基于节点有限元与矢量有限元的可控源电磁三维正演对比

基于电场的可控源电磁三维有限元正演模拟早期主要采用节点有限元法，但因存在伪解问题而影响求解效率和精度；避免出现伪解的有效手段之一是采用基于棱边元的矢量有限元法，该方法近年在电磁三维模拟中逐步得到应用推广。为了更具体地了解两种方法在三维电磁正演中的实际应用效果，开展了两种方法的对比试验。首先从边值问题的建立进行讨论，之后分别通过一个水平层状介质模型和单一低阻体模型对两种方法的正演结果及效率进行比较。实际模拟结果表明：同等条件下，矢量有限元法计算精度更高，但其计算速度较节点有限元法约慢一半。

Comparison of 3D controlled-source electromagnetic forward modeling based on the nodal finite element and the edge-based finite element

In the early stage,the nodal element was mainly used for the forward modeling of the 3D controlled-source electromagnetic (EM) responses,but its spurious mode affected calculation efficiency and solution accuracy.The edge-based finite element method is increasingly adopted in the 3D EM modeling since it can avoid spurious solutions.To study details of the efficiency and accuracy between these two methods,comparison experiments are carried out.First the construction of the boundary-value problem is discussed.Then the forward modeling based on these two methods are achieved on both a horizontal-layered model and a single low-resistivity body model.Our comparison experiments show that under the same modeling condition,the result accuracy with the edge-based finite element is better than that with the nodal element while the edge element is slower than the nodal element as the first one spends about twice of calculation time of the latter one.