So Noguchi

The no-insulation (NI) winding technique drastically enhances the thermal stability of REBa <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</sub> (REBCO) coils. Even if a larger current than a critical current is carried in NI REBCO pancake

This paper describes an optimal design method for superconducting magnets wound with high temperature superconducting (HTS) tapes (e.g. Bi2223/Ag tapes). The properties of HTS tapes have been advancing and HTS magnets have been constructed and demonstrated. However, the HTS tapes have thermally different characteristics compared with the low temperature superconducting (LTS) wires. Therefore it is necessary to consider these characteristics of HTS tapes at the magnet design stage. We propose a n

Recently, the properties of high temperature superconducting (HTS) tapes have been in advance and HTS magnets have been constructed and demonstrated. However, the HTS tapes have thermal different characteristics compared with the low temperature superconducting (LTS) wires. Moreover, Bi2223/Ag tapes and YBCO coated conductors have the different properties about the dependence on the degree of external magnetic field. Therefore it is necessary to consider these characteristics of HTS tapes at mag

Abstract Since the screening current (SC) in rare earth-barium-copper-oxide (REBCO) coated conductor (CC) generates an undesired magnetic field, it must be accurately estimated, especially for magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR). Moreover, in recent years, it was pointed out that the screening current enhanced the stress/strain in REBCO CC, when an REBCO magnet was operated as an insert under an ultrahigh magnetic field. The previously reported SC simulation met

Recently, the properties of high temperature superconducting tapes have been in advance and high temperature superconducting magnets have been constructed and demonstrated. However, the high temperature superconducting tapes have different thermal characteristics compared with low temperature superconducting wires. Therefore, it is necessary to consider these characteristics of high temperature superconducting tapes at the magnet design stage. We proposed an optimal design method for superconduc

The MIT 1.3-GHz LTS/HTS NMR magnet is currently under development. The unique features of this magnet include a 3-nested formation for an 800-MHz REBCO insert (H800) and the no-insulation (NI) winding technique for H800 coils. Because when it is driven to the normal state, an NI REBCO magnet will respond electromagnetically, thermally, and mechanically that may result in permanent magnet damage, analysis of a quenching magnet is a key aspect of HTS magnet protection. We have developed a partial

Abstract The development of NMR/MRI REBa 2 Cu 3 O y (REBCO, RE = rare earth) magnets is happening all over the world. It has been found that screening current-induced magnetic fields (SCMFs) are a serious problem for NMR/MRI magnets wound with REBCO tapes. The reduction of SCMFs is strongly desired, and the estimation of SCMFs is also desired at the design stage of REBCO magnets. In order to evaluate a SCMF, a finite element method (FEM) or a boundary integration method is needed thus far, and a

A no-insulation winding technique for an NbTi superconducting coil is expected to improve its dynamic stability during charging or discharging. Experimental results, recently reported, demonstrated the charging stability enhancement of an NI coil. In an NI winding, an amount of current can bypass to adjacent wires to avoid the generation of a local hot spot and, as a result, the dynamic stability is improved. In spite of the potential technical merits of the NI technique, the charging responses

The turn-to-turn contact resistance (characteristic resistance) is a very important factor to a no-insulation (NI) (RE)Ba <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</sub> (REBCO) pancake coil. It characterizes the stability and chargin

Highly homogeneous and high-field superconducting magnets are difficult to design for optimal configuration, which has the minimum winding volume. In this paper, we propose an optimal design method utilizing a modified genetic algorithm to realize the minimum winding volume design for multi-section superconducting magnets. The detail of the algorithm and two examples of its application to three-section superconducting magnets are shown.

This paper describes an optimal design method for SMES coils wound with high temperature superconducting (HTS) tapes (e.g., Bi2223/Ag tapes). Recently, the properties of HTS tapes have advanced and HTS magnets have been constructed and demonstrated. However, the HTS tapes have different thermal characteristics compared with the low temperature superconducting (LTS) wires. Therefore, it is necessary to consider these characteristics of HTS tapes at magnet design stage. We propose an optimal desig

Abstract No-insulation (NI) and metal-insulation (MI) winding techniques are promising for enhancing the thermal stability of REBCO pancake coils, toward the practical use of nuclear magnetic resonance and magnetic resonance imaging systems. The NI and MI REBCO pancake coils showed high thermal stability in many over-current tests. However, a disadvantage is a charging delay due to low turn-to-turn contact resistance. Therefore, many researchers have tried to increase turn-to-turn contact resist

The characteristics of no-insulation high-temperature superconducting (HTS) manet is dominated by the magnitude of the turn-to-turn contact resistance. A few techniques have been proposed to increase the turn-to-turn contact resistance. The relation between the turn-to-turn contact resistance and the magnet stability has also been investigated in simulations. Although the turn-to-turn contact resistance measurement was only the sudden-discharging method before, we proposed a low-frequency-AC cur

No-insulation (NI) REBCO pancake coils show high thermal stability, however the charging delay is an issue. Hence, to improve the charging delay, it was proposed that a stainless steel (SUS) tape was cowound between turns, called “metal-as-insulation” or “metal-insulation (MI),” to increase the turn-to-turn contact resistivity. The MI technique could make the turn-to-turn contact resistivity approximately 50 times large compared to a conventional NI REBCO pancake coil. This paper reports a bypas

This paper describes an optimal design method for highly homogeneous superconducting magnet systems with a ferromagnetic shield. The presented design technique is a combination of the equivalent magnetization current method for the computation of the magnetic field problem, which includes nonlinear and saturated iron, and simulated annealing for solving the corresponding optimization problem. The equivalent magnetization current method is superior in estimating the field homogeneity of the cente