IEEE Transactions on Magnetics

Volume 25 Issue 1 • Jan. 1989

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Displaying Results 1 - 25 of 131
  • Electromagnetic launch technology: the promise and the problems

    Publication Year: 1989, Page(s):17 - 19
    Cited by:  Papers (14)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (287 KB)

    The state of electromagnetic launcher technology is briefly reviewed. Technical problems in achieving the launch technology objectives are discussed, including those connected with energy storage devices, switching devices, rails and solenoid accelerators, and the effects of high acceleration on projectiles and impact physics. Finally, the state of the materials technology is considered, and the a... View full abstract»

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  • Review of impact fusion concepts (EM launchers)

    Publication Year: 1989, Page(s):20 - 26
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (490 KB)

    The authors review the main features of the impact fusion concept in which gram-sized metallic projectiles from electromagnetic launchers collide around heavy-hydrogen fusile gas to produce thermonuclear plasma whose pressure brings the projectiles to rest, providing a pulse of fusion power during the 'turnaround' of the projectiles. They discuss the concepts of nonmagnetic as well as magnetically... View full abstract»

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  • The performance of new, redesigned ignitron tubes in axial magnetic fields

    Publication Year: 1989, Page(s):27 - 32
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (663 KB)

    The test results from two special ignitron tubes exposed to axial magnetic fields are described. The experiments were made using a capacitor bank with 2.56 mF total capacitance and 128 kJ maximum energy at 10 kV. To study the effects of axial magnetic fields on the switching characteristics, including the self-breakdown voltage of the tubes, the test specimens were mounted inside four high-power, ... View full abstract»

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  • Friction and ablation measurements in a round bore railgun

    Publication Year: 1989, Page(s):33 - 39
    Cited by:  Papers (24)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (520 KB)

    Detailed experiments were performed in order to determine electrode ablation and friction effects in a round-bore railgun. An accelerating model was developed which includes electrode-ablation effects, the viscous arc drag, and the mechanical friction of the projectile. In addition, a novel nonlinear electrode-ablation model was found to describe the experimental data very well. A model for the me... View full abstract»

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  • Explosive opening switch work at Westinghouse

    Publication Year: 1989, Page(s):40 - 45
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (582 KB)

    An explosive switch that commutated 315 kA into a resistor and a second version designed to switch up to 1 MA into an HPG (homopolar generator) -driven railgun system are presented. These switches are located very near the load and consist of a set of main busbars in a low-inductance configuration shorted by a thinner switch busbar. Linear-shaped charges are used to sever this switch busbar at sev... View full abstract»

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  • Continuous measurements of in-bore projectile velocity

    Publication Year: 1989, Page(s):46 - 51
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (508 KB)

    The application of velocity interferometry to the continuous measurement of in-bore projectile velocity in a small-bore three-stage railgun is described. These measurements are useful for determining projectile acceleration and for evaluating gun performance. The launcher used in these studies consists of a two-stage light gas gun used to inject projectiles into a railgun for additional accelerati... View full abstract»

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  • The use of finite element analysis techniques for solving rail gun problems

    Publication Year: 1989, Page(s):52 - 56
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (275 KB)

    The use of commercial electromagnetic finite-element programs for solving railgun problems such as inductance calculations, force evaluations, and current-density distributions is described. The first code considered, PE2D, is a program for solving the electromagnetic and electrostatic problems described by the Laplace, Poisson, Helmholz or diffusion equations in two dimensions. PE2D is limited in... View full abstract»

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  • United Kingdom EM gun programme

    Publication Year: 1989, Page(s):57 - 62
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (537 KB)

    The authors review the progress in the RARDE (Royal Armament Research and Development Establishment) electromagnetic gun (REMGUN) program. They cover research on both railgun and LIA (linear induction accelerator) technology, including work on modeling, projectile/barrel interactions armatures, switching, and instrumentation. They also describe the major research facilities. Progress is reported i... View full abstract»

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  • A finite-element method for the prediction of joule heating of conductors in electromagnetic launchers

    Publication Year: 1989, Page(s):63 - 67
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (332 KB)

    The authors describe a method based on a magnetic vector potential development for calculating the joule heating of the conductors in arbitrary launcher geometries. The method accounts for the effects of varying conductivity of the launcher's materials and can be implemented using available two-dimensional finite-element diffusion codes. Conductor temperature distributions as functions of time for... View full abstract»

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  • Advances in opening switch technology at IAP research

    Publication Year: 1989, Page(s):68 - 71
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (383 KB)

    The author describes some advances in opening switch technology and their demonstration in the megampere advanced switch technology (MAST) hardware. After describing the MAST concept, he examines the efficiency, weight, and life characteristics of the switch. He concludes that the MAST switch demonstrates the feasibility of large-bore rapid-fire railgun systems based on inductive energy storage.<<... View full abstract»

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  • High velocity contact properties

    Publication Year: 1989, Page(s):72 - 74
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (216 KB)

    It is noted that electrical contacts have not been experimentally investigated at velocities above a few hundred meters per second. The authors describe a ballistic technique which can be used to measure friction coefficient and contact resistance at velocities up to several kilometers per second (i.e. at railgun armature operating conditions). The theoretical basis of the technique is described, ... View full abstract»

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  • Resistive commutation at megampere current levels

    Publication Year: 1989, Page(s):75 - 78
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (343 KB)

    A method of resistive commutation at megampere current levels is examined. Arcing commutation at these current levels causes excessive erosion of current collectors. Resistive commutation substantially eliminates arcing and erosion. Laboratory tests were conducted in which repetitive, resistive commutation at currents up to 700 kA was demonstrated. A significant reduction in arcing and collector d... View full abstract»

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  • The mechanical design of armatures

    Publication Year: 1989, Page(s):79 - 82
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (330 KB)

    The authors describe a mechanical design approach for metal armatures which is based on preventing contact arcing. The minimum pressure required to prevent arcing is combined with the mechanical characteristics of the armature to define its safe operating envelope. The design goal is to provide an envelope which will permit armature operation over the range of current and armature deflection expec... View full abstract»

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  • Railgun rail gouging by hypervelocity sliding contact

    Publication Year: 1989, Page(s):83 - 87
    Cited by:  Papers (18)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (413 KB)

    A description is given of a recently resolved mechanism of gouging which occurs during hypervelocity sliding contact between two materials. A parameter study based on computer modeling of the gouging mechanism is presented in which gouging velocity thresholds are determined for several combinations of sliding materials. Materials which can gouge each other are found to do so only within a certain ... View full abstract»

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  • Direct measurement of rail resistance

    Publication Year: 1989, Page(s):88 - 91
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (292 KB)

    An experimental technique for directly measuring rail resistance during a railgun firing is described. A simple railgun flux loop is the only additional instrumentation (beyond standard instrumentation) required to determine rail resistance. Several tests were conducted to verify this rail resistance measurement technique. Typical test data for current, dI/dt, flux loop voltage, breech voltage and... View full abstract»

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  • An investigation into the potential for multiple rail railguns

    Publication Year: 1989, Page(s):92 - 96
    Cited by:  Papers (8)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (431 KB)

    A simple numerical technique for determining current distribution and inductance in parallel conductor geometries is outlined. Interim results of an ongoing study which applies this technique to analyze and compare two- and multirail railgun geometries are presented. Multirail candidates were compared to comparably sized two-rail counterparts. The railguns were compared on their ability to produce... View full abstract»

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  • Summary of experimental results using the REMGUN III HPG facility

    Publication Year: 1989, Page(s):97 - 101
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (436 KB)

    As part of the ongoing research program into electromagnetic (EM) guns at the Royal Armament Research and Development Establishment (RARDE), work has been carried out on several railgun barrel/switch systems which have been installed in an enclosed 100-yd range. Using the REMGUN III 6.7-MJ HPG (homopolar generator) pulsed power supply, explosive and mechanical commutating opening switches have bee... View full abstract»

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  • Operating principles of the ultracapacitor

    Publication Year: 1989, Page(s):102 - 106
    Cited by:  Papers (58)  |  Patents (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (419 KB)

    The charge-storage mechanism and the design of the ultracapacitor are described. Based on a ceramic with an extremely high specific surface area and a metallic substrate, the ultracapacitor provides extremely high energy densities and exhibits low ESR (equivalent series resistance). The combination of low ESR and extremely low inductance provides the ultracapacitor with a very high power density a... View full abstract»

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  • Explosive foil injection (EFI) pre-accelerator for electromagnetic launchers

    Publication Year: 1989, Page(s):107 - 110
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (302 KB)

    The use of an explosive foil injection system (EFI) for imparting an initial velocity on a projectile prior to its entering the breech of a railgun is demonstrated. This will substantially reduce the dwell time of the main arc at the breech end of the rails, which will greatly reduce the rail and dielectric ablation of the bore when compared to standing start systems. The preinjection system uses ... View full abstract»

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  • EMACK improvements, present and future

    Publication Year: 1989, Page(s):111 - 115
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (392 KB)

    A three-step program has been developed to improve the single-shot performance and to add 1-Hz repetitive operation capabilities to the EMACK electromagnetic launcher system. Single-shot performance is improved in two steps: first by copper-plating the HPG (homopolar generator) rotor, increasing the switch shuttle surface area, and developing a stronger barrel; and then by augmenting the inductive... View full abstract»

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  • Mass penalties in DC HPG design

    Publication Year: 1989, Page(s):116 - 120
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (290 KB)

    The authors developed theoretical mass and size models of iron-core HPGs (homopolar generators). They then analyzed the sensitivity of the size and mass of the HPG's to variations in HPG performance requirements, and key independent design parameters. The mass and size of the HPG was found to depend strongly on the output voltage and current requirements, the slip ring velocity, the current densit... View full abstract»

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  • Prototype development of a battery power supply at the electromagnetic launcher research facility

    Publication Year: 1989, Page(s):121 - 126
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (349 KB)

    Electromagnetic launcher (EML) research at Elgin Air Force Base has progressed beyond available power source levels. Therefore, an inexpensive, high-power, high-energy battery system is under construction to fulfil present and future requirements. Data on the subscale battery power supply (BPS) system are examined. Decisions made on the design and operation of pneumatic switches, batteries, and co... View full abstract»

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  • Thermal analysis of fiber armatures

    Publication Year: 1989, Page(s):127 - 132
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (519 KB)

    A detailed time-dependent thermal model using temperature-dependent material properties has been developed and implemented in the Westinghouse railgun simulation code to estimate interface temperature for fiber armatures. Fiber and rail materials are selected to protect the rails by confining deformation and melting to the armature. Heat generation at the interface, composed of electrical contact ... View full abstract»

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  • Electromagnetic gun/projectile interface considerations

    Publication Year: 1989, Page(s):133 - 137
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (570 KB)

    Projectile/electromagnetic-gun interface design considerations for electromagnetic gun weapon system (EMGWS) area D1 projectiles, area B-guns, and area C-guns are presented. Projectile/EM gun interfaces are primary considerations in the projectile structural design and the design of the sabot obturator/bore rider, pusher plate, and armature. Acceleration profile, armature type and mass, preinjecto... View full abstract»

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  • State-of-the-art insulator and electrode materials for use in high current high energy switching

    Publication Year: 1989, Page(s):138 - 141
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (303 KB)

    An investigation into the failure of ceramic insulators that are used in a surface discharge switch (SDS) was conducted. The materials analyzed are Al/sub 2/O/sub 3/-25% SiC, MTF (modified alumina titanate), and CZA 500 (zirconia-alumina composite) ceramics. These insulators were subjected to high-current ( approximately 300 kA) surface discharges in atmospheric air and nitrogen. Energy-dispersive... View full abstract»

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Aims & Scope

IEEE Transactions on Magnetics is a peer-reviewed, archival journal in science and technology related to the basic physics and engineering of magnetism, magnetic materials, applied magnetics, magnetic devices, and magnetic data storage. The journal publishes scholarly articles of archival value as well as tutorial expositions and critical reviews of classical subjects and topics of current interest.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Pavel Kabos
National Institute of Standards and Technology