Modular transportable superconducting magnetic energy systems

Science.gov (United States)

Lieurance, Dennis; Kimball, Foster; Rix, Craig

1995-04-01

Design and cost studies were performed for the magnet components of mid-size (1-5 MWh), cold supported SMES systems using alternative configurations. The configurations studied included solenoid magnets, which required onsite assembly of the magnet system, and toroid and racetrack configurations which consisted of factory assembled modules. For each configuration, design concepts and cost information were developed for the major features of the magnet system including the conductor, electrical insulation, and structure. These studies showed that for mid-size systems, the costs of solenoid and toroid magnet configurations are comparable and that the specific configuration to be used for a given application should be based upon customer requirements such as limiting stray fields or minimizing risks in development or construction.

Design and construction of a resistive energy dump device for bipolar superconducting magnet systems

Energy Technology Data Exchange (ETDEWEB)

Mohan, M. J.

1977-05-01

When superconducting magnets quench, the resistance of the conductor material rises rapidly to its normal value. This increase in resistance can result in catastrophic heating in the magnet unless stored field energy is quickly removed from the system. Phase inversion is the normal mode of energy removal. SCR's in the power supply are phased back, the output of the supply is inverted, and magnetic field energy is directed back into the utility grid. Under certain conditions, however, the power supply may fail to invert properly, and an alternate energy removal scheme must protect the superconducting magnet system. Composed of an isolation switch, a semiconductor switching module, and a dump resistor, the resistive dump device provides a viable protection scheme. Operationally, several conditions are capable of activating the isolation switch and triggering the bipolar SCR switching module. Manual dump commands, for instance, permit the operator to dump field energy in the event of observed abnormalities. A special voltage tap quench detector senses the aforementioned abnormal power supply output inversion and also fires the dump circuit. Regardless of the nature of the trigger input, however, activation of the energy dump device diverts coil current through the dump resistor. I/sup 2/R losses over time then safely dissipate stored magnetic field energy.

Superconducting magnets in high energy physics

International Nuclear Information System (INIS)

Prodell, A.G.

1978-01-01

The applications of superconducting magnets in high energy physics in the last ten years have made feasible developments which are vital to high energy research. These developments include high magnetic field, large volume detectors, such as bubble chambers, required for effective resolution of high energy particle trajectories, particle beam transport magnets, and superconducting focusing and bending magnets for the very high energy accelerators and storage rings needed to pursue the study of interactions between elementary particles. The acceptance of superconductivity as a proven technology in high energy physics was reinforced by the recognition that the existing large accelerators using copper-iron magnets had reached practical limits in terms of magnetic field intensity, cost, space, and energy usage, and that large-volume, high-field, copper-iron magnets were not economically feasible. Some of the superconducting magnets and associated systems being used in and being developed for high energy physics are described

Development of REBCO HTS Magnet of Magnetic Bearing for Large Capacity Flywheel Energy Storage System

Science.gov (United States)

Mukoyama, Shinichi; Matsuoka, Taro; Furukawa, Makoto; Nakao, Kengo; Nagashima, Ken; Ogata, Masafumi; Yamashita, Tomohisa; Hasegawa, Hitoshi; Yoshizawa, Kazuhiro; Arai, Yuuki; Miyazaki, Kazuki; Horiuchi, Shinichi; Maeda, Tadakazu; Shimizu, Hideki

A flywheel energy storage system (FESS) is a promising electrical storage system that moderates fluctuation of electrical power from renewable energy sources. The FESS can charge and discharge the surplus electrical power repetitively with the rotating energy. Particularly, the FESS that utilizes a high temperature superconducting magnetic bearing (HTS bearing) is lower loss than conventional FESS that has mechanical bearing, and has property of longer life operation than secondary batteries. The HTS bearing consists of a HTS bulk and double-pancake coils used 2nd generation REBCO wires. In the development, the HTS double-pancake coils were fabricated and were provided for a levitation test to verify the possibility of the HTS bearing. We successfully confirmed the magnetic field was achieved to design value, and levitation force in the configuration of one YBCO bulk and five double pan-cake coils was obtained to a satisfactory force of 39.2 kN (4 tons).

Numerical analysis of magnetic field in superconducting magnetic energy storage

International Nuclear Information System (INIS)

Kanamaru, Y.; Amemiya, Y.

1991-01-01

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

Rare-earth magnet applications in energy conversion

International Nuclear Information System (INIS)

Tripathi, K.C.

1998-01-01

In recent years there has been considerable progress in the field of development and variety of new applications of rare-earth and rare-earth transition metal magnets. High energy content Nd-Fe-B magnet system which competes with superconducting magnets is very promising for the use in energy conversion machines, levitation systems, magnetic resonance investigation and other magnetic applications. Energy conversion machines such as motors and generators are of interest in this context. Motor converts electrical energy into mechanical energy using permanent magnets and ferromagnetic materials as its components. Electric generator converts mechanical energy into electricity using permanent magnets and ferromagnetic material. In both cases symmetry and symmetry breaking play an important role. Symmetry exists above curie temperature, as temperature is lowered symmetry is broken due to spontaneous magnetisation. Author and coworkers developed some new and highest efficiency, permanent magnet based, electronically controlled, dynamically synchronised pulsed dc linear and rotational motors which are briefly described here. Based on such experience and considering field interactions inside material under dynamical conditions and special geometrical situations, order-disorder processes, symmetry breaking and energy transfer on the basis of manifold aspects as a cooperative many body interaction, thermal fluctuations, zero-point energy, dissipation of energy, entropy exchange are discussed in context of conversion of environmental heat into electricity as suggested by Tripathi earlier. (orig.)

Report on the production magnet measurement system for the Fermilab Energy-Saver superconducting dipoles and quadrupoles

International Nuclear Information System (INIS)

Brown, B.C.; Cooper, W.E.; Garvey, J.D.

1983-03-01

The measurement system and procedures used to test more than 900 superconducting dipole magnets and more than 275 superconducting quadrupole magnets for the Fermilab Energy Saver are described. The system is designed to measure nearly all parameters relevant to the use of the magnets in the accelerator including maximum field capability and precision field measurements. The performance of the instrumentation with regard to precision, reliability, and operational needs for high volume testing will be described. Previous reports have described the measurement system used during development of the Saver magnets from which this system has evolved

SMES [Superconducting Magnetic Energy Storage] systems applications to improve quality service

Energy Technology Data Exchange (ETDEWEB)

Esteban, P.; Gutierrez-Iglesias, J.L. [ASINEL (Spain); Bautista, A. [IBERDROLA (Spain); Rodriguez, J.M.; Urretavizcaya, E. [Red Electrica de Espana (Spain)

1997-12-31

This article presents the contribution of SMES (Superconducting Magnetic Energy Storage) systems to improvement quality of service, either as a mitigating element or as a power support for critical loads. It also describes these systems and its operation. Finally, a description is shown of the state of the art of this technology in Spain, as developed until now in the AMAS500 project. (Author)

1-GWh diurnal load-leveling superconducting magnetic energy storage system reference design. Appendix D: superconductive magnetic energy storage cavern construction methods and costs

International Nuclear Information System (INIS)

1979-09-01

The excavation and preparation of an underground cavern to contain a 1-GWh diurnal load-leveling Superconducting Magnetic Energy Storage (SMES) unit is examined. The cavern's principal function is to provide a rock structure for supporting the magnetic forces from the charged storage coil. Certain economic considerations indicate the refrigerator cold box for the helium system should also be underground. The study includes such a provision and considers, among other things, rock bolting, water seepage, concrete lining of the walls, steel bearing pads, a system to prevent freezing of the walls, a mining schedule, and costs

Flywheel Energy Storage System Suspended by Hybrid Magnetic Bearing

Science.gov (United States)

Owusu-Ansah, Prince; Hu, Yefa; Misbawu, Adam

This work presents a prototype flywheel energy storage system (FESS) suspended by hybrid magnetic bearing (HMB) rotating at a speed of 20000rpm with a maximum storage power capacity of 30W with a maximum tip speed of 300m/s. The design presented is an improvement of most existing FESS, as the design incorporates a unique feature in that the upper and the lower rotor and stator core are tapered which enhances larger thrust and much lower radial force to be exerted on the system. Without any adverse effect being experienced by the model. The work also focuses on the description of developing a prototype FESS suspended by HMB using solid works as a basis of developing in the nearer future a more improved FESS suspended by HMB capable of injecting the ever increasing high energy demand situation in the 21st century and beyond.

A Wireless Magnetic Resonance Energy Transfer System for Micro Implantable Medical Sensors

Directory of Open Access Journals (Sweden)

Tianyang Yang

2012-07-01

Full Text Available Based on the magnetic resonance coupling principle, in this paper a wireless energy transfer system is designed and implemented for the power supply of micro-implantable medical sensors. The entire system is composed of the in vitro part, including the energy transmitting circuit and resonant transmitter coils, and in vivo part, including the micro resonant receiver coils and signal shaping chip which includes the rectifier module and LDO voltage regulator module. Transmitter and receiver coils are wound by Litz wire, and the diameter of the receiver coils is just 1.9 cm. The energy transfer efficiency of the four-coil system is greatly improved compared to the conventional two-coil system. When the distance between the transmitter coils and the receiver coils is 1.5 cm, the transfer efficiency is 85% at the frequency of 742 kHz. The power transfer efficiency can be optimized by adding magnetic enhanced resonators. The receiving voltage signal is converted to a stable output voltage of 3.3 V and a current of 10 mA at the distance of 2 cm. In addition, the output current varies with changes in the distance. The whole implanted part is packaged with PDMS of excellent biocompatibility and the volume of it is about 1 cm³.

Energy considerations concerning current loops and magnetic objects

NARCIS (Netherlands)

Fluitman, J.H.J.

1980-01-01

In the thermodynamics of compound magnetic systems there is an ambiguity in defining the free energies connected to the constituent parts or subsystems. It is argued that the choice, usually made in defining the energy of a magnetized body, leads to an expression for the energy of a current loop or

Dynamic characteristics of a flywheel energy storage system using superconducting magnetic bearings

CERN Document Server

Kim, J S

2003-01-01

The high-temperature superconducting magnetic bearing flywheel energy storage system (SMB-FESS) is proposed as an efficient energy storage system. It is important to identify the dynamic behaviour and the characteristics of the SMB-FESS. First, a new method for identifying SMB characteristics has been suggested. The suggested modelling method is verified by comparing the experimental and analytical frequency response functions. In this study, the analyses of critical speed and unbalance response are performed using the analytical model. The experimental test has been carried out to verify the result of simulation. A good agreement has been observed between the experiment and the simulation result.

LHC magnet quench protection system

Science.gov (United States)

Coull, L.; Hagedorn, D.; Remondino, V.; Rodriguez-Mateos, F.

1994-07-01

The quench protection system for the superconducting magnets of the CERN Large Hadron Collider (LHC) is described. The system is based on the so called 'cold diode' concept. In a group of series connected magnets if one magnet quenches then the magnetic energy of all the magnets will be dissipated in the quenched magnet so destroying it. This is avoided by by-passing the quenched magnet and then rapidly de-exciting the unquenched magnets. For the LHC machine it is foreseen to use silicon diodes situated inside the cryostat as by-pass elements - so called 'cold diodes'. The diodes are exposed to some 50 kGray of radiation during a 10 year operation life-time. The high energy density of the LHC magnets (500 kJ/m) coupled with the relatively slow propagation speed of a 'natural' quench (10 to 20 m/s) can lead to excessive heating of the zone where the quench started and to high internal voltages. It is therefore necessary to detect quickly the incipient quench and fire strip heaters which spread the quench out more quickly over a large volume of the magnet. After a quench the magnet chain must be de-excited rapidly to avoid spreading the quench to other magnets and over-heating the by-pass diode. This is done by switching high-power energy-dump resistors in series with the magnets. The LHC main ring magnet will be divided into 16 electrically separated units which has important advantages.

LHC magnet quench protection system

International Nuclear Information System (INIS)

Coull, L.; Hagedorn, D.; Remondino, V.; Rodriguez-Mateos, F.

1994-01-01

The quench protection system for the superconducting magnets of the CERN Large Hadron Collider (LHC) is described. The system is based on the so called ''cold diode'' concept. In a group of series connected magnets if one magnet quenches then the magnetic energy of all the magnets will be dissipated in the quenched magnet so destroying it. This is avoided by by-passing the quenched magnet and then rapidly de-exciting the unquenched magnets. For the LHC machine it is foreseen to use silicon diodes situated inside the cryostat as by-pass elements--so called ''cold diodes''. The diodes are exposed to some 50 kGray of radiation during a 10 year operation life-time. The high energy density of the LHC magnets (500 kJ/m) coupled with the relatively slow propagation speed of a ''natural'' quench (10 to 20 m/s) can lead to excessive heating of the zone where the quench started and to high internal voltages. It is therefore necessary to detect quickly the incipient quench and fire strip heaters which spread the quench out more quickly over a large volume of the magnet. After a quench the magnet chain must be de-excited rapidly to avoid spreading the quench to other magnets and over-heating the by-pass diode. This is done by switching high-power energy-dump resistors in series with the magnets. The LHC main ring magnet will be divided into 16 electrically separated units which has important advantages

Reduction of Cogging Torque in Dual Rotor Permanent Magnet Generator for Direct Coupled Wind Energy Systems

Science.gov (United States)

Paulsamy, Sivachandran

2014-01-01

In wind energy systems employing permanent magnet generator, there is an imperative need to reduce the cogging torque for smooth and reliable cut in operation. In a permanent magnet generator, cogging torque is produced due to interaction of the rotor magnets with slots and teeth of the stator. This paper is a result of an ongoing research work that deals with various methods to reduce cogging torque in dual rotor radial flux permanent magnet generator (DRFPMG) for direct coupled stand alone wind energy systems (SAWES). Three methods were applied to reduce the cogging torque in DRFPMG. The methods were changing slot opening width, changing magnet pole arc width and shifting of slot openings. A combination of these three methods was applied to reduce the cogging torque to a level suitable for direct coupled SAWES. Both determination and reduction of cogging torque were carried out by finite element analysis (FEA) using MagNet Software. The cogging torque of DRFPMG has been reduced without major change in induced emf. A prototype of 1 kW, 120 rpm DRFPMG was fabricated and tested to validate the simulation results. The test results have good agreement with the simulation predictions. PMID:25202746

Reduction of cogging torque in dual rotor permanent magnet generator for direct coupled wind energy systems.

Science.gov (United States)

Paulsamy, Sivachandran

2014-01-01

In wind energy systems employing permanent magnet generator, there is an imperative need to reduce the cogging torque for smooth and reliable cut in operation. In a permanent magnet generator, cogging torque is produced due to interaction of the rotor magnets with slots and teeth of the stator. This paper is a result of an ongoing research work that deals with various methods to reduce cogging torque in dual rotor radial flux permanent magnet generator (DRFPMG) for direct coupled stand alone wind energy systems (SAWES). Three methods were applied to reduce the cogging torque in DRFPMG. The methods were changing slot opening width, changing magnet pole arc width and shifting of slot openings. A combination of these three methods was applied to reduce the cogging torque to a level suitable for direct coupled SAWES. Both determination and reduction of cogging torque were carried out by finite element analysis (FEA) using MagNet Software. The cogging torque of DRFPMG has been reduced without major change in induced emf. A prototype of 1 kW, 120 rpm DRFPMG was fabricated and tested to validate the simulation results. The test results have good agreement with the simulation predictions.

Magnetic-fusion energy and computers

International Nuclear Information System (INIS)

Killeen, J.

1982-01-01

The application of computers to magnetic fusion energy research is essential. In the last several years the use of computers in the numerical modeling of fusion systems has increased substantially. There are several categories of computer models used to study the physics of magnetically confined plasmas. A comparable number of types of models for engineering studies are also in use. To meet the needs of the fusion program, the National Magnetic Fusion Energy Computer Center has been established at the Lawrence Livermore National Laboratory. A large central computing facility is linked to smaller computer centers at each of the major MFE laboratories by a communication network. In addition to providing cost effective computing services, the NMFECC environment stimulates collaboration and the sharing of computer codes among the various fusion research groups

Magnetic fusion energy and computers

International Nuclear Information System (INIS)

Killeen, J.

1982-01-01

The application of computers to magnetic fusion energy research is essential. In the last several years the use of computers in the numerical modeling of fusion systems has increased substantially. There are several categories of computer models used to study the physics of magnetically confined plasmas. A comparable number of types of models for engineering studies are also in use. To meet the needs of the fusion program, the National Magnetic Fusion Energy Computer Center has been established at the Lawrence Livermore National Laboratory. A large central computing facility is linked to smaller computer centers at each of the major MFE laboratories by a communication network. In addition to providing cost effective computing services, the NMFECC environment stimulates collaboration and the sharing of computer codes among the various fusion research groups

Dissipation of magnetic energy during disruptive current termination

International Nuclear Information System (INIS)

Yamazaki, K.; Schmidt, G.L.

1983-09-01

The magnetic coupling during a disruption between the plasma and the various coil systems on the PDX tokamak has been modeled. Using measured coil currents, the model indicates that dissipation of magnetic energy in the plasma equal to 75 % of the energy stored in the poloidal field of the plasma current does occur and that coupling between the plasma and the coil systems can reduce such dissipation. In the case of PDX ohmic discharges, bolometric measurements of radiation and charge exchange, integrated over a disruption, account for 90 % of the calculated energy dissipation. (author)

Magnetic flux concentration methods for magnetic energy harvesting module

Directory of Open Access Journals (Sweden)

Wakiwaka Hiroyuki

2013-01-01

Full Text Available This paper presents magnetic flux concentration methods for magnetic energy harvesting module. The purpose of this study is to harvest 1 mW energy with a Brooks coil 2 cm in diameter from environmental magnetic field at 60 Hz. Because the harvesting power is proportional to the square of the magnetic flux density, we consider the use of a magnetic flux concentration coil and a magnetic core. The magnetic flux concentration coil consists of an air­core Brooks coil and a resonant capacitor. When a uniform magnetic field crossed the coil, the magnetic flux distribution around the coil was changed. It is found that the magnetic field in an area is concentrated larger than 20 times compared with the uniform magnetic field. Compared with the air­core coil, our designed magnetic core makes the harvested energy ten­fold. According to ICNIRP2010 guideline, the acceptable level of magnetic field is 0.2 mT in the frequency range between 25 Hz and 400 Hz. Without the two magnetic flux concentration methods, the corresponding energy is limited to 1 µW. In contrast, our experimental results successfully demonstrate energy harvesting of 1 mW from a magnetic field of 0.03 mT at 60 Hz.

Structure requirements for magnetic energy storage devices

International Nuclear Information System (INIS)

Eyssa, Y.M.; Huang, X.

1993-01-01

Large variety of large and small magnetic energy storage systems have been designed and analyzed in the last 20 years. Cryoresistive and superconductive energy storage (SMES) magnets have been considered for applications such as load leveling for electric utilities, pulsed storage for electromagnetic launchers and accelerator devices, and space borne superconductive energy storage systems. Large SMES are supported by a combination of cold and warm structure while small SMES are supported only by cold structure. In this article we provide analytical and numerical tools to estimate the structure requirements as function of the stored energy and configuration. Large and small solenoidal and toroidal geometries are used. Considerations for both warm and cold structure are discussed. Latest design concepts for both large and small units are included. (orig.)

Direct conversion of fusion energy into the electric one in the 'Dragon' magnetic confinement system

International Nuclear Information System (INIS)

Glagolev, V.M.; Timofeev, A.V.

1993-01-01

It is shown that recuperator in which the thermal energy of particles is transformed into electric oue under drift in crossed fields is naturally coupled with dragontype magnetic confinement system, so the recuperation process can be initiated in the dragon magnetic field. A number of questions occuring under analysis of recuperator-dragon system is considered, including the dynamics of particle transfer to the recuperator, the share of particles entering the recuperator, the effect of rotational transform and the recuperation efficiency

Electrical protection of superconducting magnet systems

International Nuclear Information System (INIS)

Sutter, D.F.; Flora, R.H.

1975-01-01

The problem of dissipating the energy stored in the field of a superconducting magnet when a quench occurs has received considerable study. However, when the magnet becomes a system 4 miles in length whose normal operation is an ac mode, some re-examination of standard techniques for dissipating energy outside the magnets is in order. Data accumulated in the Fermilab Energy Doubler magnet development program shows that heating associated with the temporal and spatial development of quenches is highly localized and can result in temperatures damaging to the superconducting wire. The design and operation are discussed for several energy dumping schemes, compatible with the operation of ac superconducting magnets, wherein more than 70 percent of the stored energy can be dissipated outside the magnet. Instrumentation to detect quenches early in their development and circuits for dumping the field energy are described, and representative operating performance data for the dump circuits and data showing temporal development of quenches are presented. (auth)

Development of energy-harvesting system using deformation of magnetic elastomer

Science.gov (United States)

Shinoda, Hayato; Tsumori, Fujio

2018-06-01

In this paper, we propose a power generation method using the deformation of a magnetic elastomer for vibration energy harvesting. The magnetic flux lines in the structure of the magnetic elastomer could be markedly changed if the properly designed structure was expanded and contracted in a static magnetic field. We set a coil on the magnetic elastomer to generate electricity by capturing this change in magnetic flux flow. We fabricated a centimeter-scale device and demonstrated that it generated 10.5 mV of maximum voltage by 10 Hz vibration. We also simulated the change in the magnetic flux flow using finite element analysis, and compared the result with the experimental data. Furthermore, we evaluated the power generation of a miniaturized device.

Magnetic fluctuations in heavy fermion systems

International Nuclear Information System (INIS)

Broholm, C.L.

1989-06-01

Magnetic order and fluctuations in the heavy Fermion systems UPt 3 , U 2 Zn 17 and URu 2 Si 2 have been studied by neutron scattering. Single crystalline samples and triple-axis neutron-scattering techniques with energy transfers between 0 and 40 meV and energy resolutions between 0.1 meV and 4 meV have been employed. UPt 3 develops an antiferromagnetically ordered moment of (0.02±0.005) μ B below T N = 5 K which doubles the unit cell in the basal plane and coexists with superconductivity below T c = 0.5 K. The magnetic fluctuations are relaxational, and enhanced at the antiferromagnetic zone center in a low-energy regime. The characteristic zone-center relaxation energy is 0.3 meV. The temperature- and field-dependence of the antiferromagnetic order in the superconducting phase suggest a close relation between these two properties in UPt 3 . U 2 Zn 17 has a broad spectrum of magnetic fluctuations, even below T N = 9.7 K, of which the transverse part below 10 meV is strongly enhanced at the antiferromagnetic zone center. The system has an anomalously extended critical region and the antiferromagnetic phase transition seems to be driven by the temperature-dependence of an effective RKKY interaction, as anticipated theoretically. URu 2 Si 2 , a strongly anisotropic heavy Fermion system, has a high-energy regime of antiferromagnetically-correlated overdamped magnetic fluctuations. Below T N = 17.5 K weak antiferromagnetic order, μ = (0.04±0.01)μ B , with finite correlations along the tetragonal c axis, develops along with a low-energy regime of strongly dispersive singlet-singlet excitations. Below T c = 1 K antiferromagnetism coexists with superconductivity. A phenomenological model describing the exchange-enhanced overdamped magnetic fluctuations of heavy Fermion systems is proposed. Our experimental results are compared to the anomalous bulk properties of heavy Fermion systems, and to magnetic fluctuations in other metallic magnets. (orig.)

Energy transfers and magnetic energy growth in small-scale dynamo

KAUST Repository

Kumar, Rohit Raj

2013-12-01

In this letter we investigate the dynamics of magnetic energy growth in small-scale dynamo by studying energy transfers, mainly energy fluxes and shell-to-shell energy transfers. We perform dynamo simulations for the magnetic Prandtl number Pm = 20 on 10243 grid using the pseudospectral method. We demonstrate that the magnetic energy growth is caused by nonlocal energy transfers from the large-scale or forcing-scale velocity field to small-scale magnetic field. The peak of these energy transfers moves towards lower wave numbers as dynamo evolves, which is the reason why the integral scale of the magnetic field increases with time. The energy transfers U2U (velocity to velocity) and B2B (magnetic to magnetic) are forward and local. Copyright © EPLA, 2013.

Application of superconducting magnet energy storage to improve power system dynamic performance

International Nuclear Information System (INIS)

Mitani, Y.; Tsuji, K.; Murakami, Y.

1988-01-01

The application of Superconducting Magnet Energy Storage (SMES) to the stabilization of a power system with long distance bulk power transmission lines which has the problem of poorly damped power oscillations, is presented. Control schemes for stabilization using SMES which is capable of controlling active and reactive power simultaneously in four quadrant ranges, is proposed. The effective locations and the necessary capacities of SMES for power system stabilizing control are discussed in detail. Results of numerical analysis and experiments in an artificial power transmission system demonstrate the significant effect of the control by SMES on the improvement of power system oscillatory performance

Superconducting magnetic energy storage

International Nuclear Information System (INIS)

Rogers, J.D.

1976-01-01

Fusion power production requires energy storage and transfer on short time scales to create confining magnetic fields and for heating plasmas. The theta-pinch Scyllac Fusion Test Reactor (SFTR) requires 480 MJ of energy to drive the 5-T compression field with a 0.7-ms rise time. Tokamak Experimental Power Reactors (EPR) require 1 to 2 GJ of energy with a 1 to 2-s rise time for plasma ohmic heating. The design, development, and testing of four 300-kJ energy storage coils to satisfy the SFTR needs are described. Potential rotating machinery and homopolar energy systems for both the Reference Theta-Pinch Reactor (RTPR) and tokamak ohmic-heating are presented

1-GWh diurnal load-leveling superconducting magnetic energy storage system reference design. Appendix A: energy storage coil and superconductor

International Nuclear Information System (INIS)

Schermer, R.I.

1979-09-01

The technical aspects of a 1-GWh Superconducting Magnetic Energy Storage (SMES) coil for use as a diurnal load-leveling device in an electric utility system are presented. The superconductor for the coil is analyzed, and costs for the entire coil are developed

High magnetic field MRI system

International Nuclear Information System (INIS)

Maeda, Hideaki; Urata, Masami; Satoh, Kozo

1990-01-01

A high field superconducting magnet, 4-5 T in central magnetic field, is required for magnetic resonance spectroscopic imaging (MRSI) on 31 P, essential nuclei for energy metabolism of human body. This paper reviews superconducting magnets for high field MRSI systems. Examples of the cross-sectional image and the spectrum of living animals are shown in the paper. (author)

Pulsed energy conversion with a dc superconducting magnet

International Nuclear Information System (INIS)

Cowan, M.; Cnare, E.C.; Leisher, W.B.; Tucker, W.K.; Wessenberg, D.L.

1976-01-01

A generator system for pulsed power is described which employs a dc superconducting magnet in a magnetic flux compression scheme. Experience with a small-scale generator together with projections of numerical models indicate potential applications to fusion research and commercial power generation. When the system is large enough pulse energy can exceed that stored in the magnet and pulse rise time can range from several microseconds to tens of milliseconds. (author)

Energy system for the generation of divertor magnetic fields in the PDX fusion research device

International Nuclear Information System (INIS)

Turitzin, N.M.

1975-01-01

One of the major problems encountered in the development of Tokamak type fusion reactors is the presence of impurities in the plasma. The PDX device is designed to study the operation of poloidal magnetic field divertors and consequent magnetic limiters for controlling and reducing the amount of impurities. A system of coils placed at specific locations produces a required field configuration for the poloidal divertor. This paper describes the system of energy supplies required and the interrelations of field coil currents during plasma current initiation, growth and steady state

Energy system for the generation of divertor magnetic fields in the PDX fusion research device

International Nuclear Information System (INIS)

Turitzin, N.M.

1976-05-01

One of the major problems encountered in the development of Tokamak type fusion reactors is the presence of impurities in the plasma. The PDX device is designed to study the operation of poloidal magnetic field divertors and consequent magnetic limiters for controlling and reducing the amount of impurities. A system of coils placed at specific locations produces a required field configuration for the poloidal divertor. This paper describes the system of energy supplies required and the interrelations of field coil currents during plasma current initiation, growth and steady state

Force Analysis and Energy Operation of Chaotic System of Permanent-Magnet Synchronous Motor

Science.gov (United States)

Qi, Guoyuan; Hu, Jianbing

2017-12-01

The disadvantage of a nondimensionalized model of a permanent-magnet synchronous Motor (PMSM) is identified. The original PMSM model is transformed into a Kolmogorov system to aid dynamic force analysis. The vector field of the PMSM is analogous to the force field including four types of torque — inertial, internal, dissipative, and generalized external. Using the feedback thought, the error torque between external torque and dissipative torque is identified. The pitchfork bifurcation of the PMSM is performed. Four forms of energy are identified for the system — kinetic, potential, dissipative, and supplied. The physical interpretations of the decomposition of force and energy exchange are given. Casimir energy is stored energy, and its rate of change is the error power between the dissipative energy and the energy supplied to the motor. Error torque and error power influence the different types of dynamic modes. The Hamiltonian energy and Casimir energy are compared to find the function of each in producing the dynamic modes. A supremum bound for the chaotic attractor is proposed using the error power and Lagrange multiplier.

Superconducting magnetic energy storage apparatus structural support system

Science.gov (United States)

Withers, Gregory J.; Meier, Stephen W.; Walter, Robert J.; Child, Michael D.; DeGraaf, Douglas W.

1992-01-01

A superconducting magnetic energy storage apparatus comprising a cylindrical superconducting coil; a cylindrical coil containment vessel enclosing the coil and adapted to hold a liquid, such as liquefied helium; and a cylindrical vacuum vessel enclosing the coil containment vessel and located in a restraining structure having inner and outer circumferential walls and a floor; the apparatus being provided with horizontal compression members between (1) the coil and the coil containment vessel and (2) between the coil containment vessel and the vacuum vessel, compression bearing members between the vacuum vessel and the restraining structure inner and outer walls, vertical support members (1) between the coil bottom and the coil containment vessel bottom and (2) between the coil containment vessel bottom and the vacuum vessel bottom, and external supports between the vacuum vessel bottom and the restraining structure floor, whereby the loads developed by thermal and magnetic energy changes in the apparatus can be accommodated and the structural integrity of the apparatus be maintained.

Stored energy in fusion magnet materials irradiated at low temperatures

International Nuclear Information System (INIS)

Chaplin, R.L.; Kerchner, H.R.; Klabunde, C.E.; Coltman, R.R.

1989-08-01

During the power cycle of a fusion reactor, the radiation reaching the superconducting magnet system will produce an accumulation of immobile defects in the magnet materials. During a subsequent warm-up cycle of the magnet system, the defects will become mobile and interact to produce new defect configurations as well as some mutual defect annihilations which generate heat-the release of stored energy. This report presents a brief qualitative discussion of the mechanisms for the production and release of stored energy in irradiated materials, a theoretical analysis of the thermal response of irradiated materials, theoretical analysis of the thermal response of irradiated materials during warm-up, and a discussion of the possible impact of stored energy release on fusion magnet operation 20 refs

Energy of magnetic moment of superconducting current in magnetic field

International Nuclear Information System (INIS)

Gurtovoi, V.L.; Nikulov, A.V.

2015-01-01

Highlights: • Quantization effects observed in superconducting loops are considered. • The energy of magnetic moment in magnetic field can not be deduced from Hamiltonian. • This energy is deduced from a history of the current state in the classical case. • It can not be deduced directly in the quantum case. • Taking this energy into account demolishes agreement between theory and experiment. - Abstract: The energy of magnetic moment of the persistent current circulating in superconducting loop in an externally produced magnetic field is not taken into account in the theory of quantization effects because of identification of the Hamiltonian with the energy. This identification misleads if, in accordance with the conservation law, the energy of a state is the energy expended for its creation. The energy of magnetic moment is deduced from a creation history of the current state in magnetic field both in the classical and quantum case. But taking this energy into account demolishes the agreement between theory and experiment. Impartial consideration of this problem discovers the contradiction both in theory and experiment

Highly efficient power system based on direct fission fragment energy conversion utilizing magnetic collimation

International Nuclear Information System (INIS)

Tsvetkov, Pavel V.; Hart, Ron R.; Parish, Theodore A.

2003-01-01

The present study was focused on developing a technologically feasible power system that is based on direct fission fragment energy conversion utilizing magnetic collimation. The new concept is an attempt to combine several advantageous design solutions, which have been proposed for application in both fission and fusion reactors, into one innovative system that can offer exceptional energy conversion efficiency. The analysis takes into consideration a wide range of operational aspects including fission fragment escape from the fuel, collimation, collection, criticality, long-term performance, energy conversion efficiency, heat removal, and safety characteristics. Specific characteristics of the individual system components and the entire system are evaluated. Consistent analysis and evaluation of the technological feasibility of the concept were achieved using state-of-the-art computer codes that allowed realistic and consistent modeling. The calculated energy conversion efficiencies for the presented designs without a thermodynamic cycle and with the heavy water cycle are 52% and 62%, respectively. The analysis indicates that efficiencies up to 90% are potentially achievable. (author)

Design of a magnetic braking system

International Nuclear Information System (INIS)

Jou, M.; Shiau, J.-K.; Sun, C.-C.

2006-01-01

A non-contact method, using magnetic drag force principle, was proposed to design the braking systems to improve the shortcomings of the conventional braking systems. The extensive literature detailing all aspects of the magnetic braking is briefly reviewed, however little of this refers specifically to upright magnetic braking system, which is useful for industries. One of the major issues to design upright magnetic system is to find out the magnetic flux. The changing magnetic flux induces eddy currents in the conductor. These currents dissipate energy in the conductor and generate drag force to slow down the motion. Therefore, a finite element model is developed to analyze the phenomena of magnetic flux density when air gap and materials of track are varied. The verification shows the predicted magnetic flux is within acceptable range with the measured value. The results will facilitate the design of magnetic braking systems

Passive magnetic bearing system

Science.gov (United States)

Post, Richard F.

2014-09-02

An axial stabilizer for the rotor of a magnetic bearing provides external control of stiffness through switching in external inductances. External control also allows the stabilizer to become a part of a passive/active magnetic bearing system that requires no external source of power and no position sensor. Stabilizers for displacements transverse to the axis of rotation are provided that require only a single cylindrical Halbach array in its operation, and thus are especially suited for use in high rotation speed applications, such as flywheel energy storage systems. The elimination of the need of an inner cylindrical array solves the difficult mechanical problem of supplying support against centrifugal forces for the magnets of that array. Compensation is provided for the temperature variation of the strength of the magnetic fields of the permanent magnets in the levitating magnet arrays.

Permanent Magnet Synchronous Generator Driven Wind Energy Conversion System Based on Parallel Active Power Filter

Directory of Open Access Journals (Sweden)

FERDI Brahim

2014-05-01

Full Text Available This paper proposes a novel application of the instantaneous P-Q theory in a wind energy conversion system (WECS. The proposed WECS is formed by permanent magnet synchronous generator (PMSG wind turbine system connected to the grid through parallel active power filter (PAPF. PAPF uses the generated wind energy to feed loads connected at the point of common coupling (PPC, compensates current harmonics and injects the excess of this energy into the grid using P-Q theory as control method. To demonstrate the feasibility and the performance of the proposed control scheme, simulation of this wind system has been realized using MATLAB/SIMULINK software. Simulation results show the accuracy and validity of the proposed control scheme for the PMSGPAPF system.

Design and optimization of superconducting magnet system for energy storage application

International Nuclear Information System (INIS)

Bhunia, Uttam

2015-01-01

In view of developing superconducting magnetic energy storage system (SMES) technology that will mitigate voltage sag/dip in the utility line, VEC centre has taken up a leading role in the country. In the first phase a solenoid-type 0.6 MJ SMES system using cryo-stable NbTi superconductor has been designed, developed and tested successfully with resistive load to mitigate power line voltage dips. The cryogenic test results of 0.6 MJ SMES coil will be highlighted. Further, effort is underway to develop a 4.5 MJ/1 MW SMES system with toroidal coil configuration. The lecture will also cover the superconducting coil development for SMES application with special emphasis on design aspects and the optimization issue of the toroidal system using NbTi based Rutherford-type cable. (author)

A current controlled matrix converter for wind energy conversion systems based on permanent magnet synchronous generator

OpenAIRE

Naggar H. Saad; Ahmed A. El-Sattar; Mohamed I. Marei

2016-01-01

The main challenges of wind energy conversion systems (WECS) are to maximize the energy capture from the wind and injecting reactive power during the fault. This paper presents a current controlled matrix converter to interface Permanent Magnet Synchronous Generators (PMSG) based WECS with the grid. To achieve fast dynamic response with reduced current ripples, a hysteresis current control is utilized. The proposed control system decouples the active and reactive components of the PMSG curren...

Energy transfer from a superconducting magnet to an inductive load

International Nuclear Information System (INIS)

Onishi, Toshitada; Miura, Akinori.

1977-01-01

Experiments on energy transfer between two superconducting magnets have been carried out using an inductive energy transfer system similar to the flying capacitor system developed at the Karlsruhe Institute. In the present system the capacitor is grounded and diodes are used instead of thyristors, and a fraction of stored energy is transferred to the capacitor only when the relay connected in parallel to the magnet is switched off. The capacitor is expected to have no constraint in size, while in the flying capacitor system the capacitor is required to exceed a threshold size. Consequently it is possible to shorten the transfer time to some extent in comparison with the one in the flying capacitor system. Transfer experiments have been carried out using a storage magnet with inductance of 1.2H and a load of 0.41H. The capacitance is 200μF. It is possible to transfer 80.1% of the stored energy of 221 J into the load in less than about 0.35 seconds. (auth.)

1-GWh diurnal load-leveling Superconducting Magnetic Energy Storage System reference design. Appendix G. Design study. Thyristor converter stations for use with superconducting magnetic energy storage systems

International Nuclear Information System (INIS)

Lindh, C.B.; Pohl, R.V.; Trojan, H.T.

1979-09-01

The cost for the power conversion equipment for four different SMES systems were developed. These were 1- and 5-GWh units for 4- and 8-h charge periods. Only constant power operation of the converter was considered with 10% of the maximum energy remaining in the magnet at the end of the discharge cycle. The cost increases almost linearly with the maximum coil current between 30 kA and 150 kA, and the cost for a 4-h charge system is about 20% lower than for an 8-h charge system. The converter terminal cost is estimated to be $40/kW of installed power for a 1-GWh 4-h charge system at 30 kA maximum current and $60/kW of installed power for a 5-GWh 4-h charge system at 50 kA maximum current

Robust Sliding Mode Control of Permanent Magnet Synchronous Generator-Based Wind Energy Conversion Systems

Directory of Open Access Journals (Sweden)

Guangping Zhuo

2016-12-01

Full Text Available The subject of this paper pertains to sliding mode control and its application in nonlinear electrical power systems as seen in wind energy conversion systems. Due to the robustness in dealing with unmodeled system dynamics, sliding mode control has been widely used in electrical power system applications. This paper presents first and high order sliding mode control schemes for permanent magnet synchronous generator-based wind energy conversion systems. The application of these methods for control using dynamic models of the d-axis and q-axis currents, as well as those of the high speed shaft rotational speed show a high level of efficiency in power extraction from a varying wind resource. Computer simulation results have shown the efficacy of the proposed sliding mode control approaches.

Magnetic energy storage and conversion in the solar atmosphere

Science.gov (United States)

Spicer, D. S.; Mariska, J. T.; Boris, J. P.

1986-01-01

According to the approach employed in this investigation, particularly important simple configurations of magnetic field and plasma are identified, and it is attempted to achieve an understanding of the large-scale dynamic processes and transformations which these systems can undergo. Fundamental concepts are discussed, taking into account aspects of magnetic energy generation, ideal MHD theory, non-MHD properties, the concept of 'anomalous' resistivity, and global electrodynamic coupling. Questions of magnetically controlled energy conversion are examined, giving attention to magnetic modifications of plasma transport, the transition region structure and flows, channeling and acceleration of plasma, channeling and dissipation of MHD waves, and anomalous dissipation of field-aligned currents. A description of the characteristics of magnetohydrodynamic energy conversion is also provided, and outstanding questions are discussed.

Directed Magnetic Particle Transport above Artificial Magnetic Domains Due to Dynamic Magnetic Potential Energy Landscape Transformation.

Science.gov (United States)

Holzinger, Dennis; Koch, Iris; Burgard, Stefan; Ehresmann, Arno

2015-07-28

An approach for a remotely controllable transport of magnetic micro- and/or nanoparticles above a topographically flat exchange-bias (EB) thin film system, magnetically patterned into parallel stripe domains, is presented where the particle manipulation is achieved by sub-mT external magnetic field pulses. Superparamagnetic core-shell particles are moved stepwise by the dynamic transformation of the particles' magnetic potential energy landscape due to the external magnetic field pulses without affecting the magnetic state of the thin film system. The magnetic particle velocity is adjustable in the range of 1-100 μm/s by the design of the substrate's magnetic field landscape (MFL), the particle-substrate distance, and the magnitude of the applied external magnetic field pulses. The agglomeration of magnetic particles is avoided by the intrinsic magnetostatic repulsion of particles due to the parallel alignment of the particles' magnetic moments perpendicular to the transport direction and parallel to the surface normal of the substrate during the particle motion. The transport mechanism is modeled by a quantitative theory based on the precise knowledge of the sample's MFL and the particle-substrate distance.

Broadband piezoelectric energy harvesting using nonlinear magnetic forces; Bandbreitensteigerung von piezoelektrischen Energy Harvesting Systemen durch Magnetkraefte

Energy Technology Data Exchange (ETDEWEB)

Westermann, Henrik; Neubauer, Marcus; Wallaschek, Joerg [Hannover Univ. (Germany). Inst. fuer Dynamik und Schwingungen

2012-07-15

Using ambient energy by piezoelectric energy harvesting systems received much attention over the last years. Most vibration-based generators produce a sufficient power only if the transducer is excited in its resonance frequency. The use of magnetic forces suggests a promising strategy to increase the efficiency. This paper presents different ways for broadband piezoelectric energy harvesting using nonlinear magnetic forces. (orig.)

On test results of the superconducting magnetic energy storage (SMES) system in Ariuragawa Power Station

International Nuclear Information System (INIS)

Katahira, Osamu; Fukui, Fumihiko; Karano, Koichi; Irie, Fujio; Takeo, Masakatsu; Okada, Hidehiko; Shimojo, Toshikazu.

1991-01-01

SMES system is that for storing electric energy in the form of magnetic energy by flowing DC current through a superconducting coil by utilizing the characteristics of its superconductivity. It comprises a superconducting coil for storing energy, an AC-DC converter, the cooling system for maintaining extremely low temperature and so on. The features of SMES are the high efficiency of storing electric energy (more than 90 % in the large scale system), the fast response to store and release electric power, and effective power and reactive power can be independently and arbitrarily controlled. It is expected that SMES can be applied to the stabilization of electric power system, the adjustment of system voltage, the adjustment of varying load and so on. In order to verify the results of the laboratory research in actual power system, the system test was carried out in Ariuragawa Power Station on November 20-22, 1990. The outline of the test, the method of controlling SMES, the test results and the examination of the results are reported. (K.I.)

Prototype test of Energy Doubler/Saver bending magnet

International Nuclear Information System (INIS)

Yamada, R.; Ishimoto, H.; Price, M.E.

1977-01-01

An improved full scale bending magnet for the Energy Doubler was cooled down with a prototype satellite refrigerator and its characteristics were measured. Quenches were intentionally induced on this magnet below 40 kG using a heater, and the quench behavior was investigated from the viewpoint of system safety. The first self-induced quench of this horizontal magnet system occurred at about 41.7 kG. Due to high single phase pressure, the magnet was not trained to any higher field. The measurement of ac loss was done, and the data showed some wire movement at about 20 kG. Transfer function was measured to be 9.81 (G/A). The magnetic field was measured using a harmonic coil. The field quality was found to be improved over the first full scale magnet

Mirror Fusion Test Facility magnet system

International Nuclear Information System (INIS)

VanSant, J.H.; Kozman, T.A.; Bulmer, R.H.; Ng, D.S.

1981-01-01

In 1979, R.H. Bulmer of Lawrence Livermore National Laboratory (LLNL) discussed a proposed tandem-mirror magnet system for the Mirror Fusion Test Facility (MFTF) at the 8th symposium on Engineering Problems in Fusion Research. Since then, Congress has voted funds for expanding LLNL's MFTF to a tandem-mirror facility (designated MFTF-B). The new facility, scheduled for completion by 1985, will seek to achieve two goals: (1) Energy break-even capability (Q or the ratio of fusion energy to plasma heating energy = 1) of mirror fusion, (2) Engineering feasibility of reactor-scale machines. Briefly stated, 22 superconducting magnets contained in a 11-m-diam by 65-m-long vacuum vessel will confine a fusion plasma fueled by 80 axial streaming-plasma guns and over 40 radial neutral beams. We have already completed a preliminary design of this magnet system

Magnetic energy storage

International Nuclear Information System (INIS)

Rogers, J.D.

1980-01-01

The fusion program embraces low loss superconductor strand development with integration into cables capable of carrying 50 kA in pulsed mode at high fields. This evolvement has been paralleled with pulsed energy storage coil development and testing from tens of kJ at low fields to a 20 MJ prototype tokamak induction coil at 7.5 T. Energy transfer times have ranged from 0.7 ms to several seconds. Electric utility magnetic storage for prospective application is for diurnal load leveling with massive systems to store 10 GWh at 1.8 K in a dewar structure supported on bedrock underground. An immediate utility application is a 30 MJ system to be used to damp power oscillations on the Bonneville Power Administration electric transmission lines. An off-shoot of this last work is a new program for electric utility VAR control with the potential for use to suppress subsynchronous resonance. This paper presents work in progress, work planned, and recently completed unusual work

Magnetic field effects on exciplex-forming systems: the effect on the locally excited fluorophore and its dependence on free energy.

Science.gov (United States)

Kattnig, Daniel R; Rosspeintner, Arnulf; Grampp, Günter

2011-02-28

This study addresses magnetic field effects in exciplex forming donor-acceptor systems. For moderately exergonic systems, the exciplex and the locally excited fluorophore emission are found to be magneto-sensitive. A previously introduced model attributing this finding to excited state reversibility is confirmed. Systems characterised by a free energy of charge separation up to approximately -0.35 eV are found to exhibit a magnetic field effect on the fluorophore. A simple three-state model of the exciplex is introduced, which uses the reaction distance and the asymmetric electron transfer reaction coordinate as pertinent variables. Comparing the experimental emission band shapes with those predicted by the model, a semi-quantitative picture of the formation of the magnetic field effect is developed based on energy hypersurfaces. The model can also be applied to estimate the indirect contribution of the exchange interaction, even if the perturbative approach fails. The energetic parameters that are essential for the formation of large magnetic field effects on the exciplex are discussed.

Performance of the LHC magnet system

CERN Document Server

Parma, V

2010-01-01

The LHC magnet system, essentially composed of superconducting magnets operating at 1.9 K, has been largely commissioned in 2007-08. Before the serious incident of 19th September 2008, the magnet system was commissioned up to 7 kA (4 TeV proton beam energy); six (out of eight) sectors were commissioned up to 5.5 TeV and one up to 6.6 TeV. For more than one week, both beams have been injected, circulated and captured in the RF bucket, thus assessing the optics at injection energy. The incident in sector 3-4, originated by a serious defect of a high-current joint between magnets with large collateral damage, has changed the plans: 53 magnets in the damaged zone have been substituted or repaired meanwhile a campaign of consolidation is under way to allow safe restart of the accelerator in fall 2009. All these points and other issues presented and discussed, with emphasis on the incident in sector 3-4.

ATLAS Magnet System Nearing Completion

CERN Document Server

ten Kate, H H J

2008-01-01

The ATLAS Detector at the Large Hadron Collider at CERN is equipped with a superconducting magnet system that consists of a Barrel Toroid, two End-Cap Toroids and a Central Solenoid. The four magnets generate the magnetic field for the muon- and inner tracking detectors, respectively. After 10 years of construction in industry, integration and on-surface tests at CERN, the magnets are now in the underground cavern where they undergo the ultimate test before data taking in the detector can start during the course of next year. The system with outer dimensions of 25 m length and 22 m diameter is based on using conduction cooled aluminum stabilized NbTi conductors operating at 4.6 K and 20.5 kA maximum coil current with peak magnetic fields in the windings of 4.1 T and a system stored magnetic energy of 1.6 GJ. The Barrel Toroid and Central Solenoid were already successfully charged after installation to full current in autumn 2006. This year the system is completed with two End Cap Toroids. The ultimate test of...

Energy transfers and magnetic energy growth in small-scale dynamo

KAUST Repository

Kumar, Rohit Raj; Verma, Mahendra K.; Samtaney, Ravi

2013-01-01

In this letter we investigate the dynamics of magnetic energy growth in small-scale dynamo by studying energy transfers, mainly energy fluxes and shell-to-shell energy transfers. We perform dynamo simulations for the magnetic Prandtl number Pm = 20

Robustness Improvement of Superconducting Magnetic Energy Storage System in Microgrids Using an Energy Shaping Passivity-Based Control Strategy

Directory of Open Access Journals (Sweden)

Rui Hou

2017-05-01

Full Text Available Superconducting magnetic energy storage (SMES systems, in which the proportional-integral (PI method is usually used to control the SMESs, have been used in microgrids for improving the control performance. However, the robustness of PI-based SMES controllers may be unsatisfactory due to the high nonlinearity and coupling of the SMES system. In this study, the energy shaping passivity (ESP-based control strategy, which is a novel nonlinear control based on the methodology of interconnection and damping assignment (IDA, is proposed for robustness improvement of SMES systems. A step-by-step design of the ESP-based method considering the robustness of SMES systems is presented. A comparative analysis of the performance between ESP-based and PI control strategies is shown. Simulation and experimental results prove that the ESP-based strategy achieves the stronger robustness toward the system parameter uncertainties than the conventional PI control. Besides, the use of ESP-based control method can reduce the eddy current losses of a SMES system due to the significant reduction of 2nd and 3rd harmonics of superconducting coil DC current.

Fascinating Magnetic Energy Storage Nanomaterials: A Brief Review.

Science.gov (United States)

Sreenivasulu, Kummari V; Srikanth, Vadali V S S

2017-07-10

In this brief review, the importance of nanotechnology in developing novel magnetic energy storage materials is discussed. The discussion covers recent patents on permanent magnetic materials and especially covers processing of permanent magnets (rare-earth and rare-earth free magnets), importance of rare-earth permanent magnets and necessity of rare-earth free permanent magnets. Magnetic energy storage materials are those magnetic materials which exhibit very high energy product (BH)max (where B is the magnetic induction in Gauss (G) whereas H is the applied magnetic field in Oersted (Oe)). (BH)max is the direct measure of the ability of a magnetic material to store energy. In this context, processing of magnetic energy storage composite materials constituted by soft and hard magnetic materials played a predominant role in achieving high (BH)max values due to the exchange coupling phenomenon between the soft and hard magnetic phases within the composite. Magnetic energy storage composites are normally composed of rare-earth magnetic materials as well as rare-earth free magnetic materials. Nanotechnology's influence on the enhancement of energy product due to the exchange coupling phenomenon is of great prominence and therefore discussed in this review. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Coil protection for a utility scale superconducting magnetic energy storage plant

International Nuclear Information System (INIS)

Loyd, R.J.; Schoenung, S.M.; Rogers, J.D.; Hassenzahl, W.V.; Purcell, J.R.

1986-01-01

Superconducting Magnetic Energy Storage (SMES) is proposed for electric utility load leveling. Attractive costs, high diurnal energy efficiency (≥ 92%), and rapid response are advantages relative to other energy storage technologies. Recent industry-led efforts have produced a conceptual design for a 5000 MWh/1000 MW energy storage plant which is technically feasible at commercially attractive estimated costs. The SMES plant design includes a protection system which prevents damage to the magnetic coil if events require a rapid discharge of stored energy. This paper describes the design and operation of the coil protection system, which is primarily passive and uses the thermal capacity of the coil itself to absorb the stored electromagnetic energy

A study of the status and future of superconducting magnetic energy storage in power systems

International Nuclear Information System (INIS)

Xue, X D; Cheng, K W E; Sutanto, D

2006-01-01

Superconducting magnetic energy storage (SMES) systems offering flexible, reliable, and fast acting power compensation are applicable to power systems to improve power system stabilities and to advance power qualities. The authors have summarized researches on SMES applications to power systems. Furthermore, various SMES applications to power systems have been described briefly and some crucial schematic diagrams and equations are given. In addition, this study presents valuable suggestions for future studies of SMES applications to power systems. Hence, this paper is helpful for co-researchers who want to know about the status of SMES applications to power systems. (topical review)

Large Superconducting Magnet Systems

CERN Document Server

Védrine, P.

2014-07-17

The increase of energy in accelerators over the past decades has led to the design of superconducting magnets for both accelerators and the associated detectors. The use of Nb−Ti superconducting materials allows an increase in the dipole field by up to 10 T compared with the maximum field of 2 T in a conventional magnet. The field bending of the particles in the detectors and generated by the magnets can also be increased. New materials, such as Nb$_{3}$Sn and high temperature superconductor (HTS) conductors, can open the way to higher fields, in the range 13–20 T. The latest generations of fusion machines producing hot plasma also use large superconducting magnet systems.

Large Superconducting Magnet Systems

Energy Technology Data Exchange (ETDEWEB)

Védrine, P [Saclay (France)

2014-07-01

The increase of energy in accelerators over the past decades has led to the design of superconducting magnets for both accelerators and the associated detectors. The use of Nb−Ti superconducting materials allows an increase in the dipole field by up to 10 T compared with the maximum field of 2 T in a conventional magnet. The field bending of the particles in the detectors and generated by the magnets can also be increased. New materials, such as Nb3Sn and high temperature superconductor (HTS) conductors, can open the way to higher fields, in the range 13–20 T. The latest generations of fusion machines producing hot plasma also use large superconducting magnet systems.

Energy efficiency of the CTX magnetized coaxial plasma source

International Nuclear Information System (INIS)

Fernandez, J.C.; Barnes, C.W.; Jarboe, T.R.; Knox, S.O.; Platts, D.A.; McKenna, K.F.

1985-01-01

The energy efficiency of the CTX coaxial plasma source in creating spheromaks is determined experimentally to be in agreement with the theoretical prediction of lambda/sub sp//lambda/sub g/, where del x B = lambda/sub sp/ B in the spheromak, and lambda/sub g/ identical with μ 0 I/sub g//phi/sub g/ with I/sub g/ the source current and phi/sub g/ the magnetic flux through either source electrode. This is shown to be equivalent to magnetic helicity conservation. The spheromak impurity radiation was measured using an absolutely calibrated single chord bolometer system. The theoretical efficiency is within the experimental uncertainty of the ratio of spheromak radiated energy to source input energy in a group of ''dirty'' discharges. But the radiation measurement uncertainty is too large to determine whether a substantial part of the excess source energy not used in the production of spheromak magnetic energy is radiated from the spheromak volume

1-GWh diurnal load-leveling superconducting magnetic energy storage system reference design

International Nuclear Information System (INIS)

Hassenzahl, W.V.; Rogers, J.D.

1979-01-01

A point reference design has been completed for a 1-GWh Superconducting Magnetic Energy Storage system. The system is for electric utility dirunal load leveling; however, such a device will function to meet much faster power demands including dynamic stabilization. The study has explored several concepts of design not previously considered in the same detail as treated here. Because the study is for a point design, optimization in all respects is not complete. The study examines aspects of the coil design; superconductor supported off of the dewar shell; the dewar shell, its configuration and stresses; the underground excavation and related construction for holding the superconducting coil and its dewar; the helium refrigeration system; the electrical converter system; the vacuum system; the guard coil; and the costs. The report is a condensation of the more comprehensive study which is in the process of being printed

Structural analysis of magnetic fusion energy systems in a combined interactive/batch computer environment

International Nuclear Information System (INIS)

Johnson, N.E.; Singhal, M.K.; Walls, J.C.; Gray, W.H.

1979-01-01

A system of computer programs has been developed to aid in the preparation of input data for and the evaluation of output data from finite element structural analyses of magnetic fusion energy devices. The system utilizes the NASTRAN structural analysis computer program and a special set of interactive pre- and post-processor computer programs, and has been designed for use in an environment wherein a time-share computer system is linked to a batch computer system. In such an environment, the analyst must only enter, review and/or manipulate data through interactive terminals linked to the time-share computer system. The primary pre-processor programs include NASDAT, NASERR and TORMAC. NASDAT and TORMAC are used to generate NASTRAN input data. NASERR performs routine error checks on this data. The NASTRAN program is run on a batch computer system using data generated by NASDAT and TORMAC. The primary post-processing programs include NASCMP and NASPOP. NASCMP is used to compress the data initially stored on magnetic tape by NASTRAN so as to facilitate interactive use of the data. NASPOP reads the data stored by NASCMP and reproduces NASTRAN output for selected grid points, elements and/or data types

Active transfer of poloidal magnetic energy during plasma disruptions in J-TEXT

International Nuclear Information System (INIS)

Zhang, Ming; Zhang, Jun; Rao, Bo; Chen, Zhongyong; Li, Xiaolong; Xu, Wendi; Pan, Yuan; Yu, Kexun

2016-01-01

Highlights: • An alternative plasma disruption mitigation method by transferring partial poloidal magnetic energy out of the vacuum vessel has been presented in this paper. • This method can reduced the magnetic energy dissipated inside the vacuum vessel during disruption and mitigated the disruption damage. • This method has been experimentally verified in J-TEXT with an experiment system set up. • According to the experimental results, the magnetic energy dissipated inside the vacuum vessel during disruption can be reduced by 20% or more and the loop voltage can be reduced by 58%. - Abstract: The magnitude of the damaging effects of plasma disruptions on vacuum vessel (VV) components increases with the thermal energy and poloidal magnetic energy dissipated inside the VV. This study focuses on an alternative method, by which partial poloidal magnetic energy is transferred out of the VV. The quantity of the poloidal magnetic energy dissipated inside the VV (W_d_i_s) can be reduced with this method, and the damaging effects can be mitigated. Partial magnetic energy is transferred based on magnetic coupling by a group of energy transfer coils (ETCs) that are coupled with the plasma current. This method, which is called magnetic energy transfer (MET), has been experimentally verified in J-TEXT. W_d_i_s can be reduced by approximately 20%, and the loop voltage can be reduced by 58%. MET is established as a novel, promising, and effective plasma disruption mitigation method.

High-Energy Beam Transport system

International Nuclear Information System (INIS)

Melson, K.E.; Farrell, J.A.; Liska, D.J.

1979-01-01

The High-Energy Beam Transport (HEBT) system for the Fusion Materials Irradiation Test (FMIT) Facility is to be installed at the Hanford Engineering Development Laboratory (HEDL) at Richland, Washington. The linear accelerator must transport a large emittance, high-current, high-power, continuous-duty deuteron beam with a large energy spread either to a lithium target or a beam stop. A periodic quadrupole and bending-magnet system provides the beam transport and focusing on target with small beam aberrations. A special rf cavity distributes the energy in the beam so that the Bragg Peak is distributed within the lithium target. Operation of the rf control system, the Energy Dispersion Cavity (EDC), and the beam transport magnets is tested on the beam stop during accelerator turn-on. Characterizing the beam will require extensions of beam diagnostic techniques and noninterceptive sensors. Provisions are being made in the facility for suspending the transport system from overhead supports using a cluster system to simplify maintenance and alignment techniques

MAXIMIZING MAGNETIC ENERGY STORAGE IN THE SOLAR CORONA

International Nuclear Information System (INIS)

Wolfson, Richard; Drake, Christina; Kennedy, Max

2012-01-01

The energy that drives solar eruptive events such as coronal mass ejections (CMEs) almost certainly originates in coronal magnetic fields. Such energy may build up gradually on timescales of days or longer before its sudden release in an eruptive event, and the presence of free magnetic energy capable of rapid release requires nonpotential magnetic fields and associated electric currents. For magnetic energy to power a CME, that energy must be sufficient to open the magnetic field to interplanetary space, to lift the ejecta against solar gravity, and to accelerate the material to speeds of typically several hundred km s –1 . Although CMEs are large-scale structures, many originate from relatively compact active regions on the solar surface—suggesting that magnetic energy storage may be enhanced when it takes place in smaller magnetic structures. This paper builds on our earlier work exploring energy storage in large-scale dipolar and related bipolar magnetic fields. Here we consider two additional cases: quadrupolar fields and concentrated magnetic bipoles intended to simulate active regions. Our models yield stored energies whose excess over that of the corresponding open field state can be greater than 100% of the associated potential field energy; this contrasts with maximum excess energies of only about 20% for dipolar and symmetric bipolar configurations. As in our previous work, energy storage is enhanced when we surround a nonpotential field with a strong overlying potential field that acts to 'hold down' the nonpotential flux as its magnetic energy increases.

Design of magnetic analysis system for magnetic proton recoil spectrometer

International Nuclear Information System (INIS)

Qi Jianmin; Jiang Shilun; Zhou Lin; Peng Taiping

2010-01-01

Magnetic proton recoil (MPR) spectrometer is a novel diagnostic instrument with high performance for measurements of the neutron spectra from inertial confinement fusion (ICF) experiments and high power fusion devices. The design of the magnetic analysis system, which is a key part of the compact MPR-type spectrometer, has been completed through two-dimensional beam transport simulations and three-dimensional particle transport simulation. The analysis of the system's parameters and performances was performed, as well as system designs based on preferential principles of energy resolution, detection efficiency, and count rate, respectively. The results indicate that the magnetic analysis system can achieve a detection efficiency of 10 -5 ∼ 10 -4 level at the resolution range of 1.5% to 3.0% and fulfill the design goals of the compact MPR spectrometer. (authors)

Superconducting magnets in nuclear and high energy physics

International Nuclear Information System (INIS)

Hamelin, J.; Parain, J.; Perot, J.; Lesmond, C.

1976-01-01

A few examples of superconducting magnets developped at Saclay for high energy physics are presented. The OGA doublet is a large acceptance optical system consisting of two quadrupoles with maximum field gradients of 35 and 23 teslas per meter giving an increase of the beam acceptance by a factor 4. The ALEC dipole is a synchrotron magnet with a length of 1.5 meter and a field of 5 teslas, operating in pulse made at a frequency of 0.1 Hertz and entirely constructed in industry. The ECO project is a demonstration of electrical energy saving by means of superconductors. It consists in the replacement of conventional copper of a classical beam transport magnet by superconducting windings. The use of superconductors for polarized target magnets allows a large variety of configurations to be obtained in order to satisfy the acceptance and space requirements to the detectors around the targets [fr

Globally Optimal Segmentation of Permanent-Magnet Systems

DEFF Research Database (Denmark)

Insinga, Andrea Roberto; Bjørk, Rasmus; Smith, Anders

2016-01-01

Permanent-magnet systems are widely used for generation of magnetic fields with specific properties. The reciprocity theorem, an energy-equivalence principle in magnetostatics, can be employed to calculate the optimal remanent flux density of the permanent-magnet system, given any objective...... remains unsolved. We show that the problem of optimal segmentation of a two-dimensional permanent-magnet assembly with respect to a linear objective functional can be reduced to the problem of piecewise linear approximation of a plane curve by perimeter maximization. Once the problem has been cast...

Free Magnetic Energy in Solar Active Regions above the Minimum-Energy Relaxed State

OpenAIRE

Regnier, S.; Priest, E. R.

2008-01-01

To understand the physics of solar flares, including the local reorganization of the magnetic field and the acceleration of energetic particles, we have first to estimate the free magnetic energy available for such phenomena, which can be converted into kinetic and thermal energy. The free magnetic energy is the excess energy of a magnetic configuration compared to the minimum-energy state, which is a linear force-free field if the magnetic helicity of the configuration is conserved. We inves...

A multifunctional energy-saving magnetic field generator

Science.gov (United States)

Xiong, Hui; Sun, Wanpeng; Liu, Jinzhen; Shi, Jinhua

2018-03-01

To improve the energy utilization of magnetic field generators for biological applications, a multifunctional energy-saving magnetic field generator (ESMFG) is presented. It is capable of producing both an alternating magnetic field (AMF) and a bipolar pulse magnetic field (BPMF) with high energy-saving and energy-reuse rates. Based on a theoretical analysis of an RLC second-order circuit, the energy-saving and energy-reuse rates of both types of magnetic fields can be calculated and are found to have acceptable values. The results of an experimental study using the proposed generator show that for the BPMF, the peak current reaches 130 A and the intensity reaches 70.3 mT. For the AMF, the intensity is 11.0 mT and the RMS current is 20 A. The energy-saving and energy-reuse rates for the AMF generator are 61.3% and 63.5%, respectively, while for the BPMF generator, the energy-saving rate is 33.6%. Thus, the proposed ESMFG has excellent potential for use in biomedical applications.

Efficient energy transfer and increase of energy density of magnetically charged flywheels

International Nuclear Information System (INIS)

Hinterdorfer, T.

2014-01-01

Flywheel Energy Storage Systems represent an ecologically and economically sustainable technology for decentralized energy storage. Compared to other storage technologies such as e.g. chemical accumulators, they offer longer life cycles without performance degradation over time and usage and need almost no systematic maintenance. Further, they are made of environmentally friendly materials. By means of the driving torque of an electric motor, the flywheel is accelerated and thus electrical energy is transformed to kinetic energy. The stored energy can be transfered back by the load torque of a generator when needed. Modern flywheel energy storage applications use magnetic bearings to minimize selfdischarge. To avoid bearing forces due to rotor eccentricity an unbalance control strategy is used. However, this leads to an off-centered run of the electric machines rotor which in turn generates undesirable forces. A force-compensating operation of the electric machine will minimize the influence on the magnetic bearings in the planned control scheme, thus increasing their efficiency. Different concepts will be developed and compared to each other by means of simulations. Validation of the simulation models is carried out on a specially constructed test setup under defined conditions. In addition, the electrical machine will be integrated into the concept of redundancy of the flywheel. A bearingless operation increases the reliability and enables a safe shutdown of the application in case of malfunction of the magnetic bearings. High strength composite materials are used to achieve high speeds. Based on existing results from past research activities, a disc-shaped rotor is optimized first. To increase material utilization and to maximize energy density a topology optimization is performed. Evolutionary and gradient based optimization algorithms are used. Thereby the unused strength potential of the material is exploited in order to increase the economic efficiency of

Magnetic levitation in orbitron system

International Nuclear Information System (INIS)

Zub, S.S.

2014-01-01

This paper devoted to proof the existence of stable quasi-periodic motions of the magnetic dipole that is under the action of the external magnetic field and homogeneous field of gravity. For proof we used energy-momentum method that is the group-theoretic method of Hamiltonian mechanics. Numerical simulation shows the possibility of realization of stable motions with physically reasonable parameters of the system.

Rare earth magnets with high energy products

International Nuclear Information System (INIS)

Hirosawa, S.; Kaneko, Y.

1998-01-01

High energy-products exceeding 430 kj/m 3 (54 MGOe) have been realized on anisotropic permanent magnets based on the Nd 2 Fe 14 B phase, recently. To produce extremely high-energy-product permanent magnets, special processes have been designed in order to realize the minimum oxygen content, the maximum volume fraction of the hard magnetic Nd 2 Fe 14 B phase, the highest orientation of the easy axis of magnetization, and small and homogeneous crystalline grain sizes in the finished magnets. For the powder metallurgical process, special techniques such as low-oxygen fine powder processing and magnetic alignment using pulsed magnetic fields have been developed. It has been shown that a good control of both homogeneity of distribution of constituent phases and the narrowness of the size distribution in the starting powder have great influences on the magnetic energy products. It is emphasized that the recently developed techniques are applicable in a large-scale production, meaning that extremely high-energy-product magnets are available on commercial basis. (orig.)

A Miniature Magnetic-Force-Based Three-Axis AC Magnetic Sensor with Piezoelectric/Vibrational Energy-Harvesting Functions

Directory of Open Access Journals (Sweden)

Chiao-Fang Hung

2017-02-01

Full Text Available In this paper, we demonstrate a miniature magnetic-force-based, three-axis, AC magnetic sensor with piezoelectric/vibrational energy-harvesting functions. For magnetic sensing, the sensor employs a magnetic–mechanical–piezoelectric configuration (which uses magnetic force and torque, a compact, single, mechanical mechanism, and the piezoelectric effect to convert x-axis and y-axis in-plane and z-axis magnetic fields into piezoelectric voltage outputs. Under the x-axis magnetic field (sine-wave, 100 Hz, 0.2–3.2 gauss and the z-axis magnetic field (sine-wave, 142 Hz, 0.2–3.2 gauss, the voltage output with the sensitivity of the sensor are 1.13–26.15 mV with 8.79 mV/gauss and 1.31–8.92 mV with 2.63 mV/gauss, respectively. In addition, through this configuration, the sensor can harness ambient vibrational energy, i.e., possessing piezoelectric/vibrational energy-harvesting functions. Under x-axis vibration (sine-wave, 100 Hz, 3.5 g and z-axis vibration (sine-wave, 142 Hz, 3.8 g, the root-mean-square voltage output with power output of the sensor is 439 mV with 0.333 μW and 138 mV with 0.051 μW, respectively. These results show that the sensor, using this configuration, successfully achieves three-axis magnetic field sensing and three-axis vibration energy-harvesting. Due to these features, the three-axis AC magnetic sensor could be an important design reference in order to develop future three-axis AC magnetic sensors, which possess energy-harvesting functions, for practical industrial applications, such as intelligent vehicle/traffic monitoring, processes monitoring, security systems, and so on.

Superconducting magnets for high energy storage rings

International Nuclear Information System (INIS)

Sampson, W.B.

1977-01-01

Superconducting dipole and quadrupole magnets were developed for the proton-proton intersecting storage accelerator ISABELLE. Full size prototypes of both kinds of magnets were constructed and successfully tested. The coils are fabricated from a single layer of wide braided superconductor and employ a low temperature iron core. This method of construction leads to two significant performance advantages; little or no training, and the ability of the coil to absorb its total magnetic stored energy without damage. A high pressure (15 atm) helium gas system is used for cooling. Measurements of the random field errors are compared with the expected field distribution. Three magnets (two dipoles and one quadrupole) were assembled into a segment of the accelerator ring structure (half cell). The performance of this magnet array, which is coupled in series both electrically and cryogenically, is also summarized

Neutron scattering investigation of magnetic excitations at high energy transfers

International Nuclear Information System (INIS)

Loong, C.K.

1984-01-01

With the advance of pulsed spallation neutron sources, neutron scattering investigation of elementary excitations in magnetic materials can now be extended to energies up to several hundreds of MeV. We have measured, using chopper spectrometers and time-of-flight techniques, the magnetic response functions of a series of d and f transition metals and compounds over a wide range of energy and momentum transfer. In PrO 2 , UO 2 , BaPrO 3 and CeB 6 we observed crystal-field transitions between the magnetic ground state and the excited levels in the energy range from 40 to 260 MeV. In materials exhibiting spin-fluctuation or mixed-valent character such as Ce 74 Th 26 , on the other hand, no sharp crystal-field lines but a broadened quasielastic magnetic peak was observed. The line width of the quasielastic component is thought to be connected to the spin-fluctuation energy of the 4f electrons. The significance of the neutron scattering results in relation to the ground state level structure of the magnetic ions and the spin-dynamics of the f electrons is discussed. Recently, in a study of the spin-wave excitations in itinerant magnetic systems, we have extended the spin-wave measurements in ferromagnetic iron up to about 160 MeV. Neutron scattering data at high energy transfers are of particular interest because they provide direct comparison with recent theories of itinerant magnetism. 26 references, 7 figures

Superconducting magnets in the world of energy, especially in fusion power

International Nuclear Information System (INIS)

Komarek, P.

1976-01-01

Industrial applications of superconducting magnets are only feasible in the near future for superconducting monopolar machines and possible MHD generators. For superconducting synchronous machines, after the successful operation of machines in the MVA range, a new phase of basic investigations has started. Fundamental problems which could not be studied in the MVA machines, but which influence the design of large turbo-alternators, must now be investigated. Fusion power by magnetic confinement will probably be the largest field of application for superconducting magnets in the long run. The present research programmes require large superconducting magnets by the mid-1980s for the experimental reactors envisaged at that time. In addition to dc windings, pulse-operated superconducting windings are required in some systems, such as Tokamak. The high sensitivity of the overall plant efficiency and the active power demand of the pulsed windings require great efficiency from energy storage and transfer systems. Superconducting energy storage systems would be suitable for this, if transfer between inductances could be provided with sufficient efficiency. Basic experiments gave encouraging results. In power plant systems and electric machines an extremely high level of reliability and availability has been achieved. Less reliability will not be accepted for systems with superconducting magnets. This requires great efforts during the development work. (author)

Gaussian optics calculations of the parameters of a magnetic sector energy analyzer

International Nuclear Information System (INIS)

Zaluzec, N.J.

1978-01-01

The design of a magnetic deflection system for use as an electron energy loss spectrometer can be a complex process if one takes the most general approach. However, for application to materials research the design process can be reduced to three basic steps. First, the qualitative features of the overall system are defined--i.e., incident electron energy, required resolution, type of magnet, the desired focal properties, etc. Secondly, the design parameters necessary to meet these requirements are calculated using the appropriate equations. Finally, once the magnetic field has been specified, ray-tracing techniques can be employed to verify the system response to the conditions defined in the first two steps. The calculation of the parameters of a uniform field magnetic sector analyzer capable of energy resolutions of 20 ppM or better are considered. Higher resolution is attainable; however, for most materials work, more important considerations are the attainment of double focusing to improve S/N, the minimization of aberrations and the achievement of a flat image plane to facilitate parallel data recording

Tunable evolutions of shock absorption and energy partitioning in magnetic granular chains

Science.gov (United States)

Leng, Dingxin; Liu, Guijie; Sun, Lingyu

2018-01-01

In this paper, we investigate the tunable characteristics of shock waves propagating in one-dimensional magnetic granular chains at various chain lengths and magnetic flux densities. According to the Hertz contact theory and Maxwell principle, a discrete element model with coupling elastic and field-induced interaction potentials of adjacent magnetic grains is proposed. We also present hard-sphere approximation analysis to describe the energy partitioning features of magnetic granular chains. The results demonstrate that, for a fixed magnetic field strength, when the chain length is greater than two times of the wave width of the solitary wave, the chain length has little effect on the output energy of the system; for a fixed chain length, the shock absorption and energy partitioning features of magnetic granular chains are remarkably influenced by varying magnetic flux densities. This study implies that the magnetic granular chain is potential to construct adaptive shock absorption components for impulse mitigation.

Compact and energy saving magnet technology for particle accelerators

International Nuclear Information System (INIS)

Baurichter, A.

2013-01-01

Despite the fact that funding agencies and industrial users of particle accelerators get more and more alerted about costs of civil engineering, installation and operation, only little effort has been put into development of sustainable, energy and cost saving accelerator technology. In order to reduce the total-cost-of ownership of accelerator magnets, operating at high electrical power for twenty years or more, permanent magnet based Green Magnet technology has been developed at a consortium around Danfysik's R and D team. Together with our partners from ISA, Aarhus University, the Aarhus School of Engineering, the company Sintex and Aalborg University all obstacles in applying permanent magnet technology as e.g. thermal drift and inhomogeneities of magnetic fields have been overcome. The first Green Magnet has now been operated for more than half a year in an Accelerator Mass Spectrometry facility at the ETH in Zurich. The performance of this B=0.43T 90 deg. H-type bending magnet and the most recently builtB=1T, 30 deg. C-type Green Magnet for the synchrotron light source ASTRID2 at ISA in Aarhus will be presented. Danfysik also is designing, manufacturing and testing 60 compact magnet systems, developed at MAX-Lab for the new MAXIV 3.0 GeV synchrotron light source. In addition, 12 for the 1.5 GeV light source and another 12 for the new SOLARIS light source in Krakow, Poland are buying built. Up to a dozen or more magnet functions have been integrated into one yoke of these compact magnet systems, which makes the new MAXIV light sources compact, energy saving and at the same time very bright. Test results and design concepts of the new MAXIV and SOLARIS magnets will be presented. (author)

Energy transfers in dynamos with small magnetic Prandtl numbers

KAUST Repository

Kumar, Rohit

2015-06-25

We perform numerical simulation of dynamo with magnetic Prandtl number Pm = 0.2 on 10243 grid, and compute the energy fluxes and the shell-to-shell energy transfers. These computations indicate that the magnetic energy growth takes place mainly due to the energy transfers from large-scale velocity field to large-scale magnetic field and that the magnetic energy flux is forward. The steady-state magnetic energy is much smaller than the kinetic energy, rather than equipartition; this is because the magnetic Reynolds number is near the dynamo transition regime. We also contrast our results with those for dynamo with Pm = 20 and decaying dynamo. © 2015 Taylor & Francis.

Superconducting Magnetic Energy Storage

International Nuclear Information System (INIS)

Hassenzahl, W.

1989-01-01

Recent programmatic developments in Superconducting Magnetic Energy Storage (SMES) have prompted renewed and widespread interest in this field. In mid 1987 the Defense Nuclear Agency, acting for the Strategic Defense Initiative Office issued a request for proposals for the design and construction of SMES Engineering Test Model (ETM). Two teams, one led by Bechtel and the other by Ebasco, are now engaged in the first phase of the development of a 10 to 20 MWhr ETM. This report presents the rationale for energy storage on utility systems, describes the general technology of SMES, and explains the chronological development of the technology. The present ETM program is outlined; details of the two projects for ETM development are described in other papers in these proceedings. The impact of high Tc materials on SMES is discussed

Fusion magnet safety studies program: superconducting magnet protection system and failure. Interim report

International Nuclear Information System (INIS)

Allinger, J.; Danby, G.; Hsieh, S.Y.; Keane, J.; Powell, J.; Prodell, A.

1975-11-01

This report includes the first two quarters study of available information on schemes for protecting superconducting magnets. These schemes can be divided into two different categories. The first category deals with the detection of faulty regions (or normal regions) in the magnet. The second category relates to the protection of the magnet when a fault is detected, and the derived signal which can be used to activate a safety system (or energy removal system). The general detection and protection methods are first described briefly and then followed by a survey of the protection systems used by different laboratories for various magnets. A survey of the cause of the magnet difficulties or failures is also included. A preliminary discussion of these protection schemes and the experimental development of this program is given

ENERGY DISSIPATION IN MAGNETIC NULL POINTS AT KINETIC SCALES

International Nuclear Information System (INIS)

Olshevsky, Vyacheslav; Lapenta, Giovanni; Divin, Andrey; Eriksson, Elin; Markidis, Stefano

2015-01-01

We use kinetic particle-in-cell and MHD simulations supported by an observational data set to investigate magnetic reconnection in clusters of null points in space plasma. The magnetic configuration under investigation is driven by fast adiabatic flux rope compression that dissipates almost half of the initial magnetic field energy. In this phase powerful currents are excited producing secondary instabilities, and the system is brought into a state of “intermittent turbulence” within a few ion gyro-periods. Reconnection events are distributed all over the simulation domain and energy dissipation is rather volume-filling. Numerous spiral null points interconnected via their spines form null lines embedded into magnetic flux ropes; null point pairs demonstrate the signatures of torsional spine reconnection. However, energy dissipation mainly happens in the shear layers formed by adjacent flux ropes with oppositely directed currents. In these regions radial null pairs are spontaneously emerging and vanishing, associated with electron streams and small-scale current sheets. The number of spiral nulls in the simulation outweighs the number of radial nulls by a factor of 5–10, in accordance with Cluster observations in the Earth's magnetosheath. Twisted magnetic fields with embedded spiral null points might indicate the regions of major energy dissipation for future space missions such as the Magnetospheric Multiscale Mission

Non-equilibrium magnetic interactions in strongly correlated systems

Energy Technology Data Exchange (ETDEWEB)

Secchi, A., E-mail: a.secchi@science.ru.nl [Institute for Molecules and Materials, Radboud University Nijmegen, 6525 AJ Nijmegen (Netherlands); Brener, S.; Lichtenstein, A.I. [Institut für Theoretische Physik, Universitat Hamburg, Jungiusstraße 9, D-20355 Hamburg (Germany); Katsnelson, M.I. [Institute for Molecules and Materials, Radboud University Nijmegen, 6525 AJ Nijmegen (Netherlands)

2013-06-15

We formulate a low-energy theory for the magnetic interactions between electrons in the multi-band Hubbard model under non-equilibrium conditions determined by an external time-dependent electric field which simulates laser-induced spin dynamics. We derive expressions for dynamical exchange parameters in terms of non-equilibrium electronic Green functions and self-energies, which can be computed, e.g., with the methods of time-dependent dynamical mean-field theory. Moreover, we find that a correct description of the system requires, in addition to exchange, a new kind of magnetic interaction, that we name twist exchange, which formally resembles Dzyaloshinskii–Moriya coupling, but is not due to spin–orbit, and is actually due to an effective three-spin interaction. Our theory allows the evaluation of the related time-dependent parameters as well. -- Highlights: •We develop a theory for magnetism of strongly correlated systems out of equilibrium. •Our theory is suitable for laser-induced ultrafast magnetization dynamics. •We write time-dependent exchange parameters in terms of electronic Green functions. •We find a new magnetic interaction, a “twist exchange”. •We give general expressions for magnetic noise in itinerant-electron systems.

Numerical analyses of magnetic field and force in toroidal superconducting magnetic energy storage using unit coils (abstract)

International Nuclear Information System (INIS)

Kanamaru, Y.; Nakayama, T.; Amemiya, Y.

1997-01-01

Superconducting magnetic energy storage (SMES) is more useful than other systems of electric energy storage because of its larger amounts of stored energy and its higher efficiency. There are two types of SMES. One is the solenoid type and the other is the toroidal type. Some models of solenoid-type SMES are designed in the U.S. and in Japan. But the large scale SMES causes a high magnetic field in the living environment, and causes the erroneous operation of electronic equipment. The authors studied some suitable designs of magnetic shielding for the solenoidal-type SMES to reduce the magnetic field in the living environment. The toiroidal type SMES is studied in this article. The magnetic leakage flux of the toiroidal-type SMES is generally lower than that of the solenoid-type SMES. The toroidal-type SMES is constructed of unit coils, which are convenient for construction. The magnetic leakage flux occurs between unit coils. The electromagnetic force of the coils is very strong. Therefore analyses of the leakage flux and electromagnetic force are important to the design of SMES. The authors studied the number, radius, and length of unit coils. The storage energy is 5 G Wh. The numerical analyses of magnetic fields in the toroidal type SMES are obtained by analytical solutions. copyright 1997 American Institute of Physics

Energy consumption of magnetic-levitation train systems

Energy Technology Data Exchange (ETDEWEB)

Mayer, W J

1981-11-01

In transport, interest is at present being directed to the energy consumption of the various systems. The 'maglev' system is not yet in practical transport use, so that many characteristics of the system have still to be proven. Calculations show, however, that the 'maglev' train system can meet or even exceed the high requirements familiar to us from the conventional railway. Among the assumptions made with respect to speed, acceleration, distance between halts and capacity utilization it can be shown by calculation that the 'maglev' system is more economical in energy consumption than most existing passenger transport systems. A final judgement on the still existing uncertainties with respect to the traction resistance curve and the motor efficiency can only be made after the experimental 'maglev' layout now being built in Emsland has gone into operation.

Wireless Energy Transfer Through Magnetic Reluctance Coupling

International Nuclear Information System (INIS)

Pillatsch, P

2014-01-01

Energy harvesting from human motion for body worn or implanted devices faces the problem of the wearer being still, e.g. while asleep. Especially for medical devices this can become an issue if a patient is bed-bound for prolonged periods of time and the internal battery of a harvesting system is not recharged. This article introduces a mechanism for wireless energy transfer based on a previously presented energy harvesting device. The internal rotor of the energy harvester is made of mild steel and can be actuated through a magnetic reluctance coupling to an external motor. The internal piezoelectric transducer is consequently actuated and generates electricity. This paper successfully demonstrates energy transfer over a distance of 16 mm in air and an achieved power output of 85 μW at 25 Hz. The device functional volume is 1.85 cm 3 . Furthermore, it was demonstrated that increasing the driving frequency beyond 25 Hz did not yield a further increase in power output. Future research will focus on improving the reluctance coupling, e.g. by investigating the use of multiple or stronger magnets, in order to increase transmission distance

Optimization of HTS superconducting magnetic energy storage magnet volume

Science.gov (United States)

Korpela, Aki; Lehtonen, Jorma; Mikkonen, Risto

2003-08-01

Nonlinear optimization problems in the field of electromagnetics have been successfully solved by means of sequential quadratic programming (SQP) and the finite element method (FEM). For example, the combination of SQP and FEM has been proven to be an efficient tool in the optimization of low temperature superconductors (LTS) superconducting magnetic energy storage (SMES) magnets. The procedure can also be applied for the optimization of HTS magnets. However, due to a strongly anisotropic material and a slanted electric field, current density characteristic high temperature superconductors HTS optimization is quite different from that of the LTS. In this paper the volumes of solenoidal conduction-cooled Bi-2223/Ag SMES magnets have been optimized at the operation temperature of 20 K. In addition to the electromagnetic constraints the stress caused by the tape bending has also been taken into account. Several optimization runs with different initial geometries were performed in order to find the best possible solution for a certain energy requirement. The optimization constraints describe the steady-state operation, thus the presented coil geometries are designed for slow ramping rates. Different energy requirements were investigated in order to find the energy dependence of the design parameters of optimized solenoidal HTS coils. According to the results, these dependences can be described with polynomial expressions.

Generation of intense, high-energy ion pulses by magnetic compression of ion rings

International Nuclear Information System (INIS)

Kapetanakos, C.A.

1981-01-01

A system based on the magnetic compression of ion rings, for generating intense (High-current), high-energy ion pulses that are guided to a target without a metallic wall or an applied external magnetic field includes a vacuum chamber; an inverse reflex tetrode for producing a hollow ion beam within the chamber; magnetic coils for producing a magnetic field, bo, along the axis of the chamber; a disc that sharpens a magnetic cusp for providing a rotational velocity to the beam and causing the beam to rotate; first and second gate coils for producing fast-rising magnetic field gates, the gates being spaced apart, each gate modifying a corresponding magnetic mirror peak (Near and far peaks) for trapping or extracting the ions from the magnetic mirror, the ions forming a ring or layer having rotational energy; a metal liner for generating by magnetic flux compression a high, time-varying magnetic field, the time-varying magnetic field progressively increasing the kinetic energy of the ions, the magnetic field from the second gate coil decreasing the far mirror peak at the end of the compression for extracting the trapped rotating ions from the confining mirror; and a disc that sharpens a magnetic half-cusp for increasing the translational velocity of the ion beam. The system utilizes the self-magnetic field of the rotating, propagating ion beam to prevent the beam from expanding radially upon extraction

1-GWh diurnal load-leveling Superconducting Magnetic Energy Storage system reference design

International Nuclear Information System (INIS)

Rogers, J.D.; Hassenzahl, W.V.; Schermer, R.I.

1979-09-01

A point reference design has been completed for a 1-GWh Superconducting Magnetic Energy Storage system. The system is for electric utility diurnal load-leveling but can also function to meet much faster power demands including dynamic stabilization. This study explores several concepts of design not previously considered in the same detail as treated here. Because the study is for a point design, optimization in all respects is not complete. This report examines aspects of the coil, the superconductor supported off of the dewar shell, the dewar shell, and its configuration and stresses, the underground excavation and construction for holding the superconducting coil and its dewar, the helium refrigeration system, the electrical converter system, the vacuum system, the guard coil, and the costs. This report is divided into two major portions. The first is a general treatment of the work and the second is seven detailed technical appendices issued as separate reports. The information presented on the aluminum stabilizer for the conductor, on the excavation, and on the converter is based upon industrial studies contracted for this work

Estimating the magnetic energy inside traveling compression regions

Directory of Open Access Journals (Sweden)

S. A. Kiehas

2009-05-01

Full Text Available We investigate a series of six TCRs (traveling compression regions, appearing in the course of a small substorm on 19 September 2001. Except for two of these TCRs, all Cluster spacecraft were located in the lobe and detected the typical signatures of TCRs, i.e., compressions in |B| and bipolar Bz variations. We use these perturbations in Bz for calculations on the magnetic energy inside the TCR and compare the amount of magnetic field energy with the kinetic energy inside the underlying plasma bulge. According to results obtained from theory, the amount of magnetic energy inside TCRs is about two times higher than the kinetic plasma energy inside the accompanied plasma bulge. We verify this theoretical result by first investigations of the magnetic field energy inside TCRs. The calculations lead to a magnetic energy in the order of 1010 Joule per RE for each of the TCRs.

MAGNETIC ENERGY BUILDUP FOR RELATIVISTIC MAGNETAR GIANT FLARES

International Nuclear Information System (INIS)

Yu Cong

2011-01-01

Motivated by coronal mass ejection studies, we construct general relativistic models of a magnetar magnetosphere endowed with strong magnetic fields. The equilibrium states of the stationary, axisymmetric magnetic fields in the magnetar magnetosphere are obtained as solutions of the Grad-Shafranov equation in a Schwarzschild spacetime. To understand the magnetic energy buildup in the magnetar magnetosphere, a generalized magnetic virial theorem in the Schwarzschild metric is newly derived. We carefully address the question whether the magnetar magnetospheric magnetic field can build up sufficient magnetic energy to account for the work required to open up the magnetic field during magnetar giant flares. We point out the importance of the Aly-Sturrock constraint, which has been widely studied in solar corona mass ejections, as a reference state in understanding magnetar energy storage processes. We examine how the magnetic field can possess enough energy to overcome the Aly-Sturrock energy constraint and open up. In particular, general relativistic (GR) effects on the Aly-Sturrock energy constraint in the Schwarzschild spacetime are carefully investigated. It is found that, for magnetar outbursts, the Aly-Sturrock constraint is more stringent, i.e., the Aly-Sturrock energy threshold is enhanced due to the GR effects. In addition, neutron stars with greater mass have a higher Aly-Sturrock energy threshold and are more difficult to erupt. This indicates that magnetars are probably not neutron stars with extreme mass. For a typical neutron star with mass of 1-2 M sun , we further explore the cross-field current effects, caused by the mass loading, on the possibility of stored magnetic field energy exceeding the Aly-Sturrock threshold.

Modeling of switching energy of magnetic tunnel junction devices with tilted magnetization

International Nuclear Information System (INIS)

Surawanitkun, C.; Kaewrawang, A.; Siritaratiwat, A.; Kruesubthaworn, A.; Sivaratana, R.; Jutong, N.; Mewes, C.K.A.; Mewes, T.

2015-01-01

For spin transfer torque (STT), the switching energy and thermal stability of magnetic tunnel junctions (MTJ) bits utilized in memory devices are important factors that have to be considered simultaneously. In this article, we examined the minimum energy for STT induced magnetization switching in MTJ devices for different in-plane angles of the magnetization in the free layer and the pinned layer with respect to the major axis of the elliptical cylinder of the cell. Simulations were performed by comparing the analytical solution with macrospin and full micromagnetic calculations. The results show good agreement of the switching energy calculated by using the three approaches for different initial angles of the magnetization of the free layer. Also, the low-energy location specifies the suitable value of both time and current in order to reduce the heat effect during the switching process. - Highlights: • Switching energy model was firstly examined with tiled magnetization in STT-RAM. • Simulation was performed by analytical solution, macrospin and micromagnetic models. • Low energy results from three models show agreement for tilt angle in free layer. • We also found an optimal tilt angle of the pinned layer. • Low-energy location specifies the suitable switching location to reduce heat effect

Experimental Evaluation of Superconductor Flywheel Energy Storage System with Hybrid Type Active Magnetic Bearing

International Nuclear Information System (INIS)

Lee, J. P.; Kim, H. G.; Han, S. C.

2012-01-01

In this paper, we designed Active Magnetic Bearing (AMB) for large scale Superconductor Flywheel Energy Storage System (SFESS) and PD controller for AMB. And we experimentally evaluated SFESS including hybrid type AMB. The radial AMB was designed to provide force slew rate that was sufficient for the unbalance disturbances at the maximum operating speed. The thrust AMB is a hybrid type where a permanent magnet carries the weight of the flywheel and an electromagnetic actuator generates the dynamic control force. We evaluated the design performance of the manufactured AMB through comparison of FEM analysis and the results of experimental force measurement. In order to obtain gains of PD controller and design a notch filter, the system identification was performed through measuring frequency response including dynamics for the AMBs, a power amp and a sensor using a sine swept test method after levitating the flywheel. Through measuring the current input of the AMBs and the orbit of a flywheel according to rotational speed, we verified excellent control performance of the AMBs with small amount current for the large scale SFESS.

Design of electron beam bending magnet system using three sector magnets for electron and photon therapy: a simulation approach

International Nuclear Information System (INIS)

Shahzad, A.A.; Bhoraskar, V.N.; Dhole, S.D.

2013-01-01

The 270 degree doubly achromatic beam bending magnet system using three sector magnets has been designed mainly for treating cancer and skin diseases. The main requirements of the design of three magnet system is to focus an electron beam having a spot size less than 3mm x 3mm, energy spread within 3% and divergence angle ≤ 3 mrad at the target. To achieve these parameters the simulation was carried out using Lorentz-3EM software. The beam spot, divergence angle and energy spread were observed with respect to the variation in angles of sector magnets and drift distances. From the simulated results, it has been optimized that all the three sector magnets has an angle of 62 degree and the drift distance 68 mm. It is also observed that at the 1637, 2425, 3278, 4165 and 5690 Amp-turn, the optimized design produces 3851, 5754, 7434, 9356 and 11425 Gauss of magnetic field at median plane require to bend 6, 9, 12, 15 and 18 MeV energy of electron respectively for electron therapy. The output parameters of the optimized design are energy spread 3%, divergence angle ∼ 3 mrad and spot size 2.8 mm. Moreover, for 6 MV and 15 MV photon therapy application, an electron beam of energy 6.5 MeV and 15.5 MeV extracted from magnet system and focussed on the Bremsstrahlung target. For the photon therapy the 1780, and 4456 amp-turn, an optimized design produces 4148 and 9682 Gauss of magnetic field at median plane require to bend 6.5 and 15.5 MeV energy of electron respectively, which further produces Bremsstrahlung in Tungsten target. (author)

A permanent magnet electron beam spread system used for a low energy electron irradiation accelerator

International Nuclear Information System (INIS)

Huang Jiang; Xiong Yongqian; Chen Dezhi; Liu Kaifeng; Yang Jun; Li Dong; Yu Tiaoqin; Fan Mingwu; Yang Bo

2014-01-01

The development of irradiation processing industry brings about various types of irradiation objects and expands the irradiation requirements for better uniformity and larger areas. This paper proposes an innovative design of a permanent magnet electron beam spread system. By clarifying its operation principles, the author verifies the feasibility of its application in irradiation accelerators for industrial use with the examples of its application in electron accelerators with energy ranging from 300 keV to 1 MeV. Based on the finite element analyses of electromagnetic fields and the charged particle dynamics, the author also conducts a simulation of electron dynamics in magnetic field on a computer. The results indicate that compared with the traditional electron beam scanning system, this system boosts the advantages of a larger spread area, non-power supply, simple structure and low cost, etc., which means it is not only suitable for the irradiation of objects with the shape of tubes, strips and panels, but can also achieve a desirable irradiation performance on irregular constructed objects of large size. (authors)

Feasibility of low-cost magnetic rail designs by integrating ferrite magnets and NdFeB magnets for HTS Maglev systems

Science.gov (United States)

Sun, R. X.; Deng, Z. G.; Gou, Y. F.; Li, Y. J.; Zheng, J.; Wang, S. Y.; Wang, J. S.

2015-09-01

Permanent magnet guideway (PMG) is an indispensable part of high temperature superconducting (HTS) Maglev systems. Present PMGs are made of NdFeB magnets with excellent performance and cost much. As another permanent magnet material, the ferrite magnet is weak at magnetic energy product and coercive force, but inexpensive. So, it is a possible way to integrate the ferrite and NdFeB magnets for cutting down the cost of present PMGs. In the paper, the equivalent on magnetic field intensity between ferrite magnets and NdFeB magnets was evaluated by finite element simulation. According to the calculation results, the magnetic field of the PMG integrating ferrite magnets and NdFeB magnets can be increased remarkably comparing with the pure ferrite PMG. It indicates that low-cost PMG designs by integrating the two permanent magnet materials are feasible for the practical HTS Maglev system.

ESCAR superconducting magnet system

International Nuclear Information System (INIS)

Gilbert, W.S.; Meuser, R.B.; Pope, W.L.; Green, M.A.

1975-01-01

Twenty-four superconducting dipoles, each about 1 meter long, provide the guide field for the Experimental Superconducting Accelerator Ring proton accelerator--storage ring. Injection of 50 MeV protons corresponds to a 3 kG central dipole field, and a peak proton energy of 4.2 GeV corresponds to a 46 kG central field. Thirty-two quadrupoles provide focusing. The 56 superconducting magnets are contained in 40 cryostats that are cryogenically connected in a novel series ''weir'' arrangement. A single 1500 W refrigeration plant is required. Design and testing of the magnet and cryostat system are described. (U.S.)

Globally optimal, minimum stored energy, double-doughnut superconducting magnets.

Science.gov (United States)

Tieng, Quang M; Vegh, Viktor; Brereton, Ian M

2010-01-01

The use of the minimum stored energy current density map-based methodology of designing closed-bore symmetric superconducting magnets was described recently. The technique is further developed to cater for the design of interventional-type MRI systems, and in particular open symmetric magnets of the double-doughnut configuration. This extends the work to multiple magnet domain configurations. The use of double-doughnut magnets in MRI scanners has previously been hindered by the ability to deliver strong magnetic fields over a sufficiently large volume appropriate for imaging, essentially limiting spatial resolution, signal-to-noise ratio, and field of view. The requirement of dedicated interventional space restricts the manner in which the coils can be arranged and placed. The minimum stored energy optimal coil arrangement ensures that the field strength is maximized over a specific region of imaging. The design method yields open, dual-domain magnets capable of delivering greater field strengths than those used prior to this work, and at the same time it provides an increase in the field-of-view volume. Simulation results are provided for 1-T double-doughnut magnets with at least a 50-cm 1-ppm (parts per million) field of view and 0.7-m gap between the two doughnuts. Copyright (c) 2009 Wiley-Liss, Inc.

A current controlled matrix converter for wind energy conversion systems based on permanent magnet synchronous generator

Directory of Open Access Journals (Sweden)

Naggar H. Saad

2016-05-01

Full Text Available The main challenges of wind energy conversion systems (WECS are to maximize the energy capture from the wind and injecting reactive power during the fault. This paper presents a current controlled matrix converter to interface Permanent Magnet Synchronous Generators (PMSG based WECS with the grid. To achieve fast dynamic response with reduced current ripples, a hysteresis current control is utilized. The proposed control system decouples the active and reactive components of the PMSG current to extract the maximum power from the wind at a given wind velocity and to inject reactive power to the grid. Reactive power injection during the fault satisfying the grid-codes requirement. The proposed WECS has been modeled and simulated using PSCAD/EMTDC software package.

Magnetic fusion energy technology fellowship: Report on survey of institutional coordinators

International Nuclear Information System (INIS)

1993-02-01

In 1980, the Magnetic Fusion Energy Technology (MFET) Fellowship program was established by the US Department of Energy, Office of Fusion Energy, to encourage outstanding students interested in fusion energy technology to continue their education at a qualified graduate school. The basic objective of the MFET Fellowship program is to ensure an adequate supply of scientists in this field by supporting graduate study, training, and research in magnetic fusion energy technology. The program also supports the broader objective of advancing fusion toward the realization of commercially viable energy systems through the research by MFET fellows. The MFET Fellowship program is administered by the Science/Engineering Education Division of Oak Ridge Institute for Science and Education. Guidance for program administration is provided by an academic advisory committee

Spin and energy transfer between magnetic ions and free carriers in diluted-magnetic semiconductor heterostructures

Energy Technology Data Exchange (ETDEWEB)

Yakovlev, D.R. [Experimental Physics 2, University of Dortmund, 44227 Dortmund (Germany); Ioffe Physico-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation); Kneip, M.; Bayer, M. [Experimental Physics 2, University of Dortmund, 44227 Dortmund (Germany); Maksimov, A.A.; Tartakovskii, I.I. [Institute of Solid State Physics, Russian Academy of Sciences, 142432 Chernogolovka (Russian Federation); Keller, D.; Ossau, W.; Molenkamp, L.W. [Physikalisches Institut der Universitaet Wuerzburg, 97074 Wuerzburg (Germany); Scherbakov, A.V.; Akimov, A.V. [Ioffe Physico-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation); Waag, A. [Abteilung Halbleiterphysik, Universitaet Ulm, 89081 Ulm (Germany)

2004-03-01

In this paper we give a brief overview of our studies on dynamical processes in diluted-magnetic-semiconductor heterostructures based on (Zn,Mn)Se and (Cd,Mn)Te. Presence of free carriers is an important factor which determines the energy- and spin transfer in a coupled systems of magnetic ions, lattice (the phonon system) and carriers. We report also new data on dynamical response of magnetic ions interacting with photogenerated electron-hole plasma. (Zn,Mn)Se/(Zn,Be)Se structures with relatively high Mn content of 11% provide spin-lattice relaxation time of about 20 ns, which is considerably shorter then the characteristic times of nonequilibrium phonons ranging to 1 {mu}s. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Overview of the Magnetic Fusion Energy Devlopment and Technology Program

International Nuclear Information System (INIS)

1978-03-01

This publication gives a comprehensive introduction to controlled fusion research. Topics covered in the discussion include the following: (1) fusion system engineering and advanced design, (2) plasma engineering, (3) magnetic systems, (4) materials, (5) environment and safety, and (6) alternate energy applications

Overview of the US Magnetic Fusion Energy Program

International Nuclear Information System (INIS)

Wiffen, F.W.; Dowling, R.J.; Marton, W.A.; Eckstrand, S.A.

1990-01-01

Since the 1988 Symposium on Fusion Technology, steady progress has been made in the US Magnetic Fusion Energy Program. The large US tokamaks have reached new levels of plasma performance with associated improvements in the understanding of transport. The technology support for ongoing and future devices is similarly advancing with notable advances in magnetic, rf heating tubes, pellet injector, plasma interactive materials, tritium handling, structural materials, and system studies. Currently, a high level DOE review of the program is underway to provide recommendations for a strategic plan

Superconducting magnetic energy storage and superconducting self-supplied electromagnetic launcher

Science.gov (United States)

Ciceron, Jérémie; Badel, Arnaud; Tixador, Pascal

2017-10-01

Superconductors can be used to build energy storage systems called Superconducting Magnetic Energy Storage (SMES), which are promising as inductive pulse power source and suitable for powering electromagnetic launchers. The second generation of high critical temperature superconductors is called coated conductors or REBCO (Rare Earth Barium Copper Oxide) tapes. Their current carrying capability in high magnetic field and their thermal stability are expanding the SMES application field. The BOSSE (Bobine Supraconductrice pour le Stockage d'Energie) project aims to develop and to master the use of these superconducting tapes through two prototypes. The first one is a SMES with high energy density. Thanks to the performances of REBCO tapes, the volume energy and specific energy of existing SMES systems can be surpassed. A study has been undertaken to make the best use of the REBCO tapes and to determine the most adapted topology in order to reach our objective, which is to beat the world record of mass energy density for a superconducting coil. This objective is conflicting with the classical strategies of superconducting coil protection. A different protection approach is proposed. The second prototype of the BOSSE project is a small-scale demonstrator of a Superconducting Self-Supplied Electromagnetic Launcher (S3EL), in which a SMES is integrated around the launcher which benefits from the generated magnetic field to increase the thrust applied to the projectile. The S3EL principle and its design are presented. Contribution to the topical issue "Electrical Engineering Symposium (SGE 2016)", edited by Adel Razek

Test equipment for a flywheel energy storage system using a magnetic bearing composed of superconducting coils and superconducting bulks

International Nuclear Information System (INIS)

Ogata, M; Matsue, H; Yamashita, T; Hasegawa, H; Nagashima, K; Maeda, T; Matsuoka, T; Mukoyama, S; Shimizu, H; Horiuchi, S

2016-01-01

Energy storage systems are necessary for renewable energy sources such as solar power in order to stabilize their output power, which fluctuates widely depending on the weather. Since ‘flywheel energy storage systems’ (FWSSs) do not use chemical reactions, they do not deteriorate due to charge or discharge. This is an advantage of FWSSs in applications for renewable energy plants. A conventional FWSS has capacity limitation because of the mechanical bearings used to support the flywheel. Therefore, we have designed a superconducting magnetic bearing composed of a superconducting coil stator and a superconducting bulk rotor in order to solve this problem, and have experimentally manufactured a large scale FWSS with a capacity of 100 kWh and an output power of 300 kW. The superconducting magnetic bearing can levitate 4 tons and enables the flywheel to rotate smoothly. A performance confirmation test will be started soon. An overview of the superconducting FWSS is presented in this paper. (paper)

Energy buildup in sheared force-free magnetic fields

Science.gov (United States)

Wolfson, Richard; Low, Boon C.

1992-01-01

Photospheric displacement of the footpoints of solar magnetic field lines results in shearing and twisting of the field, and consequently in the buildup of electric currents and magnetic free energy in the corona. The sudden release of this free energy may be the origin of eruptive events like coronal mass ejections, prominence eruptions, and flares. An important question is whether such an energy release may be accompanied by the opening of magnetic field lines that were previously closed, for such open field lines can provide a route for matter frozen into the field to escape the sun altogether. This paper presents the results of numerical calculations showing that opening of the magnetic field is permitted energetically, in that it is possible to build up more free energy in a sheared, closed, force-free magnetic field than is in a related magnetic configuration having both closed and open field lines. Whether or not the closed force-free field attains enough energy to become partially open depends on the form of the shear profile; the results presented compare the energy buildup for different shear profiles. Implications for solar activity are discussed briefly.

Design of a magnetic field alignment diagnostic for the MFTF-B magnet system

International Nuclear Information System (INIS)

Deadrick, F.J.; House, P.A.; Frye, R.W.

1985-01-01

Magnet alignment in tandem mirror fusion machines plays a crucial role in achieving and maintaining plasma confinement. Various visual alignment tools have been described by Post et al. to align the Tara magnet system. We have designed and installed a remotely operated magnetic field alignment (MFA) diagnostic system as a part of the Mirror Fusion Test Facility (MFTF-B). It measures critical magnetic field alignment parameters of the MFTF-B coil set while under full-field operating conditions. The MFA diagnostic employs a pair of low-energy, electron beam guns on a remotely positionable probe to trace and map selected magnetic field lines. An array of precision electrical detector paddles locates the position of the electron beam, and thus the magnetic field line, at several critical points. The measurements provide a means to compute proper compensating currents to correct for mechanical misalignments of the magnets with auxiliary trim coils if necessary. This paper describes both the mechanical and electrical design of the MFA diagnostic hardware

Magnetic energy density and plasma energy density in the Venus wake

Science.gov (United States)

Perez De Tejada, H. A.; Durand-Manterola, H. J.; Lundin, R.; Barabash, S.; Zhang, T.; Reyes-Ruiz, M.; Sauvaud, J.

2013-05-01

Magnetic energy density and plasma energy density in the Venus wake H. Pérez-de-Tejada1, H. Durand-Manterola1, R. Lundin2, S. Barabash2, T. L. Zhang3, A. Sauvaud4, M. Reyes-Ruiz5. 1 - Institute of Geophysics, UNAM, México, D. F. 2 - Swedish Institute of Space Physics, Umea, Sweden 3 - Space Research Institute, Graz, Austria 4 - CESR, Toulouse, France 5 - Institute of Astronomy, UNAM, Ensenada, México Measurements conducted in the Venus wake with the magnetometer and the Aspera-4 plasma instrument of the Venus Express spacecraft show that average values of the kinetic energy density of the plasma in that region are comparable to average local values of the magnetic energy density. Observations were carried out in several orbits of the Venus Express near the midnight plane and suggest that the total energy content in the Venus wake is distributed with nearly comparable values between the plasma and the magnetic field. Processes associated with the solar wind erosion of planetary ions from the polar magnetic regions of the ionosphere are involved in the comparable distribution of both energy components.

Novel ocean energy permanent magnet linear generator buoy

Energy Technology Data Exchange (ETDEWEB)

Rhinefrank, K.; Agamloh, E.B.; Jouanne, A. von; Wallace, A.K.; Prudell, J.; Kimble, K.; Aills, J.; Schmidt, E.; Schacher, A. [School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR 97331-3211 (United States); Chan, P.; Sweeny, B. [Department of Mechanical Engineering, Oregon State University, Corvallis, OR 97331-3211 (United States)

2006-07-15

This paper describes the research, design, construction and prototype testing process of a novel ocean energy direct drive permanent magnet linear generator buoy. The buoy employs the vertical component of the motion of ocean waves to power a linear generator. The generator consists of a permanent magnet field system (mounted on the central translator shaft) and an armature, in which the power is generated (mounted on the buoy). The translator shaft is anchored to the sea floor, and the buoy/floater moves armature coils relative to the permanent magnet translator to induce voltages. The electrical and mechanical structures of the buoy generator are provided, along with performance characteristics, including voltage, current and developed power. (author)

High Tc superconducting energy storage systems

Energy Technology Data Exchange (ETDEWEB)

Werfel, Frank [Adelwitz Technologiezentrum GmbH (ATZ), Arzberg-Adelwitz (Germany)

2012-07-01

Electric energy is basic to heat and light our homes, to power our businesses and to transport people and goods. Powerful storage techniques like SMES, Flywheel, Super Capacitor, and Redox - Flow batteries are needed to increase the overall efficiency, stability and quality of electrical grids. High-Tc superconductors (HTS) possess superior physical and technical properties and can contribute in reducing the dissipation and losses in electric machines as motors and generators, in electric grids and transportation. The renewable energy sources as solar, wind energy and biomass will require energy storage systems even more as a key technology. We survey the physics and the technology status of superconducting flywheel energy storage (FESS) and magnetic energy storage systems (SMES) for their potential of large-scale commercialization. We report about a 10 kWh / 250 kW flywheel with magnetic stabilization of the rotor. The progress of HTS conductor science and technological engineering are basic for larger SMES developments. The performance of superconducting storage systems is reviewed and compared. We conclude that a broad range of intensive research and development in energy storage is urgently needed to produce technological options that can allow both climate stabilization and economic development.

Technical-economic analysis of electric energy storage systems

International Nuclear Information System (INIS)

Stefanescu, Florian; Curuia, Marian; Brad, Sebastian; Anghel, Mihai; Stefanescu, Ioan

2009-01-01

Fluctuations in electric energy consumption and changes that affected last years the electric energy market, as well, entail perturbations in transport and distribution systems due to outrunning of their current physical capacities. Consequently, storing the electric energy in buffer systems appears to be a must owing to its strategic and economical importance. Indeed, it can enhance firmly the capacity of fulfilling the electric energy demands in real time and so, avoiding the blackout events caused by disruptions in power supply . Also, of great importance is the role of energy storing systems as backing ancillaries for promoting variable or uncertain renewable sources (like photovoltaic or wind sources). The Superconducting Magnetic Energy Storage (SMES) is a promising system of direct storing of electricity by means of magnetic energy deposing in a short-circuited superconducting loop. However difficulties related to the use o superconducting systems and cryogenic temperatures (concerning construction and maintenance) hinder at present the application of SMES systems on a scale larger than some particular applications. Actually, owing to the lack of alternative solutions the rather high costs are accepted in such cases

Superconducting magnetic energy storage (SMES). Results of a technology assessment

International Nuclear Information System (INIS)

Fleischer, T.; Juengst, K.P.; Brandl, V.; Maurer, W.; Nieke, E.

1995-05-01

The authors report on results of a Technology Assessment study commissioned by the German Federal Ministry of Education, Science, Research and Technology. The objective of this study was to evaluate the potential of superconducting magnetic energy storage (SMES) technology with respect to the economical, political and organization structures in the Federal Republic of Germany. The main focus of the study was on the technical and economic potential of large-scale SMES for diurnal load levelling applications. It was shown that there is no demand for the development of large SMES in Germany in the short and medium term. A second range of applications investigated is storage of electric energy for immediate delivery or consumption of electric power in case of need or for periodic power supply within the range of seconds. Due to its excellent dynamic properties SMES has substantial advantages over conventional storage technologies in this field. For those so-called dynamic applications SMES of small and medium energy capacity are needed. It was shown that SMES may be economically attractive for the provision of spinning reserve capacity in electrical networks, in particular cases for power quality applications (uninterruptable power supply, UPS) and for the compensation of cyclic loads, as well as in some market niches. The use of SMES for storage of recuperated energy in electrical railway traction systems has been proven to be uneconomical. Mobile SMES applications are unrealistic due to technical and size limitations. In SMES systems the energy is stored in a magnetic field. Biological objects as well as technical systems in the vicinity of a SMES plant are exposed to this field. The knowledge on impacts of magnetic fields on sensitive technical systems as well as on living organisms and especially on effects on human health is rather small and quite uncertain. (orig./MM) [de

Adaptive automatic generation control with superconducting magnetic energy storage in power systems

International Nuclear Information System (INIS)

Tripathy, S.C.; Balasubramanian, R.; Nair, P.S.C.

1992-01-01

An improved automatic generation control (AGC) employing self-tuning adaptive control for both main AGC loop and superconducting magnetic energy storage (SMES) is presented in this paper. Computer simulations on a two-area interconnected power system show that the proposed adaptive control scheme is very effective in damping out oscillations caused by load disturbances and its performance is quite insensitive to controller gain parameter changes of SMES. A comprehensive comparative performance evaluation of control schemes using adaptive and non-adaptive controllers in the main AGC and in the SMES control loops is presented. The improvement in performance brought in by the adaptive scheme is particularly pronounced for load changes of random magnitude and duration. The proposed controller can be easily implemented using microprocessors

Sensorless magnetically levitated system with reduced observer

Energy Technology Data Exchange (ETDEWEB)

Friedrich, T [Inst. fuer Elektrische Maschinen, RWTH Aachen (Germany); Henneberger, G [Inst. fuer Elektrische Maschinen, RWTH Aachen (Germany); Ress, C [Inst. fuer Elektrische Maschinen, RWTH Aachen (Germany)

1996-12-31

The present paper describes the use of a reduced observer for a hybrid excited magnetic levitation system. The latter is part of a contactless and energy saving driven conveyance system. Thereby one has to select the working point of the system in such a way, that the force due to the weight of the vehicle including its load will be compensated only by the permanent magnets. The linearized model is observable even if only the current in the coils is measured. Therefore it seems reasonable to evaluate the other variables of the state vector by an observer. Thus the sensors for the airgap can be omitted. Using an observer has another advantage as well. It will tune the airgap automatically to the value which is necessary in order to operate the system in the most energy saving way. The whole design was simulated. (orig.)

A high pulsed power supply system designed for pulsed high magnetic field

International Nuclear Information System (INIS)

Liu Kefu; Wang Shaorong; Zhong Heqing; Xu Yan; Pan Yuan

2008-01-01

This paper introduces the design of high pulsed power supply system for producing pulsed high magnetic field up to 70 T. This system consists of 58 sets of 55 μF of capacitor bank which provides 1.0 MJ energy storage. A set of vacuum closing switch is chosen as main switch for energy discharge into magnetic coil. A crowbar circuit with high power diodes in series with resistor is used to absorb the redundant energy and adjust pulse width. The resistance of magnetic coil changing with current is deduced by energy balance equations. A capacitor-charging power supply using a series-resonant, constant on-time variable frequency control, and zero-current switching charges the capacitor bank in one minute time with high efficiency. The pulsed power supply provides adjustable current and pulse width with 30 kA peak and 30 ms maximum. The primary experiments demonstrate the system reliability. This work provides an engineering guidance for future development of pulsed high magnetic field. (authors)

Axicell MFTF-B superconducting-magnet system

International Nuclear Information System (INIS)

Wang, S.T.; Bulmer, R.; Hanson, C.; Hinkle, R.; Kozman, T.; Shimer, D.; Tatro, R.; VanSant, J.; Wohlwend, J.

1982-01-01

The Axicell MFTF-B magnet system will provide the field environment necessary for tandem mirror plasma physics investigation with thermal barriers. The performance of the device will stimulate DT to achieve energy break-even plasma conditions. Operation will be with deuterium only. There will be 24 superconducting coils consisting of 2 sets of yin-yang pairs, 14 central-cell solenoids, 2 sets of axicell mirror-coil pairs, and 2 transition coils between the axicell mirror coil-pairs and the yin-yang coils. This paper describes the progress in the design and construction of MFTF-B Superconducting-Magnet System

A quench detection/logging system for the SSCL Magnet Test Laboratory

International Nuclear Information System (INIS)

Kim, K.; Coles, M.; Dryer, J.; Lambert, D.

1993-05-01

The quench in a magnet describes a process which occurs while the superconductivity state goes to the normal resistive state. The consequence of a quench is the conversion of the stored electromagnetic energy into heat. During this process the initiating point will reach a high temperature, which will char the insulation or melt the conductor and thereby destroy the magnet. To prevent the magnet from being lost, it is standard practice to observe several resistance and/or inductance voltages across the magnet as quench signatures -- detection. When a quench symptom is detected, protection operations are initiated: proper shutdown of the magnet excitation systems and treatment to dilute the heat energy at a spot -- protection. The temperature rise is diluted by firing heaters along the length of the magnet to insure that the dissipated energy is spread. To develop a reliable quench detection system, two distinct approaches have been tried in the past: (i) Understanding of the Noise Mechanism and Sub-system Optimization, and (ii) Escaping from the Known Electromagnetic Noises by Observing Optical Waves or Acoustic Waves. The MTL of SSCL confronts a mass-measurement of about 10,000 production magnets. To meet the testing schedule, the false quench detection rate needs to be further optimized while the true quench detection rate remains secure for the magnet measurement safety. To meet these requirements, we followed an iterative top-down approach. First we defined the signal and noise characteristics of the quench phenomena by using existing software tools to build a rapid prototype system incorporating all proven functionality of the existing system. Then we further optimize the system through iterative upgrading based on our signal and noise character findings

Enhanced Energy Density in Permanent Magnets using Controlled High Magnetic Field during Processing

Energy Technology Data Exchange (ETDEWEB)

Carter, William G [ORNL; Rios, Orlando [ORNL; Constantinides, Steven [ORNL

2016-05-05

This ORNL Manufacturing Demonstraction Facility (MDF) technical collaboration focused on the use of high magnetic field processing (>2Tesla) using energy efficient large bore superconducting magnet technology and high frequency electromagnetics to improve magnet performance and reduce the energy budget associated with Alnico thermal processing. Alnico, alloys containing Al, Ni, Co and Fe, represent a class of functional nanostructured alloys, and show the greatest potential for supplementing or replacing commercial Nd-based rare-earth alloy magnets.

Magnetic field dependence of vortex activation energy

Indian Academy of Sciences (India)

... the resistance as a function of temperature and magnetic field in clean polycrystalline samples of NbSe2, MgB2 and Bi2Sr2Ca2Cu3O10 (BSCCO) superconductors. Thermally activated flux flow behaviour is seen in all the three systems and clearly identified in bulk MgB2. While the activation energy at low fields for MgB2 ...

The Limit of Free Magnetic Energy in Active Regions

Science.gov (United States)

Moore, Ron; Falconer, David; Sterling, Alphonse

2012-01-01

By measuring from active-region magnetograms a proxy of the free energy in the active region fs magnetic field, it has been found previously that (1) there is an abrupt upper limit to the free energy the field can hold that increases with the amount of magnetic field in the active region, the active region fs magnetic flux content, and (2) the free energy is usually near its limit when the field explodes in a CME/flare eruption. That is, explosive active regions are concentrated in a main-sequence path bordering the free-energy ]limit line in (flux content, free-energy proxy) phase space. Here, from measurement of Marshall Space Flight Center vector magnetograms, we find the magnetic condition that underlies the free ]energy limit and the accompanying main sequence of explosive active regions. Using a suitable free ]energy proxy measured from vector magnetograms of 44 active regions, we find that (1) in active regions at and near their free ]energy limit, the ratio of magnetic-shear free energy to the non ]free magnetic energy the potential field would have is approximately 1 in the core field, the field rooted along the neutral line, and (2) this ratio is progressively less in active regions progressively farther below their free ]energy limit. This shows that most active regions in which this core-field energy ratio is much less than 1 cannot be triggered to explode; as this ratio approaches 1, most active regions become capable of exploding; and when this ratio is 1 or greater, most active regions are compelled to explode. From these results we surmise the magnetic condition that determines the free ]energy limit is the ratio of the free magnetic energy to the non-free energy the active region fs field would have were it completely relaxed to its potential ]field configuration, and that this ratio is approximately 1 at the free-energy limit and in the main sequence of explosive active regions.

Simulation of a resonant-type ring magnet power supply with multiple resonant cells and energy storage chokes

International Nuclear Information System (INIS)

Kim, J.M.S.; Blackmore, E.W.; Reiniger, K.W.

1992-01-01

For the TRIUMF KAON Factory Booster Ring, a resonant-type magnet power supply has been proposed for the dipole magnet excitation. The Booster Ring magnet power supply system based on resonant circuits, coupled with distributed energy make-up networks, is a complex system, sensitive to many system parameters. When multiple resonant cells, each with its own energy make-up network, are connected in a ring, it is very difficult to derive closed-form solutions to determine the operating conditions of the power supply system. A meaningful way to understand and analyze such a complex system is to use a simulation tool. This paper presents the analysis of operating conditions of the resonant-type ring magnet power supply with multiple resonant cells, using the circuit simulation tool, SPICE. The focus of the study is on the effect of circuit parameter variations in energy storage chokes

The Magnetic Free Energy in Active Regions

Science.gov (United States)

Metcalf, Thomas R.; Mickey, Donald L.; LaBonte, Barry J.

2001-01-01

The magnetic field permeating the solar atmosphere governs much of the structure, morphology, brightness, and dynamics observed on the Sun. The magnetic field, especially in active regions, is thought to provide the power for energetic events in the solar corona, such as solar flares and Coronal Mass Ejections (CME) and is believed to energize the hot coronal plasma seen in extreme ultraviolet or X-rays. The question remains what specific aspect of the magnetic flux governs the observed variability. To directly understand the role of the magnetic field in energizing the solar corona, it is necessary to measure the free magnetic energy available in active regions. The grant now expiring has demonstrated a new and valuable technique for observing the magnetic free energy in active regions as a function of time.

Globally optimal superconducting magnets part I: minimum stored energy (MSE) current density map.

Science.gov (United States)

Tieng, Quang M; Vegh, Viktor; Brereton, Ian M

2009-01-01

An optimal current density map is crucial in magnet design to provide the initial values within search spaces in an optimization process for determining the final coil arrangement of the magnet. A strategy for obtaining globally optimal current density maps for the purpose of designing magnets with coaxial cylindrical coils in which the stored energy is minimized within a constrained domain is outlined. The current density maps obtained utilising the proposed method suggests that peak current densities occur around the perimeter of the magnet domain, where the adjacent peaks have alternating current directions for the most compact designs. As the dimensions of the domain are increased, the current density maps yield traditional magnet designs of positive current alone. These unique current density maps are obtained by minimizing the stored magnetic energy cost function and therefore suggest magnet coil designs of minimal system energy. Current density maps are provided for a number of different domain arrangements to illustrate the flexibility of the method and the quality of the achievable designs.

Lamination and end pack design studies of SSC low energy booster magnet prototypes

International Nuclear Information System (INIS)

Li, N.

1993-05-01

The SSC Laboratory plans to deploy two ''large'' detectors for the essential high-energy physics experiments at the initial startup of the collider. The GEM detector is optimized to emphasize precise measurement of photons and electrons, as well as precise tracking of high-energy muons. An essential part of the GEM detector is the magnet subsystem, which provides the magnetic field necessary for identification and high-resolution tracking of charged particles. This large superconducting magnet system, with ferromagnetic field-shapers, presents a variety of engineering challenges in superconductor technology, in magnet-winding technology, fabrication, assembly and installation of large and heavy components, and in ensuring the required high operating availability

High energy magnetic excitations

International Nuclear Information System (INIS)

Endoh, Yasuo

1988-01-01

The report emphasizes that the current development in condensed matter physics opens a research field fit to inelastic neutron scattering experiments in the eV range which is easilly accessed by spallation neutron sources. Several important subjects adopted at thermal reactors are shown. It is desired to extend the implementation of the spectroscopic experiments for investigation of higher energy magnetic excitations. For La 2 CuO 4 , which is the mother crystal of the first high Tc materials found by Bednortz and Muller, it seems to be believed that the magnetism is well characterized by the two-dimensional Heisenberg antiferromagnetic Hamiltonian, and it is widely accepted that the magnetism is a most probable progenitor of high Tc superconductors. The unusual properties of spin correlations in this crystal have been studied extensively by standard neutron scattering techniques with steady neutrons at BNL. FeSi is not ordered magnetically but shows a very unique feature of temperature induced magnetism, which also has been studied extensively by using the thermal neutron scattering technique at BNL. In these experiments, polarized neutrons are indispensable to extract the clean magnetic components out of other components of non-magnetic scattering. (N.K.)

A magnet system for HEP experiments

CERN Document Server

Gaddi, A

2012-01-01

This chapter describes the sequence of steps that lead to the design of a magnet system for modern HEP detectors. We start looking to the main types of magnets used in HEP experiments, along with some basic formulae to set the main parameters, such as ampere-turns, impedance and stored energy. A section is dedicated to the description of the iron yoke, with emphasis on magnet-detector integration and assembly, steel characteristics, stray field issues and alternative design. In the second part of the chapter we start looking at a brief history of superconducting magnets and a comparison between warm and superconducting ones. Following that, we describe the commonly used superconducting cables, the conductor design and technology and the winding techniques. A section of the chapter is dedicated to the cryogenic design, vacuum insulation and other ancillary systems. We also describe the power circuit, with the power supply unit, the current leads, the current measurement devices and other instruments and safety...

A quench detection/logging system for the SSCL Magnet Test Laboratory

International Nuclear Information System (INIS)

Kim, K.; Coles, M.; Dryer, J.; Lambert, D.

1994-01-01

The quench in a magnet describes a process which occurs while the superconductivity state goes to the normal resistive state. The consequence of a quench is the conversion of the stored electromagnetic energy into heat. During this process the initiating point will reach a high temperature, which will char the insulation or melt the conductor and thereby destroy the magnet. To prevent the magnet from being lost, it is standard practice to observe several resistance and/or inductance voltages across the magnet as quench signatures - Detection. When a quench symptom is detected, protection operations are initiated: proper shutdown of the magnet excitation systems and treatment to dilute the heat energy at a spot - Protection. The temperature rise is diluted by firing heaters along the length of the magnet to ensure that the dissipated energy is spread. It is interesting that there is not a significant amount of published research on detection. To afford a more reliable quench detection system, two distinct approaches have been tried in the past: (i) Understanding of the Noise Mechanism and Sub-system Optimization, and (ii) Escaping from the Known Electromagnetic Noises by Observing Optical Waves or Acoustic Waves. The MTL of SSCL confronts a mass-measurement of about 10,000 production magnets. To meet the testing schedule, the false quench detection rate needs to be further optimized while the true quench detection rate remains secure for the magnet measurement safety. To meet these requirements, the authors followed an iterative top-down approach. First they defend the signal and noise characteristics of the quench phenomena by using existing software tools to build a rapid prototype system incorporating all proven functionality of the existing system. Then they further optimize the system through iterative upgrading based on their signal and noise character findings

Towards a Decentralized Magnetic Indoor Positioning System

Science.gov (United States)

Kasmi, Zakaria; Norrdine, Abdelmoumen; Blankenbach, Jörg

2015-01-01

Decentralized magnetic indoor localization is a sophisticated method for processing sampled magnetic data directly on a mobile station (MS), thereby decreasing or even avoiding the need for communication with the base station. In contrast to central-oriented positioning systems, which transmit raw data to a base station, decentralized indoor localization pushes application-level knowledge into the MS. A decentralized position solution has thus a strong feasibility to increase energy efficiency and to prolong the lifetime of the MS. In this article, we present a complete architecture and an implementation for a decentralized positioning system. Furthermore, we introduce a technique for the synchronization of the observed magnetic field on the MS with the artificially-generated magnetic field from the coils. Based on real-time clocks (RTCs) and a preemptive operating system, this method allows a stand-alone control of the coils and a proper assignment of the measured magnetic fields on the MS. A stand-alone control and synchronization of the coils and the MS have an exceptional potential to implement a positioning system without the need for wired or wireless communication and enable a deployment of applications for rescue scenarios, like localization of miners or firefighters. PMID:26690145

Towards a Decentralized Magnetic Indoor Positioning System

Directory of Open Access Journals (Sweden)

Zakaria Kasmi

2015-12-01

Full Text Available Decentralized magnetic indoor localization is a sophisticated method for processing sampled magnetic data directly on a mobile station (MS, thereby decreasing or even avoiding the need for communication with the base station. In contrast to central-oriented positioning systems, which transmit raw data to a base station, decentralized indoor localization pushes application-level knowledge into the MS. A decentralized position solution has thus a strong feasibility to increase energy efficiency and to prolong the lifetime of the MS. In this article, we present a complete architecture and an implementation for a decentralized positioning system. Furthermore, we introduce a technique for the synchronization of the observed magnetic field on the MS with the artificially-generated magnetic field from the coils. Based on real-time clocks (RTCs and a preemptive operating system, this method allows a stand-alone control of the coils and a proper assignment of the measured magnetic fields on the MS. A stand-alone control and synchronization of the coils and the MS have an exceptional potential to implement a positioning system without the need for wired or wireless communication and enable a deployment of applications for rescue scenarios, like localization of miners or firefighters.

ATLAS magnet common cryogenic, vacuum, electrical and control systems

CERN Document Server

Miele, P; Delruelle, N; Geich-Gimbel, C; Haug, F; Olesen, G; Pengo, R; Sbrissa, E; Tyrvainen, H; ten Kate, H H J

2004-01-01

The superconducting Magnet System for the ATLAS detector at the LHC at CERN comprises a Barrel Toroid, two End Cap Toroids and a Central Solenoid with overall dimensions of 20 m diameter by 26 m length and a stored energy of 1.6 GJ. Common proximity cryogenic and electrical systems for the toroids are implemented. The Cryogenic System provides the cooling power for the 3 toroid magnets considered as a single cold mass (600 tons) and for the CS. The 21 kA toroid and the 8 kA solenoid electrical circuits comprise both a switch-mode power supply, two circuit breakers, water cooled bus bars, He cooled current leads and the diode resistor ramp-down unit. The Vacuum System consists of a group of primary rotary pumps and sets of high vacuum diffusion pumps connected to each individual cryostat. The Magnet Safety System guarantees the magnet protection and human safety through slow and fast dump treatment. The Magnet Control System ensures control, regulation and monitoring of the operation of the magnets. The update...

Magnetic-Field-Response Measurement-Acquisition System

Science.gov (United States)

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

2006-01-01

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

Oscillations of the energy, magnetic moment, and current with a period equal to the normal or superconducting flux quantum in cyclic systems

International Nuclear Information System (INIS)

Svirskii, M.S.

1985-01-01

Oscillations with a period equal to the normal or superconducting flux quantum occur in the current density and the orbital parts of the energy and the magnetic moment in cyclic systems. Transitions between these regimes can be induced by changing the number of electrons or by switching between states with different energies

Symmetric Double Quantum Dot Energy States in a High Magnetic Field

International Nuclear Information System (INIS)

Morgenstern Horing, Norman J; Sawamura, Makoto

2011-01-01

The dynamical Green's function and energy spectrum of a 2D symmetric quantum double-dot system on a planar host in a normal magnetic field are analyzed here, representing the two dots by Dirac delta function potentials. The proliferation of energy levels due to Landau quantization is examined in detail.

Phase-dependent dynamic potential of magnetically coupled two-degree-of-freedom bistable energy harvester.

Science.gov (United States)

Kim, Pilkee; Nguyen, Minh Sang; Kwon, Ojin; Kim, Young-Jin; Yoon, Yong-Jin

2016-09-28

A system of magnetically coupled oscillators has been recently considered as a promising compact structure to integrate multiple bistable energy harvesters (BEHs), but its design is not straightforward owing to its varying potential energy pattern, which has not been understood completely yet. This study introduces the concept of phase-dependent dynamic potential in a magnetically coupled BEH system with two degrees of freedom (DOFs) to explain the underlying principle of the complicated dynamics of the system. Through theoretical simulations and analyses, two distinct dynamic regimes, called the out-of-phase and in-phase mode regimes in this report, are found to exist in the frequency regions of the 1 st and 2 nd primary intrawell resonances. For the out-of-phase mode regime, the frequency displacement (and output power) responses of the 2-DOF BEH system exhibit typical double-well dynamics, whereas for the in-phase mode regime, only single-well dynamics is observed though the system is statically bistable. These dynamic regimes are also revealed to be caused by the difference in the dynamic potential energy trajectories propagating on a high-dimensional potential energy surface. The present approach to the dynamics of the 2-DOF BEH system can be extended and applied to higher-DOF systems, which sheds light on compact and efficient designs of magnetically coupled BEH chain structures.

Magnetically coupled flextensional transducer for wideband vibration energy harvesting: Design, modeling and experiments

Science.gov (United States)

Zou, Hong-Xiang; Zhang, Wen-Ming; Li, Wen-Bo; Wei, Ke-Xiang; Hu, Kai-Ming; Peng, Zhi-Ke; Meng, Guang

2018-03-01

The combination of nonlinear bistable and flextensional mechanisms has the advantages of wide operating frequency and high equivalent piezoelectric constant. In this paper, three magnetically coupled flextensional vibration energy harvesters (MF-VEHs) are designed from three magnetically coupled vibration systems which utilize a magnetic repulsion, two symmetrical magnetic attractions and multi-magnetic repulsions, respectively. The coupled dynamic models are developed to describe the electromechanical transitions. Simulations under harmonic excitation and random excitation are carried out to investigate the performance of the MF-VEHs with different parameters. Experimental validations of the MF-VEHs are performed under different excitation levels. The experimental results verify that the developed mathematical models can be used to accurately characterize the MF-VEHs for various magnetic coupling modes. A comparison of three MF-VEHs is provided and the results illustrate that a reasonable arrangement of multiple magnets can reduce the threshold excitation intensity and increase the harvested energy.

Energy-based ferromagnetic material model with magnetic anisotropy

Energy Technology Data Exchange (ETDEWEB)

Steentjes, Simon, E-mail: simon.steentjes@iem.rwth-aachen.de [Institute of Electrical Machines - RWTH Aachen University, Schinkelstr. 4, D-52056 Aachen (Germany); Henrotte, François, E-mail: francois.henrotte@uclouvain.be [Institute of Mechanics Materials and Civil Engineering - UCL, Av. G. Lemaître 4-6, B-1348 Louvain-la-Neuve (Belgium); Hameyer, Kay [Institute of Electrical Machines - RWTH Aachen University, Schinkelstr. 4, D-52056 Aachen (Germany)

2017-03-01

Non-oriented soft magnetic materials are commonly assumed to be magnetically isotropic. However, due to the rolling process a preferred direction exists along the rolling direction. This uniaxial magnetic anisotropy, and the related magnetostriction effect, are critical to the accurate calculation of iron losses and magnetic forces in rotating electrical machines. This paper proposes an extension of an isotropic energy-based vector hysteresis model to account for these two effects. - Highlights: • Energy-based vector hysteresis model with magnetic anisotropy. • Two-scale model to account for pinning field distribution. • Pinning force and reluctivity are extended to anisotropic case.

Ultra high energy cosmic rays and magnetic fields

Energy Technology Data Exchange (ETDEWEB)

Stanev, Todor; Engel, Ralph; Alvarez-Muniz, Jaime; Seckel, David

2002-07-01

We follow the propagation of ultra high energy protons in the presence of random and regular magnetic fields and discuss some of the changes in the angular and energy distributions of these particles introduced by the scattering in the magnetic fields.

Ultra high energy cosmic rays and magnetic fields

International Nuclear Information System (INIS)

Stanev, Todor; Engel, Ralph; Alvarez-Muniz, Jaime; Seckel, David

2002-01-01

We follow the propagation of ultra high energy protons in the presence of random and regular magnetic fields and discuss some of the changes in the angular and energy distributions of these particles introduced by the scattering in the magnetic fields

Small Wind Energy Systems

DEFF Research Database (Denmark)

Simoes, Marcelo; Farret, Felix Alberto; Blaabjerg, Frede

2015-01-01

devices, and a centralized distribution control. In order to establish a small wind energy system it is important to observe the following: (i) Attending the energy requirements of the actual or future consumers; (ii) Establishing civil liabilities in case of accidents and financial losses due to shortage...... or low quality of energy; (iii) Negotiating collective conditions to interconnect the microgrid with the public network or with other sources of energy that is independent of wind resources; (iv) Establishing a performance criteria of power quality and reliability to end-users, in order to reduce costs...... and guaranteeing an acceptable energy supply. This paper discuss how performance is affected by local conditions and random nature of the wind, power demand profiles, turbine related factors, and presents the technical issues for implementing a self-excited induction generator system, or a permanent magnet based...

Calculation of magnetization curves and probability distribution for monoclinic and uniaxial systems

International Nuclear Information System (INIS)

Sobh, Hala A.; Aly, Samy H.; Yehia, Sherif

2013-01-01

We present the application of a simple classical statistical mechanics-based model to selected monoclinic and hexagonal model systems. In this model, we treat the magnetization as a classical vector whose angular orientation is dictated by the laws of equilibrium classical statistical mechanics. We calculate for these anisotropic systems, the magnetization curves, energy landscapes and probability distribution for different sets of relevant parameters and magnetic fields of different strengths and directions. Our results demonstrate a correlation between the most probable orientation of the magnetization vector, the system's parameters, and the external magnetic field. -- Highlights: ► We calculate magnetization curves and probability angular distribution of the magnetization. ► The magnetization curves are consistent with probability results for the studied systems. ► Monoclinic and hexagonal systems behave differently due to their different anisotropies

Magnetic fusion technology

CERN Document Server

Dolan, Thomas J

2014-01-01

Magnetic Fusion Technology describes the technologies that are required for successful development of nuclear fusion power plants using strong magnetic fields. These technologies include: ? magnet systems, ? plasma heating systems, ? control systems, ? energy conversion systems, ? advanced materials development, ? vacuum systems, ? cryogenic systems, ? plasma diagnostics, ? safety systems, and ? power plant design studies. Magnetic Fusion Technology will be useful to students and to specialists working in energy research.

Magnetic fusion energy

International Nuclear Information System (INIS)

Anon.

1978-01-01

The efforts of the Chemical Technology Division in the area of fusion energy include fuel handling, processing, and containment. These studies are closely coordinated with the ORNL Fusion Energy Division. Current experimental studies are concerned with the development of vacuum pumps for fusion reactors, the evaluation and development of techniques for recovering tritium (fuel) from either solid or liquid lithium containing blankets, and the use of deep beds of sorbents as roughing pumps and/or transfer operations. In addition, a small effort is devoted to the support of the ORNL design of The Next Step (TNS) in tokamak reactor development. The more applied studies--vacuum pump development and TNS design--are funded by the DOE/Magnetic Fusion Energy, and the more fundamental studies--blanket recovery and sorption in deep beds--are funded by the DOE/Basic Energy Sciences

Energy dissipation in a finite volume of magnetic fluid

Energy Technology Data Exchange (ETDEWEB)

Bashtovoi, V.; Motsar, A.; Reks, A., E-mail: alexfx20@yandex.ru

2017-06-01

This study is devoted to investigation of energy dissipation processes which happen in a magnetic fluid drop with compound magnet during its motion in cylindrical non magnetic container. The possibility of energy dissipation control by means of electromagnetic field is examined. It's found that a change of magnetic field of compound magnet can lead to both increase and decrease of oscillation decay time and relative damping factor can be varied in a range of ±35%.

Energy transfers in dynamos with small magnetic Prandtl numbers

KAUST Repository

Kumar, Rohit; Verma, Mahendra K.; Samtaney, Ravi

2015-01-01

We perform numerical simulation of dynamo with magnetic Prandtl number Pm = 0.2 on 10243 grid, and compute the energy fluxes and the shell-to-shell energy transfers. These computations indicate that the magnetic energy growth takes place mainly due

Conceptual design of SC magnet system for ITER, (5)

International Nuclear Information System (INIS)

Nakajima, Hideo; Nishi, Masataka; Yoshida, Kiyoshi; Tsuji, Hiroshi; Egusa, Shigenori; Seguchi, Tadao; Hagiwara, Miyuki; Kirk, M.A.; Birtcher, R.C.

1991-08-01

Japan Atomic Energy Research Institute (JAERI) has been developing a superconducting magnet system for a fusion reactor. One of the key items in developing the superconducting magnets is material development and evaluation. The data of superconducting materials, structural alloys, and non-metallic materials are generated to establish a material data base at JAERI. This report is prepared to provide available data generated by JAERI to designers of superconducting magnets throughout the world. The following review papers written for the International Thermonuclear Experimental Reactor (ITER) report on conceptual design of magnet system are combined here. I. Superconducting Material Data II. Mechanical Properties of the Japanese Cryogenic Steels (JCS) at Cryogenic Temperature III. Review of Radiation Degradation Studies at JAERI on Composite Organic Insulators Used in Fusion Magnets (author)

Magnetically levitated autoparametric broadband vibration energy harvesting

International Nuclear Information System (INIS)

Kurmann, L.; Jia, Y.; Manoli, Y.; Woias, P.

2016-01-01

Some of the lingering challenges within the current paradigm of vibration energy harvesting (VEH) involve narrow operational frequency range and the inevitable non-resonant response from broadband noise excitations. Such VEHs are only suitable for limited applications with fixed sinusoidal vibration, and fail to capture a large spectrum of the real world vibration. Various arraying designs, frequency tuning schemes and nonlinear vibratory approaches have only yielded modest enhancements. To fundamentally address this, the paper proposes and explores the potentials in using highly nonlinear magnetic spring force to activate an autoparametric oscillator, in order to realize an inherently broadband resonant system. Analytical and numerical modelling illustrate that high spring nonlinearity derived from magnetic levitation helps to promote the 2:1 internal frequency matching required to activate parametric resonance. At the right internal parameters, the resulting system can intrinsically exhibit semi-resonant response regardless of the bandwidth of the input vibration, including broadband white noise excitation. (paper)

Relaxational dissipation of magnetic field energy in a rarefied plasma

International Nuclear Information System (INIS)

Vekshtejn, G.E.

1987-01-01

A mechanism of solar corona plasma heating connected with relaxation of a magnetic configuration in the corona to the state of the magnetic energy minimum at restrictions imposed by high conductivity of a medium is considered. Photospheric plasma pulsations leading to generation of longitudinal currents in the corona are in this case energy sources. The excess magnetic energy of these currents is dissipated as a result of reclosing of force lines of the magnetic field in narrow current layers. Plasmaturbulence related to the process of magnetic reclosing is phenomenologically described in this case by introducing certain characteristic time of relaxation. Such an approach permits to relate the plasma heating energy with parameters of photospheric motions in the framework of a simple model of the magnetic field

Charge and energy minimization in electrical/magnetic stimulation of nervous tissue.

Science.gov (United States)

Jezernik, Saso; Sinkjaer, Thomas; Morari, Manfred

2010-08-01

In this work we address the problem of stimulating nervous tissue with the minimal necessary energy at reduced/minimal charge. Charge minimization is related to a valid safety concern (avoidance and reduction of stimulation-induced tissue and electrode damage). Energy minimization plays a role in battery-driven electrical or magnetic stimulation systems (increased lifetime, repetition rates, reduction of power requirements, thermal management). Extensive new theoretical results are derived by employing an optimal control theory framework. These results include derivation of the optimal electrical stimulation waveform for a mixed energy/charge minimization problem, derivation of the charge-balanced energy-minimal electrical stimulation waveform, solutions of a pure charge minimization problem with and without a constraint on the stimulation amplitude, and derivation of the energy-minimal magnetic stimulation waveform. Depending on the set stimulus pulse duration, energy and charge reductions of up to 80% are deemed possible. Results are verified in simulations with an active, mammalian-like nerve fiber model.

High-power explosive magnetic energy sources for thermonuclear and physical applications (overview)

Energy Technology Data Exchange (ETDEWEB)

Chernyshev, V K [All-Russian Scientific Institute of Experimental Physics, Sarov (Russian Federation)

1997-12-31

High-power energy sources unavailable up to now are needed to carry out any one project on inertially confined controlled thermonuclear fusion (CTF). Considerable advances have been made in the area of explosive magnetic generators (EGG) as for their output characteristics (high power combined with high energy content). To develop the concept of magnetic cumulation proposed by A.D. Sakharov in 1951, two new approaches to increasing EMC fast operation by two orders (from tens of microseconds to tenths of microseconds) and increasing at the same time the current pulse amplitude by more than one order, were proposed at VNIIEF in the early sixties. The concept aimed at solving the CTF problem by target magnetic compression (MACO) under the effect of an fast-increasing field was proposed (1972) based on VNIIEF achievements, discussed (1976) at the USSR Academy of Sciences and published (1979). The key physical questions are analyzed, the problems to be solved are posed and the results achieved in the experiments with fast-operating high-power EMGs, fast-opening switches, transmitting lines and insulation systems are discussed here. The results obtained in experiments on liner acceleration as well as those on preliminary plasma magnetization and heating, carried out at the constructed EMGs, are discussed briefly. The conclusion is reached that the MACO system is the most suitable one to provide the ignition because the designing of high-power energy sources to be used in this system is practically complete and the concept itself does not need any intermediate transformations of one type of energy into another always accompanied by a decrease in total efficiency. (author). 4 tabs., 14 figs., 21 refs.

Automatic generation control of an interconnected hydrothermal power system considering superconducting magnetic energy storage

Energy Technology Data Exchange (ETDEWEB)

Abraham, Rajesh Joseph; Das, D.; Patra, Amit [Department of Electrical Engineering, Indian Institute of Technology, Kharagpur 721 302 (India)

2007-10-15

This paper presents the analysis of automatic generation control (AGC) of an interconnected hydrothermal power system in the presence of generation rate constraints (GRCs). The improvement of AGC with the addition of a small capacity superconducting magnetic energy storage (SMES) unit in either, as well as in both the areas are studied. Time domain simulations are used to study the performance of the power system and control logic. The optimal values of the integral gain settings are obtained using integral squared error (ISE) technique by minimising a quadratic performance index. Suitable method for controlling the SMES unit is described. Analysis reveals that SMES unit fitted in either of the areas is as effective as SMES units fitted in both the areas and improves the dynamic performances to a considerable extent following a load disturbance in either of the areas. (author)

Energy conservation and environmental benefits that may be realized from Superconducting Magnetic Energy Storage

International Nuclear Information System (INIS)

Baumann, P.D.

1992-01-01

This paper discusses the Superconducting Magnetic Energy Storage (SMES) technology which has the capability to significantly improve electrical system operations within electric utility systems. This has been demonstrated by Bonneville Power Administration in a 30-MJ SMES demonstration unit. Savings in utility operations from improved system efficiency, increased reliability, and reduced maintenance requirements contribute to the economic justification of SMES. Beyond these benefits, there are additional benefits which in the long run may significantly outweigh the electrical operational benefits. These benefits are the energy conservation and environmental benefits. Since SMES can uncouple generation from load, it can shift generation around, thereby changing the operational characteristics of the system. The technology has the capability of reducing fuel consumption which can in turn reduce emissions. In a regional setting it can potentially shift emissions both in volumes and in physical areas to avoid problem situations. With its capability to strategically shift generation and significantly affect emissions and air quality it can stretch clean energy generation options. With these attributes, SMES can be recognized as an energy and environmental management technology and tool

Injection system of teh SSC Medium Energy Booster

International Nuclear Information System (INIS)

Mao, N.; Gerig, R.; McGill, J.; Brown, K.

1994-04-01

The Medium Energy Booster (MEB) is the third of the SSCL accelerators and the largest of the resistive magnet synchrotrons. It accelerates protons from an injection momentum of 12 GeV/c to a top momentum of 200 GeV/c. A beam injection system has been designed to inject the beam transferred from the Low Energy Booster onto the MEB closed orbit in the MEB injection insertion region. The beam is injected via a vertical bending Lambertson septum magnet and a horizontal kicker with appropriate matching and very little beam loss and emittance dilution. The beam optics of the injection system is described in this paper. The required parameters of the Lambertson septum magnet and the injection kicker are given

Magnetic energy storage devices for small scale applications

International Nuclear Information System (INIS)

Kumar, B.

1992-01-01

This paper covers basic principles of magnetic energy storage, structure requirements and limitations, configurations of inductors, attributes of high-T c superconducting materials including thermal instabilities, a relative comparison with the state-of-the-art high energy density power sources, and refrigeration requirements. Based on these fundamental considerations, the design parameters of a micro superconducting magnetic energy unit for Air Force applications is presented and discussed

Comments on open-ended magnetic systems for fusion

International Nuclear Information System (INIS)

Post, R.F.

1990-01-01

Differentiating characteristics of magnetic confinement systems having externally generated magnetic fields that are ''open'' are listed and discussed in the light of their several potential advantages for fusion power systems. It is pointed out that at this stage of fusion research ''high-Q'' (as deduced from long energy confinement times) is not necessarily the most relevant criterion by which to judge the potential of alternate fusion approaches for the economic generation of fusion power. An example is given of a hypothetical open-geometry fusion power system where low-Q operation is essential to meeting one of its main objectives (low neutron power flux)

Asymmetry in the convective energy fluxes due to electrostatic and magnetic fluctuations in magnetized plasmas

International Nuclear Information System (INIS)

Smolyakov, A.I.; Hirose, A.

1993-01-01

The structure of the energy balance equation for a magnetically confined plasma in the presence of electromagnetic fluctuations is investigated by using the drift kinetic equation. The convective energy fluxes, one caused by E x B electrostatic turbulence and the other by shear-Alfven type magnetic turbulence, are asymmetric: For low frequency electrostatic turbulence, the convective energy flux has a unique numerical factor 3/2, while the convective energy flux induced by magnetic turbulence has a numerical factor 5/2. As expected, in the drift approximation, turbulent heating by the longitudinal electric field is the only anomalous source term in the total energy balance equation. (Author)

Fusion energy in an inertial electrostatic confinement device using a magnetically shielded grid

Energy Technology Data Exchange (ETDEWEB)

Hedditch, John, E-mail: john.hedditch@sydney.edu.au; Bowden-Reid, Richard, E-mail: rbow3948@physics.usyd.edu.au; Khachan, Joe, E-mail: joe.khachan@sydney.edu.au [School of Physics, The University of Sydney, Sydney, New South Whales 2006 (Australia)

2015-10-15

Theory for a gridded inertial electrostatic confinement (IEC) fusion system is presented, which shows a net energy gain is possible if the grid is magnetically shielded from ion impact. A simplified grid geometry is studied, consisting of two negatively biased coaxial current-carrying rings, oriented such that their opposing magnetic fields produce a spindle cusp. Our analysis indicates that better than break-even performance is possible even in a deuterium-deuterium system at bench-top scales. The proposed device has the unusual property that it can avoid both the cusp losses of traditional magnetic fusion systems and the grid losses of traditional IEC configurations.

Parametric design studies of toroidal magnetic energy storage units

International Nuclear Information System (INIS)

Herring, J.S.

1990-01-01

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

Parametric design studies of toroidal magnetic energy storage units

Science.gov (United States)

Herring, J. Stephen

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

Energy flux due to electromagnetic fluctuations during guide field magnetic reconnection

International Nuclear Information System (INIS)

Kuwahata, Akihiro; Inomoto, Michiaki; Ono, Yasushi; Yanai, Ryoma

2016-01-01

Large electromagnetic fluctuations inside the current sheet and large reconnection electric fields are observed during fast magnetic reconnection in the presence of a guide field. The fluctuations transport 2.5% of the dissipated magnetic energy from the reconnection region. Although the energy gains of the ions and electrons are approximately 60% and 12%, respectively, of the dissipated magnetic energy after the fast reconnection, the energy of fluctuations is not comparable to their energy gains. The fluctuations do not directly contribute to the energy conversion but might cause the fast reconnection leading to the rapid release of magnetic energy. (author)

Quantum control of topological defects in magnetic systems

Science.gov (United States)

Takei, So; Mohseni, Masoud

2018-02-01

Energy-efficient classical information processing and storage based on topological defects in magnetic systems have been studied over the past decade. In this work, we introduce a class of macroscopic quantum devices in which a quantum state is stored in a topological defect of a magnetic insulator. We propose noninvasive methods to coherently control and read out the quantum state using ac magnetic fields and magnetic force microscopy, respectively. This macroscopic quantum spintronic device realizes the magnetic analog of the three-level rf-SQUID qubit and is built fully out of electrical insulators with no mobile electrons, thus eliminating decoherence due to the coupling of the quantum variable to an electronic continuum and energy dissipation due to Joule heating. For a domain wall size of 10-100 nm and reasonable material parameters, we estimate qubit operating temperatures in the range of 0.1-1 K, a decoherence time of about 0.01-1 μ s , and the number of Rabi flops within the coherence time scale in the range of 102-104 .

CLIQ – Coupling-Loss Induced Quench System for Protecting Superconducting Magnets

CERN Multimedia

Ravaioli, E; Kirby, G; ten Kate, H H J; Verweij, A P

2014-01-01

The recently developed Coupling-Loss-Induced Quench (CLIQ) protection system is a new method for initiating a fast and voluminous transition to the normal state for protecting high energy density superconducting magnets. Upon quench detection, CLIQ is triggered to generate an oscillating current in the magnet coil by means of a capacitive discharge. This in turn introduces a high coupling loss in the superconductor which provokes a quick transition to the normal state of the coil windings. The system is now implemented for the protection of a two meter long superconducting quadrupole magnet and characterized in the CERN magnet test facility. Various CLIQ configurations with different current injection points are tested and the results compared to similar transients lately measured with a not optimized configuration. Test results convincingly show that the newly tested design allows for a more global quench initiation and thus a faster discharge of the magnet energy. Moreover, the performance of CLIQ for reduc...

Concept of magnet systems for LHD-type reactor

International Nuclear Information System (INIS)

Imagawa, S.; Takahata, K.; Tamura, H.; Yanagi, N.; Mito, T.; Obana, T.; Sagara, A.

2008-10-01

Heliotron reactors have attractive features for fusion power plants, such as no need for current drive and a wide space between the helical coils for the maintenance of in-vessel components. Their main disadvantage was considered the necessarily large size of their magnet systems. According to the recent reactor studies based on the experimental results in the Large Helical Device, the major radius of plasma of 14 to 17 m with a central toroidal field of 6 to 4 T is needed to attain the self-ignition condition with a blanket space thicker than 1.1 m. The stored magnetic energy is estimated at 120 to 140 GJ. Although both the major radius and the magnetic energy are about three times as large as ITER, the maximum magnetic field and mechanical stress can be comparable. In the preliminary structural analysis, the maximum stress intensity including the peak stress is less than 1,000 MPa that is allowed for strengthened stainless steel. Although the length of the helical coil is longer than 150 m that is about five times as long as the ITER TF coil, cable-in-conduit conductors can be adopted with a parallel winding method of five-in-hand. The concept of the parallel winding is proposed. Consequently, the magnet systems for helical reactors can be realized with small extension of the ITER technology. (author)

A new hybrid protection system for high-field superconducting magnets

CERN Document Server

Ravaioli, E; Kirby, G; ten Kate, H H J; Verweij, A P

2014-01-01

The new generation of high-field superconducting accelerator magnets poses a challenge concerning the protection of the magnet coil in the case of a quench. The very high stored energy per unit volume requires a fast and efficient quench heating system in order to avoid damage due to overheating. A new protection system for superconducting magnets is presented, comprising a combination of a novel coupling-loss induced quench (CLIQ) system and conventional quench heaters. CLIQ can provoke a very fast transition to the normal state in coil windings by introducing coupling loss and thus heat in the coil's conductor. The advantage of the hybrid protection system is a global transition, resulting in a much faster current decay, a significantly lower hot-spot temperature, and a more homogeneous temperature distribution in the magnet's coil.

Magnetic energy analyser for slow electrons

International Nuclear Information System (INIS)

Limberg, W.

1974-08-01

A differential spectrometer with high time and energy resolution has been developed using the principle of energy analysis with a longitudinal homogeneous magnetic field. This way it is possible to measure the energy distribution of low energy electrons (eV-range) in the presence of high energy electrons without distortions by secondary electrons. The functioning and application of the analyzer is demonstrated by measuring the energy distributions of slow electrons emitted by a filament. (orig.) [de

A feasibility demonstration program for superconducting magnetic energy storage

International Nuclear Information System (INIS)

Filios, P.G.

1988-01-01

The Defense Nuclear Agency, as the agent of the Strategic Defense Initiative (SDI) Office, has begun a program to build an engineering test model (ETM) of a superconducting magnetic energy storage (SMES) system. The ETM will serve to demonstrate the feasibility of using SMES technology to meet both SDI and public utility requirements for electric energy storage. SMES technology characteristics are reviewed and related to SDI and electric utility requirements. Program structure and schedule are related to specific objectives, and critical issues are defined

Summary of the report of the Senior Committee on Environmental, Safety, and Economic Aspects of Magnetic Fusion Energy

International Nuclear Information System (INIS)

Holdren, J.P.; Berwald, D.H.; Budnitz, R.J.

1987-01-01

The Senior Committee on Environmental, Safety, and Economic Aspects of Magnetic Fusion Energy (ESECOM) has assessed magnetic fusion energy's prospects for providing energy with economic, environmental, and safety characteristics that would be attractive compared with other energy sources (mainly fission) available in the year 2015 and beyond. ESECOM gives particular attention to the interaction of environmental, safety, and economic characteristics of a variety of magnetic fusion reactors, and compares them with a variety of fission cases. Eight fusion cases, two fusion-fission hybrid cases, and four fission cases are examined, using consistent economic and safety models. These models permit exploration of the environmental, safety, and economic potential of fusion concepts using a wide range of possible materials choices, power densities, power conversion schemes, and fuel cycles. The ESECOM analysis indicates that magnetic fusion energy systems have the potential to achieve costs-of-electricity comparable to those of present and future fission systems, coupled with significant safety and environmental advantages. 75 refs., 2 figs., 24 tabs

Magnetic Coordinate Systems

Science.gov (United States)

Laundal, K. M.; Richmond, A. D.

2017-03-01

Geospace phenomena such as the aurora, plasma motion, ionospheric currents and associated magnetic field disturbances are highly organized by Earth's main magnetic field. This is due to the fact that the charged particles that comprise space plasma can move almost freely along magnetic field lines, but not across them. For this reason it is sensible to present such phenomena relative to Earth's magnetic field. A large variety of magnetic coordinate systems exist, designed for different purposes and regions, ranging from the magnetopause to the ionosphere. In this paper we review the most common magnetic coordinate systems and describe how they are defined, where they are used, and how to convert between them. The definitions are presented based on the spherical harmonic expansion coefficients of the International Geomagnetic Reference Field (IGRF) and, in some of the coordinate systems, the position of the Sun which we show how to calculate from the time and date. The most detailed coordinate systems take the full IGRF into account and define magnetic latitude and longitude such that they are constant along field lines. These coordinate systems, which are useful at ionospheric altitudes, are non-orthogonal. We show how to handle vectors and vector calculus in such coordinates, and discuss how systematic errors may appear if this is not done correctly.

Conversion of magnetic energy to runaway kinetic energy during the termination of runaway current on the J-TEXT tokamak

Science.gov (United States)

Dai, A. J.; Chen, Z. Y.; Huang, D. W.; Tong, R. H.; Zhang, J.; Wei, Y. N.; Ma, T. K.; Wang, X. L.; Yang, H. Y.; Gao, H. L.; Pan, Y.; the J-TEXT Team

2018-05-01

A large number of runaway electrons (REs) with energies as high as several tens of mega-electron volt (MeV) may be generated during disruptions on a large-scale tokamak. The kinetic energy carried by REs is eventually deposited on the plasma-facing components, causing damage and posing a threat on the operation of the tokamak. The remaining magnetic energy following a thermal quench is significant on a large-scale tokamak. The conversion of magnetic energy to runaway kinetic energy will increase the threat of runaway electrons on the first wall. The magnetic energy dissipated inside the vacuum vessel (VV) equals the decrease of initial magnetic energy inside the VV plus the magnetic energy flowing into the VV during a disruption. Based on the estimated magnetic energy, the evolution of magnetic-kinetic energy conversion are analyzed through three periods in disruptions with a runaway current plateau.

TPC magnet cryogenic system

International Nuclear Information System (INIS)

Green, M.A.; Burns, W.A.; Taylor, J.D.; Van Slyke, H.W.

1980-03-01

The Time Projection Chamber (TPC) magnet at LBL and its compensation solenoids are adiabatically stable superconducting solenoid magnets. The cryogenic system developed for the TPC magnet is discussed. This system uses forced two-phase tubular cooling with the two cryogens in the system. The liquid helium and liquid nitrogen are delivered through the cooled load by forced tubular flow. The only reservoirs of liquid cryogen exist in the control dewar (for liquid helium) and the conditioner dewar (for liquid nitrogen). The operation o these systems during virtually all phases of system operation are described. Photographs and diagrams of various system components are shown, and cryogenic system data are presented in the following sections: (1) heat leaks into the TPC coil package and the compensation solenoids; (2) heat leaks to various components of the TPC magnet cryogenics system besides the magnets and control dewar; (3) the control dewar and its relationship to the rest of the system; (4) the conditioner system and its role in cooling down the TPC magnet; (5) gas-cooled electrical leads and charging losses; and (6) a summation of the liquid helium and liquid nitrogen requirements for the TPC superconducting magnet system

Superconductive energy storage magnet study

International Nuclear Information System (INIS)

Rhee, S.W.

1982-01-01

Among many methods of energy storages the superconducting energy storage has been considered as the most promising method. Many related technical problems are still unsolved. One of the problems is the magnetizing and demagnetizing loss of superconducting coil. This loss is mainly because of hysteresis of pinning force. In this paper the hysteresis loss is calculated and field dependence of the a.c. losses is explained. The ratio of loss and stored energy is also calculated. (Author)

Energy dump of the ATLAS superconducting system simulations of electrical and thermal behaviour of magnet system at slow- and fast dump

CERN Document Server

van Beek, Martijn; Dudarev, A

During the slow dump (discharge) of the Barrel Toroidal (superconducting) magnet of the ATLAS detector, the control system gave an alarm that the differences between the voltages over the conductors were too high. The alarm was not due to any danger, because of some sort of phenomenon observed in the first few seconds after start of the discharge. A possible explanation of the differences of the coil voltages is that the changing current through the conductors may cause induced currents in the coil casing around. The goal was to make a simulation of the electrical behaviour of the magnet system during a slow dump. In this way, an explanation can be found for the start phenomenon of the slow dump of the Barrel Toroid. Some extra analyses on the measurements were performed to describe the energy dissipation during a fast dump. This is done by calculating the resistance of the coils during the dump. With the maximum resistance, the maximum temperature can be estimated, which says something about the enthalpy of ...

Study of superconducting magnetic bearing applicable to the flywheel energy storage system that consist of HTS-bulks and superconducting-coils

International Nuclear Information System (INIS)

Seino, Hiroshi; Nagashima, Ken; Tanaka, Yoshichika; Nakauchi, Masahiko

2010-01-01

The Railway Technical Research Institute conducted a study to develop a superconducting magnetic bearing applicable to the flywheel energy-storage system for railways. In the first step of the study, the thrust rolling bearing was selected for application, and adopted liquid-nitrogen-cooled HTS-bulk as a rotor, and adopted superconducting coil as a stator for the superconducting magnetic bearing. Load capacity of superconducting magnetic bearing was verified up to 10 kN in the static load test. After that, rotation test of that approximately 5 kN thrust load added was performed with maximum rotation of 3000rpm. In the results of bearing rotation test, it was confirmed that position in levitation is able to maintain with stability during the rotation. Heat transfer properties by radiation in vacuum and conductivity by tenuous gas were basically studied by experiment by the reason of confirmation of rotor cooling method. The experimental result demonstrates that the optimal gas pressure is able to obtain without generating windage drag. In the second stage of the development, thrust load capacity of the bearing will be improved aiming at the achievement of the energy capacity of a practical scale. In the static load test of the new superconducting magnetic bearing, stable 20kN-levitation force was obtained.

An eddy current-induced magnetic plucking for piezoelectric energy harvesting

International Nuclear Information System (INIS)

Do, Nam Ho; Baek, Yoon Su

2016-01-01

Frequency up-conversion is a very efficient method of energy harvesting in order to overcome low, non-periodic, or altered ambient vibration. In order to perform frequency up-conversion and transference of mechanical energy without contact, an eddy current-induced magnetic drag force is used. In this paper, we present a novel configuration of eddy current-induced magnetic plucking for piezoelectric energy harvesting. Our method consists of two permanent magnets, a piezoelectric beam, and a copper disk piece. We design our harvesting method to achieve loading, sudden release, and free vibration using the actuation of the piezoelectric beam through the magnetic mutual coupling between the magnet and copper disk piece. We present the principle of magnetic drag force-generation, characterize the energy harvesting performance of our harvesting method, and demonstrate our harvesting method’s capability of frequency up-conversion and transference of mechanical energy without contact under low, non-periodic, or altered ambient vibration. To that end, we describe the calculation of magnetic drag force with various geometric dimensions and material properties, model of the piezoelectric cantilever beam, comparison between estimation response and measured experiment response, and the measured voltage and power responses. (paper)

Calibration Measurements of the LHC Beam Dumping System Extraction Kicker Magnets

CERN Document Server

Uythoven, J; Ducimetière, L; Goddard, B; Gräwer, G; Olivieri, F; Pereira, L; Vossenberg, Eugène B

2006-01-01

The LHC beam dumping system must protect the LHC machine from damage by reliably and safely extracting and absorbing the circulating beams when requested. Two sets of 15 extraction kicker magnets form the main active part of this system. They have been produced, tested and calibrated by measuring the integrated magnetic field and the magnet current at different beam energies. The calibration data have been analysed, and the critical parameters are compared with the specifications. Implications for the configuration, control and operation of the beam dumping system are discussed.

Principle of Minimum Energy in Magnetic Reconnection in a Self-organized Critical Model for Solar Flares

Science.gov (United States)

Farhang, Nastaran; Safari, Hossein; Wheatland, Michael S.

2018-05-01

Solar flares are an abrupt release of magnetic energy in the Sun’s atmosphere due to reconnection of the coronal magnetic field. This occurs in response to turbulent flows at the photosphere that twist the coronal field. Similar to earthquakes, solar flares represent the behavior of a complex system, and expectedly their energy distribution follows a power law. We present a statistical model based on the principle of minimum energy in a coronal loop undergoing magnetic reconnection, which is described as an avalanche process. We show that the distribution of peaks for the flaring events in this self-organized critical system is scale-free. The obtained power-law index of 1.84 ± 0.02 for the peaks is in good agreement with satellite observations of soft X-ray flares. The principle of minimum energy can be applied for general avalanche models to describe many other phenomena.

Superconducting energy storage magnet

Science.gov (United States)

Boom, Roger W. (Inventor); Eyssa, Yehia M. (Inventor); Abdelsalam, Mostafa K. (Inventor); Huang, Xianrui (Inventor)

1993-01-01

A superconducting magnet is formed having composite conductors arrayed in coils having turns which lie on a surface defining substantially a frustum of a cone. The conical angle with respect to the central axis is preferably selected such that the magnetic pressure on the coil at the widest portion of the cone is substantially zero. The magnet structure is adapted for use as an energy storage magnet mounted in an earthen trench or tunnel where the strength the surrounding soil is lower at the top of the trench or tunnel than at the bottom. The composite conductor may be formed having a ripple shape to minimize stresses during charge up and discharge and has a shape for each ripple selected such that the conductor undergoes a minimum amount of bending during the charge and discharge cycle. By minimizing bending, the working of the normal conductor in the composite conductor is minimized, thereby reducing the increase in resistance of the normal conductor that occurs over time as the conductor undergoes bending during numerous charge and discharge cycles.

Progress with High-Field Superconducting Magnets for High-Energy Colliders

Science.gov (United States)

Apollinari, Giorgio; Prestemon, Soren; Zlobin, Alexander V.

2015-10-01

One of the possible next steps for high-energy physics research relies on a high-energy hadron or muon collider. The energy of a circular collider is limited by the strength of bending dipoles, and its maximum luminosity is determined by the strength of final focus quadrupoles. For this reason, the high-energy physics and accelerator communities have shown much interest in higher-field and higher-gradient superconducting accelerator magnets. The maximum field of NbTi magnets used in all present high-energy machines, including the LHC, is limited to ˜10 T at 1.9 K. Fields above 10 T became possible with the use of Nb3Sn superconductors. Nb3Sn accelerator magnets can provide operating fields up to ˜15 T and can significantly increase the coil temperature margin. Accelerator magnets with operating fields above 15 T require high-temperature superconductors. This review discusses the status and main results of Nb3Sn accelerator magnet research and development and work toward 20-T magnets.

Energy transport in cooling device by magnetic fluid

Science.gov (United States)

Yamaguchi, Hiroshi; Iwamoto, Yuhiro

2017-06-01

Temperature sensitive magnetic fluid has a great potential with high performance heat transport ability as well as long distance energy (heat) transporting. In the present study experimental set-up was newly designed and constructed in order to measure basic heat transport characteristics under various magnetic field conditions. Angular dependence for the device (heat transfer section) was also taken into consideration for a sake of practical applications. The energy transfer characteristic (heat transport capability) in the magnetically-driven heat transport (cooling) device using the binary TSMF was fully investigated with the set-up. The obtained results indicate that boiling of the organic mixture (before the magnetic fluid itself reaching boiling point) effectively enhances the heat transfer as well as boosting the flow to circulate in the closed loop by itself. A long-distance heat transport of 5 m is experimentally confirmed, transferring the thermal energy of 35.8 W, even when the device (circulation loop) is horizontally placed. The highlighted results reveal that the proposed cooling device is innovative in a sense of transporting substantial amount of thermal energy (heat) as well as a long distance heat transport. The development of the magnetically-driven heat transport device has a great potential to be replaced for the conventional heat pipe in application of thermal engineering.

Magnetic Actuation of Biological Systems

Science.gov (United States)

Lauback, Stephanie D.

Central to the advancement of many biomedical and nanotechnology capabilities is the capacity to precisely control the motion of micro and nanostructures. These applications range from single molecule experiments to cell isolation and separation, to drug delivery and nanomachine manipulation. This dissertation focuses on actuation of biological micro- and nano-entities through the use of weak external magnetic fields, superparamagnetic beads, and ferromagnetic thin films. The magnetic platform presents an excellent method for actuation of biological systems due to its ability to directly control the motion of an array of micro and nanostructures in real-time with calibrated picoNewton forces. The energy landscape of two ferromagnetic thin film patterns (disks and zigzag wires) is experimentally explored and compared to corresponding theoretical models to quantify the applied forces and trajectories of superparamagnetic beads due to the magnetic traps. A magnetic method to directly actuate DNA nanomachines in real-time with nanometer resolution and sub-second response times using micromagnetic control was implemented through the use of stiff DNA micro-levers which bridged the large length scale mismatch between the micro-actuator and the nanomachine. Compared to current alternative methods which are limited in the actuation speeds and the number of reconfiguration states of DNA constructs, this magnetic approach enables fast actuation (˜ milliseconds) and reconfigurable conformations achieved through a continuous range of finely tuned steps. The system was initially tested through actuation of the stiff arm tethered to the surface, and two prototype DNA nanomachines (rotor and hinge) were successfully actuated using the stiff mechanical lever. These results open new possibilities in the development of functional robotic systems at the molecular scale. In exploiting the use of DNA stiff levers, a new technique was also developed to investigate the emergence of the

Pulsed Power Supply Based on Magnetic Energy Storage for Non-Destructive High Field Magnets

Science.gov (United States)

Aubert, G.; Defoug, S.; Joss, W.; Sala, P.; Dubois, M.; Kuchinsk, V.

2004-11-01

The first test results of a recently built pulsed power supply based on magnetic energy storage will be described. The system consists of the 16 kV shock alternator with a short-circuit power of 3600 MVA of the VOLTA Testing Center of the Schneider Electric SA company, a step-down transformer with a ratio of 1/24, a three-phase diode bridge designed for a current rising exponentially to 120 kA, and a big, 10 ton, heavy, 10 mH aluminum storage coil. The system is designed to store 72 MJ, normal operation will be at 50 MJ, and will work with voltages up to 20 kV. A transfer of 20% of the stored energy into the high field coil should be possible. Special making switches and interrupters have been developed to switch the high currents in a very short time. For safety and redundancy two independent monitoring systems control the energy transfer. A sequencing control system operates the switches on the ac side and protective switches on the dc side, a specially developed real-time control-monitoring system checks several currents and voltages and commands the dc circuit breakers and making switches.

Dynamical Origin of Highly Efficient Energy Dissipation in Soft Magnetic Nanoparticles for Magnetic Hyperthermia Applications

Science.gov (United States)

Kim, Min-Kwan; Sim, Jaegun; Lee, Jae-Hyeok; Kim, Miyoung; Kim, Sang-Koog

2018-05-01

We explore robust magnetization-dynamic behaviors in soft magnetic nanoparticles in single-domain states and find their related high-efficiency energy-dissipation mechanism using finite-element micromagnetic simulations. We also make analytical derivations that provide deeper physical insights into the magnetization dynamics associated with Gilbert damping parameters under applications of time-varying rotating magnetic fields of different strengths and frequencies and static magnetic fields. Furthermore, we find that the mass-specific energy-dissipation rate at resonance in the steady-state regime changes remarkably with the strength of rotating fields and static fields for given damping constants. The associated magnetization dynamics are well interpreted with the help of the numerical calculation of analytically derived explicit forms. The high-efficiency energy-loss power can be obtained using soft magnetic nanoparticles in the single-domain state by tuning the frequency of rotating fields to the resonance frequency; what is more, it is controllable via the rotating and static field strengths for a given intrinsic damping constant. We provide a better and more efficient means of achieving specific loss power that can be implemented in magnetic hyperthermia applications.

The LHC magnet system and its status of development

Science.gov (United States)

Bona, Maurizio; Perin, Romeo; Vlogaert, Jos

1995-01-01

CERN is preparing for the construction of a new high energy accelerator/collider, the Large Hadron Collider (LHC). This new facility will mainly consist of two superconducting magnetic beam channels, 27 km long, to be installed in the existing LEP tunnel. The magnetic system comprises about 1200 twin-aperture dipoles, 13.145 m long, with an operational field of 8.65 T, about 600 quadrupoles, 3 m long, and a very large number of other superconducting magnetic components. A general description of the system is given together with the main features of the design of the regular lattice magnets. The paper also describes the present state of the magnet R & D program. Results from short model work, as well as from full scale prototypes will be presented, including the recently tested 10 m long full-scale prototype dipole manufactured in industry.

How systems of single-molecule magnets magnetize at low temperatures

Science.gov (United States)

Fernández, Julio F.; Alonso, Juan J.

2004-01-01

We model magnetization processes that take place through tunneling in crystals of single-molecule magnets, such as Mn12 and Fe8. These processes take place when a field H is applied after quenching to very low temperatures. Magnetic dipolar interactions and spin-flipping rules are essential ingredients of the model. The results obtained follow from Monte Carlo simulations and from the stochastic model we propose for dipole field diffusion. Correlations established before quenching are shown to later drive the magnetization process. We also show that in simple cubic lattices, m∝√(t) at time t after H is applied, as observed in Fe8, but only for 1+2log10(hd/hw) time decades, where hd is some near-neighbor magnetic dipolar field, and a spin reversal can occur only if the magnetic field acting on it is within some field window (-hw,hw). However, the √(t) behavior is not universal. For bcc and fcc lattices, m∝tp, but p≃0.7. An expression for p in terms of lattice parameters is derived. At later times the magnetization levels off to a constant value. All these processes take place at approximately constant magnetic energy if the annealing energy ɛa is larger than the tunneling window’s energy width (i.e., if ɛa≳gμBhwS). Thermal processes come in only later on to drive further magnetization growth.

A new hybrid protection system for high-field superconducting magnets

NARCIS (Netherlands)

Ravaioli, Emanuele; Datskov, V.I.; Kirby, G.; ten Kate, Herman H.J.; Verweij, A.P.

2014-01-01

The new generation of high-field superconducting accelerator magnets poses a challenge concerning the protection of the magnet coil in the case of a quench. The very high stored energy per unit volume requires a fast and efficient quench heating system in order to avoid damage due to overheating. A

Development of large high current density superconducting solenoid magnets for use in high energy physics experiments

International Nuclear Information System (INIS)

Green, M.A.

1977-05-01

The development of a unique type of large superconducting solenoid magnet, characterized by very high current density windings and a two-phase helium tubular cooling system is described. The development of the magnet's conceptual design and the construction of two test solenoids are described. The successful test of the superconducting coil and its tubular cooling refrigeration system is presented. The safety, environmental and economic impacts of the test program on future developments in high energy physics are shown. Large solid angle particle detectors for colliding beam physics will analyze both charged and neutral particles. In many cases, these detectors will require neutral particles, such as gamma rays, to pass through the magnet coil with minimum interaction. The magnet coils must be as thin as possible. The use of superconducting windings allows one to minimize radiation thickness, while at the same time maximizing charged particle momentum resolution and saving substantial quantities of electrical energy. The results of the experimental measurements show that large high current density solenoid magnets can be made to operate at high stored energies. The superconducting magnet development described has a positive safety and environmental impact. The use of large high current density thin superconducting solenoids has been proposed in two high energy physics experiments to be conducted at the Stanford Linear Accelerator Center and Cornell University as a result of the successful experiments described

EVOLUTION OF MAGNETIC HELICITY AND ENERGY SPECTRA OF SOLAR ACTIVE REGIONS

International Nuclear Information System (INIS)

Zhang, Hongqi; Brandenburg, Axel; Sokoloff, D. D.

2016-01-01

We adopt an isotropic representation of the Fourier-transformed two-point correlation tensor of the magnetic field to estimate the magnetic energy and helicity spectra as well as current helicity spectra of two individual active regions (NOAA 11158 and NOAA 11515) and the change of the spectral indices during their development as well as during the solar cycle. The departure of the spectral indices of magnetic energy and current helicity from 5/3 are analyzed, and it is found that it is lower than the spectral index of the magnetic energy spectrum. Furthermore, the fractional magnetic helicity tends to increase when the scale of the energy-carrying magnetic structures increases. The magnetic helicity of NOAA 11515 violates the expected hemispheric sign rule, which is interpreted as an effect of enhanced field strengths at scales larger than 30–60 Mm with opposite signs of helicity. This is consistent with the general cycle dependence, which shows that around the solar maximum the magnetic energy and helicity spectra are steeper, emphasizing the large-scale field

EVOLUTION OF MAGNETIC HELICITY AND ENERGY SPECTRA OF SOLAR ACTIVE REGIONS

Energy Technology Data Exchange (ETDEWEB)

Zhang, Hongqi [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Brandenburg, Axel [Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-10691 Stockholm (Sweden); Sokoloff, D. D., E-mail: hzhang@bao.ac.cn [Department of Physics, Moscow University, 119992 Moscow (Russian Federation)

2016-03-10

We adopt an isotropic representation of the Fourier-transformed two-point correlation tensor of the magnetic field to estimate the magnetic energy and helicity spectra as well as current helicity spectra of two individual active regions (NOAA 11158 and NOAA 11515) and the change of the spectral indices during their development as well as during the solar cycle. The departure of the spectral indices of magnetic energy and current helicity from 5/3 are analyzed, and it is found that it is lower than the spectral index of the magnetic energy spectrum. Furthermore, the fractional magnetic helicity tends to increase when the scale of the energy-carrying magnetic structures increases. The magnetic helicity of NOAA 11515 violates the expected hemispheric sign rule, which is interpreted as an effect of enhanced field strengths at scales larger than 30–60 Mm with opposite signs of helicity. This is consistent with the general cycle dependence, which shows that around the solar maximum the magnetic energy and helicity spectra are steeper, emphasizing the large-scale field.

The free energies of partially open coronal magnetic fields

Science.gov (United States)

Low, B. C.; Smith, D. F.

1993-01-01

A simple model of the low corona is examined in terms of a static polytropic atmosphere in equilibrium with a global magnetic field. The question posed is whether magnetostatic states with partially open magnetic fields may contain magnetic energies in excess of those in fully open magnetic fields. Based on the analysis presented here, it is concluded that the cross-field electric currents in the pre-eruption corona are a viable source of the bulk of the energies in a mass ejection and its associated flare.

Overview of stoppering of open magnetic containment systems for controlled fusion

International Nuclear Information System (INIS)

Hinrichs, C.K.; Lichtenberg, A.J.; Dolan, T.J.

1977-06-01

Magnetic confinement systems with the field lines leading out of the system are subject to end loss. The rate of end loss must be reduced to a sufficiently small value in a reactor such that fusion energy is generated more rapidly than energy is lost. The basic open ended systems either have too high an end loss to satisfy the reactor criterion (single mirrors and cusps), or are too long to be considered practical (long solenoids). Various end stoppering schemes have been proposed to reduce the end loss of open ended systems, and thus make the energy balance more favorable. The end stoppering techniques reviewed in this paper are electrostatic, r.f., magnetic, material walls, and hybrid systems. We summarize here the more important characteristics and the potentialities of the first three methods of end stoppering. End stoppering with material walls has been insufficiently explored for further comment and hybrid systems, being mainly beyond the scope of this report, have been summarized in the main text

Direct fission fragment energy converter - Magnetic collimator option

International Nuclear Information System (INIS)

Tsvetkov, P. V.; Hart, R. R.

2006-01-01

The present study was focused on developing a technologically feasible power system that is based on direct fission fragment energy conversion utilizing magnetic collimation. The new concept is an attempt to combine several advantageous design solutions, which have been proposed for application in both fission and fusion reactors, into one innovative system that can offer exceptional energy conversion efficiency. The analysis takes into consideration a wide range of operational aspects including fission fragment escape from the fuel, collimation, collection, criticality, long-term performance, energy conversion efficiency, heat removal, and safety characteristics. Specific characteristics of the individual system components and the entire system are evaluated. Analysis and evaluation of the technological feasibility of the concept were achieved using state-of-the-art computer codes that allowed realistic and consistent modeling. In addition to the extensive computational effort, the scaled prototype experimental proof-of-principle program was conducted to validate basic physics of the concept. The program was focused on electromagnetic components and experimental demonstration of performance. This paper summarizes the final results of the 6-years research program including both computational and experimental efforts. Potential future research and development and anticipated applications are discussed. (authors)

Photovoltaic power systems energy storage

International Nuclear Information System (INIS)

Buldini, P.L.

1991-01-01

Basically, the solar photovoltaic power system consists of: Array of solar panels; Charge/voltage stabilizer; Blocking diode and Storage device. The storage device is a very important part of the system due to the necessity to harmonize the inevitable time shift between energy supply and demand. As energy storage, different devices can be utilized, such as hydropumping, air or other gas compression, flywheel, superconducting magnet, hydrogen generation and so on, but actually secondary (rechargeable) electrochemical cells appear to be the best storage device, due to the direct use for recharge of the d.c. current provided by the solar panels, without any intermediate step of energy transformation and its consequent loss of efficiency

APPLICATION OF NONLINEAR PID CONTROLLER IN SUPERCONDUCTING MAGNETIC ENERGY STORAGE

OpenAIRE

PENG, Xiaotao; CHENG, Shijie

2011-01-01

As a new control strategy, Nonlinear PID(NLPID) controller has been introduced in the power system successfully. The controller is free of planting model foundation in the design procedure and realized simply. In this paper, a nonlinear PID controller used for superconducting magnetic energy storage (SMES) unit connected to a power system is proposed. Purpose of designing such controller is to improve the stability of the power system in a relatively wide operation range. The design procedure...

Superconducting systems of advanced sources of electrical energy in the USSR

International Nuclear Information System (INIS)

Demirchian, K.S.

1987-01-01

Two examples illustrating some of the possible applications of the superconductivity effect are discussed in this presentation. One of these examples, the MHD method of energy conversion, illustrates the use of superconducting magnet systems for raising the efficiency of conversion of organic fuel energy to electrical energy. The other example, the magnet system of Tokamak-type fusion facility, illustrates the use of superconductivity in application to new sources of energy. The choice of these examples is governed by the fact that the availability of superconducting systems is essential in both cases. Furthermore, the development of such systems per se presents a major scientific and technical achievement based on extensive studies in the field of solid state physics, electro- and thermophysics and engineering

Superconducting Magnetic Energy Storage (SMES). (Latest citations from the NTIS bibliographic database). Published Search

International Nuclear Information System (INIS)

1993-11-01

The bibliography contains citations concerning the technology and use of superconducting magnetic energy storage (SMES). The design, analysis, evaluation, and operation of SMES systems and equipment are discussed. Topics include utility scale SMES plants, SMES for transmission line stabilization, design and protection of superconducting magnets and coils, computer controlled SMES systems, and fusion power reactors. (Contains a minimum of 82 citations and includes a subject term index and title list.)

Superconducting Magnetic Energy Storage (SMES). (Latest citations from the NTIS bibliographic database). Published Search

International Nuclear Information System (INIS)

1993-09-01

The bibliography contains citations concerning the technology and use of superconducting magnetic energy storage (SMES). The design, analysis, evaluation, and operation of SMES systems and equipment are discussed. Topics include utility scale SMES plants, SMES for transmission line stabilization, design and protection of superconducting magnets and coils, computer controlled SMES systems, and fusion power reactors. (Contains a minimum of 82 citations and includes a subject term index and title list.)

Solving LFC problem in an interconnected power system using superconducting magnetic energy storage

Energy Technology Data Exchange (ETDEWEB)

Farahani, Mohsen, E-mail: mhs.farahani@gmail.com [Sama Technical and Vocational Training College, Islamic Azad University, Karaj Branch, Karaj (Iran, Islamic Republic of); Ganjefar, Soheil [Department of Electrical Engineering, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of)

2013-04-15

Highlights: ► Load frequency control of PID type is combined with a SMES. ► Damping speed of frequency and tie-line power flow deviations are considerably increased. ► Optimal parameters of PID and SMES control loop are obtained by PS optimization. -- Abstract: This paper proposes the combination of a load frequency control (LFC) with superconducting magnetic energy storage (SMES) to solve the LFC problem in interconnected power systems. By using this combination, the speed damping of frequency and tie-line power flow deviations is considerably increased. A new control strategy of SMES is proposed in this paper. The problem of determining optimal parameters of PID and SMES control loop is considered as an optimization problem and a pattern search algorithm (PS) optimization is employed to solve it. The simulation results show that if an SMES unit is installed in an interconnected power system, in addition to eliminating oscillations and deviations, the settling time in the frequency and tie-line power flow responses is considerably reduced.

Solving LFC problem in an interconnected power system using superconducting magnetic energy storage

International Nuclear Information System (INIS)

Farahani, Mohsen; Ganjefar, Soheil

2013-01-01

Highlights: ► Load frequency control of PID type is combined with a SMES. ► Damping speed of frequency and tie-line power flow deviations are considerably increased. ► Optimal parameters of PID and SMES control loop are obtained by PS optimization. -- Abstract: This paper proposes the combination of a load frequency control (LFC) with superconducting magnetic energy storage (SMES) to solve the LFC problem in interconnected power systems. By using this combination, the speed damping of frequency and tie-line power flow deviations is considerably increased. A new control strategy of SMES is proposed in this paper. The problem of determining optimal parameters of PID and SMES control loop is considered as an optimization problem and a pattern search algorithm (PS) optimization is employed to solve it. The simulation results show that if an SMES unit is installed in an interconnected power system, in addition to eliminating oscillations and deviations, the settling time in the frequency and tie-line power flow responses is considerably reduced

Energy transport in cooling device by magnetic fluid

Energy Technology Data Exchange (ETDEWEB)

Yamaguchi, Hiroshi, E-mail: hyamaguc@mail.doshisha.ac.jp [Department of Mechanical Engineering, Doshisha University, Kyo-tanabe, Kyoto 610-0321 (Japan); Iwamoto, Yuhiro [Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555 (Japan)

2017-06-01

Temperature sensitive magnetic fluid has a great potential with high performance heat transport ability as well as long distance energy (heat) transporting. In the present study experimental set-up was newly designed and constructed in order to measure basic heat transport characteristics under various magnetic field conditions. Angular dependence for the device (heat transfer section) was also taken into consideration for a sake of practical applications. The energy transfer characteristic (heat transport capability) in the magnetically-driven heat transport (cooling) device using the binary TSMF was fully investigated with the set-up. The obtained results indicate that boiling of the organic mixture (before the magnetic fluid itself reaching boiling point) effectively enhances the heat transfer as well as boosting the flow to circulate in the closed loop by itself. A long-distance heat transport of 5 m is experimentally confirmed, transferring the thermal energy of 35.8 W, even when the device (circulation loop) is horizontally placed. The highlighted results reveal that the proposed cooling device is innovative in a sense of transporting substantial amount of thermal energy (heat) as well as a long distance heat transport. The development of the magnetically-driven heat transport device has a great potential to be replaced for the conventional heat pipe in application of thermal engineering. - Highlights: • Temperature-sensitive magnetic fluid (TSMF) has a great heat transport ability. • Magnetically-driven heat transport device using binary TSMF is proposed. • The basic heat transport characteristics are investigated. • Boiling of the organic mixture effectively enhances the heat transfer. • A long-distance heat transport of 5 m is experimentally confirmed.

Energy transport in cooling device by magnetic fluid

International Nuclear Information System (INIS)

Yamaguchi, Hiroshi; Iwamoto, Yuhiro

2017-01-01

Temperature sensitive magnetic fluid has a great potential with high performance heat transport ability as well as long distance energy (heat) transporting. In the present study experimental set-up was newly designed and constructed in order to measure basic heat transport characteristics under various magnetic field conditions. Angular dependence for the device (heat transfer section) was also taken into consideration for a sake of practical applications. The energy transfer characteristic (heat transport capability) in the magnetically-driven heat transport (cooling) device using the binary TSMF was fully investigated with the set-up. The obtained results indicate that boiling of the organic mixture (before the magnetic fluid itself reaching boiling point) effectively enhances the heat transfer as well as boosting the flow to circulate in the closed loop by itself. A long-distance heat transport of 5 m is experimentally confirmed, transferring the thermal energy of 35.8 W, even when the device (circulation loop) is horizontally placed. The highlighted results reveal that the proposed cooling device is innovative in a sense of transporting substantial amount of thermal energy (heat) as well as a long distance heat transport. The development of the magnetically-driven heat transport device has a great potential to be replaced for the conventional heat pipe in application of thermal engineering. - Highlights: • Temperature-sensitive magnetic fluid (TSMF) has a great heat transport ability. • Magnetically-driven heat transport device using binary TSMF is proposed. • The basic heat transport characteristics are investigated. • Boiling of the organic mixture effectively enhances the heat transfer. • A long-distance heat transport of 5 m is experimentally confirmed.

Magnetic energy dissipation in force-free jets

Science.gov (United States)

Choudhuri, Arnab Rai; Konigl, Arieh

1986-01-01

It is shown that a magnetic pressure-dominated, supersonic jet which expands or contracts in response to variations in the confining external pressure can dissipate magnetic energy through field-line reconnection as it relaxes to a minimum-energy configuration. In order for a continuous dissipation to occur, the effective reconnection time must be a fraction of the expansion time. The dissipation rate for the axisymmetric minimum-energy field configuration is analytically derived. The results indicate that the field relaxation process could be a viable mechanism for powering the synchrotron emission in extragalactic jets if the reconnection time is substantially shorter than the nominal resistive tearing time in the jet.

Global energetics of solar flares. I. Magnetic energies

Energy Technology Data Exchange (ETDEWEB)

Aschwanden, Markus J. [Lockheed Martin, Solar and Astrophysics Laboratory, Org. A021S, Bldg. 252, 3251 Hanover Street, Palo Alto, CA 94304 (United States); Xu, Yan; Jing, Ju, E-mail: aschwanden@lmsal.com, E-mail: yan.xu@njit.edu, E-mail: ju.jing@njit.edu [Space Weather Research Laboratory, Center for Solar-Terrestrial Research, New Jersey Institute of Technology, 323 Martin Luther King Boulevard, Newark, NJ 07102-1982 (United States)

2014-12-10

We present the first part of a project on the global energetics of solar flares and coronal mass ejections that includes about 400 M- and X-class flares observed with Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO). We calculate the potential (E{sub p} ), the nonpotential (E {sub np}) or free energies (E {sub free} = E {sub np} – E{sub p} ), and the flare-dissipated magnetic energies (E {sub diss}). We calculate these magnetic parameters using two different NLFFF codes: the COR-NLFFF code uses the line-of-sight magnetic field component B{sub z} from HMI to define the potential field, and the two-dimensional (2D) coordinates of automatically detected coronal loops in six coronal wavelengths from AIA to measure the helical twist of coronal loops caused by vertical currents, while the PHOT-NLFFF code extrapolates the photospheric three-dimensional (3D) vector fields. We find agreement between the two codes in the measurement of free energies and dissipated energies within a factor of ≲ 3. The size distributions of magnetic parameters exhibit powerlaw slopes that are approximately consistent with the fractal-diffusive self-organized criticality model. The magnetic parameters exhibit scaling laws for the nonpotential energy, E{sub np}∝E{sub p}{sup 1.02}, for the free energy, E{sub free}∝E{sub p}{sup 1.7} and E{sub free}∝B{sub φ}{sup 1.0}L{sup 1.5}, for the dissipated energy, E{sub diss}∝E{sub p}{sup 1.6} and E{sub diss}∝E{sub free}{sup 0.9}, and the energy dissipation volume, V∝E{sub diss}{sup 1.2}. The potential energies vary in the range of E{sub p} = 1 × 10{sup 31}-4 × 10{sup 33} erg, while the free energy has a ratio of E {sub free}/E{sub p} ≈ 1%-25%. The Poynting flux amounts to F {sub flare} ≈ 5 × 10{sup 8}-10{sup 10} erg cm{sup –2} s{sup –1} during flares, which averages to F {sub AR} ≈ 6 × 10{sup 6} erg cm{sup –2} s{sup –1} during the entire observation

A Novel Maximum Power Point Tracking Control for Permanent Magnet Direct Drive Wind Energy Conversion Systems

Directory of Open Access Journals (Sweden)

Wei Wang

2012-05-01

Full Text Available This paper proposes a novel optimal current given (OCG maximum power point tracking (MPPT control strategy based on the theory of power feedback and hill climb searching (HCS for a permanent magnet direct drive wind energy conversion system (WECS. The presented strategy not only has the advantages of not needing the wind speed and wind turbine characteristics of the traditional HCS method, but it also improves the stability and accuracy of MPPT by estimating the exact loss torque. The OCG MPPT control strategy is first carried out by simulation, then an experimental platform based on the dSPACE1103 controller is built and a 5.5 kW permanent magnet synchronous generator (PMSG is tested. Furthermore, the proposed method is compared experimentally with the traditional optimum tip speed ratio (TSR MPPT control. The experiments verify the effectiveness of the proposed OCG MPPT strategy and demonstrate its better performance than the traditional TSR MPPT control.

SSCL magnet systems quality program implementation for laboratory and industry

International Nuclear Information System (INIS)

Warner, D.G.; Bever, D.L.

1992-01-01

The development and delivery of reliable and producible magnets for the Superconducting Super Collider Laboratory (SSCL) require the teamwork of a large and diverse workforce composed of personnel with backgrounds in laboratory research, defense, and energy. The SSCL Magnet Quality Program is being implemented with focus on three definitive objectives: (1) communication of requirements, (2) teamwork, and (3) verification. Examination of the SSCL Magnet Systems Division's (MSD) current and planned approach to implementation of the SSCL Magnet Quality Program utilizing these objectives is discussed

Alpha Channeling in Open-System Magnetic Devices

International Nuclear Information System (INIS)

Fisch, Nathaniel

2016-01-01

The Grant DE-SC0000736, Alpha Channeling in Open-System Magnetic Devices, is a continuation of the Grant DE-FG02-06ER54851, Alpha Channeling in Mirror Machines. In publications funded by DE-SC0000736, the grant DE-FG02-06ER54851 was actually credited. The key results obtained under Grant DE-SC0000736, Alpha Channeling in Open-System Magnetic Devices, appear in a series of publications. The earlier effort under DE-FG02- 06ER54851 was the subject of a previous Final Report. The theme of this later effort has been unusual confinement effects, or de-confinement effects, in open-field magnetic confinement devices. First, the possibilities in losing axisymmetry were explored. Then a number of issues in rotating plasma were addressed. Most importantly, a spinoff application to plasma separations was recognized, which also resulted in a provisional patent application. (That provisional patent application, however, was not pursued further.) Alpha channeling entails injecting waves into magnetically confined plasma to release energy from one particular ion while ejecting that ion. The ejection of the ion is actually a concomitant effect in releasing energy from the ion to the wave. In rotating plasma, there is the opportunity to store the energy in a radial electric field rather than in waves. In other words, the ejected alpha particle loses its energy to the radial potential, which in turn produces plasma rotation. This is a very useful effect, since producing radial electric fields by other means are technologically more difficult. In fact, one can heat ions, and then eject them, to produce the desired radial field. In each case, there is a separation effect of different ions, which generalizes the original alpha-channeling concept of separating alpha ash from hydrogen. In a further generalization of the separation concept, a double-well filter represents a new way to produce high-throughput separations of ions, potentially useful for nuclear waste remediation.

Time-resolved magnetic imaging in an aberration-corrected, energy-filtered photoemission electron microscope

International Nuclear Information System (INIS)

Nickel, F.; Gottlob, D.M.; Krug, I.P.; Doganay, H.; Cramm, S.; Kaiser, A.M.; Lin, G.; Makarov, D.; Schmidt, O.G.

2013-01-01

We report on the implementation and usage of a synchrotron-based time-resolving operation mode in an aberration-corrected, energy-filtered photoemission electron microscope. The setup consists of a new type of sample holder, which enables fast magnetization reversal of the sample by sub-ns pulses of up to 10 mT. Within the sample holder current pulses are generated by a fast avalanche photo diode and transformed into magnetic fields by means of a microstrip line. For more efficient use of the synchrotron time structure, we developed an electrostatic deflection gating mechanism capable of beam blanking within a few nanoseconds. This allows us to operate the setup in the hybrid bunch mode of the storage ring facility, selecting one or several bright singular light pulses which are temporally well-separated from the normal high-intensity multibunch pulse pattern. - Highlights: • A new time-resolving operation mode in photoemission electron microscopy is shown. • Our setup works within an energy-filtered, aberration-corrected PEEM. • A new gating system for bunch selection using synchrotron radiation is developed. • An alternative magnetic excitation system is developed. • First tr-imaging using an energy-filtered, aberration-corrected PEEM is shown

Structure and magnetic field of periodic permanent magnetic focusing system with open magnetic rings

International Nuclear Information System (INIS)

Peng Long; Li Lezhong; Yang Dingyu; Zhu Xinghua; Li Yuanxun

2011-01-01

The magnetic field along the central axis for an axially magnetized permanent magnetic ring was investigated by analytical and finite element methods. For open magnetic rings, both calculated and measured results show that the existence of the radial magnetic field creates a remarkable cosine distribution field along the central axis. A new structure of periodic permanent magnet focusing system with open magnetic rings is proposed. The structure provides a satisfactory magnetic field with a stable peak value of 120 mT for a traveling wave tube system. - Research highlights: → For open magnetic rings, both calculated and measured results show that the existence of the radial magnetic field creates a remarkable cosine distribution field along the central axis. → A new structure of periodic permanent magnet (PPM) focusing system with open magnetic rings is proposed. → The new PPM focusing system with open magnetic rings meets the requirements for TWT system.

Power and reactive power simultaneous control by 0.5 MJ superconducting magnet energy storage

International Nuclear Information System (INIS)

Ise, Toshifumi; Tsuji, Kiichiro; Murakami, Yoshishige

1984-01-01

Superconducting magnet energy storage (SMES) is expected to be widely applied to the pulsed sources for fusion reactor research and to the energy storage substituting for pumping-up power stations, because of its fast energy storing and discharging and very high efficiency. Some results have been obtained so far. In this paper, however, the simultaneous control of power and reactive power is considered for an energy storage composed of two sets of thyristorized power conversion system and superconducting magnets in series connection, and a direct digital control system is described on the principle, design and configuration including the compensator, and on the experiment using the 0.5 MJ superconducting magnet energy storage installed in the Superconduction Engineering Experiment Center, Osaka University. The results obtained are as follows: (1) P control priority mode and Q control priority mode (in which power and reactive power control has priority, respectively) were proposed as the countermeasures when the simultaneous control of power and reactive power became impossible; (2) the design method was established, by which power and reactive power control loops can independently be designed as a result of simulation; (3) the achievement of the simultaneous control of power and reactive power was confirmed by using P-control priority mode and Q-control priority mode, in the experiment using the control system designed by simulation. The validity of simulation model was also confirmed by actual response waveforms. (Wakatsuki, Y.)

Neutron Scattering studies of magnetic molecular magnets

International Nuclear Information System (INIS)

Chaboussant, G.

2009-01-01

This work deals with inelastic neutron scattering studies of magnetic molecular magnets and focuses on their magnetic properties at low temperature and low energies. Several molecular magnets (Mn 12 , V 15 , Ni 12 , Mn 4 , etc.) are reviewed. Inelastic neutron scattering is shown to be a perfectly suited spectroscopy tool to -a) probe magnetic energy levels in such systems and -b) provide key information to understand the quantum tunnel effect of the magnetization in molecular spin clusters. (author)

The power processor of a high temperature superconducting energy storage system

Energy Technology Data Exchange (ETDEWEB)

Ollila, J. [Power Electronics, Tampere University of Technology, Tampere (Finland)

1997-12-31

This report introduces the structure and properties of a power processor unit for a high temperature superconducting magnetic energy storage system which is bused in an UPS demonstration application. The operation is first demonstrated using simulations. The software based operating and control system utilising combined Delta-Sigma and Sliding-Mode control is described shortly. Preliminary test results using a conventional NbTi superconducting energy y storage magnet operating at 4.2 K is shown. (orig.)

Energy released by the interaction of coronal magnetic fields

International Nuclear Information System (INIS)

Sheeley, N.R. Jr.

1976-01-01

Comparisons between coronal spectroheliograms and photospheric magnetograms are presented to support the idea that as coronal magnetic fields interact, a process of field line reconnection usually takes place as a natural way of preventing magnetic stresses from building up in the lower corona. This suggests that the energy which would have been stored in stressed fields in continuously released as kinetic energy of material being driven aside to make way for the reconnecting fields. However, this kinetic energy is negligible compared to the thermal energy of the coronal plasma. Therefore, it appears that these slow adjustments of coronal magnetic fields cannot account for even the normal heating of the corona, much less the energetic events associated with solar flares. (Auth.)

Remote monitoring system for the cryogenic system of superconducting magnets in the SuperKEKB interaction region

Science.gov (United States)

Aoki, K.; Ohuchi, N.; Zong, Z.; Arimoto, Y.; Wang, X.; Yamaoka, H.; Kawai, M.; Kondou, Y.; Makida, Y.; Hirose, M.; Endou, T.; Iwasaki, M.; Nakamura, T.

2017-12-01

A remote monitoring system was developed based on the software infrastructure of the Experimental Physics and Industrial Control System (EPICS) for the cryogenic system of superconducting magnets in the interaction region of the SuperKEKB accelerator. The SuperKEKB has been constructed to conduct high-energy physics experiments at KEK. These superconducting magnets consist of three apparatuses, the Belle II detector solenoid, and QCSL and QCSR accelerator magnets. They are each contained in three cryostats cooled by dedicated helium cryogenic systems. The monitoring system was developed to read data of the EX-8000, which is an integrated instrumentation system to control all cryogenic components. The monitoring system uses the I/O control tools of EPICS software for TCP/IP, archiving techniques using a relational database, and easy human-computer interface. Using this monitoring system, it is possible to remotely monitor all real-time data of the superconducting magnets and cryogenic systems. It is also convenient to share data among multiple groups.

Study on frequency characteristics of wireless power transmission system based on magnetic coupling resonance

Science.gov (United States)

Liang, L. H.; Liu, Z. Z.; Hou, Y. J.; Zeng, H.; Yue, Z. K.; Cui, S.

2017-11-01

In order to study the frequency characteristics of the wireless energy transmission system based on the magnetic coupling resonance, a circuit model based on the magnetic coupling resonant wireless energy transmission system is established. The influence of the load on the frequency characteristics of the wireless power transmission system is analysed. The circuit coupling theory is used to derive the minimum load required to suppress frequency splitting. Simulation and experimental results verify that when the load size is lower than a certain value, the system will appear frequency splitting, increasing the load size can effectively suppress the frequency splitting phenomenon. The power regulation scheme of the wireless charging system based on magnetic coupling resonance is given. This study provides a theoretical basis for load selection and power regulation of wireless power transmission systems.

Sustained turbulence and magnetic energy in non-rotating shear flows

DEFF Research Database (Denmark)

Nauman, Farrukh; Blackman, Eric G.

2017-01-01

From numerical simulations, we show that non-rotating magnetohydrodynamic shear flows are unstable to finite amplitude velocity perturbations and become turbulent, leading to the growth and sustenance of magnetic energy, including large scale fields. This supports the concept that sustained...... magnetic energy from turbulence is independent of the driving mechanism for large enough magnetic Reynolds numbers....

Energy minibands degeneration induced by magnetic field effects in graphene superlattices

Science.gov (United States)

Reyes-Villagrana, R. A.; Carrera-Escobedo, V. H.; Suárez-López, J. R.; Madrigal-Melchor, J.; Rodríguez-Vargas, I.

2017-12-01

Energy minibands are a basic feature of practically any superlattice. In this regard graphene superlattices are not the exception and recently miniband transport has been reported through magneto-transport measurements. In this work, we compute the energy miniband and transport characteristics for graphene superlattices in which the energy barriers are generated by magnetic and electric fields. The transfer matrix approach and the Landauer-Büttiker formalism have been implemented to calculate the energy minibands and the linear-regime conductance. We find that energy minibands are very sensitive to the magnetic field and become degenerate by rising it. We were also able to correlate the evolution of the energy minibands as a function of the magnetic field with the transport characteristics, finding that miniband transport can be destroyed by magnetic field effects. Here, it is important to remark that although magnetic field effects have been a key element to unveil miniband transport, they can also destroy it.

Endogenous magnetic reconnection and associated high energy plasma processes

Science.gov (United States)

Coppi, B.; Basu, B.

2018-02-01

An endogenous reconnection process involves a driving factor that lays inside the layer where a drastic change of magnetic field topology occurs. A process of this kind is shown to take place when an electron temperature gradient is present in a magnetically confined plasma and the evolving electron temperature fluctuations are anisotropic. The width of the reconnecting layer remains significant even when large macroscopic distances are considered. In view of the fact that there are plasmas in the Universe with considerable electron thermal energy contents this feature can be relied upon in order to produce generation or conversion of magnetic energy, high energy particle populations and momentum and angular momentum transport.

Equilibrium magnetization and microstructure of the system of superparamagnetic interacting particles: numerical simulation

CERN Document Server

Pshenichnikov, A F

2000-01-01

The Monte Carlo method is used to study the equilibrium magnetization of a 3D system of superparamagnetic particles taking into account the steric and dipole-dipole interparticle interactions. Two types of systems are considered: magnetic fluids and solidified ferrocolloids containing randomly spatially distributed particles with negligible energy of magnetic anisotropy. The results of numerical simulations confirm the universality of Langevin susceptibility as a main dimensionless parameter determining the influence of interparticle interactions on the magnetization of the system for moderate values of the aggregation parameter. The obtained results are in good agreement with theoretical and experimental data. At large values of the aggregation parameter, the clustering of particles in magnetic fluids is observed resulting in a reduction of their magnetization as compared to solidified systems. It is shown that the magnetization of solidified systems can be well described by the modified effective field appr...

Energy Recovery from a Non-Linear Electromagnetic System

Directory of Open Access Journals (Sweden)

Kęcik Krzysztof

2018-03-01

Full Text Available The paper presents study of a pseudo-magnetic levitation system (pseudo-maglev dedicated for energy harvesting. The idea rely on motion of a pseudo-levitating magnet in a coil’s terminal. The study based on real prototype harvester system, which in the pendulum dynamic vibration absorber is applied. For some parameters, the stability loss caused by the period doubling bifurcation is detected. The coexistence of two stable solutions, one of which is much better for energy harvesting is observed. The influence of the pseudo-maglev parameters on the recovered current and stability of the periodic solutions is presented in detail. The obtained results show, that the best energy recovery occurs for the high pseudo-maglev stiffness and close to the coil resistance. The amplitude’s excitation, the load resistances and the coupling coefficient strongly influence on the system’s response.

Design and simulation of permanent magnet synchronous motor control system

Science.gov (United States)

Li, Li; Liu, Yongqiu

2018-06-01

In recent years, with the development of power electronics, microelectronics, new motor control theory and rare earth permanent magnet materials, permanent magnet synchronous motors have been rapidly applied. Permanent magnet synchronous motors have the advantages of small size, low loss and high efficiency. Today, energy conservation and environmental protection are increasingly valued. It is very necessary to study them. Permanent magnet synchronous motor control system has a wide range of application prospects in the fields of electric vehicles, ships and other transportation. Using the simulation function of MATLAB/SIMULINK, a modular design structure was used to simulate the whole system model of speed loop adjustment, current PI modulation, SVPWM (Space Vector Pulse Width Module) wave generation and double closed loop. The results show that this control method has good robustness, and this method can improve the design efficiency and shorten the system design time. In this article, the analysis of the control principle of modern permanent magnet synchronous motor and the various processes of MATLAB simulation application will be analyzed in detail. The basic theory, basic method and application technology of the permanent magnet synchronous motor control system are systematically introduced.

Results of the studies on energy deposition in IR6 superconducting magnets from continuous beam loss on the TCDQ system

CERN Document Server

Bracco, C; Presland, A; Redaelli, S; Sarchiapone, L; Weiler, T

2007-01-01

A single sided mobile graphite diluter block TCDQ, in combination with a two-sided secondary collimator TCS and an iron shield TCDQM, will be installed in front of the superconducting quadrupole Q4 magnets in IR6, in order to protect it and other downstream LHC machine elements from destruction in the event of a beam dump that is not synchronised with the abort gap. The TCDQ will be positioned close to the beam, and will intercept the particles from the secondary halo during low beam lifetime. Previous studies (1-4) have shown that the energy deposited in the Q4 magnet coils can be close to or above the quench limit. In this note the results of the latest FLUKA energy deposition simulations for Beam 2 are described, including an upgrade possibility for the TCDQ system with an additional shielding device. The results are discussed in the context of the expected performance levels for the different phases of LHC operation.

Basic study on an energy conversion system using boiling two-phase flows of temperature-sensitive magnetic fluid. Theoretical analysis based on thermal nonequilibrium model and flow visualization using ultrasonic echo

International Nuclear Information System (INIS)

Ishimoto, Jun; Kamiyama, Shinichi; Okubo, Masaaki.

1995-01-01

Effects of magnetic field on the characteristics of boiling two-phase pipe flow of temperature-sensitive magnetic fluid are clarified in detail both theoretically and experimentally. Firstly, governing equations of two-phase magnetic fluid flow based on the thermal nonequilibrium two-fluid model are presented and numerically solved considering evaporation and condensation between gas- and liquid-phases. Next, behaviour of vapor bubbles is visualized with ultrasonic echo in the region of nonuniform magnetic field. This is recorded and processed with an image processor. As a result, the distributions of void fraction in the two-phase flow are obtained. Furthermore, detailed characteristics of the two-phase magnetic fluid flow are investigated using a small test loop of the new energy conversion system. From the numerical and experimental results, it is known that the precise control of the boiling two-phase flow and bubble generation is possible by using the nonuniform magnetic field effectively. These fundamental studies on the characteristics of two-phase magnetic fluid flow will contribute to the development of the new energy conversion system using a gas-liquid boiling two-phase flow of magnetic fluid. (author)

Magnetic Fusion Energy Technology Fellowship Program: Summary of program activities for calendar year 1985

International Nuclear Information System (INIS)

1985-01-01

This report summarizes the activities of the US Department of Energy (DOE) Magnetic Fusion Energy Technology Fellowship program (MFETF) for the 1985 calendar year. The MFETF program has continued to support the mission of the Office of Fusion Energy (OFE) and its Division of Development and Technology (DDT) by ensuring the availability of appropriately trained engineering manpower needed to implement the OFE/DDT magnetic fusion energy agenda. This program provides training and research opportunities to highly qualified students at DOE-designated academic, private sector, and government magnetic fusion energy institutions. The objectives of the Magnetic Fusion Energy Technology Fellowship program are: (1) to provide support for graduate study, training, and research in magnetic fusion energy technology; (2) to ensure an adequate supply of appropriately trained manpower to implement the nation's magnetic fusion energy agenda; (3) to raise the visibility of careers in magnetic fusion energy technology and to encourage students to pursue such careers; and (4) to make national magnetic fusion energy facilities available for manpower training

Maximum field capability of energy saver superconducting magnets

International Nuclear Information System (INIS)

Turkot, F.; Cooper, W.E.; Hanft, R.; McInturff, A.

1983-01-01

At an energy of 1 TeV the superconducting cable in the Energy Saver dipole magnets will be operating at ca. 96% of its nominal short sample limit; the corresponding number in the quadrupole magnets will be 81%. All magnets for the Saver are individually tested for maximum current capability under two modes of operation; some 900 dipoles and 275 quadrupoles have now been measured. The dipole winding is composed of four individually wound coils which in general come from four different reels of cable. As part of the magnet fabrication quality control a short piece of cable from both ends of each reel has its critical current measured at 5T and 4.3K. In this paper the authors describe and present the statistical results of the maximum field tests (including quench and cycle) on Saver dipole and quadrupole magnets and explore the correlation of these tests with cable critical current

Measurement of magnetic fluctuation induced energy transport

International Nuclear Information System (INIS)

Fiksel, G.; Prager, S.C.; Shen, W.; Stoneking, M.

1993-11-01

The local electron energy flux produced by magnetic fluctuations has been measured directly in the MST reversed field pinch (over the radial range r/a > 0.75). The flux, produced by electrons traveling parallel to a fluctuating magnetic field, is obtained from correlation between the fluctuations in the parallel heat flux and the radial magnetic field. The fluctuation induced flux is large (100 kW/cm 2 ) in the ''core'' (r/a 2 ) in the edge

Rare-earth-free high energy product manganese-based magnetic materials.

Science.gov (United States)

Patel, Ketan; Zhang, Jingming; Ren, Shenqiang

2018-06-14

The constant drive to replace rare-earth metal magnets has initiated great interest in an alternative. Manganese (Mn) has emerged to be a potential candidate as a key element in rare-earth-free magnets. Its five unpaired valence electrons give it a large magnetocrystalline energy and the ability to form several intermetallic compounds. These factors have led Mn-based magnets to be a potential replacement for rare-earth permanent magnets for several applications, such as efficient power electronics, energy generators, magnetic recording and tunneling applications, and spintronics. For past few decades, Mn-based magnets have been explored in many different forms, such as bulk magnets, thin films, and nanoparticles. Here, we review the recent progress in the synthesis and structure-magnetic property relationships of Mn-based rare-earth-free magnets (MnBi, MnAl and MnGa). Furthermore, we discuss their potential to replace rare-earth magnetic materials through the control of their structure and composition to achieve the theoretically predicted magnetic properties.

TMX magnet control system

International Nuclear Information System (INIS)

Goerz, D.A.

1978-01-01

A control system utilizing a microcomputer has been developed that controls the power supplies driving the Tandem Mirror Experiment (TMX) magnet set and monitors magnet coil operation. The magnet set consists of 18 magnet coils that are driven by 26 dc power supplies. There are two possible modes of operation with this system: a pulse mode where the coils are pulsed on for several seconds with a dc power consumption of 16 MW; and a continuous mode where the coils can run steady state at 10 percent of maximum current ratings. The processor has been given an active control role and serves as an interface between the operator and electronic circuitry that controls the magnet power supplies. This microcomputer also collects and processes data from many analog singal monitors in the coil circuits and numerous status signals from the supplies. Placing the microcomputer in an active control role has yielded a compact, cost effective system that simplifies the magnet system operation and has proven to be very reliable. This paper will describe the TMX magnet control sytem and discuss its development

Energy measurement using a resonator based time-of-flight system

International Nuclear Information System (INIS)

Pardo, R.C.; Clifft, B.; Johnson, K.W.; Lewis, R.N.

1983-01-01

A resonant pick-up time-of-flight system has been developed for the precise measurement of beam energy at the Argonne Tandem-Linac Accelerator System (ATLAS). The excellent timing characteristics available with ATLAS beams make it desirable to design the beam transport system to be isochronous. The advantages of the resonant time-of-flight system over other energy analysis systems such as the dispersive magnet system are numerous. The system is non-interceptive and non-destructive and preserves the beam phase space. It is non-dispersive. Path length variations are not introduced into the beam which would reduce the timing resolution. It has a large signal-to-noise ratio when compared to non-resonant beam pick-up techniques. It provides the means to precisely set the linac energy and potentially to control the energy in a feedback loop. Finally, the resonant pick-up time-of-flight system is less expensive than an equivalent magnetic system. It consists of two beam-excited resonators, associated electronics to decode the information, a computer interface to the linac PDP 11/34 control computer, and software to analyze the information and deduce the measured beam energy. This report describes the system and its components and gives a schematic overview

A chopper circuit for energy transfer between superconducting magnets

International Nuclear Information System (INIS)

Onishi, Toshitada; Tateishi, Hiroshi; Takeda, Masatoshi; Matsuura, Toshiaki; Nakatani, Toshio.

1986-01-01

It has been suggested that superconducting magnets could provide a medium for storing energy and supplying the large energy pulses needed by experimental nuclear-fusion equipment and similar loads. Based on this concept, tests on energy transfer between superconducting magnets are currently being conducted at the Agency of Industrial Science and Technology's Electrotechnical Laboratory. Mitsubishi Electric has pioneered the world's first chopper circuit for this application. The circuit has the advantages of being simple and permitting high-speed, bipolar energy transfer. The article describes this circuit and its testing. (author)

Energy distribution of a magnetic stringy black hole

International Nuclear Information System (INIS)

Radinschi, Irina

2004-01-01

In this paper we calculate the energy distribution of a magnetic stringy black hole solution in the Landau and Lifshitz and Weinberg prescriptions. It is well-known that a main property of the low energy theory is that there are two different frames in which the features of the space-time may look very different. These two frames are the Einstein frame and the string frame. We choose the string frame to carry out the calculations. We study the dependence of the energy associated with the magnetic stringy black hole solution on its mass M and charge Q. (authors)

Magnetization reversal processes of single nanomagnets and their energy barrier

International Nuclear Information System (INIS)

Krone, P.; Makarov, D.; Albrecht, M.; Schrefl, T.; Suess, D.

2010-01-01

Micromagnetic simulations were performed to investigate the influence of geometry and magnetic anisotropy constant on energy barrier and magnetization reversal mechanism of individual bits important for the bit patterned media concept in magnetic data storage. It is shown that dependency of the energy barrier on magnetic and geometric properties of bits can be described by an analytical approach in the case of quasi-coherent magnetization rotation process. However, when the bit size exceeds a critical size, for which an incoherent magnetization reversal is preferred, the analytical approach becomes invalid and no self-consistent theory is available. By systematically investigating the influence of bit size on the magnetization reversal mode, it was found that the transition from quasi-coherent to incoherent magnetization reversal mode can still be described analytically if an activation volume is considered instead of the bit volume. In this case, the nucleation volume is an important parameter determining thermal stability of the bit. If the volume of the bit is larger than twice the activation volume, the energy barrier stays nearly constant; with further increase in bit size, no gain in thermal stability can be achieved.

MAGNETIC ENERGY SPECTRA IN SOLAR ACTIVE REGIONS

International Nuclear Information System (INIS)

Abramenko, Valentyna; Yurchyshyn, Vasyl

2010-01-01

Line-of-sight magnetograms for 217 active regions (ARs) with different flare rates observed at the solar disk center from 1997 January until 2006 December are utilized to study the turbulence regime and its relationship to flare productivity. Data from the SOHO/MDI instrument recorded in the high-resolution mode and data from the BBSO magnetograph were used. The turbulence regime was probed via magnetic energy spectra and magnetic dissipation spectra. We found steeper energy spectra for ARs with higher flare productivity. We also report that both the power index, α, of the energy spectrum, E(k) ∼ k -α , and the total spectral energy, W = ∫E(k)dk, are comparably correlated with the flare index, A, of an AR. The correlations are found to be stronger than those found between the flare index and the total unsigned flux. The flare index for an AR can be estimated based on measurements of α and W as A = 10 b (αW) c , with b = -7.92 ± 0.58 and c = 1.85 ± 0.13. We found that the regime of the fully developed turbulence occurs in decaying ARs and in emerging ARs (at the very early stage of emergence). Well-developed ARs display underdeveloped turbulence with strong magnetic dissipation at all scales.

Optimization of the protective energy removal parameters for tokamak HT7-U superconducting magnets

Energy Technology Data Exchange (ETDEWEB)

Khvostenko, P.P.; Chudnovsky, A.N.; Posadsky, I.A. [RRC ' Kurchatov Inst.' , Nuclear Fusion Inst., Moscow (Russian Federation); Bi, Y.F.; Cheng, S.M.; He, Y.X. [Academia Sinica, Hefei, Anhui (China). Inst. of Plasma Physics

1998-07-01

The design of the HT-7U superconducting tokamak is in progress now. The design incorporates superconducting magnets of the toroidal field and poloidal field systems. Toroidal field system consists of 16 D-shape coils and poloidal field system consists of 12 coils. All coils will be use NbTi/Cu cable-in-conduit conductor cooled with forced-flow supercritical helium at 4.5 K, 4 Bar. Quench in the superconducting magnets is accompanied byconversion of the stored magnetic field energy into a thermal one which is spent on heating of both the coil part which made transition into a normal state and dump resistors. A non-uniform heating of the coil part results in the emergence of thermomechanical stresses which can cause its destruction. The protective removal of a current is realized to prevent the coil destruction at the emergence of the quench. In that case, the faster the current removal occurs, the less the coil heating is. On the other hand, the current removal rate should not be too high in order to avoid an electric breakdown by the excited inductive voltage. Optimization of the protective energy removal parameters both for TF and PF superconducting magnets is presented. (author)

Optimization of the protective energy removal parameters for tokamak HT7-U superconducting magnets

International Nuclear Information System (INIS)

Khvostenko, P.P.; Chudnovsky, A.N.; Posadsky, I.A.; Bi, Y.F.; Cheng, S.M.; He, Y.X.

1998-01-01

The design of the HT-7U superconducting tokamak is in progress now. The design incorporates superconducting magnets of the toroidal field and poloidal field systems. Toroidal field system consists of 16 D-shape coils and poloidal field system consists of 12 coils. All coils will be use NbTi/Cu cable-in-conduit conductor cooled with forced-flow supercritical helium at 4.5 K, 4 Bar. Quench in the superconducting magnets is accompanied by conversion of the stored magnetic field energy into a thermal one which is spent on heating of both the coil part which made transition into a normal state and dump resistors. A non-uniform heating of the coil part results in the emergence of thermomechanical stresses which can cause its destruction. The protective removal of a current is realized to prevent the coil destruction at the emergence of the quench. In that case, the faster the current removal occurs, the less the coil heating is. On the other hand, the current removal rate should not be too high in order to avoid an electric breakdown by the excited inductive voltage. Optimization of the protective energy removal parameters both for TF and PF superconducting magnets is presented. (author)

Controlling the competing magnetic anisotropy energies in FineMET amorphous thin films with ultra-soft magnetic properties

Directory of Open Access Journals (Sweden)

Ansar Masood

2017-05-01

Full Text Available Thickness dependent competing magnetic anisotropy energies were investigated to explore the global magnetic behaviours of FineMET amorphous thin films. A dominant perpendicular magnetization component in the as-deposited state of thinner films was observed due to high magnetoelastic anisotropy energy which arises from stresses induced at the substrate-film interface. This perpendicular magnetization component decreases with increasing film thickness. Thermal annealing at elevated temperature revealed a significant influence on the magnetization state of the FineMET thin films and controlled annealing steps leads to ultra-soft magnetic properties, making these thin films alloys ideal for a wide range of applications.

Systems and methods for the magnetic insulation of accelerator electrodes in electrostatic accelerators

Science.gov (United States)

Grisham, Larry R

2013-12-17

The present invention provides systems and methods for the magnetic insulation of accelerator electrodes in electrostatic accelerators. Advantageously, the systems and methods of the present invention improve the practically obtainable performance of these electrostatic accelerators by addressing, among other things, voltage holding problems and conditioning issues. The problems and issues are addressed by flowing electric currents along these accelerator electrodes to produce magnetic fields that envelope the accelerator electrodes and their support structures, so as to prevent very low energy electrons from leaving the surfaces of the accelerator electrodes and subsequently picking up energy from the surrounding electric field. In various applications, this magnetic insulation must only produce modest gains in voltage holding capability to represent a significant achievement.

Equilibrium magnetization and microstructure of the system of superparamagnetic interacting particles: numerical simulation

International Nuclear Information System (INIS)

Pshenichnikov, A.F.; Mekhonoshin, V.V.

2000-01-01

The Monte Carlo method is used to study the equilibrium magnetization of a 3D system of superparamagnetic particles taking into account the steric and dipole-dipole interparticle interactions. Two types of systems are considered: magnetic fluids and solidified ferrocolloids containing randomly spatially distributed particles with negligible energy of magnetic anisotropy. The results of numerical simulations confirm the universality of Langevin susceptibility as a main dimensionless parameter determining the influence of interparticle interactions on the magnetization of the system for moderate values of the aggregation parameter. The obtained results are in good agreement with theoretical and experimental data. At large values of the aggregation parameter, the clustering of particles in magnetic fluids is observed resulting in a reduction of their magnetization as compared to solidified systems. It is shown that the magnetization of solidified systems can be well described by the modified effective field approximation within the whole investigated range of parameters

Permanent magnet electron beam ion source/trap systems with bakeable magnets for improved operation conditions

Energy Technology Data Exchange (ETDEWEB)

Schmidt, M., E-mail: mike.schmidt@dreebit.com [DREEBIT GmbH, 01109 Dresden (Germany); Zschornack, G.; Kentsch, U.; Ritter, E. [Department of Physics, Dresden University of Technology, 01062 Dresden, Germany and Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, 01328 Dresden (Germany)

2014-02-15

The magnetic system of a Dresden electron beam ion source (EBIS) generating the necessary magnetic field with a new type of permanent magnet made of high energy density NdFeB-type material operable at temperatures above 100 °C has been investigated and tested. The employment of such kind of magnets provides simplified operation without the time-consuming installation and de-installation procedures of the magnets for the necessary baking of the ion source after commissioning and maintenance work. Furthermore, with the use of a new magnetization technique the geometrical filling factor of the magnetic Dresden EBIS design could be increased to a filling factor of 100% leading to an axial magnetic field strength of approximately 0.5 T exceeding the old design by 20%. Simulations using the finite element method software Field Precision and their results compared with measurements are presented as well. It could be shown that several baking cycles at temperatures higher than 100 °C did not change the magnetic properties of the setup.

Permanent magnet electron beam ion source/trap systems with bakeable magnets for improved operation conditions.

Science.gov (United States)

Schmidt, M; Zschornack, G; Kentsch, U; Ritter, E

2014-02-01

The magnetic system of a Dresden electron beam ion source (EBIS) generating the necessary magnetic field with a new type of permanent magnet made of high energy density NdFeB-type material operable at temperatures above 100 °C has been investigated and tested. The employment of such kind of magnets provides simplified operation without the time-consuming installation and de-installation procedures of the magnets for the necessary baking of the ion source after commissioning and maintenance work. Furthermore, with the use of a new magnetization technique the geometrical filling factor of the magnetic Dresden EBIS design could be increased to a filling factor of 100% leading to an axial magnetic field strength of approximately 0.5 T exceeding the old design by 20%. Simulations using the finite element method software Field Precision and their results compared with measurements are presented as well. It could be shown that several baking cycles at temperatures higher than 100 °C did not change the magnetic properties of the setup.

Permanent magnet electron beam ion source/trap systems with bakeable magnets for improved operation conditions

International Nuclear Information System (INIS)

Schmidt, M.; Zschornack, G.; Kentsch, U.; Ritter, E.

2014-01-01

The magnetic system of a Dresden electron beam ion source (EBIS) generating the necessary magnetic field with a new type of permanent magnet made of high energy density NdFeB-type material operable at temperatures above 100 °C has been investigated and tested. The employment of such kind of magnets provides simplified operation without the time-consuming installation and de-installation procedures of the magnets for the necessary baking of the ion source after commissioning and maintenance work. Furthermore, with the use of a new magnetization technique the geometrical filling factor of the magnetic Dresden EBIS design could be increased to a filling factor of 100% leading to an axial magnetic field strength of approximately 0.5 T exceeding the old design by 20%. Simulations using the finite element method software Field Precision and their results compared with measurements are presented as well. It could be shown that several baking cycles at temperatures higher than 100 °C did not change the magnetic properties of the setup

Analysis of an HTS coil for large scale superconducting magnetic energy storage

Energy Technology Data Exchange (ETDEWEB)

Lee, Ji Young; Lee, Se Yeon; Choi, Kyeong Dal; Park, Sang Ho; Hong, Gye Won; Kim, Sung Soo; Kim, Woo Seok [Korea Polytechnic University, Siheung (Korea, Republic of); Lee, Ji Kwang [Woosuk University, Wanju (Korea, Republic of)

2015-06-15

It has been well known that a toroid is the inevitable shape for a high temperature superconducting (HTS) coil as a component of a large scale superconducting magnetic energy storage system (SMES) because it is the best option to minimize a magnetic field intensity applied perpendicularly to the HTS wires. Even though a perfect toroid coil does not have a perpendicular magnetic field, for a practical toroid coil composed of many HTS pancake coils, some type of perpendicular magnetic field cannot be avoided, which is a major cause of degradation of the HTS wires. In order to suggest an optimum design solution for an HTS SMES system, we need an accurate, fast, and effective calculation for the magnetic field, mechanical stresses, and stored energy. As a calculation method for these criteria, a numerical calculation such as an finite element method (FEM) has usually been adopted. However, a 3-dimensional FEM can involve complicated calculation and can be relatively time consuming, which leads to very inefficient iterations for an optimal design process. In this paper, we suggested an intuitive and effective way to determine the maximum magnetic field intensity in the HTS coil by using an analytic and statistical calculation method. We were able to achieve a remarkable reduction of the calculation time by using this method. The calculation results using this method for sample model coils were compared with those obtained by conventional numerical method to verify the accuracy and availability of this proposed method. After the successful substitution of this calculation method for the proposed design program, a similar method of determining the maximum mechanical stress in the HTS coil will also be studied as a future work.

Analysis of an HTS coil for large scale superconducting magnetic energy storage

International Nuclear Information System (INIS)

Lee, Ji Young; Lee, Se Yeon; Choi, Kyeong Dal; Park, Sang Ho; Hong, Gye Won; Kim, Sung Soo; Kim, Woo Seok; Lee, Ji Kwang

2015-01-01

It has been well known that a toroid is the inevitable shape for a high temperature superconducting (HTS) coil as a component of a large scale superconducting magnetic energy storage system (SMES) because it is the best option to minimize a magnetic field intensity applied perpendicularly to the HTS wires. Even though a perfect toroid coil does not have a perpendicular magnetic field, for a practical toroid coil composed of many HTS pancake coils, some type of perpendicular magnetic field cannot be avoided, which is a major cause of degradation of the HTS wires. In order to suggest an optimum design solution for an HTS SMES system, we need an accurate, fast, and effective calculation for the magnetic field, mechanical stresses, and stored energy. As a calculation method for these criteria, a numerical calculation such as an finite element method (FEM) has usually been adopted. However, a 3-dimensional FEM can involve complicated calculation and can be relatively time consuming, which leads to very inefficient iterations for an optimal design process. In this paper, we suggested an intuitive and effective way to determine the maximum magnetic field intensity in the HTS coil by using an analytic and statistical calculation method. We were able to achieve a remarkable reduction of the calculation time by using this method. The calculation results using this method for sample model coils were compared with those obtained by conventional numerical method to verify the accuracy and availability of this proposed method. After the successful substitution of this calculation method for the proposed design program, a similar method of determining the maximum mechanical stress in the HTS coil will also be studied as a future work

Role of supercomputers in magnetic fusion and energy research programs

International Nuclear Information System (INIS)

Killeen, J.

1985-06-01

The importance of computer modeling in magnetic fusion (MFE) and energy research (ER) programs is discussed. The need for the most advanced supercomputers is described, and the role of the National Magnetic Fusion Energy Computer Center in meeting these needs is explained

Neutral-beam systems for magnetic-fusion reactors

International Nuclear Information System (INIS)

Fink, J.H.

1981-01-01

Neutral beams for magnetic fusion reactors are at an early stage of development, and require considerable effort to make them into the large, reliable, and efficient systems needed for future power plants. To optimize their performance to establish specific goals for component development, systematic analysis of the beamlines is essential. Three ion source characteristics are discussed: arc-cathode life, gas efficiency, and beam divergence, and their significance in a high-energy neutral-beam system is evaluated

Environmental and economic assessments of magnetic and inertial fusion energy reactors

Science.gov (United States)

Yamazaki, K.; Oishi, T.; Mori, K.

2011-10-01

Global warming due to rapid greenhouse gas (GHG) emissions is one of the present-day crucial problems, and fusion reactors are expected to be abundant electric power generation systems to reduce human GHG emission amounts. To search for an environmental-friendly and economical fusion reactor system, comparative system studies have been done for several magnetic fusion energy reactors, and have been extended to include inertial fusion energy reactors. We clarify new scaling formulae for the cost of electricity and GHG emission rate with respect to key design parameters, which might be helpful in making a strategy for fusion research development. Comparisons with other conventional electric power generation systems are carried out taking into account the introduction of GHG taxes and the application of the carbon dioxide capture and storage system to fossil power generators.

Overview of FAR-TECH's magnetic fusion energy research

Science.gov (United States)

Kim, Jin-Soo; Bogatu, I. N.; Galkin, S. A.; Spencer, J. Andrew; Svidzinski, V. A.; Zhao, L.

2017-10-01

FAR-TECH, Inc. has been working on magnetic fusion energy research over two-decades. During the years, we have developed unique approaches to help understanding the physics, and resolving issues in magnetic fusion energy. The specific areas of work have been in modeling RF waves in plasmas, MHD modeling and mode-identification, and nano-particle plasma jet and its application to disruption mitigation. Our research highlights in recent years will be presented with examples, specifically, developments of FullWave (Full Wave RF code), PMARS (Parallelized MARS code), and HEM (Hybrid ElectroMagnetic code). In addition, nano-particle plasma-jet (NPPJ) and its application for disruption mitigation will be presented. Work is supported by the U.S. DOE SBIR program.

Research Needs for Magnetic Fusion Energy Sciences

Energy Technology Data Exchange (ETDEWEB)

Neilson, Hutch

2009-07-01

Nuclear fusion — the process that powers the sun — offers an environmentally benign, intrinsically safe energy source with an abundant supply of low-cost fuel. It is the focus of an international research program, including the ITER fusion collaboration, which involves seven parties representing half the world’s population. The realization of fusion power would change the economics and ecology of energy production as profoundly as petroleum exploitation did two centuries ago. The 21st century finds fusion research in a transformed landscape. The worldwide fusion community broadly agrees that the science has advanced to the point where an aggressive action plan, aimed at the remaining barriers to practical fusion energy, is warranted. At the same time, and largely because of its scientific advance, the program faces new challenges; above all it is challenged to demonstrate the timeliness of its promised benefits. In response to this changed landscape, the Office of Fusion Energy Sciences (OFES) in the US Department of Energy commissioned a number of community-based studies of the key scientific and technical foci of magnetic fusion research. The Research Needs Workshop (ReNeW) for Magnetic Fusion Energy Sciences is a capstone to these studies. In the context of magnetic fusion energy, ReNeW surveyed the issues identified in previous studies, and used them as a starting point to define and characterize the research activities that the advance of fusion as a practical energy source will require. Thus, ReNeW’s task was to identify (1) the scientific and technological research frontiers of the fusion program, and, especially, (2) a set of activities that will most effectively advance those frontiers. (Note that ReNeW was not charged with developing a strategic plan or timeline for the implementation of fusion power.)

Potential energy efficiency and conservation, economic, and environmental benefits from the implementation of superconducting magnetic energy storage

International Nuclear Information System (INIS)

Baumann, P.D.

1992-01-01

This paper reports on Superconducting Magnetic Energy Storage (SMES) which is a recent technology that has the capability to significantly improve electrical system operations within electric utility systems. The technology has already been demonstrated by Bonneville Power Administration in a 30-MJ SMES test demonstration unit. Savings in utility operations from improved system efficiency, increased reliability, and reduced maintenance requirements contribute to the economic justification of SMES. Beyond these benefits, there are additional benefits which in the long run may equal or outweigh the electrical operational benefits. These benefits are the energy conservation and environmental benefits. The technology has the capability of reducing fuel consumption which can in turn reduce emissions. In a regional setting it can shift emissions both in volumes and in physical. With its capability to strategically shift generation and significantly affect emissions and air quality it can stretch clean energy generation options, thus SMES can be seen as an energy and environmental management technology and tool

A novel magnetic lead screw active suspension system for vehicles

DEFF Research Database (Denmark)

Berg, Nick Ilsø; Holm, Rasmus Koldborg; Rasmussen, Peter Omand

2014-01-01

This paper encompasses a detailed study of the redesign of a novel Magnetic Lead Screw (MLS) active suspension system for possible regeneration of the energy dispatched in the suspension system and active control of vehicle body movement. The MLS converts a low speed high force linear motion...... of a translator into a high speed low torque rotational motion of a rotor through helically shaped magnets. The paper describes the drawback of the first MLS prototype v1.0 developed for active suspension system, which lead to a new design of the MLS prototype named v1.5. Furthermore the paper introduces detailed...

Energy and momentum management of the Space Station using magnetically suspended composite rotors

Science.gov (United States)

Eisenhaure, D. B.; Oglevie, R. E.; Keckler, C. R.

1985-01-01

The research addresses the feasibility of using magnetically suspended composite rotors to jointly perform the energy and momentum management functions of an advanced manned Space Station. Recent advancements in composite materials, magnetic suspensions, and power conversion electronics have given flywheel concepts the potential to simultaneously perform these functions for large, long duration spacecraft, while offering significant weight, volume, and cost savings over conventional approaches. The Space Station flywheel concept arising out of this study consists of a composite-material rotor, a large-angle magnetic suspension (LAMS) system, an ironless armature motor/generator, and high-efficiency power conversion electronics. The LAMS design permits the application of appropriate spacecraft control torques without the use of conventional mechanical gimbals. In addition, flywheel systems have the growth potential and modularity needed to play a key role in many future system developments.

Linear magnetic motor/generator. [to generate electric energy using magnetic flux for spacecraft power supply

Science.gov (United States)

Studer, P. A. (Inventor)

1982-01-01

A linear magnetic motor/generator is disclosed which uses magnetic flux to provide mechanical motion or electrical energy. The linear magnetic motor/generator includes an axially movable actuator mechanism. A permament magnet mechanism defines a first magnetic flux path which passes through a first end portion of the actuator mechanism. Another permament magnet mechanism defines a second magnetic flux path which passes through a second end portion of the actuator mechanism. A drive coil defines a third magnetic flux path passing through a third central portion of the actuator mechanism. A drive coil selectively adds magnetic flux to and subtracts magnetic flux from magnetic flux flowing in the first and second magnetic flux path.

Design and Construction of 10 kWh Class Flywheel Energy Storage System

International Nuclear Information System (INIS)

Jung, S. Y.; Han, S. C.; Han, Y. H.; Park, B. J.; Bae, Y. C.; Lee, W. R.

2011-01-01

A superconductor flywheel energy storage system (SFES) is an electro-mechanical battery which transforms electrical energy into mechanical energy for storage, and vice versa. A 10 kWh class flywheel energy storage system (FESS) has been developed to evaluate the feasibility of a 35 kWh class SFES with a flywheel Ip/If ratio larger than 1. The 10 kWh class FESS is composed of a main frame, a composite flywheel, active magnetic dampers (AMDs), a permanent magnet bearing, and a motor/generator. The flywheel of the FESS rotates at a very high speed to store energy, while being levitated by a permanent magnetic bearing and a pair of thrust AMDs. The 10 kWh class flywheel is mainly composed of a composite rotor assembly, where most of the energy is stored, two radial and two thrust AMD rotors, which dissipate vibration at critical speeds, a permanent magnet rotor, which supports most of the flywheel weight, a motor rotor, which spins the flywheel, and a central hollow shaft, where the parts are assembled and aligned to. The stators of each of the main components are assembled on to housings, which are assembled and aligned to the main frame. Many factors have been considered while designing each part of the flywheel, stator and frame. In this study, a 10 kWh class flywheel energy storage system has been designed and constructed for test operation.

Synthesis of magnetic systems producing field with maximal scalar characteristics

International Nuclear Information System (INIS)

Klevets, Nickolay I.

2005-01-01

A method of synthesis of the magnetic systems (MSs) consisting of uniformly magnetized blocks is proposed. This method allows to synthesize MSs providing maximum value of any magnetic field scalar characteristic. In particular, it is possible to synthesize the MSs providing the maximum of a field projection on a given vector, a gradient of a field modulus and a gradient of a field energy on a given directing vector, a field magnitude, a magnetic flux through a given surface, a scalar product of a field or a force by a directing function given in some area of space, etc. The synthesized MSs provide maximal efficiency of permanent magnets utilization. The usage of the proposed method of MSs synthesis allows to change a procedure of projecting in principal, namely, to execute it according to the following scheme: (a) to choose the sizes, a form and a number of blocks of a system proceeding from technological (economical) reasons; (b) using the proposed synthesis method, to find an orientation of site magnetization providing maximum possible effect of magnet utilization in a system obtained in (a). Such approach considerably reduces a time of MSs projecting and guarantees maximal possible efficiency of magnets utilization. Besides it provides absolute assurance in 'ideality' of a MS design and allows to obtain an exact estimate of the limit parameters of a field in a working area of a projected MS. The method is applicable to a system containing the components from soft magnetic material with linear magnetic properties

Review of Micro Magnetic Generator

OpenAIRE

Lin DU; Gengchen SHI; Jingjing ZHAO

2014-01-01

This paper discusses the research progress of micro magnetic generator systems. Micro magnetic generator systems convert energy from the environment to electric energy with advantages as high reliability, high power density, long life time and can be applied to extreme environment. This paper summarizes methods for improving generator performance of micro magnetic generator, including rotational magnetic generator, vibrational magnetic generator and hybrid magnetic generator, analyzes and com...

Magnetized retarding field energy analyzer measuring the particle flux and ion energy distribution of both positive and negative ions

International Nuclear Information System (INIS)

Rafalskyi, Dmytro; Aanesland, Ane; Dudin, Stanislav

2015-01-01

This paper presents the development of a magnetized retarding field energy analyzer (MRFEA) used for positive and negative ion analysis. The two-stage analyzer combines a magnetic electron barrier and an electrostatic ion energy barrier allowing both positive and negative ions to be analyzed without the influence of electrons (co-extracted or created downstream). An optimal design of the MRFEA for ion-ion beams has been achieved by a comparative study of three different MRFEA configurations, and from this, scaling laws of an optimal magnetic field strength and topology have been deduced. The optimal design consists of a uniform magnetic field barrier created in a rectangular channel and an electrostatic barrier consisting of a single grid and a collector placed behind the magnetic field. The magnetic barrier alone provides an electron suppression ratio inside the analyzer of up to 6000, while keeping the ion energy resolution below 5 eV. The effective ion transparency combining the magnetic and electrostatic sections of the MRFEA is measured as a function of the ion energy. It is found that the ion transparency of the magnetic barrier increases almost linearly with increasing ion energy in the low-energy range (below 200 eV) and saturates at high ion energies. The ion transparency of the electrostatic section is almost constant and close to the optical transparency of the entrance grid. We show here that the MRFEA can provide both accurate ion flux and ion energy distribution measurements in various experimental setups with ion beams or plasmas run at low pressure and with ion energies above 10 eV

Magnetic separation in microfluidic systems

DEFF Research Database (Denmark)

Smistrup, Kristian

2007-01-01

to facilitate real-time monitoring of the experiments. The set-up and experimental protocol are described in detail. Results are presented for ’active’ magnetic bead separators, where on-chip microfabricated electromagnets supply the magnetic field and field gradients necessary for magnetic bead separation....... It is shown conceptually how such a system can be applied for parallel biochemical processing in a microfluidic system. ’Passive’ magnetic separators are presented, where on-chip soft magnetic elements are magnetized by an external magnetic field and create strong magnetic fields and gradients inside...

Superconducting magnetic energy storage, possibilities and limitations

International Nuclear Information System (INIS)

Bace, M.; Knapp, V.

1981-01-01

Energy storage is of great importance for the exploitation of new energy sources as well as for the better utilisation of conventional ones. Several proposals in recent years have suggested that superconducting magnets could be used as energy storage in large electricity networks. It is a purpose of this note to point out that the requirements which have to be met by energy storage in a large electricity network place serious limitation on the possible use of superconducting energy storage. (author)

The international magnetic fusion energy program

International Nuclear Information System (INIS)

Fowler, T.K.

1988-01-01

In May of 1988, the long tradition of international cooperation in magnetic fusion energy research culminated in the initiation of design work on the International Thermonuclear Experimental Reactor (ITER). If eventually constructed in the 1990s, ITER would be the world's first magnetic fusion reactor. This paper discusses the background events that led to ITER and the present status of the ITER activity. This paper presents a brief summary of the technical, political, and organizational activities that have led to the creation of the ITER design activity. The ITER activity is now the main focus of international cooperation in magnetic fusion research and one of the largest international cooperative efforts in all of science. 2 refs., 12 figs

Magnetic phase diagram of the Ca1-xMnxO systems

International Nuclear Information System (INIS)

Masrour, R.; Hamedoun, M.

2008-01-01

The magnetic properties of the Ca 1-x Mn x O systems in the range 0≤x≤1 have been studied by mean field theory and high-temperature series expansions (HTSEs). By using the first theory, we have evaluated the nearest neighbour and the next-neighbour super-exchange interaction J 1 (x) and J 2 (x) respectively, in the range 0.45≤x≤1. The corresponding classical exchange energy for magnetic structure is obtained for the Ca 1-x Mn x O systems. The HTSEs combined with the Pade approximants (PA) method is applied to the Ca 1-x Mn x O systems; we have obtained the magnetic phase diagrams (T N or T SG versus dilution x) in the range 0≤x≤1. The obtained theoretical results are in agreement with experimental ones obtained by magnetic measurements. The critical exponents associated with the magnetic susceptibility (γ) and the correlation lengths (ν) are deduced in the range 0≤x≤1

Magnet power supply system for the ALS storage ring and booster

International Nuclear Information System (INIS)

Jackson, L.T.; Luchini, K.; Lutz, I.

1993-05-01

The Magnet Power Supply System is described by specification, design, hardware, and operating experience. A unique system for the one Hz, 1.5 GeV Booster, where the wideband QF and QD power supplies track the dipole current to within 0.1% at injection will be detailed. AC distribution system considerations related to inverting the stored energy of the booster magnet back into power grid will be discussed. The rational for linear correctors and individual quad supplies (225 total units) will be placed within the context of the storage-ring requirements

Duality of the magnetic flux tube and electric current descriptions magnetospheric plasma and energy flow

International Nuclear Information System (INIS)

Atkinson, G.

1981-01-01

The duality between electric current and magnetic flux tubes is outlined for the magnetosphere. Magnetic flux tubes are regarded as fluid elements subjected to various stresses. Current closure then becomes the dual of stress balance, and Poynting vector energy flow a dual of J x E dissipation. The stresses acting on a flux tube are magnetic stresses, which correspond to currents at a distance, and plasma stresses, which correspond to local currents. The duality between current and stress is traced for ionospheric ion drag forces, solar wind stresses at the magnetopause, inertial effects, and the effects of energetic plasma on flux tubes. The stress balance and dual current systems are outlined for idealized magnetospheres of increasing complexity. For a simple magnetosphere with no convective flow, the balance stresses are solar wind pressure and neutral sheet plasma pressure. The corresponding current systems are the Chapman-Ferraro magnetopause currents and the magetotail current system. The introduction of convective flow introduces further stresses: ionospheric ion drag. Alfven layer shielding, and an imbalance in day-night magnetic stresses due to transport of flux tubes to the nightside by the solar wind. These stresses balance, and hence the corresponding additional currents (the ionospheric Pedersen current and the electrojets, the partial ring current, and two other current systems from the magnetopause and tail) must form a closed current system and do so by the region I and II field-aligned currents of Iijima and Potemra. The energy flow in the above models is described in terms of both Poynting vectors and the above current systems. Temporal variations examined are (1) an increase in dayside merging and/or nightside reconnection, (2) an increase in the energy density of plasma in the plasma sheet, (3) an increase in ionospheric conductivity, and (4) an increase in solar wind pressure

Theory of a four-electron 2-D system in a strong magnetic field

International Nuclear Information System (INIS)

Yuandong Dai; Bingjian Ni; Fusui Liu.

1985-10-01

An orthogonal and complete set for relative motion of four-electron 2-D system in strong magnetic field is given, the energy of ground state of relative motion is calculated. This paper also calculates the energy of ground state whose maximum of single electron angular momentum is limited by the degeneracy under a given magnetic field, obtains the energy minimums corresponding to a fractional quantized Hall effect of 2/5, 2/7, and from it the physical meaning of 'magic number' is interpreted. (author)

Exploration of Fermi-Pasta-Ulam Behavior in a Magnetic System

Science.gov (United States)

Lewis, Jeramy; Camley, Robert E.; Anderson, Nicholas R.

2018-04-01

We study nonlinear spin motion in one-dimensional magnetic chains. We find significant differences from the classic Fermi-Pasta-Ulam (FPU) problem examining nonlinear elastic motion in a chain. We find that FPU behavior, the transfer of energy among low order eigenmodes, does not occur in magnetic systems with only exchange and external fields, but does exist if a uniaxial anisotropy is also present. The FPU behavior may be altered or turned off through the magnitude and orientation of an external magnetic field. A realistic micromagnetic model shows such behavior could be measurable.

A design approach for systems based on magnetic pulse compression

International Nuclear Information System (INIS)

Praveen Kumar, D. Durga; Mitra, S.; Senthil, K.; Sharma, D. K.; Rajan, Rehim N.; Sharma, Archana; Nagesh, K. V.; Chakravarthy, D. P.

2008-01-01

A design approach giving the optimum number of stages in a magnetic pulse compression circuit and gain per stage is given. The limitation on the maximum gain per stage is discussed. The total system volume minimization is done by considering the energy storage capacitor volume and magnetic core volume at each stage. At the end of this paper, the design of a magnetic pulse compression based linear induction accelerator of 200 kV, 5 kA, and 100 ns with a repetition rate of 100 Hz is discussed with its experimental results

Study of multi-level atomic systems with the application of magnetic field

Science.gov (United States)

Hu, Jianping; Roy, Subhankar; Ummal Momeen, M.

2018-04-01

The complexity of multiple energy levels associated with each atomic system determines the various processes related to light- matter interactions. It is necessary to understand the influence of different levels in a given atomic system. In this work we focus on multi- level atomic schemes with the application of magnetic field. We analyze the different EIT windows which appears in the presence of moderately high magnetic field (∼ 10 G) strength.

High-energy electron irradiation of NdFeB permanent magnets: Dependence of radiation damage on the electron energy

Energy Technology Data Exchange (ETDEWEB)

Bizen, Teruhiko [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan)]. E-mail: bizen@spring8.or.jp; Asano, Yoshihiro [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); RIKEN SPring-8 Center, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Marechal, Xavier-Marie [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Seike, Takamitsu [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Aoki, Tsuyoshi [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Fukami, Kenji [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Hosoda, Naoyasu [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Yonehara, Hiroto [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Takagi, Tetsuya [JASRI SPring-8, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Hara, Toru [RIKEN SPring-8 Center, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Tanaka, Takashi [RIKEN SPring-8 Center, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Kitamura, Hideo [RIKEN SPring-8 Center, 1-1-1 Kouto Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan)

2007-05-11

High-energy electron-beam bombardment of Nd{sub 2}Fe{sub 14}B-type permanent magnets induces radiation damage characterized by a drop in the magnetic field. Experiments carried out at the SPring-8 booster synchrotron, with 4, 6, and 8 GeV electrons, show that the drop in magnetic field is energy dependent. Electromagnetic shower simulations suggest that most of the radiation damage happens in a small region around the irradiation axis, and that the contribution of neutrons with large scattering angles or with low energies to the magnetic field change is small.

High-energy electron irradiation of NdFeB permanent magnets: Dependence of radiation damage on the electron energy

International Nuclear Information System (INIS)

Bizen, Teruhiko; Asano, Yoshihiro; Marechal, Xavier-Marie; Seike, Takamitsu; Aoki, Tsuyoshi; Fukami, Kenji; Hosoda, Naoyasu; Yonehara, Hiroto; Takagi, Tetsuya; Hara, Toru; Tanaka, Takashi; Kitamura, Hideo

2007-01-01

High-energy electron-beam bombardment of Nd 2 Fe 14 B-type permanent magnets induces radiation damage characterized by a drop in the magnetic field. Experiments carried out at the SPring-8 booster synchrotron, with 4, 6, and 8 GeV electrons, show that the drop in magnetic field is energy dependent. Electromagnetic shower simulations suggest that most of the radiation damage happens in a small region around the irradiation axis, and that the contribution of neutrons with large scattering angles or with low energies to the magnetic field change is small

Effect of the magnetic dipole interaction on a spin-1 system

Science.gov (United States)

Hu, Fangqi; Jia, Wei; Zhao, Qing

2018-05-01

We consider a hybrid system composed of a spin-1 triplet coupled to a nuclear spin. We study the effect of the axisymmetric and the quadrupole term of the magnetic dipole interaction between the two electrons forming the triplet on the energy spectrum in a static magnetic field. The energy spectrum obtained by directly diagonalizing the Hamiltonian of the system shows that these two terms not only remove the special crossings that appear in the absence of the magnetic dipole interaction, but also produce new (avoided) crossings by lifting the relevant levels. Specially, the gaps between the avoided crossing levels increase with the strength of the quadrupole term. In order to accurately illustrate these effects, we present the results for the discriminant and von Neumann entropy of one electron interacting with the rest of the whole system. Finally, by numerically solving the time-dependent Schrödinger equations of the system, we discover that the polarization oscillation of electron and nuclear spin is in-phase and the total average longitudinal spin is not conserved at location of avoided crossing, but the two results are opposite beyond that.

Superconducting magnet system for the AGS high energy unseparated beam

International Nuclear Information System (INIS)

Morgan, G.; Aggus, J.; Bamberger, J.

1975-01-01

A beam line to the Multi-Particle Spectrometer capable of handling 30 GeV/c secondary beams will consist of four large identical superconducting dipoles and a number of room temperature quadrupoles. The total bending angle is 20 0 , 5 0 per magnet, and the room temperature aperture required in the dipoles is 20 cm. The four dipoles will be of the cos theta type and will have an overall length of 2.5 m and nominal maximum field of 4.0 T at 2800 A. The conductor will be a thin, wide metal-impregnated braid. The circular aperture is surrounded by coils which are a six-block approximation to a single-layer cos theta current sheet, and a coaxial cylinder of laminated iron at helium temperature. Each magnet will weigh about 10 tons. The design of the dewar including its heat load is discussed. The system is planned to be operational in Fall 1975. (U.S.)

Energy and helicity of magnetic torus knots and braids

Science.gov (United States)

Oberti, Chiara; Ricca, Renzo L.

2018-02-01

By considering steady magnetic fields in the shape of torus knots and unknots in ideal magnetohydrodynamics, we compute some fundamental geometric and physical properties to provide estimates for magnetic energy and helicity. By making use of an appropriate parametrization, we show that knots with dominant toroidal coils that are a good model for solar coronal loops have negligible total torsion contribution to magnetic helicity while writhing number provides a good proxy. Hence, by the algebraic definition of writhe based on crossing numbers, we show that the estimated values of writhe based on image analysis provide reliable information for the exact values of helicity. We also show that magnetic energy is linearly related to helicity, and the effect of the confinement of magnetic field can be expressed in terms of geometric information. These results can find useful application in solar and plasma physics, where braided structures are often present.

A Motor/Generator for Flywheel Energy Storage System Levitated by Bulk Superconductor

Energy Technology Data Exchange (ETDEWEB)

Koh, C.S.; Yeon, J.U.; Jeoung, H.M.; Choi, J.H. [Chungbuk National University (Korea); Lee, H.J; Hong, G.W. [Korea Atomic Energy Research Institute (Korea)

2000-06-01

The energy storage systems are being widely researched for the high quality of the electric power. The FES(flywheel energy storage system)is especially, on the center of the research because it does not make any pollution and its life is long. The FES converts the electrical energy into the mechanical kinetic energy of the flywheel and reconverts the mechanical energy into the electrical energy, In order to store as much energy as possible, the flywheel is supposed to be rotated with very high speed. The motor/generator of the FES should be high efficient at high speed, and generate constant torque with respect to the rotation. In this paper, a motor/generator employing a Halbach array of permanent magnets is designed and constructed to meet the requirements, and its characteristics are examined. The magnetic field is analysed by using the magnetic surface charge method. The armature winding is designed for the harmonic components to be minimized by using the FFT. The sinusoidal currents for the motor driving are generated by the hysteresis current controller. A sample superconducting flywheel energy storage system is constructed with a duralumin flywheel which has a maximum rotating speed of 40,000[rpm] and a stored energy of 240[Wh] and its validity is examined through the experiment. (author). 15 refs., 17 figs., 2 tabs.

High energy permanent magnets - Solutions to high performance devices

International Nuclear Information System (INIS)

Ma, B.M.; Willman, C.J.

1986-01-01

Neodymium iron boron magnets are a special class of magnets providing the highest level of performance with the least amount of material. Crucible Research Center produced the highest energy product magnet of 45 MGOe - a world record. Commercialization of this development has already taken place. Crucible Magnetics Division, located in Elizabethtown, Kentucky, is currently manufacturing and marketing six different grades of NdFeB magnets. Permanent magnets find application in motors, speakers, electron beam focusing devices for military and Star Wars. The new NdFeB magnets are of considerable interest for a wide range of applications

Control strategy of wind turbine based on permanent magnet synchronous generator and energy storage for stand-alone systems

DEFF Research Database (Denmark)

Deng, Fujin; Liu, Dong; Chen, Zhe

2017-01-01

This paper investigates a variable speed wind turbine based on permanent magnet synchronous generator and a full-scale power converter in a stand-alone system. An energy storage system(ESS) including battery and fuel cell-electrolyzer combination is connected to the DC link of the full-scale power...... converter through the power electronics interface. Wind is the primary power source of the system, the battery and FC-electrolyzer combination is used as a backup and a long-term storage system to provide or absorb power in the stand-alone system, respectively. In this paper, a control strategy is proposed...... for the operation of this variable speed wind turbine in a stand-alone system, where the generator-side converter and the ESS operate together to meet the demand of the loads. This control strategy is competent for supporting the variation of the loads or wind speed and limiting the DC-link voltage of the full...

Tandem mirror magnet system for the mirror fusion test facility

International Nuclear Information System (INIS)

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

1980-01-01

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

Reduced energy conservation law for magnetized plasma

International Nuclear Information System (INIS)

Sosenko, P.P.; Decyk, V.K.

1994-01-01

A global energy conservation law for a magnetized plasma is studied within the context of a quasiparticle description. A reduced energy conservation law is derived for low-frequency, as compared to the gyromagnetic frequency, plasma motions with regard to both non-uniform mean flows and fluctuations in the plasma. The mean value of plasma energy is calculated and sufficient stability conditions for non-equilibrium plasmas are derived. (orig.)

The international magnetic fusion energy program

Energy Technology Data Exchange (ETDEWEB)

Fowler, T.K.

1988-10-06

In May of 1988, the long tradition of international cooperation in magnetic fusion energy research culminated in the initiation of design work on the International Thermonuclear Experimental Reactor (ITER). If eventually constructed in the 1990s, ITER would be the world's first magnetic fusion reactor. This paper discusses the background events that led to ITER and the present status of the ITER activity. This paper presents a brief summary of the technical, political, and organizational activities that have led to the creation of the ITER design activity. The ITER activity is now the main focus of international cooperation in magnetic fusion research and one of the largest international cooperative efforts in all of science. 2 refs., 12 figs.

Free Magnetic Energy and Coronal Heating

Science.gov (United States)

Winebarger, Amy; Moore, Ron; Falconer, David

2012-01-01

Previous work has shown that the coronal X-ray luminosity of an active region increases roughly in direct proportion to the total photospheric flux of the active region's magnetic field (Fisher et al. 1998). It is also observed, however, that the coronal luminosity of active regions of nearly the same flux content can differ by an order of magnitude. In this presentation, we analyze 10 active regions with roughly the same total magnetic flux. We first determine several coronal properties, such as X-ray luminosity (calculated using Hinode XRT), peak temperature (calculated using Hinode EIS), and total Fe XVIII emission (calculated using SDO AIA). We present the dependence of these properties on a proxy of the free magnetic energy of the active region

Method for providing slip energy control in permanent magnet electrical machines

Science.gov (United States)

Hsu, John S.

2006-11-14

An electric machine (40) has a stator (43), a permanent magnet rotor (38) with permanent magnets (39) and a magnetic coupling uncluttered rotor (46) for inducing a slip energy current in secondary coils (47). A dc flux can be produced in the uncluttered rotor when the secondary coils are fed with dc currents. The magnetic coupling uncluttered rotor (46) has magnetic brushes (A, B, C, D) which couple flux in through the rotor (46) to the secondary coils (47c, 47d) without inducing a current in the rotor (46) and without coupling a stator rotational energy component to the secondary coils (47c, 47d). The machine can be operated as a motor or a generator in multi-phase or single-phase embodiments and is applicable to the hybrid electric vehicle. A method of providing a slip energy controller is also disclosed.

On the cosmological propagation of high energy particles in magnetic fields

International Nuclear Information System (INIS)

Alves Batista, Rafael

2015-04-01

In the present work the connection between high energy particles and cosmic magnetic fields is explored. Particularly, the focus lies on the propagation of ultra-high energy cosmic rays (UHECRs) and very-high energy gamma rays (VHEGRs) over cosmological distances, under the influence of cosmic magnetic fields. The first part of this work concerns the propagation of UHECRs in the magnetized cosmic web, which was studied both analytically and numerically. A parametrization for the suppression of the UHECR flux at energies ∝ 10 18 eV due to diffusion in extragalactic magnetic fields was found, making it possible to set an upper limit on the energy at which this magnetic horizon effect sets in, which is energy loss and interaction processes as well as effects of galactic and extragalactic magnetic fields. The newest version, CRPropa 3, is discussed in details, including the novel feature of cosmological effects in three-dimensional simulations, which enables time dependent studies considering simultaneously magnetic field effects and the cosmological evolution of the universe. An interesting possibility is to use UHECRs to constrain properties of cosmic magnetic fields, and vice-versa. Numerical simulations of the propagation of UHECRs in the magnetized cosmic web, obtained through magnetohydrodynamical simulations of structure formation, were performed. It was studied the effects of different magnetic field seeds on the distribution of cosmic magnetic fields today, and their impact on the propagation of cosmic rays. Furthermore, the influence of uncertainties of the strength of

Energy Extracting and Quench Protection System in the LHC

CERN Document Server

Abu Siam, Mansour

2016-01-01

quadrupole magnets. The electromagnets are built of special cables that operate in superconducting state by cooling them to 1.9K (-271.3℃); the superconducting magnets of the LHC are powered in about 1700 electrical circuits. A phenomenon called quench can spontaneously occur in superconducting magnets, which means that the superconductivity is lost in part of their windings. The energy stored within the magnet, up to 1.3 GJ, can cause severe damage. In order to protect the superconducting elements after a resistive transition, the energy is dissipated into a dump resistor installed in series with the magnet chain that is switched into the circuit by opening circuit breakers. The system described above is utilized for magnets installed in the LHC that operate under currents ranging from 600A up to 13kA. For the next LHC upgrade (High Luminosity) there is a need for circuit breakers capable of interrupting high DC currents in a solely inductive circuit within one millisecond and under development of very hig...

The Maximum Free Magnetic Energy Allowed in a Solar Active Region

Science.gov (United States)

Moore, Ronald L.; Falconer, David A.

2009-01-01

Two whole-active-region magnetic quantities that can be measured from a line-of-sight magnetogram are (sup L) WL(sub SG), a gauge of the total free energy in an active region's magnetic field, and sup L(sub theta), a measure of the active region's total magnetic flux. From these two quantities measured from 1865 SOHO/MDI magnetograms that tracked 44 sunspot active regions across the 0.5 R(sub Sun) central disk, together with each active region's observed production of CMEs, X flares, and M flares, Falconer et al (2009, ApJ, submitted) found that (1) active regions have a maximum attainable free magnetic energy that increases with the magnetic size (sup L) (sub theta) of the active region, (2) in (Log (sup L)WL(sub SG), Log(sup L) theta) space, CME/flare-productive active regions are concentrated in a straight-line main sequence along which the free magnetic energy is near its upper limit, and (3) X and M flares are restricted to large active regions. Here, from (a) these results, (b) the observation that even the greatest X flares produce at most only subtle changes in active region magnetograms, and (c) measurements from MSFC vector magnetograms and from MDI line-of-sight magnetograms showing that practically all sunspot active regions have nearly the same area-averaged magnetic field strength: =- theta/A approximately equal to 300 G, where theta is the active region's total photospheric flux of field stronger than 100 G and A is the area of that flux, we infer that (1) the maximum allowed ratio of an active region's free magnetic energy to its potential-field energy is 1, and (2) any one CME/flare eruption releases no more than a small fraction (less than 10%) of the active region's free magnetic energy. This work was funded by NASA's Heliophysics Division and NSF's Division of Atmospheric Sciences.

Spontaneous transfer of magnetically stored energy to Kinetic energy by electric double layers

International Nuclear Information System (INIS)

Lindberg, L.; Torven, S.

1983-05-01

Current disruptions are investigated in a magnetized plasma column with an inductive external electric circuit. It is found that they persist in spite of the fact that each disruption gives rise to a large inductive over-voltage. This drops off at an electric double layer formed in the plasma where most of the magnetic energy, initially stored in the circuit inductance, is released as particle energy. Simultanously as the current disrupts, the potential level at a local potential minimum in the plasma decreases. This is expected to cause the disruption by reflection of electrons. (authors)

Experimental Analysis of a Coupled Energy Harvesting System with Monostable and Bistable Configuration

International Nuclear Information System (INIS)

Hoffmann, D; Folkmer, B; Manoli, Y

2014-01-01

In this paper we present experimental results from an energy harvesting system with two coupled energy harvesters. The energy conversion mechanism of the two coupled energy harvesters is based on the electromagnetic principle. The coupling is generated by two magnets in a repulsive arrangement. In this manner a bistable configuration can be obtained if the gap between the magnets is sufficiently small. We demonstrate that the total power output can be increased in comparison to a linear reference system, if specific conditions are fulfilled. In this respect, the highest power output occurs in the nonlinear region of a monostable system configuration, mostly near the transition to a bistable configuration. On the other hand, the results also indicate, that a bistable operating mode does not necessarily enhance the power output of the coupled system

Specific features of designs of superconducting magnets for high-energy synchrotrons

International Nuclear Information System (INIS)

Monoszon, N.A.

1979-01-01

Distinctive features of designs of synchrotron superconducting magnetic systems (SMS) are considered. Some results of testing the prototypes of the ISABELLE storage ring magnets, the DABLER energy doubler and the accelerating-storage complex project are presented. Designs of di.ooles and quadrupoles are described. It is shown that the design of the DABLER SMS considerably differs from the ISABELLE SMS. The DABLER uses nonsaturated magnetic screens which provide lesser distortions of the magnetic field distribution. For the ISABELLE project a dipole with a two-layer winding has been developed which produced a field of 6.2 T. Magnetization curves as well as training and field distribution curves for a number of DABLER dipoles are presented. To prevent local overheating provision is made for using a heater enclosed in a winding. A 1 m dipole model with a sector winding of the DABLER type has been manufactured and tested in the IHEP. During tests a short-sample current and a total value of calculated field equal to 4.45 T in the chamber centre amd 5.3 T in the winding have been achieved

Scaling the energy conversion rate from magnetic field reconnection to different bodies

International Nuclear Information System (INIS)

Mozer, F. S.; Hull, A.

2010-01-01

Magnetic field reconnection is often invoked to explain electromagnetic energy conversion in planetary magnetospheres, stellar coronae, and other astrophysical objects. Because of the huge dynamic range of magnetic fields in these bodies, it is important to understand energy conversion as a function of magnetic field strength and related parameters. It is conjectured theoretically and shown experimentally that the energy conversion rate per unit area in reconnection scales as the cube of an appropriately weighted magnetic field strength divided by the square root of an appropriately weighted density. With this functional dependence, the energy release in flares on the Sun, the large and rapid variation of the magnetic flux in the tail of Mercury, and the apparent absence of reconnection on Jupiter and Saturn, may be understood. Electric fields at the perihelion of the Solar Probe Plus mission may be tens of V/m.

Progress of magnetic-suspension systems and magnetic bearings in the USSR

International Nuclear Information System (INIS)

Kuzin, A.V.

1992-01-01

This paper traces the development and progress of magnetic suspension systems and magnetic bearings in the USSR. The paper describes magnetic bearings for turbomachines, magnetic suspension systems for vibration isolation, some special measuring devices, wind tunnels, and other applications. The design, principles of operation, and dynamic characteristics of the system are presented

Low-energy-state dynamics of entanglement for spin systems

International Nuclear Information System (INIS)

Jafari, R.

2010-01-01

We develop the ideas of the quantum renormalization group and quantum information by exploring the low-energy-state dynamics of entanglement resources of a system close to its quantum critical point. We demonstrate that low-energy-state dynamical quantities of one-dimensional magnetic systems can show a quantum phase transition point and show scaling behavior in the vicinity of the transition point. To present our idea, we study the evolution of two spin entanglements in the one-dimensional Ising model in the transverse field. The system is initialized as the so-called thermal ground state of the pure Ising model. We investigate the evolution of the generation of entanglement with increasing magnetic field. We obtain that the derivative of the time at which the entanglement reaches its maximum with respect to the transverse field diverges at the critical point and its scaling behaviors versus the size of the system are the same as the static ground-state entanglement of the system.

Influence of disorder and magnetic field on conductance of “sandwich” type two dimensional system

Directory of Open Access Journals (Sweden)

Long LIU

2017-04-01

Full Text Available In order to discuss the transport phenomena and the physical properties of the doping of the disorder system under magnetic field, the electron transport in a two-dimensional system is studied by using Green function and scattering matrix theory. Base on the two-dimensional lattice model, the phenomenon of quantized conductance of the "sandwich" type electronic system is analyzed. The contact between the lead and the scatterer reduce the system's conductance, and whittle down the quantum conductance stair-stepping phenomenon; when an external magnetic field acts on to the system, the conductance presents a periodicity oscillation with the magnetic field. The intensity of this oscillation is related to the energy of the electron;with the increase of the impurity concentration, the conductance decreases.In some special doping concentration, the conductance of the system can reach the ideal step value corresponding to some special electron energy. The result could provide reference for further study of the conductance of the "sandwich" type two dimensional system.

A Vertical Flux-Switching Permanent Magnet Based Oscillating Wave Power Generator with Energy Storage

Directory of Open Access Journals (Sweden)

Yu Zou

2017-06-01

Full Text Available In this paper, an effective low-speed oscillating wave power generator and its energy storage system have been proposed. A vertical flux-switching permanent magnet (PM machine is designed as the generator while supercapacitors and batteries are used to store the energy. First, the overall power generation system is established and principles of the machine are introduced. Second, three modes are proposed for the energy storage system and sliding mode control (SMC is employed to regulate the voltage of the direct current (DC bus, observe the mechanical input, and feedback the status of the storage system. Finally, experiments with load and sinusoidal mechanical inputs are carried out to validate the effectiveness and stability of power generation for wave energy. The results show that the proposed power generation system can be employed in low-speed environment around 1 m/s to absorb random wave power, achieving over 60% power efficiency. The power generation approach can be used to capture wave energy in the future.

The need for control of magnetic parameters for energy efficient performance of magnetic tunnel junctions

Science.gov (United States)

Farhat, I. A. H.; Gale, E.; Alpha, C.; Isakovic, A. F.

2017-07-01

Optimizing energy performance of Magnetic Tunnel Junctions (MTJs) is the key for embedding Spin Transfer Torque-Random Access Memory (STT-RAM) in low power circuits. Due to the complex interdependencies of the parameters and variables of the device operating energy, it is important to analyse parameters with most effective control of MTJ power. The impact of threshold current density, Jco , on the energy and the impact of HK on Jco are studied analytically, following the expressions that stem from Landau-Lifshitz-Gilbert-Slonczewski (LLGS-STT) model. In addition, the impact of other magnetic material parameters, such as Ms , and geometric parameters such as tfree and λ is discussed. Device modelling study was conducted to analyse the impact at the circuit level. Nano-magnetism simulation based on NMAGTM package was conducted to analyse the impact of controlling HK on the switching dynamics of the film.

Microwave generation for magnetic fusion energy applications, Task A

International Nuclear Information System (INIS)

Antonsen, T.M. Jr.; Destler, W.W.; Granatstein, V.L.; Levush, B.; Mayergoyz, I.D.; Singh, A.

1990-05-01

This report details progress over the past year in the research program ''Free Electron Lasers with Short Period Wigglers.'' The work is performed jointly by the laboratory for Plasma Research and the Electrical Engineering Department of the University of Maryland and is funded by the US Department of Energy Office of Fusion Energy. The goal of the work is the development of an electron cyclotron resonance heating (ECRH) scheme for magnetic fusion plasmas such as the Compact Ignition Tokamak (CIT). Our approach is the development of a free electron laser using a sheet electron beam and a short period wiggler magnet. The specific requirements for the heating method include 10 to 30 MW of average power with pulse durations of several seconds to CW at a frequency near 300 GHz (∼600 GHz) in the case of second harmonic (ECRH). Compatible with the experimental nature of the program, radiation frequency flexibility of 30% total bandwidth and 5% rapid dynamic (approx-lt 10 ms) bandwidth is desirable. As the source will eventually be applied to a reactor, priority is placed upon high system efficiency and reliability. Use of established technologies is encouraged where possible

Anomalous magnetic viscosity in α-Fe(Co)/(Nd,Pr)2Fe14B exchange-spring magnet

International Nuclear Information System (INIS)

Hai, Nguyen Hoang; Chau, Nguyen; Ngo, Duc-The; Gam, Duong Thi Hong

2011-01-01

This article presents an anomalous magnetic viscosity in α-Fe(Co)/(Nd,Pr) 2 Fe 14 B exchange-spring magnet. A similar effect has been observed in non-interacting or weakly interacting systems but not in a strong interacting magnetic systems. We reported a new procedure to measure magnetic relaxation under various magnetic fields. Changing the applied magnetic field by different field protocols during the reversal process, we found that a memory effect of the magnetization appeared if the field change is large enough. The mechanism of the phenomenon can be explained in the model of conventional magnetic reversal in strong ferromagnetic systems with an energy barrier distribution. The study of such magnetic relaxations can provide some information related to the energy barrier distribution function. - Highlights: → The memory effect was observed in a strong magnetically interacting system. → The memory effect on hard magnets can be explained by conventional reversal mechanism. → And it provides some information of the energy barrier for the reversal of magnetic moments.

Enhancing the utilization of photovoltaic power generation by superconductive magnetic energy storage

International Nuclear Information System (INIS)

Tam, K.S.; Kumar, P.; Foreman, M.

1989-01-01

This paper demonstrates that a superconductive magnetic energy storage (SMES) system can enhance large scale utilization of PV generation. With SMES support, power generated from PV arrays van be fully utilized under different weather conditions and PV penetrations can be increased to significant levels without causing adverse effects to the power system. Coupled with PV generation, a SMES system is even more effective in performing diurnal load leveling. A coordinated PV/SMES operation scheme is proposed and demonstrated under different weather conditions

Magnetic fusion energy research and development

International Nuclear Information System (INIS)

1984-02-01

This report on the Department of Energy's Magnetic Fusion Program was requested by the Secretary of Energy. The Panel finds that substantial progress has been made in the three years since the previous ERAB review, although budget constraints have precluded the engineering initiatives recommended in that review and authorized in the Magnetic Fusion Energy Engineering Act of 1980 (the Act). Recognizing that the goals of the Act cannot now be met, the Panel recommends that the engineering phase be further postponed in favor of a strong base program in physics and technology, including immediate commitment to a major new tokamak-based device for the investigation of an ignited long-pulse plasma designated in this report as the Burning Core Experiment or BCX. Resources to design such a device could be obtained from within the existing program by redirecting work toward to BCX. At this time it is not possible to assess accurately the potential economic viability of fusion power in the future. The Panel strongly recommends expansion of international collaboration, particularly the joint construction and operation of major new unique facilities, such as the proposed BCX

Photovoltaic-wind hybrid system for permanent magnet DC motor

Science.gov (United States)

Nasir, M. N. M.; Lada, M. Y.; Baharom, M. F.; Jaafar, H. I.; Ramani, A. N.; Sulaima, M. F.

2015-05-01

Hybrid system of Photovoltaic (PV) - Wind turbine (WT) generation has more advantages and reliable compared to PV or wind turbine system alone. The aim of this paper is to model and design hybrid system of PV-WT supplying 100W permanent-magnet dc motor. To achieve the objective, both of PV and WT are connected to converter in order to get the same source of DC supply. Then both sources were combined and straightly connected to 100W permanent magnet dc motor. All the works in this paper is only applied in circuit simulator by using Matlab Simulink. The output produced from each converter is expected to be suit to the motor specification. The output produced from each renewable energy system is as expected to be high as it can support the motor if one of them is breakdown

Magnetic Energy and Helicity in Two Emerging Active Regions in the Sun

Science.gov (United States)

Liu, Y.; Schuck, P. W.

2012-01-01

The magnetic energy and relative magnetic helicity in two emerging solar active regions, AR 11072 and AR 11158,are studied. They are computed by integrating over time the energy and relative helicity fluxes across the photosphere. The fluxes consist of two components: one from photospheric tangential flows that shear and braid field lines (shear term), the other from normal flows that advect magnetic flux into the corona (emergence term). For these active regions: (1) relative magnetic helicity in the active-region corona is mainly contributed by the shear term,(2) helicity fluxes from the emergence and the shear terms have the same sign, (3) magnetic energy in the corona (including both potential energy and free energy) is mainly contributed by the emergence term, and(4) energy fluxes from the emergence term and the shear term evolved consistently in phase during the entire flux emergence course.We also examine the apparent tangential velocity derived by tracking field-line footpoints using a simple tracking method. It is found that this velocity is more consistent with tangential plasma velocity than with the flux transport velocity, which agrees with the conclusion by Schuck.

A first-principles study of the possible magnetism of Rh in the Cu/Rh/Cu(001) system

CERN Document Server

Jang, Y R; Chang, C S; Cho, L H; Lee, J I

1999-01-01

Possible 4d magnetism of a Rh monolayer in a Cu/Rh/Cu(001) system is investigated using the full-potential linearized augmented-plane-wave (FLAPW) energy band method based on the local-spin-density approximation (LSDA). We have calculated the total energy of the Cu/Rh/Cu(001) system and have found that the Rh monolayer is ferromagnetic (FM) with a tiny magnetic moment. However, the total energy difference between the ferromagnetic and the paramagnetic states is found to be very small, and thus which state can be realized at room temperature is uncertain. The calculated charge densities and layer-projected density of states (LDOS) are presented and discussed in relation to the magnetic properties.

Design of Anti-windup Compensator for Superconducting Magnetic Energy Storage

DEFF Research Database (Denmark)

Fang, Jiakun; Chen, Zhe; Su, Chi

2013-01-01

-windup compensator (AWC) is applied to the controller of the superconducting magnetic energy storage (SMES) system to improve power system stability. First, power system with actuator saturation is described to formulate the problem mathematically. Then, uniform anti-windup scheme is studied and compensator...... is designed with method of linear matrix inequality (LMI). Instead of replacing the original controller with a new one, the anti-windup compensation make use of the difference between the controller’s and the actuator’s output to mitigate the adverse influence of saturation, which leaves the original...... controller unaffected. Hence, this method can be used to enhance power system stability under the same capacity with its unsaturated controller so that SMES is utilized more efficiently....

Effects from magnetic boundary conditions in superconducting-magnetic proximity systems

Directory of Open Access Journals (Sweden)

Thomas E. Baker

2016-05-01

Full Text Available A superconductor-magnetic proximity system displays singlet-triplet pair correlations in the magnetization as a function of inhomogeneities of the magnetic profile. We discuss how the magnetic boundary conditions affects differently the curvature and winding number of rotating magnetizations in the three commonly used structures to generate long range triplet components: an exchange spring, a helical structure and a misaligned magnetic multilayer. We conclude that the choice of the system is dictated by the goal one wishes to achieve in designing a spintronic device but note that only the exchange spring presently offers an experimentally realizable magnetic profile that is tunable.

Magnetic tornadoes as energy channels into the solar corona.

Science.gov (United States)

Wedemeyer-Böhm, Sven; Scullion, Eamon; Steiner, Oskar; van der Voort, Luc Rouppe; de la Cruz Rodriguez, Jaime; Fedun, Viktor; Erdélyi, Robert

2012-06-27

Heating the outer layers of the magnetically quiet solar atmosphere to more than one million kelvin and accelerating the solar wind requires an energy flux of approximately 100 to 300 watts per square metre, but how this energy is transferred and dissipated there is a puzzle and several alternative solutions have been proposed. Braiding and twisting of magnetic field structures, which is caused by the convective flows at the solar surface, was suggested as an efficient mechanism for atmospheric heating. Convectively driven vortex flows that harbour magnetic fields are observed to be abundant in the photosphere (the visible surface of the Sun). Recently, corresponding swirling motions have been discovered in the chromosphere, the atmospheric layer sandwiched between the photosphere and the corona. Here we report the imprints of these chromospheric swirls in the transition region and low corona, and identify them as observational signatures of rapidly rotating magnetic structures. These ubiquitous structures, which resemble super-tornadoes under solar conditions, reach from the convection zone into the upper solar atmosphere and provide an alternative mechanism for channelling energy from the lower into the upper solar atmosphere.

High-Energy Electron Confinement in a Magnetic Cusp Configuration

Directory of Open Access Journals (Sweden)

Jaeyoung Park

2015-06-01

Full Text Available We report experimental results validating the concept that plasma confinement is enhanced in a magnetic cusp configuration when β (plasma pressure/magnetic field pressure is of order unity. This enhancement is required for a fusion power reactor based on cusp confinement to be feasible. The magnetic cusp configuration possesses a critical advantage: the plasma is stable to large scale perturbations. However, early work indicated that plasma loss rates in a reactor based on a cusp configuration were too large for net power production. Grad and others theorized that at high β a sharp boundary would form between the plasma and the magnetic field, leading to substantially smaller loss rates. While not able to confirm the details of Grad’s work, the current experiment does validate, for the first time, the conjecture that confinement is substantially improved at high β. This represents critical progress toward an understanding of the plasma dynamics in a high-β cusp system. We hope that these results will stimulate a renewed interest in the cusp configuration as a fusion confinement candidate. In addition, the enhanced high-energy electron confinement resolves a key impediment to progress of the Polywell fusion concept, which combines a high-β cusp configuration with electrostatic fusion for a compact, power-producing nuclear fusion reactor.

Superconductivity application technologies. Superconducting quadrupole magnet and cooling system for KEK B factory

International Nuclear Information System (INIS)

Tsuchiya, Kiyosumi; Yamaguchi, Kiyoshi; Sakurabata, Hiroaki; Seido, Masahiro; Matsumoto, Kozo.

1997-01-01

At present in National Laboratory for High Energy Physics (KEK), the construction of B factory is in progress. By colliding 8 GeV electrons and 3.5 GeV positrons, this facility generates large amounts of B mesons and anti-B mesons, and performs the elementary particle experiment of high accuracy. It is the collision type accelerator of asymmetric two-ring type comprising 8 GeV and 3.5 GeV rings. In the field of high energy physics, superconductivity technology has been put to practical use. As the objects of superconductivity technology, there are dipole magnet for bending beam, quadrupole magnet for adjusting beam, large solenoid magnet used for detector and so on. Superconducting magnets which are indispensable for high energy, superconducting wire material suitable to accelerators, and the liquid helium cooling system for maintaining superconducting magnets at 4.4 K are reported. The technologies of metallic conductors and making their coils have advanced rapidly, and also cooling technology has advanced, accordingly, superconductivity technology has reached the stage of practical use perfectly. (K.I.)

Magnetic effects in heavy-ion collisions at intermediate energies

International Nuclear Information System (INIS)

Ou Li; Li Baoan

2011-01-01

The time evolution and space distribution of internal electromagnetic fields in heavy-ion reactions at beam energies between 200 and 2000 MeV/nucleon are studied within an isospin-dependent Boltzmann-Uhling-Uhlenbeck transport model (ibuu11). While the magnetic field can reach about 7x10 16 G, which is significantly higher than the estimated surface magnetic field (∼1x10 15 G) of magnetars, it has almost no effect on nucleon observables because the Lorentz force is normally much weaker than the nuclear force. Very interestingly, however, the magnetic field generated by the projectilelike (targetlike) spectator has a strong focusing and defocusing effect on positive and negative pions at forward (backward) rapidities. Consequently, the differential π - /π + ratio as a function of rapidity is significantly altered by the magnetic field, whereas the total multiplicities of both positive and negative pions remain about the same. At beam energies above about 1 GeV/nucleon, while the integrated ratio of total π - to π + multiplicities is not, the differential π - /π + ratio is sensitive to the density dependence of nuclear symmetry energy E sym (ρ). Our findings suggest that magnetic effects should be carefully considered in future studies of using the differential π - /π + ratio as a probe of the E sym (ρ) at suprasaturation densities.

Driving magnetic turbulence using flux ropes in a moderate guide field linear system

Science.gov (United States)

Brookhart, Matthew I.; Stemo, Aaron; Waleffe, Roger; Forest, Cary B.

2017-12-01

We present a series of experiments on novel, line-tied plasma geometries as a study of the generation of chaos and turbulence in line-tied systems. Plasma production and the injection scale for magnetic energy is provided by spatially discrete plasma guns that inject both plasma and current. The guns represent a technique for controlling the injection scale of magnetic energy. A two-dimensional (2-D) array of magnetic probes provides spatially resolved time histories of the magnetic fluctuations at a single cross-section of the experimental cylinder, allowing simultaneous spatial measurements of chaotic and turbulent behaviour. The first experiment shows chaotic fluctuations and self-organization in a hollow-current line-tied screw pinch. These dynamics is modulated primarily by the applied magnetic field and weakly by the plasma current and safety factor. The second experiment analyses the interactions of multiple line-tied flux ropes. The flux ropes all exhibit chaotic behaviour, and under certain conditions develop an inverse cascade to larger scales and a turbulent inertial range with magnetic energy ( ) related to perpendicular wave number ( \\bot $ ) as \\bot -2.5\\pm 0.5$ .

Magnetic Nanocomposite Cilia Energy Harvester

KAUST Repository

Khan, Mohammed Asadullah

2016-02-11

An energy harvester capable of converting low frequency vibrations into electrical energy is presented. The operating principle, fabrication process and output characteristics at different frequencies are discussed. The harvester is realized by fabricating an array of polydimethylsiloxane (PDMS) - iron nanowire nanocomposite cilia on a planar coil array. Each coil element consists of 14 turns and occupies an area of 600 μm x 600μm. The cilia are arranged in a 12x5 array and each cilium is 250 μm wide and 2 mm long. The magnetic characteristics of the fabricated cilia indicate that the nanowires are well aligned inside of the nanocomposite, increasing the efficiency of energy harvesting. The energy harvester occupies an area of 66.96 mm2 and produces an output r.m.s voltage of 206.47μV, when excited by a 40 Hz vibration of 1 mm amplitude.

Operation of multiple superconducting energy doubler magnets in series

International Nuclear Information System (INIS)

Kalbfleisch, G.; Limon, P.J.; Rode, C.

1977-01-01

In order to understand the operational characteristics of the Energy Doubler, a series of experiments were begun which were designed to be a practical test of running superconducting accelerator magnets in series. Two separate tests in which two Energy Doubler dipoles were powered in series are described. Of particular interest are the static losses of the cryostats and the behavior of the coils and cryostats during quenches. The results of the tests show that Energy Doubler magnets can be safely operated near their short sample limit, and that the various safety devices used are adequate to protect the coils and the cryostats from damage

Energy Autonomous Wireless Sensing System Enabled by Energy Generated during Human Walking

Science.gov (United States)

Kuang, Yang; Ruan, Tingwen; Chew, Zheng Jun; Zhu, Meiling

2016-11-01

Recently, there has been a huge amount of work devoted to wearable energy harvesting (WEH) in a bid to establish energy autonomous wireless sensing systems for a range of health monitoring applications. However, limited work has been performed to implement and test such systems in real-world settings. This paper reports the development and real-world characterisation of a magnetically plucked wearable knee-joint energy harvester (Mag-WKEH) powered wireless sensing system, which integrates our latest research progresses in WEH, power conditioning and wireless sensing to achieve high energy efficiency. Experimental results demonstrate that with walking speeds of 3∼7 km/h, the Mag-WKEH generates average power of 1.9∼4.5 mW with unnoticeable impact on the wearer and is able to power the wireless sensor node (WSN) with three sensors to work at duty cycles of 6.6%∼13%. In each active period of 2 s, the WSN is able to measure and transmit 482 readings to the base station.

Alignment of mapping system for magnet cyclotron DECY-13

International Nuclear Information System (INIS)

Idrus Abdul Kudus; Taufik; Kurnia Wibowo

2016-01-01

A cyclotron is composed of some main and specific components, such as magnet system, ion source, RF system and extractor. A magnet is one of important component in a cyclotron that serves as ion beam bending so the ion beam trajectory is circular. Magnet design should with the requirement of cyclotron that proton energy is 13 MeV. In the construction of the cyclotron magnet, a mapping tool of the magnetic field is required for analysis in shimming process in order to optimize the magnetic field. The magnetic field mapping process is carried out in the median plane of the magnet poles. The magnetic field mapping is carried out repeatedly during the shimming process. During this process, the mapping tool is possible to experience a shift or change in position, for that it is necessary to alignment in order to make sure that the probe is in the median plane of magnet poles and to ensure their positions are always the same on each repetition mapping. During this process, it is possible to experience a shift mapping tool or change the position, for this it is needed to process alignment to ensure the position of the probe is in the median plane magnetic poles and ensure their positions are always the same on each repetition mapping. Alignment on the mapping tool are the height position, zeroing tesla meter and two hall probe mapping. The parameters form the basis for magnetic field measurements based on the three elements: an alignment system on the engine mapping, mapping tool reference point and stage movement of x-y coordinates. Shifts occur due to change in elevation mapping tool table and center coordinates x and y in the mapping process. Changes made to shift mapping coordinates can be shifted as far as 1 to 2 mm for each hall probe in the x and y coordinates with altitude changes 0.05° mapping table and measurement of tesla meter changes in 0.002 T. (author)

CLIC project R&D studies: the magnet system for the 3 TEV

CERN Document Server

Modena, Michele

2017-01-01

This Note presents the R&D activities done and coordinated by TE-MSC Group on the magnetic system for the CLIC (Compact Linear Collider) project. The main aspects investigated are: the magnetic system definition, basic design for all magnets (i.e. a CLIC Magnet Catalogue), powering and cost evaluation, advanced design and prototyping for the most critical magnet variants. The CLIC layout here considered is the one for the highest collision energy of 3 TeV. This layout was the one studied in detail as baseline for the CLIC Conceptual Design Report that was released in 2012. This Note summarize the activities of about 6 years (2010-2016) done with the contribution of CERN staff (part-time), the contribution of some CERN Project Associates sponsored by the CLIC Project and in collaboration with STCF Daresbury Laboratory (UK).

Magnetism of metallacrown single-molecule magnets: From a simplest model to realistic systems

Science.gov (United States)

Pavlyukh, Y.; Rentschler, E.; Elmers, H. J.; Hübner, W.; Lefkidis, G.

2018-06-01

Electronic and magnetic properties of molecular nanomagnets are determined by competing energy scales due to the crystal field splitting, the exchange interactions between transition metal atoms, and relativistic effects. We present a comprehensive theory embracing all these phenomena based on first-principles calculations. In order to achieve this goal, we start from the FeNi4 cluster as a paradigm. The system can be accurately described on the ab initio level yielding all expected electronic states in a range of multiplicities from 1 to 9, with a ferromagnetic ground state. By adding the spin-orbit coupling between them we obtain the zero-field splitting. This allows to introduce a spin Hamiltonian of a giant spin model, which operates on a smaller energy scale. We compare the computed parameters of this Hamiltonian with the experimental and theoretical magnetic anisotropy energies of the monolayer Ni/Cu(001). In line with them, we find that the anisotropy almost entirely originates from the second-order spin-orbit coupling, the spin-spin coupling constitutes only a small fraction. Finally, we include the ligand atoms in our consideration. This component has a decisive role for the stabilization of molecules in experimental synthesis and characterization, and also substantially complicates the theory by bringing the superexchange mechanisms into play. Since they are higher-order effects involving two hopping matrix elements, not every theory can describe them. Our generalization of the corresponding perturbation theory substantiates the use of complete active space methods for the description of superexchange. At the same time, our numerical results for the {CuFe4} system demonstrate that the Goodenough-Kanamori rules, which are often used to determine the sign of these exchange interactions, cannot deliver quantitative predictions due to the interplay of other mechanisms, e. g., involving multicenter Coulomb integrals. We conclude by comparing ab initio values

High energy proton induced radiation damage of rare earth permanent magnet quadrupoles

Science.gov (United States)

Schanz, M.; Endres, M.; Löwe, K.; Lienig, T.; Deppert, O.; Lang, P. M.; Varentsov, D.; Hoffmann, D. H. H.; Gutfleisch, O.

2017-12-01

Permanent magnet quadrupoles (PMQs) are an alternative to common electromagnetic quadrupoles especially for fixed rigidity beam transport scenarios at particle accelerators. Using those magnets for experimental setups can result in certain scenarios, in which a PMQ itself may be exposed to a large amount of primary and secondary particles with a broad energy spectrum, interacting with the magnetic material and affecting its magnetic properties. One specific scenario is proton microscopy, where a proton beam traverses an object and a collimator in which a part of the beam is scattered and deflected into PMQs used as part of a diagnostic system. During the commissioning of the PRIOR (Proton Microscope for Facility for Antiproton and Ion Research) high energy proton microscope facility prototype at Gesellschaft für Schwerionenforschung in 2014, a significant reduction of the image quality was observed which was partially attributed to the demagnetization of the used PMQ lenses and the corresponding decrease of the field quality. In order to study this phenomenon, Monte Carlo simulations were carried out and spare units manufactured from the same magnetic material—single wedges and a fully assembled PMQ module—were deliberately irradiated by a 3.6 GeV intense proton beam. The performed investigations have shown that in proton radiography applications the above described scattering may result in a high irradiation dose in the PMQ magnets. This did not only decrease the overall magnetic strength of the PMQs but also caused a significant degradation of the field quality of an assembled PMQ module by increasing the parasitic multipole field harmonics which effectively makes PMQs impractical for proton radiography applications or similar scenarios.

Effect of magnetic field on the impurity binding energy of the excited ...

Indian Academy of Sciences (India)

The effect of external magnetic field on the excited state energies in a spherical quantum dot was studied. The impurity energy and binding energy were calculated using the variational method within the effective mass approximation and finite barrier potential. The results showed that by increasing the magnetic field, the ...

Effect of magnetic field on the impurity binding energy of the excited ...

Indian Academy of Sciences (India)

Abstract. The effect of external magnetic field on the excited state energies in a spher- ical quantum dot was studied. The impurity energy and binding energy were calculated using the variational method within the effective mass approximation and finite barrier potential. The results showed that by increasing the magnetic ...

Field Mapping System for Solenoid Magnet

Science.gov (United States)

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.

Electron energy recovery system for negative ion sources

International Nuclear Information System (INIS)

Dagenhart, W.K.; Stirling, W.L.

1982-01-01

An electron energy recovery system for negative ion sources is provided. The system, employs crossed electric and magnetic fields to separate the electrons from ions as they are extracted from a negative ion source plasma generator and before the ions are accelerated to their full kinetic energy. With the electric and magnetic fields oriented 90* to each other, the electrons are separated from the plasma and remain at approximately the electrical potential of the generator in which they were generated. The electrons migrate from the ion beam path in a precessing motion out of the ion accelerating field region into an electron recovery region provided by a specially designed electron collector electrode. The electron collector electrode is uniformly spaced from a surface of the ion generator which is transverse to the direction of migration of the electrons and the two surfaces are contoured in a matching relationship which departs from a planar configuration to provide an electric field component in the recovery region which is parallel to the magnetic field thereby forcing the electrons to be directed into and collected by the electron collector electrode. The collector electrode is maintained at a potential slightly positive with respect to the ion generator so that the electrons are collected at a small fraction of the full accelerating supply voltage energy

Magnetized Anisotropic Dark Energy Models in Barber’s Second Self-Creation Theory

Directory of Open Access Journals (Sweden)

D. D. Pawar

2014-01-01

Full Text Available The present paper deals with Bianchi type IX cosmological model with magnetized anisotropic dark energy by using Barber’s self-creation theory. The energy momentum tensor consists of anisotropic fluid with EoS parameter ω and a uniform magnetic field of energy density ρB. In order to obtain the exact solution we have assumed that dark energy components and the components of magnetic field interact minimally and obey the law of conservation of energy momentum tensors. We have also used the special law of variation for the mean generalized Hubble parameter and power law relation between scalar field and scale factor. Some physical and kinematical properties of the models have been discussed.

Analytical and computational study of magnetization switching in kinetic Ising systems with demagnetizing fields

DEFF Research Database (Denmark)

Richards, H.L.; Rikvold, P.A.

1996-01-01

particularly promising as materials for high-density magnetic recording media. In this paper we use analytic arguments and Monte Carlo simulations to quantitatively study the effects of the demagnetizing field on the dynamics of magnetization switching in two-dimensional, single-domain, kinetic Ising systems....... For systems in the weak-field ''stochastic region,'' where magnetization switching is on average effected by the nucleation and growth of a single droplet, the simulation results can be explained by a simple model in which the free energy is a function only of magnetization. In the intermediate......-field ''multidroplet region,'' a generalization of Avrami's law involving a magnetization-dependent effective magnetic field gives good agreement with the simulations. The effects of the demagnetizing field do not qualitatively change the droplet-theoretical picture of magnetization switching in highly anisotropic...

Ultrahigh energy nuclei propagation in a structured, magnetized universe

International Nuclear Information System (INIS)

Armengaud, Eric; Sigl, Guenter; Miniati, Francesco

2005-01-01

We compare the propagation of iron and proton nuclei above 10 19 eV in a structured Universe with source and magnetic field distributions obtained from a large-scale structure simulation and source densities ∼10 -5 Mpc -3 . All relevant cosmic ray interactions are taken into account, including photo-disintegration and propagation of secondary products. Iron injection predicts spectral shapes different from proton injection which disagree with existing data below ≅30 EeV. Injection of light nuclei or protons must therefore contribute at these energies. However, at higher energies, existing data are consistent with injection of pure iron with spectral indices between ∼2 and ∼2.4. This allows a significant recovery of the spectrum above ≅100 EeV, especially in the case of large deflections. Significant autocorrelation and anisotropy, and considerable cosmic variance are also predicted in this energy range. The mean atomic mass fluctuates considerably between different scenarios. At energies below 60 EeV, if the observed A > or approx. 35, magnetic fields must have a negligible effect on propagation. At the highest energies the observed flux will be dominated by only a few sources whose location may be determined by next generation experiments to within 10-20 deg. even if extra-galactic magnetic fields are important

Conceptual design study of the K-DEMO magnet system

Energy Technology Data Exchange (ETDEWEB)

Kim, Keeman, E-mail: kkeeman@nfri.re.kr [National Fusion Research Institute, 169-148 Gwahak-ro, Daejeon 305-806 (Korea, Republic of); Oh, Sangjun; Park, Jong Sung; Lee, Chulhee; Im, Kihak; Kim, Hyung Chan; Lee, Gyung-Su [National Fusion Research Institute, 169-148 Gwahak-ro, Daejeon 305-806 (Korea, Republic of); Neilson, George; Brown, Thomas; Kessel, Charles; Titus, Peter; Zhai, Yuhu [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States)

2015-10-15

Highlights: • Perform a preliminary conceptual study for a steady-state Korean DEMO reactor. • Present a preliminary design of TF (toroidal field) magnet. • Present a preliminary design of CS (central solenoid) magnet. • Present a preliminary design of PF (toroidal field) magnet. - Abstract: As the ITER is being constructed, there is a growing anticipation for an earlier realization of fusion energy. A major design philosophy for the initiated conceptual design study for a steady-state Korean fusion demonstration reactor (K-DEMO) is engineering feasibility. A two-staged development plan is envisaged. K-DEMO is designed not only to demonstrate a net electricity generation and a self-sustained tritium cycle, but also to be used, in its initial stage, as a component test facility. Then, in its second stage, a major upgrade is carried out by replacing in-vessel components in order to show a net electricity generation on the order of 500 MWe. After a thorough 0-D system analysis, the major radius and minor radius are chosen to be 6.8 m and 2.1 m, respectively. In order to minimize wave deflection, a top-launch high frequency (>200 GHz) electron cyclotron current drive (ECCD) system will be the key system for the current profile control. For matching the high frequency ECCD, a high toroidal field (TF) is required and can be achieved by using high current density Nb{sub 3}Sn superconducting conductor. The peak magnetic field reaches to 16 T with the magnetic field at the plasma center above 7 T. Key features of the K-DEMO magnet system include the use of two TF coil winding packs, each of a different conductor design, to reduce the construction cost and save the space for the magnet structure material.

Conceptual design study of the K-DEMO magnet system

International Nuclear Information System (INIS)

Kim, Keeman; Oh, Sangjun; Park, Jong Sung; Lee, Chulhee; Im, Kihak; Kim, Hyung Chan; Lee, Gyung-Su; Neilson, George; Brown, Thomas; Kessel, Charles; Titus, Peter; Zhai, Yuhu

2015-01-01

Highlights: • Perform a preliminary conceptual study for a steady-state Korean DEMO reactor. • Present a preliminary design of TF (toroidal field) magnet. • Present a preliminary design of CS (central solenoid) magnet. • Present a preliminary design of PF (toroidal field) magnet. - Abstract: As the ITER is being constructed, there is a growing anticipation for an earlier realization of fusion energy. A major design philosophy for the initiated conceptual design study for a steady-state Korean fusion demonstration reactor (K-DEMO) is engineering feasibility. A two-staged development plan is envisaged. K-DEMO is designed not only to demonstrate a net electricity generation and a self-sustained tritium cycle, but also to be used, in its initial stage, as a component test facility. Then, in its second stage, a major upgrade is carried out by replacing in-vessel components in order to show a net electricity generation on the order of 500 MWe. After a thorough 0-D system analysis, the major radius and minor radius are chosen to be 6.8 m and 2.1 m, respectively. In order to minimize wave deflection, a top-launch high frequency (>200 GHz) electron cyclotron current drive (ECCD) system will be the key system for the current profile control. For matching the high frequency ECCD, a high toroidal field (TF) is required and can be achieved by using high current density Nb_3Sn superconducting conductor. The peak magnetic field reaches to 16 T with the magnetic field at the plasma center above 7 T. Key features of the K-DEMO magnet system include the use of two TF coil winding packs, each of a different conductor design, to reduce the construction cost and save the space for the magnet structure material.

Optimizing Energy Conversion: Magnetic Nano-materials

Science.gov (United States)

McIntyre, Dylan; Dann, Martin; Ilie, Carolina C.

2015-03-01

We present herein the work started at SUNY Oswego as a part of a SUNY 4E grant. The SUNY 4E Network of Excellence has awarded SUNY Oswego and collaborators a grant to carry out extensive studies on magnetic nanoparticles. The focus of the study is to develop cost effective rare-earth-free magnetic materials that will enhance energy transmission performance of various electrical devices (solar cells, electric cars, hard drives, etc.). The SUNY Oswego team has started the preliminary work for the project and graduate students from the rest of the SUNY 4E team (UB, Alfred College, Albany) will continue the project. The preliminary work concentrates on analyzing the properties of magnetic nanoparticle candidates, calculating molecular orbitals and band gap, and the fabrication of thin films. SUNY 4E Network of Excellence Grant.

Soft-error tolerance and energy consumption evaluation of embedded computer with magnetic random access memory in practical systems using computer simulations

Science.gov (United States)

Nebashi, Ryusuke; Sakimura, Noboru; Sugibayashi, Tadahiko

2017-08-01

We evaluated the soft-error tolerance and energy consumption of an embedded computer with magnetic random access memory (MRAM) using two computer simulators. One is a central processing unit (CPU) simulator of a typical embedded computer system. We simulated the radiation-induced single-event-upset (SEU) probability in a spin-transfer-torque MRAM cell and also the failure rate of a typical embedded computer due to its main memory SEU error. The other is a delay tolerant network (DTN) system simulator. It simulates the power dissipation of wireless sensor network nodes of the system using a revised CPU simulator and a network simulator. We demonstrated that the SEU effect on the embedded computer with 1 Gbit MRAM-based working memory is less than 1 failure in time (FIT). We also demonstrated that the energy consumption of the DTN sensor node with MRAM-based working memory can be reduced to 1/11. These results indicate that MRAM-based working memory enhances the disaster tolerance of embedded computers.

ICENES '91:Sixth international conference on emerging nuclear energy systems

International Nuclear Information System (INIS)

1991-01-01

This document contains the program and abstracts of the sessions at the Sixth International Conference on Emerging Nuclear Energy Systems held June 16--21, 1991 at Monterey, California. These sessions included: The plenary session, fission session, fission and nonelectric session, poster session 1P; (space propulsion, space nuclear power, electrostatic confined fusion, fusion miscellaneous, inertial confinement fusion, μ-catalyzed fusion, and cold fusion); Advanced fusion session, space nuclear session, poster session 2P, (nuclear reactions/data, isotope separation, direct energy conversion and exotic concepts, fusion-fission hybrids, nuclear desalting, accelerator waste-transmutation, and fusion-based chemical recycling); energy policy session, poster session 3P (energy policy, magnetic fusion reactors, fission reactors, magnetically insulated inertial fusion, and nuclear explosives for power generation); exotic energy storage and conversion session; and exotic energy storage and conversion; review and closing session

A system for measuring the energy spread of an accelerated beam

International Nuclear Information System (INIS)

Wilkerson, J.F.; Ludwig, E.J.; Clegg, T.B.; Anderson, R.E.

1987-01-01

A system has been implemented to monitor directly the energy spread of analyzed beams from a tandem electrostatic accelerator. The dispersion of a deflection magnet in the beam handling system is used to transform the energy distribution into a spatial distribution, which then is measured by electrostatically sweeping the spatially extended beam across a narrow slit. (orig.)

Ideal of the perfect magnet-superconducting systems

International Nuclear Information System (INIS)

Shoaee, H.; Spencer, J.E.

1983-04-01

In this report, we study an iron-free, superconducting, elliptical coil quadrupole which has been proposed by General Atomics for use in the SLC final focus system. Beth has shown that such coils might provide a pure quadrupole field ignoring 3-D effects. Similarly, recent studies of rare earth permanent magnets have shown that, at least in principle, these magnets can also be made arbitrarily pure. Since similar claims can be made for conventional iron-core electromagnets either by demanding pure hyperbolic pole contours or using tricks, it is interesting to consider just how wide the gulf between principle and practice really is for each type of magnet and what it takes to bridge it (and where one is most likely to fall off). Here we consider only the superconducting option because its greater strength, variability and linearity make it potentially useful for the SLC and the low-beta insertions of the high energy storage rings such as PEP

Direct measurement of the impulse in a magnetic thrust chamber system for laser fusion rocket

Energy Technology Data Exchange (ETDEWEB)

Maeno, Akihiro; Yamamoto, Naoji; Nakashima, Hideki [Interdisciplinary Graduate School of Engineering Science, Kyushu University, 6-1 Kasuga-kouen, Kasuga, Fukuoka 816-8580 (Japan); Fujioka, Shinsuke; Johzaki, Tomoyuki [Institute of Laser Engineering, Osaka University, Suita, Osaka 565-087 (Japan); Mori, Yoshitaka [Graduate School for the Creation of New Photonics Industries, Hamamatsu, Shizuoka 431-1202 (Japan); Sunahara, Atsushi [Institute for Laser Technology, Suita, Osaka 565-087 (Japan)

2011-08-15

An experiment is conducted to measure an impulse for demonstrating a magnetic thrust chamber system for laser fusion rocket. The impulse is produced by the interaction between plasma and magnetic field. In the experiment, the system consists of plasma and neodymium permanent magnets. The plasma is created by a single-beam laser aiming at a polystyrene spherical target. The impulse is 1.5 to 2.2 {mu}Ns by means of a pendulum thrust stand, when the laser energy is 0.7 J. Without magnetic field, the measured impulse is found to be zero. These results indicate that the system for generating impulse is working.

Identification of the low-energy excitations in a quantum critical system

Directory of Open Access Journals (Sweden)

Tom Heitmann

2017-05-01

Full Text Available We have identified low-energy magnetic excitations in a doped quantum critical system by means of polarized neutron scattering experiments. The presence of these excitations could explain why Ce(Fe0.76Ru0.242Ge2 displays dynamical scaling in the absence of local critical behavior or long-range spin-density wave criticality. The low-energy excitations are associated with the reorientations of the superspins of fully ordered, isolated magnetic clusters that form spontaneously upon lowering the temperature. The system houses both frozen clusters and dynamic clusters, as predicted by Hoyos and Vojta [Phys. Rev. B 74, 140401(R (2006].

Electrical drives for direct drive renewable energy systems

CERN Document Server

Mueller, Markus

2013-01-01

Wind turbine gearboxes present major reliability issues, leading to great interest in the current development of gearless direct-drive wind energy systems. Offering high reliability, high efficiency and low maintenance, developments in these direct-drive systems point the way to the next generation of wind power, and Electrical drives for direct drive renewable energy systems is an authoritative guide to their design, development and operation. Part one outlines electrical drive technology, beginning with an overview of electrical generators for direct drive systems. Principles of electrical design for permanent magnet generators are discussed, followed by electrical, thermal and structural generator design and systems integration. A review of power electronic converter technology and power electronic converter systems for direct drive renewable energy applications is then conducted. Part two then focuses on wind and marine applications, beginning with a commercial overview of wind turbine drive systems and a...

Energy-extraction processes from a Kerr black hole immersed in a magnetic field. I. Negative-energy states

International Nuclear Information System (INIS)

Dhurandhar, S.V.; Dadhich, N.

1984-01-01

This is the first of two papers on the energy-extraction processes near a Kerr black hole immersed in a magnetic field. In this paper we shall consider the consequences of a dipole field extending to infinity matched on to a uniform field in the interior which contains the Kerr black hole. The magnetic fields considered are perturbative in nature. The matching of the fields is imperative owing to the ''no-hair theorem'' and the second law of black-hole physics. Two intriguing situations arising in this context are discussed, namely, (1) the second law of black-hole physics and (2) the law of conservation of energy in an energy-extraction process. At first sight both these laws seem to be violated. These issues arise basically because in the presence of the magnetic field there can exist negative-energy states even for L>0 particles. These issues get resolved by realizing that it is the sign of P/sub c/phi = L-eA/sub cphi/ and not L which determines a corotating or counterrotating orbit. It is also shown that negative-energy states can exist away from the horizon in the presence of either of the fields, the dipole and the uniform, thus favoring energy-extraction processes away from the black hole. This type of energy extraction is solely a consequence of the magnetic field. Also, a fairly detailed analysis of the effective-potential curves is provided, mainly relevant to the existence of negative energies and energy extraction. The formalism of the energy-extraction process will be considered in the second paper

Energy of Force-Free Magnetic Fields in Relation to Coronal Mass Ejections

International Nuclear Information System (INIS)

Choe, G.S.; Cheng, C.Z.

2002-01-01

In typical observations of coronal mass ejections (CMEs), a magnetic structure of a helmet-shaped closed configuration bulges out and eventually opens up. However, a spontaneous transition between these field configurations has been regarded to be energetically impossible in force-free fields according to the Aly-Sturrock theorem. The theorem states that the maximum energy state of force-free fields with a given boundary normal field distribution is the open field. The theorem implicitly assumes the existence of the maximum energy state, which may not be taken for granted. In this study, we have constructed force-free fields containing tangential discontinuities in multiple flux systems. These force-free fields can be generated from a potential field by footpoint motions that do not conserve the boundary normal field distribution. Some of these force-free fields are found to have more magnetic energy than the corresponding open fields. The constructed force-free configurations are compared with observational features of CME-bearing active regions. Possible mechanisms of CMEs are also discussed

Modular tokamak magnetic system

International Nuclear Information System (INIS)