Traditional transient electromagnetic methods use single sources for excitation and extract the characteristics of underground media by improving interpretation technology. This study focused the improvements of transient electromagnetic interpretation using complex source technology. A time-domain vector finite element method (TFEM) was applied on three-dimensional forward modelling of semi-airborne transient electromagnetic (TEM) with multiple electrical sources, and it analysed the characteristics of fields with multiple sources. The study used a model of an isolated anomalous body in a homogeneous medium as an example. The effects of different combinations of excitation sources on the distributions of the magnetic field characteristics were analysed. Numerical results showed that the magnetic field components in a specific area could be strengthened by changing the layout of the sources, which was significant for future field data collections. By comparing the transient electromagnetic fields of the vertical array dipole sources with that of the loop source, the anomaly transient electromagnetic field of multi-source was more obvious than the field with a single source. Taking a complex orebody model as an example, a cross-electric source was used to calculate the magnetic field components of the semi-airborne TEM method. The resistivity distribution characteristics of the underground medium were obtained using an apparent resistivity interpretation method of the vertical magnetic field, which fully demonstrated that a multi-source transient electromagnetic system had the ability to determine abundant resistivity information of a complex medium.

中文翻译：

---

使用TFEM的多源半机TEM系统的数值建模分析

传统的瞬变电磁方法使用单一来源进行激励，并通过改进解释技术来提取地下介质的特征。这项研究集中于使用复杂源技术改进瞬态电磁解释。将时域矢量有限元方法（TFEM）用于多电源半机载瞬变电磁（TEM）的三维正向建模，并分析了多电源场的特性。该研究以均匀介质中孤立的异常体模型为例。分析了激发源的不同组合对磁场特性分布的影响。数值结果表明，可以通过改变信号源的布局来增强特定区域的磁场分量，这对于将来的现场数据采集具有重要意义。通过将垂直阵列偶极子源的瞬变电磁场与环路源的瞬变电磁场进行比较，发现多源异常瞬变电磁场比单源异常场明显。以一个复杂的矿体模型为例，使用交叉电源来计算半机载TEM方法的磁场分量。地下介质的电阻率分布特性是使用垂直磁场的视电阻率解释方法获得的，