Modeling of Thin Shielding Layer Based on Unstructured Grid Vector Finite Element Method and Analysis of its Effect on SQUID TEM Observation Signal

Authors

  • Binyuan Ma College of Instrumentation and Electrical Engineering Jilin University, Changchun 130000, China
  • Nansong Chang College of Instrumentation and Electrical Engineering Jilin University, Changchun 130000, China
  • Yanju Ji College of Instrumentation and Electrical Engineering Jilin University, Changchun 130000, China, Key Laboratory of Geophysical Exploration Equipment Ministry of Education Jilin University, Changchun 130000, China
  • Xuejiao Zhao College of Instrumentation and Electrical Engineering Jilin University, Changchun 130000, China, Key Laboratory of Geophysical Exploration Equipment Ministry of Education Jilin University, Changchun 130000, China
  • Hui Luan College of Instrumentation and Electrical Engineering Jilin University, Changchun 130000, China, Key Laboratory of Geophysical Exploration Equipment Ministry of Education Jilin University, Changchun 130000, China

DOI:

https://doi.org/10.13052/2026.ACES.J.410304

Keywords:

SQUID TEM, Thin shielding layer modeling, Unstructured tetrahedral mesh, Vector Finite Element Method

Abstract

Superconducting Quantum Interference Devices Time-Domain Electromagnetic Method (SQUID TEM) is currently the most accurate electromagnetic detection technology used in geophysics. However, SQUID is highly susceptible to electromagnetic interference in outdoor spaces, so it needs to work continuously and stably in a Dewar bucket wrapped with a metal shielding material. Therefore, the influence of the metal shielding thin layer on the observation signal cannot be ignored. We propose a vector finite element method based on unstructured grids to spatially model the sleeve formed by the metal shielding thin layer wrapped around the SQUID and analyze the influence of the metal shielding sleeve on the SQUID TEM observation signal. Firstly, we derive the governing equations from Maxwell’s equations. Secondly, the Galerkin method is used for finite element discretization of the control equations, and unstructured mesh discretization is applied to the metal shielding sleeve and other computational areas. By solving the interpolation basis functions of tetrahedral vector elements, the local equations of each element are obtained and combined into a global large sparse matrix. Finally, the direct solution method is used to calculate the electromagnetic response at the observation points inside the metal shielding sleeve. The effectiveness and universality of the proposed method are verified through numerical simulations. Furthermore, through field experiments in the Da Hinggan Ling area, the necessity of metal shielding sleeves in field experiments and the reliability of the calculation results proposed have been demonstrated.

Downloads

Download data is not yet available.

Author Biographies

Binyuan Ma, College of Instrumentation and Electrical Engineering Jilin University, Changchun 130000, China

Binyuan Ma received the B.S. degree in measurement and control technology and instrumentation from the College of Instrumentation and Electrical Engineering, Jilin University, Changchun, China, in 2018, where he is currently pursuing the Ph.D. degree in detection technology and automatic equipment. His research interests include artificial intelligence algorithms, electromagnetic signal correction & processing, parameters extraction and their applications in SQUID TEM detection.

Nansong Chang, College of Instrumentation and Electrical Engineering Jilin University, Changchun 130000, China

Nansong Chang received the B.S. degree in electrical engineering and automation from the College of Instrumentation and Electrical Engineering, Jilin University, Changchun, China, in 2020, where she is currently pursuing the Ph.D. degree in detection technology and automatic equipment. Her research interests include electromagnetic signal data processing and parameter extraction, deep learning algorithms and applications of electromagnetic signals in superconductivity.

Yanju Ji, College of Instrumentation and Electrical Engineering Jilin University, Changchun 130000, China, Key Laboratory of Geophysical Exploration Equipment Ministry of Education Jilin University, Changchun 130000, China

Yanju Ji received the M.S. degree in measurement technology and instrument and the Ph.D. degree in Earth exploration and information techniques from Jilin University, Changchun, China, in 1998 and 2004, respectively. From 2004 to 2009, she was an Associate Professor with Jilin University. Since 2010, she has been with Jilin University where she is currently a Professor of instrument science and technology. She has authored or coauthored more than 200 articles. Her current research interests include computational electromagnetics, inverse problems, and electromagnetic detecting instrument.

Xuejiao Zhao, College of Instrumentation and Electrical Engineering Jilin University, Changchun 130000, China, Key Laboratory of Geophysical Exploration Equipment Ministry of Education Jilin University, Changchun 130000, China

Xuejiao Zhao received the B.S. degree in electrical engineering and automation, and the Ph.D. degree in detection technology and automatic equipment from Jilin University, Changchun, China, in 2013 and 2019, respectively. She is currently a Post-Doctoral Fellow in instrument science and technology with Jilin University. She has authored or coauthored more than 20 papers in journals and conference proceedings. Her research interests include electromagnetic anomalous diffusion and time-space fractional differential solution in the time domain.

Hui Luan, College of Instrumentation and Electrical Engineering Jilin University, Changchun 130000, China, Key Laboratory of Geophysical Exploration Equipment Ministry of Education Jilin University, Changchun 130000, China

Hui Luan received the Ph.D. degree in microwave remote sensing from the Chinese Academy of Science, Beijing, China, in 2007. Since 2007, she has been with the College of Instrumentation and Electrical Engineering, Jilin University, Changchun, where she is currently a Professor. Her research interests include the development of transient electromagnetic instruments and electromagnetic numerical simulation.

References

R. Stolz, M. Schiffler, M. Becken, A. Thiede, M. Schneider, G. Chubak, P. Marsden, A. B. Bergshjorth, M. Schaefer, and O. Terblanche, “SQUIDs for magnetic and electromagnetic methods in mineral exploration,” Mineral Economics, vol. 35, pp. 467–494, 2022.

R. Stolz, M. Schmelz, V. Zakosarenko, C. Foley, K. Tanabe, X. Xie, and R. L. Fagaly, “Superconducting sensors and methods in geophysical applications,” Superconductor Science and Technology, vol. 34, pp. 1–33, 2021.

E. Arai, “State-of-the-art geophysics for metal exploration,” Resource Geology, vol. 71, pp. 470–491, 2021.

H. Ren, Y. Wang, C. Chen, G. Fu, L. Qiu, L. Guo, C. Xie, Y. He, H. Sun, and J. Teng, “Underground laboratories ⋅ Deep underground observation ⋅ Scientific questions—Insights from observations of multi-physic fields in deep underground labs,” Science China Earth Sciences, vol. 68, pp. 343–362, 2025.

J. Wu, Q. Zhi, X. Deng, X. Wang, X. Chen, Y. Zhao, and Y. Huang, “Deep gold exploration with SQUID TEM in the Qingchengzi Orefield, Eastern Liaoning, Northeast China,” Minerals, vol. 12, p. 102, 2022.

I. Mohanty, R. Nagendran, L. Bisht, A. V. T. Arasu, R. Baskaran, B. V. L. Kumar, and M. B. Verma, “Development of SQUID based TDEM system and its utilization for field survey at Tumallapalle, Andhra Pradesh, India,” Journal of Applied Geophysics, vol. 204, p. 104746, 2022.

A. Revil, D. Mao, Z. Shao, M. F. Sleevi, and D. Wang, “Induced polarization response of porous media with metallic particles—Part 6: The case of metals and semimetals,” Geophysics, vol. 82, pp. E97–E110, 2017.

D. J. Marshall and T. R. Madden, “Induced polarization, a study of its causes,” Geophysics, vol. 24, pp. 790–816, 1959.

G. Xue, N. Zhou, B. Su, A. Zhang, Y. Yang, J. Mo, and X. Wu, “Geophysical exploration strategy for Cu-Ni-Co deposits in China: A review,” Geophysics, vol. 89, pp. WB25–WB34, 2024.

Z. Guo, G. Xue, J. Liu, and X. Wu, “Electromagnetic methods for mineral exploration in China: A review,” Ore Geology Reviews, vol. 118, p. 103357, 2020.

S. Du, Y. Zhang, Y. Pei, K. Jiang, L. Rong, C. Yin, Y. Ji, and X. Xie, “Study of transient electromagnetic method measurements using a superconducting quantum interference device as B sensor receiver in polarizable survey area,” Geophysics, vol. 83, pp. E111–E116, 2018.

B. Ma, Y. Ji, Y. Ma, Q. Wu, X. Zhao, D. Li, M. Teng, and Y. Yu, “Research on parameters extraction of resistivity and polarizability from SQUID TEM data based on adaptive differential optimization algorithm,” Chinese Journal of Geophysics, vol. 67, pp. 4468–4481, 2024.

J. R. Claycomb and J. H. Miller, “Superconducting magnetic shields for SQUID applications,” Review of Scientific Instruments, vol. 70, pp. 4562–4568, 1999.

R. L. Fagaly, “Superconducting quantum interference device instruments and applications,” Review of Scientific Instruments, vol. 77, pp. 1–45, 2006.

L. Wei, G. Wang, J. Li, S. Zhang, and G. Hong, “Multilayer magnetic shielding for testing a superconducting single-flux-quantum circuit chip in liquid helium Dewar,” Journal of Instrumentation, vol. 16, p. 04007, 2021.

H. He, T. Li, and R. Zhang, “Joint inversion of 3D gravity and magnetic data under undulating terrain based on combined hexahedral grid,” Remote Sensing, vol. 14, pp. 4651–4673, 2022.

X. Cao, X. Huang, C. Yin, L. Yan, and Y. Han, “3-D inversion of Z-axis tipper electromagnetic data using finite-element method with unstructured tetrahedral grids,” IEEE Transactions on Geoscience and Remote Sensing, vol. 60, pp. 1–11, 2021.

J. Zhu, C. Yin, L. Gao, Z. Hui, Y. Liu, X. Ren, B. Zhang, J. Wang, and B. Xiong, “3D unstructured spectral element method for frequency-domain airborne EM forward modeling based on Coulomb gauge,” IEEE Transactions on Geoscience and Remote Sensing, vol. 60, pp. 1–13, 2022.

K. Key, “MARE2DEM: A 2-D inversion code for controlled-source electromagnetic and magnetotelluric data,” Geophysical Journal International, vol. 207, pp. 571–588, 2016.

J. Li, Y. Li, Y. Liu, K. Spitzer, and B. Han, “3-D marine CSEM forward modeling with general anisotropy using an adaptive finite-element method,” IEEE Geoscience and Remote Sensing Letters, vol. 18, pp. 1936–1940, 2021.

Y. Zhou, Y. Yi, J. Li, and X. Hu, “Response characteristics of transient electromagnetic methods for unexploded ordnances considering metal shell thickness and shell fragments,” IEEE Transactions on Geoscience and Remote Sensing, vol. 62, pp. 1–13, 2020.

Z. Rong, Y. Liu, C. Yin, L. Wang, X. Ma, C. Qiu, B. Zhang, X. Ren, Y. Su, and A. Weng, “Threedimensional magnetotelluric inversion for arbitrarily anisotropic earth using unstructured tetrahedral discretization,” Journal of Geophysical Research: Solid Earth, vol. 127, pp. 1–26, 2022.

Y. Liu, S. Liu, M. Li, X. Liu, and W. Guo, “Influence of metal roadway supports on transient electromagnetic detection in mines,” Earth Sciences Research Journal, vol. 25, pp. 109–114, 2021.

L. Zhou and Y. Gao, “Mechanical-electromagnetic coupling enriched finite element method for static analysis of magneto-electroelastic composites,” Mechanics of Advanced Materials and Structures, vol. 31, pp. 4374–4386, 2024.

K. Etse, P. Clerico, L. Prevond, A. L. Helbert, T. Baudin, and X. Mininger, “Comparative study of thin layers modeling in electromagnetism: Application to multilayer magnetic shielding,” IEEE Transactions on Electromagnetic Compatibility, vol. 65, pp. 1351–1359, 2023.

Y. Gao, D. Ma, K. Wang, X. Xu, S. Li, Y. Dou, and J. Li, “A low-noise multilayer Mu-metal thin shell magnetic shield for ultra-highly sensitive atomic sensors,” Sensors and Actuators A: Physical, vol. 352, p. 114207, 2023.

G. Korkotadze, G. Chiqovani, and R. Jobava, “Analytical prediction of magnetic field shielding for multilayer thin sheets excited by loop sources,” in 2024 IEEE 29th International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory (DIPED), Tbilisi, Georgia, pp. 12–17, 2024.

Y. Yang, F. Zhu, N. Lu, and Y. Xiao, “Study on the electromagnetic interference of shielded cable in rail weighbridge,” Applied Computational Electromagnetics Society (ACES) Journal, vol. 37, pp. 215–221, 2022.

M. I. Mousa, Z. Abdul-Malek, and M. R. M. Esa, “Effects of return stroke parameters and soil water content on EMF characteristics,” Applied Computational Electromagnetics Society (ACES) Journal, vol. 34, pp. 1219–1225, 2019.

M. N. S. Kumar, R. Murugan, J. Lydia, and S. L. S. Vimalraj, “Investigations on the influence of augmented rail geometry on rail gun design parameters using finite element method,” Applied Computational Electromagnetics Society (ACES) Journal, vol. 40, pp. 564–570, 2025.

X. Zhang, R. Chen, and A. Zhan, “A difference subgridding method for solving multiscale electro-thermal problems,” Applied Computational Electromagnetics Society (ACES) Journal, vol. 37, pp. 168–175, 2022.

M. Xue and J. Jin, “Finite-element domain decomposition methods for analysis of large-scale electromagnetic problems,” Applied Computational Electromagnetics Society (ACES) Journal, vol. 29, pp. 990–1002, 2014.

S. Zuo, Y. Zhang, D. G. Doñoro, X. Zhao, and Q. Liu, “A novel finite element mesh truncation technology accelerated by parallel multilevel fast multipole algorithm and its applications,” Applied Computational Electromagnetics Society (ACES) Journal, vol. 34, pp. 1671–1678, 2019.

S. Zuo, Z. Lin, Z. Yue, D. G. Doñoro, Y. Zhang, and X. Zhao, “An efficient parallel hybrid method of FEM-MLFMA for electromagnetic radiation and scattering analysis of separated objects,” Applied Computational Electromagnetics Society (ACES) Journal, vol. 35, pp. 1127–1136, 2020.

J. M. Jin, The Finite Element Method in Electromagnetics. Hoboken, NJ: John Wiley & Sons, 2015.

J. H. Knight and A. P. Raiche, “Transient electromagnetic calculations using the GaverStehfest inverse Laplace transform method,” Geophysics, vol. 47, pp. 47–50, 1982.

M. Bick, G. Panaitov, N. Wolters, Y. Zhang, H. Bousack, A. I. Braginski, U. Kalberkamp, H. Burkhardt, and U. Matzander, “A HTS rf SQUID vector magnetometer for geophysical exploration,” IEEE Transactions on Applied Superconductivity, vol. 9, pp. 3780–3785, 1999.

T. Nagaishi, H. Ota, E. Arai, T. Hayashi, and H. Itozaki, “High Tc SQUID system for transient electromagnetic geophysical exploration,” IEEE Transactions on Applied Superconductivity, vol. 15, pp. 749–752, 2005.

A. Chwala, R. Stolz, M. Schmelz, V. Zakosarenko, M. Meyer, and H. G. Meyer, “SQUID systems for geophysical time domain electromagnetics (TEM) at IPHT Jena,” IEICE Transactions on Electronics, vol. 98, pp. 167–173, 2015.

Downloads

Published

2026-03-30

How to Cite

[1]
B. . Ma, N. . Chang, Y. . Ji, X. . Zhao, and H. . Luan, “Modeling of Thin Shielding Layer Based on Unstructured Grid Vector Finite Element Method and Analysis of its Effect on SQUID TEM Observation Signal”, ACES Journal, vol. 41, no. 03, pp. 225–237, Mar. 2026.

Issue

2026: Vol 41 Iss 3

Section

General Submission

Categories