Science.gov

Sample records for poloidal field system

  1. Equilibrium modeling of the TFCX poloidal field coil system

    SciTech Connect

    Strickler, D.J.; Miller, J.B.; Rothe, K.E.; Peng, Y.K.M.

    1984-04-01

    The Toroidal Fusion Core Experiment (TFCX) isproposed to be an ignition device with a low safety factor (q approx. = 2.0), rf or rf-assisted startup, long inductive burn pulse (approx. 300 s), and an elongated plasma cross section (kappa = 1.6) with moderate triangularity (delta = 0.3). System trade studies have been carried out to assist in choosing an appropriate candidate for TFCX conceptual design. This report describes an important element in these system studies - the magnetohydrodynamic (MHD) equilibrium modeling of the TFCX poloidal field (PF) coil system and its impact on the choice of machine size. Reference design points for the all-super-conducting toroidal field (TF) coil (TFCX-S) and hybrid (TFCX-H) options are presented that satisfy given PF system criteria, including volt-second requirements during burn, mechanical configuration constraints, maximum field constraints at the superconducting PF coils, and plasma shape parameters. Poloidal coil current waveforms for the TFCX-S and TFCX-H reference designs consistent with the equilibrium requirements of the plasma startup, heating, and burn phases of a typical discharge scenario are calculated. Finally, a possible option for quasi-steady-state operation is discussed.

  2. Performance of current measurement system in poloidal field power supply for Experimental Advanced Superconducting Tokamak

    NASA Astrophysics Data System (ADS)

    Liu, D. M.; Li, J.; Wan, B. N.; Lu, Z.; Wang, L. S.; Jiang, L.; Lu, C. H.; Huang, J.

    2016-11-01

    As one of the core subsystems of the Experimental Advanced Superconducting Tokamak (EAST), the poloidal field power system supplies energy to EAST's superconducting coils. To measure the converter current in the poloidal field power system, a current measurement system has been designed. The proposed measurement system is composed of a Rogowski coil and a newly designed integrator. The results of the resistor-inductor-capacitor discharge test and the converter equal current test show that the current measurement system provides good reliability and stability, and the maximum error of the proposed system is less than 1%.

  3. Performance of current measurement system in poloidal field power supply for Experimental Advanced Superconducting Tokamak.

    PubMed

    Liu, D M; Li, J; Wan, B N; Lu, Z; Wang, L S; Jiang, L; Lu, C H; Huang, J

    2016-11-01

    As one of the core subsystems of the Experimental Advanced Superconducting Tokamak (EAST), the poloidal field power system supplies energy to EAST's superconducting coils. To measure the converter current in the poloidal field power system, a current measurement system has been designed. The proposed measurement system is composed of a Rogowski coil and a newly designed integrator. The results of the resistor-inductor-capacitor discharge test and the converter equal current test show that the current measurement system provides good reliability and stability, and the maximum error of the proposed system is less than 1%.

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

    DOEpatents

    Marcus, Frederick B.

    1978-01-01

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

  5. Tokamak poloidal field systems. Progress report, January 1-December 31, 1979

    SciTech Connect

    Rogers, J.D.

    1980-05-01

    Work is reported on the development of superconducting tokamak poloidal field systems (TPFS). Progress is discussed on the design of a 20 MJ, 50 kA, 7.5 T superconducting pulsed energy storage coil operated in a 1 to 2 s bipolar mode from +7.5 T to -7.5 T in 1982. Conductor development for the coil is presented. A facility that uses a traction motor energy transfer system to test coils in the 20 to 100 MJ energy range is discussed. Current interrupter development and testing for protection and energy transfer circuits are also presented. The 400 kJ METS coil test preparation is under way.

  6. Tokamak poloidal-field systems. Progress report, January 1-December 31, 1981

    SciTech Connect

    Rogers, J.D.

    1982-03-01

    Work on the superconducting tokamak poloidal field system (TPFS) program is being redirected. The development of the 20 MJ, 50 kA, 7.5 T superconducting programmed energy storage coil is being terminated. The superconductor for the 20 MJ coil is being processed only to an intermediate state, and manufacture of the epoxy fiberglass dewar is being stopped. Further, development of the TPFS test facility is in abeyance. Change in program emphasis arises from prospective rf plasma current driven or beam heated tokamaks with programmed coil characteristics for the poloidal field being different from those to have been simulated by the 20 MJ coil and from budgetary constraints. Work is reported on the development of the coil, conductor, nonconducting dewar, and test facility to the recent time when the program change was instigated. Work in support of the Large Coil Test Facility (LCTF) and the Fusion Engineering Design (FED) Center is given. Analysis of the experiments on the 400 kJ METS coil test was completed.

  7. Tokamak poloidal field systems. Progress report, January 1-December 31, 1980

    SciTech Connect

    Rogers, J.D.

    1981-03-01

    Work is reported on the development of superconducting tokamak poloidal field system (TPFS) program. Progress is discussed on the design of the 20 MJ, 50 kA, 7.5 T superconducting pulsed energy storage coil to be operated in a bipolar mode from +7.5 T to -7.5 T in an energy transfer period of 1.5 to 5 s in 1982 followed by extensive cyclic testing. The facility to conduct the tests uses a traction motor energy transfer system and a nonconducting dewar. Status of the hardware development for the TPFS program is presented. Current interrupter development and testing for protection and energy transfer circuits are also presented. The 400 kJ METS coil test results are given.

  8. POLOIDAL MAGNETIC FIELD MEASUREMENTS AND ANALYSIS WITH THE DIII-D LIBEAM SYSTEM

    SciTech Connect

    D.M. THOMAS

    2002-08-01

    For over thirty years, neutral lithium beams have been employed as a localized, noninvasive diagnostic on a variety of plasma experiments worldwide, providing a number of key physics measurements. On DIII-D the LIBEAM diagnostic has been designed to provide precise measurements of the local poloidal magnetic field in the edge region, a parameter of basic importance to understanding the stability of high performance tokamaks. We utilize the Zeeman splitting and known polarization characteristics of the collisionally excited 670.8 nm Li resonance line to interpret local magnetic field components viewed using a closely packed ({Delta}R {approx} 5 mm) array of 32 viewchords. A dual photoelastic modulator/linear polarizer combination serves to amplitude modulate the light in exact correspondence to its input polarization state. Subsequent narrowband spectral filtering using etalons and standard interference filters is used to isolate one of the three Zeeman components, and the polarization state of that component is recovered using a PC-based, multichannel digital lock-in detection system. Edge magnetic pitch angle profiles for a variety of shots have been reconstructed using a small number of chords and detailed analysis of the lockin and d.c. signal levels. Present system performance appears to be limited by etalon performance as well as various broadening mechanisms in the beam that tend to decrease the polarization fraction in the observed component. A careful analysis of this effect and some strategies for improving the measured polarization will be presented.

  9. Poloidal and toroidal fields in geomagnetic field modeling

    NASA Astrophysics Data System (ADS)

    Backus, G.

    1986-02-01

    The application of surface operator theory to poloidal and toroidal fields in geomagnetic field modeling is described. Surface operators are obtained for the dimensionless surface gradient; the dimensionless surface curl; the dimensionless surface Laplacian, as well as for the Funk-Hecke operators, integral operators, and axisymmetric kernels. Methods are given for interpreting satellite measurements of the geomagnetic field B, assuming B is can vary significantly and rapidly with time, and there are electric fields in the sample. Approximation schemes for ionospheric currents are also described.

  10. The reversed-field pinch as a poloidal-field-dominated, compact, high-power-density fusion system

    SciTech Connect

    Krakowski, R.A.

    1988-01-01

    This paper discusses the feasibility of reversed-field pinch devices as future thermonuclear reactors. Safety, cost, ion temperatures, Lawson numbers, and power densities are reviewed for these types of devices. 12 refs., 2 figs., 1 tab. (LSP)

  11. Toroidal and poloidal magnetic fields at Venus. Venus Express observations

    NASA Astrophysics Data System (ADS)

    Dubinin, E.; Fraenz, M.; Woch, J.; Zhang, T. L.; Wei, Y.; Fedorov, A.; Barabash, S.; Lundin, R.

    2013-10-01

    Magnetic field and plasma measurements carried out onboard Venus Express during solar minimum conditions suggest the existence of two kinds of magnetic field configuration in the Venusian ionosphere. We interpret these as the manifestation of two different types of generation mechanisms for the induced magnetosphere. A different magnetic field topology (toroidal and poloidal) arises if the induced currents are driven either by the solar wind motional electric field or by the Faraday electric field—a conducting ionosphere sees the magnetic field carried by solar wind as a time-varying field. At the dayside, both driving agents produce a similar draping pattern of the magnetic field. However, different magnetic field signatures inherent to both induction mechanisms appear at lower altitudes in the terminator region. The conditions at low solar EUV flux when the ionosphere of Venus becomes magnetized seem to be favorable to distinguish between two different types of the induced fields. We present cases of both types of the magnetic field topology. The cases when the effects of the Faraday induction become well noticeable are especially interesting since they provide us with an example of solar wind interaction with a tiny induced dipole field immersed into the ionosphere. Another interesting case when poloidal magnetic fields are evidently displayed is observed when the IMF vector is almost aligned with the solar wind velocity. In general case, both mechanisms of induction probably complement each other.

  12. Current density and poloidal magnetic field for toroidal elliptic plasmas with triangularity

    SciTech Connect

    Martin, P.; Haines, M.G.; Castro, E.

    2005-08-15

    Changes in the poloidal magnetic field around a tokamak magnetic surface due to different values of triangularity and ellipticity are analyzed in this paper. The treatment here presented allows the determination of the poloidal magnetic field from knowledge of the toroidal current density. Different profiles of these currents are studied. Improvements in the analytic forms of the magnetic surfaces have also been found. The treatment has been performed using a recent published system of coordinates. Suitable analytic equations have been used for the elliptic magnetic surfaces with triangularity and Shafranov shift.

  13. POLOIDAL MAGNETIC FIELD TOPOLOGY FOR TOKAMAKS WITH CURRENT HOLES

    SciTech Connect

    Puerta, Julio; Martin, Pablo; Castro, Enrique

    2009-07-26

    The appearance of hole currents in tokamaks seems to be very important in plasma confinement and on-set of instabilities, and this paper is devoted to study the topology changes of poloidal magnetic fields in tokamaks. In order to determine these fields different models for current profiles can be considered. It seems to us, that one of the best analytic descriptions is given by V. Yavorskij et al., which has been chosen for the calculations here performed. Suitable analytic equations for the family of magnetic field surfaces with triangularity and Shafranov shift are written down here. The topology of the magnetic field determines the amount of trapped particles in the generalized mirror type magnetic field configurations. Here it is found that the number of maximums and minimums of Bp depends mainly on triangularity, but the pattern is also depending of the existence or not of hole currents. Our calculations allow comparing the topology of configurations of similar parameters, but with and without whole currents. These differences are study for configurations with equal ellipticity but changing the triangularity parameters. Positive and negative triangularities are considered and compared between them.

  14. A method for estimating tokamak poloidal field coil currents which incorporates engineering constraints

    SciTech Connect

    Stewart, W.A.

    1990-05-01

    This thesis describes the development of a design tool for the poloidal field magnet system of a tokamak. Specifically, an existing program for determining the poloidal field coil currents has been modified to: support the general case of asymmetric equilibria and coil sets, determine the coil currents subject to constraints on the maximum values of those currents, and determine the coil currents subject to limits on the forces those coils may carry. The equations representing the current limits and coil force limits are derived and an algorithm based on Newton's method is developed to determine a set of coil currents which satisfies those limits. The resulting program allows the designer to quickly determine whether or not a given coil set is capable of supporting a given equilibrium. 25 refs.

  15. Ring currents and poloidal magnetic fields in nuclear regions of galaxies

    NASA Astrophysics Data System (ADS)

    Lesch, H.; Crusius, A.; Schlickeiser, R.; Wielebinski, R.

    1989-06-01

    The origin of observed strong poloidal magnetic fields R(z) in the central regions of galaxies which have gaseous rings is discussed. In the context of galactic disk dynamo models only weak poloidal fields but strong toroidal fields result. The strength of the poloidal fields is tied to the central activity and apply known and tested ideas rigorously. A battery process on galactic scales is discussed which ensures the existence of a large-scale magnetic field in the inner galactic region. The frozen-in field may be amplified by v x B compression and turbulent stretching; the resulting field is poloidal. The central activity provides a flow field which can produce B(z) equal to or greater than B(phi).

  16. Ion orbit loss and the poloidal electric field in a tokamak

    SciTech Connect

    Xiao, H.; Hazeltine, R.D.; Valanju, P.M.

    1994-07-29

    Monte Carlo simulation studies for ion orbit loss in limiter tokamaks show a poloidal asymmetry in ion loss arising from differences in ion orbit geometry. Since electron loss to the limiter is uniformly distributed because of its tiny orbit width, the nonuniform ion loss could cause a poloidal electric field that would tend to make the ion loss to the limiter more uniform. A simple analytical derivation of this poloidal electric field and a discussion of its effects ion movement and transport are also presented.

  17. On the Sequential Control of ITER Poloidal Field Converters for Reactive Power Reduction

    NASA Astrophysics Data System (ADS)

    Yuan, Hongwen; Fu, Peng; Gao, Ge; Huang, Liansheng; Song, Zhiquan; He, Shiying; Wu, Yanan; Dong, Lin; Wang, Min; Fang, Tongzhen

    2014-12-01

    Sequential control applied to the International Thermonuclear Experimental Reactor (ITER) poloidal field converter system for the purpose of reactive power reduction is the subject of this investigation. Due to the inherent characteristics of thyristor-based phase-controlled converter, the poloidal field converter system consumes a huge amount of reactive power from the grid, which subsequently results in a voltage drop at the 66 kV busbar if no measure is taken. The installation of a static var compensator rated for 750 MVar at the 66 kV busbar is an essential way to compensate reactive power to the grid, which is the most effective measure to solve the problem. However, sequential control of the multi-series converters provides an additional method to improve the natural power factor and thus alleviate the pressure of reactive power demand of the converter system without any additional cost. In the present paper, by comparing with the symmetrical control technique, the advantage of sequential control in reactive power consumption is highlighted. Simulation results based on SIMULINK are found in agreement with the theoretical analysis.

  18. Solutions for the equilibrium of static isothermal gas clouds with poloidal magnetic fields

    NASA Astrophysics Data System (ADS)

    Baureis, P.; Ebert, R.; Schmitz, F.

    1989-11-01

    A family of semi-analytical solutions for the equilibrium of magnetic self-gravitating gas clouds is presented. The configurations are isothermal and axially symmetric; the frozen-in magnetic field is poloidal. Formulating the equilibrium equations of such gas clouds in spherical polar coordinates, a separation of these equations provides simple representative solutions. The radial part of the density distribution is given by the characteristic inverse square of the radial coordinate. The angular parts are governed by a system of nonlinear ordinary differential equations which is solved numerically. The nonmagnetic limit is the isothermal gas sphere with infinite central density. With increasing field strength the configurations flatten. Besides the isothermal sound velocity the value of the magnetic field in the midplane is a free continuous parameter. In the limit of extremely strong fields a thin disk forms. The existence of bounded solutions is discussed, and the models are compared with configurations presented by other authors.

  19. Hall probe measurements of the poloidal magnetic field in Compact Toroidal Hybrid plasmas.

    PubMed

    Stevenson, B A; Knowlton, S F; Hartwell, G J; Hanson, J D; Maurer, D A

    2014-09-01

    A linear array of 16 Hall effect sensors has been developed to directly measure the poloidal magnetic field inside the boundary of a non-axisymmetric hybrid torsatron/tokamak plasma. The array consists of miniature gallium arsenide Hall sensor elements mounted 8 mm apart on a narrow, rotatable printed circuit board inserted into a re-entrant stainless steel tube sheathed in boron nitride. The sensors are calibrated on the bench and in situ to provide accurate local measurements of the magnetic field to aid in reconstructing the equilibrium plasma current density profiles in fully three-dimensional plasmas. Calibrations show that the sensor sensitivities agree with the nominal manufacturers specifications of 1.46 V/T. Poloidal fields measured with the Hall sensor array are found to be within 5% of poloidal fields modeled with a Biot-Savart code.

  20. Hall probe measurements of the poloidal magnetic field in Compact Toroidal Hybrid plasmas

    SciTech Connect

    Stevenson, B. A.; Knowlton, S. F.; Hartwell, G. J. Hanson, J. D.; Maurer, D. A.

    2014-09-15

    A linear array of 16 Hall effect sensors has been developed to directly measure the poloidal magnetic field inside the boundary of a non-axisymmetric hybrid torsatron/tokamak plasma. The array consists of miniature gallium arsenide Hall sensor elements mounted 8 mm apart on a narrow, rotatable printed circuit board inserted into a re-entrant stainless steel tube sheathed in boron nitride. The sensors are calibrated on the bench and in situ to provide accurate local measurements of the magnetic field to aid in reconstructing the equilibrium plasma current density profiles in fully three-dimensional plasmas. Calibrations show that the sensor sensitivities agree with the nominal manufacturers specifications of 1.46 V/T. Poloidal fields measured with the Hall sensor array are found to be within 5% of poloidal fields modeled with a Biot-Savart code.

  1. On Ohmic heating in the Earth's core II: Poloidal magnetic fields obeying Taylor's constraint

    NASA Astrophysics Data System (ADS)

    Jackson, Andrew; Livermore, Philip W.; Ierley, Glenn

    2011-08-01

    The extremely small Ekman and magnetic Rossby numbers in the Earth's core make the magnetostrophic limit an attractive approximation to the core's dynamics. This limit leads to the need for the internal magnetic field to satisfy Taylor's constraint, associated with the vanishing of the azimuthal component of Lorentz torques averaged over every cylinder coaxial with the rotation axis. A special class of three dimensional poloidal interior magnetic fields is chosen that satisfies Taylor's constraint identically on every cylinder in a spherical shell exterior to an inner core. This class of fields, which we call small-circle conservative, demonstrates existence of interior fields satisfying Taylor's constraint, regardless of the morphology of the field on the core surface. These poloidal fields are used to examine the Ohmic dissipation present in the Earth's core. To address the question of dissipation, we demand that the 3-D core fields agree with recent observations of the core field structure on the core-mantle boundary. We use these poloidal fields to show that the true lower bound on core dissipation must necessarily lie below a value that we calculate. For 2004 we find that this lower bound must lie below 10 10 W, and when nutation constraints are also considered the bound must lie below 2 × 10 10 W. These numbers are small compared to suggested values of the order of a few TeraWatts. A more restrictive bound may be forthcoming when the time-dependency of the field is considered, using a variational data assimilation technique.

  2. RESEARCH PAPERS : Secular variation of the poloidal magnetic field at the core-mantle boundary

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Archana

    1998-01-01

    A region of enhanced conductivity at the base of the mantle is modelled by an infinitesimally thin sheet of uniform effective conductance adjacent to the core-mantle boundary. Currents induced in this sheet by the temporally varying magnetic field produced by the geodynamo give rise to a discontinuity in the horizontal components of the poloidal magnetic field on crossing the sheet, while the radial component is continuous across the sheet. Treating the rest of the mantle as an insulator, the horizontal components of the poloidal magnetic field and their secular variation at the top of the core are determined from geomagnetic field, secular variation and secular acceleration models. It is seen that for an assumed effective conductance of the sheet of 108 S, which may be not unrealistic, the changes produced in the horizontal components of the poloidal field at the top of the core are usually <=10 per cent, but corrections to the secular variation in these components at the top of the core are typically 40 per cent, which is greater than the differences that exist between different secular variation models for the same epoch. Given the assumption that all the conductivity of the mantle is concentrated into a thin shell, the present method is not restricted to a weakly conducting mantle. Results obtained are compared with perturbation solutions.

  3. Far-infrared polarimetry/interferometry for poloidal magnetic field measurement on ZT-40M

    SciTech Connect

    Erickson, R.M.

    1986-06-01

    The measurement of internal magnetic field profiles may be a very important step in the understanding of magnetic confinement physics issues. The measurement of plasma-induced Faraday rotation is one of the more promising internal magnetic field diagnostics. This thesis describes the development of a heterodyne polarimeter/interferometer for internal poloidal magnetic field measurement on ZT-40M. Heterodyne techniques were employed because of the insensitivity to spurious signal amplitude changes that cause errors in other methods. Initial problems in polarimetric sensitivity were observed that were ultimately found to be related to discharge-induced motions of the constrained diagnostic access on ZT-40M. Grazing incidence motions of the constrained diagnostic access on ZT-40M. Grazing incidence reflections on metallic surfaces of the diagnostic ports caused polarization changes that affected the measurement accuracy. Installation of internally threaded sleeves to baffle the reflections eliminated the sensitivity problem, and allowed useful Faraday rotation measurements to be made. Simultaneous polarimetric and interferometric measurements have also been demonstrated. The ability to assemble a working heterodyne polarimeter/interferometer is no longer in question. The extension of the present system to multichord operation requires increased laser power and efficiency.

  4. Optimization of Damavand Tokamak Poloidal Field Coils Positions and Currents with PSO Algorithm

    NASA Astrophysics Data System (ADS)

    Mohammadi, M.; Dini, F.; Amrollahi, R.

    2012-04-01

    In order to maintain equilibrium in small or large tokamaks poloidal field coils are utilized, since the function of the poloidal magnetic field is a complex function of current density and the position of the coils, a change in any of the parameters can have a strong effect in the confinement and the magnetohydrodynamic parameters. On the other hand, considering the continuity of the current and the position of the coils, the space being searched is so big that taking all possible conditions into account becomes practically impossible. So a method should be utilized that is able to optimize the position and current of the coils without searching the whole space. This paper seeks to find a new method of deriving the plasma parameter in which a combination of the two methods of neural network and Particles Swarm Optimization is used in order to optimize the position and current of poloidal field coils in Damavand tokamak. Since in the employed methods no special topology is applied, it can be readily used to study any other tokamak.

  5. Gyrokinetic full f analysis of electric field dynamics and poloidal velocity in the FT2-tokamak configuration

    SciTech Connect

    Leerink, S.; Heikkinen, J. A.; Janhunen, S. J.; Kiviniemi, T. P.; Nora, M.; Ogando, F.

    2008-09-15

    The ELMFIRE gyrokinetic simulation code has been used to perform full f simulations of the FT-2 tokamak. The dynamics of the radial electric field and the creation of poloidal velocity in the presence of turbulence are presented.

  6. Microturbulence studies of pulsed poloidal current drive discharges in the reversed field pinch

    SciTech Connect

    Carmody, D. Pueschel, M. J.; Anderson, J. K.; Terry, P. W.

    2015-01-15

    Experimental discharges with pulsed poloidal current drive (PPCD) in the Madison Symmetric Torus reversed field pinch are investigated using a semi-analytic equilibrium model in the gyrokinetic turbulence code GENE. PPCD cases, with plasma currents of 500 kA and 200 kA, exhibit a density-gradient-driven trapped electron mode (TEM) and an ion temperature gradient mode, respectively. Relative to expectations of tokamak core plasmas, the critical gradients for the onset of these instabilities are found to be greater by roughly a factor of the aspect ratio. A significant upshift in the nonlinear TEM transport threshold, previously found for tokamaks, is confirmed in nonlinear reversed field pinch simulations and is roughly three times the threshold for linear instability. The simulated heat fluxes can be brought in agreement with measured diffusivities by introducing a small, resonant magnetic perturbation, thus modeling the residual fluctuations from tearing modes. These fluctuations significantly enhance transport.

  7. A solenoid-free current start-up scenario utilizing outer poloidal field coils*

    NASA Astrophysics Data System (ADS)

    Choe, W.; Kim, J.; Ono, M.; Menard, J.; Neumeyer, C.; Wilson, J. R.

    2004-11-01

    Elimination of the in-board solenoid is not only required for the spherical torus reactors but would also be desirable for advanced tokamak reactors. The challenge for using only the outer PF coils for start-up is the difficulty of creating a sufficiently high quality field null region while retaining the poloidal flux needed for current ramp-up. It is shown that a few pairs of PF coils can provide a field null for a few ms with a large region of low transverse field in which an ionization avalanche can develop in the applied toroidal E-field with the aid of strong pre-ionization. Preliminary experimental and modeling work has been performed on NSTX aimed at quantifying the field null requirements in terms of the Lloyd parameter, the null size and its duration, while optimizing the loop voltage and the available flux. Different combinations of PF coils were used to investigate the relationship between the size of the region where E_TB_T/BP = 0.1 kV/m and the breakdown. Fast camera and magnetic diagnostics clearly show plasma initiation for several ms. The vacuum field patterns and flux surfaces of the generated plasma and analysis of the plasma evolution with the DINA code will be presented. *This work supported by KAIST and DoE Contract No. DE-AC02-76CH03073.

  8. Determination of plasma shape from poloidal field measurements on ISX-B

    SciTech Connect

    Swain, D.W.; Bates, S.; Neilson, G.H.; Peng, Y.K.M.

    1980-03-01

    The ISX-B tokamak has a poloidal coil system designed to produce circular, elliptical, and D-shaped plasmas. Plasma shape and low-order multipole moments of the plasma current distribution are determined from experimental measurements of B/sub Z/, B/sub R/, and/or psi around the periphery of the vacuum chamber. The experimental arrangement and method of analysis of results, using a least squares method to fit the data points to a finite current filament model, are described in this report. Plasma shape results for circular and D-shaped plasmas with b/a less than or equal to 1.5 and an analysis of the sensitivity of the technique to measurement errors are presented. The results indicate that this method gives accurate measurements of the plasma boundary and is relatively insensitivie to errors.

  9. Measurement of Poloidal Velocity on the National Spherical Torus Experiment

    SciTech Connect

    Ronald E. Bell and Russell Feder

    2010-06-04

    A diagnostic suite has been developed to measure impurity poloidal flow using charge exchange recombination spectroscopy on the National Spherical Torus Experiment. Toroidal and poloidal viewing systems measure all quantities required to determine the radial electric field. Two sets of up/down symmetric poloidal views are used to measure both active emission in the plane of the neutral heating beams and background emission in a radial plane away from the neutral beams. Differential velocity measurements isolate the line-integrated poloidal velocity from apparent flows due to the energy-dependent chargeexchange cross section. Six f/1.8 spectrometers measure 276 spectra to obtain 75 active and 63 background channels every 10 ms. Local measurements from a similar midplane toroidal viewing system are mapped into two dimensions to allow the inversion of poloidal line-integrated measurements to obtain local poloidal velocity profiles. Radial resolution after inversion is 0.6-1.8 cm from the plasma edge to the center.

  10. Method and apparatus for steady-state magnetic measurement of poloidal magnetic field near a tokamak plasma

    SciTech Connect

    Woolley, R.D.

    1996-12-31

    A method and apparatus for the steady-state measurement of poloidal magnetic field near a tokamak plasma, where the tokamak is configured with respect to a cylindrical coordinate system having z, phi (toroidal), and r axes. The method is based on combining the two magnetic field principles of induction and torque. The apparatus includes a rotor assembly having a pair of inductive magnetic field pickup coils which are concentrically mounted, orthogonally oriented in the r and z directions, and coupled to remotely located electronics which include electronic integrators for determining magnetic field changes. The rotor assembly includes an axle oriented in the toroidal direction, with the axle mounted on pivot support brackets which in turn are mounted on a baseplate. First and second springs are located between the baseplate and the rotor assembly restricting rotation of the rotor assembly about its axle, the second spring providing a constant tensile preload in the first spring. A strain gauge is mounted on the first spring, and electronic means to continually monitor strain gauge resistance variations is provided. Electronic means for providing a known current pulse waveform to be periodically injected into each coil to create a time-varying torque on the rotor assembly in the toroidal direction causes mechanical strain variations proportional to the torque in the mounting means and springs so that strain gauge measurement of the variation provides periodic magnetic field measurements independent of the magnetic field measured by the electronic integrators.

  11. Method and apparatus for steady-state magnetic measurement of poloidal magnetic field near a tokamak plasma

    DOEpatents

    Woolley, Robert D.

    1998-01-01

    A method and apparatus for the steady-state measurement of poloidal magnetic field near a tokamak plasma, where the tokamak is configured with respect to a cylindrical coordinate system having z, phi (toroidal), and r axes. The method is based on combining the two magnetic field principles of induction and torque. The apparatus includes a rotor assembly having a pair of inductive magnetic field pickup coils which are concentrically mounted, orthogonally oriented in the r and z directions, and coupled to remotely located electronics which include electronic integrators for determining magnetic field changes. The rotor assembly includes an axle oriented in the toroidal direction, with the axle mounted on pivot support brackets which in turn are mounted on a baseplate. First and second springs are located between the baseplate and the rotor assembly restricting rotation of the rotor assembly about its axle, the second spring providing a constant tensile preload in the first spring. A strain gauge is mounted on the first spring, and electronic means to continually monitor strain gauge resistance variations is provided. Electronic means for providing a known current pulse waveform to be periodically injected into each coil to create a time-varying torque on the rotor assembly in the toroidal direction causes mechanical strain variations proportional to the torque in the mounting means and springs so that strain gauge measurement of the variation provides periodic magnetic field measurements independent of the magnetic field measured by the electronic integrators.

  12. Method and apparatus for steady-state magnetic measurement of poloidal magnetic field near a tokamak plasma

    DOEpatents

    Woolley, R.D.

    1998-09-08

    A method and apparatus are disclosed for the steady-state measurement of poloidal magnetic field near a tokamak plasma, where the tokamak is configured with respect to a cylindrical coordinate system having z, phi (toroidal), and r axes. The method is based on combining the two magnetic field principles of induction and torque. The apparatus includes a rotor assembly having a pair of inductive magnetic field pickup coils which are concentrically mounted, orthogonally oriented in the r and z directions, and coupled to remotely located electronics which include electronic integrators for determining magnetic field changes. The rotor assembly includes an axle oriented in the toroidal direction, with the axle mounted on pivot support brackets which in turn are mounted on a baseplate. First and second springs are located between the baseplate and the rotor assembly restricting rotation of the rotor assembly about its axle, the second spring providing a constant tensile preload in the first spring. A strain gauge is mounted on the first spring, and electronic means to continually monitor strain gauge resistance variations is provided. Electronic means for providing a known current pulse waveform to be periodically injected into each coil to create a time-varying torque on the rotor assembly in the toroidal direction causes mechanical strain variations proportional to the torque in the mounting means and springs so that strain gauge measurement of the variation provides periodic magnetic field measurements independent of the magnetic field measured by the electronic integrators. 6 figs.

  13. A simple model for the generation and detection of a poloidal magnetic field in laser-target interactions

    NASA Astrophysics Data System (ADS)

    Ryutov, Dmitri; Remington, Bruce

    2006-10-01

    When a linearly-polarized ultra-intense laser beam interacts with a target, it may generate not only toroidal but also poloidal non-oscillating magnetic field (D.D. Ryutov, B.A. Remington. AIP Conf. Proc., v. 827, p. 341, 2006; Astrophys. Space Sci., submitted, 2006). The poloidal field has a structure resembling the field of a group of four sunspots of alternating polarity. Its magnitude may reach the magnitude of an oscillating magnetic field in the incident wave. Effects of a pulse duration and ion expansion are discussed. Scaling laws determining this field are established. Detection of this field is feasible with side-on ion deflectometry. An optimum orientation of the probe beam is shown to form a 45-degree angle with the polarization plane. Examples of the distortion of an image of a rectangular grid are presented. It is concluded that the poloidal field can be identified even in the presence of the toroidal field of a comparable magnitude. Work performed for US DoE by UC LLNL under contract #W-7405-Eng-48.

  14. Magnetic field pitch angle and perpendicular velocity measurements from multi-point time-delay estimation of poloidal correlation reflectometry

    NASA Astrophysics Data System (ADS)

    Prisiazhniuk, D.; Krämer-Flecken, A.; Conway, G. D.; Happel, T.; Lebschy, A.; Manz, P.; Nikolaeva, V.; Stroth, U.; the ASDEX Upgrade Team

    2017-02-01

    In fusion machines, turbulent eddies are expected to be aligned with the direction of the magnetic field lines and to propagate in the perpendicular direction. Time delay measurements of density fluctuations can be used to calculate the magnetic field pitch angle α and perpendicular velocity {{v}\\bot} profiles. The method is applied to poloidal correlation reflectometry installed at ASDEX Upgrade and TEXTOR, which measure density fluctuations from poloidally and toroidally separated antennas. Validation of the method is achieved by comparing the perpendicular velocity (composed of the E× B drift and the phase velocity of turbulence {{v}\\bot}={{v}E× B}+{{v}\\text{ph}} ) with Doppler reflectometry measurements and with neoclassical {{v}E× B} calculations. An important condition for the application of the method is the presence of turbulence with a sufficiently long decorrelation time. It is shown that at the shear layer the decorrelation time is reduced, limiting the application of the method. The magnetic field pitch angle measured by this method shows the expected dependence on the magnetic field, plasma current and radial position. The profile of the pitch angle reproduces the expected shape and values. However, comparison with the equilibrium reconstruction code cliste suggests an additional inclination of turbulent eddies at the pedestal position (2-3°). This additional angle decreases towards the core and at the edge.

  15. Impact of toroidal and poloidal mode spectra on the control of non-axisymmetric fields in tokamaks

    NASA Astrophysics Data System (ADS)

    Lanctot, Matthew J.

    2016-10-01

    In several tokamaks, non-axisymmetric magnetic field studies show applied n=2 fields can lead to disruptive n=1 locked modes, suggesting nonlinear mode coupling. A multimode plasma response to n=2 fields can be observed in H-mode plasmas, in contrast to the single-mode response found in Ohmic plasmas. These effects highlight a role for n >1 error field correction in disruption avoidance, and identify additional degrees of freedom for 3D field optimization at high plasma pressure. In COMPASS, EAST, and DIII-D Ohmic plasmas, n=2 magnetic reconnection thresholds in otherwise stable discharges are readily accessed at edge safety factors q 3 and low density. Similar to previous studies, the thresholds are correlated with the ``overlap'' field for the dominant linear ideal MHD plasma mode calculated with the IPEC code. The overlap field measures the plasma-mediated coupling of the external field to the resonant field. Remarkably, the critical overlap fields are similar for n=1 and 2 fields with m >nq fields dominating the drive for resonant fields. Complementary experiments in RFX-Mod show fields with m fields in DIII-D elicit transport responses with differing poloidal spectrum dependences, including a reduction in toroidal angular momentum that is not fully recoverable using fields that imperfectly match the applied field. These results have motivated an international effort to document n=2 error field thresholds in order to establish control requirements for ITER. This work highlights unique requirements for n >1 control, including the need for multiple rows of coils to control selected plasma parameters for specific functions (e.g., rotation control or ELM suppression). Optimal multi-harmonic (n=1 and n=2) error field control may be achieved using control algorithms that continuously respond to time-varying 3D field sources and plasma parameters. Supported by the US DOE under DE-FC02-04ER54698.

  16. Poloidal Rotation Dynamics, Radial Electric Field, and Neoclassical Theory in the Jet Internal-Transport-Barrier Region

    SciTech Connect

    Crombe, K.; Oost, G. van; Andrew, Y.; Giroud, C.; Hawkes, N. C.; Parail, V.; Voitsekhovitch, I.; Zastrow, K.-D.; Hacquin, S.; Nave, M.F.F.; Ongena, J.

    2005-10-07

    Results from the first measurements of a core plasma poloidal rotation velocity (v{sub {theta}}) across internal transport barriers (ITB) on JET are presented. The spatial and temporal evolution of the ITB can be followed along with the v{sub {theta}} radial profiles, providing a very clear link between the location of the steepest region of the ion temperature gradient and localized spin-up of v{sub {theta}}. The v{sub {theta}} measurements are an order of magnitude higher than the neoclassical predictions for thermal particles in the ITB region, contrary to the close agreement found between the determined and predicted particle and heat transport coefficients [K.-D. Zastrow et al., Plasma Phys. Controlled Fusion 46, B255 (2004)]. These results have significant implications for the understanding of transport barrier dynamics due to their large impact on the measured radial electric field profile.

  17. A method for determining poloidal rotation from poloidal asymmetry in toroidal rotation (invited).

    PubMed

    Chrystal, C; Burrell, K H; Grierson, B A; Lao, L L; Pace, D C

    2014-11-01

    A new diagnostic has been developed on DIII-D that determines the impurity poloidal rotation from the poloidal asymmetry in the toroidal angular rotation velocity. This asymmetry is measured with recently added tangential charge exchange viewchords on the high-field side of the tokamak midplane. Measurements are made on co- and counter-current neutral beams, allowing the charge exchange cross section effect to be measured and eliminating the need for atomic physics calculations. The diagnostic implementation on DIII-D restricts the measurement range to the core (r/a < 0.6) where, relative to measurements made with the vertical charge exchange system, the spatial resolution is improved. Significant physics results have been obtained with this new diagnostic; for example, poloidal rotation measurements that significantly exceed neoclassical predictions.

  18. MAGNETIC FIELD CONFIGURATION AT THE GALACTIC CENTER INVESTIGATED BY WIDE-FIELD NEAR-INFRARED POLARIMETRY: TRANSITION FROM A TOROIDAL TO A POLOIDAL MAGNETIC FIELD

    SciTech Connect

    Nishiyama, Shogo; Yoshikawa, Tatsuhito; Nagata, Tetsuya; Hatano, Hirofumi; Nagayama, Takahiro; Tamura, Motohide; Matsunaga, Noriyuki; Suenaga, Takuya; Hough, James H.; Sugitani, Koji; Kato, Daisuke

    2010-10-10

    We present a large-scale view of the magnetic field (MF) in the central 2{sup 0} x 2{sup 0} region of our Galaxy. The polarization of point sources has been measured in the J, H, and K{sub S} bands using the near-infrared polarimetric camera SIRPOL on the 1.4 m Infrared Survey Facility telescope. Comparing the Stokes parameters between high extinction stars and relatively low extinction ones, we obtain polarization originating from magnetically aligned dust grains in the central few hundred parsecs of our Galaxy. We find that near the Galactic plane, the MF is almost parallel to the Galactic plane (i.e., toroidal configuration), but at high Galactic latitudes (|b | >0.{sup 0}4) the field is nearly perpendicular to the plane (i.e., poloidal configuration). This is the first detection of a smooth transition of the large-scale MF configuration in this region.

  19. Spitzer or neoclassical resistivity: A comparison between measured and model poloidal field profiles on PBX-M

    SciTech Connect

    Kaye, S.M.; Hatcher, R.; Kaita, R.; Kessel, C.; LeBlanc, B.; McCune, D.C.; Paul, S.; Levinton, F.M.

    1992-01-01

    Direct measurements of the radial profile of the magnetic field line pitch on PBX-M coupled with model predictions of these profiles allow a critical comparison with the Spitzer and neoclassical models of plasma parallel resistivity. The measurements of the magnetic field line pitch are made by Motional Stark Effect polarimetry, while the model profiles are determined by solving the poloidal field diffusion equation in the TRANSP transport code using measured plasma profiles and assuming either Spitzer or neoclassical resistivity. The measured field pitch profiles were available for only seven cases, and the model profiles were distinguishable from each other in only three of those cases due to finite resistive diffusion times. The data in two of these three were best matched by the Spitzer model, especially in the inner half of the plasma. Portions of the measured pitch profiles for these two cases and the full profiles for other cases, however, departed significantly from both the Spitzer and neoclassical models, indicating a plasma resistivity profile different from either model.

  20. Dependence of neoclassical toroidal viscosity on the poloidal spectrum of applied nonaxisymmetric fields

    SciTech Connect

    Logan, Nikolas C.; Park, Jong -Kyu; Paz-Soldan, Carloa; Lanctot, Matthew J.; Smith, Sterling P.; Burrell, K. H.

    2016-02-05

    This paper presents a single mode model that accurately predicts the coupling of applied nonaxisymmetric fields to the plasma response that induces neoclassical toroidal viscosity (NTV) torque in DIII-D H-mode plasmas. The torque is measured and modeled to have a sinusoidal dependence on the relative phase of multiple nonaxisymmetric field sources, including a minimum in which large amounts of nonaxisymmetric drive is decoupled from the NTV torque. This corresponds to the coupling and decoupling of the applied field to a NTV-driving mode spectrum. Modeling using the perturbed equilibrium nonambipolar transport (PENT) code confirms an effective single mode coupling between the applied field and the resultant torque, despite its inherent nonlinearity. Lastly, the coupling to the NTV mode is shown to have a similar dependence on the relative phasing as that of the IPEC dominant mode, providing a physical basis for the efficacy of this linear metric in predicting error field correction optima in NTV dominated regimes.

  1. Dependence of neoclassical toroidal viscosity on the poloidal spectrum of applied nonaxisymmetric fields

    DOE PAGES

    Logan, Nikolas C.; Park, Jong -Kyu; Paz-Soldan, Carloa; ...

    2016-02-05

    This paper presents a single mode model that accurately predicts the coupling of applied nonaxisymmetric fields to the plasma response that induces neoclassical toroidal viscosity (NTV) torque in DIII-D H-mode plasmas. The torque is measured and modeled to have a sinusoidal dependence on the relative phase of multiple nonaxisymmetric field sources, including a minimum in which large amounts of nonaxisymmetric drive is decoupled from the NTV torque. This corresponds to the coupling and decoupling of the applied field to a NTV-driving mode spectrum. Modeling using the perturbed equilibrium nonambipolar transport (PENT) code confirms an effective single mode coupling between themore » applied field and the resultant torque, despite its inherent nonlinearity. Lastly, the coupling to the NTV mode is shown to have a similar dependence on the relative phasing as that of the IPEC dominant mode, providing a physical basis for the efficacy of this linear metric in predicting error field correction optima in NTV dominated regimes.« less

  2. From poloidal to toroidal: Detection of a well-ordered magnetic field in the high-mass protocluster G35.2–0.74 N

    SciTech Connect

    Qiu, Keping; Zhang, Qizhou; Menten, Karl M.; Liu, Hauyu B.; Tang, Ya-Wen

    2013-12-20

    We report the detection of an ordered magnetic field threading a cluster-forming clump in the molecular cloud G35.2–0.74 using Submillimeter Array observations of polarized dust emission. We resolve the morphology of the magnetic field in the plane of sky and detect a great turn of 90° in the field direction: over the northern part of the clump, where a velocity gradient is evident, the magnetic field is aligned along the long axis of the clump, whereas in the southern part, where the velocity structure appears relatively uniform, the field is aligned perpendicular to the clump. Taking into account early single-disk data, we suggest that the clump forms as its parent cloud collapses more along the magnetic field. The northern part of the clump carries over angular momentum from the cloud, forming a fast rotating system, and the magnetic field is pulled into a toroidal configuration. In contrast, the southern part is not significantly rotating and retains a poloidal field. A statistical analysis of the observed polarization dispersion yields a field strength of ∼1 mG. Detailed calculations support our hypothesis of a rotationally twisted magnetic field in the northern part. The observations suggest that the magnetic field may play a critical role in the formation of the dense clump, while in its further dynamical evolution, rotation and turbulence can also be important. In addition, our observations provide evidence for a wide-angle outflow driven from a strongly rotating region whose magnetic field is largely toroidal.

  3. Solenoid-free toroidal plasma start-up concepts utilizing only the outer poloidal field coils and a conducting centre-post

    NASA Astrophysics Data System (ADS)

    Choe, Wonho; Kim, Jayhyun; Ono, Masayuki

    2005-12-01

    Eventual elimination of the in-board Ohmic heating solenoid is required for the spherical torus (ST) to function as a compact component test facility and as an attractive fusion power plant. An in-board Ohmic solenoid, along with the shielding needed for its insulation, can dramatically increase the size and, hence, the cost of the plant. Advanced tokamak reactor designs also assume no or a small in-board solenoid to reduce the size and cost of the plant. In addition, elimination of the in-board solenoid greatly reduces the coil stresses and simplifies the coil design. Here, we investigate using static as well as dynamic codes in ST geometries with two complementary solenoid-free plasma start-up approaches: one utilizes only the outer poloidal field coils to create a relatively high quality field null region while retaining significant poloidal flux, and the other takes advantage of the poloidal flux stored in the conducting centre-post to create a start-up condition similar to that of the conventional Ohmic solenoid method. We find that it is therefore possible to come up with a promising configuration, which produces a quality multi-pole field-null and sufficient loop-voltage needed for plasma initiation and significant poloidal flux for subsequent current ramp-up. The present solenoid-free start-up concept, if proved feasible, can be readily extended to higher field devices due to relatively simple physics principles and favourable scaling with the device size and toroidal field.

  4. Laboratory formation of a scaled protostellar jet by coaligned poloidal magnetic field: recent results and new exeprimental studies

    NASA Astrophysics Data System (ADS)

    Vinci, Tommaso; Revet, Guilhem; Higginson, Drew; Béard, Jérome; Burdonov, K.; Chen, Sophia; Khagani, D.; Khiar, B.; Naughton, K.; Pikuz, S.; Riconda, Caterina; Riquier, R.; Soloviev, A.; Willi, O.; Portugall, O.; Pépin, Henry; Ciardi, Andrea; Fuchs, Julien; Albertazzi, Bruno

    2015-08-01

    Accretion shocks in Young Stellar Objects (YSO) are a subject of great interest in astrophysics; they exhibit intense magnetic activity and are surrounded by an accretion disk from which matter falls down onto the stellar surface in the form of columns following the magnetic lines (B ~ kG) at the free-fall velocity (100-500 km/s). As a column impacts the stellar surface, a radiative shock is created which heats up the infalling flow. As a consequence, a new reverse shock forms and some oscillations are expected in the emitted radiation as a proof of this periodic dynamic, but no periodicity has yet been detected in observations.To understand the reasons for this apparent inconsistency, we have recently developped an experimental setup [B. Albertazzi et al. Science 346, 325 (2014)] in which a plasma flow (generated by a high energy laser: 1013 W/cm2 - 0.6 ns pulse) is confined inside a poloidal magnetic field (20 T). This jet has an aspect ratio >10, a temperature of tens of eV, an electron density of 1018 cm-3 and propagates at 700 km/s as show by our previous numerical work [A. Ciardi et al. Physical Review Letters, 110 (2013)]. To investigate the accretion dynamics, the jet acts as the accretion column and hits a secondary target acting as the stellar surface. We will present the recent results on generation and dynamics of the jet and the new experimental results of this configuration, namely of a supersonic reverse shock traveling within the accretion column with a speed of 100 km/s, representing a Mach number of ~ 30, and the observation of increased density structures along the edges of the interaction. This will be discussed in the light of 3D-magneto-hydrodynamic simulations which parametric variations allow to understand how the various plasma parameters affect the accretion.

  5. Radial and poloidal correlation reflectometry on Experimental Advanced Superconducting Tokamak

    SciTech Connect

    Qu, Hao; Zhang, Tao; Han, Xiang; Wen, Fei; Zhang, Shoubiao; Kong, Defeng; Wang, Yumin; Gao, Yu; Huang, Canbin; Cai, Jianqing; Gao, Xiang

    2015-08-15

    An X-mode polarized V band (50 GHz–75 GHz) radial and poloidal correlation reflectometry is designed and installed on Experimental Advanced Superconducting Tokamak (EAST). Two frequency synthesizers (12 GHz–19 GHz) are used as sources. Signals from the sources are up-converted to V band using active quadruplers and then coupled together for launching through one single pyramidal antenna. Two poloidally separated antennae are installed to receive the reflected waves from plasma. This reflectometry system can be used for radial and poloidal correlation measurement of the electron density fluctuation. In ohmically heated plasma, the radial correlation length is about 1.5 cm measured by the system. The poloidal correlation analysis provides a means to estimate the fluctuation velocity perpendicular to the main magnetic field. In the present paper, the distance between two poloidal probing points is calculated with ray-tracing code and the propagation time is deduced from cross-phase spectrum. Fluctuation velocity perpendicular to the main magnetic field in the core of ohmically heated plasma is about from −1 km/s to −3 km/s.

  6. Radial and poloidal correlation reflectometry on Experimental Advanced Superconducting Tokamak.

    PubMed

    Qu, Hao; Zhang, Tao; Han, Xiang; Wen, Fei; Zhang, Shoubiao; Kong, Defeng; Wang, Yumin; Gao, Yu; Huang, Canbin; Cai, Jianqing; Gao, Xiang

    2015-08-01

    An X-mode polarized V band (50 GHz-75 GHz) radial and poloidal correlation reflectometry is designed and installed on Experimental Advanced Superconducting Tokamak (EAST). Two frequency synthesizers (12 GHz-19 GHz) are used as sources. Signals from the sources are up-converted to V band using active quadruplers and then coupled together for launching through one single pyramidal antenna. Two poloidally separated antennae are installed to receive the reflected waves from plasma. This reflectometry system can be used for radial and poloidal correlation measurement of the electron density fluctuation. In ohmically heated plasma, the radial correlation length is about 1.5 cm measured by the system. The poloidal correlation analysis provides a means to estimate the fluctuation velocity perpendicular to the main magnetic field. In the present paper, the distance between two poloidal probing points is calculated with ray-tracing code and the propagation time is deduced from cross-phase spectrum. Fluctuation velocity perpendicular to the main magnetic field in the core of ohmically heated plasma is about from -1 km/s to -3 km/s.

  7. Inboard and outboard radial electric field wells in the H- and I-mode pedestal of Alcator C-Mod and poloidal variations of impurity temperature

    NASA Astrophysics Data System (ADS)

    Theiler, C.; Churchill, R. M.; Lipschultz, B.; Landreman, M.; Ernst, D. R.; Hughes, J. W.; Catto, P. J.; Parra, F. I.; Hutchinson, I. H.; Reinke, M. L.; Hubbard, A. E.; Marmar, E. S.; Terry, J. T.; Walk, J. R.; the Alcator C-Mod Team

    2014-08-01

    We present inboard (HFS) and outboard (LFS) radial electric field (Er) and impurity temperature (Tz) measurements in the I-mode and H-mode pedestal of Alcator C-Mod. These measurements reveal strong Er wells at the HFS and the LFS midplane in both regimes and clear pedestals in Tz, which are of similar shape and height for the HFS and LFS. While the H-mode Er well has a radially symmetric structure, the Er well in I-mode is asymmetric, with a stronger ExB shear layer at the outer edge of the Er well, near the separatrix. Comparison of HFS and LFS profiles indicates that impurity temperature and plasma potential are not simultaneously flux functions. Uncertainties in radial alignment after mapping HFS measurements along flux surfaces to the LFS do not, however, allow direct determination as to which quantity varies poloidally and to what extent. Radially aligning HFS and LFS measurements based on the Tz profiles would result in substantial inboard-outboard variations of plasma potential and electron density. Aligning HFS and LFS Er wells instead also approximately aligns the impurity poloidal flow profiles, while resulting in a LFS impurity temperature exceeding the HFS values in the region of steepest gradients by up to 70%. Considerations based on a simplified form of total parallel momentum balance and estimates of parallel and perpendicular heat transport time scales seem to favor an approximate alignment of the Er wells and a substantial poloidal asymmetry in impurity temperature.

  8. Poloidal OHMIC heating in a multipole

    SciTech Connect

    Holly, D.J.

    1982-01-01

    The feasibility of using poloidal currents to heat plasmas confined by a multipole field has been examined experimentaly in Tokapole II. The machine is operated as a toroidal octupole, with a time-varying toroidal magnetic field driving poloidal plasma currents I/sub plasma/ - 20 kA to give densities n/sub e/ - 10/sup 13/ cm/sup -3/ and temperatures T/sub e/ - 30 eV.

  9. Heat flux and plasma flow in the far scrape-off layer of the inboard poloidal field null configuration in QUEST

    SciTech Connect

    Onchi, T.; Zushi, H.; Hanada, K.; Idei, H.; Hasegawa, M.; Nakamura, K.; Fujisawa, A.; Nagashima, Y.; Matsuoka, K.; Kuzmin, A.; Kawasaki, S.; Nakashima, H.; Higashijima, A.; Watanabe, O.; Mishra, K.; Mahira, Y.; Tashima, S.; Banerjee, S.; Nagaoka, K.

    2015-08-15

    Heat flux and plasma flow in the scrape-off layer (SOL) are examined for the inboard poloidal field null (IPN) configuration of the spherical tokamak QUEST. In the plasma current (I{sub p}) ramp-up phase, high heat flux (>1 MW/m{sup 2}) and supersonic flow (Mach number M > 1) are found to be present simultaneously in the far-SOL. The heat flux is generated by energetic electrons excursed from the last closed flux surface. Supersonic flows in the poloidal and toroidal directions are correlated with each other. In the quasi-steady state, sawtooth-like oscillation of I{sub p} at 20 Hz is observed. Heat flux and subsonic plasma flow in the far-SOL are modified corresponding to the I{sub p}-oscillation. The heat flow caused by motion of energetic electrons and the bulk-particle transport to the far-SOL is enhanced during the low-I{sub p} phase. Modification of plasma flow in the far SOL occurs earlier than the I{sub p} crash. The M–I{sub p} curve has a limit-cycle characteristic with sawtooth-like oscillation. Such a core–SOL relationship indicates that the far-SOL flow plays an important role in sustaining the oscillation of I{sub p} in the IPN configuration.

  10. Blob dynamics in TORPEX poloidal null configurations

    NASA Astrophysics Data System (ADS)

    Shanahan, B. W.; Dudson, B. D.

    2016-12-01

    3D blob dynamics are simulated in X-point magnetic configurations in the TORPEX device via a non-field-aligned coordinate system, using an isothermal model which evolves density, vorticity, parallel velocity and parallel current density. By modifying the parallel gradient operator to include perpendicular perturbations from poloidal field coils, numerical singularities associated with field aligned coordinates are avoided. A comparison with a previously developed analytical model (Avino 2016 Phys. Rev. Lett. 116 105001) is performed and an agreement is found with minimal modification. Experimental comparison determines that the null region can cause an acceleration of filaments due to increasing connection length, but this acceleration is small relative to other effects, which we quantify. Experimental measurements (Avino 2016 Phys. Rev. Lett. 116 105001) are reproduced, and the dominant acceleration mechanism is identified as that of a developing dipole in a moving background. Contributions from increasing connection length close to the null point are a small correction.

  11. A method for determining poloidal coil configurations for tokamak devices

    SciTech Connect

    Evans, K. Jr.

    1990-12-01

    This paper presents a method for obtaining the locations and currents of the poloidal coil systems for a tokamak, given an desirable magnetohydrodynamic equilibrium for the device. The method involves a simultaneous minimization of the match to the desired poloidal field and the stored energy in the coils, subject to the constraints necessary to achieve decoupling of the equilibrium and inductive-current-drive (ohmic-heating) systems and to achieve a given coupling of the current-drive system with the plasma. A compendium of mutual and self-inductance formulas as they apply to tokamak systems is presented, as well as examples of how the method has been used in the design of several tokamaks. Finally, a user manual for a computer code that implements this method is provided. 14 refs., 11 figs., 1 tab.

  12. Optimization of Outer Poloidal Field (PF) Coil Configurations for Inductive PF Coil-only Plasma Start-up on Spherical Tori

    SciTech Connect

    Wonho Choe; Jayhyun Kim; Masayuki Ono

    2004-04-09

    The elimination of in-board ohmic heating solenoid is required for the spherical torus (ST) to function as an attractive fusion power plant. An in-board ohmic solenoid, along with the shielding needed for its insulation, increases the size and, hence, the cost of the plant. Here, we investigate using static as well as dynamic codes in ST geometries a solenoid-free start-up concept utilizing a set of out-board poloidal field coils. By using the static code, an optimization of coil positions as well as coil currents was performed to demonstrate that it is indeed possible to create a high quality multi-pole field null region while retaining significant flux (volt-seconds) needed for the subsequent current ramp-up. With the dynamic code that includes the effect of vacuum vessel eddy currents, we then showed that it is possible to maintain a large size field null region for several milliseconds in which sufficient ionization avalanche can develop in the applied toroidal electric field. Under the magnetic geometry typical of a next generation spherical torus experiment, it is shown that the well-known plasma breakdown conditions for conventional ohmic solenoid start-up of E(sub)TB(sub)T/B(sub)P {approx} (0.1-1) kV/m with V(sub)loop {approx} 6 V can be readily met while retaining significant volt-seconds {approx} 4 V-S sufficient to generate multi-MA plasma current in STs.

  13. Spheromak reactor with poloidal flux-amplifying transformer

    DOEpatents

    Furth, Harold P.; Janos, Alan C.; Uyama, Tadao; Yamada, Masaaki

    1987-01-01

    An inductive transformer in the form of a solenoidal coils aligned along the major axis of a flux core induces poloidal flux along the flux core's axis. The current in the solenoidal coil is then reversed resulting in a poloidal flux swing and the conversion of a portion of the poloidal flux to a toroidal flux in generating a spheromak plasma wherein equilibrium approaches a force-free, minimum Taylor state during plasma formation, independent of the initial conditions or details of the formation. The spheromak plasma is sustained with the Taylor state maintained by oscillating the currents in the poloidal and toroidal field coils within the plasma-forming flux core. The poloidal flux transformer may be used either as an amplifier stage in a moving plasma reactor scenario for initial production of a spheromak plasma or as a method for sustaining a stationary plasma and further heating it. The solenoidal coil embodiment of the poloidal flux transformer can alternately be used in combination with a center conductive cylinder aligned along the length and outside of the solenoidal coil. This poloidal flux-amplifying inductive transformer approach allows for a relaxation of demanding current carrying requirements on the spheromak reactor's flux core, reduces plasma contamination arising from high voltage electrode discharge, and improves the efficiency of poloidal flux injection.

  14. Global electromagnetic induction in the moon and planets. [poloidal eddy current transient response

    NASA Technical Reports Server (NTRS)

    Dyal, P.; Parkin, C. W.

    1973-01-01

    Experiments and analyses concerning electromagnetic induction in the moon and other extraterrestrial bodies are summarized. The theory of classical electromagnetic induction in a sphere is first considered, and this treatment is extended to the case of the moon, where poloidal eddy-current response has been found experimentally to dominate other induction modes. Analysis of lunar poloidal induction yields lunar internal electrical conductivity and temperature profiles. Two poloidal-induction analytical techniques are discussed: a transient-response method applied to time-series magnetometer data, and a harmonic-analysis method applied to data numerically Fourier-transformed to the frequency domain, with emphasis on the former technique. Attention is given to complicating effects of the solar wind interaction with both induced poloidal fields and remanent steady fields. The static magnetization field induction mode is described, from which are calculated bulk magnetic permeability profiles. Magnetic field measurements obtained from the moon and from fly-bys of Venus and Mars are studied to determine the feasibility of extending theoretical and experimental induction techniques to other bodies in the solar system.

  15. Density Threshold for Edge Poloidal Flow Generation

    NASA Astrophysics Data System (ADS)

    Daniels, N.; Ware, A. S.; Newman, D. E.; Hidalgo, C.

    2004-11-01

    A numerical transport model is used to examine a density threshold for the onset of an edge poloidal velocity shear layer in toroidal devices. This work is motivated by recent experimental results from the TJ-II stellarator which indicate a critical density threshold for the development of an edge poloidal velocity shear layer [1]. Edge shear-flow layers are commonly observed in toroidal confinement devices, even in L-mode discharges. The numerical transport model has been used to examine internal transport barriers and front propagation of internal transport barriers [2]. The transport model couples together density, ion temperature, electron temperature, poloidal flow, toroidal flow, radial electric field, and a fluctuation envelope equation which includes a shear-suppression factor. In this work, we present results from a series of cases using parameters that are typical of TJ-II discharges. The dependence of the critical density threshold on flow damping and Reynolds stress drive is investigated. [1] C. Hidalgo, M. A. Pedrosa, L. Garcia, and A. Ware, "Direct experimental evidence of coupling between sheared flows development and increasing in level of turbulence in the TJ-II stellarator", submitted to Phys. Rev. E. [2] D. E. Newman, B. A. Carreras, D. Lopez-Bruna, P. H. Diamond, and V. B. Lebedev, Phys. Plasmas 5, 938 (1998).

  16. Poloidal Asymmetries in Edge Transport Barriers

    NASA Astrophysics Data System (ADS)

    Churchill, R. M.

    2014-10-01

    Investigations of the poloidal structure within edge transport barriers on Alcator C-Mod using novel impurity measurements are presented, revealing large poloidal variations of parameters within a flux surface in the H-mode pedestal region, and significantly reduced poloidal variation in L-mode or I-mode pedestals. These measurements provide complete sets of impurity density, temperature, flow velocity, and electrostatic potential at both the low- and high-field side midplane, utilizing the Gas Puff-CXRS technique. Uncertainties in magnetic equilibrium reconstructions require assumptions to be made in order to properly align the LFS/HFS profiles. In H-mode plasmas, if profiles are aligned assuming impurity temperature is constant on a flux surface, large potential asymmetries would result (eΔΦ /Te ~ 0 . 6). If instead total pressure is assumed constant on a flux-surface, then the measured potential asymmetry is significantly reduced, but large in-out asymmetries result in the impurity temperature (>1.7x). This shows that impurity temperature and potential can not both be flux functions in the pedestal region. In both alignment cases, large asymmetries in impurity density (>6x) are present in H-mode plasmas. In I-mode plasmas, which lack an electron density pedestal but do have a temperature pedestal, the poloidal variation of impurity temperature is weaker (~1.3x) and the impurity density nearly symmetric between the LFS and HFS. These measurements indicate that the sharp gradients in the pedestal region, particularly of main ion density, have a significant effect on the poloidal and radial distribution of impurities, which could have important implications for the prediction of impurity contamination in future fusion reactors such as ITER. Estimates of particle and heat transport timescales suggest that the radial and parallel transport timescales are of the same order in the pedestal region of C-Mod, supporting the idea that two-dimensional transport effects

  17. Strongly magnetized accretion discs require poloidal flux

    NASA Astrophysics Data System (ADS)

    Salvesen, Greg; Armitage, Philip J.; Simon, Jacob B.; Begelman, Mitchell C.

    2016-08-01

    Motivated by indirect observational evidence for strongly magnetized accretion discs around black holes, and the novel theoretical properties of such solutions, we investigate how a strong magnetization state can develop and persist. To this end, we perform local simulations of accretion discs with an initially purely toroidal magnetic field of equipartition strength. We demonstrate that discs with zero net vertical magnetic flux and realistic boundary conditions cannot sustain a strong toroidal field. However, a magnetic pressure-dominated disc can form from an initial configuration with a sufficient amount of net vertical flux and realistic boundary conditions. Our results suggest that poloidal flux is a necessary prerequisite for the sustainability of strongly magnetized accretion discs.

  18. Theoretical explanation for strong poloidal impurity asymmetry in tokamak pedestals

    NASA Astrophysics Data System (ADS)

    Espinosa, Silvia

    2016-10-01

    Stronger impurity density in-out poloidal asymmetries than predicted by the most comprehensive neoclassical models have been measured in H-mode tokamak pedestals during the last decade. However, these pioneering theories neglect the impurity diamagnetic drift, while recent measurements indicate that it can be of the same order as the ExB drift that is retained. In order to keep both drifts self-consistently, stronger radial gradients of the impurity density must be allowed. As a result, radial impurity flow effects need to be included for the first time. These effects substantially alter the parallel impurity flow. The resulting modification in the impurity friction with the banana regime background ions then allows stronger poloidal variation of the impurity density, temperature and potential. Even the six-fold high field side accumulation of boron density measured on Alcator C-Mod can be explained without invoking anomalous transport. Moreover, the potential can no longer be assumed to be a flux function since the impurity density variation gives a poloidally varying potential that results in strong poloidal variation of the radial electric field. The fact that the magnitude of the negative radial electric field and the impurity temperature are both larger on the low field side is also correctly predicted. Finally, this pedestal neoclassical model with radial flows may provide insight on how to control impurity accumulation in JET. Supported by DOE Grant DE-FG0291ER54109 and La Caixa Fellowship.

  19. Method of sustaining a radial electric field and poloidal plasma rotation over most of the cross-section of a tokamak

    DOEpatents

    Darrow, Douglass S.; Ono, Masayuki

    1990-03-06

    A radial electric field of a desired magnitude and configuration is created throughout a substantial portion of the cross-section of the plasma of a tokamak. The radial electric field is created by injection of a unidirectional electron beam. The magnitude and configuration of the radial electric field may be controlled by the strength of the toroidal magnetic field of the tokamak.

  20. Method of sustaining a radial electric field and poloidal plasma rotation over most of the cross-section of a tokamak

    DOEpatents

    Darrow, Douglass S.; Ono, Masayuki

    1990-01-01

    A radial electric field of a desired magnitude and configuration is created hroughout a substantial portion of the cross-section of the plasma of a tokamak. The radial electric field is created by injection of a unidirectional electron beam. The magnitude and configuration of the radial electric field may be controlled by the strength of the toroidal magnetic field of the tokamak.

  1. Excitation of Poloidal standing Alfven waves through drift resonance wave-particle interaction (Invited)

    NASA Astrophysics Data System (ADS)

    Dai, L.; Takahashi, K.; Wygant, J. R.; Chen, L.; Bonnell, J. W.; Cattell, C. A.; Thaller, S. A.; Kletzing, C.; Smith, C. W.; MacDowall, R. J.; Baker, D. N.; Blake, J. B.; Fennell, J. F.; Claudepierre, S. G.; Funsten, H. O.; Reeves, G. D.; Spence, H.

    2013-12-01

    Charged particles trapped in the magnetosphere undergo a longitudinal drift motion around the Earth induced by the magnetic field curvature and gradient. The resonant wave-particle interaction associated with the drift motion is important for understanding the dynamics of the ring current and radiation belt particles. Using cross-spectral analysis of electric field, magnetic field, and ion flux data from the Van Allen Probe (RBSP) spacecraft, we present direct evidence identifying the generation of a fundamental mode standing poloidal wave through drift-resonance interactions in the inner magnetosphere. Intense azimuthal electric field (E φ ) oscillations as large as 10mV/m are observed associated with radial magnetic field (Br) oscillations in the dawn-noon sector near but south of the magnetic equator at L~5. The observed wave period, Eφ/Br, and the 90 degrees phase lag between Br and Eφ are all consistent with fundamental mode standing poloidal waves. Phase shifts between particle fluxes and wave electric fields clearly demonstrate a drift resonance with ~90 keV ring current ions. The estimated earthward gradient of ion phase space density provides free energy source for wave generation through the drift-resonance instability. To our knowledge, this is the first unambiguous observation of drift-resonance wave-particle interaction driving poloidal wave oscillations in the magnetosphere. Similar drift-resonance process should occur ubiquitously in collisionless plasma systems. One example is the ';fishbone' instability in fusion plasma devices. In addition, our observations have important implications for the long-standing mysterious origin of Giant Pulsations detected on the ground.

  2. Impact of plasma poloidal rotation on resistive wall mode instability in toroidally rotating plasmas

    SciTech Connect

    Aiba, N.; Shiraishi, J.; Tokuda, S.

    2011-02-15

    Stability of resistive wall mode (RWM) is investigated in a cylindrical plasma and an axisymmetric toroidal plasma by taking into account not only toroidal rotation but also poloidal rotation. Since the Doppler shifted frequency is responsible for the RWM stability, the modification of this Doppler shifted frequency by poloidal rotation affects the rotation effect on RWM. When a poloidal rotation frequency is not so large, the effect of poloidal rotation on the RWM stability can be approximately treated with the modified toroidal rotation frequency. In a toroidal plasma, this modified frequency is determined by subtracting a toroidal component of the rotation parallel to the magnetic field from the toroidal rotation frequency. The poloidal rotation that counteracts the effect of the Doppler shift strongly reduces the stabilizing effect of toroidal rotation, but by changing the rotational direction, the poloidal rotation enhances this stabilizing effect. This trend is confirmed in not only a cylindrical plasma but also a toroidal plasma. This result indicates that poloidal rotation produces the dependence of the critical toroidal rotation frequency for stabilizing RWM on the rotational direction of toroidal rotation in the same magnetic configuration.

  3. Excitation of poloidal standing Alfvén waves through drift resonance wave-particle interaction

    NASA Astrophysics Data System (ADS)

    Dai, Lei; Takahashi, Kazue; Wygant, John R.; Chen, Liu; Bonnell, John; Cattell, Cynthia A.; Thaller, Scott; Kletzing, Craig; Smith, Charles W.; MacDowall, Robert J.; Baker, Daniel N.; Blake, J. Bernard; Fennell, Joseph; Claudepierre, Seth; Funsten, Herbert O.; Reeves, Geoffrey D.; Spence, Harlan E.

    2013-08-01

    Drift-resonance wave-particle interaction is a fundamental collisionless plasma process studied extensively in theory. Using cross-spectral analysis of electric field, magnetic field, and ion flux data from the Van Allen Probe (Radiation Belt Storm Probes) spacecraft, we present direct evidence identifying the generation of a fundamental mode standing poloidal wave through drift-resonance interactions in the inner magnetosphere. Intense azimuthal electric field (Eφ) oscillations as large as 10mV/m are observed, associated with radial magnetic field (Br) oscillations in the dawn-noon sector near but south of the magnetic equator at L˜5. The observed wave period, Eφ/Br ratio and the 90° phase lag between Br and Eφ are all consistent with fundamental mode standing Poloidal waves. Phase shifts between particle fluxes and wave electric fields clearly demonstrate a drift resonance with ˜90 keV ring current ions. The estimated earthward gradient of ion phase space density provides a free energy source for wave generation through the drift-resonance instability. A similar drift-resonance process should occur ubiquitously in collisionless plasma systems. One specific example is the "fishbone" instability in fusion plasma devices. In addition, our observations have important implications for the long-standing mysterious origin of Giant Pulsations.

  4. Nonambipolarity, orthogonal conductivity, poloidal flow, and torque

    SciTech Connect

    Hulbert, G.W.; Perkins, F.W.

    1989-02-01

    Nonambipolar processes, such as neutral injection onto trapped orbits or ripple-diffusion loss of ..cap alpha..-particles, act to charge a plasma. A current j/sub r/ across magnetic surfaces must arise in the bulk plasma to maintain charge neutrality. An axisymmetric, neoclassical model of the bulk plasma shows that these currents are carried by the ions and exert a j/sub r/B/sub theta/R/c torque in the toroidal direction. A driven poloidal flow V/sub theta/ = E/sub r/'c/B must also develop. The average current density is related to the radial electric field E/sub r/' = E/sub r/ + v/sub /phi//B/sub theta//c in a frame moving with the plasma via the orthogonal conductivity = sigma/sub /perpendicular//E/sub r/', which has the value sigma/sub /perpendicular// = (1.65epsilon/sup 1/2/)(ne/sup 2/..nu../sub ii//M..cap omega../sub theta//sup 2/) in the banana regime. If an ignited plasma loses an appreciable fraction ..delta.. of its thermonuclear ..cap alpha..-particles by banana ripple diffusion, then the torque will spin the plasma to sonic rotation in a time /tau//sub s/ approx. 2/tau//sub E//..delta.., /tau//sub E/ being the energy confinement time. 10 refs., 1 fig.

  5. Neoclassical Poloidal and Toroidal Velocities of Impurity Ions

    NASA Astrophysics Data System (ADS)

    Wong, S. K.; Chan, V. S.; Solomon, W. M.

    2008-11-01

    The poloidal and toroidal velocities of impurity ions in a two-ion species plasma for large aspect ratio circular flux surfaces are calculated in the banana and Pfirsch-Schulter regimes of neoclassical theory. The toroidal velocity is allowed to be comparable to the thermal speed of the impurity ions. Closed form expressions are obtained for these velocities in terms of the radial electric field as well as density and temperature gradients. The standard kinetic derivation adopted is compared with the moment approach to the same problems in the case of small toroidal velocities. Comparisons of the calculated poloidal velocity with experimental observations in DIII-D [1] show improved agreement due to the allowance of larger toroidal flows. 6pt [1] W.M. Solomon, Phys. Plasmas 13, 056116 (2006).

  6. Terrace retro-reflector array for poloidal polarimeter on ITER.

    PubMed

    Imazawa, R; Kawano, Y; Ono, T; Kusama, Y

    2011-02-01

    A new concept of a terrace retro-reflector array (TERRA) as part of the poloidal polarimeter for ITER is proposed in this paper. TERRA reflects a laser light even from a high incident angle in the direction of the incident-light path, while a conventional retro-reflector array cannot. Besides, TERRA can be installed in a smaller space than a corner-cube retro-reflector. In an optical sense, TERRA is equivalent to a Littrow grating, the blaze angle of which varies, depending on the incident angle. The reflected light generates a bright and dark fringe, and the bright fringe is required to travel along the incident-light path to achieve the objects of laser-aided diagnostics. In order to investigate the propagation properties of laser light reflected by TERRA, we have developed a new diffraction formula. Conditions for the propagation of the bright fringe in the direction of the incident light have been obtained using the Littrow grating model and have been confirmed in a simulation applying the new diffraction formula. Finally, we have designed laser transmission optics using TERRA for the ITER poloidal polarimeter and have calculated the light propagation of the system. The optical design obtains a high transmission efficiency, with 88.6% of the incident power returned. These results demonstrate the feasibility of applying TERRA to the ITER poloidal polarimeter.

  7. Simultaneous poloidal measurements using new magnetically driven reciprocating probes in COMPASS

    NASA Astrophysics Data System (ADS)

    Dejarnac, R.; Gunn, J. P.; Dimitrova, M.; Hron, M.; Panek, R.; Pascal, J.-Y.; Saragosti-Chausy, C.; Tamain, P.; the COMPASS Team

    2016-03-01

    Particles and heat transport in the scrape-off layer (SOL) of tokamaks is not yet fully understood. COMPASS is a small-size tokamakp where the edge plasma is well diagnosed in view of studying the competition between the parallel and the cross-field transport in the SOL. In order to better characterize SOL dynamics, in particular the poloidal asymmetry of the main parameters' radial profiles, two new in-situ magnetically driven reciprocating manipulators have been recently installed in COMPASS. These manipulators, the so-called pecker probes, are two additional poloidal measurement points to the existing two (vertical and horizontal) reciprocating manipulators. The pecker probes are located at the low field side of COMPASS at ±47.5o with respect to the outer mid-plane and are equipped with identical tunnel probe heads, providing simultaneous measurements of the ion saturation current density Jsat, the electron temperature Te and the parallel Mach number M// with high temporal resolution. In this paper, a detailed description of the pecker probe system in COMPASS is described and first measurements are presented.

  8. Modular tokamak magnetic system

    DOEpatents

    Yang, Tien-Fang

    1988-01-01

    A modular tokamak system comprised of a plurality of interlocking moldules. Each module is comprised of a vacuum vessel section, a toroidal field coil, moldular saddle coils which generate a poloidal magnetic field and ohmic heating coils.

  9. A novel flexible field-aligned coordinate system for tokamak edge plasma simulation

    NASA Astrophysics Data System (ADS)

    Leddy, J.; Dudson, B.; Romanelli, M.; Shanahan, B.; Walkden, N.

    2017-03-01

    Tokamak plasmas are confined by a magnetic field that limits the particle and heat transport perpendicular to the field. Parallel to the field the ionised particles can move freely, so to obtain confinement the field lines are ;closed; (i.e. form closed surfaces of constant poloidal flux) in the core of a tokamak. Towards, the edge, however, the field lines intersect physical surfaces, leading to interaction between neutral and ionised particles, and the potential melting of the material surface. Simulation of this interaction is important for predicting the performance and lifetime of future tokamak devices such as ITER. Field-aligned coordinates are commonly used in the simulation of tokamak plasmas due to the geometry and magnetic topology of the system. However, these coordinates are limited in the geometry they allow in the poloidal plane due to orthogonality requirements. A novel 3D coordinate system is proposed herein that relaxes this constraint so that any arbitrary, smoothly varying geometry can be matched in the poloidal plane while maintaining a field-aligned coordinate. This system is implemented in BOUT++ and tested for accuracy using the method of manufactured solutions. A MAST edge cross-section is simulated using a fluid plasma model and the results show expected behaviour for density, temperature, and velocity. Finally, simulations of an isolated divertor leg are conducted with and without neutrals to demonstrate the ion-neutral interaction near the divertor plate and the corresponding beneficial decrease in plasma temperature.

  10. Prototype detectors for measuring poloidal magnetic flux with an ion beam probe

    NASA Astrophysics Data System (ADS)

    Crowley, T. P.; Demers, D. R.; Fimognari, P. J.; Kile, T. D.

    2016-10-01

    Development of a detector and associated techniques to determine the localized magnetic flux, and therefore poloidal magnetic field and current density profile, in an axisymmetric plasma device is underway. This will provide invaluable information on equilibrium, transport and stability studies of fusion plasmas. A singly charged ion beam is injected into the plasma and the detector located outside the plasma measures doubly charged ions created within a cm-scale sample volume of the plasma. The ions are split into beamlets at the detector. The toroidal angle of the beam's velocity is determined by measuring the fraction of the beamlets that strike detection plates and wires. The corresponding angle is used to determine the beam's toroidal velocity component. Due to canonical momentum conservation, that toroidal velocity is proportional to the poloidal flux function in the sample volume. We have built several prototype detectors and measured the angle of a 45 keV potassium ion beam. The cross-section of the plasma that can be studied will be maximized and system costs will be minimized if the detector has a direct view of the plasma and is operated close to it. However, this subjects the detector to noise due to UV-induced photoelectrons and plasma particles. We have conducted experiments that demonstrate reductions of this noise to facilitate measurement of ion beam signals. Experimental and design results will be presented. This work is supported by US DoE Award No. DE-SC0006077.

  11. Poloidal asymmetries in edge transport barriersa)

    NASA Astrophysics Data System (ADS)

    Churchill, R. M.; Theiler, C.; Lipschultz, B.; Hutchinson, I. H.; Reinke, M. L.; Whyte, D.; Hughes, J. W.; Catto, P.; Landreman, M.; Ernst, D.; Chang, C. S.; Hager, R.; Hubbard, A.; Ennever, P.; Walk, J. R.

    2015-05-01

    Measurements of impurities in Alcator C-Mod indicate that in the pedestal region, significant poloidal asymmetries can exist in the impurity density, ion temperature, and main ion density. In light of the observation that ion temperature and electrostatic potential are not constant on a flux surface [Theiler et al., Nucl. Fusion 54, 083017 (2014)], a technique based on total pressure conservation to align profiles measured at separate poloidal locations is presented and applied. Gyrokinetic neoclassical simulations with XGCa support the observed large poloidal variations in ion temperature and density, and that the total pressure is approximately constant on a flux surface. With the updated alignment technique, the observed in-out asymmetry in impurity density is reduced from previous publishing [Churchill et al., Nucl. Fusion 53, 122002 (2013)], but remains substantial ( n z , H / n z , L ˜ 6 ). Candidate asymmetry drivers are explored, showing that neither non-uniform impurity sources nor localized fluctuation-driven transport are able to explain satisfactorily the impurity density asymmetry. Since impurity density asymmetries are only present in plasmas with strong electron density gradients, and radial transport timescales become comparable to parallel transport timescales in the pedestal region, it is suggested that global transport effects relating to the strong electron density gradients in the pedestal are the main driver for the pedestal in-out impurity density asymmetry.

  12. Test data from the US-Demonstration Poloidal Coil experiment

    SciTech Connect

    Painter, T.A.; Steeves, M.M.; Takayasu, M.; Gung, C.; Hoenig, M.O.; Tsuji, H.; Ando, T.; Hiyama, T.; Takahashi, Y.; Nishi, M.; Yoshida, K.; Okuno, K.; Nakajima, H.; Kato, T.; Sugimoto, M.; Isono, T.; Kawano, K.; Koizumi, N.; Osikiri, M.; Hanawa, H.; Ouchi, H.; Ono, M.; Ishida, H.; Hiue, H.; Yoshida, J.; Kamiyauchi, Y.; Ouchi, T.; Tajiri, F.; Kon, Y.; Shimizu, H.; Matsuzaki, Y.; Oomori, S.; Tani, T.; Oomori, K.; Terakado, T.; Yagyu, J.; Oomori, H.

    1992-01-01

    The US Demonstration Poloidal Field Coil (US-DPC) experiment took place successfully at the Japan Atomic Energy Research Institute (JAERI) in late 1990. The 8 MJ niobium-tin coil was leak tight; it performed very well in DC tests; it performed well in AC tests, achieving approximately 70% of its design goal. An unexpected ramp-rate barrier at high currents was identified. The barrier could not be explored in the regime of higher fields and slower ramp rates due to limitations of the background-field coils. This document presents the results of the experiment with as little editing as possible. The coil, conductor, and operating conditions are given. The intent is to present data in a form that can be used by magnet analysts and designers.

  13. Comparison of Poloidal Velocity Meassurements to Neoclassical Theory on the National Spherical Torus Experiment

    SciTech Connect

    Bell, R E; Kaye, S M; Kolesnikov, R A; LeBlance, B P; Rewolldt, G; Wang, W X

    2010-04-07

    Knowledge of poloidal velocity is necessary for the determination of the radial electric field, Er, which along with its gradient is linked to turbulence suppression and transport barrier formation. Recent measurements of poloidal flow on conventional tokamaks have been reported to be an order of magnitude larger than expected from neoclassical theory. In contrast, recent poloidal velocity measurements on the NSTX spherical torus [S. M. Kaye et al., Phys. Plasmas 8, 1977 (2001)] are near or below neoclassical estimates. A novel charge exchange recombination spectroscopy diagnostic is used, which features active and passive sets of up/down symmetric views to produce line-integrated poloidal velocity measurements that do not need atomic physics corrections. Local profiles are obtained with an inversion. Poloidal velocity measurements are compared with neoclassical values computed with the codes NCLASS [W. A. Houlberg et al., Phys. Plasmas 4, 3230 (1997)] and GTC-Neo [W. X. Wang, et al., Phys. Plasmas 13, 082501 (2006)], which has been updated to handle impurities. __________________________________________________

  14. Geodesic acoustic modes with poloidal mode couplings ad infinitum

    NASA Astrophysics Data System (ADS)

    Singh, Rameswar; Gürcan, Ö. D.

    2017-02-01

    Geodesic acoustic modes (GAMs) are studied including all poloidal mode (m) couplings within a drift reduced Braginskii framework. An exact analytical formula for GAM frequency is given within the toroidal Hasegawa Mima model with the full finite larmor radius effect and poloidal mode couplings ad infinitum using a scalar continued fraction formulation, which results from reduction of the semi-infinite chain of interactions that is obtained from the nearest neighbor coupling pattern due to geodesic curvature. This pattern can be described by a semi-infinite chain model of the GAM with the mode-mode coupling matrix elements proportional to the radial wave number kr. In the more general case of multi-field description of the GAM, the infinite chain can be reduced to a renormalized bi-nodal chain with a matrix continued fraction formulation. The convergence study of the linear GAM dispersion with respect to kr and the m-spectra confirms that the coupling beyond m = 1 is sustained only when kr ≠ 0 and the higher m couplings become important with increasing kr and increasing ion to electron temperature ratio τi.

  15. A poloidal section neutron camera for MAST upgrade

    SciTech Connect

    Sangaroon, S.; Weiszflog, M.; Cecconello, M.; Conroy, S.; Ericsson, G.; Wodniak, I.; Keeling, D.; Turnyanskiy, M. [EURATOM Collaboration: MAST Team

    2014-08-21

    The Mega Ampere Spherical Tokamak Upgrade (MAST Upgrade) is intended as a demonstration of the physics viability of the Spherical Tokamak (ST) concept and as a platform for contributing to ITER/DEMO physics. Concerning physics exploitation, MAST Upgrade plasma scenarios can contribute to the ITER Tokamak physics particularly in the field of fast particle behavior and current drive studies. At present, MAST is equipped with a prototype neutron camera (NC). On the basis of the experience and results from previous experimental campaigns using the NC, the conceptual design of a neutron camera upgrade (NC Upgrade) is being developed. As part of the MAST Upgrade, the NC Upgrade is considered a high priority diagnostic since it would allow studies in the field of fast ions and current drive with good temporal and spatial resolution. In this paper, we explore an optional design with the camera array viewing the poloidal section of the plasma from different directions.

  16. The poloidal distribution of turbulent fluctuations in the Mega-Ampere Spherical Tokamak

    SciTech Connect

    Antar, G.Y.; Counsell, G.; Ahn, J.-W.; Yang, Y.; Price, M.; Tabasso, A.; Kirk, A.

    2005-03-01

    Recently, it was shown that intermittency observed in magnetic fusion devices is caused by large-scales events with high radial velocity reaching about 1/10th of the sound speed (called avaloids or blobs) [G. Antar et al., Phys. Rev. Lett. 87 065001 (2001)]. In the present paper, the poloidal distribution of turbulence is investigated on the Mega-Ampere Spherical Tokamak [A. Sykes et al., Phys. Plasmas 8 2101 (2001)]. To achieve our goal, target probes that span the divertor strike points are used and one reciprocating probe at the midplane. Moreover, a fast imaging camera that can reach 10 {mu}s exposure time looks tangentially at the plasma allowing us to view a poloidal cut of the plasma. The two diagnostics allow us to have a rather accurate description of the particle transport in the poloidal plane for L-mode discharges. Turbulence properties at the low-field midplane scrape-off layer are discussed and compared to other poloidal positions. On the low-field target divertor plates, avaloids bursty signature is not detected but still intermittency is observed far from the strike point. This is a consequence of the field line expansion which transforms a structure localized in the poloidal plane into a structure which expands over several tens of centimeters at the divertor target plates. Around the X point and in the high-field side, however, different phenomena enter into play suppressing the onset of convective transport generation. No signs of intermittency are observed in these regions. Accordingly, like 'normal' turbulence, the onset of convective transport is affected by the local magnetic curvature and shear.

  17. The poloidal distribution of turbulent fluctuations in the Mega-Ampère Spherical Tokamak

    NASA Astrophysics Data System (ADS)

    Antar, G. Y.; Counsell, G.; Ahn, J.-W.; Yang, Y.; Price, M.; Tabasso, A.; Kirk, A.

    2005-03-01

    Recently, it was shown that intermittency observed in magnetic fusion devices is caused by large-scales events with high radial velocity reaching about 1/10th of the sound speed (called avaloids or blobs) [G. Antar et al., Phys. Rev. Lett. 87 065001 (2001)]. In the present paper, the poloidal distribution of turbulence is investigated on the Mega-Ampère Spherical Tokamak [A. Sykes et al., Phys. Plasmas 8 2101 (2001)]. To achieve our goal, target probes that span the divertor strike points are used and one reciprocating probe at the midplane. Moreover, a fast imaging camera that can reach 10μs exposure time looks tangentially at the plasma allowing us to view a poloidal cut of the plasma. The two diagnostics allow us to have a rather accurate description of the particle transport in the poloidal plane for L-mode discharges. Turbulence properties at the low-field midplane scrape-off layer are discussed and compared to other poloidal positions. On the low-field target divertor plates, avaloids bursty signature is not detected but still intermittency is observed far from the strike point. This is a consequence of the field line expansion which transforms a structure localized in the poloidal plane into a structure which expands over several tens of centimeters at the divertor target plates. Around the X point and in the high-field side, however, different phenomena enter into play suppressing the onset of convective transport generation. No signs of intermittency are observed in these regions. Accordingly, like "normal" turbulence, the onset of convective transport is affected by the local magnetic curvature and shear.

  18. Impurity poloidal asymmetries and plasma rotation in the PDX Tokamak

    NASA Astrophysics Data System (ADS)

    Brau, K.

    Vertical poloidal asymmetries of carbon and oxygen in the PDX Tokamak were monitored under a variety of discharge conditions in circular plasmas. Near the edge of the plasma and in the region beyond the limiter, the asymmetries appear to be caused by local impurity recycling, variations in the length of the emitting region, and effects due to vertical ion drifts. In the case of C V impurities, the sign and magnitude of the asymmetry is in qualitative agreement with the predictions of a quasi-neoclassical fluid model of impurity transport. A two dimensional computer code is used to simulate different models of poloidal asymmetries, including: (1) poloidally asymmetric source function, (2) charge exchange recombination with neutral hydrogen, (3) poloidally asymmetric electron ensity and temperature profiles, (4) poloidally varying anomalous radial diffusion coefficient, and (5) the quasi-neoclassical fluid model.

  19. Innovations in Quasi-Poloidal Stellarator Design

    NASA Astrophysics Data System (ADS)

    Nelson, B. E.; Lyon, J. F.; Freudenberg, K. D.; Fogarty, P. J.; Benson, R. D.; Madhukar, M.

    2006-10-01

    The Quasi-Poloidal Stellarator (QPS) is being developed with very low plasma aspect ratio, 1/2-1/4 that of existing stellarators. Design innovation is driven by both the complex 3-D geometry and the need for reduced cost and risk in fabrication, so QPS differs significantly in design and construction from other toroidal devices. An internally cooled, compacted cable conductor consisting of stranded copper filaments wound around an internal copper cooling tube was developed that can be wound into complex 3-D shapes. This conductor is wound directly onto the complex, highly accurate, stainless steel coil winding forms. Simplified coil winding procedures lead to faster fabrication and reduced technical risk. A full-size prototype of the largest and most complex of the winding forms has been cast using a patternless process (machined sand molds) and a high-temperature pour, which resulted in <1/10 the major weld repairs of similar sand castings using conventional patterns, and machined to high precision. A vacuum-tight cover is welded over each coil pack and a high-temperature cyanate ester resin is used for vacuum pressure impregnation of the coils because it has several important advantages over the usual epoxy. The completed coils are then installed in an external vacuum vessel.

  20. Neoclassical ion heat flux and poloidal flow in a tokamak pedestal

    NASA Astrophysics Data System (ADS)

    Kagan, Grigory; Catto, Peter J.

    2010-05-01

    In the core of a tokamak, turbulent transport normally dominates over neoclassical. The situation could be different in a high confinement (or H) mode pedestal, where the former may be suppressed by a strongly sheared equilibrium electric field. On the other hand, this very field makes conventional neoclassical results inapplicable in the pedestal by significantly modifying ion drift orbits. We present the first calculation of the banana regime neoclassical ion heat flux and poloidal flow in the pedestal accounting for the strong E × B drift inherent to this tokamak region. Interestingly, we find that due to the electric field the pedestal poloidal ion flow can change its direction as compared with its core counterpart. This result elucidates the discrepancy between the conventional banana regime predictions and recent experimental measurements of the impurity flow performed at Alcator C-Mod.

  1. High poloidal beta equilibria in TFTR limited by a natural inboard poloidal field null

    SciTech Connect

    Sabbagh, S.A.; Gross, R.A.; Mauel, M.E.; Navratil, G.A. . Dept. of Applied Physics); Bell, M.G.; Bell, R.; Bitter, M.; Bretz, N.L.; Budny, R.V.; Bush, C.E.; Chance, M.S.; Efthimion, P.C.; Fredrickson, E.D.; Hatcher, R.; Hawryluk, R.J.; Hirshman, S.P.; Janos, A.C.; Jardin, S.C.; Jassby, D.L.; Manickam, J.; McCune, D.C.; McGuire, K.M.; Medley, S.S.; Mueller, D.; Nagayama, Y.; Ow

    1991-07-01

    Recent operation of the Tokamak Fusion Test Reactor TFTR, has produced plasma equilibria with values of {Lambda} {triple bond} {beta}{sub p eq} + l{sub i}/2 as large as 7, {epsilon}{beta}{sub p dia} {triple bond} 2{mu}{sub 0}{epsilon}/{much lt}B{sub p}{much gt}{sup 2} as large as 1.6, and Troyon normalized diamagnetic beta, {beta}{sub N dia} {triple bond} 10{sup 8}<{beta}{sub t}{perpendicular}>aB{sub 0}/I{sub p} as large as 4.7. When {epsilon}{beta}{sub p dia} {approx gt} 1.25, a separatrix entered the vacuum chamber, producing a naturally diverted discharge which was sustained for many energy confinement times, {tau}{sub E}. The largest values of {epsilon}{beta}{sub p} and plasma stored energy were obtained when the plasma current was ramped down prior to neutral beam injection. The measured peak ion and electron temperatures were as large as 24 keV and 8.5 keV, respectively. Plasma stored energy in excess of 2.5 MJ and {tau}{sub E} greater than 130 msec were obtained. Confinement times of greater than 3 times that expected from L-mode predictions have been achieved. The fusion power gain. Q{sub DD}, reached a values of 1.3 {times} 10{sup {minus}3} in a discharge with I{sub p} = 1 MA and {epsilon}{beta}{sub p dia} = 0.85. A large, sustained negative loop voltage during the steady state portion of the discharge indicates that a substantial non-inductive component of I{sub p} exists in these plasmas. Transport code analysis indicates that the bootstrap current constitutes up to 65% of I{sup p}. Magnetohydrodynamic (MHD) ballooning stability analysis shows that while these plasmas are near, or at the {beta}{sub p} limit, the pressure gradient in the plasma core is in the first region of stability to high-n modes. 24 refs., 10 figs.

  2. The structure and poloidal dynamics of blob filaments in TJ-K

    NASA Astrophysics Data System (ADS)

    Garland, S.; Fuchert, G.; Ramisch, M.; Hirth, T.

    2016-04-01

    Relatively dense, field-aligned, filament-like structures (blobs) have been observed to propagate radially and poloidally through the scrape-off layer (SOL) in magnetically confined fusion plasmas, and contribute significantly to SOL transport. A detailed understanding of blob structure and dynamics, and their dependence on magnetic field geometry, is important in magnetic confinement physics for the prediction of heat loads on reactor wall facing components, as well as for understanding plasma confinement and neutral particle recycling. Experimentally deduced centre of mass poloidal blob velocity components, obtained using the conditional averaging technique, have been compared to an analytical blob model which has been simplified to express blob velocity in terms of the magnetic field curvature vector. Background flows are not incorporated into the analytical model, and must be added in to obtain good agreement with the experimental data. In addition, the 3D structure of blobs in TJ-K has been investigated using the conditional average of density fluctuations in two toroidally separated poloidal planes. Blobs are observed to be aligned to a flux tube near to the last closed flux surface, in the blob birth region. However at positions further along the blob trajectory, the structures do not deform according to the magnetic shear, rather they remain rigid, and retain their original form.

  3. Experimental study on feedback control system of plasma position

    SciTech Connect

    Abe, M.; Otsuka, M.; Nishi, M.; Kanamori, T.; Kobayashi, T.; Uchikawa, S.

    1981-01-01

    Performance of the feedback control system for the horizontal plasma position in the small shell-less tokamak, HT-1, has been studied numerically and experimentally. Emphasis was put on verifying the validity of coupling parameter evaluation methods for poloidal field coils and structures such as the vaccum vessel and the transformer iron core. The effect of the iron core on the poloidal field distribution was analyzed numerically. Mutual inductances between poloidal field coils and structures were obtained from the calculated eddy currents. Using these calculated parameters, the indicial response of the feedback control loop was studied analytically. Good agreement between calculations and experiments was obtained.

  4. Experimental identification of the kink instability as a poloidal flux amplification mechanism for coaxial gun spheromak formation.

    PubMed

    Hsu, S C; Bellan, P M

    2003-05-30

    The magnetohydrodynamic kink instability is observed and identified experimentally as a poloidal flux amplification mechanism for coaxial gun spheromak formation. Plasmas in this experiment fall into three distinct regimes which depend on the peak gun current to magnetic flux ratio, with (I) low values resulting in a straight plasma column with helical magnetic field, (II) intermediate values leading to kinking of the column axis, and (III) high values leading immediately to a detached plasma. Onset of column kinking agrees quantitatively with the Kruskal-Shafranov limit, and the kink acts as a dynamo which converts toroidal to poloidal flux. Regime II clearly leads to both poloidal flux amplification and the development of a spheromak configuration.

  5. The impact of poloidal asymmetries on tungsten transport in the core of JET H-mode plasmas

    SciTech Connect

    Angioni, C.; Pütterich, T.; Bilato, R.; Casson, F. J.; Giroud, C.; Mantica, P.; Helander, P.

    2015-05-15

    Recent progress in the understanding and prediction of the tungsten behaviour in the core of JET H-mode plasmas with ITER-like wall is presented. Particular emphasis is given to the impact of poloidal asymmetries of the impurity density. In particular, it is shown that the predicted reduction of temperature screening induced by the presence of low field side localization of the tungsten density produced by the centrifugal force is consistent with the observed tungsten behaviour in a JET discharge in H-mode baseline scenario. This provides first evidence of the role of poloidal asymmetries in reducing the strength of temperature screening. The main differences between plasma parameters in JET baseline and hybrid scenario discharges which affect the impact of poloidally asymmetric density on the tungsten radial transport are identified. This allows the conditions by which tungsten accumulation can be avoided to be more precisely defined.

  6. Bright field illumination system

    NASA Technical Reports Server (NTRS)

    Huber, Edward D. (Inventor)

    1998-01-01

    A Bright Field Illumination system for inspecting a range of characteristically different kinds of defects, depressions, and ridges in a selected material surface. The system has an illumination source placed near a first focus of an elliptical reflector. In addition, a camera facing the inspected area is placed near the illumination source and the first focus. The second focus of the elliptical reflector is located at a distance approximately twice the elliptical reflector's distance above the inspected surface. The elliptical reflector directs the light from the source onto the inspected surface. Due to the shape of the elliptical reflector, light that is specularly reflected from the inspected surface is directed into the camera is which located at the position of the reflected second focus of the ellipse. This system creates a brightly lighted background field against which damage sites appear as high contrast dark objects which can be easily detected by a person or an automated inspection system. In addition, the Bright Field Illumination system and method can be used in combination with a vision inspection system providing for multiplexed illumination and data handling of multiple kinds of surface characteristics including abrupt and gradual surface variations and differences between measured characteristics of different kinds and prior instruments.

  7. Poloidal rotation and its relation to the potential vorticity flux

    SciTech Connect

    McDevitt, C. J.; Diamond, P. H.; Guercan, Oe. D.; Hahm, T. S.

    2010-11-15

    A kinetic generalization of a Taylor identity appropriate to a strongly magnetized plasma is derived. This relation provides an explicit link between the radial mixing of a four-dimensional (4D) gyrocenter fluid and the poloidal Reynolds stress. This kinetic analog of a Taylor identity is subsequently utilized to link the turbulent transport of poloidal momentum to the mixing of potential vorticity. A quasilinear calculation of the flux of potential vorticity is carried out, yielding diffusive, turbulent equipartition, and thermoelectric convective components. Self-consistency is enforced via the quasineutrality relation, revealing that for the case of a stationary small amplitude wave population, deviations from neoclassical predictions of poloidal rotation can be closely linked to the growth/damping profiles of the underlying drift wave microturbulence.

  8. Impact of poloidal convective cells on momentum flux in tokamaks

    NASA Astrophysics Data System (ADS)

    Garbet, X.; Asahi, Y.; Donnel, P.; Ehrlacher, C.; Dif-Pradalier, G.; Ghendrih, P.; Grandgirard, V.; Sarazin, Y.

    2017-01-01

    Radial fluxes of parallel momentum due to E× B and magnetic drifts are shown to be correlated in tokamak plasmas. This correlation comes from the onset of poloidal convective cells generated by turbulence. The entire process requires a symmetry breaking mechanism, e.g. a mean shear flow. An analytical calculation shows that anti-correlation between the poloidal and parallel components of the turbulent Reynolds stress results in anti-correlation of the fluxes of parallel momentum generated by E× B and curvature drifts.

  9. Dynamics of poloidal flows in enhanced reverse shear bifurcation

    SciTech Connect

    Srinivasan, R.; Avinash, K.

    2005-07-15

    A simple reduced enhanced reverse shear (RERS) model is constructed to study the dynamics of poloidal flows during the ERS transition. This model predicts that a reversal of poloidal flow shear occurs just prior to the transition, as seen in experiment [R. E. Bell et al., Phys. Rev. Lett. 81, 1429 (1998)]. This transition front propagates until the radial location where the safety factor (q) is minimum and becomes locked there due to insufficient input power to overcome the threshold requirement for the bifurcation. This study also reveals that there can be many routes to ERS transition depending upon various tunable parameters.

  10. Oil field management system

    DOEpatents

    Fincke, James R.

    2003-09-23

    Oil field management systems and methods for managing operation of one or more wells producing a high void fraction multiphase flow. The system includes a differential pressure flow meter which samples pressure readings at various points of interest throughout the system and uses pressure differentials derived from the pressure readings to determine gas and liquid phase mass flow rates of the high void fraction multiphase flow. One or both of the gas and liquid phase mass flow rates are then compared with predetermined criteria. In the event such mass flow rates satisfy the predetermined criteria, a well control system implements a correlating adjustment action respecting the multiphase flow. In this way, various parameters regarding the high void fraction multiphase flow are used as control inputs to the well control system and thus facilitate management of well operations.

  11. Transverse field focused system

    DOEpatents

    Anderson, Oscar A.

    1986-01-01

    A transverse field focused (TFF) system for transport or acceleration of an intense sheet beam of negative ions in which a serial arrangement of a plurality of pairs of concentric cylindrical-arc electrodes is provided. Acceleration of the sheet beam can be achieved by progressively increasing the mean electrode voltage of successive electrode pairs. Because the beam is curved by the electrodes, the system can be designed to transport the beam through a maze passage which is baffled to prevent line of sight therethrough. Edge containment of the beam can be achieved by shaping the side edges of the electrodes to produce an electric force vector directed inwardly from the electrode edges.

  12. Multi-channel poloidal correlation reflectometry on experimental advanced superconducting tokamak

    NASA Astrophysics Data System (ADS)

    Qu, H.; Zhang, T.; Han, X.; Xiang, H. M.; Wen, F.; Geng, K. N.; Wang, Y. M.; Kong, D. F.; Cai, J. Q.; Huang, C. B.; Gao, Y.; Gao, X.; Zhang, S.

    2016-11-01

    A new multi-channel poloidal correlation reflectometry is developed at Experimental Advanced Superconducting Tokamak. Eight dielectric resonator oscillators with frequencies of 12.5 GHz, 13.5 GHz, 14.5 GHz, 15 GHz, 15.5 GHz, 16 GHz, 17 GHz, and 18 GHz are used as sources. Signals from the sources are up-converted to V band using active quadruplers and then coupled together. The output waves are launched by one single antenna after passing through a 20 dB directional coupler which can provide the reference signal. Two poloidally separated antennae are installed to receive the reflected waves from plasma. The reference and reflected signals are down-converted by mixing with a quadrupled signal from a phase-locked source with a frequency of 14.2 GHz and the IF signals pass through the filter bank. The resulting signals from the mixers are detected by I/Q demodulators. The setup enables the measurement of density fluctuation at 8 (radial) × 2 (poloidal) spatial points. A coherent mode with an increasing velocity from 50 kHz to 100 kHz is observed by using the system. The mode is located in the steep gradient region of the pedestal.

  13. Multi-channel poloidal correlation reflectometry on experimental advanced superconducting tokamak.

    PubMed

    Qu, H; Zhang, T; Han, X; Xiang, H M; Wen, F; Geng, K N; Wang, Y M; Kong, D F; Cai, J Q; Huang, C B; Gao, Y; Gao, X; Zhang, S

    2016-11-01

    A new multi-channel poloidal correlation reflectometry is developed at Experimental Advanced Superconducting Tokamak. Eight dielectric resonator oscillators with frequencies of 12.5 GHz, 13.5 GHz, 14.5 GHz, 15 GHz, 15.5 GHz, 16 GHz, 17 GHz, and 18 GHz are used as sources. Signals from the sources are up-converted to V band using active quadruplers and then coupled together. The output waves are launched by one single antenna after passing through a 20 dB directional coupler which can provide the reference signal. Two poloidally separated antennae are installed to receive the reflected waves from plasma. The reference and reflected signals are down-converted by mixing with a quadrupled signal from a phase-locked source with a frequency of 14.2 GHz and the IF signals pass through the filter bank. The resulting signals from the mixers are detected by I/Q demodulators. The setup enables the measurement of density fluctuation at 8 (radial) × 2 (poloidal) spatial points. A coherent mode with an increasing velocity from 50 kHz to 100 kHz is observed by using the system. The mode is located in the steep gradient region of the pedestal.

  14. Shock and soliton structures induced by poloidal flow in tokamaks

    NASA Astrophysics Data System (ADS)

    Taniuti, T.; Watanabe, K.; Ishii, Y.; Wakatani, M.

    1991-04-01

    When poloidal flow velocity, Up, becomes close to epsilon C sub s in tokamaks, fluid motion inside the flux surface is governed by a forced KdV equation in the small dissipation limit, where epsilon is an inverse aspect ratio and C sub s is a sound velocity. This implies that a stationary soliton structure appears at the inside region of toroidal plasma or theta is approx. pi, where theta is a poloidal angle. In the limit of large dissipation a forced Burgers equation is more appropriate. This case corresponds to an appearance of shock structure. When an averaged poloidal flow velocity is very close to epsilon C sub s, a shock may be seen in the outer region of toroidal plasma or theta is approx. 0. With the increase of the absolute vakue of (Up-epsilon C sub s) the shock position moves from theta is approx. 0 to theta is approx. pi. Recent tokamak experiments show the existence of poloidal flow with Up is approx. epsilon C sub s in the transition phase from L mode to H mode. Implications of the results in the experiment are discussed.

  15. Neoclassical ion heat flux and poloidal flow in a tokamak pedestal

    NASA Astrophysics Data System (ADS)

    Kagan, Grigory; Catto, Peter J.

    2009-11-01

    In the core of a tokamak, neoclassical transport normally dominates over classical while itself being dominated by turbulent transport. The situation may be different in a high confinement (or H) mode pedestal, where the latter is effectively suppressed by a strongly sheared equilibrium electric field. On the other hand, this very field makes conventional neoclassical results inapplicable in the pedestal by significantly modifying ion drift orbits. We present the first calculation of the banana regime neoclassical ion heat flux and poloidal flow in the pedestal accounting for the strong ExB drift inherent to this tokamak region. Interestingly, the fact that ion heat conductivity depends on the local values of the electric field and its shear allows us to hypothesize about possible shapes of the global electric field and density profiles in the pedestal. We also find that due to the electric field the pedestal poloidal ion flow is likely to change its direction as compared to its core counterpart. This result elucidates the discrepancy between the conventional banana regime predictions and recent experimental measurements of the impurity flow performed at Alcator C-Mod.

  16. The interaction of high-m guided poloidal alfven waves with magnetospheric electrons and the ionosphere

    NASA Astrophysics Data System (ADS)

    Rankin, R.; Sydorenko, D.

    2014-12-01

    Poloidal mode Alfven waves are often generated in Earth's magnetosphere following interplanetary shocks and/or pressure pulses acting on the magnetopause. These disturbances can excite resonant field line oscillations with frequencies in the mHz range by launching fast mode waves that couple energy to field line resonances. This direct action of the solar wind on the magnetosphere can perhaps explain waves with relatively small azimuthal wavenumbers (m), but not the observed range of waves with m~40-50 on L-shells around 5 or 6. These waves are strongly guided along geomagnetic field lines to the ionosphere, and are generally thought to particle driven, e.g., as a result of bounce-resonance wave-particle interactions following activation of the ring current. This is not the only possible source mechanism as there is evidence of wave generation before the ring current has reacted significantly to shock passage. Putting aside the source mechanism, high-m poloidal modes with strong east west directed electric fields are important primarily because they can elevate differential energy flux for electron energies in the range of 100's of keV to several MeV. In this paper we use observations of guided poloidal mode Alfven waves to constrain a ULF wave model that describes not only how waves evolve on geomagnetic field lines, but also their interaction with a dynamic height-resolved ionosphere. The ionosphere and neutral atmosphere are specified in the model using the IRI and MSIS models. These regions react to waves and precipitation through heating and cooling, ionization, recombination, and chemical reactions. We present detailed results of the interaction of a poloidal wave observed by the Eiscat radar, and demonstrate that the model used can reproduce all aspects of the radar observations. We consider mechanisms for pulsed precipitation accompanying this wave, which causes a phase difference of ~90 degrees between observed temperature and density spikes. We also

  17. Plasma boundary and SOL studies of ECH-plasmas in TJ-II stellarator with diagnosed mobile poloidal limiters

    NASA Astrophysics Data System (ADS)

    de la Cal, E.; Brañas, B.; Tabarés, F. L.; Tafalla, D.; Fraguas, A. L.; Pedrosa, M. A.; Tribaldos, V.; Ascasibar, E.; Herranz, J.; Pastor, I.; TJ-II Team

    2001-03-01

    TJ-II is a medium size (major radius R=1.5 m, average minor plasma radius a<0.2 m, on axis magnetic field B=1 T) helical axis stellarator operating in its first phase with up to 600 kW of ECH power. Two mobile poloidal limiters can control the last closed magnetic surface (LCMS) and diagnose the plasma boundary with a set of Langmuir probes and with CCD-cameras equipped with interference filters. In the described experiments, plasmas with different minor radii interact either with the toroidal limiter or with the mobile poloidal limiters. The electron density and temperature profiles are characterised in the plasma centre, boundary and scape-off layer (SOL) for the different configurations. The global energy for the different configurations is compared and the ratio of the energy confinement time to that obtained by the LHD-scaling-law, seem to be improved when inserting the poloidal limiters. Finally, it is discussed whether the large connection lengths obtained in certain poloidal limiter SOL regions effectively reduce the plasma size, making the definition of the plasma minor radius ambiguous.

  18. Poloidal divertor experiment with applied E vector x B vector/B/sup 2/ drift

    SciTech Connect

    Strait, E J

    1980-05-01

    It has been proposed that the E vector x B vector/B/sup 2/ drift arising from an externally applied electric field could be used in a tokamak or other toroidal device to remove plasma and impurities from the region near the wall and to reduce the amount of plasma striking the wall, either assisting or replacing a conventional magnetic field divertor. A poloidal magnetic divertor (without pumping chamber) was added to the Wisconsin Levitated Toroidal Octupole, and the octupole was operated with a tokamak-like magnetic field configuration (q = 0.7). A radial electric field was applied in the scrape-off zone, causing an E vector x B vector/B/sup 2/ drift with a large poloidal component. This reduced plasma flux reaching the wall of the toroid by up to a factor of 5 beyond the effect of the magnetic divertor, for divertor configurations with both high and low magnetic mirror ratios, in good agreement with a simple theoretical model. Plasma density and density scale length were also reduced in the scrape-off zone, in qualitative agreement with the model. This was not accompanied by any new instabilities in the scrape-off zone, nor by any appreciable degradation of confinement of the central plasma.

  19. Predictions of the poloidal asymmetries and transport frequencies in KSTAR

    SciTech Connect

    Bae, C. Lee, S. G.; Terzolo, L.; Stacey, W. M.

    2014-01-15

    The extended neoclassical rotation theory formulated in Miller flux surface geometry enables unprecedented neoclassical calculations of the poloidal asymmetries in density, rotation velocities, electrostatic potential along the flux surfaces, and of the inertial (Reynolds stress) and gyroviscous transport frequencies, which are strong functions of these asymmetries. This paper presents such calculations of the poloidal asymmetries and non-negligible inertial and gyroviscous transport frequencies in two KSTAR (Korea Superconducting Tokamak Advanced Research) [Kwon et al., Nucl. Fusion 51, 094006 (2011)] Neutral Beam Injection H-mode discharges. The in-out asymmetries in the velocities are an order of magnitude larger than their up-down asymmetries. The magnitudes of the predicted inertial and gyroviscous transport frequencies depend on the magnitudes of the density and velocity asymmetries. The neoclassically predicted density asymmetries are shown to correspond with the reported measurements in tokamaks and the predicted carbon toroidal velocities agree very well with the measurements in KSTAR.

  20. Poloidal velocity of impurity ions in neoclassical theory

    NASA Astrophysics Data System (ADS)

    Wong, S. K.; Chan, V. S.; Solomon, W. M.

    2008-08-01

    A formula for the poloidal velocity of impurity ions in a two-species plasma is derived from neoclassical theory in the banana regime, with corrections from the boundary layer separating the trapped and transiting ions. The formula is applicable to plasmas with toroidal rotations that can approach the thermal speeds of the ions. Using the formula to determine the poloidal velocity of C+6 ions in a recently reported experiment [W. M. Solomon et al., Phys. Plasmas 13, 056116 (2006)] leads to agreement in the direction of the central region when it is otherwise from theories without strong toroidal rotations. Comparisons among these theories are made, demonstrating the degree of uncertainty of theoretical predictions.

  1. Poloidal flow damping with potato orbits in tokamaks

    SciTech Connect

    Shaing, K.C.

    2005-10-01

    The poloidal flow damping rate in the vicinity of the magnetic axis in tokamaks is calculated using the time-dependent plasma viscosity. It is found that the damping rate is of the order of {nu}{sub ii}/f{sub t}{sup 2}, where {nu}{sub ii} is the ion-ion collision frequency, and f{sub t} is the fraction of the trapped potatoes. The corresponding neoclassical polarization or inertia enhancement factor is [1+({sigma}{sub p}q{sup 2}/f{sub t})], where {sigma}{sub p} is a numerical number of the order of unity, and q is the safety factor.

  2. The poloidal distribution of type-III edge localized modes in the Mega-Ampere spherical tokamak (MAST)

    SciTech Connect

    Antar, G.Y.

    2006-05-15

    This article describes the poloidal plasma particle distribution of type-III edge localized modes (ELMs) in the Mega-Ampere spherical tokamak [R.-J. Akers et al., Phys. Plasmas 9, 3919 (2002)]. A fast imaging camera with 10 {mu}s exposure time is used to record the D{sub {alpha}} light coming from the entire poloidal cross section. Furthermore, three sets of probes, triggered at the same time, acquired at 1 MHz, and located at different poloidal, radial, and toroidal locations in the tokamak are used. ELMs are observed to affect the D{sub {alpha}} emission throughout the low-field scrape-off layer; on the high-field side, however, this effect is found to be small. The results obtained by imaging agree with the pointwise measurements using Langmuir probes. The radial propagation is shown to occur at a speed of 250 m/s, whereas the toroidal convection from the top to the bottom of the plasma is shown to be consistent with a transport at the local sound speed. Strong correlation amplitudes are reported among the probes that are poloidally and toroidally separated by several meters. The study of the cross-correlation coefficients as a function of the frequency indicates that this correlation is caused by the low-frequency component of the signal and that the high-frequency part is not correlated. Consequently, the filamentary structures are interpreted as caused by the onset of turbulence during an ELM and do not constitute the ELM itself.

  3. Improved analytical flux surface representation and calculation models for poloidal asymmetries

    NASA Astrophysics Data System (ADS)

    Collart, T. G.; Stacey, W. M.

    2016-05-01

    An orthogonalized flux-surface aligned curvilinear coordinate system has been developed from an up-down asymmetric variation of the "Miller" flux-surface equilibrium model. It is found that the new orthogonalized "asymmetric Miller" model representation of equilibrium flux surfaces provides a more accurate match than various other representations of DIII-D [J. L. Luxon, Nucl. Fusion 42, 614-633 (2002)] discharges to flux surfaces calculated using the DIII-D Equilibrium Fitting tokamak equilibrium reconstruction code. The continuity and momentum balance equations were used to develop a system of equations relating asymmetries in plasma velocities, densities, and electrostatic potential in this curvilinear system, and detailed calculations of poloidal asymmetries were performed for a DIII-D discharge.

  4. Observation of dust torus with poloidal rotation in direct current glow discharge plasma

    SciTech Connect

    Kaur, Manjit Bose, Sayak; Chattopadhyay, P. K. Sharma, Devendra; Ghosh, J.; Saxena, Y. C.

    2015-03-15

    Observation of dust cloud rotation in parallel-plate DC glow discharge plasma is reported here. The experiments are carried out at high pressures (∼130 Pa) with a metallic ring placed on the lower electrode (cathode). The dust cloud rotates poloidally in the vertical plane near the cathode surface. This structure is continuous toroidally. Absence of magnetic field rules out the possibility of E × B induced ion flow as the cause of dust rotation. The dust rotational structures exist even with water cooled cathode. Therefore, temperature gradient driven mechanisms, such as thermophoretic force, thermal creep flow, and free convection cannot be causing the observed dust rotation. Langmuir probe measurement reveals the existence of a sharp density gradient near the location of the rotating dust cloud. The gradient in the density, giving rise to a gradient in the ion drag force, has been identified as the principal cause behind the rotation of dust particles.

  5. Preliminary skyshine calculations for the Poloidal Diverter Tokamak Experiment

    NASA Astrophysics Data System (ADS)

    Nigg, D. W.; Wheeler, F. J.

    1981-01-01

    A calculational model is presented to estimate the radiation dose, due to the skyshine effect, in the control room and at the site boundary of the Poloidal Diverter Experiment (PDX) facility at Princeton University which requires substantial radiation shielding. The required composition and thickness of a water-filled roof shield that would reduce this effect to an acceptable level is computed, using an efficient one-dimensional model with an Sn calculation in slab geometry. The actual neutron skyshine dose is computed using a Monte Carlo model with the neutron source at the roof surface obtained from the slab Sn calculation, and the capture gamma dose is computed using a simple point-kernel single-scatter method. It is maintained that the slab model provides the exact probability of leakage out the top surface of the roof and that it is nearly as accurate as and much less costly than multi-dimensional techniques.

  6. Poloidal rotation driven by nonlinear momentum transport in strong electrostatic turbulence

    NASA Astrophysics Data System (ADS)

    Wang, Lu; Wen, Tiliang; Diamond, P. H.

    2016-10-01

    Virtually, all existing theoretical works on turbulent poloidal momentum transport are based on quasilinear theory. Nonlinear poloidal momentum flux—< {{\\tilde{v}}r}\\tilde{n}{{\\tilde{v}}θ}> is universally neglected. However, in the strong turbulence regime where relative fluctuation amplitude is no longer small, quasilinear theory is invalid. This is true at the all-important plasma edge. In this work, nonlinear poloidal momentum flux < {{\\tilde{v}}r}\\tilde{n}{{\\tilde{v}}θ}> in strong electrostatic turbulence is calculated using the Hasegawa-Mima equation, and is compared with quasilinear poloidal Reynolds stress. A novel property is that symmetry breaking in fluctuation spectrum is not necessary for a nonlinear poloidal momentum flux. This is fundamentally different from the quasilinear Reynold stress. Furthermore, the comparison implies that the poloidal rotation drive from the radial gradient of nonlinear momentum flux is comparable to that from the quasilinear Reynolds force. Nonlinear poloidal momentum transport in strong electrostatic turbulence is thus not negligible for poloidal rotation drive, and so may be significant to transport barrier formation.

  7. Two-Dimensional MHD Simulations of Tokamak Plasmas with Poloidal Flow

    NASA Astrophysics Data System (ADS)

    Guazzotto, L.; Betti, R.

    2002-11-01

    A two- dimensional MHD code has been developed to simulate the temporal evolution of Tokamak plasmas with an imposed poloidal flow. The code is fully compressible and can resolve the shock structures arising when the poloidal velocity is of the order of the poloidal sound speed (V_θ ˜ Cs B_θ/B) near the plasma edge, where the plasma is cold and the sound speed is low. The poloidal flow is assigned as an initial condition with a velocity profile ranging from subsonic to supersonic near the edge. It is found that a continuous band of shocks is formed near the edge. Such shocks travel poloidally, leaving behind a pedestal structure similar to the one predicted in Ref. 1 [R. Betti and J. P. Freidberg, Phys. Plasmas 7, 2439 (2000)]. Here, the pedestal is defined as a sharp discontinuity in the pressure, temperature, and density profiles. The pedestal height is modulated in the poloidal angle; it is maximum on the outboard side (θ = 0) and minimum on the inboard (θ = π). Furthermore, both poloidal and toroidal flows develop a shear layer at the location of the pedestal. The large velocity shear (both poloidal and toroidal) occurring in the pedestal region is likely to suppress turbulent eddies and reduce anomalous transport. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC03-92SF19460.

  8. Two-dimensional magnetohydrodynamic simulations of poloidal flows in tokamaks and MHD pedestal

    NASA Astrophysics Data System (ADS)

    Guazzotto, L.; Betti, R.

    2011-09-01

    Poloidal rotation is routinely observed in present-day tokamak experiments, in particular near the plasma edge and in the high-confinement mode of operation. According to the magnetohydrodynamic (MHD) equilibrium theory [R. Betti and J. P. Freidberg, Phys. Plasmas 7, 2439 (2000)], radial discontinuities form when the poloidal velocity exceeds the poloidal sound speed (or rather, more correctly, the poloidal magneto-slow speed). Two-dimensional compressible magnetohydrodynamic simulations show that the transonic discontinuities develop on a time scale of a plasma poloidal revolution to form an edge density pedestal and a localized velocity shear layer at the pedestal location. While such an MHD pedestal surrounds the entire core, the outboard side of the pedestal is driven by the transonic discontinuity while the inboard side is caused by a poloidal redistribution of the mass. The MHD simulations use a smooth momentum source to drive the poloidal flow. Soon after the flow exceeds the poloidal sound speed, the density pedestal and the velocity shear layer form and persist into a quasi steady state. These results may be relevant to the L-H transition, the early stages of the pedestal and edge transport barrier formation.

  9. Two-dimensional magnetohydrodynamic simulations of poloidal flows in tokamaks and MHD pedestal

    SciTech Connect

    Guazzotto, L.; Betti, R.

    2011-09-15

    Poloidal rotation is routinely observed in present-day tokamak experiments, in particular near the plasma edge and in the high-confinement mode of operation. According to the magnetohydrodynamic (MHD) equilibrium theory [R. Betti and J. P. Freidberg, Phys. Plasmas 7, 2439 (2000)], radial discontinuities form when the poloidal velocity exceeds the poloidal sound speed (or rather, more correctly, the poloidal magneto-slow speed). Two-dimensional compressible magnetohydrodynamic simulations show that the transonic discontinuities develop on a time scale of a plasma poloidal revolution to form an edge density pedestal and a localized velocity shear layer at the pedestal location. While such an MHD pedestal surrounds the entire core, the outboard side of the pedestal is driven by the transonic discontinuity while the inboard side is caused by a poloidal redistribution of the mass. The MHD simulations use a smooth momentum source to drive the poloidal flow. Soon after the flow exceeds the poloidal sound speed, the density pedestal and the velocity shear layer form and persist into a quasi steady state. These results may be relevant to the L-H transition, the early stages of the pedestal and edge transport barrier formation.

  10. Near Field Antenna Measurement System.

    DTIC Science & Technology

    1982-03-01

    beam pointing accuracy and .6 dB gain accuracy. These antennas are both planar arrays with the X-band antenna scanning with ferrite phase shifters in...AD-A114 125 M[ES AIRCRAFT CO FULLERTON CA F/ 17/9 NEAR FIELD ANTENNA MEASUREMENT SYSTEM. (U) MAR 82 A E HOLLEY DAABO7-7?-C-1 87 UNCLASSIFIED NL...IllIHE El. onhEnoh IIIIhh --h h I~m I I Research and Development Technical Report I DAABO7-77-C-0587-F1 NEAR FIELD ANTENNA I MEASUREMENT SYSTEM I A.E

  11. Effects of beam-driven poloidal rotation on the neoclassical bootstrap current

    SciTech Connect

    Lin-Liu, Y.R.; Hinton, F.L.

    1996-12-31

    Unbalanced neutral beam injection drives toroidal and poloidal rotations in a tokamak plasma. The beam toroidal momentum input drives the toroidal rotation, and the parallel friction between the thermal ions and fast ions induces the poloidal rotation. A theory of the beam-driven poloidal rotation and its effects on energy transport was given recently by Hinton and Kim. In this work, we extend their considerations to the effects on the neoclassical bootstrap current. For parameters of interest in present neutral beam heated tokamaks, the magnitude of the beam-driven poloidal rotation can be significantly larger than that of the standard neoclassical value due to the ion temperature gradient. The presence of this driven poloidal rotation will manifest itself in modification of the neoclassical bootstrap current. In the case of coinjection, the driven poloidal rotation is in the opposite direction to the rotation driven by the temperature gradient, therefore it enhances the bootstrap current. In comparison with the standard theoretical predictions of the neutral beam-driven current, that enhancement in the bootstrap current varies with the beam and plasma parameters. A calculation of the parallel transport coefficients associated with the driven poloidal flow in finite-aspect ratio tokamaks will be presented. Experimental conditions for observing the enhancement in bootstrap current will be discussed.

  12. Poloidal flux linkage requirements for the International Thermonuclear Experimental Reactor

    SciTech Connect

    Jardin, S.C.; Kessel, C.; Pomphrey, N.

    1994-01-01

    We have applied two computational models to calculate the poloidal flux linkage requirements for the current ramp-up and for the flattop phase of the proposed International Thermonuclear Experimental Reactor (ITER). For the current ramp-up phase, we have used the TSC code to simulate the entire current ramp-up period as described in the TAC-3 Physics Report. We have extended the time of the simulation to cover the full current penetration time, that is, until the loop voltage is a constant throughout the plasma. Sensitivity studies have been performed with respect to current ramp-up time, impurity concentration, and to the time of onset of auxiliary heating. We have also used a steady state plasma equilibrium code that has the constant loop voltage constraint built in to survey the dependence of the steady state loop-voltage on the density and temperature profiles. This calculation takes into account the plasma bootstrap current contribution, including non-circular and collisional corrections. The results can be displayed as contours of the loop-voltage on a POPCON like diagram.

  13. Poloidal variation of high-Z impurity density in Alcator C-Mod ICRF-heated plasmas

    NASA Astrophysics Data System (ADS)

    Reinke, Matthew

    2012-10-01

    The poloidal variation of molybdenum density is measured in the core of ICRF-heated Alcator C-Mod plasmas and found to exhibit strong in/out asymmetries. Existing neoclassical parallel impurity transport theory is extended to include the effects of fast-ions and is shown to agree quantitatively with C-Mod measurements. The flux-surface variation of molybdenum is well described by nz(θ)/=1+nz,c cos(θ)+nz,ssin(θ), where -0.2 < nz,c/ < 0.3 and -0.1 < nz,s/ < 0.1 are observed over a wide range of Ohmic, L/I-mode and EDA H-mode plasmas for r/a < 0.9. The in/out asymmetry, nz,c/, is determined by a combination of centrifugal force due to toroidal rotation, leading to low-field side (LFS) accumulation, and poloidal electric fields sustained by magnetic trapping of cyclotron heated minority ions, leading to high field side (HFS) accumulation. While LFS accumulation due to centrifugal effects has been seen on other tokamaks, this represents the first observation of the effect driven entirely by intrinsic rotation. Scans of the D(H) resonance layer are shown to modify the in/out asymmetry by altering the fast-ion temperature anisotropy, T-/T||, and changing the ICRF power density, PRF/ne, either by ramping down the input power or increasing the density is found to reduce HFS accumulation. Observations of up/down asymmetries nz,s/, of molybdenum density are found to disagree with existing theories in the trace limit, nzZ^2/ni 1, in the collisionless main-ion regime. The link between nz(θ) and poloidal rotation, vθ, is emphasized, as both are assumed to be determined by neoclassical parallel impurity transport, and a more rigorous test of theory which includes matching asymmetries and vθ is discussed. The use of the poloidal variation in nz as a diagnostic for Eθ and T-/T|| as well as the impact of nz,c/ on radial transport are also discussed.

  14. The role of parallel and poloidal heat flux in setting the detachment threshold in DIII-D

    NASA Astrophysics Data System (ADS)

    Hill, D. N.; Allen, S. L.; Lasnier, C. J.; McLean, A. G.; Petrie, T. W.; Leonard, A. W.; Groth, M.

    2014-10-01

    Experimental results show that the threshold density for divertor detachment is reduced even as the parallel scrape-off-layer (SOL) heat flux (q| |) is more than doubled, contrary to expectation. The work is part of a systematic study to identify the physics basis for obtaining detached divertors in future high power burning plasma experiments, consistent with requirements for high confinement steady-state operation. Parallel heat flux [PSOL * (Btor /Bpol) / 2 πRλq ; λq is the SOL width] is independent of poloidal flux expansion and is commonly used to quantify the divertor heat flux challenge. In these experiments, the parallel heat flux was varied either by changing the heating power (thereby PSOL), plasma current (the SOL width), or toroidal field (the projection of PSOL onto Btor). The data point to poloidal-field physics effects (e.g., neutral penetration field, line length, and impurity radiation volume) playing a dominant role in setting the detachment threshold. Comparison with 2D simulation will be shown. Work supported by the US DOE under DE-AC52-07NA27344 and DE-FC02-04ER54698.

  15. TPX: Contractor preliminary design review. Volume 2, PF systems engineering

    SciTech Connect

    Calvin, H.A.

    1995-07-28

    This system development specification covers the Poloidal Field (PF) Magnet System, WBS 14 in the Princeton Plasma Physics Laboratory TPX Program to build a tokamak fusion reactor. This specification establishes the performance, design, development and test requirements of the PF Magnet System.

  16. Multipoint spacecraft observations of long-lasting poloidal Pc4 pulsations in the dayside magnetosphere on 1-2 May 2014

    NASA Astrophysics Data System (ADS)

    Korotova, Galina; Sibeck, David; Engebretson, Mark; Wygant, John; Thaller, Scott; Spence, Harlan; Kletzing, Craig; Angelopoulos, Vassilis; Redmon, Robert

    2016-11-01

    We use magnetic field and plasma observations from the Van Allen Probes, Time History of Events and Macroscale Interactions during Substorms (THEMIS) and Geostationary Operational Environmental Satellite system (GOES) spacecraft to study the spatial and temporal characteristics of long-lasting poloidal Pc4 pulsations in the dayside magnetosphere. The pulsations were observed after the main phase of a moderate storm during low geomagnetic activity. The pulsations occurred during various interplanetary conditions and the solar wind parameters do not seem to control the occurrence of the pulsations. The most striking feature of the Pc4 magnetic field pulsations was their occurrence at similar locations during three of four successive orbits. We used this information to study the latitudinal nodal structure of the pulsations and demonstrated that the latitudinal extent of the magnetic field pulsations did not exceed 2 Earth radii (RE). A phase shift between the azimuthal and radial components of the electric and magnetic fields was observed from ZSM = 0.30 RE to ZSM = -0.16 RE. We used magnetic and electric field data from Van Allen Probes to determine the structure of ULF waves. We showed that the Pc4 magnetic field pulsations were radially polarized and are the second-mode harmonic waves. We suggest that the spacecraft were near a magnetic field null during the second orbit when they failed to observe the magnetic field pulsations at the local times where pulsations were observed on previous and successive orbits. We investigated the spectral structure of the Pc4 pulsations. Each spacecraft observed a decrease of the dominant period as it moved to a smaller L shell (stronger magnetic field strength). We demonstrated that higher frequencies occurred at times and locations where Alfvén velocities were greater, i.e., on Orbit 1. There is some evidence that the periods of the pulsations increased during the plasmasphere refilling following the storm.

  17. Optical Potential Field Mapping System

    NASA Technical Reports Server (NTRS)

    Reid, Max B. (Inventor)

    1996-01-01

    The present invention relates to an optical system for creating a potential field map of a bounded two dimensional region containing a goal location and an arbitrary number of obstacles. The potential field mapping system has an imaging device and a processor. Two image writing modes are used by the imaging device, electron deposition and electron depletion. Patterns written in electron deposition mode appear black and expand. Patterns written in electron depletion mode are sharp and appear white. The generated image represents a robot's workspace. The imaging device under processor control then writes a goal location in the work-space using the electron deposition mode. The black image of the goal expands in the workspace. The processor stores the generated images, and uses them to generate a feedback pattern. The feedback pattern is written in the workspace by the imaging device in the electron deposition mode to enhance the expansion of the original goal pattern. After the feedback pattern is written, an obstacle pattern is written by the imaging device in the electron depletion mode to represent the obstacles in the robot's workspace. The processor compares a stored image to a previously stored image to determine a change therebetween. When no change occurs, the processor averages the stored images to produce the potential field map.

  18. Two-dimensional MHD simulations of tokamak plasmas with poloidal flow

    NASA Astrophysics Data System (ADS)

    Hu, Bo; Betti, R.

    2006-10-01

    It has been shown [1] that, according to the ideal MHD equilibrium theory, poloidal flow in a tokamak can give rise to a pedestal structure with the pressure, density and velocity developing sharp discontinuities in their radial profiles. Such a pedestal arises when the poloidal velocity exceeds the poloidal sound speed. Since the poloidal sound speed vanishes at the separatrix, it is conceivable that evena rather slow poloidal flow can become transonic near the plasma edge, thus inducing a pedestal in the hydrodynamic profiles. While equilibrium calculations [1-4] of such a pedestal are well established, only a few two-dimensional time-dependent simulations have been carried out [5]. Here, we show the preliminary results from a two dimensional MHD code that simulates the formation of the pedestal starting from a poloidal velocity profile that becomes supersonic at the plasma edge. This work was supported by US-DOE under Contract DE-FG02-93ER54215. [1] Betti and Freidberg, Phys. Plasmas 7, 2439 (2000). [2] Guazzotto, Betti, Manickam and Kaye, Phys. Plasmas 11, 604 (2004). [3] Guazzotto and Betti, Phys. Plasmas 12, 056107 (2005). [4] Thyagaraja and McClements, Phys. Plasmas 13, 062502 (2006). [5] Gardiner, Betti and Guazzotto, Bull. Am. Phys. Soc. 46, No. 8, 166 (2001).

  19. Fast damping of poloidal Alfven waves by bounce-resonant ions: observations and modeling

    NASA Astrophysics Data System (ADS)

    Wang, C.; Rankin, R.; Sydorenko, D.; Zong, Q.

    2015-12-01

    Interplanetary shocks and solar wind dynamic pressure variations can excite intense ultra-low-frequency (ULF) waves in the inner magnetosphere. An analysis of two interplanetary shocks observed by Cluster on 7 November 2004 and 30 August 2001 shows that the poloidal waves excited in these events are damped away rapidly in tens of minutes. This damping is the result of wave-particle interactions involving H+ and O+ ions with energies in the range of several to a few tens of keV [Wang et al., J. Geophys. Res., 2015]. Damping is found to be more effective in the plasmasphere boundary layer due to the relatively higher proportion of Landau resonant ions that exists in that region. In the November 2004 shock event it has been suggested that energy-dispersed ions observed travelling parallel and anti-parallel direction to the geomagnetic field immediately after the shockare locally accelerated rather than originating from Earth's ionosphere. We use test-particle simulations to show that adiabatic advection of the particle differential flux caused bydrift-bounce-resonance with ULF waves is responsible for the energy-dispersed ions observed in these events. In the simulations,Liouville's theorem is used to reconstruct the iondistribution function and differential flux in a model dipole magnetosphere.It is shown that flux modulations of H and O ions can be reproduced when test-particle ions are advanced in the electric fields of the 3D ULF wave model we have developed.

  20. The superconducting magnet system for the Tokamak Physics Experiment

    SciTech Connect

    Lang, D.D.; Bulmer, R.J.; Chaplin, M.R.

    1994-06-18

    The superconducting magnet system for the Tokamak Physics experiment (TPX) will be the first all superconducting magnet system for a Tokamak, where the poloidal field coils, in addition to the toroidal field coils are superconducting. The magnet system is designed to operate in a steady state mode, and to initiate the plasma discharge ohmically. The toroidal field system provides a peak field of 4.0 Tesla on the plasma axis at a plasma major radius of 2.25 m. The peak field on the niobium 3-tin, cable-in-conduit (CIC) conductor is 8.4 Tesla for the 16 toroidal field coils. The toroidal field coils must absorb approximately 5 kW due to nuclear heating, eddy currents, and other sources. The poloidal field system provides a total of 18 volt seconds to initiate the plasma and drive a plasma current up to 2 MA. The poloidal field system consists of 14 individual coils which are arranged symmetrically above and below the horizontal mid plane. Four pairs of coils make up the central solenoid, and three paris of poloidal ring coils complete the system. The poloidal field coils all use a cable-in-conduit conductor, using either niobium 3-tin (NB{sub 3}Sn) or niobium titanium (NbTi) superconducting strands depending on the operating conditions for that coil. All of the coils are cooled by flowing supercritical helium, with inlet and outlet connections made on each double pancake. The superconducting magnet system has gone through a conceptual design review, and is in preliminary design started by the LLNL/MIT/PPPL collaboration. A number of changes have been made in the design since the conceptual design review, and are described in this paper.

  1. Canonical straight field line magnetic flux coordinates for tokamaks

    NASA Astrophysics Data System (ADS)

    Li, Meng; Breizman, Boris N.; Zheng, Linjin

    2016-12-01

    New global straight field line coordinates are introduced for a toroidal plasma configuration. The new coordinate system provides a canonical description of particle guiding center motion while maintaining the straight field line feature. These coordinates are convenient for combining MHD calculations with kinetic modeling of energetic particles. We demonstrate how the new coordinate system can be constructed by transforming the poloidal and toroidal angles. Numerical examples show comparison of the new coordinates with various non-canonical coordinates for the same equilibrium configuration.

  2. Development of real-time rotating waveplate Stokes polarimeter using multi-order retardation for ITER poloidal polarimeter

    SciTech Connect

    Imazawa, R. Kawano, Y.; Ono, T.; Itami, K.

    2016-01-15

    The rotating waveplate Stokes polarimeter was developed for ITER (International Thermonuclear Experimental Reactor) poloidal polarimeter. The generalized model of the rotating waveplate Stokes polarimeter and the algorithm suitable for real-time field-programmable gate array (FPGA) processing were proposed. Since the generalized model takes into account each component associated with the rotation of the waveplate, the Stokes parameters can be accurately measured even in unideal condition such as non-uniformity of the waveplate retardation. Experiments using a He-Ne laser showed that the maximum error and the precision of the Stokes parameter were 3.5% and 1.2%, respectively. The rotation speed of waveplate was 20 000 rpm and time resolution of measuring the Stokes parameter was 3.3 ms. Software emulation showed that the real-time measurement of the Stokes parameter with time resolution of less than 10 ms is possible by using several FPGA boards. Evaluation of measurement capability using a far-infrared laser which ITER poloidal polarimeter will use concluded that measurement error will be reduced by a factor of nine.

  3. Development of real-time rotating waveplate Stokes polarimeter using multi-order retardation for ITER poloidal polarimeter

    NASA Astrophysics Data System (ADS)

    Imazawa, R.; Kawano, Y.; Ono, T.; Itami, K.

    2016-01-01

    The rotating waveplate Stokes polarimeter was developed for ITER (International Thermonuclear Experimental Reactor) poloidal polarimeter. The generalized model of the rotating waveplate Stokes polarimeter and the algorithm suitable for real-time field-programmable gate array (FPGA) processing were proposed. Since the generalized model takes into account each component associated with the rotation of the waveplate, the Stokes parameters can be accurately measured even in unideal condition such as non-uniformity of the waveplate retardation. Experiments using a He-Ne laser showed that the maximum error and the precision of the Stokes parameter were 3.5% and 1.2%, respectively. The rotation speed of waveplate was 20 000 rpm and time resolution of measuring the Stokes parameter was 3.3 ms. Software emulation showed that the real-time measurement of the Stokes parameter with time resolution of less than 10 ms is possible by using several FPGA boards. Evaluation of measurement capability using a far-infrared laser which ITER poloidal polarimeter will use concluded that measurement error will be reduced by a factor of nine.

  4. Linear and non-linear numerical simulations of poloidal Alfven waves

    NASA Astrophysics Data System (ADS)

    Ribeiro, A.

    2013-05-01

    Among the many of numerical simulations of MHD turbulence, few studies had been made of Alfven waves interacting with realistic boundaries. Thus, we have developed a novel hybrid spectral/finite element code, which is capable of simulate properly realistic boundaries properties. Our model is based on a Fourier decompositions of all variables in the azimuthal direction and on a finite element projection in the meridian plan. In order to simulate realistic boundary conditions for the magnetic field we solve the induction equation enforcing continuity of the magnetic field H at the interface with the external insulating medium through a Interior Penalty Galerkin method (IPG) [1]. I will present the results of our investigation of Alfven waves propagating in a cylinder filled of liquid metal submitted to an axial magnetic field. Poloidal Alfven waves are excited magnetically by imposing an azimuthal current pulse at the bottom of the cylinder. In the linear axisymmetric model we find a good agreement with previous experiments in liquid metals by Lundquist and by Lenhert and more recently by Alboussiere et al [2]. This axisymmetric study is extended to the non linear regime, where the amplitudes of the perturbations are comparable to the external applied magnetic field,in this conditions a complex response is found due to waves waves interactions. [1] J. L. Guermond, J.L Leorat, F. Luddens, C. Nore, A. Ribeiro. Effects of discontinuous magnetic permeability on magnetodynamic problems, Journal of Computational Physics Volume 230, Issue 16, 10 July 2011, Pages 6299 -- 6319. [2] T. Alboussiere, P. Cardin, F. Debray, H. C. Nataf, F. Plunian, A. Ribeiro, D. Schmitt, Experimental evidence of Alfven wave propagation in a Gallium alloy, Physics of fluids, 2011, vol. 23, nb 9.

  5. Influence of the poloidal equilibrium flow and flow shear on the tearing mode instabilities in tokamak plasmas

    NASA Astrophysics Data System (ADS)

    Ming, Yue; Zhou, Deng

    2017-01-01

    The effect of the poloidal equilibrium flow and flow shear on the tearing mode instabilities for tokamak plasmas is investigated. The vorticity equation is derived and approximately solved for large poloidal mode numbers (m). Asymptotic matching of the inner solution to the outer solution can approximately give the classical tearing mode stability index Δ' . For typical plasma parameters with positive flow shear, we notice that the poloidal mean flows have a beneficial effect on the classical tearing mode and vice versa. To study the modes with arbitrary poloidal mode numbers, we numerically solve the vorticity equation for delta prime ( Δ' ) for typical plasma parameters with positive flow shear at the rational surface and the resulting Δ' with large m also decreases with increasing poloidal flow velocity, consistent with the approximate analytical large m results. Our numerical calculations indicate that the poloidal mean flow with positive flow shear has beneficial influence on the stabilization of classical tearing modes in tokamak plasmas.

  6. What is control of turbulence in crossed fields?

    NASA Astrophysics Data System (ADS)

    Volchenkov, Dimitri

    2010-02-01

    Convective instability in the cross-field system of thermonuclear reactors can be overridden by poloidal drifts. While in crossed fields, a long-time, large-scale turbulent regime, in which the eddies of some particular size are destined to persist longer than usual, would come into being. Perhaps, we may keep such vortexes using them as tools for maintaining the stability of still an illusory construct of plasma fusion.

  7. Magnetic-field-dosimetry system

    DOEpatents

    Lemon, D.K.; Skorpik, J.R.; Eick, J.L.

    1981-01-21

    A device is provided for measuring the magnetic field dose and peak field exposure. The device includes three Hall-effect sensors all perpendicular to each other, sensing the three dimensional magnetic field and associated electronics for data storage, calculating, retrieving and display.

  8. E × B flow velocity deduced from the poloidal motion of fluctuation patterns in neutral beam injected L-mode plasmas on KSTAR

    NASA Astrophysics Data System (ADS)

    Lee, W.; Leem, J.; Yun, G. S.; Park, H. K.; Ko, S. H.; Choi, M. J.; Wang, W. X.; Budny, R. V.; Ethier, S.; Park, Y. S.; Luhmann, N. C.; Domier, C. W.; Lee, K. D.; Ko, W. H.; Kim, K. W.

    2016-05-01

    A method for direct assessment of the equilibrium E × B flow velocity ( E ×B flow shear is responsible for the turbulence suppression and transport reduction in tokamak plasmas) is investigated based on two facts. The first one is that the apparent poloidal rotation speed of density fluctuation patterns is close to the turbulence rotation speed in the direction perpendicular to the local magnetic field line within the flux surface. And the second "well-known" fact is that the turbulence rotation velocity consists of the equilibrium E × B flow velocity and intrinsic phase velocity of turbulence in the E × B flow frame. In the core region of the low confinement (L-mode) discharges where a strong toroidal rotation is induced by neutral beam injection, the apparent poloidal velocities (and turbulence rotation velocities) are good approximations of the E ×B flow velocities since linear gyrokinetic simulations suggest that the intrinsic phase velocity of the dominant turbulence is significantly lower than the apparent poloidal velocity. In the neutral beam injected L-mode plasmas, temporal and spatial scales of the measured turbulence are studied by comparing with the local equilibrium parameters relevant to the ion-scale turbulence.

  9. Equilibrium field coil concepts for INTOR

    SciTech Connect

    Strickler, D.J.; Peng, Y.K.M.; Brown, T.G.

    1981-08-01

    Methods are presented for reducing ampere-turn requirements in the EF coil system. It is shown that coil currents in an EF coil system external to the toroidal field coils can be substantially reduced by relaxing the triangularity of a D-shaped plasma. Further reductions are realized through a hybrid EF coil system using both internal and external coils. Equilibrium field coils for a poloidally asymmetric, single-null INTOR configuration are presented. It is shown that the shape of field lines in the plasma scrapeoff region and divertor channel improves as triangularity is reduced, but it does so at the possible expense of achievable stable beta values.

  10. Long-Term Monitoring of Hydraulic Characteristics of LHD Poloidal Coils

    NASA Astrophysics Data System (ADS)

    Takahata, Kazuya; Moriuchi, Sadatomo; Ooba, Kouki; Mito, Toshiyuki; Imagawa, Shinsaku

    We present a fourteen-year data summary of the hydraulic characteristics of the large helical device (LHD) poloidal coils. The superconductors of the poloidal coils are cable-in-conduit conductors (CICC) cooled by circulated supercritical helium. The long-term operation of the LHD demonstrates that the initial hydraulic characteristics can be maintained without flow obstruction. Fine mesh filters installed at the inlet trapped impurities during cool-down of the coils, confirmed by monitoring the pressure drop of the filters. The filters have an important role in removing particles of impurities in the helium and maintaining the hydraulic characteristics of the coils.

  11. Poloidal flow and toroidal particle ring formation in a sessile drop driven by megahertz order vibration.

    PubMed

    Rezk, Amgad R; Yeo, Leslie Y; Friend, James R

    2014-09-23

    Poloidal flow is curiously formed in a microliter sessile water drop over 157-225 MHz because of acoustic streaming from three-dimensional standing Lamb waves in a lithium niobate substrate. The flow possesses radial symmetry with downwelling at the center and upwelling around the periphery of the drop. Outside this frequency range, the attenuation occurs over a length scale incompatible with the drop size and the poloidal flow vanishes. Remarkably, shear-induced migration was found to drive toroidal particle ring formation with diameters inversely proportional to the frequency of the acoustic irradiation.

  12. New Manning System Field Evaluation

    DTIC Science & Technology

    1986-03-01

    our Analytic hodel (see Chapter 5, New Manning Svestem Field Evaluacion . Technical Revore No. I, RAJL-, November c t, e number or soldiers retaking...and meaningful performance measures are not only crucial to the WRAIR N Field Evaluacion but also to the Army. To know which unit does betzer than

  13. Anomalous toroidal field penetration in Tormac V

    SciTech Connect

    Feinberg, B.; Vaucher, B. G.; Shaw, R. S.; Vella, M. C.

    1981-07-01

    We investigate magnetic field penetration into a cool, collisional, magnetized plasma in Tormac V. Magnetic probe and laser interferometer studies reveal anomalous penetration of the applied toroidal field into a plasma with an initial parallel bias toroidal field. The applied poloidal field, however, formed a well-defined magnetic front which was effective at sweeping up particles. Lastly, strong shear in the vacuum magnetic field does not inhibit the apparent decoupling of the applied toroidal field from the applied poloidal field.

  14. Initiation of bipolar flows by magnetic field twisting in protostellar nebulae

    NASA Technical Reports Server (NTRS)

    Newman, William I.; Newman, Alice L.; Lovelace, Richard V. E.

    1992-01-01

    A model is developed for the time-dependent twisting of an initial poloidal magnetic field threading a conducting protostellar disk. The region outside the disk is assumed to be filled, at least initially, with a low-density, force-free 'coronal' plasma. The differential rotation of the disk acts to twist the B field in the space outside the disk thus generating a toroidal magnetic field. In turn, the toroidal field acts to pinch the plasma and the poloidal field toward the system axis producing a collimated channel. This channel could facilitate the formation of bipolar flows. The magnitude and duration of the field twisting is expected to be limited by magnetohydrodynamic instability.

  15. Testing neoclassical and turbulent effects on poloidal rotation in the core of DIII-D

    SciTech Connect

    Chrystal, C.; Burrell, K. H.; Staebler, G. M.; Kinsey, J. E.; Lao, L. L.; Grassie, J. S. de; Grierson, B. A.; Solomon, W. M.; Wang, W. X.; Rhodes, T. L.; Schmitz, L.; Mordijck, S.; Meneghini, O.

    2014-07-15

    Experimental tests of ion poloidal rotation theories have been performed on DIII-D using a novel impurity poloidal rotation diagnostic. These tests show significant disagreements with theoretical predictions in various conditions, including L-mode plasmas with internal transport barriers (ITB), H-mode plasmas, and QH-mode plasmas. The theories tested include standard neoclassical theory, turbulence driven Reynolds stress, and fast-ion friction on the thermal ions. Poloidal rotation is observed to spin up at the formation of an ITB and makes a significant contribution to the measurement of the E{sup →}×B{sup →} shear that forms the ITB. In ITB cases, neoclassical theory agrees quantitatively with the experimental measurements only in the steep gradient region. Significant quantitative disagreement with neoclassical predictions is seen in the cores of ITB, QH-, and H-mode plasmas, demonstrating that neoclassical theory is an incomplete description of poloidal rotation. The addition of turbulence driven Reynolds stress does not remedy this disagreement; linear stability calculations and Doppler backscattering measurements show that disagreement increases as turbulence levels decline. Furthermore, the effect of fast-ion friction, by itself, does not lead to improved agreement; in QH-mode plasmas, neoclassical predictions are closest to experimental results in plasmas with the largest fast ion friction. Predictions from a new model that combines all three effects show somewhat better agreement in the H-mode case, but discrepancies well outside the experimental error bars remain.

  16. Poloidal flow driven by ion-temperature-gradient turbulence in tokamaks

    SciTech Connect

    Rosenbluth, M.N.; Hinton, F.L.

    1998-01-01

    We show that linear collisionless processes do not damp poloidal flows driven by ion-temperature-gradient (ITG) turbulence. Since these flows play an important role in saturating the level of the turbulence, this level, as well as the transport caused by ITG modes, may be overestimated by gyrofluid simulations, which employ linear collisionless rotation damping. {copyright} {ital 1998} {ital The American Physical Society}

  17. Poloidal tilting symmetry of high order tokamak flux surface shaping in gyrokinetics

    NASA Astrophysics Data System (ADS)

    Ball, Justin; Parra, Felix I.; Barnes, Michael

    2016-04-01

    A poloidal tilting symmetry of the local nonlinear δ f gyrokinetic model is demonstrated analytically and verified numerically. This symmetry shows that poloidally rotating all the flux surface shaping effects with large poloidal mode number by a single tilt angle has an exponentially small effect on the transport properties of a tokamak. This is shown using a generalization of the Miller local equilibrium model to specify an arbitrary flux surface geometry. With this geometry specification we find that, when performing an expansion in large flux surface shaping mode number, the governing equations of gyrokinetics are symmetric in the poloidal tilt of the high order shaping effects. This allows us to take the fluxes from a single configuration and calculate the fluxes in any configuration that can be produced by tilting the large mode number shaping effects. This creates a distinction between tokamaks with mirror symmetric flux surfaces and tokamaks without mirror symmetry, which is expected to have important consequences for generating toroidal rotation using up-down asymmetry.

  18. Electro-Optic Surface Field Imaging System

    DTIC Science & Technology

    1989-06-01

    ELECTRO - OPTIC SURFACE FIELD IMAGING SYSTEM L. E. Kingsley and W. R. Donaldson LABORATORY FOR LASER ENERGETICS University of Rochester 250 East...surface electric fields present during switch operation. The electro - optic , or Pockel’s effect, provides an extremely useful probe of surface electric...fields. Using the electro - optic effect, surface fields can be measured with an optical probe. This paper describes an electro - optic probe which is

  19. Unit Manning System Field Evaluation

    DTIC Science & Technology

    1986-12-15

    set ot’ discrete events or manipulwtions of events will create vertical cohesion in an organizacional climate where Leaders behave unpredictably and... Civil War, all were Individual replacement systems. However, each faoregn system wax able to provide all echelons of unit replacement as well. There...from survivors of veteran combat units or adding "green" roplacesents to a unit--are not new. In the united States as far back as the Civil War

  20. Collisionality Scaling of Main-ion Toroidal and Poloidal Rotation in Low Torque DIII-D Plasmas

    SciTech Connect

    B A Grierson, et al

    2013-05-10

    In tokamak plasmas with low levels of toroidal rotation, the radial electric fi eld Er is a combination of pressure gradient and toroidal and poloidal rotation components, all having similar magnitudes. In order to assess the validity of neoclassical poloidal rotation theory for determining the poloidal rotation contribution to Er , Dα emission from neutral beam heated tokamak discharges in DIII-D [J.L. Luxon, Nucl. Fusion 42 , 614 (2002)] has been evaluated in a sequence of low torque (electron cyclotron resonance heating and balanced diagnostic neutral beam pulse) discharges to determine the local deuterium toroidal rotation velocity. By invoking the radial force balance relation the deuterium poloidal rotation can be inferred. It is found that the deuterium poloidal low exceeds the neoclassical value in plasmas with collisionality νi < 0: 1, being more ion diamagnetic, and with a stronger dependence on collisionality than neoclassical theory predicts. At low toroidal rotation, the poloidal rotation contribution to the radial electric fi eld and its shear is signi cant. The eff ect of anomalous levels of poloidal rotation on the radial electric fi eld and cross fi eld heat transport is investigated for ITER parameters.

  1. A study of poloidal asymmetries in the pedestal region

    NASA Astrophysics Data System (ADS)

    Churchill, R. M.; Lipschultz, B.; Lisgo, S.; Reimold, F.; Goldstein, J.; Alcator C-Mod Team Team

    2011-10-01

    Simultaneous CXRS measurements of boron density, velocity, and temperature in the pedestal region (0 . 8 < r / a < 1 . 05) at the low- and high-field sides (LFS and HFS) of Alcator C-Mod allow studies of variations in boron density and total velocity on a flux surface. While previous studies used different neutral sources (a 50keV hydrogen neutral beam at the LFS and a thermal D2 gas puff at the HFS) to localize CXRS measurements we have recently expanded our diagnostic set to allow thermal gas CXRS at both locations, thus removing uncertainties due to different measurement techniques and cross-section. We have also upgraded our modelling capability to utilize the DIVIMP code, which uses the plasma-neutral code combination of OSM-EIRENE to determine the local neutral density. Comparisons between CXRS methods using different neutral sources will be shown as well as an exploration of whether the constants K(ψ) and ω(ψ) in the description of V =K/(ψ) n B + ω (ψ)R2 ∇ ϕ are constant on a flux surface as typically assumed. The above comparisons will be shown for a variety of H-mode and I-mode plasmas. Supported by USDoE award DE-FC02-99ER54512.

  2. Spheromak aspect-ratio effects on poloidal flux amplification

    NASA Astrophysics Data System (ADS)

    Hooper, E. B.; McLean, H. S.; Romero-Talamas, C. A.; Wood, R. D.

    2008-11-01

    A short experimental run at the end of SSPX operation examined the effect of increasing the flux conserver length-to-aspect ration, L/R, from 1 to 1.2, thereby reducing the formation threshold for λgun=μ0Igun/ψgun from 10 m-1 to 7.5 m-1 with a corresponding increase in power efficiency [1]. Resistive MHD (NIMROD) simulations of flux amplification which agreed well with experiment at L/R=1 [2] agree fairly well with L/R=1.2 and have been extended to L/R=1.6, just under the tilt-mode stability limit (1.67) for an isolated spheromak. At the longest length, helicity injection changes from a chaotic relaxation process to a steady, high amplitude n=1 mode which opens the field lines throughout most of the flux conserver. Calculations are presented to elucidate the characteristics of the chaos for the standard flux-conserver dimensions. Comparisons are made among the simulations to determine the ``optimum'' L/R based on a trade-off between spheromak buildup efficiency and low mode activity. [1] R. D. Wood, et al., submitted to Phys. Rev. Letters. [2] E. B. Hooper, et al., Nucl. Fusion 47, 1064 (2007).

  3. Dynamics of axisymmetric E x B and poloidal flows in tokamaks

    SciTech Connect

    Hinton, F.L.; Rosenbluth, M.N.

    1998-07-01

    As a result of turbulence and finite Larmor radius effects, random radial currents are present in a tokamak plasma, and these drive sheared axisymmetric poloidal flows. The authors model these currents with a noise source with given statistical properties and calculate the linear kinetic response to this source. Without collisions, there is no long term damping of these flows; when collisions are included, poloidal flows are damped. The mean square potential associated with these flows is given in terms of the linear response function they calculate and a model correlation function for the current source. Without collisions, the mean square E {times} B flow increases linearly with time, but with collisions, it reaches a steady state. In the long correlation time limit, the collisionless residual flows are important in determining the mean square E {times} B flow.

  4. Poloidal radiation asymmetries during disruption mitigation by massive gas injection on the DIII-D tokamak

    NASA Astrophysics Data System (ADS)

    Eidietis, N. W.

    2016-10-01

    Measurements of poloidal asymmetry in the radiated power during thermal quench (TQ) mitigation by massive gas injection (MGI) on DIII-D show poloidal peaking in the radiated heat flux at the wall generally consistent with 3D resistive MHD modeling, that indicates a large n=1 tearing mode causes these asymmetries. Radiation asymmetries are a concern to ITER because they can cause localized melting of the first wall even if globally the mitigation successfully radiates 100% of the plasma thermal energy. Toroidal radiation asymmetries have been well-studied, but until now the equally important poloidal asymmetries were not well constrained. Radiation emissivity profiles are reconstructed by tomographic inversion of AXUV photodiode arrays, from which the peaking measurements are derived. The poloidal peaking measurements are compared to NIMROD 3D resistive MHD simulations. Qualitatively, the measured and modeled peaking evolve similarly. In both cases, peaking during the TQ changes little with toroidal phase, consistent with predictions of n=1 MHD during the TQ producing the asymmetry. Quantitatively, the measured TQ peaking amplitudes are comparable to but consistently higher than the modeled values. This is a result of the measured radiation exhibiting high emissivity lobes at larger minor radius (and outside the separatrix) than the modeled cases, which may indicate incomplete treatment of the plasma-neutral interaction at the plasma edge in the model. This work, combined with previous measurement and modeling and toroidal radiation asymmetries, provides a basis for constraining localized mitigation radiation heat flux in ITER. Work supported by US DOE under DE-FC02-04ER54698.

  5. Stereoscopic wide field of view imaging system

    NASA Technical Reports Server (NTRS)

    Prechtl, Eric F. (Inventor); Sedwick, Raymond J. (Inventor); Jonas, Eric M. (Inventor)

    2011-01-01

    A stereoscopic imaging system incorporates a plurality of imaging devices or cameras to generate a high resolution, wide field of view image database from which images can be combined in real time to provide wide field of view or panoramic or omni-directional still or video images.

  6. Field Mapping System for Solenoid Magnet

    NASA Astrophysics Data System (ADS)

    Park, K. H.; Jung, Y. K.; Kim, D. E.; Lee, H. G.; Park, S. J.; Chung, C. W.; Kang, B. K.

    2007-01-01

    A three-dimensional Hall probe mapping system for measuring the solenoid magnet of PLS photo-cathode RF e-gun has been developed. It can map the solenoid field either in Cartesian or in cylindrical coordinate system with a measurement reproducibility better than 5 × 10-5 T. The system has three axis motors: one for the azimuthal direction and the other two for the x and z direction. This architecture makes the measuring system simple in fabrication. The magnetic center was calculated using the measured axial component of magnetic field Bz in Cartesian coordinate system because the accuracy of magnetic axis measurement could be improved significantly by using Bz, instead of the radial component of magnetic field Br. This paper describes the measurement system and summarizes the measurement results for the solenoid magnetic of PLS photo-cathode RF e-gun.

  7. Reliability of photovoltaic systems: A field report

    NASA Astrophysics Data System (ADS)

    Thomas, M. G.; Fuentes, M. K.; Lashway, C.; Black, B. D.

    Performance studies and field measurements of photovoltaic systems indicate a 1 to 2% per year degradation in array energy production. The cause for much of the degradation has been identified as soiling, failed modules, and failures in interconnections. System performance evaluation continues to be complicated by the poor reliability of some power conditioning hardware that has greatly diminished the system availability and by inconsistent field ratings. Nevertheless, the current system reliability is consistent with degradation of less than 10% in 5 years and with estimates of less than 10% per year of the energy value for O and M.

  8. Reliability of photovoltaic systems - A field report

    NASA Astrophysics Data System (ADS)

    Thomas, M. G.; Fuentes, M. K.; Lashway, C.; Black, B. D.

    Performance studies and field measurements of photovoltaic systems indicate a 1-2-percent/yr degradation in array energy production. The cause for much of the degradation has been identified as soiling, failed modules, and failures in interconnections. System performance evaluation continues to be complicated by the poor reliability of some power conditioning hardware (which greatly diminished system availability) and by inconsistent field ratings. Nevertheless, the current system reliability is consistent with degradation of less than 10 percent in 5 years and with estimates of less than 10 percent/yr of the energy value for O&M.

  9. Biological systems in high magnetic field

    NASA Astrophysics Data System (ADS)

    Yamagishi, A.

    1990-12-01

    Diamagnetic orientation of biological systems have been investigated theoretically and experimentally. Fibrinogen, one of blood proteins, were polymerized in static high magnetic fields up to 8 T. Clotted gels composed of oriented fibrin fibers were obtained even in a field as low as 1 T. Red blood cells (RBC) show full orientation with their plane parallel to the applied field of 4 T. It is confirmed experimentally that the magnetic orientation of RBC is caused by diamagnetic anisotropy. Full orientation is also obtained with blood platelet in a field of 3 T.

  10. Measured and simulated poloidal asymmetries of the FTU S.O.L. in the toroidal limiter configuration

    NASA Astrophysics Data System (ADS)

    Leigheb, M.; Ridolfini, V. Pericoli; Zagorski, R.

    The scrape-off layer (SOL) of FTU in the magnetic configuration generated by a TZM (Molybdenum) toroidal limiter has been studied by an array of reciprocating Langmuir probes extended over a large part of the poloidal angle, and the results have been compared with the 2-dimensional multifluid SOL code EPIT. A comparison with the previous poloidal limiter configuration with the same main plasma conditions, showed at the last closed magnetic surface (LCMS) longer and more poloidally uniform connection lengths, and a corresponding better uniformity of SOL plasma parameters. Asymmetry of electron density is observed, which can be associated with the recycling of plasma near the toroidal limiter plates in a configuration with long connection lengths. Electron temperature appears to be less dependent of power entering the SOL than in the old poloidal limiter configuration. Experimentally observed dependence of the edge plasma condition on Lcon has been confirmed by the results of the 2D code EPIT.

  11. Indirect measurement of poloidal rotation using inboard-outboard asymmetry of toroidal rotation and comparison with neoclassical predictions

    NASA Astrophysics Data System (ADS)

    Bortolon, A.; Camenen, Y.; Karpushov, A. N.; Duval, B. P.; Andrebe, Y.; Federspiel, L.; Sauter, O.; the TCV Team

    2013-02-01

    An alternative experimental spectroscopic measurement of poloidal plasma rotation in toroidally confined plasmas is proven effective in the TCV tokamak. Charge exchange recombination measurements of the toroidal rotation profile over the full mid-plane plasma diameter are used to infer the complete bi-dimensional flow structure of the intrinsic C6+ impurity, which includes its poloidal component. For divergence free flows, the difference between the toroidal rotation frequency ft = ut/R at the inboard and outboard locations on the same flux surface is proportional to the poloidal rotation. This indirect measurement provides increased accuracy as the measured quantity ft,in - ft,out≈4qup/Raxis(q is the local safety factor) is larger than the intrinsic uncertainties of a direct spectroscopic measurement of poloidal velocity. The method is applied in a variety of TCV ohmic and electron cyclotron heated L-mode plasmas in the banana-plateau collisionality regime (0.2<\

  12. Field Theory for Multi-Particle System

    NASA Astrophysics Data System (ADS)

    Wang, Shouhong; Ma, Tian

    2016-03-01

    The main objectives of this talk are 1) to introduce some basic postulates for quantum multi-particle systems, and 2) to develop a universal field theory for interacting multi-particle systems coupling both particle fields and interacting fields. By carefully examining the nature of interactions between multi-particles, we conclude that multi-particle systems must obey i) the gauge symmetry, ii) the principle of interaction dynamics (PID), and iii) the principle of representation invariance (PRI). Intuitively, PID takes the variation of the action functional under energy-momentum conservation constraint, offers a different and natural way of introducing Higgs fields, and is also required by the presence of dark matter and dark energy and the quark confinement. PRI requires that the SU(N) gauge theory be independent of representations of SU(N). Based on these principles, a few basic postulates for multi-particle systems are introduced in this talk, leading to a field theory for interacting multi-particle systems. A direct consequence of the field theory is the derivation of general atomic spectrum equations. Supported in Part by the Office of Naval Research, by the US National Science Foundation, and by the Chinese National Science Foundation.

  13. Transient electromagnetic fields near large earthing systems

    SciTech Connect

    Grcev, L.D.; Menter, F.E.

    1996-05-01

    Electromagnetic compatibility studies require knowledge of transient voltages that may be developed near earthing systems during lightning discharge, since such voltages may be coupled to sensitive electronic circuits. For such purpose accurate evaluation of transient electric field near to and/or at the surface of the grounding conductors is necessary. In this paper, a procedure for computation of transient fields near large earthing systems, as a response to a typical lightning current impulse, based on computational methodology developed in the field of antennas, is presented. Computed results are favorably compared with published measurement results. The model is applied to check the common assumption that the soil ionization can be neglected in case of large earthing systems. Presented results show that the soil ionization threshold is met and exceeded during typical lightning discharge in a large earthing system.

  14. Electromagnetic field interactions with biological systems

    SciTech Connect

    Frey, A.H. )

    1993-02-01

    This is a report on Symposia organized by the International Society for Bioelectricity and presented at the 1992 FASEB Meeting. The presentations summarized here were intended to provide a sampling of new and fruitful lines of research. The theme topics for the Symposia were cancer, neural function, cell signaling, pineal gland function, and immune system interactions. Living organisms are complex electrochemical systems that evolved over billions of years in a world with a relatively simple weak magnetic field and with few electromagnetic energy emitters. As is characteristic of living organisms, they interacted with and adapted to this environment of electric and magnetic fields. In recent years there has been a massive introduction of equipment that emits electromagnetic fields in an enormous range of new frequencies, modulations, and intensities. As living organisms have only recently found themselves immersed in this new and virtually ubiquitous environment, they have not had the opportunity to adapt to it. This gives biologists the opportunity to use these electromagnetic fields as probes to study the functioning of living systems. This is a significant opportunity, as new approaches to studying living systems so often provide the means to make great leaps in science. In recent years, a diversity of biologists have carried out experiments using electromagnetic fields to study the function of living cells and systems. This approach is now becoming quite fruitful and is yielding data that are advancing our knowledge in diverse areas of biology. 25 refs., 6 figs., 3 tabs.

  15. Pressure and Temperature Sensitive Paint Field System

    NASA Technical Reports Server (NTRS)

    Sprinkle, Danny R.; Obara, Clifford J.; Amer, Tahani R.; Faulcon, Nettie D.; Carmine, Michael T.; Burkett, Cecil G.; Pritchard, Daniel W.; Oglesby, Donald M.

    2004-01-01

    This report documents the Pressure and Temperature Sensitive Paint Field System that is used to provide global surface pressure and temperature measurements on models tested in Langley wind tunnels. The system was developed and is maintained by Global Surface Measurements Team personnel of the Data Acquisition and Information Management Branch in the Research Facilities Services Competency. Descriptions of the system hardware and software are presented and operational procedures are detailed.

  16. Magnetic Field Response Measurement Acquisition System

    NASA Technical Reports Server (NTRS)

    Woodard, Stanley E.; Taylor, Bryant D.; Shams, Qamar A.; Fox, Robert L.

    2005-01-01

    A measurement acquisition method that alleviates many shortcomings of traditional measurement systems is presented in this paper. The shortcomings are a finite number of measurement channels, weight penalty associated with measurements, electrical arcing, wire degradations due to wear or chemical decay and the logistics needed to add new sensors. The key to this method is the use of sensors designed as passive inductor-capacitor circuits that produce magnetic field responses. The response attributes correspond to states of physical properties for which the sensors measure. A radio frequency antenna produces a time-varying magnetic field used to power the sensor and receive the magnetic field response of the sensor. An interrogation system for discerning changes in the sensor response is presented herein. Multiple sensors can be interrogated using this method. The method eliminates the need for a data acquisition channel dedicated to each sensor. Methods of developing magnetic field response sensors and the influence of key parameters on measurement acquisition are discussed.

  17. Broadband antenna systems for lightning magnetic fields

    NASA Technical Reports Server (NTRS)

    Krider, E. P.; Noggle, R. C.

    1975-01-01

    Broadband magnetic antenna systems suitable for recording submicrosecond field changes are described, and typical data from distant lightning are presented. Two types of systems are described, one with a high-impedance antenna loop connected to the integrator by a twisted pair of coaxial cables and another with the antenna loop and twisted signal loops formed from a single piece of coaxial cable. Data for correlated magnetic and electric field waveforms from lightning at a distance of 50 to 100 km are presented and are shown to be almost identical.

  18. An upgrade of the magnetic diagnostic system of the DIII-D tokamak for non-axisymmetric measurements.

    PubMed

    King, J D; Strait, E J; Boivin, R L; Taussig, D; Watkins, M G; Hanson, J M; Logan, N C; Paz-Soldan, C; Pace, D C; Shiraki, D; Lanctot, M J; La Haye, R J; Lao, L L; Battaglia, D J; Sontag, A C; Haskey, S R; Bak, J G

    2014-08-01

    The DIII-D tokamak magnetic diagnostic system [E. J. Strait, Rev. Sci. Instrum. 77, 023502 (2006)] has been upgraded to significantly expand the measurement of the plasma response to intrinsic and applied non-axisymmetric "3D" fields. The placement and design of 101 additional sensors allow resolution of toroidal mode numbers 1 ≤ n ≤ 3, and poloidal wavelengths smaller than MARS-F, IPEC, and VMEC magnetohydrodynamic model predictions. Small 3D perturbations, relative to the equilibrium field (10(-5) < δB/B0 < 10(-4)), require sub-millimeter fabrication and installation tolerances. This high precision is achieved using electrical discharge machined components, and alignment techniques employing rotary laser levels and a coordinate measurement machine. A 16-bit data acquisition system is used in conjunction with analog signal-processing to recover non-axisymmetric perturbations. Co-located radial and poloidal field measurements allow up to 14.2 cm spatial resolution of poloidal structures (plasma poloidal circumference is ~500 cm). The function of the new system is verified by comparing the rotating tearing mode structure, measured by 14 BP fluctuation sensors, with that measured by the upgraded B(R) saddle loop sensors after the mode locks to the vessel wall. The result is a nearly identical 2/1 helical eigenstructure in both cases.

  19. An upgrade of the magnetic diagnostic system of the DIII-D tokamak for non-axisymmetric measurements

    DOE PAGES

    King, Joshua D.; Strait, Edward J.; Boivin, Rejean L.; ...

    2014-08-07

    Here, the DIII-D tokamak magnetic diagnostic system has been upgraded to significantly expand the measurement of the plasma response to intrinsic and applied non-axisymmetric “3D” fields. The placement and design of 101 additional sensors allow resolution of toroidal mode numbers 1 ≤ n ≤ 3, and poloidal wavelengths smaller than MARS-F, IPEC, and VMEC magnetohydrodynamic (MHD) model predictions. Small 3D perturbations, relative to the equilibrium field (10–5 <δB/B0 <10–4), require sub-millimeter fabrication and installation tolerances. This high precision is achieved using electrical discharge machined components, and alignment techniques employing rotary laser levels and a coordinate measurement machine. A 16-bit datamore » acquisition system is used in conjunction with analog signal-processing to recover non-axisymmetric perturbations. Co-located radial and poloidal field measurements allow up to 14.2 cm spatial resolution of poloidal structures (plasma poloidal circumference is ~ 500 cm). The function of the new system is verified by comparing the rotating tearing mode structure, measured by 31 BP fluctuation sensors, with that measured by the upgraded BR saddle loop sensors after the mode locks to the vessel wall. The result is a nearly identical 2/1 helical eigenstructure in both cases.« less

  20. An upgrade of the magnetic diagnostic system of the DIII-D tokamak for non-axisymmetric measurements

    NASA Astrophysics Data System (ADS)

    King, J. D.; Strait, E. J.; Boivin, R. L.; Taussig, D.; Watkins, M. G.; Hanson, J. M.; Logan, N. C.; Paz-Soldan, C.; Pace, D. C.; Shiraki, D.; Lanctot, M. J.; La Haye, R. J.; Lao, L. L.; Battaglia, D. J.; Sontag, A. C.; Haskey, S. R.; Bak, J. G.

    2014-08-01

    The DIII-D tokamak magnetic diagnostic system [E. J. Strait, Rev. Sci. Instrum. 77, 023502 (2006)] has been upgraded to significantly expand the measurement of the plasma response to intrinsic and applied non-axisymmetric "3D" fields. The placement and design of 101 additional sensors allow resolution of toroidal mode numbers 1 ≤ n ≤ 3, and poloidal wavelengths smaller than MARS-F, IPEC, and VMEC magnetohydrodynamic model predictions. Small 3D perturbations, relative to the equilibrium field (10-5 < δB/B0 < 10-4), require sub-millimeter fabrication and installation tolerances. This high precision is achieved using electrical discharge machined components, and alignment techniques employing rotary laser levels and a coordinate measurement machine. A 16-bit data acquisition system is used in conjunction with analog signal-processing to recover non-axisymmetric perturbations. Co-located radial and poloidal field measurements allow up to 14.2 cm spatial resolution of poloidal structures (plasma poloidal circumference is ˜500 cm). The function of the new system is verified by comparing the rotating tearing mode structure, measured by 14 BP fluctuation sensors, with that measured by the upgraded BR saddle loop sensors after the mode locks to the vessel wall. The result is a nearly identical 2/1 helical eigenstructure in both cases.

  1. An upgrade of the magnetic diagnostic system of the DIII-D tokamak for non-axisymmetric measurements

    SciTech Connect

    King, Joshua D.; Strait, Edward J.; Boivin, Rejean L.; Taussig, Doug; Watkins, Matthias G.; Hanson, Jeremy M.; Logan, Nikolas C.; Paz-Soldan, Carlos; Pace, David C.; Shiraki, Daisuke; Lanctot, M. J.; La Haye, R. J.; Lao, L. L.; Battaglia, D. J.; Sontag, A. C.; Haskey, S. R.; Bak, J. G.

    2014-08-07

    Here, the DIII-D tokamak magnetic diagnostic system has been upgraded to significantly expand the measurement of the plasma response to intrinsic and applied non-axisymmetric “3D” fields. The placement and design of 101 additional sensors allow resolution of toroidal mode numbers 1 ≤ n ≤ 3, and poloidal wavelengths smaller than MARS-F, IPEC, and VMEC magnetohydrodynamic (MHD) model predictions. Small 3D perturbations, relative to the equilibrium field (10–5 <δB/B0 <10–4), require sub-millimeter fabrication and installation tolerances. This high precision is achieved using electrical discharge machined components, and alignment techniques employing rotary laser levels and a coordinate measurement machine. A 16-bit data acquisition system is used in conjunction with analog signal-processing to recover non-axisymmetric perturbations. Co-located radial and poloidal field measurements allow up to 14.2 cm spatial resolution of poloidal structures (plasma poloidal circumference is ~ 500 cm). The function of the new system is verified by comparing the rotating tearing mode structure, measured by 31 BP fluctuation sensors, with that measured by the upgraded BR saddle loop sensors after the mode locks to the vessel wall. The result is a nearly identical 2/1 helical eigenstructure in both cases.

  2. Magnetic Field Response Measurement Acquisition System

    NASA Technical Reports Server (NTRS)

    Woodard, Stanley E.; Taylor,Bryant D.; Shams, Qamar A.; Fox, Robert L.

    2007-01-01

    This paper presents a measurement acquisition method that alleviates many shortcomings of traditional measurement systems. The shortcomings are a finite number of measurement channels, weight penalty associated with measurements, electrical arcing, wire degradations due to wear or chemical decay and the logistics needed to add new sensors. Wire degradation has resulted in aircraft fatalities and critical space launches being delayed. The key to this method is the use of sensors designed as passive inductor-capacitor circuits that produce magnetic field responses. The response attributes correspond to states of physical properties for which the sensors measure. Power is wirelessly provided to the sensing element by using Faraday induction. A radio frequency antenna produces a time-varying magnetic field used to power the sensor and receive the magnetic field response of the sensor. An interrogation system for discerning changes in the sensor response frequency, resistance and amplitude has been developed and is presented herein. Multiple sensors can be interrogated using this method. The method eliminates the need for a data acquisition channel dedicated to each sensor. The method does not require the sensors to be near the acquisition hardware. Methods of developing magnetic field response sensors and the influence of key parameters on measurement acquisition are discussed. Examples of magnetic field response sensors and the respective measurement characterizations are presented. Implementation of this method on an aerospace system is discussed.

  3. Fast time resolution charge-exchange measurements during the fishbone instability in the poloidal divertor experiment

    SciTech Connect

    Beiersdorfer, P.; Kaita, R.; Goldston, R.J.

    1984-01-01

    Measurements of fast ion losses due to the fishbone instability during high ..beta../sub T/q neutral beam heated discharges in the Poloidal Divertor Experiment have been made using two new vertical-viewing charge-exchange analyzers. The measurements show that the instability has an n=1 toroidal mode number, and that it ejects beam ions in a toroidally rotating beacon directed outward along a major radius. Observations of ejected ions with energies up to twice the beam injection energy at R approx. = R/sub 0/ + a indicate the presence of a non-..mu..-conserving acceleration mechanism.

  4. Magnetic Field Response Measurement Acquisition System

    NASA Technical Reports Server (NTRS)

    Woodard, Stanley E. (Inventor); Taylor, Bryant D. (Inventor); Shams, Qamar A. (Inventor); Fox, Robert L. (Inventor); Fox, Christopher L. (Inventor); Fox, Melanie L. (Inventor); Bryant, Robert G. (Inventor)

    2006-01-01

    Magnetic field response sensors designed as passive inductor-capacitor circuits produce magnetic field responses whose harmonic frequencies correspond to states of physical properties for which the sensors measure. Power to the sensing element is acquired using Faraday induction. A radio frequency antenna produces the time varying magnetic field used for powering the sensor, as well as receiving the magnetic field response of the sensor. An interrogation architecture for discerning changes in sensor s response kequency, resistance and amplitude is integral to the method thus enabling a variety of measurements. Multiple sensors can be interrogated using this method, thus eliminating the need to have a data acquisition channel dedicated to each sensor. The method does not require the sensors to be in proximity to any form of acquisition hardware. A vast array of sensors can be used as interchangeable parts in an overall sensing system.

  5. Molecular systems in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Turbiner, Alexander V.

    2007-04-01

    Brief overview of one-two electron molecular systems made out of protons and/or α-particles in a strong magnetic field B≤4.414×1013 G is presented. A particular emphasis is given to the one-electron exotic ions H 3 ++ (pppe), He 2 3+ (α α e) and to two-electron ionsH 3 + (pppee), He 2 ++ (α α ee). Quantitative studies in a strong magnetic field are very complicated technically. Novel approach to the few-electron Coulomb systems in magnetic field, which provides accurate results, based on variational calculus with physically relevant trial functions is briefly described.

  6. Advanced control of MST's poloidal field with a programmable power supply

    NASA Astrophysics Data System (ADS)

    Chapman, B. E.; Holly, D. J.; McCollam, K. J.; Morin, J. C.; Sarff, J. S.; Squitieri, A.; Anderson, J. K.; Seltzman, A. H.

    2015-11-01

    One thrust of the MST program is to advance inductive control for the development of both the RFP's fusion potential and the predictive capability of fusion science. This entails programmable power supplies (PPS's) for the Bt and Bp circuits. A Bt PPS is in place, and a Bp PPS is being designed. Together, these supplies will provide inductive capability rivaling that of any fusion device in the world. To better inform the design of the Bp PPS, and to demonstrate some of the new capabilities that will be provided, the existing Bt PPS has been connected to MST's Bp circuit. While limited to lower voltage and current than the planned Bp PPS, this has already more than quadrupled the Ip flattop duration. It has also allowed access to very low Ip, down to 20 kA, substantially increasing MST's range of Lundquist number, important for the validation of MHD computational models. Low Ip has also allowed electron energization by high-harmonic EBW. At higher Ip, work has begun on self-similar ramp-down of Ip, a potential route to improved confinement. Work supported by U.S.D.O.E.

  7. Thermalization of field driven quantum systems

    PubMed Central

    Fotso, H.; Mikelsons, K.; Freericks, J. K.

    2014-01-01

    There is much interest in how quantum systems thermalize after a sudden change, because unitary evolution should preclude thermalization. The eigenstate thermalization hypothesis resolves this because all observables for quantum states in a small energy window have essentially the same value; it is violated for integrable systems due to the infinite number of conserved quantities. Here, we show that when a system is driven by a DC electric field there are five generic behaviors: (i) monotonic or (ii) oscillatory approach to an infinite-temperature steady state; (iii) monotonic or (iv) oscillatory approach to a nonthermal steady state; or (v) evolution to an oscillatory state. Examining the Hubbard model (which thermalizes under a quench) and the Falicov-Kimball model (which does not), we find both exhibit scenarios (i–iv), while only Hubbard shows scenario (v). This shows richer behavior than in interaction quenches and integrability in the absence of a field plays no role. PMID:24736404

  8. Electric Field Quantitative Measurement System and Method

    NASA Technical Reports Server (NTRS)

    Generazio, Edward R. (Inventor)

    2016-01-01

    A method and system are provided for making a quantitative measurement of an electric field. A plurality of antennas separated from one another by known distances are arrayed in a region that extends in at least one dimension. A voltage difference between at least one selected pair of antennas is measured. Each voltage difference is divided by the known distance associated with the selected pair of antennas corresponding thereto to generate a resulting quantity. The plurality of resulting quantities defined over the region quantitatively describe an electric field therein.

  9. Magnetic Field Response Measurement Acquisition System

    NASA Technical Reports Server (NTRS)

    Woodward, Stanley E. (Inventor); Taylor, Bryant D. (Inventor)

    2007-01-01

    Magnetic field response sensors designed as passive inductor- capacit or circuits produce magnetic field responses whose harmonic frequenci es correspond to states of physical properties for which the sensors measure. Power to the sensing element is acquired using Faraday induc tion. A radio frequency antenna produces the time varying magnetic fi eld used for powering the sensor, as well as receiving the magnetic field response of the sensor. An interrogation architecture for disce rning changes in sensor's response frequency, resistance and amplitud e is integral to the method thus enabling a variety of measurements. Multiple sensors can be interrogated using this method, thus eliminat ing the need to have a data acquisition channel dedicated to each se nsor. The method does not require the sensors to be in proximity to a ny form of acquisition hardware. A vast array of sensors can be used as interchangeable parts in an overall sensing system.

  10. Magnetic field regulation control system analysis

    SciTech Connect

    Badelt, Steven W.

    1996-05-01

    This study comprises (1) an analytical characterization of the Cameca ion microscope`s magnetic field regulation circuitry and (2) comparisons between the analytical predictions and the measured performance of the control system. It is the first step in a project to achieve routine field regulation better than 10ppm. The control loop was decomposed into functional subcircuits and simulated in SPICE to determine DC, AC, and transient response. Transfer functions were extracted from SPICE, simplified, and analyzed in MATLAB. Both SPICE and MATLAB simulations were calculated for step inputs, and these results were compared to actual measurements. Magnetic field fluctuations were measured at high mass resolving power. The frequency spectrum of the fluctuations was analyzed by FFT. Difficulties encountered and implications for future work are discussed.

  11. High-beta analytic equilibria in circular, elliptical, and D-shaped large aspect ratio axisymmetric configurations with poloidal and toroidal flows

    NASA Astrophysics Data System (ADS)

    López, O. E.; Guazzotto, L.

    2017-03-01

    The Grad-Shafranov-Bernoulli system of equations is a single fluid magnetohydrodynamical description of axisymmetric equilibria with mass flows. Using a variational perturbative approach [E. Hameiri, Phys. Plasmas 20, 024504 (2013)], analytic approximations for high-beta equilibria in circular, elliptical, and D-shaped cross sections in the high aspect ratio approximation are found, which include finite toroidal and poloidal flows. Assuming a polynomial dependence of the free functions on the poloidal flux, the equilibrium problem is reduced to an inhomogeneous Helmholtz partial differential equation (PDE) subject to homogeneous Dirichlet conditions. An application of the Green's function method leads to a closed form for the circular solution and to a series solution in terms of Mathieu functions for the elliptical case, which is valid for arbitrary elongations. To extend the elliptical solution to a D-shaped domain, a boundary perturbation in terms of the triangularity is used. A comparison with the code FLOW [L. Guazzotto et al., Phys. Plasmas 11(2), 604-614 (2004)] is presented for relevant scenarios.

  12. Calculation of poloidal velocity in the tokamak plasma with allowance for density inhomogeneity and diamagnetic drift of ions

    SciTech Connect

    Shurygin, R. V.

    2012-02-15

    A one-dimensional evolution equation for the angle-averaged poloidal momentum of the tokamak plasma is derived in the framework of reduced magnetohydrodynamics with allowance for density inhomogeneity and diamagnetic drift of ions. In addition to fluctuations of the E Multiplication-Sign B drift velocity, the resulting turbulent Reynolds stress tensor includes fluctuations of the ion density and ion pressure, as well as turbulent radial fluxes of particles and heat. It is demonstrated numerically by using a particular example that the poloidal velocity calculated using the refined one-dimensional evolution equation differs substantially from that provided by the simplified model. When passing to the new model, both the turbulent Reynolds force and the Stringer-Winsor force increase, which leads to an increase in the amplitude of the ion poloidal velocity. This, in turn, leads to a decrease in turbulent fluxes of particles and heat due to the effect of shear decorrelation.

  13. Aerodynamic Flow Field Measurements for Automotive Systems

    NASA Technical Reports Server (NTRS)

    Hepner, Timothy E.

    1999-01-01

    The design of a modern automotive air handling system is a complex task. The system is required to bring the interior of the vehicle to a comfortable level in as short a time as possible. A goal of the automotive industry is to predict the interior climate of an automobile using advanced computational fluid dynamic (CFD) methods. The development of these advanced prediction tools will enable better selection of engine and accessory components. The goal of this investigation was to predict methods used by the automotive industry. To accomplish this task three separate experiments were performed. The first was a laboratory setup where laser velocimeter (LV) flow field measurements were made in the heating and air conditioning unit of a Ford Windstar. The second involved flow field measurements in the engine compartment of a Ford Explorer, with the engine running idle. The third mapped the flow field exiting the center dashboard panel vent inside the Explorer, while the circulating fan operated at 14 volts. All three experiments utilized full-coincidence three-component LV systems. This enabled the mean and fluctuating velocities to be measured along with the Reynolds stress terms.

  14. NCSX Toroidal Field Coil Design

    SciTech Connect

    Kalish, M.; Rushinski, J.; Myatt, L.; Brooks, A.; Dahlgren, F.; Chrzanowski, J.; Reiersen, W.; Freudenberg, K.

    2005-10-07

    The National Compact Stellarator Experiment (NCSX) is an experimental device whose design and construction is underway at the Department of Energy's Princeton Plasma Physics Laboratory (PPPL). The primary coil systems for the NCSX device consist of the twisted plasma-shaping Modular Coils, the Poloidal Field Coils, and the Toroidal Field (TF) Coils. The TF Coils are D-shaped coils wound from hollow copper conductor, and vacuum impregnated with a glass-epoxy resin system. There are 18 identical, equally spaced TF coils providing 1/R field at the plasma. They operate within a cryostat, and are cooled by LN2, nominally, to 80K. Wedge shaped castings are assembled to the inboard face of these coils, so that inward radial loads are reacted via the nesting of each of the coils against their adjacent partners. This paper outlines the TF Coil design methodology, reviews the analysis results, and summarizes how the design and analysis support the design requirements.

  15. Magnetic Field Experiment Data Analysis System

    NASA Technical Reports Server (NTRS)

    Holland, D. B.; Zanetti, L. J.; Suther, L. L.; Potemra, T. A.; Anderson, B. J.

    1995-01-01

    The Johns Hopkins University Applied Physics Laboratory (JHU/APL) Magnetic Field Experiment Data Analysis System (MFEDAS) has been developed to process and analyze satellite magnetic field experiment data from the TRIAD, MAGSAT, AMPTE/CCE, Viking, Polar BEAR, DMSP, HILAT, UARS, and Freja satellites. The MFEDAS provides extensive data management and analysis capabilities. The system is based on standard data structures and a standard user interface. The MFEDAS has two major elements: (1) a set of satellite unique telemetry processing programs for uniform and rapid conversion of the raw data to a standard format and (2) the program Magplot which has file handling, data analysis, and data display sections. This system is an example of software reuse, allowing new data sets and software extensions to be added in a cost effective and timely manner. Future additions to the system will include the addition of standard format file import routines, modification of the display routines to use a commercial graphics package based on X-Window protocols, and a generic utility for telemetry data access and conversion.

  16. Deuterium-tritium TFTR plasmas in the high poloidal beta regime

    SciTech Connect

    Sabbagh, S.A.; Mauel, M.E.; Navratil, G.A.

    1995-03-01

    Deuterium-tritium plasmas with enhanced energy confinement and stability have been produced in the high poloidal beta, advanced tokamak regime in TFTR. Confinement enhancement H {triple_bond} {tau}{sub E}/{tau}{sub E ITER-89P} > 4 has been obtained in a limiter H-mode configuration at moderate plasma current I{sub p} = 0.85 {minus} 1.46 MA. By peaking the plasma current profile, {beta}{sub N dia} {triple_bond} 10{sup 8} < {beta}{sub t{perpendicular}} > aB{sub 0}/I{sub p} = 3 has been obtained in these plasma,s exceeding the {beta}{sub N} limit for TFTR plasmas with lower internal inductance, l{sub i}. Fusion power exceeding 6.7 MW with a fusion power gain Q{sub DT} = 0.22 has been produced with reduced alpha particle first orbit loss provided by the increased l{sub i}.

  17. Field testing of the Cobra Seal System

    SciTech Connect

    Yellin, E.; Vodrazka, P. ); Ystesund, K.; Drayer, D. )

    1990-01-01

    The Cobra Seal System consists of a passive fiber optic seal and verification equipment which have been modified to take advantage of current technology. The seal permits on-site verification without requiring replacement of the seal. The modifications to the original Cobra Seal System extended the maximum fiber optic cable length from 1 meter to 10 meters. This improvement allowed the Cobra Seal to be considered for application on dry irradiated fuel storage canisters at two Canadian facilities. These canisters are located in an exterior environment exposed to extreme weather conditions. This paper describe the application of the Cobra Seal to these canisters, a housing for the protection of the Cobra Seal body from the environment, and some preliminary results of the IAEA field tests. 4 refs.

  18. Narrow field electromagnetic sensor system and method

    DOEpatents

    McEwan, Thomas E.

    1996-01-01

    A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor system also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments.

  19. Narrow field electromagnetic sensor system and method

    DOEpatents

    McEwan, T.E.

    1996-11-19

    A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor system also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments. 12 figs.

  20. Loss of beam ions to the inside of the PDX (Poloidal Divertor Experiment) tokamak during the fishbone instability

    SciTech Connect

    Heidbrink, W.W.; Beiersdorfer, P.

    1986-11-01

    Using data from two vertical charge-exchange detectors on the Poloidal Divertor Experiment (PDX), we have identified a set of conditions for which loss of beam ions inward in major radius is observed during the fishbone instability. Previously, it was reported that beam ions were lost only to the outside of the PDX tokamak.

  1. Global Positioning System Simulator Field Operational Procedures

    NASA Technical Reports Server (NTRS)

    Kizhner, Semion; Quinn, David A.; Day, John H. (Technical Monitor)

    2002-01-01

    Global Positioning System (GPS) simulation is an important activity in the development or qualification of GPS signal receivers for space flight. Because a GPS simulator is a critical resource it is highly desirable to develop a set of field operational procedures to supplement the basic procedures provided by most simulator vendors. Validated field procedures allow better utilization of the GPS simulator in the development of new test scenarios and simulation operations. These procedures expedite simulation scenario development while resulting in scenarios that are more representative of the true design, as well as enabling construction of more complex simulations than previously possible, for example, spacecraft maneuvers. One difficulty in the development of a simulation scenario is specifying various modes of test vehicle motion and associated maneuvers requiring that a user specify some (but not all) of a few closely related simulation parameters. Currently this can only be done by trial and error. A stand-alone procedure that implements the simulator maneuver motion equations and solves for the motion profile transient times, jerk and acceleration would be of considerable value. Another procedure would permit the specification of some configuration parameters that would determine the simulated GPS signal composition. The resulting signal navigation message, for example, would force the receiver under test to use only the intended C-code component of the simulated GPS signal. A representative class of GPS simulation-related field operational procedures is described in this paper. These procedures were developed and used in support of GPS integration and testing for many successful spacecraft missions such as SAC-A, EO-1, AMSAT, VCL, SeaStar, sounding rockets, and by using the industry standard Spirent Global Simulation Systems Incorporated (GSSI) STR series simulators.

  2. Mobile Munitions Assessment System Field Capabilities

    SciTech Connect

    A. M. Snyder; D. A. Verrill; K. D. Watts

    1999-05-27

    The US has developed, stored, tested, and conducted disposal operations on various forms of chemical munitions for several decades. The remnants of these activities have resulted in the presence of suspect CWM at more than 200 sites in the US, the District of Columbia, and the US Virgin Islands. An advanced Mobile Munitions Assessment System (Phase II MMAS) has been designed, fabricated, assembled, and tested by the Idaho National Engineering and Environmental Laboratory under contract to the US Army's Project Manager for Non-Stockpile Chemical Materiel for use in the assessment and characterization of ''non-stockpile'' chemical warfare materiel (CWM). The Phase II MMAS meets the immediate need to augment response equipment currently used by the US Army with a system that includes state-of-the-art assessment equipment and advanced sensors. The Phase II MMAS will be used for response to known storage and remediation sites. This system is designed to identify the munition type; evaluate the condition of the CWM; evaluate the environmental conditions in the vicinity of the CWM; determine if fuzes, bursters, or safety and arming devices are in place; identify the chemical fill; provide other data (e.g., meteorological data) necessary for assessing the risk associated with handling, transporting, and disposing of CWM; and record the data on a dedicated computer system. The Phase II MMAS is capable of over-the-road travel and air transport to any site for conducting rigorous assessments of suspect CWM. The Phase II MMAS utilizes a specially-designed commercial motor home to provide a means to transport an interactive network of non-intrusive characterization and assessment equipment. The assessment equipment includes radiography systems, a gamma densitometer system, a Portable Isotopic Neutron Spectroscopy (PINS) system, a Secondary Ion Mass Spectroscopy (SIMS) system, air monitoring equipment (i.e., M-90s and a field ion spectroscopy system), and a phase determination

  3. Magnetic Field Topology in Jets

    NASA Technical Reports Server (NTRS)

    Gardiner, T. A.; Frank, A.

    2000-01-01

    We present results on the magnetic field topology in a pulsed radiative. jet. For initially helical magnetic fields and periodic velocity variations, we find that the magnetic field alternates along the, length of the jet from toroidally dominated in the knots to possibly poloidally dominated in the intervening regions.

  4. Field Testing of Environmentally Friendly Drilling System

    SciTech Connect

    David Burnett

    2009-05-31

    The Environmentally Friendly Drilling (EFD) program addresses new low-impact technology that reduces the footprint of drilling activities, integrates light weight drilling rigs with reduced emission engine packages, addresses on-site waste management, optimizes the systems to fit the needs of a specific development sites and provides stewardship of the environment. In addition, the program includes industry, the public, environmental organizations, and elected officials in a collaboration that addresses concerns on development of unconventional natural gas resources in environmentally sensitive areas. The EFD program provides the fundamentals to result in greater access, reasonable regulatory controls, lower development cost and reduction of the environmental footprint associated with operations for unconventional natural gas. Industry Sponsors have supported the program with significant financial and technical support. This final report compendium is organized into segments corresponding directly with the DOE approved scope of work for the term 2005-2009 (10 Sections). Each specific project is defined by (a) its goals, (b) its deliverable, and (c) its future direction. A web site has been established that contains all of these detailed engineering reports produced with their efforts. The goals of the project are to (1) identify critical enabling technologies for a prototype low-impact drilling system, (2) test the prototype systems in field laboratories, and (3) demonstrate the advanced technology to show how these practices would benefit the environment.

  5. AE activity during transient beta drops in high poloidal beta discharges

    NASA Astrophysics Data System (ADS)

    Huang, J.; Gong, X. Z.; Ren, Q. L.; Ding, S. Y.; Qian, J. P.; Pan, C. K.; Li, G. Q.; Heidbrink, W. W.; Garofalo, A. M.; McClenaghan, J.

    2016-10-01

    Enhanced AE activity has been observed during transient beta drops in high poloidal beta DIII-D discharges with internal transport barriers (ITBs). These drops in beta are believed to be caused by n=1 external kink modes. In some discharges, beta recovers within 200 ms but, in others, beta stays suppressed. A typical discharge has βP 3, qmin 3, and q95 12. The drop in beta affects both fast ions and thermal particles, and a drop is also observed in the density and rotation. The enhanced AE activity follows the instability that causes the beta drop, is largest at the lowest beta, and subsides as beta recovers. MHD stability analysis is planned. A database study of the plasma conditions associated with the collapse will be also presented. Supported in part by the US Department of Energy under DE-FC02-04ER54698, DE-AC05-06OR23100, and by the National Natural Science Foundation of China 11575249, and the National Magnetic Confinement Fusion Program of China No. 2015GB110005.

  6. Cooperative field test program for wind systems

    SciTech Connect

    Bollmeier, W.S. II; Dodge, D.M.

    1992-03-01

    The objectives of the Federal Wind Energy Program, managed by the US Department of Energy (DOE), are (1) to assist industry and utilities in achieving a multi-regional US market penetration of wind systems, and (2) to establish the United States as the world leader in the development of advanced wind turbine technology. In 1984, the program conducted a series of planning workshops with representatives from the wind energy industry to obtain input on the Five-Year Research Plan then being prepared by DOE. One specific suggestion that came out of these meetings was that the federal program should conduct cooperative research tests with industry to enhance the technology transfer process. It was also felt that the active involvement of industry in DOE-funded research would improve the state of the art of wind turbine technology. DOE established the Cooperative Field Test Program (CFTP) in response to that suggestion. This program was one of the first in DOE to feature joint industry-government research test teams working toward common objectives.

  7. Classical chaos in atom-field systems.

    PubMed

    Chávez-Carlos, J; Bastarrachea-Magnani, M A; Lerma-Hernández, S; Hirsch, J G

    2016-08-01

    The relation between the onset of chaos and critical phenomena, like quantum phase transitions (QPTs) and excited-state quantum phase transitions (ESQPTs), is analyzed for atom-field systems. While it has been speculated that the onset of hard chaos is associated with ESQPTs based in the resonant case, the off-resonant cases, and a close look at the vicinity of the QPTs in resonance, show clearly that both phenomena, ESQPTs and chaos, respond to different mechanisms. The results are supported in a detailed numerical study of the dynamics of the semiclassical Hamiltonian of the Dicke model. The appearance of chaos is quantified calculating the largest Lyapunov exponent for a wide sample of initial conditions in the whole available phase space for a given energy. The percentage of the available phase space with chaotic trajectories is evaluated as a function of energy and coupling between the qubit and bosonic part, allowing us to obtain maps in the space of coupling and energy, where ergodic properties are observed in the model. Different sets of Hamiltonian parameters are considered, including resonant and off-resonant cases.

  8. Reduction of poloidal magnetic flux consumption during plasma current ramp-up in DEMO relevant plasma regimes

    NASA Astrophysics Data System (ADS)

    Wakatsuki, T.; Suzuki, T.; Hayashi, N.; Shiraishi, J.; Sakamoto, Y.; Ide, S.; Kubo, H.; Kamada, Y.

    2017-01-01

    The method for reducing a poloidal magnetic flux consumption of external coils is investigated to reduce the size of the central solenoid (CS) in the DEMO reactor. The reduction of the poloidal magnetic flux consumption during a plasma current ramp-up phase by electron cyclotron (EC) heating is investigated using an integrated modeling code suite, TOPICS. A strongly reversed shear q profile tends to be produced if intense off-axis EC heating is applied to obtain a large reduction of the flux consumption. In order to overcome this tendency, we find a method to obtain the optimum temperature profile which minimizes the poloidal flux consumption for a wide range of the q profile. We try to reproduce the optimum temperature profile for a weakly reversed shear q profile using six EC rays of 20 MW. As a result, the resistive flux consumption during the current ramp-up can be reduced by 63% from the estimation using the Ejima constant of 0.45 and the total flux consumption can be reduced by 20% from the conventional estimation. In addition, we find that the resistive flux consumption is closely related to the volume averaged electron temperature and not to the profile shape. Using this relation, the required heating power is estimated to be 31 MW based on a well established global confinement scaling, ITER L-89P. As a result, it is clarified that the poloidal magnetic flux consumption can be reduced by 20% using 20-31 MW of EC heating for a weakly reversed shear q profile. This reduction of the flux consumption accounts for 10% reduction of the CS radius.

  9. Main Cause of the Poloidal Plasma Motion Inside a Magnetic Cloud Inferred from Multiple-Spacecraft Observations

    NASA Astrophysics Data System (ADS)

    Zhao, Ake; Wang, Yuming; Chi, Yutian; Liu, Jiajia; Shen, Chenglong; Liu, Rui

    2017-04-01

    Although the dynamical evolution of magnetic clouds (MCs) has been one of the foci of interplanetary physics for decades, only few studies focus on the internal properties of large-scale MCs. Recent work by Wang et al. ( J. Geophys. Res. 120, 1543, 2015) suggested the existence of the poloidal plasma motion in MCs. However, the main cause of this motion is not clear. In order to find it, we identify and reconstruct the MC observed by the Solar Terrestrial Relations Observatory (STEREO)-A, Wind, and STEREO-B spacecraft during 19 - 20 November 2007 with the aid of the velocity-modified cylindrical force-free flux-rope model. We analyze the plasma velocity in the plane perpendicular to the MC axis. It is found that there was evident poloidal motion at Wind and STEREO-B, but this was not clear at STEREO-A, which suggests a local cause rather than a global cause for the poloidal plasma motion inside the MC. The rotational directions of the solar wind and MC plasma at the two sides of the MC boundary are found to be consistent, and the values of the rotational speeds of the solar wind and MC plasma at the three spacecraft show a rough correlation. All of these results illustrate that the interaction with ambient solar wind through viscosity might be one of the local causes of the poloidal motion. Additionally, we propose another possible local cause: the existence of a pressure gradient in the MC. The significant difference in the total pressure at the three spacecraft suggests that this speculation is perhaps correct.

  10. Field Turf System Has Irrigation Down PAT

    ERIC Educational Resources Information Center

    Day, C. William

    1973-01-01

    Explains the process whereby Goshen High School (Indiana) acquired a football field that is never muddy, but which is never covered with expensive sheeting; and that has green grass the year around, but which no one ever sprinkles. It also offers firmness for running, resiliency for falling, traction for turning, and a flat, highly uniform field.…

  11. Zonal Flow Magnetic Field Interaction in the Semi-Conducting Region of Giant Planets

    NASA Astrophysics Data System (ADS)

    Cao, Hao; Stevenson, David J.

    2016-10-01

    All four giant planets in the Solar System feature zonal flows on the order of 100 m/s in the cloud deck, and large-scale intrinsic magnetic fields on the order of 1 Gauss near the surface. The vertical structure of the zonal flows remains obscure. The end-member scenarios are shallow flows confined in the radiative atmosphere and deep flows throughout the planet with constant velocity along the direction of the spin-axis. The electrical conductivity increases smoothly as a function of depth inside Jupiter and Saturn, while a discontinuity of electrical conductivity inside Uranus and Neptune cannot be ruled out. Deep zonal flows will inevitably interact with the magnetic field, at depth with even modest electrical conductivity. Here we investigate the interaction between zonal flows and magnetic fields in the semi-conducting region of giant planets. Employing mean-field electrodynamics, we show that the interaction will generate detectable poloidal magnetic field perturbations spatially correlated with the deep zonal flows. Assuming the peak amplitude of the dynamo α-effect to be 0.1 mm/s, deep zonal flows on the order of 0.1 - 1 m/s in the semi-conducting region of Jupiter and Saturn would generate poloidal magnetic perturbations on the order of 0.01 % - 1 % of the background dipole field. These poloidal perturbations should be detectable with the in-situ magnetic field measurements from the upcoming Juno mission and the Cassini Grand Finale. This implies that magnetic field measurements can be employed to constrain the properties of deep zonal flows in the semi-conducting region of giant planets.

  12. The topology of integrable systems with incomplete fields

    SciTech Connect

    Aleshkin, K R

    2014-09-30

    Liouville's theorem holds for Hamiltonian systems with complete Hamiltonian fields which possess a complete involutive system of first integrals; such systems are called Liouville-integrable. In this paper integrable systems with incomplete Hamiltonian fields are investigated. It is shown that Liouville's theorem remains valid in the case of a single incomplete field, while if the number of incomplete fields is greater, a certain analogue of the theorem holds. An integrable system on the algebra sl(3) is taken as an example. Bibliography: 11 titles.

  13. QM-8 field joint protection system, volume 7

    NASA Technical Reports Server (NTRS)

    Hale, Elgie

    1989-01-01

    The pre-launch functioning data of the Field Joint Protection System (JPS) used on QM-8 are presented. Also included is the post fire condition of the JPS components following the test firing of the motor. The JPS components are: field joint heaters; field joint sensors; field joint moisture seal; moisture seal kevlar retaining straps; field joint external extruded cork insulation; vent valve; power cables; and igniter heater.

  14. The system analysis of light field information collection based on the light field imaging

    NASA Astrophysics Data System (ADS)

    Wang, Ye; Li, Wenhua; Hao, Chenyang

    2016-10-01

    Augmented reality(AR) technology is becoming the study focus, and the AR effect of the light field imaging makes the research of light field camera attractive. The micro array structure was adopted in most light field information acquisition system(LFIAS) since emergence of light field camera, micro lens array(MLA) and micro pinhole array(MPA) system mainly included. It is reviewed in this paper the structure of the LFIAS that the Light field camera commonly used in recent years. LFIAS has been analyzed based on the theory of geometrical optics. Meanwhile, this paper presents a novel LFIAS, plane grating system, we call it "micro aperture array(MAA." And the LFIAS are analyzed based on the knowledge of information optics; This paper proves that there is a little difference in the multiple image produced by the plane grating system. And the plane grating system can collect and record the amplitude and phase information of the field light.

  15. Charge exchange recombination spectroscopy on a diagnostic hydrogen beam—measuring impurity rotation and radial electric field at the tokamak TEXTOR

    NASA Astrophysics Data System (ADS)

    Coenen, J. W.; Schweer, B.; Clever, M.; Freutel, S.; Schmitz, O.; Stoschus, H.; Samm, U.; Unterberg, B.

    2010-07-01

    In this work we present an overview on the charge exchange recombination spectroscopy (CXRS) diagnostic operated with the modulated diagnostic hydrogen beam at the tokamak TEXTOR. The diagnostic setup combines two observation systems used for the measurement of the poloidal (vpol) and the toroidal (vtor) ion velocity component. At TEXTOR a differential Doppler spectroscopy approach (accurate absolute rotation scale) is combined with the high intensity and spatial resolution of a direct imaging system necessary for accurate poloidal rotation measurements on a shot-by-shot basis. This setup allows the full utilization of a 2D CCD detector in the spectral and radial direction. In the case of the poloidal system this allows spatial resolution in the range of mm to cm depending on the intensity requirements for the velocity. The toroidal system comprises a fibre-optic array. The combination of the two measurements with a low-power diagnostic beam can in principle be operated during any available heating scenario without interfering with the discharge. Time resolution is limited by the necessary averaging process; typically a stable plateau of 3 s during a TETXOR pulse is used. The TEXTOR tokamak has the ability to apply momentum input with two tangential neutral beam heating injectors, allowing for measurements under various heating and momentum input scenarios. With the presented diagnostic half the plasma minor radius at a spatial resolution of {\\sim} 1\\,\\rm cm is covered. With the CVI line at 529.053 nm an accuracy of 0.7\\, \\rm km\\,s^{-1} for the poloidal and ~5 \\rm km\\,s^{-1} for the toroidal system is given. The temperature is measured with an accuracy of a few eV. The presented work illustrates the capability of the system during a toroidal momentum scan, showing the self-consistent determination of the radial electric field from experimental CXRS data based on the radial force balance.

  16. Comparison study of toroidal-field divertors for a compact reversed-field pinch reactor

    SciTech Connect

    Bathke, C.G.; Krakowski, R.A.; Miller, R.L.

    1985-01-01

    Two divertor configurations for the Compact Reversed-Field Pinch Reactor (CRFPR) based on diverting the minority (toroidal) field have been reported. A critical factor in evaluating the performance of both poloidally symmetric and bundle divertor configurations is the accurate determination of the divertor connection length and the monitoring of magnetic islands introduced by the divertors, the latter being a three-dimensional effect. To this end the poloidal-field, toroidal-field, and divertor coils and the plasma currents are simulated in three dimensions for field-line tracings in both the divertor channel and the plasma-edge regions. The results of this analysis indicate a clear preference for the poloidally symmetric toroidal-field divertor. Design modifications to the limiter-based CRFPR design that accommodate this divertor are presented.

  17. Lyapunov Control of Quantum Systems with Impulsive Control Fields

    PubMed Central

    Yang, Wei; Sun, Jitao

    2013-01-01

    We investigate the Lyapunov control of finite-dimensional quantum systems with impulsive control fields, where the studied quantum systems are governed by the Schrödinger equation. By three different Lyapunov functions and the invariant principle of impulsive systems, we study the convergence of quantum systems with impulsive control fields and propose new results for the mentioned quantum systems in the form of sufficient conditions. Two numerical simulations are presented to illustrate the effectiveness of the proposed control method. PMID:23766712

  18. PV system field experience and reliability

    NASA Astrophysics Data System (ADS)

    Durand, Steven; Rosenthal, Andrew; Thomas, Mike

    1997-02-01

    Hybrid power systems consisting of battery inverters coupled with diesel, propane, or gasoline engine-driven electrical generators, and photovoltaic arrays are being used in many remote locations. The potential cost advantages of hybrid systems over simple engine-driven generator systems are causing hybrid systems to be considered for numerous applications including single-family residential, communications, and village power. This paper discusses the various design constraints of such systems and presents one technique for reducing hybrid system losses. The Southwest Technology Development Institute under contract to the National Renewable Energy Laboratory and Sandia National Laboratories has been installing data acquisition systems (DAS) on a number of small and large hybrid PV systems. These systems range from small residential systems (1 kW PV - 7 kW generator), to medium sized systems (10 kW PV - 20 kW generator), to larger systems (100 kW PV - 200 kW generator). Even larger systems are being installed with hundreds of kilowatts of PV modules, multiple wind machines, and larger diesel generators.

  19. A Novel Variable Field System for Field-Cycled Dynamic Nuclear Polarization Spectroscopy

    PubMed Central

    Shet, Keerthi; Caia, George L.; Kesselring, Eric; Samouilov, Alexandre; Petryakov, Sergey; Lurie, David J.; Zweier, Jay L.

    2014-01-01

    Dynamic nuclear polarization (DNP) is an NMR-based technique which enables detection and spectral characterization of endogenous and exogenous paramagnetic substances measured via transfer of polarization from the saturated unpaired electron spin system to the NMR active nuclei. A variable field system capable of performing DNP spectroscopy with NMR detection at any magnetic field in the range 0 - 0.38 T is described. The system is built around a clinical open-MRI system. To obtain EPR spectra via DNP, partial cancellation of the detection field B0NMR is required to alter the evolution field B0EPR at which the EPR excitation is achieved. The addition of resistive actively shielded field cancellation coils in the gap of the primary magnet provides this field offset in the range of 0–100 mT. A description of the primary magnet, cancellation coils, power supplies, interfacing hardware, RF electronics and console are included. Performance of the instrument has been evaluated by acquiring DNP spectra of phantoms with aqueous nitroxide solutions (TEMPOL) at three NMR detection fields of 97 G, 200 G and 587 G corresponding to 413 kHz, 851.6 kHz and 2.5 MHz respectively and fixed EPR evolution field of 100 G corresponding to an irradiation frequency of 282.3 MHz. This variable field DNP system offers great flexibility for the performance of DNP spectroscopy with independent optimum choice of EPR excitation and NMR detection fields. PMID:20570197

  20. Effect of zero magnetic field on cardiovascular system and microcirculation

    NASA Astrophysics Data System (ADS)

    Gurfinkel, Yu. I.; At'kov, O. Yu.; Vasin, A. L.; Breus, T. K.; Sasonko, M. L.; Pishchalnikov, R. Yu.

    2016-02-01

    The effects of zero magnetic field conditions on cardiovascular system of healthy adults have been studied. In order to generate zero magnetic field, the facility for magnetic fields modeling ;ARFA; has been used. Parameters of the capillary blood flow, blood pressure, and the electrocardiogram (ECG) monitoring were measured during the study. All subjects were tested twice: in zero magnetic field and, for comparison, in sham condition. The obtained results during 60 minutes of zero magnetic field exposure demonstrate a clear effect on cardiovascular system and microcirculation. The results of our experiments can be used in studies of long-term stay in hypo-magnetic conditions during interplanetary missions.

  1. Photovoltaic-Powered Vaccine Refrigerator: Freezer Systems Field Test Results

    NASA Technical Reports Server (NTRS)

    Ratajczak, A. F.

    1985-01-01

    A project to develop and field test photovoltaic-powered refrigerator/freezers suitable for vaccine storage was undertaken. Three refrigerator/freezers were qualified; one by Solar Power Corp. and two by Solvolt. Follow-on contracts were awarded for 19 field test systems and for 10 field test systems. A total of 29 systems were installed in 24 countries between October 1981 and October 1984. The project, systems descriptions, installation experiences, performance data for the 22 systems for which field test data was reported, an operational reliability summary, and recommendations relative to system designs and future use of such systems are explained. Performance data indicate that the systems are highly reliable and are capable of maintaining proper vaccine storage temperatures in a wide range of climatological and user environments.

  2. MAPLE Procedures For Boson Fields System On Curved Space - Time

    SciTech Connect

    Murariu, Gabriel

    2007-04-23

    Systems of interacting boson fields are an important subject in the last years. From the problem of dark matter to boson stars' study, boson fields are involved. In the general configuration, it is considered a Klein-Gordon-Maxwell-Einstein fields system for a complex scalar field minimally coupled to a gravitational one. The necessity of studying a larger number of space-time configurations and the huge volume of computations for each particular situation are some reasons for building a MAPLE procedures set for this kind of systems.

  3. Wide field strip-imaging optical system

    NASA Technical Reports Server (NTRS)

    Vaughan, Arthur H. (Inventor)

    1994-01-01

    A strip imaging wide angle optical system is provided. The optical system is provided with a 'virtual' material stop to avoid aberrational effects inherent in wide angle optical systems. The optical system includes a spherical mirror section for receiving light from a 180-degree strip or arc of a target image. Light received by the spherical mirror section is reflected to a frusto-conical mirror section for subsequent rereflection to a row of optical fibers. Each optical fiber transmits a portion of the received light to a detector. The optical system exploits the narrow cone of acceptance associated with optical fibers to substantially eliminate vignetting effects inherent in wide-angle systems. Further, the optical system exploits the narrow cone of acceptance of the optical fibers to substantially limit spherical aberration. The optical system is ideally suited for any application wherein a 180-degree strip image need be detected, and is particularly well adapted for use in hostile environments such as in planetary exploration.

  4. Development of field portable sampling and analysis systems

    SciTech Connect

    Beals, D.

    2000-06-08

    A rapid field portable sample and analysis system has been demonstrated at the Savannah River Site and the Hanford Site. The portable system can be used when rapid decisions are needed in the field during scoping or remediation activities, or when it is impractical to bring large volumes of water to the lab for analysis.

  5. Approximate quasi-isodynamicity at a finite aspect ratio in a stellarator vacuum magnetic field

    SciTech Connect

    Mikhailov, M. I.; Nührenberg, J. Zille, R.

    2015-12-15

    A stellarator vacuum field is found in which, at a finite aspect ratio (A ≈ 40), the contours of the second adiabatic invariant of nearly all particles reflected inside that surface are poloidally closed.

  6. An Automated Field Bakery System for Bread

    DTIC Science & Technology

    1983-10-01

    the bakery demonstrated to be able to make, proof and bake bread dough , continuously, at a rate of approximately 850 lbs of dough per hour. I Depanning...with continuous dough -making machinery, a total bread -making process of about one hour was demonstrated. It became clear that a continuous baking system...E), and divider/panner (F). 5 Artist concept of continuous proofer (A) and bake oven (B). Bread 17 from the dough maker enters proofer at the left. 6

  7. Topological field theory of dynamical systems

    SciTech Connect

    Ovchinnikov, Igor V.

    2012-09-15

    Here, it is shown that the path-integral representation of any stochastic or deterministic continuous-time dynamical model is a cohomological or Witten-type topological field theory, i.e., a model with global topological supersymmetry (Q-symmetry). As many other supersymmetries, Q-symmetry must be perturbatively stable due to what is generically known as non-renormalization theorems. As a result, all (equilibrium) dynamical models are divided into three major categories: Markovian models with unbroken Q-symmetry, chaotic models with Q-symmetry spontaneously broken on the mean-field level by, e.g., fractal invariant sets (e.g., strange attractors), and intermittent or self-organized critical (SOC) models with Q-symmetry dynamically broken by the condensation of instanton-antiinstanton configurations (earthquakes, avalanches, etc.) SOC is a full-dimensional phase separating chaos and Markovian dynamics. In the deterministic limit, however, antiinstantons disappear and SOC collapses into the 'edge of chaos.' Goldstone theorem stands behind spatio-temporal self-similarity of Q-broken phases known under such names as algebraic statistics of avalanches, 1/f noise, sensitivity to initial conditions, etc. Other fundamental differences of Q-broken phases is that they can be effectively viewed as quantum dynamics and that they must also have time-reversal symmetry spontaneously broken. Q-symmetry breaking in non-equilibrium situations (quenches, Barkhausen effect, etc.) is also briefly discussed.

  8. Topological field theory of dynamical systems.

    PubMed

    Ovchinnikov, Igor V

    2012-09-01

    Here, it is shown that the path-integral representation of any stochastic or deterministic continuous-time dynamical model is a cohomological or Witten-type topological field theory, i.e., a model with global topological supersymmetry (Q-symmetry). As many other supersymmetries, Q-symmetry must be perturbatively stable due to what is generically known as non-renormalization theorems. As a result, all (equilibrium) dynamical models are divided into three major categories: Markovian models with unbroken Q-symmetry, chaotic models with Q-symmetry spontaneously broken on the mean-field level by, e.g., fractal invariant sets (e.g., strange attractors), and intermittent or self-organized critical (SOC) models with Q-symmetry dynamically broken by the condensation of instanton-antiinstanton configurations (earthquakes, avalanches, etc.) SOC is a full-dimensional phase separating chaos and Markovian dynamics. In the deterministic limit, however, antiinstantons disappear and SOC collapses into the "edge of chaos." Goldstone theorem stands behind spatio-temporal self-similarity of Q-broken phases known under such names as algebraic statistics of avalanches, 1/f noise, sensitivity to initial conditions, etc. Other fundamental differences of Q-broken phases is that they can be effectively viewed as quantum dynamics and that they must also have time-reversal symmetry spontaneously broken. Q-symmetry breaking in non-equilibrium situations (quenches, Barkhausen effect, etc.) is also briefly discussed.

  9. Topological field theory of dynamical systems

    NASA Astrophysics Data System (ADS)

    Ovchinnikov, Igor V.

    2012-09-01

    Here, it is shown that the path-integral representation of any stochastic or deterministic continuous-time dynamical model is a cohomological or Witten-type topological field theory, i.e., a model with global topological supersymmetry (Q-symmetry). As many other supersymmetries, Q-symmetry must be perturbatively stable due to what is generically known as non-renormalization theorems. As a result, all (equilibrium) dynamical models are divided into three major categories: Markovian models with unbroken Q-symmetry, chaotic models with Q-symmetry spontaneously broken on the mean-field level by, e.g., fractal invariant sets (e.g., strange attractors), and intermittent or self-organized critical (SOC) models with Q-symmetry dynamically broken by the condensation of instanton-antiinstanton configurations (earthquakes, avalanches, etc.) SOC is a full-dimensional phase separating chaos and Markovian dynamics. In the deterministic limit, however, antiinstantons disappear and SOC collapses into the "edge of chaos." Goldstone theorem stands behind spatio-temporal self-similarity of Q-broken phases known under such names as algebraic statistics of avalanches, 1/f noise, sensitivity to initial conditions, etc. Other fundamental differences of Q-broken phases is that they can be effectively viewed as quantum dynamics and that they must also have time-reversal symmetry spontaneously broken. Q-symmetry breaking in non-equilibrium situations (quenches, Barkhausen effect, etc.) is also briefly discussed.

  10. Distributed magnetic field positioning system using code division multiple access

    NASA Technical Reports Server (NTRS)

    Prigge, Eric A. (Inventor)

    2003-01-01

    An apparatus and methods for a magnetic field positioning system use a fundamentally different, and advantageous, signal structure and multiple access method, known as Code Division Multiple Access (CDMA). This signal architecture, when combined with processing methods, leads to advantages over the existing technologies, especially when applied to a system with a large number of magnetic field generators (beacons). Beacons at known positions generate coded magnetic fields, and a magnetic sensor measures a sum field and decomposes it into component fields to determine the sensor position and orientation. The apparatus and methods can have a large `building-sized` coverage area. The system allows for numerous beacons to be distributed throughout an area at a number of different locations. A method to estimate position and attitude, with no prior knowledge, uses dipole fields produced by these beacons in different locations.

  11. Field testing of asphalt-emulsion radon-barrier system

    SciTech Connect

    Hartley, J.N.; Freeman, H.D.; Baker, E.G.; Elmore, M.R.; Nelson, D.A.; Voss, C.F.; Koehmstedt, P.L.

    1981-09-01

    Three years of laboratory and field testing have demonstrated that asphalt emulsion seals are effective radon diffusion barriers. Both laboratory and field tests in 1979, 1980 and 1981 have shown that an asphalt emulsion seal can reduce radon fluxes by greater than 99.9%. The effective diffusion coefficient for the various asphalt emulsion admix seals averages about 10/sup -6/ cm/sup 2//s. The 1981 joint field test is a culmination of all the technology developed to date for asphalt emulsion radon barrier systems. Preliminary results of this field test and the results of the 1980 field test are presented. 18 figures, 6 tables.

  12. Field Testing of a Portable Radiation Detector and Mapping System

    SciTech Connect

    Hofstetter, K.J.; Hayes, D.W.; Eakle, R.F.

    1998-03-01

    Researchers at the Savannah River Site (SRS) have developed a man- portable radiation detector and mapping system (RADMAPS) which integrates the accumulation of radiation information with precise ground locations. RADMAPS provides field personnel with the ability to detect, locate, and characterize nuclear material at a site or facility by analyzing the gamma or neutron spectra and correlating them with position. the man-portable field unit records gamma or neutron count rate information and its location, along with date and time, using an embedded Global Positioning System (GPS). RADMAPS is an advancement in data fusion, integrating several off-the-shelf technologies with new computer software resulting in a system that is simple to deploy and provides information useful to field personnel in an easily understandable form. Decisions on subsequent actions can be made in the field to efficiently use available field resources. The technologies employed in this system include: recording GPS, radiation detection (typically scintillation detectors), pulse height analysis, analog-to-digital converters, removable solid-state (Flash or SRAM) memory cards, Geographic Information System (GIS) software and personal computers with CD-ROM supporting digital base maps. RADMAPS includes several field deployable data acquisition systems designed to simultaneously record radiation and geographic positions. This paper summarizes the capabilities of RADMAPS and some of the results of field tests performed with the system.

  13. Field Calibration Procedures for Multibeam Sonar Systems

    DTIC Science & Technology

    1998-06-01

    include multibeam sonar transducers, light detection and ranging ( LIDAR ) surveys, acoustic seafloor classification systems, sub-bottom profilers, and... DTM ) of the reference surface is created from the cleaned data, and an averaging gridding algorithm is used to smooth the data. The gridding size...should be no larger than the average footprint of the inner beams. Using large vertical exaggeration, the DTM should be observed on 3-D visualization

  14. Motion of a charged particle in a nearly axisymmetric magnetic field

    SciTech Connect

    Weitzner, H

    1980-11-01

    The motion of a charged particle in a static magnetic field is studied by means of repeated canonical transformations of a Hamiltonian system. Adiabatic invariants are generated based on the assumption that the particle larmor radius is small compared with the characteristic distance over which the magnetic field varies. Unlike many earlier treatments the transformations presented here preserve the axisymmetry of the dynamics when the magnetic field is axisymmetric. It is assumed that the magnetic field consists of a small nonaxisymmetric part plus the axisymmetric toroidal and poloidal parts. After the introduction of the magnetic moment adiabatic invariant the motion of the guiding center is studied. The results depend sensitively on the ratio of the poloidal magnetic field to the total magnetic field. In some cases a second adiabatic invariant exists and direct inferences concerning long time particle drifts are possible. In one case where a second adiabatic invariant fails to exist, long term drifts are studied by conventional perturbation expansions. At some points resonance or lack of resonance phenomena appear and determine the drift effects.

  15. Filmless Radiographic System for Field Use.

    DTIC Science & Technology

    1988-02-12

    Capacitor Charging Circuit The capacitor charging circuit (Fig. 5) maintains the required voltage level on the energy storage capacitors. The circuit is...capacitor voltage reaches the required level (approximately 300V) the charging circuit shuts down and the entire system idles with a current drain of only 80...external monitoring of the mA and kV levels during an exposure. The mA circuit consists of a mini-plug, which provides access to the MA signal from the

  16. Small animal electric and magnetic field exposure systems. Final report

    SciTech Connect

    Patterson, R.C.; Dietrich, F.M.

    1993-10-01

    Laboratory evaluation of electric and magnetic fields (EMF) and cancer in animals requires exposure of relatively large numbers of animals, usually rats or mice, to 60-Hz fields under very well controlled conditions for periods of up to two years. This report describes two exposure systems, the first of which is based on modifications of an existing electric field exposure system to include magnetic field exposure capability. In this system, each module houses 576--768 mice, which can be exposed to electric field levels of up to 100 kV/m and magnetic field levels of up to 10 Gauss. When a module was operated at 10 Gauss, measured levels of noise and vibration fell substantially below the detection threshold for humans. Moreover, temperature rise in the coils did not exceed 12{degrees}C at the 10 Gauss level. Specifications and test results for the second system, which provides magnetic field exposure capability only, are similar, except that each module houses 624--780 mice. After installation of the second system at the West Los Angeles Veterans Medical Center in Los Angeles, California, additional results were obtained. This report provides a complete description of the engineering design, specifications, and test results for the completed systems.

  17. Extrapolation of the DIII-D high poloidal beta scenario to ITER steady-state using transport modeling

    NASA Astrophysics Data System (ADS)

    McClenaghan, J.; Garofalo, A. M.; Meneghini, O.; Smith, S. P.

    2016-10-01

    Transport modeling of a proposed ITER steady-state scenario based on DIII-D high βP discharges finds that the core confinement may be improved with either sufficient rotation or a negative central shear q-profile. The high poloidal beta scenario is characterized by a large bootstrap current fraction( 80%) which reduces the demands on the external current drive, and a large radius internal transport barrier which is associated with improved normalized confinement. Typical temperature and density profiles from the non-inductive high poloidal beta scenario on DIII-D are scaled according to 0D modeling predictions of the requirements for achieving Q=5 steady state performance in ITER with ``day one'' H&CD capabilities. Then, TGLF turbulence modeling is carried out under systematic variations of the toroidal rotation and the core q-profile. Either strong negative central magnetic shear or rotation are found to successfully provide the turbulence suppression required to maintain the temperature and density profiles. This work supported by the US Department of Energy under DE-FC02-04ER54698.

  18. Reactions of the nervous system to magnetic fields

    NASA Technical Reports Server (NTRS)

    Kholodov, Y. A.

    1974-01-01

    This magnetobiological survey considers sensory, nervous, stress and genetic effects of magnetic fields on man and animals. It is shown that the nervous system plays an important role in the reactions of the organism to magnetic fields; the final biological effect is a function of the strength of the magnetic fields, the gradient, direction of the lines of force, duration and location of the action, and the functional status of the organism.

  19. The Center-TRACON Automation System: Simulation and field testing

    NASA Technical Reports Server (NTRS)

    Denery, Dallas G.; Erzberger, Heinz

    1995-01-01

    A new concept for air traffic management in the terminal area, implemented as the Center-TRACON Automation System, has been under development at NASA Ames in a cooperative program with the FAA since 1991. The development has been strongly influenced by concurrent simulation and field site evaluations. The role of simulation and field activities in the development process will be discussed. Results of recent simulation and field tests will be presented.

  20. Magnetic fields of the solar system: A comparative planetology toolkit

    NASA Astrophysics Data System (ADS)

    Nicholas, J. B.; Purucker, M. E.; Johnson, C. L.; Sabaka, T. J.; Olsen, N.; Sun, Z.; Al Asad, M.; Anderson, B. J.; Korth, H.; Slavin, J. A.; Alexeev, I. I.; Belenkaya, E. S.; Phillips, R. J.; Solomon, S. C.; Lillis, R. J.; Langlais, B.; Winslow, R. M.; Russell, C. T.; Dougherty, M. K.; Zuber, M. T.

    2011-12-01

    Magnetic fields within the solar system provide a strong organizing force for processes active both within a planet or moon, and outside of it. In the interest of stimulating research and education in the field of comparative planetology, we present documented Fortran and MATLAB source codes and benchmarks to the latest models for planets and satellites that host internal magnetic fields. This presentation is made in the context of an interactive website: http://planetary-mag.net. Models are included for Earth (Comprehensive model CM4 of Sabaka et al., 2004, Geophysics J. Int.), Mercury (Anderson et al, 2011, Science), the Moon (Purucker and Nicholas, 2010, JGR), Mars (Lillis et al., 2010, JGR), and the outer planets Jupiter, Saturn, Uranus, and Neptune (Russell and Dougherty, 2010, Space Science Reviews). All models include magnetic fields of internal origin, and fields of external origin are included in the models for Mercury, the Earth, and the Moon. As models evolve, we intend to include magnetic fields of external origin for the other planets and moons. The website allows the user to select a coordinate system, such as planet-centered, heliocentric, or boundary normal, and the location within that coordinate system, and the vector magnetic field due to each of the component source fields at that location is then calculated and presented. Alternatively, the user can input a range as well as a grid spacing, and the vector magnetic field will be calculated for all points on that grid and be made available as a file for downloading.

  1. CALIPERS. Planning the Systems Approach to Field Testing Educational Products.

    ERIC Educational Resources Information Center

    Southwest Educational Development Lab., Austin, TX.

    Field testing, the last step in the developmental cycle for educational products, must ascertain whether the test product, placed in a natural environment, will actually elicit the behavioral changes it was designed to effect. A systems approach to field testing requires that certain basic areas of investigation first be established. Specific…

  2. Magnetic field in the Lobachevsky space and related integrable systems

    SciTech Connect

    Kurochkin, Yu. A. Otchik, V. S.; Ovsiyuk, E. M.

    2012-10-15

    Various possibilities to define analogs of the uniform magnetic field in the Lobachevsky space are considered using different coordinate systems in this space. Quantum mechanical problem of motion in the defined fields is also treated. Variables in the Schroedinger equation are separated and diagonal operators are found. For some cases, exact solutions are obtained.

  3. Field trial of rural solar photovoltaic system

    NASA Astrophysics Data System (ADS)

    Basu, P.; Mukhopadhyay, K.; Banerjee, T.; Das, S.; Saha, H.

    Experience, costs, and performance of photovoltaic (PV) systems set up in a remote Indian village to power an adult literacy center and an irrigation pump are described. The center was furnished with a 14-module, 200 W array to power a television and three fluorescent lamps. The pumping installation has 20 modules for a 300 W output directly coupled to a 300-W dc pump motor. Data were gathered on the open circuit voltage, short circuit current, specific gravity of the battery fluid, degradation of the cells, nominal operating temperature of the cells, load currents, Amp-hours, water flow rate (pump), and the static head and draw down rate (pump). Monitoring of the array performances in the dusty environment showed that once/week cleaning is necessary. Al-substrates cracked at the center installation and sealant evaporation caused condensation which degraded the light transmissivity and thereby the short-circuit current of the modules. The combination of low-efficiency (5 pct) cells and cheap labor demonstrated economic operation without high-efficiency cells.

  4. Entropy squeezing for qubit – field system under decoherence effect

    SciTech Connect

    Abdel-Khalek, S; Berrada, K; A-S F Obada; Wahiddin, M R

    2014-03-28

    We study in detail the dynamics of field entropy squeezing (FES) for a qubit – field system whose dynamics is described by the phase-damped model. The results of calculations show that the initial state and decoherence play a crucial role in the evolution of FES. During the temporal evolution of the system under decoherence effect, an interesting monotonic relation between FES, Wehrl entropy (WE) and negativity is observed. (laser applications and other topics in quantum electronics)

  5. Field theories and exact stochastic equations for interacting particle systems

    SciTech Connect

    Andreanov, Alexei; Lefevre, Alexandre; Biroli, Giulio; Bouchaud, Jean-Philippe

    2006-09-15

    We consider the dynamics of interacting particles with reaction and diffusion. Starting from the underlying discrete stochastic jump process we derive a general field theory describing the dynamics of the density field, which we relate to an exact stochastic equation on the density field. We show how our field theory maps onto the original Doi-Peliti formalism, allowing us to clarify further the issue of the 'imaginary' Langevin noise that appears in the context of reaction-diffusion processes. Our procedure applies to a wide class of problems and is related to large deviation functional techniques developed recently to describe fluctuations of nonequilibrium systems in the hydrodynamic limit.

  6. Conceptual models of the evolution of transgressive dune field systems

    NASA Astrophysics Data System (ADS)

    Hesp, Patrick A.

    2013-10-01

    This paper examines the evolutionary paths of some transgressive dune fields that have formed on different coasts of the world, and presents some initial conceptual models of system dynamics for transgressive dune sheets and dune fields. Various evolutionary pathways are conceptualized based on a visual examination of dune fields from around the world. On coasts with high sediment supply, dune sheets and dune fields tend to accumulate as large scale barrier systems with little colonization of vegetation in arid-hyper to arid climate regimes, and as multiple, active discrete phases of dune field and deflation plain couplets in temperate to tropical environments. Active dune fields tend to be singular entities on coasts with low to moderate sediment supply. Landscape complexity and vegetation richness and diversity increases as dune fields evolve from simple active sheets and dunes to single and multiple deflation plains and basins, precipitation ridges, nebkha fields and a host of other dune types associated with vegetation (e.g. trailing ridges, slacks, remnant knobs, gegenwalle ridges and dune track ridges, 'tree islands' and 'bush pockets'). Three principal scenarios of transgressive dune sheet and dune field development are discussed, including dune sheets or dune fields evolving directly from the backshore, development following foredune and/or dune field erosion, and development from the breakdown or merging of parabolic dunes. Various stages of evolution are outlined for each scenario. Knowledge of evolutionary patterns and stages in coastal dune fields is very limited and caution is urged in attempts to reverse, change and/or modify dune fields to 'restore' some perceived loss of ecosystem or dune functioning.

  7. Conceptual models of the evolution of transgressive dune field systems

    NASA Astrophysics Data System (ADS)

    A. Hesp, Patrick

    2013-10-01

    This paper examines the evolutionary paths of some transgressive dune fields that have formed on different coasts of the world, and presents some initial conceptual models of system dynamics for transgressive dune sheets and dune fields. Various evolutionary pathways are conceptualized based on a visual examination of dune fields from around the world. On coasts with high sediment supply, dune sheets and dune fields tend to accumulate as large scale barrier systems with little colonization of vegetation in arid-hyper to arid climate regimes, and as multiple, active discrete phases of dune field and deflation plain couplets in temperate to tropical environments. Active dune fields tend to be singular entities on coasts with low to moderate sediment supply. Landscape complexity and vegetation richness and diversity increases as dune fields evolve from simple active sheets and dunes to single and multiple deflation plains and basins, precipitation ridges, nebkha fields and a host of other dune types associated with vegetation (e.g. trailing ridges, slacks, remnant knobs, gegenwalle ridges and dune track ridges, ‘tree islands' and ‘bush pockets'). Three principal scenarios of transgressive dune sheet and dune field development are discussed, including dune sheets or dune fields evolving directly from the backshore, development following foredune and/or dune field erosion, and development from the breakdown or merging of parabolic dunes. Various stages of evolution are outlined for each scenario. Knowledge of evolutionary patterns and stages in coastal dune fields is very limited and caution is urged in attempts to reverse, change and/or modify dune fields to ‘restore' some perceived loss of ecosystem or dune functioning.

  8. NASA-JSC antenna near-field measurement system

    NASA Technical Reports Server (NTRS)

    Cooke, W. P.; Friederich, P. G.; Jenkins, B. M.; Jameson, C. R.; Estrada, J. P.

    1988-01-01

    Work was completed on the near-field range control software. The capabilities of the data processing software were expanded with the addition of probe compensation. In addition, the user can process the measured data from the same computer terminal used for range control. The design of the laser metrology system was completed. It provides precise measruement of probe location during near-field measurements as well as position data for control of the translation beam and probe cart. A near-field range measurement system was designed, fabricated, and tested.

  9. [A focused sound field measurement system by LabVIEW].

    PubMed

    Jiang, Zhan; Bai, Jingfeng; Yu, Ying

    2014-05-01

    In this paper, according to the requirement of the focused sound field measurement, a focused sound field measurement system was established based on the LabVIEW virtual instrument platform. The system can automatically search the focus position of the sound field, and adjust the scanning path according to the size of the focal region. Three-dimensional sound field scanning time reduced from 888 hours in uniform step to 9.25 hours in variable step. The efficiency of the focused sound field measurement was improved. There is a certain deviation between measurement results and theoretical calculation results. Focal plane--6 dB width difference rate was 3.691%, the beam axis--6 dB length differences rate was 12.937%.

  10. Magnetic field effects in electron systems with imperfect nesting

    NASA Astrophysics Data System (ADS)

    Sboychakov, A. O.; Rakhmanov, A. L.; Kugel, K. I.; Rozhkov, A. V.; Nori, Franco

    2017-01-01

    We analyze the effects of an applied magnetic field on the phase diagram of a weakly correlated electron system with imperfect nesting. The Hamiltonian under study describes two bands: electron and hole ones. Both bands have spherical Fermi surfaces, whose radii are slightly mismatched due to doping. These types of models are often used in the analysis of magnetic states in chromium and its alloys, superconducting iron pnictides, AA-type bilayer graphene, borides, etc. At zero magnetic field, the uniform ground state of the system turns out to be unstable against electronic phase separation. The applied magnetic field affects the phase diagram in several ways. In particular, the Zeeman term stabilizes new antiferromagnetic phases. It also significantly shifts the boundaries of inhomogeneous (phase-separated) states. At sufficiently high fields, the Landau quantization gives rise to oscillations of the order parameters and of the Néel temperature as a function of the magnetic field.

  11. Long wavelength infrared dual field-of-view optical system

    NASA Astrophysics Data System (ADS)

    Xiong, Tao; Yang, Chang-cheng

    2007-12-01

    For cooled 320×240 staring focal plane array (FPA), a novel long wavelength infrared dual field-of-view optical system is presented in the paper. The optical system is composed of re-imaging part and zooming part. The parameters of the system are 1.96 f/number, 100% cold shield efficiency, 180mm/60mm effective focal length (EFL) and 8-10 μm spectrum region. The optical system is analyzed from two modes of narrow field of view (NFOV) and wide field of view (WFOV). The system can be used in the temperature range from-30°Cand 60°C without significant degradation of optical performance. The final test results prove the designed performance is good..

  12. Control and data acquisition systems for high field superconducting wigglers

    NASA Astrophysics Data System (ADS)

    Batrakov, A.; Ilyin, I.; Karpov, G.; Kozak, V.; Kuzin, M.; Kuper, E.; Mamkin, V.; Mezentsev, N.; Repkov, V.; Selivanov, A.; Shkaruba, V.

    2001-07-01

    This paper describes the control and DAQ system of superconducting wigglers with magnetic field range up to 10.3 T. The first version of the system controls a 7 T superconducting wiggler prepared for installation at Bessy-II (Germany). The second one controls a 10 T wiggler which is under testing now at the SPring-8 site (Japan). Both systems are based on VME apparatus. The set of specialized VME modules is elaborated to arrange wiggler power supply control, full time wiggler monitoring, and magnetic field high accuracy measurement and field stabilization. The software for the control of the wigglers is written in C language for VxWorks operation system for a Motorola-162 VME controller. The task initialization, stops and acquisition of the data can be done from the nearest personal computer (FTP host for VME), or from the remote system as well.

  13. Electromagnetic Propulsion System for Spacecraft using Geomagnetic fields and Superconductors

    NASA Astrophysics Data System (ADS)

    Dadhich, Anang

    This thesis concentrates on developing an innovative method to generate thrust force for spacecraft in localized geomagnetic fields by various electromagnetic systems. The proposed electromagnetic propulsion system is an electromagnet, like normal or superconducting solenoid, having its own magnetic field which interacts with the planet's magnetic field to produce a reaction thrust force. The practicality of the system is checked by performing simulations in order the find the varying radius, velocity, and acceleration changes. The advantages, challenges, various optimization techniques, and viability of such a propulsion system in present day and future are discussed. The propulsion system such developed is comparable to modern MPD Thrusters and electric engines, and has various applications like spacecraft propulsion, orbit transfer and stationkeeping.

  14. An artificial compound eye system for large field imaging

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Shi, Lifang; Shi, Ruiying; Dong, Xiaochun; Deng, Qiling; Du, Chunlei

    2012-11-01

    With the rapid development of science and technology, optical imaging system has been widely used, and the performance requirements are getting higher and higher such as lighter weight, smaller size, larger field of view and more sensitive to the moving targets. With the advantages of large field of view, high agility and multi-channels, compound eye is more and more concerned by academia and industry. In this work, an artificial spherical compound eye imaging system is proposed, which is formed by several mini cameras to get a large field of view. By analyzing the relationship of the view field between every single camera and the whole system, the geometric arrangement of cameras is studied and the compound eye structure is designed. By using the precision machining technology, the system can be manufactured. To verify the performance of this system, experiments were carried out, where the compound eye was formed by seven mini cameras which were placed centripetally along a spherical surface so that each camera points in a different direction. Pictures taken by these cameras were mosaiced into a complete image with large field of view. The results of the experiments prove the validity of the design method and the fabrication technology. By increasing the number of the cameras, larger view field even panoramic imaging can be realized by using this artificial compound eye.

  15. Dynamic formation of a hot field reversed configuration with improved confinement by supersonic merging of two colliding high-β compact toroids.

    PubMed

    Binderbauer, M W; Guo, H Y; Tuszewski, M; Putvinski, S; Sevier, L; Barnes, D; Rostoker, N; Anderson, M G; Andow, R; Bonelli, L; Brandi, F; Brown, R; Bui, D Q; Bystritskii, V; Ceccherini, F; Clary, R; Cheung, A H; Conroy, K D; Deng, B H; Dettrick, S A; Douglass, J D; Feng, P; Galeotti, L; Garate, E; Giammanco, F; Glass, F J; Gornostaeva, O; Gota, H; Gupta, D; Gupta, S; Kinley, J S; Knapp, K; Korepanov, S; Hollins, M; Isakov, I; Jose, V A; Li, X L; Luo, Y; Marsili, P; Mendoza, R; Meekins, M; Mok, Y; Necas, A; Paganini, E; Pegoraro, F; Pousa-Hijos, R; Primavera, S; Ruskov, E; Qerushi, A; Schmitz, L; Schroeder, J H; Sibley, A; Smirnov, A; Song, Y; Sun, X; Thompson, M C; Van Drie, A D; Walters, J K; Wyman, M D

    2010-07-23

    A hot stable field-reversed configuration (FRC) has been produced in the C-2 experiment by colliding and merging two high-β plasmoids preformed by the dynamic version of field-reversed θ-pinch technology. The merging process exhibits the highest poloidal flux amplification obtained in a magnetic confinement system (over tenfold increase). Most of the kinetic energy is converted into thermal energy with total temperature (T{i}+T{e}) exceeding 0.5 keV. The final FRC state exhibits a record FRC lifetime with flux confinement approaching classical values. These findings should have significant implications for fusion research and the physics of magnetic reconnection.

  16. Upgrades of poloidal and tangential x-ray imaging crystal spectrometers for temperature and rotation measurements on EAST

    NASA Astrophysics Data System (ADS)

    Wang, Fudi; Chen, Jun; Hu, Ruiji; Lyu, Bo; Colledani, Gilles; Fu, Jia; Li, Yingying; Bitter, Manfred; Hill, Kenneth; Lee, Sangon; Ye, Minyou; Shi, Yuejiang; Wan, Baonian

    2016-11-01

    During the past two years, key parts of poloidal and tangential x-ray imaging crystal spectrometers (PXCSs and TXCSs) have been upgraded. For poloidal XCSs, double-crystals of ArXVII and FeXXV were deployed. For fulfilling in situ alignment of a poloidal XCS, the beryllium window must be flexibly removed. By utilizing a design, where the beryllium window was installed in the vacuum chamber of the double-crystal, and between the double-crystal and wall of this chamber, an in situ alignment for the two spectrometers was fulfilled. Also, a new holder for the double-crystal was installed to allow for precise adjustments of azimuth angle and vertical height of the double-crystal. In order to facilitate these adjustments of double-crystal and installation of beryllium window, the chamber of the double-crystal for PXCS was upgraded from a cylinder to a cuboid. The distance between double-crystal and magnetic axis was extended from 8936 mm to 9850 mm in order to improve spatial resolution for PXCS, which is currently in the range from 1.237 mm to 4.80 mm at magnetic axis. Furthermore, a new pixelated detector (PILATUS 900K), which has a large sensitive area of 83.8 × 325.3 mm2 and which is vacuum compatible, is being implemented on the PXCS. This detector is mounted on a rail, so that its position can be changed by 50 mm to effectively record spectra of He-like argon and He-like iron (ArXVII and FeXXV). Similarly, a rail, which allows detector movement by 50 mm, was also installed in TXCS to alternatively record spectra of ArXVII and ArXVIII. Presently, the operation duration of PXCS and TXCS has been upgraded to hundreds of seconds in one shot. Ti- and uϕ-profiles measured by TXCS and charge exchange recombination spectroscopy (CXRS) were compared and found to be in good agreement.

  17. A Method to Localize RF B1 Field in High-Field Magnetic Resonance Imaging Systems

    PubMed Central

    Yoo, Hyoungsuk; Gopinath, Anand; Vaughan, J. Thomas

    2014-01-01

    In high-field magnetic resonance imaging (MRI) systems, B0 fields of 7 and 9.4 T, the RF field shows greater inhomogeneity compared to clinical MRI systems with B0 fields of 1.5 and 3.0 T. In multichannel RF coils, the magnitude and phase of the input to each coil element can be controlled independently to reduce the nonuniformity of the RF field. The convex optimization technique has been used to obtain the optimum excitation parameters with iterative solutions for homogeneity in a selected region of interest. The pseudoinverse method has also been used to find a solution. The simulation results for 9.4- and 7-T MRI systems are discussed in detail for the head model. Variation of the simulation results in a 9.4-T system with the number of RF coil elements for different positions of the regions of interest in a spherical phantom are also discussed. Experimental results were obtained in a phantom in the 9.4-T system and are compared to the simulation results and the specific absorption rate has been evaluated. PMID:22929360

  18. The Neutron Imaging System Fielded at the National Ignition Facility

    SciTech Connect

    Fittinghoff, D N; Atkinson, D P; Bower, D E; Drury, O B; Dzenitis, J M; Felker, B; Frank, M; Liddick, S N; Moran, M J; Roberson, G P; Weiss, P B; Grim, G P; Aragonez, R J; Archuleta, T N; Batha, S H; Clark, D D; Clark, D J; Danly, C R; Day, R D; Fatherley, V E; Finch, J P; Garcia, F P; Gallegos, R A; Guler, N; Hsu, A H; Jaramillo, S A; Loomis, E N; Mares, D; Martinson, D D; Merrill, F E; Morgan, G L; Munson, C; Murphy, T J; Oertel, J A; Polk, P J; Schmidt, D W; Tregillis, I L; Valdez, A C; Volegov, P L; Wang, T F; Wilde, C H; Wilke, M D; Wilson, D C; Buckles, R A; Cradick, J R; Kaufman, M I; Lutz, S S; Malone, R M; Traille, A

    2011-10-24

    We have fielded a neutron imaging system at the National Ignition Facility to collect images of fusion neutrons produced in the implosion of inertial confinement fusion experiments and scattered neutrons from (n, n') reactions of the source neutrons in the surrounding dense material. A description of the neutron imaging system will be presented, including the pinhole array aperture, the line-of-sight collimation, the scintillator-based detection system and the alignment systems and methods. Discussion of the alignment and resolution of the system will be presented. We will also discuss future improvements to the system hardware.

  19. Stability of toroidal magnetic fields in stellar interiors

    NASA Astrophysics Data System (ADS)

    Ibáñez-Mejía, J. C.; Braithwaite, J.

    2015-06-01

    Aims: Magnetic fields play an important role during the formation and evolution of stars. Of particular interest in stellar evolution is what effect they have on the transport angular momentum and mixing of chemical elements along the radial direction in radiative regions. Current theories suggest a dynamo loop as the mechanism responsible for maintaining the magnetic field in the radiative zone. This loop consists of differential rotation on one side and magnetohydrodynamic (MHD) instability - the so-called Tayler instability - on the other. However, how this might work quantitatively is still an unsettled question, largely because we do not yet understand all the properties of the instability in question. In this paper we explore some properties of the Tayler instability. Methods: We present 3D MHD simulations of purely toroidal and mixed poloidal-toroidal magnetic field configurations to study the behavior of the Tayler instability. For the first time the simultaneous action of rotation and magnetic diffusion are taken into account and the effects of a poloidal field on the dynamic evolution of unstable toroidal magnetic fields is included. Results: In the absence of diffusion, fast rotation (rotation rate, Ω∥, compared to Alfvén frequency, ωA,φ) is able to suppress the instability when the rotation and magnetic axes are aligned and when the radial field strength gradient p< 1.5 (where p ≡ ∂lnB/∂lnϖ and ϖ is the cylindrical radius coordinate). When diffusion is included, this system turns unstable for diffusion dominated and marginally diffusive dominated regions. If the magnetic and rotation axes are perpendicular to each other, Ω⊥, the stabilizing effect induced by the Coriolis force is scale dependent and decreases with increasing wavenumber. In toroidal fields with radial field gradients bigger than p> 1.5, rapid rotation does not suppress the instability but instead introduces a damping factor ωA/ 2Ω∥ to the growth rate, in agreement

  20. PACKAGE PLANTS FOR SMALL SYSTEMS: A FIELD STUDY

    EPA Science Inventory

    A joint field study was conducted by AWWA and the Drinking Water Research Division of USEPA to evaluate existing small community systems that use package plant technology. Forty-eight package plant systems representing a geographic and technological cross section were evaluated t...

  1. Instructional Systems Design: Five Views of the Field.

    ERIC Educational Resources Information Center

    Schiffman, Shirl S.

    1986-01-01

    Discusses difficulties in defining instructional systems design (ISD) and presents five ways the field is viewed, ranging from a narrow view emphasizing media selection to a complete ISD view. The ISD view emphasizes five main components: educational theory and research, system analysis, diffusion, consulting/interpersonal relations, and project…

  2. Double layer field shaping systems for toroidal plasmas

    DOEpatents

    Ohyabu, Nobuyoshi

    1982-01-01

    Methods and apparatus for plasma generation, confinement and control such as Tokamak plasma systems are described having a two layer field shaping coil system comprising an inner coil layer close to the plasma and an outer coil layer to minimize the current in the inner coil layer.

  3. Pulsed field magnetization in rare-earth kagome systems.

    PubMed

    Hoch, M J R; Zhou, H D; Mun, E; Harrison, N

    2016-02-03

    The rare-earth kagome systems R 3Ga5SiO14 (R  =  Nd or Pr) exhibit cooperative paramagnetism at low temperatures. Evidence for correlated spin clusters in these weakly frustrated systems has previously been obtained from neutron scattering and from ESR and NMR results. The present pulsed field (0-60 T, 25 ms) magnetization measurements made on single crystals of Nd3Ga5SiO14 (NGS) and Pr3Ga5SiO14 (PGS) at temperatures down to 450 mK have revealed striking differences in the magnetic responses of the two materials. For NGS the magnetization shows a low field plateau, saturation in high transient fields, and significant hysteresis while the PGS magnetization does not saturate in transient fields up to 60 T and shows no hysteresis or plateaus. Nd(3+) is a Kramers ion while Pr(3+) is a non-Kramers ion and the crystal field effects are quite different in the two systems. For the conditions used in the experiments the magnetization behavior is not in agreement with Heisenberg model predictions for kagome systems in which easy-axis anisotropy is much larger than the exchange coupling. The extremely slow spin dynamics found below 4 K in NGS is, however, consistent with the model for Kramers ions and provides a basis for explaining the pulsed field magnetization features.

  4. An Interactive Web System for Field Data Sharing and Collaboration

    NASA Astrophysics Data System (ADS)

    Weng, Y.; Sun, F.; Grigsby, J. D.

    2010-12-01

    A Web 2.0 system is designed and developed to facilitate data collection for the field studies in the Geological Sciences department at Ball State University. The system provides a student-centered learning platform that enables the users to first upload their collected data in various formats, interact and collaborate dynamically online, and ultimately create a shared digital repository of field experiences. The data types considered for the system and their corresponding format and requirements are listed in the table below. The system has six main functionalities as follows. (1) Only the registered users can access the system with confidential identification and password. (2) Each user can upload/revise/delete data in various formats such as image, audio, video, and text files to the system. (3) Interested users are allowed to co-edit the contents and join the collaboration whiteboard for further discussion. (4) The system integrates with Google, Yahoo, or Flickr to search for similar photos with same tags. (5) Users can search the web system according to the specific key words. (6) Photos with recorded GPS readings can be mashed and mapped to Google Maps/Earth for visualization. Application of the system to geology field trips at Ball State University will be demonstrated to assess the usability of the system.Data Requirements

  5. A Web-Based Information System for Field Data Management

    NASA Astrophysics Data System (ADS)

    Weng, Y. H.; Sun, F. S.

    2014-12-01

    A web-based field data management system has been designed and developed to allow field geologists to store, organize, manage, and share field data online. System requirements were analyzed and clearly defined first regarding what data are to be stored, who the potential users are, and what system functions are needed in order to deliver the right data in the right way to the right user. A 3-tiered architecture was adopted to create this secure, scalable system that consists of a web browser at the front end while a database at the back end and a functional logic server in the middle. Specifically, HTML, CSS, and JavaScript were used to implement the user interface in the front-end tier, the Apache web server runs PHP scripts, and MySQL to server is used for the back-end database. The system accepts various types of field information, including image, audio, video, numeric, and text. It allows users to select data and populate them on either Google Earth or Google Maps for the examination of the spatial relations. It also makes the sharing of field data easy by converting them into XML format that is both human-readable and machine-readable, and thus ready for reuse.

  6. Quantum systems with positions and momenta on a Galois field

    NASA Astrophysics Data System (ADS)

    Vourdas, A.

    2008-03-01

    Quantum systems with positions and momenta in the Galois field GF(pe), are considered. The Heisenberg-Weyl group of displacements and the Sp(2,GF(pe)) group of symplectic transformations, are studied. Frobenius symmetries, are a unique feature of these systems and lead to constants of motion. The engineering of such systems from l spins with j = (p - 1)/2, which are coupled in a particular way, is discussed.

  7. Chaotic behavior of magnetic field lines near simplest current systems

    NASA Astrophysics Data System (ADS)

    Veselovsky, I. S.; Lukashenko, A. T.

    2016-12-01

    In the context of studying the problem of simulation of magnetic fields on the Sun, the structure of the field in the vicinity of two circular current loops with different mutual arrangement in space is considered. When the symmetry in the arrangement is sufficient, a system of magnetic surfaces created by the closed field lines arises. With a reduction in symmetry, isolated closed lines may exist. For the case of two identical current loops coupled perpendicularly, it is shown that the subsystems of these lines may be ordered in space in a complex manner. At large distances, a system of loops is equivalent to a dipole with a high degree of accuracy, while an approximate winding of the lines on the deformed toroids, encircling each of the loops, occurs at small distances. At intermediate distances, there are regions of both ordered and chaotic behavior of field lines. Results were obtained with the use of the numerical simulation method.

  8. Suppression of sound radiation to far field of near-field acoustic communication system using evanescent sound field

    NASA Astrophysics Data System (ADS)

    Fujii, Ayaka; Wakatsuki, Naoto; Mizutani, Koichi

    2016-01-01

    A method of suppressing sound radiation to the far field of a near-field acoustic communication system using an evanescent sound field is proposed. The amplitude of the evanescent sound field generated from an infinite vibrating plate attenuates exponentially with increasing a distance from the surface of the vibrating plate. However, a discontinuity of the sound field exists at the edge of the finite vibrating plate in practice, which broadens the wavenumber spectrum. A sound wave radiates over the evanescent sound field because of broadening of the wavenumber spectrum. Therefore, we calculated the optimum distribution of the particle velocity on the vibrating plate to reduce the broadening of the wavenumber spectrum. We focused on a window function that is utilized in the field of signal analysis for reducing the broadening of the frequency spectrum. The optimization calculation is necessary for the design of window function suitable for suppressing sound radiation and securing a spatial area for data communication. In addition, a wide frequency bandwidth is required to increase the data transmission speed. Therefore, we investigated a suitable method for calculating the sound pressure level at the far field to confirm the variation of the distribution of sound pressure level determined on the basis of the window shape and frequency. The distribution of the sound pressure level at a finite distance was in good agreement with that obtained at an infinite far field under the condition generating the evanescent sound field. Consequently, the window function was optimized by the method used to calculate the distribution of the sound pressure level at an infinite far field using the wavenumber spectrum on the vibrating plate. According to the result of comparing the distributions of the sound pressure level in the cases with and without the window function, it was confirmed that the area whose sound pressure level was reduced from the maximum level to -50 dB was

  9. Field theory and weak Euler-Lagrange equation for classical particle-field systems

    SciTech Connect

    Qin, Hong; Burby, Joshua W; Davidson, Ronald C

    2014-10-01

    It is commonly believed that energy-momentum conservation is the result of space-time symmetry. However, for classical particle-field systems, e.g., Klimontovich-Maxwell and Klimontovich- Poisson systems, such a connection hasn't been formally established. The difficulty is due to the fact that particles and the electromagnetic fields reside on different manifolds. To establish the connection, the standard Euler-Lagrange equation needs to be generalized to a weak form. Using this technique, energy-momentum conservation laws that are difficult to find otherwise can be systematically derived.

  10. Evaluation of sound field systems in elementary school classrooms

    NASA Astrophysics Data System (ADS)

    Vigeant, Michelle C.; Kruger, Kelly

    2003-10-01

    Our primary purpose in this study was to determine the relevant ergonomic issues associated with daily use of sound field systems in elementary school classrooms, in order to develop a purchasing guideline and technical specification. The secondary purpose was to evaluate these systems to identify if one or more acoustical parameters could be used to determine the quality and effectiveness of a system. Six sound field systems, with varying numbers and types of speakers, were chosen as a cross-section of available systems on the market. Six representative classrooms, currently in use, were selected based on a range of reverberation times and background noise levels. All systems were installed for two weeks in each classroom. Student speech intelligibility (SI) tests using phonetically balanced word lists were conducted, as well as teacher interviews. The acoustical parameters measured were clarity ratios C50 and C80, speech transmission indices STI and R(rapid)STI, sound pressure level (SPL) uniformity and frequency response. An improvement in SI was found for all systems. Only SPL uniformity and frequency response were found to be useful distinguishing performance parameters between systems. Ergonomic design aspects of sound field systems had a significant influence on the acceptance and usage in the classroom.

  11. Space vehicle field unit and ground station system

    DOEpatents

    Judd, Stephen; Dallmann, Nicholas; Delapp, Jerry; Proicou, Michael; Seitz, Daniel; Michel, John; Enemark, Donald

    2016-10-25

    A field unit and ground station may use commercial off-the-shelf (COTS) components and share a common architecture, where differences in functionality are governed by software. The field units and ground stations may be easy to deploy, relatively inexpensive, and be relatively easy to operate. A novel file system may be used where datagrams of a file may be stored across multiple drives and/or devices. The datagrams may be received out of order and reassembled at the receiving device.

  12. Role of electrostatic fields in space and astrophysical systems.

    NASA Astrophysics Data System (ADS)

    Lapenta, G.

    2005-12-01

    An unsuspected agent is emerging as a key player in a number of processes relevant to space, solar and astrophysical systems: electrostatic fields. We focus here on two processes that are present both in space and laboratory plasmas. First, we consider the formation and properties of current sheets. Current sheets are key enablers for large scale system evolution: often large scale processes lead to the formation of thin sheets where small scale processes couple with larger scales. Our recent work proposes that small scales instabilities can produce electrostatic fields on large scales with profound effects on the evolution of the system where the sheet is present. In particular, their effect can lead to the onset of reconnection. Second, a recent discovery suggests that electrostatic fields can affect the evolution of confined plasmas in laboratory experiments [2] suggesting that electrostatic fields can be a major player in magnetic dynamo processes. Our work suggests that similar processes can be also at play in space and astrophysical plasmas. We report a number of simulations that put forward a new possibility: that electrostatic fields can be a major player in processes where magnetic field energy is created (dynamo) or destroyed (reconnection). [1] W. Daughton, G. Lapenta, P. Ricci, Phys. Rev. Lett., 93, 105004, 2004 [2] D. Bonfiglio, S. Cappello, D. F. Escande, Phys. Rev. Lett., 94, 145001, 2005

  13. Transport signatures in topological systems coupled to ac fields

    NASA Astrophysics Data System (ADS)

    Ruocco, Leonard; Gómez-León, Álvaro

    2017-02-01

    We study the transport properties of a topological system coupled to an ac electric field by means of Floquet-Keldysh formalism. We consider a semi-infinite chain of dimers coupled to a semi-infinite metallic lead and obtain the density of states and current when the system is out of equilibrium. Our formalism is nonperturbative and allows us to explore, in the thermodynamic limit, a wide range of regimes for the ac field, arbitrary values of the coupling strength to the metallic contact and corrections to the wide-band limit (WBL). We find that hybridization with the contact can change the dimerization phase, and that the current dependence on the field amplitude can be used to discriminate between them. We also show the appearance of side bands and nonequilibrium zero-energy modes, characteristic of the Floquet systems. Our results directly apply to the stability of nonequilibrium topological phases, when transport measurements are used for their detection.

  14. Optimized Operation and Electrical Power Supply System of Ignitor*

    NASA Astrophysics Data System (ADS)

    Coletti, A.; Candela, G.; Coletti, R.; Costa, P.; Maffia, G.; Santinelli, M.; Starace, F.; Sforna, M.; Allegra, G.; Trevisan, L.; Florio, A.; Novaro, R.; Coppi, B.

    2006-10-01

    The performance of the control system for the position and shape of the elongated, tight aspect ratio plasma column of Two reference sets of parameters for the operation of Ignitor have been identified. One, the main set, involves plasma currents up to 11MA and toroidal fields up to 13T. The reduced parameter set corresponds to 7MA with fields of 9T and considerably longer pulse flat-tops. The evolution of the relevant currents in the toroidal and the poloidal field magnet systems has been optimized in order to minimize the requirements on the electrical power supply and cryogenic cooling systems. Thyristor amplifiers are adapted to drive both the toroidal and poloidal field magnet systems. The total installed power for these systems is 2400 MVA. The connection of this to the terminals, involving two nodes of the 400 kV grid, at the Caorso site, which houses a dismantled nuclear power station, has been analyzed and authorized by the TERNA- GRTN Agency. A particular consideration has been given to the problems involving the control of both the position and the shaping of the plasma column.*Sponsored in part by ENEA of Italy and by the U.S. DOE.

  15. Quantum noise in the mirror-field system: A field theoretic approach

    SciTech Connect

    Hsiang, Jen-Tsung; Wu, Tai-Hung; Lee, Da-Shin; King, Sun-Kun; Wu, Chun-Hsien

    2013-02-15

    We revisit the quantum noise problem in the mirror-field system by a field-theoretic approach. Here a perfectly reflecting mirror is illuminated by a single-mode coherent state of the massless scalar field. The associated radiation pressure is described by a surface integral of the stress-tensor of the field. The read-out field is measured by a monopole detector, from which the effective distance between the detector and mirror can be obtained. In the slow-motion limit of the mirror, this field-theoretic approach allows to identify various sources of quantum noise that all in all leads to uncertainty of the read-out measurement. In addition to well-known sources from shot noise and radiation pressure fluctuations, a new source of noise is found from field fluctuations modified by the mirror's displacement. Correlation between different sources of noise can be established in the read-out measurement as the consequence of interference between the incident field and the field reflected off the mirror. In the case of negative correlation, we found that the uncertainty can be lowered than the value predicted by the standard quantum limit. Since the particle-number approach is often used in quantum optics, we compared results obtained by both approaches and examine its validity. We also derive a Langevin equation that describes the stochastic dynamics of the mirror. The underlying fluctuation-dissipation relation is briefly mentioned. Finally we discuss the backreaction induced by the radiation pressure. It will alter the mean displacement of the mirror, but we argue this backreaction can be ignored for a slowly moving mirror. - Highlights: Black-Right-Pointing-Pointer The quantum noise problem in the mirror-field system is re-visited by a field-theoretic approach. Black-Right-Pointing-Pointer Other than the shot noise and radiation pressure noise, we show there are new sources of noise and correlation between them. Black-Right-Pointing-Pointer The noise correlations can

  16. Electromagnetic field strength levels surrounding electronic article surveillance (EAS) systems.

    PubMed

    Harris, C; Boivin, W; Boyd, S; Coletta, J; Kerr, L; Kempa, K; Aronow, S

    2000-01-01

    Electronic article surveillance (EAS) is used in many applications throughout the world to prevent theft. EAS systems produce electromagnetic (EM) energy around exits to create an EM interrogation zone through which protected items must pass before leaving the establishment. Specially designed EAS tags are attached to these items and must either be deactivated or removed prior to passing through the EAS EM interrogation zone to prevent the alarm from sounding. Recent reports in the scientific literature have noted the possibility that EM energy transmitted by EAS systems may interfere with the proper operation of sensitive electronic medical devices. The Food and Drug Administration has the regulatory responsibility to ensure the safety and effectiveness of medical devices. Because of the possibility of electromagnetic interference (EMI) between EAS systems and electronic medical devices, in situ measurements of the electric and magnetic fields were made around various types of EAS systems. Field strength levels were measured around four types of EAS systems: audio frequency magnetic, pulsed magnetic resonant, radio frequency, and microwave. Field strengths from these EAS systems varied with magnetic fields as high as 1073.6 Am(-1) (in close proximity to the audio frequency magnetic EAS system towers), and electric fields up to 23.8 Vm(-1) (in close proximity to the microwave EAS system towers). Medical devices are only required to withstand 3 Vm(-1) by the International Electrotechnical Commission's current medical device standards. The modulation scheme of the signal transmitted by some types of EAS systems (especially the pulsed magnetic resonant) has been shown to be more likely to cause EMI with electronic medical devices. This study complements other work in the field by attaching specific characteristics to EAS transmitted EM energy. The quantitative data could be used to relate medical device EMI with specific field strength levels and signal waveforms

  17. Cryogenetically Cooled Field Effect Transistors for Low-Noise Systems

    NASA Technical Reports Server (NTRS)

    Wollack, Edward J.; Rabin, Douglas M. (Technical Monitor)

    2002-01-01

    Recent tends in the design, fabrication and use of High-Electron-Mobility-Transistors (HEMT) in low noise amplifiers are reviewed. Systems employing these devices have achieved the lowest system noise for wavelengths greater than three millimeters with relatively modest cryogenic cooling requirements in a variety of ground and space based applications. System requirements which arise in employing such devices in imaging applications are contrasted with other leading coherent detector candidates at microwave wavelengths. Fundamental and practical limitations which arise in the context of microwave application of field effect devices at cryogenic temperatures will be discussed from a component and systems point of view.

  18. Airborne water vapor DIAL research: System development and field measurements

    NASA Technical Reports Server (NTRS)

    Higdon, Noah S.; Browell, Edward V.; Ponsardin, Patrick; Chyba, Thomas H.; Grossmann, Benoist E.; Butler, Carolyn F.; Fenn, Marta A.; Mayor, Shane D.; Ismail, Syed; Grant, William B.

    1992-01-01

    This paper describes the airborne differential absorption lidar (DIAL) system developed at the NASA Langley Research Center for remote measurement of water vapor (H2O) and aerosols in the lower atmosphere. The airborne H2O DIAL system was flight tested aboard the NASA Wallops Flight Facility (WFF) Electra aircraft in three separate field deployments between 1989 and 1991. Atmospheric measurements were made under a variety of atmospheric conditions during the flight tests, and several modifications were implemented during this development period to improve system operation. A brief description of the system and major modifications will be presented, and the most significant atmospheric observations will be described.

  19. Electric-field sensors for bullet detection systems

    NASA Astrophysics Data System (ADS)

    Vinci, Stephen; Hull, David; Ghionea, Simon; Ludwig, William; Deligeorges, Socrates; Gudmundsson, Thorkell; Noras, Maciej

    2014-06-01

    Research and experimental trials have shown that electric-field (E-field) sensors are effective at detecting charged projectiles. E-field sensors can likely complement traditional acoustic sensors, and help provide a more robust and effective solution for bullet detection and tracking. By far, the acoustic sensor is the most prevalent technology in use today for hostile fire defeat systems due to compact size and low cost, yet they come with a number of challenges that include multipath, reverberant environments, false positives and low signal-to-noise. Studies have shown that these systems can benefit from additional sensor modalities such as E-field sensors. However, E-field sensors are a newer technology that is relatively untested beyond basic experimental trials; this technology has not been deployed in any fielded systems. The U.S. Army Research Laboratory (ARL) has conducted live-fire experiments at Aberdeen Proving Grounds (APG) to collect data from E-field sensors. Three types of E-field sensors were included in these experiments: (a) an electric potential gradiometer manufactured by Quasar Federal Systems (QFS), (b) electric charge induction, or "D-dot" sensors designed and built by the Army Research Lab (ARL), and (c) a varactor based E-field sensor prototype designed by University of North Carolina-Charlotte (UNCC). Sensors were placed in strategic locations near the bullet trajectories, and their data were recorded. We analyzed the performance of each E-field sensor type in regard to small-arms bullet detection capability. The most recent experiment in October 2013 allowed demonstration of improved versions of the varactor and D-dot sensor types. Results of new real-time analysis hardware employing detection algorithms were also tested. The algorithms were used to process the raw data streams to determine when bullet detections occurred. Performance among the sensor types and algorithm effectiveness were compared to estimates from acoustics signatures

  20. Magnetic field effects in flavoproteins and related systems

    PubMed Central

    Evans, Emrys W.; Dodson, Charlotte A.; Maeda, Kiminori; Biskup, Till; Wedge, C. J.; Timmel, Christiane R.

    2013-01-01

    Within the framework of the radical pair mechanism, magnetic fields may alter the rate and yields of chemical reactions involving spin-correlated radical pairs as intermediates. Such effects have been studied in detail in a variety of chemical systems both experimentally and theoretically. In recent years, there has been growing interest in whether such magnetic field effects (MFEs) also occur in biological systems, a question driven most notably by the increasing body of evidence for the involvement of such effects in the magnetic compass sense of animals. The blue-light photoreceptor cryptochrome is placed at the centre of this debate and photoexcitation of its bound flavin cofactor has indeed been shown to result in the formation of radical pairs. Here, we review studies of MFEs on free flavins in model systems as well as in blue-light photoreceptor proteins and discuss the properties that are crucial in determining the magnetosensitivity of these systems. PMID:24511388

  1. Field Artillery Ammunition Processing System (FAAPS) concept evaluation study

    SciTech Connect

    Kring, C.T.; Babcock, S.M.; Watkin, D.C.; Oliver, R.P.

    1992-06-01

    The Field Artillery Ammunition Processing System (FAAPS) is an initiative to introduce a palletized load system (PLS) that is transportable with an automated ammunition processing and storage system for use on the battlefield. System proponents have targeted a 20% increase in the ammunition processing rate over the current operation while simultaneously reducing the total number of assigned field artillery battalion personnel by 30. The overall objective of the FAAPS Project is the development and demonstration of an improved process to accomplish these goals. The initial phase of the FAAPS Project and the subject of this study is the FAAPS concept evaluation. The concept evaluation consists of (1) identifying assumptions and requirements, (2) documenting the process flow, (3) identifying and evaluating technologies available to accomplish the necessary ammunition processing and storage operations, and (4) presenting alternative concepts with associated costs, processing rates, and manpower requirements for accomplishing the operation. This study provides insight into the achievability of the desired objectives.

  2. Capabilities and limitations of atmospheric transmission field measurement systems

    NASA Astrophysics Data System (ADS)

    Zweibaum, F. M.; Lucia, L. V.; Lamontagne, J. J.; Kozlowski, A. T.

    1981-01-01

    The major subject of the paper is advancing atmospheric transmission field measurement systems in response to new requirements. From the viewpoint of a complete field system installation, attention is given to the nature of the measurement and the capabilities and limitations in sensitivity, stability, and the time required for individual measurements. From the same system viewpoint calibration is reviewed with regard to concept, techniques, uncertainties and assumptions. Examples are given of system advances and these include making real-time measurements with automatic high-speed scanning, high sensitivity, wide spectral range and remote control. Special measurement conditions that are described include those encountered on the battlefield, in fog and precipitation, and in the presence of countermeasures.

  3. Floating production systems hit stride in North Sea fields

    SciTech Connect

    Knott, D.

    1994-05-23

    Floating production system (FPS) technology has come of age in the North Sea. That's apparent in plans to use FPSs to tap two of Northwest Europe's largest offshore oil discoveries in the last 10 years. First North Sea oil production with a floater involved a converted semisubmersible drilling rig. Floaters have been in use for small field development projects ever since. Now, industry's rising interest in FPSs reflects two trends: As the North Sea matures, discoveries are likely to be in deeper, more remote locations; and Operators increasingly are under pressure to slash costs. The paper discusses UK trends, Norway's needs, the Norne field, Norne contract, discovery of oil west of the Shetland Islands, Shell-Esso plans, the UK Machar field test, the UK Fife field, and prospects for other potential floater developments.

  4. Effects of an electric field on interaction of aromatic systems.

    PubMed

    Youn, Il Seung; Cho, Woo Jong; Kim, Kwang S

    2016-04-30

    The effect of uniform external electric field on the interactions between small aromatic compounds and an argon atom is investigated using post-HF (MP2, SCS-MP2, and CCSD(T)) and density functional (PBE0-D3, PBE0-TS, and vdW-DF2) methods. The electric field effect is quantified by the difference of interaction energy calculated in the presence and absence of the electric field. All the post-HF methods describe electric field effects accurately although the interaction energy itself is overestimated by MP2. The electric field effect is explained by classical electrostatic models, where the permanent dipole moment from mutual polarization mainly determines its sign. The size of π-conjugated system does not have significant effect on the electric field dependence. We found out that PBE0-based methods give reasonable interaction energies and electric field response in every case, while vdW-DF2 sometimes shows spurious artifact owing to its sensitivity toward the real space electron density.

  5. Magnetic-Field-Response Measurement-Acquisition System

    NASA Technical Reports Server (NTRS)

    Woodward, Stanley E.; Shams, Qamar A.; Fox, Robert L.; Taylor, Bryant D.

    2006-01-01

    A measurement-acquisition system uses magnetic fields to power sensors and to acquire measurements from sensors. The system alleviates many shortcomings of traditional measurement-acquisition systems, which include a finite number of measurement channels, weight penalty associated with wires, use limited to a single type of measurement, wire degradation due to wear or chemical decay, and the logistics needed to add new sensors. Eliminating wiring for acquiring measurements can alleviate potential hazards associated with wires, such as damaged wires becoming ignition sources due to arcing. The sensors are designed as electrically passive inductive-capacitive or passive inductive-capacitive-resistive circuits that produce magnetic-field-responses. One or more electrical parameters (inductance, capacitance, and resistance) of each sensor can be variable and corresponds to a measured physical state of interest. The magnetic-field- response attributes (frequency, amplitude, and bandwidth) of the inductor correspond to the states of physical properties for which each sensor measures. For each sensor, the measurement-acquisition system produces a series of increasing magnetic-field harmonics within a frequency range dedicated to that sensor. For each harmonic, an antenna electrically coupled to an oscillating current (the frequency of which is that of the harmonic) produces an oscillating magnetic field. Faraday induction via the harmonic magnetic fields produces an electromotive force and therefore a current in the sensor. Once electrically active, the sensor produces its own harmonic magnetic field as the inductor stores and releases magnetic energy. The antenna of the measurement- acquisition system is switched from a transmitting to a receiving mode to acquire the magnetic-field response of the sensor. The rectified amplitude of the received response is compared to previous responses to prior transmitted harmonics, to ascertain if the measurement system has detected a

  6. Indoor Positioning System Using Magnetic Field Map Navigation and an Encoder System

    PubMed Central

    Kim, Han-Sol; Seo, Woojin; Baek, Kwang-Ryul

    2017-01-01

    In the indoor environment, variation of the magnetic field is caused by building structures, and magnetic field map navigation is based on this feature. In order to estimate position using this navigation, a three-axis magnetic field must be measured at every point to build a magnetic field map. After the magnetic field map is obtained, the position of the mobile robot can be estimated with a likelihood function whereby the measured magnetic field data and the magnetic field map are used. However, if only magnetic field map navigation is used, the estimated position can have large errors. In order to improve performance, we propose a particle filter system that integrates magnetic field map navigation and an encoder system. In this paper, multiple magnetic sensors and three magnetic field maps (a horizontal intensity map, a vertical intensity map, and a direction information map) are used to update the weights of particles. As a result, the proposed system estimates the position and orientation of a mobile robot more accurately than previous systems. Also, when the number of magnetic sensors increases, this paper shows that system performance improves. Finally, experiment results are shown from the proposed system that was implemented and evaluated. PMID:28327513

  7. Indoor Positioning System Using Magnetic Field Map Navigation and an Encoder System.

    PubMed

    Kim, Han-Sol; Seo, Woojin; Baek, Kwang-Ryul

    2017-03-22

    In the indoor environment, variation of the magnetic field is caused by building structures, and magnetic field map navigation is based on this feature. In order to estimate position using this navigation, a three-axis magnetic field must be measured at every point to build a magnetic field map. After the magnetic field map is obtained, the position of the mobile robot can be estimated with a likelihood function whereby the measured magnetic field data and the magnetic field map are used. However, if only magnetic field map navigation is used, the estimated position can have large errors. In order to improve performance, we propose a particle filter system that integrates magnetic field map navigation and an encoder system. In this paper, multiple magnetic sensors and three magnetic field maps (a horizontal intensity map, a vertical intensity map, and a direction information map) are used to update the weights of particles. As a result, the proposed system estimates the position and orientation of a mobile robot more accurately than previous systems. Also, when the number of magnetic sensors increases, this paper shows that system performance improves. Finally, experiment results are shown from the proposed system that was implemented and evaluated.

  8. Performance evaluation of infrared imaging system in field test

    NASA Astrophysics Data System (ADS)

    Wang, Chensheng; Guo, Xiaodong; Ren, Tingting; Zhang, Zhi-jie

    2014-11-01

    Infrared imaging system has been applied widely in both military and civilian fields. Since the infrared imager has various types and different parameters, for system manufacturers and customers, there is great demand for evaluating the performance of IR imaging systems with a standard tool or platform. Since the first generation IR imager was developed, the standard method to assess the performance has been the MRTD or related improved methods which are not perfect adaptable for current linear scanning imager or 2D staring imager based on FPA detector. For this problem, this paper describes an evaluation method based on the triangular orientation discrimination metric which is considered as the effective and emerging method to evaluate the synthesis performance of EO system. To realize the evaluation in field test, an experiment instrument is developed. And considering the importance of operational environment, the field test is carried in practical atmospheric environment. The test imagers include panoramic imaging system and staring imaging systems with different optics and detectors parameters (both cooled and uncooled). After showing the instrument and experiment setup, the experiment results are shown. The target range performance is analyzed and discussed. In data analysis part, the article gives the range prediction values obtained from TOD method, MRTD method and practical experiment, and shows the analysis and results discussion. The experimental results prove the effectiveness of this evaluation tool, and it can be taken as a platform to give the uniform performance prediction reference.

  9. Systemic regulation of photosynthetic function in field-grown sorghum.

    PubMed

    Li, Tao; Liu, Yujun; Shi, Lei; Jiang, Chuangdao

    2015-09-01

    The photosynthetic characteristics of developing leaves of plants grown under artificial conditions are, to some extent, regulated systemically by mature leaves; however, whether systemic regulation of photosynthesis occurs in field-grown crops is unclear. To explore this question, we investigated the effects of planting density on growth characteristics, gas exchange, leaf nitrogen concentration and chlorophyll a fluorescence in field-grown sorghum (Sorghum bicolor L.). Our results showed that close planting resulted in a marked decline in light intensity in lower canopy. Sorghum plants grown at a high planting density had lower net photosynthetic rate (Pn), stomatal conductance (Gs), and transpiration rate (E) than plants grown at a low planting density. Moreover, in the absence of mineral deficiency, close planting induced a slight increase in leaf nitrogen concentration. The decreased photosynthesis in leaves of the lower canopy at high planting density was caused mainly by the low light. However, newly developed leaves exposed to high light in the upper canopy of plants grown at high planting density also exhibited a distinct decline in photosynthesis relative to plants grown at low planting density. Based on these results, the photosynthetic function of the newly developed leaves in the upper canopy was not determined fully by their own high light environment. Accordingly, we suggest that the photosynthetic function of newly developed leaves in the upper canopy of field-grown sorghum plants is regulated systemically by the lower canopy leaves. The differences in systemic regulation of photosynthesis were also discussed between field conditions and artificial conditions.

  10. Field Evaluation of a Mini Learning Resource Aided Instruction System.

    ERIC Educational Resources Information Center

    Attala, Emile E.; Howard, James A.

    Very little work has been done in the broad field of computer-assisted instruction (CAI) to exploring the use of a minicomputer as another learning resource in the instructional process. Accordingly a cost-effective Learning Resource Aided Instruction (LRAI) System centered around a Data General NOVA minicomputer augmented with slide…

  11. Information on the Metric System and Related Fields.

    ERIC Educational Resources Information Center

    National Aeronautics and Space Administration, Huntsville, AL. George C. Marshall Space Flight Center.

    Contained in this guide are announcements of references and audio-visual courses on the metric system and related fields available at the Marshall Space Flight Center. Included by sectional entries are listings of: (1) books, (2) reports, papers and articles, (3) periodicals, (4) film strips, (5) posters, (6) education and training courses, (7)…

  12. Results of field tests of a transportable calorimeter assay system

    SciTech Connect

    Rakel, D.A.; Lemming, J.F.; Rodenburg, W.W.; Duff, M.F.; Jarvis, J.Y.

    1981-01-01

    A transportable calorimetric assay system, developed for use by US Department of Energy inspectors, is described. The results of field tests at three DOE sites are presented. The samples measured in these tests represent a variety of forms (ash, oxide, metal buttons), isotopic composition, and total plutonium content.

  13. The American Legal System: A Field Study Approach.

    ERIC Educational Resources Information Center

    Milwaukee Public Schools, WI. Div. of Curriculum and Instruction.

    The document presents an outline for a high school legal education program which emphasizes field experiences. The program is called the American Legal System Satellite Center, and is designed to provide students with experiential knowledge of the functions, procedures, and facets of law; to expose them to a wide range of law-related career…

  14. WATER DISTRIBUTION SYSTEM ANALYSIS: FIELD STUDIES, MODELING AND MANAGEMENT

    EPA Science Inventory

    The user‘s guide entitled “Water Distribution System Analysis: Field Studies, Modeling and Management” is a reference guide for water utilities and an extensive summarization of information designed to provide drinking water utility personnel (and related consultants and research...

  15. Wireless GPS system for module fiber quality mapping: System improvement and field testing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A wireless GPS system for module-level fiber quality mapping has been developed at Texas A&M University. In its complete form, it includes subsystems for harvesters, boll buggies, and module builders. The system was field tested on a producer's farm near Plains, Texas, in 2006. The field test identi...

  16. Wireless GPS system for module-level fiber quality mapping: System improvement and field testing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A wireless GPS system for module-level fiber quality mapping has been developed at Texas A&M University. In its complete form, it includes subsystems for harvesters, boll buggies, and module builders. The system was field tested on a producer’s farm near Plains, Texas, in 2006. The field test identi...

  17. A prototype tap test imaging system: Initial field test results

    NASA Astrophysics Data System (ADS)

    Peters, J. J.; Barnard, D. J.; Hudelson, N. A.; Simpson, T. S.; Hsu, D. K.

    2000-05-01

    This paper describes a simple, field-worthy tap test imaging system that gives quantitative information about the size, shape, and severity of defects and damages. The system consists of an accelerometer, electronic circuits for conditioning the signal and measuring the impact duration, a laptop PC and data acquisition and processing software. The images are generated manually by tapping on a grid printed on a plastic sheet laid over the part's surface. A mechanized scanner is currently under development. The prototype has produced images for a variety of aircraft composite and metal honeycomb structures containing flaws, damages, and repairs. Images of the local contact stiffness, deduced from the impact duration using a spring model, revealed quantitatively the stiffness reduction due to flaws and damages, as well as the stiffness enhancement due to substructures. The system has been field tested on commercial and military aircraft as well as rotor blades and engine decks on helicopters. Field test results will be shown and the operation of the system will be demonstrated.—This material is based upon work supported by the Federal Aviation Administration under Contract #DTFA03-98-D-00008, Delivery Order No. IA016 and performed at Iowa State University's Center for NDE as part of the Center for Aviation Systems Reliability program.

  18. Field Performance of Photovoltaic Systems in the Tucson Desert

    NASA Astrophysics Data System (ADS)

    Orsburn, Sean; Brooks, Adria; Cormode, Daniel; Greenberg, James; Hardesty, Garrett; Lonij, Vincent; Salhab, Anas; St. Germaine, Tyler; Torres, Gabe; Cronin, Alexander

    2011-10-01

    At the Tucson Electric Power (TEP) solar test yard, over 20 different grid-connected photovoltaic (PV) systems are being tested. The goal at the TEP solar test yard is to measure and model real-world performance of PV systems and to benchmark new technologies such as holographic concentrators. By studying voltage and current produced by the PV systems as a function of incident irradiance, and module temperature, we can compare our measurements of field-performance (in a harsh desert environment) to manufacturer specifications (determined under laboratory conditions). In order to measure high-voltage and high-current signals, we designed and built reliable, accurate sensors that can handle extreme desert temperatures. We will present several benchmarks of sensors in a controlled environment, including shunt resistors and Hall-effect current sensors, to determine temperature drift and accuracy. Finally we will present preliminary field measurements of PV performance for several different PV technologies.

  19. Hydrotest measurement system for gas lines gets field trials

    SciTech Connect

    Hodges, A.H. )

    1989-08-07

    Texas Gas Transmission Co., Owensboro, Ky., has developed a tool for recording and documenting the performance of hydrostatic testing. Texas Gas conducted field tests during the summer of 1988 and has continued those tests this year. The hydrostatic-test measurement system (HTMS) is designed to be more compact and easier to use than existing systems. With a Tandy 200 portable lap-top computer, software developed in-house, and other company-fabricated interface hardware, the portable data-acquisition system will measure and record field hydrostatic-test data. After the test, the computer will generate a stress-strain plot (pressure-vs.-gallon count) with a graphics plotter and print the test data.

  20. Easily installable behavioral monitoring system with electric field sensor.

    PubMed

    Tsukamoto, Sosuke; Machida, Yuichiro; Kameda, Noriyuki; Hoshino, Hiroshi; Tamura, Toshiyo

    2007-01-01

    This paper describes a wireless behavioral monitoring system equipped with an electric field sensor. The sensor unit was designed to obtain information regarding the usage of home electric appliances such as the television, microwave oven, coffee maker, etc. by measuring the electric field surrounding them. It is assumed that these usage statistics could provide information regarding the indoor behavior of a subject. Since the sensor can be used by simply attaching it to an appliance and does not require any wiring for its installation, this system can be temporarily installed in any ordinary house. A simple interface for selecting the threshold value of appliances' power on/off states was introduced. The experimental results reveal that the proposed system can be installed by individuals in their residences in a short time and the usage statistics of home appliances can be gathered.

  1. Fielding The Automated Container Offering System: An interim report

    SciTech Connect

    Dixon, B. ); Rochette, D. ); Crandell, J. )

    1990-01-01

    The Automated Container Offering System (TACOS) is a cargo booking assistant currently being fielded in the International Traffic Directorate of the Military Traffic Management Command (MTMC). The expert system automates the selection process for type and size of SEAVAN containers, ports, carrier, and ship for containerized military cargo moving from the continental US to Europe. It is designed to perform all processing on simple cases and provide assistance to the human booker on complex cases. MTMC processes requests for {approximately}1000 containers per week on these routes. This paper is a case history which describes factors guiding development of TACOS to illustrate several themes which occur in other (military) logistics expert system projects.

  2. A complexity classification of spin systems with an external field.

    PubMed

    Goldberg, Leslie Ann; Jerrum, Mark

    2015-10-27

    We study the computational complexity of approximating the partition function of a q-state spin system with an external field. There are just three possible levels of computational difficulty, depending on the interaction strengths between adjacent spins: (i) efficiently exactly computable, (ii) equivalent to the ferromagnetic Ising model, and (iii) equivalent to the antiferromagnetic Ising model. Thus, every nontrivial q-state spin system, irrespective of the number q of spins, is computationally equivalent to one of two fundamental two-state spin systems.

  3. Aging in the two-dimensional random-field systems

    NASA Astrophysics Data System (ADS)

    Cheng, Xiang; Ma, Tianyu; Urazhdin, Sergei; Boettcher, Stefan

    Random fields introduced into the classical Ising and Heisenberg spin models can roughen the energy landscape, leading to complex nonequilibrium dynamics. The effects of random fields on magnetism have been previously studied in the context of dilute antiferromagnets (AF), impure substrates, and magnetic alloys [ 1 ] . We utilized random-field spin models to simulate the observed magnetic aging in thin-film ferromagnet/antiferromagnet (F/AF) bilayers. Our experiments show extremely slow cooperative relaxation over a wide range of temperatures and magnetic fields [ 2 ] . In our simulations, the experimental system is coarse-grained into a random field Ising model on a 2D square lattice. Monte Carlo simulations indicate that aging processes may be associated with the glassy evolution of the magnetic domain walls, due to the pinning by the random fields. The scaling of the simulated aging agrees well with experiments. Both are consistent with either a small power-law or logarithmic dependence on time. We further discuss the topological effects on aging due to the dimensional crossover from the Ising to the Heisenberg regime. Supported through NSF grant DMR-1207431.

  4. Logging system adds value to field rejuvenation efforts

    SciTech Connect

    Peters, D.; Bartenhagen, K.; Santolamazza, A.

    1997-11-01

    As with any rejuvenation scheme, the first step is always identification and evaluation of potential producible reserves. But economic and physical factors made evaluation using traditional logging techniques problematic. The constraints that inhibited earlier logging tools have been addressed by a new, compact integrated system called Platform Express (PEX). Oil companies operating in two of the most mature producing regions of the US, the Hugoton-Panhandle Field and the Southwest Nena Lucia Field in West Texas, discuss the physical and economic advantages they are reaping using PEX technologies. Hugoton-Panhandle Field, discovered around 1920, sprawls across parts of three south-central states and has been one of the world`s largest gas producers. Despite continuing pressure declines in this aging gas giant, the entire region has undergone restoration in the last few years. In its Kansas portions, a modest oil production has almost doubled since 1990 and a steep gas decline has been completely turned around. These production gains have come from an active program of recompletions, the deepening of old holes and new drilling. The story in the southwest Nena Lucia Field is much the same. Operator Oryx Energy has been active in the field, located west of Abilene, Texas, since its discovery in the 1950s. The goal with this field is to use advanced technologies to reverse the production declines that began years ago. Such a reversal began in mid-1996 and has been sustained thus far.

  5. Wide field of view infrared imaging system design

    NASA Astrophysics Data System (ADS)

    Rogala, Eric W.

    2004-08-01

    In the design of optical systems, simple straightforward requirements are often complicated by unusual and unique constraints. In this particular case a design mapping a 20° square field of view onto a CCD sensor is complicated by the requirement that the wide field of view must not vignette through a narrow-diameter, finite-length cylindrical aperture. Furthermore, the design must use off-the-shelf optics available from any major vendor. The imaging system is designed to operate in the near IR. The 20° square field of view must pass through a 20.32mm diameter, 40mm long cylindrical tube without vignetting. This constraint prohibits the use of a simple achromat whose back focal length would place the image within the cylindrical tube. Two design approaches are discussed, a Keplerian telescope with a field lens, and a reverse telephoto system. Matlab programs have been written that evaluate the first-order optical principles to arrive at a design solution space. Representative solutions are then evaluated in Zemax using the built-in lens catalog to select appropriate lenses. The results show the advantages and limitations of each particular design approach.

  6. Robust mean field games for coupled Markov jump linear systems

    NASA Astrophysics Data System (ADS)

    Moon, Jun; Başar, Tamer

    2016-07-01

    We consider robust stochastic large population games for coupled Markov jump linear systems (MJLSs). The N agents' individual MJLSs are governed by different infinitesimal generators, and are affected not only by the control input but also by an individual disturbance (or adversarial) input. The mean field term, representing the average behaviour of N agents, is included in the individual worst-case cost function to capture coupling effects among agents. To circumvent the computational complexity and analyse the worst-case effect of the disturbance, we use robust mean field game theory to design low-complexity robust decentralised controllers and to characterise the associated worst-case disturbance. We show that with the individual robust decentralised controller and the corresponding worst-case disturbance, which constitute a saddle-point solution to a generic stochastic differential game for MJLSs, the actual mean field behaviour can be approximated by a deterministic function which is a fixed-point solution to the constructed mean field system. We further show that the closed-loop system is uniformly stable independent of N, and an approximate optimality can be obtained in the sense of ε-Nash equilibrium, where ε can be taken to be arbitrarily close to zero as N becomes sufficiently large. A numerical example is included to illustrate the results.

  7. 3D temperature field reconstruction using ultrasound sensing system

    NASA Astrophysics Data System (ADS)

    Liu, Yuqian; Ma, Tong; Cao, Chengyu; Wang, Xingwei

    2016-04-01

    3D temperature field reconstruction is of practical interest to the power, transportation and aviation industries and it also opens up opportunities for real time control or optimization of high temperature fluid or combustion process. In our paper, a new distributed optical fiber sensing system consisting of a series of elements will be used to generate and receive acoustic signals. This system is the first active temperature field sensing system that features the advantages of the optical fiber sensors (distributed sensing capability) and the acoustic sensors (non-contact measurement). Signals along multiple paths will be measured simultaneously enabled by a code division multiple access (CDMA) technique. Then a proposed Gaussian Radial Basis Functions (GRBF)-based approach can approximate the temperature field as a finite summation of space-dependent basis functions and time-dependent coefficients. The travel time of the acoustic signals depends on the temperature of the media. On this basis, the Gaussian functions are integrated along a number of paths which are determined by the number and distribution of sensors. The inversion problem to estimate the unknown parameters of the Gaussian functions can be solved with the measured times-of-flight (ToF) of acoustic waves and the length of propagation paths using the recursive least square method (RLS). The simulation results show an approximation error less than 2% in 2D and 5% in 3D respectively. It demonstrates the availability and efficiency of our proposed 3D temperature field reconstruction mechanism.

  8. Convective Systems Observed and Simulated During TRMM Field Campaigns

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Recently completed TRMM field campaigns (TEFLUN1998, SCSMEX-1998, TRMM.LBA-1999, and KWAJEX 1999) have obtained direct measurements of microphysical data associated with convective systems from various geographical locations. These TRMM field experiments were designed to contribute to fundamental understanding of cloud dynamics and microphysics, as well as for validation,, testing assumptions and error estimates of cloud-resolving models, forward radiative transfer models, algorithms used to estimate rainfall statistics and vertical structure of precipitation and latent heating from both surface-based radar and satellites.

  9. Wide-field turbulence imaging with beam emission spectroscopy

    SciTech Connect

    McKee, G. R.; Fonck, R. J.; Uzun-Kaymak, I. U.; Yan, Z.; Shafer, M. W.

    2010-10-15

    Imaging of the size, shape, time-averaged, and time-resolved dynamics of long-wavelength density turbulence structures is accomplished with an expanded, high-sensitivity, wide-field beam emission spectroscopy (BES) diagnostic on DIII-D. A 64-channel BES system is configured with an 8x8 grid of discrete channels that image an approximately 7x9 cm region at the outboard midplane. The grid covers multiple correlation lengths and each channel shape matches the measured radial-poloidal correlation length asymmetry of turbulent eddies. The wide field 8x8 imaging capability allows for sampling of essentially the full two-dimensional spatial correlation function for typical plasma conditions. The sampled area can be radially scanned over 0.4

  10. 4D light-field sensing system for people counting

    NASA Astrophysics Data System (ADS)

    Hou, Guangqi; Zhang, Chi; Wang, Yunlong; Sun, Zhenan

    2016-03-01

    Counting the number of people is still an important task in social security applications, and a few methods based on video surveillance have been proposed in recent years. In this paper, we design a novel optical sensing system to directly acquire the depth map of the scene from one light-field camera. The light-field sensing system can count the number of people crossing the passageway, and record the direction and intensity of rays at a snapshot without any assistant light devices. Depth maps are extracted from the raw light-ray sensing data. Our smart sensing system is equipped with a passive imaging sensor, which is able to naturally discern the depth difference between the head and shoulders for each person. Then a human model is built. Through detecting the human model from light-field images, the number of people passing the scene can be counted rapidly. We verify the feasibility of the sensing system as well as the accuracy by capturing real-world scenes passing single and multiple people under natural illumination.

  11. Scada system oversees Canadian H sub 2 S field, pipelines

    SciTech Connect

    Greenslade, J.G. ); Wichert, E. )

    1992-05-25

    Important new safety and operational features and some industry firsts are employed in a PC-based supervisory control and data acquisition (scada) system at Phillips Petroleum Resources Ltd.'s Ghost River sour-gas field and pipeline in a populated area near Calgary. This paper reports on the scada system monitors and controls wells, line-heaters, pumps, and alarm and shutdown systems. facilities are operated on a partially attended basis. Operators carry cellular telephones and laptop computers equipped with internal modems to enable them to receive alarms and take appropriate action promptly. Several safety features are incorporated into the alarm and shutdown system. All aboveground facilities are equipped with atmospheric monitors for H{sub 2}S. Leak detection is inferred from continuous material-balance computation. Should a sour-gas leak be suspected, an automated resident-notification system provides early notice by telephone to potentially affected residents.

  12. NASA JSC water monitor system: City of Houston field demonstration

    NASA Technical Reports Server (NTRS)

    Taylor, R. E.; Jeffers, E. L.; Fricks, D. H.

    1979-01-01

    A water quality monitoring system with on-line and real time operation similar to the function in a spacecraft was investigated. A system with the capability to determine conformance to future high effluent quality standards and to increase the potential for reclamation and reuse of water was designed. Although all system capabilities were not verified in the initial field trial, fully automated operation over a sustained period with only routine manual adjustments was accomplished. Two major points were demonstrated: (1) the water monitor system has great potential in water monitoring and/or process control applications; and (2) the water monitor system represents a vast improvement over conventional (grab sample) water monitoring techniques.

  13. Field demonstration of the ICE 250[trademark] Cleaning System

    SciTech Connect

    Johnston, J.L.; Jackson, L.M.

    1999-10-05

    The ICE 250[trademark] Cleaning System was engineered to convert water into small ice particles for use in cleaning and decontamination applications. Ice crystals are produced in a special icemaker and pressured through a hose-nozzle onto the surface to be cleaned. The Rocky Mountain Oilfield Testing Center and Ice Cleaning Systems, Inc., conducted a test of this system at Naval Petroleum Reserve No. 3 to evaluate the system's cleaning capabilities in an oil field environment. Equipment cleaned included an oil storage tank, a rod pumping unit, a road grader, and a wellhead. Contaminants were unrefined sour crude oil, hydraulic fluid, paraffin, and dirt, occurring separately and as mixtures. In all four demonstration cleaning tasks, the ICE 250 System effectively removed surface contaminant mixtures in a timely manner and left no oily residue. A minimal amount of waste moistur2048s generated, thereby reducing cleanup and disposal costs.

  14. Field demonstration of the ICE 250{trademark} Cleaning System

    SciTech Connect

    Johnston, J.L.; Jackson, L.M.

    1999-10-05

    The ICE 250{trademark} Cleaning System was engineered to convert water into small ice particles for use in cleaning and decontamination applications. Ice crystals are produced in a special icemaker and pressured through a hose-nozzle onto the surface to be cleaned. The Rocky Mountain Oilfield Testing Center and Ice Cleaning Systems, Inc., conducted a test of this system at Naval Petroleum Reserve No. 3 to evaluate the system's cleaning capabilities in an oil field environment. Equipment cleaned included an oil storage tank, a rod pumping unit, a road grader, and a wellhead. Contaminants were unrefined sour crude oil, hydraulic fluid, paraffin, and dirt, occurring separately and as mixtures. In all four demonstration cleaning tasks, the ICE 250 System effectively removed surface contaminant mixtures in a timely manner and left no oily residue. A minimal amount of waste moisture was generated, thereby reducing cleanup and disposal costs.

  15. Simple System to Measure the Earth's Magnetic Field

    NASA Astrophysics Data System (ADS)

    Akoglu, R.; Halilsoy, M.; Mazharimousavi, S. Habib

    2010-11-01

    Our aim in this proposal is to use Faraday's law of induction as a simple lecture demonstration to measure the Earths magnetic field (B). This will also enable the students to learn about how electric power is generated from rotational motion. Obviously the idea is not original, yet it may be attractive in the sense that no sophisticated devices are used. All the equipment needed is available in an elementary physics laboratory and is displayed in Fig. 1. The square wooden coil and handmade belt system to rotate the coil may require some craftsmanship; once made, it can be used for years. Using a compass, we first orient the table parallel to the direction of the Earth's horizontal component of B field. This is necessary to maximize the Earth's field which can suppress the noise effects as much as possible. It is preferable to minimize also any environmental effects by conducting the experiment away from power lines, if possible of course.

  16. Process system and method for fabricating submicron field emission cathodes

    DOEpatents

    Jankowski, A.F.; Hayes, J.P.

    1998-05-05

    A process method and system for making field emission cathodes exists. The deposition source divergence is controlled to produce field emission cathodes with height-to-base aspect ratios that are uniform over large substrate surface areas while using very short source-to-substrate distances. The rate of hole closure is controlled from the cone source. The substrate surface is coated in well defined increments. The deposition source is apertured to coat pixel areas on the substrate. The entire substrate is coated using a manipulator to incrementally move the whole substrate surface past the deposition source. Either collimated sputtering or evaporative deposition sources can be used. The position of the aperture and its size and shape are used to control the field emission cathode size and shape. 3 figs.

  17. Process system and method for fabricating submicron field emission cathodes

    DOEpatents

    Jankowski, Alan F.; Hayes, Jeffrey P.

    1998-01-01

    A process method and system for making field emission cathodes exists. The deposition source divergence is controlled to produce field emission cathodes with height-to-base aspect ratios that are uniform over large substrate surface areas while using very short source-to-substrate distances. The rate of hole closure is controlled from the cone source. The substrate surface is coated in well defined increments. The deposition source is apertured to coat pixel areas on the substrate. The entire substrate is coated using a manipulator to incrementally move the whole substrate surface past the deposition source. Either collimated sputtering or evaporative deposition sources can be used. The position of the aperture and its size and shape are used to control the field emission cathode size and shape.

  18. Progress in crosswell induction imaging for EOR: field system design and field testing

    SciTech Connect

    Kirkendall, B A; Lewis, J P; Hunter, S L; Harben, P E

    1999-03-04

    At Lawrence Livermore National Laboratory (LLNL), we are continuing our effort to develop improved crosswell low-frequency electromagnetic imaging techniques, which are used to map in situ steamflood and waterflood movement during enhanced oil recovery (EOR) operations. Toward this effort, we procured two new borehole-logging field vehicles, and developed and integrated new crosswell electromagnetic transmitter and receiver data acquisition and control systems into these vehicles. We tested this new acquisition system by conducting a suite of background measurements and repeatability experiments at the Richmond Field Station in Richmond, California. Repeatability of a given scan in which the receiver was fixed and the transmitter position was varied over 60 m in 0.2-m increments resulted in amplitude differences of less than 0.6% and phase differences of less than 0.54 deg. Forward modeling produced a resistivity map fully consistent with well log data from the Richmond Field Station. In addition, modeling results suggest (1) that residual high-conductivity saltwater, injected in 1993 and pumped out in 1995, is present at the site and (2) that it has diffused outward from the original target strata. To develop crosswell electromagnetic imaging into a viable commercial product, our future research must be a two-fold approach: (1) improved quantification of system noise through experiments such as ferromagnetic core characterization as a function of temperature, and (2) development of procedures and codes to account for steel-cased hole scenarios.

  19. Screening of Electric field in a Variable Range Hopping System

    NASA Astrophysics Data System (ADS)

    Prigodin, Vladimir; Epstein, Arthur

    2003-03-01

    Recent report of a field effect in conducting polymers [1] initiated a large interest. The "field effect" can not be explained only by electrochemical dedoping of polymers. Also the field effect is impossible to understand within a model of homogeneous conductor because of the atomic scale of Debye radius. We discuss the penetration of electric field in a system in which charge transport is provided by variable range hopping (VRH). The majority of carriers are localized and contribute to the dielectric constant. An exponentially small fraction of carriers are mobile and screens the external field. Our estimate shows that the screening length for conducting polymers can be essentially larger than in metals but is still not enough to explain the experimental data. A combination of different factors including the inhomogeneous (granular) structure of conducting polymers may control the observable phenomena. J. Lu et al., J. Appl. Phys. XX, in press (2002); A.J. Epstein et al., Current Appl. Lett. 2, 339 (2002); M. Ishihara and H. Okuzaki, Synth. Met. XX, in press (2003).

  20. Classical action functional for the system of fields and wormholes

    SciTech Connect

    Hajicek, P.

    1982-12-15

    We lay down foundations of the quantum theory of wormholes for the model Einstein-Maxwell system. The generalization of the quantum theory of solitons to wormholes is not straightforward, because the fields are singular at r = 0. We propose to cut away the nonphysical part of the spacetime along the horizons and to impose boundary conditions at the resulting boundary of Cauchy surfaces. The boundary conditions are chosen such that (a) there is an action functional for the fields, (b) Poisson brackets of the boundary-fixed quantities with each other vanish, and (c) the soliton solution is unique. We study the action functional, find the surface terms, and, using the method of Regge and Teitelboim, extract the motion of the soliton. We show how the gauge group of the system is extended and find some properties of the additional gauge conditions. Finally, the soliton solution is written in the form in which all boundary and gauge conditions are satisfied.

  1. Portable System for Field-Feeding Greywater Remediation and Recycling

    DTIC Science & Technology

    2006-07-01

    with greywater reuse regulations2 base their water quality standards on the secondary treatment standard. In addition, each system’s process rate...to the system and converted to greywater . Of this added water, 80% is cleaned for reuse while 20% is unusable concentrate that requires backhauling...Field- Feeding Greywater Remediation and Recycling July 2006 Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the

  2. Three-Body Nuclear Systems in Pionless Effective Field Theory

    NASA Astrophysics Data System (ADS)

    Vanasse, Jared

    2016-03-01

    New perturbative techniques for three-body systems with contact interactions are discussed. Their application to pionless effective field theory (EF{Tnot π }) for nd scattering is shown, and their extension to bound states addressed. With the extension to bound states a leading-order EF{Tnot π } calculation of the triton charge radius and novel treatments of three-body forces are discussed.

  3. Development of high poloidal beta, steady-state scenario with ITER-like W divertor on EAST

    NASA Astrophysics Data System (ADS)

    Garofalo, A. M.; Lanctot, M.; Gong, X. Z.; Ding, S.; Li, G.; Liu, H.; Lyu, B.; Qian, J.; Bonoli, P. T.; Shiraiwa, S.; Holcomb, C.; McClenaghan, J.

    2016-10-01

    Experiments on EAST have started to adapt the fully-noninductive high poloidal beta scenario developed on DIII-D, in order to demonstrate steady state tokamak operation at high performance on metal walls. Unlike on DIII-D, where the creation of a broad current profile requires early heating at low density, on EAST a broad current profile can be obtained simply by increasing the electron density, when most of the current drive is provided by lower hybrid wave. Systematic scans yield lower internal inductance with higher density. The hypothesis is that the LHCD profile becomes more off-axis with higher density. With the newly commissioned POINT (polarimeter-interferometer) diagnostic for q-profile measurements, these experiments enable strict tests of LHCD deposition models. Supported by US DOE under DE-SC0010685, DE-SC0010492 DE-FC02-04ER54698, DE-AC02-09-CH11466, DE-AC52-07NA27344, DE-AC05-00OR22725, and the National Magnetic Confinement Fusion Program of China (No. 2015GB110001 and 2015GB102000).

  4. Field operations with cesium clocks in HF navigation systems

    NASA Technical Reports Server (NTRS)

    Christy, E. H.; Clayton, D. A.

    1982-01-01

    Networks of HF phase comparison marine navigation stations employing cesium clocks are discussed. The largest permanent network is in the Gulf of Mexico where some fourteen base stations are continuously active and others are activated as needed. These HF phase comparison systems, which operate on a single transmission path, require a clock on the mobile unit as well. Inventory consists of upwards of 70 clocks from two different manufacturers. The maintenance of this network as an operating system requires a coordinated effort involving clock preparation, clock environment control, station performance monitoring and field service.

  5. System having unmodulated flux locked loop for measuring magnetic fields

    DOEpatents

    Ganther, Jr., Kenneth R.; Snapp, Lowell D.

    2006-08-15

    A system (10) for measuring magnetic fields, wherein the system (10) comprises an unmodulated or direct-feedback flux locked loop (12) connected by first and second unbalanced RF coaxial transmission lines (16a, 16b) to a superconducting quantum interference device (14). The FLL (12) operates for the most part in a room-temperature or non-cryogenic environment, while the SQUID (14) operates in a cryogenic environment, with the first and second lines (16a, 16b) extending between these two operating environments.

  6. Field joint environmental protection system vibration/pressurization qualification

    NASA Technical Reports Server (NTRS)

    Cook, M.

    1989-01-01

    The procedures used and results obtained from vibration testing the redesigned solid rocket motor (RSRM) field joint environmental protection system (FJEPS), hereafter referred to as the joint protection system (JPS) are documented. The major purposes were to certify that the flight-designed JPS will withstand the dynamic environmental conditions of the redesigned solid rocket booster, and to certify that the cartridge check valve (vent valve) will relieve pressure build-up under the JPS during the initial 120 sec of flight. Also, an evaluation of the extruded cork insulation bonding was performed after the vibration testing.

  7. Practical approaches to field problems of stationary combustion systems

    SciTech Connect

    Lee, S.W.

    1997-09-01

    The CANMET Energy Technology Centre (CETC) business plan dictates collaboration with industrial clients and other government agencies to promote energy efficiency, health and safety, pollution reduction and productivity enhancement. The Advanced Combustion Technologies group of CETC provides consultation to numerous organizations in combustion related areas by conducting laboratory and field investigations of fossil fuel-fired combustion equipment. CETC, with its modern research facilities and technical expertise, has taken this practical approach since the seventies and has assisted many organizations in overcoming field problems and in providing cost saving measures and improved profit margins. This paper presents a few selected research projects conducted for industrial clients in north and central America. The combustion systems investigated are mostly liquid fuel fired, with the exception of the utility boiler which was coal-fired. The key areas involved include fuel quality, fuel storage/delivery system contamination, waste derived oils, crude oil combustion, unacceptable pollutant emissions, ambient soot deposition, slagging, fouling, boiler component degradation, and particulate characterization. Some of the practical approaches taken to remedy these field problems on several combustion systems including residential, commercial and industrial scale units are discussed.

  8. Classical-field methods for atom-molecule systems

    NASA Astrophysics Data System (ADS)

    Sahlberg, Catarina E.; Gardiner, C. W.

    2013-02-01

    We extend classical-field methods [Blakie , Adv. Phys.ADPHAH0001-873210.1080/00018730802564254 57, 363 (2008)] to provide a description of atom-molecule systems. We use a model of Bose-Einstein condensation of atoms close to a Feshbach resonance, in which the tunable scattering length of the atoms is described using a system of coupled atom and molecule fields [Holland , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.86.1915 86, 1915 (2001)]. We formulate the basic theoretical methods for a coupled atom-molecule system, including the determination of the phenomenological parameters in our system, the Thomas-Fermi description of Bose-Einstein condensate, the Bogoliubov-de Gennes equations, and the Bogoliubov excitation spectrum for a homogenous condensed system. We apply this formalism to the special case of Bragg scattering from a uniform condensate and find that for moderate and large scattering lengths, there is a dramatic difference in the shift of the peak of the Bragg spectra, compared to that based on a structureless atom model. The result is compatible with the experimental results of Papp [Phys. Rev. LettPRLTAO0031-900710.1103/PhysRevLett.101.135301 101, 135301 (2008)] for Bragg scattering from a nonuniform condensate.

  9. Marine Tactical Command and Control System (MTACCS) Field Development System-1 (FDS-1) assessment: Final report

    SciTech Connect

    Avery, L.W.; Hunt, S.T.; Savage, S.F. ); McLaughlin, P.D.; Shepdard, A.P.; Worl, J.C. )

    1992-04-01

    The United State Marine Corps (USMC) is continuing the development and fielding of the Marine Corps Tactical Command and Control System (MTACCS), a system which exists in varying states of development, fielding, or modernization. MTACCS is currently composed of the following components: Tactical Combat Operations System (TCO) for ground command and control (C2), Intelligence Analysis System (IAS) with a Genser terminal connected to a TCO workstation for intelligence C2, Marine Integrated Personnel System (MIPS) and a TCO workstation using the Marine Combat Personnel System (MCPERS) software for personnel C2, Marine Integrated Logistics System (MILOGS) which is composed of the Landing Force Asset Distribution System (LFADS), the Marine Air-Ground Task Force (MAGTF) II, and a TCO terminal using the Marine Combat Logistics System (MCLOG) for logistics C2, Marine Corps Fire Support System (MCFSS) for fire support C2, and Advanced Tactical Air Command Central (ATACC) and the Improved Direct Air Support Central for aviation C2.

  10. Moffett Field Funnel and Gate TCE Treatment System: Interpretation of Field Performance using Reactive Transport Modeling

    SciTech Connect

    Yabusaki, Steven B.; Cantrell, Kirk J.; Sass, B. M.

    2001-06-30

    A multicomponent reactive transport simulator was used to understand the behavior of chemical components, including TCE and cis-1,2-DCE, in groundwater transported through the pilot-scale funnel and gate chemical treatment system at Moffett Field, California. Field observations indicated that zero-valent iron emplaced in the gate to effect the destruction of chlorinated hydrocarbons also resulted in increases in pH and hydrocarbons, as well as decreases in EH, alkalinity, dissolved O2 and CO2, and major ions (i.e., Ca, Mg, Cl, sulfate, nitrate). Of concern are chemical transformations that may reduce the effectiveness or longevity of the iron cell and/or create secondary contaminants. A coupled model of transport and reaction processes was developed to account for mobile and immobile components undergoing equilibrium and kinetic reactions including TCE degradation, parallel iron dissolution reactions, precipitation of secondary minerals, and complexation reactions. The model reproduced solution chemistry observed in the iron cell using reaction parameters from the literature and laboratory studies. Mineral precipitation in the iron zone, which is critical to correctly predicting the aqueous concentrations, was predicted to account for up to 3 percent additional mineral volume annually. Interplay between rates of transport and rates of reaction in the field was key to understanding system behavior.

  11. Role of energy systems in two intermittent field tests in women field hockey players.

    PubMed

    Lemmink, Koen A P M; Visscher, Susan H

    2006-08-01

    The energetics of 2 field tests that reflect physical performance in intermittent sports (i.e., the Interval Shuttle Sprint Test [ISST] and the Interval Shuttle Run Test [ISRT]) were examined in 21 women field hockey players. The ISST required the players to perform 10 shuttle sprints starting every 20 seconds. During the ISRT, players alternately ran 20-m shuttles for 30 seconds and walked for 15 seconds with increasing speed. Anaerobic and aerobic power tests included Wingate cycle sprints and a .V(O2)max cycle test, respectively. Based on correlation and regression analyses, it was concluded that for the ISST, anaerobic energetic pathways contribute mainly to energy supply for peak sprint time, while aerobic energetic pathways also contribute to energy supply for total sprint time. Energy during the ISRT is supplied mainly by the aerobic energy system. Depending on the aspect of physical performance a coach wants to determine, the ISST or ISRT can be used.

  12. Superconducting and hybrid systems for magnetic field shielding

    NASA Astrophysics Data System (ADS)

    Gozzelino, L.; Gerbaldo, R.; Ghigo, G.; Laviano, F.; Truccato, M.; Agostino, A.

    2016-03-01

    In this paper we investigate and compare the shielding properties of superconducting and hybrid superconducting/ferromagnetic systems, consisting of cylindrical cups with an aspect ratio of height/radius close to unity. First, we reproduced, by finite-element calculations, the induction magnetic field values measured along the symmetry axis in a superconducting (MgB2) and in a hybrid configuration (MgB2/Fe) as a function of the applied magnetic field and of the position. The calculations are carried out using the vector potential formalism, taking into account simultaneously the non-linear properties of both the superconducting and the ferromagnetic material. On the basis of the good agreement between the experimental and the computed data we apply the same model to study the influence of the geometric parameters of the ferromagnetic cup as well as of the thickness of the lateral gap between the two cups on the shielding properties of the superconducting cup. The results show that in the considered non-ideal geometry, where the edge effect in the flux penetration cannot be disregarded, the superconducting shield is always the most efficient solution at low magnetic fields. However, a partial recovery of the shielding capability of the hybrid configuration occurs if a mismatch in the open edges of the two cups is considered. In contrast, at high magnetic fields the hybrid configurations are always the most effective. In particular, the highest shielding factor was found for solutions with the ferromagnetic cup protruding over the superconducting one.

  13. Numerical Modeling of a Near-Field Scanning Optical System

    NASA Astrophysics Data System (ADS)

    Kann, Joshua Louis

    A near-field scanning optical (NFO) system utilizes a subwavelength sized aperture to illuminate a sample. The aperture raster scans the sample. During the scan, the aperture is held in proximity to the sample. At each sampling point, the integrated far-zone energy distribution is stored. This collection of data is used to generate an image of the sample's surface. The main advantage of NFO systems is their very high spatial resolution. In this dissertation a hybrid finite-difference-time-domain (FDTD)/angular spectrum code is used to study the electromagnetic and imaging properties of a NFO scanning system. In addition, a finite-difference thermal (FD-thermal) code is used to calculate the thermal properties of a NFO system. Various aperture/sample geometries are studied numerically using both TE and TM polarization within a two-dimensional metallic waveguide that forms the aperture. The spatial properties of the electric field emitted by the aperture with no sample present are greatly influenced by the polarization. In particular, the electric field with TM polarization exhibits sharp peaks near the corners of the aperture, while the field with TE polarization is smooth and peaked at the center of the aperture. For both polarizations, the electric field remains collimated for a distance comparable to the aperture size. The electric field for both polarizations is altered when a dielectric sample is placed in proximity to the aperture. It is shown that the most representative image of the sample's topography is obtained using TE polarization and the resulting total far-zone energy as the sampled data. It is also shown that simpler scalar methods do not accurately predict the imaging behavior of a NFO system. Under certain circumstances the relationship between the sample's topography and the detected image is nearly linear. Under these conditions a system transfer function is calculated. Using the transfer function, it is shown that the spatial resolution of a NFO

  14. Mean-field limit of systems with multiplicative noise.

    PubMed

    Muñoz, Miguel A; Colaiori, Francesca; Castellano, Claudio

    2005-11-01

    A detailed study of the mean-field solution of Langevin equations with multiplicative noise is presented. Three different regimes depending on noise intensity (weak, intermediate, and strong noise) are identified by performing a self-consistent calculation on a fully connected lattice. The most interesting, strong-noise, regime is shown to be intrinsically unstable with respect to the inclusion of fluctuations, as a Ginzburg criterion shows. On the other hand, the self-consistent approach is shown to be valid only in the thermodynamic limit, while for finite systems the critical behavior is found to be different. In this last case, the self-consistent field itself is broadly distributed rather than taking a well defined mean value; its fluctuations, described by an effective zero-dimensional multiplicative noise equation, govern the critical properties. These findings are obtained analytically for a fully connected graph, and verified numerically both on fully connected graphs and on random regular networks. The results presented here shed some doubt on what is the validity and meaning of a standard mean-field approach in systems with multiplicative noise in finite dimensions, where each site does not see an infinite number of neighbors, but a finite one. The implications of all this on the existence of a finite upper critical dimension for multiplicative noise and Kardar-Parisi-Zhang problems are briefly discussed.

  15. Developing accurate molecular mechanics force fields for conjugated molecular systems.

    PubMed

    Do, Hainam; Troisi, Alessandro

    2015-10-14

    A rapid method to parameterize the intramolecular component of classical force fields for complex conjugated molecules is proposed. The method is based on a procedure of force matching with a reference electronic structure calculation. It is particularly suitable for those applications where molecular dynamics simulations are used to generate structures that are therefore analysed by electronic structure methods, because it is possible to build force fields that are consistent with electronic structure calculations that follow classical simulations. Such applications are commonly encountered in organic electronics, spectroscopy of complex systems and photobiology (e.g. photosynthetic systems). We illustrate the method by parameterizing the force fields of a molecule used in molecular semiconductors (2,2-dicyanovinyl-capped S,N-heteropentacene or DCV-SN5), a polymeric semiconductor (thieno[3,2-b]thiophene-diketopyrrolopyrrole TT-DPP) and a chromophore embedded in a protein environment (15,16-dihydrobiliverdin or DBV) where several hundreds of parameters need to be optimized in parallel.

  16. DESIGN, DEVELOPMENT AND FIELD DEPLOYMENT OF A TELEOPERATED SAMPLING SYSTEM

    SciTech Connect

    Dalmaso, M; Robert Fogle, R; Tony Hicks, T; Larry Harpring, L; Daniel Odell, D

    2007-11-09

    A teleoperated sampling system for the identification, collection and retrieval of samples following the detonation of an Improvised Nuclear Device (IND) or Radiological Dispersion Devise (RDD) has been developed and tested in numerous field exercises. The system has been developed as part of the Defense Threat Reduction Agency's (DTRA) National Technical Nuclear Forensic (NTNF) Program. The system is based on a Remotec ANDROS Mark V-A1 platform. Extensive modifications and additions have been incorporated into the platform to enable it to meet the mission requirements. The Defense Science Board Task Force on Unconventional Nuclear Warfare Defense, 2000 Summer Study Volume III report recommended the Department of Defense (DOD) improve nuclear forensics capabilities to achieve accurate and fast identification and attribution. One of the strongest elements of protection is deterrence through the threat of reprisal, but to accomplish this objective a more rapid and authoritative attribution system is needed. The NTNF program provides the capability for attribution. Early on in the NTNF program, it was recognized that there would be a desire to collect debris samples for analysis as soon as possible after a nuclear event. Based on nuclear test experience, it was recognized that mean radiation fields associated with even low yield events could be several thousand R/Hr near the detonation point for some time after the detonation. In anticipation of pressures to rapidly sample debris near the crater, considerable effort is being devoted to developing a remotely controlled vehicle that could enter the high radiation field area and collect one or more samples for subsequent analysis.

  17. Effective field theory for few-boson systems

    NASA Astrophysics Data System (ADS)

    Bazak, Betzalel; Eliyahu, Moti; van Kolck, Ubirajara

    2016-11-01

    We study universal bosonic few-body systems within the framework of effective field theory at leading order (LO). We calculate binding energies of systems of up to six particles and the atom-dimer scattering length. Convergence to the limit of zero-range two- and three-body interactions is shown, indicating that no additional few-body interactions need to be introduced at LO. Generalizations of the Tjon line are constructed, showing correlations between few-body binding energies and the binding energy of the trimer, for a given dimer energy. As a specific example, we implement our theory for 4He atomic systems and show that the results are in surprisingly good agreement with those of sophisticated 4He-4He potentials. Potential implications for the convergence of the EFT expansion are discussed.

  18. SECURE personnel screening system: field trials and new developments

    NASA Astrophysics Data System (ADS)

    Smith, Steven W.

    1997-01-01

    Many different techniques have been investigated for detecting weapons, explosives, and contraband concealed under a person's clothing. Most of these are based on imaging the concealed object by using some sort of penetrating radiation, such as microwaves, ultrasound or electromagnetic fields.In spite of this effort by dozens of research groups, the only technique that has resulted in a commercially viable product is back-scatter x-ray imaging, as embodied in the SECURE 1000 personnel screening systems. The SECURE technology uses radiation levels that are insignificant compared to natural background values, being viewed as 'trivial' and 'completely insignificant' under established radiation safety standards. In the five years since the SECURE 1000 was developed, more than a dozen field trials and initial placements have been completed. This paper describes both the capabilities and limitations of the technology in these real-world applications.

  19. Temperature field study of hot water circulation pump shaft system

    NASA Astrophysics Data System (ADS)

    Liu, Y. Y.; Kong, F. Y.; Daun, X. H.; Zhao, R. J.; Hu, Q. L.

    2016-05-01

    In the process of engineering application under the condition of hot water circulation pump, problems of stress concentration caused by the temperature rise may happen. In order to study the temperature field in bearing and electric motor chamber of the hot water circulation pump and optimize the structure, in present paper, the model of the shaft system is created through CREO. The model is analyzed by ANSYS workbench, in which the thermal boundary conditions are applied to calculate, which include the calorific values from the bearings, the thermal loss from electric motor and the temperature from the transporting medium. From the result, the finite element model can reflect the distribution of thermal field in hot water circulation pump. Further, the results show that the maximum temperature locates in the bearing chamber.The theoretical guidance for the electric motor heat dissipation design of the hot water circulation pump can be achieved.

  20. Athermalization for infrared dual field-of-view optical system

    NASA Astrophysics Data System (ADS)

    Yang, Changcheng; Li, Shenghui

    2008-03-01

    With the principle of mechanical passive athermalization, a method of making the dual field-of-view (DFOV) switching zoom system for passive athermalization is presented. The long effective focal length (EFL) and short EFL have the same focus shift values of temperature by optical material combination of switching groups. So the long EFL and short EFL of this system achieve the best temperature compensation simultaneously by moving the compensated lens with the same distance, and the system has the best images and parfocality in a large working temperature. A DFOV switching zoom system is designed. It has a relative aperture of f/4.0, 100% cold shield efficiency, the EFL of 180mm/60mm at 3.7-4.8μm. The movement of compensated lens can be achieved with four layers of aluminum/titanium materials. Compared with the MTF of a normal switching zoom system without athermalization, this system needn't move the compensated lens repeatedly to obtain the best images from -30°C to 70°C and enhances the performance of target tracking and recognition.

  1. Advancing the field of health systems research synthesis.

    PubMed

    Langlois, Etienne V; Ranson, Michael K; Bärnighausen, Till; Bosch-Capblanch, Xavier; Daniels, Karen; El-Jardali, Fadi; Ghaffar, Abdul; Grimshaw, Jeremy; Haines, Andy; Lavis, John N; Lewin, Simon; Meng, Qingyue; Oliver, Sandy; Pantoja, Tomás; Straus, Sharon; Shemilt, Ian; Tovey, David; Tugwell, Peter; Waddington, Hugh; Wilson, Mark; Yuan, Beibei; Røttingen, John-Arne

    2015-07-10

    Those planning, managing and working in health systems worldwide routinely need to make decisions regarding strategies to improve health care and promote equity. Systematic reviews of different kinds can be of great help to these decision-makers, providing actionable evidence at every step in the decision-making process. Although there is growing recognition of the importance of systematic reviews to inform both policy decisions and produce guidance for health systems, a number of important methodological and evidence uptake challenges remain and better coordination of existing initiatives is needed. The Alliance for Health Policy and Systems Research, housed within the World Health Organization, convened an Advisory Group on Health Systems Research (HSR) Synthesis to bring together different stakeholders interested in HSR synthesis and its use in decision-making processes. We describe the rationale of the Advisory Group and the six areas of its work and reflects on its role in advancing the field of HSR synthesis. We argue in favour of greater cross-institutional collaborations, as well as capacity strengthening in low- and middle-income countries, to advance the science and practice of health systems research synthesis. We advocate for the integration of quasi-experimental study designs in reviews of effectiveness of health systems intervention and reforms. The Advisory Group also recommends adopting priority-setting approaches for HSR synthesis and increasing the use of findings from systematic reviews in health policy and decision-making.

  2. DEVELOPMENT OF A PRECISE MAGNETIC FIELD MEASUREMENT SYSTEM FOR FAST-CHANGING MAGNETIC FIELDS.

    SciTech Connect

    WANDERER,P.; ESCALLIER,J.; GANETIS,G.; JAIN,A.; LOUIE,W.; MARONE,A.; THOMAS,R.

    2003-06-15

    Several recent applications for fast ramped magnets have been found that require precise measurement of the time-dependent fields. In one instance, accelerator dipoles will be ramped at 1 T/sec, with measurements needed to the typical level of accuracy for accelerators, {Delta} B/B better than 0.01%. To meet this need, we have begun development of a system containing 16 stationary pickup windings that will be sampled at a high rate. It is hoped that harmonics through the decapole can be measured with this system. Precise measurement of the time-dependent harmonics requires that both the pickup windings and the voltmeters be nearly identical. To minimize costs, printed circuit boards are being used for the pickup windings and a combination of amplifiers and ADC's for voltmeters. In addition, new software must be developed for the analysis. The paper will present a status report on this work.

  3. Field experience with a mobile tomographic nondestructive assay system

    SciTech Connect

    Prettyman, T.H.; Betts, S.E.; Taggart, D.P.; Estep, R.J.; Nicholas, N.J.; Lucas, M.C.; Harlan, R.A.

    1995-12-01

    A mobile tomographic gamma-ray scanner (TGS) developed by Los Alamos National Laboratory was recently demonstrated at the Rocky Flats Environmental Technology Site and is currently in use at Los Alamos waste storage areas. The scanner was developed to assay radionuclides in low-level, transuranic, and mixed waste in containers ranging in size from 2 ft{sup 3} boxes to 83-gallon overpacks. The tomographic imaging capability provides a complete correction for source distribution and matrix attenuation effects, enabling accurate assays of Pu-239 and other gamma-ray emitting isotopes. In addition, the system can reliably detect self-absorbing material such as plutonium metal shot, and can correct for bias caused by self-absorption. The system can be quickly configured to execute far-field scans, segmented gamma-ray scans, and a host of intermediate scanning protocols, enabling higher throughput (up to 20 drums per 8-hour shift). In this paper, we will report on the results of field trials of the mobile system at Rocky Flats and Los Alamos. Assay accuracy is confirmed for cases in which TGS assays can be compared with assays (e.g. with calorimetry) of individual packages within the drums. The mobile tomographic technology is expected to considerably reduce characterization costs at DOE production and environmental technology sites.

  4. Field Guide for Designing Human Interaction with Intelligent Systems

    NASA Technical Reports Server (NTRS)

    Malin, Jane T.; Thronesbery, Carroll G.

    1998-01-01

    The characteristics of this Field Guide approach address the problems of designing innovative software to support user tasks. The requirements for novel software are difficult to specify a priori, because there is not sufficient understanding of how the users' tasks should be supported, and there are not obvious pre-existing design solutions. When the design team is in unfamiliar territory, care must be taken to avoid rushing into detailed design, requirements specification, or implementation of the wrong product. The challenge is to get the right design and requirements in an efficient, cost-effective manner. This document's purpose is to describe the methods we are using to design human interactions with intelligent systems which support Space Shuttle flight controllers in the Mission Control Center at NASA/Johnson Space Center. Although these software systems usually have some intelligent features, the design challenges arise primarily from the innovation needed in the software design. While these methods are tailored to our specific context, they should be extensible, and helpful to designers of human interaction with other types of automated systems. We review the unique features of this context so that you can determine how to apply these methods to your project Throughout this Field Guide, goals of the design methods are discussed. This should help designers understand how a specific method might need to be adapted to the project at hand.

  5. Two-level systems driven by large-amplitude fields

    NASA Astrophysics Data System (ADS)

    Nori, F.; Ashhab, S.; Johansson, J. R.; Zagoskin, A. M.

    2009-03-01

    We analyze the dynamics of a two-level system subject to driving by large-amplitude external fields, focusing on the resonance properties in the case of driving around the region of avoided level crossing. In particular, we consider three main questions that characterize resonance dynamics: (1) the resonance condition, (2) the frequency of the resulting oscillations on resonance, and (3) the width of the resonance. We identify the regions of validity of different approximations. In a large region of the parameter space, we use a geometric picture in order to obtain both a simple understanding of the dynamics and quantitative results. The geometric approach is obtained by dividing the evolution into discrete time steps, with each time step described by either a phase shift on the basis states or a coherent mixing process corresponding to a Landau-Zener crossing. We compare the results of the geometric picture with those of a rotating wave approximation. We also comment briefly on the prospects of employing strong driving as a useful tool to manipulate two-level systems. S. Ashhab, J.R. Johansson, A.M. Zagoskin, F. Nori, Two-level systems driven by large-amplitude fields, Phys. Rev. A 75, 063414 (2007). S. Ashhab et al, unpublished.

  6. Three-body systems in pionless effective field theory

    NASA Astrophysics Data System (ADS)

    Vanasse, Jared

    2016-04-01

    Investigations of three-body nuclear systems using pionless effective field theory (EFTπ̸) are reviewed. The history of EFTπ̸ in nd and pd scattering is briefly discussed and emphasis put on the use of strict perturbative techniques. In addition renormalization issues appearing in pd scattering are also presented. Bound state calculations are addressed and new perturbative techniques for describing them are highlighted. Three-body breakup observables in nd scattering are also considered and the utility of EFTπ̸ for addressing them.

  7. Field repair of coated columbium Thermal Protection System (TPS)

    NASA Technical Reports Server (NTRS)

    Culp, J. D.

    1972-01-01

    The requirements for field repair of coated columbian panels were studied, and the probable cause of damage were identified. The following types of repair methods were developed, and are ready for use on an operational system: replacement of fused slurrey silicide coating by a short processing cycle using a focused radiant spot heater; repair of the coating by a glassy matrix ceramic composition which is painted or sprayed over the defective area; and repair of the protective coating by plasma spraying molybdenum disilicide over the damaged area employing portable equipment.

  8. Healing of Chronic Wounds through Systemic Effects of Electromagnetic Fields

    NASA Astrophysics Data System (ADS)

    Cañedo, L.; Trigos, I.; García-Cantú, R.; Godina-Nava, J. J.; Serrano, G.

    2002-08-01

    Extremely low frequency electromagnetic fields (ELF) were configured to interact with peripheral blood mononuclear cells (PBMC). These ELF were applied in the arm to five patients with chronic wounds resistant to medical and surgical treatment. Wound healing began in all patients during the first two weeks after ELF exposure permiting their previously unresponsive chronic wounds to function as internal controls. All lesions were cured or healed >70% in less than four months. Systemic effects were explained by ELF activation of PBMC and their transportation through the blood to the affected site. This therapy is effective in selected patients with chronic wounds.

  9. Delocalization and quantum chaos in atom-field systems.

    PubMed

    Bastarrachea-Magnani, M A; López-del-Carpio, B; Chávez-Carlos, J; Lerma-Hernández, S; Hirsch, J G

    2016-02-01

    Employing efficient diagonalization techniques, we perform a detailed quantitative study of the regular and chaotic regions in phase space in the simplest nonintegrable atom-field system, the Dicke model. A close correlation between the classical Lyapunov exponents and the quantum Participation Ratio of coherent states on the eigenenergy basis is exhibited for different points in the phase space. It is also shown that the Participation Ratio scales linearly with the number of atoms in chaotic regions and with its square root in the regular ones.

  10. Cobra sealing system; From field evaluation to practical safeguards application

    SciTech Connect

    Vodrazka, P.; Cermak, L. )

    1991-01-01

    After a successful conclusion of the Cobra seal IAEA field trials, the Cobra Seal System was installed in two Canadian facilities. The seals permit on-site verification without needing to replace them in extreme weather conditions, thus allowing a substantial time reduction for inspectors as well as minimizing intrusiveness of these activities. The paper describes experiences with practical installations of almost sixty Cobra seals including the selection of environmental conduits and housing. Examples of the results of the first several inspections utilizing a new version of the Cobra seal verifier are also included. Possible future outdoor applications of Cobra seals are described and some suggested improvements are outlined.

  11. Field experiments using SPEAR: a speech control system for UGVs

    NASA Astrophysics Data System (ADS)

    Chhatpar, Siddharth R.; Blanco, Chris; Czerniak, Jeffrey; Hoffman, Orin; Juneja, Amit; Pruthi, Tarun; Liu, Dongqing; Karlsen, Robert; Brown, Jonathan

    2009-05-01

    This paper reports on a Field Experiment carried out by the Human Research and Engineering Directorate at Ft. Benning to evaluate the efficacy of using speech to control an Unmanned Ground Vehicle (UGV) concurrently with a handcontroller. The SPEAR system, developed by Think-A-Move, provides speech-control of UGVs. The system picks up user-speech in the ear canal with an in-ear microphone. This property allows it to work efficiently in high-noise environments, where traditional speech systems, employing external microphones, fail. It has been integrated with an iRobot PackBot 510 with EOD kit. The integrated system allows the hand-controller to be supplemented with speech for concurrent control. At Ft. Benning, the integrated system was tested by soldiers from the Officer Candidate School. The Experiment had dual focus: 1) Quantitative measurement of the time taken to complete each station and the cognitive load on users; 2) Qualitative evaluation of ease-of-use and ergonomics through soldier-feedback. Also of significant benefit to Think-A-Move was soldier-feedback on the speech-command vocabulary employed: What spoken commands are intuitive, and how the commands should be executed, e.g., limited-motion vs. unlimited-motion commands. Overall results from the Experiment are reported in the paper.

  12. Dimensioning IRGA gas sampling systems: laboratory and field experiments

    NASA Astrophysics Data System (ADS)

    Aubinet, Marc; Joly, Lilian; Loustau, Denis; De Ligne, Anne; Chopin, Henri; Cousin, Julien; Chauvin, Nicolas; Decarpenterie, Thomas; Gross, Patrick

    2016-03-01

    Both laboratory and field experiments were carried out in order to define suitable configuration ranges for the gas sampling systems (GSSs) of infrared gas analyzers (IRGAs) used in eddy covariance measurements.

    In the laboratory, an original dynamic calibration bench was developed in order to test the frequency attenuation and pressure drop generated by filters. In the field, three IRGAs of the same type equipped with different filters or different rain caps were installed and run and the real frequency response of the complete setup was tested. The main results are as follows. - Filters may have a strong impact on the pressure drop in the GSS and this impact increases with flow rate. - Conversely, no impact of the tested filters on cut-off frequency was found, GSSs with and without filters presenting similar cut-off frequencies. - The main limiting factor of cut-off frequency in the field was found to be the rain cap design. In addition, the impact of this design on pressure drop was also found to be noteworthy.

  13. Dimensioning IRGA gas sampling system : laboratory and field experiments

    NASA Astrophysics Data System (ADS)

    Aubinet, Marc; Joly, Lilian; Loustau, Denis; De Ligne, Anne; Chopin, Henri; Cousin, Julien; De Carpenterie, Thomas; Gross, Patrick; Chauvin, Nicolas

    2016-04-01

    Both laboratory and field experiments were carried out in order to define suitable configuration ranges for the gas sampling systems (GSS) of infrared gas analyzers (IRGA) used in eddy covariance measurements. In the laboratory, an original dynamic calibration bench was developed in order to test the frequency attenuation and pressure drop generated by filters. In the field, three IRGAs of the same type equipped with different filters or different rain caps were installed and run and the real frequency response of the complete set-up was tested. The main results are that: - Filters may have a strong impact on the pressure drop in the GSS and this impact increases with flow rate. - On the contrary, no impact of the tested filters on cut off frequency was found, GSS with and without filters presenting similar cut off frequencies. - The main limiting factor of cut off frequency in the field was found to be the rain cap design. In addition, the impact of this design on pressure drop was also found noteworthy.

  14. Massless scalar field and solar-system experiments

    SciTech Connect

    Formiga, J. B.

    2011-04-15

    The solution of Einstein's field equations with the energy-momentum tensor of a massless scalar field is known as the Fisher solution. It is well known that this solution has a naked singularity due to the ''charge''{Sigma} of the massless scalar field. Here I obtain the radial null geodesic of the Fisher solution and use it to confirm that there is no black hole. In addition, I use the parametrized post-Newtonian formalism to show that the Fisher spacetime predicts the same effects on solar-system experiments as the Schwarzschild one does, as long as we impose a limit on {Sigma}. I show that this limit is not a strong constraint and we can even take values of {Sigma} bigger than M. By using the exact formula of the redshift and some assumptions, I evaluate this limit for the experiment of Pound and Snider [Phys. Rev. 140, B788 (1965)]. It turns out that this limit is {Sigma}<5.8x10{sup 3} m.

  15. 4D Light Field Imaging System Using Programmable Aperture

    NASA Technical Reports Server (NTRS)

    Bae, Youngsam

    2012-01-01

    Complete depth information can be extracted from analyzing all angles of light rays emanated from a source. However, this angular information is lost in a typical 2D imaging system. In order to record this information, a standard stereo imaging system uses two cameras to obtain information from two view angles. Sometimes, more cameras are used to obtain information from more angles. However, a 4D light field imaging technique can achieve this multiple-camera effect through a single-lens camera. Two methods are available for this: one using a microlens array, and the other using a moving aperture. The moving-aperture method can obtain more complete stereo information. The existing literature suggests a modified liquid crystal panel [LC (liquid crystal) panel, similar to ones commonly used in the display industry] to achieve a moving aperture. However, LC panels cannot withstand harsh environments and are not qualified for spaceflight. In this regard, different hardware is proposed for the moving aperture. A digital micromirror device (DMD) will replace the liquid crystal. This will be qualified for harsh environments for the 4D light field imaging. This will enable an imager to record near-complete stereo information. The approach to building a proof-ofconcept is using existing, or slightly modified, off-the-shelf components. An SLR (single-lens reflex) lens system, which typically has a large aperture for fast imaging, will be modified. The lens system will be arranged so that DMD can be integrated. The shape of aperture will be programmed for single-viewpoint imaging, multiple-viewpoint imaging, and coded aperture imaging. The novelty lies in using a DMD instead of a LC panel to move the apertures for 4D light field imaging. The DMD uses reflecting mirrors, so any light transmission lost (which would be expected from the LC panel) will be minimal. Also, the MEMS-based DMD can withstand higher temperature and pressure fluctuation than a LC panel can. Robotics need

  16. FINESSE: Field Investigations to Enable Solar System Science and Exploration

    NASA Technical Reports Server (NTRS)

    Heldmann, Jennifer; Lim, Darlene; Colaprete, Anthony

    2015-01-01

    The FINESSE (Field Investigations to Enable Solar System Science and Exploration) team is focused on a science and exploration field-based research program aimed at generating strategic knowledge in preparation for the human and robotic exploration of the Moon, near-Earth asteroids (NEAs) and Phobos and Deimos. We follow the philosophy that "science enables exploration and exploration enables science." 1) FINESSE Science: Understand the effects of volcanism and impacts as dominant planetary processes on the Moon, NEAs, and Phobos & Deimos. 2) FINESSE Exploration: Understand which exploration concepts of operations (ConOps) and capabilities enable and enhance scientific return. To accomplish these objectives, we are conducting an integrated research program focused on scientifically-driven field exploration at Craters of the Moon National Monument and Preserve in Idaho and at the West Clearwater Lake Impact Structure in northern Canada. Field deployments aimed at reconnaissance geology and data acquisition were conducted in 2014 at Craters of the Moon National Monument and Preserve. Targets for data acquisition included selected sites at Kings Bowl eruptive fissure, lava field and blowout crater, Inferno Chasm vent and outflow channel, North Crater lava flow and Highway lava flow. Field investigation included (1) differential GPS (dGPS) measurements of lava flows, channels (and ejecta block at Kings Bowl); (2) LiDAR imaging of lava flow margins, surfaces and other selected features; (3) digital photographic documentation; (4) sampling for geochemical and petrographic analysis; (5) UAV aerial imagery of Kings Bowl and Inferno Chasm features; and (6) geologic assessment of targets and potential new targets. Over the course of the 5-week field FINESSE campaign to the West Clearwater Impact Structure (WCIS) in 2014, the team focused on several WCIS research topics, including impactites, central uplift formation, the impact-generated hydrothermal system, multichronometer

  17. Three-dimensional forward calculation of the electromagnetic fields induced by tsunamis

    NASA Astrophysics Data System (ADS)

    Utada, H.; Zhang, L.; Shimizu, H.; Baba, K.; Maeda, T.

    2012-12-01

    The motion of seawater induces electromotive force of significant intensity (Sanford, 1971) due to Faraday's law, and resulting electromagnetic (EM) field can be recorded by instruments installed on land or at ocean bottom (Tyler, 2005; Toh et al. 2011). However, only a few studies were successfully simulating Tsunami induced EM fields by an exact and accurate application of Maxwell equations that is essential for a quantitative interpretation to get geophysical information from observations of tsunami-related EM signals. There are a number of observations of such EM fields that were caused by the devastating Tohoku tsunami of 2011 not only on land observatories but also at some seafloor sites (e.g. Utada et al., 2011; Ichihara et al., 2012). Here we present a 3-D modeling scheme to simulate these observed fields. We apply a 3-D EM induction code in Cartesian coordinate system with the heterogeneous source term, which is based on the modified iterative dissipative method (MIDM) (Zhang et al. 2012), and several underground electrical conductivity structures were assumed in the calculations. The source current distribution is predicted by the flow data calculated by a tsunami simulation (Maeda and Furumura, 2011) which solves Navier-Stokes equations in 3-D Cartesian coordinates. In our previous study (Utada et al., 2011), we estimated tsunami-induced fields by applying Biot-Savart law to the same set of flow data and obtained qualitative agreement between observations on land and model results. However quantitatively, we noticed that the present result generally gives smaller amplitude than the result of Biot-Savart calculation. This can be ascribed to the EM induction effect in the sea. We also tried some underground structures, but the effect of the underground structure is negligible compared with that of the induction in the sea. Meanwhile, we found that the effect of the source current by the vertical motion, which was ignored in the previous study, can be

  18. Evaluation of PCR Systems for Field Screening of Bacillus anthracis

    PubMed Central

    Ozanich, Richard M.; Colburn, Heather A.; Victry, Kristin D.; Bartholomew, Rachel A.; Arce, Jennifer S.; Heredia-Langner, Alejandro; Jarman, Kristin; Kreuzer, Helen W.

    2017-01-01

    There is little published data on the performance of hand-portable polymerase chain reaction (PCR) systems that can be used by first responders to determine if a suspicious powder contains a potential biothreat agent. We evaluated 5 commercially available hand-portable PCR instruments for detection of Bacillus anthracis. We used a cost-effective, statistically based test plan to evaluate systems at performance levels ranging from 0.85-0.95 lower confidence bound (LCB) of the probability of detection (POD) at confidence levels of 80% to 95%. We assessed specificity using purified genomic DNA from 13 B. anthracis strains and 18 Bacillus near neighbors, potential interference with 22 suspicious powders that are commonly encountered in the field by first responders during suspected biothreat incidents, and the potential for PCR inhibition when B. anthracis spores were spiked into these powders. Our results indicate that 3 of the 5 systems achieved 0.95 LCB of the probability of detection with 95% confidence levels at test concentrations of 2,000 genome equivalents/mL (GE/mL), which is comparable to 2,000 spores/mL. This is more than sufficient sensitivity for screening visible suspicious powders. These systems exhibited no false-positive results or PCR inhibition with common suspicious powders and reliably detected B. anthracis spores spiked into these powders, though some issues with assay controls were observed. Our testing approach enables efficient performance testing using a statistically rigorous and cost-effective test plan to generate performance data that allow users to make informed decisions regarding the purchase and use of field biodetection equipment. PMID:28192050

  19. Physical characteristics of a full-field digital mammography system

    NASA Astrophysics Data System (ADS)

    Suryanarayanan, Sankararaman; Karellas, Andrew; Vedantham, Srinivasan

    2004-11-01

    The physical performance characteristics of a flat-panel clinical full-field digital mammography (FFDM) system were investigated for a variety of mammographic X-ray spectral conditions. The system was investigated using 26 kVp: Mo/Mo, 28 kVp: Mo/Rh, and 30 kVp: Rh/Rh, with polymethyl methacrylate (PMMA) "tissue equivalent material" of thickness 20, 45, and 60 mm for each of three X-ray spectra, resulting in nine different spectral conditions. The experimental results were compared with a theoretical cascaded linear systems-based model that has been developed independently by other investigators. The FFDM imager (Senographe 2000D, GE Medical Systems, Milwaukee, WI) uses an amorphous silicon (aSi:H) photodiode (100 μm pixel) array directly coupled to a cesium iodide (CsI) scintillator. The spatial resolution of the digital mammography system was determined by measuring the presampling modulation transfer function (MTF). The noise power spectra (NPS) of the system were measured under the different mammographic X-ray spectral conditions at an exposure of approximately 10 mR to the detector from which corresponding detective quantum efficiencies (DQE) were determined. The experimental results provide additional information on the performance of the mammographic system for a broader range of experimental conditions than have been reported in the past. The flat-panel imager exhibits favorable physical quality characteristics under the conditions investigated. The experimental results were compared with theoretical estimates under various spectral conditions and demonstrated good agreement.

  20. Smart Infrared Inspection System Field Operational Test Final Report

    SciTech Connect

    Siekmann, Adam; Capps, Gary J; Franzese, Oscar; Lascurain, Mary Beth

    2011-06-01

    The Smart InfraRed Inspection System (SIRIS) is a tool designed to assist inspectors in determining which vehicles passing through the SIRIS system are in need of further inspection by measuring the thermal data from the wheel components. As a vehicle enters the system, infrared cameras on the road measure temperatures of the brakes, tires, and wheel bearings on both wheel ends of commercial motor vehicles (CMVs) in motion. This thermal data is then presented to enforcement personal inside of the inspection station on a user friendly interface. Vehicles that are suspected to have a violation are automatically alerted to the enforcement staff. The main goal of the SIRIS field operational test (FOT) was to collect data to evaluate the performance of the prototype system and determine the viability of such a system being used for commercial motor vehicle enforcement. From March 2010 to September 2010, ORNL facilitated the SIRIS FOT at the Greene County Inspection Station (IS) in Greeneville, Tennessee. During the course of the FOT, 413 CMVs were given a North American Standard (NAS) Level-1 inspection. Of those 413 CMVs, 384 were subjected to a SIRIS screening. A total of 36 (9.38%) of the vehicles were flagged by SIRIS as having one or more thermal issues; with brakes issues making up 33 (91.67%) of those. Of the 36 vehicles flagged as having thermal issues, 31 (86.11%) were found to have a violation and 30 (83.33%) of those vehicles were placed out-of-service (OOS). Overall the enforcement personnel who have used SIRIS for screening purposes have had positive feedback on the potential of SIRIS. With improvements in detection algorithms and stability, the system will be beneficial to the CMV enforcement community and increase overall trooper productivity by accurately identifying a higher percentage of CMVs to be placed OOS with minimal error. No future evaluation of SIRIS has been deemed necessary and specifications for a production system will soon be drafted.

  1. Nonlinear phase field model for electrodeposition in electrochemical systems

    SciTech Connect

    Liang, Linyun; Chen, Long-Qing

    2014-12-29

    A nonlinear phase-field model has been developed for describing the electrodeposition process in electrochemical systems that are highly out of equilibrium. Main thermodynamic driving forces for the electrode-electrolyte interface (EEI) evolution are limited to local variations of overpotential and ion concentration. Application of the model to Li-ion batteries describes the electrode interface motion and morphology change caused by charge mass transfer in the electrolyte, an electrochemical reaction at the EEI and cation deposition on the electrode surface during the charging operation. The Li electrodeposition rate follows the classical Butler-Volmer kinetics with exponentially and linearly depending on local overpotential and cation concentration at the electrode surface, respectively. Simulation results show that the Li deposit forms a fiber-like shape and grows parallel to the electric field direction. The longer and thicker deposits are observed both for higher current density and larger rate constant where the surface reaction rate is expected to be high. The proposed diffuse interface model well captures the metal electrodeposition phenomena in plenty of non-equilibrium electrochemical systems.

  2. Mantle flow field in the southern Ryukyu subduction system

    NASA Astrophysics Data System (ADS)

    Lin, S.; Kuo, B.

    2012-12-01

    The Okinawa trough in the Ryukyu subduction system is the only active back arc basin formed within a continental lithosphere. Recent shear-wave splitting measurements show variable fast directions along the trough suggesting complex three-dimensional flow field in the mantle wedge. In this study we use numerical subduction models to explore the effects of plate thickness variations caused by non-uniform lithospheric stretching on the dynamics in the southern Ryukyu subduction system. We calculate orientations of infinite strain axes as a proxy for olivine lattice preferred orientations and orientations of seismic anisotropy. Our models demonstrate that flow patterns may vary significantly with depth near the plate edge as a result of the along-arc variations in lithospheric thickness. The model results show that the toroidal circulation around the lateral slab edge predominates at greater depths. The thick neighboring lithosphere acts as an effective barrier of the lateral mass exchanges in the shallow portion of the mantle wedge. The wedge material is drawn in horizontally toward the plate edge from the central region of the subduction zone induced by pressure gradients, opposite to the inwards lateral flow at greater depths. Model predictions for the lattice preferred orientations of olivine aggregates agree reasonably well with the observed shear-wave splitting patterns. The results suggest that the depth-varying flow field near the subduction zone edge and the westward flow components in the shallow portion of the mantle wedge may contribute to complex patterns of seismic anisotropy and arc isotopic systematics.

  3. Scientific investigation plan for initial engineered barrier system field tests

    SciTech Connect

    Wunan Lin

    1993-02-01

    The purpose of this Scientific Investigation Plan (SIP) is to describe tests known as Initial Engineered Barrier System Field Tests (IEBSFT) and identified by Work Breakdown Structure as WBS 1.2.2.2.4. The IEBSFT are precursors to the Engineered Barrier System Field Test (EBSFT), WBS 1.2.2.2.4, to be conducted in the Exploratory Study Facility (ESF) at Yucca Mountain. The EBSFT and IEBSFT are designed to provide information on the interaction between waste packages (simulated by heated containers) and the surrounding rock mass, its vadose water, and infiltrated water. Heater assemblies will be installed in drifts or boreholes openings and heated to measure moisture movement during heat-up and subsequent cool-down of the rock mass. In some of the tests, infiltration of water into the heated rock mass will be studied. Throughout the heating and cooling cycle, instruments installed in the rock will monitor such parameters as temperature, moisture content, concentration of some chemical species, and stress and strain. Rock permeability measurements, rock and fluid (water and gas) sampling, and fracture pattern measurements will also be made before and after the test.

  4. An Oceanographic Decision Support System for Scientific Field Experiments

    NASA Astrophysics Data System (ADS)

    Maughan, T.; Das, J.; McCann, M. P.; Rajan, K.

    2011-12-01

    Thom Maughan, Jnaneshwar Das, Mike McCann, Danelle Cline, Mike Godin, Fred Bahr, Kevin Gomes, Tom O'Reilly, Frederic Py, Monique Messie, John Ryan, Francisco Chavez, Jim Bellingham, Maria Fox, Kanna Rajan Monterey Bay Aquarium Research Institute Moss Lading, California, United States Many of the coastal ocean processes we wish to observe in order to characterize marine ecosystems have large spatial extant (tens of square km) and are dynamic moving kilometers in a day with biological processes spanning anywhere from minutes to days. Some like harmful algal blooms generate toxins which can significantly impact human health and coastal economies. In order to obtain a viable understanding of the biogeochemical processes which define their dynamics and ecology, it is necessary to persistently observe, track and sample within and near the dynamic fields using augmented methods of observation such as autonomous platforms like AUVs, gliders and surface craft. Field experiments to plan, execute and manage such multitude of assets are challenging. To alleviate this problem the autonomous systems group with its collaborators at MBARI and USC designed, built and fielded a prototype Oceanographic Decision Support System (ODSS) that provides situational awareness and a single portal to visualize and plan deployments for the large scale October 2010 CANON field program as well as a series of 2 week field programs in 2011. The field programs were conducted in Monterey Bay, a known 'red tide' incubator, and varied from as many as twenty autonomous platforms, four ships and 2 manned airplanes to coordinated AUV operations, drifters and a single ship. The ODSS web-based portal was used to assimilate information from a collection of sources at sea, including AUVs, moorings, radar data as well as remote sensing products generated by partner organizations to provide a synthesis of views useful to predict the movement of a chlorophyll patch in the confines of the northern Monterey Bay

  5. Near-Field Based Communication and Electrical Systems

    NASA Astrophysics Data System (ADS)

    Azad, Umar

    A near-field power transfer equation for an inductively coupled near-field system is derived based on the equivalent circuit model of the coupled resonant loops. Experimental results show that the proposed near-field coupling equation is trustworthy as it correctly predicts the transferred power versus distance relationship for different values of loaded quality factors at the transmitter and the receiver. Capacity performance of near-field communication (NFC) links is analyzed for noise limited and interference limited scenarios based on information theory. The analytical results provide guidelines for design of inductively coupled antenna systems as the power and capacity budget of the link is carried out. Examples of inductively coupled VLF NFC links are evaluated for different operating scenarios, demonstrating the efficacy and importance of the proposed near-field link budget. However, in a conventional setup of inductively coupled NFC link, the power coupled through and the bandwidth must be traded off. Direct Antenna Modulation (DAM) is a feasible scheme to break this dilemma. With DAM utilized in NFC link, the power and bandwidth product limit in a high Q system can be circumvented because the non-linear/time-varying nature of the operation allows high speed modulations decoupled from the charging and discharging process of the high-Q resonator. In this work, the theory of NFC link with DAM on the transmitter is presented and validated with an experimental setup. Improvement in reception of the high-speed modulation information is observed in the experiment, implying that a superior capacity performance of a NFC link is achieved through DAM versus the traditional scheme. The resonant coupling efficiency is limited by the product of the quality factors Q, of the transmitter and receiver and the coupling coefficient k. We observe that in order to achieve maximum efficiency, the ratio of the load-to-loss impedances at both the source and load should be equal

  6. Rotating dipole and quadrupole field for a multiple cathode system

    SciTech Connect

    Chang, X.; Ben-Zvi, I.; Kewisch, J.; Litvinenko, V.; Meng, W.; Pikin, A.; Ptitsyn, V.; Rao, T.; Sheehy, B.; Skarita, J.; Wang, E.; Wu, Q.; Xin, T.

    2011-03-28

    A multiple cathode system has been designed to provide the high average current polarized electron bunches for the future electron-ion collider eRHIC [1]. One of the key research topics in this design is the technique to generate a combined dipole and quadrupole rotating field at high frequency (700 kHz). This type of field is necessary for combining bunches from different cathodes to the same axis with minimum emittance growth. Our simulations and the prototype test results to achieve this will be presented. The future eRHIC project, next upgrade of EHIC, will be the first electron-heavy ion collider in the world. For polarized-electron and polarized proton collisions, it requires a polarized electron source with high average current ({approx}50 mA), short bunch ({approx}3 mm), emittance of about 20 {micro}m and energy spread of {approx}1% at 10 MeV. The state-of-art polarized electron cathode can generate average current of about more than 1 mA, but much less than 50 mA. The current is limited by the quantum efficiency, lifetime, space charge and ultra-high vacuum requirement of the polarized cathode. A possible approach to achieve the 50 mA beam is to employ multiple cathodes, such as 20 cathodes, and combine the multiple bunched beams from cathodes to the same axis. We name it as 'Gatling gun' because its operations bear similarity to a multi-barrel Gatling gun. The electron spin direction is not affected by electric field but will follow to the direction of the magnetic bending. This requires that, to preserve the spin polarization from cathode, the fixed bending field after the solenoid and the rotating bending field in combiner must be either a pair of electric bendings or a pair of magnetic bendings. We choose the scheme with a pair of magnetic bendings because it is much easier than the scheme with a pair of electric bendings at our 200 keV electron energy level.

  7. Note: Upgrade of electron cyclotron emission imaging system and preliminary results on HL-2A tokamak

    SciTech Connect

    Jiang, M. Shi, Z. B.; Zhong, W. L.; Chen, W.; Liu, Z. T.; Ding, X. T.; Yang, Q. W.; Zhang, B. Y.; Shi, P. W.; Liu, Y.; Fu, B. Z.; Xu, Y.; Domier, C. W.; Luhmann, N. C.; Yang, Z. C.

    2015-07-15

    The electron cyclotron emission imaging system on the HL-2A tokamak has been upgraded to 24 (poloidally) × 16 (radially) channels based on the previous 24 × 8 array. The measurement region can be flexibly shifted due to the independence of the two local oscillator sources, and the field of view can be adjusted easily by changing the position of the zoom lenses. The temporal resolution is about 2.5 μs and the achievable spatial resolution is 1 cm. After laboratory calibration, it was installed on HL-2A tokamak in 2014, and the local 2D mode structures of MHD activities were obtained for the first time.

  8. Note: Upgrade of electron cyclotron emission imaging system and preliminary results on HL-2A tokamak.

    PubMed

    Jiang, M; Shi, Z B; Domier, C W; Luhmann, N C; Zhong, W L; Chen, W; Liu, Z T; Ding, X T; Yang, Q W; Zhang, B Y; Yang, Z C; Shi, P W; Liu, Y; Fu, B Z; Xu, Y

    2015-07-01

    The electron cyclotron emission imaging system on the HL-2A tokamak has been upgraded to 24 (poloidally) × 16 (radially) channels based on the previous 24 × 8 array. The measurement region can be flexibly shifted due to the independence of the two local oscillator sources, and the field of view can be adjusted easily by changing the position of the zoom lenses. The temporal resolution is about 2.5 μs and the achievable spatial resolution is 1 cm. After laboratory calibration, it was installed on HL-2A tokamak in 2014, and the local 2D mode structures of MHD activities were obtained for the first time.

  9. Reducing field distortion for galvanometer scanning system using a vision system

    NASA Astrophysics Data System (ADS)

    Ortega Delgado, Moises Alberto; Lasagni, Andrés Fabián

    2016-11-01

    Laser galvanometer scanning systems are well-established devices for material processing, medical imaging and laser projection. Besides all the advantages of these devices like high resolution, repeatability and processing velocity, they are always affected by field distortions. Different pre-compensating techniques using iterative marking and measuring methods are applied in order to reduce such field distortions and increase in some extends the accuracy of the scanning systems. High-tech devices, temperature control systems and self-adjusting galvanometers are some expensive possibilities for reducing these deviations. This contribution presents a method for reducing field distortions using a coaxially coupled vision device and a self-designed calibration plate; this avoids, among others, the necessity of repetitive marking and measuring phases.

  10. Keldysh field theory for driven open quantum systems.

    PubMed

    Sieberer, L M; Buchhold, M; Diehl, S

    2016-09-01

    Recent experimental developments in diverse areas-ranging from cold atomic gases to light-driven semiconductors to microcavity arrays-move systems into the focus which are located on the interface of quantum optics, many-body physics and statistical mechanics. They share in common that coherent and driven-dissipative quantum dynamics occur on an equal footing, creating genuine non-equilibrium scenarios without immediate counterpart in equilibrium condensed matter physics. This concerns both their non-thermal stationary states and their many-body time evolution. It is a challenge to theory to identify novel instances of universal emergent macroscopic phenomena, which are tied unambiguously and in an observable way to the microscopic drive conditions. In this review, we discuss some recent results in this direction. Moreover, we provide a systematic introduction to the open system Keldysh functional integral approach, which is the proper technical tool to accomplish a merger of quantum optics and many-body physics, and leverages the power of modern quantum field theory to driven open quantum systems.

  11. A review on Electromagnetic fields (EMFs) and the reproductive system.

    PubMed

    Asghari, Ali; Khaki, Amir Afshin; Rajabzadeh, Asghar; Khaki, Arash

    2016-07-01

    Environmental factors, such as electromagnetic waves, induce biological and genetic effects. One of the most important physiological systems involved with electromagnetic fields (EMFs) is the genital system. This paper reviews the effects of EMFs on human reproductive organs, female animals, fetus development and the importance of two types of natural antioxidants, i.e., vitamin E and fennel. The studies presented in this review referred to the effects of different exposures to EMFs on the reproductive system, and we tried to show the role of natural antioxidants in reducing the effects of the exposures. Many studies have been done on the effects of ionizing and non-ionizing electromagnetic waves on the cell line of spermatogenesis, sexual hormones, and the structure of the testes. Also, about the hormonal cycle, folliculogenesis and female infertility related to EMF have been given more consideration. In particular, attention is directed to pregnant women due to the importance of their fetuses. However, in addition to the studies conducted on animals, further epidemiological research should be conducted.

  12. Ultra-low field MRI food inspection system prototype

    NASA Astrophysics Data System (ADS)

    Kawagoe, Satoshi; Toyota, Hirotomo; Hatta, Junichi; Ariyoshi, Seiichiro; Tanaka, Saburo

    2016-11-01

    We develop an ultra-low field (ULF) magnetic resonance imaging (MRI) system using a high-temperature superconducting quantum interference device (HTS-SQUID) for food inspection. A two-dimensional (2D)-MR image is reconstructed from the grid processing raw data using the 2D fast Fourier transform method. In a previous study, we combined an LC resonator with the ULF-MRI system to improve the detection area of the HTS-SQUID. The sensitivity was improved, but since the experiments were performed in a semi-open magnetically shielded room (MSR), external noise was a problem. In this study, we develop a compact magnetically shielded box (CMSB), which has a small open window for transfer of a pre-polarized sample. Experiments were performed in the CMSB and 2D-MR images were compared with images taken in the semi-open MSR. A clear image of a disk-shaped water sample is obtained, with an outer dimension closer to that of the real sample than in the image taken in the semi-open MSR. Furthermore, the 2D-MR image of a multiple cell water sample is clearly reconstructed. These results show the applicability of the ULF-MRI system in food inspection.

  13. Keldysh field theory for driven open quantum systems

    NASA Astrophysics Data System (ADS)

    Sieberer, L. M.; Buchhold, M.; Diehl, S.

    2016-09-01

    Recent experimental developments in diverse areas—ranging from cold atomic gases to light-driven semiconductors to microcavity arrays—move systems into the focus which are located on the interface of quantum optics, many-body physics and statistical mechanics. They share in common that coherent and driven-dissipative quantum dynamics occur on an equal footing, creating genuine non-equilibrium scenarios without immediate counterpart in equilibrium condensed matter physics. This concerns both their non-thermal stationary states and their many-body time evolution. It is a challenge to theory to identify novel instances of universal emergent macroscopic phenomena, which are tied unambiguously and in an observable way to the microscopic drive conditions. In this review, we discuss some recent results in this direction. Moreover, we provide a systematic introduction to the open system Keldysh functional integral approach, which is the proper technical tool to accomplish a merger of quantum optics and many-body physics, and leverages the power of modern quantum field theory to driven open quantum systems.

  14. A review on Electromagnetic fields (EMFs) and the reproductive system

    PubMed Central

    Asghari, Ali; Khaki, Amir Afshin; Rajabzadeh, Asghar; Khaki, Arash

    2016-01-01

    Environmental factors, such as electromagnetic waves, induce biological and genetic effects. One of the most important physiological systems involved with electromagnetic fields (EMFs) is the genital system. This paper reviews the effects of EMFs on human reproductive organs, female animals, fetus development and the importance of two types of natural antioxidants, i.e., vitamin E and fennel. The studies presented in this review referred to the effects of different exposures to EMFs on the reproductive system, and we tried to show the role of natural antioxidants in reducing the effects of the exposures. Many studies have been done on the effects of ionizing and non-ionizing electromagnetic waves on the cell line of spermatogenesis, sexual hormones, and the structure of the testes. Also, about the hormonal cycle, folliculogenesis and female infertility related to EMF have been given more consideration. In particular, attention is directed to pregnant women due to the importance of their fetuses. However, in addition to the studies conducted on animals, further epidemiological research should be conducted. PMID:27648194

  15. Radio-frequency electromagnetic field measurements for direct detection of electron Bernstein waves in a torus plasma

    SciTech Connect

    Yatsuka, Eiichi; Kinjo, Kiyotake; Morikawa, Junji; Ogawa, Yuichi

    2009-02-15

    To identify the mode-converted electron Bernstein wave (EBW) in a torus plasma directly, we have developed an interferometry system, in which a diagnostic microwave injected outside of the plasma column was directly detected with the probing antenna inserted into the plasma. In this work, plasma production and heating are achieved with 2.45 GHz, 2.5 kW electron cyclotron heating (ECH), whereas diagnostics are carried out with a lower power (10 W) separate frequency (1-2.1 GHz) microwave. Three components, i.e., two electromagnetic (toroidal and poloidal directions) and an electrostatic (if refractive index is sufficiently higher than unity, it corresponds to radial component), of ECRF electric field are simultaneously measured with three probing antennas, which are inserted into plasma. Selectivities of each component signal were checked experimentally. Excitation antennas have quite high selectivity of direction of linear polarization. As probing antennas for detecting electromagnetic components, we employed a monopole antenna with a length of 35 mm, and the separation of the poloidal (O-wave) and toroidal (X-wave) components of ECRF electric field could be available with this antenna. To detect EBW, which is an electrostatic wave, a small tip (1 mm) antenna was used. As the preliminary results, we detected signals that have three characteristics of EBW, i.e., short wavelength, backward propagation, and electrostatic.

  16. Radio-frequency electromagnetic field measurements for direct detection of electron Bernstein waves in a torus plasma.

    PubMed

    Yatsuka, Eiichi; Kinjo, Kiyotake; Morikawa, Junji; Ogawa, Yuichi

    2009-02-01

    To identify the mode-converted electron Bernstein wave (EBW) in a torus plasma directly, we have developed an interferometry system, in which a diagnostic microwave injected outside of the plasma column was directly detected with the probing antenna inserted into the plasma. In this work, plasma production and heating are achieved with 2.45 GHz, 2.5 kW electron cyclotron heating (ECH), whereas diagnostics are carried out with a lower power (10 W) separate frequency (1-2.1 GHz) microwave. Three components, i.e., two electromagnetic (toroidal and poloidal directions) and an electrostatic (if refractive index is sufficiently higher than unity, it corresponds to radial component), of ECRF electric field are simultaneously measured with three probing antennas, which are inserted into plasma. Selectivities of each component signal were checked experimentally. Excitation antennas have quite high selectivity of direction of linear polarization. As probing antennas for detecting electromagnetic components, we employed a monopole antenna with a length of 35 mm, and the separation of the poloidal (O-wave) and toroidal (X-wave) components of ECRF electric field could be available with this antenna. To detect EBW, which is an electrostatic wave, a small tip (1 mm) antenna was used. As the preliminary results, we detected signals that have three characteristics of EBW, i.e., short wavelength, backward propagation, and electrostatic.

  17. The ultrasound fields estimation using uncooled infrared system

    NASA Astrophysics Data System (ADS)

    Ying, Yu; Guofeng, Shen; Jingfeng, Bai; Yazhu, Chen

    2012-10-01

    The ultrasound fields through a certain thickness of tissue are a critical parameter in the high intensity focused ultrasound (HIFU) treatment. Although the ultrasonic fields in tissue are difficult to measure, the temperature elevation induced by ultrasound can be obtained to estimate the ultrasonic intensity. In this work, the ex-vivo experiments were conducted in porcine muscle with the thickness of 10-30 mm. The distance from the transducer to the surface of muscle can be varied. The temperature distribution in tissue-air surface can be obtained from an uncooled infrared system (spatial and thermal resolutions are 0.59 mm and 0.08 °C). According the Snell's law, the intensity at interface is about four times of the incident wave when ultrasound wave propagates from tissue to air, due to the total internal reflection. Then the intensity distribution of incident wave can be estimated by temperature distribution in tissue-air surface. The experimental temperature was consistent with that of simulations. The maximum temperature in the surface was 46.27 °C heated for 5s, and the maximum estimated peak incident sound intensity was 458.2 W/cm2. This work may offer implications and information for treatment planning toward optimizing focused ultrasound surgery in deep tumor.

  18. The Receiver System for the Ooty Wide Field Array

    NASA Astrophysics Data System (ADS)

    Subrahmanya, C. R.; Prasad, P.; Girish, B. S.; Somashekar, R.; Manoharan, P. K.; Mittal, A. K.

    2017-03-01

    The legacy Ooty Radio Telescope (ORT) is being reconfigured as a 264-element synthesis telescope, called the Ooty Wide Field Array (OWFA). Its antenna elements are the contiguous 1.92 m sections of the parabolic cylinder. It will operate in a 38-MHz frequency band centred at 326.5 MHz and will be equipped with a digital receiver including a 264-element spectral correlator with a spectral resolution of 48 kHz. OWFA is designed to retain the benefits of equatorial mount, continuous 9-hour tracking ability and large collecting area of the legacy telescope and use of modern digital techniques to enhance the instantaneous field-of-view by more than an order of magnitude. OWFA has unique advantages for contemporary investigations related to large scale structure, transient events and space weather watch. In this paper, we describe the RF subsystems, digitizers and fibre optic communication of OWFA and highlight some specific aspects of the system relevant for the observations planned during the initial operation.

  19. Unraveling complex hydrogeologic systems using field tracer tests

    NASA Astrophysics Data System (ADS)

    Dam, William A.; Nicholson, Thomas

    Tracking the movement of underground contaminants is vital to protecting public health and the environment worldwide. Scientific efforts using field tracer techniques to solve contaminant migration problems are rapidly evolving to fill critical information gaps and provide confirmation of laboratory data and numerical models. Various chemical tracers are being used to formulate and evaluate alternative conceptual hydrogeologic modelssemi; namely, to constrain hydraulic properties of geologic systems, identify sources of groundwater, flow paths, and rates, and determine mechanisms that affect contaminant transport. Naturally occurring elements and environmental isotopes from atmospheric and underground nuclear testing can make excellent tracers. In addition, characterizing sites of future waste disposal, such as the potential high-level nuclear waste repository at Yucca Mountain, requires new and innovative techniques like injecting surrogate tracers that simulate potential contaminants and shed light on mechanisms that could control future contaminant migration.

  20. Education and Education Research: Moribund Fields or Dynamic Interacting Systems?

    ERIC Educational Resources Information Center

    Reddy, C.

    2011-01-01

    The complex field of education is often depicted as a static field governed by technocratic approaches to activities that characterise the field. Education change is equally viewed in such limited and positivistic ways and linear means-end processes (Hoban 2002). In such orientations to the field, educational research therefore, is about finding…

  1. Radial transport of large-scale magnetic fields in accretion disks. I. Steady solutions and an upper limit on the vertical field strength

    SciTech Connect

    Okuzumi, Satoshi; Takeuchi, Taku; Muto, Takayuki

    2014-04-20

    Large-scale magnetic fields are key ingredients of magnetically driven disk accretion. We study how large-scale poloidal fields evolve in accretion disks, with the primary aim of quantifying the viability of magnetic accretion mechanisms in protoplanetary disks. We employ a kinematic mean-field model for poloidal field transport and focus on steady states where inward advection of a field balances with outward diffusion due to effective resistivities. We analytically derive the steady-state radial distribution of poloidal fields in highly conducting accretion disks. The analytic solution reveals an upper limit on the strength of large-scale vertical fields attainable in steady states. Any excess poloidal field will diffuse away within a finite time, and we demonstrate this with time-dependent numerical calculations of the mean-field equations. We apply this upper limit to large-scale vertical fields threading protoplanetary disks. We find that the maximum attainable strength is about 0.1 G at 1 AU, and about 1 mG at 10 AU from the central star. When combined with recent magnetic accretion models, the maximum field strength translates into the maximum steady-state accretion rate of ∼10{sup –7} M {sub ☉} yr{sup –1}, in agreement with observations. We also find that the maximum field strength is ∼1 kG at the surface of the central star provided that the disk extends down to the stellar surface. This implies that any excess stellar poloidal field of strength ≳ kG can be transported to the surrounding disk. This might in part resolve the magnetic flux problem in star formation.

  2. Intelligent shell feedback control in EXTRAP T2R reversed field pinch with partial coverage of the toroidal surface by a discrete active coil array

    NASA Astrophysics Data System (ADS)

    Yadikin, D.; Brunsell, P. R.; Drake, J. R.

    2006-01-01

    An active feedback system is required for long pulse operation of the reversed field pinch (RFP) device to suppress resistive wall modes (RWMs). A general feature of a feedback system using a discrete active coil array is a coupling effect which arises when a set of side band modes determined by the number of active coils is produced. Recent results obtained on the EXTRAP T2R RFP demonstrated the suppression of independent m = 1 RWMs using an active feedback system with a two-dimensional array of discrete active coils in the poloidal and toroidal directions. One of the feedback algorithms used is the intelligent shell feedback scheme. Active feedback systems having different number of active coils in the poloidal (Mc) and toroidal (Nc) directions (Mc × Nc = 2 × 32 and Mc × Nc = 4 × 16) are studied. Different side band effects are seen for these configurations. A significant prolongation of the plasma discharge is achieved for the intelligent shell feedback scheme using the 2 × 32 active coil configuration. This is attributed to the side band sets including only one of the dominant unstable RWMs and avoiding coupling to resonant modes. Analog proportional-integral-derivative controllers are used in the feedback system. Regimes with different values of the proportional gain are studied. The requirement of the proportional-integral control for low proportional gain and proportional-derivative control for high proportional gain is seen in the experiments.

  3. Niosomes as Nano-Delivery Systems in the Pharmaceutical Field.

    PubMed

    Cerqueira-Coutinho, Cristal; Dos Santos, Elisabete P; Mansur, Claudia Regina E

    2016-01-01

    Nanosystems used in the pharmaceutical field aim to guarantee a controlled release and efficacy boost with dose reduction of the drug. The same active ingredient could be vehiculated in different concentrations in distinct nanosystems. Among these nanostructures, the vesicular ones present a versatile delivery system that could be applied to encapsulate lipophilic, amphiphilic, and hydrophilic compounds. Liposomes are the most well-known vesicular nanosystems; however, there are others, such as niosomes, that are composed of nonionic surfactants that are polymeric or conventional. Niosomes could be prepared using the thin film hydration method, in which the active ingredient is solubilized in organic solvent with the surfactant or in aqueous solution depending on its polarity. In addition, co-surfactants could be used to improve stabilization and vesicle integrity because they occupy regions in the interface where the mainly surfactant could not reach. Vesicular nanosystems could be characterized by different techniques, such as microscopy, dynamic light scattering, nuclear magnetic resonance, and others. These nanostructures could be applied to drugs (administered by different routes) or to gene and cosmetic delivery systems.

  4. Evolution of the Snorre Field downhole completion systems

    SciTech Connect

    Gunnarsson, B.; Toennessen, S.H.; Stensland, J.F.; Haut, R.C.

    1994-12-31

    This paper discusses the development and evolution of cost-effective downhole completion systems for the Snorre Field Tension Leg Platform (TLP) and Subsea Production System (SPS). Included is a discussion of operational experiences that influenced the evolution. Also included in the paper are specific examples of how the completion times were reduced. The completion design for the subsea wells includes some new features compared to previous through flow line (TFL) completions. During the design process cost, safety and simplicity have been the driving forces for selecting equipment. Previous TFL completions have normally included a H-member, dual packers, sliding sleeves and nipples in each tail pipe. This design required plugs and standing valves to be an integral part of the completion string, requiring high reliability of the TFL retrievable components. The completion design used for the Snorre SPS wells uses a minimum amount of tubular components. The design does not require any TFL retrievable components to be installed during production or injection. This minimizes the number of flow restrictions and thereby reduces the tendency for scaling, erosion and corrosion on the TFL retrievable components. All tubing retrievable components, including the Y-block, are qualified and are considered standard today.

  5. A next generation field-portable goniometer system

    NASA Astrophysics Data System (ADS)

    Harms, Justin D.; Bachmann, Charles M.; Faulring, Jason W.; Ruiz Torres, Andres J.

    2016-05-01

    Various field portable goniometers have been designed to capture in-situ measurements of a materials bi-directional reflectance distribution function (BRDF), each with a specific scientific purpose in mind.1-4 The Rochester Institute of Technology's (RIT) Chester F. Carlson Center for Imaging Science recently created a novel instrument incorporating a wide variety of features into one compact apparatus in order to obtain very high accuracy BRDFs of short vegetation and sediments, even in undesirable conditions and austere environments. This next generation system integrates a dual-view design using two VNIR/SWIR pectroradiometers to capture target reflected radiance, as well as incoming radiance, to provide for better optical accuracy when measuring in non-ideal atmospheric conditions or when background illumination effects are non-negligible. The new, fully automated device also features a laser range finder to construct a surface roughness model of the target being measured, which enables the user to include inclination information into BRDF post-processing and further allows for roughness effects to be better studied for radiative transfer modeling. The highly portable design features automatic leveling, a precision engineered frame, and a variable measurement plane that allow for BRDF measurements on rugged, un-even terrain while still maintaining true angular measurements with respect to the target, all without sacrificing measurement speed. Despite the expanded capabilities and dual sensor suite, the system weighs less than 75 kg, which allows for excellent mobility and data collection on soft, silty clay or fine sand.

  6. Two-level systems driven by large-amplitude fields

    SciTech Connect

    Ashhab, S.; Johansson, J. R.; Zagoskin, A. M.; Nori, Franco

    2007-06-15

    We analyze the dynamics of a two-level system subject to driving by large-amplitude external fields, focusing on the resonance properties in the case of driving around the region of avoided level crossing. In particular, we consider three main questions that characterize resonance dynamics: (1) the resonance condition (2) the frequency of the resulting oscillations on resonance, and (3) the width of the resonance. We identify the regions of validity of different approximations. In a large region of the parameter space, we use a geometric picture in order to obtain both a simple understanding of the dynamics and quantitative results. The geometric approach is obtained by dividing the evolution into discrete time steps, with each time step described by either a phase shift on the basis states or a coherent mixing process corresponding to a Landau-Zener crossing. We compare the results of the geometric picture with those of a rotating wave approximation. We also comment briefly on the prospects of employing strong driving as a useful tool to manipulate two-level systems.

  7. Virtually distortion-free imaging system for large field, high resolution lithography

    DOEpatents

    Hawryluk, Andrew M.; Ceglio, Natale M.

    1993-01-01

    Virtually distortion free large field high resolution imaging is performed using an imaging system which contains large field distortion or field curvature. A reticle is imaged in one direction through the optical system to form an encoded mask. The encoded mask is then imaged back through the imaging system onto a wafer positioned at the reticle position.

  8. Virtually distortion-free imaging system for large field, high resolution lithography

    DOEpatents

    Hawryluk, A.M.; Ceglio, N.M.

    1993-01-05

    Virtually distortion free large field high resolution imaging is performed using an imaging system which contains large field distortion or field curvature. A reticle is imaged in one direction through the optical system to form an encoded mask. The encoded mask is then imaged back through the imaging system onto a wafer positioned at the reticle position.

  9. Develop a field grid system for yield mapping and machine control. Final report, Invention 544

    SciTech Connect

    1995-12-15

    The objective of this project was to build and test the Field Grid Sense system for yield mapping and machine control during harvesting. Secondly, to use Field Grid Sense system with chemical application equipment to demonstrate a workable in-field system. This document contains summarized quarterly reports.

  10. Reversed field pinch current drive with oscillating helical fields

    SciTech Connect

    Farengo, Ricardo; Clemente, Roberto Antonio

    2006-04-15

    The use of oscillating helical magnetic fields to produce and sustain the toroidal and poloidal currents in a reversed field pinch (RFP) is investigated. A simple physical model that assumes fixed ions, massless electrons, and uniform density and resistivity is employed. Thermal effects are neglected in Ohm's law and helical coordinates are introduced to reduce the number of coupled nonlinear equations that must be advanced in time. The results show that it is possible to produce RFP-like magnetic field profiles with pinch parameters close to the experimental values. The efficiencies obtained for moderate resistivity, and the observed scaling, indicate that this could be a very attractive method for high temperature plasmas.

  11. Final Report for Propylene Dissemination System for FUSION Field Trials

    DTIC Science & Technology

    2007-03-01

    1 m/s. Field Controller Design The field controller employs a ’BRAT’ single board computer (SBC) with customized firmware to manage all local...Field Control Panel are the single board computer , interface electronics for the flow rate measurement flow control and ancillary (pressure and

  12. Field Techniques: Atlantic Barrier System. Field Guidebook. National Association of Geology Teachers Eastern Section Annual Field Conference (Lewes, Delaware, April 26-29, 1984).

    ERIC Educational Resources Information Center

    O'Connor, James V., Ed.; Tormey, Brian B., Ed.

    The Atlantic barrier system is used as a focal point in this manual of field exercises. A collection of activities and posed questions provide students with opportunities to develop skills basic to the development of sound field techniques. Investigations can be adapted and modified by teachers to specific subject areas and developmental needs.…

  13. Exact integrability in quantum field theory and statistical systems

    NASA Astrophysics Data System (ADS)

    Thacker, H. B.

    1981-04-01

    The properties of exactly integrable two-dimensional quantum systems are reviewed and discussed. The nature of exact integrability as a physical phenomenon and various aspects of the mathematical formalism are explored by discussing several examples, including detailed treatments of the nonlinear Schrödinger (delta-function gas) model, the massive Thirring model, and the six-vertex (ice) model. The diagonalization of a Hamiltonian by Bethe's Ansatz is illustrated for the nonlinear Schrödínger model, and the integral equation method of Lieb for obtaining the spectrum of the many-body system from periodic boundary conditions is reviewed. Similar methods are applied to the massive Thirring model, where the fermion-antifermion and bound-state spectrum are obtained explicitly by the integral equation method. After a brief review of the classical inverse scattering method, the quantum inverse method for the nonlinear Schrödinger model is introduced and shown to be an algebraization of the Bethe Ansatz technique. In the quantum inverse method, an auxiliary linear problem is used to define nonlocal operators which are functionals of the original local field on a fixed-time string of arbitrary length. The particular operators for which the string is infinitely long (free boundary conditions) or forms a closed loop around a cylinder (periodic boundary conditions) correspond to the quantized scattering data and have a special significance. One of them creates the Bethe eigenstates, while the other is the generating function for an infinite number of conservation laws. The analogous operators on a lattice are constructed for the symmetric six-vertex model, where the object which corresponds to a solution of the auxiliary linear problem is a string of vertices contracted over horizontal links (arrows). The relationship between the quantum inverse method and the transfer matrix formalism is exhibited. The inverse Gel'fand-Levitan transform which expresses the local field

  14. Magneto-optical micromechanical systems for magnetic field mapping

    PubMed Central

    Truong, Alain; Ortiz, Guillermo; Morcrette, Mélissa; Dietsch, Thomas; Sabon, Philippe; Joumard, Isabelle; Marty, Alain; Joisten, Hélène; Dieny, Bernard

    2016-01-01

    A new method for magnetic field mapping based on the optical response of organized dense arrays of flexible magnetic cantilevers is explored. When subjected to the stray field of a magnetized material, the mobile parts of the cantilevers deviate from their initial positions, which locally changes the light reflectivity on the magneto-optical surface, thus allowing to visualize the field lines. While the final goal is to be able to map and quantify non-uniform fields, calibrating and testing the device can be done with uniform fields. Under a uniform field, the device can be assimilated to a magnetic-field-sensitive diffraction grating, and therefore, can be analyzed by coherent light diffraction. A theoretical model for the diffraction patterns, which accounts for both magnetic and mechanical interactions within each cantilever, is proposed and confronted to the experimental data. PMID:27531037

  15. Hall attractor in axially symmetric magnetic fields in neutron star crusts.

    PubMed

    Gourgouliatos, Konstantinos N; Cumming, Andrew

    2014-05-02

    We find an attractor for an axially symmetric magnetic field evolving under the Hall effect and subdominant Ohmic dissipation, resolving the question of the long-term fate of the magnetic field in neutron star crusts. The electron fluid is in isorotation, analogous to Ferraro's law, with its angular velocity being approximately proportional to the poloidal magnetic flux, Ω∝Ψ. This equilibrium is the long-term configuration of a magnetic field evolving because of the Hall effect and Ohmic dissipation. For an initial dipole-dominated field, the attractor consists mainly of a dipole and an octupole component accompanied by an energetically negligible quadrupole toroidal field. The field dissipates in a self-similar way: Although higher multipoles should decay faster, the toroidal field mediates transfer of energy into them from the lower ones, leading to an advection diffusion equilibrium and keeping the ratio of the poloidal multipoles almost constant. This has implications for the structure of the intermediate-age neutron stars, suggesting that their poloidal field should consist of a dipole and an octupole component accompanied by a very weak toroidal quadrupole. For initial conditions that have a higher multipole ℓ structure, the attractor consists mainly of ℓ and ℓ+2 poloidal components.

  16. Influence of exposure to electromagnetic field on the cardiovascular system.

    PubMed

    Jeong, J H; Kim, J S; Lee, B C; Min, Y S; Kim, D S; Ryu, J S; Soh, K S; Seo, K M; Sohn, U D

    2005-01-01

    1 We examined whether extremely low frequency electromagnetic fields (ELF-EMF) affect the basal level of cardiovascular parameters and influence of drugs acting on the sympathetic nervous system. 2 Male rats were exposed to sham control and EMF (60 Hz, 20 G) for 1 (MF-1) or 5 days (MF-5). We evaluated the alterations of blood pressure (BP), pulse pressure (PP), heart rate (HR), and the PR interval, QRS interval and QT interval on the electrocardiogram and dysrhythmic ratio in basal level and dysrhythmia induced by beta-adrenoceptor agonists. 3 In terms of the basal levels, there were no statistically significant differences among control, MF-1 and MF-5 in PR interval, QRS interval, mean BP, HR and PP. However, the QT interval, representing ventricular repolarization, was significantly reduced by MF-1 (P < 0.05). 4 (-)-Dobutamine (beta1-adrenoceptor-selective agonist)-induced tachycardia was significantly suppressed by ELF-EMF exposure in MF-1 for the increase in HR (DeltaHR), the decrease in QRS interval (DeltaQRS) and the decrease in QT (DeltaQT) interval. Adrenaline (nonselective beta-receptor agonist)-induced dysrhythmia was also significantly suppressed by ELF-EMF in MF-1 for the number of missing beats, the dysrhythmic ratio, and the increase in BP and PP. 5 These results indicated that 1-day exposure to ELF-EMF (60 Hz, 20 G) could suppress the increase in HR by affecting ventricular repolarization and may have a down-regulatory effect on responses of the cardiovascular system induced by sympathetic agonists.

  17. Handheld standoff mine detection system (HSTAMIDS) field evaluation in Namibia

    NASA Astrophysics Data System (ADS)

    Doheny, Robert C.; Burke, Sean; Cresci, Roger; Ngan, Peter; Walls, Richard; Chernoff, Jeff

    2006-05-01

    The Humanitarian Demining Research and Development Program of the US Army RDECOM CERDEC Night Vision and Electronic Sensors Directorate (NVESD), under the direction of the Office of Assistant Secretary of Defense for Special Operations and Low-Intensity Conflict (OASD SO/LIC) and with participation from the International Test and Evaluation Program (ITEP) for humanitarian demining, conducted an in-country field evaluation of the Handheld Standoff Mine Detection System (HSTAMIDS) in the southern African country of Namibia. Participants included the US Humanitarian Demining Team of NVESD; ITEP personnel from several member countries; deminers from two non-governmental organizations in Angola, Menschen Gegen Minen (MgM) and HALO Trust; and CyTerra Corporation. The primary objectives were to demonstrate the performance of the U.S. Army's newest handheld multisensor mine detector, the HSTAMIDS, to the performance of the metal detector being used by local demining organizations and also to assess the performance of deminers using the HSTAMIDS after limited experience and training.

  18. Effect of electromagnetic field exposure on the reproductive system

    PubMed Central

    Park, Chan Jin

    2012-01-01

    The safety of human exposure to an ever-increasing number and diversity of electromagnetic field (EMF) sources both at work and at home has become a public health issue. To date, many in vivo and in vitro studies have revealed that EMF exposure can alter cellular homeostasis, endocrine function, reproductive function, and fetal development in animal systems. Reproductive parameters reported to be altered by EMF exposure include male germ cell death, the estrous cycle, reproductive endocrine hormones, reproductive organ weights, sperm motility, early embryonic development, and pregnancy success. At the cellular level, an increase in free radicals and [Ca2+]i may mediate the effect of EMFs and lead to cell growth inhibition, protein misfolding, and DNA breaks. The effect of EMF exposure on reproductive function differs according to frequency and wave, strength (energy), and duration of exposure. In the present review, the effects of EMFs on reproductive function are summarized according to the types of EMF, wave type, strength, and duration of exposure at cellular and organism levels. PMID:22563544

  19. Cooperative field test program for wind systems. Final report

    SciTech Connect

    Bollmeier, W.S. II; Dodge, D.M.

    1992-03-01

    The objectives of the Federal Wind Energy Program, managed by the US Department of Energy (DOE), are (1) to assist industry and utilities in achieving a multi-regional US market penetration of wind systems, and (2) to establish the United States as the world leader in the development of advanced wind turbine technology. In 1984, the program conducted a series of planning workshops with representatives from the wind energy industry to obtain input on the Five-Year Research Plan then being prepared by DOE. One specific suggestion that came out of these meetings was that the federal program should conduct cooperative research tests with industry to enhance the technology transfer process. It was also felt that the active involvement of industry in DOE-funded research would improve the state of the art of wind turbine technology. DOE established the Cooperative Field Test Program (CFTP) in response to that suggestion. This program was one of the first in DOE to feature joint industry-government research test teams working toward common objectives.

  20. Triaxial magnetic field gradient system for microcoil magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Seeber, D. A.; Hoftiezer, J. H.; Daniel, W. B.; Rutgers, M. A.; Pennington, C. H.

    2000-11-01

    There is a great advantage in signal to noise ratio (S/N) that can be obtained in nuclear magnetic resonance (NMR) experiments on very small samples (having spatial dimensions ˜100 μm or less) if one employs NMR "micro" receiver coils, "microcoils," which are of similarly small dimensions. The gains in S/N could enable magnetic resonance imaging (MRI) microscopy with spatial resolution of ˜1-2 μm, much better than currently available. Such MRI microscopy however requires very strong (>10 T/m), rapidly switchable triaxial magnetic field gradients. Here, we report the design and construction of such a triaxial gradient system, producing gradients substantially greater than 15 T/m in all three directions, x, y, and z (and as high as 50 T/m for the x direction). The gradients are switchable within time ˜10 μs and adequately uniform (within 5% over a volume of [600μm3] for microcoil MRI of small samples.

  1. Molten metal feed system controlled with a traveling magnetic field

    DOEpatents

    Praeg, Walter F.

    1991-01-01

    A continuous metal casting system in which the feed of molten metal is controlled by means of a linear induction motor capable of producing a magnetic traveling wave in a duct that connects a reservoir of molten metal to a caster. The linear induction motor produces a traveling magnetic wave in the duct in opposition to the pressure exerted by the head of molten metal in the reservoir so that p.sub.c =p.sub.g -p.sub.m where p.sub.c is the desired pressure in the caster, p.sub.g is the gravitational pressure in the duct exerted by the force of the head of molten metal in the reservoir, and p.sub.m is the electromagnetic pressure exerted by the force of the magnetic field traveling wave produced by the linear induction motor. The invention also includes feedback loops to the linear induction motor to control the casting pressure in response to measured characteristics of the metal being cast.

  2. Magnetic fields, plasmas, and coronal holes: The inner solar system

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.

    1978-01-01

    In situ magnetic field and plasma observations within 1 AU which describe MDH stream flows and Alfvenic fluctuations, the latest theories of those phenomena are discussed. Understanding of streams and fluctuations was enhanced by the acquisition of nearly complete sets of high resolution plasma and magnetic data simultaneously at two or more points by IMPs 6, 7, and 8, Mariner-Venus-Mercury, HELIOS 1, and HELIOS 2. Observations demonstrate that streams can have very thin boundaries in latitude and longitude near the sun. This has necessitated a revision of earlier views of stream dynamics, for it is now clear that magnetic pressure is a major factor in the dynamics of stream in the inner solar system and that nonlinear phenomena are significant much closer to the sun than previously believed. Simultaneous IMP 6, 7, and 8 observations of Alfvenic fluctuations indicate that they are probably not simply transverse Alfven waves and suggest that Alfvenic fluctuations are better described as nonplanar, large-amplitude, general Alfven waves moving through an inhomogeneous and discontinuous medium, and coupled to a compressive mode.

  3. Quantum analysis applied to thermo field dynamics on dissipative systems

    SciTech Connect

    Hashizume, Yoichiro; Okamura, Soichiro; Suzuki, Masuo

    2015-03-10

    Thermo field dynamics is one of formulations useful to treat statistical mechanics in the scheme of field theory. In the present study, we discuss dissipative thermo field dynamics of quantum damped harmonic oscillators. To treat the effective renormalization of quantum dissipation, we use the Suzuki-Takano approximation. Finally, we derive a dissipative von Neumann equation in the Lindbrad form. In the present treatment, we can easily obtain the initial damping shown previously by Kubo.

  4. Frequency-Poloidal Wave Number Spectral Analysis of Turbulence in QH-mode plasmas Measured with BES on DIII-D

    NASA Astrophysics Data System (ADS)

    Ono, M.; Ida, K.; Kobayashi, T.; Yoshinuma, M.; McKee, G. R.; Yan, Z.; Burrell, K. H.; Chen, X.

    2016-10-01

    Quiescent H-mode (QH) is an ELM-free scenario with good energy confinement, constant density, and radiated power, with a pedestal localized electromagnetic mode (edge harmonic oscillation, EHO) providing continuous particle transport. The features and characteristics of QH-mode plasma turbulence in the wavenumber-frequency domain are crucial to understanding the mechanisms and dynamics of the enhanced particle transport. Frequency-wavenumber spectral analysis was applied to localized density fluctuation data measured with BES on DIII-D in the region of 0.8 < ρ < 1.0 . In the analysis, a Maximum Entropy Method is applied in the space domain, instead of an FFT, to estimate a well resolved k-spectrum spectrum from truncated data. The fundamental frequency of the EHO was typically 10 kHz with long poloidal wavelength (kθ 0.02cm-1), while broadband turbulence was observed in the range of 50-200 kHz with correlation lengths of a few cm. The broadband turbulence measured at ρ 0.9 was found to have poloidal phase velocity of 10 km/s, which corresponds to the E ×B velocity. Work supported by US DOE Grant DE-FC02-04ER54698.

  5. Ordering and phase transitions in random-field Ising systems

    NASA Technical Reports Server (NTRS)

    Maritan, Amos; Swift, Michael R.; Cieplak, Marek; Chan, Moses H. W.; Cole, Milton W.; Banavar, Jayanth R.

    1991-01-01

    An exact analysis of the Ising model with infinite-range interactions in a random field and a local mean-field theory in three dimensions is carried out leading to a phase diagram with several coexistence surfaces and lines of critical points. The results show that the phase diagram depends crucially on whether the distribution of random fields is symmetric or not. Thus, Ising-like phase transitions in a porous medium (the asymmetric case) are in a different universality class from the conventional random-field model (symmetric case).

  6. A comparison of satellite systems for gravity field measurements

    NASA Technical Reports Server (NTRS)

    Argentiero, P. D.; Lowrey, B. E.

    1977-01-01

    A detailed and accurate earth gravity field model is important to the understanding of the structure and composition of the earth's crust and upper mantle. Various satellite-based techniques for providing more accurate models of the gravity field are analyzed and compared. A high-low configuration satellite-to-satellite tracking mission is recommended for the determination of both the long wavelength and short wavelength portions of the field. Satellite altimetry and satellite gradiometry missions are recommended for determination of the short wavelength portion of the field.

  7. Designing a Field Experience Tracking System in the Area of Special Education

    ERIC Educational Resources Information Center

    He, Wu; Watson, Silvana

    2014-01-01

    Purpose: To improve the quality of field experience, support field experience cooperation and streamline field experience management, the purpose of this paper is to describe the experience in using Activity Theory to design and develop a web-based field experience tracking system for a special education program. Design/methodology/approach: The…

  8. Field Error Analysis and a Correction Scheme for the KSTAR device

    NASA Astrophysics Data System (ADS)

    You, K.-I.; Lee, D. K.; Jhang, Hogun; Lee, G.-S.; Kwon, K. H.

    2000-10-01

    Non-axisymmetric error fields can lead to tokamak plasma performance degradation and ultimately premature plasma disruption, if some error field components are larger than threshold values. The major sources of the field error include the unavoidable winding irregularities of the poloidal field coils during manufacturing, poloidal field and toroidal field coils misalignments during installation, stray fields from bus and lead wires between coils and power supplies, and welded joints of the vacuum vessel. Numerical simulation results are presented for Fourier harmonics of the error field obtained on the (m,n) = (2,1) resonant flux surface with a coil current set for the reference equilibrium configuration. Field error contributions are considered separately for all major error sources. An error correction scheme designed to reduce key components of the total net error field is also discussed in relation to the field error correction coils inside the vacuum vessel.

  9. 47 CFR 90.359 - Field strength limits for EA-licensed LMS systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Field strength limits for EA-licensed LMS... § 90.359 Field strength limits for EA-licensed LMS systems. EA-licensed multilateration systems shall limit the field strength of signals transmitted from their base stations to 47 dBuV/m at their...

  10. A double magnetic solar cycle and dynamical systems

    NASA Astrophysics Data System (ADS)

    Popova, H.

    Various solar activity data have indicated that along with the well-known 22-year cycle there is a shorter periodicity of about 2 years. To simulate this phenomenon, we constructed a dynamical system, which reproduced double-periodic behaviour of the solar cycle. Such nonlinear dynamical system described the solar αω-dynamo process with variable intensities Rα and Rω of the α-effect and the differential rotation, respectively. We have plotted the time distribution and butterfly diagrams for the poloidal and toroidal magnetic fields with dipole and quadrupole symmetries. The dynamical system with dipole symmetry of the magnetic field reproduces a regime similar to the double cycle at -450 < RαRω < -210. In the case of quadrupole symmetry, this regime exists at -220 < RαRω < -190.

  11. Study of the confinement properties in a reversed-field pinch with mode rotation and gas fuelling

    NASA Astrophysics Data System (ADS)

    Cecconello, M.; Malmberg, J.-A.; Nielsen, P.; Pasqualotto, R.; Drake, J. R.

    2002-08-01

    An extensive investigation of the global confinement properties in different operating scenarios in the rebuilt EXTRAP T2R reversed-field pinch (RFP) experiment is reported here. In particular, the role of a fast gas puff valve system, used to control plasma density, on confinement is studied. Without gas puffing, the electron density decays below 0.5×1019 m-3. The poloidal beta varies between 5% and 15%, decreasing at large I/N. The energy confinement time ranges from 70 to 225 μs. With gas puffing, the density is sustained at ne≈1.5×1019 m-3. However, a general slight deterioration of the plasma performances is observed for the same values of I/N: the plasma becomes cooler and more radiative. The poloidal beta is comparable to that in the scenarios without puff but the energy confinement time drops ranging from 60 to 130 μs. The fluctuation level and the energy confinement time have been found to scale with the Lundquist number as S-0.05+/-0.07 and S0.5+/-0.1, respectively. Mode rotation is typical for all the discharges and rotation velocity is observed to increase with increasing electron diamagnetic velocity.

  12. Anomalies in the applied magnetic fields in DIII-D and their implications for the understanding of stability experiments

    SciTech Connect

    Luxon, J. L.; Schaffer, M. J.; Jackson, G. L.; Leuer, J. A.; Nagy, A.; Scoville, J. T.; Strait, E. J.

    2003-12-01

    Small non-axisymmetric magnetic fields are known to cause serious loss of stability in tokamaks leading to loss of confinement and abrupt termination of plasma current (disruptions). The best known examples are the locked mode and the resistive wall mode. Understanding of the underlying field anomalies (departures in the hardware-related fields from ideal toroidal and poloidal fields on a single axis) and the interaction of the plasma with them is crucial to tokamak development. Results of both locked mode experiments and resistive wall mode experiments done in DIII-D tokamak plasmas have been interpreted to indicate the presence of a significant anomalous field. New measurements of the magnetic field anomalies of the hardware systems have been made on DIII-D. The measured field anomalies due to the plasma shaping coils in DIII-D are smaller than previously reported. Additional evaluations of systematic errors have been made. New measurements of the anomalous fields of the ohmic heating and toroidal coils have been added. Such detailed in situ measurements of the fields of a tokamak are unique. The anomalous fields from all of the coils are one third of the values indicated from the stability experiments. These results indicate limitations in the understanding of the interaction of the plasma with the external field. They indicate that it may not be possible to deduce the anomalous fields in a tokamak from plasma experiments and that we may not have the basis needed to project the error field requirements of future tokamaks.

  13. Field-balanced adaptive optics error function for wide field-of-view space-based systems

    NASA Astrophysics Data System (ADS)

    McComas, Brian K.; Friedman, Edward J.

    2002-03-01

    Adaptive optics are regularly used in ground-based astronomical telescopes. These applications are characterized by a very narrow (approximately 1 arcmin) field of view. For economic reasons, commercial space-based earth-observing optical systems must have a field of view as large as possible. We develop a new error function that is an extension of conventional adaptive optics for wide field-of-view optical systems and show that this new error function enables diffraction-limited performance across a large field of view with only one deformable mirror. This new error function allows for reprogramming of aberration control algorithms for particular applications by the use of an addressable weighting function.

  14. Breast positioning system for full field digital mammography and digital breast tomosynthesis system

    NASA Astrophysics Data System (ADS)

    Varjonen, Mari; Pamilo, Martti; Hokka, Pirjo; Hokkanen, Riina; Strömmer, Pekka

    2007-03-01

    This paper will present a new breast positioning system for amorphous selenium (a-Se) based full field digital mammography (FFDM) system, which is also a platform of tomosynthesis prototype. Clinical images demonstrate that this method is capable extending the breast away from the chest wall, and maximizing the breast volume. Breast positioning system consists of two transparent moving sheets that apply traction of the breast controlled by motor. Sheets are under and above the compressed breast. Breast positioning sheets pull the breast into the imaging area during the compression. Digital mammography system is based on amorphous selenium flat panel detector (FPD) technology where the overall thickness of the selenium structure is 200 μm, and the pixel size on this detector is 85 μm. Preliminary results will be presented. Clinical study showed increment of the breast volume imaged, and it brought up to 1.0 cm - 2.0 cm more breast tissue. New breast position system also holds a promise of slight decrement of compression force used in the examination. Maximizing the exposured breast tissue is complicated, but important aspect in the breast cancer detection and diagnosis. Increasing the field of view with an additional volume of breast tissue imaged is a key point in digital mammography and digital breast tomosynthesis (DBT).

  15. Quasioptical design of integrated Doppler backscattering and correlation electron cyclotron emission systems on the DIII-D tokamak

    SciTech Connect

    Rhodes, T. L.; Peebles, W. A.; Nguyen, X.; Hillesheim, J. C.; Schmitz, L.; Wang, G.; White, A. E.

    2010-10-15

    The quasioptical design of a new integrated Doppler backscattering (DBS) and correlation electron cyclotron emission (CECE) system is presented. The design provides for simultaneous measurements of intermediate wavenumber density and long wavelength electron temperature turbulence behavior. The Doppler backscattering technique is sensitive to plasma turbulence flow and has been utilized to determine radial electric field, geodesic acoustic modes, zonal flows, and intermediate scale (k{approx}1-6 cm{sup -1}) density turbulence. The correlation ECE system measures a second turbulent field, electron temperature fluctuations, and is sensitive to long poloidal wavelength (k{<=}1.8 cm{sup -1}). The integrated system utilizes a newly installed in-vessel focusing mirror that produces a beam waist diameter of 3.5-5 cm in the plasma depending on the frequency. A single antenna (i.e., monostatic operation) is used for both launch and receive. The DBS wavenumber is selected via an adjustable launch angle and variable probing frequency. Due to the unique system design both positive and negative wavenumbers can be obtained, with a range of low to intermediate wavenumbers possible (approximately -3 to 10 cm{sup -1}). A unique feature of the design is the ability to place the DBS and CECE measurements at the same radial and poloidal locations allowing for cross correlation studies (e.g., measurement of nT cross-phase).

  16. System for controllable magnetic measurement with direct field determination

    NASA Astrophysics Data System (ADS)

    Stupakov, O.

    2012-02-01

    This work describes a specially designed setup for magnetic hysteresis and Barkhausen noise measurements. The setup combines two main elements: an improved fast algorithm to control the waveform of magnetic induction and simultaneous direct determination of the magnetic field. The digital feedback algorithm uses only the previous measurement cycle to correct the magnetization voltage without any additional correlation parameter; it usually converges after several tens of cycles. The magnetic field is measured at the sample surface using a vertically mounted array of sensitive Hall sensors. Linear extrapolation of the tangential field profile to the sample surface determines the true waveform of the magnetic field. This unique combination of physically based control for both parameters of the magnetization process provides stable and reliable results, which are independent of a specified experimental configuration. This is illustrated for the industrially attractive measurements of non-oriented electrical steels with a 50 Hz sinusoidal induction waveform.

  17. Dirichlet boundary conditions for arbitrary-shaped boundaries in stellarator-like magnetic fields for the Flux-Coordinate Independent method

    NASA Astrophysics Data System (ADS)

    Hill, Peter; Shanahan, Brendan; Dudson, Ben

    2017-04-01

    We present a technique for handling Dirichlet boundary conditions with the Flux Coordinate Independent (FCI) parallel derivative operator with arbitrary-shaped material geometry in general 3D magnetic fields. The FCI method constructs a finite difference scheme for ∇∥ by following field lines between poloidal planes and interpolating within planes. Doing so removes the need for field-aligned coordinate systems that suffer from singularities in the metric tensor at null points in the magnetic field (or equivalently, when q → ∞). One cost of this method is that as the field lines are not on the mesh, they may leave the domain at any point between neighbouring planes, complicating the application of boundary conditions. The Leg Value Fill (LVF) boundary condition scheme presented here involves an extrapolation/interpolation of the boundary value onto the field line end point. The usual finite difference scheme can then be used unmodified. We implement the LVF scheme in BOUT++ and use the Method of Manufactured Solutions to verify the implementation in a rectangular domain, and show that it does not modify the error scaling of the finite difference scheme. The use of LVF for arbitrary wall geometry is outlined. We also demonstrate the feasibility of using the FCI approach in no n-axisymmetric configurations for a simple diffusion model in a "straight stellarator" magnetic field. A Gaussian blob diffuses along the field lines, tracing out flux surfaces. Dirichlet boundary conditions impose a last closed flux surface (LCFS) that confines the density. Including a poloidal limiter moves the LCFS to a smaller radius. The expected scaling of the numerical perpendicular diffusion, which is a consequence of the FCI method, in stellarator-like geometry is recovered. A novel technique for increasing the parallel resolution during post-processing, in order to reduce artefacts in visualisations, is described.

  18. A Dual-Field Sensing Scheme for a Guidance System for the Blind

    PubMed Central

    Lin, Qing; Han, Youngjoon

    2016-01-01

    An electronic guidance system is very helpful in improving blind people’s perceptions in a local environment. In our previous work “Lin, Q.; Han, Y. A Context-Aware-Based Audio Guidance System for Blind People Using a Multimodal Profile Model. Sensors 2014, 14, 18670–18700”, a context-aware guidance system using a combination of a laser scanner and a camera was proposed. By using a near-field graphical model, the proposed system could interpret a near-field scene in very high resolution. In this paper, our work is extended by adding a far-field graphical model. The integration of the near-field and the far-field models constitutes a dual-field sensing scheme. In the near-field range, reliable inference of the ground and object status is obtained by fusing range data and image data using the near-field graphical model. In the far-field range, which only the camera can cover, the far-field graphical model is proposed to interpret far-field image data based on appearance and spatial prototypes built using the near-field interpreted data. The dual-field sensing scheme provides a solution for the guidance systems to optimise their scene interpretation capability using simple sensor configurations. Experiments under various local conditions were conducted to show the efficiency of the proposed scheme in improving blind people’s perceptions in urban environments. PMID:27187388

  19. System and method for generating steady state confining current for a toroidal plasma fusion reactor

    DOEpatents

    Bers, Abraham

    1981-01-01

    A system for generating steady state confining current for a toroidal plasma fusion reactor providing steady-state generation of the thermonuclear power. A dense, hot toroidal plasma is initially prepared with a confining magnetic field with toroidal and poloidal components. Continuous wave RF energy is injected into said plasma to estalish a spectrum of traveling waves in the plasma, where the traveling waves have momentum components substantially either all parallel, or all anti-parallel to the confining magnetic field. The injected RF energy is phased to couple to said traveling waves with both a phase velocity component and a wave momentum component in the direction of the plasma traveling wave components. The injected RF energy has a predetermined spectrum selected so that said traveling waves couple to plasma electrons having velocities in a predetermined range .DELTA.. The velocities in the range are substantially greater than the thermal electron velocity of the plasma. In addition, the range is sufficiently broad to produce a raised plateau having width .DELTA. in the plasma electron velocity distribution so that the plateau electrons provide steady-state current to generate a poloidal magnetic field component sufficient for confining the plasma. In steady state operation of the fusion reactor, the fusion power density in the plasma exceeds the power dissipated inthe plasma.

  20. System and method for generating steady state confining current for a toroidal plasma fusion reactor

    DOEpatents

    Fisch, Nathaniel J.

    1981-01-01

    A system for generating steady state confining current for a toroidal plasma fusion reactor providing steady-state generation of the thermonuclear power. A dense, hot toroidal plasma is initially prepared with a confining magnetic field with toroidal and poloidal components. Continuous wave RF energy is injected into said plasma to establish a spectrum of traveling waves in the plasma, where the traveling waves have momentum components substantially either all parallel, or all anti-parallel to the confining magnetic field. The injected RF energy is phased to couple to said traveling waves with both a phase velocity component and a wave momentum component in the direction of the plasma traveling wave components. The injected RF energy has a predetermined spectrum selected so that said traveling waves couple to plasma electrons having velocities in a predetermined range .DELTA.. The velocities in the range are substantially greater than the thermal electron velocity of the plasma. In addition, the range is sufficiently broad to produce a raised plateau having width .DELTA. in the plasma electron velocity distribution so that the plateau electrons provide steady-state current to generate a poloidal magnetic field component sufficient for confining the plasma. In steady state operation of the fusion reactor, the fusion power density in the plasma exceeds the power dissipated in the plasma.

  1. The intellectual information system for management of geological and technical arrangements during oil field exploitation

    NASA Astrophysics Data System (ADS)

    Markov, N. G.; Vasilyeva, E. E.; Evsyutkin, I. V.

    2017-01-01

    The intellectual information system for management of geological and technical arrangements during oil fields exploitation is developed. Service-oriented architecture of its software is a distinctive feature of the system. The results of the cluster analysis of real field data received by means of this system are shown.

  2. Evolution and field application of a plankton imaging system

    NASA Astrophysics Data System (ADS)

    Remsen, Andrew Walker

    Understanding the processes controlling the distribution and abundance of zooplankton has been a primary concern of oceanographers and has driven the development of numerous technologies to more accurately quantify these parameters. This study investigates the potential of a new plankton imaging sensor, the shadowed image particle profiling and evaluation recorder (SIPPER), that I helped develop at the University of South Florida, to address that concern. In the first chapter, results from the SIPPER are compared against concurrently sampling plankton nets and the optical plankton counter (OPC), the most widely used optical zooplankton sampling sensor in the field. It was found that plankton nets and the SIPPER sampled robust and hard-bodied zooplankton taxa similarly while nets significantly underestimated the abundance of fragile and gelatinous taxa imaged by the SIPPER such that nets might underestimate zooplankton biomass by greater than 50%. Similarly, it was determined that the OPC misses greater than a quarter of resolvable particles due to coincident counting and that it can not distinguish between zooplankton and other abundant suspended particles such as marine snow and Trichodesmium that are difficult to quantify with traditional sampling methods. Therefore the standard method of using net samples to ground truth OPC data should be reevaluated. In the second chapter, a new automated plankton classification system was utilized to see if it was possible to use machine learning methods to classify SIPPER-imaged plankton from a diverse subtropical assemblage on the West Florida Shelf and describe their distribution during a 24 hour period. Classification accuracy for this study was similar to that of other studies in less diverse environments and similar to what could be expected by a human expert for a complex dataset. Fragile plankton taxa such as larvaceans, hydromedusae, sarcodine protoctists and Trichodesmium were found at significantly higher

  3. ELF magnetic field exposure system with feedback-controlled disturbance rejection

    SciTech Connect

    Wang, P.K.C.

    1997-06-01

    Extremely low-frequency (ELF) magnetic field exposure systems are usually subject to field disturbances induced by external sources. Here, a method for designing a feedback control system for canceling the effect of external ELF magnetic field disturbances on the magnetic field over the exposure area is presented. This method was used in the design of a feedback-controlled exposure system for an inverted microscope stage. The effectiveness of the proposed feedback control system for disturbance rejection was verified experimentally and by means of computer simulation.

  4. Program status 3. quarter -- FY 1990: Confinement systems programs

    SciTech Connect

    1990-07-24

    Highlights of the DIII-D Research Operations task are: completed five weeks tokamak operations; initiated summer vent; achievement of 10.7% beta; carried out first dimensionless transport scaling experiment; completed IBW program; demonstrated divertor heat reduction with gas puffing; field task proposals presented to OFE; presentation of DIII-D program to FPAC; made presentation to Admiral Watkins; and SAN safety review. Summaries are given on research programs, operations, program development, hardware development, operations support and collaborative efforts. Brief summaries of progress on the International Cooperation task include: TORE SUPRA, ASDEX, JFT-2M, and JET. Funding for work on CIT physics was received this quarter. Several physics R and D planning tasks were initiated. Earlier in FY90, a poloidal field coil shaping system (PFC) was found for DIGNITOR. This quarter more detailed analysis has been done to optimize the design of the PFC system.

  5. Characterizing the spin orbit torque field-like term in in-plane magnetic system using transverse field

    NASA Astrophysics Data System (ADS)

    Luo, Feilong; Goolaup, Sarjoosing; Li, Sihua; Lim, Gerard Joseph; Tan, Funan; Engel, Christian; Zhang, Senfu; Ma, Fusheng; Zhou, Tiejun; Lew, Wen Siang

    2016-08-01

    In this work, we present an efficient method for characterizing the spin orbit torque field-like term in an in-plane magnetized system using the harmonic measurement technique. This method does not require a priori knowledge of the planar and anomalous hall resistances and is insensitive to non-uniformity in magnetization, as opposed to the conventional harmonic technique. We theoretically and experimentally demonstrate that the field-like term in the Ta/Co/Pt film stack with in-plane magnetic anisotropy can be obtained by an in-plane transverse field sweep as expected, and magnetization non-uniformity is prevented by the application of fixed magnetic field. The experimental results are in agreement with the analytical calculations.

  6. Electromagnetic field redistribution in hybridized plasmonic particle-film system

    NASA Astrophysics Data System (ADS)

    Fang, Yurui; Huang, Yingzhou

    2013-04-01

    Combining simulation and experiment, we demonstrate that a metal nanoparticle dimer on a gold film substrate can confine more energy in the particle/film gap because of the hybridization of the dimer resonant lever and the continuous state of the film. The hybridization may even make the electric field enhancement in the dimer/film gap stronger than in the gap between particles. The resonant peak can be tuned by varying the size of the particles and the film thickness. This electromagnetic field redistribution has tremendous applications in sensor, photocatalysis and solar cell, etc., especially considering ultrasensitive detection of tracing molecule on substrates.

  7. Electric field measuring and display system. [for cloud formations

    NASA Technical Reports Server (NTRS)

    Wojtasinski, R. J.; Lovall, D. D. (Inventor)

    1974-01-01

    An apparatus is described for monitoring the electric fields of cloud formations within a particular area. It utilizes capacitor plates that are alternately shielded from the clouds for generating an alternating signal corresponding to the intensity of the electric field of the clouds. A synchronizing signal is produced for controlling sampling of the alternating signal. Such samplings are fed through a filter and converted by an analogue to digital converter into digital form and subsequently fed to a transmitter for transmission to the control station for recording.

  8. The Effect of Time Modulation of the Applied Fields on an RFP

    NASA Astrophysics Data System (ADS)

    Phillips, J. A.; Baker, D. A.; Gribble, R. F.

    1997-11-01

    Improved behavior of the original z-pinch has been achieved by applying different constraints. These include the following: adding a toroidal field, using a conducting shell, reversing the toroidal magnetic field near the wall, and improving shell designs giving lower field errors. Recently, reduced fluctuations and increased energy confinement have been reported(J.C. Sarff et. al., Phys. Plasmas 2, 2440 (1995).) on MST by applying a time varying poloidal voltage to the toroidal field circuit (pulsed poloidal current drive PPCD). An analogous reduction in the low frequency sawteeth was observed when oscillating field current drive OFCD(K.F. Schoenberg et. al., J. Appl. Phys. 56,2519 (1984).) was applied to ZT- 40M. It was suggested this is a manifestation of a dynamic stabilization(J.A. Phillips, D.A. Baker & R.F. Gribble, Nucl. Fusion 35, 935 (1995).). We examine the OFCD data further to document the effect of the modulation of the poloidal and toroidal voltages on the fluctuation level and the dissipative component of the power input. Comparisons with corresponding MST results are made. Past ZT-40M data( L.C. Burkhardt & J.A.Phillips, LANL Rpt., LA-8753-MS(1981).)are also investigated to examine the time variation of the applied poloidal voltage affects current density profile.

  9. Systems science and systems thinking for public health: a systematic review of the field

    PubMed Central

    Carey, Gemma; Malbon, Eleanor; Carey, Nicole; Joyce, Andrew; Crammond, Brad; Carey, Alan

    2015-01-01

    Objectives This paper reports on findings from a systematic review designed to investigate the state of systems science research in public health. The objectives were to: (1) explore how systems methodologies are being applied within public health and (2) identify fruitful areas of activity. Design A systematic review was conducted from existing literature that draws on or uses systems science (in its various forms) and relates to key public health areas of action and concern, including tobacco, alcohol, obesity and the social determinants of health. Data analysis 117 articles were included in the review. An inductive qualitative content analysis was used for data extraction. The following were systematically extracted from the articles: approach, methodology, transparency, strengths and weaknesses. These were then organised according to theme (ie, commonalities between studies within each category), in order to provide an overview of the state of the field as a whole. The assessment of data quality was intrinsic to the goals of the review itself, and therefore, was carried out as part of the analysis. Results 4 categories of research were identified from the review, ranging from editorial and commentary pieces to complex system dynamic modelling. Our analysis of each of these categories of research highlighted areas of potential for systems science to strengthen public health efforts, while also revealing a number of limitations in the dynamic systems modelling being carried out in public health. Conclusions There is a great deal of interest in how the application of systems concepts and approach might aid public health. Our analysis suggests that soft systems modelling techniques are likely to be the most useful addition to public health, and align well with current debate around knowledge transfer and policy. However, the full range of systems methodologies is yet to be engaged with by public health researchers. PMID:26719314

  10. A localized ELF magnetic field exposure system for microscope cover-slips.

    PubMed

    Wang, Paul K C

    2014-07-01

    In extremely low frequency (ELF) magnetic field exposure systems for the inverted microscope stage where the cells grown on the entire microscope cover-slip are exposed to the magnetic field, the effects of variations in cell characteristics from one cover-slip to another on the experimental data cannot be readily identified. To overcome this drawback, a localized ELF magnetic field exposure system for cells grown on cover-slips was designed. The basic idea is to expose only a marked portion of the cover-slip to the magnetic field so that the effect of the ELF magnetic field on the cells grown on the same cover-slip can be observed under a microscope. A prototype system was built and tested. Experimental test results pertaining to the prototype system performance validate the proposed design approach. The paper concludes with a discussion of alternative approaches to the design of localized ELF magnetic field exposure systems.

  11. Shock front field structure in low-density systems

    NASA Astrophysics Data System (ADS)

    Hua, Rui; Mucguffey, Christopher; Beg, Farhat; Sio, Hong; Ping, Yuan; Wilks, Scott; Heeter, Bob; Collins, Rip

    2016-10-01

    It is known that a shock front is not a simple discontinuity in density and temperature as depicted in commonly used hydro codes but also consists of self-generated fields associated with gradients in the electron pressure. A quasi-planar platform using broadband proton radiography has been developed to study this field structure at a shock front. The broad bandwidth offers energy-dependent measurements which quantitatively constrain both the potential and field width at the shock front. Experiments were conducted on the OMEGA EP, where three long pulse beams delivered 6 kJ in 2 ns for shock initiation in a tube filled with either pure Helium or mixture of Helium and Neon, and a short pulse of 850 J, 10 ps generated broadband protons for point-projection radiography. Simultaneous spatially resolved soft-x-ray spectroscopy provided shock velocity, particle velocity and thermal emission measurements, constraining density and temperature for the field generation. The data and modeling indicate that a multi-KeV potential was present at the shock front where a strong electron pressure gradient existed. This work was performed under DOE contract DE-AC52-07NA27344 with support from OFES Early Career program and LLNL LDRD program.

  12. Field Trial of the Enhanced Data Authentication System (EDAS)

    SciTech Connect

    Thomas, Maikael A.; Baldwin, George T.; Hymel, Ross W.

    2016-05-01

    The goal of the field trial of EDAS was to demonstrate the utility of secure branching of operator instrumentation for nuclear safeguards, identify any unforeseen implementation and application issues with EDAS, and confirm whether the approach is compatible with operator concerns and constraints.

  13. Simple System to Measure the Earth's Magnetic Field

    ERIC Educational Resources Information Center

    Akoglu, R.; Halilsoy, M.; Mazharimousavi, S. Habib

    2010-01-01

    Our aim in this proposal is to use Faraday's law of induction as a simple lecture demonstration to measure the Earths magnetic field (B). This will also enable the students to learn about how electric power is generated from rotational motion. Obviously the idea is not original, yet it may be attractive in the sense that no sophisticated devices…

  14. BIOREMEDIATION IN THE FIELD SEARCH SYSTEM (BFSS) - USER DOCUMENTATION

    EPA Science Inventory

    The Bioremediation Field Initiative is a cooperative effort of the U.S. EPA's Office of Research and Development (ORD), Office of Solid Waste and Emergency Response (OSWER), and regional offices, and other federal agencies, state agencies, industry, and universities to ...

  15. Remote Laboratory and Animal Behaviour: An Interactive Open Field System

    ERIC Educational Resources Information Center

    Fiore, Lorenzo; Ratti, Giovannino

    2007-01-01

    Remote laboratories can provide distant learners with practical acquisitions which would otherwise remain precluded. Our proposal here is a remote laboratory on a behavioural test (open field test), with the aim of introducing learners to the observation and analysis of stereotyped behaviour in animals. A real-time video of a mouse in an…

  16. Optics design for Electron Cyclotron Emission Imaging system on J-TEXT

    NASA Astrophysics Data System (ADS)

    Ma, X. D.; Yang, Z. J.; Zhu, Y. L.; Pan, X. M.; Xiao, Y.; Ruan, B. W.; Zhuang, G.; Xie, J. L.

    2016-05-01

    An electron cyclotron emission imaging (ECEI) system is being developed for J-TEXT. It is comprised of two 16-channel antenna arrays that share the same toroidal window for the purpose of observing separate radial regions of the tokamak plasma simultaneously. Two imaging optic units have been designed, which share the same zoom lenses, but have different focus lenses. The setup is flexible and achieves good spatial resolution. In particular, the poloidal zoom factor can achieve 1.17 to 2.20. The desired focal plane can range anywhere from high field side (HFS) edge to low field side (LFS) edge. The effective field curvature adjustment (FCA) lenses have been adopted for the ECEI imaging optic system, which make the image plane flat enough to match the emission layer in order to increase the image quality.

  17. Particular transcendent solution of the Ernst system generalized on n fields

    SciTech Connect

    Leaute, B.; Marcilhacy, G.

    1986-03-01

    A particular solution, a function of a particular form of the fifth Painleve transcendent, of the Ernst system generalized to n fields is determined, which characterizes both the stationary axially symmetric fields, the solution of the Einstein (n-1) Maxwell equations, and one class of axially symmetric static self-dual SU(n+1) Yang--Mills fields.

  18. Field profiles of bulk plasmon polariton modes in layered systems containing a metamaterial.

    PubMed

    Bruno-Alfonso, A; Reyes-Gómez, E; Cavalcanti, S B; Oliveira, L E

    2012-02-01

    Electric and magnetic fields in a one-dimensional layered system that alternates air and a metamaterial are investigated. Special attention is devoted to frequencies of electric and magnetic bulk plasmons. It is shown that plasmon polaritons nearby such frequencies display field profiles concentrated in the metamaterial, where the field component parallel to the stacking direction is essentially uniform and dominates the perpendicular one.

  19. NMR system and method having a permanent magnet providing a rotating magnetic field

    DOEpatents

    Schlueter, Ross D [Berkeley, CA; Budinger, Thomas F [Berkeley, CA

    2009-05-19

    Disclosed herein are systems and methods for generating a rotating magnetic field. The rotating magnetic field can be used to obtain rotating-field NMR spectra, such as magic angle spinning spectra, without having to physically rotate the sample. This result allows magic angle spinning NMR to be conducted on biological samples such as live animals, including humans.

  20. Analysis of Uniformity of Magnetic Field Generated by the Two-Pair Coil System.

    PubMed

    Kędzia, P; Czechowski, T; Baranowski, M; Jurga, J; Szcześniak, E

    2013-05-01

    In this paper we use a simple analysis based on properties of the axial field generated by symmetrical multipoles to reveal all possible distributions of two coaxial pairs of circular windings, which result in systems featuring zero octupole and 32 pole magnetic moments (six-order systems). Homogeneity of magnetic field of selected systems is analyzed. It has been found that one of the derived systems generates homogenous magnetic field whose volume is comparable to that yielded by the eight-order system. The influence of the current distribution and the windings placement on the field homogeneity is considered. The table, graphs and equations given in the paper facilitate the choice of the most appropriate design for a given problem. The systems presented may find applications in low field electron paramagnetic resonance imaging, some functional f-MRI (nuclear magnetic resonance imaging) and bioelectromagnetic experiments requiring the access to the working space from all directions.

  1. Field Test of a DHW Distribution System: Temperature and Flow Analyses (Presentation)

    SciTech Connect

    Barley, C. D.; Hendron, B.; Magnusson, L.

    2010-05-13

    This presentation discusses a field test of a DHW distribution system in an occupied townhome. It includes measured fixture flows and temperatures, a tested recirculation system, evaluated disaggregation of flow by measured temperatures, Aquacraft Trace Wizard analysis, and comparison.

  2. Information on the metric system and related fields

    NASA Technical Reports Server (NTRS)

    Lange, E.

    1976-01-01

    This document contains about 7,600 references on the metric system and conversion to the metric system. These references include all known documents on the metric system as of December 1975, the month of enactment of the Metric Conversion Act of 1975. This bibliography includes books, reports, articles, presentations, periodicals, legislation, motion pictures, TV series, film strips, slides, posters, wall charts, education and training courses, addresses for information, and sources for metric materials and services. A comprehensive index is provided.

  3. Analysis Survey Report. Occupational Field 40 Data Systems.

    DTIC Science & Technology

    1984-01-01

    Since Marines from several OccFld 40 MOS’s perform teleprocessing tasks, an additional MOS is the appropriate method of identifying the unique tasks...TEST JCL 182. TEST PROCEDURE 183. DRAW LAYOUT OF SISTEM INPUTS/OUTPUTS 184. wRITE SYSTEM FLOiCHART 185. TEST SYSTEM (OUTGOING) 186. RELEASE SYSTEM...191, RESTORE DATA SET (LIBRARY) 23 . . * . 192. COMPRESS A LIBRARY PARTITICNED DATA SET (POSI 193. CREATE A BACKUP COPY OF A DATA SET CR LIBRARY PS

  4. Flight Set 360L006 STS-34 field joint protection system, thermal protection system, and systems tunnel components, volume 4

    NASA Technical Reports Server (NTRS)

    Wilkinson, J. P.

    1990-01-01

    The performance of the thermal protection system, field joint protection system, and systems tunnel components of Flight Set 360L006, are documented, as evaluated by postflight hardware inspection. The condition of both motors was similar to previous flights. Sixteen aft edge hits were noted on the ground environment instrumentation thermal protection system. Each hit left a clean substrate, indicating that the damage was caused by nozzle severance debris and/or water impact. No National Space and Transporation System debris criteria for missing thermal protection system were violated. One 5.0 by 1.0 in. unbond was observed on the left hand center field joint K5NA closeout and was elevated to an in-flight anomaly (STS-34-M-4) by the NASA Ice/Debris team. Aft edge damage to the K5NA and an associated black streak indicate that burning debris from the nozzle severance system was the likely cause of the damage. Minor divots caused by debris were seen on previous flights, but this is the first occurrence of a K5NA unbond. Since the unbond occurred after booster separation there is no impact on flight safety and no corrective actions was taken. The right hand center field joint primary heater failed the dielectric withstanding voltage test after joint closeout. The heater was then disabled by opening the circuit breaker, and the redundant heater was used. The redundant heater performed nominally during the launch countdown. A similar condition occurred on Flight 4 when a secondary joint heater failed the dielectric withstanding voltage test.

  5. Nonlinear Optical Systems Interacting with Amplitude-Modulated Optical Fields

    DTIC Science & Technology

    1990-07-01

    We start with the rate equations for the excited-state population of the laser transition p, d ( ltp = - (I + I + I,)P + -LI, (C.1) and the equation...spectroscopy; lasers ; parametric resonances ABSTRACT (Continue on reverse if necessary and identify by block number) Please see Abstract on Pages v-vi. I...he conducted research in the fields of modulation spectroscopy and laser instability under the guidance of Professor Carlos R. Stroud, Jr. While at

  6. Systemic Effects of Electromagnetic Fields in Patients with Myocardial Infarction

    NASA Astrophysics Data System (ADS)

    Cañedo-Dorantes, L.; Valle, L.; Uruchurtu, E.; Medel, A.; García-Mayen, F.; Serrano-Luna, G.

    2003-09-01

    Healing of acute myocardial infarction (AMI) is associated with inflammatory response, which promotes healing and scar formation. Activation of a local inflammatory response in patients with sequel of AMI could have an important role to enhance angiogenesis and regeneration of hibernating myocardial tissue. Chronic arterial leg ulcers have a similar etiology, and healing has been promoted by exposure to extremely low frequency electromagnetic fields (ELF). We report the evolution of three AMI patients with sequel of AMI that were exposed to ELF.

  7. Chemical Sanitation System for Pots and Pans in Field Operations

    DTIC Science & Technology

    1989-02-01

    DISHWASHING COMPOUNDS, DETERGENTS- WATER,- WATER CONSERVATION CLEANING, COLD WATER, LOW TEMPERATURE (over) 19. ABSTRACT (Continue on reverse if necessary and...Ingredients 21 v LIST OF ’ ES 1. cmmercial Products Tested 4 2. Sponge /Pads Testd 5 3. Meals Served at Field Test Site 9 4. Cleaning/Sanitizing Capability of...Adminstration (FDA) approval for incorpration into a disposable wipe or sponge /brush. In a similar study, conducted under a work unit entitled "Eating Utensil

  8. Circuitry, systems and methods for detecting magnetic fields

    DOEpatents

    Kotter, Dale K [Shelley, ID; Spencer, David F [Idaho Falls, ID; Roybal, Lyle G [Idaho Falls, ID; Rohrbaugh, David T [Idaho Falls, ID

    2010-09-14

    Circuitry for detecting magnetic fields includes a first magnetoresistive sensor and a second magnetoresistive sensor configured to form a gradiometer. The circuitry includes a digital signal processor and a first feedback loop coupled between the first magnetoresistive sensor and the digital signal processor. A second feedback loop which is discrete from the first feedback loop is coupled between the second magnetoresistive sensor and the digital signal processor.

  9. Highly efficient manipulation of Laplace fields in film system with structured bilayer composite.

    PubMed

    Lan, Chuwen; Lei, Ming; Bi, Ke; Li, Bo; Zhou, Ji

    2016-12-26

    Using metamaterials or transformation optics to manipulate Laplace fields, such as magnetic, electric and thermal fields, has become a research highlight. These studies, however, are usually limited to a bulk material system and to single field manipulation. In this paper, we focus on a film system and propose a general practical method applicable for such a system. In this method, the background film is covered with another one to construct a so-called "bilayer composite" to achieve required physical parameters. On the basis of the bilayer composite, a multi-physics cloak and a multi-physics concentrator for electric current and thermal flux are designed, fabricated, and demonstrated. This work provides an efficient way to control and manipulate single/ multi-physics Laplace fields like a dc electric field and a thermal field in a film system, which may find potential applications in IC technology, MEMS, and so on.

  10. Field test of a center pivot irrigation system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Uniformity of water distribution of a variable rate center pivot irrigation system was evaluated. This 4-span center pivot system was configured with 10 water application zones along its 233 m-long lateral. Two experiments were conducted for the uniformity tests. In one test, a constant water applic...

  11. Field Commissioning of a Daylight-Dimming Lighting System.

    ERIC Educational Resources Information Center

    Floyd, David B.; Parker, Danny S.

    A Florida elementary school cafeteria, retrofitted with a fluorescent lighting system that dims in response to available daylight, was evaluated through real time measurement of lighting and air conditioning power, work plane illumination, and interior/exterior site conditions. The new system produced a 27 percent reduction in lighting power due…

  12. Flow field description of the Space Shuttle Vernier reaction control system exhaust plumes

    NASA Technical Reports Server (NTRS)

    Cerimele, Mary P.; Alred, John W.

    1987-01-01

    The flow field for the Vernier Reaction Control System (VRCS) jets of the Space Shuttle Orbiter has been calculated from the nozzle throat to the far-field region. The calculations involved the use of recently improved rocket engine nozzle/plume codes. The flow field is discussed, and a brief overview of the calculation techniques is presented. In addition, a proposed on-orbit plume measurement experiment, designed to improve future estimations of the Vernier flow field, is addressed.

  13. Point sensitive NMR imaging system using a magnetic field configuration with a spatial minimum

    DOEpatents

    Eberhard, P.H.

    A point-sensitive NMR imaging system in which a main solenoid coil produces a relatively strong and substantially uniform magnetic field and a pair of perturbing coils powered by current in the same direction superimposes a pair of relatively weak perturbing fields on the main field to produce a resultant point of minimum field strength at a desired location in a direction along the Z-axis. Two other pairs of perturbing coils superimpose relatively weak field gradients on the main field in directions along the X- and Y-axes to locate the minimum field point at a desired location in a plane normal to the Z-axes. An rf generator irradiates a tissue specimen in the field with radio frequency energy so that desired nuclei in a small volume at the point of minimum field strength will resonate.

  14. Point sensitive NMR imaging system using a magnetic field configuration with a spatial minimum

    DOEpatents

    Eberhard, Philippe H.

    1985-01-01

    A point-sensitive NMR imaging system (10) in which a main solenoid coil (11) produces a relatively strong and substantially uniform magnetic field and a pair of perturbing coils (PZ1 and PZ2) powered by current in the same direction superimposes a pair of relatively weak perturbing fields on the main field to produce a resultant point of minimum field strength at a desired location in a direction along the Z-axis. Two other pairs of perturbing coils (PX1, PX2; PY1, PY2) superimpose relatively weak field gradients on the main field in directions along the X- and Y-axes to locate the minimum field point at a desired location in a plane normal to the Z-axes. An RF generator (22) irradiates a tissue specimen in the field with radio frequency energy so that desired nuclei in a small volume at the point of minimum field strength will resonate.

  15. Intelligent fiber sensing system for the oil field area

    NASA Astrophysics Data System (ADS)

    Sun, Wenju; Ma, Linping

    2010-08-01

    Optical Fiber strain sensor using fiber Bragg grating are poised to play a major role in structural health from military to civil engineering. Fiber Bragg Grating sensor is a practical type of fiber optic sensors. Its measurement is encoded with the wavelength of the optical signal reflected from fiber Bragg grating. The method of measuring the absolute optical wavelength is a critical component of the fiber optic sensing system. To reliably detect very small changes in the environment at the sensor, the interrogation system must provide accurate and repeatable wavelength measurements. Energy sources are increasingly scarce in the world. Getting oil from the oil-wells has become more and more difficult. Therefore, new technology to monitor the oil-well condition has become extremely important. The traditional electrical sensor system is no longer useful because of the down-hole's high temperature and high pressure environment. The optical fiber sensing system is the first choice to monitor this condition. This system will reduce the cost and increase the productivity. In the high pressure and high temperature environment, the traditional packed fiber grating pressure-temperature sensor will be no longer reliability. We have to find a new fiber grating temperature-pressure sensor element and the interrogation system. In this work we use the very narrow bandwidth birefringent fiber grating as the sensing element. We obtain the interrogation system has 0.1 pm resolution.

  16. Man-portable command, communication, and control systems for the next generation of unmanned field systems

    NASA Astrophysics Data System (ADS)

    Jacobus, Charles J.; Mitchell, Brian T.; Jacobus, Heidi N.; Watts, Russell C.; Taylor, Mark J.; Salazar, Alfonso

    1993-05-01

    New generations of military unmanned systems on the ground, at sea, and in the air will be driven by man-portable command units. In past efforts we implemented several prototypes of such units which provided display and capture of up to four video input channels, provided 4 color LCD screens and a larger status display LCD screen, provided drive input through two joysticks, and, through software, supported a flexible 'virtual' driver's interface. We have also performed additional trade analysis of prototype systems incorporating force feedback and extensive image-oriented processing facilities applied to man-controlled robotic control systems. This prior work has resulted in a database of practical design guidelines and a new generation of hardened compact robotic command center which is being designed and built to provide more advanced video capture, display, and interfacing features, supercomputer level computational performance, and ergonomic features for hard field use. In this paper we will summarize some past work and will project current performance to features likely to be common across most unmanned systems command, control, and communications subsystems of the near future.

  17. Grounding system analysis in transients programs applying electromagnetic field approach

    SciTech Connect

    Heimbach, M.; Grcev, L.D.

    1997-01-01

    Lightning protection studies of substations and power systems require knowledge of the dynamic behavior of large grounding grids during electromagnetic transients. This paper presents strategies which allow to incorporate complex grounding structures computed using a rigorous electromagnetic model in transients programs. A novel technique for rational function representation of frequency-dependent grounding system impedances in the EMTP is described. An arbitrary number of feeding points can be modeled as mutual coupling is taken into account. Overvoltages throughout electrical power systems and the transient ground potential rise in the surroundings of grounding structures can be computed.

  18. Field investigation of FGD system chemistry. Final report

    SciTech Connect

    Litherland, S.T.; Colley, J.D.; Glover, R.L.; Maller, G.; Behrens, G.P.

    1984-12-01

    Three full-scale wet limestone FGD systems were investigated to gain a better understanding of FGD system operation and chemistry. The three plants which participated in the program were South Mississippi Electric Power Association's R. D. Morrow Station, Colorado-Ute Electric Association's Craig Station, and Central Illinois Light Company's Duck Creek Station. Each FGD system was characterized with respect to SO/sub 2/ removal, liquid and solid phase chemistry, and calcium sulfite and calcium sulfate relative saturation. Mist eliminator chemistry and performance were documented at Morrow and Duck Creek. Solutions to severe mist eliminator scaling and pluggage were demonstrated at Duck Creek. A technical and econ

  19. Field demonstrations of communication systems for distribution automation

    NASA Astrophysics Data System (ADS)

    Rhyne, V. T.

    1982-06-01

    Communication systems for distribution automation and load management were developed. This program included three power line carrier projects, an ultra high frequency radio project, and a telephone project. For each project, a two way (half duplex) digital communication system was developed to perform such functions as fault location and isolation, distribution feeder switching, load control, time of day metering, remote meter reading, and equipment monitoring. Most of these demonstration projects were subject to hardware failures and schedule slippages, but when the data pertinent to the two way communications performance of the operational portions of each system were examined, performance at or above an 80% success rate was measured in all projects. These results support the conclusion that each of these communications systems can satisfy utility requirements for distribution automation, load control and remote meter reading.

  20. Field Demonstration of Condition Assessment Technologies for Wastewater Collection Systems

    EPA Science Inventory

    Reliable information on pipe condition is needed to accurately estimate the remaining service life of wastewater collection system assets. Although inspections with conventional closed-circuit television (CCTV) have been the mainstay of pipeline condition assessment for decades,...

  1. Magnetic fields in mixed neutron-star-plus-wormhole systems

    SciTech Connect

    Aringazin, Ascar; Dzhunushaliev, Vladimir; Folomeev, Vladimir; Kleihaus, Burkhard; Kunz, Jutta E-mail: v.dzhunushaliev@gmail.com E-mail: b.kleihaus@uni-oldenburg.de

    2015-04-01

    We consider mixed configurations consisting of a wormhole filled by a strongly magnetized isotropic or anisotropic neutron fluid. The nontrivial topology of the spacetime is allowed by the presence of exotic matter. By comparing these configurations with ordinary magnetized neutron stars, we clarify the question of how the presence of the nontrivial topology influences the magnetic field distribution inside the fluid. In the case of an anisotropic fluid, we find new solutions describing configurations, where the maximum of the fluid density is shifted from the center. A linear stability analysis shows that these mixed configurations are unstable.

  2. Wide field of view adaptive optical system for lightweight deployable telescope technologies

    NASA Astrophysics Data System (ADS)

    McComas, Brian K.; Cermak, Michael A.; Friedman, Edward J.

    2003-02-01

    A NASA research contract (NAS1-00116) was awarded to Ball Aerospace & Technologies Corp. in January 2000 to study wide field-of-view adaptive optical systems. These systems will be required on future high resolution Earth remote sensing systems that employ large, flexible, lightweight, deployed primary mirrors. The deformations from these primary mirrors will introduce aberrations into the optical system, which must be removed by corrective optics. For economic reasons, these remote sensing systems must have a large field-of-view (a few degrees). Unlike ground-based adaptive optical systems, which have a negligible field-of-view, the adaptive optics on these space-based remote sensing systems will be required to correct for the deformations in the primary mirror over the entire field-of-view. A new error function, which is an enhancement to conventional adaptive optics, for wide field-of-view optical systems will be introduced. This paper will present the goals of the NASA research project and its progress. The initial phase of this research project is a demonstration of the wide field-of-view adaptive optics theory. A breadboard has been designed and built for this purpose. The design and assembly of the breadboard will be presented, along with the final results for this phase of the research project. Finally, this paper will show the applicability of wide field-of-view adaptive optics to space-based astronomical systems.

  3. Field trial of the enhanced data authentication system (EDAS)

    SciTech Connect

    Thomas, Maikael A.; Hymel, Ross W.; Baldwin, George; Smejkal, Andreas; Linnebach, Ralf

    2016-11-01

    The Enhanced Data Authentication System (EDAS) is means to securely branch information from an existing measurement system or data stream to a secondary observer. In an international nuclear safeguards context, the EDAS connects to operator instrumentation, and provides a cryptographically secure copy of the information for a safeguards inspectorate. However, this novel capability could be a valuable complement to inspector-owned safeguards instrumentation, offering context that is valuable for anomaly resolution and contingency.

  4. Field Testing of a Pneumatic Regolith Feed System During a 2010 ISRU Field Campaign on Mauna Kea, Hawaii

    NASA Technical Reports Server (NTRS)

    Craft, Jack; Zacny, Kris; Chu, Philip; Wilson, Jack; Santoro, Chris; Carlson, Lee; Maksymuk, Michael; Townsend, Ivan I.; Mueller, Robert P.; Mantovani, James G.

    2010-01-01

    Lunar In Situ Resource Utilization (ISRU) consists of a number of tasks starting with mining of lunar regolith, followed by the transfer of regolith to an oxygen extraction reactor and finally processing the regolith and storing of extracted oxygen. The transfer of regolith from the regolith hopper at the ground level to an oxygen extraction reactor many feet above the surface could be accomplished in different ways, including using a mechanical auger, bucket ladder system or a pneumatic system. The latter system is commonly used on earth when moving granular materials since it offers high reliability and simplicity of operation. In this paper, we describe a pneumatic regolith feed system, delivering feedstock to a Carbothermal reactor and lessons learned from deploying the system during the 2010 ISRU field campaign on the Mauna Kea, Hawaii.

  5. Phenotyping for the dynamics of field wheat root system architecture

    NASA Astrophysics Data System (ADS)

    Chen, Xinxin; Ding, Qishuo; Błaszkiewicz, Zbigniew; Sun, Jiuai; Sun, Qian; He, Ruiyin; Li, Yinian

    2017-01-01

    We investigated a method to quantify field-state wheat RSA in a phenotyping way, depicting the 3D topology of wheat RSA in 14d periods. The phenotyping procedure, proposed for understanding the spatio-temporal variations of root-soil interaction and the RSA dynamics in the field, is realized with a set of indices of mm scale precision, illustrating the gradients of both wheat root angle and elongation rate along soil depth, as well as the foraging potential along the side directions. The 70d was identified as the shifting point distinguishing the linear root length elongation from power-law development. Root vertical angle in the 40 mm surface soil layer was the largest, but steadily decreased along the soil depth. After 98d, larger root vertical angle appeared in the deep soil layers. PAC revealed a stable root foraging potential in the 0–70d period, which increased rapidly afterwards (70–112d). Root foraging potential, explained by MaxW/MaxD ratio, revealed an enhanced gravitropism in 14d period. No-till post-paddy wheat RLD decreased exponentially in both depth and circular directions, with 90% roots concentrated within the top 20 cm soil layer. RER along soil depth was either positive or negative, depending on specific soil layers and the sampling time.

  6. Phenotyping for the dynamics of field wheat root system architecture

    PubMed Central

    Chen, Xinxin; Ding, Qishuo; Błaszkiewicz, Zbigniew; Sun, Jiuai; Sun, Qian; He, Ruiyin; Li, Yinian

    2017-01-01

    We investigated a method to quantify field-state wheat RSA in a phenotyping way, depicting the 3D topology of wheat RSA in 14d periods. The phenotyping procedure, proposed for understanding the spatio-temporal variations of root-soil interaction and the RSA dynamics in the field, is realized with a set of indices of mm scale precision, illustrating the gradients of both wheat root angle and elongation rate along soil depth, as well as the foraging potential along the side directions. The 70d was identified as the shifting point distinguishing the linear root length elongation from power-law development. Root vertical angle in the 40 mm surface soil layer was the largest, but steadily decreased along the soil depth. After 98d, larger root vertical angle appeared in the deep soil layers. PAC revealed a stable root foraging potential in the 0–70d period, which increased rapidly afterwards (70–112d). Root foraging potential, explained by MaxW/MaxD ratio, revealed an enhanced gravitropism in 14d period. No-till post-paddy wheat RLD decreased exponentially in both depth and circular directions, with 90% roots concentrated within the top 20 cm soil layer. RER along soil depth was either positive or negative, depending on specific soil layers and the sampling time. PMID:28079107

  7. 47 CFR 90.359 - Field strength limits for EA-licensed LMS systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... systems. 90.359 Section 90.359 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Intelligent Transportation Systems Radio Service § 90.359 Field strength limits for EA-licensed LMS systems. EA-licensed multilateration systems...

  8. Integrated Design System of Toroidal Field Coil for CFETR

    NASA Astrophysics Data System (ADS)

    Luo, Zhiren; Liu, Xufeng; Du, Shuangsong; Wang, Zhongwei; Song, Yuntao

    2016-09-01

    Integrating engineering software is meaningful but challenging for a system code of a fusion device. This issue is seldom considered by system codes currently. Therefore, to discuss the issue, the Integrated Design System of TF Coil (IDS-TFC) has been worked out, which consists of physical calculation, CAD, and Finite Element Analysis (FEA). Furthermore, an Integrated and Automatically Optimized Method (IAOM) has been created to address the integration and interfaces. The method utilizes a geometry parameter to connect each design submodule and achieve automatic optimization. Double-objectives optimization has been realized, confirming it is feasible to integrate and optimize engineering design and physical calculation. Moreover, IDS-TFC can also serve as a useful reference of integrated design processing for subsequent fusion design. supported by the National Magnetic Confinement Fusion Science Program of China (Nos. 2014GB110000, 2014GB110002)

  9. Optimizing the optical field distribution of near-field SIL optical storage system using five-zone binary phase filters

    NASA Astrophysics Data System (ADS)

    Fang, Chaolong; Zhang, Yaoju; Zhu, Haiyong

    2012-06-01

    Five-zone binary phase filters (FBPFs) are proposed for decreasing the spot size and/or increasing the focal depth of the near-field optical storage system with a hemisphere solid immersion lens (SIL). The design of filters is based on the vector diffraction theory and the MATLAB optimizing toolbox. Three FBPFs with rotationally symmetrical pupil function have been designed, where the one FBPF is for increasing the focal depth as big as possible, the second FBPF is for improving the resolution as high as possible, and the third FBPF integrate the increase of focal depth with the improvement of resolution. Numerical results show that compared with the three-zone amplitude filter, the designed five-zone binary phase-only filters have more prominent performances in improving the focal depth and the resolution of the near-field SIL optical storage system.

  10. Design and field performance of the KENETECH photovoltaic inverter system

    SciTech Connect

    Behnke, M.R.

    1995-11-01

    KENETECH Windpower has recently adapted the power conversion technology developed for the company`s variable speed wind turbine to grid-connected photovoltaic applications. KENETECH PV inverter systems are now in successful operation at the Sacramento Municipal Utility District`s (SMUD) Hedge Substation and the PVUSA-Davis site, with additional systems scheduled to be placed into service by the end of 1995 at SMUD, the New York Power Authority, Xerox Corporation`s Clean Air Now project, and the Georgia Tech Aquatic Center. The features of the inverter are described.

  11. Experience with wavefront sensor and deformable mirror interfaces for wide-field adaptive optics systems

    NASA Astrophysics Data System (ADS)

    Basden, A. G.; Atkinson, D.; Bharmal, N. A.; Bitenc, U.; Brangier, M.; Buey, T.; Butterley, T.; Cano, D.; Chemla, F.; Clark, P.; Cohen, M.; Conan, J.-M.; de Cos, F. J.; Dickson, C.; Dipper, N. A.; Dunlop, C. N.; Feautrier, P.; Fusco, T.; Gach, J. L.; Gendron, E.; Geng, D.; Goodsell, S. J.; Gratadour, D.; Greenaway, A. H.; Guesalaga, A.; Guzman, C. D.; Henry, D.; Holck, D.; Hubert, Z.; Huet, J. M.; Kellerer, A.; Kulcsar, C.; Laporte, P.; Le Roux, B.; Looker, N.; Longmore, A. J.; Marteaud, M.; Martin, O.; Meimon, S.; Morel, C.; Morris, T. J.; Myers, R. M.; Osborn, J.; Perret, D.; Petit, C.; Raynaud, H.; Reeves, A. P.; Rousset, G.; Sanchez Lasheras, F.; Sanchez Rodriguez, M.; Santos, J. D.; Sevin, A.; Sivo, G.; Stadler, E.; Stobie, B.; Talbot, G.; Todd, S.; Vidal, F.; Younger, E. J.

    2016-06-01

    Recent advances in adaptive optics (AO) have led to the implementation of wide field-of-view AO systems. A number of wide-field AO systems are also planned for the forthcoming Extremely Large Telescopes. Such systems have multiple wavefront sensors of different types, and usually multiple deformable mirrors (DMs). Here, we report on our experience integrating cameras and DMs with the real-time control systems of two wide-field AO systems. These are CANARY, which has been operating on-sky since 2010, and DRAGON, which is a laboratory AO real-time demonstrator instrument. We detail the issues and difficulties that arose, along with the solutions we developed. We also provide recommendations for consideration when developing future wide-field AO systems.

  12. Interpretation of experimental results on Kondo systems with crystal field.

    PubMed

    Romero, M A; Aligia, A A; Sereni, J G; Nieva, G

    2014-01-15

    We present a simple approach to calculate the thermodynamic properties of single Kondo impurities including orbital degeneracy and crystal field effects (CFE) by extending a previous proposal by Schotte and Schotte (1975 Phys. Lett. 55A 38). Comparison with exact solutions for the specific heat of a quartet ground state split into two doublets shows deviations below 10% in the absence of CFE and a quantitative agreement for moderate or large CFE. As an application, we fit the measured specific heat of the compounds CeCu2Ge2, CePd3Si0.3, CePdAl, CePt, Yb2Pd2Sn and YbCo2Zn20. The agreement between theory and experiment is very good or excellent depending on the compound, except at very low temperatures due to the presence of magnetic correlations (not accounted for in the model).

  13. Progress on the C-Mod FIR Polarimeter System

    NASA Astrophysics Data System (ADS)

    Xu, P.; Irby, J. H.; Bergerson, W. F.; Brower, D. L.; Ding, W. X.; Shiraiwa, S.; Wolfe, S.

    2010-11-01

    A poloidally viewing FIR polarimetry diagnostic is being developed for the Alcator C-Mod Tokamak. The primary diagnostic components are a two-wave FIR laser at 117.73 microns and newly developed detectors whose performance characteristics will be described. Faraday rotation will be used both to refine the q-profile measurement by adding constraints to EFIT , and to study density and magnetic field fluctuations. A three-chord system has been installed, one chord of which is being tested during the FY10 C-Mod campaign. The FIR laser source is affected by both stray magnetic fields and mechanical vibrations present in the experimental cell thereby impacting the measurement. Methods developed to mitigate and correct for these effects will be discussed. Initial Faraday data will be compared with expectations from numerical simulation.

  14. Field performance of an acoustic scour-depth monitoring system

    USGS Publications Warehouse

    Mason, Jr., Robert R.; Sheppard, D. Max

    1994-01-01

    The Herbert C. Bonner Bridge over Oregon Inlet serves as the only land link between Bodie and Hatteras Islands, part of the Outer Banks of North Carolina. Periodic soundings over the past 30 years have documented channel migration, local scour, and deposition at several pilings that support the bridge. In September 1992, a data-collection system was installed to permit the off-site monitoring of scour at 16 bridge pilings. The system records channel-bed elevations at 15-minute intervals and transmits the data to a satellite receiver. A cellular phone connection also permits downloading and reviewing of the data as they are being collected. A digitally recording, acoustic fathometer is the main component of the system. In November 1993, current velocity, water-surface elevation, wave characteristics, and water temperature measuring instruments were also deployed at the site. Several performance problems relating to the equipment and to the harsh marine environment have not been resolved, but the system has collected and transmitted reliable scour-depth and water-level data.

  15. A Field Study Training Program on Wastewater Lagoon Systems.

    ERIC Educational Resources Information Center

    Water and Wastewater Technical School, Neosho, MO.

    This publication is a text and reference manual for operating personnel of both large and small wastewater lagoon systems with support from the Environmental Protection Agency (EPA). As a text, this inservice training manual is intended to be used in a correspondence course wherein the trainee or operator would read and study each chapter before…

  16. FIELD TEST OF THE PROPOSED REVISED HAZARD RANKING SYSTEM (HRS)

    EPA Science Inventory

    The Superfund Amendments and Reauthorization Act of 1986 (SARA) requires the U.S. Environmental Protection Agency (EPA) to revise the Hazard Ranking System (HRS) so that, to the maximum extent feasible, it accurately assesses the relative risks associated with actual or potent...

  17. ANOLE Portable Radiation Detection System Field Test and Evaluation Campaign

    SciTech Connect

    Chris A. Hodge

    2007-07-12

    Handheld, backpack, and mobile sensors are elements of the Global Nuclear Detection System for the interdiction and control of illicit radiological and nuclear materials. They are used by the U.S. Department of Homeland Security (DHS) and other government agencies and organizations in various roles for border protection, law enforcement, and nonproliferation monitoring. In order to systematically document the operational performance of the common commercial off-the-shelf portable radiation detection systems, the DHS Domestic Nuclear Detection Office conducted a test and evaluation campaign conducted at the Nevada Test Site from January 18 to February 27, 2006. Named “Anole,” it was the first test of its kind in terms of technical design and test complexities. The Anole test results offer users information for selecting appropriate mission-specific portable radiation detection systems. The campaign also offered manufacturers the opportunity to submit their equipment for independent operationally relevant testing to subsequently improve their detector performance. This paper will present the design, execution, and methodologies of the DHS Anole portable radiation detection system test campaign.

  18. Interaction of biological systems with static and ELF electric and magnetic fields

    SciTech Connect

    Anderson, L.E.; Kelman, B.J.; Weigel, R.J.

    1987-01-01

    Although background levels of atmospheric electric and geomagnetic field levels are extremely low, over the past several decades, human beings and other life forms on this planet have been subjected to a dramatically changing electromagnetic milieu. An exponential increase in exposure to electromagnetic fields has occurred, largely because of such technological advances as the growth of electrical power generation and transmission systems, the increased use of wireless communications, and the use of radar. In addition, electromagnetic field generating devices have proliferated in industrial plants, office buildings, homes, public transportation systems, and elsewhere. Although significant increases have occurred in electromagnetic field strenghths spanning all frequency ranges, this symposium addresses only the impact of these fields at static and extremely low frequencies (ELF), primarily 50 and 60 Hz. This volume contains the proceedings of the symposium entitled /open quotes/Interaction of biological systems with static and ELF electric and magnetic fields/close quotes/. The purpose of the symposium was to provide a forum for discussions of all aspects of research on the interaction of static and ELF electromagnetic fields with biological systems. These systems include simple biophysical models, cell and organ preparations, whole animals, and man. Dosimetry, exposure system design, and artifacts in ELF bioeffects research were also addressed, along with current investigations that examine fundamental mechanisms of interactions between the fields and biological processes. Papers are indexed separately.

  19. Tomographic systems for the Helmholtz equation with extended Born field models using conjugate gradient inversion methods

    NASA Astrophysics Data System (ADS)

    Olsen, Scott Charles

    In this dissertation, new inverse scattering algorithms are derived for the Helmholtz equation using the Extended Born field model (eikonal rescattered field), and the angular spectrum (parabolic) layered field model. These two field models performed the 'best' of all the field models evaluated. Algorithms are solved with conjugate gradient methods. An advanced ultrasonic data acquisition system is also designed. Many different field models for use in a reconstruction algorithm are investigated. 'Layered' field models that mathematically partition the field calculation in layers in space possess the advantage that the field in layer n is calculated from the field in layer n - 1. Several of the 'layered' field models are investigated in terms of accuracy and computational complexity. Field model accuracy using field rescattering is also tested. The models investigated are the eikonal field model, the angular spectrum (AS) field model, and the parabolic field models known as the Split-Step Fast-Fourier Transform and the Crank-Nicolson algorithms. All of the 'layered' field models can be referred to as Extended Born field models since the 'layered' field models are more accurate than the Born approximated total field. The Rescattered Extended Born (eikonal rescattered field) Transmission Mode (REBTM) algorithm with the AS field model and the Nonrescattered AS Reconstruction (NASR) algorithm are tested with several types of objects: a single-layer cylinder, double-layer cylinders, two double-layer cylinders and the breast model. Both algorithms, REBTM and NASR work well; however, the NASR algorithm is faster and more accurate than the REBTM algorithm. The NASR algorithm is matched well with the requirements of breast model reconstructions. A major purpose of new scanner development is to collect both transmission and reflection data from multiple ultrasonic transducer arrays to test the next generation of reconstruction algorithms. The data acquisition system advanced

  20. Intense-field-stimulated multiphoton transitions in a two-level system

    SciTech Connect

    Milman, Perola; Zagury, Nicim

    2011-11-15

    We study the interaction of an intense classical field with a two-level system coupled to a bosonic quantized field. We focus on the regime where the classical field and the two-level system characteristic frequencies are the same, while the quantized mode is set off resonance with both. We show that a parameter governing the dynamics of the system is the ratio between the classical field's intensity and the quantized mode detuning. Depending on this parameter, multiple excitations can be created in the quantized mode in a single cycle of the two-level system. Examples of physical setups allowing for the application of the presented ideas are superconducting circuits in strip-line resonators, laser cooled trapped ions, and neutral atoms coupled to the quantized field of a cavity. We focus on the latter in order to show that, with realistic experimental parameters, it is possible to generate up to four photons in a single Rabi cycle.

  1. Magnetic field uniformity of the practical tri-axial Helmholtz coils systems.

    PubMed

    Beiranvand, R

    2014-05-01

    In this paper, effects of the assembly misalignments and the manufacturing mismatches on the magnetic field uniformity of a practical tri-axial Helmholtz coils system have been modeled mathematically. These undesired effects regularly occur in any practical tri-axial Helmholtz coils system. To confirm the mathematical calculations, a tri-axial Helmholtz coils system has been constructed and the uniformity of its magnetic field has been measured under different conditions. The experimental results are in good agreement with the mathematical analyses.

  2. General properties of quantum optical systems in a strong field limit

    NASA Technical Reports Server (NTRS)

    Chumakov, S. M.; Klimov, Andrei B.

    1994-01-01

    We investigate the dynamics of an arbitrary atomic system (n-level atoms or many n-level atoms) interacting with a resonant quantized mode of an em field. If the initial field state is a coherent state with a large photon number then the system dynamics possesses some general features, independently of the particular structure of the atomic system. Namely, trapping states, factorization of the wave function, collapses and revivals of the atomic energy oscillations are discussed.

  3. Electric field divertor plasma pump

    DOEpatents

    Schaffer, M.J.

    1994-10-04

    An electric field plasma pump includes a toroidal ring bias electrode positioned near the divertor strike point of a poloidal divertor of a tokamak, or similar plasma-confining apparatus. For optimum plasma pumping, the separatrix of the poloidal divertor contacts the ring electrode, which then also acts as a divertor plate. A plenum or other duct near the electrode includes an entrance aperture open to receive electrically-driven plasma. The electrode is insulated laterally with insulators, one of which is positioned opposite the electrode at the entrance aperture. An electric field E is established between the ring electrode and a vacuum vessel wall, with the polarity of the bias applied to the electrode being relative to the vessel wall selected such that the resultant electric field E interacts with the magnetic field B already existing in the tokamak to create an E [times] B/B[sup 2] drift velocity that drives plasma into the entrance aperture. The pumped plasma flow into the entrance aperture is insensitive to variations, intentional or otherwise, of the pump and divertor geometry. Pressure buildups in the plenum or duct connected to the entrance aperture in excess of 10 mtorr are achievable. 11 figs.

  4. Electric field divertor plasma pump

    DOEpatents

    Schaffer, Michael J.

    1994-01-01

    An electric field plasma pump includes a toroidal ring bias electrode (56) positioned near the divertor strike point of a poloidal divertor of a tokamak (20), or similar plasma-confining apparatus. For optimum plasma pumping, the separatrix (40) of the poloidal divertor contacts the ring electrode (56), which then also acts as a divertor plate. A plenum (54) or other duct near the electrode (56) includes an entrance aperture open to receive electrically-driven plasma. The electrode (56) is insulated laterally with insulators (63,64), one of which (64) is positioned opposite the electrode at the entrance aperture. An electric field E is established between the ring electrode (56) and a vacuum vessel wall (22), with the polarity of the bias applied to the electrode being relative to the vessel wall selected such that the resultant electric field E interacts with the magnetic field B already existing in the tokamak to create an E.times.B/B.sup.2 drift velocity that drives plasma into the entrance aperture. The pumped plasma flow into the entrance aperture is insensitive to variations, intentional or otherwise, of the pump and divertor geometry. Pressure buildups in the plenum or duct connected to the entrance aperture in excess of 10 mtorr are achievable.

  5. Influence of an electric field on the ferromagnetic resonance in a plane-layered magnetic system

    NASA Astrophysics Data System (ADS)

    Karashtin, E. A.; Fraerman, A. A.

    2016-11-01

    The influence of an electric field on the ferromagnetic resonance (FMR) in a multilayer magnetic system consisting of two magnetic layers separated by a thin nonmagnetic interlayer has been investigated. It has been shown that, upon the excitation of magnetization oscillations by a microwave magnetic field, the eigenfrequencies of the ferromagnetic resonance depend on the stationary electric field applied in the plane of the layers. It has also been demonstrated that, in this system, high-frequency magnetization oscillations can be excited by an electric microwave field. The results of the investigation of the polarization properties of the excitation mechanism indicate that this effect can be observed experimentally.

  6. Directional x-ray dark-field imaging of strongly ordered systems

    SciTech Connect

    Jensen, Torben Haugaard; Feidenhans'l, Robert; Bech, Martin; Pfeiffer, Franz; Zanette, Irene; Weitkamp, Timm; David, Christian; Rutishauser, Simon; Deyhle, Hans; Reznikova, Elena; Mohr, Juergen

    2010-12-01

    Recently a novel grating based x-ray imaging approach called directional x-ray dark-field imaging was introduced. Directional x-ray dark-field imaging yields information about the local texture of structures smaller than the pixel size of the imaging system. In this work we extend the theoretical description and data processing schemes for directional dark-field imaging to strongly scattering systems, which could not be described previously. We develop a simple scattering model to account for these recent observations and subsequently demonstrate the model using experimental data. The experimental data includes directional dark-field images of polypropylene fibers and a human tooth slice.

  7. System and method for magnetic current density imaging at ultra low magnetic fields

    SciTech Connect

    Espy, Michelle A.; George, John Stevens; Kraus, Robert Henry; Magnelind, Per; Matlashov, Andrei Nikolaevich; Tucker, Don; Turovets, Sergei; Volegov, Petr Lvovich

    2016-02-09

    Preferred systems can include an electrical impedance tomography apparatus electrically connectable to an object; an ultra low field magnetic resonance imaging apparatus including a plurality of field directions and disposable about the object; a controller connected to the ultra low field magnetic resonance imaging apparatus and configured to implement a sequencing of one or more ultra low magnetic fields substantially along one or more of the plurality of field directions; and a display connected to the controller, and wherein the controller is further configured to reconstruct a displayable image of an electrical current density in the object. Preferred methods, apparatuses, and computer program products are also disclosed.

  8. Non-linear optics of coupled quantum dots and atomic systems with coherent control fields

    NASA Astrophysics Data System (ADS)

    Mumba, Mambwe

    Presented herein is an investigation of quantum systems with coherent optical control fields. Three such systems are examined. The first consists of two dipole-dipole coupled quantum dots or dimers which behave as an effective three or four-level system whose susceptibility and hence transmissivity for an optical beam at some frequency may be switched on or off in response to a coherent control field. The second quantum system consists of a model cluster of three coupled dots that is shown to display light intermittency or blinking when irradiated by a coherent field. Results indicate that the observed variation in rate, intensity and duration of blinking times occasioned by the rare but observable rapid blinking at higher rate and intensity (superradiance) can be traced back to the groupings of states in different manifolds that the coupled system is capable of being found in at any given time. It is shown, however, that the experimentally observed blinking can not be entirely accounted for by dipole-dipole coupling alone. The third system investigated consists of Rubidium atoms in a cell placed in a ring cavity. A coherent control field drives the system. A mathematical model of the system is developed which consists of propagating a gaussian beam around the system and examining the output spectrum when a steady state value of the electromagnetic field is attained in the Rubidium cell. Some interesting features occurring in the output spectrum of the field at some cavity detuning are reproduced and match those experimentally observed.

  9. Training Field Grade Officers to Exploit the Maneuver Control System

    DTIC Science & Technology

    2007-11-02

    9 Peter F. Drucker , The Effective Executive (New York: Harper and Row 1966), 1. 10 “Chapter 5: Battle Command,” “US Army Combined Arms Command...digital battlefield systems. Peter Drucker , in his book The Effective Executive, identifies five “habits” characteristic of the effective executive...of decisions that include bad ones.16 16 Drucker , The Effective Executive, 23-24, 113 14 The

  10. Field Artillery Cannon Weapons Systems and Ammunition Handbook.

    DTIC Science & Technology

    1983-02-01

    hydropneumatic liquid and indicates that the mechanisim. employs a liquid; gas principle of checking recoil and returning the the liquid used is re,’oii oil ...Recoil oil is a tube to battery. Recoil was checked primarily by petroleum-base hydraulic fluid. "I "eum". the throttling of oil , and the tube was...controlled by the flow )f the recoil oil through increasing the rate, of fire. With the priinitive certain throttling devices of the recoi. system, the

  11. Extended depth of field system for long distance iris acquisition

    NASA Astrophysics Data System (ADS)

    Chen, Yuan-Lin; Hsieh, Sheng-Hsun; Hung, Kuo-En; Yang, Shi-Wen; Li, Yung-Hui; Tien, Chung-Hao

    2012-10-01

    Using biometric signatures for identity recognition has been practiced for centuries. Recently, iris recognition system attracts much attention due to its high accuracy and high stability. The texture feature of iris provides a signature that is unique for each subject. Currently most commercial iris recognition systems acquire images in less than 50 cm, which is a serious constraint that needs to be broken if we want to use it for airport access or entrance that requires high turn-over rate . In order to capture the iris patterns from a distance, in this study, we developed a telephoto imaging system with image processing techniques. By using the cubic phase mask positioned front of the camera, the point spread function was kept constant over a wide range of defocus. With adequate decoding filter, the blurred image was restored, where the working distance between the subject and the camera can be achieved over 3m associated with 500mm focal length and aperture F/6.3. The simulation and experimental results validated the proposed scheme, where the depth of focus of iris camera was triply extended over the traditional optics, while keeping sufficient recognition accuracy.

  12. The Magnetic Field Structure of a Snowflake Divertor

    SciTech Connect

    Ryutov, D D; Cohen, R H; Rognlien, T D; Umansky, M V

    2008-05-30

    The snowflake divertor exploits a tokamak geometry in which the poloidal magnetic field null approaches second order; the name stems from the characteristic hexagonal, snowflake-like, shape of the separatrix for an exact second-order null. The proximity of the poloidal field structure to that of a second-order null substantially modifies edge magnetic properties compared to the standard X-point geometry; this, in turn, affects the edge plasma behavior. Modifications include: (1) The flux expansion near the null-point becomes 2-3 times larger; (2) The connection length between the equatorial plane and divertor plate significantly increases; (3) Magnetic shear just inside the separatrix becomes much larger; and (4) In the open-field-line region, the squeezing of the flux-tubes near the null-point increases, thereby causing stronger decoupling of the plasma turbulence in the divertor legs and in the main SOL. These effects can be used to reduce the power load on the divertor plates and/or to suppress the 'bursty' component of the heat flux. It is emphasized that the snowflake divertor can be created by a relatively simple set of poloidal field coils situated beyond the toroidal field coils. Analysis of the robustness of the proposed divertor configuration with respect to changes of the plasma current distribution is presented and it is concluded that, even if the null is close to the second order, the configuration is quite robust.

  13. Modelling Mass Casualty Decontamination Systems Informed by Field Exercise Data

    PubMed Central

    Egan, Joseph R.; Amlôt, Richard

    2012-01-01

    In the event of a large-scale chemical release in the UK decontamination of ambulant casualties would be undertaken by the Fire and Rescue Service (FRS). The aim of this study was to track the movement of volunteer casualties at two mass decontamination field exercises using passive Radio Frequency Identification tags and detection mats that were placed at pre-defined locations. The exercise data were then used to inform a computer model of the FRS component of the mass decontamination process. Having removed all clothing and having showered, the re-dressing (termed re-robing) of casualties was found to be a bottleneck in the mass decontamination process during both exercises. Computer simulations showed that increasing the capacity of each lane of the re-robe section to accommodate 10 rather than five casualties would be optimal in general, but that a capacity of 15 might be required to accommodate vulnerable individuals. If the duration of the shower was decreased from three minutes to one minute then a per lane re-robe capacity of 20 might be necessary to maximise the throughput of casualties. In conclusion, one practical enhancement to the FRS response may be to provide at least one additional re-robe section per mass decontamination unit. PMID:23202768

  14. A measurement system applicable for landslide experiments in the field.

    PubMed

    Guo, Wen-Zhao; Xu, Xiang-Zhou; Wang, Wen-Long; Yang, Ji-Shan; Liu, Ya-Kun; Xu, Fei-Long

    2016-04-01

    Observation of gravity erosion in the field with strong sunshine and wind poses a challenge. Here, a novel topography meter together with a movable tent addresses the challenge. With the topography meter, a 3D geometric shape of the target surface can be digitally reconstructed. Before the commencement of a test, the laser generator position and the camera sightline should be adjusted with a sight calibrator. Typically, the topography meter can measure the gravity erosion on the slope with a gradient of 30°-70°. Two methods can be used to obtain a relatively clear video, despite the extreme steepness of the slopes. One method is to rotate the laser source away from the slope to ensure that the camera sightline remains perpendicular to the laser plane. Another way is to move the camera farther away from the slope in which the measured volume of the slope needs to be corrected; this method will reduce distortion of the image. In addition, installation of tent poles with concrete columns helps to surmount the altitude difference on steep slopes. Results observed by the topography meter in real landslide experiments are rational and reliable.

  15. A measurement system applicable for landslide experiments in the field

    NASA Astrophysics Data System (ADS)

    Guo, Wen-Zhao; Xu, Xiang-Zhou; Wang, Wen-Long; Yang, Ji-Shan; Liu, Ya-Kun; Xu, Fei-Long

    2016-04-01

    Observation of gravity erosion in the field with strong sunshine and wind poses a challenge. Here, a novel topography meter together with a movable tent addresses the challenge. With the topography meter, a 3D geometric shape of the target surface can be digitally reconstructed. Before the commencement of a test, the laser generator position and the camera sightline should be adjusted with a sight calibrator. Typically, the topography meter can measure the gravity erosion on the slope with a gradient of 30°-70°. Two methods can be used to obtain a relatively clear video, despite the extreme steepness of the slopes. One method is to rotate the laser source away from the slope to ensure that the camera sightline remains perpendicular to the laser plane. Another way is to move the camera farther away from the slope in which the measured volume of the slope needs to be corrected; this method will reduce distortion of the image. In addition, installation of tent poles with concrete columns helps to surmount the altitude difference on steep slopes. Results observed by the topography meter in real landslide experiments are rational and reliable.

  16. Modelling mass casualty decontamination systems informed by field exercise data.

    PubMed

    Egan, Joseph R; Amlôt, Richard

    2012-10-16

    In the event of a large-scale chemical release in the UK decontamination of ambulant casualties would be undertaken by the Fire and Rescue Service (FRS). The aim of this study was to track the movement of volunteer casualties at two mass decontamination field exercises using passive Radio Frequency Identification tags and detection mats that were placed at pre-defined locations. The exercise data were then used to inform a computer model of the FRS component of the mass decontamination process. Having removed all clothing and having showered, the re-dressing (termed re-robing) of casualties was found to be a bottleneck in the mass decontamination process during both exercises. Computer simulations showed that increasing the capacity of each lane of the re-robe section to accommodate 10 rather than five casualties would be optimal in general, but that a capacity of 15 might be required to accommodate vulnerable individuals. If the duration of the shower was decreased from three minutes to one minute then a per lane re-robe capacity of 20 might be necessary to maximise the throughput of casualties. In conclusion, one practical enhancement to the FRS response may be to provide at least one additional re-robe section per mass decontamination unit.

  17. Optically Programmable Field Programmable Gate Arrays (FPGA) Systems

    DTIC Science & Technology

    2004-01-01

    objective to image it onto a CCD camera with 9 µm pixel pitch. However, the system could have been made totally lensless by matching the pixels in the...be made as little as 1 cm. The module is very compact due to the lensless readout and to the small size of the area of the recording medium used to...architecture and lensless readout making the OPGA module very simple and compact. Once the recording operation is finished, the VCSEL array is assembled

  18. Extended depth-of-field iris recognition system for a workstation environment

    NASA Astrophysics Data System (ADS)

    Narayanswamy, Ramkumar; Silveira, Paulo E. X.; Setty, Harsha; Pauca, V. P.; van der Gracht, Joseph

    2005-03-01

    Iris recognition imaging is attracting considerable interest as a viable alternative for personal identification and verification in many defense and security applications. However current iris recognition systems suffer from limited depth of field, which makes usage of these systems more difficult by an untrained user. Traditionally, the depth of field is increased by reducing the imaging system aperture, which adversely impacts the light capturing power and thus the system signal-to-noise ratio (SNR). In this paper we discuss a computational imaging system, referred to as Wavefront Coded(R) imaging, for increasing the depth of field without sacrificing the SNR or the resolution of the imaging system. This system employs a especially designed Wavefront Coded lens customized for iris recognition. We present experimental results that show the benefits of this technology for biometric identification.

  19. Entanglement detection in a coupled atom-field system via quantum Fisher information

    NASA Astrophysics Data System (ADS)

    Mirkhalaf, Safoura Sadat; Smerzi, Augusto

    2017-02-01

    We consider a system of finite number of particles collectively interacting with a single-mode coherent field inside a cavity. Depending on the strength of the initial field compared to the number of atoms, we consider three regimes of weak-, intermediate-, and strong-field interaction. The dynamics of multiparticle entanglement detected by quantum Fisher information and spin squeezing are studied in each regime. It is seen that in the weak-field regime, spin squeezing and quantum Fisher information coincide. However, by increasing the initial field population toward the strong-field regime, quantum Fisher information is more effective in detecting entanglement compared to spin squeezing. In addition, in the two-atom system, we also study concurrence. In this case, the quantum Fisher information as a function of time is in good agreement with concurrence in predicting entanglement peaks.

  20. Dynamics of two-dimensional one-component and binary Yukawa systems in a magnetic field.

    PubMed

    Ott, T; Löwen, H; Bonitz, M

    2014-01-01

    We consider two-dimensional Yukawa systems in a perpendicular magnetic field. Computer simulations of both one-component and binary systems are used to explore the equilibrium particle dynamics in the fluid state. The mobility is found to scale with the inverse of the magnetic field strength (Bohm diffusion), for strong fields (ωc/ωp≳1). For bidisperse mixtures, the magnetic field dependence of the long-time mobility depends on the particle species, providing an external control of their mobility ratio. At large magnetic fields, the highly charged particles are almost immobilized by the magnetic field and form a porous matrix of obstacles for the mobile low-charge particles.

  1. Influence of external magnetic field on dynamics of open quantum systems.

    PubMed

    Kalandarov, Sh A; Kanokov, Z; Adamian, G G; Antonenko, N V

    2007-03-01

    The influence of an external magnetic field on the non-Markovian dynamics of an open two-dimensional quantum system is investigated. The fluctuations of collective coordinate and momentum and transport coefficients are studied for a charged harmonic oscillator linearly coupled to a neutral bosonic heat bath. It is shown that the dissipation of collective energy slows down with increasing strength of the external magnetic field. The role of magnetic field in the diffusion processes is illustrated by several examples.

  2. Three-Dimensional Steerable Magnetic Field (3DSMF) Sensor System for Classification of Buried Metal Targets

    DTIC Science & Technology

    2006-07-01

    complex spatial magnetic field distributions With a conventional pulsed EMI metal detector , a current loop transmitter is placed in the vicinity of the...transmitter via a data acquisition and control system. The direction of the magnetic field and the field strength generated by a conventional loop EMI metal ... detector are a complex function of the distance of the antenna to the target. As the antenna is moved over the target, data are collected from

  3. Influence of external magnetic field on dynamics of open quantum systems

    SciTech Connect

    Kalandarov, Sh. A.; Kanokov, Z.; Adamian, G. G.; Antonenko, N. V.

    2007-03-15

    The influence of an external magnetic field on the non-Markovian dynamics of an open two-dimensional quantum system is investigated. The fluctuations of collective coordinate and momentum and transport coefficients are studied for a charged harmonic oscillator linearly coupled to a neutral bosonic heat bath. It is shown that the dissipation of collective energy slows down with increasing strength of the external magnetic field. The role of magnetic field in the diffusion processes is illustrated by several examples.

  4. Performance of a two mirror, four reflection, ring field imaging system

    SciTech Connect

    Sommargren, G.E.

    1995-01-25

    The surface figure of the individual mirrors of a two mirror, four reflection, ring field imaging system has been measured after each phase of the construction process: substrate fabrication, coating and potting. Contributions to the final system wavefront error and performance of the system in terms of the modulation transfer function and initial imaging tests are discussed.

  5. Novel Hall sensors developed for magnetic field imaging systems.

    SciTech Connect

    Cambel, V.; Karapetrov, G.; Novosad, V.; Bartolome, E.; Gregusova, D.; Fedor, J.; Kudela, R.; Soltys, J.; Materials Science Division; Slovak Academy of Sciences; Univ. Autonoma de Barcelona

    2007-09-01

    We report here on the fabrication and application of novel planar Hall sensors based on shallow InGaP/AlGaAs/GaAs heterostructure with a two-dimensional electron gas (2DEG) as an active layer. The sensors are developed for two kinds of experiments. In the first one, magnetic samples are placed directly on the Hall sensor. Room temperature experiments of permalloy objects evaporated onto the sensor are presented. In the second experiment, the sensor scans close over a multigranular superconducting sample prepared on a YBCO thin film. Large-area and high-resolution scanning experiments were performed at 4.2 K with the Hall probe scanning system in a liquid helium flow cryostat.

  6. Controllable optical output fields from an optomechanical system with mechanical driving

    NASA Astrophysics Data System (ADS)

    Xu, Xun-Wei; Li, Yong

    2015-08-01

    We investigate the properties of the optical output fields from a cavity optomechanical system, where the cavity is optically driven by a strong coupling field and a weak probe field and the mechanical resonator is driven by a coherent mechanical pump. When the frequency of the mechanical pump matches the frequency difference between the coupling and probe optical fields, due to the interference between the different optical components at the same frequency, we demonstrate that the large positive or negative group delay of the output field at the frequency of probe field can be achieved and tuned by adjusting the phase and amplitude of the mechanical driving field. Moreover, the strength of the output field at the frequency of an optical four-wave-mixing (FWM) field also can be controlled (enhanced and suppressed) by tuning the phase and amplitude of the mechanical pump. We show that the power of the output field at the frequency of the optical FWM field can be suppressed to zero or enhanced so much that it can be comparable with and even larger than the power of the input probe optical field.

  7. Magnetic fields greater than 10 to the 20th power gauss. [in astrophysical systems

    NASA Technical Reports Server (NTRS)

    Lerche, I.; Schramm, D. N.

    1977-01-01

    Zaumen (1976) found that spontaneous pair production in a uniform magnetic field should be a feasible process for field strengths at least of the order of 10 to the 20th power gauss. This note points out that a magnetic field of this order of magnitude is most unlikely to occur in realistic astrophysical situations because of the large dynamical and quantum-mechanical effects such a field would produce. It is suggested that Zaumen's calculation would probably have little bearing on the suspected evolution of astrophysical systems since other processes (either dynamical or quantum-mechanical) apparently limit the field strength before such high magnetic fields would be reached. An upper limit of about 10 to the 16th power gauss is obtained by considering the isotropy of the 3-K blackbody radiation, the formation of collapsed objects in very high magnetic fields, and magnetic bremsstrahlung processes in quantum electrodynamics.

  8. Human Exposure to Electromagnetic Fields from Parallel Wireless Power Transfer Systems

    PubMed Central

    Wen, Feng; Huang, Xueliang

    2017-01-01

    The scenario of multiple wireless power transfer (WPT) systems working closely, synchronously or asynchronously with phase difference often occurs in power supply for household appliances and electric vehicles in parking lots. Magnetic field leakage from the WPT systems is also varied due to unpredictable asynchronous working conditions. In this study, the magnetic field leakage from parallel WPT systems working with phase difference is predicted, and the induced electric field and specific absorption rate (SAR) in a human body standing in the vicinity are also evaluated. Computational results are compared with the restrictions prescribed in the regulations established to limit human exposure to time-varying electromagnetic fields (EMFs). The results show that the middle region between the two WPT coils is safer for the two WPT systems working in-phase, and the peripheral regions are safer around the WPT systems working anti-phase. Thin metallic plates larger than the WPT coils can shield the magnetic field leakage well, while smaller ones may worsen the situation. The orientation of the human body will influence the maximum magnitude of induced electric field and its distribution within the human body. The induced electric field centralizes in the trunk, groin, and genitals with only one exception: when the human body is standing right at the middle of the two WPT coils working in-phase, the induced electric field focuses on lower limbs. The SAR value in the lungs always seems to be greater than in other organs, while the value in the liver is minimal. Human exposure to EMFs meets the guidelines of the International Committee on Non-Ionizing Radiation Protection (ICNIRP), specifically reference levels with respect to magnetic field and basic restrictions on induced electric fields and SAR, as the charging power is lower than 3.1 kW and 55.5 kW, respectively. These results are positive with respect to the safe applications of parallel WPT systems working

  9. Human Exposure to Electromagnetic Fields from Parallel Wireless Power Transfer Systems.

    PubMed

    Wen, Feng; Huang, Xueliang

    2017-02-08

    The scenario of multiple wireless power transfer (WPT) systems working closely, synchronously or asynchronously with phase difference often occurs in power supply for household appliances and electric vehicles in parking lots. Magnetic field leakage from the WPT systems is also varied due to unpredictable asynchronous working conditions. In this study, the magnetic field leakage from parallel WPT systems working with phase difference is predicted, and the induced electric field and specific absorption rate (SAR) in a human body standing in the vicinity are also evaluated. Computational results are compared with the restrictions prescribed in the regulations established to limit human exposure to time-varying electromagnetic fields (EMFs). The results show that the middle region between the two WPT coils is safer for the two WPT systems working in-phase, and the peripheral regions are safer around the WPT systems working anti-phase. Thin metallic plates larger than the WPT coils can shield the magnetic field leakage well, while smaller ones may worsen the situation. The orientation of the human body will influence the maximum magnitude of induced electric field and its distribution within the human body. The induced electric field centralizes in the trunk, groin, and genitals with only one exception: when the human body is standing right at the middle of the two WPT coils working in-phase, the induced electric field focuses on lower limbs. The SAR value in the lungs always seems to be greater than in other organs, while the value in the liver is minimal. Human exposure to EMFs meets the guidelines of the International Committee on Non-Ionizing Radiation Protection (ICNIRP), specifically reference levels with respect to magnetic field and basic restrictions on induced electric fields and SAR, as the charging power is lower than 3.1 kW and 55.5 kW, respectively. These results are positive with respect to the safe applications of parallel WPT systems working

  10. Error Field Correction in ITER

    SciTech Connect

    Park, Jong-kyu; Boozer, Allen H.; Menard, Jonathan E.; Schaffer, Michael J.

    2008-05-22

    A new method for correcting magnetic field errors in the ITER tokamak is developed using the Ideal Perturbed Equilibrium Code (IPEC). The dominant external magnetic field for driving islands is shown to be localized to the outboard midplane for three ITER equilibria that represent the projected range of operational scenarios. The coupling matrices between the poloidal harmonics of the external magnetic perturbations and the resonant fields on the rational surfaces that drive islands are combined for different equilibria and used to determine an ordered list of the dominant errors in the external magnetic field. It is found that efficient and robust error field correction is possible with a fixed setting of the correction currents relative to the currents in the main coils across the range of ITER operating scenarios that was considered.

  11. Playing the (Sexual) Field: The Interactional Basis of Systems of Sexual Stratification

    ERIC Educational Resources Information Center

    Green, Adam Isaiah

    2011-01-01

    Recently, scholars have used a Bourdieusian theory of practice to analyze systems of sexual stratification, including an examination of sexual fields and sexual (or erotic) capital. While the broad structural features of the sexual field have been a point of focus in this latter research, a systematic analysis of the interactional processes that…

  12. International Relations as a Field of Study in the Canadian System of Higher Education

    ERIC Educational Resources Information Center

    Istomina, Kateryna

    2015-01-01

    The research presents an attempt to investigate the current state of international relations as a field of study in the context of higher education system in Canada. It contains a general overview of the field of study, focusing predominantly on the role and function of the given academic discipline. The scientific investigation covers the issue…

  13. Electric Field-Mediated Processing of Biomaterials: Toward Nanostructured Biomimetic Systems. Appendix 3

    NASA Technical Reports Server (NTRS)

    Bowlin, Gary L.; Simpson, David G.; Lam, Philippe; Wnek, Gary E.

    2001-01-01

    Significant opportunities exist for the processing of synthetic and biological polymers using electric fields ('electroprocessing'). We review casting of multi-component films and the spinning of fibers in electric fields, and indicate opportunities for the creation of smart polymer systems using these approaches. Applications include 2-D substrates for cell growth and diagnostics, scaffolds for tissue engineering and repair, and electromechanically active biosystems.

  14. Fibre Fabry - Perot cavity-based aperture probe for near-field optical microscopy systems

    SciTech Connect

    Kulchin, Yurii N; Vitrik, O B; Bezverbnyi, A V; Pustovalov, E V; Kuchmizhak, A A; Nepomnyashchii, A V

    2011-03-31

    We report a theoretical analysis and experimental study of the possibility of producing a novel type of interferometric near-field aperture probe for near-field optical microscopy systems using a fibre Fabry - Perot microcavity with a nanometre-scale aperture made in one of its output mirrors. The probe ensures a spatial resolution no worse than {lambda}/14. (fibre optics)

  15. Spatiotemporal chaos in sine-Gordon systems subjected to wave fields: onset and suppression.

    PubMed

    Chacón, R; Bellorín, A; Guerrero, L E; González, J A

    2008-04-01

    The onset of spatiotemporal chaos in a damped sine-Gordon system subjected to a plane wave field as well as its suppression by an additional small-amplitude plane wave field are proposed theoretically and confirmed numerically. The relevance of these findings in the context of nonlinear magnetization waves is discussed.

  16. 21 CFR 892.1715 - Full-field digital mammography system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Full-field digital mammography system. 892.1715 Section 892.1715 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1715 Full-field digital...

  17. 21 CFR 892.1715 - Full-field digital mammography system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Full-field digital mammography system. 892.1715 Section 892.1715 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1715 Full-field digital...

  18. 21 CFR 892.1715 - Full-field digital mammography system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Full-field digital mammography system. 892.1715 Section 892.1715 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1715 Full-field digital...

  19. 21 CFR 892.1715 - Full-field digital mammography system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Full-field digital mammography system. 892.1715 Section 892.1715 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1715 Full-field digital...

  20. Method and systems for collecting data from multiple fields of view

    NASA Technical Reports Server (NTRS)

    Schwemmer, Geary K. (Inventor)

    2002-01-01

    Systems and methods for processing light from multiple fields (48, 54, 55) of view without excessive machinery for scanning optical elements. In an exemplary embodiment of the invention, multiple holographic optical elements (41, 42, 43, 44, 45), integrated on a common film (4), diffract and project light from respective fields of view.