发表机构
School of Engineering, Institute of Science Tokyo; Research and Innovation Center, Mitsubishi Heavy Industries, Ltd.（东京科学大学工学院; 三菱重工业有限公司研究与创新中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究提出利用电流偶极子模型检测微尺度金属缺陷，通过磁场测量重建偶极子位置和强度，实现缺陷定位与体积评估，并验证了在铜及磁性材料中的适用性。
AI 中文摘要
有效电流偶极子为局部电流扰动提供了一种紧凑的描述，并已被广泛应用于各种物理系统和长度尺度。尽管其在宏观系统中得到广泛使用，但其在微尺度材料诊断中的适用性仍未得到探索。在本研究中，我们证明了电流偶极子表示为导电材料中微观缺陷的检测和表征提供了一个有效的物理框架。当外部电流施加到金属上时，缺陷会局部扰动电流分布，从而产生一个有效的面内电流偶极子，该偶极子产生特征性的磁场图案。通过测量金属上方的磁场分布并将其与偶极子模型拟合，我们重建了偶极子的位置和有效强度，从而能够推断缺陷位置和有效缺陷体积度量。使用宽场磁成像作为测量平台，我们观察到了来自铜样品前表面一个38微米长缺陷的与缺陷相关的磁信号，并使用0.5毫米厚的铜板识别了后表面的缺陷。我们进一步检验了该方法对磁性材料的适用性，其中磁导率对比会改变场分布。我们的结果确立了电流偶极子成像作为缺陷磁检测的通用物理框架，并突显了其在不同长度尺度上进行无损检测的潜力。
英文摘要
An effective electric current dipole provides a compact description of localized current disturbances and has been employed across a broad range of physical systems and length scales. Despite its extensive use in macroscopic systems, its applicability to microscale material diagnostics remains unexplored. In this study, we demonstrate that the current-dipole representation provides an effective physical framework for the detection and characterization of microscopic defects in conductive materials. When an external current is applied to a metal, defects locally perturb the current distribution, thus generating an effective in-plane current dipole that yields a characteristic magnetic-field pattern. By measuring the magnetic-field distribution above the metal and fitting it with a dipole model, we reconstruct the position and effective strength of the dipole, thereby enabling the inference of the defect location and an effective defect-volume metric. Using wide-field magnetic imaging as a measurement platform, we observe a defect-associated magnetic signal from a 38-um-long defect on the front surface of copper samples and identify a defect on the back surface using a 0.5-mm-thick copper plate. We further examine the applicability of this approach to magnetic materials, where permeability contrasts modify the field distribution. Our results establish current-dipole imaging as a general physical framework for magnetic detection of defects and highlight its potential for nondestructive inspection across a wide range of length scales.
Comments13 pages, 5 figures
