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Sample records for solenoidal magnetic field

  1. MICE Spectrometer Solenoid Magnetic Field Measurements

    SciTech Connect

    Leonova, M.

    2013-09-01

    The Muon Ionization Cooling Experiment (MICE) is designed to demonstrate ionization cooling in a muon beam. Its goal is to measure a 10% change in transverse emittance of a muon beam going through a prototype Neutrino Factory cooling channel section with an absolute measurement accuracy of 0.1%. To measure emittances, MICE uses two solenoidal spectrometers, with Solenoid magnets designed to have 4 T fields, uniform at 3 per mil level in the tracking volumes. Magnetic field measurements of the Spectrometer Solenoid magnet SS2, and analysis of coil parameters for input into magnet models will be discussed.

  2. 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.

  3. Error field generation of solenoid magnets

    SciTech Connect

    Saunders, J.L.

    1982-01-01

    Many applications for large solenoids and solenoidal arrays depend on the high precision of the axial field profile. In cases where requirements of ..delta..B/B for nonaxial fields are on the order of 10/sup -4/, the actual winding techniques of the solenoid need to be considered. Whereas an ideal solenoid consisting of current loops would generate no radial fields along the axis, in reality, the actual current-carrying conductors must follow spiral or helical paths. A straightforward method for determining the radial error fields generated by coils wound with actual techniques employed in magnet fabrication has been developed. The method devised uses a computer code which models a magnet by sending a single, current-carrying filament along the same path taken by the conductor during coil winding. Helical and spiral paths are simulated using small, straight-line current segments. This technique, whose results are presented in this paper, was used to predict radial field errors for the Elmo Bumpy Torus-Proof of Principle magnet. These results include effects due to various winding methods, not only spiral/helical and layer-to-layer transitions, but also the effects caused by worst-case tolerance conditions both from the conductor and the winding form (bobbin). Contributions made by extraneous circuitry (e.g., overhead buswork and incoming leads) are also mentioned.

  4. An elementary argument for the magnetic field outside a solenoid

    NASA Astrophysics Data System (ADS)

    Pathak, Aritro

    2017-01-01

    The evaluation of the magnetic field inside and outside a uniform current density infinite solenoid of uniform cross-section is an elementary problem in classical electrodynamics that all undergraduate Physics students study. Symmetry properties of the cylinder and the judicious use of Ampere’s circuital law leads to correct results; however it does not explain why the field is non zero for a finite length solenoid, and why it vanishes as the solenoid becomes infinitely long. An argument is provided in Farley and Price (2001 Am. J. Phys. 69 751), explaining how the magnetic field behaves outside the solenoid and not too far from it, as a function of the length of the solenoid. A calculation is also outlined for obtaining the field just outside the circular cross section solenoid, in the classic text Classical Electrodynamics by Jackson, 3rd edn (John Wiley and Sons, Inc.), problems 5.3-5.5. The purpose of this paper is to provide an elementary argument for why the field becomes negligible as the length of the solenoid is increased. A quantitative analysis is provided for the field outside the solenoid, at radial distances large compared to the linear dimension of the solenoid cross section.

  5. Effect of solenoidal magnetic field on drifting laser plasma

    NASA Astrophysics Data System (ADS)

    Takahashi, Kazumasa; Okamura, Masahiro; Sekine, Megumi; Cushing, Eric; Jandovitz, Peter

    2013-04-01

    An ion source for accelerators requires to provide a stable waveform with a certain pulse length appropriate to the application. The pulse length of laser ion source is easy to control because it is expected to be proportional to plasma drifting distance. However, current density decay is proportional to the cube of the drifting distance, so large current loss will occur under unconfined drift. We investigated the stability and current decay of a Nd:YAG laser generated copper plasma confined by a solenoidal field using a Faraday cup to measure the current waveform. It was found that the plasma was unstable at certain magnetic field strengths, so a baffle was introduced to limit the plasma diameter at injection and improve the stability. Magnetic field, solenoid length, and plasma diameter were varied in order to find the conditions that minimize current decay and maximize stability.

  6. Integration of RFQ beam coolers and solenoidal magnetic fields

    SciTech Connect

    Cavenago, M. Maggiore, M.; Porcellato, A. M.; Chiurlotto, F.; Comunian, M.; Galatà, A.; Romé, M.; Maero, G.; Cavaliere, F.

    2016-02-15

    Electromagnetic traps are a flexible and powerful method of controlling particle beams, possibly of exotic nuclei, with cooling (of energy spread and transverse oscillations) provided by collisions with light gases as in the Radio Frequency Quadrupole Cooler (RFQC). A RFQC prototype can be placed inside the existing Eltrap solenoid, capable of providing a magnetic flux density component B{sub z} up to 0.2 T, where z is the solenoid axis. Confinement in the transverse plane is provided both by B{sub z} and the rf voltage V{sub rf} (up to 1 kV at few MHz). Transport is provided by a static electric field E{sub z} (order of 100 V/m), while gas collisions (say He at 1 Pa, to be maintained by differential pumping) provide cooling or heating depending on V{sub rf}. The beamline design and the major parameters V{sub rf}, B{sub z} (which affect the beam transmission optimization) are here reported, with a brief description of the experimental setup.

  7. High-field magnetic resonance imaging using solenoid radiofrequency coils.

    PubMed

    Vegh, Viktor; Gläser, Philipp; Maillet, Donald; Cowin, Gary J; Reutens, David C

    2012-10-01

    High-resolution magnetic resonance imaging using dedicated high-field radiofrequency micro-coils at 16.4 T (700 MHz) was investigated. Specific solenoid coils primarily using silver and copper as conductors with enamel and polyurethane coatings were built to establish which coil configuration produces the best image. Image quality was quantified using signal-to-noise ratio and signal variation over regions of interest. Benchmarking was conducted using 5-mm diameter coils, as this size is comparable to an established coil of the same size. Our 1.4-mm-diameter coils were compared directly to each other, from which we deduce performance as a function of conductor material and coating. A variety of materials and conductor coatings allowed us to choose an optimal design, which we used to image a kidney section at 10-micron resolution. We applied zero-fill extrapolation to achieve 5-micron resolution.

  8. Using Experiment and Computer Modeling to Determine the Off-Axis Magnetic Field of a Solenoid

    ERIC Educational Resources Information Center

    Lietor-Santos, Juan Jose

    2014-01-01

    The study of the ideal solenoid is a common topic among introductory-based physics textbooks and a typical current arrangement in laboratory hands-on experiences where the magnetic field inside a solenoid is determined at different currents and at different distances from its center using a magnetic probe. It additionally provides a very simple…

  9. Development and Characterization of a High Magnetic Field Solenoid for Laser Plasma Experiments

    SciTech Connect

    Pollock, B B; Froula, D H; Davis, P F; Ross, J S; Divol, L; Fulkerson, S; Satariano, J; Price, D; Bower, J; Edwards, J; Town, R; Glenzer, S H; Offenberger, A A; Tynan, G R; James, A N

    2006-05-05

    An electromagnetic solenoid was developed to study the quenching of nonlocal heat transport in laser-produced gas-jet plasmas by high external magnetic fields. The solenoid, which is driven by a pulsed power system supplying 30 kJ, achieves fields exceeding 10 T. Temporally resolved measurements of the electron temperature profile transverse to a high power laser beam were obtained using Thomson Scattering. A method for optimizing the solenoid design based on the available stored energy is presented.

  10. A model of field and spherical aberration in soft/hard edge solenoid magnets.

    PubMed

    Biswas, B

    2013-10-01

    A solenoid magnetic field model is presented that describes the on axis field by a parameter of its hard edginess and axial half-width at half-maximum field, which universally define its spherical aberration without solving the ray equation. The model shows an increase in spherical aberration from real soft edge fields to hard edge models, as used in beam tracking. It compares well with existing field models. It simply and accurately finds the spherical aberration in many types of solenoids.

  11. Behavior of moving plasma in solenoidal magnetic field in a laser ion source.

    PubMed

    Ikeda, S; Takahashi, K; Okamura, M; Horioka, K

    2016-02-01

    In a laser ion source, a solenoidal magnetic field is useful to guide the plasma and to control the extracted beam current. However, the behavior of the plasma drifting in the magnetic field has not been well understood. Therefore, to investigate the behavior, we measured the plasma ion current and the total charge within a single pulse in the solenoid by changing the distance from the entrance of the solenoid to a detector. We observed that the decrease of the total charge along the distance became smaller as the magnetic field became larger and then the charge became almost constant with a certain magnetic flux density. The results indicate that the transverse spreading speed of the plasma decreased with increasing the field and the plasma was confined transversely with the magnetic flux density. We found that the reason of the confinement was not magnetization of ions but an influence induced by electrons.

  12. Behavior of moving plasma in solenoidal magnetic field in a laser ion source

    NASA Astrophysics Data System (ADS)

    Ikeda, S.; Takahashi, K.; Okamura, M.; Horioka, K.

    2016-02-01

    In a laser ion source, a solenoidal magnetic field is useful to guide the plasma and to control the extracted beam current. However, the behavior of the plasma drifting in the magnetic field has not been well understood. Therefore, to investigate the behavior, we measured the plasma ion current and the total charge within a single pulse in the solenoid by changing the distance from the entrance of the solenoid to a detector. We observed that the decrease of the total charge along the distance became smaller as the magnetic field became larger and then the charge became almost constant with a certain magnetic flux density. The results indicate that the transverse spreading speed of the plasma decreased with increasing the field and the plasma was confined transversely with the magnetic flux density. We found that the reason of the confinement was not magnetization of ions but an influence induced by electrons.

  13. Behavior of moving plasma in solenoidal magnetic field in a laser ion source

    SciTech Connect

    Ikeda, S.; Takahashi, K.; Okamura, M.; Horioka, K.

    2016-02-15

    In a laser ion source, a solenoidal magnetic field is useful to guide the plasma and to control the extracted beam current. However, the behavior of the plasma drifting in the magnetic field has not been well understood. Therefore, to investigate the behavior, we measured the plasma ion current and the total charge within a single pulse in the solenoid by changing the distance from the entrance of the solenoid to a detector. We observed that the decrease of the total charge along the distance became smaller as the magnetic field became larger and then the charge became almost constant with a certain magnetic flux density. The results indicate that the transverse spreading speed of the plasma decreased with increasing the field and the plasma was confined transversely with the magnetic flux density. We found that the reason of the confinement was not magnetization of ions but an influence induced by electrons.

  14. A New Facility for Testing Superconducting Solenoid Magnets with Large Fringe Fields at Fermilab

    SciTech Connect

    Orris, D.; Carcagno, R.; Nogiec, J.; Rabehl, R.; Sylvester, C.; Tartaglia, M.

    2013-09-01

    Testing superconducting solenoid with no iron flux return can be problematic for a magnet test facility due to the large magnetic fringe fields generated. These large external fields can interfere with the operation of equipment while precautions must be taken for personnel supporting the test. The magnetic forces between the solenoid under test and the external infrastructure must also be taken under consideration. A new test facility has been designed and built at Fermilab specifically for testing superconducting magnets with large external fringe fields. This paper discusses the test stand design, capabilities, and details of the instrumentation and controls with data from the first solenoid tested in this facility: the Muon Ionization Cooling Experiment (MICE) coupling coil.

  15. GigaGauss solenoidal magnetic field inside bubbles excited in under-dense plasma

    NASA Astrophysics Data System (ADS)

    Lécz, Zs.; Konoplev, I. V.; Seryi, A.; Andreev, A.

    2016-10-01

    This paper proposes a novel and effective method for generating GigaGauss level, solenoidal quasi-static magnetic fields in under-dense plasma using screw-shaped high intensity laser pulses. This method produces large solenoidal fields that move with the driving laser pulse and are collinear with the accelerated electrons. This is in contrast with already known techniques which rely on interactions with over-dense or solid targets and generates radial or toroidal magnetic field localized at the stationary target. The solenoidal field is quasi-stationary in the reference frame of the laser pulse and can be used for guiding electron beams. It can also provide synchrotron radiation beam emittance cooling for laser-plasma accelerated electron and positron beams, opening up novel opportunities for designs of the light sources, free electron lasers, and high energy colliders based on laser plasma acceleration.

  16. GigaGauss solenoidal magnetic field inside bubbles excited in under-dense plasma

    PubMed Central

    Lécz, Zs.; Konoplev, I. V.; Seryi, A.; Andreev, A.

    2016-01-01

    This paper proposes a novel and effective method for generating GigaGauss level, solenoidal quasi-static magnetic fields in under-dense plasma using screw-shaped high intensity laser pulses. This method produces large solenoidal fields that move with the driving laser pulse and are collinear with the accelerated electrons. This is in contrast with already known techniques which rely on interactions with over-dense or solid targets and generates radial or toroidal magnetic field localized at the stationary target. The solenoidal field is quasi-stationary in the reference frame of the laser pulse and can be used for guiding electron beams. It can also provide synchrotron radiation beam emittance cooling for laser-plasma accelerated electron and positron beams, opening up novel opportunities for designs of the light sources, free electron lasers, and high energy colliders based on laser plasma acceleration. PMID:27796327

  17. A HIGH FIELD PULSED SOLENOID MAGNET FOR LIQUID METAL TARGET STUDIES.

    SciTech Connect

    KIRK,H.G.IAROCCI,M.SCADUTO,J.WEGGEL,R.J.MULHOLLAND,G.MCDONALD,K.T.

    2003-05-12

    The target system for a muon collider/neutrino factory requires the conjunction of an intense proton beam, a high-Z liquid target and a high-field solenoid magnet. We describe here the design parameters for a pulsed solenoid, including the magnet cryogenic system and power supply, that can generate transient fields of greater than 10T with a flat-tops on the order of 1 second. It is envisioned to locate this device at the Brookhaven AGS for proof-of-principle testing of a liquid-jet target system with pulses of le13 protons.

  18. Magnetic Field, Force, and Inductance Computations for an Axially Symmetric Solenoid

    NASA Technical Reports Server (NTRS)

    Lane, John E.; Youngquist, Robert C.; Immer, Christopher D.; Simpson, James C.

    2001-01-01

    The pumping of liquid oxygen (LOX) by magnetic fields (B field), using an array of electromagnets, is a current topic of research and development at Kennedy Space Center, FL. Oxygen is paramagnetic so that LOX, like a ferrofluid, can be forced in the direction of a B field gradient. It is well known that liquid oxygen has a sufficient magnetic susceptibility that a strong magnetic gradient can lift it in the earth's gravitational field. It has been proposed that this phenomenon can be utilized in transporting (i.e., pumping) LOX not only on earth, but on Mars and in the weightlessness of space. In order to design and evaluate such a magnetic pumping system, it is essential to compute the magnetic and force fields, as well as inductance, of various types of electromagnets (solenoids). In this application, it is assumed that the solenoids are air wrapped, and that the current is essentially time independent.

  19. The Magnetic Field inside a Long Solenoid--A New Approach

    ERIC Educational Resources Information Center

    Andrews, David; Carlton, Kevin; Lisgarten, David

    2010-01-01

    This article describes a technique for measuring the magnetic field inside a long solenoid using computer data logging. This is a new approach to a standard student practical. The design and construction of the sensors is described; they significantly reduce the cost of the apparatus. The approach of the practical is for the students to…

  20. Magnetic latching solenoid

    DOEpatents

    Marts, D.J.; Richardson, J.G.; Albano, R.K.; Morrison, J.L. Jr.

    1995-11-28

    This invention discloses a D.C. magnetic latching solenoid that retains a moving armature in a first or second position by means of a pair of magnets, thereby having a zero-power requirement after actuation. The first or second position is selected by reversing the polarity of the D.C. voltage which is enough to overcome the holding power of either magnet and transfer the armature to an opposite position. The coil is then de-energized. 2 figs.

  1. Magnetic latching solenoid

    DOEpatents

    Marts, Donna J.; Richardson, John G.; Albano, Richard K.; Morrison, Jr., John L.

    1995-01-01

    This invention discloses a D.C. magnetic latching solenoid that retains a moving armature in a first or second position by means of a pair of magnets, thereby having a zero-power requirement after actuation. The first or second position is selected by reversing the polarity of the D.C. voltage which is enough to overcome the holding power of either magnet and transfer the armature to an opposite position. The coil is then de-energized.

  2. Collective instabilities of the electron beam in magnetic fields of a helical undulator and solenoid

    NASA Astrophysics Data System (ADS)

    Artamonov, A. S.; Inozemtsev, N. I.

    1989-03-01

    The collective instabilities of a continuous electron beam propagating in the magnetic fields of a helical undulator and solenoid are analyzed theoretically in the framework of a one-dimensional model. Modulation of charge density is investigated along with modulation of the transverse velocity of the electrons by an electromagnetic wave. A dispersion equation describing the collective-excitation spectrum is obtained, and analyzed in the hydrodynamic approximation for two-, three-, and four-wave interaction.

  3. Solenoidal Magnet Installation

    SciTech Connect

    Stredde, H.; Lee, A.; /Fermilab

    1998-01-21

    The major modification to the D0 detector for the next physics collider run is the upgrade of the central tracking system. The first component to be installed will be the solenoid magnet, with the central pre-shower attached. This engineering note is directed to the installation of the solenoid magnet and the equipment needed to accomplish this task. As part of the installation process, the main detector must undergo a change in position of one of its major components, namely the South End Calorimeter (SEC). This calorimeter must be completely decoupled from the main detector, i.e. all cabling and cryo lines removed. The equipment used for installing all calorimeters (bridge and support structures) will be put into position and the calorimeter (SEC) will be pulled off of the detector center beam and parked on the south sidewalk of the D0 Assembly Hall. The necessary cryo lines will re-connected in order to keep the cryostat cold. This calorimeter will remain here during the greater portion of the upgrade reconfiguration schedule. When this task is finished, the old central tracking system and its mounts will be removed from the bore of the Central Calorimeter (CC). The main detector is now ready to receive the new tracking system, starting with the solenoid magnet.

  4. The heat kernel for two Aharonov-Bohm solenoids in a uniform magnetic field

    NASA Astrophysics Data System (ADS)

    Šťovíček, Pavel

    2017-01-01

    A non-relativistic quantum model is considered with a point particle carrying a charge e and moving in the plane pierced by two infinitesimally thin Aharonov-Bohm solenoids and subjected to a perpendicular uniform magnetic field of magnitude B. Relying on a technique originally due to Schulman, Laidlaw and DeWitt which is applicable to Schrödinger operators on multiply connected configuration manifolds a formula is derived for the corresponding heat kernel. As an application of the heat kernel formula, approximate asymptotic expressions are derived for the lowest eigenvalue lying above the first Landau level and for the corresponding eigenfunction while assuming that | eB | R2 /(ħ c) is large, where R is the distance between the two solenoids.

  5. SolCalc: A Suite for the Calculation and the Display of Magnetic Fields Generated by Solenoid Systems

    SciTech Connect

    Lopes, M. L.

    2014-07-01

    SolCalc is a software suite that computes and displays magnetic fields generated by a three dimensional (3D) solenoid system. Examples of such systems are the Mu2e magnet system and Helical Solenoids for muon cooling systems. SolCalc was originally coded in Matlab, and later upgraded to a compiled version (called MEX) to improve solving speed. Matlab was chosen because its graphical capabilities represent an attractive feature over other computer languages. Solenoid geometries can be created using any text editor or spread sheets and can be displayed dynamically in 3D. Fields are computed from any given list of coordinates. The field distribution on the surfaces of the coils can be displayed as well. SolCalc was benchmarked against a well-known commercial software for speed and accuracy and the results compared favorably.

  6. Self-adjoint extensions of the Dirac Hamiltonian in the magnetic-solenoid field and related exact solutions

    SciTech Connect

    Gavrilov, S.P.; Gitman, D.M.; Smirnov, A.A.

    2003-02-01

    We study solutions of Dirac equation in the field of Aharonov-Bohm solenoid and a collinear uniform magnetic field. On this base we construct self-adjoint extensions of the Dirac Hamiltonian using von Neumann's theory of deficiency indices. We reduce (3+1)-dimensional problem to (2+1)-dimensional one by a proper choice of spin operator. Then we study the problem doing a finite radius regularization of the solenoid field. We exploit solutions of the latter problem to specify boundary conditions in the singular case.

  7. Perturbative Quantum Analysis and Classical Limit of the Electron Scattering by a Solenoidal Magnetic Field

    SciTech Connect

    Murguia, Gabriela; Moreno, Matias; Torres, Manuel

    2009-04-20

    A well known example in quantum electrodynamics (QED) shows that Coulomb scattering of unpolarized electrons, calculated to lowest order in perturbation theory, yields a results that exactly coincides (in the non-relativistic limit) with the Rutherford formula. We examine an analogous example, the classical and perturbative quantum scattering of an electron by a magnetic field confined in an infinite solenoid of finite radius. The results obtained for the classical and the quantum differential cross sections display marked differences. While this may not be a complete surprise, one should expect to recover the classical expression by applying the classical limit to the quantum result. This turn not to be the case. Surprisingly enough, it is shown that the classical result can not be recuperated even if higher order corrections are included. To recover the classic correspondence of the quantum scattering problem a suitable non-perturbative methodology should be applied.

  8. Charge and current neutralization of an ion-beam pulse propagating in a background plasma along a solenoidal magnetic field.

    PubMed

    Kaganovich, I D; Startsev, E A; Sefkow, A B; Davidson, R C

    2007-12-07

    The analytical studies show that the application of a small solenoidal magnetic field can drastically change the self-magnetic and self-electric fields of the beam pulse propagating in a background plasma. Theory predicts that when omega_{ce} approximately omega_{pe}beta_{b}, where omega_{ce} is the electron gyrofrequency, omega_{pe} is the electron plasma frequency, and beta_{b} is the ion-beam velocity relative to the speed of light, there is a sizable enhancement of the self-electric and self-magnetic fields due to the dynamo effect. Furthermore, the combined ion-beam-plasma system acts as a paramagnetic medium; i.e., the solenoidal magnetic field inside the beam pulse is enhanced.

  9. Controlling Charge and Current Neutralization of an Ion Beam Pulse in a Background Plasma by Application of a Solenoidal Magnetic Field I: Weak Magnetic Field Limit

    SciTech Connect

    Kaganovich, I. D., Startsev, E. A., Sefkow, A. B., Davidson, R. C.

    2008-10-10

    Propagation of an intense charged particle beam pulse through a background plasma is a common problem in astrophysics and plasma applications. The plasma can effectively neutralize the charge and current of the beam pulse, and thus provides a convenient medium for beam transport. The application of a small solenoidal magnetic field can drastically change the self-magnetic and self- electric fields of the beam pulse, thus allowing effective control of the beam transport through the background plasma. An analytic model is developed to describe the self-magnetic field of a finite- length ion beam pulse propagating in a cold background plasma in a solenoidal magnetic field. The analytic studies show that the solenoidal magnetic field starts to infuence the self-electric and self-magnetic fields when ωce > ωpeβb, where ωce = eβ/mec is the electron gyrofrequency, ωpe is the electron plasma frequency, and βb = Vb/c is the ion beam velocity relative to the speed of light. This condition typically holds for relatively small magnetic fields (about 100G). Analytical formulas are derived for the effective radial force acting on the beam ions, which can be used to minimize beam pinching. The results of analytic theory have been verified by comparison with the simulation results obtained from two particle-in-cell codes, which show good agreement.

  10. The superconducting solenoid magnets for MICE

    SciTech Connect

    Green, Michael A.

    2002-12-22

    The Muon Ionization Cooling Experiment (MICE) is a channel of superconducting solenoid magnets. The magnets in MICE are around the RF cavities, absorbers (liquid or solid) and the primary particle detectors [1], [2]. The MICE superconducting solenoid system consists of eighteen coils that are grouped in three types of magnet assemblies. The cooling channel consists of two complete cell of an SFOFO cooling channel. Each cell consists of a focusing coil pair around an absorber and a coupling coil around a RF cavity that re-accelerates the muons to their original momentum. At the ends of the experiment are uniform field solenoids for the particle detectors and a set of matching coils used to match the muon beam to the cooling cells. Three absorbers are used instead of two in order to shield the detectors from dark currents generated by the RF cavities at high operating acceleration gradients.

  11. Evolution of an electron energy distribution function in a weak dc magnetic field in solenoidal inductive plasma

    SciTech Connect

    Lee, Min-Hyong; Choi, Seong Wook

    2008-12-01

    We investigated the evolution of the electron energy distribution function (EEDF) in a solenoidal inductively coupled plasma surrounded by an axial dc magnetic field. The increase in the dc magnetic field caused the EEDF to evolve from a bi-Maxwellian to a Maxwellian distribution. At the discharge center, the number of low energy electrons was significantly reduced while the high energy electron population showed little change when a weak dc magnetic field was present. However, at the discharge radial boundary, the high energy electron population decreased significantly with the magnetic field while the change in low energy population was not prominent compared to the discharge boundary. These changes in EEDFs at the boundary and center of the discharge are due to the radial confinement and the restriction of radial transport of electrons by dc magnetic field.

  12. Bent Solenoids with Superimposed Dipole Fields

    SciTech Connect

    Meinke, Rainer, B.; Goodzeit, Carl, L.

    2000-03-21

    A conceptual design and manufacturing technique were developed for a superconducting bent solenoid magnet with a superimposed dipole field that would be used as a dispersion device in the cooling channel of a future Muon Collider. The considered bent solenoid is equivalent to a 180° section of a toroid with a major radius of ~610 mm and a coil aperture of ~416 mm. The required field components of this magnet are 4 tesla for the solenoid field and 1 tesla for the superimposed dipole field. A magnet of this size and shape, operating at these field levels, has to sustain large Lorentz forces resulting in a maximum magnetic pressure of about 2,000 psi. A flexible round mini-cable with 37 strands of Cu-NbTi was selected as the superconductor. Detailed magnetic analysis showed that it is possible to obtain the required superimposed dipole field by tilting the winding planes of the solenoid by ~25°. A complete structural analysis of the coil support system and the helium containment vessel under thermal, pressure, and Lorentz force loads was carried out using 3D finite element models of the structures. The main technical issues were studied and solutions were worked out so that a highly reliable magnet of this type can be produced at an affordable cost.

  13. Solenoid Magnet System for the Fermilab Mu2e Experiment

    SciTech Connect

    Lamm, M. J.; Andreev, N.; Ambrosio, G.; Brandt, J.; Coleman, R.; Evbota, D.; Kashikhin, V. V.; Lopes, M.; Miller, J.; Nicol, T.; Ostojic, R.; Page, T.; Peterson, T.; Popp, J.; Pronskikh, V.; Tang, Z.; Tartaglia, M.; Wake, M.; Wands, R.; Yamada, R.

    2011-12-14

    The Fermilab Mu2e experiment seeks to measure the rare process of direct muon to electron conversion in the field of a nucleus. Key to the design of the experiment is a system of three superconducting solenoids; a muon production solenoid (PS) which is a 1.8 m aperture axially graded solenoid with a peak field of 5 T used to focus secondary pions and muons from a production target located in the solenoid aperture; an 'S shaped' transport solenoid (TS) which selects and transports the subsequent muons towards a stopping target; a detector solenoid (DS) which is an axially graded solenoid at the upstream end to focus transported muons to a stopping target, and a spectrometer solenoid at the downstream end to accurately measure the momentum of the outgoing conversion elections. The magnetic field requirements, the significant magnetic coupling between the solenoids, the curved muon transport geometry and the large beam induced energy deposition into the superconducting coils pose significant challenges to the magnetic, mechanical, and thermal design of this system. In this paper a conceptual design for the magnetic system which meets the Mu2e experiment requirements is presented.

  14. Enhanced collective focusing of intense neutralized ion beam pulses in the presence of weak solenoidal magnetic fields

    DOE PAGES

    Dorf, Mikhail A.; Davidson, Ronald C.; Kaganovich, Igor D.; ...

    2012-05-31

    In this study, the design of ion drivers for warm dense matter and high energy density physics applications and heavy ion fusion involves transverse focusing and longitudinal compression of intense ion beams to a small spot size on the target. To facilitate the process, the compression occurs in a long drift section filled with a dense background plasma, which neutralizes the intense beam self-fields. Typically, the ion bunch charge is better neutralized than its current, and as a result a net self-pinching (magnetic) force is produced. The self-pinching effect is of particular practical importance, and is used in various ionmore » driver designs in order to control the transverse beam envelope. In the present work we demonstrate that this radial self-focusing force can be significantly enhanced if a weak (B~100 G) solenoidal magnetic field is applied inside the neutralized drift section, thus allowing for substantially improved transport. It is shown that in contrast to magnetic self-pinching, the enhanced collective self-focusing has a radial electric field component and occurs as a result of the overcompensation of the beam charge by plasmaelectrons, whereas the beam current becomes well-neutralized. As the beam leaves the neutralizing drift section, additional transverse focusing can be applied. For instance, in the neutralized drift compression experiments (NDCX) a strong (several Tesla) final focus solenoid is used for this purpose. In the present analysis we propose that the tight final focus in the NDCX experiments may possibly be achieved by using a much weaker (few hundred Gauss) magnetic lens, provided the ion beam carries an equal amount of co-moving neutralizing electrons from the preceding drift section into the lens. In this case the enhanced focusing is provided by the collective electrondynamics strongly affected by a weak applied magnetic field.« less

  15. Enhanced collective focusing of intense neutralized ion beam pulses in the presence of weak solenoidal magnetic fields

    SciTech Connect

    Dorf, Mikhail A.; Davidson, Ronald C.; Kaganovich, Igor D.; Startsev, Edward A.

    2012-05-31

    In this study, the design of ion drivers for warm dense matter and high energy density physics applications and heavy ion fusion involves transverse focusing and longitudinal compression of intense ion beams to a small spot size on the target. To facilitate the process, the compression occurs in a long drift section filled with a dense background plasma, which neutralizes the intense beam self-fields. Typically, the ion bunch charge is better neutralized than its current, and as a result a net self-pinching (magnetic) force is produced. The self-pinching effect is of particular practical importance, and is used in various ion driver designs in order to control the transverse beam envelope. In the present work we demonstrate that this radial self-focusing force can be significantly enhanced if a weak (B~100 G) solenoidal magnetic field is applied inside the neutralized drift section, thus allowing for substantially improved transport. It is shown that in contrast to magnetic self-pinching, the enhanced collective self-focusing has a radial electric field component and occurs as a result of the overcompensation of the beam charge by plasmaelectrons, whereas the beam current becomes well-neutralized. As the beam leaves the neutralizing drift section, additional transverse focusing can be applied. For instance, in the neutralized drift compression experiments (NDCX) a strong (several Tesla) final focus solenoid is used for this purpose. In the present analysis we propose that the tight final focus in the NDCX experiments may possibly be achieved by using a much weaker (few hundred Gauss) magnetic lens, provided the ion beam carries an equal amount of co-moving neutralizing electrons from the preceding drift section into the lens. In this case the enhanced focusing is provided by the collective electrondynamics strongly affected by a weak applied magnetic field.

  16. Measurements of the temporal onset of mega-Gauss magnetic fields in a laser-driven solenoid

    NASA Astrophysics Data System (ADS)

    Goyon, Clement; Polllock, B. B.; Turnbull, D. T.; Hazi, A.; Ross, J. S.; Mariscal, D. A.; Patankar, S.; Williams, G. J.; Farmer, W. A.; Moody, J. D.; Fujioka, S.; Law, K. F. F.

    2016-10-01

    We report on experimental results obtained at Omega EP showing a nearly linear increase of the B-field up to about 2 mega-Gauss in 0.75 ns in a 1 mm3 region. The field is generated using 1 TW of 351 nm laser power ( 8*1015 W/cm2) incident on a laser-driven solenoid target. The coil target converts about 1% of the laser energy into the B-field measured both inside and outside the coil using proton deflectometry with a grid and Faraday rotation of probe beam through SiO2 glass. Proton data indicates a current rise up to hundreds of kA with a spatial distribution in the Au solenoid conductor evolving in time. These results give insight into the generating mechanism of the current between the plates and the time behavior of the field. These experiments are motivated by recent efforts to understand and utilize High Energy Density (HED) plasmas in the presence of external magnetic fields in areas of research from Astrophysics to Inertial Confinement Fusion. We will describe the experimental results and scale them to a NIF hohlraum size. This work was performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344.

  17. Solenoid Magnet System for the Fermilab Mu2e Experiment

    DOE PAGES

    Lamm, M. J.; Andreev, N.; Ambrosio, G.; ...

    2011-12-14

    The Fermilab Mu2e experiment seeks to measure the rare process of direct muon to electron conversion in the field of a nucleus. Key to the design of the experiment is a system of three superconducting solenoids; a muon production solenoid (PS) which is a 1.8 m aperture axially graded solenoid with a peak field of 5 T used to focus secondary pions and muons from a production target located in the solenoid aperture; an 'S shaped' transport solenoid (TS) which selects and transports the subsequent muons towards a stopping target; a detector solenoid (DS) which is an axially graded solenoidmore » at the upstream end to focus transported muons to a stopping target, and a spectrometer solenoid at the downstream end to accurately measure the momentum of the outgoing conversion elections. The magnetic field requirements, the significant magnetic coupling between the solenoids, the curved muon transport geometry and the large beam induced energy deposition into the superconducting coils pose significant challenges to the magnetic, mechanical, and thermal design of this system. In this paper a conceptual design for the magnetic system which meets the Mu2e experiment requirements is presented.« less

  18. Analysis of off-axis solenoid fields using the magnetic scalar potential: An application to a Zeeman-slower for cold atoms

    NASA Astrophysics Data System (ADS)

    Muniz, Sérgio R.; Bagnato, Vanderlei S.; Bhattacharya, M.

    2015-06-01

    In a region free of currents, magnetostatics can be described by the Laplace equation of a scalar magnetic potential, and one can apply the same methods commonly used in electrostatics. Here, we show how to calculate the general vector field inside a real (finite) solenoid, using only the magnitude of the field along the symmetry axis. Our method does not require integration or knowledge of the current distribution and is presented through practical examples, including a nonuniform finite solenoid used to produce cold atomic beams via laser cooling. These examples allow educators to discuss the nontrivial calculation of fields off-axis using concepts familiar to most students, while offering the opportunity to introduce themes of current modern research.

  19. Miniature solenoid for the production of confined magnetic flux

    SciTech Connect

    Walker, I.R.

    1984-11-01

    For experiments involving SQUID's it is sometimes desirable to have a small source of confined magnetic field in order to provide a dc or RF flux bias. This has been done by closely winding number50 AWG copper wire on a 250-..mu..m-diam optical fiber. The resulting solenoid is very small and has excellent mechanical and electrical properties at 4 K.

  20. Experimental Results of a Single Emittance Compensation Solenoidal Magnet

    NASA Astrophysics Data System (ADS)

    Palmer, D. T.; Wang, X. J.; Ben-Zvi, I.; Miller, R. H.; Skaritka, J.

    1997-05-01

    A new iron dominated single emittance compensation solenoidal magnet was designed to be integrated with the BNL/SLAC/UCLA 1.6 cell S-Band Photocathode RF Gun. This emittance compensated photoinjector is now in operation at the Brookhaven Accelerator Test Facility. It has produced a 300 pC electron bunches with a normalized rms transverse emittance of ɛ_n,rms = 0.7 π mm mrad. POISSON field maps were used with PARMELA to optimize the emittance compensation solenoidal magnet design. Magnetic field measurements show that at the cathode plane Bz <= 10 gauss for a peak magnetic field of B_z,max = 3 KG. Which is in agreement with POISSON simulation. A single emittance compensation solenoidal magnet will produces a initial angular momentum of the electron bunch that manifests itself in a initial magnetic emittance term that cannot be eliminated. This magnetic emittance ɛ_mag,n,rms scales as 0.01 π mm mrad per gauss at the cathode. Which is in agreement with PARMELA simulations. Experimental beam dynamics results are presented that show spot size and emittance as a function of cathode magnetic field. These results are compared to theory and simulations.

  1. Whistler Wave Excitation and Effects of Self-Focusing on Ion Beam Propagation through a Background Plasma along a Solenoidal Magnetic Field

    SciTech Connect

    Mikhail, Dorf A.; Kaganovich, Igor D.; Startsev, Edward A.; Davidson, Ronald C.

    2010-02-02

    This paper extends studies of ion beam transport through a background plasma along a solenoidal magnetic field [I. Kaganovich et al., Phys. Plasmas 15, 103108 (2008)] to the important regime of moderate magnetic field strength satisfying ωce > 2βbωpe . Here, ωce and ω pe are the electron cyclotron frequency and electron plasma frequency, respectively, and βb = vb/ c is the directed ion beam velocity normalized to the speed of light. The electromagnetic field perturbations excited by the ion beam pulse in this regime are calculated analytically, and verified by comparison with the numerical simulations. The degrees of beam charge neutralization and current neutralization are estimated, and the transverse component of the Lorentz force associated with the excited electromagnetic field is calculated. It is found that the plasma response to the ion beam pulse is significantly different depending on whether the value of the solenoidal magnetic field is below or above the threshold value specified by ω cr ce = 2βbωpe, and corresponding to the resonant excitation of large-amplitude whistler waves. The use of intense whistler wave excitations for diagnostic purposes is also discussed.

  2. Magnetic Alignment of Pulsed Solenoids Using the Pulsed Wire Method

    SciTech Connect

    Arbelaez, D.; Madur, A.; Lipton, T.M.; Waldron, W.L.; Kwan, J.W.

    2011-04-01

    A unique application of the pulsed-wire measurement method has been implemented for alignment of 2.5 T pulsed solenoid magnets. The magnetic axis measurement has been shown to have a resolution of better than 25 {micro}m. The accuracy of the technique allows for the identification of inherent field errors due to, for example, the winding layer transitions and the current leads. The alignment system is developed for the induction accelerator NDCX-II under construction at LBNL, an upgraded Neutralized Drift Compression experiment for research on warm dense matter and heavy ion fusion. Precise alignment is essential for NDCX-II, since the ion beam has a large energy spread associated with the rapid pulse compression such that misalignments lead to corkscrew deformation of the beam and reduced intensity at focus. The ability to align the magnetic axis of the pulsed solenoids to within 100 pm of the induction cell axis has been demonstrated.

  3. Solenoid fringe field compensation for the Cluster Klystron

    SciTech Connect

    Wang, H.; Fernow, R.C.; Kirk, H.G.; Palmer, R.B.; Zhao, Y.

    1996-04-01

    Optimization of the solenoid pancake currents so as to have a uniform axial magnetic field over an extended volume, is very important for the successful operation of the Cluster Klystron. By boosting the first and the last pancake currents by 35%, a uniform field Br/Bz {le} 0.1% at radius R {le} 2 cm can be extended from {+-} 7 cm to {+-} 16 cm. The result confirms simulations and the requirements for a 3-beam Cluster Klystron Experiment are achieved.

  4. Laser ion source with solenoid field

    SciTech Connect

    Kanesue, Takeshi; Fuwa, Yasuhiro; Kondo, Kotaro; Okamura, Masahiro

    2014-11-12

    Pulse length extension of highly charged ion beam generated from a laser ion source is experimentally demonstrated. In this study, the laser ion source (LIS) has been recognized as one of the most powerful heavy ion source. However, it was difficult to provide long pulse beams. By applying a solenoid field (90 mT, 1 m) at plasma drifting section, a pulse length of carbon ion beam reached 3.2 μs which was 4.4 times longer than the width from a conventional LIS. The particle number of carbon ions accelerated by a radio frequency quadrupole linear accelerator was 1.2 × 1011, which was provided by a single 1 J Nd-YAG laser shot. A laser ion source with solenoid field could be used in a next generation heavy ion accelerator.

  5. Laser ion source with solenoid field

    DOE PAGES

    Kanesue, Takeshi; Fuwa, Yasuhiro; Kondo, Kotaro; ...

    2014-11-12

    Pulse length extension of highly charged ion beam generated from a laser ion source is experimentally demonstrated. In this study, the laser ion source (LIS) has been recognized as one of the most powerful heavy ion source. However, it was difficult to provide long pulse beams. By applying a solenoid field (90 mT, 1 m) at plasma drifting section, a pulse length of carbon ion beam reached 3.2 μs which was 4.4 times longer than the width from a conventional LIS. The particle number of carbon ions accelerated by a radio frequency quadrupole linear accelerator was 1.2 × 1011, whichmore » was provided by a single 1 J Nd-YAG laser shot. A laser ion source with solenoid field could be used in a next generation heavy ion accelerator.« less

  6. Laser ion source with solenoid field

    NASA Astrophysics Data System (ADS)

    Kanesue, Takeshi; Fuwa, Yasuhiro; Kondo, Kotaro; Okamura, Masahiro

    2014-11-01

    Pulse length extension of highly charged ion beam generated from a laser ion source is experimentally demonstrated. The laser ion source (LIS) has been recognized as one of the most powerful heavy ion source. However, it was difficult to provide long pulse beams. By applying a solenoid field (90 mT, 1 m) at plasma drifting section, a pulse length of carbon ion beam reached 3.2 μs which was 4.4 times longer than the width from a conventional LIS. The particle number of carbon ions accelerated by a radio frequency quadrupole linear accelerator was 1.2 × 1011, which was provided by a single 1 J Nd-YAG laser shot. A laser ion source with solenoid field could be used in a next generation heavy ion accelerator.

  7. The Mechanical Design Optimization of a High Field HTS Solenoid

    SciTech Connect

    Lalitha, SL; Gupta, RC

    2015-06-01

    This paper describes the conceptual design optimization of a large aperture, high field (24 T at 4 K) solenoid for a 1.7 MJ superconducting magnetic energy storage device. The magnet is designed to be built entirely of second generation (2G) high temperature superconductor tape with excellent electrical and mechanical properties at the cryogenic temperatures. The critical parameters that govern the magnet performance are examined in detail through a multiphysics approach using ANSYS software. The analysis results formed the basis for the performance specification as well as the construction of the magnet.

  8. Alternative Methods for Field Corrections in Helical Solenoids

    SciTech Connect

    Lopes, M. L.; Krave, S. T.; Tompkins, J. C.; Yonehara, K.; Flanagan, G.; Kahn, S. A.; Melconian, K.

    2015-05-01

    Helical cooling channels have been proposed for highly efficient 6D muon cooling. Helical solenoids produce solenoidal, helical dipole, and helical gradient field components. Previous studies explored the geometric tunability limits on these main field components. In this paper we present two alternative correction schemes, tilting the solenoids and the addition of helical lines, to reduce the required strength of the anti-solenoid and add an additional tuning knob.

  9. Effects of superposition of detector solenoid and FFS quadrupole fields in SLC and correction methods

    SciTech Connect

    Murray, J.J.

    1983-07-25

    For the so-called superconducting FFS option with L* = 2.2 m, the MK2 solenoid does not overlap Q1, the FFS quad nearest the IP. For the permanent magnet option with L* = 0.75 m, the MK2 solenoid would overlap both Q1 and Q2. In either case an 8 m long solenoid, contemplated for the SLD detector, would overlap both Q1 and Q2. The solenoid field cannot be shielded so in an overlap region one will have a superposition of solenoid an quadrupole fields. Recently, the question was raised, What are the optical consequences when the solenoid and quad fields are superimposed. The question had not been considered before, but rough estimates suggested immediately that there might indeed be ugly consequences in terms of an enlargement of spot size at the IP. The purpose of this note is to answer the question quantitatively and to consider methods of correction of the ugly consequences.

  10. Studies on the Magnetic Center of the Mu2e Solenoid System

    SciTech Connect

    Lopes, M. L.; Ambrosio, G.; Buehler, M.; Coleman, R.; Evbota, D.; Khalatian, V.; Lamm, M.; Miller, J.; Moretti, G.; Page, T.; Tartaglia, M.

    2014-01-01

    The definition of the magnetic center in the Mu2e solenoid system is not trivial given the S-shaped nature of the transport solenoid. Moreover, due to the fringe field of the larger bore adjacent magnets-production solenoid and the detector solenoid-the magnetic center does not coincide with the geometric center of the system. The reference magnetic center can be obtained by tracking a low-momentum charged particle through the whole system. This paper will discuss this method and will evaluate the deviations from the nominal magnetic center given the tolerances in the manufacturing and the alignment of the coils. Methods for the correction of the magnetic center will also be presented.

  11. Processing and characterization of superconducting solenoids made of Bi-2212/Ag-alloy multifilament round wire for high field magnet applications

    NASA Astrophysics Data System (ADS)

    Chen, Peng

    As the only high temperature superconductor with round wire (RW) geometry, Bi2Sr2CaCu2O8+x (Bi-2212) superconducting wire has the advantages of being multi-filamentary, macroscopically isotropic and twistable. With overpressure (OP) processing techniques recently developed by our group at the National High Magnetic Field Laboratory (NHMFL), the engineering current density (Je) of Bi-2212 RW can be dramatically increased. For example, Je of more than 600 A/mm 2 (4.2 K and 20 T) is achieved after 100 bar OP processing. With these intrinsically beneficial properties and recent processing progress, Bi-2212 RW has become very attractive for high field magnet applications, especially for nuclear magnetic resonance (NMR) magnets and accelerator magnets etc. This thesis summarizes my graduate study on Bi-2212 solenoids for high field and high homogeneity NMR magnet applications, which mainly includes performance study of Bi-2212 RW insulations, 1 bar and OP processing study of Bi-2212 solenoids, and development of superconducting joints between Bi-2212 RW conductors. Electrical insulation is one of the key components of Bi-2212 coils to provide sufficient electrical standoff within coil winding pack. A TiO 2/polymer insulation offered by nGimat LLC was systematically investigated by differential thermal analysis (DTA), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), dielectric property measurements, and transport critical current (Ic) property measurements. About 29% of the insulation by weight is polymer. When the Bi-2212 wire is fully heat treated, this decomposes with slow heating to 400 °C in flowing O2. After the full reaction, we found that the TiO2 did not degrade the critical current properties, adhered well to the conductor, and provided a breakdown voltage of more than 100 V. A Bi-2212 RW wound solenoid coil was built using this insulation being offered by nGimat LLC. The coil resistance was constant through coil winding, polymer burn

  12. Solenoidal Fields for Ion Beam Transport and Focusing

    SciTech Connect

    Lee, Edward P.; Leitner, Matthaeus

    2007-11-01

    In this report we calculate time-independent fields of solenoidal magnets that are suitable for ion beam transport and focusing. There are many excellent Electricity and Magnetism textbooks that present the formalism for magnetic field calculations and apply it to simple geometries [1-1], but they do not include enough relevant detail to be used for designing a charged particle transport system. This requires accurate estimates of fringe field aberrations, misaligned and tilted fields, peak fields in wire coils and iron, external fields, and more. Specialized books on magnet design, technology, and numerical computations [1-2] provide such information, and some of that is presented here. The AIP Conference Proceedings of the US Particle Accelerator Schools [1-3] contain extensive discussions of design and technology of magnets for ion beams - except for solenoids. This lack may be due to the fact that solenoids have been used primarily to transport and focus particles of relatively low momenta, e.g. electrons of less than 50 MeV and protons or H- of less than 1.0 MeV, although this situation may be changing with the commercial availability of superconducting solenoids with up to 20T bore field [1-4]. Internal reports from federal laboratories and industry treat solenoid design in detail for specific applications. The present report is intended to be a resource for the design of ion beam drivers for Inertial Fusion Energy [1-5] and Warm Dense Matter experiments [1-6], although it should also be useful for a broader range of applications. The field produced by specified currents and material magnetization can always be evaluated by solving Maxwell's equations numerically, but it is also desirable to have reasonably accurate, simple formulas for conceptual system design and fast-running beam dynamics codes, as well as for general understanding. Most of this report is devoted to such formulas, but an introduction to the Tosca{copyright} code [1-7] and some numerical

  13. Residual magnetism holds solenoid armature in desired position

    NASA Technical Reports Server (NTRS)

    Crawford, R. P.

    1967-01-01

    Holding solenoid uses residual magnetism to hold its armature in a desired position after excitation current is removed from the coil. Although no electrical power or mechanical devices are used, the solenoid has a low tolerance to armature displacement from the equilibrium position.

  14. Beam transport with magnetic solenoids and plasma lenses

    SciTech Connect

    Noble, R.J.

    1988-10-01

    We examine the behavior of axisymmetric space-charge dominated beams in transport lines using numerical simulation. A typical transport line consisting of two axisymmetric linear lenses used to make a continuous beam from an ion source to a radio frequency quadrupole (RFQ) is considered. We compare the beam evolution when both lenses are magnetic solenoids or Gabor plasma lenses for beams with different initial density profiles. Emittance oscillations due to nonlinear space-charge forces by the action of plasma lenses in which space-charge fields are shielded, but beam mismatch at the RFQ entrance can be significant for both types of lens. 8 refs., 6 figs.

  15. Optimum dimensions of power solenoids for magnetic suspension

    NASA Technical Reports Server (NTRS)

    Kaznacheyev, B. A.

    1985-01-01

    Design optimization of power solenoids for controllable and stabilizable magnetic suspensions with force compensation in a wind tunnel is shown. It is assumed that the model of a levitating body is a sphere of ferromagnetic material with constant magnetic permeability. This sphere, with a radius much smaller than its distance from the solenoid above, is to be maintained in position on the solenoid axis by balance of the vertical electromagnetic force and the force of gravitation. The necessary vertical (axial) force generated by the solenoid is expressed as a function of relevant system dimensions, solenoid design parameters, and physical properties of the body. Three families of curves are obtained which depict the solenoid power for a given force as a function of the solenoid length with either outside radius or inside radius as a variable parameter and as a function of the outside radius with inside radius as a variable parameter. The curves indicate the optimum solenoid length and outside radius, for minimum power, corresponding to a given outside radius and inside radius, respectively.

  16. Design and optimization of a HTS insert for solenoid magnets

    NASA Astrophysics Data System (ADS)

    Tomassetti, Giordano; de Marzi, Gianluca; Muzzi, Luigi; Celentano, Giuseppe; della Corte, Antonio

    2016-12-01

    With the availability of High-Temperature Superconducting (HTS) prototype cables, based on high-performance REBCO Coated Conductor (CC) tapes, new designs can now be made for large bore high-field inserts in superconducting solenoids, thus extending the magnet operating point to higher magnetic fields. In this work, as an alternative approach to the standard trial-and-error design process, an optimization procedure for a HTS grading section design is proposed, including parametric electro-magnetic and structural analyses, using the ANSYS software coupled with a numerically-efficient optimization algorithm. This HTS grading section is designed to be inserted into a 12 T large bore Low-Temperature Superconducting (LTS) solenoid (diameter about 1 m) to increase the field up to a maximum value of at least 17 T. The optimization variables taken into consideration are the number of turns and layers and the circle-in-square jacket inner diameter in order to minimize the total needed conductor length to achieve a peak field of at least 17 T, while guaranteeing the structural integrity and manufacturing constraints. By means of the optimization, an optimal 360 m total conductor length was found, achieving 17.2 T with an operating current of 22.4 kA and a coil comprised of 18 × 12 turns, shortened of about 20% with respect to the best initial candidate architectural design. The optimal HTS insert has a bore compatible with manufacturing constraints (inner bore radius larger than 30 cm). A scaled HTS insert for validation purposes, with a reduced conductor length, to be tested in an advanced experimental facility currently under construction, is also mentioned.

  17. A cryogenic test stand for large superconducting solenoid magnets

    NASA Astrophysics Data System (ADS)

    Rabehl, R.; Carcagno, R.; Nogiec, J.; Orris, D.; Soyars, W.; Sylvester, C.

    2014-01-01

    A new test stand for testing large superconducting solenoid magnets at the Fermilab Central Helium Liquefier (CHL) has been designed, installed, and operated. This test stand is being used to test a coupling coil for the Muon Ionization Cooling Experiment (MICE), and future uses include solenoids for the Fermilab μ2e experiment. This paper describes the test stand design and operation including controlled cool-down and warm-up. Overviews of the process controls system and the quench management system are also included.

  18. A Cryogenic Test Stand for Large Superconducting Solenoid Magnets

    SciTech Connect

    Rabehl, R.; Carcagno, R.; Nogiec, J.; Orris, D.; Soyars, W.; Sylvester, C.

    2013-01-01

    A new test stand for testing large superconducting solenoid magnets at the Fermilab Central Helium Liquifier (CHL) has been designed, and operated. This test stand has been used to test a coupling coil for the Muon Ionization Cooling Experiment (MICE), and future uses include solenoids for the Fermilab mu2e experiment. This paper describes the test stand design and operation including controlled cool-down and warm-up. Overviews of the process controls system and the quench management system are also included.

  19. Magnetic and Cryogenic Design of the MICE Coupling Solenoid Magnet System

    SciTech Connect

    Wang, Li; Xu, FengYu; Wu, Hong; Liu, XiaoKum; Li, LanKai; Guo, XingLong; Chen, AnBin; Green, Michael A; Li, D.R.; Virostek, Steve; Pan, H.

    2008-08-02

    The Muon Ionization Cooling Experiment (MICE) will demonstrate ionization cooling in a short section of a realistic cooling channel using a muon beam at Rutherford Appleton Laboratory in the UK. The coupling magnet is a superconducting solenoid mounted around four 201MHz RF cavities, which produces magnetic field up to 2.6 T on the magnet centerline to keep muons within the iris of RF cavities windows. The coupling coil with inner radius of 750mm, length of 285mm and thickness of 102.5mm will be cooled by a pair of 1.5 W at 4.2 K small coolers. This paper will introduce the updated engineering design of the coupling magnet made by ICST in China. The detailed analyses on magnetic fields, stresses induced during the processes of winding, cool down and charging, and cold mass support assembly are presented as well.

  20. High Magnetic field generation for laser-plasma experiments

    SciTech Connect

    Pollock, B B; Froula, D H; Davis, P F; Ross, J S; Fulkerson, S; Bower, J; Satariano, J; Price, D; Glenzer, S H

    2006-05-01

    An electromagnetic solenoid was developed to study the effect of magnetic fields on electron thermal transport in laser plasmas. The solenoid, which is driven by a pulsed power system suppling 30 kJ, achieves magnetic fields of 13 T. The field strength was measured on the solenoid axis with a magnetic probe and optical Zeeman splitting. The measurements agree well with analytical estimates. A method for optimizing the solenoid design to achieve magnetic fields exceeding 20 T is presented.

  1. Effect of superconducting solenoid model cores on spanwise iron magnet roll control

    NASA Technical Reports Server (NTRS)

    Britcher, C. P.

    1985-01-01

    Compared with conventional ferromagnetic fuselage cores, superconducting solenoid cores appear to offer significant reductions in the projected cost of a large wind tunnel magnetic suspension and balance system. The provision of sufficient magnetic roll torque capability has been a long-standing problem with all magnetic suspension and balance systems; and the spanwise iron magnet scheme appears to be the most powerful system available. This scheme utilizes iron cores which are installed in the wings of the model. It was anticipated that the magnetization of these cores, and hence the roll torque generated, would be affected by the powerful external magnetic field of the superconducting solenoid. A preliminary study has been made of the effect of the superconducting solenoid fuselage model core concept on the spanwise iron magnet roll torque generation schemes. Computed data for one representative configuration indicate that reductions in available roll torque occur over a range of applied magnetic field levels. These results indicate that a 30-percent increase in roll electromagnet capacity over that previously determined will be required for a representative 8-foot wind tunnel magnetic suspension and balance system design.

  2. NdFeB Magnets Aligned in a 9-T Superconducting Solenoid (asterisk)

    NASA Astrophysics Data System (ADS)

    Mulcahy, T. M.; Hull, J. R.

    2002-08-01

    Commercial-grade magnet powder (Magnequench UG) was uniaxial die-pressed into cylindrical compacts, while being aligned in the 1-T to 8-T DC field of a superconducting solenoid at Argonne National Laboratory. Then, the compacts were added to normal Magnequench UG production batches for sintering and annealing. The variations in magnet properties for different strengths of alignment fields are reported for 15.88-mm (5/8-in.) diameter compacts made with length-to-diameter (L/D) ratios in the range 3 0.25 and L 1. The best magnets were produced when the powder-filled die was inserted into the active field of the solenoid and then pressed. Improvements in the residual flux density of 8% and in the energy product of 16% were achieved by increasing the alignment field beyond the typical 2-T capabilities of electromagnets. The most improvement was achieved for the compacts with the smallest L/D ratio. The ability to make very strong magnets with small L/D, where self-demagnetization effects during alignment are greatest, would benefit most the production of near-final-shape magnets. Compaction of the magnet powder using a horizontal die and a continuously active superconducting solenoid was not a problem. Although the press was operated in the batch mode for this proof-of-concept study, its design is intended to enable automated production.

  3. A solenoidal synthetic field and the non-Abelian Aharonov-Bohm effects in neutral atoms

    NASA Astrophysics Data System (ADS)

    Huo, Ming-Xia; Nie, Wei; Hutchinson, David A. W.; Kwek, Leong Chuan

    2014-08-01

    Cold neutral atoms provide a versatile and controllable platform for emulating various quantum systems. Despite efforts to develop artificial gauge fields in these systems, realizing a unique ideal-solenoid-shaped magnetic field within the quantum domain in any real-world physical system remains elusive. Here we propose a scheme to generate a ``hairline'' solenoid with an extremely small size around 1 micrometer which is smaller than the typical coherence length in cold atoms. Correspondingly, interference effects will play a role in transport. Despite the small size, the magnetic flux imposed on the atoms is very large thanks to the very strong field generated inside the solenoid. By arranging different sets of Laguerre-Gauss (LG) lasers, the generation of Abelian and non-Abelian SU(2) lattice gauge fields is proposed for neutral atoms in ring- and square-shaped optical lattices. As an application, interference patterns of the magnetic type-I Aharonov-Bohm (AB) effect are obtained by evolving atoms along a circle over several tens of lattice cells. During the evolution, the quantum coherence is maintained and the atoms are exposed to a large magnetic flux. The scheme requires only standard optical access, and is robust to weak particle interactions.

  4. A solenoidal synthetic field and the non-Abelian Aharonov-Bohm effects in neutral atoms.

    PubMed

    Huo, Ming-Xia; Nie, Wei; Hutchinson, David A W; Kwek, Leong Chuan

    2014-08-08

    Cold neutral atoms provide a versatile and controllable platform for emulating various quantum systems. Despite efforts to develop artificial gauge fields in these systems, realizing a unique ideal-solenoid-shaped magnetic field within the quantum domain in any real-world physical system remains elusive. Here we propose a scheme to generate a "hairline" solenoid with an extremely small size around 1 micrometer which is smaller than the typical coherence length in cold atoms. Correspondingly, interference effects will play a role in transport. Despite the small size, the magnetic flux imposed on the atoms is very large thanks to the very strong field generated inside the solenoid. By arranging different sets of Laguerre-Gauss (LG) lasers, the generation of Abelian and non-Abelian SU(2) lattice gauge fields is proposed for neutral atoms in ring- and square-shaped optical lattices. As an application, interference patterns of the magnetic type-I Aharonov-Bohm (AB) effect are obtained by evolving atoms along a circle over several tens of lattice cells. During the evolution, the quantum coherence is maintained and the atoms are exposed to a large magnetic flux. The scheme requires only standard optical access, and is robust to weak particle interactions.

  5. A solenoidal synthetic field and the non-Abelian Aharonov-Bohm effects in neutral atoms

    PubMed Central

    Huo, Ming-Xia; Nie, Wei; Hutchinson, David A. W.; Kwek, Leong Chuan

    2014-01-01

    Cold neutral atoms provide a versatile and controllable platform for emulating various quantum systems. Despite efforts to develop artificial gauge fields in these systems, realizing a unique ideal-solenoid-shaped magnetic field within the quantum domain in any real-world physical system remains elusive. Here we propose a scheme to generate a “hairline” solenoid with an extremely small size around 1 micrometer which is smaller than the typical coherence length in cold atoms. Correspondingly, interference effects will play a role in transport. Despite the small size, the magnetic flux imposed on the atoms is very large thanks to the very strong field generated inside the solenoid. By arranging different sets of Laguerre-Gauss (LG) lasers, the generation of Abelian and non-Abelian SU(2) lattice gauge fields is proposed for neutral atoms in ring- and square-shaped optical lattices. As an application, interference patterns of the magnetic type-I Aharonov-Bohm (AB) effect are obtained by evolving atoms along a circle over several tens of lattice cells. During the evolution, the quantum coherence is maintained and the atoms are exposed to a large magnetic flux. The scheme requires only standard optical access, and is robust to weak particle interactions. PMID:25103877

  6. A single-solenoid pulsed-magnet system for single-crystal scattering studies.

    PubMed

    Islam, Zahirul; Capatina, Dana; Ruff, Jacob P C; Das, Ritesh K; Trakhtenberg, Emil; Nojiri, Hiroyuki; Narumi, Yasuo; Welp, Ulrich; Canfield, Paul C

    2012-03-01

    We present a pulsed-magnet system that enables x-ray single-crystal diffraction in addition to powder and spectroscopic studies with the magnetic field applied on or close to the scattering plane. The apparatus consists of a single large-bore solenoid, cooled by liquid nitrogen. A second independent closed-cycle cryostat is used for cooling samples near liquid helium temperatures. Pulsed magnetic fields close to ~30 T with a zero-to-peak-field rise time of ~2.9 ms are generated by discharging a 40 kJ capacitor bank into the magnet coil. The unique characteristic of this instrument is the preservation of maximum scattering angle (~23.6°) on the entrance and exit sides of the magnet bore by virtue of a novel double-funnel insert. This instrument will facilitate x-ray diffraction and spectroscopic studies that are impractical, if not impossible, to perform using split-pair and narrow-opening solenoid magnets. Furthermore, it offers a practical solution for preserving optical access in future higher-field pulsed magnets.

  7. Ion acceleration in a solenoid-free plasma expanded by permanent magnets

    SciTech Connect

    Takahashi, K.; Oguni, K.; Yamada, H.; Fujiwara, T.

    2008-08-15

    Ion acceleration is achieved in a low-pressure solenoid-free plasma expanded by permanent magnet arrays. Although a permanent magnet normally forms cusp magnetic fields which prevents plasma diffusion and double layer formation, by employing double concentric arrays of permanent magnets, a constant field area, and a diverging magnetic field can be generated near the outlet of the plasma source. In the source, a rapid potential drop with 4 cm thickness from 50 V to 20 V is generated at the diverging field area for 0.35 mTorr and a supersonic ion beam accelerated through the potential drop is observed in the diffusion chamber. The beam energy can be increased up to over 40 eV with a decrease in gas pressure.

  8. Progress on Design and Construction of a MuCool Coupling Solenoid Magnet

    SciTech Connect

    Wang, L.; Liu, Xiao Kun; Xu, FengYu; Li, S.; Pan, Heng; Wu, Hong; Guo, Xinglong; Zheng, ShiXian; Li, Derun; Virostek, Steve; Zisman, Mike; Green, M.A.

    2010-06-28

    The MuCool program undertaken by the US Neutrino Factory and Muon Collider Collaboration is to study the behavior of muon ionization cooling channel components. A single superconducting coupling solenoid magnet is necessary to pursue the research and development work on the performance of high gradient, large size RF cavities immersed in magnetic field, which is one of the main challenges in the practical realization of ionization cooling of muons. The MuCool coupling magnet is to be built using commercial copper based niobium titanium conductors and cooled by two cryo-coolers with each cooling capacity of 1.5 W at 4.2 K. The solenoid magnet will be powered by using a single 300A power supply through a single pair of binary leads that are designed to carry a maximum current of 210A. The magnet is to be passively protected by cold diodes and resistors across sections of the coil and by quench back from the 6061 Al mandrel in order to lower the quench voltage and the hot spot temperature. The magnet is currently under construction. This paper presents the updated design and fabrication progress on the MuCool coupling magnet.

  9. Superconducting Solenoid and Press for Permanent Magnet Fabrication

    NASA Astrophysics Data System (ADS)

    Mulcahy, T. M.; Hull, J. R.

    2002-08-01

    For the first time, a superconducting solenoid (SCM) was used to increase the remnant magnetization of sintered NdFeB permanent magnets (PMs). In particular, improved magnetic alignment of commercial-grade PM powder was achieved, as it was axial die pressed into 12.7-mm diameter cylindrical compacts in the 76.2-mm warm bore of a 9-T SCM. The press used to compact the powder is unique and was specifically designed for use with the SCM. Although the press was operated in the batch mode for this proof of concept study, its design is intended to enable automated production. In operation, a simple die and punch set made of nonmagnetic materials was filled with powder and loaded into a nonmagnetic press tube. The cantilevered press tube was inserted horizontally, on a carrier manually advanced along a track, into the SCM. The robustness of the mechanical components and the SCM, in its liquid helium dewar, were specifically designed to allow for insertion and extraction of the magnetic powder and compacts, while operating at 9 T.

  10. Superconducting solenoid magnet of the DCBA-T3 experiment searching for neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Kawai, M.; Kondou, Y.; Makida, Y.; Haruyama, T.; Ishihara, N.; Kobayashi, Y.; Iwai, G.; Iwase, H.; Ohama, T.; Takahashi, K.; Yamada, Y.; Kato, Y.; Tanaka, K.; Tonooka, M.; Kitamura, S.; Ishikawa, T.; Igarashi, H.; Kakuno, H.; Sumiyoshi, T.; Tajima, T.; Ishizuka, T.; Ito, R.; Tamura, N.

    2014-03-01

    The experiment of neutrinoless double beta decay (0ν β β) is the only realistic method for investigating the Majorana nature and the absolute mass scale of neutrinos. An R&D project called Drift Chamber Beta-ray Analyzer (DCBA) has been developing a magnetic tracking detector for 0ν β β experiments at KEK. A superconducting solenoid magnet (SCSM) has been constructed to produce a uniform magnetic field for the prototype test facility called DCBA-T3. The results of SCSM test runs are described, as well as its design studies. Since the SCSM is a prototype magnet for a future detector temporarily called Magnetic Tracking Detector (MTD), it is essential to understand its long-term operation. The experience of about two years of operation is also described.

  11. Design, Fabrication, and Test of a Superconducting Dipole Magnet Based on Tilted Solenoids

    SciTech Connect

    Caspi, S.; Dietderich, D. R.; Ferracin, P.; Finney, N. R.; Fuery, M. J.; Gourlay, S. A.; Hafalia, A. R.

    2007-06-01

    It can be shown that, by superposing two solenoid-like thin windings that are oppositely skewed (tilted) with respect to the bore axis, the combined current density on the surface is 'cos-theta' like and the resulting magnetic field in the bore is a pure dipole. As a proof of principle, such a magnet was designed, built and tested as part of a summer undergraduate intern project. The measured field in the 25mm bore, 4 single strand layers using NbTi superconductor, exceeded 1 T. The simplicity of this high field quality design, void of typical wedges end-spacers and coil assembly, is especially suitable for insert-coils using High Temperature Superconducting wire as well as for low cost superconducting accelerator magnets for High Energy Physics. Details of the design, construction and test are reported.

  12. LCLS Gun Solenoid Design Considerations

    SciTech Connect

    Schmerge, John

    2010-12-10

    The LCLS photocathode rf gun requires a solenoid immediately downstream for proper emittance compensation. Such a gun and solenoid have been operational at the SSRL Gun Test Facility (GTF) for over eight years. Based on magnetic measurements and operational experience with the GTF gun solenoid multiple modifications are suggested for the LCLS gun solenoid. The modifications include adding dipole and quadrupole correctors inside the solenoid, increasing the bore to accommodate the correctors, decreasing the mirror plate thickness to allow the solenoid to move closer to the cathode, cutouts in the mirror plate to allow greater optical clearance with grazing incidence cathode illumination, utilizing pancake coil mirror images to compensate the first and second integrals of the transverse fields and incorporating a bipolar power supply to allow for proper magnet standardization and quick polarity changes. This paper describes all these modifications plus the magnetic measurements and operational experience leading to the suggested modifications.

  13. Beam collimation and transport of quasineutral laser-accelerated protons by a solenoid field

    NASA Astrophysics Data System (ADS)

    Harres, K.; Alber, I.; Tauschwitz, A.; Bagnoud, V.; Daido, H.; Günther, M.; Nürnberg, F.; Otten, A.; Schollmeier, M.; Schütrumpf, J.; Tampo, M.; Roth, M.

    2010-02-01

    This article reports about controlling laser-accelerated proton beams with respect to beam divergence and energy. The particles are captured by a pulsed high field solenoid with a magnetic field strength of 8.6 T directly behind a flat target foil that is irradiated by a high intensity laser pulse. Proton beams with energies around 2.3 MeV and particle numbers of 1012 could be collimated and transported over a distance of more than 300 mm. In contrast to the protons the comoving electrons are strongly deflected by the solenoid field. They propagate at a submillimeter gyroradius around the solenoid's axis which could be experimentally verified. The originated high flux electron beam produces a high space charge resulting in a stronger focusing of the proton beam than expected by tracking results. Leadoff particle-in-cell simulations show qualitatively that this effect is caused by space charge attraction due to the comoving electrons. The collimation and transport of laser-accelerated protons is the first step to provide these unique beams for further applications such as postacceleration by conventional accelerator structures.

  14. Design features of the solenoid magnets for the central cell of the MFTF-B

    SciTech Connect

    Wohlwend, J.W.; Tatro, R.E.; Ring, D.S.

    1981-10-23

    The 14 superconducting solenoid magnets which form the central cell of the MFTF-B are being designed and fabricated by General Dynamics for the Lawrence Livermore National Laboratory. Each solenoid coil has a mean diameter of five meters and contains 600 turns of a proven conductor type. Structural loading resulting from credible fault events, cooldown and warmup requirements, and manufacturing processes consistent with other MFTF-B magnets have been considered in the selection of 304 LN as the structural material for the magnet. The solenoid magnets are connected by 24 intercoil beams and 20 solid struts which resist the longitudinal seismic and electromagnetic attractive forces and by 24 hanger/side supports which react magnet dead weight and seismic loads. A modular arrangement of two solenoid coils within a vacuum vessel segment allow for sequential checkout and installation.

  15. An implantable RF solenoid for magnetic resonance microscopy and microspectroscopy.

    PubMed

    Rivera, D S; Cohen, M S; Clark, W G; Chu, A C; Nunnally, R L; Smith, J; Mills, D; Judy, J W

    2012-08-01

    Miniature solenoids routinely enhance small volume nuclear magnetic resonance imaging and spectroscopy; however, no such techniques exist for patients. We present an implantable microcoil for diverse clinical applications, with a microliter coil volume. The design is loosely based on implantable depth electrodes, in which a flexible tube serves as the substrate, and a metal stylet is inserted into the tube during implantation. The goal is to provide enhanced signal-to-noise ratio (SNR) of structures that are not easily accessed by surface coils. The first-generation prototype was designed for implantation up to 2 cm, and provided initial proof-of-concept for microscopy. Subsequently, we optimized the design to minimize the influence of lead inductances, and to thereby double the length of the implantable depth (4 cm). The second-generation design represents an estimated SNR improvement of over 30% as compared to the original design when extended to 4 cm. Impedance measurements indicate that the device is stable for up to 24 h in body temperature saline. We evaluated the SNR and MR-related heating of the device at 3T. The implantable microcoil can differentiate fat and water peaks, and resolve submillimeter features.

  16. Jefferson Lab CLAS12 Superconducting Solenoid magnet Requirements and Design Evolution

    SciTech Connect

    Rajput-Ghoshal, Renuka; Hogan, John P.; Fair, Ruben J.; Ghoshal, Probir K.; Luongo, Cesar; Elouadrhiri, Latifa

    2014-12-01

    As part of the Jefferson Lab 12GeV accelerator upgrade project, one of the experimental halls (Hall B) requires two superconducting magnets. One is a magnet system consisting of six superconducting trapezoidal racetrack-type coils assembled in a toroidal configuration and the second is an actively shielded solenoidal magnet system consisting of 5 coils. In this presentation the physics requirements for the 5 T solenoid magnet, design constraints, conductor decision, and cooling choice will be discussed. The various design iterations to meet the specification will also be discussed in this presentation.

  17. Electromagnetic field distribution calculation in solenoidal inductively coupled plasma using finite difference method

    SciTech Connect

    Li, W. P.; Liu, Y.; Long, Q.; Chen, D. H.; Chen, Y. M.

    2008-10-15

    The electromagnetic field (both E and B fields) is calculated for a solenoidal inductively coupled plasma (ICP) discharge. The model is based on two-dimensional cylindrical coordinates, and the finite difference method is used for solving Maxwell equations in both the radial and axial directions. Through one-turn coil measurements, assuming that the electrical conductivity has a constant value in each cross section of the discharge tube, the calculated E and B fields rise sharply near the tube wall. The nonuniform radial distributions imply that the skin effect plays a significant role in the energy balance of the stable ICP. Damped distributions in the axial direction show that the magnetic flux gradually dissipates into the surrounding space. A finite difference calculation allows prediction of the electrical conductivity and plasma permeability, and the induction coil voltage and plasma current can be calculated, which are verified for correctness.

  18. Solenoid Compensation for the SuperB Interaction Region

    SciTech Connect

    Bertsche, Kirk; Sullivan, Michael K.; /SLAC

    2010-08-25

    We present an approach for compensating adverse effects of the detector solenoid in the SuperB Interaction Region (IR). We place compensating solenoids around the IR quadrupole magnets to reduce the magnetic fields nearly to zero. This allows more operational headroom for superconducting IR magnets and avoids saturation of ferric IR magnets. We place stronger compensating solenoids between IR magnets to reverse the magnetic field direction. This allows adjusting the total integrated solenoid field to zero, which eliminates coordinate plane rotation and reduces vertical beam displacements in the IR.

  19. Performance measurements of a pilot superconducting solenoid model core for a wind tunnel magnetic suspension and balance system

    NASA Technical Reports Server (NTRS)

    Goodyer, M. J.; Britcher, C. P.

    1983-01-01

    The results of experimental demonstrations of a superconducting solenoid model core in the Southampton University Magnetic Suspension and Balance System are detailed. Technology and techniques relevant to large-scale wind tunnel MSBSs comprise the long term goals. The magnetic moment of solenoids, difficulties peculiar to superconducting solenoid cores, lift force and pitching moment, dynamic lift calibration, and helium boil-off measurements are discussed.

  20. Electrons in a positive-ion beam with solenoid or quadrupole magnetic transport

    SciTech Connect

    Molvik, A.W.; Kireeff Covo, M.; Cohen, R.; Coleman, J.; Sharp, W.; Bieniosek, F.; Friedman, A.; Roy, P.K.; Seidl, P.; Lund, S.M.; Faltens, A.; Vay, J.L.; Prost, L.

    2007-06-04

    The High Current Experiment (HCX) is used to study beam transport and accumulation of electrons in quadrupole magnets and the Neutralized Drift-Compression Experiment (NDCX) to study beam transport through and accumulation of electrons in magnetic solenoids. We find that both clearing and suppressor electrodes perform as intended, enabling electron cloud densities to be minimized. Then, the measured beam envelopes in both quadrupoles and solenoids agree with simulations, indicating that theoretical beam current transport limits are reliable, in the absence of electrons. At the other extreme, reversing electrode biases with the solenoid transport effectively traps electrons; or, in quadrupole magnets, grounding the suppressor electrode allows electron emission from the end wall to flood the beam, in both cases producing significant degradation in the beam.

  1. Electrons in a Positive-Ion Beam with Solenoid or Quadrupole Magnet Transport

    SciTech Connect

    Molvik, A W; Cohen, R H; Friedman, A; Covo, M K; Lund, S M; Sharp, W M; Seidl, P A; Bieniosek, F M; Coleman, J E; Faltens, A; Roy, P K; Vay, J L; Prost, L

    2007-06-01

    The High Current Experiment (HCX) is used to study beam transport and accumulation of electrons in quadrupole magnets and the Neutralized Drift-Compression Experiment (NDCX) to study beam transport through and accumulation of electrons in magnetic solenoids. We find that both clearing and suppressor electrodes perform as intended, enabling electron cloud densities to be minimized. Then, the measured beam envelopes in both quadrupoles and solenoids agree with simulations, indicating that theoretical beam current transport limits are reliable, in the absence of electrons. At the other extreme, reversing electrode biases with the solenoid transport effectively traps electrons; or, in quadrupole magnets, grounding the suppressor electrode allows electron emission from the end wall to flood the beam, in both cases producing significant degradation in the beam.

  2. Plasma confinement apparatus using solenoidal and mirror coils

    DOEpatents

    Fowler, T. Kenneth; Condit, William C.

    1979-01-01

    A plasma confinement apparatus, wherein multiple magnetic mirror cells are linked by magnetic field lines inside of a solenoid with the mirroring regions for adjacent magnetic mirror cells each formed by a separate mirror coil inside of the solenoid. The magnetic mirror cells may be field reversed.

  3. A feasibility study of high-strength Bi-2223 conductor for high-field solenoids

    NASA Astrophysics Data System (ADS)

    Godeke, A.; Abraimov, D. V.; Arroyo, E.; Barret, N.; Bird, M. D.; Francis, A.; Jaroszynski, J.; Kurteva, D. V.; Markiewicz, W. D.; Marks, E. L.; Marshall, W. S.; McRae, D. M.; Noyes, P. D.; Pereira, R. C. P.; Viouchkov, Y. L.; Walsh, R. P.; White, J. M.

    2017-03-01

    We performed a feasibility study on a high-strength Bi{}2-xPb x Sr2Ca2Cu3O{}10-x(Bi-2223) tape conductor for high-field solenoid applications. The investigated conductor, DI-BSCCO Type HT-XX, is a pre-production version of Type HT-NX, which has recently become available from Sumitomo Electric Industries. It is based on their DI-BSCCO Type H tape, but laminated with a high-strength Ni-alloy. We used stress–strain characterizations, single- and double-bend tests, easy- and hard-way bent coil-turns at various radii, straight and helical samples in up to 31.2 T background field, and small 20-turn coils in up to 17 T background field to systematically determine the electro-mechanical limits in magnet-relevant conditions. In longitudinal tensile tests at 77 K, we found critical stress- and strain-levels of 516 MPa and 0.57%, respectively. In three decidedly different experiments we detected an amplification of the allowable strain with a combination of pure bending and Lorentz loading to ≥slant 0.92 % (calculated elastically at the outer tape edge). This significant strain level, and the fact that it is multi-filamentary conductor and available in the reacted and insulated state, makes DI-BSCCO HT-NX highly suitable for very high-field solenoids, for which high current densities and therefore high loads are required to retain manageable magnet dimensions.

  4. The IRAC Shutter Mechanism: Residual Magnetism and the Rotary Solenoid

    NASA Technical Reports Server (NTRS)

    Schwinger, Scott; Hakun, Claef; Brown, Gary; Blumenstock, Ken

    2002-01-01

    The Infrared Array Camera (IRAC) Shutter mechanism was originally presented in the paper, 'A Low Power Cryogenic Shutter Mechanism for Use on Infrared Imagers' at the 34th Aerospace Mechanisms Symposium, May 2000. At that time, the shutter was believed to be performing flawlessly and there was every indication it would continue to do so. In early spring of 2001, the calibration shutter, a rotary solenoid designed to be fail-safe open, remained in a closed state with no power to the electromagnetic coils. The ensuing investigation, subsequent testing, proposed remedy, and lessons learned are the focus of this paper.

  5. The Mechanical and Thermal Design for the MICE Coupling SolenoidMagnet

    SciTech Connect

    Green, M.A.; Yang, S.Q.; Bravar, U.; Lau, W.; Li, D.; Strauss,B.P.; Virostek, S.P.; White, A.E.; Witte, H.

    2004-09-20

    The MICE coupling solenoids surround the RF cavities that are used to increase the longitudinal momentum of the muon beam that is being cooled within MICE. The coupling solenoids will have a warm-bore diameter of 1394 mm. This is the warm bore that is around the 200 MHz RF cavities. The coupling solenoid is a single superconducting coil fabricated from a copper matrix Nb-Ti conductor originally designed for MRI magnets. A single coupling magnet is designed so that it can be cooled with a single 1.5 W (at 4.2 K) cooler. The MICE cooling channel has two of these solenoids, which will be hooked together in series, for a magnet circuit with a total stored-energy of the order of 12.8 MJ. Quench protection for the coupling coils is discussed. This report also presents the mechanical and thermal design parameters for this magnet, including the results of finite element calculations of mechanical forces and heat flow in the magnet cold mass.

  6. Design and Construction of a Prototype Solenoid Coil for MICE Coupling Magnets

    SciTech Connect

    Wang, Li; Pan, Heng; Guo, XingLong; Xu, FengYu; Liu, XiaoKun; Wu, Hong; Zheng, ShiXian; Green, Michael A; Li, Derun; Virostek, Steve; Zisman, Michael

    2010-06-28

    A superconducting coupling solenoid mounted around four conventional RF cavities, which produces up to 2.6 T central magnetic field to keep the muons within the cavities, is to be used for the Muon Ionization Cooling Experiment (MICE). The coupling coil made from copper matrix NbTi conductors is the largest of three types of magnets in MICE both in terms of 1.5 m inner diameter and about 13MJ stored magnetic energy at full operation current of 210A. The stress induced inside the coil assembly during cool down and magnet charging is relatively high. In order to validate the design method and develop the coil winding technique with inside-wound SC splices required for the coupling coil, a prototype coil made from the same conductor and with the same diameter and thickness but only one-fourth long as the coupling coil was designed and fabricated by ICST. The prototype coil was designed to be charged to strain conditions that are equivalent or greater than would be encountered in the coupling coil. This paper presents detailed design of the prototype coil as well as developed coil winding skills. The analyses on stress in the coil assembly and quench process were carried out.

  7. Design of High Field Solenoids made of High Temperature Superconductors

    SciTech Connect

    Bartalesi, Antonio; /Pisa U.

    2010-12-01

    This thesis starts from the analytical mechanical analysis of a superconducting solenoid, loaded by self generated Lorentz forces. Also, a finite element model is proposed and verified with the analytical results. To study the anisotropic behavior of a coil made by layers of superconductor and insulation, a finite element meso-mechanic model is proposed and designed. The resulting material properties are then used in the main solenoid analysis. In parallel, design work is performed as well: an existing Insert Test Facility (ITF) is adapted and structurally verified to support a coil made of YBa{sub 2}Cu{sub 3}O{sub 7}, a High Temperature Superconductor (HTS). Finally, a technological winding process was proposed and the required tooling is designed.

  8. Design and Construction of Test Coils for the MICE Coupling Solenoid Magnet

    SciTech Connect

    Wang, Li; Pan, Heng; Xu, F.Y.; Liu, XioaKun; Chen, AnBin; Li, LanKai; Gou, XingLong; Wu, Hong; Green, Michael; Li, Darun; Strauss, Bruce

    2008-08-08

    The superconducting coupling solenoid to be applied in the Muon Ionization Cooling Experiment (MICE) is made from copper matrix Nb-Ti conductors with inner radius of 750 mm, length of 285 mm and thickness of 102.5 mm at room temperature. The magnetic field up to 2.6 T at the magnet centerline is to keep the muons within the MICE RF cavities. Its self inductance is around 592 H and its magnet stored energy is about 13 MJ at a full current of 210 A for the worst operation case of the MICE channel. The stress induced inside the coil during cool down and charging is relatively high. Two test coils are to build and test in order to validate the design method and develop the fabrication technique required for the coupling coil winding, one is 350 mm inner diameter and full length same as the coupling coil, and the other is one-quarter length and 1.5 m diameter. The 1.5 m diameter coil will be charged to strain conditions that are greater than would be encountered in the coupling coil. This paper presents detailed design of the test coils as well as developed winding skills. The analyses on stress in coil assemblies, AC loss, and quench process are carried out.

  9. The Mechanical and Thermal Design for the MICE Focusing SolenoidMagnet System

    SciTech Connect

    Yang, S.Q.; Green, M.A.; Barr, G.; Bravar, U.; Cobb, J.; Lau, W.; Senanayake, R.S.; White, A.E.; Witte, H.

    2004-05-07

    The focusing solenoids for MICE surround energy absorbers that are used to reduce the transverse momentum of the muon beam that is being cooled within MICE. The focusing solenoids will have a warm-bore diameter of 470 mm. Within this bore is a flask of liquid hydrogen or a room temperature beryllium absorber. The focusing solenoid consists of two coils wound with a copper matrix Nb-Ti conductor originally designed for MRI magnets. The two coils have separate leads, so that they may be operated at the same polarity or at opposite polarity. The focusing magnet is designed so that it can be cooled with a pair of 1.5 W (at 4.2 K) coolers. The MICE cooling channel has three focusing magnets with their absorbers. The three focusing magnets will be hooked together in series for a circuit stored-energy of about 9.0 MJ. Quench protection for the focusing magnets is discussed. This report presents the mechanical and thermal design parameters for this magnet, including the results of finite element calculations of mechanical forces and heat flow in the magnet cold mass.

  10. EFFECT OF SOLENOID FIELD ERRORS ON ELECTRON BEAM TEMPERATURES IN THE RHIC ELECTRON COOLER.

    SciTech Connect

    MONTAG,C.KEWISCH,J.

    2003-05-12

    As part of a future upgrade to the Relativistic Heavy Ion Collider (RHIC), electron cooling is foreseen to decrease ion beam emittances. Within the electron cooling section, the ''hot'' ion beam is immersed in a ''cold'' electron beam. The cooling effect is further enhanced by a solenoid field in the cooling section, which forces the electrons to spiral around the field lines with a (Larmor) radius of 10 micrometers, reducing the effective transverse temperature by orders of magnitude. Studies of the effect of solenoid field errors on electron beam temperatures are reported.

  11. 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.

  12. Magnetic Fields at the Center of Coils

    ERIC Educational Resources Information Center

    Binder, Philippe; Hui, Kaleonui; Goldman, Jesse

    2014-01-01

    In this note we synthesize and extend expressions for the magnetic field at the center of very short and very long current-carrying coils. Elementary physics textbooks present the following equation for the magnetic field inside a very long current-carrying coil (solenoid): B[subscript sol] = µ[subscript 0] (N/L) I, (1) where I is the current, N…

  13. Progress on the MICE Tracker Solenoid

    SciTech Connect

    Green, Michael A.; Virostek, Steve P.; Lau, W.; Yang, Stephanie Q.

    2006-06-10

    This report describes the 400 mm warm bore tracker solenoid for the Muon Ionization Cooling Experiment (MICE). The 2.923 m long tracker solenoid module includes the radiation shutter between the end absorber focus coil modules and the tracker as well as the 2.735 m long magnet cryostat vacuum vessel. The 2.554 m long tracker solenoid cold mass consists of two sections, a three-coil spectrometer magnet and a two-coil matching section that matches the uniform field 4 T spectrometer solenoid into the MICE cooling channel. The two tracker magnets are used to provide a uniform magnetic field for the fiber detectors that are used to measure the muon beam emittance at the two ends of the cooling channel. This paper describes the design for the tracker magnet coils and the 4.2 K cryogenic coolers that are used to cool the superconducting magnet. Interfaces between the magnet and the detectors are discussed.

  14. Improving sintered NdFeB permanent magnets by powder compaction in a 9 T superconducting solenoid

    NASA Astrophysics Data System (ADS)

    Mulcahy, T. M.; Hull, J. R.; Rozendaal, E.; Wise, J. H.; Turner, L. R.

    2003-05-01

    Commercial-grade magnet powder (Magnequench UG) was axial die pressed in the 76.2 mm warm bore of a 9 T superconducting solenoid. Otherwise, processing was performed as part of normal factory operations. This pressing was done to improve the alignment of the anisotropic single-crystal particles of the compact and, thus, the remanent magnetization of the sintered cylindrical permanent magnets (12.7 mm diameter). Although the press was operated in batch mode for this proof-of-concept study, its design enables automated production. Improvements of up to 8% in magnetization and 16% in energy products were obtained, as the alignment field H was increased above the 2 T maximum field of electromagnets used in industry. The greatest improvements were obtained for magnets with the smallest length-to-diameter ratios, L/D<0.5. The production of quality magnets in this near-final-shape size range is currently being pursued by industry to eliminate expensive machining steps. To understand the potential for 2-8 T alignment fields to overcome the distortions created in the otherwise uniform field by the self-field of short compacts, electromagnetic code (Opera) calculations were made. A simple material model was used to predict the distortions. The trends in the predicted field-line inclinations, with L/D and H, compare to trends in the improvement of the magnetic properties.

  15. High-field superconducting nested coil magnet

    NASA Technical Reports Server (NTRS)

    Laverick, C.; Lobell, G. M.

    1970-01-01

    Superconducting magnet, employed in conjunction with five types of superconducting cables in a nested solenoid configuration, produces total, central magnetic field strengths approaching 70 kG. The multiple coils permit maximum information on cable characteristics to be gathered from one test.

  16. Numerical analysis of magnetic field in superconducting magnetic energy storage

    SciTech Connect

    Kanamaru, Y. ); Amemiya, Y. )

    1991-09-01

    This paper reports that the superconducting magnetic energy storage (SMES) is more useful than the other systems of electric energy storage because of larger stored energy and higher efficiency. The other systems are the battery, the flywheel, the pumped-storage power station. Some models of solenoid type SMES are designed in U.S.A. and Japan. But a high magnetic field happens by the large scale SMES in the living environment, and makes the erroneous operations of the computer display, the pacemaker of the heart and the electronic equipments. We study some fit designs of magnetic shielding of the solenoidal type SMES for reduction of the magnetic field in living environment. When some superconducting shielding coils are over the main storage coil, magnetic field reduces remarkably than the case of non shielding coil. The calculated results of the magnetic field are obtained y the finite element method.

  17. Commissioning and Testing the 1970's Era LASS Solenoid Magnet in JLab's Hall D

    SciTech Connect

    Ballard, Joshua T.; Biallas, George H.; Brown, G.; Butler, David E.; Carstens, Thomas J.; Chudakov, Eugene A.; Creel, Jonathan D.; Egiyan, Hovanes; Martin, F.; Qiang, Yi; Smith, Elton S.; Stevens, Mark A.; Spiegel, Scot L.; Whitlatch, Timothy E.; Wolin, Elliott J.; Ghoshal, Probir K.

    2015-06-01

    JLab refurbished and reconfigured the LASS1, 1.85m bore Solenoid and installed it as the principal analysis magnet for nuclear physics in the newly constructed, Hall D at Jefferson Lab. The magnet contains four superconducting coils within an iron yoke. The magnet was built in the early1970's at Stanford Linear Accelerator Center and used a second time at Los Alamos National Laboratory. The coils were extensively refurbished and individually tested by JLab. A new Cryogenic Distribution Box provides cryogens and their control valving, current distribution bus, and instrumentation pass-through. A repurposed CTI 2800 refrigerator system and new transfer line complete the system. We describe the re-configuration, the process and problems of re-commissioning the magnet and the results of testing the completed magnet.

  18. The Design Parameters for the MICE Tracker Solenoid

    SciTech Connect

    Green, Michael A.; Chen, C.Y.; Juang, Tiki; Lau, Wing W.; Taylor,Clyde; Virostek, Steve P.; Wahrer, Robert; Wang, S.T.; Witte, Holger; Yang, Stephanie Q.

    2006-08-20

    The first superconducting magnets to be installed in the muon ionization cooling experiment (MICE) will be the tracker solenoids. The tracker solenoid module is a five coil superconducting solenoid with a 400 mm diameter warm bore that is used to provide a 4 T magnetic field for the experiment tracker module. Three of the coils are used to produce a uniform field (up to 4 T with better than 1 percent uniformity) in a region that is 300 mm in diameter and 1000 mm long. The other two coils are used to match the muon beam into the MICE cooling channel. Two 2.94-meter long superconducting tracker solenoid modules have been ordered for MICE. The tracker solenoid will be cooled using two-coolers that produce 1.5 W each at 4.2 K. The magnet system is described. The decisions that drive the magnet design will be discussed in this report.

  19. CRYOGENIC SYSTEM FOR BEPCII SRF CAVITY, IR QUADRUPOLE AND DETECTOR SOLENOID MAGNETS.

    SciTech Connect

    JIA,J.X.; WANG.L.

    2004-05-11

    Beijing Electron-Positron Collider Upgrade (BEPCII) requires three types of superconducting facilities, including one pair of SRF cavities, one pair of interaction region quadrupole magnets, and one detector solenoid magnet. The cryo-plant for BEPCII has a total cooling capacity of 1kW at 4.5K, which is composed of two separate helium refrigerators of 500W each. Two refrigerators share the same gas storage and recovery system. The engineering design for the cryogenic systems, including power leads, control dewars, subcooler, cryogenic valve boxes, cryogenic transfer-lines and cryogenic controls, is completed. The production of its subsystem is under way. This paper summarizes the progress in cryogenics of the BEPCII project.

  20. Build up of electron cloud with different bunch pattern in the presence of solenoidal field

    SciTech Connect

    Cai, Y.; Furman, M.A.; Pivi, M.

    2004-04-01

    We have augmented the code POSINST to include solenoid fields, and used it to simulate the build up of electron cloud due to electron multipacting in the PEP-II positron ring. We find that the distribution of electrons is strongly affected by the resonances associated with the cyclotron period and bunch spacing. In addition, we discover a threshold beyond which the electron density grows exponentially until it reaches the space charge limit. The threshold does not depend on the bunch spacing but does depend on the positron bunch population.

  1. Approximate theory the electromagnetic energy of solenoid in special relativity

    NASA Astrophysics Data System (ADS)

    Prastyaningrum, I.; Kartikaningsih, S.

    2017-01-01

    Solenoid is a device that is often used in electronic devices. A solenoid is electrified will cause a magnetic field. In our analysis, we just focus on the electromagnetic energy for solenoid form. We purpose to analyze by the theoretical approach in special relativity. Our approach is begun on the Biot Savart law and Lorentz force. Special theory relativity can be derived from the Biot Savart law, and for the energy can be derived from Lorentz for, by first determining the momentum equation. We choose the solenoid form with the goal of the future can be used to improve the efficiency of the electrical motor.

  2. Solenoid and monocusp ion source

    SciTech Connect

    Brainard, J.P.; Burns, E.J.T.; Draper, C.H.

    1995-12-31

    An ion source which generates ions having high atomic purity incorporates a solenoidal magnetic field to increase the electron path length. In a sealed envelope, electrons emitted from a cathode traverse the magnetic field lines of a solenoid and a monocusp magnet between the cathode and a reflector at the monocusp. As electrons collide with gas, the molecular gas forms a plasma. An anode grazes the outer boundary of the plasma. Molecular ions and high energy electrons remain substantially on the cathode side of the cusp, but as the ions and electrons are scattered to the aperture side of the cusp, additional collisions create atomic ions. The increased electron path length allows for smaller diameters and lower operating pressures.

  3. Investigation of effect of solenoid magnet on emittances of ion beam from laser ablation plasma

    NASA Astrophysics Data System (ADS)

    Ikeda, Shunsuke; Romanelli, Mark; Cinquegrani, David; Sekine, Megumi; Kumaki, Masafumi; Fuwa, Yasuhiro; Kanesue, Takeshi; Okamura, Masahiro; Horioka, Kazuhiko

    2014-02-01

    A magnetic field can increase an ion current of a laser ablation plasma and is expected to control the change of the plasma ion current. However, the magnetic field can also make some fluctuations of the plasma and the effect on the beam emittance and the emission surface is not clear. To investigate the effect of a magnetic field, we extracted the ion beams under three conditions where without magnetic field, with magnetic field, and without magnetic field with higher laser energy to measure the beam distribution in phase space. Then we compared the relations between the plasma ion current density into the extraction gap and the Twiss parameters with each condition. We observed the effect of the magnetic field on the emission surface.

  4. Investigation of effect of solenoid magnet on emittances of ion beam from laser ablation plasma.

    PubMed

    Ikeda, Shunsuke; Romanelli, Mark; Cinquegrani, David; Sekine, Megumi; Kumaki, Masafumi; Fuwa, Yasuhiro; Kanesue, Takeshi; Okamura, Masahiro; Horioka, Kazuhiko

    2014-02-01

    A magnetic field can increase an ion current of a laser ablation plasma and is expected to control the change of the plasma ion current. However, the magnetic field can also make some fluctuations of the plasma and the effect on the beam emittance and the emission surface is not clear. To investigate the effect of a magnetic field, we extracted the ion beams under three conditions where without magnetic field, with magnetic field, and without magnetic field with higher laser energy to measure the beam distribution in phase space. Then we compared the relations between the plasma ion current density into the extraction gap and the Twiss parameters with each condition. We observed the effect of the magnetic field on the emission surface.

  5. Expanding Non-solenoidal Startup with Local Helicity Injection to Increased Toroidal Field and Helicity Injection Rate

    NASA Astrophysics Data System (ADS)

    Perry, J. M.; Barr, J. L.; Bodner, G. M.; Bongard, M. W.; Burke, M. G.; Fonck, R. J.; Hinson, E. T.; Lewicki, B. T.; Reusch, J. A.; Schlossberg, D. J.; Winz, G. R.

    2015-11-01

    Local helicity injection (LHI) is a non-solenoidal startup technique under development on the Pegasus ST. Plasma currents up to 0.18 MA have been initiated by LHI in conjunction with poloidal field induction. A 0-D power balance model has been developed to predict plasma current evolution by balancing helicity input against resistive dissipation. The model is being validated against a set of experimental measurements and magnetic reconstructions with radically varied plasma geometric evolutions. Outstanding physics issues with LHI startup are the scalings of confinement and MHD activity with helicity injection rate and toroidal field strength, as well as injector behavior at high field. Preliminary results from the newly-installed Thomson scattering system suggest core temperatures of a few hundred eV during LHI startup. Measurements are being expanded to multiple spatial points for ongoing confinement studies. A set of larger-area injectors is being installed in the lower divertor region, where increased toroidal field will provide a helicity injection rate over 3 times that of outboard injectors. In this regime helicity injection will be the dominant current drive. Experiments with divertor injectors will permit experimental differentiation of several possible confinement models, and demonstrate the feasibility of LHI startup at high field. Work supported by US DOE grant DE-FG02-96ER54375.

  6. Solenoid and monocusp ion source

    SciTech Connect

    Brainard, John Paul; Burns, Erskine John Thomas; Draper, Charles Hadley

    1997-01-01

    An ion source which generates hydrogen ions having high atomic purity incorporates a solenoidal permanent magnets to increase the electron path length. In a sealed envelope, electrons emitted from a cathode traverse the magnetic field lines of a solenoid and a monocusp magnet between the cathode and a reflector at the monocusp. As electrons collide with gas, the molecular gas forms a plasma. An anode grazes the outer boundary of the plasma. Molecular ions and high energy electrons remain substantially on the cathode side of the cusp, but as the ions and electrons are scattered to the aperture side of the cusp, additional collisions create atomic ions. The increased electron path length allows for smaller diameters and lower operating pressures.

  7. Solenoid and monocusp ion source

    DOEpatents

    Brainard, J.P.; Burns, E.J.T.; Draper, C.H.

    1997-10-07

    An ion source which generates hydrogen ions having high atomic purity incorporates a solenoidal permanent magnets to increase the electron path length. In a sealed envelope, electrons emitted from a cathode traverse the magnetic field lines of a solenoid and a monocusp magnet between the cathode and a reflector at the monocusp. As electrons collide with gas, the molecular gas forms a plasma. An anode grazes the outer boundary of the plasma. Molecular ions and high energy electrons remain substantially on the cathode side of the cusp, but as the ions and electrons are scattered to the aperture side of the cusp, additional collisions create atomic ions. The increased electron path length allows for smaller diameters and lower operating pressures. 6 figs.

  8. D-zero rototrack: first stage of D-zero 2 Tesla solenoid field mapping device

    SciTech Connect

    Yamada, R.; Korienek, J.; Krider, J.; Lindenmeyer, C.; Miksa, D.; Miksa, R.

    1997-09-01

    A simple and portable field mapping device was developed at Fermilab and successfully used to test the D0 2 Tesla solenoid at Toshiba Works in Japan. A description of the mechanical structure, electric driving and control system, and software of the field mapping device is given. Four Hall probe elements of Group3 Digital Gaussmeters are mounted on the radial extension arm of a carriage, which is mounted on a central rotating beam. The system gives two dimensional motions (axial and rotational) to the Hall probes. To make the system compact and portable, we used a laptop computer with PCMCIA cards. For the control system we used commercially available software LabVIEW and Motion Toolbox, and for the data analysis we used Microsoft Excel.

  9. Beam collimation and energy spectrum compression of laser-accelerated proton beams using solenoid field and RF cavity

    NASA Astrophysics Data System (ADS)

    Teng, J.; Gu, Y. Q.; Zhu, B.; Hong, W.; Zhao, Z. Q.; Zhou, W. M.; Cao, L. F.

    2013-11-01

    This paper presents a new method of laser produced proton beam collimation and spectrum compression using a combination of a solenoid field and a RF cavity. The solenoid collects laser-driven protons efficiently within an angle that is smaller than 12 degrees because it is mounted few millimeters from the target, and collimates protons with energies around 2.3 MeV. The collimated proton beam then passes through a RF cavity to allow compression of the spectrum. Particle-in-cell (PIC) simulations demonstrate the proton beam transport in the solenoid and RF electric fields. Excellent energy compression and collection efficiency of protons are presented. This method for proton beam optimization is suitable for high repetition-rate laser acceleration proton beams, which could be used as an injector for a conventional proton accelerator.

  10. Mu2e production solenoid cryostat conceptual design

    SciTech Connect

    Nicol, T.H.; Kashikhin, V.V.; Page, T.M.; Peterson, T.J.; /Fermilab

    2011-06-01

    Mu2e is a muon-to-electron conversion experiment being designed by an international collaboration of more than 65 scientists and engineers from more than 20 research institutions for installation at Fermilab. The experiment is comprised of three large superconducting solenoid magnet systems, production solenoid (PS), transport solenoid (TS) and detector solenoid (DS). A 25 kW, 8 GeV proton beam strikes a target located in the PS creating muons from the decay of secondary particles. These muons are then focused in the PS and the resultant muon beam is transported through the TS towards the DS. The production solenoid presents a unique set of design challenges as the result of high radiation doses, stringent magnetic field requirements, and large structural forces. This paper describes the conceptual design of the PS cryostat and will include discussions of the vacuum vessel, thermal shield, multi-layer insulation, cooling system, cryogenic piping, and suspension system.

  11. Effect of axial magnetic field on a 2.45 GHz permanent magnet ECR ion source

    SciTech Connect

    Nakamura, T. Wada, H.; Furuse, M.; Asaji, T.

    2016-02-15

    Herein, we conduct a fundamental study to improve the generation efficiency of a multi-charged ion source using argon. A magnetic field of our electron cyclotron resonance ion source is composed of a permanent magnet and a solenoid coil. Thereby, the axial magnetic field in the chamber can be tuned. Using the solenoid coil, we varied the magnetic field strength in the plasma chamber and measured the ion beam current extracted at the electrode. We observed an approximately three times increase in the Ar{sup 4+} ion beam current when the magnetic field on the extractor-electrode side of the chamber was weakened. From our results, we can confirm that the multi-charged ion beam current changes depending on magnetic field intensity in the plasma chamber.

  12. Scattering in a magnetic field

    SciTech Connect

    David C. Carey

    2002-08-19

    The fixed target program at Fermilab has come to an end. New projects are in the planning stage. Among them is a muon storage ring. Up to the present, all storage rings in high-energy physics have carried stable particles, namely the electron and proton and their antiparticles. The muon is unstable and decays with a mean lifetime of 2.0 x 10{sup -6} sec. Two types of cooling have been used in the past. One is stochastic cooling where an electrode is used to detect the positions of the particles and send a signal to another position across the ring. Through successive applications of this technique, the phase space is ultimately greatly reduced and beams can be made to collide with a useful event rate. The second type of cooling is electron cooling. Here protons and electrons are made to travel together for a short distance. Equipartition causes transfer of transverse energy of the protons to that of the electrons. Neither of these methods is fast enough to allow acceleration of a sufficient number of muons up to maximum energy before they decay. A new method known as ionization cooling has been proposed.[1] The muons are cooled by passing them through a container of liquid hydrogen. The energy loss reduces both transverse and longitudinal momentum. The longitudinal momentum is restored with RF cavities. The net result is to maintain the longitudinal momentum while cooling the transverse momentum. To minimize the total travel distance of the muons the liquid hydrogen is placed inside the focusing solenoids. The question arises as to whether the presence of the solenoids influences the phase space occupied by the muons. After the muon scatters it has transverse momentum. In a constant longitudinal magnetic field the trajectory wraps around the field lines and coincides in momentum and position with a particle which scatters one cycle later. Here we calculate the change in emittance for both a drift space and a solenoid. We find that the presence of the solenoid does

  13. Hollow Plasma in a Solenoid

    SciTech Connect

    Anders, Andre; Kauffeldt, Marina; Oks, Efim M.; Roy, Prabir K.

    2010-11-30

    A ring cathode for a pulsed, high-current, multi-spot cathodic arc discharge was placed inside a pulsed magnetic solenoid. Photography is used to evaluate the plasma distribution. The plasma appears hollow for cathode positions close the center of the solenoid, and it is guided closer to the axis when the cathode is away from the center.

  14. Numerical analyses of trapped field magnet and stable levitation region of HTSC

    SciTech Connect

    Tsuchimoto, M.; Kojima, T.; Waki, H.; Honma, T.

    1995-05-01

    Stable levitation with a permanent magnet and a bulk high {Tc} superconductor (HTSC) is examined numerically by using the critical state model and the frozen field model. Differences between a permanent magnet and a trapped field magnet are first discussed from property of levitation force. Stable levitation region of the HTSC on a ring magnet and on a solenoid coil are calculated with the numerical methods. Obtained results are discussed from difference of the magnetic field configuration.

  15. A Magnetic Paradox

    ERIC Educational Resources Information Center

    Arndt, Ebe

    2006-01-01

    Two recent articles in this journal described how an air core solenoid connected to an ac power source may restore the magnetization of a bar magnet with an alternating magnetic field (see Figs. 1 and 2). Although we are quite accustomed to using a constant magnetic field in an air core solenoid to remagnetize a ferromagnet, it is puzzling that we…

  16. Cosmological magnetic fields

    NASA Astrophysics Data System (ADS)

    Kunze, Kerstin E.

    2013-12-01

    Magnetic fields are observed on nearly all scales in the Universe, from stars and galaxies up to galaxy clusters and even beyond. The origin of cosmic magnetic fields is still an open question, however a large class of models puts its origin in the very early Universe. A magnetic dynamo amplifying an initial seed magnetic field could explain the present day strength of the galactic magnetic field. However, it is still an open problem how and when this initial magnetic field was created. Observations of the cosmic microwave background (CMB) provide a window to the early Universe and might therefore be able to tell us whether cosmic magnetic fields are of a primordial cosmological origin and at the same time constrain its parameters. We will give an overview of the observational evidence of large-scale magnetic fields, describe generation mechanisms of primordial magnetic fields and possible imprints in the CMB.

  17. Radiofrequency hydrogen ion source with permanent magnets providing axial magnetic field.

    PubMed

    Oikawa, Kohei; Saito, Yuta; Komizunai, Shota; Takahashi, Kazunori; Ando, Akira

    2014-02-01

    Uniform axial magnetic field of about 70 G is applied to a radiofrequency (rf) hydrogen ion source by arrays of permanent magnets. The plasma density and electron temperature downstream of the source and near the magnetic filter are compared with those in the previously described ion source, where the axial field has been applied by two solenoids. The source is operated at ∼350 kHz and above 10 kW rf power with a field-effect-transistor-based invertor power supply in 1.5 Pa hydrogen. The results show that the plasma density of ∼10(19) m(-3) near the source exit and ∼10(18) m(-3) near the magnetic filter can be obtained, which are higher than those with the solenoids.

  18. Radiofrequency hydrogen ion source with permanent magnets providing axial magnetic field

    SciTech Connect

    Oikawa, Kohei Saito, Yuta; Komizunai, Shota; Takahashi, Kazunori; Ando, Akira

    2014-02-15

    Uniform axial magnetic field of about 70 G is applied to a radiofrequency (rf) hydrogen ion source by arrays of permanent magnets. The plasma density and electron temperature downstream of the source and near the magnetic filter are compared with those in the previously described ion source, where the axial field has been applied by two solenoids. The source is operated at ∼350 kHz and above 10 kW rf power with a field-effect-transistor-based invertor power supply in 1.5 Pa hydrogen. The results show that the plasma density of ∼10{sup 19} m{sup −3} near the source exit and ∼10{sup 18} m{sup −3} near the magnetic filter can be obtained, which are higher than those with the solenoids.

  19. Applications of a superconducting solenoidal separator in the experimental investigation of nuclear reactions

    NASA Astrophysics Data System (ADS)

    Hinde, D. J.; Carter, I. P.; Dasgupta, M.; Simpson, E. C.; Cook, K. J.; Kalkal, Sunil; Luong, D. H.; Williams, E.

    2017-01-01

    This paper describes applications of a novel superconducting solenoidal separator, with magnetic fields up to 8 Tesla, for studies of nuclear reactions using the Heavy Ion Accelerator Facility at the Australian National University.

  20. Progress on the Design and Fabircation of the MICE SpectrometerSolenoids

    SciTech Connect

    Virostek, S.P.; Green, M.A.; Lia, D.; Sizman, M.S.

    2007-06-20

    The Muon Ionization Cooling Experiment (MICE) willdemonstrate ionization cooling in a short section of a realistic coolingchannel using a muon beam at Rutherford Appleton Laboratory (RAL) in theUK. A five-coil, superconducting spectrometer solenoid magnet at each endof the cooling channel will provide a 4 T uniform field region for thescintillating fiber tracker within the magnet bore tubes. The trackermodules are used to measure the muon beam emittance as it enters andexits the cooling channel. The cold mass for the 400 mm warm bore magnetconsists of two sections: a three-coil spectrometer magnet and a two-coilmatching section that matches the uniform field of the solenoid into theMICE cooling channel. The spectrometer solenoid detailed designandanalysis has been completed, and the fabrication of the magnets is wellunder way. The primary features of the spectrometer solenoid magnet andmechanical designs are presented along with a summary of key fabricationissues and photos of the construction.

  1. Changes made on a 2.7-m long superconducting solenoid magnet cryogenic system that allowed the magnet to be kept cold using 4 K pulse tube coolers

    SciTech Connect

    Green, M. A.; Pan, H.; Preece, R. M.

    2014-01-29

    Two 2.7-m long solenoid magnets with a cold mass of 1400 kg were fabricated in between 2007 and 2010. The magnet cryostat outside diameter is ∼1.4 meters and the cryostat length is ∼2.73 meters. The magnet warm bore is 0.4 meters. The magnet was designed to be cooled using three 1.5 W two-stage coolers. In both magnets, three coolers could not keep the cryostat filled with liquid helium. The temperatures of the shield and the tops of the HTS leads were too warm. A 140 W single stage cooler was added to magnet 2 to cool the HTS leads, the shield and the cold mass support intercepts. When the magnet 2 was retested in 2010, the net cooling at 4.2 K was −1.5 W with first-stage temperatures of the four coolers at ∼42 K. The tops of the HTS leads were <50 K, but the shield and cold mass support intercepts remained too warm. The solenoid cryostat and shield were modified during 2011 and 2012 to reduce the 4.2 K heat load and increase the cooling. This magnet was tested in 2012, with five 1.5 W two-stage coolers and the single stage cooler. The changes made in the magnet are described in this report. As a result of the cryostat and shield changes, and adding 3.0 W of cooling at 4.2 K, the net 4.2 K cooling changed from −1.6 W to +5.0 W. About half of the change in net cooling to this magnet was due changes that reduced the shield temperature. This report demonstrates the importance of running the shield cold (∼40 K) and reducing the heat loads from all sources on both the shield and the cold mass.

  2. Analysis of transverse RMS emittance growth of a beam induced by spherical and chromatic aberration in a solenoidal field

    NASA Astrophysics Data System (ADS)

    Dash, Radhakanta; Nayak, Biswaranjan; Sharma, Archana; Mittal, Kailash C.

    2016-01-01

    In a medium energy beam transport line transverse rms emittance growth associated with spherical aberration is analysed. An analytical expression is derived for beam optics in a solenoid field considering terms up to the third order in the radial displacement. Two important phenomena: effect of spherical aberrations in axial-symmetric focusing lens and influence of nonlinear space charge forces on beam emittance growth are discussed for different beam distributions. In the second part nonlinear effect associated with chromatic aberration that describes the growth of emittance and distortion of phase space area is discussed.

  3. Photospheric magnetic fields

    NASA Technical Reports Server (NTRS)

    Howard, R.

    1972-01-01

    Knowledge on the nature of magnetic fields on the solar surface is reviewed. At least a large part of the magnetic flux in the solar surface is confined to small bundles of lines of force within which the field strength is of the order of 500 gauss. Magnetic fields are closely associated with all types of solar activity. Magnetic flux appears at the surface at the clearly defined birth or regeneration of activity of an active region. As the region ages, the magnetic flux migrates to form large-scale patterns and the polar fields. Some manifestations of the large-scale distribution are discussed.

  4. 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.

  5. Fabrication, Testing and Modeling of the MICE Superconducting Spectrometer Solenoids

    SciTech Connect

    Virostek, S.P.; Green, M.A.; Trillaud, F.; Zisman, M.S.

    2010-05-16

    The Muon Ionization Cooling Experiment (MICE), an international collaboration sited at Rutherford Appleton Laboratory in the UK, will demonstrate ionization cooling in a section of realistic cooling channel using a muon beam. A five-coil superconducting spectrometer solenoid magnet will provide a 4 tesla uniform field region at each end of the cooling channel. Scintillating fiber trackers within the 400 mm diameter magnet bore tubes measure the emittance of the beam as it enters and exits the cooling channel. Each of the identical 3-meter long magnets incorporates a three-coil spectrometer magnet section and a two-coil section to match the solenoid uniform field into the other magnets of the MICE cooling channel. The cold mass, radiation shield and leads are currently kept cold by means of three two-stage cryocoolers and one single-stage cryocooler. Liquid helium within the cold mass is maintained by means of a re-condensation technique. After incorporating several design changes to improve the magnet cooling and reliability, the fabrication and acceptance testing of the spectrometer solenoids have proceeded. The key features of the spectrometer solenoid magnets, the development of a thermal model, the results of the recently completed tests, and the current status of the project are presented.

  6. Organic magnetic field sensor

    DOEpatents

    McCamey, Dane; Boehme, Christoph

    2017-01-24

    An organic, spin-dependent magnetic field sensor (10) includes an active stack (12) having an organic material with a spin-dependence. The sensor (10) also includes a back electrical contact (14) electrically coupled to a back of the active stack (12) and a front electrical contact (16) electrically coupled to a front of the active stack (12). A magnetic field generator (18) is oriented so as to provide an oscillating magnetic field which penetrates the active stack (12).

  7. Test of microchannel plates in magnetic fields up to 4.5 T

    NASA Astrophysics Data System (ADS)

    Barnyakov, A. Yu; Barnyakov, M. Yu; Prisekin, V. G.; Karpov, S. V.; Katcin, A. A.

    2017-02-01

    Detectors based on microchannel plates (MCP) can provide high time resolution and are able to operate in high magnetic field. An experimental setup based on a superconductive solenoid with 120 mm bore was created in BINP. The influence of magnetic field up to 4.5 T on the MCP photomultiplier parameters was studied. Several types of photodetectors produced in Novosibirsk were tested. Results of time resolution measurements, dependencies of gain and photon detection efficiency on magnetic field are presented.

  8. Magnetic field generator

    DOEpatents

    Krienin, Frank

    1990-01-01

    A magnetic field generating device provides a useful magnetic field within a specific retgion, while keeping nearby surrounding regions virtually field free. By placing an appropriate current density along a flux line of the source, the stray field effects of the generator may be contained. One current carrying structure may support a truncated cosine distribution, and it may be surrounded by a current structure which follows a flux line that would occur in a full coaxial double cosine distribution. Strong magnetic fields may be generated and contained using superconducting cables to approximate required current surfaces.

  9. SU-E-J-233: A Facility for Radiobiological Experiments in a Large Magnetic Field

    SciTech Connect

    Carlone, M; Heaton, R; Keller, H; Wouters, B; Jaffray, D

    2014-06-01

    Purpose: There is considerable interest in developing medical linear accelerators with integrated image guidance by MRI. Less work has been done on the fundamental biology of cell survival in the presence of a strong magnetic field. The purpose of this work is to describe an experimental system capable of measuring cell survival response in the types of MRI-linac systems currently under development. Methods: We have integrated a cobalt irradiator with a solenoid magnet. The solenoid magnet has inner diameter of 10 cm. To enable measurement of the biological effects as a function of depth, we are utilizing the sliced gel technique, in which cells are embedded and fixed within a gelatin matrix. Irradiated cells at defined positions (sub mm resolution) can subsequently be recovered and assessed for cell survival or other biological effects. Results: The magnetic field profile in the solenoid has a peak magnetic field 36 cm below the top edge of the magnet bore and can be placed at and SAD of 100 cm. At a solenoid current of 35 A, the peak magnetic field is 0.25 T. The dose rate of the cobalt irradiator is 16 cGy/min at 100 cm SAD. EBT3 film was used to demonstrate the system functionality. It was irradiated at 1 cm depth at 100 cm SSD with a 4×4 field to 1.5 Gy in a 0.25 T magnetic field. The dose profile was similar between this film and the control exposure without magnetic field. Conclusion: Integrating a cobalt irradiator with a high field magnet is demonstrated. The magnetic field at the cobalt defining head was minimal and did not interfere with the functioning of this unit. Cell survival experiments can be reproduced exactly in the presence or absence of a magnetic field since a resistive magnet is used.

  10. Open Cavity Solutions to the rf in Magnetic Field Problem

    SciTech Connect

    Palmer, Robert B.; Berg, J. Scott; Fernow, Richard C.; Gallardo, Juan C.; Kirk, Harold G.

    2008-02-21

    It has been observed that breakdown in an 805 MHz pill-box cavity occurs at much lower gradients as an external axial magnetic field is increased. This effect was not observed with on open iris cavity. It is proposed that this effect depends on the relative angles of the magnetic and maximum electric fields: parallel in the pill-box case; at an angle in the open iris case. If so, using an open iris structure with solenoid coils in the irises should perform even better. A lattice, using this principle, is presented, for use in 6D cooling for a Muon Collider. Experimental layouts to test this principle are proposed.

  11. OPEN CAVITY SOLUTIONS TO THE RF IN MAGNETIC FIELD PROBLEM.

    SciTech Connect

    PALMER,R.B.; BERG, J.S.; FERNOW, R.C.; GALLARDO, J.C.; KIRK, H.G.

    2007-08-06

    It has been observed [1] that breakdown in an 805 MHz pill-box cavity occurs at much lower gradients as an external axial magnetic field is increased. This effect was not observed with on open iris cavity. It is proposed that this effect depends on the relative angles of the magnetic and maximum electric fields: parallel in the pill-box case; at an angle in the open iris case. If so, using an open iris structure with solenoid coils in the irises should perform even better. A lattice, using this principle, is presented, for use in 6D cooling for a Muon Collider. Experimental layouts to test this principle are proposed.

  12. Superconducting Solenoid for Superfast THz Spectroscopy

    NASA Astrophysics Data System (ADS)

    Bragin, A. V.; Khrushchev, S. V.; Kubarev, V. V.; Mezencev, N. A.; Tsukanov, V. M.; Sozinov, G. I.; Shkaruba, V. A.

    This project is related to new spectroscopy method in little-developed THz range. The method is founded on using of a free electron laser (NovoFEL) with high spectral power radiation which can be smoothly tuned in desirable range of spectrum. The objects of research of this method are fast processes in physics, chemical and biological reactions. Uniform magnetic field of 6 T value in the research area can considerably increase possibilities of this method. The magnetic field will modulate radiation of free molecules induction on characteristic frequencies of the Zeeman splitting that gives more possibilities of identification of molecules having even weak magnetic momentum. Moreover, the use of magnetic field allows essentially increase sensitivity of this method due to almost complete separation of weak measuring signals from powerful radiation of the laser. A superconducting solenoid was developed for this method. Its design and peculiarities are described in this paper.

  13. Magnetosheath magnetic field variability

    NASA Technical Reports Server (NTRS)

    Sibeck, D. G.

    1994-01-01

    A case study using simulations IRM and CCE observations demonstrates that transient magnetospheric events correspond to pressure pulses in the magnetosheath, inward bow shock motion, and magnetopause compression. Statistical surveys indicate that the magnetosheath magnetic field orientation rarely remains constant during periods of magnetopause and bow shock motion (both characterized by periods of 1 to 10 min). There is no tendency for bow shock motion to occur for southward interplanetary magnetic field (IMF) orientations.

  14. Magnetic field dosimeter development

    SciTech Connect

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

    1980-09-01

    In recent years there has been increased concern over potential health hazards related to exposure of personnel to magnetic fields. If exposure standards are to be established, then a means for measuring magnetic field dose must be available. To meet this need, the Department of Energy has funded development of prototype dosimeters at the Battelle Pacific Northwest Laboratory. This manual reviews the principle of operation of the dosimeter and also contains step-by-step instructions for its operation.

  15. Standing Helicon Wave Induced by a Rapidly Bent Magnetic Field in Plasmas.

    PubMed

    Takahashi, Kazunori; Takayama, Sho; Komuro, Atsushi; Ando, Akira

    2016-04-01

    An electron energy probability function and a rf magnetic field are measured in a rf hydrogen helicon source, where axial and transverse static magnetic fields are applied to the source by solenoids and to the diffusion chamber by filter magnets, respectively. It is demonstrated that the helicon wave is reflected by the rapidly bent magnetic field and the resultant standing wave heats the electrons between the source and the magnetic filter, while the electron cooling effect by the magnetic filter is maintained. It is interpreted that the standing wave is generated by the presence of a spatially localized change of a refractive index.

  16. Three dimensional multilayer solenoid microcoils inside silica glass

    NASA Astrophysics Data System (ADS)

    Meng, Xiangwei; Yang, Qing; Chen, Feng; Shan, Chao; Liu, Keyin; Li, Yanyang; Bian, Hao; Si, Jinhai; Hou, Xun

    2016-01-01

    Three dimensional (3D) solenoid microcoils could generate uniform magnetic field. Multilayer solenoid microcoils are highly pursued for strong magnetic field and high inductance in advanced magnetic microsystems. However, the fabrication of the 3D multilayer solenoid microcoils is still a challenging task. In this paper, 3D multilayer solenoid microcoils with uniform diameters and high aspect ratio were fabricated in silica glass. An alloy (Bi/In/Sn/Pb) with high melting point was chosen as the conductive metal to overcome the limitation of working temperature and improve the electrical property. The inductance of the three layers microcoils was measured, and the value is 77.71 nH at 100 kHz and 17.39 nH at 120 MHz. The quality factor was calculated, and it has a value of 5.02 at 120 MHz. This approach shows an improvement method to achieve complex 3D metal microstructures and electronic components, which could be widely integrated in advanced magnetic microsystems.

  17. Mu2e Transport Solenoid Cold-Mass Alignment Issues

    DOE PAGES

    Lopes, M.; Ambrosio, G.; Badgley, K.; ...

    2017-01-05

    The Muon-to-electron conversion experiment (Mu2e) at Fermilab is designed to explore charged lepton flavor violation. It is composed of three large superconducting solenoids: the Production Solenoid (PS), the Transport Solenoid (TS) and the Detector Solenoid (DS). The TS is formed by two magnets: TS upstream (TSu) and downstream (TSd). Each has its own cryostat and power supply. Tolerance sensitivity studies of the position and angular alignment of each coil in this magnet system were performed in the past with the objective to demonstrate that the magnet design meets all the field requirements. Furthermore, the alignment of the cold-masses is criticalmore » to maximize the transmission of muons and to avoid possible backgrounds that would reduce the sensitivity of the experiment. Each TS magnet cold-mass can be individually aligned. Here, we discuss implications of the alignment of the TS cold-masses in terms of the displacement of the magnetic center. Consideration of the practical mechanical limits are also presented.« less

  18. Solar Wind Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Smith, E. J.

    1995-01-01

    The magnetic fields originate as coronal fields that are converted into space by the supersonic, infinitely conducting, solar wind. On average, the sun's rotation causes the field to wind up and form an Archimedes Spiral. However, the field direction changes almost continuously on a variety of scales and the irregular nature of these changes is often interpreted as evidence that the solar wind flow is turbulent.

  19. Nuclear Spin Maser at Highly Stabilized Low Magnetic Field and Search for Atomic EDM

    SciTech Connect

    Yoshimi, A.; Asahi, K.; Inoue, T.; Uchida, M.; Hatakeyama, N.; Tsuchiya, M.; Kagami, S.

    2009-08-04

    A nuclear spin maser is operated at a low static field through an active feedback scheme based on an optical nuclear spin detection and succeeding spin control by a transverse field application. The frequency stability of this optical-coupling spin maser is improved by installation of a low-noise current source for a solenoid magnet producing a static magnetic field in the maser operation. Experimental devices for application of the maser to EDM experiment are being developed.

  20. Molecules in Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Berdyugina, Svetlana

    2015-08-01

    Molecules probe cool matter in the Universe and various astrophysical objects. Their ability to sense magnetic fields provides new insights into magnetic properties of these objects. During the past fifteen years we have carried out a theoretical study of molecular magnetic effects such as the Zeeman, Paschen-Back and Hanle effects and their applications for inferring magnetic structures and spatial inhomogeneities on the Sun, cool stars, brown dwarfs, and exoplanets from molecular spectro-polarimetry (e.g., Berdyugina 2011). Here, we present an overview of this study and compare our theoretical predictions with recent laboratory measurements of magnetic properties of some molecules. We present also a new web-based tool to compute molecular magnetic effects and polarized spectra which is supported by the ERC Advanced Grant HotMol.

  1. Focusing solenoids for the MICE cooling channel

    SciTech Connect

    Green, M.A.; Baynham, E.; Barr, G.; Lau, W.; Rochford, J.H.; Yang, S.

    2003-09-15

    This report describes a design for focusing solenoids for the low beta sections for the proposed Muon Ionization Cooling Experiment (MICE). There are three focusing solenoid pairs that will be around the muon absorbers for MICE. The two solenoid coils have an inside diameter of 510 mm, a length of 180 mm, and a thickness of 100 mm. A distance of 260 mm separates the two coils in the pair. The coils are designed to operate at opposite polarity, in order to create a gradient field in the low beta sections of the MICE cooling channel. As result, the force pushing the coil pair apart approaches 270 metric tons when the coils operate close to the short sample current for the superconductor. The forces between the coils will be carried by a support structure that is both on the inside and the outside the coils. During some modes of operation for MICE, the coils may operate at the same polarity, which means that the force between the coils pushes them together. The focusing magnet must be designed for both modes of operation. This support structure for the coils will be part of the focusing magnet quench protection system.

  2. Magnetic Field Solver

    NASA Technical Reports Server (NTRS)

    Ilin, Andrew V.

    2006-01-01

    The Magnetic Field Solver computer program calculates the magnetic field generated by a group of collinear, cylindrical axisymmetric electromagnet coils. Given the current flowing in, and the number of turns, axial position, and axial and radial dimensions of each coil, the program calculates matrix coefficients for a finite-difference system of equations that approximates a two-dimensional partial differential equation for the magnetic potential contributed by the coil. The program iteratively solves these finite-difference equations by use of the modified incomplete Cholesky preconditioned-conjugate-gradient method. The total magnetic potential as a function of axial (z) and radial (r) position is then calculated as a sum of the magnetic potentials of the individual coils, using a high-accuracy interpolation scheme. Then the r and z components of the magnetic field as functions of r and z are calculated from the total magnetic potential by use of a high-accuracy finite-difference scheme. Notably, for the finite-difference calculations, the program generates nonuniform two-dimensional computational meshes from nonuniform one-dimensional meshes. Each mesh is generated in such a way as to minimize the numerical error for a benchmark one-dimensional magnetostatic problem.

  3. Ultra-high field magnets for whole-body MRI

    NASA Astrophysics Data System (ADS)

    Warner, Rory

    2016-09-01

    For whole-body MRI, an ultra-high field (UHF) magnet is currently defined as a system operating at 7 T or above. Over 70 UHF magnets have been built, all with the same technical approach originally developed by Magnex Scientific Ltd. The preferred coil configuration is a compensated solenoid. In this case, the majority of the field is generated by a simple long solenoid that stretches the entire length of the magnet. Additional coils are wound on a separate former outside the main windings with the purpose of balancing the homogeneity. Most of the magnets currently in operation are passively shielded systems where the magnet is surrounded by a steel box of 200-870 tonnes of carbon steel. More recently actively shielded magnets have been built for operation at 7 T; in this case the stray field is controlled by with reverse turns wound on a separate former outside the primary coils. Protection against quench damage is much more complex with an actively shielded magnet design due to the requirement to prevent the stray field from increasing during a quench. In the case of the 7 T 900 magnet this controlled by combining some of the screening coils into each section of the protection circuit. Correction of the field variations caused by manufacturing tolerances and environmental effects are made with a combination of superconducting shims and passive shims. Modern UHF magnets operate in zero boil-off mode with the use of cryocoolers with cooling capacity at 4.2 K. Although there are no cryogen costs associated with normal operation UHF magnets require a significant volume (10 000-20 000 l) of liquid helium for the cool-down. Liquid helium is expensive therefore new methods of cool-down using high-power cryocoolers are being implemented to reduce the requirement.

  4. Magnetic fields at uranus.

    PubMed

    Ness, N F; Acuña, M H; Behannon, K W; Burlaga, L F; Connerney, J E; Lepping, R P; Neubauer, F M

    1986-07-04

    The magnetic field experiment on the Voyager 2 spacecraft revealed a strong planetary magnetic field of Uranus and an associated magnetosphere and fully developed bipolar masnetic tail. The detached bow shock wave in the solar wind supersonic flow was observed upstream at 23.7 Uranus radii (1 R(U) = 25,600 km) and the magnetopause boundary at 18.0 R(U), near the planet-sun line. A miaximum magnetic field of 413 nanotesla was observed at 4.19 R(U ), just before closest approach. Initial analyses reveal that the planetary magnetic field is well represented by that of a dipole offset from the center of the planet by 0.3 R(U). The angle between Uranus' angular momentum vector and the dipole moment vector has the surprisingly large value of 60 degrees. Thus, in an astrophysical context, the field of Uranus may be described as that of an oblique rotator. The dipole moment of 0.23 gauss R(3)(U), combined with the large spatial offset, leads to minimum and maximum magnetic fields on the surface of the planet of approximately 0.1 and 1.1 gauss, respectively. The rotation period of the magnetic field and hence that of the interior of the planet is estimated to be 17.29+/- 0.10 hours; the magnetotail rotates about the planet-sun line with the same period. Thelarge offset and tilt lead to auroral zones far from the planetary rotation axis poles. The rings and the moons are embedded deep within the magnetosphere, and, because of the large dipole tilt, they will have a profound and diurnally varying influence as absorbers of the trapped radiation belt particles.

  5. Statistically-Averaged Rate Equations Obtained in Kinetic Description of Intense Nonneutral Beam Propagation Through a Periodic Solenoidal Focusing Field

    NASA Astrophysics Data System (ADS)

    Lee, W. Wei-Li; Davidson, Ronald C.; Stoltz, Peter

    1997-11-01

    This paper presents a detailed formulation and analysis of the rate equations for statistically-averaged quantities for an intense nonneutral beam propagating through a periodic solenoidal focusing field. B^sol(x) = B_z(z)hatez - (1/2)B'_z(z)(xhatex + yhate_y), where B_z(z+S) = B_z(z), and S = const. is the axial periodicity length. The anaysis assumes a thin beam with characteristic beam radius rb << S, and is based on the nonlinear Vlasov-Maxwell equations. Particularly important in experimental applications and in numerical simulations schemes, such as the nonlinear δ f- scheme,(Q. Qian, W. Lee, and R. Davidson, Phys. Plasmas 4), 1915 (1997). is an understanding of the self-consistent nonlinear evolution of various quantities averaged over the distribution of beam particles f_b(x,p,t). Self-consistent rate equations are derived for the nonlinear evolution of the mean-square beam radius , mean kinetic energy (1/2), field energy ɛ_F(z), unnormalized beam emittance ɛ(z), center of mass motion, etc., and the nonlinear beam dynamics is analysed over a wide range of system parameters.

  6. Mercury's Magnetic Field

    NASA Astrophysics Data System (ADS)

    Johnson, C. L.

    2014-12-01

    Mercury is the only inner solar system body other than Earth to possess an active core dynamo-driven magnetic field and the only planet with a small, highly dynamic magnetosphere. Measurements made by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft have provided a wealth of data on Mercury's magnetic field environment. Mercury's weak magnetic field was discovered 40 years ago by the Mariner 10 spacecraft, but its large-scale geometry, strength and origin could not be definitively established. MESSENGER data have shown that the field is dynamo-generated and can be described as an offset axisymmetric dipole field (hereafter OAD): the magnetic equator lies ~0.2 RM (RM = 2440 km) north of the geographic equator and the dipole moment is 2.8 x1019 Am2 (~0.03% that of Earth's). The weak internal field and the high, but variable, solar wind ram pressure drive vigorous magnetospheric dynamics and result in an average distance from the planet center to the sub-solar magnetopause of only 1.42 RM. Magnetospheric models developed with MESSENGER data have allowed re-analysis of the Mariner 10 observations, establishing that there has been no measureable secular variation in the internal field over 40 years. Together with spatial power spectra for the OAD, this provides critical constraints for viable dynamo models. Time-varying magnetopause fields induce secondary core fields, the magnitudes of which confirm the core radius estimated from MESSENGER gravity and Earth-based radar data. After accounting for large-scale magnetospheric fields, residual signatures are dominated by additional external fields that are organized in the local time frame and that vary with magnetospheric activity. Birkeland currents have been identified, which likely close in the planetary interior at depths below the base of the crust. Near-periapsis magnetic field measurements at altitudes greater than 200 km have tantalizing hints of crustal fields, but crustal

  7. Modeling of particles orientation in magnetic field in drying magnetic coatings

    NASA Astrophysics Data System (ADS)

    Potanin, Andrei A.; Reynolds, George; J. Hirko, Ronald

    2000-03-01

    Filament coating is studied as a model of magnetic tape manufacturing. Freshly coated filament is driven through a solenoid magnet which orients particles. After drying the coated filament, its squareness is measured as a function of the magnet position, field and the filament speed during coating. Production and model mixes are tested, which differ in dispersion quality and drying rate. A mean-field model is used to describe orientation of particles in the coating. The model fits experiments with two parameters: particles mobility and a mean-field interaction coefficient. Well dispersed kneaded mix has higher mobility and weaker interactions than non-kneaded mixes. The model well agrees with the data for squareness decay with magnet separation from the mix deposition point, thereby providing a theoretical tool for finding proper magnet position on the production coating lines.

  8. Precise mapping of the magnetic field in the CMS barrel yoke using cosmic rays

    SciTech Connect

    Chatrchyan, S.; et al.,

    2010-03-01

    The CMS detector is designed around a large 4 T superconducting solenoid, enclosed in a 12000-tonne steel return yoke. A detailed map of the magnetic field is required for the accurate simulation and reconstruction of physics events in the CMS detector, not only in the inner tracking region inside the solenoid but also in the large and complex structure of the steel yoke, which is instrumented with muon chambers. Using a large sample of cosmic muon events collected by CMS in 2008, the field in the steel of the barrel yoke has been determined with a precision of 3 to 8% depending on the location.

  9. Analytical studies of advanced high-field designs: 20-tesla large-bore superconducting magnets

    SciTech Connect

    Hoard, R.W.; Cornish, D.N.; Scanlan, R.M.; Zbasnik, J.P.; Leber, R.L.; Hickman, R.B.; Lee, J.D.

    1983-09-30

    Several emerging technologies have been combined in a conceptual design study demonstrating the feasibility of producing ultrahigh magnetic fields from large-bore superconducting solenoid magnets. Several designs have been produced that approach peak fields of 20-T in 2.0-m diameter inner bores. The analytical expressions comprising the main features of CONDUCTOR and ADVMAGNET, the two computer programs used in the design of these advanced magnets, are also discussed. These magnets and design techniques will make a paramount contribution to the national mirror-fusion endeavor and to the newly emerging field of nuclear magnetic resonance (NMR) whole-body scanners.

  10. Magnetic fields from inflation?

    SciTech Connect

    Demozzi, Vittoria; Mukhanov, Viatcheslav; Rubinstein, Hector E-mail: viatcheslav.mukhanov@physik.uni-muenchen.de

    2009-08-01

    We consider the possibility of generation of the primordial magnetic field on inflation and show that the effect of the back reaction of this field can be very important. Assuming that the back reaction does not spoil inflation we find a rather strong restriction on the amplitude of the primordial field which could be generated on inflation. Namely, this amplitude recalculated to the present epoch cannot exceed 10{sup −32}G in Mpc scales. This field seems to be too small to be amplified to the observable values by a possible dynamo mechanism.

  11. Simulation of RF Cavity Dark Current In Presence of Helical Magnetic Field

    SciTech Connect

    Romanov, Gennady; Kashikhin, Vladimir; /Fermilab

    2012-05-01

    In order to produce muon beam of high enough quality to be used for a Muon Collider, its large phase space must be cooled several orders of magnitude. This task can be accomplished by ionization cooling. Ionization cooling consists of passing a high-emittance muon beam alternately through regions of low Z material, such as liquid hydrogen, and very high accelerating RF cavities within a multi-Tesla solenoidal focusing channel. But first high power tests of RF cavity with beryllium windows in solenoidal magnetic field showed a dramatic drop in accelerating gradient due to RF breakdowns. It has been concluded that external magnetic fields parallel to RF electric field significantly modifies the performance of RF cavities. However, magnetic field in Helical Cooling Channel has a strong dipole component in addition to solenoidal one. The dipole component essentially changes electron motion in a cavity compare to pure solenoidal case, making dark current less focused at field emission sites. The simulation of dark current dynamic in HCC performed with CST Studio Suit is presented in this paper.

  12. Simulation of RF Cavity Dark Current in Presence of Helical Magnetic Field

    SciTech Connect

    Romanov, Gennady; Kashikhin, Vladimir; /Unlisted

    2010-09-01

    In order to produce muon beam of high enough quality to be used for a Muon Collider, its large phase space must be cooled several orders of magnitude. This task can be accomplished by ionization cooling. Ionization cooling consists of passing a high-emittance muon beam alternately through regions of low Z material, such as liquid hydrogen, and very high accelerating RF cavities within a multi-Tesla solenoidal focusing channel. But first high power tests of RF cavity with beryllium windows in solenoidal magnetic field showed a dramatic drop in accelerating gradient due to RF breakdowns. It has been concluded that external magnetic fields parallel to RF electric field significantly modifies the performance of RF cavities. However, magnetic field in Helical Cooling Channel has a strong dipole component in addition to solenoidal one. The dipole component essentially changes electron motion in a cavity compare to pure solenoidal case, making dark current less focused at field emission sites. The simulation of dark current dynamic in HCC performed with CST Studio Suit is presented in this paper.

  13. Dense Metal Plasma in a Solenoid for Ion Beam Neutralization

    SciTech Connect

    Anders, Andre; Kauffeldt, Marina; Oks, Efim M.; Roy, Prabir K.

    2010-10-30

    Space-charge neutralization is required to compress and focus a pulsed, high-current ion beam on a target for warm dense matter physics or heavy ion fusion experiments. We described approaches to produce dense plasma in and near the final focusing solenoid through which the ion beam travels, thereby providing an opportunity for the beam to acquire the necessary space-charge compensating electrons. Among the options are plasma injection from pulsed vacuum arc sources located outside the solenoid, and using a high current (> 4 kA) pulsed vacuum arc plasma from a ring cathode near the edge of the solenoid. The plasma distribution is characterized by photographic means, by an array of movable Langmuir probes, by a small single probe, and by evaluating Stark broadening of the Balmer H beta spectral line. In the main approach described here, the plasma is produced at several cathode spots distributed azimuthally on the ring cathode. It is shown that the plasma is essentially hollow, as determined by the structure of the magnetic field, though the plasma density exceeds 1014 cm-3 in practically all zones of the solenoid volume if the ring electrode is placed a few centimeters off the center of the solenoid. The plasma is non-uniform and fluctuating, however, since its density exceeds the ion beam density it is believed that this approach could provide a practical solution to the space charge neutralization challenge.

  14. High field superconducting magnets

    NASA Technical Reports Server (NTRS)

    Hait, Thomas P. (Inventor); Shirron, Peter J. (Inventor)

    2011-01-01

    A superconducting magnet includes an insulating layer disposed about the surface of a mandrel; a superconducting wire wound in adjacent turns about the mandrel to form the superconducting magnet, wherein the superconducting wire is in thermal communication with the mandrel, and the superconducting magnet has a field-to-current ratio equal to or greater than 1.1 Tesla per Ampere; a thermally conductive potting material configured to fill interstices between the adjacent turns, wherein the thermally conductive potting material and the superconducting wire provide a path for dissipation of heat; and a voltage limiting device disposed across each end of the superconducting wire, wherein the voltage limiting device is configured to prevent a voltage excursion across the superconducting wire during quench of the superconducting magnet.

  15. The interplanetary magnetic field

    NASA Technical Reports Server (NTRS)

    Davis, L., Jr.

    1972-01-01

    Large-scale properties of the interplanetary magnetic field as determined by the solar wind velocity structure are examined. The various ways in which magnetic fields affect phenomena in the solar wind are summarized. The dominant role of high and low velocity solar wind streams that persist, with fluctuations and evolution, for weeks or months is emphasized. It is suggested that for most purposes the sector structure is better identified with the stream structure than with the magnetic polarity and that the polarity does not necessarily change from one velocity sector to the next. Several mechanisms that might produce the stream structure are considered. The interaction of the high and low velocity streams is analyzed in a model that is steady state when viewed in a frame that corotates with the sun.

  16. Kinetic description of intense nonneutral beam propagation through a periodic solenoidal focusing field based on the nonlinear Vlasov-Maxwell equations

    SciTech Connect

    Davidson, R.C.; Chen, C.

    1997-08-01

    A kinetic description of intense nonneutral beam propagation through a periodic solenoidal focusing field B{sup sol}({rvec x}) is developed. The analysis is carried out for a thin beam with characteristic beam radius r{sub b} {much_lt} S, and directed axial momentum {gamma}{sub b}m{beta}{sub b}c (in the z-direction) large compared with the transverse momentum and axial momentum spread of the beam particles. Making use of the nonlinear Vlasov-Maxwell equations for general distribution function f{sub b}({rvec x},{rvec p},t) and self-consistent electrostatic field consistent with the thin-beam approximation, the kinetic model is used to investigate detailed beam equilibrium properties for a variety of distribution functions. Examples are presented both for the case of a uniform solenoidal focusing field B{sub z}(z) = B{sub 0} = const. and for the case of a periodic solenoidal focusing field B{sub z}(z + S) = B{sub z}(z). The nonlinear Vlasov-Maxwell equations are simplified in the thin-beam approximation, and an alternative Hamiltonian formulation is developed that is particularly well-suited to intense beam propagation in periodic focusing systems. Based on the present analysis, the Vlasov-Maxwell description of intense nonneutral beam propagation through a periodic solenoidal focusing field {rvec B}{sup sol}({rvec x}) is found to be remarkably tractable and rich in physics content. The Vlasov-Maxwell formalism developed here can be extended in a straightforward manner to investigate detailed stability behavior for perturbations about specific choices of beam equilibria.

  17. The UCLA Phi Factory detector, the integration of superconducting compensation solenoids and the final focus interaction region quadrupoles

    SciTech Connect

    Green, M.A. ); Cline, D.B. . Dept. of Physics)

    1992-06-01

    The proposed Phi Factory for the University of California at Los Angeles (UCLA) is a small 510 MeV electron-positron colliding beam storage ring with high luminosity (greater than 10{sup 32} CM{sup {minus}2} S{sup {minus}1}). In order to do high quality Phi physics, a particle detector system with a large solid angle (preferably greater than 98 percent ) is required. Particle detection and analysis will be done within a 0.5 tesla solenoidal magnetic field. The solenoidal field within the detector causes coupling between beam oscillations in the horizontal and vertical directions. Therefore, compensation solenoids are required to keep the circulating particle beams from seeing the effects of the field from the main detector solenoid. Since high luminosity and a large solid angle are required, the detectors and a pair of compensation solenoids must be integrated with the final focus quadrupoles within the detector straight section. This report describes the design of two tapered, 0.5 tesla, superconducting compensation solenoids which must go around six rare earth permanent final focus quadrupoles or six superconducting quadrupoles on either side of the beam collision point. A cryogenic cooling system for these two solenoids, which will be coupled with the cooling system for the primary detector solenoid, is also described.

  18. Thermal design of the Mu2e detector solenoid

    SciTech Connect

    Dhanaraj, N.; Wands, R.; Buehler, M.; Feher, S.; Page, T.; Peterson, T.; Schmitt, R.

    2014-12-18

    The reference design for a superconducting detector solenoid (DS) for the Mu2e experiment has been completed. In this study, the main functions of the DS are to provide a graded field in the region of the stopping target, which ranges from 2 to 1 T and a uniform precision magnetic field of 1 T in a volume large enough to house a tracker downstream of the stopping target. The inner diameter of the magnet cryostat is 1.9 m and the length is 10.9 m. The gradient section of the magnet is about 4 m long and the spectrometer section with a uniform magnetic field is about 6 m long. The inner cryostat wall supports the stopping target, tracker, calorimeter and other equipment installed in the DS. This warm bore volume is under vacuum during operation. It is sealed on one end by the muon beam stop, while it is open on the other end where it interfaces with the Transport Solenoid. The operating temperature of the magnetic coil is 4.7 K and is indirectly cooled with helium flowing in a thermosiphon cooling scheme. This paper describes the thermal design of the solenoid, including the design aspects of the thermosiphon for the coil cooling, forced flow cooling of the thermal shields with 2 phase LN2 (Liquid Nitrogen) and the transient studies of the cool down of the cold mass as well.

  19. Thermal design of the Mu2e detector solenoid

    DOE PAGES

    Dhanaraj, N.; Wands, R.; Buehler, M.; ...

    2014-12-18

    The reference design for a superconducting detector solenoid (DS) for the Mu2e experiment has been completed. In this study, the main functions of the DS are to provide a graded field in the region of the stopping target, which ranges from 2 to 1 T and a uniform precision magnetic field of 1 T in a volume large enough to house a tracker downstream of the stopping target. The inner diameter of the magnet cryostat is 1.9 m and the length is 10.9 m. The gradient section of the magnet is about 4 m long and the spectrometer section withmore » a uniform magnetic field is about 6 m long. The inner cryostat wall supports the stopping target, tracker, calorimeter and other equipment installed in the DS. This warm bore volume is under vacuum during operation. It is sealed on one end by the muon beam stop, while it is open on the other end where it interfaces with the Transport Solenoid. The operating temperature of the magnetic coil is 4.7 K and is indirectly cooled with helium flowing in a thermosiphon cooling scheme. This paper describes the thermal design of the solenoid, including the design aspects of the thermosiphon for the coil cooling, forced flow cooling of the thermal shields with 2 phase LN2 (Liquid Nitrogen) and the transient studies of the cool down of the cold mass as well.« less

  20. Quench anaylsis of MICE spectrometer superconducting solenoid

    SciTech Connect

    Kashikhin, Vladimir; Bross, Alan; Prestemon, Soren; / /LBL, Berkeley

    2011-09-01

    MICE superconducting spectrometer solenoids fabrication and tests are in progress now. First tests of the Spectrometer Solenoid discovered some issues which could be related to the chosen passive quench protection system. Both solenoids do not have heaters and quench propagation relied on the 'quench back' effect, cold diodes, and shunt resistors. The solenoids have very large inductances and stored energy which is 100% dissipated in the cold mass during a quench. This makes their protection a challenging task. The paper presents the quench analysis of these solenoids based on 3D FEA solution of coupled transient electromagnetic and thermal problems. The simulations used the Vector Fields QUENCH code. It is shown that in some quench scenarios, the quench propagation is relatively slow and some areas can be overheated. They describe ways of improving the solenoids quench protection in order to reduce the risk of possible failure.

  1. Effect of the solenoid in various conditions of the laser ion source at Brookhaven National Laboratory.

    PubMed

    Ikeda, S; Kumaki, M; Kanesue, T; Okamura, M

    2016-02-01

    In the laser ion source (LIS) at the Brookhaven National Laboratory (BNL), a solenoid is used to guide the laser ablation plasma and modulate the extracted beam current. Many types of ion species are guided. In some cases, the plasma plume is injected into the solenoid away from the solenoidal axis. To investigate the effects of the solenoid on the beam extracted from the plasma that has different properties, the beam current was measured in the setup of the LIS at the BNL. The beam current of Li, Al, Si, Fe, and Au increased when the magnetic field was applied. For most of the species the peak current and the total charge within a single beam pulse increased around 10 times with a magnetic field less than 100 G. In addition, for some species the rate of increase of the peak currents became smaller when the magnetic flux densities were larger than certain values depending on the species. In this case, the current waveforms were distorted. At the same magnetic field value, the field was more effective on lighter species than on heavier ones. When plasma was injected offset from the axis of the solenoid, peak current and total charge became half of those without offset. The experimental data are useful for the operation of the LIS at the BNL.

  2. Effect of the solenoid in various conditions of the laser ion source at Brookhaven National Laboratory

    NASA Astrophysics Data System (ADS)

    Ikeda, S.; Kumaki, M.; Kanesue, T.; Okamura, M.

    2016-02-01

    In the laser ion source (LIS) at the Brookhaven National Laboratory (BNL), a solenoid is used to guide the laser ablation plasma and modulate the extracted beam current. Many types of ion species are guided. In some cases, the plasma plume is injected into the solenoid away from the solenoidal axis. To investigate the effects of the solenoid on the beam extracted from the plasma that has different properties, the beam current was measured in the setup of the LIS at the BNL. The beam current of Li, Al, Si, Fe, and Au increased when the magnetic field was applied. For most of the species the peak current and the total charge within a single beam pulse increased around 10 times with a magnetic field less than 100 G. In addition, for some species the rate of increase of the peak currents became smaller when the magnetic flux densities were larger than certain values depending on the species. In this case, the current waveforms were distorted. At the same magnetic field value, the field was more effective on lighter species than on heavier ones. When plasma was injected offset from the axis of the solenoid, peak current and total charge became half of those without offset. The experimental data are useful for the operation of the LIS at the BNL.

  3. Effect of the solenoid in various conditions of the laser ion source at Brookhaven National Laboratory

    SciTech Connect

    Ikeda, S.; Kumaki, M.; Kanesue, T.; Okamura, M.

    2016-02-15

    In the laser ion source (LIS) at the Brookhaven National Laboratory (BNL), a solenoid is used to guide the laser ablation plasma and modulate the extracted beam current. Many types of ion species are guided. In some cases, the plasma plume is injected into the solenoid away from the solenoidal axis. To investigate the effects of the solenoid on the beam extracted from the plasma that has different properties, the beam current was measured in the setup of the LIS at the BNL. The beam current of Li, Al, Si, Fe, and Au increased when the magnetic field was applied. For most of the species the peak current and the total charge within a single beam pulse increased around 10 times with a magnetic field less than 100 G. In addition, for some species the rate of increase of the peak currents became smaller when the magnetic flux densities were larger than certain values depending on the species. In this case, the current waveforms were distorted. At the same magnetic field value, the field was more effective on lighter species than on heavier ones. When plasma was injected offset from the axis of the solenoid, peak current and total charge became half of those without offset. The experimental data are useful for the operation of the LIS at the BNL.

  4. AC Loss Analysis on the Superconducting Coupling Magnet in MICE

    SciTech Connect

    Wu, Hong; Wang, Li; Green, Michael; Li, LanKai; Xu, FengYu; Liu, XiaoKun; Jia, LinXinag

    2008-07-08

    A pair of coupling solenoids is used in MICE experiment to generate magnetic field which keeps the muons within the iris of thin RF cavity windows. The coupling solenoids have a 1.5-meter inner diameter and will produce 7.4 T peak magnetic field. Three types of AC losses in coupling solenoid are discussed. The affect of AC losses on the temperature distribution within the cold mass during charging and rapid discharging process is analyzed also. The analysis result will be further confirmed by the experiment of the prototype solenoid for coupling solenoid, which will be designed, fabricated and tested at ICST.

  5. Test Results for HINS Focusing Solenoids at Fermilab

    SciTech Connect

    Tartaglia, M.A.; Orris, D.F.; Terechkine, I.; Tompkins, J.C.; /Fermilab

    2008-08-01

    A focusing lens R&D program is close to completion and industrial production of magnets has begun. Two types of magnets are being built for use in the room temperature RF section at the front end of a superconducting H-minus linac of a High Intensity Neutrino Source. All of the magnets are designed as a solenoid with bucking coils to cancel the field in the vicinity of adjacent RF cavities, and one type incorporates steering dipole corrector coils. We present a summary of the predicted and measured quench and magnetic properties for both R&D and production device samples that have been tested at Fermilab.

  6. Magnetic fields and cancer

    SciTech Connect

    Jones, T.L.

    1993-10-01

    This letter is a response to an article by Savitz and Kaune, EHP 101:76-80. W-L wire code was applied to data from a 1988 Denver study, and an association was reported between high W-L wire code and childhood cancer. This author discusses several studies and provides explanations which weakens the argument that classification error resulted in an appreciable reduction in the association between W-L high wire code and childhood cancer. In conclusion, the fact that new wire code is only weakly correlated with magnetic field measurements (in the same manner as the original W-L wire code) suggests that the newly reported stronger association with childhood cancer is likely due to factors other than magnetic fields. Differential residential mobility and differential residential age are two possible explanations and are suggestive that the reported association may be false.

  7. Status of the pulsed magnetic field electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Mühle, C.; Ratzinger, U.; Bleuel, W.; Jöst, G.; Leible, K.; Schennach, S.; Wolf, B. H.

    1994-04-01

    Synchrotrons like the heavy-ion synchrotron SIS at GSI need an efficient low duty cycle injector (typical 1-pulse/s and 200-μs pulse length). To improve the peak current, an electron cyclotron resonance (ECR) ion source has been designed using a pulsed magnetic field (PuMa) to force ion extraction. We replaced the hexapole of a 10-GHz Minimafios ECR ion source by a vacuum chamber containing a water-cooled bilayered solenoid coil and a decapole permanent magnetic structure. A pulse line feeds the solenoid with a 250-μs pulse which increases the magnetic field in the minimum B region by 0.3 T. This process opens the magnetic bottle along the beam axis resulting in an extracted ion pulse. First tests of the PuMa ECR configuration in cw and pulsed operation are presented and analyzed.

  8. Magnetic field reconnection

    NASA Astrophysics Data System (ADS)

    Axford, W. I.

    The fundamental principles of particle acceleration by magnetic reconnection in cosmic plasmas are reviewed. The history of reconnection models is traced, and consideration is given to the Kelvin-Helmholtz theorem, the frozen-field theorem, the application of the Kelvin-Helmholtz theorem to a collisionless plasma, solutions to specific reconnection problems, and configurational instability. Diagrams and graphs are provided, and the objections raised by critics of the reconnection theory and/or its astrophysical applications are discussed.

  9. Photonic Magnetic Field Sensor

    DTIC Science & Technology

    2007-11-02

    reduce feedback in fiber optic links can be the basis for excellent magnetic field sensors. Based on the giant magneto-optical ( GMO ) or Faraday...Squids are those based upon the giant magneto-optical ( GMO ) effect in ferrimagnetic materials or YIG garnets and the giant magneto-resistance (GMR...effect in manganese based compounds. The development of the GMO material was mostly motivated by the need for compact, in-line fiber optical

  10. 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.

  11. Low field magnetic resonance imaging

    SciTech Connect

    Pines, Alexander; Sakellariou, Dimitrios; Meriles, Carlos A.; Trabesinger, Andreas H.

    2010-07-13

    A method and system of magnetic resonance imaging does not need a large homogenous field to truncate a gradient field. Spatial information is encoded into the spin magnetization by allowing the magnetization to evolve in a non-truncated gradient field and inducing a set of 180 degree rotations prior to signal acquisition.

  12. Magnetic field switchable dry adhesives.

    PubMed

    Krahn, Jeffrey; Bovero, Enrico; Menon, Carlo

    2015-02-04

    A magnetic field controllable dry adhesive device is manufactured. The normal adhesion force can be increased or decreased depending on the presence of an applied magnetic field. If the magnetic field is present during the entire normal adhesion test cycle which includes both applying a preloading force and measuring the pulloff pressure, a decrease in adhesion is observed when compared to when there is no applied magnetic field. Similarly, if the magnetic field is present only during the preload portion of the normal adhesion test cycle, a decrease in adhesion is observed because of an increased stiffness of the magnetically controlled dry adhesive device. When the applied magnetic field is present during only the pulloff portion of the normal adhesion test cycle, either an increase or a decrease in normal adhesion is observed depending on the direction of the applied magnetic field.

  13. Absolute magnetic helicity and the cylindrical magnetic field

    SciTech Connect

    Low, B. C.

    2011-05-15

    evolution; (iii) twist as a topological property of solenoidal fields versus the linkage properties of open and closed discrete curves treated by Gauss, Caligarneau, Berger, and Prior; and (iv) the change of absolute helicity by resistive diffusion. These are important hydromagnetic properties of twisted magnetic fields in the million-degree hot, highly conducting corona of the Sun.

  14. Superhorizon magnetic fields

    NASA Astrophysics Data System (ADS)

    Campanelli, Leonardo

    2016-03-01

    We analyze the evolution of superhorizon-scale magnetic fields from the end of inflation till today. Whatever is the mechanism responsible for their generation during inflation, we find that a given magnetic mode with wave number k evolves, after inflation, according to the values of k ηe , nk , and Ωk , where ηe is the conformal time at the end of inflation, nk is the number density spectrum of inflation-produced photons, and Ωk is the phase difference between the two Bogoliubov coefficients which characterize the state of that mode at the end of inflation. For any realistic inflationary magnetogenesis scenario, we find that nk-1≪|k ηe|≪1 , and three evolutionary scenarios are possible: (i) |Ωk∓π |=O (1 ) , in which case the evolution of the magnetic spectrum Bk(η ) is adiabatic, a2Bk(η )=const , with a being the expansion parameter; (ii) |Ωk∓π |≪|k ηe| , in which case the evolution is superadiabatic, a2Bk(η )∝η ; (iii) |k ηe|≪|Ωk∓π |≪1 or |k ηe|˜|Ωk∓π |≪1 , in which case an early phase of adiabatic evolution is followed, after a time η⋆˜|Ωk∓π |/k , by a superadiabatic evolution. Once a given mode reenters the horizon, it remains frozen into the plasma and then evolves adiabatically till today. As a corollary of our results, we find that inflation-generated magnetic fields evolve adiabatically on all scales and for all times in conformal-invariant free Maxwell theory, while they evolve superadiabatically after inflation on superhorizon scales in the nonconformal-invariant Ratra model, where the inflaton is kinematically coupled to the electromagnetic field. The latter result supports and, somehow, clarifies our recent claim that the Ratra model can account for the presence of cosmic magnetic fields without suffering from both backreaction and strong-coupling problems.

  15. Electric and magnetic fields

    NASA Technical Reports Server (NTRS)

    Kaufman, H. R.; Robinson, R. S.; Etters, R. D.

    1982-01-01

    A number of energy momentum anomalies are described that result from the use of Abraham-Lorentz electromagnetic theory. These anomalies have in common the motion of charged bodies or current carrying conductors relative to the observer. The anomalies can be avoided by using the nonflow approach, based on internal energy of the electromagnetic field. The anomalies can also be avoided by using the flow approach, if all contributions to flow work are included. The general objective of this research is a fundamental physical understanding of electric and magnetic fields which, in turn, might promote the development of new concepts in electric space propulsion. The approach taken is to investigate quantum representations of these fields.

  16. Analytical Study of Stress State in HTS Solenoids

    SciTech Connect

    Barzi, E.; Terzini, E.; /Fermilab

    2009-01-01

    A main challenge for high field solenoids made of in High Temperature Superconductor (HTS) is the large stress developed in the conductor. This is especially constraining for BSCCO, a brittle and strain sensitive ceramic material. To find parametric correlations useful in magnet design, analytical models can be used. A simple model is herein proposed to obtain the radial, azimuthal and axial stresses in a solenoid as a function of size, i.e. self-field, and of the engineering current density for a number of different constraint hypotheses. The analytical model was verified against finite element modeling (FEM) using the same hypotheses of infinite rigidity of the constraints and room temperature properties. FEM was used to separately evaluate the effect of thermal contractions at 4.2 K for BSCCO and YBCO coils. Even though the analytical model allows for a finite stiffness of the constraints, it was run using infinite stiffness. For this reason, FEM was again used to determine how much stresses change when considering an outer stainless steel skin with finite rigidity for both BSCCO and YBCO coils. For a better understanding of the actual loads that high field solenoids made of HTS will be subject to, we have started some analytical studies of stress state in solenoids for a number of constraint hypotheses. This will hopefully show what can be achieved with the present conductor in terms of self-field. The magnetic field (B) exerts a force F = B x J per unit volume. In superconducting magnets, where the field and current density (J) are both high, this force can be very large, and it is therefore important to calculate the stresses in the coil.

  17. Report of the large solenoid detector group

    SciTech Connect

    Hanson, G.G.; Mori, S.; Pondrom, L.G.; Williams, H.H.; Barnett, B.; Barnes, V.; Cashmore, R.; Chiba, M.; DeSalvo, R.; Devlin, T.

    1987-09-01

    This report presents a conceptual design of a large solenoid for studying physics at the SSC. The parameters and nature of the detector have been chosen based on present estimates of what is required to allow the study of heavy quarks, supersymmetry, heavy Higgs particles, WW scattering at large invariant masses, new W and Z bosons, and very large momentum transfer parton-parton scattering. Simply stated, the goal is to obtain optimum detection and identification of electrons, muons, neutrinos, jets, W's and Z's over a large rapidity region. The primary region of interest extends over +-3 units of rapidity, although the calorimetry must extend to +-5.5 units if optimal missing energy resolution is to be obtained. A magnetic field was incorporated because of the importance of identifying the signs of the charges for both electrons and muons and because of the added possibility of identifying tau leptons and secondary vertices. In addition, the existence of a magnetic field may prove useful for studying new physics processes about which we currently have no knowledge. Since hermeticity of the calorimetry is extremely important, the entire central and endcap calorimeters were located inside the solenoid. This does not at the moment seem to produce significant problems (although many issues remain to be resolved) and in fact leads to a very effective muon detector in the central region.

  18. Muscle Motion Solenoid Actuator

    NASA Astrophysics Data System (ADS)

    Obata, Shuji

    It is one of our dreams to mechanically recover the lost body for damaged humans. Realistic humanoid robots composed of such machines require muscle motion actuators controlled by all pulling actions. Particularly, antagonistic pairs of bi-articular muscles are very important in animal's motions. A system of actuators is proposed using the electromagnetic force of the solenoids with the abilities of the stroke length over 10 cm and the strength about 20 N, which are needed to move the real human arm. The devised actuators are based on developments of recent modern electro-magnetic materials, where old time materials can not give such possibility. Composite actuators are controlled by a high ability computer and software making genuine motions.

  19. Reconnection of Magnetic Fields

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Spacecraft observations of steady and nonsteady reconnection at the magnetopause are reviewed. Computer simulations of three-dimensional reconnection in the geomagnetic tail are discussed. Theoretical aspects of the energization of particles in current sheets and of the microprocesses in the diffusion region are presented. Terrella experiments in which magnetospheric reconnection is simulated at both the magnetopause and in the tail are described. The possible role of reconnection in the evolution of solar magnetic fields and solar flares is discussed. A two-dimensional magnetohydrodynamic computer simulation of turbulent reconnection is examined. Results concerning reconnection in Tokamak devices are also presented.

  20. Refrigerator and Solenoid Run Summary August/September 1999

    SciTech Connect

    Rucinski, R.; /Fermilab

    1999-09-20

    The helium refrigerator was cooled down and operated for the third time since its installation. D-Zero's 2 Tesla superconducting solenoid was cooled down and operated for its second time since its installation into the D-Zero detector. This engineering note summarizes the cryogenic aspects of the test run and performance measurements made. The main purpose of this run was to do field mapping of the solenoid with different combinations of field polarity on the Solenoid and CF iron magnets. This was accomplished. A second purpose was to test the lower field joint repair that was done in January 1999. This field joint had a measurable voltage drop across the soldered bus splice. The repair was an undoing of the joint, extensive cleaning of the bus, and then welding the splice. The repair was successful, no voltage drop was measured and the magnet behaved nicely. A parasitic purpose was to get some operating time on the refrigerator, measure the refrigeration performance, and measure the heat leak in the VLPC lines mounted on the detector platform. Refrigerator performance was spot checked, and was found to be 60 watts (10%) less than generic operating curves. At this level of performance, the operating margin for the full solenoid and VLPC system will be 75 watts (15%) which is somewhat uncomfortable from an operational stand point. The VLPC lines were operated and heat leak numbers of around 40 watts was measured for each pipe section including the supply u-tubes to the detector, the bayonet can, valve box on the platform and the piping back to the refrigerator valve box. Another purpose of the test run was to test the compatibility of other detector components with the new central magnetic field environment. I do not know the results of these tests.

  1. Progress on the Fabrication and Testing of the MICE Spectrometer Solenoids

    SciTech Connect

    Virostek, Steve; Green, M.A.; Li, Derun; Zisman, Michael

    2009-05-19

    The Muon Ionization Cooling Experiment (MICE) is an international collaboration that will demonstrate ionization cooling in a section of a realistic cooling channel using a muon beam at Rutherford Appleton Laboratory (RAL) in the UK. At each end of the cooling channel a spectrometer solenoid magnet consisting of five superconducting coils will provide a 4 tesla uniform field region. The scintillating fiber tracker within the magnet bore will measure the muon beam emittance as it enters and exits the cooling channel. The 400 mm diameter warm bore, 3 meter long magnets incorporate a cold mass consisting of two coil sections wound on a single aluminum mandrel: a three-coil spectrometer magnet and a two-coil section that matches the solenoid uniform field into the MICE cooling channel. The fabrication of the first of two spectrometer solenoids has been completed, and preliminary testing of the magnet is nearly complete. The key design features of the spectrometer solenoid magnets are presented along with a summary of the progress on the training and testing of the first magnet.

  2. The effects of pseudo magnetic fields in molecular spectra and scattering

    SciTech Connect

    Kendrick, B.

    1996-12-31

    Pseudo magnetic fields appear in the Born-Oppenheimer method for molecules when conical intersections or electronic angular momenta are taken into account. These fields are not real magnetic fields but they have the same mathematical properties and can lead to real observable effects in the dynamics of molecules. A general vector potential (gauge theory) approach for including these field effects in the Born-Oppenheimer method is introduced and applied to H + O{sub 2} scattering and the vibrational spectrum of Na{sub 3}(X) for zero total angular momentum (J = 0). The scattering results for HO{sub 2} show significant shifts in the resonance energies and lifetimes due to a magnetic solenoid type field originating from the C{sub 2v} conical intersection in HO{sub 2}. Significant changes in the state-to-state transition probabilities are also observed. The non-degenerate A{sub 1} and A{sub 2} vibrational spectra of Na{sub 3}(X) show significant shifts in the energy levels due to a magnetic solenoid type field originating from the D{sub 3h} conical intersection in Na{sub 3}. These two examples show that the effects of pseudo magnetic fields can be significant and in many cases they must be included in order to obtain agreement between theory and experiment. The newly developed gauge theory techniques for treating pseudo magnetic fields are also relevant for including the effects of real magnetic fields.

  3. A Comparison of the Availability and Failure Modes of the BaBar Superconducting Solenoid with Similar Magnets at Other High Energy Physics Laboratories

    SciTech Connect

    Knodel, Mallory

    2003-09-05

    One of the key technologies in the BaBar detector is the 1.5 T superconducting solenoid. It is imperative that this device operate reliably at its nominal current to allow data taking. While this system is available for physics 98.8% of the time, further improvements are desirable. The object of this project is to survey similar magnet systems, for example those at KEK (Belle), Fermilab (D0 and CDF), DESY (H1 and ZEUS), and CERN (ALEPH and DELPHI), to see how often such magnets stop functioning properly and what the root causes of the failures are. A survey was carried out via e-mail and telephone calls. Information was obtained regarding the operation of superconducting magnets, specifically the BaBar magnet and its ancillary systems, as well as an overview of the use of other such magnets both in the US and overseas. In this work, failure modes will be investigated and compared to the BaBar operational experience. Future investigations can now assess the feasibility of reducing the time the BaBar magnet is nonoperational and unavailable for physics research.

  4. Photonic Magnetic Field Sensor

    NASA Astrophysics Data System (ADS)

    Wyntjes, Geert

    2002-02-01

    Small, in-line polarization rotators or isolators to reduce feedback in fiber optic links can be the basis for excellent magnetic field sensors. Based on the giant magneto-optical (GMO) or Faraday effect in iron garnets, they with a magnetic field of a few hundred Gauss, (20 mT) for an interaction length for an optical beam of a few millimeters achieve a polarization rotation or phase shift of 45 deg (1/8 cycle). When powered by a small laser diode, with the induced linear phase shift recovered at the shot noise limit, we have demonstrated sensitivities at the 3.3 nT/Hz1/2 level for frequencies from less than 1 Hz to frequencies into the high kHz range. Through further improvements; an increase in interaction length, better materials and by far the greatest factor, the addition of a flux concentrator, sensitivities at the pT/Hz1/2 level appear to be within reach. We will detail such a design and discuss the issues that may limit achieving these goals.

  5. The Heliospheric Magnetic Field

    NASA Astrophysics Data System (ADS)

    Owens, Mathew J.; Forsyth, Robert J.

    2013-12-01

    The heliospheric magnetic field (HMF) is the extension of the coronal magnetic field carried out into the solar system by the solar wind. It is the means by which the Sun interacts with planetary magnetospheres and channels charged particles propagating through the heliosphere. As the HMF remains rooted at the solar photosphere as the Sun rotates, the large-scale HMF traces out an Archimedean spiral. This pattern is distorted by the interaction of fast and slow solar wind streams, as well as the interplanetary manifestations of transient solar eruptions called coronal mass ejections. On the smaller scale, the HMF exhibits an array of waves, discontinuities, and turbulence, which give hints to the solar wind formation process. This review aims to summarise observations and theory of the small- and large-scale structure of the HMF. Solar-cycle and cycle-to-cycle evolution of the HMF is discussed in terms of recent spacecraft observations and pre-spaceage proxies for the HMF in geomagnetic and galactic cosmic ray records.

  6. A 15-T Pulsed Solenoid for a High-Power Target Experiment

    SciTech Connect

    Kirk,H.G.; Efthymiopoulos, I.; Fabich, A.; Haug, R.; Titus, P.; McDonald, K. T.; Bennett, J. R. J.; Edgecock, T. R.

    2006-06-26

    The MERIT experiment, to be run at CERN in 2007, is a proof-of-principle test for a target system that converts a 4-MW proton beam into a high-intensity muon beam for either a neutrino factory complex or a muon collider. The target system is based on a free mercury jet that intercepts an intense proton beam inside a 15-T solenoidal magnetic field. Here, we describe the design and initial performance of the 15-T, liquid-nitrogen-precooled, copper solenoid magnet.

  7. A 15-T Pulsed Solenoid for a High-Power Target Experiment

    SciTech Connect

    Kirk,H.G.; Efthymiopoulos, I.; Fabich, A.; Haug, F.; Pereira, H.; Titus, P.; McDonald, K.T.; Bennett, J.R.J.

    2008-06-23

    The MERIT experiment, which ran at CERN in 2007, is a proof-of-principle test for a target system that converts a 4-MW proton beam into a high-intensity muon beam for either a neutrino factory complex or a muon collider. The target system is based on a free mercury jet that intercepts an intense proton beam inside a 15-T solenoidal magnetic field. Here, we describe the design and performance of the 15-T, liquid-nitrogen-precooled, copper solenoid magnet.

  8. Plasma shape control by pulsed solenoid on laser ion source

    DOE PAGES

    Sekine, M.; Ikeda, S.; Romanelli, M.; ...

    2015-05-28

    A Laser ion source (LIS) provides high current heavy ion beams with a very simple mechanical structure. Plasma is produced by a pulsed laser ablation of a solid state target and ions are extracted by an electric field. It was difficult to manipulate the beam parameters of a LIS, since the plasma condition could only be adjusted by the laser irradiation condition. To enhance flexibility of LIS operation, we employed a pulsed solenoid in the plasma drift section and investigated the effect of the solenoid field on singly charged iron beams. The experimentally obtained current profile was satisfactorily controlled bymore » the pulsed magnetic field. Thus, this approach may also be useful to reduce beam emittance of a LIS.« less

  9. Plasma shape control by pulsed solenoid on laser ion source

    SciTech Connect

    Sekine, M.; Ikeda, S.; Romanelli, M.; Kumaki, M.; Fuwa, Y.; Kanesue, T.; Hayashizaki, N.; Lambiase, R.; Okamura, M.

    2015-05-28

    A Laser ion source (LIS) provides high current heavy ion beams with a very simple mechanical structure. Plasma is produced by a pulsed laser ablation of a solid state target and ions are extracted by an electric field. It was difficult to manipulate the beam parameters of a LIS, since the plasma condition could only be adjusted by the laser irradiation condition. To enhance flexibility of LIS operation, we employed a pulsed solenoid in the plasma drift section and investigated the effect of the solenoid field on singly charged iron beams. The experimentally obtained current profile was satisfactorily controlled by the pulsed magnetic field. Thus, this approach may also be useful to reduce beam emittance of a LIS.

  10. Plasma shape control by pulsed solenoid on laser ion source

    NASA Astrophysics Data System (ADS)

    Sekine, M.; Ikeda, S.; Romanelli, M.; Kumaki, M.; Fuwa, Y.; Kanesue, T.; Hayashizaki, N.; Lambiase, R.; Okamura, M.

    2015-09-01

    A Laser ion source (LIS) provides high current heavy ion beams with a very simple mechanical structure. Plasma is produced by a pulsed laser ablation of a solid state target and ions are extracted by an electric field. However, it was difficult to manipulate the beam parameters of a LIS, since the plasma condition could only be adjusted by the laser irradiation condition. To enhance flexibility of LIS operation, we employed a pulsed solenoid in the plasma drift section and investigated the effect of the solenoid field on singly charged iron beams. The experimentally obtained current profile was satisfactorily controlled by the pulsed magnetic field. This approach may also be useful to reduce beam emittance of a LIS.

  11. Magnetic Fields: Visible and Permanent.

    ERIC Educational Resources Information Center

    Winkeljohn, Dorothy R.; Earl, Robert D.

    1983-01-01

    Children will be able to see the concept of a magnetic field translated into a visible reality using the simple method outlined. Standard shelf paper, magnets, iron filings, and paint in a spray can are used to prepare a permanent and well-detailed picture of the magnetic field. (Author/JN)

  12. R&D ERL: HTS Solenoid

    SciTech Connect

    Gupta, R.; Muratore, J.; Plate, S.

    2010-01-01

    An innovative feature of the ERL project is the use of a solenoid made with High Temperature Superconductor (HTS) with the Superconducting RF cavity. The HTS solenoid design offers many advantages because of several unique design features. Typically the solenoid is placed outside the cryostat which means that the beam gets significantly defused before a focusing element starts. In the current design, the solenoid is placed inside the cryostat which provides an early focusing structure and thus a significant reduction in the emittance of the electron beam. In addition, taking full advantage of the high critical temperature of HTS, the solenoid has been designed to reach the required field at {approx}77 K, which can be obtained with liquid nitrogen. This significantly reduces the cost of testing and allows a variety of critical pre-tests which would have been prohibitively expensive at 4 K in liquid helium because of the additional requirements of cryostat and associated facilities.

  13. D0 Solenoid Commissioning September 1998

    SciTech Connect

    Rucinski, R.; /Fermilab

    1998-10-12

    D-Zero installed a new 2 Tesla superconducting solenoid magnet into the central tracking region of the D-Zero detector. This report documents the cryogenic performance of the superconducting solenoid during its first cryogenic operation at Fermilab. By necessity, the liquid helium refrigerator was also operated. This was the second time the refrigerator plant has been operated. The refrigerator's performance is also documented herein.

  14. MUON COLLIDERS - IONIZATION COOLING AND SOLENOIDS.

    SciTech Connect

    PARSA,Z.

    1999-03-29

    For a muon collider, to obtain the needed luminosity, the phase space volume must be greatly reduced within the muon life time. The ionization cooling is the preferred method used to compress the phase space and reduce the emittance to obtain high luminosity muon beams. Alternating solenoid lattices has been proposed for muon colliders, where the emittance are huge. We present an overview, discuss formalism, transfer maps for solenoid magnets and beam dynamics.

  15. Solenoid-Simulation Circuit

    NASA Technical Reports Server (NTRS)

    Simon, R. A.

    1986-01-01

    Electrical properties of solenoids imitated for tests of control circuits. Simulation circuit imitates voltage and current responses of two engine-controlling solenoids. Used in tests of programs of digital engine-control circuits, also provides electronic interface with circuits imitating electrical properties of pressure sensors and linear variable-differential transformers. Produces voltages, currents, delays, and discrete turnon and turnoff signals representing operation of solenoid in engine-control relay. Many such circuits used simulating overall engine circuitry.

  16. Fast superconducting magnetic field switch

    DOEpatents

    Goren, Yehuda; Mahale, Narayan K.

    1996-01-01

    The superconducting magnetic switch or fast kicker magnet is employed with electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater that the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles.

  17. Fast superconducting magnetic field switch

    DOEpatents

    Goren, Y.; Mahale, N.K.

    1996-08-06

    The superconducting magnetic switch or fast kicker magnet is employed with electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater that the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles. 6 figs.

  18. Martian external magnetic field proxies

    NASA Astrophysics Data System (ADS)

    Langlais, Benoit; Civet, Francois

    2015-04-01

    Mars possesses no dynamic magnetic field of internal origin as it is the case for the Earth or for Mercury. Instead Mars is characterized by an intense and localized magnetic field of crustal origin. This field is the result of past magnetization and demagnetization processes, and reflects its evolution. The Interplanetary Magnetic Field (IMF) interacts with Mars' ionized environment to create an external magnetic field. This external field is weak compared to lithospheric one but very dynamic, and may hamper the detailed analysis of the internal magnetic field at some places or times. Because there are currently no magnetic field measurements made at Mars' surface, it is not possible to directly monitor the external field temporal variability as it is done in Earth's ground magnetic observatories. In this study we examine to indirect ways of quantifying this external field. First we use the Advanced Composition Explorer (ACE) mission which measures the solar wind about one hour upstream of the bow-shock resulting from the interaction between the solar wind and the Earth's internal magnetic field. These measurements are extrapolated to Mars' position taking into account the orbital configurations of the Mars-Earth system and the velocity of particles carrying the IMF. Second we directly use Mars Global Surveyor magnetic field measurements to quantify the level of variability of the external field. We subtract from the measurements the internal field which is otherwise modeled, and bin the residuals first on a spatial and then on a temporal mesh. This allows to compute daily or semi daily index. We present a comparison of these two proxies and demonstrate their complementarity. We also illustrate our analysis by comparing our Martian external field proxies to terrestrial index at epochs of known strong activity. These proxies will especially be useful for upcoming magnetic field measurements made around or at the surface of Mars.

  19. Evolution of twisted magnetic fields

    SciTech Connect

    Zweibel, E.G.; Boozer, A.H.

    1985-02-01

    The magnetic field of the solar corona evolves quasistatically in response to slowly changing photospheric boundary conditions. The magnetic topology is preserved by the low resistivity of the solar atmosphere. We show that a magnetic flux coordinate system simplifies the problem of calculating field evolution with invariant topology. As an example, we calculate the equilibrium of a thin magnetic flux tube with small twist per unit length.

  20. Exposure guidelines for magnetic fields

    SciTech Connect

    Miller, G.

    1987-12-01

    The powerful magnetic fields produced by a controlled fusion experiment at Lawrence Livermore National Laboratory (LLNL) necessitated the development of personnel-exposure guidelines for steady magnetic fields. A literature search and conversations with active researchers showed that it is currently possible to develop preliminary exposure guidelines for steady magnetic fields. An overview of the results of past research into the bioeffects of magnetic fields was compiled, along with a discussion of hazards that may be encountered by people with sickle-cell anemia or medical electronic and prosthetic implants. The LLNL steady magnetic-field exposure guidelines along with a review of developments concerning the safety of time-varying fields were also presented in this compilation. Guidelines developed elsewhere for time varying fields were also given. Further research is needed to develop exposure standards for both steady or time-varying fields.

  1. 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.

  2. First Generation Final Focusing Solenoid For NDCX-I

    SciTech Connect

    Seidl, P. A.; Waldron, W.

    2011-11-09

    This report describes the prototype final focus solenoid (FFS-1G), or 1st generation FFS. In order to limit eddy currents, the solenoid winding consists of Litz wire wound on a non-conductive G-10 tube. For the same reason, the winding pack was inserted into an electrically insulating, but thermally conducting Polypropylene (Cool- Poly© D1202) housing and potted with highly viscous epoxy (to be able to wick the single strands of the Litz wire). The magnet is forced-air cooled through cooling channels. The magnet was designed for water cooling, but he cooling jacket cracked, and therefore cooling (beyond natural conduction and radiation) was exclusively by forced air. Though the design operating point was 8 Tesla, for the majority of running on NDCX-1 it operated up to about 5 Tesla. This was due mostly from limitations of voltage holding at the leads, where discharges at higher pulsed current damaged the leads. Generation 1 was replaced by the 2nd generation solenoid (FFS-2G) about a year later, which has operated reliably up to 8 Tesla, with a better lead design and utilizes water cooling. At this point, FFS-1G was used for plasma source R&D by LBNL and PPPL. The maximum field for those experiments was reduced to 3 Tesla due to continued difficulty with the leads and because higher field was not essential for those experiments. The pulser for the final focusing solenoid is a SCR-switched capacitor bank which produces a half-sine current waveform. The pulse width is ~800us and a charge voltage of 3kV drives ~20kA through the magnet producing ~8T field.

  3. Preliminary result of rapid solenoid for controlling heavy-ion beam parameters of laser ion source

    DOE PAGES

    Okamura, M.; Sekine, M.; Ikeda, S.; ...

    2015-03-13

    To realize a heavy ion inertial fusion driver, we have studied a possibility of laser ion source (LIS). A LIS can provide high current high brightness heavy ion beams, however it was difficult to manipulate the beam parameters. To overcome the issue, we employed a pulsed solenoid in the plasma drift section and investigated the effect of the solenoid field on singly charged iron beams. The rapid ramping magnetic field could enhance limited time slice of the current and simultaneously the beam emittance changed accordingly. This approach may also useful to realize an ion source for HIF power plant.

  4. Vestibular stimulation by magnetic fields

    PubMed Central

    Ward, Bryan K.; Roberts, Dale C.; Della Santina, Charles C.; Carey, John P.; Zee, David S.

    2015-01-01

    Individuals working next to strong static magnetic fields occasionally report disorientation and vertigo. With the increasing strength of magnetic fields used for magnetic resonance imaging (MRI) studies, these reports have become more common. It was recently learned that humans, mice and zebrafish all demonstrate behaviors consistent with constant peripheral vestibular stimulation while inside a strong, static magnetic field. The proposed mechanism for this effect involves a Lorentz force resulting from the interaction of a strong static magnetic field with naturally occurring ionic currents flowing through the inner ear endolymph into vestibular hair cells. The resulting force within the endolymph is strong enough to displace the lateral semicircular canal cupula, inducing vertigo and the horizontal nystagmus seen in normal mice and in humans. This review explores the evidence for interactions of magnetic fields with the vestibular system. PMID:25735662

  5. Magnetic fields around evolved stars

    NASA Astrophysics Data System (ADS)

    Leal-Ferreira, M.; Vlemmings, W.; Kemball, A.; Amiri, N.; Maercker, M.; Ramstedt, S.; Olofsson, G.

    2014-04-01

    A number of mechanisms, such as magnetic fields, (binary) companions and circumstellar disks have been suggested to be the cause of non-spherical PNe and in particular collimated outflows. This work investigates one of these mechanisms: the magnetic fields. While MHD simulations show that the fields can indeed be important, few observations of magnetic fields have been done so far. We used the VLBA to observe five evolved stars, with the goal of detecting the magnetic field by means of water maser polarization. The sample consists in four AGB stars (IK Tau, RT Vir, IRC+60370 and AP Lyn) and one pPN (OH231.8+4.2). In four of the five sources, several strong maser features were detected allowing us to measure the linear and/or circular polarization. Based on the circular polarization detections, we infer the strength of the component of the field along the line of sight to be between ~30 mG and ~330 mG in the water maser regions of these four sources. When extrapolated to the surface of the stars, the magnetic field strength would be between a few hundred mG and a few Gauss when assuming a toroidal field geometry and higher when assuming more complex magnetic fields. We conclude that the magnetic energy we derived in the water maser regions is higher than the thermal and kinetic energy, leading to the conclusion that, indeed, magnetic fields probably play an important role in shaping Planetary Nebulae.

  6. Superconducting solenoids for the MICE channel

    SciTech Connect

    Green, M.A.; Barr, G.; Baynham, D.E.; Rockford, J.H.; Fabbricatore, P.; Farinin, S.; Palmer, R.B.; Rey, J.M.

    2003-05-01

    This report describes the channel of superconductingsolenoids for the proposed international Muon Ionization CoolingExperiment (MICE). MICE consists of two cells of a SFOFO cooling channelthat is similar to that studied in the level 2 study of a neutrinofactory[1]. MICE also consists of two detector solenoids at either end ofthe cooling channel section. The superconducting solenoids for MICEperform three functions. The coupling solenoids, which are largesolenoids around 201.25 MHz RF cavities, couple the muon beam between thefocusing sections as it passes along the cooling channel. The focusingsolenoids are around the liquid hydrogen absorber that reduces themomentum of the muons in all directions. These solenoids generate agradient field along the axis as they reduce the beta of the muon beambefore it enters the absorber. Each detector solenoid system consists offive coils that match the muon beam coming to or from an absorber to a4.0 T uniform solenoidal field section that that contains the particledetectors at the ends of the experiment. There are detector solenoids atthe beginning and at the end of the experiment. This report describes theparameters of the eighteen superconducting coils that make up the MICEmagnetic channel.

  7. Design and testing of the 1.5 T superconducting solenoid for the BABAR detector at PEP-II in SLAC

    SciTech Connect

    O'Connor, T G; Shen, S; Fabbricatore, P; Farinon, S; Musenich, R; Priano, C; Bell, R A; Brendt, M; Burgess, W; Craddock, W; Keller, L; Dormicchi, O; Moreschi, P; Penco, R; Valente, P; Valle, N

    2001-01-26

    The 1.5 Tesla superconducting solenoid is part of the BABAR Detector located in the PEP-II B-Factory machine at the Stanford Linear Accelerator Center. The solenoid has a 2.8 m bore and is 3.7 m long. The two layer solenoid is wound with an aluminum stabilized conductor which is graded axially to produce a {+-} 3% field uniformity in the tracking region. The 24 month fabrication, 3 month installation and 1 month commissioning of the solenoid were completed on time and budget. This paper summarizes the culmination of a 3 year design, fabrication and testing program of the BABAR superconducting solenoid. The work was completed by an international collaboration between Ansaldo, INFN, LLNL, and SLAC. Critical current measurements of the superconducting strand, cable and conductor, cool-down, operation with the thermo-siphon cooling, fast and slow discharges, and magnetic forces are discussed in detail.

  8. The Capacitive Magnetic Field Sensor

    NASA Astrophysics Data System (ADS)

    Zyatkov, D. O.; Yurchenko, A. V.; Balashov, V. B.; Yurchenko, V. I.

    2016-01-01

    The results of a study of sensitive element magnetic field sensor are represented in this paper. The sensor is based on the change of the capacitance with an active dielectric (ferrofluid) due to the magnitude of magnetic field. To prepare the ferrofluid magnetic particles are used, which have a followingdispersion equal to 50 < Ø < 56, 45 < Ø < 50, 40 < Ø < 45 and Ø < 40micron of nanocrystalline alloy of brand 5BDSR. The dependence of the sensitivity of the capacitive element from the ferrofluid with different dispersion of magnetic particles is considered. The threshold of sensitivity and sensitivity of a measuring cell with ferrofluid by a magnetic field was determined. The experimental graphs of capacitance change of the magnitude of magnetic field are presented.

  9. Measurements of magnetic field alignment

    SciTech Connect

    Kuchnir, M.; Schmidt, E.E.

    1987-11-06

    The procedure for installing Superconducting Super Collider (SSC) dipoles in their respective cryostats involves aligning the average direction of their field with the vertical to an accuracy of 0.5 mrad. The equipment developed for carrying on these measurements is described and the measurements performed on the first few prototypes SSC magnets are presented. The field angle as a function of position in these 16.6 m long magnets is a characteristic of the individual magnet with possible feedback information to its manufacturing procedure. A comparison of this vertical alignment characteristic with a magnetic field intensity (by NMR) characteristic for one of the prototypes is also presented. 5 refs., 7 figs.

  10. The MAVEN Magnetic Field Investigation

    NASA Astrophysics Data System (ADS)

    Connerney, J. E. P.; Espley, J.; Lawton, P.; Murphy, S.; Odom, J.; Oliversen, R.; Sheppard, D.

    2015-12-01

    The MAVEN magnetic field investigation is part of a comprehensive particles and fields subsystem that will measure the magnetic and electric fields and plasma environment of Mars and its interaction with the solar wind. The magnetic field instrumentation consists of two independent tri-axial fluxgate magnetometer sensors, remotely mounted at the outer extremity of the two solar arrays on small extensions ("boomlets"). The sensors are controlled by independent and functionally identical electronics assemblies that are integrated within the particles and fields subsystem and draw their power from redundant power supplies within that system. Each magnetometer measures the ambient vector magnetic field over a wide dynamic range (to 65,536 nT per axis) with a resolution of 0.008 nT in the most sensitive dynamic range and an accuracy of better than 0.05 %. Both magnetometers sample the ambient magnetic field at an intrinsic sample rate of 32 vector samples per second. Telemetry is transferred from each magnetometer to the particles and fields package once per second and subsequently passed to the spacecraft after some reformatting. The magnetic field data volume may be reduced by averaging and decimation, when necessary to meet telemetry allocations, and application of data compression, utilizing a lossless 8-bit differencing scheme. The MAVEN magnetic field experiment may be reconfigured in flight to meet unanticipated needs and is fully hardware redundant. A spacecraft magnetic control program was implemented to provide a magnetically clean environment for the magnetic sensors and the MAVEN mission plan provides for occasional spacecraft maneuvers—multiple rotations about the spacecraft x and z axes—to characterize spacecraft fields and/or instrument offsets in flight.

  11. The MAVEN Magnetic Field Investigation

    NASA Technical Reports Server (NTRS)

    Connerney, J. E. P.; Espley, J.; Lawton, P.; Murphy, S.; Odom, J.; Oliversen, R.; Sheppard, D.

    2014-01-01

    The MAVEN magnetic field investigation is part of a comprehensive particles and fields subsystem that will measure the magnetic and electric fields and plasma environment of Mars and its interaction with the solar wind. The magnetic field instrumentation consists of two independent tri-axial fluxgate magnetometer sensors, remotely mounted at the outer extremity of the two solar arrays on small extensions ("boomlets"). The sensors are controlled by independent and functionally identical electronics assemblies that are integrated within the particles and fields subsystem and draw their power from redundant power supplies within that system. Each magnetometer measures the ambient vector magnetic field over a wide dynamic range (to 65,536 nT per axis) with a quantization uncertainty of 0.008 nT in the most sensitive dynamic range and an accuracy of better than 0.05%. Both magnetometers sample the ambient magnetic field at an intrinsic sample rate of 32 vector samples per second. Telemetry is transferred from each magnetometer to the particles and fields package once per second and subsequently passed to the spacecraft after some reformatting. The magnetic field data volume may be reduced by averaging and decimation, when necessary to meet telemetry allocations, and application of data compression, utilizing a lossless 8-bit differencing scheme. The MAVEN magnetic field experiment may be reconfigured in flight to meet unanticipated needs and is fully hardware redundant. A spacecraft magnetic control program was implemented to provide a magnetically clean environment for the magnetic sensors and the MAVEN mission plan provides for occasional spacecraft maneuvers - multiple rotations about the spacecraft x and z axes - to characterize spacecraft fields and/or instrument offsets in flight.

  12. Cosmic Magnetic Fields - An Overview

    NASA Astrophysics Data System (ADS)

    Wielebinski, Richard; Beck, Rainer

    Magnetic fields have been known in antiquity. Aristotle attributes the first of what could be called a scientific discussion on magnetism to Thales, who lived from about 625 BC. In China “magnetic carts” were in use to help the Emperor in his journeys of inspection. Plinius comments that in the Asia Minor province of Magnesia shepherds' staffs get at times “glued” to a stone, a alodestone. In Europe the magnetic compass came through the Arab sailors who met the Portuguese explorers. The first scientific treatise on magnetism, “De Magnete”, was published by William Gilbert who in 1600 described his experiments and suggested that the Earth was a huge magnet. Johannes Kepler was a correspondent of Gilbert and at times suggested that planetary motion was due to magnetic forces. Alas, this concept was demolished by Isaac Newton,who seeing the falling apple decided that gravity was enough. This concept of dealing with gravitational forces only remains en vogue even today. The explanations why magnetic effects must be neglected go from “magnetic energy is only 1% of gravitation” to “magnetic fields only complicate the beautiful computer solutions”. What is disregarded is the fact that magnetic effects are very directional(not omni-directional as gravity) and also the fact that magnetic fields are seen every where in our cosmic universe.

  13. Anisotropic magnetic particles in a magnetic field

    PubMed Central

    Martchenko, Ilya; Mihut, Adriana M.; Bialik, Erik; Hirt, Ann M.; Rufier, Chantal; Menzel, Andreas; Dietsch, Hervé; Linse, Per

    2016-01-01

    We characterize the structural properties of magnetic ellipsoidal hematite colloids with an aspect ratio ρ ≈ 2.3 using a combination of small-angle X-ray scattering and computer simulations. The evolution of the phase diagram with packing fraction φ and the strength of an applied magnetic field B is described, and the coupling between orientational order of magnetic ellipsoids and the bulk magnetic behavior of their suspension addressed. We establish quantitative structural criteria for the different phase and arrest transitions and map distinct isotropic, polarized non-nematic, and nematic phases over an extended range in the φ–B coordinates. We show that upon a rotational arrest of the ellipsoids around φ = 0.59, the bulk magnetic behavior of their suspension switches from superparamagnetic to ordered weakly ferromagnetic. If densely packed and arrested, these magnetic particles thus provide persisting remanent magnetization of the suspension. By exploring structural and magnetic properties together, we extend the often used colloid-atom analogy to the case of magnetic spins. PMID:27722439

  14. Superconducting helical solenoid systems for muon cooling experiment at Fermilab

    SciTech Connect

    Kashikhin, Vladimir S.; Andreev, Nikolai; Johnson, Rolland P.; Kashikhin, Vadim V.; Lamm, Michael J.; Romanov, Gennady; Yonehara, Katsuya; Zlobin, Alexander V.; /Fermilab

    2007-08-01

    Novel configurations of superconducting magnet system for Muon Beam Cooling Experiment is under design at Fermilab. The magnet system has to generate longitudinal and transverse dipole and quadrupole helical magnetic fields providing a muon beam motion along helical orbit. It was found that such complicated field configuration can be formed by a set of circular coils shifted in transverse directions in such a way that their centers lay on the center of the helical beam orbit. Closed beam orbit configurations were also proposed and investigated. This paper describes the magnetic and mechanical designs and parameters of such magnetic system based on a NbTi Rutherford type cable. The helical solenoid fabrication, assembly and quench protection issues are presented.

  15. ITER Central Solenoid support structure analysis

    SciTech Connect

    Freudenberg, Kevin D; Myatt, R.

    2011-01-01

    The ITER Central Solenoid (CS) is comprised of six independent coils held together by a pre-compression support structure. This structure must provide enough preload to maintain sufficient coil-to-coil contact and interface load throughout the current pulse. End of burn (EOB) represents one of the most extreme time-points doing the reference scenario when the currents in the CS3 coils oppose those of CS1 & CS2. The CS structure is performance limited by the room temperature static yield requirements needed to support the roughly 180 MN preload to resist coil separation during operation. This preload is applied by inner and external tie plates along the length of the coil stack by mechanical fastening methods utilizing Superbolt technology. The preloading structure satisfies the magnet structural design criteria of ITER and will be verified during mockup studies. The solenoid is supported from the bottom of the toroidal field (TF) coil casing in both the vertical radial directions. The upper support of the CS coil structure maintains radial registration with the TF coil in the event of vertical disruptions (VDE) loads and earthquakes. All of these structure systems are analyzed via a global finite element analysis (FEA). The model includes a complete sector of the TF coil and the CS coil/structure in one self-consistent analysis. The corresponding results and design descriptions are described in this report.

  16. Magnetic field synthesis for microwave magnetics

    NASA Astrophysics Data System (ADS)

    Morgenthaler, F. R.

    1982-04-01

    The Microwave and Quantum Magnetics Group of the M.I.T. Department of Electrical Engineering and Computer Science undertook a two-year research program directed at developing synthesis procedures that allow magnetostatic and/or magnetoelastic modes to be specially tailored for microwave signal processing applications that include magnetically tunable filters and limiters as well as delay lines that are either linearly dispersive or nondispersive over prescribed bandwidths. Special emphasis was given to devices employing thin films of yttrium iron garnet (YIG) that are blessed with spatially nonuniform dc magnetic fields.

  17. Laser-generated magnetic fields in quasi-hohlraum geometries

    NASA Astrophysics Data System (ADS)

    Pollock, Bradley; Turnbull, David; Ross, Steven; Hazi, Andrew; Ralph, Joseph; Lepape, Sebastian; Froula, Dustin; Haberberger, Dan; Moody, John

    2014-10-01

    Laser-generated magnetic fields of 10--40 T have been produced with 100--4000 J laser drives at Omega EP and Titan. The fields are generated using the technique described by Daido et al. [Phys. Rev. Lett. 56, 846 (1986)], which works by directing a laser through a hole in one plate to strike a second plate. Hot electrons generated in the laser-produced plasma on the second plate collect on the first plate. A strap connects the two plates allowing a current of 10 s of kA to flow and generate a solenoidal magnetic field. The magnetic field is characterized using Faraday rotation, b-dot probes, and proton radiography. Further experiments to study the effect of the magnetic field on hohlraum performance are currently scheduled for Omega. This work was performed under the auspices of the United States Department of Energy by the Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA-27344.

  18. Rotating superconductor magnet for producing rotating lobed magnetic field lines

    DOEpatents

    Hilal, Sadek K.; Sampson, William B.; Leonard, Edward F.

    1978-01-01

    This invention provides a rotating superconductor magnet for producing a rotating lobed magnetic field, comprising a cryostat; a superconducting magnet in the cryostat having a collar for producing a lobed magnetic field having oppositely directed adjacent field lines; rotatable support means for selectively rotating the superconductor magnet; and means for energizing the superconductor magnet.

  19. Enhanced trapped field performance of bulk high-temperature superconductors using split coil, pulsed field magnetization with an iron yoke

    NASA Astrophysics Data System (ADS)

    Ainslie, M. D.; Fujishiro, H.; Mochizuki, H.; Takahashi, K.; Shi, Y.-H.; Namburi, D. K.; Zou, J.; Zhou, D.; Dennis, A. R.; Cardwell, D. A.

    2016-07-01

    Investigating and predicting the magnetization of bulk superconducting materials and developing practical magnetizing techniques is crucial to using them as trapped field magnets in engineering applications. The pulsed field magnetization (PFM) technique is considered to be a compact, mobile and relative inexpensive way to magnetize bulk samples, requiring shorter magnetization times (on the order of milliseconds) and a smaller and less complicated magnetization fixture; however, the trapped field produced by PFM is generally much smaller than that of slower zero field cooling or field cooling techniques, particularly at lower operating temperatures. In this paper, the PFM of two, standard Ag-containing Gd-Ba-Cu-O samples is carried out using two types of magnetizing coils: (1) a solenoid coil, and (2) a split coil, both of which make use of an iron yoke to enhance the trapped magnetic field. It is shown that a significantly higher trapped field can be achieved using a split coil with an iron yoke, and in order to explain these how this arrangement works in detail, numerical simulations using a 2D axisymmetric finite element method based on the H -formulation are carried to qualitatively reproduce and analyze the magnetization process from both electromagnetic and thermal points of view. It is observed that after the pulse peak significantly less flux exits the bulk when the iron core is present, resulting in a higher peak trapped field, as well as more overall trapped flux, after the magnetization process is complete. The results have important implications for practical applications of bulk superconductors as such a split coil arrangement with an iron yoke could be incorporated into the design of a portable, high magnetic field source/magnet to enhance the available magnetic field or in an axial gap-type bulk superconducting electric machine, where iron can be incorporated into the stator windings to (1) improve the trapped field from the magnetization process

  20. Evaluation of radio frequency microcoils as nuclear magnetic resonance detectors in low-homogeneity high-field superconducting magnets

    NASA Astrophysics Data System (ADS)

    Wright, A. C.; Neideen, T. A.; Magin, R. L.; Norcross, J. A.

    1998-11-01

    We describe here experiments evaluating the performance of solenoidal radio frequency probes having submillimeter dimensions (microcoils) as detectors for liquid nuclear magnetic resonance (NMR) in very low-homogeneity (100 ppm/cm) magnetic fields. Performance is based on the measured H2O linewidth. A series of solenoidal microcoils having sample volumes 8, 53, and 593 nl were filled with distilled H2O and evaluated for smallest obtainable unshimmed NMR spectral linewidths in a vertical bore superconducting magnet, stabilized at 5.9 T (1H frequency=250 MHz). The smallest microcoil (472 μm diameter) gave a smallest H2O linewidth of 525 Hz, 25 times smaller than that from a standard 5.7 mm probe. Linewidth increased approximately as the square root of sample volume. For comparison, shimmed H2O linewidths using the same microcoils in a high-homogeneity (0.1 ppm/cm) NMR magnet were also measured. Shimmed linewidths in the high-homogeneity magnet were two orders of magnitude smaller and exhibited a similar dependence on volume. The results demonstrate that by using microcoils the volume over which the polarizing magnetic field must meet a specified homogeneity can be significantly reduced, which would be advantageous for smaller, less expensive NMR systems.

  1. Standing helicon induced by a rapidly bent magnetic field in plasmas

    NASA Astrophysics Data System (ADS)

    Takahashi, Kazunori; Takayama, Sho; Komuro, Atsushi; Ando, Akira; Plasma physics Team

    2016-09-01

    An electron energy probability function and an rf magnetic field are measured in an rf hydrogen helicon source, where axial and transverse static magnetic fields are applied to the source by solenoids and to the diffusion chamber by filter magnets, respectively. It is demonstrated that the helicon wave is reflected by the rapidly bent magnetic field and the resultant standing wave heats the electrons between the source and the magnetic filter, while the electron cooling effect by the magnetic filter is maintained. It is interpreted that the standing wave is generated by the presence of spatially localized change of a refractive index. The application to the hydrogen negative ion source used for the neutral beam injection system for fusion plasma heating is discussed. This work is partially supported by grant-in-aid for scientific research (16H04084 and 26247096) from the Japan Society for the Promotion of Science.

  2. Preflare magnetic and velocity fields

    NASA Technical Reports Server (NTRS)

    Hagyard, M. J.; Gaizauskas, V.; Chapman, G. A.; Deloach, A. C.; Gary, G. A.; Jones, H. P.; Karpen, J. T.; Martres, M.-J.; Porter, J. G.; Schmeider, B.

    1986-01-01

    A characterization is given of the preflare magnetic field, using theoretical models of force free fields together with observed field structure to determine the general morphology. Direct observational evidence for sheared magnetic fields is presented. The role of this magnetic shear in the flare process is considered within the context of a MHD model that describes the buildup of magnetic energy, and the concept of a critical value of shear is explored. The related subject of electric currents in the preflare state is discussed next, with emphasis on new insights provided by direct calculations of the vertical electric current density from vector magnetograph data and on the role of these currents in producing preflare brightenings. Results from investigations concerning velocity fields in flaring active regions, describing observations and analyses of preflare ejecta, sheared velocities, and vortical motions near flaring sites are given. This is followed by a critical review of prevalent concepts concerning the association of flux emergence with flares

  3. Magnetic Field of Strange Dwarfs

    NASA Astrophysics Data System (ADS)

    Baghdasaryan, D. S.

    2016-03-01

    The generation of a magnetic field in a strange quark star owing to differential rotation of the superfluid and superconducting quark core relative to the normal electron-nuclear crust of the star is examined. The maximum possible magnetic field on the surface is estimated for various models of strange dwarfs. Depending on the configuration parameters, i.e., the mass M and radius R of the star, a range of 103-105 G is found. These values of the magnetic field may be an additional condition for identification of strange dwarfs among the extensive class of observed white dwarfs.

  4. AC photovoltaic module magnetic fields

    SciTech Connect

    Jennings, C.; Chang, G.J.; Reyes, A.B.; Whitaker, C.M.

    1997-12-31

    Implementation of alternating current (AC) photovoltaic (PV) modules, particularly for distributed applications such as PV rooftops and facades, may be slowed by public concern about electric and magnetic fields (EMF). This paper documents magnetic field measurements on an AC PV module, complementing EMF research on direct-current PV modules conducted by PG and E in 1993. Although not comprehensive, the PV EMF data indicate that 60 Hz magnetic fields (the EMF type of greatest public concern) from PV modules are comparable to, or significantly less than, those from household appliances. Given the present EMF research knowledge, AC PV module EMF may not merit considerable concern.

  5. Magnetoconvection in sheared magnetic fields

    SciTech Connect

    Bian, N. H.; Garcia, O. E.

    2008-10-15

    The development of magnetoconvection in a sheared magnetic field is investigated. The equilibrium magnetic field B{sub 0} is horizontal and its orientation varies linearly along the vertical axis. Preliminary consideration of the transition from the inertial to the viscous regime of the gravitational resistive interchange instability, reveals that the latter is characterized by the existence of viscoresistive boundary layers of vertical width which scales as Q{sup -1/6}, where Q is the Chandrasekhar number. The situation is analogous to the one encountered in magnetically confined laboratory plasmas, where convective flows are constrained by the magnetic shear to develop in boundary layers located around resonant magnetic surfaces in order to fulfill the 'interchange condition'k{center_dot}B{sub 0}=0, where k is the wave vector of the magnetic perturbation. It follows that when the effect of thermal diffusion is taken into account in the process, convection can only occur above a certain critical value of the Rayleigh number which scales as Q{sup 2/3} for large Q. At the onset, the convection pattern is a superposition of identically thin convective rolls everywhere aligned with the local magnetic field lines and which therefore adopt the magnetic field geometry, a situation also reminiscent of the penumbra of sunspots. Using this degeneracy, equations describing the weakly nonlinear state are obtained and discussed. A reduced magnetohydrodynamic description of magnetoconvection is introduced. Since it is valid for arbitrary magnetic field configurations, it allows a simple extension to the case where there exists an inclination between the direction of gravity and the plane spanned by the equilibrium magnetic field. These reduced magnetohydrodynamic equations are proposed as a powerful tool for further investigations of magnetoconvection in more complex field line geometries.

  6. Preface: Cosmic magnetic fields

    NASA Astrophysics Data System (ADS)

    Kosovichev, Alexander

    2015-02-01

    Recent advances in observations and modeling have opened new perspectives for the understanding of fundamental dynamical processes of cosmic magnetism, and associated magnetic activity on the Sun, stars and galaxies. The goal of the Special Issue is to discuss the progress in solar physics and astrophysics, similarities and differences in phenomenology and physics of magnetic phenomena on the Sun and other stars. Space observatories, ground-based telescopes, and new observational methods have provided tremendous amount of data that need to be analyzed and understood. The solar observations discovered multi-scale organization of solar activity, dramatically changing current paradigms of solar variability. On the other side, stellar observations discovered new regimes of dynamics and magnetism that are different from the corresponding solar phenomena, but described by the same physics. Stars represent an astrophysical laboratory for studying the dynamical, magnetic and radiation processes across a broad range of stellar masses and ages. These studies allow us to look at the origin and evolution of our Sun, whereas detailed investigations of the solar magnetism give us a fundamental basis for interpretation and understanding of unresolved stellar data.

  7. RF breakdown of 805 MHz cavities in strong magnetic fields

    SciTech Connect

    Bowring, D.; Stratakis, D.; Kochemirovskiy, A.; Leonova, M.; Moretti, A.; Palmer, M.; Peterson, D.; Yonehara, K.; Freemire, B.; Lane, P.; Torun, Y.; Haase, A.

    2015-05-03

    Ionization cooling of intense muon beams requires the operation of high-gradient, normal-conducting RF structures in the presence of strong magnetic fields. We have measured the breakdown rate in several RF cavities operating at several frequencies. Cavities operating within solenoidal magnetic fields B > 0.25 T show an increased RF breakdown rate at lower gradients compared with similar operation when B = 0 T. Ultimately, this breakdown behavior limits the maximum safe operating gradient of the cavity. Beyond ionization cooling, this issue affects the design of photoinjectors and klystrons, among other applications. We have built an 805 MHz pillbox-type RF cavity to serve as an experimental testbed for this phenomenon. This cavity is designed to study the problem of RF breakdown in strong magnetic fields using various cavity materials and surface treatments, and with precise control over sources of systematic error. We present results from tests in which the cavity was run with all copper surfaces in a variety of magnetic fields.

  8. Magnetic fields during galaxy mergers

    NASA Astrophysics Data System (ADS)

    Rodenbeck, Kai; Schleicher, Dominik R. G.

    2016-09-01

    Galaxy mergers are expected to play a central role for the evolution of galaxies and may have a strong effect on their magnetic fields. We present the first grid-based 3D magnetohydrodynamical simulations investigating the evolution of magnetic fields during merger events. For this purpose, we employed a simplified model considering the merger event of magnetized gaseous disks in the absence of stellar feedback and without a stellar or dark matter component. We show that our model naturally leads to the production of two peaks in the evolution of the average magnetic field strength within 5 kpc, within 25 kpc, and on scales in between 5 and 25 kpc. The latter is consistent with the peak in the magnetic field strength previously reported in a merger sequence of observed galaxies. We show that the peak on the galactic scale and in the outer regions is most likely due to geometrical effects, as the core of one galaxy enters the outskirts of the other one. In addition, the magnetic field within the central ~5 kpc is physically enhanced, which reflects the enhancement in density that is due to efficient angular momentum transport. We conclude that high-resolution observations of the central regions will be particularly relevant for probing the evolution of magnetic field structures during merger events.

  9. Linear decomposition method for approximating arbitrary magnetic field profiles by optimization of discrete electromagnet currents

    SciTech Connect

    Tejero, E. M.; Gatling, G.

    2009-03-15

    A method for approximating arbitrary axial magnetic field profiles for a given solenoidal electromagnet coil array is described. The method casts the individual contributions from each coil as a truncated orthonormal basis for the space within the array. This truncated basis allows for the linear decomposition of an arbitrary profile function, which returns the appropriate currents for each coil to best reproduce the desired profile. We present the mathematical details of the method along with a detailed example of its use. The results from the method are used in a simulation and compared with magnetic field measuremen0008.

  10. Use of a probing pulsed magnetic field for determining plasma parameters

    NASA Astrophysics Data System (ADS)

    Rousskikh, A. G.; Oreshkin, V. I.; Zhigalin, A. S.; Yushkov, G. Yu.

    2016-11-01

    A novel, simple, and readily usable method is proposed for measuring the electrical conductivity and temperature of a plasma. The method is based on the interaction of the test plasma with a pulsed magnetic field. The electric signals induced by the magnetic field in the circuits of two probes (miniature solenoids), one immersed in the test plasma and the other placed outside the plasma, provide data for estimating the plasma parameters. The method was verified experimentally by determining the parameters of the plasma flows generated in the cathode spots high-current pulsed vacuum arcs that were used to form cylindrical shells of bismuth Z-pinch plasma.

  11. Magnetic fields from phase transitions

    NASA Astrophysics Data System (ADS)

    Hindmarsh, Mark; Everett, Allen

    1998-11-01

    The generation of primordial magnetic fields from cosmological phase transitions is discussed, paying particular attention to the electroweak transition and to the various definitions of the ``average'' field that have been put forward. It is emphasized that only the volume average has dynamical significance as a seed for galactic dynamos. On rather general grounds of causality and energy conservation, it is shown that, in the absence of MHD effects that transfer power in the magnetic field from small to large scales, processes occurring at the electroweak transition cannot generate fields stronger than 10-20 G on a scale of 0.5 Mpc. However, it is implausible that this upper bound could ever be reached, as it would require all the energy in the Universe to be turned into a magnetic field coherent at the horizon scale. Non-linear MHD effects seem therefore to be necessary if the electroweak transition is to create a primordial seed field.

  12. Measuring Earth's Magnetic Field Simply.

    ERIC Educational Resources Information Center

    Stewart, Gay B.

    2000-01-01

    Describes a method for measuring the earth's magnetic field using an empty toilet paper tube, copper wire, clear tape, a battery, a linear variable resistor, a small compass, cardboard, a protractor, and an ammeter. (WRM)

  13. The Juno Magnetic Field Investigation

    NASA Astrophysics Data System (ADS)

    Connerney, J. E. P.; Benn, M.; Bjarno, J. B.; Denver, T.; Espley, J.; Jorgensen, J. L.; Jorgensen, P. S.; Lawton, P.; Malinnikova, A.; Merayo, J. M.; Murphy, S.; Odom, J.; Oliversen, R.; Schnurr, R.; Sheppard, D.; Smith, E. J.

    2017-02-01

    The Juno Magnetic Field investigation (MAG) characterizes Jupiter's planetary magnetic field and magnetosphere, providing the first globally distributed and proximate measurements of the magnetic field of Jupiter. The magnetic field instrumentation consists of two independent magnetometer sensor suites, each consisting of a tri-axial Fluxgate Magnetometer (FGM) sensor and a pair of co-located imaging sensors mounted on an ultra-stable optical bench. The imaging system sensors are part of a subsystem that provides accurate attitude information (to ˜20 arcsec on a spinning spacecraft) near the point of measurement of the magnetic field. The two sensor suites are accommodated at 10 and 12 m from the body of the spacecraft on a 4 m long magnetometer boom affixed to the outer end of one of 's three solar array assemblies. The magnetometer sensors are controlled by independent and functionally identical electronics boards within the magnetometer electronics package mounted inside Juno's massive radiation shielded vault. The imaging sensors are controlled by a fully hardware redundant electronics package also mounted within the radiation vault. Each magnetometer sensor measures the vector magnetic field with 100 ppm absolute vector accuracy over a wide dynamic range (to 16 Gauss = 1.6 × 106 nT per axis) with a resolution of ˜0.05 nT in the most sensitive dynamic range (±1600 nT per axis). Both magnetometers sample the magnetic field simultaneously at an intrinsic sample rate of 64 vector samples per second. The magnetic field instrumentation may be reconfigured in flight to meet unanticipated needs and is fully hardware redundant. The attitude determination system compares images with an on-board star catalog to provide attitude solutions (quaternions) at a rate of up to 4 solutions per second, and may be configured to acquire images of selected targets for science and engineering analysis. The system tracks and catalogs objects that pass through the imager field of

  14. Diode magnetic-field influence on radiographic spot size

    SciTech Connect

    Ekdahl, Carl A. Jr.

    2012-09-04

    Flash radiography of hydrodynamic experiments driven by high explosives is a well-known diagnostic technique in use at many laboratories. The Dual-Axis Radiography for Hydrodynamic Testing (DARHT) facility at Los Alamos was developed for flash radiography of large hydrodynamic experiments. Two linear induction accelerators (LIAs) produce the bremsstrahlung radiographic source spots for orthogonal views of each experiment ('hydrotest'). The 2-kA, 20-MeV Axis-I LIA creates a single 60-ns radiography pulse. For time resolution of the hydrotest dynamics, the 1.7-kA, 16.5-MeV Axis-II LIA creates up to four radiography pulses by slicing them out of a longer pulse that has a 1.6-{micro}s flattop. Both axes now routinely produce radiographic source spot sizes having full-width at half-maximum (FWHM) less than 1 mm. To further improve on the radiographic resolution, one must consider the major factors influencing the spot size: (1) Beam convergence at the final focus; (2) Beam emittance; (3) Beam canonical angular momentum; (4) Beam-motion blur; and (5) Beam-target interactions. Beam emittance growth and motion in the accelerators have been addressed by careful tuning. Defocusing by beam-target interactions has been minimized through tuning of the final focus solenoid for optimum convergence and other means. Finally, the beam canonical angular momentum is minimized by using a 'shielded source' of electrons. An ideal shielded source creates the beam in a region where the axial magnetic field is zero, thus the canonical momentum zero, since the beam is born with no mechanical angular momentum. It then follows from Busch's conservation theorem that the canonical angular momentum is minimized at the target, at least in principal. In the DARHT accelerators, the axial magnetic field at the cathode is minmized by using a 'bucking coil' solenoid with reverse polarity to cancel out whatever solenoidal beam transport field exists there. This is imperfect in practice, because of

  15. Magnetic-Field Hazards Bibliography.

    DTIC Science & Technology

    1985-09-01

    Puchalska, I. B., Influence of magnetic fields on frog sciatic nerve , Biochem. Biophys. Res. Comm. 91:118 (1979). 35. Fardon, 3. C., "Effect of magnetic...fields, Bioelectromagnetic 2:357 (1981). 41. Gaffey, C. T. and Tenforde, T. S., Bioelectric properties of frog sciatic nerves during exposure to...available from: U.S. Dept. of Energy, Bonneville Power Administration, Portland, Oregon 97208 (1982). 29. Levy , R. H., and Jones, G. S., "Plasma

  16. Delineation of electric and magnetic field effects of extremely low frequency electromagnetic radiation on transcription

    SciTech Connect

    Greene, J.J.; Skowronski, W.J.; Mullins, J.M.; Nardone, R.M.; Penafiel, M.; Meister, R. )

    1991-01-31

    The relative effects of the electric and magnetic field components of extremely low frequency electromagnetic radiation (ELF) on transcription were examined in human leukemia HL-60 cells. Delineation of the individual field contributions was achieved by irradiating cells in separate concentric compartments of a culture dish within a solenoid chamber. This exposure system produced a homogeneous magnetic field with a coincident electric field whose strength varied directly with distance from the center of the culture dish. Irradiation of HL-60 cells with sine wave ELF at 60 Hz and a field strength of 10 Gauss produced a transient increase in the transcriptional rates which reached a maximum of 50-60% enhancement at 30-120 minutes of irradiation and declined to near basal levels by 18 hours. Comparison of transcription responses to ELF of cells in different concentric compartments revealed that the transcriptional effects were primarily the result of the electric field component with little or no contribution from the magnetic field.

  17. THE EFFECT OF MAGNETIC FIELD ERRORS ON DYNAMICAL FRICTION IN ELECTRON COOLERS.

    SciTech Connect

    FEDOTOV, A.V.; LITVINENKO, V.N.

    2005-05-16

    A proposed luminosity upgrade to the Relativistic Heavy Ion Collider (RHIC) includes a novel electron cooling section [1], which would use -55 MeV electrons to cool fully-ionized 100 GeV/nucleon gold ions. A strong (1-5 T) solenoidal field will be used to magnetize the electrons and thus enhance the dynamical friction force on the ions. The physics of magnetized friction is being simulated for RHIC parameters [2,3,4], using the VORPAL code [5]. Most theoretical treatments for magnetized dynamical friction do not consider the effect of magnetic field errors, except in a parametric fashion. However, field errors can in some cases dramatically reduce the velocity drag and corresponding cooling rate. We present two simple analytical models for the magnetic field errors. The simulated dynamical friction for the case of a perfect solenoidal field is compared with results from these new models. We simulate parameters for the existing cooler of the CELSIUS ring, because recent experiments [6] provide data that will later be used for code validation.

  18. Optical sensor of magnetic fields

    DOEpatents

    Butler, M.A.; Martin, S.J.

    1986-03-25

    An optical magnetic field strength sensor for measuring the field strength of a magnetic field comprising a dilute magnetic semi-conductor probe having first and second ends, longitudinally positioned in the magnetic field for providing Faraday polarization rotation of light passing therethrough relative to the strength of the magnetic field. Light provided by a remote light source is propagated through an optical fiber coupler and a single optical fiber strand between the probe and the light source for providing a light path therebetween. A polarizer and an apparatus for rotating the polarization of the light is provided in the light path and a reflector is carried by the second end of the probe for reflecting the light back through the probe and thence through the polarizer to the optical coupler. A photo detector apparatus is operably connected to the optical coupler for detecting and measuring the intensity of the reflected light and comparing same to the light source intensity whereby the magnetic field strength may be calculated.

  19. Quantum oscillations without magnetic field

    NASA Astrophysics Data System (ADS)

    Liu, Tianyu; Pikulin, D. I.; Franz, M.

    2017-01-01

    When the magnetic field B is applied to a metal, nearly all observable quantities exhibit oscillations periodic in 1 /B . Such quantum oscillations reflect the fundamental reorganization of electron states into Landau levels as a canonical response of the metal to the applied magnetic field. We predict here that, remarkably, in the recently discovered Dirac and Weyl semimetals, quantum oscillations can occur in the complete absence of magnetic field. These zero-field quantum oscillations are driven by elastic strain which, in the space of the low-energy Dirac fermions, acts as a chiral gauge potential. We propose an experimental setup in which the strain in a thin film (or nanowire) can generate a pseudomagnetic field b as large as 15 T and demonstrate the resulting de Haas-van Alphen and Shubnikov-de Haas oscillations periodic in 1 /b .

  20. Magnetic fields in spiral galaxies

    NASA Astrophysics Data System (ADS)

    Beck, Rainer

    2015-12-01

    Radio synchrotron emission, its polarization and Faraday rotation of the polarization angle are powerful tools to study the strength and structure of magnetic fields in galaxies. Unpolarized synchrotron emission traces isotropic turbulent fields which are strongest in spiral arms and bars (20-30 \\upmu G) and in central starburst regions (50-100 \\upmu G). Such fields are dynamically important; they affect gas flows and drive gas inflows in central regions. Polarized emission traces ordered fields, which can be regular or anisotropic turbulent, where the latter originates from isotropic turbulent fields by the action of compression or shear. The strongest ordered fields (10-15 \\upmu G) are generally found in interarm regions. In galaxies with strong density waves, ordered fields are also observed at the inner edges of spiral arms. Ordered fields with spiral patterns exist in grand-design, barred and flocculent galaxies and in central regions. Ordered fields in interacting galaxies have asymmetric distributions and are a tracer of past interactions between galaxies or with the intergalactic medium.—Faraday rotation measures of the diffuse polarized radio emission from galaxy disks reveal large-scale spiral patterns that can be described by the superposition of azimuthal modes; these are signatures of regular fields generated by mean-field dynamos. "Magnetic arms" between gaseous spiral arms may also be products of dynamo action, but need a stable spiral pattern to develop. Helically twisted field loops winding around spiral arms were found in two galaxies so far. Large-scale field reversals, like the one found in the Milky Way, could not yet be detected in external galaxies. In radio halos around edge-on galaxies, ordered magnetic fields with X-shaped patterns are observed. The origin and evolution of cosmic magnetic fields, in particular their first occurrence in young galaxies and their dynamical importance during galaxy evolution, will be studied with

  1. Strong Magnetic Field Characterisation

    DTIC Science & Technology

    2012-04-01

    coils were driven by a pulsed-power system to generate the fields. All the sources were characterised through a series of measurements and modelling... generated for the coils. Options for further investigation were provided. UNCLASSIFIED UNCLASSIFIED This...investigation. The desired field strength was based on assessments [1] from preliminary magnetohydrodynamic ( MHD ) modelling and while not achievable by

  2. Electrostatic acceleration of helicon plasma using a cusped magnetic field

    SciTech Connect

    Harada, S.; Baba, T.; Uchigashima, A.; Iwakawa, A.; Sasoh, A.; Yokota, S.; Yamazaki, T.; Shimizu, H.

    2014-11-10

    The electrostatic acceleration of helicon plasma is investigated using an electrostatic potential exerted between the ring anode at the helicon source exit and an off-axis hollow cathode in the downstream region. In the downstream region, the magnetic field for the helicon source, which is generated by a solenoid coil, is modified using permanent magnets and a yoke, forming an almost magnetic field-free region surrounded by an annular cusp field. Using a retarding potential analyzer, two primary ion energy peaks, where the lower peak corresponds to the space potential and the higher one to the ion beam, are detected in the field-free region. Using argon as the working gas with a helicon power of 1.5 kW and a mass flow rate of 0.21 mg/s, the ion beam energy is on the order of the applied acceleration voltage. In particular, with an acceleration voltage lower than 150 V, the ion beam energy even exceeds the applied acceleration voltage by an amount on the order of the electron thermal energy at the exit of the helicon plasma source. The ion beam energy profile strongly depends on the helicon power and the applied acceleration voltage. Since by this method the whole working gas from the helicon plasma source can, in principle, be accelerated, this device can be applied as a noble electrostatic thruster for space propulsion.

  3. Mechanical analysis and test results of 4-coil superconducting helical solenoid model

    SciTech Connect

    Yu, M.; Andreev, N.; Chlachidze, G.; Johnson, R.P.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Lopes, M.L.; Makarov, A.; Tartaglia, M.; Yonehara, K.; /Fermilab

    2010-01-01

    Novel configurations of helical superconducting magnets for muon beam 6D phase space cooling channels and demonstration experiments are being designed at Fermilab. Operating as needed for the beam cooling in a cryogenic environment, the helical solenoid generates longitudinal and transverse magnetic fields; meanwhile, large Lorentz forces are produced, so rigid coil support structures need to be designed. A short model of a helical solenoid (HS), consisting of four coils and supporting structures, was designed, built and tested at Fermilab. The magnetic and mechanical designs were analyzed using TOSCA and ANSYS. The supporting structures were fabricated and assembled using SSC NbTi cable. Strain gauges were utilized to monitor the deformation of the structures due to both thermal contraction and Lorentz forces. The superconducting coils were trained during the test. The model should prove the design concept, fabrication technology, and the magnet system performance.

  4. MAGNETIC FIELD MEASUREMENTS FOR FAST-CHANGING MAGNETIC FIELDS.

    SciTech Connect

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

    2004-10-03

    Several recent applications for fast ramped magnets have been found that require rapid measurement of the field quality during the ramp. (In one instance, accelerator dipoles will be ramped at 1 T/sec, with measurements needed to the accuracy typically required for accelerators.) We have built and tested a new type of magnetic field measuring system to meet this need. The system consists of 16 stationary pickup windings mounted on a cylinder. The signals induced in the windings in a changing magnetic field are sampled and analyzed to obtain the field harmonics. To minimize costs, printed circuit boards were used for the pickup windings and a combination of amplifiers and ADPs used for the voltage readout system. New software was developed for the analysis. Magnetic field measurements of a model dipole developed for the SIS200 accelerator at GSI are presented. The measurements are needed to insure that eddy currents induced by the fast ramps do not impact the field quality needed for successful accelerator operation.

  5. Insert Coil Test for HEP High Field Magnets Using YBCO Coated Conductor Tapes

    SciTech Connect

    Lombardo, V.; Barzi, E.; Turrioni, D.; Zlobin, A.V.; /Fermilab

    2011-06-15

    The final beam cooling stages of a Muon Collider may require DC solenoid magnets with magnetic fields of 30-50 T. In this paper we present progress in insert coil development using commercially available YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} Coated Conductor. Technological aspects covered in the development, including coil geometry, insulation, manufacturing process and testing are summarized and discussed. Test results of double pancake coils operated in liquid nitrogen and liquid helium are presented and compared with the performance of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} tape short samples.

  6. Magnetic field of the Earth

    NASA Astrophysics Data System (ADS)

    Popov, Aleksey

    2013-04-01

    The magnetic field of the Earth has global meaning for a life on the Earth. The world geophysical science explains: - occurrence of a magnetic field of the Earth it is transformation of kinetic energy of movements of the fused iron in the liquid core of Earth - into the magnetic energy; - the warming up of a kernel of the Earth occurs due to radioactive disintegration of elements, with excretion of thermal energy. The world science does not define the reasons: - drift of a magnetic dipole on 0,2 a year to the West; - drift of lithospheric slabs and continents. The author offers: an alternative variant existing in a world science the theories "Geodynamo" - it is the theory « the Magnetic field of the Earth », created on the basis of physical laws. Education of a magnetic field of the Earth occurs at moving the electric charge located in a liquid kernel, at rotation of the Earth. At calculation of a magnetic field is used law the Bio Savara for a ring electric current: dB = . Magnetic induction in a kernel of the Earth: B = 2,58 Gs. According to the law of electromagnetic induction the Faradey, rotation of a iron kernel of the Earth in magnetic field causes occurrence of an electric field Emf which moves electrons from the center of a kernel towards the mantle. So of arise the radial electric currents. The magnetic field amplifies the iron of mantle and a kernel of the Earth. As a result of action of a radial electric field the electrons will flow from the center of a kernel in a layer of an electric charge. The central part of a kernel represents the field with a positive electric charge, which creates inverse magnetic field Binv and Emfinv When ?mfinv = ?mf ; ?inv = B, there will be an inversion a magnetic field of the Earth. It is a fact: drift of a magnetic dipole of the Earth in the western direction approximately 0,2 longitude, into a year. Radial electric currents a actions with the basic magnetic field of a Earth - it turn a kernel. It coincides with laws

  7. Satellite to study earth's magnetic field

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The Magnetic Field Satellite (Magsat) designed to measure the near earth magnetic field and crustal anomalies is briefly described. A scalar magnetometer to measure the magnitude of the earth's crustal magnetic field and a vector magnetometer to measure magnetic field direction as well as magnitude are included. The mission and its objectives are summarized along with the data collection and processing system.

  8. High Precision Magnetic Field Scanning System for the New Muon g-2 Experiment

    NASA Astrophysics Data System (ADS)

    Hong, Ran; Muon g-2 collaboration Collaboration

    2017-01-01

    The New Muon g-2 Experiment (E989) at Fermilab will measure the anomalous magnetic moment of muon aμ aiming at a precision of 140 ppb. This new experiment will shed light on the long-standing 3.5 standard deviation between the previous muon g-2 measurement (E821) at Brookhaven National Laboratory and the Standard Model calculation, and potentially discover new physics. The New Muon g-2 Experiment measures the precession frequency of muon in a uniform magnetic field, and the magnetic field experienced by the muons needs to be measured with a precision better than 70 ppb. For the measurement of the magnetic field in the muon storage region, the former trolley system from E821 with 17 NMR probes was refurbished and upgraded with new electronics, probes and a modern motion control system. A test solenoid magnet was set up at Argonne National Laboratory for calibrating the NMR probes and the precision studies of systematic uncertainties. In this presentation, we will describe the trolley motion control scheme, the trolley position measurement methods, the electronic system for activating and reading the NMR probes and the test solenoid facility.

  9. Galactic and Intergalactic Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Klein, U.; Fletcher, A.

    This course-tested textbook conveys the fundamentals of magnetic fields and relativistic plasma in diffuse cosmic media, with a primary focus on phenomena that have been observed at different wavelengths. Theoretical concepts are addressed wherever necessary, with derivations presented in sufficient detail to be generally accessible. In the first few chapters the authors present an introduction to various astrophysical phenomena related to cosmic magnetism, with scales ranging from molecular clouds in star-forming regions and supernova remnants in the Milky Way, to clusters of galaxies. Later chapters address the role of magnetic fields in the evolution of the interstellar medium, galaxies and galaxy clusters. The book is intended for advanced undergraduate and postgraduate students in astronomy and physics and will serve as an entry point for those starting their first research projects in the field.

  10. Numerical analysis of the effects of a high gradient magnetic field on flowing erythrocytes in a membrane oxygenator

    NASA Astrophysics Data System (ADS)

    Mitamura, Yoshinori; Okamoto, Eiji

    2015-04-01

    This study was carried out to clarify the effect of a high gradient magnetic field on pressure characteristics of blood in a hollow fiber membrane oxygenator in a solenoid coil by means of numerical analysis. Deoxygenated erythrocytes are paramagnetic, and oxygenated erythrocytes are diamagnetic. Blood changes its magnetic susceptibility depending on whether it is carrying oxygen or not. Motion of blood was analyzed by solving the continuous equation and the Navier-Stokes equation. It was confirmed that oxygenation of deoxygenated blood in the downstream side of the applied magnetic field was effective for pressure rise in a non-uniform magnetic field. The pressure rise was enhanced greatly by an increase in magnetic field intensity. The results suggest that a membrane oxygenator works as an actuator and there is a possibility of self-circulation of blood through an oxygenator in a non-uniform magnetic field.

  11. The Effect of Magnetic Field on HTS Leads What Happens when thePower Fails at RAL?

    SciTech Connect

    Green, Michael A.

    2007-02-14

    The key to being able to operate the MICE superconducting solenoids on small coolers is the use of high temperature superconducting (HTS) leads between the first stage of the cooler and the magnet, which operates at around 4.2 K. Because MICE magnets are not shielded, all of the MICE magnets have a stray magnetic field in the region where the coolers and the HTS leads are located. The behavior of the HTS leads in a magnetic field depends strongly on the HTS material used for the leads and the temperature of the cooler first stage temperature. The HTS leads can be specified to operate at the maximum current for the magnet. This report shows how the HTS leads can be specified for use the MICE magnets. MICE magnets take from 1.3 hours (the tracker solenoids) to 3.7 hours (the coupling magnet) to charge to the highest projected operating currents. If the power fails, the cooler and the upper ends of the HTS leads warm up. The question is how one can discharge the magnet to protect the HTS leads without quenching the MICE magnets. This report describes a method that one can use to protect the HTS leads in the event of a power failure at the Rutherford Appleton Laboratory (RAL).

  12. Photospheric and coronal magnetic fields

    SciTech Connect

    Sheeley, N.R., Jr. )

    1991-01-01

    Research on small-scale and large-scale photospheric and coronal magnetic fields during 1987-1990 is reviewed, focusing on observational studies. Particular attention is given to the new techniques, which include the correlation tracking of granules, the use of highly Zeeman-sensitive infrared spectral lines and multiple lines to deduce small-scale field strength, the application of long integration times coupled with good seeing conditions to study weak fields, and the use of high-resolution CCD detectors together with computer image-processing techniques to obtain images with unsurpassed spatial resolution. Synoptic observations of large-scale fields during the sunspot cycle are also discussed. 101 refs.

  13. The Mice Focusing Solenoids and their Cooling System

    SciTech Connect

    Green, M.A.; Barr, G.; Lau, W.; Senanayake, R.S.; Yang, S.Q.

    2004-05-07

    This report describes the focusing solenoid for the proposed Muon Ionization Cooling Experiment (MICE) [1]. The focusing solenoid consists of a pair of superconducting solenoids that are on a common bobbin. The two coils, which have separate leads, may be operated in the same polarity or at opposite polarity. This report discusses the superconducting magnet design and the cryostat design for the MICE focusing module. Also discussed is how this superconducting magnet can be integrated with a pair of small 4.2 K coolers.

  14. Observations of Interstellar Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Crutcher, R.; Heiles, C.; Troland, T.

    This article describes how interstellar magnetic fields are detected, measured, and mapped, the results of such observations, and the role played by interstellar magnetic fields in the physics of the interstellar medium. A goal of the observations is the measurement of the morphology and strengths of the uniform (Bu) and random (Br) components of magnetic fields. Observational techniques probe either the component of B parallel to the line of sight (B_parallel) or in the plane of the sky (B_⊥). Tracers of B_parallel are Faraday rotation of the position angle of linearly polarized radiation and Zeeman splitting of spectral lines. Tracers of B_⊥ are the strength of synchrotron radiation and linear polarization of syn chrotron radiation and of emission or absorption from dust and spectral lines. Starlight polarization shows that on large spatial scales the Galactic magnetic field is not heavily tangled (B_u/B_r ≈ 0.7 - 1.0), that the field is generally parallel to the Galactic plane near the plane, that the local field points approximately along the local spiral arm (pitch angle 9.4(°) , center of curvature 7.8 kpc distant towards ℓ ≈ -15.4(°) ), and that off the Galactic plane there is considerable small-scale structure to the field. Galactic synchrotron emission shows magnetic spiral arms with a total strength B_t ≈ 6 #55G and B_u ≈ 4 #55G. Pulsar data show evidence for reversals of the field direction with Galactic radius and yield B_r ≈ 5 #55G and B_u ≈ 1.5 #55G; the morphology of the large-scale mean field is consistent with dynamo generation. H I Zeeman detections for diffuse clouds yield B_parallel char 126 5 - 20 #55G with many limits B_parallel #55G. A recent survey of Galactic H I in absorption against extragalactic sources confirms the result that the fields in diffuse clouds are often quite weak. The critical parameter for evaluating the importance of magnetic fields in star formation is the ratio of the mass to the magnetic flux, M

  15. Magnetic fields around black holes

    NASA Astrophysics Data System (ADS)

    Garofalo, David A. G.

    Active Galactic Nuclei are the most powerful long-lived objects in the universe. They are thought to harbor supermassive black holes that range from 1 million solar masses to 1000 times that value and possibly greater. Theory and observation are converging on a model for these objects that involves the conversion of gravitational potential energy of accreting gas to radiation as well as Poynting flux produced by the interaction of the rotating spacetime and the electromagnetic fields originating in the ionized accretion flow. The presence of black holes in astrophysics is taking center stage, with the output from AGN in various forms such as winds and jets influencing the formation and evolution of the host galaxy. This dissertation addresses some of the basic unanswered questions that plague our current understanding of how rotating black holes interact with their surrounding magnetized accretion disks to produce the enormous observed energy. Two magnetic configurations are examined. The first involves magnetic fields connecting the black hole with the inner accretion disk and the other involves large scale magnetic fields threading the disk and the hole. We study the effects of the former type by establishing the consequences that magnetic torques between the black hole and the inner accretion disk have on the energy dissipation profile. We attempt a plausible explanation to the observed "Deep Minimum" state in the Seyfert galaxy MCG-6- 30-15. For the latter type of magnetic geometry, we study the effects of the strength of the magnetic field threading the black hole within the context of the cherished Blandford & Znajek mechanism for black hole spin energy extraction. We begin by addressing the problem in the non-relativistic regime where we find that the black hole-threading magnetic field is stronger for greater disk thickness, larger magnetic Prandtl number, and for a larger accretion disk. We then study the problem in full relativity where we show that our

  16. Development of aluminum-stabilized superconducting cables for the Mu2e detector solenoid

    SciTech Connect

    Lombardo, Vito; Buehler, M.; Lamm, M.; Page, T.; Curreli, S.; Fabbricatore, P.; Musenich, R.

    2016-06-01

    Here, the Mu2e experiment at Fermilab is designed to measure the rare process of direct muon-to-electron conversion in the field of a nucleus. The experiment comprises a system of three superconducting solenoids, which focus secondary muons from the production target and transport them to an aluminum stopping target, while minimizing the associated background. The Detector Solenoid (DS) is the last magnet in the transport line and its main functions are to provide a graded field in the region of the stopping target as well as a precision magnetic field in a volume large enough to house the tracker downstream of the stopping target. The Detector Solenoid coils are designed to be wound using NbTi Rutherford cables conformed in high purity aluminum for stabilization and then cold-worked for strength. Two types of Al-stabilized conductor are required to build the DS coils, one for the gradient section and one for the spectrometer section of the solenoid. The dimensions are optimized to generate the required field profile when the same current is transported in both conductors. The conductors contain NbTi Rutherford cables with 12 (DS1) and 8 (DS2) strands respectively and are manufactured by two different vendors. This paper describes the results of the manufacturing of production lengths of the Al-stabilized cables needed to build the Mu2e Detector Solenoid as well as the testing campaigns and main results. The main cable properties and results of electrical and mechanical tests are summarized and discussed for each stage of the cable development process. Results are compared to design values to show how the production cables satisfy all the design criteria starting from the NbTi wires to the Al-stabilized cables.

  17. Development of aluminum-stabilized superconducting cables for the Mu2e detector solenoid

    DOE PAGES

    Lombardo, Vito; Buehler, M.; Lamm, M.; ...

    2016-06-01

    Here, the Mu2e experiment at Fermilab is designed to measure the rare process of direct muon-to-electron conversion in the field of a nucleus. The experiment comprises a system of three superconducting solenoids, which focus secondary muons from the production target and transport them to an aluminum stopping target, while minimizing the associated background. The Detector Solenoid (DS) is the last magnet in the transport line and its main functions are to provide a graded field in the region of the stopping target as well as a precision magnetic field in a volume large enough to house the tracker downstream ofmore » the stopping target. The Detector Solenoid coils are designed to be wound using NbTi Rutherford cables conformed in high purity aluminum for stabilization and then cold-worked for strength. Two types of Al-stabilized conductor are required to build the DS coils, one for the gradient section and one for the spectrometer section of the solenoid. The dimensions are optimized to generate the required field profile when the same current is transported in both conductors. The conductors contain NbTi Rutherford cables with 12 (DS1) and 8 (DS2) strands respectively and are manufactured by two different vendors. This paper describes the results of the manufacturing of production lengths of the Al-stabilized cables needed to build the Mu2e Detector Solenoid as well as the testing campaigns and main results. The main cable properties and results of electrical and mechanical tests are summarized and discussed for each stage of the cable development process. Results are compared to design values to show how the production cables satisfy all the design criteria starting from the NbTi wires to the Al-stabilized cables.« less

  18. Majorana neutrinos and magnetic fields

    NASA Astrophysics Data System (ADS)

    Schechter, J.; Valle, J. W. F.

    1981-10-01

    It is stressed that if neutrinos are massive they are probably of "Majorana" type. This implies that their magnetic-moment form factor vanishes identically so that the previously discussed phenomenon of spin rotation in a magnetic field would not appear to take place. We point out that Majorana neutrinos can, however, have transition moments. This enables an inhomogeneous magnetic field to rotate both spin and "flavor" of a neutrino. In this case the spin rotation changes particle to antiparticle. The spin-flavor-rotation effect is worked out in detail. We also discuss the parametrization and calculation of the electromagnetic form factors of Majorana neutrinos. Our discussion takes into account the somewhat unusual quantum theory of massive Majorana particles.

  19. LIF Diagnostic for Measuring Beam-Transport Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Jones, T. G.; Hinshelwood, D. D.; Neri, J. M.; Ottinger, P. F.; Noonan, W. A.

    1997-11-01

    A novel, spatially-resolved diagnostic is being developed to measure magnetic fields associated with intense ion beam propagation through a low-pressure gas, as is envisioned for light ion-driven ICF. The diagnostic technique uses laser-induced fluorescence (LIF) spectroscopy, and can be varied to measure either small or large fields. Small fields, as expected in ballistic transport with solenoidal lens focusing using ~ 1 Torr gas, produce Zeeman shifts, Δ λ_Z, smaller than the transition linewidth, Δ λ. High sensitivity to measure these shifts is achieved by a variation on the Babcock technique.^1 Large fields, as expected in self-pinched transport using 1--100 mTorr gas, produce Δ λZ larger than Δ λ. These Δ λZ will be resolved using an etalon as a narrowband, high-throughput optical filter. Available results from benchtop experiments using calibrated B-fields for both the small- and large-field techniques, and progress in fielding this diagnostic on the Gamble-II accelerator for beam-transport studies will be presented. Work supported by DOE through Sandia National Laboratories. ^ National Research Council Research Associate. ^ Present address University of Maryland, College Park, MD. ^1 W.A. Noonan, et al., Rev. Sci. Instrum. 68, 1032 (1997).

  20. LIF Diagnostic for Measuring Beam-Transport Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Jones, T. G.; Noonan, W. A.; Ottinger, P. F.

    1996-11-01

    A novel, spatially-resolved diagnostic is being developed to measure magnetic fields associated with intense ion beam propagation through a low-pressure gas, as is envisioned for light ion-driven ICF. The diagnostic technique uses laser-induced fluorescence (LIF) spectroscopy, and can be varied to measure either small or large fields. Small fields, as expected in ballistic transport with solenoidal lens focusing using ~ 1 Torr gas, produce Zeeman shifts, Δ λ_Z, smaller than the transition linewidth, Δ λ. High sensitivity to measure these shifts is achieved by a variation on the Babcock technique.^1 Large fields, as expected in self-pinched transport using 10--100 mTorr gas, produce Δ λZ larger than Δ λ, which can be measured with a high-resolution spectrometer. Results of proof-of-principle experiments using calibrated B-fields for both the small- and large-field techniques will be presented. Progress in fielding this diagnostic on the Gamble-II accelerator for beam-transport studies will also be presented. This work is supported by DoE through Sandia National Laboratories. ^ NRC-NRL Research Associate. ^ Present address University of Maryland, College Park, MD. ^1 W.A. Noonan, et al., accepted for publication in Rev. Sci. Instrum.

  1. The magnetic design and field measurement of Fermilab collider detectors: CDF (the Collider Detector at Fermilab) and D0

    SciTech Connect

    Yamada, R.

    1990-02-01

    General magnetic characteristics of the CDF and D0 hadron collider detectors at Fermilab are described. The method and equipment for the field measurement for both detectors are described, and their field measurement data are presented. The magnetic field distribution inside the CDF solenoid magnet was measured extensively only at the boundaries, and the field values inside the volume were reconstructed. The effects due to the joints and the return conductor were measured and are discussed. The flux distribution inside the yokes and the fringing field of the D0 toroids were calculated and compared with measured data. A proposal to generate dipole magnetic field inside the D0 toroidal magnet is discussed. 9 refs., 6 figs.

  2. Separation of magnetic field lines

    SciTech Connect

    Boozer, Allen H.

    2012-11-15

    The field lines of magnetic fields that depend on three spatial coordinates are shown to have a fundamentally different behavior from those that depend on two coordinates. Unlike two-coordinate cases, a flux tube in a magnetic field that depends on all three spatial coordinates that has a circular cross section at one location along the tube characteristically has a highly distorted cross section at other locations. In an ideal evolution of a magnetic field, the current densities typically increase. Crudely stated, if the current densities increase by a factor {sigma}, the ratio of the long to the short distance across a cross section of a flux tube characteristically increases by e{sup 2{sigma}}, and the ratio of the longer distance to the initial radius increases as e{sup {sigma}}. Electron inertia prevents a plasma from isolating two magnetic field structures on a distance scale shorter than c/{omega}{sub pe}, which is about 10 cm in the solar corona, and reconnection must be triggered if {sigma} becomes sufficiently large. The radius of the sun, R{sub Circled-Dot-Operator }=7 Multiplication-Sign 10{sup 10}cm is about e{sup 23} times larger, so when {sigma} Greater-Than-Or-Equivalent-To 23, two lines separated by c/{omega}{sub pe} at one location can be separated by the full scale of any magnetic structures in the corona at another. The conditions for achieving a large exponentiation, {sigma}, are derived, and the importance of exponentiation is discussed.

  3. PYROTRON WITH TRANSLATIONAL CLOSURE FIELDS

    DOEpatents

    Hartwig, E.C.; Cummings, D.B.; Post, R.F.

    1962-01-01

    Circuit means is described for effecting inward transla- ' tory motion of the intensified terminal reflector field regions of a magnetic mirror plasma containment field with a simultaneous intensification of the over-all field configuration. The circuit includes a segmented magnetic field generating solenoid and sequentially actuated switch means to consecutively short-circuit the solenoid segments and place charged capacitor banks in shunt with the segments in an appropriate correlated sequence such that electrical energy is transferred inwardly between adjacent segments from the opposite ends of the solenoid. The resulting magnetic field is effective in both radially and axially adiabatically compressing a plasma in a reaction chamber disposed concentrically within the solenoid. In addition, one half of the circuit may be employed to unidirectionally accelerate plasma. (AEC)

  4. Magnetic fields in spiral galaxies

    NASA Astrophysics Data System (ADS)

    Krause, Marita

    2015-03-01

    The magnetic field structure in edge-on galaxies observed so far shows a plane-parallel magnetic field component in the disk of the galaxy and an X-shaped field in its halo. The plane-parallel field is thought to be the projected axisymmetric (ASS) disk field as observed in face-on galaxies. Some galaxies addionionally exhibit strong vertical magnetic fields in the halo right above and below the central region of the disk. The mean-field dynamo theory in the disk cannot explain these observed fields without the action of a wind, which also probably plays an important role to keep the vertical scale heights constant in galaxies of different Hubble types and star formation activities, as has been observed in the radio continuum: At λ6 cm the vertical scale heights of the thin disk and the thick disk/halo in a sample of five edge-on galaxies are similar with a mean value of 300 +/- 50 pc for the thin disk and 1.8 +/- 0.2 kpc for the thick disk (a table and references are given in Krause 2011) with our sample including the brightest halo observed so far, NGC 253, with strong star formation, as well as one of the weakest halos, NGC 4565, with weak star formation. If synchrotron emission is the dominant loss process of the relativistic electrons the outer shape of the radio emission should be dumbbell-like as has been observed in several edge-on galaxies like e.g. NGC 253 (Heesen et al. 2009) and NGC 4565. As the synchrotron lifetime t syn at a single frequency is proportional to the total magnetic field strength B t -1.5, a cosmic ray bulk speed (velocity of a galactic wind) can be defined as v CR = h CR /t syn = 2 h z /t syn , where h CR and h z are the scale heights of the cosmic rays and the observed radio emission at this freqnency. Similar observed radio scale heights imply a self regulation mechanism between the galactic wind velocity, the total magnetic field strength and the star formation rate SFR in the disk: v CR ~ B t 1.5 ~ SFR ~ 0.5 (Niklas & Beck 1997).

  5. The DARHT-II-DC Final Focus Solenoid

    SciTech Connect

    Paul, A.C.

    2000-03-06

    The baseline DARHT2 external beam uses a pulsed solenoid final focus lens. The design of this lens was presented at TOS2 and has been considered as the final focus lens in all of the Livermore beamlines for DARHT2. In this note, we consider a new alternative DC final focus solenoid. A crude comparison between the parameters of these two designs is given in table 1. The small spot size required by the radiography and the small drift distance available between the last magnetic focusing element and the final focus solenoid imposed by the close proximity between the DARHT 2 building and the DARHT 1 axis, implies a short focal length solenoid. This in turn requires that the final focus solenoid mount inside the re-entrant cavity of the containment vessel in order to accommodate the 0.9 meter conjugate: figure 1. The ID of this cavity is 13.88 inches (35.25 cm).

  6. Magnetic fields in the sun

    NASA Technical Reports Server (NTRS)

    Mullan, D. J.

    1974-01-01

    The observed properties of solar magnetic fields are reviewed, with particular reference to the complexities imposed on the field by motions of the highly conducting gas. Turbulent interactions between gas and field lead to heating or cooling of the gas according to whether the field energy density is less or greater than the maximum kinetic energy density in the convection zone. The field strength above which cooling sets in is 700 gauss. A weak solar dipole field may be primeval, but dynamo action is also important in generating new flux. The dynamo is probably not confined to the convection zone, but extends throughout most of the volume of the sun. Planetary tides appear to play a role in driving the dynamo.

  7. The magnetic field of Jupiter

    NASA Technical Reports Server (NTRS)

    Acuna, M. H.; Ness, N. F.

    1976-01-01

    The paper is concerned mainly with the intrinsic planetary field which dominates the inner magnetosphere up to a distance of 10 to 12 Jovian radii where other phenomena, such as ring currents and diamagnetic effects of trapped charged particles, become significant. The main magnetic field of Jupiter as determined by in-situ observations by Pioner 10 and 11 is found to be relatively more complex than a simple offset tilted dipole. Deviations from a simple dipole geometry lead to distortions of the charged particle L shells and warping of the magnetic equator. Enhanced absorption effects associated with Io and Amalthea are predicted. The results are consistent with the conclusions derived from extensive radio observations at decimetric and decametric wavelengths for the planetary field.

  8. Circularly Inclined Solenoid Channel for 6D Ionization Cooling of Muons

    SciTech Connect

    Alexahin, Y.; /Fermilab

    2009-05-01

    Ionization cooling is essential for realization of Muon Collider, muons beam based neutrino factories and other experiments involving muons. The simplest structure - absorber(s) immersed in alternating solenoidal magnetic field - provides only transverse cooling since the longitudinal motion in the most suitable momentum range (2-300MeV/c) is naturally anti-damped. To overcome this difficulty it is proposed to periodically tilt solenoids so that a rotating transverse magnetic field was created. By choosing the phase advance per period above a multiple of 2{pi} it is possible to ensure that muons with higher momentum make a longer path in the absorber (whether distributed or localized) thus providing longitudinal damping. Basic theory of such channel and results of tracking simulations are presented.

  9. Design and fabrication of layer-wound YBCO solenoids

    NASA Astrophysics Data System (ADS)

    Uglietti, D.; Choi, S.; Kiyoshi, T.

    2010-11-01

    Rare Earth based coated conductors are very promising conductors for the construction of high field solenoids. Development of coil winding technique was started at the Tsukuba Magnet Laboratory: coils of various sizes (from 18 mm to 220 mm of an inner diameter) have been fabricated by layer-winding without impregnation in order to test the mechanical and superconducting properties. In the thin 220 mm diameter coil the Hoop stress reached over 500 MPa at 130 A in 14 T background field, without degradation of the superconducting properties. In the small diameter coils (18 mm of inner diameter) the tape was insulated using enamel to minimize the cross section and to enhance the coil current density. The highest field generated was 2.1 T in a background field of 18 T (total field was 20.1 T) at 4.2 K and the coil current density was 240 A/mm2.

  10. Oxide superconductors under magnetic field

    NASA Technical Reports Server (NTRS)

    Kitazawa, K.

    1990-01-01

    One of the current most serious problems for the oxide superconductors from the standpoint of practical application is the various novel features derived mainly from their extremely short coherence. In particular, the coherence length so far observed in the cuprate superconductors is in the range of 0.1 nm perpendicular to the CuO2 plane. This seems to be creating most of the difficulties in the device fabrication and in the performance under the magnetic field. Some of the superconducting properties under the magnetic field will be discussed in terms of the short coherence length. A model will be presented based on the gradual strengthening of the pinning force with decrease in temperature and the weak coupling at the grain boundaries. Secondly, the broadening of the superconducting transition under the magnetic field is discussed. This is observed significantly only when the field is applied perpendicular to the basal plane and the relative orientation of the current to the field is insignificant in determining the extent of the broadening. Besides, the change in the strength of the pinning force does not affect the width of the broadening. From these observations discussions will be made on a model based on the giant fluctuation. Based on this model, it is predicted that the coherence length along the c-axis will be the single most important material parameter to determine the performance of the superconductor under a strong magnetic field. It seems that BYCO is superior in this regard to Bi- or Tl-systems as far as the performance at 77 K is considered, although another material with the coherence length slightly longer along the c-axis is still highly desired.

  11. Oxide superconductors under magnetic field

    NASA Technical Reports Server (NTRS)

    Kitazawa, K.

    1991-01-01

    One of the current most serious problems for the oxide superconductors from the standpoint of practical application is the various novel features derived mainly from their extremely short coherence. In particular, the coherence length so far observed in the cuprate superconductors is in the range of 0.1 nm perpendicular to the CuO2 plane. This seems to be creating most of the difficulties in the device fabrication and in the performance under the magnetic field. Some of the superconducting properties under the magnetic field will be discussed in terms of the short coherence length. A model will be presented based on the gradual strengthening of the pinning force with decrease in temperature and the weak coupling at the grain boundaries. Secondly, the broadening of the superconducting transition under the magnetic field is discussed. This is observed significantly only when the field is applied perpendicular to the basal plane and the relative orientation of the current to the field is insignificant in determining the extent of broadening. Besides, the change in the strength of the pinning force does not affect the width of the broadening. From these observations discussions will be made on a model based on the giant fluctuation. Based on this model, it is predicted that the coherence length along the c-axis will be the single most important material parameter to determine the performance of the superconductor under a strong magnetic field. It seems that BYCO is superior in this regard to Bi- or Tl-systems as far as the performance at 77 K is considered, although another material with the coherence length slightly longer along the c-axis is still highly desired.

  12. Magnetic Fields on the National Ignition Facility (MagNIF)

    SciTech Connect

    Mason, D.; Folta, J.

    2016-08-12

    A magnetized target capability on the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) has been investigated. Stakeholders’ needs and project feasibility analysis were considered in order to down-select from a wide variety of different potential magnetic field magnitudes and volumes. From the large range of different target platforms, laser configurations, and diagnostics configurations of interest to the stakeholders, the gas-pipe platform has been selected for the first round of magnetized target experiments. Gas pipe targets are routinely shot on the NIF and provide unique value for external collaborators. High-level project goals have been established including an experimentally relevant 20Tesla magnetic field magnitude. The field will be achieved using pulsed power-driven coils. A system architecture has been proposed. The pulsed power drive system will be located in the NIF target bay. This decision provides improved maintainability and mitigates equipment safety risks associated with explosive failure of the drive capacitor. High-level and first-level subsystem requirements have been established. Requirements have been included for two distinct coil designs – full solenoid and quasi-Helmholtz. A Failure Modes and Effects Analysis (FMEA) has been performed and documented. Additional requirements have been derived from the mitigations included in the FMEA document. A project plan is proposed. The plan includes a first phase of electromagnetic simulations to assess whether the design will meet performance requirements, then a second phase of risk mitigation projects to address the areas of highest technical risk. The duration from project kickoff to the first magnetized target shot is approximately 29 months.

  13. Toroidal metrics: gravitational solenoids and static shells

    NASA Astrophysics Data System (ADS)

    Lynden-Bell, Donald; Katz, Joseph

    2012-06-01

    In electromagnetism a current along a wire tightly wound on a torus makes a solenoid whose magnetic field is confined within the torus. In Einstein's gravity we give a corresponding solution in which a current of matter moves up on the inside of a toroidal shell and down on the outside, rolling around the torus by the short way. The metric is static outside the torus but stationary inside with the gravomagnetic field confined inside the torus, running around it by the long way. This exact solution of Einstein's equations is found by fitting Bonnor's solution for the metric of a light beam, which gives the required toroidal gravomagnetic field inside the torus, to the general Weyl static external metric in toroidal coordinates, which we develop. We deduce the matter tensor on the torus and find when it obeys the energy conditions. We also give the equipotential shells that generate the simple Bach-Weyl metric externally and find which shells obey the energy conditions.

  14. 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.

  15. 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.

  16. The HMI Magnetic Field Pipeline

    NASA Astrophysics Data System (ADS)

    Hoeksema, Jon Todd; Liu, Y.; Schou, J.; Scherrer, P.; HMI Science Team

    2009-05-01

    The Helioseismic and Magnetic Imager (HMI) will provide frequent full-disk magnetic field data after launch of the Solar Dynamics Observatory (SDO), currently scheduled for fall 2009. 16 megapixel line-of-sight magnetograms (Blos) will be recorded every 45 seconds. A full set of polarized filtergrams needed to determine the vector magnetic field requires 90 seconds. Quick-look data will be available within a few minutes of observation. Quick-look space weather and browse products must have identified users, and the list currently includes full disk magnetograms, feature identification and movies, 12-minute disambiguated vector fields in active region patches, time evolution of AR indices, synoptic synchronic frames, potential and MHD model results, and 1 AU predictions. A more complete set of definitive science data products will be offered about a day later and come in three types. "Pipeline” products, such as full disk vector magnetograms, will be computed for all data on an appropriate cadence. A larger menu of "On Demand” products, such as Non-Linear Force Free Field snapshots of an evolving active region, will be produced whenever a user wants them. Less commonly needed "On Request” products that require significant project resources, such as a high resolution MHD simulation of the global corona, will be created subject to availability of resources. Further information can be found at the SDO Joint Science Operations Center web page, jsoc.stanford.edu

  17. Low field magnetic resonance imaging of laser-polarized noble gases

    NASA Astrophysics Data System (ADS)

    Wong, G. P.; Tseng, C.-H.; Mair, R. W.; Hoffmann, D.; Walsworth, R. L.; Pomeroy, V. R.; Hersman, F. W.; Cory, D. G.

    1998-05-01

    We have demonstrated low field magnetic resonance imaging (MRI) using laser-polarized noble gases. Conventional MRI requires large magnetic fields ( ~ 1 tesla) to create an observable nuclear magnetization via thermal polarization of the nuclear spins (e.g. ^1H spins in water). Alternatively, optical pumping techniques using lasers can create large nuclear spin polarizations (> 10%) in the spin-1/2 noble gases, ^3He and ^129Xe. This laser polarization technique greatly enhances the nuclear magnetic resonance (NMR) detection sensitivity of the noble gases, enabling fast, gas-phase MRI at low magnetic fields (< 100 gauss). Using a simple, wire-wound solenoid, we made images at 21 gauss of laser-polarized ^3He in a variety of samples. Each image took approximately 15 seconds to acquire, with a typical resolution of 1 mm^2. In contrast, a water (^1H) image at the same field with comparable resolution would require ~ 2 months of signal averaging. We also made images that demonstrate the efficacy of low field noble gas MRI for materials that are problematic at high magnetic fields: (i) paramagnetic materials, whose magnetic susceptibilities induce image-distorting field gradients; and (ii) conductors, which prevent high field imaging because of Faraday (i.e. RF) shielding.

  18. Magnetic field sensor based on the Ampere's force using dual-polarization DBR fiber laser

    NASA Astrophysics Data System (ADS)

    Yao, Shuang; Zhang, Yang; Guan, Baiou

    2015-08-01

    A novel magnetic field sensor using distributed Bragg reflector (DBR) fiber laser by Ampere's force effect is proposed and experimentally demonstrated. The key sensing element, that is the dual-polarization DBR fiber laser, is fixed on the middle part of two copper plates which carry the current. Ampere's force is applied onto the coppers due to an external magnetic field generated by a DC solenoid. Thus, the lateral force from the coppers is converted to a corresponding beat frequency signal shift produced by the DBR laser. The electric current sensing is also realized by the same configuration and same principle simultaneously in an intuitive manner. Good agreement between the theory calculation and the experimental results is obtained, which shows a good linearity. This sensor's sensitivity to the magnetic field and to the electric current finally reaches ~258.92 kHz/mT and ~1.08727 MHz/A, respectively.

  19. Simulation investigation of a Ku-band radial line oscillator operating at low guiding magnetic field

    SciTech Connect

    Dang, Fangchao Zhang, Xiaoping; Zhong, Huihuang; Li, Yangmei; Qi, Zumin

    2014-06-15

    A novel radial line oscillator operating at Ku-band with low guiding magnetic field is proposed in this paper. By using an oversized radial structure, the power handling capacity is enhanced significantly. Based on the small-signal theory, the π/2 mode in radial TM{sub 01} mode is selected as the working mode. Furthermore, a radial uniform guiding magnetic field, made up of four solenoids, is designed. As indicated in 2.5-dimensional fully electromagnetic particle-in-cell simulation, high power microwaves with a power of 2.2 GW and a frequency of 14.25 GHz are generated with over 40% efficiency when the electron beam voltage is 300 kV, the beam current 18 kA, and the guiding magnetic field is only 0.6 T. There is no angular non-asymmetric mode discovered in three-dimensional simulation.

  20. Simulation investigation of a Ku-band radial line oscillator operating at low guiding magnetic field

    NASA Astrophysics Data System (ADS)

    Dang, Fangchao; Zhang, Xiaoping; Zhong, Huihuang; Li, Yangmei; Qi, Zumin

    2014-06-01

    A novel radial line oscillator operating at Ku-band with low guiding magnetic field is proposed in this paper. By using an oversized radial structure, the power handling capacity is enhanced significantly. Based on the small-signal theory, the π/2 mode in radial TM01 mode is selected as the working mode. Furthermore, a radial uniform guiding magnetic field, made up of four solenoids, is designed. As indicated in 2.5-dimensional fully electromagnetic particle-in-cell simulation, high power microwaves with a power of 2.2 GW and a frequency of 14.25 GHz are generated with over 40% efficiency when the electron beam voltage is 300 kV, the beam current 18 kA, and the guiding magnetic field is only 0.6 T. There is no angular non-asymmetric mode discovered in three-dimensional simulation.

  1. The Results of Recent MICE Superconducting Spectrometer Solenoid Test

    SciTech Connect

    Green, Michael A; Virostek, Steve P.; Zisman, Michael S.

    2010-10-15

    The MICE spectrometer solenoid magnets will be the first magnets to be installed within the MICE cooling channel. The MICE spectrometer solenoids may be the largest magnets that have been cooled using small two stage coolers. During the previous test of this magnet, the cooler first stage temperatures were too high. The causes of some of the extra first stage heat load has been identified and corrected. The rebuilt magnet had a single stage GM cooler in addition to the three pulse tube coolers. The added cooler reduces the temperature of the top of the HTS leads, the shield and of the first stage of the pulse tube coolers.

  2. Optimum coil shape for a given volume of conductor to obtain maximum central field in an air core solenoid

    SciTech Connect

    Hernandez, P.

    1995-02-01

    This paper is an expansion of engineering notes prepared in 1961 to address the question of how to wind circular coils so as to obtain the maximum axial field with the minimum volume of conductor. At the time this was a germain question because of the advent of superconducting wires which were in very limited supply, and the rapid push for generation of very high fields, with little concern for uniformity.

  3. Effect of Magnetic Field Gradient on Plasma Detachment Induced by Breaking of Adiabatic Plasma Expansion

    NASA Astrophysics Data System (ADS)

    Chung, K. S.; Kim, June Young; Chung, Kyoung-Jae; Hwang, Y. S.

    2016-10-01

    A magnetic field gradient that is a variation in the magnetic field around the ion flow has been investigated as a primary parameter for ion detachment in the magnetic nozzle geometries. Some scale lengths of magnetic field are controlled by two solenoid coils outside the diffusion chamber of a ECR-driven linear plasma device. The axial and radial profiles of the plasma potential and electron temperature are measured by a Langmuir probe array for the various magnetic field configurations in the downstream. The local adiabaticity, strong constant magnetic moment, is satisfied with a linear relationship between the change in effective electron temperature and the change in plasma potential in the low magnetic field gradient. Whereas, with an increasing non-homogeneity of the magnetic field in the direction of the flow, the breaking of adiabatic plasma expansion is identified to measure the nonlinear process which is the variation for an adiabatic exponent. Such the loss of adiabaticity is also explained in terms of non-adiabaticity parameter i.e. degree of demagnetization. This research was supported by National R&D Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (Nos. 2014M1A7A1A02030165 and 2014M1A7A1A03045367).

  4. Explaining Mercury's peculiar magnetic field

    NASA Astrophysics Data System (ADS)

    Wicht, Johannes; Cao, Hao; Heyner, Daniel; Dietrich, Wieland; Christensen, Ulrich R.

    2014-05-01

    MESSENGER magnetometer data revealed that Mercury's magnetic field is not only particularly weak but also has a peculiar geometry. The MESSENGER team finds that the location of the magnetic equator always lies significantly north of the geographic equator, is largely independent of the distance to the planet, and also varies only weakly with longitude. The field is best described by an axial dipole that is offset to the north by about 20% of the planetary radius. In terms of classical Gauss coefficients, this translates into a low axial dipole component of g10= -190 nT but a relatively large axial quadrupole contribution that amounts to roughly 40% of this value. The axial octupole is also sizable while higher harmonic contributions are much weaker. Very remarkable is also the fact that the equatorial dipole contribution is very small, consistent with a dipole tilt below 0.8 degree, and this is also true for the other non-axisymmetic field contributions. We analyze several numerical dynamos concerning their capability of explaining Mercury's magnetic field. Classical schemes geared to model the geomagnetic field typically show a much weaker quadrupole component and thus a smaller offset. The onset only becomes larger when the dynamo operates in the multipolar regime at higher Rayleigh numbers. However, since the more complex dynamics generally promotes all higher multipole contributions the location of the magnetic equator varies strongly with longitude and distance to the planet. The situation improves when introducing a stably stratified outer layer in the dynamo region, representing either a rigid FeS layer or a sub-adiabatic core-mantle boundary heat flux. This layer filters out the higher harmonic contributions and the field not only becomes sufficiently weak but also assumes a Mercury like offset geometry during a few percent of the simulation time. To increase the likelihood for the offset configuration, the north-south symmetry must be permanently broken

  5. Magnetic Fields in Massive Filaments

    NASA Astrophysics Data System (ADS)

    Pillai, Thushara

    Magnetic fields pervade galaxies, shaping them from the largest scales to the smallest star forming scales. A firm understanding of their role is crucial to our understanding of the physics of ISM. A dominant phase of the ISM that has received considerable attention is that of filaments which are ubiquitous and dominate the mass reservoir in molecular clouds. Enormous progress has been made recently towards understanding filament properties. The next major step should be to understand the role of magnetic fields in filaments. We propose to take advantage of HAWC+ dust emission polarimeter now available on SOFIA to launch a pilot polarization study towards three major classes of filaments: (i) Pristine (ii) Hub-Filament systems and (iii) Perturbed. HAWC+ will trace the connection between the star forming cores and the filaments enveloping them. By covering a vast range in parameter space from quiescent to active filaments, we will be constraining the initial conditions prior to star formation, during star formation and after star formation (feedback from newly formed stars on their parent clouds.) The interpretation of observations will be supported by extensive custom-made numerical simulations of magnetized clouds and subsequent dust radiative transfer with various grain alignment mechanisms, as provided by collaborators. Combined, these observations will provide the first panoramic view of the magnetized nature of massive filaments in the ISM.

  6. Magnetic Fields in Massive Filaments

    NASA Astrophysics Data System (ADS)

    Pillai, G. S. Thushara

    2015-10-01

    Magnetic fields pervade galaxies, shaping them from the largest scales to the smallest star forming scales. A firm understanding of their role is crucial to our understanding of the physics of ISM. A dominant phase of the ISM that has received considerable attention is that of filaments which are ubiquitous and dominate the mass reservoir in molecular clouds. Enormous progress has been made recently towards understanding filament properties. The next major step should be to understand the role of magnetic fields in filaments. We propose to take advantage of HAWC+ dust emission polarimeter now available on SOFIA to launch a pilot polarization study towards three major classes of filaments: (i) Pristine (ii) Hub-Filament systems and (iii) Perturbed. HAWC+ will trace the connection between the star forming cores and the filaments enveloping them. By covering a vast range in parameter space from quiescent to active filaments, we will be constraining the initial conditions prior to star formation, during star formation and after star formation (feedback from newly formed stars on their parent clouds.) The interpretation of observations will be supported by extensive custom--made numerical simulations of magnetized clouds and subsequent dust radiative transfer with various grain alignment mechanisms, as provided by collaborators. Combined, these observations will provide the first panoramic view of the magnetized nature of massive filaments in the ISM.

  7. Distorted orbit due to field errors and particle trajectories in combined undulator and axial magnetic field

    SciTech Connect

    Papadichev, V.A.

    1995-12-31

    Undulator and solenoid field errors cause electron trajectory deviation from the ideal orbit. Even small errors can result in a large lower frequency excursion from the undulator axis of a distorted orbit and of betatron oscillations performed now around it, especially near resonant conditions. Numerical calculation of a trajectory step by step requires large computing time and treats only particular cases, thus lacking generality. Theoretical treatment is traditionally based on random distribution of field errors, which allows a rather general approach, but is not convenient for practical purposes. In contrast, analytical treatment shows explicitly how distorted orbit and betatron oscillation amplitude depend on field parameters and errors and indicates how to eliminate these distortions. An analytical solution of the equations of motion can be found by expanding field errors and distorted orbit in Fourier series as was done earlier for the simplest case of a plane undulator without axial magnetic field. The same method is applied now to the more general case of combined generlized undulator and axial magnetic fields. The undulator field is a superposition of the fields of two plane undulators with mutually orthogonal fields and an arbitrary axial shift of the second undulator relative to the first. Beam space-charge forces and external linear focusing are taken into account. The particle trajectory is a superposition of ideal and distorted orbits with cyclotron gyration and slow drift gyration in the axial magnetic field caused by a balance of focusing and defocusing forces. The amplitudes of these gyrations depend on transverse coordinate and velocity at injection and can nearly double the total deviation of an electron from the undulator axis even after an adiabatic undulator entry. If the wavenumber of any Fourier harmonic is close to the wavenumbers of cyclotron or drift gyrations, a resonant increase of orbit distortion occurs.

  8. Field errors in superconducting magnets

    SciTech Connect

    Barton, M. Q.

    1982-01-01

    The mission of this workshop is a discussion of the techniques for tracking particles through arbitrary accelerator field configurations to look for dynamical effects that are suggested by various theoretical models but are not amenable to detailed analysis. A major motivation for this type of study is that many of our accelerator projects are based on the use of superconducting magnets which have field imperfections that are larger and of a more complex nature than those of conventional magnets. Questions such as resonances, uncorrectable closed orbit effects, coupling between planes, and diffusion mechanisms all assume new importance. Since, simultaneously, we are trying to do sophisticated beam manipulations such as stacking, high current accelerator, long life storage, and low loss extraction, we clearly need efficient and accurate tracking programs to proceed with confidence.

  9. Introducing Electromagnetic Field Momentum

    ERIC Educational Resources Information Center

    Hu, Ben Yu-Kuang

    2012-01-01

    I describe an elementary way of introducing electromagnetic field momentum. By considering a system of a long solenoid and line charge, the dependence of the field momentum on the electric and magnetic fields can be deduced. I obtain the electromagnetic angular momentum for a point charge and magnetic monopole pair partially through dimensional…

  10. Studies of the Impact of Magnetic Field Uncertainties on Physics Parameters of the Mu2e Experiment

    SciTech Connect

    Bradascio, Federica

    2016-01-01

    The Mu2e experiment at Fermilab will search for a signature of charged lepton flavor violation, an effect prohibitively too small to be observed within the Standard Model of particle physics. Therefore, its observation is a signal of new physics. The signature that Mu2e will search for is the ratio of the rate of neutrinoless coherent conversion of muons into electrons in the field of a nucleus, relative to the muon capture rate by the nucleus. The conversion process is an example of charged lepton flavor violation. This experiment aims at a sensitivity of four orders of magnitude higher than previous related experiments. The desired sensitivity implies highly demanding requirements of accuracy in the design and conduct of the experiment. It is therefore important to investigate the tolerance of the experiment to instrumental uncertainties and provide specifications that the design and construction must meet. This is the core of the work reported in this thesis. The design of the experiment is based on three superconducting solenoid magnets. The most important uncertainties in the magnetic field of the solenoids can arise from misalignments of the Transport Solenoid, which transfers the beam from the muon production area to the detector area and eliminates beam-originating backgrounds. In this thesis, the field uncertainties induced by possible misalignments and their impact on the physics parameters of the experiment are examined. The physics parameters include the muon and pion stopping rates and the scattering of beam electrons off the capture target, which determine the signal, intrinsic background and late-arriving background yields, respectively. Additionally, a possible test of the Transport Solenoid alignment with low momentum electrons is examined, as an alternative option to measure its field with conventional probes, which is technically difficult due to mechanical interference. Misalignments of the Transport Solenoid were simulated using standard

  11. Comparing Magnetic Fields on Earth and Mars

    NASA Video Gallery

    This animation compares the magnetic fields on Earth and Mars. The Earth has a large-scale planetary magnetic field that can protect it from space weather and other hazards. Mars, on the other hand...

  12. Field quality aspects of CBA superconducting magnets

    SciTech Connect

    Kahn, S.; Engelmann, R.; Fernow, R.; Greene, A.F.; Herrera, J.; Kirk, H.; Skaritka, J.; Wanderer, P.; Willen, E.

    1983-01-01

    A series of superconducting dipole magnets for the BNL Colliding Beam Accelerator which were manufactured to have the proper field quality characteristics has been tested. This report presents the analysis of the field harmonics of these magnets.

  13. Measurements of Solar Vector Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Hagyard, M. J. (Editor)

    1985-01-01

    Various aspects of the measurement of solar magnetic fields are presented. The four major subdivisions of the study are: (1) theoretical understanding of solar vector magnetic fields; (3) techniques for interpretation of observational data; and (4) techniques for data display.

  14. Magnetic Helicity Estimations in Models and Observations of the Solar Magnetic Field. Part I: Finite Volume Methods

    NASA Astrophysics Data System (ADS)

    Valori, Gherardo; Pariat, Etienne; Anfinogentov, Sergey; Chen, Feng; Georgoulis, Manolis K.; Guo, Yang; Liu, Yang; Moraitis, Kostas; Thalmann, Julia K.; Yang, Shangbin

    2016-11-01

    Magnetic helicity is a conserved quantity of ideal magneto-hydrodynamics characterized by an inverse turbulent cascade. Accordingly, it is often invoked as one of the basic physical quantities driving the generation and structuring of magnetic fields in a variety of astrophysical and laboratory plasmas. We provide here the first systematic comparison of six existing methods for the estimation of the helicity of magnetic fields known in a finite volume. All such methods are reviewed, benchmarked, and compared with each other, and specifically tested for accuracy and sensitivity to errors. To that purpose, we consider four groups of numerical tests, ranging from solutions of the three-dimensional, force-free equilibrium, to magneto-hydrodynamical numerical simulations. Almost all methods are found to produce the same value of magnetic helicity within few percent in all tests. In the more solar-relevant and realistic of the tests employed here, the simulation of an eruptive flux rope, the spread in the computed values obtained by all but one method is only 3 %, indicating the reliability and mutual consistency of such methods in appropriate parameter ranges. However, methods show differences in the sensitivity to numerical resolution and to errors in the solenoidal property of the input fields. In addition to finite volume methods, we also briefly discuss a method that estimates helicity from the field lines' twist, and one that exploits the field's value at one boundary and a coronal minimal connectivity instead of a pre-defined three-dimensional magnetic-field solution.

  15. Minireview: Biological effects of magnetic fields

    SciTech Connect

    Villa, M.; Mustarelli, P. ); Caprotti, M. )

    1991-01-01

    The literature about the biological effects of magnetic fields is reviewed. The authors begin by discussing the weak and/or time variable fields, responsible for subtle changes in the circadian rhythms of superior animals, which are believed to be induced by same sort of resonant mechanism. The safety issues related with the strong magnetic fields and gradients generated by clinical NMR magnets are then considered. The last portion summarizes the debate about the biological effects of strong and uniform magnetic fields.

  16. Generation of 1.5-kW, 1-THz coherent radiation from a gyrotron with a pulsed magnetic field.

    PubMed

    Glyavin, M Yu; Luchinin, A G; Golubiatnikov, G Yu

    2008-01-11

    To cover a so-called terahertz gap in available sources of coherent electromagnetic radiation, the gyrotron with a pulsed solenoid producing up to a 40 T magnetic field has been designed, manufactured, and tested. At a 38.5 T magnetic field, the gyrotron generated coherent radiation at 1.022 THz frequency in 50 musec pulses. The microwave power and energy per pulse were about 1.5 kW and 75 mJ, respectively. Details of the gyrotron design, manufacturing, operation and measurements of output radiation are given.

  17. The Superconducting Magnets of the ILC Beam Delivery System

    SciTech Connect

    Parker, B.; Anerella, M.; Escallier, J.; He, P.; Jain, A.; Marone, A.; Nosochkov, Y.; Seryi, Andrei; /SLAC

    2007-09-28

    The ILC Beam Delivery System (BDS) uses a variety of superconducting magnets to maximize luminosity and minimize background. Compact final focus quadrupoles with multifunction correction coils focus incoming beams to few nanometer spot sizes while focusing outgoing disrupted beams into a separate extraction beam line. Anti-solenoids mitigate effects from overlapping focusing and the detector solenoid field. Far from the interaction point (IP) strong octupoles help minimize IP backgrounds. A low-field but very large aperture dipole is integrated with the detector solenoid to reduce backgrounds from beamstrahlung pairs generated at the IP. Physics requirements and magnetic design solutions for the BDS superconducting magnets are reviewed in this paper.

  18. Magnetic field effects on mitochondrion-activity-related optical properties in slime mold and bone forming cells.

    PubMed

    Mizukawa, Yuri; Iwasaka, Masakazu

    2013-01-01

    In the present study, a cellular level response of Cyto-aa3 oxidation was investigated in real time under both time-varying and strong static magnetic fields of 5 T. Two kinds of cells, a slime mold, Physarum polycephalum, and bone forming cells, MC-3T3-E1, were used for the experiments. The oxidation level of the Cyto-aa3 was calculated by optical absorptions at 690 nm, 780 nm and 830 nm. The sample, fiber-optics and an additional optical fiber for light stimulation were set in a solenoidal coil or the bore of a 5-T superconducting magnet. The solenoidal coil for time-varying magnetic fields produced sinusoidal magnetic fields of 6 mT. The slime mold showed a periodic change in Cyto-aa3 oxidation, and the oxidation-reduction cycle of Cyto-aa3 was apparently changed when visible-light irradiated the slime mold. Similarly to the case with light, time-varying magnetic stimulations changed the oxidation-reduction cycle during and after the stimulation for 10 minutes. The same phenomena were observed in the MC-3T3-E1 cell assembly, although their cycle rhythm was comparatively random. Finally, magnetic field exposure of up to 5 T exhibited a distinct suppression of Cyto-aa3 oscillation in the bone forming cells. Exposure up to 5 T was repeated five times, and the change in Cyto-aa3 oxidation reproducibly occurred.

  19. Bats respond to very weak magnetic fields.

    PubMed

    Tian, Lan-Xiang; Pan, Yong-Xin; Metzner, Walter; Zhang, Jin-Shuo; Zhang, Bing-Fang

    2015-01-01

    How animals, including mammals, can respond to and utilize the direction and intensity of the Earth's magnetic field for orientation and navigation is contentious. In this study, we experimentally tested whether the Chinese Noctule, Nyctalus plancyi (Vespertilionidae) can sense magnetic field strengths that were even lower than those of the present-day geomagnetic field. Such field strengths occurred during geomagnetic excursions or polarity reversals and thus may have played an important role in the evolution of a magnetic sense. We found that in a present-day local geomagnetic field, the bats showed a clear preference for positioning themselves at the magnetic north. As the field intensity decreased to only 1/5th of the natural intensity (i.e., 10 μT; the lowest field strength tested here), the bats still responded by positioning themselves at the magnetic north. When the field polarity was artificially reversed, the bats still preferred the new magnetic north, even at the lowest field strength tested (10 μT), despite the fact that the artificial field orientation was opposite to the natural geomagnetic field (P<0.05). Hence, N. plancyi is able to detect the direction of a magnetic field even at 1/5th of the present-day field strength. This high sensitivity to magnetic fields may explain how magnetic orientation could have evolved in bats even as the Earth's magnetic field strength varied and the polarity reversed tens of times over the past fifty million years.

  20. Design of 95 GHz gyrotron based on continuous operation copper solenoid with water cooling

    SciTech Connect

    Borodin, Dmitri; Ben-Moshe, Roey; Einat, Moshe

    2014-07-15

    The design work for 2nd harmonic 95 GHz, 50 kW gyrotron based on continuous operation copper solenoid is presented. Thermionic magnetron injection gun specifications were calculated according to the linear trade off equation, and simulated with CST program. Numerical code is used for cavity design using the non-uniform string equation as well as particle motion in the “cold” cavity field. The mode TE02 with low Ohmic losses in the cavity walls was chosen as the operating mode. The Solenoid is designed to induce magnetic field of 1.8 T over a length of 40 mm in the interaction region with homogeneity of ±0.34%. The solenoid has six concentric cylindrical segments (and two correction segments) of copper foil windings separated by water channels for cooling. The predicted temperature in continuous operation is below 93 °C. The parameters of the design together with simulation results of the electromagnetic cavity field, magnetic field, electron trajectories, and thermal analyses are presented.

  1. Design of 95 GHz gyrotron based on continuous operation copper solenoid with water cooling

    NASA Astrophysics Data System (ADS)

    Borodin, Dmitri; Ben-Moshe, Roey; Einat, Moshe

    2014-07-01

    The design work for 2nd harmonic 95 GHz, 50 kW gyrotron based on continuous operation copper solenoid is presented. Thermionic magnetron injection gun specifications were calculated according to the linear trade off equation, and simulated with CST program. Numerical code is used for cavity design using the non-uniform string equation as well as particle motion in the "cold" cavity field. The mode TE02 with low Ohmic losses in the cavity walls was chosen as the operating mode. The Solenoid is designed to induce magnetic field of 1.8 T over a length of 40 mm in the interaction region with homogeneity of ±0.34%. The solenoid has six concentric cylindrical segments (and two correction segments) of copper foil windings separated by water channels for cooling. The predicted temperature in continuous operation is below 93 °C. The parameters of the design together with simulation results of the electromagnetic cavity field, magnetic field, electron trajectories, and thermal analyses are presented.

  2. An investigation of magnetic field effects on plume density and temperature profiles of an applied-field MPD thruster

    NASA Technical Reports Server (NTRS)

    Bullock, S. Ray; Myers, R. M.

    1994-01-01

    Applied-field magnetoplasmadynamic (MPD) thruster performance is below levels required for primary propulsion missions. While MPD thruster performance has been found to increase with the magnitude of the applied-field strength, there is currently little understanding of the impact of applied-field shape on thruster performance. The results of a study in which a single applied-field thruster was operated using three solenoidal magnets with diameters of 12.7, 15.2, and 30.4-cm are presented. Thruster voltage and anode power deposition were measured for each applied field shape over a range of field strengths. Plume electron number density and temperature distributions were measured using a Langmuir probe in an effort to determine the effect of field shape on plume confinement by the diverging magnetic-field for each of the three magnetic field shapes. Results show that the dependence of the measured thruster characteristics on field shape were non-monotonic and that the field shape had a significant effect on the plume density and temperature profiles.

  3. Hybrid Shielding for Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Mullins, David; Royal, Kevin

    2017-01-01

    Precision symmetry measurements such as the search for the electric dipole moment of the neutron require magnetic shielding rooms to reduce the ambient field to the pT scale. The massive mu-metal sheets and large separation between layers make these shield rooms bulky and expensive. Active field cancellation systems used to reduce the surrounding field are limited in uniformity of cancellation. A novel approach to reducing the space between shield layers and increasing the effectiveness of active cancellation is to combine the two systems into a hybrid system, with active and passive layers interspersed. We demonstrate this idea in a prototype with an active layer sandwiched between two passive layers of shielding.

  4. External Magnetic Field Reduction Techniques for the Advanced Stirling Radioisotope Generator

    NASA Technical Reports Server (NTRS)

    Niedra, Janis M.; Geng, Steven M.

    2013-01-01

    Linear alternators coupled to high efficiency Stirling engines are strong candidates for thermal-to-electric power conversion in space. However, the magnetic field emissions, both AC and DC, of these permanent magnet excited alternators can interfere with sensitive instrumentation onboard a spacecraft. Effective methods to mitigate the AC and DC electromagnetic interference (EMI) from solenoidal type linear alternators (like that used in the Advanced Stirling Convertor) have been developed for potential use in the Advanced Stirling Radioisotope Generator. The methods developed avoid the complexity and extra mass inherent in data extraction from multiple sensors or the use of shielding. This paper discusses these methods, and also provides experimental data obtained during breadboard testing of both AC and DC external magnetic field devices.

  5. Interplanetary magnetic field data book

    NASA Technical Reports Server (NTRS)

    King, J. H.

    1975-01-01

    An interplanetary magnetic field (IMF) data set is presented that is uniform with respect to inclusion of cislunar IMF data only, and which has as complete time coverage as presently possible over a full solar cycle. Macroscale phenomena in the interplanetary medium (sector structure, heliolatitude variations, solar cycle variations, etc.) and other phenomena (e.g., ground level cosmic-ray events) for which knowledge of the IMF with hourly resolution is necessary, are discussed. Listings and plots of cislunar hourly averaged IMP parameters over the period November 27, 1963, to May 17, 1974, are presented along with discussion of the mutual consistency of the IMF data used herein. The magnetic tape from which the plots and listings were generated, which is available from the National Space Science Data Center (NSSDC), is also discussed.

  6. Static magnetic fields: animal studies.

    PubMed

    Saunders, Richard

    2005-01-01

    Various experimental studies carried out over the last 30-40 years have examined the effects of the chronic or acute exposure of laboratory animals to static magnetic fields. Many of the earlier studies have been adequately reviewed elsewhere; few adverse effects were identified. This review focuses on studies carried out more recently, mostly those using vertebrates, particularly mammals. Four main areas of investigation have been covered, viz., nervous system and behavioural studies, cardiovascular system responses, reproduction and development, and genotoxicity and cancer. Work on the role of the natural geomagnetic field in animal orientation and migration has been omitted. Generally, the acute responses found during exposure to static fields above about 4 T are consistent with those found in volunteer studies, namely the induction of flow potentials around the heart and the development of aversive/avoidance behaviour resulting from body movement in such fields. No consistently demonstrable effects of exposure to fields of approximately 1T and above have been seen on other behavioural or cardiovascular endpoints. In addition, no adverse effects of such fields on reproduction and development or on the growth and development of tumours have been firmly established. Overall, however, far too few animal studies have been carried out to reach any firm conclusions.

  7. Saturn's Magnetic Field and Magnetosphere.

    PubMed

    Smith, E J; Davis, L; Jones, D E; Coleman, P J; Colburn, D S; Dyal, P; Sonett, C P

    1980-01-25

    The Pioneer Saturn vector helium magnetometer has detected a bow shock and magnetopause at Saturn and has provided an accurate characterization of the planetary field. The equatorial surface field is 0.20 gauss, a factor of 3 to 5 times smaller than anticipated on the basis of attempted scalings from Earth and Jupiter. The tilt angle between the magnetic dipole axis and Saturn's rotation axis is < 1 degrees , a surprisingly small value. Spherical harmonic analysis of the measurements shows that the ratio of quadrupole to dipole moments is < 10 percent, indicating that the field is more uniform than those of the Earth or Jupiter and consistent with Saturn having a relatively small core. The field in the outer magnetosphere shows systematic departures from the dipole field, principally a compression of the field near noon and an equatorial orientation associated with a current sheet near dawn. A hydromagnetic wake resulting from the interaction of Titan with the rotating magnetosphere appears to have been observed.

  8. Experimental Setup for Magnetic-Field Tests of Small-Size Light Sensors at Jefferson Lab

    NASA Astrophysics Data System (ADS)

    Nickle, Cameron

    2013-10-01

    In preparation for the Electron Ion Collider, small-size sensors, such as Silicon photo-multipliers (SiPM) and Multi-Channel Plate (MCP) photo-multipliers are being considered for use in a Detection of Internally Reflected Cherenkov Light (DIRC) detector. Since DIRC will be operated in the strong field of a magnetic spectrometer, the gain of the sensors must be evaluated in high magnetic fields. A dedicated test facility, which makes use of a solenoid magnet with magnetic fields of up to 4.7 T, is being developed at Jefferson Labs. This paper describes the configuration and operation of an entirely non-magnetic dark box that will house the sensors during the tests and allows the sensors to be rotated about two axes relative to the field. This paper also describes the development of a ROOT-based analysis method to extract the gain of SiPMs from raw Analog-to-Digital-Converter (ADC) spectra as a function of the intensity of the magnetic field and the sensor's relative to angle to the field. The dark box and analysis method was tested with Hamamatsu mulitpixel SiPMs and our results are consistent with previous measurements of the same sensors. The methodology developed in this work will be routinely used for the upcoming high-B field tests.

  9. Magnetic field penetration of erosion switch plasmas

    NASA Astrophysics Data System (ADS)

    Mason, Rodney J.; Jones, Michael E.; Grossmann, John M.; Ottinger, Paul F.

    1988-10-01

    Computer simulations demonstrate that the entrainment (or advection) of magnetic field with the flow of cathode-emitted electrons can constitute a dominant mechanism for the magnetic field penetration of erosion switch plasmas. Cross-field drift in the accelerating electric field near the cathode starts the penetration process. Plasma erosion propagates the point for emission and magnetic field injection along the cathode toward the load-for the possibility of rapid switch opening.

  10. Harmonic undulator radiations with constant magnetic field

    NASA Astrophysics Data System (ADS)

    Jeevakhan, Hussain; Mishra, G.

    2015-01-01

    Harmonic undulators has been analysed in the presence of constant magnetic field along the direction of main undulator field. The spectrum modifications in harmonic undulator radiations and intensity degradation as a function of constant magnetic field magnitude at fundamental and third harmonics have been evaluated with a numerical integration method and generalised Bessel function. The role of harmonic field to overcome the intensity reduction due to constant magnetic field and energy spread in electron beam has also been demonstrated.

  11. Low-noise pulsed pre-polarization magnet system for ultra-low field NMR

    SciTech Connect

    Sims, James R; Schilling, Josef B; Swenson, Charles A; Gardner, David L; Matlashov, Andrei N; Ammerman, Curti N

    2009-01-01

    A liquid cooled, pulsed electromagnet of solenoid configuration suitable for duty in an ultra-low field nuclear magnetic resonance system has been designed, fabricated and successfully operated. The magnet design minimizes Johnson noise, minimizes the hydrogen signal and incorporates minimal metal and no ferromagnetic materials. In addition, an acoustically quiet cooling system permitting 50% duty cycle operation was achieved by designing for single-phase, laminar flow, forced convection cooling. Winding, conductor splicing and epoxy impregnation techniques were successfully developed to produce a coil winding body with integral cooling passageways and adequate structural integrity. Issues of material compatibility, housing, coolant flow system and heat rejection system design will be discussed. Additionally, this pulsed electromagnet design has been extended to produce a boiling liquid cooled version in a paired solenoid configuration suitable for duty in an ultra-low field nuclear magnetic resonance system. This pair of liquid nitrogen cooled coils is currently being tested and commissioned. Issues of material compatibility, thermal insulation, thermal contraction, housing and coolant flow design are discussed.

  12. Graphene in high magnetic fields

    NASA Astrophysics Data System (ADS)

    Orlita, Milan; Escoffier, Walter; Plochocka, Paulina; Raquet, Bertrand; Zeitler, Uli

    2013-01-01

    Carbon-based nano-materials, such as graphene and carbon nanotubes, represent a fascinating research area aiming at exploring their remarkable physical and electronic properties. These materials not only constitute a playground for physicists, they are also very promising for practical applications and are envisioned as elementary bricks of the future of the nano-electronics. As for graphene, its potential already lies in the domain of opto-electronics where its unique electronic and optical properties can be fully exploited. Indeed, recent technological advances have demonstrated its effectiveness in the fabrication of solar cells and ultra-fast lasers, as well as touch-screens and sensitive photo-detectors. Although the photo-voltaic technology is now dominated by silicon-based devices, the use of graphene could very well provide higher efficiency. However, before the applied research to take place, one must first demonstrates the operativeness of carbon-based nano-materials, and this is where the fundamental research comes into play. In this context, the use of magnetic field has been proven extremely useful for addressing their fundamental properties as it provides an external and adjustable parameter which drastically modifies their electronic band structure. In order to induce some significant changes, very high magnetic fields are required and can be provided using both DC and pulsed technology, depending of the experimental constraints. In this article, we review some of the challenging experiments on single nano-objects performed in high magnetic and low temperature. We shall mainly focus on the high-field magneto-optical and magneto-transport experiments which provided comprehensive understanding of the peculiar Landau level quantization of the Dirac-type charge carriers in graphene and thin graphite.

  13. Permanent Magnet Ecr Plasma Source With Magnetic Field Optimization

    DOEpatents

    Doughty, Frank C.; Spencer, John E.

    2000-12-19

    In a plasma-producing device, an optimized magnet field for electron cyclotron resonance plasma generation is provided by a shaped pole piece. The shaped pole piece adjusts spacing between the magnet and the resonance zone, creates a convex or concave resonance zone, and decreases stray fields between the resonance zone and the workpiece. For a cylindrical permanent magnet, the pole piece includes a disk adjacent the magnet together with an annular cylindrical sidewall structure axially aligned with the magnet and extending from the base around the permanent magnet. The pole piece directs magnetic field lines into the resonance zone, moving the resonance zone further from the face of the magnet. Additional permanent magnets or magnet arrays may be utilized to control field contours on a local scale. Rather than a permeable material, the sidewall structure may be composed of an annular cylindrical magnetic material having a polarity opposite that of the permanent magnet, creating convex regions in the resonance zone. An annular disk-shaped recurve section at the end of the sidewall structure forms magnetic mirrors keeping the plasma off the pole piece. A recurve section composed of magnetic material having a radial polarity forms convex regions and/or magnetic mirrors within the resonance zone.

  14. Capture and Transport of Laser Accelerated Protons by Pulsed Magnetic Fields: Advancements Toward Laser-Based Proton Therapy

    NASA Astrophysics Data System (ADS)

    Burris-Mog, Trevor J.

    The interaction of intense laser light (I > 10 18 W/cm2) with a thin target foil leads to the Target Normal Sheath Acceleration mechanism (TNSA). TNSA is responsible for the generation of high current, ultra-low emittance proton beams, which may allow for the development of a compact and cost effective proton therapy system for the treatment of cancer. Before this application can be realized, control is needed over the large divergence and the 100% kinetic energy spread that are characteristic of TNSA proton beams. The work presented here demonstrates control over the divergence and energy spread using strong magnetic fields generated by a pulse power solenoid. The solenoidal field results in a parallel proton beam with a kinetic energy spread DeltaE/E = 10%. Assuming that next generation lasers will be able to operate at 10 Hz, the 10% spread in the kinetic energy along with the 23% capture efficiency of the solenoid yield enough protons per laser pulse to, for the first time, consider applications in Radiation Oncology. Current lasers can generate proton beams with kinetic energies up to 67.5 MeV, but for therapy applications, the proton kinetic energy must reach 250 MeV. Since the maximum kinetic energy Emax of the proton scales with laser light intensity as Emax ∝ I0.5, next generation lasers may very well accelerate 250 MeV protons. As the kinetic energy of the protons is increased, the magnetic field strength of the solenoid will need to increase. The scaling of the magnetic field B with the kinetic energy of the protons follows B ∝ E1/2. Therefor, the field strength of the solenoid presented in this work will need to be increased by a factor of 2.4 in order to accommodate 250 MeV protons. This scaling factor seems reasonable, even with present technology. This work not only demonstrates control over beam divergence and energy spread, it also allows for us to now perform feasibility studies to further research what a laser-based proton therapy system

  15. Near-Field Magnetic Dipole Moment Analysis

    NASA Technical Reports Server (NTRS)

    Harris, Patrick K.

    2003-01-01

    This paper describes the data analysis technique used for magnetic testing at the NASA Goddard Space Flight Center (GSFC). Excellent results have been obtained using this technique to convert a spacecraft s measured magnetic field data into its respective magnetic dipole moment model. The model is most accurate with the earth s geomagnetic field cancelled in a spherical region bounded by the measurement magnetometers with a minimum radius large enough to enclose the magnetic source. Considerably enhanced spacecraft magnetic testing is offered by using this technique in conjunction with a computer-controlled magnetic field measurement system. Such a system, with real-time magnetic field display capabilities, has been incorporated into other existing magnetic measurement facilities and is also used at remote locations where transport to a magnetics test facility is impractical.

  16. The large superconducting solenoids for the g-2 muon storage ring

    SciTech Connect

    Bunce, G.; Cullen, J.; Danby, G.

    1994-12-01

    The g-2 muon storage ring at Brookhaven National Laboratory consists of four large superconducting solenoids. The two outer solenoids, which are 15.1 meters in diameter, share a common cryostat. The two inner solenoids, which are 13.4 meters in diameter, are in separate cryostats. The two 24 turn inner solenoids are operated at an opposite polarity from the two 24 turn outer solenoids. This generates a dipole field between the inner and outer solenoids. The flux between the solenoids is returned through a C shaped iron return yoke that also shapes the dipole field. The integrated field around the 14 meter diameter storage ring must be good to about 1 part in one million over the 90 mm dia. circular cross section where the muons are stored, averaged over the azimuth. When the four solenoids carry their 5300 A design current, the field in the 18 centimeter gap between the poles is 1.45 T. When the solenoid operates at its design current 5.5 MJ is stored between the poles. The solenoids were wound on site at Brookhaven National Laboratory. The cryostats were built around the solenoid windings which are indirectly cooled using two-phase helium.

  17. Orientation dependent cantilever torque magnetometry in high magnetic fields and low lemperatures

    NASA Astrophysics Data System (ADS)

    Chaparala, M. V.

    1996-03-01

    The measurement of the magnetic torque τ, as a function of the orientation of the field with respect to the sample axes θ, is a very sensitive and direct method for measuring the anisotropy of magnetic thin films, high Tc superconductors, and other anisotropic systems. With traditional torque magnetometers the limitations of the available sample volume at cryogenic temperature has necessitated the use of a horizontal field, split coil magnets. While solenoid coil vertical field magnets provide much higher fields, the sample space limitations have excluded their use in these measurements. We have designed and built a rotator for the high field magnets at NHMFL that will accomodate the single crystal silicon cantilever magnetometer(M. Chaparala, O.H. Chung and M.J. Naughton, A.I.P. Conf. Proc. 273, 407 (1992).). With this setup we have extended the range of torque magnetometry to high magnetic fields (20T) and low temperatures (0.5K). The setup has an ultimate angular resolution of about a millidegree. I will summarize on the design and performance of this rotator/cantilever torque magnetometer combination and present the results of the the torque measurements on a Tl_2212 single crystal.

  18. Magnetic field effects on microwave absorbing materials

    NASA Technical Reports Server (NTRS)

    Goldberg, Ira; Hollingsworth, Charles S.; Mckinney, Ted M.

    1991-01-01

    The objective of this program was to gather information to formulate a microwave absorber that can work in the presence of strong constant direct current (DC) magnetic fields. The program was conducted in four steps. The first step was to investigate the electrical and magnetic properties of magnetic and ferrite microwave absorbers in the presence of strong magnetic fields. This included both experimental measurements and a literature survey of properties that may be applicable to finding an appropriate absorbing material. The second step was to identify those material properties that will produce desirable absorptive properties in the presence of intense magnetic fields and determine the range of magnetic field in which the absorbers remain effective. The third step was to establish ferrite absorber designs that will produce low reflection and adequate absorption in the presence of intense inhomogeneous static magnetic fields. The fourth and final step was to prepare and test samples of such magnetic microwave absorbers if such designs seem practical.

  19. Magnetic field observations in Comet Halley's coma

    NASA Astrophysics Data System (ADS)

    Riedler, W.; Schwingenschuh, K.; Yeroshenko, Ye. G.; Styashkin, V. A.; Russell, C. T.

    1986-05-01

    During the encounter with Comet Halley, the magnetometer (MISCHA) aboard the Vega 1 spacecraft observed an increased level of magnetic field turbulence, resulting from an upstream bow wave. Both Vega spacecraft measured a peak field strength of 70-80 nT and observed draping of magnetic field lines around the cometary obstacle. An unexpected rotation of the magnetic field vector was observed, which may reflect either penetration of magnetic field lines into a diffuse layer related to the contact surface separating the solar-wind and cometary plasma, or the persistence of pre-existing interplanetary field structures.

  20. Magnetic Trapping of Bacteria at Low Magnetic Fields

    PubMed Central

    Wang, Z. M.; Wu, R. G.; Wang, Z. P.; Ramanujan, R. V.

    2016-01-01

    A suspension of non-magnetic entities in a ferrofluid is referred to as an inverse ferrofluid. Current research to trap non-magnetic entities in an inverse ferrofluid focuses on using large permanent magnets to generate high magnetic field gradients, which seriously limits Lab-on-a-Chip applications. On the other hand, in this work, trapping of non-magnetic entities, e.g., bacteria in a uniform external magnetic field was studied with a novel chip design. An inverse ferrofluid flows in a channel and a non-magnetic island is placed in the middle of this channel. The magnetic field was distorted by this island due to the magnetic susceptibility difference between this island and the surrounding ferrofluid, resulting in magnetic forces applied on the non-magnetic entities. Both the ferromagnetic particles and the non-magnetic entities, e.g., bacteria were attracted towards the island, and subsequently accumulate in different regions. The alignment of the ferrimagnetic particles and optical transparency of the ferrofluid was greatly enhanced by the bacteria at low applied magnetic fields. This work is applicable to lab-on-a-chip based detection and trapping of non-magnetic entities bacteria and cells. PMID:27254771

  1. Magnetic Trapping of Bacteria at Low Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Wang, Z. M.; Wu, R. G.; Wang, Z. P.; Ramanujan, R. V.

    2016-06-01

    A suspension of non-magnetic entities in a ferrofluid is referred to as an inverse ferrofluid. Current research to trap non-magnetic entities in an inverse ferrofluid focuses on using large permanent magnets to generate high magnetic field gradients, which seriously limits Lab-on-a-Chip applications. On the other hand, in this work, trapping of non-magnetic entities, e.g., bacteria in a uniform external magnetic field was studied with a novel chip design. An inverse ferrofluid flows in a channel and a non-magnetic island is placed in the middle of this channel. The magnetic field was distorted by this island due to the magnetic susceptibility difference between this island and the surrounding ferrofluid, resulting in magnetic forces applied on the non-magnetic entities. Both the ferromagnetic particles and the non-magnetic entities, e.g., bacteria were attracted towards the island, and subsequently accumulate in different regions. The alignment of the ferrimagnetic particles and optical transparency of the ferrofluid was greatly enhanced by the bacteria at low applied magnetic fields. This work is applicable to lab-on-a-chip based detection and trapping of non-magnetic entities bacteria and cells.

  2. Chiral plasmons without magnetic field

    NASA Astrophysics Data System (ADS)

    Song, Justin C. W.

    2016-04-01

    Plasmons, the collective oscillations of interacting electrons, possess emergent properties that dramatically alter the optical response of metals. We predict the existence of a new class of plasmons—chiral Berry plasmons (CBPs)—for a wide range of 2D metallic systems including gapped Dirac materials. As we show, in these materials the interplay between Berry curvature and electron-electron interactions yields chiral plasmonic modes at zero magnetic field. The CBP modes are confined to system boundaries, even in the absence of topological edge states, with chirality manifested in split energy dispersions for oppositely directed plasmon waves. We unveil a rich CBP phenomenology and propose setups for realizing them, including in anomalous Hall metals and optically pumped 2D Dirac materials. Realization of CBPs will offer a powerful paradigm for magnetic field-free, subwavelength optical nonreciprocity, in the mid-IR to terahertz range, with tunable splittings as large as tens of THz, as well as sensitive all-optical diagnostics of topological bands.

  3. Chiral plasmons without magnetic field

    PubMed Central

    Song, Justin C. W.; Rudner, Mark S.

    2016-01-01

    Plasmons, the collective oscillations of interacting electrons, possess emergent properties that dramatically alter the optical response of metals. We predict the existence of a new class of plasmons—chiral Berry plasmons (CBPs)—for a wide range of 2D metallic systems including gapped Dirac materials. As we show, in these materials the interplay between Berry curvature and electron–electron interactions yields chiral plasmonic modes at zero magnetic field. The CBP modes are confined to system boundaries, even in the absence of topological edge states, with chirality manifested in split energy dispersions for oppositely directed plasmon waves. We unveil a rich CBP phenomenology and propose setups for realizing them, including in anomalous Hall metals and optically pumped 2D Dirac materials. Realization of CBPs will offer a powerful paradigm for magnetic field-free, subwavelength optical nonreciprocity, in the mid-IR to terahertz range, with tunable splittings as large as tens of THz, as well as sensitive all-optical diagnostics of topological bands. PMID:27071090

  4. The flexible magnetic field thruster

    NASA Technical Reports Server (NTRS)

    Brophy, J. R.; Wilbur, P. J.

    1982-01-01

    The thruster is designed so that ion currents to various internal surfaces can be measured directly; these measurements facilitate calculations of the distribution of ion currents inside the discharge chamber. Experiments are described suggesting that the distribution of ion currents inside the discharge chamber is strongly dependent on the shape and strength of the magnetic field but independent of the discharge current, discharge voltage, and neutral flow rate. Measurements of the energy cost per plasma ion suggest that this cost decreases with increasing magnetic field strength as a consequence of increased anode shielding from the primary electrons. Energy costs per argon plasma ion as low as 50 eV are measured. The energy cost per beam ion is found to be a function of the energy cost per plasma ion, extracted ion fraction, and discharge voltage. Part of the energy cost per beam ion has to do with creating many ions in the plasma and then extracting only a fraction of them into the beam. The balance of the energy goes into accelerating the remaining plasma ions into the walls of the discharge chamber.

  5. Magnetic field waves at Uranus

    NASA Technical Reports Server (NTRS)

    Smith, Charles W.; Goldstein, Melvyn L.; Lepping, Ronald P.; Mish, William H.; Wong, Hung K.

    1994-01-01

    The research efforts funded by the Uranus Data Analysis Program (UDAP) grant to the Bartol Research Institute (BRI) involved the study of magnetic field waves associated with the Uranian bow shock. Upstream wave studies are motivated as a study of the physics of collisionless shocks. Collisionless shocks in plasmas are capable of 'reflecting' a fraction of the incoming thermal particle distribution and directing the resulting energetic particle motion back into the upstream region. Once within the upstream region, the backward streaming energetic particles convey information of the approaching shock to the supersonic flow. This particle population is responsible for the generation of upstream magnetic and electrostatic fluctuations known as 'upstream waves', for slowing the incoming wind prior to the formation of the shock ramp, and for heating of the upstream plasma. The waves produced at Uranus not only differed in several regards from the observations at other planetary bow shocks, but also gave new information regarding the nature of the reflected particle populations which were largely unmeasurable by the particle instruments. Four distinct magnetic field wave types were observed upstream of the Uranian bow shock: low-frequency Alfven or fast magnetosonic waves excited by energetic protons originating at or behind the bow shock; whistler wave bursts driven by gyrating ion distributions within the shock ramp; and two whistler wave types simultaneously observed upstream of the flanks of the shock and argued to arise from resonance with energetic electrons. In addition, observations of energetic particle distributions by the LECP experiment, thermal particle populations observed by the PLS experiment, and electron plasma oscillations recorded by the PWS experiment proved instrumental to this study and are included to some degree in the papers and presentations supported by this grant.

  6. Exploring Magnetic Fields with a Compass

    ERIC Educational Resources Information Center

    Lunk, Brandon; Beichner, Robert

    2011-01-01

    A compass is an excellent classroom tool for the exploration of magnetic fields. Any student can tell you that a compass is used to determine which direction is north, but when paired with some basic trigonometry, the compass can be used to actually measure the strength of the magnetic field due to a nearby magnet or current-carrying wire. In this…

  7. Deformation of Water by a Magnetic Field

    ERIC Educational Resources Information Center

    Chen, Zijun; Dahlberg, E. Dan

    2011-01-01

    After the discovery that superconducting magnets could levitate diamagnetic objects, researchers became interested in measuring the repulsion of diamagnetic fluids in strong magnetic fields, which was given the name "The Moses Effect." Both for the levitation experiments and the quantitative studies on liquids, the large magnetic fields necessary…

  8. Baryon onset in a magnetic field

    SciTech Connect

    Haber, Alexander; Preis, Florian; Schmitt, Andreas

    2016-01-22

    The critical baryon chemical potential for the onset of nuclear matter is a function of the vacuum mass and the binding energy. Both quantities are affected by an external magnetic field. We show within two relativistic mean-field models – including magnetic catalysis, but omitting the anomalous magnetic moment – that a magnetic field increases both the vacuum mass and the binding energy. For sufficiently large magnetic fields, the effect on the vacuum mass dominates and as a result the critical baryon chemical potential is increased.

  9. Analysis of magnetic field levels at KSC

    NASA Technical Reports Server (NTRS)

    Christodoulou, Christos G.

    1994-01-01

    The scope of this work is to evaluate the magnetic field levels of distribution systems and other equipment at Kennedy Space Center (KSC). Magnetic fields levels in several operational areas and various facilities are investigated. Three dimensional mappings and contour are provided along with the measured data. Furthermore, the portion of magnetic fields generated by the 60 Hz fundamental frequency and the portion generated by harmonics are examined. Finally, possible mitigation techniques for attenuating fields from electric panels are discussed.

  10. Magnetic field gradiometer. Final technical report

    SciTech Connect

    Fraser-Smith, A.C.

    1983-02-01

    This report has two principal goals. First, to present a general review of magnetic field gradiometers and, second, to provide new data concerning these gradiometers, including new information about their response to magnetic dipole fields. A system of nomenclature is introduced that is consistent with the mathematical concept of gradient and which provides a basis for discussions of the different functions of magnetic field gradiometers and differential magnetometers. The distinction between component gradiometers and total field gradiometers is also stressed.

  11. Transient magnetic field and temperature modeling in large magnet applications

    SciTech Connect

    Gurol, H.; Hardy, G.E.; Peck, S.D.; Leung, E. . Space Systems Div.)

    1989-07-01

    This paper discusses a coupled magnetic/thermal model developed to study heat and magnetic field diffusion in conducting materials subject to time-varying external fields. There are numerous applications, both military and commercial. These include: energy storage devices, pulsed power transformers, and electromagnetic launchers. The time scales of interest may range from a magnetic field pulse of a microsecond in an electromagnetic launcher, to hundreds of seconds in an energy storage magnet. The problem can be dominated by either the magnetic field or heat diffusion, depending on the temperature and the material properties of the conductor. In general, heat diffuses much more rapidly in high electrical conductivity materials of cryogenic temperatures. The magnetic field takes longer to diffuse, since screening currents can be rapidly set up which shield the interior of the material from further magnetic field penetration. Conversely, in high resistivity materials, the magnetic field diffuses much more rapidly. A coupled two-dimensional thermal/magnetic model has been developed. The results of this model, showing the time and spatial variation of the magnetic field and temperature, are discussed for the projectile of an electromagnetic launcher.

  12. Abnormal Magnetic Field Effects on Electrogenerated Chemiluminescence

    NASA Astrophysics Data System (ADS)

    Pan, Haiping; Shen, Yan; Wang, Hongfeng; He, Lei; Hu, Bin

    2015-03-01

    We report abnormal magnetic field effects on electrogenerated chemiluminescence (MFEECL) based on triplet emission from the Ru(bpy)3Cl2-TPrA electrochemical system: the appearance of MFEECL after magnetic field ceases. In early studies the normal MFEECL have been observed from electrochemical systems during the application of magnetic field. Here, the abnormal MFEECL suggest that the activated charge-transfer [Ru(bpy)33+ … TPrA•] complexes may become magnetized in magnetic field and experience a long magnetic relaxation after removing magnetic field. Our analysis indicates that the magnetic relaxation can gradually increase the density of charge-transfer complexes within reaction region due to decayed magnetic interactions, leading to a positive component in the abnormal MFEECL. On the other hand, the magnetic relaxation facilitates an inverse conversion from triplets to singlets within charge-transfer complexes. The inverse triplet --> singlet conversion reduces the density of triplet light-emitting states through charge-transfer complexes and gives rise to a negative component in the abnormal MFEECL. The combination of positive and negative components can essentially lead to a non-monotonic profile in the abnormal MFEECL after ceasing magnetic field. Nevertheless, our experimental studies may reveal un-usual magnetic behaviors with long magnetic relaxation from the activated charge-transfer [Ru(bpy)33+ … TPrA•] complexes in solution at room temperature.

  13. On the theory of magnetic field generation by relativistically strong laser radiation

    SciTech Connect

    Berezhiani, V.I.; Shatashvili, N.L.; Mahajan, S.M. |

    1996-07-01

    The authors consider the interaction of subpicosecond relativistically strong short laser pulses with an underdense cold unmagnetized electron plasma. It is shown that the strong plasma inhomogeneity caused by laser pulses results in the generation of a low frequency (quasistatic) magnetic field. Since the electron density distribution is determined completely by the pump wave intensity, the generated magnetic field is negligibly small for nonrelativistic laser pulses but increases rapidly in the ultrarelativistic case. Due to the possibility of electron cavitation (complete expulsion of electrons from the central region) for narrow and intense beams, the increase in the generated magnetic field slows down as the beam intensity is increased. The structure of the magnetic field closely resembles that of the field produced by a solenoid; the field is maximum and uniform in the cavitation region, then it falls, changes polarity and vanishes. In extremely dense plasmas, highly intense laser pulses in the self-channeling regime can generate magnetic fields {approximately} 100 Mg and greater.

  14. Application peculiarities of magnetic materials for protection from magnetic fields

    NASA Astrophysics Data System (ADS)

    Wai, P.; Dmitrenko, V.; Grabchikov, S.; Vlasik, K.; Novikov, A.; Petrenko, D.; Trukhanov, V.; Ulin, S.; Uteshev, Z.; Chernysheva, V.; Shustov, A.

    2016-02-01

    In different materials for magnetic shields, the maximum permeability is achieved for different values of the magnetic field. This determines the choice of material. So for protection from magnetic fields strength of 10 - 150 A/m it is advisable to apply the amorphous ribbon 84KXCP. For stronger fields (more than 400 A/m) it is recommended to use MFS based on Ni20Fe80. Use of these materials allows creating an effective shield working in a wide range of magnetic field strengths.

  15. Unique topological characterization of braided magnetic fields

    SciTech Connect

    Yeates, A. R.; Hornig, G.

    2013-01-15

    We introduce a topological flux function to quantify the topology of magnetic braids: non-zero, line-tied magnetic fields whose field lines all connect between two boundaries. This scalar function is an ideal invariant defined on a cross-section of the magnetic field, and measures the average poloidal magnetic flux around any given field line, or the average pairwise crossing number between a given field line and all others. Moreover, its integral over the cross-section yields the relative magnetic helicity. Using the fact that the flux function is also an action in the Hamiltonian formulation of the field line equations, we prove that it uniquely characterizes the field line mapping and hence the magnetic topology.

  16. Magnetic Field Synthesis for Microwave Magnetics.

    DTIC Science & Technology

    1982-04-01

    Ferromianetic Spheroids," J. Appl. Pl)v, . Vol. 29, (1958), p. 318. 12. II. Suhl, "The Nonlinear Behavior of Ferrites at Hiqh Microwave Sinnal Leveis," Proc...uniformly magnetized ferrite with the effects of exchange included. Using this method , a number of solutions (both exact and approximate) to the linearized...1969). 28. D. D. Stancil, "Magnetostatic Wave Precursors in Ferrite Thin Films Part I: Theory," Memorandum to Microwave and Quantum Magnetics Group

  17. Bipolar pulse field for magnetic refrigeration

    DOEpatents

    Lubell, Martin S.

    1994-01-01

    A magnetic refrigeration apparatus includes first and second steady state magnets, each having a field of substantially equal strength and opposite polarity, first and second bodies made of magnetocaloric material disposed respectively in the influence of the fields of the first and second steady state magnets, and a pulsed magnet, concentric with the first and second steady state magnets, and having a field which cycles between the fields of the first and second steady state magnets, thereby cyclically magnetizing and demagnetizing and thus heating and cooling the first and second bodies. Heat exchange apparatus of suitable design can be used to expose a working fluid to the first and second bodies of magnetocaloric material. A controller is provided to synchronize the flow of working fluid with the changing states of magnetization of the first and second bodies.

  18. Bipolar pulse field for magnetic refrigeration

    DOEpatents

    Lubell, M.S.

    1994-10-25

    A magnetic refrigeration apparatus includes first and second steady state magnets, each having a field of substantially equal strength and opposite polarity, first and second bodies made of magnetocaloric material disposed respectively in the influence of the fields of the first and second steady state magnets, and a pulsed magnet, concentric with the first and second steady state magnets, and having a field which cycles between the fields of the first and second steady state magnets, thereby cyclically magnetizing and demagnetizing and thus heating and cooling the first and second bodies. Heat exchange apparatus of suitable design can be used to expose a working fluid to the first and second bodies of magnetocaloric material. A controller is provided to synchronize the flow of working fluid with the changing states of magnetization of the first and second bodies. 2 figs.

  19. Homogenous BSCCO-2212 Round Wires for Very High Field Magnets

    SciTech Connect

    Dr. Scott Campbell Dr. Terry Holesinger Dr. Ybing Huang

    2012-06-30

    The performance demands on modern particle accelerators generate a relentless push towards higher field magnets. In turn, advanced high field magnet development places increased demands on superconducting materials. Nb3Sn conductors have been used to achieve 16 T in a prototype dipole magnet and are thought to have the capability for {approx}18 T for accelerator magnets (primarily dipoles but also higher order multipole magnets). However there have been suggestions and proposals for such magnets higher than 20 T. The High Energy Physics Community (HEP) has identified important new physics opportunities that are enabled by extremely high field magnets: 20 to 50 T solenoids for muon cooling in a muon collider (impact: understanding of neutrinos and dark matter); and 20+ T dipoles and quadrupoles for high energy hadron colliders (impact: discovery reach far beyond present). This proposal addresses the latest SBIR solicitation that calls for grant applications that seek to develop new or improved superconducting wire technologies for magnets that operate at a minimum of 12 Tesla (T) field, with increases up to 15 to 20 T sought in the near future (three to five years). The long-term development of accelerator magnets with fields greater than 20 T will require superconducting wires having significantly better high-field properties than those possessed by current Nb{sub 3}Sn or other A15 based wires. Given the existing materials science base for Bi-2212 wire processing, we believe that Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub y} (Bi-2212) round wires can be produced in km-long piece lengths with properties suitable to meet both the near term and long term needs of the HEP community. The key advance will be the translation of this materials science base into a robust, high-yield wire technology. While the processing and application of A15 materials have advanced to a much higher level than those of the copper oxide-based, high T{sub c} (HTS) counterparts, the HTS materials have

  20. Magnets producing arbitrarily directed magnetic fields used for SR x-ray diffraction and a proposal for a novel insertion device

    NASA Astrophysics Data System (ADS)

    Nakajima, Tetsuo; Yoshizawa, Masami

    1995-02-01

    After the manner of a goniometrical control of the incident beam and the crystal orientation by a four-circle goniometer, the strength and direction of the resultant magnetic fields produced by a set of three pairs of solenoids was goniometrically controlled by three bipolar electric-power sources. Two types of superconducting and normal Helmholtz-coil magnets were constructed. In the superconducting magnet, the coil constant is about 0.01259 TA-1 and the maximum magnetic field is about 0.5 T. The resultant maximum field is about 0.86 T in the [111] direction. In the normal magnet, the size of each coil is different. Each maximum field is up to about 337 Oe. Alternating- and direct-current magnetic fields applied to a crystal are able to vary from one direction [h1k1l1] to another [h2k2l2] while keeping parallel to an arbitrary curved surface. X-ray topographs of α-Fe-3%Si in magnetic fields swept in (110) from [002] via [22¯2], [11¯0], [22¯2¯], and [002¯] to [002] were taken using an N-type Helmholtz magnet. It is suggested that a coaxial serial connection of the two-dimensional astatic magnet with the above-mentioned specifications could be used as a new definitive-type insertion device, which could control the characteristics of polarized beams.

  1. Strong intrinsic mixing in vortex magnetic fields.

    PubMed

    Martin, James E; Shea-Rohwer, Lauren; Solis, Kyle J

    2009-07-01

    We report a method of magnetic mixing wherein a "vortex" magnetic field applied to a suspension of magnetic particles creates strong homogeneous mixing throughout the fluid volume. Experiments designed to elucidate the microscopic mechanism of mixing show that the torque is quadratic in the field, decreases with field frequency, and is optimized at a vortex field angle of approximately 55 degrees . Theory and simulations indicate that the field-induced formation of volatile particle chains is responsible for these phenomena. This technique has applications in microfluidic devices and is ideally suited to applications such as accelerating the binding of target biomolecules to biofunctionalized magnetic microbeads.

  2. Experimental studies of helical solenoid model based on YBCO tape-bridge joints

    SciTech Connect

    Yu, M.; Lombardo, V.; Turrioni, D.; Zlobin, A.V.; Flangan, G.; Lopes, M.L.; Johnson, R.P.; /Fermilab

    2011-06-01

    Helical solenoids that provide solenoid, helical dipole and helical gradient field components are designed for a helical cooling channel (HCC) proposed for cooling of muon beams in a muon collider. The high temperature superconductor (HTS), 12 mm wide and 0.1 mm thick YBCO tape, is used as the conductor for the highest-field section of HCC due to certain advantages, such as its electrical and mechanical properties. To study and address the design, and technological and performance issues related to magnets based on YBCO tapes, a short helical solenoid model based on double-pancake coils was designed, fabricated and tested at Fermilab. Splicing joints were made with Sn-Pb solder as the power leads and the connection between coils, which is the most critical element in the magnet that can limit the performance significantly. This paper summarizes the test results of YBCO tape and double-pancake coils in liquid nitrogen and liquid helium, and then focuses on the study of YBCO splices, including the soldering temperatures and pressures, and splice bending test.

  3. Normal zone propagation in superconducting focusing solenoids and related quench protection issues

    SciTech Connect

    Terechkine, I.; /Fermilab

    2007-06-01

    Superconducting solenoids are increasingly used as focusing lenses in transport channels of proton linear RF accelerators. If these accelerators employ superconducting RF cavities, each focusing lens is usually comprised of three coils connected in series: a main coil, which provides the needed focusing strength, and two bucking coils, that help to reduce magnetic field outside the lens. When a normal zone develops in any of the coils in a focusing lens, it propagates with a direction and a rate which depends on the coil and the specific part of the coil in which the quench first occurred. As a result of this propagation process (quenching), the temperature and/or voltage of parts of the lens can exceed safe limits, thus compromising lens reliability. On the other hand, the negative impact of quench events can be significantly mitigated if an external resistor is used to absorb a part of the energy stored in the magnetic field. This paper presents the main results of a solenoid quench protection study based on computational modeling of normal zone propagation in solenoid lenses being built for a superconducting linear RF accelerator under development at Fermilab.

  4. Superconducting magnetic control system for manipulation of particulate matter and magnetic probes in medical and industrial applications

    DOEpatents

    Cha, Yung Sheng; Hull, John R.; Askew, Thomas R.

    2006-07-11

    A system and method of controlling movement of magnetic material with at least first and second high temperature superconductors at spaced locations. A plurality of solenoids are associated with the superconductors to induce a persistent currents in preselected high temperature superconductors establishing a plurality of magnetic fields in response to pulsed currents introduced to one or more of the solenoids. Control mechanism in communication with said solenoids and/or said high temperature superconductors are used to demagnetize selected ones of the high temperature superconductors to reduce the magnetic fields substantially to zero. Magnetic material is moved between magnetic fields by establishing the presence thereof and thereafter reducing magnetic fields substantially to zero and establishing magnetic fields in other superconductors arranged in a predetermined configuration.

  5. Magnetic field waves at Uranus

    NASA Technical Reports Server (NTRS)

    Smith, Charles W.; Goldstein, Melvyn L.; Lepping, Ronald P.; Mish, William H.; Wong, Hung K.

    1991-01-01

    The proposed research efforts funded by the UDAP grant to the BRI involve the study of magnetic field waves associated with the Uranian bow shock. This is a collaborative venture bringing together investigators at the BRI, Southwest Research Institute (SwRI), and Goddard Space Flight Center (GSFC). In addition, other collaborations have been formed with investigators granted UDAP funds for similar studies and with investigators affiliated with other Voyager experiments. These investigations and the corresponding collaborations are included in the report. The proposed effort as originally conceived included an examination of waves downstream from the shock within the magnetosheath. However, the observations of unexpected complexity and diversity within the upstream region have necessitated that we confine our efforts to those observations recorded upstream of the bow shock on the inbound and outbound legs of the encounter by the Voyager 2 spacecraft.

  6. Development of a 0.5 T magnetic-core alternating-field demagnetizer

    NASA Astrophysics Data System (ADS)

    Schillinger, W. E.; Morris, E. R.; Coe, R. S.; Finn, D. R.

    2016-04-01

    We have constructed an alternating-field (AF) demagnetizer with a magnetic core in a passively air-cooled coil that can routinely operate at fields up to 0.5 T, almost 3 times higher than we could attain before in our commercial instrument. The field is powered by a commercial 1 kW power amplifier and is transverse to the bore, uniform to ±2% over a 25 mm paleomagnetic sample, and compatible with our existing sample handler for automated demagnetization and measurement. Even harmonics are ≤1 ppm of the fundamental and so generate negligible anhysteretic remanence. The much higher peak alternating field, 2 and 5 times that commonly available in air-core solenoidal and Helmhotz coil configurations, respectively, enables successful AF demagnetization of many samples that could not be completely demagnetized with commercially available equipment. This capability is especially useful for high-coercivity sedimentary and igneous rocks and extraterrestrial materials that contain magnetic minerals that alter during thermal demagnetization. In addition to the benefits, this instrument brings to our own research, a much broader potential impact is that it could replace the transverse coils of most automated AF demagnetization systems in use today, whether for discrete or continuous U-channel measurements, which are commonly limited to peak fields of ˜100 mT. Manual and tumbling demagnetizers would benefit as well by the ˜2 times increase in maximum field over those that can be attained by commercial solenoidal coils. Furthermore, we expect that it and similarly designed magnetic-core instruments will be capable of attaining even higher fields, of order 1 T.

  7. Representation of magnetic fields in space

    NASA Technical Reports Server (NTRS)

    Stern, D. P.

    1975-01-01

    Several methods by which a magnetic field in space can be represented are reviewed with particular attention to problems of the observed geomagnetic field. Time dependence is assumed to be negligible, and five main classes of representation are described by vector potential, scalar potential, orthogonal vectors, Euler potentials, and expanded magnetic field.

  8. DC-based magnetic field controller

    DOEpatents

    Kotter, Dale K.; Rankin, Richard A.; Morgan, John P,.

    1994-01-01

    A magnetic field controller for laboratory devices and in particular to dc operated magnetic field controllers for mass spectrometers, comprising a dc power supply in combination with improvements to a hall probe subsystem, display subsystem, preamplifier, field control subsystem, and an output stage.

  9. DC-based magnetic field controller

    DOEpatents

    Kotter, D.K.; Rankin, R.A.; Morgan, J.P.

    1994-05-31

    A magnetic field controller is described for laboratory devices and in particular to dc operated magnetic field controllers for mass spectrometers, comprising a dc power supply in combination with improvements to a Hall probe subsystem, display subsystem, preamplifier, field control subsystem, and an output stage. 1 fig.

  10. Static uniform magnetic fields and amoebae

    SciTech Connect

    Berk, S.G.; Srikanth, S.; Mahajan, S.M.; Ventrice, C.A.

    1997-03-01

    Three species of potentially pathogenic amoebae were exposed to 71 and 106.5 mT from constant homogeneous magnetic fields and examined for inhibition of population growth. The number of amoebae for three species was significantly less than controls after a 72 h exposure to the magnetic fields when the temperature was 20 C or above. Axenic cultures, i.e., cultures grown without bacteria, were significantly affected after only 24 h. In 20 of 21 tests using the three species, the magnetic field significantly inhibited the growth of amoebae. In one test in which the temperature was 20 C for 48 h, exposure to the magnetic field was not inhibitory. Final numbers of magnetic field-exposed amoebae ranged from 9 to 72% lower than the final numbers of unexposed controls, depending on the species. This research may lead to disinfection strategies utilizing magnetic fields for surfaces on which pathogenic amoebae may proliferate.

  11. Nonlinear energy dissipation of magnetic nanoparticles in oscillating magnetic fields

    NASA Astrophysics Data System (ADS)

    Soto-Aquino, D.; Rinaldi, C.

    2015-11-01

    The heating of magnetic nanoparticle suspensions subjected to alternating magnetic fields enables a variety of emerging applications such as magnetic fluid hyperthermia and triggered drug release. Rosensweig (2002) [25] obtained a model for the heat dissipation rate of a collection of non-interacting particles. However, the assumptions made in this analysis make it rigorously valid only in the limit of small applied magnetic field amplitude and frequency (i.e., values of the Langevin parameter that are much less than unity and frequencies below the inverse relaxation time). In this contribution we approach the problem from an alternative point of view by solving the phenomenological magnetization relaxation equation exactly for the case of arbitrary magnetic field amplitude and frequency and by solving a more accurate magnetization relaxation equation numerically. We also use rotational Brownian dynamics simulations of non-interacting magnetic nanoparticles subjected to an alternating magnetic field to estimate the rate of energy dissipation and compare the results of the phenomenological theories to the particle-scale simulations. The results are summarized in terms of a normalized energy dissipation rate and show that Rosensweig's expression provides an upper bound on the energy dissipation rate achieved at high field frequency and amplitude. Estimates of the predicted dependence of energy dissipation rate, quantified as specific absorption rate (SAR), on magnetic field amplitude and frequency, and particle core and hydrodynamic diameter, are also given.

  12. Magnetic field sensor for isotropically sensing an incident magnetic field in a sensor plane

    NASA Technical Reports Server (NTRS)

    Pant, Bharat B. (Inventor); Wan, Hong (Inventor)

    2001-01-01

    A magnetic field sensor that isotropically senses an incident magnetic field. This is preferably accomplished by providing a magnetic field sensor device that has one or more circular shaped magnetoresistive sensor elements for sensing the incident magnetic field. The magnetoresistive material used is preferably isotropic, and may be a CMR material or some form of a GMR material. Because the sensor elements are circular in shape, shape anisotropy is eliminated. Thus, the resulting magnetic field sensor device provides an output that is relatively independent of the direction of the incident magnetic field in the sensor plane.

  13. Electric-field and magnetic-field sensors

    NASA Astrophysics Data System (ADS)

    Wieckowski, T. W.

    1993-05-01

    Analysis of double-loaded loop antennas and their properties has led to the design of new measuring sensors which enable has led to determination of both electric field strength and magnetic field strength. Sensors of the design proposed are applicable to a quasipoint measurement providing independent determination of the electric and magnetic component of the field.

  14. Effect of tapered magnetic field on expanding laser-produced plasma for heavy-ion inertial fusion

    SciTech Connect

    Kanesue, Takeshi; Ikeda, Shunsuke

    2016-12-20

    A laser ion source is a promising candidate as an ion source for heavy ion inertial fusion (HIF), where a pulsed ultra-intense and low-charged heavy ion beam is required. It is a key development for a laser ion source to transport laser-produced plasma with a magnetic field to achieve a high current beam. The effect of a tapered magnetic field on laser produced plasma is demonstrated by comparing the results with a straight solenoid magnet. The magnetic field of interest is a wider aperture on a target side and narrower aperture on an extraction side. Furthermore, based on the experimentally obtained results, the performance of a scaled laser ion source for HIF was estimated.

  15. Effect of tapered magnetic field on expanding laser-produced plasma for heavy-ion inertial fusion

    DOE PAGES

    Kanesue, Takeshi; Ikeda, Shunsuke

    2016-12-20

    A laser ion source is a promising candidate as an ion source for heavy ion inertial fusion (HIF), where a pulsed ultra-intense and low-charged heavy ion beam is required. It is a key development for a laser ion source to transport laser-produced plasma with a magnetic field to achieve a high current beam. The effect of a tapered magnetic field on laser produced plasma is demonstrated by comparing the results with a straight solenoid magnet. The magnetic field of interest is a wider aperture on a target side and narrower aperture on an extraction side. Furthermore, based on the experimentallymore » obtained results, the performance of a scaled laser ion source for HIF was estimated.« less

  16. Magnetically modified bioсells in constant magnetic field

    NASA Astrophysics Data System (ADS)

    Abramov, E. G.; Panina, L. K.; Kolikov, V. A.; Bogomolova, E. V.; Snetov, V. N.; Cherepkova, I. A.; Kiselev, A. A.

    2017-02-01

    Paper addresses the inverse problem in determining the area, where the external constant magnetic field captures the biological cells modified by the magnetic nanoparticles. Zero velocity isolines, in area where the modified cells are captured by the magnetic field were determined by numerical method for two locations of the magnet. The problem was solved taking into account the gravitational field, magnetic induction, density of medium, concentration and size of cells, and size and magnetization of nanoparticles attached to the cell. Increase in the number of the nanoparticles attached to the cell and decrease in the cell' size, enlarges the area, where the modified cells are captured and concentrated by the magnet. Solution is confirmed by the visible pattern formation of the modified cells Saccharomyces cerevisiae.

  17. Swarm: ESA's Magnetic Field Mission

    NASA Astrophysics Data System (ADS)

    Drinkwater, M. R.; Haagmans, R.; Floberghagen, R.; Plank, G.; Menard, Y.

    2011-12-01

    Swarm is the fifth Earth Explorer mission in ESA's Living Planet Programme, and is scheduled for launch in 2012. The objective of the Swarm mission is to provide the best-ever survey of the geomagnetic field and its temporal evolution using a constellation of 3 identical satellites. The Mission shall deliver data that allow access to new insights into the Earth system by improved scientific understanding of the Earth's interior and near-Earth electromagnetic environment. After launch and triple satellite release at an initial altitude of about 490 km, a pair of the satellites will fly side-by-side with slowly decaying altitude, while the third satellite will be lifted to 530 km to complete the Swarm constellation. High-precision and high-resolution measurements of the strength, direction and variation of the magnetic field, complemented by precise navigation, accelerometer and electric field measurements, will provide the observations required to separate and model various sources of the geomagnetic field and near-Earth current systems. The mission science goals are to provide a unique view into Earth core dynamics, mantle conductivity, crustal magnetisation, ionospheric and magnetospheric current systems and upper atmosphere dynamics - ranging from understanding the geodynamo to contributing to space weather. The scientific objectives and results from recent scientific studies will be presented. In addition the current status of the project, which is presently approaching the final stage of the development phase, will be addressed. A consortium of European scientific institutes is developing a distributed processing system to produce geophysical (Level 2) data products to the Swarm user community. The setup of Swarm ground segment and the contents of the data products will be addressed. More information on the Swarm mission can be found at the mission web site (see URL below).

  18. Lessons Learned for the MICE Coupling Solenoid from the MICE Spectrometer Solenoids

    SciTech Connect

    Green, Michael A.; Wang, Li; Pan, Heng; Wu, Hong; Guo, Xinglong; Li, S. Y.; Zheng, S. X.; Virostek, Steve P.; DeMello, Allen J.; Li, Derun; Trillaud, Frederick; Zisman, Michael S.

    2010-05-30

    Tests of the spectrometer solenoids have taught us some important lessons. The spectrometer magnet lessons learned fall into two broad categories that involve the two stages of the coolers that are used to cool the magnets. On the first spectrometer magnet, the problems were centered on the connection of the cooler 2nd-stage to the magnet cold mass. On the first test of the second spectrometer magnet, the problems were centered on the cooler 1st-stage temperature and its effect on the operation of the HTS leads. The second time the second spectrometer magnet was tested; the cooling to the cold mass was still not adequate. The cryogenic designs of the MICE and MuCOOL coupling magnets are quite different, but the lessons learned from the tests of the spectrometer magnets have affected the design of the coupling magnets.

  19. Minimizing magnetic fields for precision experiments

    SciTech Connect

    Altarev, I.; Fierlinger, P.; Lins, T.; Marino, M. G.; Nießen, B.; Petzoldt, G.; Reisner, M.; Stuiber, S. Sturm, M.; Taggart Singh, J.; Taubenheim, B.; Rohrer, H. K.; Schläpfer, U.

    2015-06-21

    An increasing number of measurements in fundamental and applied physics rely on magnetically shielded environments with sub nano-Tesla residual magnetic fields. State of the art magnetically shielded rooms (MSRs) consist of up to seven layers of high permeability materials in combination with highly conductive shields. Proper magnetic equilibration is crucial to obtain such low magnetic fields with small gradients in any MSR. Here, we report on a scheme to magnetically equilibrate MSRs with a 10 times reduced duration of the magnetic equilibration sequence and a significantly lower magnetic field with improved homogeneity. For the search of the neutron's electric dipole moment, our finding corresponds to a 40% improvement of the statistical reach of the measurement. However, this versatile procedure can improve the performance of any MSR for any application.

  20. Free oscillations of magnetic fluid in strong magnetic field

    NASA Astrophysics Data System (ADS)

    Polunin, V. M.; Ryapolov, P. A.; Platonov, V. B.; Kuz'ko, A. E.

    2016-05-01

    The paper presents the esults of measuring the elastic parameters of an oscillatory system (coefficient of pondermotive elasticity, damping factor, and oscillation frequency) whose viscous inertial element is represented by a magnetic fluid confined in a tube by magnetic levitation in a strong magnetic field. The role of elasticity is played by the pondermotive force acting on thin layers at the upper and lower ends of the fluid column. It is shown that, by measuring the elastic oscillation frequencies of the magnetic fluid column, it is possible to develop a fundamentally new absolute method for determining the saturation magnetization of a magnetic colloid.

  1. Magnetic monopole field exposed by electrons

    NASA Astrophysics Data System (ADS)

    Béché, Armand; van Boxem, Ruben; van Tendeloo, Gustaaf; Verbeeck, Jo

    2014-01-01

    The experimental search for magnetic monopole particles has, so far, been in vain. Nevertheless, these elusive particles of magnetic charge have fuelled a rich field of theoretical study. Here, we created an approximation of a magnetic monopole in free space at the end of a long, nanoscopically thin magnetic needle. We experimentally demonstrate that the interaction of this approximate magnetic monopole field with a beam of electrons produces an electron vortex state, as theoretically predicted for a true magnetic monopole. This fundamental quantum mechanical scattering experiment is independent of the speed of the electrons and has consequences for all situations where electrons meet such monopole magnetic fields, as, for example, in solids. The set-up not only shows an attractive way to produce electron vortex states but also provides a unique insight into monopole fields and shows that electron vortices might well occur in unexplored solid-state physics situations.

  2. Magnetic vector field tag and seal

    DOEpatents

    Johnston, Roger G.; Garcia, Anthony R.

    2004-08-31

    One or more magnets are placed in a container (preferably on objects inside the container) and the magnetic field strength and vector direction are measured with a magnetometer from at least one location near the container to provide the container with a magnetic vector field tag and seal. The location(s) of the magnetometer relative to the container are also noted. If the position of any magnet inside the container changes, then the measured vector fields at the these locations also change, indicating that the tag has been removed, the seal has broken, and therefore that the container and objects inside may have been tampered with. A hollow wheel with magnets inside may also provide a similar magnetic vector field tag and seal. As the wheel turns, the magnets tumble randomly inside, removing the tag and breaking the seal.

  3. Bats Respond to Very Weak Magnetic Fields

    PubMed Central

    Tian, Lan-Xiang; Pan, Yong-Xin; Metzner, Walter; Zhang, Jin-Shuo; Zhang, Bing-Fang

    2015-01-01

    How animals, including mammals, can respond to and utilize the direction and intensity of the Earth’s magnetic field for orientation and navigation is contentious. In this study, we experimentally tested whether the Chinese Noctule, Nyctalus plancyi (Vespertilionidae) can sense magnetic field strengths that were even lower than those of the present-day geomagnetic field. Such field strengths occurred during geomagnetic excursions or polarity reversals and thus may have played an important role in the evolution of a magnetic sense. We found that in a present-day local geomagnetic field, the bats showed a clear preference for positioning themselves at the magnetic north. As the field intensity decreased to only 1/5th of the natural intensity (i.e., 10 μT; the lowest field strength tested here), the bats still responded by positioning themselves at the magnetic north. When the field polarity was artificially reversed, the bats still preferred the new magnetic north, even at the lowest field strength tested (10 μT), despite the fact that the artificial field orientation was opposite to the natural geomagnetic field (P<0.05). Hence, N. plancyi is able to detect the direction of a magnetic field even at 1/5th of the present-day field strength. This high sensitivity to magnetic fields may explain how magnetic orientation could have evolved in bats even as the Earth’s magnetic field strength varied and the polarity reversed tens of times over the past fifty million years. PMID:25922944

  4. Magnetic field spectrum at cosmological recombination revisited

    NASA Astrophysics Data System (ADS)

    Saga, Shohei; Ichiki, Kiyotomo; Takahashi, Keitaro; Sugiyama, Naoshi

    2015-06-01

    If vector type perturbations are present in the primordial plasma before recombination, the generation of magnetic fields is known to be inevitable through the Harrison mechanism. In the context of the standard cosmological perturbation theory, nonlinear couplings of first-order scalar perturbations create second-order vector perturbations, which generate magnetic fields. Here we reinvestigate the generation of magnetic fields at second-order in cosmological perturbations on the basis of our previous study, and extend it by newly taking into account the time evolution of purely second-order vector perturbations with a newly developed second-order Boltzmann code. We confirm that the amplitude of magnetic fields from the product-terms of the first-order scalar modes is consistent with the result in our previous study. However, we find, both numerically and analytically, that the magnetic fields from the purely second-order vector perturbations partially cancel out the magnetic fields from one of the product-terms of the first-order scalar modes, in the tight coupling regime in the radiation dominated era. Therefore, the amplitude of the magnetic fields on small scales, k ≳10 h Mpc-1 , is smaller than the previous estimates. The amplitude of the generated magnetic fields at cosmological recombination is about Brec=5.0 ×10-24 Gauss on k =5.0 ×10-1 h Mpc-1 . Finally, we discuss the reason for the discrepancies that exist in estimates of the amplitude of magnetic fields among other authors.

  5. Ferroelectric Cathodes in Transverse Magnetic Fields

    SciTech Connect

    Alexander Dunaevsky; Yevgeny Raitses; Nathaniel J. Fisch

    2002-07-29

    Experimental investigations of a planar ferroelectric cathode in a transverse magnetic field up to 3 kGs are presented. It is shown that the transverse magnetic field affects differently the operation of ferroelectric plasma cathodes in ''bright'' and ''dark'' modes in vacuum. In the ''bright'' mode, when the surface plasma is formed, the application of the transverse magnetic field leads to an increase of the surface plasma density. In the ''dark'' mode, the magnetic field inhibits the development of electron avalanches along the surface, as it does similarly in other kinds of surface discharges in the pre-breakdown mode.

  6. Simulation of Magnetic Field Guided Plasma Expansion

    NASA Astrophysics Data System (ADS)

    Ebersohn, Frans; Sheehan, J. P.; Gallimore, Alec; Shebalin, John

    2015-09-01

    Magnetic field guided expansion of a radio-frequency plasma was simulated with a quasi-one-dimensional particle-in-cell code. Two-dimensional effects were included in a one-dimensional particle-in-cell code by varying the cross-sectional area of the one dimensional domain and including forces due to the magnetic field. Acceleration of electrons by the magnetic field forces leads to the formation of potential structures which then accelerate the ions into a beam. Density changes due to the plasma expansion only weakly affect the ion acceleration. Rapidly diverging magnetic fields lead to more rapid acceleration and the electrons cool as they expand.

  7. Flow Transitions in a Rotating Magnetic Field

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Mazuruk, K.

    1996-01-01

    Critical Rayleigh numbers have been measured in a liquid metal cylinder of finite height in the presence of a rotating magnetic field. Several different stability regimes were observed, which were determined by the values of the Rayleigh and Hartmann numbers. For weak rotating magnetic fields and small Rayleigh numbers, the experimental observations can be explained by the existence of a single non-axisymmetric meridional roll rotating around the cylinder, driven by the azimuthal component of the magnetic field. The measured dependence of rotational velocity on magnetic field strength is consistent with the existence of laminar flow in this regime.

  8. Reducing Field Distortion in Magnetic Resonance Imaging

    NASA Technical Reports Server (NTRS)

    Eom, Byeong Ho; Penanen, Konstantin; Hahn, Inseob

    2010-01-01

    A concept for a magnetic resonance imaging (MRI) system that would utilize a relatively weak magnetic field provides for several design features that differ significantly from the corresponding features of conventional MRI systems. Notable among these features are a magnetic-field configuration that reduces (relative to the conventional configuration) distortion and blurring of the image, the use of a superconducting quantum interference device (SQUID) magnetometer as the detector, and an imaging procedure suited for the unconventional field configuration and sensor. In a typical application of MRI, a radio-frequency pulse is used to excite precession of the magnetic moments of protons in an applied magnetic field, and the decaying precession is detected for a short time following the pulse. The precession occurs at a resonance frequency proportional to the strengths of the magnetic field and the proton magnetic moment. The magnetic field is configured to vary with position in a known way; hence, by virtue of the aforesaid proportionality, the resonance frequency varies with position in a known way. In other words, position is encoded as resonance frequency. MRI using magnetic fields weaker than those of conventional MRI offers several advantages, including cheaper and smaller equipment, greater compatibility with metallic objects, and higher image quality because of low susceptibility distortion and enhanced spin-lattice-relaxation- time contrast. SQUID MRI is being developed into a practical MRI method for applied magnetic flux densities of the order of only 100 T

  9. Magnetic field evolution in interacting galaxies

    NASA Astrophysics Data System (ADS)

    Drzazga, R. T.; Chyży, K. T.; Jurusik, W.; Wiórkiewicz, K.

    2011-09-01

    Aims: Violent gravitational interactions can change the morphologies of galaxies and, by means of merging, transform them into elliptical galaxies. We aim to investigate how they affect the evolution of galactic magnetic fields. Methods: We selected 16 systems of interacting galaxies with available VLA archive radio data at 4.86 and 1.4 GHz and compared their radio emission and estimated magnetic field strengths with their star-forming activity, far-infrared emission, and the stage of tidal interaction. Results: The estimated mean of total magnetic field strength for our sample of interacting galaxies is 14 ± 5 μG, which is larger than for the non-interacting objects. The field regularity (of 0.27 ± 0.09) is lower than in typical spirals and indicates enhanced production of random magnetic fields in the interacting objects. We find a general evolution of magnetic fields: for weak interactions the strength of magnetic field is almost constant (10-15 μG) as interaction advances, then it increases up to 2× , peaks at the nuclear coalescence (25 μG), and decreases again, down to 5-6 μG, for the post-merger remnants. The main production of magnetic fields in colliding galaxies thus terminates somewhere close to the nuclear coalescence, after which magnetic field diffuses. The magnetic field strength for whole galaxies is weakly affected by the star formation rate (SFR), while the dependence is higher for galactic centres. We show that the morphological distortions visible in the radio total and polarized emission do not depend statistically on the global or local SFRs, while they do increase (especially in the polarization) with the advance of interaction. The constructed radio-far-infrared relations for interacting and non-interacting galaxies display a similar balance between the generation of cosmic rays, magnetic fields, and the production of the thermal energy and dust radiation. Conclusions: The regular magnetic fields are much more sensitive to

  10. Magnetic field strength in solar coronal waveguides

    NASA Astrophysics Data System (ADS)

    Arregui, I.; Asensio Ramos, A.

    2017-03-01

    We applied Bayesian techniques to the problem of inferring the magnetic field strength in transversely oscillating solar coronal loops from observed periods and damping times. This was done by computing the marginal posterior probability density for parameters such as the waveguide density, the density contrast, the transverse inhomogeneity length scale, and the magnetic field strength under the assumption that the observed waves can be modelled as standing or propagating magnetohydrodynamic (MHD) kink modes of magnetic flux tubes. Our results indicate that the magnetic field strength can be inferred, even if the densities inside and outside the structure are largely unknown. When information on plasma density is available, the method enables to self-consistently include this knowledge to further constrain the inferred magnetic field strength. The inclusion of the observed oscillation damping enables to obtain information on the transverse density structuring and considerably alters the obtained posterior for the magnetic field strength.

  11. Dynamics of a Finite Liquid Oxygen (LOX) Column in a Pulsed Magnetic Field

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert; Immer, Christopher; Lane, John; Simpson, James; Steinrock, T. (Technical Monitor)

    2002-01-01

    It is well known that liquid oxygen has a sufficient paramagnetic susceptibility that a strong magnetic field gradient can lift it in the earth's gravitational field. The movement of liquid oxygen is vital to the space program since it one of the primary oxidizers used for propulsion. Transport of liquid oxygen (LOX) via direct interaction of the magnetic fields (B field) with the fluid is a current topic of research and development at Kennedy Space Center, FL. This method of transporting (i.e. pumping) LOX may have particular advantages on Mars and other reduced gravitational environments, namely safety and reliability. This paper will address transport of a magnetic fluid, LOX, via phased-pulsed electromagnets acting on the edge of the column of fluid. The authors have developed a physical model from first-principles for the motion of a magnetic fluid in a particular U-tube geometry subjected to a pulsed magnetic field from an arbitrary solenoidal electromagnet. Experimental data that have been collected from the analogous geometry correlate well to that of the ab-initio calculations.

  12. Electric and magnetic energy at axion haloscopes

    NASA Astrophysics Data System (ADS)

    Ko, B. R.; Themann, H.; Jang, W.; Choi, J.; Kim, D.; Lee, M. J.; Lee, J.; Won, E.; Semertzidis, Y. K.

    2016-12-01

    We review the electro-magnetic energy at axion haloscopes and find that the electric and the corresponding magnetic energy stored in the cavity modes or, equivalently, the mode dependent electric and magnetic form factors are the same regardless of the position of the cavity inside the solenoid. Furthermore, we extend our argument to the cases satisfying ∇→×B→external=0 , where B→external is a static magnetic field provided by a magnet at an axion haloscope. Two typical magnets, solenoidal and toroidal, satisfy ∇→×B→external=0 ; thus, the electric and the corresponding magnetic energy stored in the cavity modes are always the same in both cases. The energy, however, is independent of the position of the cavity in axion haloscopes with a solenoid, and depends on those with a toroidal magnet.

  13. Magnetic field decay in model SSC dipoles

    SciTech Connect

    Gilbert, W.S.; Althaus, R.F.; Barale, P.J.; Benjegerdes, R.W.; Green, M.A.; Green, M.I.; Scanlan, R.M.

    1988-08-01

    We have observed that some of our model SSC dipoles have long time constant decays of the magnetic field harmonics with amplitudes large enough to result in significant beam loss, if they are not corrected. The magnets were run at constant current at the SSC injection field level of 0.3 tesla for one to three hours and changes in the magnetic field were observed. One explanation for the observed field decay is time dependent superconductor magnetization. Another explanation involves flux creep or flux flow. Data are presented on how the decay changes with previous flux history. Similar magnets with different Nb-Ti filament spacings and matrix materials have different long time field decay. A theoretical model using proximity coupling and flux creep for the observed field decay is discussed. 10 refs., 5 figs., 2 tabs.

  14. Supersolid phases in the magnetic fields

    NASA Astrophysics Data System (ADS)

    Wang, Ji-Guo; Yang, Shi-Jie

    2017-02-01

    We study the ground state phases of the ultracold atomic condensates loaded in a two-dimensional optical lattice with the magnetic fields. Apart from uniform superfluid (SF) phase, four types of supersolid (SS) phases in the presence of the uniform magnetic fluxes and two types of SS phases in the presence of the staggered magnetic fluxes are found. For the system without magnetic flux, except for a certain unit phase factor ϕ x (y) = π, the magnetic field has no effect on the system.

  15. Magnetic Field Investigations During ROSETTA's Steins Flyby

    NASA Astrophysics Data System (ADS)

    Glassmeier, K.; Auster, H.; Richter, I.; Motschmann, U.; RPC/ROMAP Teams

    2009-05-01

    During the recent Steins flyby of the ROSETTA spacecraft magnetic field measurements have been made with both, the RPC orbiter magnetometer and the ROMAP lander magnetometer. These combined magnetic field measurements allow a detailed examination of any magnetic signatures caused either directly by the asteroid or indirectly by Steins different modes of interaction with the solar wind. Comparing our measurements with simulation results show that Steins does not possess a significant remanent magnetization. The magnetization is estimated at less than 1 mAm2/kg. This is significantly different from results at Braille and Gaspra.

  16. The Evolution of the Earth's Magnetic Field.

    ERIC Educational Resources Information Center

    Bloxham, Jeremy; Gubbins, David

    1989-01-01

    Describes the change of earth's magnetic field at the boundary between the outer core and the mantle. Measurement techniques used during the last 300 years are considered. Discusses the theories and research for explaining the field change. (YP)

  17. Assembly of magnetic spheres in strong homogeneous magnetic field

    NASA Astrophysics Data System (ADS)

    Messina, René; Stanković, Igor

    2017-01-01

    The assembly in two dimensions of spherical magnets in strong magnetic field is addressed theoretically. It is shown that the attraction and assembly of parallel magnetic chains is the result of a delicate interplay of dipole-dipole interactions and short ranged excluded volume correlations. Minimal energy structures are obtained by numerical optimization procedure as well as analytical considerations. For a small number of constitutive magnets Ntot ≤ 26, a straight chain is found to be the ground state. In the regime of larger Ntot ≥ 27, the magnets form two touching chains with equally long tails at both ends. We succeed to identify the transition from two to three touching chains at Ntot = 129. Overall, this study sheds light on the mechanisms of the recently experimentally observed ribbon formation of superparamagnetic colloids via lateral aggregation of magnetic chains in magnetic field (Darras et al., 2016).

  18. Magnetization of disclinated graphene in nonuniform magnetic field

    NASA Astrophysics Data System (ADS)

    Roshanzamir-Nikou, M.; Goudarzi, H.

    2017-02-01

    Two-dimensional disclinated atomic graphene layer in curved space-time is exactly discussed, and the explicit dependence of Landau levels on the topological defect and external magnetic field are obtained in the presence of nonuniform magnetic field. It is worth mentioning that the presence of topological defect reduces the degeneracy of energy levels. The persistent current, magnetization, susceptibility and the magnetoresistance of structure are investigated. It can be shown that the curvature of the conical surface affects the pattern of oscillations of persistent current and, of course, corresponding magnetoresistance. The behavior of the above physical quantities as a function of magnetic flux is explicitly found for various defects. We observe that increasing magnetic field leads to a aperiodic oscillation. The large Aharonov-Bohm flux gives rise to vanish the magnetization oscillations.

  19. Control of magnetism by electric fields.

    PubMed

    Matsukura, Fumihiro; Tokura, Yoshinori; Ohno, Hideo

    2015-03-01

    The electrical manipulation of magnetism and magnetic properties has been achieved across a number of different material systems. For example, applying an electric field to a ferromagnetic material through an insulator alters its charge-carrier population. In the case of thin films of ferromagnetic semiconductors, this change in carrier density in turn affects the magnetic exchange interaction and magnetic anisotropy; in ferromagnetic metals, it instead changes the Fermi level position at the interface that governs the magnetic anisotropy of the metal. In multiferroics, an applied electric field couples with the magnetization through electrical polarization. This Review summarizes the experimental progress made in the electrical manipulation of magnetization in such materials, discusses our current understanding of the mechanisms, and finally presents the future prospects of the field.

  20. Design of Helical Solenoid Combined with RF Cavity

    SciTech Connect

    Kashikhin, Vladimir; Andreev, Nicolai; Kashikhin, Vadim; Lamm, Michael; Makarov, Alexander; Romanov, Gennady; Yonehara, Katsuya; Yu, Miao; Zlobin, Alexander; /Fermilab

    2010-05-01

    Helical Solenoids (HS) were proposed for a muon beam ionization cooling. There are substantial energy losses, up to 30 MeV/m, during the passing of the muon beam through the absorber. The main issue of such a system is the muon beam energy recovery. A conventional RF cavity is too large to be placed inside HS. In the paper the results of a dielectric-filled RF cavity design is presented. The proposed RF cavity has a helical configuration. Helical Cooling Channel (HCC) module design which includes high pressure vessel, RF cavity, and superconducting HS is presented. The parameters of these module sub-systems are discussed, and the results of muon beam tracking in combined magnetic and electric 3D fields are shown.

  1. Solenoid-based focusing in a proton linac

    SciTech Connect

    Terechkine, I; DiMarco, J.; Schappert, W.; Sergatskov, d.; Tartaglia, M.; /Fermilab

    2010-09-01

    Development of solenoid-based focusing lenses for the transport channel of an R&D linac front end at FNAL (HINS linac) is in its final stage. Superconducting lenses for the room temperature RF section of the linac are assembled into individual cryostats and certified using a dedicated test stand. During this certification process, the optical axis of each lens relative to the cryogenic vessel is found in the warm and cold state. Lenses for the superconducting RF sections are ready for production, and development of a cryomodule (which contains multiple superconducting lenses and RF cavities) is in progress. Studies have been conducted to measure fringe magnetic field of a lens in the cryomodule, to investigate a laser-based method of alignment, and to evaluate the extent of beam quality degradation due to imperfections in lens construction and alignment. This report presents some results of these studies.

  2. Magnetic field evolution of accreting neutron stars

    NASA Astrophysics Data System (ADS)

    Istomin, Y. N.; Semerikov, I. A.

    2016-01-01

    The flow of a matter, accreting on to a magnetized neutron star, is accompanied by an electric current. The closing of the electric current occurs in the crust of a neutron stars in the polar region across the magnetic field. But the conductivity of the crust along the magnetic field greatly exceeds the conductivity across the field, so the current penetrates deep into the crust down up to the superconducting core. The magnetic field, generated by the accretion current, increases greatly with the depth of penetration due to the Hall conductivity of the crust is also much larger than the transverse conductivity. As a result, the current begins to flow mainly in the toroidal direction, creating a strong longitudinal magnetic field, far exceeding an initial dipole field. This field exists only in the narrow polar tube of r width, narrowing with the depth, i.e. with increasing of the crust density ρ, r ∝ ρ-1/4. Accordingly, the magnetic field B in the tube increases with the depth, B∝ρ1/2, and reaches the value of about 1017 Gauss in the core. It destroys superconducting vortices in the core of a star in the narrow region of the size of the order of 10 cm. Because of generated density gradient of vortices, they constantly flow into this dead zone and the number of vortices decreases, the magnetic field of a star decreases as well. The attenuation of the magnetic field is exponential, B = B0(1 + t/τ)-1. The characteristic time of decreasing of the magnetic field τ is equal to τ ≃ 103 yr. Thus, the magnetic field of accreted neutron stars decreases to values of 108-109 Gauss during 107-106 yr.

  3. SQUID-Detected Magnetic Resonance Imaging in MicroteslaFields

    SciTech Connect

    Moessle, Michael; Hatridge, Michael; Clarke, John

    2006-08-14

    Magnetic resonance imaging (MRI) has developed into a powerful clinical tool for imaging the human body (1). This technique is based on nuclear magnetic resonance (NMR) of protons (2, 3) in a static magnetic field B{sub 0}. An applied radiofrequency pulse causes the protons to precess about B{sub 0} at their Larmor frequency {nu}{sub 0} = ({gamma}/2{pi})B{sub 0}, where {gamma} is the gyromagnetic ratio; {gamma}/2{pi} = 42.58 MHz/tesla. The precessing protons generate an oscillating magnetic field and hence a voltage in a nearby coil that is amplified and recorded. The application of three-dimensional magnetic field gradients specifies a unique magnetic field and thus an NMR frequency in each voxel of the subject, so that with appropriate encoding of the signals one can acquire a complete image (4). Most clinical MRI systems involve magnetic fields generated by superconducting magnets, and the current trend is to higher magnetic fields than the widely used 1.5-T systems (5). Nonetheless, there is ongoing interest in the development of less expensive imagers operating at lower fields. Commercially available 0.2-T systems based on permanent magnets offer both lower cost and a more open access than their higher-field counterparts, at the expense of signal-to-noise-ratio (SNR) and spatial resolution. At the still lower field of 0.03 mT maintained by a conventional, room-temperature solenoid, Connolly and co-workers (6, 7) obtain good spatial resolution and signal-to-noise ratio (SNR) by prepolarizing the protons in a field B{sub p} of 0.3 T. Prepolarization (8) enhances the magnetic moment of an ensemble of protons over that produced by the lower precession field; after the polarizing field is removed, the higher magnetic moment produces a correspondingly larger signal during its precession in B{sub 0}. Using the same method, Stepisnik et al. (9) obtained MR images in the Earth's magnetic field ({approx} 50 {micro}T). Alternatively, one can enhance the signal amplitude

  4. Single-layer high field dipole magnets

    SciTech Connect

    Vadim V. Kashikhin and Alexander V. Zlobin

    2001-07-30

    Fermilab is developing high field dipole magnets for post-LHC hadron colliders. Several designs with a nominal field of 10-12 T, coil bore size of 40-50 mm based on both shell-type and block-type coil geometry are currently under consideration. This paper presents a new approach to magnet design, based on simple and robust single-layer coils optimized for the maximum field, good field quality and minimum number of turns.

  5. Two-axis magnetic field sensor

    NASA Technical Reports Server (NTRS)

    Jander, Albrecht (Inventor); Nordman, Catherine A. (Inventor); Qian, Zhenghong (Inventor); Smith, Carl H. (Inventor)

    2006-01-01

    A ferromagnetic thin-film based magnetic field sensor with first and second sensitive direction sensing structures each having a nonmagnetic intermediate layer with two major surfaces on opposite sides thereof having a magnetization reference layer on one and an anisotropic ferromagnetic material sensing layer on the other having a length in a selected length direction and a smaller width perpendicular thereto and parallel to the relatively fixed magnetization direction. The relatively fixed magnetization direction of said magnetization reference layer in each is oriented in substantially parallel to the substrate but substantially perpendicular to that of the other. An annealing process is used to form the desired magnetization directions.

  6. Beginning stages of local magnetic field formation

    NASA Astrophysics Data System (ADS)

    Bumba, V.

    Based on a study of the initial stages of local magnetic field formation, the appearance of a new magnetic flux in the photosphere is studied. This magnetic flux is found to occur both under the influence of different modes of convective motion as well as under the action of Paleomagnetic fields. Waldmeier's Heliographic Maps of the Photosphere and Mt. Wilson Observatory daily magnetic maps were used in the analysis. Observed regularities could not be explained by a model of magnetic flux tubes emerging on the photospheric surface. This model can not account for the practically simultaneous development of separate active regions, belonging to different solar hemispheres and different cycles of solar activity in one, relatively narrow, 'unipolar' sector of the background field. It is also difficult to explain the different roles and velocities of negative and positive polarities during the formation of new magnetic fields. The importance of velocity measurements and maps for solving the observed phenomenon is stressed.

  7. Disruption of coronal magnetic field arcades

    NASA Technical Reports Server (NTRS)

    Mikic, Zoran; Linker, Jon A.

    1994-01-01

    The ideal and resistive properties of isolated large-scale coronal magnetic arcades are studied using axisymmetric solutions of the time-dependent magnetohydrodynamic (MHD) equations in spherical geometry. We examine how flares and coronal mass ejections may be initiated by sudden disruptions of the magnetic field. The evolution of coronal arcades in response to applied shearing photospheric flows indicates that disruptive behavior can occur beyond a critical shear. The disruption can be traced to ideal MHD magnetic nonequilibrium. The magnetic field expands outward in a process that opens the field lines and produces a tangential discontinuity in the magnetic field. In the presence of plasma resistivity, the resulting current sheet is the site of rapid reconnection, leading to an impulsive release of magnetic energy, fast flows, and the ejection of a plasmoid. We relate these results to previous studies of force-free fields and to the properties of the open-field configuration. We show that the field lines in an arcade are forced open when the magnetic energy approaches (but is still below) the open-field energy, creating a partially open field in which most of the field lines extend away from the solar surface. Preliminary application of this model to helmet streamers indicates that it is relevant to the initiation of coronal mass ejections.

  8. Fluctuating magnetic field induced resonant activation

    SciTech Connect

    Mondal, Shrabani; Das, Sudip; Baura, Alendu; Bag, Bidhan Chandra

    2014-12-14

    In this paper, we have studied the properties of a Brownian particle at stationary state in the presence of a fluctuating magnetic field. Time dependence of the field makes the system thermodynamically open. As a signature of that the steady state distribution function becomes function of damping strength, intensity of fluctuations and constant parts of the applied magnetic field. It also depends on the correlation time of the fluctuating magnetic field. Our another observation is that the random magnetic field can induce the resonant activation phenomenon. Here correlation time is increased under the fixed variance of the fluctuating field. But if the correlation time (τ) increases under the fixed field strength then the mean first passage time rapidly grows at low τ and it almost converges at other limit. This is sharp contrast to the usual colored noise driven open system case where the mean first passage time diverges exponentially. We have also observed that a giant enhancement of barrier crossing rate occurs particularly at large strength of constant parts of the applied magnetic field even for very weak fluctuating magnetic field. Finally, break down of the Arrhenius result and disappearance of the Kramers’ turn over phenomenon may occur in the presence of a fluctuating magnetic field.

  9. Interplanetary stream magnetism: Kinematic effects. [solar magnetic fields and wind

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Barouch, E.

    1974-01-01

    The particle density, and the magnetic field intensity and direction are calculated in corotating streams of the solar wind, assuming that the solar wind velocity is constant and radial and that its azimuthal variations are not two rapid. The effects of the radial velocity profile in corotating streams on the magnetic fields were examined using kinematic approximation and a variety of field configurations on the inner boundary. Kinematic and dynamic effects are discussed.

  10. Modeling the evolution of galactic magnetic fields

    SciTech Connect

    Yar-Mukhamedov, D.

    2015-04-15

    An analytic model for evolution of galactic magnetic fields in hierarchical galaxy formation frameworks is introduced. Its major innovative components include explicit and detailed treatment of the physics of merger events, mass gains and losses, gravitational energy sources and delays associated with formation of large-scale magnetic fields. This paper describes the model, its implementation, and core results obtained by its means.

  11. Paramagnetic ellipsoidal microswimmer in a magnetic field

    NASA Astrophysics Data System (ADS)

    Sandoval, Mario; Fan, Louis; Pak, On Shun

    We study the two-dimensional Brownian dynamics of an ellipsoidal paramagnetic microswimmer moving at low-Reynolds-number and subject to a magnetic field. Its corresponding mean-square displacement tensor showing the effect of particles's shape, activity and magnetic field, on the microswimmer's diffusion is analytically obtained. A comparison among analytical and computational results is also made and we obtain excellent agreement.

  12. Solar Magnetic Field: Zeeman and Hanle Effects

    NASA Astrophysics Data System (ADS)

    Stenflo, J.; Murdin, P.

    2001-10-01

    An external magnetic field causes the atomic energy levels to split into different sublevels, and the emitted radiation becomes polarized. This phenomenon is called the ZEEMAN EFFECT. When atoms in a magnetic field scatter radiation via bound-bound transitions, the phase relations or quantum interferences between the Zeeman-split sublevels give rise to POLARIZATION phenomena that go under the nam...

  13. Magnetic fields in Neutron Stars

    NASA Astrophysics Data System (ADS)

    Viganò, D.; Pons, J. A.; Miralles, J. A.; Rea, N.

    2015-05-01

    Isolated neutron stars show a diversity in timing and spectral properties, which has historically led to a classification in different sub-classes. The magnetic field plays a key role in many aspects of the neutron star phenomenology: it regulates the braking torque responsible for their timing properties and, for magnetars, it provides the energy budget for the outburst activity and high quiescent luminosities (usually well above the rotational energy budget). We aim at unifying this observational variety by linking the results of the state-of-the-art 2D magneto-thermal simulations with observational data. The comparison between theory and observations allows to place two strong constraints on the physical properties of the inner crust. First, strong electrical currents must circulate in the crust, rather than in the star core. Second, the innermost part of the crust must be highly resistive, which is in principle in agreement with the presence of a novel phase of matter so-called nuclear pasta phase.

  14. In vivo heating of magnetic nanoparticles in alternating magnetic field.

    PubMed

    Babincová, M; Altanerová, V; Altaner, C; Cicmanec, P; Babinec, P

    2004-08-01

    We have evaluated heating capabilities of new magnetic nanoparticles. In in vitro experiments they were exposed to an alternating magnetic field with frequency 3.5 MHz and induction 1.5 mT produced in three turn pancake coil. In in vivo experiments rats with injected magnetic nanoparticles were also exposed to an ac field. An optimal increase of temperature of the tumor to 44 degrees C was achieved after 10 minutes of exposure. Obtained results showed that magnetic nanoparticles may be easily heated in vitro as well as in vivo, and may be therefore useful for hyperthermic therapy of cancer.

  15. Permanent magnet edge-field quadrupole

    DOEpatents

    Tatchyn, Roman O.

    1997-01-01

    Planar permanent magnet edge-field quadrupoles for use in particle accelerating machines and in insertion devices designed to generate spontaneous or coherent radiation from moving charged particles are disclosed. The invention comprises four magnetized rectangular pieces of permanent magnet material with substantially similar dimensions arranged into two planar arrays situated to generate a field with a substantially dominant quadrupole component in regions close to the device axis.

  16. Ground Vehicle Navigation Using Magnetic Field Variation

    DTIC Science & Technology

    2012-09-13

    65 4.1 Assumptions . . . . . . . . . . . . . . . . . . . . . . . 65 4.1.1 Measurements only in the Body Frame . . . . 65 4.1.2 Changes in the Earth’s...existing information to determine position. Examples include terrain navigation, celestial navigation (astronavigation), inertial navigation, magnetic...tion when the magnetic field measurements are resolved with the body axis, high- lighting magnetic field measurements from magnetometers which do not

  17. Permanent magnet edge-field quadrupole

    DOEpatents

    Tatchyn, R.O.

    1997-01-21

    Planar permanent magnet edge-field quadrupoles for use in particle accelerating machines and in insertion devices designed to generate spontaneous or coherent radiation from moving charged particles are disclosed. The invention comprises four magnetized rectangular pieces of permanent magnet material with substantially similar dimensions arranged into two planar arrays situated to generate a field with a substantially dominant quadrupole component in regions close to the device axis. 10 figs.

  18. Design and characterization of a system for exposure of cultured cells to extremely low frequency electric and magnetic fields over a wide range of field strengths.

    PubMed

    Mullins, R D; Sisken, J E; Hejase, H A; Sisken, B F

    1993-01-01

    A system is described that is capable of producing extremely low frequency (ELF) magnetic fields for relatively short-term exposure of cultured mammalian cells. The system utilizes a ferromagnetic core to contain and direct the magnetic field of a 1,000 turn solenoidal coil and can produce a range of flux densities and induced electric fields much higher than those produced by Helmholtz coils. The system can generate magnetic fields from the microtesla (microT) range up to 0.14 T with induced electric field strengths on the order of 1.0 V/m. The induced electric field can be accurately varied by changing the sample chamber configuration without changing the exposure magnetic field. This gives the system the ability to separate the bioeffects of magnetic and induced electric fields. In the frequency range of 4-100 Hz and magnetic flux density range of 0.005-0.14 T, the maximum total harmonic distortion of the induced electric field is typically less than 1.0%. The temperature of the samples is held constant to within 0.4 degrees C by constant perfusion of warmed culture medium through the sample chamber.

  19. Magnetic Helicity and Large Scale Magnetic Fields: A Primer

    NASA Astrophysics Data System (ADS)

    Blackman, Eric G.

    2015-05-01

    Magnetic fields of laboratory, planetary, stellar, and galactic plasmas commonly exhibit significant order on large temporal or spatial scales compared to the otherwise random motions within the hosting system. Such ordered fields can be measured in the case of planets, stars, and galaxies, or inferred indirectly by the action of their dynamical influence, such as jets. Whether large scale fields are amplified in situ or a remnant from previous stages of an object's history is often debated for objects without a definitive magnetic activity cycle. Magnetic helicity, a measure of twist and linkage of magnetic field lines, is a unifying tool for understanding large scale field evolution for both mechanisms of origin. Its importance stems from its two basic properties: (1) magnetic helicity is typically better conserved than magnetic energy; and (2) the magnetic energy associated with a fixed amount of magnetic helicity is minimized when the system relaxes this helical structure to the largest scale available. Here I discuss how magnetic helicity has come to help us understand the saturation of and sustenance of large scale dynamos, the need for either local or global helicity fluxes to avoid dynamo quenching, and the associated observational consequences. I also discuss how magnetic helicity acts as a hindrance to turbulent diffusion of large scale fields, and thus a helper for fossil remnant large scale field origin models in some contexts. I briefly discuss the connection between large scale fields and accretion disk theory as well. The goal here is to provide a conceptual primer to help the reader efficiently penetrate the literature.

  20. SU-E-J-38: Comparison of 6MV Photon Dose in a Perpendicular and Parallel Magnetic Field

    SciTech Connect

    Ghila, A; Fallone, B; Rathee, S

    2014-06-01

    Purpose: Integrating a linac with an MRI system would allow for real time tumour tracking however the patient will be irradiated in the presence of a magnetic field. The present study experimentally investigates the magnetic field effects on entrance, exit, and interface dose for both transverse and parallel magnetic fields. Methods: Polystyrene was used to construct a set of phantoms for Gafchromic film measurements. One phantom had an adjustable air gap and four other phantoms had one surface at various angles. The linac-MR prototype consisting of a biplanar permanent magnet coupled to a linac was used for the transverse magnetic field measurements. A couple of solenoid electromagnets, stacked on top of each other and irradiated along their bore, were used for the parallel field measurements. Results: All doses are relative to no magnetic field. The transverse magnetic field reduced the entrance dose for all surface angles by strongly deflecting the contaminant electrons. The exit dose in a transverse magnetic field was found to be significantly higher. The entrance dose with a parallel magnetic field present is higher due to the contaminant electrons being concentrated within the beam area. The air gap phantom measurements, done in a transverse magnetic field, show a significant increase of the dose at the proximal side of the air gap and a decrease at the distal side. The measurements, done in the parallel magnetic field, show the concentration of secondary electrons in the air gap. Conclusion: The radiation dose measurements of a 6MV beam in a parallel and transverse magnetic field presented here are currently being replicated using Monte Carlo simulations. This verified Monte Carlo system could provide the dose calculation basis for future linac-MR systems.

  1. Comparing superconducting and permanent magnets for magnetic refrigeration

    NASA Astrophysics Data System (ADS)

    Bjørk, R.; Nielsen, K. K.; Bahl, C. R. H.; Smith, A.; Wulff, A. C.

    2016-05-01

    We compare the cost of a high temperature superconducting (SC) tape-based solenoid with a permanent magnet (PM) Halbach cylinder for magnetic refrigeration. Assuming a five liter active magnetic regenerator volume, the price of each type of magnet is determined as a function of aspect ratio of the regenerator and desired internal magnetic field. It is shown that to produce a 1 T internal field in the regenerator a permanent magnet of hundreds of kilograms is needed or an area of superconducting tape of tens of square meters. The cost of cooling the SC solenoid is shown to be a small fraction of the cost of the SC tape. Assuming a cost of the SC tape of 6000 /m2 and a price of the permanent magnet of 100 /kg, the superconducting solenoid is shown to be a factor of 0.3-3 times more expensive than the permanent magnet, for a desired field from 0.5-1.75 T and the geometrical aspect ratio of the regenerator. This factor decreases for increasing field strength, indicating that the superconducting solenoid could be suitable for high field, large cooling power applications.

  2. Tracing magnetic field orientation in starless cores

    NASA Astrophysics Data System (ADS)

    Maheswar, G.; Ramaprakash, A. N.; Lee, C. W.; Dib, S.

    It is now well understood that stars are formed in the interiors of dense, gravitationally bound molecular cloud cores that are both magnetized and turbulent. But the relative role played by the magnetic field and the turbulence in cloud formation and evolution and in the subsequent star formation is a matter of debate. In a magnetically dominated scenario, the magnetic field geometry of the cores is expected to be inherited unchanged from their low-density envelope, even for an hour glass geometry of the field, unless the action of turbulence disturbs it. We carried out polarimetry of stars projected on starless molecular clouds, LDN 183 and LDN 1544, in R-filter. The comparison of these fields with those in the interiors of the cloud cores inferred from the sub-mm polarization shows that both magnetic field and turbulence are important in the cloud formation and evolution of star formation.

  3. Iron-free detector magnet options for the future circular collider

    NASA Astrophysics Data System (ADS)

    Mentink, Matthias; Dudarev, Alexey; Da Silva, Helder Filipe Pais; Rolando, Gabriella; Cure, Benoit; Gaddi, Andrea; Klyukhin, Vyacheslav; Gerwig, Hubert; Wagner, Udo; ten Kate, Herman

    2016-11-01

    In this paper, several iron-free solenoid-based designs of a detector magnet for the future circular collider for hadron-hadron collisions (FCC-hh) are presented. The detector magnet designs for FCC-hh aim to provide bending power for particles over a wide pseudorapidity range (0 ≤|η |≤4 ). To achieve this goal, the main solenoidal detector magnet is combined with a forward magnet system, such as the previously presented force-and-torque-neutral dipole. Here, a solenoid-based alternative, the so-called balanced forward solenoid, is presented which comprises a larger inner solenoid for providing bending power to particles at |η |≥2.5 , in combination with a smaller balancing coil for ensuring that the net force and torque on each individual coil is minimized. The balanced forward solenoid is compared to the force-and-torque-neutral dipole and advantages and disadvantages are discussed. In addition, several conceptual solenoid-based detector magnet designs are shown, and quantitatively compared. The main difference between these designs is the amount of stray field reduction that is achieved. The main conclusion is that shielding coils can be used to dramatically reduce the stray field, but that this comes at the cost of increased complexity, magnet volume, and magnet weight and reduced affordability.

  4. Chaotic magnetic fields: Particle motion and energization

    SciTech Connect

    Dasgupta, Brahmananda; Ram, Abhay K.; Li, Gang; Li, Xiaocan

    2014-02-11

    Magnetic field line equations correspond to a Hamiltonian dynamical system, so the features of a Hamiltonian systems can easily be adopted for discussing some essential features of magnetic field lines. The integrability of the magnetic field line equations are discussed by various authors and it can be shown that these equations are, in general, not integrable. We demonstrate several examples of realistic chaotic magnetic fields, produced by asymmetric current configurations. Particular examples of chaotic force-free field and non force-free fields are shown. We have studied, for the first time, the motion of a charged particle in chaotic magnetic fields. It is found that the motion of a charged particle in a chaotic magnetic field is not necessarily chaotic. We also showed that charged particles moving in a time-dependent chaotic magnetic field are energized. Such energization processes could play a dominant role in particle energization in several astrophysical environments including solar corona, solar flares and cosmic ray propagation in space.

  5. Influencing the In-flight Shape and Velocity of a Ferrofluid Drop by a Magnetic Field: Case of a Falling Drop Towards a Surface

    NASA Astrophysics Data System (ADS)

    Amirfazli, Alidad; Wu, J. N.; Cabrerizo-Vilchez, Miguel

    2012-11-01

    In this work magnetic field generated either by a solenoid or a permanent magnet was used to manipulate and change the shape of a drop approaching a surface. The magnetic field was also used to change the velocity of the drop approaching the surface. The capability to sculpt the drop shape and change its velocity opens up new ways of manipulating drop impact onto a surface, which can be interesting for printing industry, especially 3D printing for manufacturing parts. EFH1 (Ferrotec, USA), a colloidal dispersion of magnetite in an oil, was used as the ferrofluid, and its drops were generated with a size of ~2.4 mm using a dispensing system. High speed imaging and image processing were the primary tools for this study allowing data acquisition, and analysis, respectively. Results showed that the in-flight drop shape can be changed from spherical (no field applied) to mildly elliptical or even cylindrical depending on the method of magnetic field generation, the strength of the magnetic field, and the duration of application of the magnetic field (when solenoid was used). Drop velocities could also be increased by up to three times of what would have been possible under free fall condition for a drop. Finally a discussion of in-flight drop breakup as an ultimate way to change the drop shape and its potential for applications will be provided.

  6. Formation of magnetically anisotropic composite films at low magnetic fields

    NASA Astrophysics Data System (ADS)

    Ghazi Zahedi, Maryam; Ennen, Inga; Marchi, Sophie; Barthel, Markus J.; Hütten, Andreas; Athanassiou, Athanassia; Fragouli, Despina

    2017-04-01

    We present a straightforward two-step technique for the fabrication of poly (methyl methacrylate) composites with embedded aligned magnetic chains. First, ferromagnetic microwires are realized in a poly (methyl methacrylate) solution by assembling iron nanoparticles in a methyl methacrylate solution under heat in an external magnetic field of 160 mT. The simultaneous thermal polymerization of the monomer throughout the wires is responsible for their permanent linkage and stability. Next, the polymer solution containing the randomly dispersed microwires is casted on a solid substrate in the presence of a low magnetic field (20–40 mT) which induces the final alignment of the microwires into long magnetic chains upon evaporation of the solvent. We prove that the presence of the nanoparticles assembled in the form of microwires is a key factor for the formation of the anisotropic films under low magnetic fields. In fact, such low fields are not capable of driving and assembling dispersed magnetic nanoparticles in the same type of polymer solutions. Hence, this innovative approach can be utilized for the synthesis of magnetically anisotropic nanocomposite films at low magnetic fields.

  7. Design and fabrication of a 30 T superconducting solenoid using overpressure processed Bi2212 round wire

    SciTech Connect

    Flanagan, Gene; Johnson, Rolland

    2016-02-18

    High field superconducting magnets are used in particle colliders, fusion energy devices, and spectrometers for medical imaging and advanced materials research. Magnets capable of generating fields of 20-30 T are needed by future accelerator facilities. A 20-30 T magnet will require the use of high-temperature superconductors (HTS) and therefore the challenges of high field HTS magnet development need to be addressed. Superconducting Bi2Sr2CaCu2Ox (Bi2212) conductors fabricated by the oxide-powder-in-tube (OPIT) technique have demonstrated the capability to carry large critical current density of 105 A/cm2 at 4.2 K and in magnetic fields up to 45 T. Available in round wire multi-filamentary form, Bi2212 may allow fabrication of 20-50 T superconducting magnets. Until recently the performance of Bi2212 has been limited by challenges in realizing high current densities (Jc ) in long lengths. This problem now is solved by the National High Magnetic Field Lab using an overpressure (OP) processing technique, which uses external pressure to process the conductor. OP processing also helps remove the ceramic leakage that results when Bi-2212 liquid leaks out from the sheath material and reacts with insulation, coil forms, and flanges. Significant advances have also been achieved in developing novel insulation materials (TiO2 coating) and Ag-Al sheath materials that have higher mechanical strengths than Ag-0.2wt.% Mg, developing heat treatment approaches to broadening the maximum process temperature window, and developing high-strength, mechanical reinforced Bi-2212 cables. In the Phase I work, we leveraged these new opportunities to prototype overpressure processed solenoids and test them in background fields of up to 14 T. Additionally a design of a fully superconducting 30 T solenoid was produced. This work in conjunction with the future path outlined in the Phase II proposal would

  8. Teaching Representation Translations with Magnetic Field Experiments

    NASA Astrophysics Data System (ADS)

    Tillotson, Wilson Andrew; McCaskey, Timothy; Nasser, Luis

    2017-01-01

    We have developed a laboratory exercise designed to help students translate between different field representations. It starts with students qualitatively mapping field lines for various bar magnet configurations and continues with a Hall probe experiment in which students execute a series of scaffolded tasks, culminating in the prediction and measurement of the spatial variation of magnetic field components along a line near magnets. We describe the experimental tasks, various difficulties students have throughout, and ways this lab makes even their incorrect predictions better. We suggest that developing lab activities of this nature brings a new dimension to the ways students learn and interact with field concepts.

  9. Warm inflation in presence of magnetic fields

    SciTech Connect

    Piccinelli, Gabriella; Ayala, Alejandro; Mizher, Ana Julia

    2013-07-23

    We present preliminary results on the possible effects that primordial magnetic fields can have for a warm inflation scenario, based on global supersymmetry, with a new-inflation-type potential. This work is motivated by two considerations: first, magnetic fields seem to be present in the universe on all scales which rises de possibility that they could also permeate the early universe; second, the recent emergence of inflationary models where the inflaton is not assumed to be isolated but instead it is taken as an interacting field, even during the inflationary expansion. The effects of magnetic fields are included resorting to Schwinger's proper time method.

  10. The magnetic field of ζ Orionis A

    NASA Astrophysics Data System (ADS)

    Blazère, A.; Neiner, C.; Tkachenko, A.; Bouret, J.-C.; Rivinius, Th.

    2015-10-01

    Context. ζ Ori A is a hot star claimed to host a weak magnetic field, but no clear magnetic detection was obtained so far. In addition, it was recently shown to be a binary system composed of a O9.5I supergiant and a B1IV star. Aims: We aim at verifying the presence of a magnetic field in ζ Ori A, identifying to which of the two binary components it belongs (or whether both stars are magnetic), and characterizing the field. Methods: Very high signal-to-noise spectropolarimetric data were obtained with Narval at the Bernard Lyot Telescope (TBL) in France. Archival HEROS, FEROS and UVES spectroscopic data were also used. The data were first disentangled to separate the two components. We then analyzed them with the least-squares deconvolution technique to extract the magnetic information. Results: We confirm that ζ Ori A is magnetic. We find that the supergiant component ζ Ori Aa is the magnetic component: Zeeman signatures are observed and rotational modulation of the longitudinal magnetic field is clearly detected with a period of 6.829 d. This is the only magnetic O supergiant known as of today. With an oblique dipole field model of the Stokes V profiles, we show that the polar field strength is ~140 G. Because the magnetic field is weak and the stellar wind is strong, ζ Ori Aa does not host a centrifugally supported magnetosphere. It may host a dynamical magnetosphere. Its companion ζ Ori Ab does not show any magnetic signature, with an upper limit on the undetected field of ~300 G. Based on observations obtained at the Télescope Bernard Lyot (USR5026) operated by the Observatoire Midi-Pyrénées, Université de Toulouse (Paul Sabatier), Centre National de la Recherche Scientifique of France.Appendix A is available in electronic form at http://www.aanda.org

  11. The Helium Cooling System and Cold Mass Support System for theMICE Coupling Solenoid

    SciTech Connect

    Wang, L.; Wu, H.; Li, L.K.; Green, M.A.; Liu, C.S.; Li, L.Y.; Jia, L.X.; Virostek, S.P.

    2007-08-27

    The MICE cooling channel consists of alternating threeabsorber focus coil module (AFC) and two RF coupling coil module (RFCC)where the process of muon cooling and reacceleration occurs. The RFCCmodule comprises a superconducting coupling solenoid mounted around fourconventional conducting 201.25 MHz closed RF cavities and producing up to2.2T magnetic field on the centerline. The coupling coil magnetic fieldis to produce a low muon beam beta function in order to keep the beamwithin the RF cavities. The magnet is to be built using commercialniobium titanium MRI conductors and cooled by pulse tube coolers thatproduce 1.5 W of cooling capacity at 4.2 K each. A self-centering supportsystem is applied for the coupling magnet cold mass support, which isdesigned to carry a longitudinal force up to 500 kN. This report willdescribe the updated design for the MICE coupling magnet. The cold masssupport system and helium cooling system are discussed indetail.

  12. Magnetic fields in noninvasive brain stimulation.

    PubMed

    Vidal-Dourado, Marcos; Conforto, Adriana Bastos; Caboclo, Luis Otávio Sales Ferreira; Scaff, Milberto; Guilhoto, Laura Maria de Figueiredo Ferreira; Yacubian, Elza Márcia Targas

    2014-04-01

    The idea that magnetic fields could be used therapeutically arose 2000 years ago. These therapeutic possibilities were expanded after the discovery of electromagnetic induction by the Englishman Michael Faraday and the American Joseph Henry. In 1896, Arsène d'Arsonval reported his experience with noninvasive brain magnetic stimulation to the scientific French community. In the second half of the 20th century, changing magnetic fields emerged as a noninvasive tool to study the nervous system and to modulate neural function. In 1985, Barker, Jalinous, and Freeston presented transcranial magnetic stimulation, a relatively focal and painless technique. Transcranial magnetic stimulation has been proposed as a clinical neurophysiology tool and as a potential adjuvant treatment for psychiatric and neurologic conditions. This article aims to contextualize the progress of use of magnetic fields in the history of neuroscience and medical sciences, until 1985.

  13. Sensitivity of magnetic field gradients over Fennoscandia

    NASA Astrophysics Data System (ADS)

    Baykiev, Eldar; Ebbing, Jörg; Brönner, Marco; Fabian, Karl

    2016-04-01

    Magnetic fields from forward calculations of global crustal or lithospheric models cannot be compared easily with spherical harmonic (SH) crustal field models derived from the satellite observations. The reason for this is, that the lithospheric field has a significant part in the low-degree spherical harmonics (n<14) that are dominated by the core field. These low-degree harmonics are commonly zeroed out to retrieve the lithospheric magnetic field. In addition, at satellite height far-field effects from sources outside a regional study affect the long-wavelength part of the magnetic field. Because magnetic field gradients are less sensitive to the long wavelength anomalies, they are also less affected by the far field. However, the gradients still contain information about deep lithospheric structures. We present sensitivity tests based on a synthetic model of the Fennoscandian lithosphere to validate the influence of induced and remanent magnetization in magnetic data at the height of airborne surveys and satellite missions. The use of airborne data and satellite data is complementary because, due to their different height, they are sensitive to different depth domains. To correctly account for global and local aspects of the lithospheric field, our analysis is based on surface discretization by tesseroids (spherical prisms).

  14. INTERSTELLAR MAGNETIC FIELD SURROUNDING THE HELIOPAUSE

    SciTech Connect

    Whang, Y. C.

    2010-02-20

    This paper presents a three-dimensional analytical solution, in the limit of very low plasma beta-ratio, for the distortion of the interstellar magnetic field surrounding the heliopause. The solution is obtained using a line dipole method that is the integration of point dipole along a semi-infinite line; it represents the magnetic field caused by the presence of the heliopause. The solution allows the variation of the undisturbed magnetic field at any inclination angle. The heliosphere is considered as having blunt-nosed geometry on the upwind side and it asymptotically approaches a cylindrical geometry having an open exit for the continuous outflow of the solar wind on the downwind side. The heliopause is treated as a magnetohydrodynamic tangential discontinuity; the interstellar magnetic field lines at the boundary are tangential to the heliopause. The interstellar magnetic field is substantially distorted due to the presence of the heliopause. The solution shows the draping of the field lines around the heliopause. The magnetic field strength varies substantially near the surface of the heliopause. The effect on the magnetic field due to the presence of the heliopause penetrates very deep into the interstellar space; the depth of penetration is of the same order of magnitude as the scale length of the heliosphere.

  15. Dynamic Magnetic Field Applications for Materials Processing

    NASA Technical Reports Server (NTRS)

    Mazuruk, K.; Grugel, Richard N.; Motakef, S.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    Magnetic fields, variable in time and space, can be used to control convection in electrically conducting melts. Flow induced by these fields has been found to be beneficial for crystal growth applications. It allows increased crystal growth rates, and improves homogeneity and quality. Particularly beneficial is the natural convection damping capability of alternating magnetic fields. One well-known example is the rotating magnetic field (RMF) configuration. RMF induces liquid motion consisting of a swirling basic flow and a meridional secondary flow. In addition to crystal growth applications, RMF can also be used for mixing non-homogeneous melts in continuous metal castings. These applied aspects have stimulated increasing research on RMF-induced fluid dynamics. A novel type of magnetic field configuration consisting of an axisymmetric magnetostatic wave, designated the traveling magnetic field (TMF), has been recently proposed. It induces a basic flow in the form of a single vortex. TMF may find use in crystal growth techniques such as the vertical Bridgman (VB), float zone (FZ), and the traveling heater method. In this review, both methods, RMF and TMF are presented. Our recent theoretical and experimental results include such topics as localized TMF, natural convection dumping using TMF in a vertical Bridgman configuration, the traveling heater method, and the Lorentz force induced by TMF as a function of frequency. Experimentally, alloy mixing results, with and without applied TMF, will be presented. Finally, advantages of the traveling magnetic field, in comparison to the more mature rotating magnetic field method, will be discussed.

  16. Protein detection with magnetic nanoparticles in a rotating magnetic field

    NASA Astrophysics Data System (ADS)

    Dieckhoff, Jan; Lak, Aidin; Schilling, Meinhard; Ludwig, Frank

    2014-01-01

    A detection scheme based on magnetic nanoparticle (MNP) dynamics in a rotating magnetic field for a quantitative and easy-to-perform detection of proteins is illustrated. For the measurements, a fluxgate-based setup was applied, which measures the MNP dynamics, while a rotating magnetic field is generated. The MNPs exhibit single iron oxide cores of 25 nm and 40 nm diameter, respectively, as well as a protein G functionalized shell. IgG antibodies were utilized as binding target molecules for the physical proof-of-concept. The measurement results were fitted with a theoretical model describing the magnetization dynamics in a rotating magnetic field. The established detection scheme allows quantitative determination of proteins even at a concentration lower than of the particles. The observed differences between the two MNP types are discussed on the basis of logistic functions.

  17. External-field-free magnetic biosensor

    SciTech Connect

    Li, Yuanpeng; Wang, Yi; Klein, Todd; Wang, Jian-Ping

    2014-03-24

    In this paper, we report a magnetic nanoparticle (MNP) detection scheme without the presence of any external magnetic field. The proposed magnetic sensor uses a patterned groove structure within the sensor so that no external magnetic field is needed to magnetize the MNPs. An example is given based on a giant magnetoresistance (GMR) sensing device with a spin valve structure. For this structure, the detection of MNPs located inside the groove and near the free layer is demonstrated under no external magnetic field. Micromagnetic simulations are performed to calculate the signal to noise level of this detection scheme. A maximum signal to noise ratio (SNR) of 18.6 dB from one iron oxide magnetic nanoparticle with 8 nm radius is achieved. As proof of concept, this external-field-free GMR sensor with groove structure of 200 nm × 200 nm is fabricated using a photo and an electron beam integrated lithography process. Using this sensor, the feasibility demonstration of the detection SNR of 9.3 dB is achieved for 30 μl magnetic nanoparticles suspension (30 nm iron oxide particles, 1 mg/ml). This proposed external-field-free sensor structure is not limited to GMR devices and could be applicable to other magnetic biosensing devices.

  18. The Measurement of Magnetic Fields

    ERIC Educational Resources Information Center

    Berridge, H. J. J.

    1973-01-01

    Discusses five experimental methods used by senior high school students to provide an accurate calibration curve of magnet current against the magnetic flux density produced by an electromagnet. Compares the relative merits of the five methods, both as measurements and from an educational viewpoint. (JR)

  19. Decay of Resonaces in Strong Magnetic Field

    NASA Astrophysics Data System (ADS)

    Filip, Peter

    2015-08-01

    We suggest that decay properties (branching ratios) of hadronic resonances may become modified in strong external magnetic field. The behavior of K±*, K0* vector mesons as well as Λ* (1520) and Ξ0* baryonic states is considered in static fields 1013-1015 T. In particular, n = 0 Landau level energy increase of charged particles in the external magnetic field, and the interaction of hadron magnetic moments with the field is taken into account. We suggest that enhanced yield of dileptons and photons from ρ0(770) mesons may occur if strong decay channel ρ0 → π+π- is significantly suppressed. CP - violating π+π- decays of pseudoscalar ηc and η(547) mesons in the magnetic field are discussed, and superpositions of quarkonium states ηc,b and χc,b(nP) with Ψ(nS), ϒ(nS) mesons in the external field are considered.

  20. Interplanetary magnetic field and geomagnetic Dst variations.

    NASA Technical Reports Server (NTRS)

    Patel, V. L.; Desai, U. D.

    1973-01-01

    The interplanetary magnetic field has been shown to influence the ring current field represented by Dst. Explorer 28 hourly magnetic field observations have been used with the hourly Dst values. The moderate geomagnetic storms of 60 gammas and quiet-time fluctuations of 10 to 30 gammas are correlated with the north to south change of the interplanetary field component perpendicular to the ecliptic. This change in the interplanetary field occurs one to three hours earlier than the corresponding change in the Dst field.

  1. Ohm's law for mean magnetic fields

    SciTech Connect

    Boozer, A.H.

    1984-11-01

    Spatially complicated magnetic fields are frequently treated as the sum of a large, slowly varying, mean field and a small, rapidly varying, field. The primary effect of the small field is to modify the Ohm's law of the mean field. A set of plausible assumptions leads to a form of the mean field Ohm's law which is fundamentally different from the conventional alpha effect of dynamo theory.

  2. Magnetic field homogeneity perturbations in finite Halbach dipole magnets.

    PubMed

    Turek, Krzysztof; Liszkowski, Piotr

    2014-01-01

    Halbach hollow cylinder dipole magnets of a low or relatively low aspect ratio attract considerable attention due to their applications, among others, in compact NMR and MRI systems for investigating small objects. However, a complete mathematical framework for the analysis of magnetic fields in these magnets has been developed only for their infinitely long precursors. In such a case the analysis is reduced to two-dimensions (2D). The paper details the analysis of the 3D magnetic field in the Halbach dipole cylinders of a finite length. The analysis is based on three equations in which the components of the magnetic flux density Bx, By and Bz are expanded to infinite power series of the radial coordinate r. The zeroth term in the series corresponds to a homogeneous magnetic field Bc, which is perturbed by the higher order terms due to a finite magnet length. This set of equations is supplemented with an equation for the field profile B(z) along the magnet axis, presented for the first time. It is demonstrated that the geometrical factors in the coefficients of particular powers of r, defined by intricate integrals are the coefficients of the Taylor expansion of the homogeneity profile (B(z)-Bc)/Bc. As a consequence, the components of B can be easily calculated with an arbitrary accuracy. In order to describe perturbations of the field due to segmentation, two additional equations are borrowed from the 2D theory. It is shown that the 2D approach to the perturbations generated by the segmentation can be applied to the 3D Halbach structures unless r is not too close to the inner radius of the cylinder ri. The mathematical framework presented in the paper was verified with great precision by computations of B by a highly accurate integration of the magnetostatic Coulomb law and utilized to analyze the inhomogeneity of the magnetic field in the magnet with the accuracy better than 1 ppm.

  3. Biological effects of high DC magnetic fields

    SciTech Connect

    Tenforde, T.S.

    1981-06-01

    The principal focus of the program is the analysis of magnetic field effects on physiological functions in experimental animals and selected organ and tissue systems. A major research effort has involved the use of electrical recording techniques to detect functional alterations in the cardiovascular, neural, and visual systems during the application of DC magnetic fields. These systems involve ionic conduction processes, and are therefore potentially sensitive to electrodynamic interactions with an applied magnetic field. In the specific case of the visual system, magnetic interactions could also arise through orientational effects on the magnetically anisotropic photopigment molecules within retinal photoreceptor cells. In addition to studies with potentially sensitive target tissues, an evaluation is being made of magnetic field effects on a broad range of other physiological functions in laboratory mammals, including the measurement of circadian rhythms using noninvasive recording techniques. Results of investigations of magnetic field effects on the conformation of DNA, and on the growth and development of plants and insects are also reported. Figures and tables provide a brief summary of some representative observations in each of the research areas described. No significant alterations were observed in any of the physiological parameters examined to date, with the exception of major changes that occur in the electrocardiogram during magnetic field exposure. Studies with several species of animals have provided evidence that this phenomenon is attributable to electrical potentials that are induced during pulsatile blood flow in the aorta and in other major vessels of the circulatory system.

  4. Vector Magnetic Field in Emerging Flux Regions

    NASA Astrophysics Data System (ADS)

    Schmieder, B.; Pariat, E.

    A crucial phase in magnetic flux emergence is the rise of magnetic flux tubes through the solar photosphere, which represents a severe transition between the very different environments of the solar interior and corona. Multi-wavelength observations with Flare Genesis, TRACE, SoHO, and more recently with the vector magnetographs at THEMIS and Hida (DST) led to the following conclusions. The fragmented magnetic field in the emergence region - with dipped field lines or bald patches - is directly related with Ellerman bombs, arch filament systems, and overlying coronal loops. Measurements of vector magnetic fields have given evidence that undulating "serpentine" fields are present while magnetic flux tubes cross the photosphere. See the sketch below, and for more detail see Pariat et al. (2004, 2007); Watanabe et al. (2008):

  5. Write field asymmetry in perpendicular magnetic recording

    NASA Astrophysics Data System (ADS)

    Li, Zhanjie; Bai, Daniel Z.; Lin, Ed; Mao, Sining

    2012-04-01

    We present a systematic study of write field asymmetry by using micromagnetic modeling for a perpendicular magnetic recording (PMR) writer structure. Parameters investigated include initial magnetization condition, write current amplitude, write current frequency, and initial write current polarity. It is found that the write current amplitude and frequency (data rate) are the dominant factors that impact the field asymmetry. Lower write current amplitude and higher write current frequency will deteriorate the write field asymmetry, causing recording performance (such as bit error rate) degradation.

  6. Surface magnetic fields across the HR Diagram

    NASA Astrophysics Data System (ADS)

    Landstreet, John D.

    2015-10-01

    The past 20 years have seen remarkable advances in spectropolarimetric instrumentation that have allowed us, for the first time, to identify some magnetic stars in most major stages of stellar evolution. We are beginning to see the broad outline of how such fields change during stellar evolution, to confront theoretical hypotheses and models of magnetic field structure and evolution with detailed data, and to understand more of the ways in which the presence of a field in turn affects stellar structure and evolution.

  7. Hyperfine magnetic fields in substituted Finemet alloys

    NASA Astrophysics Data System (ADS)

    Brzózka, K.; Sovák, P.; Szumiata, T.; Gawroński, M.; Górka, B.

    2016-12-01

    Transmission Mössbauer spectroscopy was used to determine the hyperfine fields of Finemet-type alloys in form of ribbons, substituted alternatively by Mn, Ni, Co, Al, Zn, V or Ge of various concentration. The comparative analysis of magnetic hyperfine fields was carried out which enabled to understand the role of added elements in as-quenched as well as annealed samples. Moreover, the influence of the substitution on the mean direction of the local hyperfine magnetic field was examined.

  8. Ohm's law for mean magnetic fields

    SciTech Connect

    Boozer, A.H.

    1986-05-01

    The magnetic fields associated with plasmas frequently exhibit small amplitude MHD fluctuations. It is useful to have equations for the magnetic field averaged over these fluctuations, the so-called mean field equations. Under very general assumptions it is shown that the effect of MHD fluctuations on a force-free plasma can be represented by one parameter in Ohm's law, which is effectively the coefficient of electric current viscosity.

  9. Method to reduce non-specific tissue heating of small animals in solenoid coils

    PubMed Central

    KUMAR, ANANDA; ATTALURI, ANILCHANDRA; MALLIPUDI, RAJIV; CORNEJO, CHRISTINE; BORDELON, DAVID; ARMOUR, MICHAEL; MORUA, KATHERINE; DEWEESE, THEODORE L.; IVKOV, ROBERT

    2014-01-01

    Purpose Solenoid coils that generate time-varying or alternating magnetic fields (AMFs) are used in biomedical devices for research, imaging and therapy. Interactions of AMF and tissue produce eddy currents that deposit power within tissue, thus limiting effectiveness and safety. We aim to develop methods that minimise excess heating of mice exposed to AMFs for cancer therapy experiments. Materials and methods Numerical and experimental data were obtained to characterise thermal management properties of water using a continuous, custom water jacket in a four-turn simple solenoid. Theoretical data were obtained with method-of-moments (MoM) numerical field calculations and finite element method (FEM) thermal simulations. Experimental data were obtained from gel phantoms and mice exposed to AMFs having amplitude >50kA/m and frequency of 160 kHz. Results Water has a high specific heat and thermal conductivity, is diamagnetic, polar, and nearly transparent to magnetic fields. We report at least a two-fold reduction of temperature increase from gel phantom and animal models when a continuous layer of circulating water was placed between the sample and solenoid, compared with no water. Thermal simulations indicate the superior efficiency in thermal management by the developed continuous single chamber cooling system over a double chamber non-continuous system. Further reductions of heating were obtained by regulating water temperature and flow for active cooling. Conclusions These results demonstrate the potential value of a contiguous layer of circulating water to permit sustained exposure to high intensity alternating magnetic fields at this frequency for research using small animal models exposed to AMFs. PMID:23402327

  10. Magnetic fields near Mars - First results

    NASA Technical Reports Server (NTRS)

    Riedler, W.; Schwingenschuh, K.; Moehlmann, D.; Oraevskii, V. N.; Eroshenko, E.; Slavin, J.

    1989-01-01

    The magnetic fields of Mars have been measured from Phobos 2 with high temporal resolution in the tail and down to an 850-km altitude. During four successive highly elliptical orbits, the position of the bow shock as well as that of a transition layer, the 'planetopause', were identified. Subsequent circular orbits at 6000-km altitude provided the first high-resolution data in the planetary tail and indicate that the interplanetary magnetic field mainly controls the magnetic tail. Magnetic turbulence was also detected when the spacecraft crossed the orbit of Phobos, indicating the possible existence of a torus near the orbit of this moon.

  11. Magnetic field reconstruction based on sunspot oscillations

    NASA Astrophysics Data System (ADS)

    Löhner-Böttcher, J.; Bello González, N.; Schmidt, W.

    2016-11-01

    The magnetic field of a sunspot guides magnetohydrodynamic waves toward higher atmospheric layers. In the upper photosphere and lower chromosphere, wave modes with periods longer than the acoustic cut-off period become evanescent. The cut-off period essentially changes due to the atmospheric properties, e.g., increases for larger zenith inclinations of the magnetic field. In this work, we aim at introducing a novel technique of reconstructing the magnetic field inclination on the basis of the dominating wave periods in the sunspot chromosphere and upper photosphere. On 2013 August 21, we observed an isolated, circular sunspot (NOAA11823) for 58 min in a purely spectroscopic multi-wavelength mode with the Interferometric Bidimensional Spectro-polarimeter (IBIS) at the Dunn Solar Telescope. By means of a wavelet power analysis, we retrieved the dominating wave periods and reconstructed the zenith inclinations in the chromosphere and upper photosphere. The results are in good agreement with the lower photospheric HMI magnetograms. The sunspot's magnetic field in the chromosphere inclines from almost vertical (0°) in the umbra to around 60° in the outer penumbra. With increasing altitude in the sunspot atmosphere, the magnetic field of the penumbra becomes less inclined. We conclude that the reconstruction of the magnetic field topology on the basis of sunspot oscillations yields consistent and conclusive results. The technique opens up a new possibility to infer the magnetic field inclination in the solar chromosphere.

  12. Superconducting magnet performance for 28 GHz electron cyclotron resonance ion source developed at the Korea Basic Science Institute

    SciTech Connect

    Park, Jin Yong; Choi, Seyong; Lee, Byoung-Seob; Yoon, Jang-Hee; Ok, Jung-Woo; Shin, Chang Seouk; Won, Mi-Sook; Kim, Byoung Chul; Ahn, Jung Keun

    2014-02-15

    A superconducting magnet for use in an electron cyclotron resonance ion source was developed at the Korea Basic Science Institute. The superconducting magnet is comprised of three solenoids and a hexapole magnet. According to the design value, the solenoid magnets can generate a mirror field, resulting in axial magnetic fields of 3.6 T at the injection area and 2.2 T at the extraction region. A radial field strength of 2.1 T can also be achieved by hexapole magnet on the plasma chamber wall. NbTi superconducting wire was used in the winding process following appropriate techniques for magnet structure. The final assembly of the each magnet involved it being vertically inserted into the cryostat to cool down the temperature using liquid helium. The performance of each solenoid and hexapole magnet was separately verified experimentally. The construction of the superconducting coil, the entire magnet assembly for performance testing and experimental results are reported herein.

  13. Magnetic levitation of condensed hydrogen

    NASA Technical Reports Server (NTRS)

    Paine, C. G.; Seidel, G. M.

    1991-01-01

    Liquid and solid molecular hydrogen has been levitated using a pair of small superconducting solenoids. The hydrogen samples, up to 3 mm in dimension, were trapped in a magnetic potential having either a discrete minimum or a minimum in the form of a ring 1 cm in diameter. The hydrogen could be moved about in the magnetic trap by applying an electric field.

  14. Solenoidal filtering of volumetric velocity measurements using Gaussian process regression

    NASA Astrophysics Data System (ADS)

    Azijli, Iliass; Dwight, Richard P.

    2015-11-01

    Volumetric velocity measurements of incompressible flows contain spurious divergence due to measurement noise, despite mass conservation dictating that the velocity field must be divergence-free (solenoidal). We investigate the use of Gaussian process regression to filter spurious divergence, returning analytically solenoidal velocity fields. We denote the filter solenoidal Gaussian process regression (SGPR) and formulate it within the Bayesian framework to allow a natural inclusion of measurement uncertainty. To enable efficient handling of large data sets on regular and near-regular grids, we propose a solution procedure that exploits the Toeplitz structure of the system matrix. We apply SGPR to two synthetic and two experimental test cases and compare it with two other recently proposed solenoidal filters. For the synthetic test cases, we find that SGPR consistently returns more accurate velocity, vorticity and pressure fields. From the experimental test cases, we draw two important conclusions. Firstly, it is found that including an accurate model for the local measurement uncertainty further improves the accuracy of the velocity field reconstructed with SGPR. Secondly, it is found that all solenoidal filters result in an improved reconstruction of the pressure field, as verified with microphone measurements. The results obtained with SGPR are insensitive to correlation length, demonstrating the robustness of the filter to its parameters.

  15. Magnetic field aberration induced by cycle stress

    NASA Astrophysics Data System (ADS)

    En, Yang; luming, Li; Xing, Chen

    2007-05-01

    Magneto-mechanical effect has been causing people's growing interest because of its relevance to several technology problems. One of them is the variation of surface magnetic field induced by stress concentration under the geomagnetic field. It can be used as an innovative, simple and convenient potential NDE method, called as magnetic memory method. However, whether and how this can be used as a quantitative measurement method, is still a virginal research field where nobody sets foot in. In this paper, circle tensile stress within the elastic region was applied to ferromagnetic sample under geomagnetic field. Experiment results on the relation between surface magnetic field and elastic stress were presented, and a simple model was derived. Simulation of the model was reconciled with the experimental results. This can be of great importance for it provides a brighter future for the promising Magnetic Memory NDE method—the potential possibility of quantitative measurement.

  16. Generation of solar magnetic fields. I. II

    NASA Astrophysics Data System (ADS)

    Parker, E. N.

    Attention is given to those magnetic field properties which allow the fields to destroy themselves rapidly, thereby producing solar, stellar and geomagnetic activity. Magnetic fields actively figure in the production of flares, plages, eruptions and streamers. The existence of magnetic fields in other stars is inferred from the X-rays that can be observed to radiate from them. In the second part of this paper, the discussion in the first part of the generation of magnetic fields from the motion of conducting fluids is further developed through the proposal of the 'short, sudden' idealization, and quick bursts of turbulence during which any degree of twisting and rotation can be accomplished are introduced. After these quick bursts of motion, the fluid is held motionless so that small scale irregularities subside, leaving a smooth, average and large scale state. This cycle is repeated at time intervals tau, producing the dynamo equations for the mean vector potential.

  17. How are static magnetic fields detected biologically?

    NASA Astrophysics Data System (ADS)

    Finegold, Leonard

    2009-03-01

    There is overwhelming evidence that life, from bacteria to birds to bats, detects magnetic fields, using the fields for orientation or navigation. Indeed there are recent reports (based on Google Earth imagery) that cattle and deer align themselves with the earth's magnetic field. [1]. The development of frog and insect eggs are changed by high magnetic fields, probably through known physical mechanisms. However, the mechanisms for eukaryotic navigation and alignment are not clear. Persuasive published models will be discussed. Evidence, that static magnetic fields might produce therapeutic effects, will be updated [2]. [4pt] [1] S. Begall, et al., Proc Natl Acad Sci USA, 105:13451 (2008). [0pt] [2] L. Finegold and B.L. Flamm, BMJ, 332:4 (2006).

  18. The Magnetic Field Geometry of Cool Stars

    NASA Astrophysics Data System (ADS)

    See, Victor; Jardine, Moira; Vidotto, Aline; Donati, Jean-Francois; Folsom, Colin; Boro Saikia, Sudeshna; Bouvier, Jerome; Fares, Rim; Gregory, Scott; Hussain, Gaitee; Jeffers, Sandra; Marsden, Stephen; Morin, Julien; Moutou, Claire; do Nascimento, Jose-Dias, Jr.; Petit, Pascal; Rosen, Lisa; Waite, Ian

    2016-06-01

    Zeeman-Doppler imaging has been used to map the large-scale surface magnetic fields of cool stars across a wide range of stellar masses and rotation periods. The derived field geometries are surprising, with many stars showing strong azimuthal fields that are not observed on the Sun. In this poster, using 100 magnetic maps of over 50 stars, we present results showing how the magnetic field geometry of cool stars varies as a function of fundamental parameters. The stellar mass, and hence internal structure, critically influences the field geometry, although this is modified by the stellar rotation rate. We discuss the implications of these results for dynamo theory and the nature of stellar magnetic activity.

  19. ASYMMETRIC DIFFUSION OF MAGNETIC FIELD LINES

    SciTech Connect

    Beresnyak, Andrey

    2013-04-20

    Stochasticity of magnetic field lines is important for particle transport properties. Magnetic field lines separate faster than diffusively in turbulent plasma, which is called superdiffusion. We discovered that this superdiffusion is pronouncedly asymmetric, so that the separation of field lines along the magnetic field direction is different from the separation in the opposite direction. While the symmetry of the flow is broken by the so-called imbalance or cross-helicity, the difference between forward and backward diffusion is not directly due to imbalance, but a non-trivial consequence of both imbalance and non-reversibility of turbulence. The asymmetric diffusion perpendicular to the mean magnetic field entails a variety of new physical phenomena, such as the production of parallel particle streaming in the presence of perpendicular particle gradients. Such streaming and associated instabilities could be significant for particle transport in laboratory, space, and astrophysical plasmas.

  20. Electric-field guiding of magnetic skyrmions

    NASA Astrophysics Data System (ADS)

    Upadhyaya, Pramey; Yu, Guoqiang; Amiri, Pedram Khalili; Wang, Kang L.

    2015-10-01

    We theoretically study equilibrium and dynamic properties of nanosized magnetic skyrmions in thin magnetic films with broken inversion symmetry, where an electric field couples to magnetization via spin-orbit coupling. Based on a symmetry-based phenomenology and micromagnetic simulations we show that this electric-field coupling, via renormalizing the micromagnetic energy, modifies the equilibrium properties of the skyrmion. This change, in turn, results in a significant alteration of the current-induced skyrmion motion. Particularly, the speed and direction of the skyrmion can be manipulated by designing a desired energy landscape electrically, which we describe within Thiele's analytical model and demonstrate in micromagnetic simulations including electric-field-controlled magnetic anisotropy. We additionally use this electric-field control to construct gates for controlling skyrmion motion exhibiting a transistorlike and multiplexerlike function. The proposed electric-field effect can thus provide a low-energy electrical knob to extend the reach of information processing with skyrmions.

  1. The magnetic field of Mercury, part 1

    NASA Technical Reports Server (NTRS)

    Ness, N. F.; Behannon, K. W.; Lepping, R. P.; Whang, Y. C.

    1974-01-01

    An updated analysis and interpretation is presented of the magnetic field observations obtained during the Mariner 10 encounter with the planet Mercury. The combination of data relating to position of the detached bow shock wave and magnetopause, and the geometry and magnitude of the magnetic field within the magnetosphere-like region surrounding Mercury, lead to the conclusion that an internal planetary field exists with dipole moment approximately 5.1 x 10 the 22nd power Gauss sq cm. The dipole axis has a polarity sense similar to earth's and is tilted 7 deg from the normal to Mercury's orbital plane. The magnetic field observations reveal a significant distortion of the modest Hermean field (350 Gamma at the equator) by the solar wind flow and the formation of a magnetic tail and neutral sheet which begins close to the planet on the night side. The composite data is not consistent with a complex induction process driven by the solar wind flow.

  2. Magnetic field quality analysis using ANSYS

    SciTech Connect

    Dell'Orco, D.; Chen, Y.

    1991-03-01

    The design of superconducting magnets for particles accelerators requires a high quality of the magnetic field. This paper presents an ANSYS 4.4A Post 1 macro that computes the field quality performing a Fourier analysis of the magnetic field. The results show that the ANSYS solution converges toward the analytical solution and that the error on the multipole coefficients depends linearly on the square of the mesh size. This shows the good accuracy of ANSYS in computing the multipole coefficients. 2 refs., 16 figs., 4 tabs.

  3. Ultracold atoms in strong synthetic magnetic fields

    NASA Astrophysics Data System (ADS)

    Ketterle, Wolfgang

    2015-03-01

    The Harper Hofstadter Hamiltonian describes charged particles in the lowest band of a lattice at high magnetic fields. This Hamiltonian can be realized with ultracold atoms using laser assisted tunneling which imprints the same phase into the wavefunction of neutral atoms as a magnetic field dose for electrons. I will describe our observation of a bosonic superfluid in a magnetic field with half a flux quantum per lattice unit cell, and discuss new possibilities for implementing spin-orbit coupling. Work done in collaboration with C.J. Kennedy, G.A. Siviloglou, H. Miyake, W.C. Burton, and Woo Chang Chung.

  4. Relativistic electron in curved magnetic fields

    NASA Technical Reports Server (NTRS)

    An, S.

    1985-01-01

    Making use of the perturbation method based on the nonlinear differential equation theory, the author investigates the classical motion of a relativistic electron in a class of curved magnetic fields which may be written as B=B(O,B sub phi, O) in cylindrical coordinates (R. phi, Z). Under general astrophysical conditions the author derives the analytical expressions of the motion orbit, pitch angle, etc., of the electron in their dependence upon parameters characterizing the magnetic field and electron. The effects of non-zero curvature of magnetic field lines on the motion of electrons and applicabilities of these results to astrophysics are also discussed.

  5. Magnetic-field induced critical endpoint

    NASA Astrophysics Data System (ADS)

    Rechenberger, Stefan

    2017-03-01

    The phase diagram of strong interaction matter is analyzed utilizing the Nambu-Jona-Lasinio model. Special emphasis is placed on its dependence on an external magnetic field and isospin chemical potential. Using flavor mixing induced by instanton effects the influence of isospin breaking due to the magnetic field and the isospin chemical potential is compared. It is found that at low temperatures and large quark chemical potential the magnetic field, depending on its strength, induces a new critical endpoint or a triple point.

  6. Oscillations of Magnetic Fluid Column in Strong Magnetic Field

    NASA Astrophysics Data System (ADS)

    Polunin, V. M.; Storozhenko, A. M.; Platonov, V. B.; Lobova, O. V.; Ryapolov, P. A.

    2017-01-01

    The paper considers the results of measuring the elastic parameters (ponderomotive elasticity coefficient, oscillation frequency, attenuation coefficient) of the oscillatory system with an inertial element that is a magnetic fluid column retained in a tube due to magnetic levitation in a strong magnetic field. Elasticity is provided by the ponderomotive force which affects the upper and lower thin layers of the fluid column. Measurement results of vibration parameters of the oscillatory system can be useful for the investigations of magnetophoresis and aggregation of nanoparticles in magnetic fluids.

  7. Environmental magnetic fields: Influences on early embryogenesis

    SciTech Connect

    Cameron, I.L.; Hardman, W.E.; Winters, W.D.; Zimmerman, S.; Zimmerman, A.M. )

    1993-04-01

    A 10-mG, 50 to 60-Hz magnetic field is in the intensity and frequency range that people worldwide are often exposed to in homes and in the workplace. Studies about the effects of 50- to 100-Hz electromagnetic fields on various species of animal embryos (fish, chick, fly, sea urchin, rat, and mouse) indicate that early stages of embryonic development are responsive to fluctuating magnetic fields. Chick, sea urchin, and mouse embryos are responsive to magnetic field intensities of 10-100 mG. Results from studies on sea urchin embryos indicate that exposure to conditions of rotating 60-Hz magnetic fields, e.g., similar to those in our environment, interferes with cell proliferation at the morula stage in a manner dependent on field intensity. The cleavage stages, prior to the 64-cell stage, were not delayed by this rotating 60-Hz magnetic field suggesting that the ionic surges, DNA replication, and translational events essential for early cleavage stages were not significantly altered. Studies of histone synthesis in early sea urchin embryos indicated that the rotating 60-Hz magnetic field decreased zygotic expression of early histone genes at the morula stage and suggests that this decrease in early histone production was limiting to cell proliferation. Whether these comparative observations from animal development studies will be paralleled by results from studies of human embryogenesis, as suggested by some epidemiology studies, has yet to be established. 38 refs.

  8. Formation of field-reversed ion rings in a magnetized background plasma

    SciTech Connect

    Omelchenko, Y.A.; Sudan, R.N.

    1995-07-01

    In typical field-reversed ion ring experiments, an intense annular ion beam is injected across a magnetic cusp into neutral gas immersed in a solenoidal magnetic field. In anticipation of a new experimental thrust to create strong field-reversed ion rings the beam evolution is investigated in a preformed background plasma on a time scale greater than an ion cyclotron period, using a new two and a half-dimensional (21/2-D) hybrid, particle-in-cell (PIC) code FIRE, in which the beam and background ions are treated as macro-particles and the electrons as a massless fluid. It is shown that under appropriate conditions axial beam bunching occurs in the downstream applied field and a compact field-reversed ring is formed. It is observed that the ring is reflected in a ramped magnetic field. Upon reflection its axial velocity is very much less than that expected from a single particle model due to the transfer of the mean axial momentum to the background ions. This increases the time available to apply a pulsed mirror for trapping the ring experimentally. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  9. Discharge rate measurements for Micromegas detectors in the presence of a longitudinal magnetic field

    SciTech Connect

    B. Moreno, S. Aune, J. Ball, G. Charles, A. Giganon, P. Konczykowski, C. Lahonde-Hamdoun, H. Moutarde, S. Procureur, F. Sabatie

    2011-10-01

    We present first discharge rate measurements for Micromegas detectors in the presence of a high longitudinal magnetic field in the GeV kinematical region. Measurements were performed by using two Micromegas detectors and a photon beam impinging a CH{sub 2} target in the Hall B of the Jefferson Laboratory. One detector was equipped with an additional GEM foil, and a reduction of the discharge probability by two orders of magnitude compared to the stand-alone Micromegas was observed. The detectors were p laced in the FROST solenoid providing a longitudinal magnetic field up to 5T. It allowed for precise measurements of the discharge probability dependence with a diffusion-reducing magnetic field. Between 0 and 5T, the discharge probability increased by a factor of 10 for polar angles between 19{degrees} and 34{degrees}. A GEANT4-based simulation developed for sparking rate calculation was calibrated against these data in order to predict the sparking rate in a high longitudinal magnetic field environment. This simulati on is then used to investigate the possible use of Micromegas in the Forward Vertex Tracker (FVT) of the future CLAS12 spectrometer. In the case of the FVT a sparking rate of 1Hz per detector was obtained at the anticipated CLAS12 luminosity.

  10. Reversals of the Earth's Magnetic Field

    NASA Astrophysics Data System (ADS)

    Champion, Duene E.

    J.A. Jacobs of Cambridge University has written a concise, authoritative, and up-todate text on reversals of the earth's magnetic field. Chapter 1 is a concise summary of the basic attributes of the geomagnetic field and its behavior in different time frames. It explains spherical harmonic analysis of the field and presents the history of acquisition of the data that best represent the recent field. Lastly, it includes a short summary of the origin and electrodynamics of the magnetic field, outlining the current theoretical basis for its generation.

  11. Dynamo Models for Saturn's Axisymmetric Magnetic Field

    NASA Astrophysics Data System (ADS)

    Stanley, S.; Tajdaran, K.

    2012-12-01

    Magnetic field measurements by the Cassini mission have confirmed the earlier Pioneer 11 and Voyager missions' results that Saturn's observed magnetic field is extremely axisymmetric . For example, Saturn's dipole tilt is less than 0.06 degrees (Cao et al., 2011) . The nearly-perfect axisymmetry of Saturn's dipole is troubling because of Cowling's Theorem which states that an axisymmetric magnetic field cannot be maintained by a dynamo. However, Cowling's Theorem applies to the magnetic field generated inside the dynamo source region and we can avert any contradiction with Cowling's Theorem if we can find reason for a non-axisymmetric field generated inside the dynamo region to have an axisymmetrized potential field observed at satellite altitude. Stevenson (1980) proposed a mechanism for this axisymmetrization. He suggested that differential rotation in a stably-stratified electrically conducting layer (i.e. the helium rain-out layer) surrounding the dynamo could act to shear out the non-axisymmetry and hence produce an axisymmetric observed magnetic field. In previous work, we used three-dimensional self-consistent numerical dynamo models to demonstrate that a thin helium rain-out layer can produce a more axisymmetrized field (Stanley, 2010). We also found that the direction of the zonal flows in the layer is a crucial factor for magnetic field axisymmetry. Here we investigate the influence of the thickness of the helium rain-out layer and the intensity of the thermal winds on the axisymmetrization of the field. We search for optimal regions in parameter space for producing axisymmetric magnetic fields with similar spectral properties to the observed Saturnian field.

  12. Space applications of superconductivity - High field magnets

    NASA Technical Reports Server (NTRS)

    Fickett, F. R.

    1979-01-01

    The paper discusses developments in superconducting magnets and their applications in space technology. Superconducting magnets are characterized by high fields (to 15T and higher) and high current densities combined with low mass and small size. The superconducting materials and coil design are being improved and new high-strength composites are being used for magnet structural components. Such problems as maintaining low cooling temperatures (near 4 K) for long periods of time and degradation of existing high-field superconductors at low strain levels can be remedied by research and engineering. Some of the proposed space applications of superconducting magnets include: cosmic ray analysis with magnetic spectrometers, energy storage and conversion, energy generation by magnetohydrodynamic and thermonuclear fusion techniques, and propulsion. Several operational superconducting magnet systems are detailed.

  13. Directed Plasma Flow across Magnetic Field

    NASA Astrophysics Data System (ADS)

    Presura, R.; Stepanenko, Y.; Neff, S.; Sotnikov, V. I.

    2008-04-01

    The Hall effect plays a significant role in the penetration of plasma flows across magnetic field. For example, its effect may become dominant in the solar wind penetration into the magnetosphere, in the magnetic field advection in wire array z-pinch precursors, or in the arcing of magnetically insulated transmission lines. An experiment performed at the Nevada Terawatt Facility explored the penetration of plasma with large Hall parameter (˜10) across ambient magnetic field. The plasma was produced by ablation with the short pulse high intensity laser Leopard (0.35 ps, 10^17W/cm^2) and the magnetic field with the pulsed power generator Zebra (50 T). The expanding plasma assumed a jet configuration and propagated beyond a distance consistent with a diamagnetic bubble model. Without magnetic field, the plasma expansion was close to hemispherical. The ability to produce the plasma and the magnetic field with distinct generators allows a controlled, quasi-continuous variation of the Hall parameter and other plasma parameters making the experiments useful for benchmarking numerical simulations.

  14. Effect of magnetic field inhomogeneity on ion cyclotron motion coherence at high magnetic field.

    PubMed

    Vladimirov, Gleb; Kostyukevich, Yury; Hendrickson, Christopher L; Blakney, Greg T; Nikolaev, Eugene

    2015-01-01

    A three-dimensional code based on the particle-in-cell algorithm modified to account for the inhomogeneity of the magnetic field was applied to determine the effect of Z(1), Z(2), Z(3), Z(4), X, Y, ZX, ZY, XZ(2) YZ(2), XY and X(2)-Y(2) components of an orthogonal magnetic field expansion on ion motion during detection in an FT-ICR cell. Simulations were performed for magnetic field strengths of 4.7, 7, 14.5 and 21 Tesla, including experimentally determined magnetic field spatial distributions for existing 4.7 T and 14.5 T magnets. The effect of magnetic field inhomogeneity on ion cloud stabilization ("ion condensation") at high numbers of ions was investigated by direct simulations of individual ion trajectories. Z(1), Z(2), Z(3) and Z(4) components have the largest effect (especially Z(1)) on ion cloud stability. Higher magnetic field strength and lower m/z demand higher relative magnetic field homogeneity to maintain cloud coherence for a fixed time period. The dependence of mass resolving power upper limit on Z(1) inhomogeneity is evaluated for different magnetic fields and m/z. The results serve to set the homogeneity requirements for various orthogonal magnetic field components (shims) for future FT-ICR magnet design.

  15. Inductive sustainment of oblate field-reversed configurations with the assistance of magnetic diffusion, shaping, and finite-Larmor radius stabilization

    SciTech Connect

    Gerhardt, S. P.; Belova, E. V.; Yamada, M.; Ji, H.; Jacobson, C. M.; McGeehan, B.; Ren, Y.; Inomoto, M.; Maqueda, R.

    2008-02-15

    Oblate field-reversed configurations (FRCs) have been sustained for >300 {mu}s, or >15 magnetic diffusion times, through the use of an inductive solenoid. These argon FRCs can have their poloidal flux sustained or increased, depending on the timing and strength of the induction. An inward pinch is observed during sustainment, leading to a peaking of the pressure profile and maintenance of the FRC equilibrium. The good stability observed in argon (and krypton) does not transfer to lighter gases, which develop terminal co-interchange instabilities. The stability in argon and krypton is attributed to a combination of external field shaping, magnetic diffusion, and finite-Larmor radius effects.

  16. High Field Pulse Magnets with New Materials

    NASA Astrophysics Data System (ADS)

    Li, L.; Lesch, B.; Cochran, V. G.; Eyssa, Y.; Tozer, S.; Mielke, C. H.; Rickel, D.; van Sciver, S. W.; Schneider-Muntau, H. J.

    2004-11-01

    High performance pulse magnets using the combination of CuNb conductor and Zylon fiber composite reinforcement with bore sizes of 24, 15 and 10 mm have been designed, manufactured and tested to destruction. The magnets successfully reached the peak fields of 64, 70 and 77.8 T respectively with no destruction. Failures occurred near the end flanges at the layer. The magnet design, manufacturing and testing, and the mode of the failure are described and analyzed.

  17. Magnetic monopoles in field theory and cosmology.

    PubMed

    Rajantie, Arttu

    2012-12-28

    The existence of magnetic monopoles is predicted by many theories of particle physics beyond the standard model. However, in spite of extensive searches, there is no experimental or observational sign of them. I review the role of magnetic monopoles in quantum field theory and discuss their implications for particle physics and cosmology. I also highlight their differences and similarities with monopoles found in frustrated magnetic systems.

  18. Compact Electric- And Magnetic-Field Sensor

    NASA Technical Reports Server (NTRS)

    Winterhalter, Daniel; Smith, Edward

    1994-01-01

    Compact sensor measures both electric and magnetic fields. Includes both short electric-field dipole and search-coil magnetometer. Three mounted orthogonally providing triaxial measurements of electromagnetic field at frequencies ranging from near 0 to about 10 kHz.

  19. Design and modeling of magnetically driven electric-field sensor for non-contact DC voltage measurement in electric power systems

    NASA Astrophysics Data System (ADS)

    Wang, Decai; Li, Ping; Wen, Yumei

    2016-10-01

    In this paper, the design and modeling of a magnetically driven electric-field sensor for non-contact DC voltage measurement are presented. The magnetic drive structure of the sensor is composed of a small solenoid and a cantilever beam with a cylindrical magnet mounted on it. The interaction of the magnet and the solenoid provides the magnetic driving force for the sensor. Employing magnetic drive structure brings the benefits of low driving voltage and large vibrating displacement, which consequently results in less interference from the drive signal. In the theoretical analyses, the capacitance calculation model between the wire and the sensing electrode is built. The expression of the magnetic driving force is derived by the method of linear fitting. The dynamical model of the magnetic-driven cantilever beam actuator is built by using Euler-Bernoulli theory and distributed parameter method. Taking advantage of the theoretical model, the output voltage of proposed sensor can be predicted. The experimental results are in good agreement with the theoretical results. The proposed sensor shows a favorable linear response characteristic. The proposed sensor has a measuring sensitivity of 9.87 μV/(V/m) at an excitation current of 37.5 mA. The electric field intensity resolution can reach 10.13 V/m.

  20. Computer Calculations of Eddy-Current Power Loss in Rotating Titanium Wheels and Rims in Localized Axial Magnetic Fields

    SciTech Connect

    Mayhall, D J; Stein, W; Gronberg, J B

    2006-05-15

    We have performed preliminary computer-based, transient, magnetostatic calculations of the eddy-current power loss in rotating titanium-alloy and aluminum wheels and wheel rims in the predominantly axially-directed, steady magnetic fields of two small, solenoidal coils. These calculations have been undertaken to assess the eddy-current power loss in various possible International Linear Collider (ILC) positron target wheels. They have also been done to validate the simulation code module against known results published in the literature. The commercially available software package used in these calculations is the Maxwell 3D, Version 10, Transient Module from the Ansoft Corporation.

  1. Constraints on primordial magnetic fields from inflation

    SciTech Connect

    Green, Daniel; Kobayashi, Takeshi E-mail: takeshi.kobayashi@sissa.it

    2016-03-01

    We present generic bounds on magnetic fields produced from cosmic inflation. By investigating field bounds on the vector potential, we constrain both the quantum mechanical production of magnetic fields and their classical growth in a model independent way. For classical growth, we show that only if the reheating temperature is as low as T{sub reh} ∼< 10{sup 2} MeV can magnetic fields of 10{sup −15} G be produced on Mpc scales in the present universe. For purely quantum mechanical scenarios, even stronger constraints are derived. Our bounds on classical and quantum mechanical scenarios apply to generic theories of inflationary magnetogenesis with a two-derivative time kinetic term for the vector potential. In both cases, the magnetic field strength is limited by the gravitational back-reaction of the electric fields that are produced simultaneously. As an example of quantum mechanical scenarios, we construct vector field theories whose time diffeomorphisms are spontaneously broken, and explore magnetic field generation in theories with a variable speed of light. Transitions of quantum vector field fluctuations into classical fluctuations are also analyzed in the examples.

  2. MRS photodiode in strong magnetic field

    SciTech Connect

    Beznosko, D.; Blazey, G.; Dyshkant, A.; Francis, K.; Kubik, D.; Rykalin, V.; Tartaglia, M.A.; Zutshi, v.; /Northern Illinois U.

    2004-12-01

    The experimental results on the performance of the MRS (Metal/Resistor/Semiconductor) photodiode in the strong magnetic field of 4.4T, and the possible impact of the quench of the magnet at 4.5T on sensor's operation are reported.

  3. Ultrafast precessional magnetization reversal by picosecond magnetic field pulse shaping

    NASA Astrophysics Data System (ADS)

    Gerrits, Th.; van den Berg, H. A. M.; Hohlfeld, J.; Bär, L.; Rasing, Th.

    2002-08-01

    Since the invention of the first magnetic memory disk in 1954, much effort has been put into enhancing the speed, bit density and reliability of magnetic memory devices. In the case of magnetic random access memory (MRAM) devices, fast coherent magnetization rotation by precession of the entire memory cell is desired, because reversal by domain-wall motion is much too slow. In principle, the fundamental limit of the switching speed via precession is given by half of the precession period. However, under-critically damped systems exhibit severe ringing and simulations show that, as a consequence, undesired back-switching of magnetic elements of an MRAM can easily be initiated by subsequent write pulses, threatening data integrity. We present a method to reverse the magnetization in under-critically damped systems by coherent rotation of the magnetization while avoiding any ringing. This is achieved by applying specifically shaped magnetic field pulses that match the intrinsic properties of the magnetic elements. We demonstrate, by probing all three magnetization components, that reliable precessional reversal in lithographically structured micrometre-sized elliptical permalloy elements is possible at switching times of about 200ps, which is ten times faster than the natural damping time constant.

  4. Wire codes, magnetic fields, and childhood cancer

    SciTech Connect

    Kheifets, L.I.; Kavet, R.; Sussman, S.S.

    1997-05-01

    Childhood cancer has been modestly associated with wire codes, an exposure surrogate for power frequency magnetic fields, but less consistently with measured fields. The authors analyzed data on the population distribution of wire codes and their relationship with several measured magnetic field metrics. In a given geographic area, there is a marked trend for decreased prevalence from low to high wire code categories, but there are differences between areas. For average measured fields, there is a positive relationship between the mean of the distributions and wire codes but a large overlap among the categories. Better discrimination is obtained for the extremes of the measurement values when comparing the highest and the lowest wire code categories. Instability of measurements, intermittent fields, or other exposure conditions do not appear to provide a viable explanation for the differences between wire codes and magnetic fields with respect to the strength and consistency of their respective association with childhood cancer.

  5. Topology of Saturn's main magnetic field

    NASA Astrophysics Data System (ADS)

    Acuna, M. H.; Connerney, J. E. P.; Ness, N. F.

    1981-08-01

    The reported analysis of Saturn's main magnetic field takes into account the data obtained by Voyager 1 during its close flyby of Saturn in November 1980. A magnetic field model for the analysis of Saturn's main field in which the distributed ring currents are explicitly modelled is constructed. The considered internal field parameters constitute a first approximation to Saturn's main field. Several model current systems that might be expected on physical grounds to be active in Saturn's magnetosphere are considered. It is pointed out that certain aspects of Saturn's main magnetic field relevant to the planet's interior have been discussed by Stevenson (1980). In particular, the unexpectedly small dipole moment seems to be consistent with the gravitational settling of helium, which leads to a much smaller electrically conducting and convecting region than would be expected of a homogeneous distribution of hydrogen and helium.

  6. Effect of a magnetic field on sonoluminescence.

    PubMed

    Yasui, K

    1999-08-01

    The effect of a magnetic field on single-bubble sonoluminescence in water reported experimentally by Young, Schmiedel, and Kang [Phys. Rev. Lett. 77, 4816 (1996)] is studied theoretically. It is suggested that bubble dynamics is affected by the magnetic field because moving water molecules of the liquid suffer torque due to the Lorentz force acting on their electrical dipole moment, which results in the transformation of some of the kinetic energy into heat. It is shown that the magnetic field acts as if the ambient pressure of the liquid were increased. It is suggested that the effect increases as the amount of the liquid water increases. It is predicted that nonpolar liquid such as dodecane exhibits no effect of the magnetic field.

  7. 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.

  8. 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.

  9. Fractal structure of the interplanetary magnetic field

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Klein, L. W.

    1985-01-01

    Under some conditions, time series of the interplanetary magnetic field strength and components have the properties of fractal curves. Magnetic field measurements made near 8.5 AU by Voyager 2 from June 5 to August 24, 1981 were self-similar over time scales from approximately 20 sec to approximately 3 x 100,000 sec, and the fractal dimension of the time series of the strength and components of the magnetic field was D = 5/3, corresponding to a power spectrum P(f) approximately f sup -5/3. Since the Kolmogorov spectrum for homogeneous, isotropic, stationary turbulence is also f sup -5/3, the Voyager 2 measurements are consistent with the observation of an inertial range of turbulence extending over approximately four decades in frequency. Interaction regions probably contributed most of the power in this interval. As an example, one interaction region is discussed in which the magnetic field had a fractal dimension D = 5/3.

  10. The Magnetic Field of Helmholtz Coils

    ERIC Educational Resources Information Center

    Berridge, H. J. J.

    1975-01-01

    Describes the magnetic field of Helmholtz coils qualitatively and then provides the basis for a quantitative expression. Since the mathematical calculations are very involved, a computer program for solving the mathematical expression is presented and explained. (GS)

  11. High-Field Superconducting Magnets Supporting PTOLEMY

    NASA Astrophysics Data System (ADS)

    Hopkins, Ann; Luo, Audrey; Osherson, Benjamin; Gentile, Charles; Tully, Chris; Cohen, Adam

    2013-10-01

    The Princeton Tritium Observatory for Light, Early Universe, Massive Neutrino Yield (PTOLEMY) is an experiment planned to collect data on Big Bang relic neutrinos, which are predicted to be amongst the oldest and smallest particles in the universe. Currently, a proof-of-principle prototype is being developed at Princeton Plasma Physics Laboratory to test key technologies associated with the experiment. A prominent technology in the experiment is the Magnetic Adiabatic Collimation with an Electrostatic Filter (MAC-E filter), which guides tritium betas along magnetic field lines generated by superconducting magnets while deflecting those of lower energies. B field mapping is performed to ensure the magnets produce a minimum field at the midpoint of the configuration of the magnets and to verify accuracy of existing models. Preliminary tests indicate the required rapid decrease in B field strength from the bore of the more powerful 3.35 T magnet, with the field dropping to 0.18 T approximately 0.5 feet from the outermost surface of the magnet.

  12. Laminated magnet field coil sheath

    DOEpatents

    Skaritka, John R.

    1987-12-01

    a method for manufacturing a magnet cable trim coil in a sheath assembly for use in a cryogenic particle accelerator. A precisely positioned pattern of trim coil turns is bonded to a flexible substrate sheath that is capable of withstanding cryogenic operating conditions. In the method of the invention the flexible sheath, with the trim coil pattern precisely positioned thereon, is accurately positioned at a precise location relative to a bore tube assembly of an accelerator and is then bonded to the bore tube with a tape suitable for cryogenic application. The resultant assembly can be readily handled and installed within an iron magnet yoke assembly of a suitable cryogenic particle accelerator.

  13. Laminated magnet field coil sheath

    DOEpatents

    Skaritka, J.R.

    1987-05-15

    A method for manufacturing a magnetic cable trim coil in a sheath assembly for use in a cryogenic particle accelerator. A precisely positioned pattern of trim coil turns is bonded to a flexible substrate sheath that is capable of withstanding cryogenic operating conditions. In the method of the invention the flexible substrate sheath, with the trim coil pattern precisely location relative to a bore tube assembly of an accelerator and is then bonded to the bore tube with a tape suitable for cryogenic application. The resultant assembly can be readily handled and installed within an iron magnet yoke assembly of a suitable cryogenic particle accelerator. 1 fig.

  14. Magnetic Field Effect on the Stability of Flow Induced by a Rotating Magnetic Field

    NASA Technical Reports Server (NTRS)

    Mazuruk, K.; Volz, M. P.; Gillies, D. C.

    1999-01-01

    A linear stability analysis has been performed for the flow induced by a rotating magnetic field in a cylindrical column filled with electrically conducting fluid. The first transition is time- independent and results in the generation of Taylor vortices. The critical value of the magnetic Taylor number has been examined as a function of the strength of the transverse rotating magnetic field, the strength of an axial static magnetic field, and thermal buoyancy. Increasing the transverse field increases the critical magnetic Taylor number and decreases the aspect ratio of the Taylor vortices at the onset of instability. An increase in the axial magnetic field also increases the critical magnetic Taylor number but increases the aspect ratio of the Taylor vortices. Thermal buoyancy is found to have only a negligible effect on the onset of instability.

  15. Magnetic Field Effect on the Stability of Flow Induced by a Rotating Magnetic Field

    NASA Technical Reports Server (NTRS)

    Mazuruk, K.; Gillies, D. C.; Volz, M. P.

    1999-01-01

    A linear stability analysis has been performed for the flow induced by a rotating magnetic field in a cylindrical column filled with electrically conducting fluid. The first transition is time-independent and results in the generation of Taylor vortices. The critical value of the magnetic Taylor number has been examined as a function of the strength of the transverse rotating magnetic field, the strength of an axial static magnetic field, and thermal buoyancy. Increasing the transverse field increases the critical magnetic Taylor number and decreases the aspect ratio of the Taylor vortices at the onset of instability. An increase in the axial magnetic field also increases the critical magnetic Taylor number but increases the aspect ratio of the Taylor vortices. Thermal buoyancy is found to have only a negligible effect on the onset of instability.

  16. Growing Magnetic Fields in Central Compact Objects

    NASA Astrophysics Data System (ADS)

    Bernal, C. G.; Page, D.

    2011-10-01

    We study the effects of growth models of magnetic fields in Central Compact Objects (CCOs). Such a field evolution is not a new idea (Blandford, Applegate, & Hernquist 1983) but the evolutionary implications not have been followed up completely (Michel 1994). We discussed the new class of neutron stars which belong to five main types that have mainly been recognized in the last ten years. The possibility that a rapid weakly magnetized pulsar might have formed in SN1987A is commented.

  17. The magnetic field investigation on Cluster

    NASA Technical Reports Server (NTRS)

    Balogh, A.; Cowley, S. W. H.; Southwood, D. J.; Musmann, G.; Luhr, H.; Neubauer, F. M.; Glassmeier, K.-H.; Riedler, W.; Heyn, M. F.; Acuna, M. H.

    1988-01-01

    The magnetic field investigation of the Cluster four-spacecraft mission is designed to provide intercalibrated measurements of the B magnetic field vector. The instrumentation and data processing of the mission are discussed. The instrumentation is identical on the four spacecraft. It consists of two triaxial fluxgate sensors and of a failure tolerant data processing unit. The combined analysis of the four spacecraft data will yield such parameters as the current density vector, wave vectors, and the geometry and structure of discontinuities.

  18. Magnetic fields and massive star formation

    SciTech Connect

    Zhang, Qizhou; Keto, Eric; Ho, Paul T. P.; Ching, Tao-Chung; Chen, How-Huan; Qiu, Keping; Girart, Josep M.; Juárez, Carmen; Liu, Hauyu; Tang, Ya-Wen; Koch, Patrick M.; Rao, Ramprasad; Lai, Shih-Ping; Li, Zhi-Yun; Frau, Pau; Li, Hua-Bai; Padovani, Marco; Bontemps, Sylvain

    2014-09-10

    Massive stars (M > 8 M {sub ☉}) typically form in parsec-scale molecular clumps that collapse and fragment, leading to the birth of a cluster of stellar objects. We investigate the role of magnetic fields in this process through dust polarization at 870 μm obtained with the Submillimeter Array (SMA). The SMA observations reveal polarization at scales of ≲0.1 pc. The polarization pattern in these objects ranges from ordered hour-glass configurations to more chaotic distributions. By comparing the SMA data with the single dish data at parsec scales, we found that magnetic fields at dense core scales are either aligned within 40° of or perpendicular to the parsec-scale magnetic fields. This finding indicates that magnetic fields play an important role during the collapse and fragmentation of massive molecular clumps and the formation of dense cores. We further compare magnetic fields in dense cores with the major axis of molecular outflows. Despite a limited number of outflows, we found that the outflow axis appears to be randomly oriented with respect to the magnetic field in the core. This result suggests that at the scale of accretion disks (≲ 10{sup 3} AU), angular momentum and dynamic interactions possibly due to close binary or multiple systems dominate over magnetic fields. With this unprecedentedly large sample of massive clumps, we argue on a statistical basis that magnetic fields play an important role during the formation of dense cores at spatial scales of 0.01-0.1 pc in the context of massive star and cluster star formation.

  19. Numerical analysis of modified Central Solenoid insert design

    DOE PAGES

    Khodak, Andrei; Martovetsky, Nicolai; Smirnov, Aleksandre; ...

    2015-06-21

    The United States ITER Project Office (USIPO) is responsible for fabrication of the Central Solenoid (CS) for ITER project. The ITER machine is currently under construction by seven parties in Cadarache, France. The CS Insert (CSI) project should provide a verification of the conductor performance in relevant conditions of temperature, field, currents and mechanical strain. The US IPO designed the CSI that will be tested at the Central Solenoid Model Coil (CSMC) Test Facility at JAEA, Naka. To validate the modified design we performed three-dimensional numerical simulations using coupled solver for simultaneous structural, thermal and electromagnetic analysis. Thermal and electromagneticmore » simulations supported structural calculations providing necessary loads and strains. According to current analysis design of the modified coil satisfies ITER magnet structural design criteria for the following conditions: (1) room temperature, no current, (2) temperature 4K, no current, (3) temperature 4K, current 60 kA direct charge, and (4) temperature 4K, current 60 kA reverse charge. Fatigue life assessment analysis is performed for the alternating conditions of: temperature 4K, no current, and temperature 4K, current 45 kA direct charge. Results of fatigue analysis show that parts of the coil assembly can be qualified for up to 1 million cycles. Distributions of the Current Sharing Temperature (TCS) in the superconductor were obtained from numerical results using parameterization of the critical surface in the form similar to that proposed for ITER. Lastly, special ADPL scripts were developed for ANSYS allowing one-dimensional representation of TCS along the cable, as well as three-dimensional fields of TCS in superconductor material. Published by Elsevier B.V.« less

  20. Numerical analysis of modified Central Solenoid insert design

    SciTech Connect

    Khodak, Andrei; Martovetsky, Nicolai; Smirnov, Aleksandre; Titus, Peter

    2015-06-21

    The United States ITER Project Office (USIPO) is responsible for fabrication of the Central Solenoid (CS) for ITER project. The ITER machine is currently under construction by seven parties in Cadarache, France. The CS Insert (CSI) project should provide a verification of the conductor performance in relevant conditions of temperature, field, currents and mechanical strain. The US IPO designed the CSI that will be tested at the Central Solenoid Model Coil (CSMC) Test Facility at JAEA, Naka. To validate the modified design we performed three-dimensional numerical simulations using coupled solver for simultaneous structural, thermal and electromagnetic analysis. Thermal and electromagnetic simulations supported structural calculations providing necessary loads and strains. According to current analysis design of the modified coil satisfies ITER magnet structural design criteria for the following conditions: (1) room temperature, no current, (2) temperature 4K, no current, (3) temperature 4K, current 60 kA direct charge, and (4) temperature 4K, current 60 kA reverse charge. Fatigue life assessment analysis is performed for the alternating conditions of: temperature 4K, no current, and temperature 4K, current 45 kA direct charge. Results of fatigue analysis show that parts of the coil assembly can be qualified for up to 1 million cycles. Distributions of the Current Sharing Temperature (TCS) in the superconductor were obtained from numerical results using parameterization of the critical surface in the form similar to that proposed for ITER. Lastly, special ADPL scripts were developed for ANSYS allowing one-dimensional representation of TCS along the cable, as well as three-dimensional fields of TCS in superconductor material. Published by Elsevier B.V.

  1. Untwisting magnetic fields in the solar corona

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Ramit; Smolarkiewicz, Piotr; Chye Low, Boon

    2012-07-01

    The solar corona is the tenuous atmosphere of the Sun characterized by a temperature of the order of million degrees Kelvin, an ambient magnetic field of 10 to 15 Gauss and a very high magnetic Reynolds number because of which it qualifies as a near-ideal magnetofluid system. It is well known that for such a system, the magnetic flux across every fluid surface remains effectively constant to a good approximation. Under this so called ``frozen-in'' condition then, it is possible to partition this magnetofluid into contiguous magnetic subvolumes each entrapping its own subsystem of magnetic flux. Thin magnetic flux tubes are an elementary example of such magnetic subvolumes evolving in time with no exchange of fluid among them. The internal twists and interweaving of these flux tubes, collectively referred as the magnetic topology, remains conserved under the frozen-in condition. Because of the dynamical evolution of the magnetofluid, two such subvolumes can come into direct contact with each other by expelling a third interstitial subvolume. In this process, the magnetic field may become discontinuous across the surface of contact by forming a current sheet there. Because of the small spatial scales generated by steepening of magnetic field gradient, the otherwise negligible resistivity becomes dominant and allows for reconnection of field lines which converts magnetic energy into heat. This phenomenon of spontaneous current sheet formation and its subsequent resistive decay is believed to be a possible mechanism for heating the solar corona to its million degree Kelvin temperature. In this work the dynamics of spontaneous current sheet formation is explored through numerical simulations and the results are presented.

  2. Cosmic Magnetic Fields: Observations and Prospects

    NASA Astrophysics Data System (ADS)

    Beck, Rainer

    2011-09-01

    Synchrotron emission, its polarization and its Faraday rotation at radio frequencies of 0.2-10 GHz are powerful tools to study the strength and structure of cosmic magnetic fields. Unpolarized emission traces turbulent fields which are strongest in galactic spiral arms and bars (20-30 μG) and in central starburst regions (50-100 μG). Such fields are dynamically important, e.g. they can drive gas inflows in central regions. Polarized emission traces ordered fields which can be regular (uni-directional) or anisotropic random (generated from isotropic random fields by compression or shear). Ordered fields with spiral patterns exist in grand-design, barred and flocculent galaxies, and in central regions of starburst galaxies. The strongest ordered (mostly regular) fields of 10-15 μG strength are generally found in galactic interarm regions and follow the orientation of adjacent gas spiral arms. Faraday rotation measures (RM) of the diffuse polarized radio emission from the disks of several spiral galaxies reveal large-scale patterns, which are signatures of regular fields probably generated by a mean-field dynamo. Ordered fields in interacting galaxies have asymmetric distributions and are an excellent tracer of past interactions between galaxies or with the intergalactic medium. Ordered magnetic fields are also observed in radio halos around edge-on galaxies, out to large distances from the plane, with X-shaped patterns.--The strength of the total magnetic field in our Milky Way is about 6 μG near the solar radius, but several mG in dense clouds, pulsar wind nebulae, and filaments near the Galactic Center. Diffuse polarized radio emission and Faraday rotation data from pulsars and background sources show spiral fields with large-scale reversals, but the overall field structure in our Galaxy is still under debate.--Diffuse radio emission from the halos of galaxy clusters is mostly unpolarized because intracluster magnetic fields are turbulent, while cluster

  3. The magnetic field of a permanent hollow cylindrical magnet

    NASA Astrophysics Data System (ADS)

    Reich, Felix A.; Stahn, Oliver; Müller, Wolfgang H.

    2016-09-01

    Based on the rational version of M AXWELL's equations according to T RUESDELL and T OUPIN or KOVETZ, cf. (Kovetz in Electromagnetic theory, Oxford University Press, Oxford, 2000; Truesdell and Toupin in Handbuch der Physik, Bd. III/1, Springer, Berlin, pp 226-793; appendix, pp 794-858, 2000), we present, for stationary processes, a closed-form solution for the magnetic flux density of a hollow cylindrical magnet. Its magnetization is constant in axial direction. We consider M AXWELL's equations in regular and singular points that are obtained by rational electrodynamics, adapted to stationary processes. The magnetic flux density is calculated analytically by means of a vector potential. We obtain a solution in terms of complete elliptic integrals. Therefore, numerical evaluation can be performed in a computationally efficient manner. The solution is written in dimensionless form and can easily be applied to cylinders of arbitrary shape. The relation between the magnetic flux density and the magnetic field is linear, and an explicit relation for the field is presented. With a slight modification the result can be used to obtain the field of a solid cylindrical magnet. The mathematical structure of the solution and, in particular, singularities are discussed.

  4. 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.

  5. Electric and magnetic fields in cryopreservation.

    PubMed

    Wowk, Brian

    2012-06-01

    Electromagnetic warming has a long history in cryobiology as a preferred method for recovering large tissue masses from cryopreservation, especially from cryopreservation by vitrification. It is less well-known that electromagnetic fields may be able to influence ice formation during cryopreservation by non-thermal mechanisms. Both theory and published data suggest that static and oscillating electric fields can respectively promote or inhibit ice formation under certain conditions. Evidence is less persuasive for magnetic fields. Recent claims that static magnetic fields smaller than 1 mT can improve cryopreservation by freezing are specifically questioned.

  6. Magnetic field transfer device and method

    DOEpatents

    Wipf, S.L.

    1990-02-13

    A magnetic field transfer device includes a pair of oppositely wound inner coils which each include at least one winding around an inner coil axis, and an outer coil which includes at least one winding around an outer coil axis. The windings may be formed of superconductors. The axes of the two inner coils are parallel and laterally spaced from each other so that the inner coils are positioned in side-by-side relation. The outer coil is outwardly positioned from the inner coils and rotatable relative to the inner coils about a rotational axis substantially perpendicular to the inner coil axes to generate a hypothetical surface which substantially encloses the inner coils. The outer coil rotates relative to the inner coils between a first position in which the outer coil axis is substantially parallel to the inner coil axes and the outer coil augments the magnetic field formed in one of the inner coils, and a second position 180[degree] from the first position, in which the augmented magnetic field is transferred into the other inner coil and reoriented 180[degree] from the original magnetic field. The magnetic field transfer device allows a magnetic field to be transferred between volumes with negligible work being required to rotate the outer coil with respect to the inner coils. 16 figs.

  7. Magnetic field transfer device and method

    DOEpatents

    Wipf, Stefan L.

    1990-01-01

    A magnetic field transfer device includes a pair of oppositely wound inner coils which each include at least one winding around an inner coil axis, and an outer coil which includes at least one winding around an outer coil axis. The windings may be formed of superconductors. The axes of the two inner coils are parallel and laterally spaced from each other so that the inner coils are positioned in side-by-side relation. The outer coil is outwardly positioned from the inner coils and rotatable relative to the inner coils about a rotational axis substantially perpendicular to the inner coil axes to generate a hypothetical surface which substantially encloses the inner coils. The outer coil rotates relative to the inner coils between a first position in which the outer coil axis is substantially parallel to the inner coil axes and the outer coil augments the magnetic field formed in one of the inner coils, and a second position 180.degree. from the first position, in which the augmented magnetic field is transferred into the other inner coil and reoriented 180.degree. from the original magnetic field. The magnetic field transfer device allows a magnetic field to be transferred between volumes with negligible work being required to rotate the outer coil with respect to the inner coils.

  8. Magnetic field amplification in turbulent astrophysical plasmas

    NASA Astrophysics Data System (ADS)

    Federrath, Christoph

    2016-12-01

    Magnetic fields play an important role in astrophysical accretion discs and in the interstellar and intergalactic medium. They drive jets, suppress fragmentation in star-forming clouds and can have a significant impact on the accretion rate of stars. However, the exact amplification mechanisms of cosmic magnetic fields remain relatively poorly understood. Here, I start by reviewing recent advances in the numerical and theoretical modelling of the turbulent dynamo, which may explain the origin of galactic and intergalactic magnetic fields. While dynamo action was previously investigated in great detail for incompressible plasmas, I here place particular emphasis on highly compressible astrophysical plasmas, which are characterised by strong density fluctuations and shocks, such as the interstellar medium. I find that dynamo action works not only in subsonic plasmas, but also in highly supersonic, compressible plasmas, as well as for low and high magnetic Prandtl numbers. I further present new numerical simulations from which I determine the growth of the turbulent (un-ordered) magnetic field component ( turb$ ) in the presence of weak and strong guide fields ( 0$ ). I vary 0$ over five orders of magnitude and find that the dependence of turb$ on 0$ is relatively weak, and can be explained with a simple theoretical model in which the turbulence provides the energy to amplify turb$ . Finally, I discuss some important implications of magnetic fields for the structure of accretion discs, the launching of jets and the star-formation rate of interstellar clouds.

  9. Measurement of the magnetic field coefficients of particle accelerator magnets

    SciTech Connect

    Herrera, J.; Ganetis, G.; Hogue, R.; Rogers, E.; Wanderer, P.; Willen, E.

    1989-01-01

    An important aspect in the development of magnets to be used in particle accelerators is the measurement of the magnetic field in the beam aperture. In general it is necessary to measure the harmonic multipoles in the dipole, quadrupole, and sextupole magnets for a series of stationary currents (plateaus). This is the case for the Superconducting Super Collider (SSC) which will be ramped to high field over a long period (/approximately/1000 sec.) and then remain on the flat top for the duration of the particle collision phase. In contrast to this mode of operation, the Booster ring being constructed for the Brookhaven AGS, will have a fast ramp rate of approximately 10 Hz. The multipole fields for these Booster magnets must therefore be determined ''on the ramp.'' In this way the effect of eddy currents will be taken into account. The measurement system which we will describe in this paper is an outgrowth of that used for the SSC dipoles. It has the capability of measuring the field multipoles on both a plateau or during a fast ramp. In addition, the same basic coil assembly is used to obtain the magnetic multipoles in dipole, quadrupole, and sextupole magnets. 2 refs., 3 figs., 1 tab.

  10. Experimental Investigation of Electron Cloud Containment in a Nonuniform Magnetic Field

    NASA Technical Reports Server (NTRS)

    Eninger, J. E.

    1974-01-01

    Dense clouds of electrons were generated and studied in an axisymmetric, nonuniform magnetic field created by a short solenoid. The operation of the experiment was similar to that of a low-pressure (approximately 0.000001 Torr) magnetron discharge. Discharge current characteristics are presented as a function of pressure, magnetic field strength, voltage, and cathode end-plate location. The rotation of the electron cloud is determined from the frequency of diocotron waves. In the space charge saturated regime of operation, the cloud is found to rotate as a solid body with frequency close to V sub a/phi sub a where V sub a is the anode voltage and phi suba is the total magnetic flux. This result indicates that, in regions where electrons are present, the magnetic field lines are electrostatic equipotentials (E bar, B bar = 0). Equilibrium electron density distributions suggested by this conditions are integrated with respect to total ionizing power and are found consistent with measured discharge currents.

  11. Influence of magnetic domain walls and magnetic field on the thermal conductivity of magnetic nanowires.

    PubMed

    Huang, Hao-Ting; Lai, Mei-Feng; Hou, Yun-Fang; Wei, Zung-Hang

    2015-05-13

    We investigated the influence of magnetic domain walls and magnetic fields on the thermal conductivity of suspended magnetic nanowires. The thermal conductivity of the nanowires was obtained using steady-state Joule heating to measure the change in resistance caused by spontaneous heating. The results showed that the thermal conductivity coefficients of straight and wavy magnetic nanowires decreased with an increase in the magnetic domain wall number, implying that the scattering between magnons and domain walls hindered the heat transport process. In addition, we proved that the magnetic field considerably reduced the thermal conductivity of a magnetic nanowire. The influence of magnetic domain walls and magnetic fields on the thermal conductivity of polycrystalline magnetic nanowires can be attributed to the scattering of long-wavelength spin waves mediated by intergrain exchange coupling.

  12. Investigations of Magnetically Enhanced RIE Reactors with Rotating Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Babaeva, Natalia Yu.; Kushner, Mark J.

    2008-10-01

    In Magnetically Enhanced Reactive Ion Etching (MERIE) reactors, a magnetic field parallel to the substrate enables higher plasma densities and control of ion energy distributions. Since it is difficult to make the B-field uniform across the wafer, the B-field is often azimuthally rotated at a few Hz to average out non-uniformities. The rotation is slow enough that the plasma is in quasi-equilibrium with the instantaneous B-field. For the pressures (10's mTorr or less) and B-fields (10's - 100's G) of interest, electrons are magnetized whereas ions are usually not. The orientation and intersection of the B-field with the wafer are important, as intersecting field lines provide a low resistance path for electron current to the substrate. We report on a modeling study of plasma properties in MERIE reactors having rotating B-fields by investigating a series of quasi-steady states of B-field profiles. To resolve side-to-side variations, computations are performed in Cartesian coordinates. The model, nonPDPSIM, was improved with full tensor conductivities in the fluid portions of the code and v x B forces in the kinetic portions. Results are discussed while varying the orientation and strength of the B-field for electropositive (argon) and electronegative (Ar/CxFy, Ar/Cl2) gas mixtures.

  13. Magnetic Field Apparatus (MFA) Hardware Test

    NASA Technical Reports Server (NTRS)

    Anderson, Ken; Boody, April; Reed, Dave; Wang, Chung; Stuckey, Bob; Cox, Dave

    1999-01-01

    The objectives of this study are threefold: (1) Provide insight into water delivery in microgravity and determine optimal germination paper wetting for subsequent seed germination in microgravity; (2) Observe the behavior of water exposed to a strong localized magnetic field in microgravity; and (3) Simulate the flow of fixative (using water) through the hardware. The Magnetic Field Apparatus (MFA) is a new piece of hardware slated to fly on the Space Shuttle in early 2001. MFA is designed to expose plant tissue to magnets in a microgravity environment, deliver water to the plant tissue, record photographic images of plant tissue, and deliver fixative to the plant tissue.

  14. Effects of static magnetic fields on plants.

    NASA Astrophysics Data System (ADS)

    Kuznetsov, O.

    In our recent experiment on STS-107 (MFA-Biotube) we took advantage of the magnetic heterogeneity of the gravity receptor cells of flax roots, namely stronger diamagnetism of starch-filled amyloplasts compared to cytoplasm (Δ ≊ < 0). High gradient magnetic fields (HGMF, grad(H2/2) up to 109-1010 Oe2/cm) of the experimental chambers (MFCs) repelled amyloplasts from the zones of stronger field thus providing a directional stimulus for plant gravisensing system in microgravity, and causing the roots to react. Such reaction was observed in the video downlink pictures. Unfortunately, the ``Columbia'' tragedy caused loss of the plant material and most of the images, thus preventing us from detailed studies of the results. Currently we are looking for a possibility to repeat this experiment. Therefore, it is very important to understand, what other effects (besides displacing amyloplasts) static magnetic fields with intensities 0 to 2.5104 Oe, and with the size of the area of non-uniformity 10-3 to 1 cm. These effects were estimated theoretically and tested experimentally. No statistically significant differences in growth rates or rates of gravicurvature were observed in experiments with Linum, Arabidopsis, Hordeum, Avena, Ceratodon and Chara between the plants grown in uniform magnetic fields of various intensities (102 to 2.5104 Oe) and those grown in the Earth's magnetic field. Microscopic studies also did not detect any structural differences between test and control plants. The magnitudes of possible effects of static magnetic fields on plant cells and organs (including effects on ion currents, magneto-hydrodynamic effects in moving cytoplasm, ponderomotive forces on other cellular structures, effects on some biochemical reactions and biomolecules) were estimated theoretically. The estimations have shown, that these effects are small compared to the thermodynamic noise and thus are insignificant. Both theoretical estimations and control experiments confirm, that

  15. Fast Reconnection of Weak Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Zweibel, Ellen G.

    1998-01-01

    Fast magnetic reconnection refers to annihilation or topological rearrangement of magnetic fields on a timescale that is independent (or nearly independent) of the plasma resistivity. The resistivity of astrophysical plasmas is so low that reconnection is of little practical interest unless it is fast. Yet, the theory of fast magnetic reconnection is on uncertain ground, as models must avoid the tendency of magnetic fields to pile up at the reconnection layer, slowing down the flow. In this paper it is shown that these problems can be avoided to some extent if the flow is three dimensional. On the other hand, it is shown that in the limited but important case of incompressible stagnation point flows, every flow will amplify most magnetic fields. Although examples of fast magnetic reconnection abound, a weak, disordered magnetic field embedded in stagnation point flow will in general be amplified, and should eventually modify the flow. These results support recent arguments against the operation of turbulent resistivity in highly conducting fluids.

  16. Critical Magnetic Field Determination of Superconducting Materials

    SciTech Connect

    Canabal, A.; Tajima, T.; Dolgashev, V.A.; Tantawi, S.G.; Yamamoto, T.; /Tsukuba, Natl. Res. Lab. Metrol.

    2011-11-04

    Superconducting RF technology is becoming more and more important. With some recent cavity test results showing close to or even higher than the critical magnetic field of 170-180 mT that had been considered a limit, it is very important to develop a way to correctly measure the critical magnetic field (H{sup RF}{sub c}) of superconductors in the RF regime. Using a 11.4 GHz, 50-MW, <1 {mu}s, pulsed power source and a TE013-like mode copper cavity, we have been measuring critical magnetic fields of superconductors for accelerator cavity applications. This device can eliminate both thermal and field emission effects due to a short pulse and no electric field at the sample surface. A model of the system is presented in this paper along with a discussion of preliminary experimental data.

  17. Thomson scattering in a magnetic field. II - Arbitrary field orientation

    NASA Technical Reports Server (NTRS)

    Whitney, Barbara A.

    1991-01-01

    This paper presents solutions to the equation of transfer for Thomson scattering in a constant magnetic field of arbitrary orientation. Results from several atmospheres are combined to give the flux from a dipole star. The results are compared to the polarization data of the magnetic white dwarf Grw + 70 deg 8247. The fit is good, though it implies a very large polarization in the ultraviolet. Thomson scattering is not thought to be an important opacity source in white dwarfs, so the good fit is either fortuitous or is perhaps explained by assuming the magnetic field affects the polarization processes in all opacities similarly.

  18. Magnetic fields in Local Group dwarf irregulars

    NASA Astrophysics Data System (ADS)

    Chyży, K. T.; Weżgowiec, M.; Beck, R.; Bomans, D. J.

    2011-05-01

    Aims: We wish to clarify whether strong magnetic fields can be effectively generated in typically low-mass dwarf galaxies and to assess the role of dwarf galaxies in the magnetization of the Universe. Methods: We performed a search for radio emission and magnetic fields in an unbiased sample of 12 Local Group (LG) irregular and dwarf irregular galaxies with the 100-m Effelsberg telescope at 2.64 GHz. Three galaxies were detected. A higher frequency (4.85 GHz) was used to search for polarized emission in five dwarfs that are the most luminous ones in the infrared domain, of which three were detected. Results: Magnetic fields in LG dwarfs are weak, with a mean value of the total field strength of <4.2 ± 1.8 μG, three times lower than in the normal spirals. The strongest field among all LG dwarfs of 10 μG (at 2.64 GHz) is observed in the starburst dwarf IC 10. The production of total magnetic fields in dwarf systems appears to be regulated mainly by the star-formation surface density (with the power-law exponent of 0.30 ± 0.04) or by the gas surface density (with the exponent 0.47 ± 0.09). In addition, we find systematically stronger fields in objects of higher global star-formation rate. The dwarf galaxies follow a similar far-infrared relationship (with a slope of 0.91 ± 0.08) to that determined for high surface brightness spiral galaxies. The magnetic field strength in dwarf galaxies does not correlate with their maximum rotational velocity, indicating that a small-scale rather than a large-scale dynamo process is responsible for producting magnetic fields in dwarfs. If magnetization of the Universe by galactic outflows is coeval with its metal enrichment, we show that more massive objects (such as Lyman break galaxies) can efficiently magnetize the intergalactic medium with a magnetic field strength of about 0.8 nG out to a distance of 160-530 kpc at redshifts 5-3, respectively. Magnetic fields that are several times weaker and shorter magnetization

  19. 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.

  20. New isolated gate bipolar transistor two-quadrant chopper power supply for a fast field cycling nuclear magnetic resonance spectrometer

    NASA Astrophysics Data System (ADS)

    Sousa, D. M.; Marques, G. D.; Sebastião, P. J.; Ribeiro, A. C.

    2003-10-01

    This work, presents, for the first time, an Isolated Gate Bipolar Transistor (IGBT) two-quadrant chopper power supply for a fast field cycling (FFC) nuclear magnetic resonance spectrometer. This power supply was designed to achieve a maximum current of 200 A with good efficiency, low semiconductor losses, low cost, and easy maintenance. Both energy storage circuits and dumping circuits are used to obtain switching times less than 2 ms between field levels in agreement with the FFC technique specifications. The current ripple at high currents is better than 1×10-4 and presents a specific shape which can be used for additional compensation using auxiliary circuits. The implemented power supply was tested and been continuously operating with a home-built FFC solenoidal magnet, associated cooling system, and rf units for fields between 0 and 0.2 T.