Approximated Solutions for ELF Near-Field Propagation Due to a Horizontal Electric Dipole Excitation Near the Sea-Rock Boundary

Xu, Haitan; Gu, Ting Ting; Li, Kai

doi:10.1109/tap.2018.2810328

Cited by 18 publications

(7 citation statements)

References 17 publications

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“…However, due to the existence of discrete singular points in the complex plane, VOLUME XX, 2017 obtaining a highly precise numerical solution becomes cumbersome. In the following decades, scholars simplified the Sommerfeld integral method to varying degrees to obtain the propagation characteristics of EMWs in different media [5][6][7][8][9], but the process of solving it mathematically is highly complex., which makes it very difficult to apply in studies on ocean exploration.…”

Section: Introductionmentioning

confidence: 99%

Propagation Characteristics of Extremely Low-Frequency Electromagnetic Waves in a Uniformly Infinite Polar “Sea-Sea Ice” Half-Space

Hu,

Xie,

Feng

2023

IEEE Access

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In this study, we accurately calculated the propagation characteristics of extremely lowfrequency (ELF) electromagnetic waves (EMWs) excited by horizontal electric dipoles (HEDs) in the uniformly infinite polar "sea-sea ice" half-space. This was achieved by combining the program platform written by the message passing interface (MPI) with the three-dimensional total field scattered field source finite difference time domain (TSS-FDTD) method to develop an improved calculation method of parallel TSS-FDTD electromagnetic field. Using equivalent principle and boundary grid field value transformation technology, the calculation space of electromagnetic field (EMF) in seawater and sea ice is divided into several regional grids to establish the calculation model of TSS-FDTD in the polar "sea-sea ice" half-space. The maximum radiation direction and average minimum attenuation of ELF EMF in the uniformly infinite polar "sea-sea ice" half-space (near the interface between seawater and sea ice) are obtained. The simulation results show that, at depth d=10 m and propagation distance ρ=125 m from the interface between seawater and sea ice, the maximum radiation directions of EMF intensity are vertical electric field direction Ez and horizontal magnetic field direction Hx, respectively; moreover, their average minimum attenuation values in the sea water medium are 30 dB and 20 dB, respectively, and their corresponding values in sea ice medium are 20 dB and 10 dB, respectively. Therefore, compared with the directions of other electric and magnetic field components, these directions more suitable for receiving underwater signals. Finally, we selected different thickness values of the sea ice medium for simulation, and compared the results with the Sommerfeld numerical integration method (SNIM) proposed by Pan. The results show that the calculation results of the two methods are consistent, and that the average error is less than 5%, which verifies the effectiveness and accuracy of the proposed method.INDEX TERMS Extremely low-frequency (ELF)；Electromagnetic waves; Horizontal electric dipole (HED); Sea; Finite difference time domain (FDTD).

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Section: Introductionmentioning

confidence: 99%

Propagation Characteristics of Extremely Low-Frequency Electromagnetic Waves in a Uniformly Infinite Polar “Sea-Sea Ice” Half-Space

Hu,

Xie,

Feng

2023

IEEE Access

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“…The solutions are obtained by extending some earlier work of by first applying the boundary conditions to determine the electric and magnetic Hertz potentials in the form of Sommerfeld integrals (SIs), respectively, and then relating these to auxiliary integrals, their derivatives, and asymptotic series 23 . The SIs representing the electromagnetic wave propagation due to a vertical electric dipole, which has been established for over a century, is essential for the understanding of EM radiation scheme of the natural ELF noises due to lightning discharges 24 …”

Section: Introductionmentioning

confidence: 99%

The mode‐conversion coefficient of ELF wave propagation due to land‐to‐sea transition

Xu¹,

Zhu³

et al. 2020

Int J Numerical Modelling

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The mode‐conversion coefficient is studied to investigate the ELF wave propagation over a mixed land‐to‐sea path. As partition by the consideration of reflection influence from the ionosphere layer, we assume the propagation can be regarded as being subjected to two different models over mixed paths, in terms of the propagation distance in the range of ELF far‐field and near‐field regions, respectively. Both of the mentioned stratified models can be represented as cascaded transmission networks at the abrupt junctions. In conformity with previous study to formulate the far‐field propagation as a cascaded terrestrial waveguide with abrupt height and ground impedance changes, the presented study proposed an equivalent cascaded network to exploit the concept of mode‐conversion for near‐field propagation across discontinuity. Representative parameters of ground types in contrast are supportive to demonstrate the interference of abrupt impedance‐change at ELF band. The presented analysis provide with computational schemes to obtain synthetic fields of ELF wave propagation, which could be extended to more realistic model over multi‐segmental mixed paths.

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“…Due to the divergence terms in Sommerfeld integrals, the investigation of ELF/SLF near-zone field is still not well developed yet. In the recent work by Xu et al [16], a new quasi-static technique is used for analyzing the near-zone field radiated by a horizontal electric dipole near the sea-rock boundary.…”

Section: Introductionmentioning

confidence: 99%

“…However, the corresponding study on this near-field radiation of a vertical magnetic dipole is still in the dark. Since it is a formidable task to calculate it accurately by existing analytical methods, in this paper, we will attempt to extend the work by Xu et al [16] and evaluate the integrals in purpose of deriving new approximation formulas.…”

Section: Introductionmentioning

confidence: 99%

Quasi-Static Solution for ELF/SLF near-Zone Field of a Vertical Magnetic Dipole near the Surface of a Lossy Half-Space

2020

International Journal of Antennas and Propagation

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Dipole antennas over the boundary between two different media have been widely used in the fields of geophysics exploration, oceanography, and submerged communication. In this paper, an analytical method is proposed to analyse the near-zone field at the extremely low frequency (ELF)/super low frequency (SLF) range due to a vertical magnetic dipole (VMD). For the lack of feasible analytical techniques to derive the components exactly, two reasonable assumptions are introduced depending on the quasi-static definition and the equivalent infinitesimal theory. Final expressions of the electromagnetic field components are in terms of exponential functions. By comparisons with direct numerical solutions and exact results in a special case, the correctness and effectiveness of the proposed quasi-static approximation are demonstrated. Simulations show that the smallest validity limit always occurs for component H2z, and the value of k2ρ should be no greater than 0.6 in order to keep a good consistency.

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Approximated Solutions for ELF Near-Field Propagation Due to a Horizontal Electric Dipole Excitation Near the Sea-Rock Boundary

Cited by 18 publications

References 17 publications

Propagation Characteristics of Extremely Low-Frequency Electromagnetic Waves in a Uniformly Infinite Polar “Sea-Sea Ice” Half-Space

Propagation Characteristics of Extremely Low-Frequency Electromagnetic Waves in a Uniformly Infinite Polar “Sea-Sea Ice” Half-Space

The mode‐conversion coefficient of ELF wave propagation due to land‐to‐sea transition

Quasi-Static Solution for ELF/SLF near-Zone Field of a Vertical Magnetic Dipole near the Surface of a Lossy Half-Space

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