| 研究開始時の研究の概要 |
Using High Temperature Superconductors, especially the Rare-EarthBaCuO coated conductors, makes it possible to build magnets producing very high magnetic field(more than 25 T) with low operation cost. The behaviour of magnets using such conductors is however difficult to predict in details, especially in terms of field homogeneity, which limits their potential use. The aim of this project is to develop our understanding of the transient electromagnetic behaviour of these REBCO magnets and develop measurements and active control technique to reach the higher field quality that users require.
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| 研究実績の概要 |
In the first year of the project, the numerical model evaluating precisely the electromagnetic behavior of REBCO winding was developed, and experimental validations confirmed its accuracy on small scale test pancakes.
In this last year detailed comparison were conducted on test coils to understand the relationship between current distribution dynamics, voltage, and generated field, which lead to the publication of a joint paper in collaboration with Grenoble CNRS.
Then, the development was continued with the help of a more powerful workstation, which made it possible to simulate one half of a full-size very high field insert, like the one developed at HFLSM in the framework of the 30T CSM project.
The accuracy of the model predictions on large scale systems will have to be confirmed once the magnet is tested in the next years, but already significant insights were obtained in terms of field homogeneity, field drift and AC losses for that magnet. This pave the way for an efficient control of the magnet, and the compensation of field drift in particular.
In parallel, the project evolved toward calculating the consequences of inhomogenous current distribution in REBCO conductors in terms of mechanical stress. This development was triggered by rising concerns in the Applied Superconductivity community about the risk posed by stress concentrations in REBCO windings. The model developed in the course of this project could be readily adapted to provide insight on that topic. This development lead to an invited oral presentation at international conference CEC-ICMC in July 2021.
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