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arXiv 1608.08378cond-mat.supr-con
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从HTS超导带的场电流-电压特性中提取超导体$J_c(B,θ)$场依赖性的无参数方法

A parameter-free method to extract the superconductor's $J_c(B,θ)$ field-dependence from in-field current-voltage characteristics of HTS tapes

Víctor M. R. Zermeño, Krzysztof Habelok, Mariusz Stępień, Francesco Grilli

摘要:

高温超导体器件的临界电流($I_c$)和交流损耗的计算需要超导材料的临界电流密度($J_c$)。该$J_c$通常不是恒定的,并且取决于局部磁通量密度的大小($B_{loc}$)和方向($θ$,相对于磁带)。原则上,$J_c(B_{loc},θ)$可以从实验测量的临界电流$I_c(B_a,θ)$获得,其中$B_a$是所施加磁场的大小。然而,对于其中超导材料经历接近于隔离导体的自场的局部场的应用,从$I_c(B_a,θ)$获得$J_c(B_{loc},θ)$不是简单的任务。这是必要的,以解决一个反问题,以纠正来自自场的贡献。文献中提出的方法包括一系列处理不同程度的数学正则化的方法,例如使用蛮力或优化方法来拟合预想的非线性公式的参数。在这方面的贡献,我们提出了一个无参数的方法,提供了很好的再现实验数据,不需要人为的互动或先入为主的$J_c$依赖于磁场。特别是,它允许在几分钟内从实验数据到准备运行的$J_c(B_{loc},θ)$模型。

英文摘要:

The estimation of the critical current ($I_c$) and AC losses of high-temperature superconductor (HTS) devices through modeling and simulation requires the knowledge of the critical current density ($J_c$) of the superconducting material. This $J_c$ is in general not constant and depends both on the magnitude ($B_{loc}$) and the direction ($θ$, relative to the tape) of the local magnetic flux density. In principle, $J_c(B_{loc},θ)$ can be obtained from the experimentally measured critical current $I_c(B_a,θ)$, where $B_a$ is the magnitude of the applied magnetic field. However, for applications where the superconducting materials experience a local field that is close to the self field of an isolated conductor, obtaining $J_c(B_{loc},θ)$ form $I_c(B_a,θ)$ is not a trivial task. It is necessary to solve an inverse problem to correct for the contribution derived from the self field. The methods presented in the literature comprise a series of approaches dealing with different degrees of mathematical regularization, such as the use of brute force or optimization methods to fit the parameters of preconceived non linear formulas. In this contribution, we present a parameter-free method that provides excellent reproduction of experimental data and requires no human interaction or preconception of the $J_c$ dependence with respect to the magnetic field. In particular, it allows going from the experimental data to a ready-to-run $J_c(B_{loc},θ)$ model in a few minutes.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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