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Generalised magnetic polarizability tensors
Mathematical Methods in the Applied Sciences, Volume: 41, Issue: 8, Pages: 3175 - 3196
Swansea University Author: Paul Ledger
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DOI (Published version): 10.1002/mma.4809
Abstract
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 characte...
| Published in: | Mathematical Methods in the Applied Sciences |
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| ISSN: | 0170-4214 |
| Published: |
2018
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| Online Access: |
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| URI: | https://cronfa.swan.ac.uk/Record/cronfa38104 |
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| Abstract: |
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. |
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| Keywords: |
asymptotic expansion, eddy currents, landmine detection, metal detectors, polarizability tensors |
| College: |
Faculty of Science and Engineering |
| Issue: |
8 |
| Start Page: |
3175 |
| End Page: |
3196 |