A Simple Method for Measurement of AC Losses in Superconducting Wires under Configuration of a Double-Layer Non-Inductive Coil
A Simple Method for Measurement of AC Losses in Superconducting Wires under Configuration of a Double-Layer Non-Inductive Coil
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双层无感线圈配置下超导线材交流损耗的简易测量方法
DOI：
10.1007/978-1-4757-9047-4_40
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
T. Kumano
中科院分区：
文献类型：
--
作者：
K. Funaki;K. Kajikawa;H. Tomiya;M. Nakamura;M. Iwakuma;S. Miyake;T. Kumano
我们用一个简单的拾取线圈测量了NbTi细丝在60赫兹横向磁场中的交流损耗。样品具有双层无感线圈的结构。在样品线圈的两端都安装了电位型抽头。在这种配置中，双层样品本身是测量交流损耗的拾取线圈。在这个过程中，我们可以通过一对电势抽头和一个外磁场拾取线圈的信号来近似估计两层之间侧面上的平均Pointing矢量。为了进行比较，我们用传统的带有同轴拾取线圈的电磁法和量热法测量了交流损耗。在后一种方法中，我们通过校准蒸发的氦气体量来获得等效交流损耗。在较宽的外加磁场幅值范围内，三种方法的交流损耗实验结果基本一致。我们还测量了样品线圈中的传输电流损耗，并与量热法的结果很好地吻合。此外，我们还讨论了该方法对更普遍类型的交流损耗测量的适用性。
We measured AC losses in superconducting wires with NbTi fine filaments exposed to a transverse magnetic field of 60 Hz by a simple pickup coil. The samples have configuration of a double-layer non-inductive coil. Potential taps were attached to both terminals of the sample coil. In this configuration, the double-layer sample itself is a pickup coil to measure the AC loss. In this procedure, we can approximately estimate an averaged Poynting’s vector on the side surface between the two layers by means of signals from a pair of the potential taps and a pickup coil for the external magnetic field. For comparison, we measured the AC losses both by a conventional electromagnetic method with coaxial pickup coils and by a calorimetric one. In the latter method, we obtain an equivalent AC loss by calibrating the amount of vaporized helium gas. Experimental results of the AC losses coincide with each other among the three methods in a wide range of the amplitude of external magnetic field. We also measured a transport-current loss in the sample coil and had a good agreement with results from the calorimetric method. Furthermore, we discuss the applicability of the proposed method to more universal types of AC loss measurement.