TY - JOUR

T1 - Uniform Magnetic Field between Face-to-Face HTS Bulk Magnets Combining Concave and Convex Magnetic Field Distributions

AU - Oka, T.

AU - Takahashi, Y.

AU - Yaginuma, S.

AU - Ogawa, J.

AU - Fukui, S.

AU - Sato, T.

AU - Yokoyama, K.

AU - Nakamura, T.

N1 - Publisher Copyright:
© 2016 The Authors.

PY - 2016

Y1 - 2016

N2 - The authors have been attempting to obtain the uniform magnetic field distribution in the space between the face-to-face HTS bulk magnets. The magnetic poles containing the HTS bulk magnets are usually characterized as non-uniform magnetic field distribution. Since the distributions show the conical or convex shapes, it is difficult to obtain the uniform magnetic field spaces even when the magnetic poles would be placed face-to-face. The authors have modified the shape of the distribution of one-side magnetic pole by attaching an iron plate on the surface, and formed the concave magnetic field distribution on the pole surface. The steep concave or convex distributions at each pole surface change to be flat with increasing distance from the pole surface. After the experimental result recording the best uniformity of 358 ppm by combining the concave and convex field distributions face-to-face, we attempted to simulate the feasible performance in this configuration. In the numerical simulation, the concave field distribution modified by attaching an imaginary spiral coil on the pole surface was coupled with the original convex field. We succeeded in obtaining the best uniformity of 30 ppm at 1.1 T in 4 x 4 mm2 x-y plane at 7 mm distant from the pole surface in the gap of 30 mm. This result suggests that the concave and convex magnetic field distributions compensate the field uniformity with each other with keeping the magnetic field strength in the gap, and also suggests the novel compact NMR/MRI devices in the future.

AB - The authors have been attempting to obtain the uniform magnetic field distribution in the space between the face-to-face HTS bulk magnets. The magnetic poles containing the HTS bulk magnets are usually characterized as non-uniform magnetic field distribution. Since the distributions show the conical or convex shapes, it is difficult to obtain the uniform magnetic field spaces even when the magnetic poles would be placed face-to-face. The authors have modified the shape of the distribution of one-side magnetic pole by attaching an iron plate on the surface, and formed the concave magnetic field distribution on the pole surface. The steep concave or convex distributions at each pole surface change to be flat with increasing distance from the pole surface. After the experimental result recording the best uniformity of 358 ppm by combining the concave and convex field distributions face-to-face, we attempted to simulate the feasible performance in this configuration. In the numerical simulation, the concave field distribution modified by attaching an imaginary spiral coil on the pole surface was coupled with the original convex field. We succeeded in obtaining the best uniformity of 30 ppm at 1.1 T in 4 x 4 mm2 x-y plane at 7 mm distant from the pole surface in the gap of 30 mm. This result suggests that the concave and convex magnetic field distributions compensate the field uniformity with each other with keeping the magnetic field strength in the gap, and also suggests the novel compact NMR/MRI devices in the future.

KW - Bulk magnet

KW - NMR

KW - magnetic field distribution

KW - pulsed-field magnetization

KW - superconductor

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U2 - 10.1016/j.phpro.2016.04.019

DO - 10.1016/j.phpro.2016.04.019

M3 - Conference article

AN - SCOPUS:84994670386

SN - 1875-3884

VL - 81

SP - 45

EP - 48

JO - Physics Procedia

JF - Physics Procedia

T2 - 28th International Symposium on Superconductivity, ISS 2015

Y2 - 16 November 2015 through 18 November 2015

ER -