Generalised magnetic polarizability tensors
Generalised magnetic polarizability tensors
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DOI：
10.1002/mma.4809
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发表时间：
2017-05
影响因子：
2.9
通讯作者：
P. Ledger;W. Lionheart
中科院分区：
文献类型：
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作者：
P. Ledger;W. Lionheart
对于麦克斯韦方程的涡流区，我们提出了一种新的完全渐近展开式，用于描述导电(可渗透)物体的尺寸趋于零时，由于导体(可渗透)物体的存在而引起的低频时谐磁场扰动。新的渐近展开式允许用一类新的广义磁极化率张量来表征这类物体的形状和材料性质，我们给出了它们的计算的显式公式。我们的结果将对金属探测器具有重要的意义，因为它将改善对小对象的识别，并且对于背景场随包裹体变化的情况，该信息将在识别它们的形状和材料属性方面是有用的，甚至是有用的。因此，提高金属探测器定位地雷和未爆弹药、在回收过程中对金属进行分类、确保食品安全以及加强机场和公共活动的安全检查的能力。
We present a new complete asymptotic expansion for the low‐frequency time‐harmonic magnetic field perturbation caused by the presence of a conducting (permeable) object as its size tends to zero for the eddy current regime of Maxwell's equations. The new asymptotic expansion allows the characterisation of the shape and material properties of such objects by a new class of generalised magnetic polarizability tensors, and we provide an explicit formula for their calculation. Our result will have important implications for metal detectors since it will improve small object discrimination, and for situations where the background field varies over the inclusion, this information will be useable, and indeed useful, in identifying their shape and material properties. Thus, improving the ability of metal detectors to locate landmines and unexploded ordnance, sort metals in recycling processes, and ensure food safety as well as enhancing security screening at airports and public events.