The Research Of Moving Source Electromagnetic Imaging Method

We research the time-domain electromagnetic field curve characteristics of horizontal electric dipole source base on the diffusion theroy of transient electromagnetic field theory and the horizontal electric dipole source underground impulse response characteristics,.By using the Maxwell equations, we derived the electric dipole excitation source the time domain electromagnetic response. And we calculated electromagnetic field of isotropic layered on the surface about horizontal dipole source. Finally, analysis the apparent resistivity curve features of multi-layered ground model. By using positive cosine transform,we discuss horizontal electric dipole time domain forward problem.Article introduces a new electromagnetic imaging method-moving source electromagnetic imaging method. The method is based CSAMT method acquisition system to realize the moving source transient electromagnetic method method and applied.Under uniform half-space and layered media model, we main analyzes the curve characteristics, in particular the relationship of the peak amplitude and the apparent resistivity, the theoretical basis for the establishment of moving source imaging methods. One of the major imaging modalities proposed for the CR method sectional imaging. Observations in the field, by moving the ground floor horizontal electic diploe source emits transient electromagnetic field, fixed ground observation points measured online walkaway of transient electromagnetic sounding, achieving the moving electric diploe source transient electromagnetic (MSTEM) Imaging Methods. apparent resistivity imaging of MSTEM method take a combination of single-source and multi-source computing approach to calculate imaging parameters.MSTEM method observe data in two aspects:multiple superimposed and multiple coverage of space and time. When observing surface element does not move, we receive from multiple observations,.the observed data normalization process can solve non-uniqueness of the inverse problem, thus forming a new moving source electromagnetic detection methods.Underground apparent resistivity information at the same depth, you can obtain the apparent resistivity information from the corresponding separation between receiver and transmitter. It is noteworthy that the electric field component of the impulse response decay time derivative to get the value of peak time, so that the apparent resistivity can be obtained at this time, it does not mean that this apparent resistivity of the ground stand for the real resistivity at this point, but it is the comprehensive reflection of apparent resistivity underground layered media. By studying changes in the apparent resistivity, we can provide some reference for tracking the top part of the abnormal body interface.