Geophysical Journal | 2004 volume 26 1

Fundamental models of electromagnetic sounding systems

© Shuman V.N.

Physical mechanisms of electromagnetic response formation within sounding systems with controlled and natural field excitation are being considered. It has been shown that for methods with natural field excitation theoretical accents are inevitably removed to the side of taking into account the spherical nature of its sourses. Taking this circumstance into consideration, general theory of impedance measurements is being developed which is based on introduction of two scalar parameters of impedant type. Much attention has been paid to studies of interaction of electromagnetic waves of HF and SHF ranges with background geological medium which is a complex multiphase system penetrated by heterogeneous electron-ion flows which are formed in particular above tectonically located hydrocarbon deposits favourable for appearance of "transparency windows" at the hybrid, plasma and cyclotron resonance frequencies. The role and importance of these flows for distribution of electric charges within near-earth air layer is being discussed as well as their volumetric density which is, according to experimental evidences, strongly differentiated by area. The idea of compex application of radiowave sounding systems, united by the single physical mechanism of anomalies formation due to appearance of free charge carriers in some considered medium with measurement of electrostatic field in near-earth atmospheric layer has been proposed.

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