包含YBCO环的紧凑型核磁共振磁体中俘获场的时间增强。
Temporal Enhancement of Trapped Field in a Compact NMR Magnet Comprising YBCO Annuli.
作者信息
Hahn Seungyong, Kim Youngjae, Voccio John P, Song Jungbin, Bascuñán Juan, Tomita Masaru, Iwasa Yukikazu
机构信息
Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139 USA.
Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139 USA, and also with the Applied Superconductivity, Materials Technology Division, Railway Technical Research Institute (RTRI), Tokyo 185-8540, Japan.
出版信息
IEEE Trans Appl Supercond. 2014 Jun;24(3). doi: 10.1109/tasc.2013.2283226. Epub 2013 Sep 24.
Temporal "enhancement" of trapped fields was observed in the central region of a compact NMR magnet comprising a stack of 2800 YBCO "square" annuli (YP2800), field-cooled at 4.2 K. This paper presents an analytical model to simulate the trapped field enhancement in YP2800. First, based on an inverse calculation technique, the current distributions in the 560 5-plate modules of YP2800 were computed from the measured trapped field distribution. Then, YP2800 was modeled as a set of "three magnetically-coupled subcoils": the "bottom" coil (C, 140 modules); the "middle" coil (C, 280 modules); and the "top" coil (C, 140 modules). With the index resistance of each coil included, the circuit model shows that the average current in C "slowly" increases, induced by "fast" current decays in C and C. As a result, the center field in YP2800, dominated by the C currents, increases in time. The simulation agrees reasonably well with the measurement, which validates the analytical model.
在一个由2800个YBCO“方形”环（YP2800）堆叠而成、在4.2K下进行场冷的紧凑型核磁共振磁体的中心区域，观察到了俘获场的时间“增强”现象。本文提出了一个分析模型来模拟YP2800中俘获场的增强。首先，基于反演计算技术，根据测量的俘获场分布计算了YP2800的560个5板模块中的电流分布。然后，将YP2800建模为一组“三个磁耦合子线圈”：“底部”线圈（C，140个模块）；“中间”线圈（C，280个模块）；以及“顶部”线圈（C，140个模块）。考虑到每个线圈的电阻指数，电路模型表明，C中的平均电流由C和C中的“快速”电流衰减“缓慢”增加。结果，由C电流主导的YP2800中的中心场随时间增加。模拟结果与测量结果相当吻合，验证了分析模型的有效性。
Zotero 插件