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时间域电磁(TDEM)响应常与导体中存在的涡流有关,因为这是主导效应。然而,其它效应如由介电过程产生的位移电流和与岩石磁化有关的磁场,也对TDEM响应产生影响。本文将分析磁化对TDEM数据的影响。我们使用Wang和Hohmann(1993)研制的以有限差分法为基础的数值计算方法TDEM3DL来研究瞬变电磁场在一种介质中的传播,这种介质所含的物体既有异常导电体又有异常导磁体。惊人的结果是,兼有异常导电性和异常导磁性的物体比仅有纯导电异常或纯导磁异常的物体对TDEM的异常响应大得多。这种效应在解释可能具有导磁性的电性不均匀构造上的TDEM资料时必须予以考虑。
The time-domain electromagnetic (TDEM) response is often related to the presence of eddy currents in the conductor as this is the dominant effect. However, other effects such as the displacement current generated by the dielectric process and the magnetic field associated with rock magnetization also have an impact on the TDEM response. This article will analyze the effect of magnetization on TDEM data. We use the TDEM3DL, a numerical method based on the finite difference method developed by Wang and Hohmann (1993), to study the propagation of transient electromagnetic fields in a medium that contains both anomalous and abnormal conductors magnet. The astonishing result is that both the abnormally conductive and the abnormally conductive objects have a far greater anomalous response to TDEM than those with only purely conductive or purely conductive anomalies. This effect must be accounted for in interpreting TDEM data on electrically inhomogeneous structures that may have magnetism.