Numerical Scheme for Modelling the Electromagnetic Field in Airborne Electromagnetic Survey Taking into Account Follow Currents in Transmitter Loop

• Main Authors: Persova, Marina G., Soloveichik, Yuri G., Vagin, Denis V., Koshkina, Yulia I., Simon, Evgenia I.
• Format: Conference Proceeding
• Language: English
• Subjects: 3-D modeling; airborne electromagnetic survey; Current measurement; Electromagnetic field; Electromagnetic fields; follow currents; Geologic measurements; Geophysical measurements; Receivers; Transmitters
• ISSN: 2473-8573
• DOI: 10.1109/APEIE.2018.8546324

The paper proposes a numerical scheme which makes it possible to calculate the electromagnetic signals in airborne electrical survey problems for the complex form of the current impulse and follow currents in the transmitter loop. In order to calculate the electromagnetic field, the finite element method is used. For taking into account the time-depending current, the "convolution" procedure, which is based on the piecewise constant approximation of the current function and field calculation for the current in the form of the Heaviside function, is used. The problem related to the error of this approximation, in the case when the transmitter loop is located at some altitude above the Earth surface, is discussed. The results of verifying the proposed computational scheme, comparative analysis of computational costs and analysis of the follow current effect are presented. The results of the numerical experiments show that, on the one hand, when the modeling of the airborne electromagnetic signals is performed, it is necessary to take into account the current form (including the follow current), but, on the other hand, this can be performed most accurately and with low costs by the approach proposed in this paper.