MT29 Abstracts and Technical Program

Session

Thu-Af-Po.04 - Screening Currents and Shimming

3 Jul 2025, 14:00

Ensemble Ballroom, Level 2

Conveners

Thu-Af-Po.04 - Screening Currents and Shimming

• Bárbara Santos (Rio de Janeiro State University)
• Tatsushi Nakamoto (KEK)

151. Thu-Af-Po.04-01: A Study on Determining Charging Current Waveform to Reduce Screening Current Induced Field in HTS NMR Magnets

Boun Seo

03/07/2025, 14:00

Poster

In this paper, we present a method for determining the appropriate charging current waveform to mitigate the screening current-induced field (SCF) in an NMR class high temperature superconducting (HTS) magnet. Screening currents have been observed to cause magnetic field drift in NMR class HTS magnets, leading to a degradation in performance. To address this performance degradation, various...

360. Thu-Af-Po.04-02: Electromagnetic Investigation of Shielding Effect of NI REBCO Windings for Screening Current Reduction

Takanobu Mato

03/07/2025, 14:00

Poster

The no-insulation (NI) technology is a powerful technique toward very high field generation over 40 T. The National High Magnetic Field Laboratory (NHMFL), in 2017, successfully generated a field of 45.5 T, which is the world record for the DC field [1]. The success is attributed to the use of rare-earth barium copper oxide (REBCO) and the NI technology. REBCO conductors can withstand a very...

150. Thu-Af-Po.04-03: Proof-of-Concept of a Reinforcement-Learning- Based RT shimming technique for HTS magnets

Jaehyeok Han

03/07/2025, 14:00

Poster

We report a newly developed room-temperature (RT) shimming method for high-temperature superconducting (HTS) magnets employing a deep Q-network (DQN), a type of reinforcement learning theory. With only one training session, the shimming control system (agent) learns how to improve the spatial field homogeneity of an HTS magnet and quickly implements the actual shimming process even under...

437. Thu-Af-Po.04-04: Active shimming method for a 7T MRI superconducting magnet

Haoran Chen (School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China)

03/07/2025, 14:00

Poster

In the design of ultrahigh field magnetic resonance imaging (MRI) superconducting magnets, it typically requires a high homogeneous magnetic field in the diameter of spherical volume (DSV) to obtain high quality image. Spherical harmonic based B0 shimming relies significantly on the fitting process, which can be computationally demanding, especially when handling a large number of shim coils....