Screening current induced magnetic field and stress in ultra-high-field magnets using REBCO coated conductors

2021 ◽  
Author(s):  
Yufan Yan ◽  
Yi Li ◽  
Ti-Ming Qu
Keyword(s):  
Magnetic Field ◽  
High Field ◽  
Large Scale ◽  
Field Experiments ◽  
Field Performance ◽  
Coated Conductors ◽  
Induced Magnetic Field ◽  
Ultra High Field ◽  
Mitigation Methods ◽  
Open Question

Abstract Rare-earth-based barium copper oxide (REBCO) coated conductors are promising candidates for the development of ultra-high-field (UHF) magnets, due to its high in-field performance, engineering current density, tensile strength and commercial availability. However, technological challenges pertaining to the large screening currents still remain. The major issues caused by the screening currents in REBCO conductors in UHF applications involve two aspects: the screening current induced magnetic field (SCF), and the screening current induced stress (SCS). In the past decades, extensive research has been devoted to the SCF, offering a variety of possible remedies. With latest advances in the construction and testing of UHF magnets, new observations of the SCF involving REBCO coils were reported. The SCS was identified in recent years and has raised growing concerns. The excessive and highly concentrated Lorentz force, rooted in the high magnetic field and the screening currents, poses threats to the mechanical strength of the REBCO coated conductors. The aim of this paper is to review recent research efforts in understanding and tackling the screening current related technological issues. For the SCF, we focus on the latest observations in high-field experiments and its various mitigation methods. For the SCS, we present recent studies including experimental characterizations, numerical modelling and possible countermeasures. It is still an open question to precisely predict SCS in large-scale HTS magnets. How to minimize the influence of SCF and SCS is one key technical issue for the design of future UHF magnets.

Analyses of the plastic deformation of coated conductors deconstructed from ultra-high field test coils

2020 ◽  
Vol 33 (9) ◽  
pp. 095012
Author(s):  
Xinbo Hu ◽  
Michael Small ◽  
Kwanglok Kim ◽  
Kwangmin Kim ◽  
Kabindra Bhattarai ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Field Test ◽  
High Field ◽  
Coated Conductors ◽  
Ultra High Field

scholarly journals Satellite observations of currents and waves in space plasmas

1988 ◽  
Vol 6 (3) ◽  
pp. 503-511 ◽  
Author(s):  
T. A. Potemra ◽  
M. J. Engebretson ◽  
L. J. Zanetti ◽  
R. E. Erlandson ◽  
P. F. Bythrow
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Geomagnetic Field ◽  
Large Scale ◽  
Field Experiments ◽  
Outer Space ◽  
Solar Wind Plasma ◽  
Field Configuration ◽  
The Earth ◽  
Field Lines

When viewed from outer space, the earth's magnetic field does not resemble a simple dipole, but is severely distorted into a comet-shaped configuration by the continuous flow of solar wind plasma. A complicated system of currents flows within this distorted magnetic field configuration called the ‘magnetosphere’ (See figure 1). For example, the compression of the geomagnetic field by the solar wind on the dayside of the earth is associated with a large-scale current flowing across the geomagnetic field lines, called the ‘Chapman-Ferraro’ or magnetopause current. The magnetospheric system includes large-scale currents that flow in the ‘tail’, the ring current that flows at high altitudes around the equator of the earth, field-aligned ‘Birkeland’ currents that flow along geomagnetic field lines into and away from the two auroral regions, and a complex system of currents that flows completely within the layers of the ionosphere, the earth's ionized atmosphere. The intensities of these various currents reach millions of amperes and are closely related to solar activity. The geomagnetic field lines can also oscillate, like giant vibrating strings, at specified resonant frequencies. The effects of these vibrations, sometimes described as ‘standing Alfvén waves’, have been observed on the ground in magnetic field recordings dating back to the beginning of the century. Observations of currents and waves with satellite-borne magnetic field experiments have provided a new perspective on the complicated plasma processes that occur in the magnetosphere. Some of the new observations are described here.

On possible origins of relatively short-term variations in the solar structure

1990 ◽  
Vol 330 (1615) ◽  
pp. 627-640 ◽  
Keyword(s):  
Magnetic Field ◽  
Solar Cycle ◽  
Large Scale ◽  
Convection Zone ◽  
Thermal Structure ◽  
Latitudinal Distribution ◽  
Short Term ◽  
The Earth ◽  
Total Luminosity ◽  
Open Question

The general large-scale redistribution of magnetic field over the solar cycle is possibly associated with an overall variation of thermal structure of the convection zone, which modulates not only the total luminosity but also the latitudinal distribution of radiative flux, thereby modifying the irradiance of the Earth. Whether the cause of this variation lies within the convection zone or is more deeply seated is still an open question.

scholarly journals Depth of origin of ocean-circulation-induced magnetic signals

2018 ◽  
Vol 36 (1) ◽  
pp. 167-180 ◽  
Author(s):  
Christopher Irrgang ◽  
Jan Saynisch-Wagner ◽  
Maik Thomas
Keyword(s):  
Magnetic Field ◽  
Ocean Circulation ◽  
Large Scale ◽  
Ocean Basin ◽  
Ocean Currents ◽  
Induced Magnetic Field ◽  
Electric Currents ◽  
Regional Patterns ◽  
Motional Induction ◽  
Different Depths

Abstract. As the world ocean moves through the ambient geomagnetic core field, electric currents are generated in the entire ocean basin. These oceanic electric currents induce weak magnetic signals that are principally observable outside of the ocean and allow inferences about large-scale oceanic transports of water, heat, and salinity. The ocean-induced magnetic field is an integral quantity and, to first order, it is proportional to depth-integrated and conductivity-weighted ocean currents. However, the specific contribution of oceanic transports at different depths to the motional induction process remains unclear and is examined in this study. We show that large-scale motional induction due to the general ocean circulation is dominantly generated by ocean currents in the upper 2000 m of the ocean basin. In particular, our findings allow relating regional patterns of the oceanic magnetic field to corresponding oceanic transports at different depths. Ocean currents below 3000 m, in contrast, only contribute a small fraction to the ocean-induced magnetic signal strength with values up to 0.2 nT at sea surface and less than 0.1 nT at the Swarm satellite altitude. Thereby, potential satellite observations of ocean-circulation-induced magnetic signals are found to be likely insensitive to deep ocean currents. Furthermore, it is shown that annual temporal variations of the ocean-induced magnetic field in the region of the Antarctic Circumpolar Current contain information about sub-surface ocean currents below 1000 m with intra-annual periods. Specifically, ocean currents with sub-monthly periods dominate the annual temporal variability of the ocean-induced magnetic field. Keywords. Electromagnetics (numerical methods) – geomagnetism and paleomagnetism (geomagnetic induction) – history of geophysics (transport)

scholarly journals Enhancing magnetic resonance imaging with contrast agents for ultra-high field strengths

The Analyst ◽  
2014 ◽  
Vol 139 (18) ◽  
pp. 4401-4410 ◽  
Author(s):  
Akhila N. W. Kuda-Wedagedara ◽  
Matthew J. Allen
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Field ◽  
Magnetic Resonance ◽  
Contrast Agents ◽  
High Magnetic Field ◽  
High Field ◽  
Resonance Imaging ◽  
Ultra High Field ◽  
New Strategies ◽  
Field Strengths

New strategies for contrast agents enable effective magnetic resonance imaging at ultra-high magnetic field strengths.

Mîcromagnetic Modeling of the Behavior of Magnetostrictive Films under Stress

2003 ◽  
Vol 785 ◽  
Author(s):  
Y. C. Shu ◽  
J. H. Yen
Keyword(s):  
Magnetic Field ◽  
Large Scale ◽  
Magnetic Domain ◽  
Conventional Approach ◽  
Intrinsic Stress ◽  
Induced Magnetic Field ◽  
Kinematic Constraint ◽  
Strain Compatibility ◽  
Micromagnetic Modeling ◽  
Simulation Results

ABSTRACTWe study the effect of stress on the behavior of magnetostrictive films. Our approach is different from the conventional one which neglects the strain compatibility. Here, we include the kinematic constraint in our micromagnetic model and proposed to use the average to calculate the stress-induced magnetic field. The analytic formulation of magnetostrictive energy is derived which enables us to perform simulation at a large scale with few iteration steps. The simulation results show that the conventional approach is insufficient to predict magnetic domain patterns for materials with large magnetostriction, and the effect of intrinsic stress cannot be neglected.

scholarly journals Nanoscale analysis of superconducting Fe(Se,Te) epitaxial thin films and relationship with pinning properties

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mario Scuderi ◽  
Ilaria Pallecchi ◽  
Antonio Leo ◽  
Angela Nigro ◽  
Gaia Grimaldi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Large Scale ◽  
Mean Free Path ◽  
Coated Conductors ◽  
Epitaxial Thin Films ◽  
Field Orientation ◽  
Pinning Centers ◽  
The Magnetic Field ◽  
Pinning Properties

AbstractThe process of developing superconducting materials for large scale applications is mainly oriented to optimize flux pinning and the current carrying capability. A powerful approach to investigate pinning properties is to combine high resolution imaging with transport measurements as a function of the magnetic field orientation, supported by a pinning modelling. We carry out Transmission Electron Microscopy, Electron Energy Loss Spectroscopy and critical current measurements in fields up to 16 T varying the angle between the field and c-axis of Fe(Se,Te) epitaxial thin films deposited on CaF2 substrates. We find evidence of nanoscale domains with different Te:Se stoichiometry and/or rotated and tilted axes, as well as of lattice distortions and two-dimensional defects at the grain boundaries. These elongated domains are tens of nm in size along the in-plane axes. We establish a correlation between these observed microstructural features and the pinning properties, specifically strongly enhanced pinning for the magnetic field oriented in-plane and pinning emerging at higher fields for out-of-plane direction. These features can be accounted for within a model where pinning centers are local variations of the critical temperature and local variations of the mean free path, respectively. The identification of all these growth induced defects acting as effective pinning centers may provide useful information for the optimization of Fe(Se,Te) coated conductors.

Sign in / Sign up

Export Citation Format

Share Document