Modeling and analysis of three-dimensional quasi-stationary electromagnetic fields of non-contact inductometers placed above the conductive agricultural soil. Part ІІ.

Abstract

The paper is devoted to solving the problem of the theory of three-dimensional quasi-stationary electromagnetic field generated by a non-contact inductometer in its interaction with the electrically conductive agricultural soil located below it at some distance and whose specific electrical conductivity is measured. The peculiarity of this study is that it is based on obtaining an accurate analytical solution to the problem of an electromagnetic field created by an arbitrary spatial circuit with a current (contactless inductometer model) located near a magnetized electrically conductive body with a flat surface (agricultural conductive soil model). Solutions made by taking into account the closed circuits are found in the form of squares for vector and scalar potentials, magnetic and electric field strengths in an electrically conductive medium without restrictions on the geometry of the circuits, environmental properties, and field frequency. Having a precise solution, in addition to the indisputable advantage associated with the validity of the results found, allows obtaining a number of consequences that are valid for an arbitrary field in the system. Another important consequence of an accurate solution is the conclusion that an inhomogeneous electromagnetic field when penetrating into an electrically conductive space with depth always attenuates faster than a homogeneous field. For pulsed fields, the calculation is limited to a certain period of time from the beginning of the current pulse, and the closer to the initial moment of time, the more accurately the electromagnetic field is calculated. Since the current pulse usually changes the fastest and reaches its highest values in a relatively short period of time, it is at this most important stage that the electromagnetic field is determined.