in the new experiment area, beam optics calculations, 65-in. scattering chamber, split-pole spectrograph, sum/multiplicity detector, nuclear target making and development), and university use of the tandem accelerator

  19. Test bed concentrator mirrors

    Science.gov (United States)

    Argoud, M. J.

    1980-05-01

    The test bed concentrator (TBC) was des point focusing distributed receiver (PFDR) systems. The reflective surface of the concentrator was fabricated using mirror facet designs and techniques. The facets are made by bonding mirrored glass to spherically-conducted substrates. Several aspects of earlier work were reevaluated for application to the TBC: optimum glass block size, material selection, environmental test, optical characteristics, and reliability. A detailed explanation of tooling, substrate preparation, testing techniques, and mirror assembly is presented.

  20. Mesmerising mirror neurons.

    Science.gov (United States)

    Heyes, Cecilia

    2010-06-01

    Mirror neurons have been hailed as the key to understanding social cognition. I argue that three currents of thought-relating to evolution, atomism and telepathy-have magnified the perceived importance of mirror neurons. When they are understood to be a product of associative learning, rather than an adaptation for social cognition, mirror neurons are no longer mesmerising, but they continue to raise important questions about both the psychology of science and the neural bases of social cognition. PMID:20167276

  1. Manufacturing of Lightweight Mirror

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Fabrication of the lightweight mirror is one of the key techniques for many large optical systems. CAD,CAM and CNC technologies are adopted in designing and manufacturing such mirrors in CIOMP. Better working efficiency and higher lightweight grade have been achieved. The results show that mirrors up to 70% weight reduction and 0.02λ(rms.) surface accuracy or better can be obtained.

  2. Equilibrium and stability of the Tara tandem mirror experiment

    International Nuclear Information System (INIS)

    The MHD equilibrium and stability of the Tara machine is analyzed. MHD equilibrium theory is shown to predict small distortions away from circular pressure surfaces in the Tara experiment due to parallel currents generated in the nonaxisymmetric anchors. Central cell fluctuations are dominated by radially rigid, m = 1 flute modes in which the entire column oscillates about the machine axis. These modes can be stabilized by outboard quadrupole anchors, but are also sensitive to gas input and central cell ion cyclotron heating (ICH) power levels. During the strong endloss reduction realized in plugging experiments, the source for the anchor plasma is cut off with a consequent decline in ion beta leading to a reappearance of central cell flute modes. A magnetic divertor installed at the central cell mid-plane in order to ameliorate this difficulty has significantly enlarged the stable operating parameter regime. Axially localized instabilities are clearly observed in the plug cells during the application of plug ICH and are conjectured to exist during the application of axicell ECH. 23 refs., 8 figs

  3. Modeling of ICRH experiments in the Tara tandem mirror

    International Nuclear Information System (INIS)

    The production and heating of the central cell plasma in Tara are provided by a slot antenna located on the midplane bump of the axial magnetic field profile. Slow ion cyclotron waves excited by the slot propagate down a magnetic beach to ion cyclotron resonance layers located on either side of the bump where the rf power is strongly damped by the ions. Two different theoretical models are being used to study the efficiency of coupling to slow waves in this configuration. Wave propagation models which are based on the infinite plasma dispersion relation for a cold plasma indicate that radially propagating left hand polarized slow waves are converted to right hand polarized fast waves at the Alfven resonance layer due to the radial density gradient. If this were to occur we would expect a lower coupling efficiency to the ions in the plasma core. On the other hand, a nonlocal kinetic model of rf wave propagation in a nonuniform plasma slab indicates that a significant left hand component of the electric field extends beyond the Alfven resonance layer. Preliminary experimental measurements of the radial inductive field profile agree qualitatively with the predictions of the cold plasma model, however, there is insufficient data at this time to establish that a density limit for slow wave accessibility to the plasma core exists

  4. Impurity ion diagnostics in the GAMMA 10 tandem mirror

    International Nuclear Information System (INIS)

    We constructed some spectroscopic measurement systems that cover the wavelength range from soft X-ray (SX) to visible lights. We have observed the absolute impunity line intensities, Doppler line broadenings, Doppler shifts by ultraviolet and visible spectrograph and time dependent radial profiles of the impurity lines by the vacuum ultraviolet (VUV) and the SX spectrographs. We determined the radiation loss in the wavelength range from visible to VUV and carbon ion density. These spectroscopic systems could be powerful tools to diagnose the GAMMA 10 plasma in a long pulse operation. (author)

  5. Impurity ion diagnostics in the GAMMA 10 tandem mirror

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, Masayuki; Okamoto, Yuuji; Kawamori, Eiichiro [Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki (Japan)] (and others)

    2000-07-01

    We constructed some spectroscopic measurement systems that cover the wavelength range from soft X-ray (SX) to visible lights. We have observed the absolute impunity line intensities, Doppler line broadenings, Doppler shifts by ultraviolet and visible spectrograph and time dependent radial profiles of the impurity lines by the vacuum ultraviolet (VUV) and the SX spectrographs. We determined the radiation loss in the wavelength range from visible to VUV and carbon ion density. These spectroscopic systems could be powerful tools to diagnose the GAMMA 10 plasma in a long pulse operation. (author)

  6. Global stability analysis of axisymmetric boundary layers

    CERN Document Server

    Vinod, N

    2016-01-01

    This paper presents the linear global stability analysis of the incompressible axisymmetric boundary layer on a circular cylinder. The base flow is parallel to the axis of the cylinder at inlet. The pressure gradient is zero in the streamwise direction. The base flow velocity profile is fully non-parallel and non-similar in nature. The boundary layer grows continuously in the spatial directions. Linearized Navier-Stokes(LNS) equations are derived for the disturbance flow quantities in the cylindrical polar coordinates. The LNS equations along with homogeneous boundary conditions forms a generalized eigenvalues problem. Since the base flow is axisymmetric, the disturbances are periodic in azimuthal direction. Chebyshev spectral collocation method and Arnoldi's iterative algorithm is used for the solution of the general eigenvalues problem. The global temporal modes are computed for the range of Reynolds numbers and different azimuthal wave numbers. The largest imaginary part of the computed eigenmodes are nega...

  7. The evolution of swirling axisymmetric vortex rings

    Science.gov (United States)

    Gargan-Shingles, C.; Rudman, M.; Ryan, K.

    2015-08-01

    Swirling vortex rings form in any turbulent flow where a swirling component is present, such as in combustion chambers or the downwash of helicopter blades. Instabilities on initially non-swirling vortex rings result in a localized swirl velocity being generated within the core. The presence of a swirl component of velocity in a vortex ring modifies the relaxation and evolution of numerical Gaussian cores in a manner that is currently unknown. The evolution of Gaussian axisymmetric vortex rings of size 0.2 complete settling of the strain rate within the core does not occur until all sheddings have ceased. Increasing the swirl magnitude past that considered in this paper is expected to result in the original ring losing its structure before the instability can occur. The evolution is found to be qualitatively similar to that of a piston generated axisymmetric vortex ring with swirl, with both cases eventually reaching a similar quasi-steady state.

  8. Orbital effect in the stationary axisymmetric field

    International Nuclear Information System (INIS)

    This paper uses an elegant mathematical method to calculate the orbital effects in the axisymmetric field created by the spinning mass with electric charge and a large number of magnetic monopoles. In comparison with that in the Reissner–Nordström (R–N) field, the correction terms caused by the spinning mass decrease the advanced effect as the revolution direction of the test particle coincides with that of the Kerr field, however, the correction terms caused by the spinning charged mass increase the advance effect as the revolution direction of the test particle coincides with that of the Kerr–Newman–Kasnya (KNK) field. Generalizing the effect in the axisymmetric field, it obtains interesting results by discussing the parameters of the celestial body, these parameters provide a feasible experimental verification of the general relativity. (general)

  9. An axisymmetric steady state vortex ring model

    CERN Document Server

    Wang, Ruo-Qian

    2016-01-01

    Based on the solution of Atanasiu et al. (2004), a theoretical model for axisymmetric vortex flows is derived in the present study by solving the vorticity transport equation for an inviscid, incompressible fluid in cylindrical coordinates. The model can describe a variety of axisymmetric flows with particular boundary conditions at a moderately high Reynolds number. This paper shows one example: a high Reynolds number laminar vortex ring. The model can represent a family of vortex rings by specifying the modulus function using a Rayleigh distribution function. The characteristics of this vortex ring family are illustrated by numerical methods. For verification, the model results compare well with the recent direct numerical simulations (DNS) in terms of the vorticity distribution and streamline patterns, cross-sectional areas of the vortex core and bubble, and radial vorticity distribution through the vortex center. Most importantly, the asymmetry and elliptical outline of the vorticity profile are well capt...

  10. Orbital effect in the stationary axisymmetric field

    Institute of Scientific and Technical Information of China (English)

    Gong Tian-Xi; Wang Yong-Jiu

    2008-01-01

    This paper uses an elegant mathematical method to calculate the orbital effects in the axisymmetric field created by the spinning mass with electric charge and a large number of magnetic monopoles. In comparison with that in the Reissner-Nordstrom (R-N) field, the correction terms caused by the spinning mass decrease the advanced effect as the revolution direction of the test particle coincides with that of the Kerr field, however, the correction terms caused by the spinning charged mass increase the advance effect as the revolution direction of the test particle coincides with that of the Kerr-Newman-Kasnya (KNK) field. Generalizing the effect in the axisymmetric field, it obtains interesting results by discussing the parameters of the celestial body, these parameters provide a feasible experimental verification of the general relativity.

  11. Collapse of Non-Axisymmetric Cavities

    OpenAIRE

    Enriquez, Oscar R.; Peters, Ivo R.; Gekle, Stephan; Schmidt, Laura; Versluis, Michel; van der Meer, Devaraj; Lohse, Detlef

    2009-01-01

    A round disk with a harmonic disturbance impacts on a water surface and creates a non-axisymmetric cavity which collapses under the influence of hydrostatic pressure. We use disks deformed with mode m=2 to m=6. For all mode numbers we find clear evidence for a phase inversion of the cavity wall during the collapse. We present a fluid dynamics video showing high speed imaging of different modes, pointing out the characteristic features during collapse.

  12. Numerical description of cavitation on axisymmetric bodies

    Energy Technology Data Exchange (ETDEWEB)

    Hickox, C.E.; Hailey, C.E.; Wolfe, W.P.; Watts, H.A.; Gross, R.J.; Ingber, M.S.

    1988-01-01

    This paper reports on ongoing studies which are directed toward the development of predictive techniques for the modeling of steady cavitation on axisymmetric bodies. The primary goal of the modeling effort is the prediction of cavity shape and pressure distribution from which forces and moments can be calculated. Here we present an overview of the modeling techniques developed and compare predictions with experimental data obtained from water tunnel tests for both limited and supercavitation. 14 refs., 4 figs.

  13. Axisymmetric stationary solutions as harmonic maps

    CERN Document Server

    Matos, T; Tonatiuh Matos; Jerzy Plebanski

    1994-01-01

    We present a method for generating exact solutions of Einstein equations in vacuum using harmonic maps, when the spacetime possesses two commutating Killing vectors. This method consists in writing the axisymmetric stationry Einstein equations in vacuum as a harmonic map which belongs to the group SL(2,R), and decomposing it in its harmonic "submaps". This method provides a natural classification of the solutions in classes (Weil's class, Lewis' class etc).

  14. Analysis of Axisymmetric Crushing of Frusta

    OpenAIRE

    M.M.A. Khan; H. Abbas; N K Gupta

    2003-01-01

    The paper presents a curved-fold model with variable straight length for the axisymmetric crushing of thin frusta. The folding considered in the model is partly inside and partly outside. The variation of circumferential strain during the formation of a fold has been taken into account. The size of the fold and mean, as well as variation of crushing load, has been computed mathematically. The study is purely analytical and does not involve any empirical constant; and hence, can be used...

  15. AXISYMMETRIC ELASTICITY PROBLEM OF CUBIC QUASICRYSTAL

    Institute of Scientific and Technical Information of China (English)

    ZHOU WANG-MIN; FAN TIAN-YOU

    2000-01-01

    A method for analyzing the elasticity problem of cubic quasicrystal is developed. The axisymmetric elasticity problem of cubic quasicrystal is reduced to a single higher-order partial differential equation by introducing a displacement function. As an example, the solutions of elastic field of cubic quasicrystal with a penny-shaped crack are obtained,and the stress intensity factor and strain energy release rate are determined.

  16. Axisymmetric long liquid bridges stability and resonances

    OpenAIRE

    Meseguer Ruiz, José; Sanz Andres, Angel Pedro; Perales Perales, José Manuel

    1990-01-01

    In this paper mathematical expressions for minimum-volume stability limits and resonance frequencies of axisymmetric long liquid bridges are presented. These expressions are valid for a wide range of liquid bridge configurations, accounting for ef-fects like unequal disks and axial microgravity in the case of minimum-volume stability limits,and unequal disks, axial microgravity,non-zero viscosity and liquid bridge volume different from the cylindrical one in the case of resonance frequenc...

  17. Axisymmetric oscillations of magnetic neutron stars

    CERN Document Server

    Lee, U

    2006-01-01

    We calculate axisymmetric oscillations of rotating neutron stars composed of the surface fluid ocean, solid crust, and fluid core, taking account of a dipole magnetic field as strong as $B_S\\sim 10^{15}$G at the surface. The adiabatic oscillation equations for the solid crust threaded by a dipole magnetic field are derived in Newtonian dynamics, on the assumption that the axis of rotation is aligned with the magnetic axis so that perturbations on the equilibrium can be represented by series expansions in terms of spherical harmonic functions $Y_l^m(\\theta,\\phi)$ with different degrees $l$ for a given azimuthal wave number $m$ around the the magnetic axis. Although the three component models can support a rich variety of oscillation modes, axisymmetric ($m=0$) toroidal $_{l}t_n$ and spheroidal $_ls_n$ shear waves propagating in the solid crust are our main concerns, where $l$ and $n$ denote the harmonic degree and the radial order of the modes, respectively. In the absence of rotation, axisymmetric spheroidal ...

  18. Bronze rainbow hologram mirrors

    Science.gov (United States)

    Dawson, P.

    2006-02-01

    This project draws on holographic embossing techniques, ancient artistic conventions of bronze mirror design and modelling and casting processes to accomplish portraiture of reflection. Laser scanning, 3D computer graphics and holographic imaging are employed to enable a permanent 3D static holographic image to appear integrated with the real-time moving reflection of a viewer's face in a polished bronze disc. The disc and the figure which holds it (caryatid) are cast in bronze from a lost wax model, a technique which has been used for millennia to make personal mirrors. The Caryatid form of bronze mirror which went through many permutations in ancient Egyptian, Greece and Rome shows a plethora of expressive figure poses ranging from sleek nudes to highly embellished multifigure arrangements. The prototype of this series was made for Australian choreographer Graeme Murphy, Artistic Director of the Sydney Dance Company. Each subsequent mirror will be unique in figure and holographic imagery as arranged between artist and subject. Conceptually this project references both the modern experience of viewing mirrors retrieved from ancient tombs, which due to deterioration of the surface no longer reflect, and the functioning of Chinese Magic mirrors, which have the ability to project a predetermined image. Inspired by the metaphorical potential of these mirrors, which do not reflect the immediate reality of the viewer, this bronze hologram mirror series enables each viewer to reflect upon himself or herself observing simultaneously the holographic image and their own partially obliterated reflection.

  19. Diagnostics for mirror machines

    International Nuclear Information System (INIS)

    This paper is subdivided into three chapters to match three corresponding lectures. The goals of the first chapter are to define the neutral-beam-heated, quasi-d.c. mirror confinement systems under discussion here and to give a general example of mirror diagnostics by listing and very briefly discussing the diagnostics used on the 2XIIB experiment at the Lawrence Livermore Laboratory. The second chapter develops mirror machine diagnostics in more detail, and adds background for a few selected diagnostics of particular importance to mirror machine studies. The third chapter discusses the special diagnostic needs of future mirror machines, with emphasis on diagnostics involving the higher-power neutral beams used with them

  20. Nonlinear mirror instability

    CERN Document Server

    Rincon, F; Cowley, S C

    2014-01-01

    Slow dynamical changes in magnetic-field strength and invariance of the particles' magnetic moments generate ubiquitous pressure anisotropies in weakly collisional, magnetized astrophysical plasmas. This renders them unstable to fast, small-scale mirror and firehose instabilities, which are capable of exerting feedback on the macroscale dynamics of the system. By way of a new asymptotic theory of the early nonlinear evolution of the mirror instability in a plasma subject to slow shearing or compression, we show that the instability does not saturate quasilinearly at a steady, low-amplitude level. Instead, the trapping of particles in small-scale mirrors leads to nonlinear secular growth of magnetic perturbations, $\\delta B/B \\propto t^{2/3}$. Our theory explains recent collisionless simulation results, provides a prediction of the mirror evolution in weakly collisional plasmas and establishes a foundation for a theory of nonlinear mirror dynamics with trapping, valid up to $\\delta B/B =O(1)$.

  1. Mirror boxes and mirror mounts for photophysics beamline

    International Nuclear Information System (INIS)

    Photophysics beamline makes use of one metre Seya-Namioka monochromator and two toroidal mirrors in its fore optics. The first toroidal mirror (pre mirror) focuses light originating from the tangent point of the storage ring onto the entrance slit of the monochromator and second toroidal mirror (post mirror) collects light from the exit slit of the monochromator and focuses light onto the sample placed at a distance of about one metre away from the 2nd mirror. To steer light through monochromator and to focus it on the sample of 1mm x 1mm size require precision rotational and translational motion of the mirrors and this has been achieved with the help of precision mirror mounts. Since Indus-1 operates at pressures less than 10-9 m.bar, the mirror mounts should be manipulated under similar ultra high vacuum conditions. Considering these requirements, two mirror boxes and two mirror mounts have been designed and fabricated. The coarse movements to the mirrors are imparted from outside the mirror chamber with the help of x-y tables and precision movements to the mirrors are achieved with the help of mirror mounts. The UHV compatibility and performance of the mirror mounts connected to mirror boxes under ultra high vacuum condition is evaluated. The details of the design, fabrication and performance evaluation are discussed in this report. 5 refs., 9 figs., 1 tab

  2. Mirror Advanced Reactor Study engineering overview

    International Nuclear Information System (INIS)

    The Mirror Advanced Reactor Study (MARS) was the first comprehensive conceptual design of a commercial tandem mirror reactor with thermal barriers. The design exploited the inherent attractive features of a tandem mirror: steady state operation, linear central cell, simple high performance blankets, low first wall heat fluxes, natural impurity diversion by the halo plasma, no driven plasma currents or associated disruptions, and direct conversion of the charged particle power lost out the ends. The study introduced new design concepts in high field magnets, neutral beams, ECRH systems, drift pumping, direct conversion, lithium-lead blankets and plant safety. The MARS design would produce 1200 MWsub(e) net and more than 1500 MWsub(e) gross from only 2600 MW of fusion power. This high efficiency is achieved through a combination of blanket design and direct conversion. Special emphasis was placed on fusion's potential for inherent safety, lower activation and simpler disposal of radioactive waste as compared with fission. The blanket has a very low tritium inventory, cannot melt in loss-of-coolant and/or loss-of-flow accidents and can be disposed of as low level waste subject to near-surface burial. MARS would produce busbar electricity at about 7 cents per kilowatthour (constant 1983 dollars). This value is near the upper end of the cost range for new generation capability being installed in the late 1980's. Significant cost reductions can be gained by further improvements in the engineering designs combined with a simplified end cell. The largest cost reductions from engineering can be attained through redesigned magnets, heat transport system and electrical system. The combination of engineering and physics improvements are projected to lower the cost of electricity by about 40% without sacrificing the environmental, safety and maintainability attributes of MARS. This work is now being pursued in the MINIMARS study. (orig.)

  3. Preferential axisymmetric field growth in kinematic geodynamo models

    Science.gov (United States)

    Livermore, Philip W.; Jackson, Andrew

    2004-11-01

    Earth's magnetic field, generated by fluid motion and inductive processes in Earth's core, has a predominantly axisymmetric dipolar component. Yet indefinite self-excitation of purely axisymmetric fields through any dynamo mechanism is specifically disallowed, begging the question of why the geodynamo sustains this dominant axisymmetric component. By considering a number of different fluid flow models modified from existing studies, we show that axisymmetric fields are consistently the most easily regenerated magnetic fields on short timescales, despite the fact that on long timescales they must die away. We argue that this transient field generation may play an important role in generating Earth's magnetic field, especially in the recovery after reversals.

  4. Low Cost Method of Manufacturing Cooled Axisymmetric Scramjets Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Scramjet engine developers are working on advanced axisymmetric engine concepts that may not be feasible due to limitations of currently available manufacturing...

  5. Axisymmetric instability in a thinning electrified jet

    Science.gov (United States)

    Dharmansh; Chokshi, Paresh

    2016-04-01

    The axisymmetric stability of an electrified jet is analyzed under electrospinning conditions using the linear stability theory. The fluid is considered Newtonian with a finite electrical conductivity, modeled as a leaky dielectric medium. While the previous studies impose axisymmetric disturbances on a cylindrical jet of uniform radius, referred to as the base state, in the present study the actual thinning jet profile, obtained as the steady-state solution of the one-dimensional slender filament model, is treated as the base state. The analysis takes into account the role of variation in the jet variables like radius, velocity, electric field, and surface charge density along the thinning jet in the stability behavior. The eigenspectrum of the axisymmetric disturbance growth rate is constructed from the linearized disturbance equations discretized using the Chebyshev collocation method. The most unstable growth rate for the thinning jet is significantly different from that for the uniform radius jet. For the same electrospinning conditions, while the uniform radius jet is predicted to be highly unstable, the thinning jet profile is found to be unstable but with a relatively very low growth rate. The stabilizing role of the thinning jet is attributed to the variation in the surface charge density as well as the extensional deformation rate in the fluid ignored in the uniform radius jet analysis. The dominant mode for the thinning jet is an oscillatory conducting mode driven by the field-charge coupling. The disturbance energy balance finds the electric force to be the dominant force responsible for the disturbance growth, potentially leading to bead formation along the fiber. The role of various material and process parameters in the stability behavior is also investigated.

  6. Tandem mobile robot system

    Science.gov (United States)

    Buttz, James H.; Shirey, David L.; Hayward, David R.

    2003-01-01

    A robotic vehicle system for terrain navigation mobility provides a way to climb stairs, cross crevices, and navigate across difficult terrain by coupling two or more mobile robots with a coupling device and controlling the robots cooperatively in tandem.

  7. The Mirror Oscilloscpoe

    OpenAIRE

    Goudriaan, B.

    2003-01-01

    This project is about designing and realizing an oscilloscope based on a laser beam reflected by two mirrors. The ¿Mirror Oscilloscope¿ uses two voice-coils actuators with mounted mirrors to reflect laser light, such that an image of a harmonic signal is projected on a projection screen. For tracking of the input signal an encoder is chosen as a position feedback sensor. Using a 20sim model, 20sim¿s code-generation tool and the AD VisualDSP++ environment, an uploadable program is made, interp...

  8. Topological fluid mechanics of Axisymmetric Flow

    DEFF Research Database (Denmark)

    Brøns, Morten

    Topological fluid mechanics in the sense of the present paper is the study and classification of flow patterns close to a critical point. Here we discuss the topology of steady viscous incompressible axisymmetric flows in the vicinity of the axis. Following previous studies the velocity field v is...... authors knowledge has not been used systematically to high orders in topological fluid mechanics. We compare the general results with experimental and computational results on the Vogel-Ronneberg flow. We show that the topology changes observed when recirculating bubbles on the vortex axis are created and...

  9. Reversed straining in axisymmetric compression test

    DEFF Research Database (Denmark)

    Arentoft, Mogens; Wanheim, Tarras; Lindegren, Maria;

    2005-01-01

    A large group of the cold forging processes is carried out in a thick – walled container with the deformation force transmitted through a punch moving axially in the container. The work piece, being entrapped between punch and container will expand and exert a radial pressure resulting in an expa...... simulate these conditions a reversed axisymmetrical material tester is designed and constructed. Three different materials were tested, aluminum alloy AA6082, technically pure copper (99.5%) and cold forging steel Ma8, at different temperatures found during cold forging....

  10. Travelling waves in axisymmetric pipe flows

    International Nuclear Information System (INIS)

    The weakly nonlinear dynamics of axisymmetric Poiseuille pipe flows is investigated. It is shown that small perturbations of the laminar flow with amplitude ε ∼ O(Re−2.5) obey a coupled system of nonlinear Korteweg–de Vries-type equations. To leading order, these support inviscid soliton-type solutions and periodic waves in the form of toroidal vortex tubes that, due to viscous effects, slowly decay in time on a longer time scale t ∼ O(ε−2.5). (paper)

  11. Comment on "Conformally flat stationary axisymmetric metrics"

    CERN Document Server

    Barnes, A; Senovilla, José MM

    2003-01-01

    Garcia and Campuzano claim to have found a previously overlooked family of stationary and axisymmetric conformally flat spacetimes, contradicting an old theorem of Collinson. In both these papers it is tacitly assumed that the isometry group is orthogonally transitive. Under the same assumption, we point out here that Collinson's result still holds if one demands the existence of an axis of symmetry on which the axial Killing vector vanishes. On the other hand if the assumption of orthogonal transitivity is dropped, a wider class of metrics is allowed and it is possible to find explicit counterexamples to Collinson's result.

  12. Active array design for FAME: Freeform Active Mirror Experiment

    Science.gov (United States)

    Jaskó, Attila; Aitink-Kroes, Gabby; Agócs, Tibor; Venema, Lars; Hugot, Emmanuel; Schnetler, Hermine; Bányai, Evelin

    2014-07-01

    In this paper a status report is given on the development of the FAME (Freeform Active Mirror Experiment) active array. Further information regarding this project can be found in the paper by Venema et al. (this conference). Freeform optics provide the opportunity to drastically reduce the complexity of the future optical instruments. In order to produce these non-axisymmetric freeform optics with up to 1 mm deviation from the best fit sphere, it is necessary to come up with new design and manufacturing methods. The way we would like to create novel freeform optics is by fine tuning a preformed high surface-quality thin mirror using an array which is actively controlled by actuators. In the following we introduce the tools deployed to create and assess the individual designs. The result is an active array having optimal number and lay-out of actuators.

  13. Mirror reactor surface study

    International Nuclear Information System (INIS)

    A general survey is presented of surface-related phenomena associated with the following mirror reactor elements: plasma first wall, ion sources, neutral beams, director converters, vacuum systems, and plasma diagnostics. A discussion of surface phenomena in possible abnormal reactor operation is included. Several studies which appear to merit immediate attention and which are essential to the development of mirror reactors are abstracted from the list of recommended areas for surface work. The appendix contains a discussion of the fundamentals of particle/surface interactions. The interactions surveyed are backscattering, thermal desorption, sputtering, diffusion, particle ranges in solids, and surface spectroscopic methods. A bibliography lists references in a number of categories pertinent to mirror reactors. Several complete published and unpublished reports on surface aspects of current mirror plasma experiments and reactor developments are also included

  14. Manufacturing parabolic mirrors

    CERN Multimedia

    1975-01-01

    The photo shows the construction of a vertical centrifuge mounted on an air cushion, with a precision of 1/10000 during rotation, used for the manufacture of very high=precision parabolic mirrors. (See Annual Report 1974.)

  15. The obsidian mirror The obsidian mirror

    Directory of Open Access Journals (Sweden)

    Maria do Socorro Reis Amorin

    2008-04-01

    Full Text Available The author James Norman is an American who has always lived in Mexico during the summer. He seems to love Mexican - Indian traditions and he is well acquainted with the pre-historic culture as it is shown in his book: "The Obsidian Mirror". "The Obsidian Mirror" is a mysterious story about an archeologist: Quigley that lives in a small village in Mexico-San Marcos. He is searching for antiques that belong to some tribes of pre-historic Indians in order to find out their mysteries. Quigley becomes so engaged in his work that his mind has reached a stage that is impossible to separate between Quigley the archeologist, and Quigley as an ancient Indian. The culture, the myth, the sensation of Omen - characteristics of the Indians are within himself. As a result, Quigley acts sometimes as a real Indian. The author James Norman is an American who has always lived in Mexico during the summer. He seems to love Mexican - Indian traditions and he is well acquainted with the pre-historic culture as it is shown in his book: "The Obsidian Mirror". "The Obsidian Mirror" is a mysterious story about an archeologist: Quigley that lives in a small village in Mexico-San Marcos. He is searching for antiques that belong to some tribes of pre-historic Indians in order to find out their mysteries. Quigley becomes so engaged in his work that his mind has reached a stage that is impossible to separate between Quigley the archeologist, and Quigley as an ancient Indian. The culture, the myth, the sensation of Omen - characteristics of the Indians are within himself. As a result, Quigley acts sometimes as a real Indian.

  16. Mirror contamination in space I: mirror modelling

    Science.gov (United States)

    Krijger, J. M.; Snel, R.; van Harten, G.; Rietjens, J. H. H.; Aben, I.

    2014-10-01

    We present a comprehensive model that can be employed to describe and correct for degradation of (scan) mirrors and diffusers in satellite instruments that suffer from changing optical Ultraviolet to visible (UV-VIS) properties during their operational lifetime. As trend studies become more important, so does the importance of understanding and correcting for this degradation. This is the case not only with respect to the transmission of the optical components, but also with respect to wavelength, polarisation, or scan-angle effects. Our hypothesis is that mirrors in flight suffer from the deposition of a thin absorbing layer of contaminant, which slowly builds up over time. We describe this with the Mueller matrix formalism and Fresnel equations for thin multi-layer contamination films. Special care is taken to avoid the confusion often present in earlier publications concerning the Mueller matrix calculus with out-of-plane reflections. The method can be applied to any UV-VIS satellite instrument. We illustrate and verify our approach to the optical behaviour of the multiple scan mirrors of SCIAMACHY (onboard ENVISAT).

  17. Modern magnetic mirror systems. Status and perspectives

    International Nuclear Information System (INIS)

    Full text: Principles of multi-mirror plasma confinement and gas-dynamic one were proposed in the Budker INP in early and late 70 s, correspondingly. The first experiments have demonstrated a correctness of these approaches. In the paper the status of the experiments on two modern magnetic mirror devices is discussed. At present, the multi-mirror system GOL-3 has 12 m long magnetic system which consists of 55 mirror cells. The magnetic field strength is 4.8 T in the mirrors and 3.2 T in middle planes of each cell. Dense (ne > 1021 m-3) plasma in the solenoid is heated by high current relativistic electron beam (E = 1 MeV, Ib = 30 kA, Τb = 8 x 10-6 s) and is confined in the multi-mirror system. Note a simplicity of this method of plasma confinement (axial symmetry of the magnetic configuration), practicability of high β (order of 1 or even more). The present day parameters are: Te ∼ Ti ∼ 2 keV. Such plasma is sustained during ΤE ∼ 1 ms and there are no physical limitations to increase them. But even with present day parameters a lot of experiments can be made on plasma-wall interaction (study of evaporation, erosion and ionization of wall materials, propagation of ions of these materials along magnetic field lines at long distances, disruption and ELM simulations, etc) using the streams (up to 50 MJ/m2) flowing out along the axis. The second system is Gas Dynamic Trap (GDT). It is an axisymmetric mirror system with very high mirror ratio (R ∼ 102). The distance between mirrors, L = 7 meters and magnetic field in them is 15 T. Recently it was demonstrated that the GDT concept based on use of 'warm' plasma and oblique injection of D-T neutral beams can lead to creation of a simplest plasma neutron source with high density 14 MeV neutron flux reaching up to 2 MW/m2 on the limited part (order of 1 m2) of the device. The principles of the GDT operation have been already demonstrated at moderate parameters of plasma and NB injection. In particular, stable

  18. Improved micromorph tandem cell performance through enhanced top cell currents

    Energy Technology Data Exchange (ETDEWEB)

    Platz, R.; Vaucher, N.P.; Fischer, D.; Meier, J.; Shah, A. [Univ. de Neuchatel (Switzerland). Inst. de Microtechnique

    1997-12-31

    Two approaches to increasing the current in the amorphous silicon top cell of an amorphous silicon/microcrystalline silicon (a-Si:H/{micro}c-Si:H) tandem cell are presented. The goal is to raise the stabilized efficiency of such cells. The deposition of the amorphous top cell at higher than standard substrate temperature is shown to reduce the optical gap of the i-layer and to increase the current which is generated with a given i-layer thickness. Furthermore, a selectively reflecting ZnO interface layer between the component cells is presented as a viable tool for enhancing the current generation in the top cell by selective reflection of light. The authors present a micromorph tandem cell containing the amorphous top cell deposited at high substrate temperature, and additionally the ZnO mirror layer. A top cell thickness of 150 nm is shown to be sufficient to provide a current density of 13mA/cm{sup 2} in the top cell. Finally, the influence of such thin top cells on the stabilized efficiency of the tandem cell is investigated by experiment and by means of semi-empirical modeling. Model and experiment confirm that such reduced-gap top cells, together with current enhancement due to the mirror layer, have a high potential for improving the stabilized efficiency of micromorph tandem cells.

  19. Axisymmetric fretting analysis in coated cylinder

    Indian Academy of Sciences (India)

    M Ramesh; Satish V Kailas; K R Y Simha

    2008-06-01

    Fretting is essentially a contact fatigue phenomenon, although bulk stresses and material properties contribute to final failure. The near surface state of stress developed under oscillatory contact between machine elements plays a major role in deciding the severity of fretting. It is possible to enhance tribological properties by coating the surface. There is rather scanty literature available on fretting analysis of coated components. Presence of such coatings has a large influence on the near surface state of stress. The effect of coatings on the severity of fretting is the focus of this paper. Results obtained for both hard and soft coatings are compared with the results obtained for the homogeneous case. The component geometry and loading are chosen to be cylindrical to enable 3D elastic axisymmetric fretting analysis. The results are compared with 2D models (strip and half-plane) to examine their utility and validity for understanding axisymmetric fretting. Contact pressure and frictional shear loading cases are solved separately and superposed appropriately depending on the coefficient of friction considered. Results for different values of coefficient of friction and elastic mismatch are illustrated through contour plots of stresses and strains. These results are expected to be helpful for identifying fretting failure zones and fracture mechanisms in coated components. Analytical results presented here could serve as useful benchmarks for calibrating numerical codes and experimental techniques.

  20. Classification of Stellar Orbits in Axisymmetric Galaxies

    Science.gov (United States)

    Li, Baile; Holley-Bockelmann, Kelly; Khan, Fazeel Mahmood

    2015-09-01

    It is known that two supermassive black holes (SMBHs) cannot merge in a spherical galaxy within a Hubble time; an emerging picture is that galaxy geometry, rotation, and large potential perturbations may usher the SMBH binary through the critical three-body scattering phase and ultimately drive the SMBH to coalesce. We explore the orbital content within an N-body model of a mildly flattened, non-rotating, SMBH-embedded elliptical galaxy. When used as the foundation for a study on the SMBH binary coalescence, the black holes bypassed the binary stalling often seen within spherical galaxies and merged on gigayear timescales. Using both frequency-mapping and angular momentum criteria, we identify a wealth of resonant orbits in the axisymmetric model, including saucers, that are absent from an otherwise identical spherical system and that can potentially interact with the binary. We quantified the set of orbits that could be scattered by the SMBH binary, and found that the axisymmetric model contained nearly six times the number of these potential loss cone orbits compared to our equivalent spherical model. In this flattened model, the mass of these orbits is more than three times that of the SMBH, which is consistent with what the SMBH binary needs to scatter to transition into the gravitational wave regime.

  1. Classification of Stellar Orbits in Axisymmetric Galaxies

    CERN Document Server

    Li, Baile; Khan, Fazeel

    2014-01-01

    It is known that two supermassive black holes (SMBHs) cannot merge in a spherical galaxy within a Hubble time; an emerging picture is that galaxy geometry, rotation, and large potential perturbations may usher the SMBH binary through the critical three-body scattering phase and ultimately drive the SMBH to coalesce. We explore the orbital content within an N-body model of a mildly- flattened, non-rotating, SMBH-embedded elliptical galaxy. When used as the foundation for a study on the SMBH binary coalescence, the black holes bypassed the binary stalling often seen within spherical galaxies and merged on Gyr timescales (Khan et al. 2013). Using both frequency-mapping and angular momentum criteria, we identify a wealth of resonant orbits in the axisymmetric model, including saucers, that are absent from an otherwise identical spherical system and that can potentially interact with the binary. We quantified the set of orbits that could be scattered by the SMBH binary, and found that the axisymmetric model contai...

  2. Mirror fusion--another path to fusion power

    International Nuclear Information System (INIS)

    The Lawrence Livermore National Laboratory (LNL) in California has the primary responsibility for developing the mirror approach to magnetic fusion--generally regarded as the second most important effort after the Tokamak. Current emphasis is on the main program goal--the tandem mirror reactor (TMR). At this point, the TMR has a strong theoretical physics base scoupled with moderate to very difficult technological problems (e.g., high-field superconducting magnets, continuous vacuum-pumping systems, and high-energy neutral beams). An alternate approach, the field-reversed mirror reactor, requires less demandding technology, but has physics that is less well understood. In addition, there are studies of fission/fusion hybrid reactors that produce both electricity and fissile fuels to supply today's light-water reactors. Other studies are aimed at producing portable fuels (hydrogen, hydrocarbons, etc.) using the thermal output of a TMR to drive a thermochemical cycle. 17 refs

  3. Control algorithm for the petal-shape segmented-mirror telescope with 18 mirrors

    Science.gov (United States)

    Shimono, Atsushi; Iwamuro, Fumihide; Kurita, Mikio; Moritani, Yuki; Kino, Masaru; Maihara, Toshinori; Izumiura, Hideyuki; Yoshida, Michitoshi

    2012-09-01

    A 3.8 m segmented telescope is planned to be built at the Okayama Astrophysical Observatory by the joint program among Kyoto university, Nagoya university, NAOJ, and Nano-Optonics Energy Inc. This is the world’s first optical-infrared telescope whose primary mirror is composed of “petal-shaped” segment mirrors. To investigate the best layout of the displacement sensors as well as to study the control algorithm, we have developed a simulation software for the segmented petaloid mirrors. This simulator calculates the vertical position differences between the segments at the 60 displacement sensors based on the three-dimensional movements of the 54 actuators, and enables us to test the control algorithms under various conditions including random noise on the displacement sensors, random movement errors of the actuators, and unexpected lateral shifts of the segments. The outputs of the simulator are not only the phase error of the primary mirror but also the PSF image, taking the structure function of the optical surfaces into account. Using a singular value decomposition method, we found that the 18 petal-shaped segments are controllable within the required displacement errors of 15 nm under the following three conditions: 1) the displacement measurement sensors are placed in staggered fashion between segments, 2) the displacement measurement sensors are axisymmetrically placed with respect to the optical axis, and 3) the relative lateral shift and rotation of each segment are less than 500 μm and 0.05 degree, respectively. In this report, the control algorithm, requirements for the layout of the displacement measurement sensors, and the simulated performance will be presented.

  4. FAME: Freeform Active Mirrors Experiment: manufacturing process development

    Science.gov (United States)

    Challita, Zalpha; Hugot, Emmanuel; Venema, Lars; Schnetler, Hermine; Ferrari, Marc; Cuby, Jean-Gabriel

    2014-07-01

    Extreme freeform mirrors couple a non-axisymmetrical shape and an extreme asphericity, i.e. more than one millimeter of deviation from the best fit sphere. In astronomical instrumentation, such a large asphericity allows compact instruments, using less optical components. However, the lack of freeform mirrors manufacturing facilities is a real issue. We present the concept and development of an innovative manufacturing process based on plasticity forming which allow imprinting permanent deformations on mirrors, following a pre-defined mold. The aim of this activity, pursued in the frame of the OPTICON-FAME (Freeform Active Mirrors Experiment) project, is to demonstrate the suitability of this method for VIS/NIR/MIR applications. The process developed can operate on thin and flat polished initial substrates. Three study cases have been highlighted by FEA (Finite Element Analysis) and the real tests associated were performed on thin substrates in AISI420b stainless steel with 100 mm optical diameter. A comparison between FEA and tests is performed to study the evolution of the mechanical behaviour and the optical quality. The opto-mechanical results will allow a fine tuning of FEA parameters to optimize the residual form errors obtained through this process to converge toward an innovative and recurrent process.

  5. Axisymmetric arc in a supersonic nozzle

    International Nuclear Information System (INIS)

    Axisymmetric arc burning in a supersonic nozzle has wide technical applications (eg in gas blast circuit breaker, arc heaters etc.). Mathematical modelling of such an arc is usually based on boundary-layer assumption which assumes a known pressure distribution imposed on the arc or based on the integral method of arc analysis. Thus, the flow outside of the arc's thermal influence is assumed to be one dimensional. In practice, this is not the case as the nozzle is not sufficiently gentle in the axial direction or the presence of the upstream electrode makes the assumption of one-dimensional flow invalid. The purpose of the present investigation is to model the arc based on Navier-Stokes equations which are modified to take into account of electrical power input and radiation transport. The arcing gas is SF6, the transport properties of which (electrical conductivity, viscosity, thermal conductivity etc.) are highly nonlinear functions of temperature but only weakly dependent on the pressure

  6. Lagrangian mixing in an axisymmetric hurricane model

    Directory of Open Access Journals (Sweden)

    B. Rutherford

    2009-09-01

    Full Text Available This paper discusses the extension of established Lagrangian mixing measures to make them applicable to data extracted from a 2-D axisymmetric hurricane simulation. Because of the non-steady and unbounded characteristics of the simulation, the previous measures are extended to a moving frame approach to create time-dependent mixing rates that are dependent upon the initial time of particle integration, and are computed for nonlocal regions. The global measures of mixing derived from finite-time Lyapunov exponents, relative dispersion, and a measured mixing rate are applied to distinct regions representing different characteristic feautures within the model. It is shown that these time-dependent mixing rates exhibit correlations with maximal tangential winds during a quasi-steady state, establishing a connection between mixing and hurricane intensity.

  7. Carbon nanotube optical mirrors

    Science.gov (United States)

    Chen, Peter C.; Rabin, Douglas

    2015-01-01

    We report the fabrication of imaging quality optical mirrors with smooth surfaces using carbon nanotubes (CNT) embedded in an epoxy matrix. CNT/epoxy is a multifunctional composite material that has sensing capabilities and can be made to incorporate self-actuation. Moreover, as the precursor is a low density liquid, large and lightweight mirrors can be fabricated by processes such as replication, spincasting, and three-dimensional printing. Therefore, the technology holds promise for the development of a new generation of lightweight, compact "smart" telescope mirrors with figure sensing and active or adaptive figure control. We report on measurements made of optical and mechanical characteristics, active optics experiments, and numerical modeling. We discuss possible paths for future development.

  8. Smart materials optical mirrors

    Science.gov (United States)

    Chen, Peter C.; Rabin, Douglas M.

    2014-08-01

    We report the fabrication of imaging quality optical mirrors with smooth surfaces using carbon nanotubes embedded in an epoxy matrix. CNT/epoxy is a multifunctional or `smart' composite material that has sensing capabilities and can be made to incorporate self-actuation as well. Moreover, since the precursor is a low density liquid, large and lightweight mirrors can be fabricated by processes such as replication, spincasting, and 3D printing. The technology therefore holds promise for development of a new generation of lightweight, compact `smart' telescope mirrors with figure sensing and active or adaptive figure control. We report on measurements made of optical and mechanical characteristics. We discuss possible paths for future development.

  9. Distributed actuator deformable mirror

    CERN Document Server

    Bonora, Stefano

    2010-01-01

    In this paper we present a Deformable Mirror (DM) based on the continuous voltage distribution over a resistive layer. This DM can correct the low order aberrations (defocus, astigmatism, coma and spherical aberration) using three electrodes with nine contacts leading to an ideal device for sensorless applications. We present a mathematical description of the mirror, a comparison between the simulations and the experimental results. In order to demonstrate the effectiveness of the device we compared its performance with the one of a multiactuator DM of similar properties in the correction of an aberration statistics. At the end of the paper an example of sensorless correction is shown.

  10. Unification with mirror fermions

    Directory of Open Access Journals (Sweden)

    Triantaphyllou George

    2014-04-01

    Full Text Available We present a new framework unifying interactions in nature by introducing mirror fermions, explaining the hierarchy between the weak scale and the coupling unification scale, which is found to lie close to Planck energies. A novel process leading to the emergence of symmetry is proposed, which not only reduces the arbitrariness of the scenario proposed but is also followed by significant cosmological implications. Phenomenology includes the probability of detection of mirror fermions via the corresponding composite bosonic states and the relevant quantum corrections at the LHC.

  11. Axisymmetric Plume Simulations with NASA's DSMC Analysis Code

    Science.gov (United States)

    Stewart, B. D.; Lumpkin, F. E., III

    2012-01-01

    A comparison of axisymmetric Direct Simulation Monte Carlo (DSMC) Analysis Code (DAC) results to analytic and Computational Fluid Dynamics (CFD) solutions in the near continuum regime and to 3D DAC solutions in the rarefied regime for expansion plumes into a vacuum is performed to investigate the validity of the newest DAC axisymmetric implementation. This new implementation, based on the standard DSMC axisymmetric approach where the representative molecules are allowed to move in all three dimensions but are rotated back to the plane of symmetry by the end of the move step, has been fully integrated into the 3D-based DAC code and therefore retains all of DAC s features, such as being able to compute flow over complex geometries and to model chemistry. Axisymmetric DAC results for a spherically symmetric isentropic expansion are in very good agreement with a source flow analytic solution in the continuum regime and show departure from equilibrium downstream of the estimated breakdown location. Axisymmetric density contours also compare favorably against CFD results for the R1E thruster while temperature contours depart from equilibrium very rapidly away from the estimated breakdown surface. Finally, axisymmetric and 3D DAC results are in very good agreement over the entire plume region and, as expected, this new axisymmetric implementation shows a significant reduction in computer resources required to achieve accurate simulations for this problem over the 3D simulations.

  12. Rapidly convergent algorithms for 3-D tandem and stellarator equilibria in the paraxial approximation

    Energy Technology Data Exchange (ETDEWEB)

    McNamara, B.

    1984-04-01

    Tandem and stellarator equilibria at high ..beta.. have proved hard to compute and the relaxation methods of Bauer et al., Chodura and Schluter, Hirshman, Strauss, and Pearlstein et al. have been slow to converge. This paper reports an extension of the low-..beta.. analytic method of Pearlstein, Kaiser, and Newcomb to arbitrary ..beta.. for tandem mirrors which converges in 10 to 20 iterations. Extensions of the method to stellarator equilibria are proposed and are very close to the analytic method of Johnson and Greene - the stellarator expansion. Most of the results of all these calculations can be adequately described by low-..beta.. approximations since the MHD stability limits occur at low ..beta... The tandem mirror, having weak curvature and a long central cell, allows finite Larmor radius effects to eliminate most ballooning modes and offers the possibility of really high average ..beta... This is the interest in developing such three-dimensional numerical algorithms.

  13. Surface micromachined scanning mirrors

    DEFF Research Database (Denmark)

    Mattsson, Kent Erik

    Both aluminum cantilever and torsional scanning mirrors have been fabricated and their static and dynamic properties are studied experimentally and theoretically. The experiments showed resonance frequencies in the range of 163 k-Hz - 632 kHz for cantilever beams with Q values between 5 and 11. T...

  14. Mirror Symmetry Constructions

    CERN Document Server

    Clader, Emily

    2014-01-01

    These expository notes are based on lectures by Yongbin Ruan during a special semester on the B-model at the University of Michigan in Winter 2014. They outline and compare the mirror symmetry constructions of Batyrev-Borisov, Hori-Vafa, and Bergland-Hubsch-Krawitz.

  15. Asymmetric and axisymmetric dynamics of tropical cyclones

    Directory of Open Access Journals (Sweden)

    J. Persing

    2013-05-01

    Full Text Available We present the results of idealized numerical experiments to examine the difference between tropical cyclone evolution in three-dimensional (3-D and axisymmetric (AX model configurations. We focus on the prototype problem for intensification, which considers the evolution of an initially unsaturated AX vortex in gradient-wind balance on an f-plane. Consistent with findings of previous work, the mature intensity in the 3-D model is reduced relative to that in the AX model. In contrast with previous interpretations invoking barotropic instability and related horizontal mixing processes as a mechanism detrimental to the spin-up process, the results indicate that 3-D eddy processes associated with vortical plume structures can assist the intensification process by contributing to a radial contraction of the maximum tangential velocity and to a vertical extension of tangential winds through the depth of the troposphere. These plumes contribute significantly also to the azimuthally-averaged heating rate and the corresponding azimuthal-mean overturning circulation. The comparisons show that the resolved 3-D eddy momentum fluxes above the boundary layer exhibit counter-gradient characteristics and are generally not represented properly by the subgrid-scale parameterizations in the AX configuration. The resolved eddy fluxes act to support the contraction and intensification of the maximum tangential winds. The comparisons indicate fundamental differences between convective organization in the 3-D and AX configurations for meteorologically relevant forecast time scales. While the radial and vertical gradients of the system-scale angular rotation provide a hostile environment for deep convection in the 3-D model, with a corresponding tendency to strain the convective elements in the tangential direction, deep convection in the AX model does not suffer this tendency. Also, since during the 3-D intensification process the convection has not yet organized

  16. Cosmology with liquid mirror telescopes

    Science.gov (United States)

    Hogg, David W.; Gibson, Brad K.; Hickson, Paul

    1993-01-01

    Liquid mirrors provide an exciting means to obtain large optical telescopes for substantially lower costs than conventional technologies. The liquid mirror concept has been demonstrated in the lab with the construction of a diffraction limited 1.5 m mirror. The mirror surface, using liquid mercury, forms a perfect parabolic shape when the mirror cell is rotated at a uniform velocity. A liquid mirror must be able to support a heavy mercury load with minimal flexure and have a fundamental resonant frequency that is as high as possible, to suppress the amplitude of surface waves caused by small vibrations transmitted to the mirror. To minimize the transmission of vibrations to the liquid surface, the entire mirror rests on an air bearing. This necessitates the mirror cell being lightweight, due to the limited load capabilities of the air bearing. The mirror components must also have physical characteristics which minimize the effects of thermal expansion with ambient temperature fluctuations in the observatory. In addition, the 2.7 m mirror construction is designed so that the techniques used may be readily extended to the construction of large mirrors. To attain the goals of a lightweight, rigid mirror, a composite laminant construction was used. The mirror consists of a foam core cut to the desired parabolic shape, with an accuracy of a few mm. An aluminum hub serves as an anchor for the foam and skin, and allows precise centering of the mirror on the air bearing and drive system. Several plys of Kevlar, covered in an epoxy matrix, are then applied to the foam. A final layer of pure epoxy is formed by spin casting. This final layer is parabolic to within a fraction of a mm. An aluminum ring bonded to the circumference of the mirror retains the mercury, and incorporates stainless-steel hard-points for the attachment of balance weights.

  17. Derived Categories of BHK Mirrors

    CERN Document Server

    Favero, David

    2016-01-01

    We prove a derived analogue to the results of Borisov, Clarke, Kelly, and Shoemaker on the birationality of Berglund-Hubsch-Krawitz mirrors. Heavily bootstrapping off work of Seidel and Sheridan, we obtain Homological Mirror Symmetry for Berglund-Hubsch-Krawitz mirror pencils to hypersurfaces in projective space.

  18. Non-axisymmetric, scale-free, razor-thin discs

    CERN Document Server

    Syer, D; Syer, Dave; Tremaine, Scott

    1996-01-01

    Galaxies exhibit a variety of non-axisymmetric structure (bars, spiral structure, lopsided structure, etc.). These suggest the following general problem: what are the possible stationary configurations of a two-dimensional self-gravitating fluid other than an axisymmetric razor-thin disc? We address a modest component of this problem: we seek non-axisymmetric razor-thin discs of two-dimensional barotropic fluid that are stationary in an inertial frame. We distinguish between `razor-thin' and `two-dimensional,' applying the latter term to the equation of state. Furthermore we assume that our systems are scale-free, which reduces the partial differential equations describing the system to ordinary differential equations. We also allow for the presence of an axisymmetric background potential. This simple and highly idealized problem already exhibits a rich variety of solutions, the richest being for m=1 symmetry.

  19. Axisymmetric Vortex Simulations with Various Turbulence Models

    Directory of Open Access Journals (Sweden)

    Brian Howard Fiedler

    2010-10-01

    Full Text Available The CFD code FLUENTTM has been applied to a vortex within an updraft above a frictional lower boundary. The sensitivity of vortex intensity and structure to the choice of turbulent model is explored. A high Reynolds number of 108 is employed to make the investigation relevant to the atmospheric vortex known as a tornado. The simulations are axisymmetric and are integrated forward in time to equilibrium.  In a variety of turbulence models tested, the Reynolds Stress Model allows for the greatest intensification of the vortex, with the azimuthal wind speed near the surface being 2.4 times the speed of the updraft, consistent with the destructive nature of tornadoes.  The Standard k-e Model, which is simpler than the Reynolds Stress Model but still more detailed than what is commonly available in numerical weather prediction models, produces an azimuthal wind speed near the surface of at most 0.6 times the updraft speed.        

  20. Magnetic surfaces in an axisymmetric torus

    International Nuclear Information System (INIS)

    A method is developed for specifying the boundary equilibrium magnetic surface in an axially symmetric torus by using the absolute values of the magnetic field B = Bs(θ) and the gradient of the poloidal flux vertical bar vertical bar ∇Ψ vertical bar = vertical bar ∇Ψ vertical bar s(θ) in a special flux coordinate system. By setting two surface constants (e.g., the safety factor q and dp/dΨ) and matching the absolute values of the magnetic field and the flux gradient on a closed magnetic surface, it is possible to find all equilibrium magnetic functions (including n · ∇ ln B and the local shear s) and all constants (including the toroidal current J and the shear dμ/dΨ) on this surface. Such a non-traditional formulation of the boundary conditions in solving the stability problem in an axisymmetric torus allows one to impose intentional conditions on plasma confinement and MHD stability at the periphery of the system.

  1. Axisymmetric fully spectral code for hyperbolic equations

    CERN Document Server

    Macedo, Rodrigo P

    2014-01-01

    We present a fully pseudo-spectral scheme to solve axisymmetric hyperbolic equations of second order. With the Chebyshev polynomials as basis functions, the numerical grid is based on the Lobbato (for two spatial directions) and Radau (for the time direction) collocation points. The method solves two issues of previous algorithms which were restricted to one spatial dimension, namely, (i) the inversion of a dense matrix and (ii) the acquisition of a sufficiently good initial-guess for non-linear systems of equations. For the first issue, we use the iterative bi-conjugate gradient stabilized method, which we equip with a pre-conditioner based on a singly diagonally implicit Runge-Kutta ("SDIRK"-) method. The SDIRK-method also supplies the code with a good initial-guess. The numerical solutions are correct up to machine precision and we do not observe any restriction concerning the time step in comparison with the spatial resolution. As an application, we solve general-relativistic wave equations on a black-hol...

  2. Axisymmetric, Ventilated Supercavitation in Unsteady, Horizontal Flow

    Science.gov (United States)

    Kawakami, Ellison; Lee, Seung-Jae; Arndt, Roger

    2012-11-01

    Drag reduction and/or speed augmentation of marine vehicles by means of supercavitation is a topic of great interest. During the initial launch of a supercavitating vehicle, an artificial supercavity is required until the vehicle can reach conditions at which a natural supercavity can be sustained. Previous studies at Saint Anthony Falls Laboratory (SAFL) focused on the behavior of ventilated supercavities in steady horizontal flows. In open waters, vehicles can encounter unsteady flows, especially when traveling under waves. A study has been carried out at SAFL to investigate the effects of unsteady flow on axisymmetric supercavities. An attempt is made to duplicate sea states seen in open waters. In an effort to track cavity dimensions throughout a wave cycle, an automated cavity tracking script has been developed. Using a high speed camera and the proper software, it is possible to synchronize cavity dimensions with pressure measurements taken inside the cavity. Results regarding supercavity shape, ventilation demand, cavitation parameters and closure methods are presented. It was found that flow unsteadiness caused a decrease in the overall length of the supercavity while having only a minimal effect on the maximum diameter. The supercavity volume varied with cavitation number and a possible relationship between the two is being explored. (Supported by ONR)

  3. Numerical Strategies for Stroke Optimization of Axisymmetric Microswimmers

    CERN Document Server

    Alouges, François; Heltai, Luca

    2009-01-01

    We propose a computational method to solve optimal swimming problems, based on the boundary integral formulation of the hydrodynamic interaction between swimmer and surrounding fluid and direct constrained minimization of the energy consumed by the swimmer. We apply our method to axisymmetric model examples. We consider a classical model swimmer (the three-sphere swimmer of Golestanian et al.) as well as a novel axisymmetric swimmer inspired by the observation of biological micro-organisms.

  4. Artificial boundary conditions for axisymmetric eddy current probe problems

    OpenAIRE

    Haddar, Houssem; Jiang, Zixian; Lechleiter, Armin

    2015-01-01

    We study different strategies for the truncation of computational domains in the simulation of eddy current probes of elongated axisymmetric tubes. For axial fictitious boundaries, an exact Dirichlet-to-Neumann map is proposed and mathematically analyzed via a non-selfadjoint spectral problem: under general assumptions we show convergence of the solution to an eddy current problem involving a truncated Dirichlet-to-Neumann map to the solution on the entire, unbounded axisymmetric domain as th...

  5. Some aspects of the axisymmetric wall-jet analysis

    Czech Academy of Sciences Publication Activity Database

    Kolář, Václav

    Istanbul : WSEAS Press, 2012 - (Mastny, P.; Perminov, V.), s. 317-320 ISBN 978-1-61804-114-2. ISSN 2227-4596. - (Recent Advances in Mechanical Engineering Series. 1). [WSEAS International Conference on Fluid Mechanics & Aerodynamics /10./ (FMA '12). Istanbul (TR), 21.08.2012-23.08.2012] R&D Projects: GA AV ČR IAA200600801 Institutional support: RVO:67985874 Keywords : axisymmetric wall jets * flow past axisymmetric bodies * similarity solution * swirl Subject RIV: BK - Fluid Dynamics

  6. Mirror, Mirror, On The Wall: Collaborative Screen-Mirroring for Small Groups

    OpenAIRE

    McGill, Mark; Williamson, John; Brewster, Stephen A.

    2014-01-01

    Screen mirroring has been available to consumers for some time, however if every mobile device in the room supports screen mirroring to the main display (e.g. a shared TV), this necessitates a mechanism for managing its use. As such, this paper investigates allowing users in small intimacy groups (friends, family etc.) to self-manage mirrored use of the display, through passing/taking/requesting the display from whomever is currently mirroring to it. We examine the collaborative benefits this...

  7. 10 years Rossendorf Tandem

    International Nuclear Information System (INIS)

    10 years successful operation of the Rossendorf Tandem is an occasion to give an account about the most important developments and results in the fields of accelerator technology and utilization of this machine. The selected and sum up contributions reflect the systematic orientation on increasing the availability of the accelerator as well as its improvement to an effective heavy ion accelerator to extend the quantitative and qualitative possibilities of application in nuclear physical experiments. (author)

  8. Tandem physics in Orsay

    International Nuclear Information System (INIS)

    An account is given of the very good and reliable running of the Orsay MP tandem accelerator at 13MeV. The experimental equipment is briefly described and a summary of the scientific program is given, illustrated by a few chosen examples in each main domain of research: spectroscopy by transfer reactions, angular correlations and γ-desexcitation, mechanisms of the scattering in symmetrical systems and polarization in heavy ions reactions, studies of exotic nuclei

  9. Lightweight in-plane actuated deformable mirrors for space telescopes

    Science.gov (United States)

    Shepherd, Michael J.

    This research focused on lightweight, in-plane actuated, deformable mirrors, with the ultimate goal of developing a 20-meter or larger diameter light gathering aperture for space telescopes. Membrane optics is the study of these structures which may be stowed compactly and unfurled in orbit. This effort comprised four research areas: modelling, analytical solutions, surface control strategy, and scaling. Initially, experimental results were compared to theory using a 0.127 meter diameter deformable mirror testbed. The mirror was modelled using finite elements with MSC.Nastran software, where a boundary tension field was determined using laser vibrometer data. A non-linear solution technique was used to incorporate the membrane stiffening from the applied tension. Statically obtained actuator influence functions were compared to experimentally achieved data, and then a least squares approach was used as the basis for creating a quasi-static control algorithm. Experimental simultaneous tracking of Zernike tip, tilt, and defocus modes was successfully demonstrated. The analytical solutions to plate-membrane and beam-string ordinary differential equation representing the deformable mirror equations were developed. A simplified approach to modelling the axisymmetric cases was also presented. Significantly, it was shown both analytically and through numerical analysis that static actuation for a mirror with a discrete electrode pattern and a high tension-to-stiffness ratio was simply a localized piston displacement in the region of the actuator. Next, a novel static control strategy, the Modal Transformation Method, was developed for membrane mirrors. The method was implemented in finite element simulation, and shows the capability of the in-plane actuated mirror to form Zernike surfaces within an interior, or clear aperture, region using a number of statically-actuated structural modes. Lastly, the scaling problem for membrane optics was addressed. Linear modelling was

  10. Dynamic coherent backscattering mirror

    Energy Technology Data Exchange (ETDEWEB)

    Zeylikovich, I.; Xu, M., E-mail: mxu@fairfield.edu [Physics Department, Fairfield University, Fairfield, CT 06824 (United States)

    2016-02-15

    The phase of multiply scattered light has recently attracted considerable interest. Coherent backscattering is a striking phenomenon of multiple scattered light in which the coherence of light survives multiple scattering in a random medium and is observable in the direction space as an enhancement of the intensity of backscattered light within a cone around the retroreflection direction. Reciprocity also leads to enhancement of backscattering light in the spatial space. The random medium behaves as a reciprocity mirror which robustly converts a diverging incident beam into a converging backscattering one focusing at a conjugate spot in space. Here we first analyze theoretically this coherent backscattering mirror (CBM) phenomenon and then demonstrate the capability of CBM compensating and correcting both static and dynamic phase distortions occurring along the optical path. CBM may offer novel approaches for high speed dynamic phase corrections in optical systems and find applications in sensing and navigation.

  11. Skin mirrors human aging.

    Science.gov (United States)

    Nikolakis, Georgios; Makrantonaki, Evgenia; Zouboulis, Christos C

    2013-12-01

    Abstract Aged skin exhibits disturbed lipid barrier, angiogenesis, production of sweat, immune functions, and calcitriol synthesis as well as the tendency towards development of certain benign or malignant diseases. These complex biological processes comprise endogenous and exogenous factors. Ethnicity also markedly influences the phenotype of skin aging. The theories of cellular senescence, telomere shortening and decreased proliferative capacity, mitochondrial DNA single mutations, the inflammation theory, and the free radical theory try to explain the biological background of the global aging process, which is mirrored in the skin. The development of advanced glycation end-products and the declining hormonal levels are major factors influencing intrinsic aging. Chronic photodamage of the skin is the prime factor leading to extrinsic skin aging. The deterioration of important skin functions, due to intrinsic and extrinsic aging, leads to clinical manifestations, which mirror several internal age-associated diseases such as diabetes, arterial hypertension and malignancies. PMID:25436743

  12. Mirror Fusion Test Facility

    International Nuclear Information System (INIS)

    On October 1, 1977 work began at LLL on the Mirror Fusion Test Facility (MFTF), an advanced experimental fusion device. Scheduled for operation in late 1981, MFTF is designed as an intermediate step between present mirror machines, such as 2XIIB, and an experimental fusion reactor. This design incorporates improved technology and a better theoretical understanding of how neutral beam injection, plasma guns, and gas injection into the plasma region compensate for cooling and particle losses. With the new facility, we expect to achieve a confinement factor (n tau) of 1012 particles . sm/cm3--a tenfold increase over 2XIIB n tau values--and to increase plasma temperature to over 500 million K. The following article describes this new facility and reports on progress in some of the R and D projects that are providing the technological base for its construction

  13. Ion Acceleration in Plasmas Emerging from a Helicon-heated Magnetic-mirror Device

    International Nuclear Information System (INIS)

    Using laser-induced fluorescence, measurements have been made of metastable argon-ion, Ar+*(3d4 f7/2), velocity distributions on the major axis of an axisymmetric magnetic-mirror device whose plasma is sustained by helicon wave absorption. Within the mirror, these ions have sub-eV temperature and, at most, a subthermal axial drift. In the region outside the mirror coils, conditions are found where these ions have a field-parallel velocity above the acoustic speed, to an axial energy of ∼30 eV, while the field-parallel ion temperature remains low. The supersonic Ar+*(3d4 f7/2) are accelerated to one-third of their final energy within a short region in the plasma column, (le)1 cm, and continue to accelerate over the next 5 cm. Neutral gas density strongly affects the supersonic Ar+*(3d4 f7/2) density

  14. Complex/Symplectic Mirrors

    CERN Document Server

    Chuang, W; Tomasiello, A; Chuang, Wu-yen; Kachru, Shamit; Tomasiello, Alessandro

    2005-01-01

    We construct a class of symplectic non--Kaehler and complex non--Kaehler string theory vacua, extending and providing evidence for an earlier suggestion by Polchinski and Strominger. The class admits a mirror pairing by construction. Comparing hints from a variety of sources, including ten--dimensional supergravity and KK reduction on SU(3)--structure manifolds, suggests a picture in which string theory extends Reid's fantasy to connect classes of both complex non-Kaehler and symplectic non-Kaehler manifolds.

  15. Complex/Symplectic Mirrors

    International Nuclear Information System (INIS)

    We construct a class of symplectic non-Kaehler and complex non-Kaehler string theory vacua, extending and providing evidence for an earlier suggestion by Polchinski and Strominger. The class admits a mirror pairing by construction. Comparing hints from a variety of sources, including ten-dimensional supergravity and KK reduction on SU(3)-structure manifolds, suggests a picture in which string theory extends Reid's fantasy to connect classes of both complex non-Kaehler and symplectic non-Kaehler manifolds

  16. Neutral beams for mirrors

    International Nuclear Information System (INIS)

    An important demonstration of negative ion technology is proposed for FY92 in the MFTF-α+T, an upgrade of the Mirror Fusion Test Facility at the Lawrence Livermore National Laboratory. This facility calls for 200-keV negative ions to form neutral beams that generate sloshing ions in the reactor end plugs. Three different beam lines are considered for this application. Their advantages and disadvantages are discussed

  17. Lightweight Substrates For Mirrors

    Science.gov (United States)

    Brown, D. Kyle

    1991-01-01

    New substrate uses conventional quasi-isotropic fabric laminate with surfacing layer of carbon-fiber paper consisting of randomly oriented chopped carbon fibers. Layered structure of fabric and paper relatively easy to manufacture. When impregnated with carbon, structure rigid and stable. Substrates of this type made quite thin, thus keeping areal weights to minimum. Mirrors of this type made faster, and cost less, than predecessors.

  18. Mirror dark matter discovered?

    OpenAIRE

    Silagadze, Z. K.

    2008-01-01

    Recent astrophysical data indicates that dark matter shows a controversial behaviour in galaxy cluster collisions. In case of the notorious Bullet cluster, dark matter component of the cluster behaves like a collisionless system. However, its behaviour in the Abell 520 cluster indicates a significant self-interaction cross-section. It is hard for the WIMP based dark matter models to reconcile such a diverse behaviour. Mirror dark matter models, on the contrary, are more flexible and for them ...

  19. Axisymmetric Control in Alcator C-Mod

    Science.gov (United States)

    Tinios, Gerasimos

    1995-01-01

    This thesis investigates the degree to which linear axisymmetric modeling of the response of a tokamak plasma can reproduce observed experimental behavior. The emphasis is on the vertical instability. The motivation for this work lies in the fact that, once dependable models have been developed, modern control theory methods can be used to design feedback laws for more effective and efficient tokamak control. The models are tested against experimental data from the Alcator C-Mod tokamak. A linear model for each subsystem of the closed-loop system constituting an Alcator C-Mod discharge under feedback control has been constructed. A non-rigid, approximately flux-conserving, perturbed equilibrium plasma response model is used in the comparison to experiment. A detailed toroidally symmetric model of the vacuum vessel and the supporting superstructure is used. Modeling of the power supplies feeding the active coils has been included. Experiments have been conducted with vertically unstable plasmas where the feedback was turned off and the plasma response was observed in an open -loop configuration. The closed-loop behavior has been examined by injecting step perturbations into the desired vertical position of the plasma. The agreement between theory and experiment in the open-loop configuration was very satisfactory, proving that the perturbed equilibrium plasma response model and a toroidally symmetric electromagnetic model of the vacuum vessel and the structure can be trusted for the purpose of calculations for control law design. When the power supplies and the feedback computer hardware are added to the system, however, as they are in the closed-loop configuration, they introduce nonlinearities that make it difficult to explain observed behavior with linear theory. Nonlinear simulation of the time evolution of the closed-loop experiments was able to account for the discrepancies between linear theory and experiment. (Copies available exclusively from MIT Libraries

  20. Report of the workshop on rf heating in mirror systems

    International Nuclear Information System (INIS)

    This report is prepared from the proceedings of the Workshop on RF Heating in Magnetic Mirror Systems held at DOE Headquarters in Washington, DC, on March 10-12, 1980. The workshop was organized into four consecutive half-day sessions of prepared talks and one half-day discussion. The first session on tandem mirror concepts and program plans served to identify the opportunities for the application of rf power and the specific approaches that are being pursued. A summary of the ideas presented in this session is given. The following sessions of the workshop were devoted to an exposition of current theoretical and experimental knowledge on the interaction of rf power with magnetically confined, dense, high temperature plasmas at frequencies near the electron cyclotron resonance, lower hybrid resonance and ion cyclotron resonance (including magnetosonic) ranges. The conclusions from these proceedings are presented

  1. A Mirroring Theorem and its Application to a New Method of Unsupervised Hierarchical Pattern Classification

    CERN Document Server

    Deepthi, Dasika Ratna

    2009-01-01

    In this paper, we prove a crucial theorem called Mirroring Theorem which affirms that given a collection of samples with enough information in it such that it can be classified into classes and subclasses then (i) There exists a mapping which classifies and subclassifies these samples (ii) There exists a hierarchical classifier which can be constructed by using Mirroring Neural Networks (MNNs) in combination with a clustering algorithm that can approximate this mapping. Thus, the proof of the Mirroring theorem provides a theoretical basis for the existence and a practical feasibility of constructing hierarchical classifiers, given the maps. Our proposed Mirroring Theorem can also be considered as an extension to Kolmogrovs theorem in providing a realistic solution for unsupervised classification. The techniques we develop, are general in nature and have led to the construction of learning machines which are (i) tree like in structure, (ii) modular (iii) with each module running on a common algorithm (tandem a...

  2. Superconducting (radiation hardened) magnets for mirror fusion devices

    International Nuclear Information System (INIS)

    Superconducting magnets for mirror fusion have evolved considerably since the Baseball II magnet in 1970. Recently, the Mirror Fusion Test Facility (MFTF-B) yin-yang has been tested to a full field of 7.7 T with radial dimensions representative of a full scale reactor. Now the emphasis has turned to the manufacture of very high field solenoids (choke coils) that are placed between the tandem mirror central cell and the yin-yang anchor-plug set. For MFTF-B the choke coil field reaches 12 T, while in future devices like the MFTF-Upgrade, Fusion Power Demonstration and Mirror Advanced Reactor Study (MARS) reactor the fields are doubled. Besides developing high fields, the magnets must be radiation hardened. Otherwise, thick neutron shields increase the magnet size to an unacceptable weight and cost. Neutron fluences in superconducting magnets must be increased by an order of magnitude or more. Insulators must withstand 1010 to 1011 rads, while magnet stability must be retained after the copper has been exposed to fluence above 1019 neutrons/cm2

  3. Variable focal length deformable mirror

    Science.gov (United States)

    Headley, Daniel; Ramsey, Marc; Schwarz, Jens

    2007-06-12

    A variable focal length deformable mirror has an inner ring and an outer ring that simply support and push axially on opposite sides of a mirror plate. The resulting variable clamping force deforms the mirror plate to provide a parabolic mirror shape. The rings are parallel planar sections of a single paraboloid and can provide an on-axis focus, if the rings are circular, or an off-axis focus, if the rings are elliptical. The focal length of the deformable mirror can be varied by changing the variable clamping force. The deformable mirror can generally be used in any application requiring the focusing or defocusing of light, including with both coherent and incoherent light sources.

  4. Bifacial tandem solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Wojtczuk, Steven J.; Chiu, Philip T.; Zhang, Xuebing; Gagnon, Edward; Timmons, Michael

    2016-06-14

    A method of fabricating on a semiconductor substrate bifacial tandem solar cells with semiconductor subcells having a lower bandgap than the substrate bandgap on one side of the substrate and with subcells having a higher bandgap than the substrate on the other including, first, growing a lower bandgap subcell on one substrate side that uses only the same periodic table group V material in the dislocation-reducing grading layers and bottom subcells as is present in the substrate and after the initial growth is complete and then flipping the substrate and growing the higher bandgap subcells on the opposite substrate side which can be of different group V material.

  5. Axisymmetric modes of rotating relativistic stars in the cowling approximation

    International Nuclear Information System (INIS)

    Axisymmetric pulsations of rotating neutron stars can be excited in several scenarios, such as core-collapse, crust and core-quakes and binary mergers and could become detectable either in gravitational waves or high-energy radiation. Here, we present a comprehensive study of all low-order axisymmetric modes of uniformly and rapidly rotating relativistic stars. Initial stationary configurations are appropriately perturbed and are numerically evolved using an axisymmetric, nonlinear relativistic hydrodynamics code, assuming time-independence of the gravitational field (Cowling approximation). The simulations are performed using a high-resolution shock-capturing finite-difference scheme accurate enough to maintain the initial rotation law for a large number of rotational periods, even for stars at the mass-shedding limit. Through Fourier transforms of the time evolution of selected fluid variables, we compute the frequencies of quasi-radial and non-radial modes with spherical harmonic indices l=0, 1, 2 and 3, for a sequence of rotating stars from the non-rotating limit to the mass-shedding limit. The frequencies of the axisymmetric modes are affected significantly by rotation only when the rotation rate exceeds about 50% of the maximum allowed. As expected, at large rotation rates, apparent mode crossings between different modes appear. In addition to the above modes, several axisymmetric inertial modes are also excited in our numerical evolutions. (orig.)

  6. Stationary and axisymmetric solutions of higher-dimensional general relativity

    International Nuclear Information System (INIS)

    We study stationary and axisymmetric solutions of General Relativity, i.e., pure gravity, in four or higher dimensions. D-dimensional stationary and axisymmetric solutions are defined as having D-2 commuting Killing vector fields. We derive a canonical form of the metric for such solutions that effectively reduces the Einstein equations to a differential equation on an axisymmetric D-2 by D-2 matrix field living in three-dimensional flat space (apart from a subclass of solutions that instead reduce to a set of equations on a D-2 by D-2 matrix field living in two-dimensional flat space). This generalizes the Papapetrou form of the metric for stationary and axisymmetric solutions in four dimensions, and furthermore generalizes the work on Weyl solutions in four and higher dimensions. We analyze then the sources for the solutions, which are in the form of thin rods along a line in the three-dimensional flat space that the matrix field can be seen to live in. As examples of stationary and axisymmetric solutions, we study the five-dimensional rotating black hole and the rotating black ring, write the metrics in the canonical form and analyze the structure of the rods for each solution

  7. Complex/Symplectic Mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Chuang, Wu-yen; Kachru, Shamit; /Stanford U., ITP /SLAC; Tomasiello, Alessandro; /Stanford U., ITP

    2005-10-28

    We construct a class of symplectic non-Kaehler and complex non-Kaehler string theory vacua, extending and providing evidence for an earlier suggestion by Polchinski and Strominger. The class admits a mirror pairing by construction. Comparing hints from a variety of sources, including ten-dimensional supergravity and KK reduction on SU(3)-structure manifolds, suggests a picture in which string theory extends Reid's fantasy to connect classes of both complex non-Kaehler and symplectic non-Kaehler manifolds.

  8. Plane SPDC-Quantum Mirror

    OpenAIRE

    Ion, M. L. D.; Ion, D. B.

    2013-01-01

    In this paper the kinematical correlations from the phase conjugated optics (equivalently with crossing symmetric spontaneous parametric down conversion (SPDC) phenomena) in the nonlinear crystals are used for the description of a new kind of optical device called SPDC-quantum mirrors. Then, some important laws of the plane SPDC-quantum mirrors combined with usual mirrors or lens are proved only by using geometric optics concepts. In particular, these results allow us to obtain a new interpre...

  9. Trieste lectures on mirror symmetry

    International Nuclear Information System (INIS)

    These are pedagogical lectures on mirror symmetry given at the Spring School in ICTP, Trieste, March 2002. The focus is placed on worldsheet descriptions of the physics related to mirror symmetry. We start with the introduction to general aspects of (2,2) supersymmetric field theories in 1 + 1 dimensions. We next move on to the study and applications of linear sigma model. Finally, we provide a proof of mirror symmetry in a class of models. (author)

  10. Modification of the Argonne tandem

    International Nuclear Information System (INIS)

    For nuclear structure experiments with heavy ions it is necessary to have ion energies in excess of 5 MeV per nucleon. At the Argonne tandem FN accelerator this was accomplished by the addition of a superconducting linac. Modifications of the FN tandem to improve the performance of the pair is described

  11. Near surface stress analysis strategies for axisymmetric fretting

    Indian Academy of Sciences (India)

    M Ramesh; Satish V Kailas; K R Y Simha

    2008-06-01

    Fretting is essentially a surface phenomenon, but bulk stresses and material properties contribute to subsequent failure. This feature of fretting demands a thorough understanding of near surface stresses under the joint action of normal, shear and thermal loading. Axisymmetric fretting is of great concern in piping and coupling design. In this paper, we develop design tools for Near Surface Analysis (NSA) for understanding axisymmetric fretting. Axisymmetric Fretting Analysis (AFA) becomes formidable owing to localised tractions that call for Fourier transform techniques. We develop two different NSA strategies based on two-dimensional plane strain models: 2D strip model (2DS) and half-plane Flamant model (2DF). We compare the results of 2DS and 2DF with the exact results for AFA obtained using Love’s stress function in conjunction with Fourier transform. There is a good correspondence between stress components obtained from 2D-models.

  12. Axisymmetric Modes of Rotating Relativistic Stars in the Cowling Approximation

    CERN Document Server

    Font, J A; Sen-Gupta, A; Stergioulas, N; Font, Jose A.; Dimmelmeier, Harald; Gupta, Anshu; Stergioulas, Nikolaos

    2001-01-01

    Axisymmetric pulsations of rotating neutron stars can be excited in several scenarios, such as core-collapse, crust and core-quakes and binary mergers and could become detectable either in gravitational waves or high-energy radiation. Here, we present a comprehensive study of all low-order axisymmetric modes of uniformly and rapidly rotating relativistic stars. Initial stationary configurations are appropriately perturbed and are numerically evolved using an axisymmetric, nonlinear relativistic hydrodynamics code, assuming time-independence of the gravitational field (Cowling approximation). The simulations are performed using a high-resolution shock-capturing finite-difference scheme accurate enough to maintain the initial rotation law for a large number of rotational periods, even for stars at the mass-shedding limit. Through Fourier transforms of the time evolution of selected fluid variables, we compute the frequencies of quasi-radial and non-radial modes with spherical harmonic indices l=0,1,2 and 3, for...

  13. Superconductivity for mirror fusion

    International Nuclear Information System (INIS)

    Mirror experiments have led the way in applying superconductivity to fusion research because of unique requirements for high and steady magnetic fields. The first significant applications were Baseball II at LLL and IMP at ORNL, which used multifilamentary niobium--titanium and niobium--tin tape, respectively. Now the USSR at Kurchatov is building a smaller baseball coil with a 6.5 mm square multifilamentary niobium--titanium superconductor similar to the Baseball II conductor. However, the largest advance in fusion magnets will be used in the Mirror Fusion Test Facility (MFTF) now under construction at LLL. Improvements in the technology of the previous LLL experiment, Baseball II, have been made using new conductor joining techniques, a ventilated wrap-around copper stabilizer, and stronger structural welding methods. The MFTF coil winding is proceeding on a separate former to allow parallel construction of the main structure. Not only does this shorten the project schedule to equal that of other conventional constructions, but a second vacuum barrier is created between the magnet helium and the plasma environment for reliable operation

  14. Study of axisymmetric flow problems by Hele-Shaw models

    Science.gov (United States)

    Rao, P. V.; Sachan, J. S.

    1980-05-01

    Hele-Shaw models have been applied for solving two-dimensional, irrotational flow problems such as flow past bodies or radial seepage flow. The gap between the two plates is varied as a cubic parabola in the radial direction. Results are presented for seven axisymmetric models, including a cylindrical body with 60-deg conical head forms, an axisymmetric sluice entrance with a compound elliptical transition and radial flow to a well with a free surface. Pressure distributions were computed and compared with water-tunnel data, wind-tunnel data, finite-differential solutions and exact solutions.

  15. Axisymmetric solitary waves on the surface of a ferrofluid

    CERN Document Server

    Bourdin, Elise; Falcon, Eric

    2010-01-01

    We report the first observation of axisymmetric solitary waves on the surface of a cylindrical magnetic fluid layer surrounding a current-carrying metallic tube. According to the ratio between the magnetic and capillary forces, both elevation and depression solitary waves are observed with profiles in good agreement with theoretical predictions based on the magnetic analogue of the Korteweg-deVries equation. We also report the first measurements of the velocity and the dispersion relation of axisymmetric linear waves propagating on the cylindrical ferrofluid layer that are found in good agreement with theoretical predictions.

  16. Axisymmetric multiphase Lattice Boltzmann method for generic equations of state

    CERN Document Server

    Reijers, Sten A; Toschi, Federico

    2015-01-01

    We present an axisymmetric lattice Boltzmann model based on the Kupershtokh et al. multiphase model that is capable of solving liquid-gas density ratios up to $10^3$. Appropriate source terms are added to the lattice Boltzmann evolution equation to fully recover the axisymmetric multiphase conservation equations. We validate the model by showing that a stationary droplet obeys the Young-Laplace law, comparing the second oscillation mode of a droplet with respect to an analytical solution and showing correct mass conservation of a propagating density wave.

  17. Analytical calculation of boozer magnetic coordinates for axisymmetric MHD equilibria

    International Nuclear Information System (INIS)

    A new analytical technique for extracting the Boozer magnetic coordinates in axisymmetric MHD equilibria is described. The method is based upon the correspondence between the expansion of the flux function in toroidal multipolar moments and the expansion in toroidal axisymmetric harmonics of the magnetic scalar potential χ0, which appears in the covariant representation B=∇χ0+β∇ψ-T of the magnetic field. An example of calculation of Boozer magnetic coordinates is given for an experimental highly shaped high β equilibrium of DIIID

  18. Potential flow past axisymmetric bodies at angle of attack

    Science.gov (United States)

    Kuhlman, J. M.; Shu, J.-Y.

    1984-01-01

    The Karamcheti (1966) suggestion concerning the use of higher order singularity techniques has been developed for the calculation of incompressible flow past an axisymmetric body at angle of attack. Attention is given to the results of a convergence study using this axial singularity method, where solution accuracy has been investigated for ellipsoids of slenderness ratio in the 1-10 range for both axial and inclined flow. Effects of singularity type, element number and size distribution, and singularity line inset distance, are noted, and a paneling scheme is developed which yields accurate results for the class of axisymmetric bodies having continuous body slopes with discontinuous curvature jumps.

  19. Local Axisymmetric Instability Criterion in the Thin, Rotating, Multicomponent Disk

    CERN Document Server

    Rafikov, R R

    2000-01-01

    Purely gravitational perturbations are considered in a thin rotating disk composed of several gas and stellar components. The dispersion relation for the axisymmetric density waves propagating through the disk is found and the criterion for the local axisymmetric stability of the whole system is formulated. In the appropriate limit of two-component gas we confirm the findings of Jog & Solomon (1984) and extend consideration to the case when one component is collisionless. Gravitational stability of the Galactic disk in the Solar neighborhood based on the multicomponent instability condition is explored using recent measurements of the stellar composition and kinematics in the local Galactic disk obtained by Hipparcos satellite.

  20. JAERI tandem-accelerator and tandem-booster

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Tadashi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    In 1982, aiming at the new development of atomic energy research, the tandem accelerator of Japan Atomic Energy Research Institute (JAERI) was installed. In fiscal year 1993, the superconducting boosters which can increase the ion energy by up to 4 times were added, and the research in the region below 1000 MeV became possible. Those are electrostatic type accelerators which are easy to be used especially in basic research field, and are useful for future research. The tandem accelerator has been operated while maintaining the first class performance as the accelerator for various kinds of heavy ion beam. It has the special shape among electrostatic type accelerators, and is excellent in the easiness of control and stability. The main particulars of the tandem accelerator are shown. As for the ion sources of the tandem accelerator, three cesium sputter type ion sources are installed on two high voltage stands. The kinds of the ions which can be accelerated are mainly negative ions. As the improvement, electron cyclotron resonance (ECR) ion sources are expected to be adopted. As for the tandem boosters, the 1/4 wavelength type resonance hollow cylinder was adopted. The constitution of the tandem boosters is explained. The way of utilizing the tandem accelerator system and the aim for hereafter are reported. (K.I.)

  1. Heliostat mirror survey and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lind, M.A.; Buckwalter, C.Q.; Daniel, J.L.; Hartman, J.S.; Thomas, M.T.; Pederson, L.R.

    1979-09-01

    The mirrors used on concentrating solar systems must be able to withstand severe and sustained environmental stresses for long periods of time if they are to be economically acceptable. Little is known about how commercially produced wet process silvered second surface mirrors will withstand the test of time in solar applications. Field experience in existing systems has shown that the performance of the reflective surface varies greatly with time and is influenced to a large extent by the construction details of the mirror module. Degradation of the reflective layer has been seen that ranges from non-observable to severe. The exact mechanisms involved in the degradation process are not well understood from either the phenomenological or microanalytical points of view and are thus subject to much debate. The three chapters of this report summarize the work recently performed in three general areas that are key to understanding and ultimately controlling the degradation phenomena. These areas are: a survey of the present commercial mirroring industry, the microanalytical examination of numerous degraded and nondegraded mirrors, and an investigation of several novel techniques that might be used to extend the life of heliostat mirrors. Appendices include: (a) list of mirror manufacturers and (b) recommended specifications for second surface silvered mirrors for central receiver heliostat applications. (WHK)

  2. Mirror left-right symmetry

    International Nuclear Information System (INIS)

    We propose a novel SU(3)c×SU(2)L×SU(2)R×U(1)B-L left-right symmetric model where the standard model fermion and Higgs fields are SU(2)L doublets or SU(2) singlets while their mirror partners are SU(2)R doublets or SU(2) singlets. The scalar fields also include a real singlet for dark matter and two SU(2) triplets for seesaw. The mixing between the standard model and mirror fermions is forbidden by a Z2×Z2′ discrete symmetry. The mirror charged fermions can decay into their standard model partners with the dark-matter scalar while the mirror neutrinos can decay into the mirror charged fermions through the right-handed gauge interactions. Our model can have new implications on the strong CP problem, leptogenesis, collider phenomenology and dark matter detection.

  3. A regularity criterion for the angular velocity component in axisymmetric Navier-Stokes equations

    OpenAIRE

    Ondrej Kreml; Milan Pokorny

    2007-01-01

    We study the non-stationary Navier-Stokes equations in the entire three-dimensional space under the assumption that the data are axisymmetric. We extend the regularity criterion for axisymmetric weak solutions given in [10].

  4. A regularity criterion for the angular velocity component in axisymmetric Navier-Stokes equations

    Directory of Open Access Journals (Sweden)

    Ondrej Kreml

    2007-01-01

    Full Text Available We study the non-stationary Navier-Stokes equations in the entire three-dimensional space under the assumption that the data are axisymmetric. We extend the regularity criterion for axisymmetric weak solutions given in [10].

  5. The kinaesthetic mirror illusion: How much does the mirror matter?

    Science.gov (United States)

    Chancel, Marie; Brun, Clémentine; Kavounoudias, Anne; Guerraz, Michel

    2016-06-01

    The reflection of a moving hand in a mirror positioned in the sagittal plane can create an illusion of symmetrical, bimanual movement. This illusion is implicitly presumed to be of visual origin. However, muscle proprioceptive afferents of the arm reflected in the mirror might also affect the perceived position and movement of the other arm. We characterized the relative contributions of visual and proprioceptive cues by performing two experiments. In Experiment 1, we sought to establish whether kinaesthetic illusions induced using the mirror paradigm would survive marked visual impoverishment (obtained by covering between 0 and 100 % of the mirror in 16 % steps). We found that the mirror illusion was only significantly influenced when the visual degradation was 84 % or more. In Experiment 2, we masked the muscle proprioceptive afferents of the arm reflected in the mirror by co-vibrating antagonistic muscles. We found that masking the proprioceptive afferents reduced the velocity of the illusory displacement of the other arm. These results confirm that the mirror illusion is not a purely visual illusion but emerges from a combination of congruent signals from the two arms, i.e. visual afferents from the virtually moving arm and proprioceptive afferents from the contralateral, moving arm. PMID:26790422

  6. Consistent lattice Boltzmann methods for incompressible axisymmetric flows

    Science.gov (United States)

    Zhang, Liangqi; Yang, Shiliang; Zeng, Zhong; Yin, Linmao; Zhao, Ya; Chew, Jia Wei

    2016-08-01

    In this work, consistent lattice Boltzmann (LB) methods for incompressible axisymmetric flows are developed based on two efficient axisymmetric LB models available in the literature. In accord with their respective original models, the proposed axisymmetric models evolve within the framework of the standard LB method and the source terms contain no gradient calculations. Moreover, the incompressibility conditions are realized with the Hermite expansion, thus the compressibility errors arising in the existing models are expected to be reduced by the proposed incompressible models. In addition, an extra relaxation parameter is added to the Bhatnagar-Gross-Krook collision operator to suppress the effect of the ghost variable and thus the numerical stability of the present models is significantly improved. Theoretical analyses, based on the Chapman-Enskog expansion and the equivalent moment system, are performed to derive the macroscopic equations from the LB models and the resulting truncation terms (i.e., the compressibility errors) are investigated. In addition, numerical validations are carried out based on four well-acknowledged benchmark tests and the accuracy and applicability of the proposed incompressible axisymmetric LB models are verified.

  7. Non-Axisymmetric Shaping of Tokamaks Preserving Quasi-Axisymmetry

    International Nuclear Information System (INIS)

    If quasi-axisymmetry is preserved, non-axisymmetric shaping can be used to design tokamaks that do not require current drive, are resilient to disruptions, and have robust plasma stability without feedback. Suggestions for addressing the critical issues of tokamaks can only be validated when presented with sufficient specificity that validating experiments can be designed. The purpose of this paper is provide that specificity for non-axisymmetric shaping. To our knowledge, no other suggestions for the solution of a number of tokamak issues, such as disruptions, have reached this level of specificity. Sequences of three-field-period quasi-axisymmetric plasmas are studied. These sequences address the questions: (1) What can be achieved at various levels of non-axisymmetric shaping? (2) What simplifications to the coils can be achieved by going to a larger aspect ratio? (3) What range of shaping can be achieved in a single experimental facility? The sequences of plasmas found in this study provide a set of interesting and potentially important configurations.

  8. Unified characteristics line theory of spacial axisymmetric plastic problem

    Institute of Scientific and Technical Information of China (English)

    俞茂宏; 李建春; 张永强

    2001-01-01

    The unified strength theory proposed by Yu in 1991 is extended to spacial axisymmetric problem. A unified spacial axismymmetric characteristics line theory based on the unified strength theory is proposed. This theory takes account of different effects of intermediate principal stress on yielding or failure and the SD effect (tensile-compression strength difference) of materials. Various conventional axisymmetric characteristics line theories, whihc are based on the Haar-von Karman plastic condition, Szczepinski hypothesis, Tresca criterion, von Mises criterion and Mohr-Coulomb theory, are special cases of the new theory. Besides, a series of new spacial axisymmetric characteristics fields for different materials can be introduced. It forms a unified spacial axisymmetric characteristics theory. Two examples are calculated with the new theory, the results are compared with those obtained by the finite element program UEPP and those based on the Mohr-Coulomb strength theory. It is shown that the new theory is reliable and feasible. The economic benefit can be obtained from the engineering application of the new theory.

  9. Stability analysis of axisymmetric supersonic wakes using various basic states

    International Nuclear Information System (INIS)

    Two-dimensional stability analyses are conducted of turbulent axisymmetric supersonic wakes at M = 2.46. The aim is to investigate which azimuthal modes are dominant and how the stability behaviour is influenced by the choice of basic state. To that end, axisymmetric (two dimensional) and three dimensional direct numerical simulations (DNS) with either laminar or turbulent inflow conditions were conducted of supersonic wakes to provide the respective basic states for the stability analysis. The global stability analyses were then performed by computing the temporal pulse response using forced Navier-Stokes simulations for each basic state. Using the time- and azimuthally-averaged data from the 3D DNS with turbulent inflow as basic state, an absolute instability of the axisymmetric mode at a Reynolds number, based on wake-generating body diameter and freestream velocity, ReD = 100,000 was found. This is in contrast to results obtained earlier using an axisymmetric flow solution as the basic state. The linear stability analysis for all basic states is presented showing the temporal growth of various azimuthal modes and the respective radial mode shapes. The results are also contrasted to those obtained from nonlinear DNS.

  10. Stability of a compound sessile drop at the axisymmetric configuration.

    Science.gov (United States)

    Zhang, Ying; Chatain, Dominique; Anna, Shelley L; Garoff, Stephen

    2016-01-15

    The equilibrium configuration of compound sessile drops has been calculated previously in the absence of gravity. Using the Laplace equations, we establish seven dimensionless parameters describing the axisymmetric configuration in the presence of gravity. The equilibrium axisymmetric configuration can be either stable or unstable depending on the fluid properties. A stability criterion is established by calculating forces on a perturbed Laplacian shape. In the zero Bond number limit, the stability criterion depends on the density ratio, two ratios of interfacial tensions, the volume ratio of the two drops, and the contact angle. We use Surface Evolver to examine the stability of compound sessile drops at small and large Bond numbers and compare with the zero Bond number approximation. Experimentally, we realize a stable axisymmetric compound sessile drop in air, where the buoyancy force exerted by the air is negligible. Finally, using a pair of fluids in which the density ratio can be tuned nearly independently of the interfacial tensions, the stability transition is verified for the axisymmetric configuration. Even though the perturbations are different for the theory, simulations and experiments, both simulations and experiments agree closely with the zero Bond number approximation, exhibiting a small discrepancy at large Bond number. PMID:26433481

  11. ON INTEGRITY ASSESSMENT OF AXISYMMETRIC COMPONENTS OPERATING WITHIN CREEP REGIME

    Institute of Scientific and Technical Information of China (English)

    ZARRABI K; LAWRENCE Ng

    2006-01-01

    A multiaxial paradigm for predicting creep damage/lives of components is described. Although in principle the paradigm is general, it is verified using axisymmetric experimental data. It is shown that the proposed paradigm is capable of predicting creep lives with an error of less than 2%. It is also shown that the proposed paradigm is more accurate than the reference stress method.

  12. Hawking radiation via tunnelling from general stationary axisymmetric black holes

    Institute of Scientific and Technical Information of China (English)

    Zhang Jing-Yi; Fan Jun-Hui

    2007-01-01

    Hawking radiation is viewed as a tunnelling process. In this way the emission rates of massless particles and massive particles tunnelling across the event horizon of general stationary axisymmetric black holes are calculated,separately. The emission spectra of these two different kinds of outgoing particles have the same functional form and both are consistent with an underlying unitary theory.

  13. Motion of charged particle in axisymmetric electromagnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Robouch, B.V. [ENEA, Frascati (Italy). Dipartimento Energia; Gratreau, P.

    1995-05-01

    A previous work is now extended to cover toroidal or corrugated (periodically perturbed) axisymmetric fields. Coordinate surfaces are defined as being coincident with the magnetic surfaces. Scale factors are determined. Equations of motion are obtained in their exact form. This allows a direct numerical treatment instead of having to resort to iterative methods of successive approximations.

  14. Modelling Acoustic Wave Propagation in Axisymmetric Varying-Radius Waveguides

    DEFF Research Database (Denmark)

    Bæk, David; Willatzen, Morten

    2008-01-01

    A computationally fast and accurate model (a set of coupled ordinary differential equations) for fluid sound-wave propagation in infinite axisymmetric waveguides of varying radius is proposed. The model accounts for fluid heat conduction and fluid irrotational viscosity. The model problem is solv...

  15. Non-axisymmetric flow characteristics in centrifugal compressor

    Science.gov (United States)

    Wang, Leilei; Lao, Dazhong; Liu, Yixiong; Yang, Ce

    2015-06-01

    The flow field distribution in centrifugal compressor is significantly affected by the non-axisymmetric geometry structure of the volute. The experimental and numerical simulation methods were adopted in this work to study the compressor flow field distribution with different flow conditions. The results show that the pressure distributionin volute is characterized by the circumferential non-uniform phenomenon and the pressure fluctuation on the high static pressure zone propagates reversely to upstream, which results in the non-axisymmetric flow inside the compressor. The non-uniform level of pressure distribution in large flow condition is higher than that in small flow condition, its effect on the upstream flow field is also stronger. Additionally, the non-uniform circumferential pressure distribution in volute brings the non-axisymmetric flow at impeller outlet. In different flow conditions,the circumferential variation of the absolute flow angle at impeller outlet is also different. Meanwhile, the non-axisymmetric flow characteristics in internal impeller can be also reflected by the distribution of the mass flow. The high static pressure region of the volute corresponds to the decrease of mass flow in upstream blade channel, while the low static pressure zone of the volute corresponds to the increase of the mass flow. In small flow condition, the mass flow difference in the blade channel is bigger than that in the large flow condition.

  16. Plane SPDC-Quantum Mirror

    CERN Document Server

    Ion, M L D

    2013-01-01

    In this paper the kinematical correlations from the phase conjugated optics (equivalently with crossing symmetric spontaneous parametric down conversion (SPDC) phenomena) in the nonlinear crystals are used for the description of a new kind of optical device called SPDC-quantum mirrors. Then, some important laws of the plane SPDC-quantum mirrors combined with usual mirrors or lens are proved only by using geometric optics concepts. In particular, these results allow us to obtain a new interpretation of the recent experiments on the two-photon geometric optics.

  17. JWST NIRCam flight mirror assemblies

    Science.gov (United States)

    Mammini, Paul V.; Holmes, Howard C.; Huff, Lynn; Jacoby, Mike S.; Lopez, Frank

    2011-10-01

    The Near Infrared Camera (NIRCam) instrument for NASA's James Webb Space Telescope (JWST) has an optical prescription which includes numerous fold mirror assemblies. The instrument will operate at 35K after experiencing launch loads at ~293K. The optic mounts must accommodate all associated thermal and mechanical stresses, plus maintain exceptional optical quality during operation. Lockheed Martin Space Systems Company (LMSSC) conceived, designed, analyzed, assembled, tested, and integrated the mirror assemblies for the NIRCam instrument. This paper covers the design, analysis, assembly, and test of two of the instruments key fold mirrors.

  18. Polarimetry with multiple mirror telescopes

    Science.gov (United States)

    West, S. C.

    1986-01-01

    The polarizations of multiple mirror telescopes are calculated using Mueller calculus. It is found that the Multiple Mirror Telescope (MMT) produces a constant depolarization that is a function of wavelength and independent of sky position. The efficiency and crosstalk are modeled and experimentally verified. The two- and four-mirror new generation telescopes are found to produce sinusoidal depolarization for which an accurate interpretation of the incident Stokes vector requires inverse matrix calculations. Finally, the depolarization of f/1 paraboloids is calculated and found to be less than 0.1 percent at 3000 A.

  19. Evanescent Wave Atomic Mirror

    Science.gov (United States)

    Ghezali, S.; Taleb, A.

    2008-09-01

    A research project at the "Laboratoire d'électronique quantique" consists in a theoretical study of the reflection and diffraction phenomena via an atomic mirror. This poster presents the principle of an atomic mirror. Many groups in the world have constructed this type of atom optics experiments such as in Paris-Orsay-Villetaneuse (France), Stanford-Gaithersburg (USA), Munich-Heidelberg (Germany), etc. A laser beam goes into a prism with an incidence bigger than the critical incidence. It undergoes a total reflection on the plane face of the prism and then exits. The transmitted resulting wave out of the prism is evanescent and repulsive as the frequency detuning of the laser beam compared to the atomic transition δ = ωL-ω0 is positive. The cold atomic sample interacts with this evanescent wave and undergoes one or more elastic bounces by passing into backward points in its trajectory because the atoms' kinetic energy (of the order of the μeV) is less than the maximum of the dipolar potential barrier ℏΩ2/Δ where Ω is the Rabi frequency [1]. In fact, the atoms are cooled and captured in a magneto-optical trap placed at a distance of the order of the cm above the prism surface. The dipolar potential with which interact the slow atoms is obtained for a two level atom in a case of a dipolar electric transition (D2 Rubidium transition at a wavelength of 780nm delivered by a Titane-Saphir laser between a fundamental state Jf = l/2 and an excited state Je = 3/2). This potential is corrected by an attractive Van der Waals term which varies as 1/z3 in the Lennard-Jones approximation (typical atomic distance of the order of λ0/2π where λ0 is the laser wavelength) and in 1/z4 if the distance between the atom and its image in the dielectric is big in front of λ0/2π. This last case is obtained in a quantum electrodynamic calculation by taking into account an orthornormal base [2]. We'll examine the role of spontaneous emission for which the rate is inversely

  20. Edificio Daily Mirror

    Directory of Open Access Journals (Sweden)

    Williams, Owen

    1963-07-01

    Full Text Available The building has 18 levels. The Press occupies the 4 basement floors. The ground floor is taken up with the entrance hall, and an indoor carriage way. A snack bar and the telephone operators are situated on the second floor. The production department and the medical services are located on the third storey, whilst the fourth is occupied by the offices and library. The fifth floor is the beginning of the higher section of the building. This floor and up to including the 11th floor are devoted to office space, except for the 10th storey, which contains the office apartments of the directors and the Council Chamber. Equipment related to various services of the building is housed on the 12th storey. Finally, this tall building constitutes a fine landmark in the London skyline. The Daily Mirror building is outstanding for the appropriate nature, the completeness and the quality of its installations, which thus provide the most widely read paper in the world with outstandingly efficient offices.Este edificio consta de 18 plantas. El cuerpo de Prensa se aloja en los cuatro sótanos; los vestíbulos de entrada y una calzada interior para vehículos se hallan en la planta baja; la primera alberga un snack-bar y centralita telefónica; la segunda, el departamento de producción y centro de asistencia médica, y la tercera, las oficinas y biblioteca principales. La cuarta planta señala el comienzo del bloque alto; esta planta, junto con las quinta, sexta, séptima, octava y décima, están dedicadas a oficinas. La novena contiene las oficinas-apartamentos de los directores y salas de Consejo, y la undécima, la maquinaria para las diversas instalaciones del edificio. La elevada torre constituye un grandioso hito de referencia en esta zona de Londres. El «Daily Mirror» se distingue por el acierto, número y perfección de sus instalaciones, que proporcionan, al periódico de mayor actualidad mundial, las más adecuadas y amplias oficinas modernas.

  1. Transient axial solution for plane and axisymmetric waves focused by a paraboloidal reflector.

    Science.gov (United States)

    Tsai, Yi-Te; Zhu, Jinying; Haberman, Michael R

    2013-04-01

    A time domain analytical solution is presented to calculate the pressure response along the axis of a paraboloidal reflector for a normally incident plane wave. This work is inspired by Hamilton's axial solution for an ellipsoidal mirror and the same methodology is employed in this paper. Behavior of the reflected waves along reflector axis is studied, and special interest is placed on focusing gain obtained at the focal point. This analytical solution indicates that the focusing gain is affected by reflector geometry and the time derivative of the input signal. In addition, focused pressure response in the focal zone given by various reflector geometries and input frequencies are also investigated. This information is useful for selecting appropriate reflector geometry in a specific working environment to achieve the best signal enhancement. Numerical simulation employing the finite element method is used to validate the analytical solution, and visualize the wave field to provide a better understanding of the propagation of reflected waves. This analytical solution can be modified to apply to non-planar incident waves with axisymmetric wavefront and non-uniform pressure distribution. An example of incident waves with conical-shaped wavefront is presented. PMID:23556573

  2. Responder fast steering mirror

    Science.gov (United States)

    Bullard, Andrew; Shawki, Islam

    2013-10-01

    Raytheon Space and Airborne Systems (SAS) has designed, built and tested a 3.3-inch diameter fast steering mirror (FSM) for space application. This 2-axis FSM operates over a large angle (over 10 degree range), has a very high servo bandwidth (over 3.3 Khz closed loop bandwidth), has nanoradian-class noise, and is designed to support microradian class line of sight accuracy. The FSM maintains excellent performance over large temperature ranges (which includes wave front error) and has very high reliability with the help of fully redundant angle sensors and actuator circuits. The FSM is capable of achieving all its design requirements while also being reaction-compensated. The reaction compensation is achieved passively and does not need a separate control loop. The FSM has undergone various environmental testing which include exported forces and torques and thermal vacuum testing that support the FSM design claims. This paper presents the mechanical design and test results of the mechanism which satisfies the rigorous vacuum and space application requirements.

  3. Tandem Terminal Ion Source

    International Nuclear Information System (INIS)

    OAK-B135 Tandem Terminal Ion Source. The terminal ion source (TIS) was used in several experiments during this reporting period, all for the(sup 7)Be((gamma))(sup 8)B experiment. Most of the runs used(sup 1)H(sup+) at terminal voltages from 0.3 MV to 1.5 MV. One of the runs used(sup 2)H(sup+) at terminal voltage of 1.4 MV. The other run used(sup 4)He(sup+) at a terminal voltage of 1.37 MV. The list of experiments run with the TIS to date is given in table 1 below. The tank was opened four times for unscheduled source repairs. On one occasion the tank was opened to replace the einzel lens power supply which had failed. The 10 kV unit was replaced with a 15 kV unit. The second time the tank was opened to repair the extractor supply which was damaged by a tank spark. On the next occasion the tank was opened to replace a source canal which had sputtered away. Finally, the tank was opened to replace the discharge bottle which had been coated with aluminum sputtered from the exit canal

  4. Tandem Terminal Ion Source

    International Nuclear Information System (INIS)

    OAK-B135 Tandem Terminal Ion Source. The terminal ion source (TIS) was used in several experiments during this reporting period, all for the 7Be(γ)8B experiment. Most of the runs used 1H+ at terminal voltages from 0.3 MV to 1.5 MV. One of the runs used 2H+ at terminal voltage of 1.4 MV. The other run used 4He+ at a terminal voltage of 1.37 MV. The list of experiments run with the TIS to date is given in table 1 below. The tank was opened four times for unscheduled source repairs. On one occasion the tank was opened to replace the einzel lens power supply which had failed. The 10 kV unit was replaced with a 15 kV unit. The second time the tank was opened to repair the extractor supply which was damaged by a tank spark. On the next occasion the tank was opened to replace a source canal which had sputtered away. Finally, the tank was opened to replace the discharge bottle which had been coated with aluminum sputtered from the exit canal

  5. Reflections on a Black Mirror

    CERN Document Server

    Good, Michael R R

    2016-01-01

    A black mirror is an accelerated boundary that produces particles in an exact correspondence to an evaporating black hole. We investigate the spectral dynamics of the particle creation during the formation process.

  6. Dielectric Coatings for IACT Mirrors

    CERN Document Server

    Förster, A; Chadwick, P; Held, M

    2013-01-01

    Imaging Atmospheric Cherenkov Telescopes for very-high energy gamma-ray astronomy need mirror with high reflectance roughly in the wavelength between 300 and 550 nm. The current standard reflective layer of such mirrors is aluminum. Being permanently exposed to the environment they show a constant degradation over the years. New and improved dielectric coatings have been developed to enhance their resistance to environmental impact and to extend their possible lifetime. In addition, these customized coatings have an increased reflectance of over 95% and are designed to significantly lower the night-sky background contribution. The development of such coatings for mirrors with areas up to 2 m2 and low application temperatures to suite the composite materials used for the new mirror susbtrates of the Cherenkov Telescope Array (CTA) and the results of extensive durability tests are presented.

  7. Advanced Mirror Material System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Peregrine will bring together recent laboratory developments and mature the technology so that complete mirror and telescope assemblies can be reliably and robustly...

  8. Fast Picometer Mirror Mount Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is a 6DOF controllable mirror mount with high dynamic range and fast tip/tilt capability for space based applications. It will enable the...

  9. FAME: Freeform Active Mirrors Experiment

    Science.gov (United States)

    Hugot, Emmanuel; Agocs, Tibor; Challita, Zalpha; Jasko, Attila; Kroes, Gabby; Banyai, Evelin; Miller, Chris; Taylor, William; Schnetler, Hermine; Venema, Lars

    2014-07-01

    This paper discusses the development of a demonstrator freeform active mirror for future astronomical instruments both on Earth and in space. It consists of a system overview and progress in various areas of technology in the building blocks of the mirror: an extreme freeform thin face sheet, an active array, design tools and the metrology and control of the system. The demonstrator aims to investigate the applicability of the technique in high end astronomical systems, also for space and cryogenically.

  10. Large Scale Nanolaminate Deformable Mirror

    Energy Technology Data Exchange (ETDEWEB)

    Papavasiliou, A; Olivier, S; Barbee, T; Miles, R; Chang, K

    2005-11-30

    This work concerns the development of a technology that uses Nanolaminate foils to form light-weight, deformable mirrors that are scalable over a wide range of mirror sizes. While MEMS-based deformable mirrors and spatial light modulators have considerably reduced the cost and increased the capabilities of adaptive optic systems, there has not been a way to utilize the advantages of lithography and batch-fabrication to produce large-scale deformable mirrors. This technology is made scalable by using fabrication techniques and lithography that are not limited to the sizes of conventional MEMS devices. Like many MEMS devices, these mirrors use parallel plate electrostatic actuators. This technology replicates that functionality by suspending a horizontal piece of nanolaminate foil over an electrode by electroplated nickel posts. This actuator is attached, with another post, to another nanolaminate foil that acts as the mirror surface. Most MEMS devices are produced with integrated circuit lithography techniques that are capable of very small line widths, but are not scalable to large sizes. This technology is very tolerant of lithography errors and can use coarser, printed circuit board lithography techniques that can be scaled to very large sizes. These mirrors use small, lithographically defined actuators and thin nanolaminate foils allowing them to produce deformations over a large area while minimizing weight. This paper will describe a staged program to develop this technology. First-principles models were developed to determine design parameters. Three stages of fabrication will be described starting with a 3 x 3 device using conventional metal foils and epoxy to a 10-across all-metal device with nanolaminate mirror surfaces.

  11. The Casimir force for passive mirrors

    OpenAIRE

    Lambrecht, A.; Jaekel, M. -T.; Reynaud, S.

    1998-01-01

    We show that the Casimir force between mirrors with arbitrary frequency dependent reflectivities obeys bounds due to causality and passivity properties. The force is always smaller than the Casimir force between two perfectly reflecting mirrors. For narrow-band mirrors in particular, the force is found to decrease with the mirrors bandwidth.

  12. Some Reflections on Plane Mirrors and Images.

    Science.gov (United States)

    Galili, Igal; And Others

    1991-01-01

    Discusses the following questions based on the assumption that students' personal experiences and prior beliefs about plane mirrors can promote interesting discussions: (1) How mirror images are formed? (2) Why doesn't paper behave like a mirror? (3) Does a mirror left-right reverse objects? and (4) Why are corner images of two perpendicular…

  13. Tandem Cylinder Noise Predictions

    Science.gov (United States)

    Lockhard, David P.; Khorrami, Mehdi R.; CHoudhari, Meelan M.; Hutcheson, Florence V.; Brooks, Thomas F.; Stead, Daniel J.

    2007-01-01

    In an effort to better understand landing-gear noise sources, we have been examining a simplified configuration that still maintains some of the salient features of landing-gear flow fields. In particular, tandem cylinders have been studied because they model a variety of component level interactions. The present effort is directed at the case of two identical cylinders spatially separated in the streamwise direction by 3.7 diameters. Experimental measurements from the Basic Aerodynamic Research Tunnel (BART) and Quiet Flow Facility (QFF) at NASA Langley Research Center (LaRC) have provided steady surface pressures, detailed off-surface measurements of the flow field using Particle Image Velocimetry (PIV), hot-wire measurements in the wake of the rear cylinder, unsteady surface pressure data, and the radiated noise. The experiments were conducted at a Reynolds number of 166 105 based on the cylinder diameter. A trip was used on the upstream cylinder to insure a fully turbulent shedding process and simulate the effects of a high Reynolds number flow. The parallel computational effort uses the three-dimensional Navier-Stokes solver CFL3D with a hybrid, zonal turbulence model that turns off the turbulence production term everywhere except in a narrow ring surrounding solid surfaces. The current calculations further explore the influence of the grid resolution and spanwise extent on the flow and associated radiated noise. Extensive comparisons with the experimental data are used to assess the ability of the computations to simulate the details of the flow. The results show that the pressure fluctuations on the upstream cylinder, caused by vortex shedding, are smaller than those generated on the downstream cylinder by wake interaction. Consequently, the downstream cylinder dominates the noise radiation, producing an overall directivity pattern that is similar to that of an isolated cylinder. Only calculations based on the full length of the model span were able to

  14. Application of the PTT model to axisymmetric free surface flows

    Science.gov (United States)

    Merejolli, R.; Paulo, G. S.; Tomé, M. F.

    2013-10-01

    This work is concerned with numerical simulation of axisymmetric viscoelastic free surface flows using the Phan-Thien-Tanner (PTT) constitutive equation. A finite difference technique for solving the governing equations for unsteady incompressible flows written in Cylindrical coordinates on a staggered grid is described. The fluid is modelled by a Marker-and-Cell type method and an accurate representation of the fluid surface is employed. The full free surface stress conditions are applied. The numerical method is verified by comparing numerical predictions of fully developed flow in a pipe with the corresponding analytic solutions. To demonstrate that the numerical method can simulate axisymmetric free surface flows governed by the PTT model, numerical results of the flow evolution of a drop impacting on a rigid dry plate are presented. In these simulations, the rheological effects of the parameters ɛ and ξ are investigated.

  15. Modeling the Orion nebula as an axisymmetric blister

    Science.gov (United States)

    Rubin, R. H.; Simpson, J. P.; Haas, M. R.; Erickson, E. F.

    1991-01-01

    The ionized gas in the Orion nebula is examined by means of axisymmetric modeling that is based on observational data from the ionized, neutral, and molecular regions. Nonsymmetrical features are omitted, radial dependence from the Trapezium is assumed, and azimuthal symmetry in the plane of the sky is used. Stellar properties and abundances of certain elements are described, and these data are used to compare the present axisymmetric-blister model to a previous spherical model. Strong singly-ionized emission that are visible near the Trapezium are found to originate in the ionization-bounded region in the dense Trapezium zone. The model can be more tightly constrained by adding near-IR data on noncentral zones for (Ar II), (AR III), (Ne II), and (S IV). The quadrant with the 'bar' creates an nonsymmetry that influences the observational data, and the model can therefore be improved with the additional data.

  16. Axisymmetric large eddy simulation of a circular source of buoyancy

    Energy Technology Data Exchange (ETDEWEB)

    Nihous, Gerard C., E-mail: nihous@hawaii.ed [University of Hawaii, Hawaii Natural Energy Institute, 1680 East-West Road, POST 109, Honolulu, HI 96822 (United States)

    2009-12-15

    Axisymmetric large-eddy simulations (LES) of published experiments on vertical mixing above a circular source of buoyancy are performed. Numerical results confirm the existence of a mixing boundary layer just above the buoyancy source (freshwater injected into saline water). As experiments suggested, the calculated normalized shape of the boundary layer seems independent of source size, freshwater injection rate and background solute concentration. This validates a restrictive but numerically efficient assumption of axisymmetric turbulence for the LES calculations. It also lends additional credibility to the theoretical boundary-layer analysis of Epstein and Burelbach [Epstein, M., Burelbach, J.P., 2001. Vertical mixing above a steady circular source of buoyancy. Int. J. Heat Mass Trans. 44, 525-536], even at marginally high Froude numbers.

  17. Axisymmetric large eddy simulation of a circular source of buoyancy

    International Nuclear Information System (INIS)

    Axisymmetric large-eddy simulations (LES) of published experiments on vertical mixing above a circular source of buoyancy are performed. Numerical results confirm the existence of a mixing boundary layer just above the buoyancy source (freshwater injected into saline water). As experiments suggested, the calculated normalized shape of the boundary layer seems independent of source size, freshwater injection rate and background solute concentration. This validates a restrictive but numerically efficient assumption of axisymmetric turbulence for the LES calculations. It also lends additional credibility to the theoretical boundary-layer analysis of Epstein and Burelbach [Epstein, M., Burelbach, J.P., 2001. Vertical mixing above a steady circular source of buoyancy. Int. J. Heat Mass Trans. 44, 525-536], even at marginally high Froude numbers.

  18. AXISYMMETRIC FLOW THROUGH A PERMEABLE NEAR-SPHERE

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    An analytical approach is described for the axisymmetric flow through a permeable near-sphere with a modification to boundary conditions in order to account permeability. The Stokes equation was solved by a regular perturbation technique up to the second order correction in epsilon representing the deviation from the radius of nondeformed sphere. The drag and the flow rate were calculated and the results were evaluated from the point of geometry and the permeability of the surface. An attempt also was made to apply the theory to the filter feeding problem. The filter appendages of small ecologically important aquatic organisms were modeled as axisymmetric permeable bodies, therefore a rough model for this problem was considered here as an oblate spheroid or near-sphere.

  19. Stable photon orbits in stationary axisymmetric electrovacuum spacetimes

    CERN Document Server

    Dolan, Sam R

    2016-01-01

    We investigate the existence and phenomenology of stable photon orbits (SPOs) in stationary axisymmetric electrovacuum spacetimes in four dimensions. First, we classify the equatorial circular photon orbits of Kerr-Newman spacetimes in the charge-spin plane. Second, using a Hamiltonian formulation, we show that Reissner-Nordstr\\"om di-holes (a family encompassing the Majumdar-Papapetrou and Weyl-Bach special cases) admit SPOs, in a certain parameter regime that we investigate. Third, we explore the transition from order to chaos for typical SPOs bounded within a torus around a di-hole, via a selection of Poincar\\'e sections. Finally, for general axisymmetric stationary spacetimes, we show that the Einstein-Maxwell field equations allow for the existence of SPOs in electrovacuum; but not in pure vacuum.

  20. Dynamics and thermodynamics of axisymmetric flows: I. Theory

    CERN Document Server

    Leprovost, N; Chavanis, P H; Leprovost, Nicolas; Chavanis, Pierre-Henri

    2005-01-01

    We develop new variational principles to study stability and equilibrium of axisymmetric flows. We show that there is an infinite number of steady state solutions. We show that these steady states maximize a (non-universal) $H$-function. We derive relaxation equations which can be used as numerical algorithm to construct stable stationary solutions of axisymmetric flows. In a second part, we develop a thermodynamical approach to the equilibrium states at some fixed coarse-grained scale. We show that the resulting distribution can be divided in a universal part coming from the conservation of robust invariants and one non-universal determined by the initial conditions through the fragile invariants (for freely evolving systems) or by a prior distribution encoding non-ideal effects such as viscosity, small-scale forcing and dissipation (for forced systems). Finally, we derive a parameterization of inviscid mixing to describe the dynamics of the system at the coarse-grained scale.

  1. Numerical observation of non-axisymmetric vesicles in fluid membranes

    CERN Document Server

    Jie, Y; Ji Xing Liu; Zhong Can Ou Yang; Jie, Yan; Quan-Hui, Liu; Ji-Xing, Liu; Zhong-Can, Ou-Yang

    1998-01-01

    By means of Surface Evolver (Exp. Math,1,141 1992), a software package of brute-force energy minimization over a triangulated surface developed by the geometry center of University of Minnesota, we have numerically searched the non-axisymmetric shapes under the Helfrich spontaneous curvature (SC) energy model. We show for the first time there are abundant mechanically stable non-axisymmetric vesicles in SC model, including regular ones with intrinsic geometric symmetry and complex irregular ones. We report in this paper several interesting shapes including a corniculate shape with six corns, a quadri-concave shape, a shape resembling sickle cells, and a shape resembling acanthocytes. As far as we know, these shapes have not been theoretically obtained by any curvature model before. In addition, the role of the spontaneous curvature in the formation of irregular crenated vesicles has been studied. The results shows a positive spontaneous curvature may be a necessary condition to keep an irregular crenated shap...

  2. Axisymmetric solitary waves on the surface of a ferrofluid

    OpenAIRE

    Bourdin, Elise; Bacri, Jean-Claude; Falcon, Eric

    2010-01-01

    We report the first observation of axisymmetric solitary waves on the surface of a cylindrical magnetic fluid layer surrounding a current-carrying metallic tube. According to the ratio between the magnetic and capillary forces, both elevation and depression solitary waves are observed with profiles in good agreement with theoretical predictions based on the magnetic analogue of the Korteweg-deVries equation. We also report the first measurements of the velocity and the dispersion relation of ...

  3. Stationary and Axisymmetric Perfect-Fluid Solutions with Conformal Motion

    OpenAIRE

    Mars, Marc; Senovilla, Jose M M

    2002-01-01

    Stationary and axisymmetric perfect-fluid metrics are studied under the assumption of the existence of a conformal Killing vector field and in the general case of differential rotation. The possible Lie algebras for the conformal group and corresponding canonical line-elements are explicitly given. It turns out that only four different cases appear, the abelian and other three called I, II and III. We explicitly find all the solutions in the abelian and I cases. For the abelian case the gener...

  4. Axisymmetric smoothed particle hydrodynamics with self-gravity

    OpenAIRE

    García Senz, Domingo; Relano, A.; Cabezón Gómez, Rubén Martín; Bravo Guil, Eduardo

    2008-01-01

    The axisymmetric form of the hydrodynamic equations within the smoothed particle hydrodynamics (SPH) formalism is presented and checked using idealized scenarios taken from astrophysics (free fall collapse, implosion and further pulsation of a Sun-like star), gas dynamics (wall heating problem, collision of two streams of gas) and inertial confinement fusion (ablative implosion of a small capsule). New material concerning the standard SPH formalism is given. That includes the numerical handli...

  5. Axisymmetric and triaxial MOND density-potential pairs

    OpenAIRE

    Ciotti, L.; Londrillo, P.; Nipoti, C.

    2005-01-01

    We present a simple method, based on the deformation of spherically symmetric potentials, to construct explicit axisymmetric and triaxial MOND density-potential pairs. General guidelines to the choice of suitable deformations, so that the resulting density distribution is nowhere negative, are presented. This flexible method offers for the first time the possibility to study the MOND gravitational field for sufficiently general and realistic density distributions without resorting to sophisti...

  6. Modelling axisymmetric cod-ends made of different mesh types

    DEFF Research Database (Denmark)

    Priour, D.; Herrmann, Bent; O'Neill, F.G.

    2009-01-01

    Cod-ends are the rearmost part of trawl fishing gears. They collect the catch, and for many important species it is where fish selection takes place. Generally speaking they are axisymmetric, and their shape is influenced by the catch volume, the mesh shape, and the material characteristics. The ...... of the netting. The software package developed to solve this problem is freely available. Comparisons are carried out with a previous model and experimental data....

  7. Non-axisymmetric oscillations of differentially rotating relativistic stars

    OpenAIRE

    Passamonti, Andrea; Stavridis, Adamantios; Kokkotas, Kostas

    2007-01-01

    Non-axisymmetric oscillations of differentially rotating stars are studied using both slow rotation and Cowling approximation. The equilibrium stellar models are relativistic polytropes where differential rotation is described by the relativistic j-constant rotation law. The oscillation spectrum is studied versus three main parameters: the stellar compactness $M/R$, the degree of differential rotation $A$ and the number of maximun couplings $\\ell_{\\rm max}$. It is shown that the rotational sp...

  8. Study on the Interaction of Non-axisymmetric Binary Vortices

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In the context of advection dynamics, 19 experiments (Exps.) are performed using a quasi-geostrophic barotropic vorticity equation model to explore the condition for the mergence of binary vortices and the self-organization of the larger scale vortex. Results show that the initial distance between the centers of binary vortices and the non-axisymmetric distributions of their initial vorticity are two factors affecting the mergence of binary vortices. There is a critical distance for the mergence of initial symmetric binary vortices, however, the mergence of initial non-axisymmetric binary vortices is also affected by the asymmetric structure of initial vortices. The self-organization processes in 19 experiments can be classified into two types: one is the merging of identical, axisymmetric binary vortices in which the interaction of the two vortices undergoes slowly change, rapid change, and the formation, stretching, and development of the filaments of vorticity, and the two vortices merge into a symmetric vortex, with its vorticity piled up in the inner region coming from the two initial vortices, and the vorticity of the spiral band in the outer region from the stretching of the filaments of the two initial vortices. And the other type is the merging of the two non-axisymmetric initial vortices of an elliptic vortex and an eccentric vortex hi which the elliptic vortex, on the one hand, mutually rotates, and on the other hand moves towards the center of the computational domain, at the same time expands its vorticity area, and at last forms the inner core of resultant state vortex; and the eccentric vortex mutually rotates, meanwhile continuously stretches, and finally forms the spiral band of resultant state vortex. The interaction process is characteristic of the vorticity piled up in the inner core region of resultant state vortex originating from the elliptic vortex and the vorticity in spiral band mainly from the successive stretch and rupture of the

  9. Resonant Absorption of Axisymmetric Modes in Twisted Magnetic Flux Tubes

    Science.gov (United States)

    Giagkiozis, I.; Goossens, M.; Verth, G.; Fedun, V.; Van Doorsselaere, T.

    2016-06-01

    It has been shown recently that magnetic twist and axisymmetric MHD modes are ubiquitous in the solar atmosphere, and therefore the study of resonant absorption for these modes has become a pressing issue because it can have important consequences for heating magnetic flux tubes in the solar atmosphere and the observed damping. In this investigation, for the first time, we calculate the damping rate for axisymmetric MHD waves in weakly twisted magnetic flux tubes. Our aim is to investigate the impact of resonant damping of these modes for solar atmospheric conditions. This analytical study is based on an idealized configuration of a straight magnetic flux tube with a weak magnetic twist inside as well as outside the tube. By implementing the conservation laws derived by Sakurai et al. and the analytic solutions for weakly twisted flux tubes obtained recently by Giagkiozis et al. we derive a dispersion relation for resonantly damped axisymmetric modes in the spectrum of the Alfvén continuum. We also obtain an insightful analytical expression for the damping rate in the long wavelength limit. Furthermore, it is shown that both the longitudinal magnetic field and the density, which are allowed to vary continuously in the inhomogeneous layer, have a significant impact on the damping time. Given the conditions in the solar atmosphere, resonantly damped axisymmetric modes are highly likely to be ubiquitous and play an important role in energy dissipation. We also suggest that, given the character of these waves, it is likely that they have already been observed in the guise of Alfvén waves.

  10. Dynamical system properties of an axisymmetric convective tropical cyclone model

    OpenAIRE

    Schönemann, Daria; Frisius, Thomas

    2014-01-01

    The dynamical system behaviour of tropical cyclones and their potential intensity with a view to sea surface temperature, tropospheric temperature stratification and tropospheric moisture content is investigated in the axisymmetric convective model HURMOD. The model results exhibit the existence of a fixed-point attractor associated with a strong tropical cyclone. Moreover, the initial vortex strength forms an amplitude threshold to cyclogenesis. Above this threshold, the size of the tropical...

  11. AXISYMMETRIC MHD INSTABILITIES IN SOLAR/STELLAR TACHOCLINES

    International Nuclear Information System (INIS)

    Extensive studies over the past decade showed that HD and MHD nonaxisymmetric instabilities exist in the solar tachocline for a wide range of toroidal field profiles, amplitudes, and latitude locations. Axisymmetric instabilities (m = 0) do not exist in two dimensions, and are excited in quasi-three-dimensional shallow-water systems only for very high field strengths (2 mG). We investigate here MHD axisymmetric instabilities in a three-dimensional thin-shell model of the solar/stellar tachocline, employing a hydrostatic, non-Boussinesq system of equations. We deduce a number of general properties of the instability by use of an integral theorem, as well as finding detailed numerical solutions for unstable modes. Toroidal bands become unstable to axisymmetric perturbations for solar-like field strengths (100 kG). The e-folding time can be months down to a few hours if the field strength is 1 mG or higher, which might occur in the solar core, white dwarfs, or neutron stars. These instabilities exist without rotation, with rotation, and with differential rotation, although both rotation and differential rotation have stabilizing effects. Broad toroidal fields are stable. The instability for modes with m = 0 is driven from the poleward shoulder of banded profiles by a perturbation magnetic curvature stress that overcomes the stabilizing Coriolis force. The nonaxisymmetric instability tips or deforms a band; with axisymmetric instability, the fluid can roll in latitude and radius, and can convert bands into tubes stacked in radius. The velocity produced by this instability in the case of low-latitude bands crosses the equator, and hence can provide a mechanism for interhemispheric coupling.

  12. Viscosity Effects on the Dynamics of Long Axisymmetric Liquid Bridges

    OpenAIRE

    Meseguer Ruiz, José; Perales Perales, José Manuel

    1992-01-01

    In this paper the dynamics of axisymmetric liquid columns held by capillary forces between two circular, concentric, solid disks is considered. The problem has been solved by using an one-dimensional model known in the literature as the Cosserat model, which includes viscosity effects, where the axial velocity is considered constant in each section of the liquid bridge. The dynamic response of the bridge to an excitation consisting of a small amplitude vibration of the supporting disks has be...

  13. Stability of perturbed geodesics in $nD$ axisymmetric spacetimes

    CERN Document Server

    Coimbra-Araujo, C H

    2016-01-01

    The effect of self-gravity of a disk matter is evaluated by the simplest modes of oscillation frequencies for perturbed circular geodesics. It is plotted the radial profiles of free oscillations of an equatorial circular geodesic perturbed within the orbital plane or in the vertical direction. The calculation is carried out to geodesics of an axisymmetric $n$-dimensional spacetime. The profiles are computed by examples of disks embeded in five-dimensional or six-dimensional spacetime, where it is studied the motion of free test particles for three axisymmetric cases: (i) the Newtonian limit of a general proposed $5D$ and $6D$ axisymmetric spacetime; (ii) a simple Randall-Sundrum $5D$ spacetime; (iii) general $5D$ and $6D$ Randall-Sundrum spacetime. The equation of motion of such particles is derived and the stability study is computed for both horizontal and vertical directions, to see how extra dimensions could affect the system. In particular, we investigate a disk constructed from Schwarzschild and Chazy-C...

  14. Position sensors for segmented mirror

    Science.gov (United States)

    Rozière, Didier; Buous, Sébastien; Courteville, Alain

    2004-09-01

    There are currently several projects for giant telescopes with segmented mirrors under way. These future telescopes will have their primary mirror made of several thousand segments. The main advantage of segmentation is that it enables the active control of the whole mirror, so as to suppress the deformations of the support structure due to the wind, gravity, thermal inhomogeneities etc. ..., thus getting the best possible stigmatism. However, providing active control of segmented mirrors requires numerous accurate edges sensors. It is acknowledged that capacitance-based technology nowadays offers the best metrological performances-to-cost ratio. As the leader in capacitive technology, FOGALE nanotech offers an original concept which reduces the cost of instrumentation, sensors and electronics, while keeping a very high level of performances with a manufacturing process completely industrialised. We present here the sensors developed for the Segment Alignment Measurement System (SAMS) of the Southern African Large Telescope (SALT). This patented solution represents an important improvement in terms of cost, to market the Position Sensors for Segmented Mirrors of ELTs, whilst maintaining a very high performance level. We present here the concept, the laboratory qualification, and the first trials on the 7 central segments of SALT. The laboratory results are good, and we are now working on the on-site implementation to improve the immunity of the sensors to environment.

  15. Gasdynamic Multiple-Mirror Trap

    Science.gov (United States)

    Beklemishev, Alexei; Anikeev, Andrei; Bagryansky, Peter; Burdakov, Alexander; Gavrilenko, Dmitrii; Ivanov, Alexander; Polosatkin, Sergei; Sinitsky, Stanislav

    2013-10-01

    The new linear device for confinement of fusion plasmas, GDMT, is being developed at the Budker Institute of Nuclear Physics, Novosibirsk. The facility will combine features of existing GOL-3 and GDT devices: the central GDT-like cell with sloshing NBI ions, and the multiple-mirror plugs for suppression of axial losses. Such combination became feasible due to recent discoveries. In particular, the requirement of flute-mode stability can be relaxed by using vortex confinement, achieved by plasma biasing through open field lines. This allows the use of potentially destabilizing multiple-mirror sections. Another key effect is the enhanced multiple-mirror confinement at low densities, which is due to collective rather than coulomb scattering of ions. Hence the multiple-mirror plugs can work at pressures compatible with magnetic confinement. These two main technologies are supplemented by axial injection of pulsed electron beams. Besides additional plasma heating (like in GOL-3), such injection can be used for induced collective scattering in the multiple-mirror plugs and for plasma biasing. The new device is designed to be superconducting and modular. It will be built in stages, with the first stage, GDMT-T, intended for PMI studies. The work was financially supported by Ministry of Education and Science RF.

  16. Metamaterial mirrors in optoelectronic devices

    KAUST Repository

    Esfandyarpour, Majid

    2014-06-22

    The phase reversal that occurs when light is reflected from a metallic mirror produces a standing wave with reduced intensity near the reflective surface. This effect is highly undesirable in optoelectronic devices that use metal films as both electrical contacts and optical mirrors, because it dictates a minimum spacing between the metal and the underlying active semiconductor layers, therefore posing a fundamental limit to the overall thickness of the device. Here, we show that this challenge can be circumvented by using a metamaterial mirror whose reflection phase is tunable from that of a perfect electric mirror († = €) to that of a perfect magnetic mirror († = 0). This tunability in reflection phase can also be exploited to optimize the standing wave profile in planar devices to maximize light-matter interaction. Specifically, we show that light absorption and photocurrent generation in a sub-100 nm active semiconductor layer of a model solar cell can be enhanced by ∼20% over a broad spectral band. © 2014 Macmillan Publishers Limited.

  17. Optical Magnetic Mirrors without Metals

    CERN Document Server

    Liu, Sheng; Mahony, Thomas S; Jun, Young Chul; Campione, Salvatore; Ginn, James; Bender, Daniel A; Wendt, Joel R; Ihlefeld, Jon F; Clem, Paul G; Wright, Jeremy B; Brener, Igal

    2014-01-01

    The reflection of an optical wave from a metal, arising from strong interactions between the optical electric field and the free carriers of the metal, is accompanied by a phase reversal of the reflected electric field. A far less common route to achieve high reflectivity exploits strong interactions between the material and the optical magnetic field to produce a magnetic mirror which does not reverse the phase of the reflected electric field. At optical frequencies, the magnetic properties required for strong interaction can only be achieved through the use of artificially tailored materials. Here we experimentally demonstrate, for the first time, the magnetic mirror behavior of a low-loss, all-dielectric metasurface at infrared optical frequencies through direct measurements of the phase and amplitude of the reflected optical wave. The enhanced absorption and emission of transverse electric dipoles placed very close to magnetic mirrors can lead to exciting new advances in sensors, photodetectors, and light...

  18. Beautiful mirrors at the LHC.

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, K.; Shepherd, W.; Tait, T. M. P.; Vega-Morales, R.; High Energy Physics; Northwestern Univ; Univ. of California at Irvine

    2010-01-01

    We explore the 'Beautiful Mirrors' model, which aims to explain the measured value of A{sub FB}{sup b}, discrepant at the 2.9{sigma} level. This scenario introduces vector-like quarks which mix with the bottom, subtly affecting its coupling to the Z. The spectrum of the new particles consists of two bottom-like quarks and a charge -4/3 quark, all of which have electroweak interactions with the third generation. We explore the phenomenology and discovery reach for these new particles at the LHC, exploring single mirror quark production modes whose rates are proportional to the same mixing parameters which resolve the A{sub FB}{sup b} anomaly. We find that for mirror quark masses {approx}< 500 GeV, a 14 TeV LHC with 300 fb{sup -1} is required to reasonably establish the scenario and extract the relevant mixing parameters.

  19. Composite single crystal silicon scan mirror substrates Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Single crystal silicon is a desirable mirror substrate for scan mirrors in space telescopes. As diameters of mirrors become larger, existing manufacturing...

  20. Mirror Fusion Test Facility magnet

    Energy Technology Data Exchange (ETDEWEB)

    Henning, C.H.; Hodges, A.J.; Van Sant, J.H.; Hinkle, R.E.; Horvath, J.A.; Hintz, R.E.; Dalder, E.; Baldi, R.; Tatro, R.

    1979-11-13

    The Mirror Fusion Test Facility (MFTF) is the largest of the mirror program experiments for magnetic fusion energy. It seeks to combine and extend the near-classical plasma confinement achieved in 2XIIB with the most advanced neutral-beam and magnet technologies. The product of ion density and confinement time will be improved more than an order of magnitude, while the superconducting magnet weight will be extrapolated from the 15 tons in Baseball II to 375 tons in MFTF. Recent reactor studies show that the MFTF will traverse much of the distance in magnet technology towards the reactor regime. Design specifics of the magnet are given. (MOW)

  1. Mirror Fusion Test Facility magnet

    International Nuclear Information System (INIS)

    The Mirror Fusion Test Facility (MFTF) is the largest of the mirror program experiments for magnetic fusion energy. It seeks to combine and extend the near-classical plasma confinement achieved in 2XIIB with the most advanced neutral-beam and magnet technologies. The product of ion density and confinement time will be improved more than an order of magnitude, while the superconducting magnet weight will be extrapolated from the 15 tons in Baseball II to 375 tons in MFTF. Recent reactor studies show that the MFTF will traverse much of the distance in magnet technology towards the reactor regime. Design specifics of the magnet are given

  2. Mirroring patients – or not

    DEFF Research Database (Denmark)

    Davidsen, Annette Sofie; Fosgerau, Christina Fogtmann

    2015-01-01

    For mentalization theorists, implicit mentalization is a key component of all forms of therapy. However, it has been difficult to grasp and to describe precisely how implicit mentalization works. It is said to take place partly by mirroring others in posture, facial expression and vocal tone. Based...... consultations with patients with depression. We wanted to see how implicit mentalizing unfolds in physician–patient interactions. Consultations were videorecorded and analysed within the framework of conversation analysis. GPs and psychiatrists differed substantially in their propensity to mirror body movements...

  3. Mirror Advanced Reactor Study (MARS) plasma heating systems

    International Nuclear Information System (INIS)

    Plasma heating systems are critical to the operation of a high Q tandem mirror reactor. Two electron cyclotron resonance heating (ECRH) systems, a high energy negative ion-based neutral beam, and an anchor ion cyclotron resonance heating (ICRH) system create the proper axial density, pressure and potential profiles in the endcells. The proper profiles electrostatically plug the central cell plasma, and provide an adequate margin with respect to MHD- and micro-stability for the device. An ICRH system in the central cell is also required to heat the plasma to ignition. Each MARS plasma heating system is at a higher power than that has yet been utilized in any fusion experiments; the use of innovative concepts has lead to compact, efficient, and affordable ECRH and negative beam systems. (orig.)

  4. NASA CONNECT: Algebra: Mirror, Mirror on the Universe

    Science.gov (United States)

    2000-01-01

    'Algebra: Mirror, Mirror on the Universe' is the last of seven programs in the 1999-2000 NASA CONNECT series. Produced by NASA Langley Research Center's Office of Education, NASA CONNECT is an award-winning series of instructional programs designed to enhance the teaching of math, science and technology concepts in grades 5-8. NASA CONNECT establishes the 'connection' between the mathematics, science, and technology concepts taught in the classroom and NASA research. Each program in the series supports the national mathematics, science, and technology standards; includes a resource-rich teacher guide; and uses a classroom experiment and web-based activity to complement and enhance the math, science, and technology concepts presented in the program. NASA CONNECT is FREE and the programs in the series are in the public domain. Visit our web site and register. http://connect.larc.nasa.gov In 'Algebra: Mirror, Mirror on the Universe', students will learn how algebra is used to explore the universe.

  5. JAERI Tandem neutron TOF spectrometer

    International Nuclear Information System (INIS)

    The layout of the neutron TOF spectrometer at JAERI Tandem Accelerator for the scattering measurement in 10-40 MeV and the data acquisition/process system are described. The result of the 28Si(n,n) and (n,n') at En=13 MeV is shown and the great improvement of the counting efficiency is obtained. (author)

  6. JAERI tandem annual report, 1982

    International Nuclear Information System (INIS)

    This annual report describes research activities which have been performed with JAERI tandem accelerator from September 1, 1981 to March 31, 1983. Summary reports of 38 papers, publications, personnel and a list of co-operative researches with universities are contained. (author)

  7. JAERI Tandem annual report 1983

    International Nuclear Information System (INIS)

    This annual report describes research activities which have been performed with JAERI tandem accelerator from April 1, 1983 to March 31, 1984. Summary reports of 32 papers, publications, personnel and a list of co-operative reserches with universities are contained. (author)

  8. Emission-Line Profiles of Accretion Disks with a Non-Axisymmetric Pattern

    OpenAIRE

    SANBUICHI, Kiyotaka; FUKUE, Jun; Kojima, Yasufumi

    1994-01-01

    In several cases, accretion disks may have non-axisymmetric patterns, such as one-armed oscillations and spiral shock waves. In such cases the line emissivity may also become non-axisymmetric. We examined the emission-line profiles for geometrically thin/thick, (non-) relativistic accretion disks while taking acount of the non-axisymmetric emissivity. The emission-line profiles were calculated numerically using a code based on the ray-tracing method. The emission-line profiles are usually ...

  9. Mirror Advanced Reactor Study (MARS): executive summary and overview

    Energy Technology Data Exchange (ETDEWEB)

    Logan, B.G.; Perkins, L.J.; Gordon, J.D.

    1984-07-01

    Two self-consistent MARS configurations are discussed - a 1200-MWe commercial electricity-generating plant and a synguels-generating plant that produces hydrogen with an energy equivalent to 26,000 barrels of oil per day. The MARS machine emphasizes the attractive features of the tandem mirror concept, including steady-state operation, a small-diameter high-beta plasma, a linear central cell with simple low-maintenance blankets, low first-wall heat fluxes (<10 W/cm/sup 2/), no driven plasma currents or associated disruptions, natural halo impurity diversion, and direct conversion of end-loss charged-particle power. The MARS electric plant produces 2600 MW of fusion power in a 130-m-long central cell. Advanced tandem-mirror plasma-engineering concepts, a high-efficiency liquid lithium-lead (Li/sub 17/Pb/sub 83/) blanket, and efficient direct electrical conversion of end loss power combine to produce a high net plant efficiency of 36%. With a total capital cost of $2.9 billion (constant 1983 dollars), the MARS electric plant produces busbar electricity at approx. 7 cents/kW-hour. The MARS synfuels plant produces 3500 MW of fusion power in a 150-m-long central cell. A helium-gas-cooled silicon carbide pebble-bed blanket provides high-temperature (1000/sup 0/C) heat to a thermochemical water-splitting cycle and the resulting hydrogen is catalytically converted to methanol for distribution. With a total capital cost of $3.6 billion (constant 1983 dollars), the synfuels plant produces methanol fuel at about $1.7/gal. The major features of the MARS reactor include sloshing-ion thermal barrier plugs for efficient plasma confinement, a high efficiency blanket, high-field (24-T) choke cells, drift pumping for trapped plasma species, quasi-optical electron-cyclotron resonant heating (ECRH) systems, and a component gridless direct converter.

  10. Mirror Advanced Reactor Study (MARS): executive summary and overview

    International Nuclear Information System (INIS)

    Two self-consistent MARS configurations are discussed - a 1200-MWe commercial electricity-generating plant and a synguels-generating plant that produces hydrogen with an energy equivalent to 26,000 barrels of oil per day. The MARS machine emphasizes the attractive features of the tandem mirror concept, including steady-state operation, a small-diameter high-beta plasma, a linear central cell with simple low-maintenance blankets, low first-wall heat fluxes (2), no driven plasma currents or associated disruptions, natural halo impurity diversion, and direct conversion of end-loss charged-particle power. The MARS electric plant produces 2600 MW of fusion power in a 130-m-long central cell. Advanced tandem-mirror plasma-engineering concepts, a high-efficiency liquid lithium-lead (Li17Pb83) blanket, and efficient direct electrical conversion of end loss power combine to produce a high net plant efficiency of 36%. With a total capital cost of $2.9 billion (constant 1983 dollars), the MARS electric plant produces busbar electricity at approx. 7 cents/kW-hour. The MARS synfuels plant produces 3500 MW of fusion power in a 150-m-long central cell. A helium-gas-cooled silicon carbide pebble-bed blanket provides high-temperature (10000C) heat to a thermochemical water-splitting cycle and the resulting hydrogen is catalytically converted to methanol for distribution. With a total capital cost of $3.6 billion (constant 1983 dollars), the synfuels plant produces methanol fuel at about $1.7/gal. The major features of the MARS reactor include sloshing-ion thermal barrier plugs for efficient plasma confinement, a high efficiency blanket, high-field (24-T) choke cells, drift pumping for trapped plasma species, quasi-optical electron-cyclotron resonant heating (ECRH) systems, and a component gridless direct converter

  11. Stability of perturbed geodesics in nD axisymmetric spacetimes

    Science.gov (United States)

    Coimbra-Araújo, C. H.; Anjos, R. C.

    2016-09-01

    The effect of self-gravity of a disk matter is evaluated by the simplest modes of oscillation frequencies for perturbed circular geodesics. We plotted the radial profiles of free oscillations of an equatorial circular geodesic perturbed within the orbital plane or in the vertical direction. The calculation is carried out to geodesics of an axisymmetric n-dimensional spacetime. The profiles are computed by examples of disks embeded in five-dimensional or six-dimensional spacetime, where we studied the motion of free test particles for three axisymmetric cases: (i) the Newtonian limit of a general proposed 5D and 6D axisymmetric spacetime; (ii) a simple Randall–Sundrum (RS) 5D spacetime; (iii) general 5D and 6D RS spacetime. The equation of motion of such particles is derived and the stability study is computed for both horizontal and vertical directions, to see how extra dimensions could affect the system. In particular, we investigate a disk constructed from Miyamoto–Nagai and Chazy–Curzon with a cut parameter to generate a disk potential. Those solutions have a simple extension for extra dimensions in case (i), and by solving vacuum Einstein field equations for a kind of RS–Weyl metric in cases (ii) and (iii). We find that it is possible to compute a range of possible solutions where such perturbed geodesics are stable. Basically, the stable solutions appear, for the radial direction, in special cases when the system has 5D and in all cases when the system has 6D and, for the axial direction, in all cases when the system has both 5D or 6D.

  12. Mirrors for pion spectrometer DIRAC

    Czech Academy of Sciences Publication Activity Database

    Pech, Miroslav; Schovánek, Petr; Hrabovský, Miroslav; Řídký, Jan; Mandát, Dušan; Nožka, Libor; Palatka, Miroslav

    1. Olomouc : Univerzita Palackého v Olomouci, 2006 - (Křepelka, J.), s. 109-110 ISBN 80-244-1544-5 R&D Projects: GA MŠk(CZ) 1M06002 Institutional research plan: CEZ:AV0Z10100522 Keywords : mirrors * pion spectrometer DIRAC Subject RIV: BH - Optics, Masers, Lasers

  13. Shape measuring of ultralight mirrors

    Czech Academy of Sciences Publication Activity Database

    Pech, Miroslav; Hrabovský, Miroslav; Schovánek, Petr; Mandát, Dušan; Nožka, Libor

    Olomouc: Univerzita Palackého v Olomouci, 2007 - (Křepelka, J.), s. 146-150 ISBN 978-80-244-1844-5 R&D Projects: GA MŠk(CZ) 1M06002 Institutional research plan: CEZ:AV0Z10100522 Keywords : ultralight mirror * Hartmann test * Pierre Auger Subject RIV: BH - Optics, Masers, Lasers

  14. A Generalization of Abel Inversion to non axisymmetric density distribution

    CERN Document Server

    Tomassini, P

    2001-01-01

    Abel Inversion is currently used in laser-plasma studies in order to estimate the electronic density $n_e$ from the phase-shift map $\\delta \\phi$ obtained via interferometry. The main limitation of the Abel method is due to the assumption of axial symmetry of the electronic density, which is often hardly fulfilled. In this paper we present an improvement to the Abel inversion technique in which the axial symmetry condition is relaxed by means of a truncated Legendre Polinomial expansion in the azimutal angle. With the help of simulated interferograms, we will show that the generalized Abel inversion generates accurate densities maps when applied to non axisymmetric density sources.

  15. Angle-action estimation in a general axisymmetric potential

    OpenAIRE

    Sanders, Jason

    2012-01-01

    The usefulness of angle-action variables in galaxy dynamics is well known, but their use is limited due to the difficulty of their calculation in realistic galaxy potentials. Here we present a method for estimating angle-action variables in a realistic Milky Way axisymmetric potential by locally fitting a St\\"ackel potential over the region an orbit probes. The quality of the method is assessed by comparison with other known methods for estimating angle-action variables of a range of disc and...

  16. Accuracy Improvement in Magnetic Field Modeling for an Axisymmetric Electromagnet

    Science.gov (United States)

    Ilin, Andrew V.; Chang-Diaz, Franklin R.; Gurieva, Yana L.; Il,in, Valery P.

    2000-01-01

    This paper examines the accuracy and calculation speed for the magnetic field computation in an axisymmetric electromagnet. Different numerical techniques, based on an adaptive nonuniform grid, high order finite difference approximations, and semi-analitical calculation of boundary conditions are considered. These techniques are being applied to the modeling of the Variable Specific Impulse Magnetoplasma Rocket. For high-accuracy calculations, a fourth-order scheme offers dramatic advantages over a second order scheme. For complex physical configurations of interest in plasma propulsion, a second-order scheme with nonuniform mesh gives the best results. Also, the relative advantages of various methods are described when the speed of computation is an important consideration.

  17. Frequency spectrum of axisymmetric horizontal oscillations in accretion disks

    CERN Document Server

    Giussani, L; Mishra, B

    2015-01-01

    We present the spectrum of eigenfrequencies of axisymmetric acoustic-inertial oscillations of thin accretion disks for a Schwarzschild black hole modeled with a pseudo-potential. There are nine discrete frequencies, corresponding to trapped modes. Eigenmodes with nine or more radial nodes in the inner disk belong to the continuum, whose frequency range starts somewhat below the maximum value of the radial epicyclic frequency. The results are derived under the assumption that the oscillatory motion is parallel to the midplane of the disk.

  18. Note on reflection symmetry in stationary axisymmetric electrovacuum spacetimes

    Energy Technology Data Exchange (ETDEWEB)

    Pachon, Leonardo A [Laboratorio de Astronomia y Fisica Teorica (LAFT), Departamento de Fisica, Facultad de Ciencias, La Universidad del Zulia, Maracaibo, 4004 (Venezuela); Sanabria-Gomez, Jose D [Escuela de Fisica, Universidad Industrial de Santander. A.A. 678, Bucaramanga (Colombia)

    2006-05-07

    Recently, Kordas (1995 Class. Quantum Grav. 12 2037) and Meinel and Neugebauer (1995 Class. Quantum Grav. 12 2045) studied the conditions for reflection symmetry in stationary axisymmetric spacetimes in vacuum. They found that a solution to the Einstein field equations is reflectionally symmetric if their Ernst potential E ({rho} = 0, z) = e(z) on a portion of the positive z-axis extending to infinity satisfies the condition e{sub +}(z)e*{sub +}(-z) = 1. In this note, we formulate analogous conditions for two complex Ernst potentials in electrovacuum. We also present the special case of rational axis potentials. (comments, replies and notes)

  19. Diffusive dynamics and stochastic models of turbulent axisymmetric wakes

    CERN Document Server

    Rigas, G; Brackston, R D; Morrison, J F

    2015-01-01

    A modelling methodology to reproduce the experimental measurements of a turbulent flow under the presence of symmetry is presented. The flow is a three-dimensional wake generated by an axisymmetric body. We show that the dynamics of the turbulent wake- flow can be assimilated by a nonlinear two-dimensional Langevin equation, the deterministic part of which accounts for the broken symmetries which occur at the laminar and transitional regimes at low Reynolds numbers and the stochastic part of which accounts for the turbulent fluctuations. Comparison between theoretical and experimental results allows the extraction of the model parameters.

  20. Axisymmetric flows from fluid injection into a confined porous medium

    Science.gov (United States)

    Guo, Bo; Zheng, Zhong; Celia, Michael A.; Stone, Howard A.

    2016-02-01

    We study the axisymmetric flows generated from fluid injection into a horizontal confined porous medium that is originally saturated with another fluid of different density and viscosity. Neglecting the effects of surface tension and fluid mixing, we use the lubrication approximation to obtain a nonlinear advection-diffusion equation that describes the time evolution of the sharp fluid-fluid interface. The flow behaviors are controlled by two dimensionless groups: M, the viscosity ratio of displaced fluid relative to injected fluid, and Γ, which measures the relative importance of buoyancy and fluid injection. For this axisymmetric geometry, the similarity solution involving R2/T (where R is the dimensionless radial coordinate and T is the dimensionless time) is an exact solution to the nonlinear governing equation for all times. Four analytical expressions are identified as asymptotic approximations (two of which are new solutions): (i) injection-driven flow with the injected fluid being more viscous than the displaced fluid (Γ ≪ 1 and M interface shape; (ii) injection-driven flow with injected and displaced fluids of equal viscosity (Γ ≪ 1 and M = 1), where we find a self-similar solution that predicts a distinct parabolic interface shape; (iii) injection-driven flow with a less viscous injected fluid (Γ ≪ 1 and M > 1) for which there is a rarefaction wave solution, assuming that the Saffman-Taylor instability does not occur at the reservoir scale; and (iv) buoyancy-driven flow (Γ ≫ 1) for which there is a well-known self-similar solution corresponding to gravity currents in an unconfined porous medium [S. Lyle et al. "Axisymmetric gravity currents in a porous medium," J. Fluid Mech. 543, 293-302 (2005)]. The various axisymmetric flows are summarized in a Γ-M regime diagram with five distinct dynamic behaviors including the four asymptotic regimes and an intermediate regime. The implications of the regime diagram are discussed using practical

  1. Fusion-product transport in axisymmetric tokamaks: losses and thermalization

    International Nuclear Information System (INIS)

    High-energy fusion-product losses from an axisymmetric tokamak plasma are studied. Prompt-escape loss fluxes (i.e. prior to slowing down) are calculated including the non-separable dependence of flux as a function of poloidal angle and local angle-of-incidence at the first wall. Fusion-product (fp) thermalization and heating are calculated assuming classical slowing down. The present analytical model describes fast ion orbits and their distribution function in realistic, high-β, non-circular tokamak equilibria. First-orbit losses, trapping effects, and slowing-down drifts are also treated

  2. Axisymmetrical bending of circular plates with eccentric stiffeners

    International Nuclear Information System (INIS)

    Small deflection bending theory of stiffened circular plates with uniformly spaced radial and circunferential ribs is presented. Equilibrium differential equations for the axisymmetric case, in terms of the displacements u and w of the middle surface of the plate are derived, and their general solutions are found. Closed form solutions for the circular plate with uniformly distributed bending moments along its edge are given for the special case in which geometrical and elastic properties of the ribs are constant and equal along both radial and circunferential directions. (Author)

  3. Causal Structure of d=5 Vacua and Axisymmetric Spacetimes

    CERN Document Server

    Fiol, B; Lozano-Tellechea, E; Fiol, Bartomeu; Hofman, Christiaan; Lozano-Tellechea, Ernesto

    2004-01-01

    We study the structure of closed timelike curves (CTCs) for the near horizon limit of the five dimensional BMPV black hole, in its overrotating regime. We argue that Bousso's holographic screens are inside the chronologically safe region, extending a similar observation of Boyda et al. hep-th/0212087 for Goedel type solutions. We then extend this result to quite generic axisymmetric spacetimes with CTCs, showing that causal geodesics can't escape the chronologically safe region. As a spin-off of our results, we fill a gap in the identification of all maximally supersymmetric solutions of minimal five dimensional supergravity, bringing this problem to a full conclusion.

  4. MRI-driven Accretion onto Magnetized stars: Axisymmetric MHD Simulations

    OpenAIRE

    Romanova, Marina M.; Ustyugova, Galina V.; Koldoba, Alexander V.; Lovelace, Richard V. E.

    2011-01-01

    We present the first results of a global axisymmetric simulation of accretion onto rotating magnetized stars from a turbulent, MRI-driven disk. The angular momentum is transported outward by the magnetic stress of the turbulent flow with a rate corresponding to a Shakura-Sunyaev viscosity parameter alpha\\approx 0.01-0.04. The result of the disk-magnetosphere interaction depends on the orientation of the poloidal field in the disk relative to that of the star at the disk-magnetosphere boundary...

  5. Maximum-J capability in a quasi-axisymmetric stellarator

    International Nuclear Information System (INIS)

    Maximum-J (J is the second adiabatic invariant) capability, i,e., the radial derivative of J has the same sign as that of pressure, is investigated in a quasi-axisymmetric (QA) stellarator to investigate improved confinement. Due to the existence of non-axisymmetry of the magnetic field strength, a local maximum of J is created to cause the drift reversal. External controllability of Maximum-J condition is also demonstrated, by which impact of magnetic configuration on turbulent transport can be studied. (author)

  6. A high-precision algorithm for axisymmetric flow

    Directory of Open Access Journals (Sweden)

    Gokhman A.

    1995-01-01

    Full Text Available We present a new algorithm for highly accurate computation of axisymmetric potential flow. The principal feature of the algorithm is the use of orthogonal curvilinear coordinates. These coordinates are used to write down the equations and to specify quadrilateral elements following the boundary. In particular, boundary conditions for the Stokes' stream-function are satisfied exactly. The velocity field is determined by differentiating the stream-function. We avoid the use of quadratures in the evaluation of Galerkin integrals, and instead use splining of the boundaries of elements to take the double integrals of the shape functions in closed form. This is very accurate and not time consuming.

  7. Axisymmetric Turbulent Wakes with New Nonequilibrium Similarity Scalings

    Science.gov (United States)

    Nedić, J.; Vassilicos, J. C.; Ganapathisubramani, B.

    2013-10-01

    The recently discovered nonequilibrium turbulence dissipation law implies the existence of axisymmetric turbulent wake regions where the mean flow velocity deficit decays as the inverse of the distance from the wake-generating body and the wake width grows as the square root of that distance. This behavior is different from any documented boundary-free turbulent shear flow to date. Its existence is confirmed in wind tunnel experiments of wakes generated by plates with irregular edges placed normal to an incoming free stream. The wake characteristics of irregular bodies such as buildings, bridges, mountains, trees, coral reefs, and wind turbines are critical in many areas of environmental engineering and fluid mechanics.

  8. An axisymmetric PFEM formulation for bottle forming simulation

    Science.gov (United States)

    Ryzhakov, Pavel B.

    2016-05-01

    A numerical model for bottle forming simulation is proposed. It is based upon the Particle Finite Element Method (PFEM) and is developed for the simulation of bottles characterized by rotational symmetry. The PFEM strategy is adapted to suit the problem of interest. Axisymmetric version of the formulation is developed and a modified contact algorithm is applied. This results in a method characterized by excellent computational efficiency and volume conservation characteristics. The model is validated. An example modelling the final blow process is solved. Bottle wall thickness is estimated and the mass conservation of the method is analysed.

  9. MIRROR THERAPY: A REVIEW OF EVIDENCES

    Directory of Open Access Journals (Sweden)

    Aishath Najiha

    2015-06-01

    Full Text Available The aim of this review was to identify and summarize the existing evidences on mirror box therapy for the management of various musculoskeletal conditions. A systemic literature search was performed to identify studies concerning mirror therapy. The included journal articles were reviewed and assessed for its significance. Fifty one studies were identified and reviewed. Five different patient categories were studied: 24 studies focussed on mirror therapy after stroke, thirteen studies focussed on mirror therapy after an amputation, three studies focussed on mirror therapy with complex regional pain syndrome patients, two studies on mirror therapy for cerebral palsy and one study focussed on mirror therapy after a fracture. The articles reviewed showed a trend that mirror therapy is effective in stroke, phantom limb pain, complex regional pain syndrome, cerebral palsy and fracture rehabilitation.

  10. Thin fieldlight mirror for medical electron accelerators

    International Nuclear Information System (INIS)

    A mirror for reflecting visible light to simulate the radiation field of a medical electron beam applicator is described. It is made of a thin film of a plastic material with superior resistance to radiation damage so that the applicator requires no power-driven moving parts to retract the mirror and the mirror can be left fixed in the beam. (author)

  11. Design of a separator/neutralizer to limit impurities and non-primary species in the Mirror Fusion Test Facility

    International Nuclear Information System (INIS)

    The optimum plasma for the tandem Mirror Fusion Test Facility (MFTF-B) at Lawrence Livermore National Laboratory (LLNL) is very sensitive to heavy contaminates, such as oxygen and metals. Unfortunately the current neutral beam sources generate not only high energy deuterium particles but also high energy oxygen particles. A new MFTF-B separator/neutralizer has been designed to filter out the unwanted oxygen and allow only primary species neutrals to reach the plasma

  12. Application of the Least Squares Method in Axisymmetric Biharmonic Problems

    Directory of Open Access Journals (Sweden)

    Vasyl Chekurin

    2016-01-01

    Full Text Available An approach for solving of the axisymmetric biharmonic boundary value problems for semi-infinite cylindrical domain was developed in the paper. On the lateral surface of the domain homogeneous Neumann boundary conditions are prescribed. On the remaining part of the domain’s boundary four different biharmonic boundary pieces of data are considered. To solve the formulated biharmonic problems the method of least squares on the boundary combined with the method of homogeneous solutions was used. That enabled reducing the problems to infinite systems of linear algebraic equations which can be solved with the use of reduction method. Convergence of the solution obtained with developed approach was studied numerically on some characteristic examples. The developed approach can be used particularly to solve axisymmetric elasticity problems for cylindrical bodies, the heights of which are equal to or exceed their diameters, when on their lateral surface normal and tangential tractions are prescribed and on the cylinder’s end faces various types of boundary conditions in stresses in displacements or mixed ones are given.

  13. Nonlinear fluid-structure interaction of axisymmetric systems

    International Nuclear Information System (INIS)

    Full text: Various numerical procedures, which each have respective merits and drawbacks, are available for the investigation of fluid-structure interaction problems. This paper concentrates on the coupling of the finite element method (FEM) for modeling the structure and the boundary element method (BEM) used to represent the compressible, inviscid fluid. Both methods are formulated in the time domain and a special algorithm is developed to realize the coupling. In particular, nonlinear effects, such as material nonlinearities, large displacements or unilateral boundary conditions, may be taken into account in the structural model, while on infinite expansion of the fluid region is included in the boundary element formulation. For axisymmetric systems, the number of degrees of freedom can be decreased considerably compared to the full three-dimensional situation. Whereas a suitable FE formulation for axisymmetric elastodynamic problems is well-known, the transient fundamental solution for the scalar wave propagation in the BE domain had to be determined numerically up to now. In this contribution an explicit form of this fundamental solution is developed. The numerical results obtained for a simply-shaped geometry and its analytical solution match very well. With this new approach more complicated nonlinear coupled systems like fluid-filled pipes, submerged structures or cylindrical tanks can be simulated without depending too muck on available computer resources. Refs. 3 (author)

  14. Coupling of Applied Non-axisymmetric Fields to Toroidal Torque

    Science.gov (United States)

    Logan, N. C.; Park, J.-K.; Menard, J. E.; Strait, E. J.; Paz-Soldan, C.; Lanctot, M. J.

    2014-10-01

    Recent advances in the modeling of neoclassical toroidal viscosity (NTV) have enabled realistic predictions of the coupling between applied non-axisymmetric fields and the resultant toroidal torque in the DIII-D tokamak. The strong dependence of the NTV on the amplified plasma kink response reduces the control of the non-resonant torque to a single mode model, in which the torque optimization is equivalent to an optimization of the net non-axisymmetric field's overlap with the spatial structure of the dominant mode. This single mode model has enabled efficient feed-forward correction of the n = 1 and n = 2 intrinsic error fields and n = 1-3 proxy error fields in NTV dominated scenarios. In addition, rotation drive toward a neoclassical offset using multiple coil sets has been optimized in accordance with the single mode model. Similar linear optimization techniques could be used to design future coil sets for rotation control, while inclusion of multimodal effects will be necessary for rotation profile control. Work supported by the US Department of Energy under DE-AC02-09CH11466 and DE-FC02-04ER54698.

  15. Non-axisymmetric instabilities in discs with imposed zonal flows

    CERN Document Server

    Vanon, R

    2016-01-01

    We conduct a linear stability calculation of an ideal Keplerian flow on which a sinusoidal zonal flow is imposed. The analysis uses the shearing sheet model and is carried out both in isothermal and adiabatic conditions, with and without self-gravity (SG). In the non-SG regime a structure in the potential vorticity (PV) leads to a non-axisymmetric Kelvin-Helmholtz (KH) instability; in the short-wavelength limit its growth rate agrees with the incompressible calculation by Lithwick (2007), which only considers perturbations elongated in the streamwise direction. The instability's strength is analysed as a function of the structure's properties, and zonal flows are found to be stable if their wavelength is $\\gtrsim 8H$, where $H$ is the disc's scale height, regardless of the value of the adiabatic index $\\gamma$. The non-axisymmetric KH instability can operate in Rayleigh-stable conditions, and it therefore represents the limiting factor to the structure's properties. Introducing SG triggers a second non-axisym...

  16. Aerodynamic Flow Control of a Moving Axisymmetric Platform

    Science.gov (United States)

    Lambert, Thomas J.; Vukasinovic, Bojan; Glezer, Ari

    2013-11-01

    Active fluidic control of induced aerodynamic forces and moments on a moving axisymmetric platform is investigated in wind tunnel experiments. Actuation is effected by controlled interactions between an azimuthal array of integrated synthetic jets with the cross flow to induce localized flow attachment domains over the aft end of the model and thereby alter the global aerodynamic forces and moments. The axisymmetric platform is wire-mounted on a 6 DOF traverse such that each of the eight mounting wires is connected to a servo motor with an in-line load cell for monitoring the wire tension. The desired platform motion is controlled in closed-loop by a laboratory computer. The effects of continuous and transitory actuation on the induced aerodynamic forces of the moving platform are investigated in detail using high-speed PIV. The time-dependent changes in the forces are explored for model maneuvering and stabilization. It is found that the actuation induces forces and moments that are on the order of the forces and moments of the baseline flow. These measurements agree with preliminary results on the stabilization of a model moving in a single DOF demonstrating the effectiveness of the actuation for trajectory stabilization. Supported by the ARO.

  17. Non-axisymmetrical freeform design for short LED street lamp

    Science.gov (United States)

    Jen, Ching-Hsuan; Chen, Yi-Yung; Whang, Allen Jong-Woei; Lu, Ming-Jun

    2011-10-01

    Based on energy savings trend, LED has been developing as the main force of the future lighting, especially the road lighting. For controlling the intensity distribution of LED, the concept of freeform design has been proposed in many articles with transmission or reflection components but mainly focus on axial symmetrical types or dual axial symmetrical types. We, in this paper, design a non-axisymmetrical freeform system applying in a short LED street lamp whose dimension is 10cm (W) x 10cm (L) x 7cm (H) that has an advantage, easy maintaining. For coordinate transformation and simplifying the non- axisymmetrical system, we create two virtual surfaces and design the slope of each discrete point on the freeform surface to control the light path between the two virtual surfaces and avoid the total internal reflection. The short street lamp has four LEDs to light 3m square and each LED light a triangle area. According to the simulation results, the uniformity of illumination is 1:3 and the optical efficiency is more than 80% that meet the legal requirements of street lamp. In short, to reduce manufacturing and maintenance costs, the proposed design is appropriate to use in the actual lighting on the road and to replace the traditional street lamps.

  18. Two-Dimensional Axisymmetric Collapse of Thermally Unstable Primordial Clouds

    CERN Document Server

    Baek, C H; Ryu, D; Baek, Chang Hyun; Kang, Hyesung; Ryu, Dongsu

    2003-01-01

    We have performed two-dimensional hydrodynamic simulations of the collapse of isolated axisymmetric clouds condensing via radiative cooling in a primordial background gas. In order to study the development of the so-called ``shape-instability'', we have considered two types of axisymmetric clouds, oblate and prolate clouds of various sizes and with axial ratios of $0.5 \\leq {R_{\\rm c,R}} /{R_{\\rm c,z}} \\leq 2$. We find that the degree of oblateness or prolateness is enhanced during the initial cooling phase. But it can be reversed later, if the initial contrast in cooling times between the cloud gas and the background gas is much greater than one. In such cases an oblate cloud collapses to a structure composed of an outer thin disk and a central prolate component. A prolate cloud, on the other hand, becomes a thin cigar-shape structure with a central dense oblate component. The reversal of shape in the central part of the cooled clouds is due to supersonic motions either along the disk plane in the case of ob...

  19. SEAWAT-based simulation of axisymmetric heat transport.

    Science.gov (United States)

    Vandenbohede, Alexander; Louwyck, Andy; Vlamynck, Nele

    2014-01-01

    Simulation of heat transport has its applications in geothermal exploitation of aquifers and the analysis of temperature dependent chemical reactions. Under homogeneous conditions and in the absence of a regional hydraulic gradient, groundwater flow and heat transport from or to a well exhibit radial symmetry, and governing equations are reduced by one dimension (1D) which increases computational efficiency importantly. Solute transport codes can simulate heat transport and input parameters may be modified such that the Cartesian geometry can handle radial flow. In this article, SEAWAT is evaluated as simulator for heat transport under radial flow conditions. The 1971, 1D analytical solution of Gelhar and Collins is used to compare axisymmetric transport with retardation (i.e., as a result of thermal equilibrium between fluid and solid) and a large diffusion (conduction). It is shown that an axisymmetric simulation compares well with a fully three dimensional (3D) simulation of an aquifer thermal energy storage systems. The influence of grid discretization, solver parameters, and advection solution is illustrated. Because of the high diffusion to simulate conduction, convergence criterion for heat transport must be set much smaller (10(-10) ) than for solute transport (10(-6) ). Grid discretization should be considered carefully, in particular the subdivision of the screen interval. On the other hand, different methods to calculate the pumping or injection rate distribution over different nodes of a multilayer well lead to small differences only. PMID:24571415

  20. Finite axisymmetric charged dust disks in conformastatic spacetimes

    Science.gov (United States)

    González, Guillermo A.; Gutiérrez-Piñeres, Antonio C.; Ospina, Paolo A.

    2008-09-01

    An infinite family of axisymmetric charged dust disks of finite extension is presented. The disks are obtained by solving the vacuum Einstein-Maxwell equations for conformastatic spacetimes, which are characterized by only one metric function. In order to obtain the solutions, a functional relationship between the metric function and the electric potential is assumed. It is also assumed that the metric function is functionally dependent on another auxiliary function, which is taken as a solution of the Laplace equation. The solutions for the auxiliary function are then taken as given by the infinite family of generalized Kalnajs disks recently obtained by González and Reina [G. A. González and J. I. Reina, Mon. Not. R. Astron. Soc. 371, 1873 (2006).MNRAA40035-871110.1111/j.1365-2966.2006.10819.x], expressed in terms of the oblate spheroidal coordinates and corresponding to a family of well-behaved Newtonian axisymmetric thin disks of finite radius. The obtained relativistic thin disks have a charge density that is equal, except maybe by a sign, to their mass density, in such a way that the electric and gravitational forces are in exact balance. The energy density of the disks is everywhere positive and well behaved, vanishing at the edge. Accordingly, as the disks are made of dust, their energy-momentum tensor agrees with all the energy conditions.

  1. Finite axisymmetric charged dust disks in conformastatic spacetimes

    CERN Document Server

    Gonzalez, Guillermo A; Ospina, Paolo A

    2008-01-01

    An infinite family of axisymmetric charged dust disks of finite extension is presented. The disks are obtained by solving the vacuum Einstein-Maxwell equations for conformastatic spacetimes, which are characterized by only one metric function. In order to obtain the solutions, it is assumed that the metric function and the electric potential are functionally related and that the metric function is functionally dependent of another auxiliary function, which is taken as a solution of Laplace equation. The solutions for the auxiliary function are then taken as given by the infinite family of generalized Kalnajs disks recently obtained by Gonz\\'alez and Reina (MNRAS 371, 1873, 2006), which is expressed in terms of the oblate spheroidal coordinates and represents a well behaved family of finite axisymmetric flat galaxy models. The so obtained relativistic thin disks have then a charge density that is equal, except maybe by a sign, to their mass density, in such a way that the electric and gravitational forces are ...

  2. Finite axisymmetric charged dust disks in conformastatic spacetimes

    International Nuclear Information System (INIS)

    An infinite family of axisymmetric charged dust disks of finite extension is presented. The disks are obtained by solving the vacuum Einstein-Maxwell equations for conformastatic spacetimes, which are characterized by only one metric function. In order to obtain the solutions, a functional relationship between the metric function and the electric potential is assumed. It is also assumed that the metric function is functionally dependent on another auxiliary function, which is taken as a solution of the Laplace equation. The solutions for the auxiliary function are then taken as given by the infinite family of generalized Kalnajs disks recently obtained by Gonzalez and Reina [G. A. Gonzalez and J. I. Reina, Mon. Not. R. Astron. Soc. 371, 1873 (2006).], expressed in terms of the oblate spheroidal coordinates and corresponding to a family of well-behaved Newtonian axisymmetric thin disks of finite radius. The obtained relativistic thin disks have a charge density that is equal, except maybe by a sign, to their mass density, in such a way that the electric and gravitational forces are in exact balance. The energy density of the disks is everywhere positive and well behaved, vanishing at the edge. Accordingly, as the disks are made of dust, their energy-momentum tensor agrees with all the energy conditions.

  3. Aerodynamics characteristic of axisymmetric surface protuberance in supersonic regime

    KAUST Repository

    Qamar, Adnan

    2012-01-01

    The present work deals with the problem of an axi-symmetric surface protuberance mounted on a spherical nosed body of revolution. The numerical computations are carried out for laminar supersonic viscous flow for trapezoidal shape axi-symmetric protuberances. A free stream Mach number ranging from 3 to 8 in steps of 1 at a fixed free stream Reynolds number of 1.8x10(4) has been used in the present study. The steady solutions are obtained using a time marching approach. A newly developed Particle Velocity Upwinding (PVU) scheme has been used for the computation. The spatial flow pattern exhibits a strong bow shock in front of the hemispherical nose, which engulfs the entire base body. Near the protuberance, the fluid particle decelerates due to the adverse pressure created by the protuberance and thus the flow separates in front of the protuberance. This point of separation is found to be a function of Mach number and the protuberance shape. A low-pressure expansion region dominates the base region of the obstacle. The reattachment point for the base separation is also a function of Mach number. As the Mach number is increased the reattachment point shifts toward the protuberances base. A weak recompression shock is also seen in the base, which affects the separated zone behind the protuberance. The important design parameters such as skin friction, heat transfer, drag, and surface pressure coefficients are reported extensively.

  4. Nanocrystal assembly for tandem catalysis

    Science.gov (United States)

    Yang, Peidong; Somorjai, Gabor; Yamada, Yusuke; Tsung, Chia-Kuang; Huang, Wenyu

    2014-10-14

    The present invention provides a nanocrystal tandem catalyst comprising at least two metal-metal oxide interfaces for the catalysis of sequential reactions. One embodiment utilizes a nanocrystal bilayer structure formed by assembling sub-10 nm platinum and cerium oxide nanocube monolayers on a silica substrate. The two distinct metal-metal oxide interfaces, CeO.sub.2--Pt and Pt--SiO.sub.2, can be used to catalyze two distinct sequential reactions. The CeO.sub.2--Pt interface catalyzed methanol decomposition to produce CO and H.sub.2, which were then subsequently used for ethylene hydroformylation catalyzed by the nearby Pt--SiO.sub.2 interface. Consequently, propanal was selectively produced on this nanocrystal bilayer tandem catalyst.

  5. The VST secondary mirror support system

    Science.gov (United States)

    Schipani, P.; Perrotta, F.; Molfese, C.; Caputi, O.; Ferragina, L.; Marty, L.; Capaccioli, M.; Gallieni, D.; Fumi, P.; Anaclerio, E.; Lazzarini, P.; De Paris, G.

    2008-07-01

    The VST telescope is equipped with an active optics system based on a wavefront sensor, a set of axial actuators to change the primary mirror shape and a secondary mirror positioner stage. The secondary mirror positioning capability allows the correction of defocus and coma optical aberrations, mainly caused by incorrect relative positions of the optics. The secondary mirror positioner is a 6-6 Stewart platform (also called "hexapod"). It is a parallel robot with a mobile platform moved by 6 linear actuators acting simultaneously. This paper describes the secondary mirror support system and the current status of the work.

  6. "Nanocrystal bilayer for tandem catalysis"

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Yusuke; Tsung, Chia Kuang; Huang, Wenyu; Huo, Ziyang; E.Habas, Susan E; Soejima, Tetsuro; Aliaga, Cesar E; Samorjai, Gabor A; Yang, Peidong

    2011-01-24

    Supported catalysts are widely used in industry and can be optimized by tuning the composition and interface of the metal nanoparticles and oxide supports. Rational design of metal-metal oxide interfaces in nanostructured catalysts is critical to achieve better reaction activities and selectivities. We introduce here a new class of nanocrystal tandem catalysts that have multiple metal-metal oxide interfaces for the catalysis of sequential reactions. We utilized a nanocrystal bilayer structure formed by assembling platinum and cerium oxide nanocube monolayers of less than 10 nm on a silica substrate. The two distinct metal-metal oxide interfaces, CeO2-Pt and Pt-SiO2, can be used to catalyse two distinct sequential reactions. The CeO2-Pt interface catalysed methanol decomposition to produce CO and H2, which were subsequently used for ethylene hydroformylation catalysed by the nearby Pt-SiO2 interface. Consequently, propanal was produced selectively from methanol and ethylene on the nanocrystal bilayer tandem catalyst. This new concept of nanocrystal tandem catalysis represents a powerful approach towards designing high-performance, multifunctional nanostructured catalysts

  7. Effects of Large-scale Non-axisymmetric Perturbations in the Mean-field Solar Dynamo.

    Science.gov (United States)

    Pipin, V. V.; Kosovichev, A. G.

    2015-11-01

    We explore the response of a nonlinear non-axisymmetric mean-field solar dynamo model to shallow non-axisymmetric perturbations. After a relaxation period, the amplitude of the non-axisymmetric field depends on the initial condition, helicity conservation, and the depth of perturbation. It is found that a perturbation that is anchored at 0.9 R⊙ has a profound effect on the dynamo process, producing a transient magnetic cycle of the axisymmetric magnetic field, if it is initiated at the growing phase of the cycle. The non-symmetric, with respect to the equator, perturbation results in a hemispheric asymmetry of the magnetic activity. The evolution of the axisymmetric and non-axisymmetric fields depends on the turbulent magnetic Reynolds number Rm. In the range of Rm = 104-106 the evolution returns to the normal course in the next cycle, in which the non-axisymmetric field is generated due to a nonlinear α-effect and magnetic buoyancy. In the stationary state, the large-scale magnetic field demonstrates a phenomenon of “active longitudes” with cyclic 180° “flip-flop” changes of the large-scale magnetic field orientation. The flip-flop effect is known from observations of solar and stellar magnetic cycles. However, this effect disappears in the model, which includes the meridional circulation pattern determined by helioseismology. The rotation rate of the non-axisymmetric field components varies during the relaxation period and carries important information about the dynamo process.

  8. Topological Fluid Mechanics with Applications to Free Surfaces and Axisymmetric Flows

    DEFF Research Database (Denmark)

    Brøns, Morten

    1996-01-01

    Topological fluid mechanics is the study of qualitative features of fluid patterns. We discuss applications to the flow beneath a stagnant surface film, and to patterns in axisymmetric flow.......Topological fluid mechanics is the study of qualitative features of fluid patterns. We discuss applications to the flow beneath a stagnant surface film, and to patterns in axisymmetric flow....

  9. Design of a rapidly cooled cryogenic mirror

    Science.gov (United States)

    Plummer, Ron; Hsu, Ike

    1993-01-01

    The paper discusses the design, analysis, and testing of a rapidly cooled beryllium cryogenic mirror, which is the primary mirror in the four-element optical system for the Long Wavelength Infrared Advanced Technology Seeker. The mirror is shown to meet the requirement of five minutes for cooling to cryogenic operating temperature; it also maintains its optical figure and vacuum integrity and meets the nuclear specification. Results of a detailed thermal analysis on the mirror showed that, using nitrogen gas at 80 K as coolant, the front face of the mirror can be cooled from an initial temperature of 300 K to less than 90 K within five minutes. In a vacuum chamber, using liquid nitrogen as coolant, the mirror can be cooled to 80 K within 1.5 min. The mirror is well thermally insulated, so that it can be maintained at less than its operating temperature for a long time without active cooling.

  10. Design of precise lightweight mirror

    Czech Academy of Sciences Publication Activity Database

    Vít, Tomáš; Melich, Radek; Václavík, Jan; Lédl, Vít

    Vol. 284-287. Zürich : Trans Tech Publications, 2013 - (Hsieh, W.), s. 2717-2722 ISSN 1660-9336. [International Conference on Engineering and Technology Innovation 2012 (ICETI 2012)/2./. Kaohsiung (TW), 02.11.2012-06.11.2012] R&D Projects: GA MŠk(CZ) ED2.1.00/03.0079 Institutional support: RVO:61389021 Keywords : SiSiC * lightweight mirrors * precise optics Subject RIV: JV - Space Technology

  11. Mirror versus parallel bimanual reaching

    OpenAIRE

    Abdollahi, Farnaz; Kenyon, Robert V.; Patton, James L.

    2013-01-01

    Background In spite of their importance to everyday function, tasks that require both hands to work together such as lifting and carrying large objects have not been well studied and the full potential of how new technology might facilitate recovery remains unknown. Methods To help identify the best modes for self-teleoperated bimanual training, we used an advanced haptic/graphic environment to compare several modes of practice. In a 2-by-2 study, we compared mirror vs. parallel reaching move...

  12. Axisymmetric equilibria with pressure anisotropy and plasma flow

    CERN Document Server

    Evangelias, A

    2016-01-01

    A generalised Grad-Shafranov equation that governs the equilibrium of an axisymmetric toroidal plasma with anisotropic pressure and incompressible flow of arbitrary direction is derived. This equation includes six free surface functions and recovers known Grad-Shafranov-like equations in the literature as well as the usual static, isotropic one. The form of the generalised equation indicates that pressure anisotropy and flow act additively on equilibrium. In addition, two sets of analytical solutions, an extended Solovev one with a plasma reaching the separatrix and an extended Hernegger-Maschke one for a plasma surrounded by a fixed boundary possessing an X-point, are constructed, particularly in relevance to the ITER and NSTX tokamaks. Furthermore, the impacts both of pressure anisotropy and plasma flow on these equilibria are examined. It turns out that depending on the maximum value and the shape of an anisotropy function, the anisotropy can act either paramagnetically or diamagnetically. Also, in most of...

  13. Free Vibrations of Axisymmetric Shells: Parabolic and Elliptic cases

    CERN Document Server

    Chaussade, Marie; Faou, Erwan; Yosibash, Zohar

    2016-01-01

    Approximate eigenpairs (quasimodes) of axisymmetric thin elastic domains with laterally clamped boundary conditions (Lam\\'e system) are determined by an asymptotic analysis as the thickness ($2\\varepsilon$) tends to zero. The departing point is the Koiter shell model that we reduce by asymptotic analysis to a scalar modelthat depends on two parameters: the angular frequency $k$ and the half-thickness $\\varepsilon$. Optimizing $k$ for each chosen $\\varepsilon$, we find power laws for $k$ in function of $\\varepsilon$ that provide the smallest eigenvalues of the scalar reductions.Corresponding eigenpairs generate quasimodes for the 3D Lam\\'e system by means of several reconstruction operators, including boundary layer terms. Numerical experiments demonstrate that in many cases the constructed eigenpair corresponds to the first eigenpair of the Lam\\'e system.Geometrical conditions are necessary to this approach: The Gaussian curvature has to be nonnegative and the azimuthal curvature has to dominate the meridian ...

  14. Multigrid solver for axisymmetrical 2D fluid equations

    CERN Document Server

    Ristivojevic, Zoran

    2008-01-01

    We have developed an efficient algorithm for steady axisymmetrical 2D fluid equations. The algorithm employs multigrid method as well as standard implicit discretization schemes for systems of partial differential equations. Linearity of the multigrid method with respect to the number of grid points allowed us to use $256\\times 256$ grid, where we could achieve solutions in several minutes. Time limitations due to nonlinearity of the system are partially avoided by using multi level grids(the initial solution on $256\\times 256$ grid was extrapolated steady solution from $128\\times 128$ grid which allowed using "long" integration time steps). The fluid solver may be used as the basis for hybrid codes for DC discharges.

  15. Axisymmetric smoothed particle hydrodynamics with self-gravity

    CERN Document Server

    García-Senz, D; Cabezon, R M; Bravo, E

    2008-01-01

    The axisymmetric form of the hydrodynamic equations within the smoothed particle hydrodynamics (SPH) formalism is presented and checked using idealized scenarios taken from astrophysics (free fall collapse, implosion and further pulsation of a sun-like star), gas dynamics (wall heating problem, collision of two streams of gas) and inertial confinement fusion (ICF, -ablative implosion of a small capsule-). New material concerning the standard SPH formalism is given. That includes the numerical handling of those mass points which move close to the singularity axis, more accurate expressions for the artificial viscosity and the heat conduction term and an easy way to incorporate self-gravity in the simulations. The algorithm developed to compute gravity does not rely in any sort of grid, leading to a numerical scheme totally compatible with the lagrangian nature of the SPH equations.

  16. Axisymmetric buckling of laminated, moderately thick shallow conical cap

    Energy Technology Data Exchange (ETDEWEB)

    Dumir, P.C.; Dube, G.P.; Joshi, S. [Applied Mechanics Dept., I.I.T. Delhi, New Delhi (India)

    2001-05-01

    Axisymmetric buckling and postbuckling analysis is presented for a moderately thick, laminated shallow conical cap under static transverse load. Marguerre-type, first-order shear deformation shallow-shell theory is formulated in terms of transverse deflection w, the rotation {psi} of the normal to the midsurface and the stress function {phi}. The governing equations are solved by the orthogonal point-collocation method. Clamped conical caps and simple supports with movable and immovable edge conditions are considered. Typical numerical results are presented, illustrating the effect of various parameters. The dependence of the effect of the shear deformation on the thickness parameter, boundary conditions, ratio of Young's moduli and cap height is investigated. (orig.)

  17. Axisymmetric buckling of laminated thick annular spherical cap

    Science.gov (United States)

    Dumir, P. C.; Dube, G. P.; Mallick, A.

    2005-03-01

    Axisymmetric buckling analysis is presented for moderately thick laminated shallow annular spherical cap under transverse load. Buckling under central ring load and uniformly distributed transverse load, applied statically or as a step function load is considered. The central circular opening is either free or plugged by a rigid central mass or reinforced by a rigid ring. Annular spherical caps have been analysed for clamped and simple supports with movable and immovable inplane edge conditions. The governing equations of the Marguerre-type, first order shear deformation shallow shell theory (FSDT), formulated in terms of transverse deflection w, the rotation ψ of the normal to the midsurface and the stress function Φ, are solved by the orthogonal point collocation method. Typical numerical results for static and dynamic buckling loads for FSDT are compared with the classical lamination theory and the dependence of the effect of the shear deformation on the thickness parameter for various boundary conditions is investigated.

  18. QUASILOCAL ENERGY FOR STATIONARY AXISYMMETRIC EMDA BLACK HOLE

    Institute of Scientific and Technical Information of China (English)

    WANG SHI-LIANG; JING JI-LIANG

    2001-01-01

    By using Brown-York quasilocal energy theory we calculate the quasilocal energy of a stationary axisymmetic EMDA black hole and explore the universality of Martinez's conjecture in string theory. We show that the energy is positive and monotonically decreases to the ADM mass at spatial infinity, and the Martinez's conjecture, the Brown York quasilocal energy at the outer horizon reduces to twice its irreducible mass, is still valid for stationary axisymmetric EMDA black hole. From the result we also find that the Kerr-Sen spacetime keeps up with Martinez's conjecture. This is different from the Bose-Naing result that the quasilocal energy of the Kerr Sen spacetime does not approach the Martinez's conjecture.

  19. Axisymmetric equilibria with pressure anisotropy and plasma flow

    CERN Document Server

    Evangelias, Achilleas

    2016-01-01

    In this Master thesis we investigate the influence of pressure anisotropy and incompressible flow of arbitrary direction on the equilibrium properties of magnetically confined, axisymmetric toroidal plasmas. The main novel contribution is the derivation of a pertinent generalised Grad-Shafranov equation. This equation includes six free surface functions and recovers known Grad-Shafranov-like equations in the literature as well as the usual static, isotropic one. The form of the generalised equation indicates that pressure anisotropy and flow act additively on equilibrium. In addition, two sets of analytical solutions, an extended Solovev one with a plasma reaching the separatrix and an extended Hernegger-Maschke one for a plasma surrounded by a fixed boundary possessing an X-point, are constructed, particularly in relevance to the ITER and NSTX tokamaks. Furthermore, the impacts both of pressure anisotropy, through an anisotropy function assumed to be uniform on the magnetic surfaces, and plasma flow, via the...

  20. Causal structure of d = 5 vacua and axisymmetric spacetimes

    Energy Technology Data Exchange (ETDEWEB)

    Fiol, Bartomeu; Hofman, Christiaan E-mail: christiaan.hofman@weizmann.ac.il; Lozano-Tellechea, Ernesto

    2004-02-01

    We study the structure of closed timelike curves (CTCs) for the near horizon limit of the five dimensional BMPV black hole, in its overrotating regime. We argue that Bousso's holographic screens are inside the chronologically safe region, extending a similar observation of Boyda et al hep-th/0212087 for Goedel type solutions. We then extend this result to quite generic axisymmetric spacetimes with CTCs, showing that causal geodesics can't escape the chronologically safe region. As a spin-off of our results, we fill a gap in the identification of all maximally supersymmetric solutions of minimal five dimensional supergravity, bringing this problem to a full conclusion. (author)

  1. Ideal, steady-state, axisymmetric magnetohydrodynamic equations with flow

    International Nuclear Information System (INIS)

    The motivation of this study is to gain additional understanding of the effect of rotation on the equilibrium of a plasma. The axisymmetric equilibria of ideal magnetohydrodynamics (MHD) with flow have been studied numerically and analytically. A general discussion is provided of previous work on plasmas with flow and comparisons are made to the static model. A variational principle has been derived for the two dimensional problem with comments as to appropriate boundary conditions. An inverse aspect ratio expansion has been used for a study of the toroidal flow equation for both low- and high-β. The inverse aspect ratio expansion has also been used for a study of equations with both poloidal and toroidal flow. An overview is provided of the adaptive finite-difference code which was developed to solve the full equations. (FI)

  2. Development of Compact Quasi-Axisymmetric Stellarator Reactor Configurations

    International Nuclear Information System (INIS)

    We have started to examine the reactor potential of quasi-axisymmetric (QA) stellarators with an integrated approach that includes systems evaluation, engineering considerations, and plasma and coil optimizations. In this paper, we summarize the progress made so far in developing QA configurations with reduced alpha losses while retaining good MHD stability properties. The minimization of alpha losses is achieved by directly targeting the collisionless orbits to prolong the average resident times. Configurations with an overall energy loss rate of ∼10% or less, including collisional contributions, have been found. To allow remotely maintaining coils and machine components in a reactor environment, there is a desire to simplify to the extent possible the coil design. To this end, finding a configuration that is optimized not only for the alpha confinement and MHD stability but also for the good coil and reactor performance, remains to be a challenging task

  3. Modular Coils and Plasma Configurations for Quasi-axisymmetric Stellarators

    Energy Technology Data Exchange (ETDEWEB)

    L.P. Ku and A.H. Boozer

    2010-09-10

    Characteristics of modular coils for quasi-axisymmetric stellarators that are related to the plasma aspect ratio, number of field periods and rotational transform have been examined systematically. It is observed that, for a given plasma aspect ratio, the coil complexity tends to increase with the increased number of field periods. For a given number of field periods, the toroidal excursion of coil winding is reduced as the plasma aspect ratio is increased. It is also clear that the larger the coil-plasma separation is, the more complex the coils become. It is further demonstrated that it is possible to use other types of coils to complement modular coils to improve both the physics and the modular coil characteristics.

  4. Fluidic Control of Aerodynamic Forces on an Axisymmetric Body

    Science.gov (United States)

    Abramson, Philip; Vukasinovic, Bojan; Glezer, Ari

    2007-11-01

    The aerodynamic forces and moments on a wind tunnel model of an axisymmetric bluff body are modified by induced local vectoring of the separated base flow. Control is effected by an array of four integrated aft-facing synthetic jets that emanate from narrow, azimuthally-segmented slots, equally distributed around the perimeter of the circular tail end within a small backward facing step that extends into a Coanda surface. The model is suspended in the wind tunnel by eight thin wires for minimal support interference with the wake. Fluidic actuation results in a localized, segmented vectoring of the separated base flow along the rear Coanda surface and induces asymmetric aerodynamic forces and moments to effect maneuvering during flight. The aerodynamic effects associated with quasi-steady and transitory differential, asymmetric activation of the Coanda effect are characterized using direct force and PIV measurements.

  5. Non-Radial Oscillations in an Axisymmetric MHD Incompressible Fluid

    Indian Academy of Sciences (India)

    A. Satya Narayanan

    2000-09-01

    It is well known from Helioseismology that the Sun exhibits oscillations on a global scale, most of which are non-radial in nature. These oscillations help us to get a clear picture of the internal structure of the Sun as has been demonstrated by the theoretical and observational (such as GONG) studies. In this study we formulate the linearised equations of motion for non-radial oscillations by perturbing the MHD equilibrium solution for an axisymmetric incompressible fluid. The fluid motion and the magnetic field are expressed as scalars , , and , respectively. In deriving the exact solution for the equilibrium state, we neglect the contribution due to meridional circulation. The perturbed quantities *, *, *, * are written in terms of orthogonal polynomials. A special case of the above formulation and its stability is discussed.

  6. Cellular blebs: pressure-driven, axisymmetric, membrane protrusions

    KAUST Repository

    Woolley, Thomas E.

    2013-07-16

    Blebs are cellular protrusions that are used by cells for multiple purposes including locomotion. A mechanical model for the problem of pressure-driven blebs based on force and moment balances of an axisymmetric shell model is proposed. The formation of a bleb is initiated by weakening the shell over a small region, and the deformation of the cellular membrane from the cortex is obtained during inflation. However, simply weakening the shell leads to an area increase of more than 4 %, which is physically unrealistic. Thus, the model is extended to include a reconfiguration process that allows large blebs to form with small increases in area. It is observed that both geometric and biomechanical constraints are important in this process. In particular, it is shown that although blebs are driven by a pressure difference across the cellular membrane, it is not the limiting factor in determining bleb size. © 2013 Springer-Verlag Berlin Heidelberg.

  7. Finite Axisymmetric Charged Dust Disks Sources for Conformastatic Spacetimes

    Science.gov (United States)

    González, Guillermo A.; Gutiérrez-Piñeres, Antonio C.; Ospina, Paolo A.

    2009-05-01

    An infinite family of finite axisymmetric charged dust disks is presented. The disks are obtained by solving the Einstein-Maxwell equations for conformastatic spacetimes by assuming a functional dependency between the time-like component of the electromagnetic potential and the metric potential in terms of a solution of the Laplace equation. We give solutions to the Einstein-Maxwell equations with disk sources of finite extension in which the charge density is proportional to the energy surface density. We apply the well-know ``inverse'' approach to the gravitational potential representing finite thin disks given by Gonzalez and Reina to generate conformastatic charged dust thin discs. Exact examples of conformastatic metrics with disk sources are worked out in full.

  8. Finite Axisymmetric Charged Dust Disks Sources for Conformastatic Spacetimes

    CERN Document Server

    González, Guillermo A; Ospina, Paolo A; 10.1063/1.3141293

    2009-01-01

    An infinite family of finite axisymmetric charged dust disks is presented. The disks are obtained by solving the Einstein-Maxwell equations for conformastatic spacetimes by assuming a functional dependency between the time-like component of the electromagnetic potential and the metric potential in terms of a solution of the Laplace equation. We give solutions to the Einstein-Maxwell equations with disk sources of finite extension in which the charge density is proportional to the energy surface density. We apply the well-know "inverse" approach to the gravitational potential representing finite thin disks given by Gonzalez and Reina to generate conformastatic charged dust thin discs. Exact examples of conformastatic metrics with disk sources are worked out in full.

  9. Nonlinear electromagnetic gyrokinetic equations for rotating axisymmetric plasmas

    International Nuclear Information System (INIS)

    The influence of sheared equilibrium flows on the confinement properties of tokamak plasmas is a topic of much current interest. A proper theoretical foundation for the systematic kinetic analysis of this important problem has been provided here by presented the derivation of a set of nonlinear electromagnetic gyrokinetic equations applicable to low frequency microinstabilities in a rotating axisymmetric plasma. The subsonic rotation velocity considered is in the direction of symmetry with the angular rotation frequency being a function of the equilibrium magnetic flux surface. In accordance with experimental observations, the rotation profile is chosen to scale with the ion temperature. The results obtained represent the shear flow generalization of the earlier analysis by Frieman and Chen where such flows were not taken into account. In order to make it readily applicable to gyrokinetic particle simulations, this set of equations is cast in a phase-space-conserving continuity equation form

  10. Mirror-Symmetric Matrices and Their Application

    Institute of Scientific and Technical Information of China (English)

    李国林; 冯正和

    2002-01-01

    The well-known centrosymmetric matrices correctly reflect mirror-symmetry with no component or only one component on the mirror plane. Mirror-symmetric matrices defined in this paper can represent mirror-symmetric structures with various components on the mirror plane. Some basic properties of mirror-symmetric matrices were studied and applied to interconnection analysis. A generalized odd/even-mode decomposition scheme was developed based on the mirror reflection relationship for mirror-symmetric multiconductor transmission lines (MTLs). The per-unit-length (PUL) impedance matrix Z and admittance matrix Y can be divided into odd-mode and even-mode PUL matrices. Thus the order of the MTL system is reduced from n to k and k+p, where p(≥0)is the conductor number on the mirror plane. The analysis of mirror-symmetric matrices is related to the theory of symmetric group, which is the most effective tool for the study of symmetry.

  11. The characterization of tandem and corrugated wings

    Science.gov (United States)

    Lian, Yongsheng; Broering, Timothy; Hord, Kyle; Prater, Russell

    2014-02-01

    Dragonfly wings have two distinct features: a tandem configuration and wing corrugation. Both features have been extensively studied with the aim to understand the superior flight performance of dragonflies. In this paper we review recent development of tandem and corrugated wing aerodynamics. With regards to the tandem configuration, this review will focus on wing/wing and wing/vortex interactions at different flapping modes and wing spacing. In addition, the aerodynamics of tandem wings under gusty conditions will be reviewed and compared with isolated wings to demonstrate the gust resistance characteristics of flapping wings. Regarding corrugated wings, we review their structural and aerodynamic characteristics.

  12. Manufacturing Large Membrane Mirrors at Low Cost

    Science.gov (United States)

    2007-01-01

    Relatively inexpensive processes have been developed for manufacturing lightweight, wide-aperture mirrors that consist mainly of reflectively coated, edge-supported polyimide membranes. The polyimide and other materials in these mirrors can withstand the environment of outer space, and the mirrors have other characteristics that make them attractive for use on Earth as well as in outer space: With respect to the smoothness of their surfaces and the accuracy with which they retain their shapes, these mirrors approach the optical quality of heavier, more expensive conventional mirrors. Unlike conventional mirrors, these mirrors can be stowed compactly and later deployed to their full sizes. In typical cases, deployment would be effected by inflation. Potential terrestrial and outer-space applications for these mirrors include large astronomical telescopes, solar concentrators for generating electric power and thermal power, and microwave reflectors for communication, radar, and short-distance transmission of electric power. The relatively low cost of manufacturing these mirrors stems, in part, from the use of inexpensive tooling. Unlike in the manufacture of conventional mirrors, there is no need for mandrels or molds that have highly precise surface figures and highly polished surfaces. The surface smoothness is an inherent property of a polyimide film. The shaped area of the film is never placed in contact with a mold or mandrel surface: Instead the shape of a mirror is determined by a combination of (1) the shape of a fixture that holds the film around its edge and (2) control of manufacturing- process parameters. In a demonstration of this manufacturing concept, spherical mirrors having aperture diameters of 0.5 and 1.0 m were fabricated from polyimide films having thicknesses ranging from <20 m to 150 m. These mirrors have been found to maintain their preformed shapes following deployment.

  13. Technology demonstration report for the Mirror Fusion Test Facility (MFTF-B)

    International Nuclear Information System (INIS)

    This report describes the activities of the Mirror Fusion Test Facility (MFTF) Technology Demonstration Program during January and February 1982. It also documents the systems test, which verified all major technology and design objectives of the superconducting ying-yang magnet, vessel, and external vacuum, cryogenic, local control, instrumentation, and supervisory control and diagnostic systems. Because of this program, work on the design and construction of the tandem version of MFTF-B (axicell) is now proceeding with much greater design confidence and lower risks

  14. User's manual for the FLORA equilibrium and stability code

    International Nuclear Information System (INIS)

    This document provides a user's guide to the content and use of the two-dimensional axisymmetric equilibrium and stability code FLORA. FLORA addresses the low-frequency MHD stability of long-thin axisymmetric tandem mirror systems with finite pressure and finite-larmor-radius effects. FLORA solves an initial-value problem for interchange, rotational, and ballooning stability

  15. The ''mirrortron''. An application of mirror physics principles to particle accelerators

    International Nuclear Information System (INIS)

    An important aspect of fusion research is understanding the generation of electrical potentials through collective effects. Such potentials arise in all confinement systems, and play an essential role in the tandem mirror. This report addresses a related question: Could collective effects be employed within mirror-confined plasmas to generate very high potentials? If such is the case new types of particle accelerators might be developed for use in high energy research or in beam-driven inertial fusion systems. Concepts for using collective effects for particle acceleration date back several decades. Such concepts offer the promise of very high electric fields, but share a common problem: how to achieve precise control over the spatial and temporal variation of these potentials. Here this problem is to be solved by exploiting plasma quasineutrality in association with a transient magnetic field and ion inertial effects to create the potentials and to effect the required degree of control. The idea involves three elements: (1) a solenoidal ''dc'' magnetic field bounded at each end by moderate-height mirrors. (2) A low density (--10/sup 11/ cm/sup -3/) hot electron plasma. (3) A short oil located midway between the mirrors and capable of being pulsed to maximum field in --10 ms. This coil, segmented azimuthally to reduce voltage-handling problems, could use pulse technology such as that developed for the Livermore ATA accelerator

  16. Standard specification for silvered flat glass mirror

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This specification covers the requirements for silvered flat glass mirrors of rectangular shape supplied as cut sizes, stock sheets or as lehr ends and to which no further processing (such as edgework or other fabrication) has been done. 1.2 This specification covers the quality requirements of silvered annealed monolithic clear and tinted flat glass mirrors up to 6 mm (¼ in.) thick. The mirrors are intended to be used indoors for mirror glazing, for components of decorative accessories or for similar uses. 1.3 This specification does not address safety glazing materials nor requirements for mirror applications. Consult model building codes and other applicable standards for safety glazing applications. 1.4 Mirrors covered in this specification are not intended for use in environments where high humidity or airborne corrosion promoters, or both, are consistently present (such as swimming pool areas, ocean-going vessels, chemical laboratories and other corrosive environments). 1.5 The dimensional val...

  17. Mirror Development for the Cherenkov Telescope Array

    CERN Document Server

    Förster, A; Baba, H; Bähr, J; Bonardi, A; Bonnoli, G; Brun, P; Canestrari, R; Chadwick, P; Chikawa, M; Carton, P -H; De Souza, V; Dipold, J; Doro, M; Durand, D; Dyrda, M; Giro, E; Glicenstein, J -F; Hanabata, Y; Hayashida, M; Hrabovski, M; Jeanney, C; Kagaya, M; Katagiri, H; Lessio, L; MANDAT, D; Mariotti, M; Medina, C; Michałowski, J; Micolon, P; Nakajima, D; Niemiec, J; Nozato, A; Palatka, M; Pareschi, G; Pech, M; Peyaud, B; Pühlhofer, G; Rataj, M; Rodeghiero, G; Rojas, G; Rousselle, J; Sakonaka, R; Schovanek, P; Seweryn, K; Schultz, C; Shu, S; Stinzing, F; Stodulski, M; Teshima, M; Travniczek, P; Van Eldik, C; Vassiliev, V; Wiśniewski, Ł; Wörnlein, A; Yoshida, T

    2013-01-01

    The Cherenkov Telescope Array (CTA) is a planned observatory for very-high energy gamma-ray astronomy. It will consist of several tens of telescopes of different sizes, with a total mirror area of up to 10,000 square meters. Most mirrors of current installations are either polished glass mirrors or diamond-turned aluminium mirrors, both labour intensive technologies. For CTA, several new technologies for a fast and cost-efficient production of light-weight and reliable mirror substrates have been developed and industrial pre-production has started for most of them. In addition, new or improved aluminium-based and dielectric surface coatings have been developed to increase the reflectance over the lifetime of the mirrors compared to those of current Cherenkov telescope instruments.

  18. Reflectivity-modulated grating-mirror

    DEFF Research Database (Denmark)

    2012-01-01

    The invention relates to vertical cavity lasers (VCL) incorporating a reflectivity-modulated grating mirror (1) for modulating the laser output. A cavity is formed by a bottom mirror (4), an active region (3), and an outcoupling top grating mirror (1) formed by a periodic refractive index grating...... advantage of lower power consumption at high modulation speeds.......The invention relates to vertical cavity lasers (VCL) incorporating a reflectivity-modulated grating mirror (1) for modulating the laser output. A cavity is formed by a bottom mirror (4), an active region (3), and an outcoupling top grating mirror (1) formed by a periodic refractive index grating...... region in a layer structure comprising a p- and a n-doped semiconductor layer with an electrooptic material layer (12) arranged there between. The grating region comprises a grating structure formed by periodic perforations to change the refractive index periodically in directions normal to the...

  19. Novel unimorph adaptive mirrors for astronomy applications

    Science.gov (United States)

    Rausch, Peter; Verpoort, Sven; Wittrock, Ulrich

    2012-07-01

    We have developed a new type of unimorph deformable mirror for the correction of low-order Zernike modes. The mirror features a clear aperture of 50 mm combined with large peak-to-valley amplitudes of up to 35 μm. Newly developed fabrication processes allow the use of prefabricated, coated, super-polished glass substrates. The mirror's unique features suggest the use in several astronomical applications like the compensation of atmospheric aberrations seen by laser beacons and the use in woofer-tweeter systems. Additionally, the design enables an efficient correction of the inevitable wave-front error imposed by the floppy structure of primary mirrors in future large space telescopes. We have modeled the mirror by using analytical as well as finite element models. We will present design, key features and manufacturing steps of the deformable mirror.

  20. Effects of large-scale non-axisymmetric perturbations in the mean-field solar dynamo

    CERN Document Server

    Pipin, V V

    2015-01-01

    We explore a response of the non-linear non-axisymmetric mean-field solar dynamo model to the shallow non-axisymmetric perturbations with the strength of 1G. The amplitude of the non-axisymmetric field depends on the initial condition, helicity conservation, the depth of perturbation. It is found that perturbation which is anchored at the 0.9R have a profound effect and it produce the transient magnetic cycle of the axisymmetric magnetic field if it is initiated at the growing phase of the cycle. The non-symmetric about equator perturbation results the hemispheric asymmetry of the magnetic activity. The evolution of the axisymmetric and non-axisymmetric field depends on how well the magnetic helicity is conserved. In the range of Rm=10^{4-6} the evolution returns to the normal course in the next cycle and the non-axisymmetric field is generated due to non-linear alpha-effect and the magnetic buoyancy. In the stationary state of evolution the large-scale magnetic field demonstrate, the phenomena of the "active...

  1. The sea is your mirror

    OpenAIRE

    Parenthoen, Marc; Murie, Fred; Thery, Flavien

    2015-01-01

    The Sea Is Your Mirror is an artistic interactive experience where surface cerebral electromagnetic waves from a participant wearing an EEG sensor headset are depicted in real-time as ocean waves in an animated 3D environment. The aim of this article is to describe the sea wave model used for the sea state animation and how it is connected to the brain computer interface (BCI). The sea state is animated by the groupy choppy wave model that provides nonlinear sea states with wave groups and as...

  2. Spontaneous violation of mirror symmetry

    CERN Document Server

    Dyatlov, Igor T

    2015-01-01

    A symmetry violation model is considered for a system that can spontaneously choose between identical states which differ from each other only in weak properties (R-L). Such mirror symmetry allows reproduction of observed qualitative properties of quark and lepton mixing matrices. The lepton mixing matrix evidences in this case in favor of the inverse mass spectrum and the Dirac nature of SM neutrino. Notwithstanding the Dirac properties of neutrino, an exchange of lepton numbers such as $e^{-}+\\mu^{+}\\rightarrow e^{+}+\\mu^{-}$ is possible but with only leptons participating in the process.

  3. Beautiful Mirrors at the LHC

    OpenAIRE

    Kumar, Kunal; Shepherd, William; Tait, Tim M. P.; Vega-Morales, Roberto(Laboratoire de Physique Théorique, CNRS-UMR 8627, Université Paris-Sud 11, F-91405, Orsay Cedex, France)

    2010-01-01

    We explore the "Beautiful Mirrors" model, which aims to explain the measured value of $A^b_{FB}$, discrepant at the $2.9\\sigma$ level. This scenario introduces vector-like quarks which mix with the bottom, subtly affecting its coupling to the $Z$. The spectrum of the new particles consists of two bottom-like quarks and a charge -4/3 quark, all of which have electroweak interactions with the third generation. We explore the phenomenology and discovery reach for these new particles at the LHC, ...

  4. Deformable Mirrors Correct Optical Distortions

    Science.gov (United States)

    2010-01-01

    By combining the high sensitivity of space telescopes with revolutionary imaging technologies consisting primarily of adaptive optics, the Terrestrial Planet Finder is slated to have imaging power 100 times greater than the Hubble Space Telescope. To this end, Boston Micromachines Corporation, of Cambridge, Massachusetts, received Small Business Innovation Research (SBIR) contracts from the Jet Propulsion Laboratory for space-based adaptive optical technology. The work resulted in a microelectromechanical systems (MEMS) deformable mirror (DM) called the Kilo-DM. The company now offers a full line of MEMS DMs, which are being used in observatories across the world, in laser communication, and microscopy.

  5. MIRROR THERAPY: A REVIEW OF EVIDENCES

    OpenAIRE

    Aishath Najiha; Jagatheesan Alagesan,; Vandana J. Rathod; Poongundran Paranthaman

    2015-01-01

    The aim of this review was to identify and summarize the existing evidences on mirror box therapy for the management of various musculoskeletal conditions. A systemic literature search was performed to identify studies concerning mirror therapy. The included journal articles were reviewed and assessed for its significance. Fifty one studies were identified and reviewed. Five different patient categories were studied: 24 studies focussed on mirror therapy after stroke, thirteen studies focusse...

  6. A framework for tropical mirror symmetry

    OpenAIRE

    Boehm, Janko

    2011-01-01

    Applying tropical geometry a framework for mirror symmetry, including a mirror construction for Calabi-Yau varieties, was proposed by the author. We discuss the conceptual foundations of this construction based on a natural mirror map identifying deformations and divisors. We show how the construction specializes to that by Batyrev for hypersurfaces and its generalization by Batyrev and Borisov to complete intersections. Based on an explicit example we comment on the implementation in the Mac...

  7. A framework for tropical mirror symmetry

    CERN Document Server

    Boehm, Janko

    2011-01-01

    Applying tropical geometry a framework for mirror symmetry, including a mirror construction for Calabi-Yau varieties, was proposed by the author. We discuss the conceptual foundations of this construction based on a natural mirror map identifying deformations and divisors. We show how the construction specializes to that by Batyrev for hypersurfaces and its generalization by Batyrev and Borisov to complete intersections. Based on an explicit example we comment on the implementation in the Macaulay2 package SRdeformations.

  8. Gravity and Mirror Gravity in Plebanski Formulation

    OpenAIRE

    Bennett, D. L.; Laperashvili, L. V.; Nielsen, H. B.; Tureanu, A.

    2012-01-01

    We present several theories of four-dimensional gravity in the Plebanski formulation, in which the tetrads and the connections are the independent dynamical variables. We consider the relation between different versions of gravitational theories: Einstenian, dual, 'mirror' gravities and gravity with torsion. According to Plebanski's assumption, our world, in which we live, is described by the self-dual left-handed gravity. We propose that if the Mirror World exists in Nature, then the 'mirror...

  9. Advanced Mirror System Demonstrator (AMSD) Risk Management

    Science.gov (United States)

    Byberg, Alicia; Russell, J. Kevin; Kaukler, Donna; Burdine, Robert V. (Technical Monitor)

    2002-01-01

    This paper will report risk issues associated with designing, manufacturing, and testing the Advanced Mirror System Demonstrator (AMSD). The Advanced Mirror System Demonstrator (AMSD) will be developed as a lightweight primary mirror system that can be produced at a low cost and with a short manufacturing schedule. This technology will add to the knowledge base for selection for the Next Generation Space Telescope (NGST), Space Based Laser (SBL), Research Laboratory mission (AFRL), and other government agency programs.

  10. Surface analysis and a novel application of carbon sheet pump in the GAMMA 10 tandem mirror

    International Nuclear Information System (INIS)

    Samples of carbon sheet pump (CSP) exposed to fast neutrals have been analyzed by using microscopic techniques in order to improve the performance of CSP and to examine the applicability of CSP to actual devices. It has been confirmed from the microscopic viewpoint for the first time that fast neutrals emitted from plasmas generated by the actual confinement device (GAMMA 10) are trapped by the C/C material. A numerical simulation is performed by means of the Monte Carlo simulation code TRIM (ver. TRVMC95) for the sake of the evaluation of the results obtained by elastic recoil detection technique. CSP has been newly applied to the shine-through beam dump of a neutral beam injector in order to test the pumping effect of CSP under the conditions of high heat and particle load (several MW/m2 and 2.5x1021 H/m2 s at the beam center, respectively). It also has been found from pressure-balance analysis that 80% of incident particles are trapped by CSP

  11. Tandem mirror hybrid reactor study (LLL Purchase Order 6887809 dated August 31, 1979)

    International Nuclear Information System (INIS)

    The results, bases, qualifications, and exclusions of the preconceptual cost estimate are presented below. This estimate is an order-of-magnitude assessment of the direct level POP Costs. The direct level cost consists of: (1) total cost of all materials forming the permanent part of the completed plant, and (2) total cost of all labor engaged in installing and erecting all materials forming the permanent part of the completed plant. A cost summary and a supporting breakdown of this estimate are shown

  12. The tandem mirror experiment upgrade (TMX-U) diagnostics data system

    International Nuclear Information System (INIS)

    The diagnostics data system on the TMX-U experiment is a general purpose system for handling acquisition, processing, archiving, interactive selection and retrieval, and graphical and tabular outputting of data for pulsed controlled thermonuclear reaction experiments. It routinely acquires and processes three MBytes of data per shot at an average shot rate of one per 8 minutes. The computer hardware consists of five CPUs in a star configuration with approximately 500 MBytes of disk storage at the central node, upon which all CPUs may read and write. The use of several CPUs in parallel increases computing power, while the use of eight disk drives in parallel increases disk speed. All processing, outputting, and acquisition are performed by program modules that allow chained operations, i.e., the inputs for a given task (program execution) are the output(s) of a previous task or tasks. Inputs may be any data-set on disk. Tasks for various shots may overlap so that high priority results are immediately available, while low priority results may backlog and catch up during lulls in experiment operation. Task selection is thus both data-availability and priority driven. It is done in a distributed fashion, independently by each of the five CPUs (not master-slave). A given task will run on any available, suitable CPU. CPU suitability is determined using a device resource control system. Program resource requirements, task definitions, task lists, etc., as well as permanent definitions of all archived data-set configurations and symbols are saved using a commercial data-base system and custom editor, which form a data-system ''notebook''. The actual data are held in a custom data base with a hybrid relational/hierarchical form. Data-set formats are selectable from a rich, yet standardized set that can accommodate a large variety of acquired or calculated data

  13. Interfacing the tandem mirror reactor to the sulfur-iodine process for hydrogen production

    International Nuclear Information System (INIS)

    The blanket is linked to the H2SO4 vaporization units and SO3 decomposition reactor with either sodium or helium. The engineering and safety problems associated with these choices are discussed. This H2SO4 step uses about 90% of the TMR heat and is best close-coupled to the nuclear island. The rest of the process we propose to be driven by steam and does not require close-coupling. The sodium loop coupling seems to be preferable at this time. We can operate with a blanket around 1200 K and the SO3 decomposer around 1050 K. This configuration offers double-barrier protection between Li-Na and the SO3 process gases. Heat pipes offer an attractive alternate to provide an additional barrier, added modularity for increased reliability, and tritium concentration and isolation operations with very little thermal penalty

  14. Design and construction of the vacuum vessel for the tandem Mirror Fusion Test Facility

    International Nuclear Information System (INIS)

    We have designed the MFTF-B vacuum vessel both to maintain the required vacuum environment and to structurally support the 42 superconducting magnets plus auxiliary internal and external equipment. The design calculations were greatly aided by computer models, which also speeded our redesign effort when the machine configuration was changed to the Axicelll MFTF-B this past year. Our field construction and erection effort should meet the July 1984 completion date for the vacuum vessel

  15. Alpha particle density and energy distributions in tandem mirrors using Monte-Carlo techniques

    International Nuclear Information System (INIS)

    We have simulated the alpha thermalization process using a Monte-Carlo technique, in which the alpha guiding center is followed between simulated collisions and Spitzer's collision model is used for the alpha-plasma interaction. Monte-Carlo techniques are used to determine the alpha radial birth position, the alpha particle position at a collision, and the angle scatter and dispersion at a collision. The plasma is modeled as a hot reacting core, surrounded by a cold halo plasma (T approx.50 eV). Alpha orbits that intersect the halo lose 90% of their energy to the halo electrons because of the halo drag, which is ten times greater than the drag in the core. The uneven drag across the alpha orbit also produces an outward, radial, guiding center drift. This drag drift is dependent on the plasma density and temperature radial profiles. We have modeled these profiles and have specifically studied a single-scale-length model, in which the density scale length (r/sub pD/) equals the temperature scale length (r/sub pT/), and a two-scale-length model, in which r/sub pD//r/sub pT/ = 1.1

  16. Plasma-surface interactions in large tandem mirror devices - MFTF-B

    International Nuclear Information System (INIS)

    Present experiments on TMX-U and modeling of MFTF-B indicate that plasma-surface interactions can be controlled in MFTF-B. The MFTF-B configuration uses a hot electron population created by ECRH and a sloshing-ion population created by neutral beams in the thermal barrier region to create a potential that confines the central cell ions. Neutral beams and ICRH are used to heat the central cell ions. Plasma-surface interactions can be minimized at radial surfaces by control of the axial confinement of the edge plasma. The thermal barrier configuration is sensitive to the background neutral density, and requires low wall reflux and efficient shielding by the edge plasma. Glow discharge cleaning, titanium gettering, and control of the gas from neutral beams will be used to provide wall conditioning and to reduce the background gas pressure. The shielding efficiency of the plasma edge has been modeled in MFTF-B by comparing computer codes with current experimental measurements. In addition, it is very important to reduce high-energy neutral-beam-injected impurities; this is accomplished by using gettering or magnetic separation in the injector systems. Plasma-edge scrapers, diverter-like devices, and direct-conversion equipment will be located in the end region. Major disruptions are not anticipated. Finally, MFTF-B will also test some technological issues that are revelant to reactors: superconducting magnet systems and nearly steady-state (30-s) operation

  17. Special topics reports for the reference tandem mirror fusion breeder. Volume 5. Neutronic issues and optimization

    International Nuclear Information System (INIS)

    More rigorous nuclear analysis, including the treatment of resonance self-shielding effects coupled with an optimization procedure, has resulted in improved performance of the Be/Li/Th blanket. Net U-233 breeding ratio has increased 36% (to 0.84) while at a U/Th ratio of 0.25 a/o energy multiplication has increased 12% (to 2.1) compared with earlier results

  18. Plasma-surface interactions in large tandem mirror devices-MFTF-B

    International Nuclear Information System (INIS)

    Present experiments on TMX-U and modeling of MFTF-B indicate that plasma-surface interactions can be controlled in MFTF-B. The MFTF-B configuration uses a hot electron population created by ECRH and a sloshing-ion population created by neutral beams in the thermal barrier region to create a potential that confines the central cell ions. Neutral beams and ICRH are used to heat the central cell ions. Plasma-surface interactions can be minimized at radial surfaces by control of the axial confinement of the edge plasma. The thermal barrier configuration is sensitive to the background neutral density, and requires low wall reflux and efficient shielding by the edge plasma. Glow discharge cleaning, titanium gettering, and control of the gas from neutral beams will be used to provide wall conditioning and to reduce the background gas pressure. The shielding efficiency of the plasma edge has been modeled in MFTF-B by comparing computer codes with current experimental measurements. In addition, it is very important to reduce high-energy neutral-beam-injected impurities; this is accomplished by using gettering or magnetic separation in the injector systems. Plasma-edge scrapers, diverter-like devices, and direct-conversion equipment will be located in the end region. Major disruptions are not anticipated. Finally, MFTF-B will also test some technological issues that are relevant to reactors: superconducting magnet systems and nearly steady-state (30 s) operation. (orig.)

  19. Fluctuation suppression during the ECH induced potential formation in the tandem mirror GAMMA 10

    International Nuclear Information System (INIS)

    The suppression of the potential fluctuation was clearly observed during the radial potential profile change and positive electric fields driven by electron cyclotron heating. The particle flux evaluated from the phase difference between the potential and density fluctuations measured by a gold neutral beam probe showed the radial outward flux and its correlation with the decrease in the stored energy. When flux is suppressed by the potential formation, the plasma stored energy increases quickly. These indicate that the observed fluctuations are the one of the source of the anomalous radial transport and the radial profile of the potential is one of the keys to control plasma transport. (author)

  20. Tandem mirror hybrid reactor study (LLL Purchase Order 3323609 dated October 20, 1978)

    International Nuclear Information System (INIS)

    In any nuclear power plant, reactor design and performance are the major determining and driving factors of the plant economic and technical viability. However, the balance-of-plant (BOP) - which includes heat transport and energy conversion systems, plant auxiliary systems, plant electrical system, and structures and facilities - has a major effect on the plant economics. In fact, the BOP can account for as much as 70 to 85 percent of the total plant capital cost and therefore will have a significant impact upon the economic viability of the plant. Further, decisions made in the reactor design can have significant impact on the BOP design. A preconceptual BOP design and an order-of-magnitude cost estimate were developed for the helium cooled TMHR and are described