瞬变电磁场的波场变换算法

Wave-field conversion method for transient electromagnetic field

瞬变电磁场的波场变换拟地震解释是目前电磁勘探领域中一项很有前景的解释方法，而实现瞬变电磁场的波场变换又是其中的关键。本文基于物理场所满足的基本方程，推导出了适于多种场源激发方式及观测分量的波场变换公式及其数值离散形式。由于波场变换问题为不适定问题，故我们采用奇异值分解算法实现了瞬变电磁场的波场变换，并针对影响波场变换的诸因素（阻尼系数α的选取，时窗宽度、误差）进行了系统研究和计算，证明了我们研究的算法稳定、快速、精度高。

Pseudo-seismic interpretation of transient electromagnetic field after wave field conversion is a very promising interpretation method in electromagnetic survey,and the wave field conversion of transient electromagnetic field is a key step. The wave field conversion formula (or their discrete forms)which are suitable to both some source shot ways and several kinds of observation components are derived form basic equations of physical field. The singular value decomposition is used to achieve the wave field conversion of transient electromagnetic field because the wave field con-version problem is an ill-posted problem. Authors have made a series of analysis and computation which are relating to some factors influencing the wave field conversion, such as the choice of damping coefficient a, window width and error. The method is proved stable,fast and accurate.