Effect of Ionosphere and Inhomogeneity of the Earth Structure on the Polarization Characteristics of Magnetic Field at Frequencies of 0.2–200 Hz in the Near-Field Zone of a Horizontal Grounded Antenna

2019 ◽  
Vol 64 (7) ◽  
pp. 1029-1035 ◽  
Author(s):  
E. D. Tereshchenko ◽  
A. E. Sidorenko ◽  
P. E. Tereshchenko
Keyword(s):  
Magnetic Field ◽  
Near Field ◽  
Earth Structure ◽  
Field Zone ◽  
The Earth ◽  
Polarization Characteristics

scholarly journals Влияние ионосферы и неоднородной структуры Земли на поляризационные характеристики магнитного поля в диапазоне частот 0.2-200 Hz в ближней зоне горизонтальной заземленной антенны

2019 ◽  
Vol 89 (7) ◽  
pp. 1092
Author(s):  
Е.Д. Терещенко ◽  
А.Е. Сидоренко ◽  
П.Е. Терещенко
Keyword(s):  
Near Field ◽  
Low Frequency ◽  
Major Axis ◽  
Earth Structure ◽  
Field Zone ◽  
K Index ◽  
The Earth ◽  
Polarization Characteristics ◽  
Deep Sounding ◽  
Theoretical Results

AbstractPolarization characteristics of the field of an on-Earth emitter located at the Kola Peninsula are experimentally measured at a distance that is no greater than the height of an effective ionospheric waveguide in the FENICS-2014 experiment. Variations in the field amplitude and orientation of the major axis of polarization ellipse are observed at lower frequencies upon significant changes of the K index of geomagnetic activity. Polarization characteristics of the horizontal component of magnetic field calculated with allowance for the ionosphere and two-layer Earth structure prove the observed sensitivity of the ultralow- and lower-frequency filed in the near-field zone to the state of ionosphere at lower conductivity of underlying medium. Theoretical results are compared with the experimental data. The results are important for deep sounding of the Earth and monitoring of ionosphere with the aid of controlled low-frequency ground sources.

scholarly journals Roald Amundsen's Arctic research role in the development of Geophysics: the case of the 1903-1906 expedition

2020 ◽  
Vol 84 ◽  
pp. 01001
Author(s):  
Valeriy Kramskiy ◽  
Ekaterina Samylovskaya ◽  
Stefano Maria Capilupi
Keyword(s):  
Magnetic Field ◽  
Arctic Region ◽  
The Arctic ◽  
Earth Structure ◽  
Northwest Passage ◽  
The Earth ◽  
Magnetic Poles ◽  
Further Development ◽  
The Magnetic Field ◽  
The Arctic Region

The paper discusses Roald Amundsen’s discoveries in the sphere of knowledge about the Earth’s magnetic field, made during the Arctic expedition of 1903-1906. A historical overview of previous discoveries made by scientists in the process of studying Geomagnetism is given. The research is based on the study and analysis of R. Amundsen’s memoirs about the expedition. The authors consistently consider the stages of the expedition along the Northwest passage in 1903-1906 and its results. The significance of the geomagnetic characteristics obtained in this expedition is shown. Attention is paid to the phenomenon of magnetic poles drift, and the process of its discovery is described in detail. Amundsen’s discovery of magnetic drift gave an invaluable impetus for further Geomagnetism development, which is also briefly considered. Observations made by Roald Amundsen helped to take a new look at the existing scientific picture of the world, to challenge the traditional model of the Earth structure and to construct a new and, in many ways, revolutionary scheme. As a result of the research, the authors of the paper come to the conclusion that the expedition of 1903-1906 is one of the greatest scientific breakthroughs of that time, also in the sphere of Geophysics. Scientists processed the recorded characteristics of the magnetic field in the Arctic until the 30s of the 20th century. This huge flow of data allowed to supplement the existing maps with magnetic declination and inclination readings in the studied area, and thus to simplify further development of the Arctic region.

scholarly journals Localization of Alternating Magnetic Dipole in the Near-Field Zone with Single-Component Magnetometers

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Gao Xiang ◽  
Du Bo-cheng ◽  
Wang Qi-long
Keyword(s):  
Magnetic Field ◽  
Magnetic Dipole ◽  
Near Field ◽  
Vertical Component ◽  
Low Frequency ◽  
Single Component ◽  
Dipole Source ◽  
Magnetic Field Measurement ◽  
Field Zone ◽  
Theoretical Simulation

Tri-axis magnetometers are widely used to measure magnetic field in engineering of the magnetic localization technology. However, the magnetic field measurement precision is influenced by the nonorthogonal error of tri-axis magnetometers. A locating model of the alternating magnetic dipole in the near-field zone with single-component magnetometers was proposed in this paper. Using the vertical component of the low-frequency magnetic field acquired by at least six single-component magnetometers, the localization of an alternating magnetic dipole could be attributed to the solution for a class of nonlinear unconstrained optimization problem. In order to calculate the locating information of alternating magnetic dipole, a hybrid algorithm combining the Gauss–Newton algorithm and genetic algorithm was applied. The theoretical simulation and field experiment for the localization of alternating magnetic dipole source were carried out, respectively. The positioning result is stable and reliable, indicating that the locating model has better performance and could meet the requirements of actual positioning.

The effects of 3D topography on controlled-source audio-frequency magnetotelluric responses

Geophysics ◽  
2018 ◽  
Vol 83 (2) ◽  
pp. WB97-WB108 ◽  
Author(s):  
Changhong Lin ◽  
Sumei Zhong ◽  
Esben Auken ◽  
Hongzhu Cai ◽  
Handong Tan ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Apparent Resistivity ◽  
Near Field ◽  
Topographic Effects ◽  
Field Zone ◽  
3D Topography ◽  
Phase Data ◽  
The Hill ◽  
The Magnetic Field

We have investigated the 3D topographic effects on controlled-source audio-frequency magnetotelluric data. Two 3D topographic models are considered: a trapezoidal-hill model and a trapezoidal-valley model. Different responses are generated, including the amplitude of the electric field, the amplitude of the magnetic field, the apparent resistivity, and phase data. The responses distorted by the 3D topography are simulated for the source located next to and on the hill/valley. Our study indicates that all electric field, magnetic field, apparent resistivity, and phase data are influenced by 3D topography, but to different extents. These topographic effects depend on the transmission-receiver-topography geometry, the transmission frequency, earth resistivity, and the roughness of the surface. The effects in the near-field generated by topography in the survey area are quite different from those in the far-field because of the existence of the source. Compared with those in the far-field zone, the magnetic field and phase data in the near-field zone are less distorted, but more distortions can be found on the electric field and apparent resistivity data over the hill and valley models. Our results also indicate that not only can the 3D topography in the receiver area lead to strong distortions, but also that at the source position can lead to strong distortions. We concluded our study by quantifying the roughness with which the topographic distortion can be ignored, setting the accepted data distortion to a maximum of 10%.

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