Faculty Profiles - UEDA Hiroshi

Papers - UEDA Hiroshi

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Experiment and numerical simulation of the combined effect of winding, cool-down, and screening current induced stresses in REBCO coils Reviewed International journal

Hiroshi Ueda, Hideaki Maeda, Yu Suetomi, Yoshinori Yanagisawa

Superconductor Science and Technology 35 ( 5 ) 054001 - 054001 2022.5

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：{IOP} Publishing

This paper overviews the combined effects of winding, cool-down, and screening current-induced stresses in REBCO coils. First, a simulation method to model the circumferential stress modification effect due to the screening-current is overviewed. The simulation includes coil winding, cooling down, and coil charge up to the operating current. Second, we will compare the numerical simulation results with the experimental results. The numerical simulations for a dry coil and an epoxy impregnated coil agree well with the experimental results. Third, the enhanced circumferential stress did not degrade the performance of a dry winding REBCO coil, but the improved increased compressive stress buckled the coil structure. Finally, it is demonstrated that epoxy impregnation has beneficial effects in reducing the stress modification effect. However, the circumferential stress is enormously enhanced at the coil ends, sometimes resulting in degradation of the coil performance.

DOI： 10.1088/1361-6668/ac4b9e

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Numerical evaluation of the deformation of REBCO pancake coil, considering winding tension, thermal stress, and screening-current-induced stress Reviewed International journal

Hiroshi Ueda, Yuta Awazu, Keisuke Tokunaga, SeokBeom Kim

Superconductor Science and Technology 34 ( 2 ) 24003 - 24003 2021.2

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：IOP Publishing

In recent years, the applications of high-field REBa2CuOy (REBCO) coils have remarkably progressed towards NMR MRIs, accelerators, and other such devices. In a REBCO coil, the magnetic field due to the screening current is generated in the direction opposite to the field by the transport current, thus reducing the magnetic field, deteriorating the field homogeneity, and affecting the time stability of the magnetic field. Recently, the additional force and stress due to the screening current (referred to as screening-current-induced stress) has become a topic of concern. The screening current results in non-uniform current distributions in the REBCO tape. Therefore, the distribution of electromagnetic force in REBCO coils differs from that during the designing of the coil, assuming that the current flow in the tape is uniform. Thus, there is the possibility that the existence of screening current is a serious problem in the mechanical design of REBCO coils. In this study, we evaluate the electromagnetic force and stress due to the screening current by using the developed numerical simulation code for the electromagnetics and stress. We discuss the winding tension, thermal and electromagnetic stresses, and mechanical strength structure of the REBCO coil.

DOI： 10.1088/1361-6668/abcd24

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Other Link： https://iopscience.iop.org/article/10.1088/1361-6668/abcd24/pdf

Conceptual Design of Compact HTS Cyclotron for RI Production Reviewed International journal

Hiroshi Ueda, Atsushi Ishiyama, So Noguchi, Tomonori Watanabe, Shigeo Nagaya, Jun Yoshida, Mitsuhiro Fukuda

IEEE Transactions on Applied Superconductivity 29 ( 5 ) 4101105 2019.8

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

In autumn 2017, the project "Quantum Innovation for Safe and Smart Society (QiSS)" was started in Program on Open Innovation Platform with Enterprises, Research Institute and Academia (OPERA) by Japan Science and Technology Agency (JST). One of the key issues of this project is the advancement of compact cyclotron and beam irradiation device for stable supply of short-lived radioisotope (RI). We proposed the air-core cyclotron using high-temperature superconducting (HTS) technology, named Skeleton Cyclotron, as high intensity compact cyclotron. Currently, we are carrying out a feasibility study on a variable-energy multi-particle Skeleton Cyclotron for RI production. In this paper, key issues in HTS magnet technologies for Skeleton Cyclotron and the preliminary conceptual design of variable-energy multi-particle Skeleton Cyclotron are reported.

DOI： 10.1109/TASC.2019.2903538

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Numerical Simulation on Magnetic Field Generated by Screening Current in 10-T-Class REBCO Coil Reviewed International journal

Hiroshi Ueda, Yohei Imaichi, Tao Wang, Atsushi Ishiyama, So Noguchi, Sadanori Iwai, Hiroshi Miyazaki, Taizo Tosaka, Shunji Nomura, Tsutomu Kurusu, Shinichi Urayama, Hidenao Fukuyama

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 26 ( 4 ) 4701205 2016.6

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

In a REBCO superconducting magnet for magnetic resonance imaging (MRI) applications, the large screening current induced by a magnetic field perpendicular to the winding tape is a serious problem: it generates irregular magnetic field that deteriorates the spatial field homogeneity and temporal field stability in MRI applications. Therefore, we need to estimate the magnetic field generated by the screening current using electromagnetic field analysis to design and develop a REBCO magnet that generates highly accurate and stable magnetic field. Therefore, to examine the influence of the magnetic field generated by the screening current, we constructed cryocooler-cooled small bore-coil stacked pancake REBCO coils with an inner diameter of 50 mm. This coil generates a magnetic field of 10 T at the center. In this study, we report the evaluation of the current distribution and magnetic field in the REBCO coil using the developed 3-D numerical simulation code for electromagnetic field analysis in a REBCO tape using the finite-element method and fast multipole method. The numerical results agree well with the experimental results. Furthermore, we discuss the current distribution in the REBCO tape and the spatial and temporal behavior of the magnetic field on the basis of the results of the experiments and numerical simulation.

DOI： 10.1109/TASC.2016.2535965

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Performance of Filters in Medical Protein Separation System Using Superconducting Magnet Reviewed International journal

Hiroshi Ueda, Koh Agatsuma, Mitsuho Furuse, Shuichiro Fuchino, Kazuhiro Kajikawa, Yasuharu Kamioka, Tomohiro Iitsuka, Shuichi Nakamura

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 24 ( 3 ) 3700405 2014.6

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

Medical proteins such as monoclonal antibodies or immunoglobulin are important as medicine for cancer and other uses. Today, we can easily sort and analyze medical proteins using various types of commercially available affinity magnetic beads. However, separation systems for these medical proteins have a very low separation rate, and the cost of the product is extremely high. We successfully developed a high gradient magnetic separation system using a cryocooler-cooled low-temperature superconducting magnet and conducted experiments on separating affinity magnetic nanobeads. Our system demonstrated very high separation efficiency and can achieve low costs with a large production rate compared to systems now used in this field. The design of a filter to trap and recover the nanobeads is important to this application. In order to achieve a filter with a high trapping ratio of magnetic beads, the parameters need to be optimized because the ratio depends on the dimensions and arrangement of the filter made of fine magnetic metal fibers. In this study, we investigated the performance of filters in the high gradient magnetic separation system. The test results show 97.8% of the magnetic nanobeads in pure water were captured, and 94.1% of the total beads were collected.

DOI： 10.1109/TASC.2013.2290374

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Evaluation of Screening Current-Induced Field Generated by No-Insulation REBCO Coil System for Multi-Frequency ECR Ion Source

Ao Shimada, Atsushi Ishiyama, Tsun Him Chong, Mitsuhiro Fukuda, So Noguchi, Hiroshi Ueda

IEEE Transactions on Applied Superconductivity 2025.8

Design of Multiple REBCO Sector Coils for Improving Focusing Force in Skeleton Cyclotron for Cancer Therapy

Aoi Yamashita, Ryota Inoue, SeokBeom Kim, So Noguchi, Tomonori Watanabe, Mitsuhiro Fukuda, Atsushi Ishiyama, Hiroshi Ueda

IEEE Transactions on Applied Superconductivity 2025.8

Electric Power Transmission Characteristics of WPT System Using HTS and Copper Coils Coupled With Magnetic Material

Ryota Inoue, Takahiro Iwamoto, Hiroshi Ueda, SeokBeom Kim

IEEE Transactions on Applied Superconductivity 2025

Evaluation of Thermal Stability of 1/2-Scale Demonstration System of Skeleton Cyclotron for Cancer Therapy

Takuto Hiura, Taro Nakamura, Atsushi Ishiyama, So Noguchi, Hiroshi Ueda

IEEE Transactions on Applied Superconductivity 2025

Local Stress Due to Screening Current of No-Insulation Non-Circular REBCO Coil in Half-Scale Coil System of Skeleton Cyclotron

Hiroshi Ueda, Aoi Yamashita, Ryota Inoue, SeokBeom Kim, So Noguchi, Tomonori Watanabe, Mitsuhiro Fukuda, Atsushi Ishiyama

IEEE Transactions on Applied Superconductivity 2025

Study on Protection Method for HTS Coils With AC Current in Wireless Power Transmission System

Ryota Inoue, Haruki Komoda, Hiroshi Ueda, SeokBeom Kim

IEEE Transactions on Applied Superconductivity 2025

Energization Current Waveform to Reduce Irregular Magnetic Fields in Multi-Stacked No-Insulation REBCO Coil Systems

Muku Yoshifuji, Ao Shimada, Atsushi Ishiyama, So Noguchi, Hiroshi Ueda

IEEE Transactions on Applied Superconductivity 2025

Evaluation of the Thermal Stability of REBCO Pancake Coils With Partially Noncontact Areas Between Winding Turns Reviewed International journal

Kazuki Amano, Taro Nakamura, Nodoka Terauchi, Atsushi Ishiyama, Hiroshi Ueda, So Noguchi